ISO/FDIS 683-3

Heat-treatable steels, alloy steels and free-cutting steels

Aciers pour traitement thermique, aciers alliés et aciers pour décolletage

General Information

• Status: Published
• ICS: 77.140.10 - Heat-treatable steels
• ICS: 77.140.20 - Stainless steels
• Technical Committee: ISO/TC 17/SC 4 - Heat treatable and alloy steels
• Drafting Committee: ISO/TC 17/SC 4 - Heat treatable and alloy steels
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 22-Oct-2021
• Completion Date: 22-Oct-2021

RELATIONS

• Revised: ISO 683-3:2019 - Heat-treatable steels, alloy steels and free-cutting steels
• Effective Date: 23-Apr-2020

Standards Content (sample)

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 683-3
ISO/TC 17/SC 4
Heat-treatable steels, alloy steels and
Secretariat: DIN
free-cutting steels —
Voting begins on:
2021-04-07
Part 3:
Voting terminates on:
Case-hardening steels
2021-06-02
Aciers pour traitement thermique, aciers alliés et aciers pour
décolletage —
Partie 3: Aciers pour cémentation
ISO/CEN PARALLEL PROCESSING
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 683-3:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. ISO 2021
---------------------- Page: 1 ----------------------
ISO/FDIS 683-3:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting

on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address

below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 683-3:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Classification and designation ............................................................................................................................................................... 3

4.1 Classification ............................................................................................................................................................................................. 3

4.2 Designation ................................................................................................................................................................................................ 3

5 Information to be supplied by the purchaser......................................................................................................................... 3

5.1 Mandatory information ................................................................................................................................................................... 3

5.2 Options and/or supplementary or special requirements .................................................................................. 3

6 Manufacturing process .................................................................................................................................................................................. 4

6.1 General ........................................................................................................................................................................................................... 4

6.2 Deoxidation ................................................................................................................................................................................................ 4

6.3 Heat-treatment condition and surface condition at delivery ......................................................................... 4

6.3.1 Normal condition at delivery ................................................................................................................................ 4

6.3.2 Particular heat-treatment condition .................. ............................................................................................. 4

6.3.3 Particular surface conditions ................................................................................................................................ 4

6.4 Traceability of the cast ..................................................................................................................................................................... 4

7 Requirements .......................................................................................................................................................................................................... 5

7.1 Chemical composition, hardness and hardenability .............................................................................................. 5

7.1.1 General...................................................................................................................................................................................... 5

7.1.2 Hardenability ...................................................................................................................................................................... 5

7.1.3 Chemical composition ................................................................................................................................................. 5

7.2 Machinability ............................................................................................................................................................................................ 5

7.3 Cold shearability .................................................................................................................................................................................... 5

7.4 Grain size ...................................................................................................................................................................................................... 6

7.5 Non-metallic inclusions ................................................................................................................................................................... 6

7.5.1 Microscopic inclusions ............................................................................................................................................... 6

7.5.2 Macroscopic inclusions .............................................................................................................................................. 6

7.6 Internal soundness .............................................................................................................................................................................. 6

7.7 Surface condition .................................................................................................................................................................................. 6

7.8 Shape, dimensions and tolerances ......................................................................................................................................... 7

8 Inspection .................................................................................................................................................................................................................... 7

8.1 Testing procedures and types of documents ................................................................................................................ 7

8.2 Frequency of testing ........................................................................................................................................................................... 7

8.3 Tests to be carried out for specific inspection ............................................................................................................. 7

8.3.1 General...................................................................................................................................................................................... 7

8.3.2 Visual and dimensional inspection .................................................................................................................. 7

9 Test methods ............................................................................................................................................................................................................. 8

9.1 Chemical analysis .................................................................................................................................................................................. 8

9.2 Hardness and hardenability tests ........................................................................................................................................... 8

9.2.1 Verification of hardness ............................................................................................................................................. 8

9.2.2 Verification of hardenability .................................................................................................................................. 8

9.3 Retests ............................................................................................................................................................................................................ 8

10 Marking .......................................................................................................................................................................................................................... 8

Annex A (normative) Supplementary or special requirements ............................................................................................31

Annex B (informative) Designation of steels given in this document and of comparable

grades covered in various designation systems................................................................................................................33

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ISO/FDIS 683-3:2021(E)

Annex C (informative) Dimensional standards applicable to products complying with this

document ...................................................................................................................................................................................................................35

Annex D (informative) Classification of steel grades according to minimum tensile strength

as a function of diameter after hardening and tempering at 200 °C ...........................................................36

Bibliography .............................................................................................................................................................................................................................37

iv © ISO 2021 – All rights reserved
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ISO/FDIS 683-3:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/ directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO’s adherence to the

World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 4, Heat

treatable and alloy steels.

This fourth edition cancels and replaces the third edition (ISO 683-3:2019), which has been technically

revised. The main changes compared with the previous edition are as follows:
— steel grades 23MnCrMo5-5-4 and 17NiCrMoS6-4 have been added;

— the lower silicon content in Table 3 has been deleted and replaced by a new option A.4 in Annex A;

A list of all parts in the ISO 683 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
© ISO 2021 – All rights reserved v
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 683-3:2021(E)
Heat-treatable steels, alloy steels and free-cutting steels —
Part 3:
Case-hardening steels
1 Scope
This document specifies the technical delivery requirements for:
— semi-finished products, hot formed, e.g. blooms, billets, slabs (see NOTE 1);
— bars (see NOTE 1);
— wire rod;
— finished flat products, and
— hammer or drop forgings (see NOTE 1)

manufactured from the case-hardening non-alloy or alloy steels listed in Table 3 and supplied in one

of the heat-treatment conditions given for the different types of products in Table 1 and in one of the

surface conditions given in Table 2.

The steels are, in general, intended for the manufacture of case-hardened machine parts.

NOTE 1 Hammer-forged semi-finished products (blooms, billets, slabs, etc.), seamless rolled rings and

hammer-forged bars are covered under semi-finished products or bars and not under the term “hammer and

drop forgings”.

NOTE 2 Steels complying with the requirements for the chemical composition in Table 3, but supplied in other

product forms or treatment conditions are outside the scope of the document..
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 377:2017, Steel and steel products — Location and preparation of samples and test pieces for

mechanical testing
ISO 404:2013, Steel and steel products — General technical delivery requirements
ISO 642:1999, Steel — Hardenability test by end quenching (Jominy test)
ISO 643:2019, Steels — Micrographic determination of the apparent grain size
ISO 4885:2018, Ferrous materials — Heat treatments — Vocabulary

ISO 4948-1:1982, Steels — Classification — Part 1: Classification of steels into unalloyed and alloy steels

based on chemical composition

ISO 4948-2:1981, Steels — Classification — Part 2: Classification of unalloyed and alloy steels according to

main quality classes and main property or application characteristics
ISO/TS 4949:2016, Steel names based on letter symbols
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ISO/FDIS 683-3:2021(E)

ISO 4967:2013, Steel — Determination of content of non-metallic inclusions — Micrographic method using

standard diagrams

ISO 6506-1:2014, Metallic materials — Brinell hardness test — Part 1: Test method

ISO 6508-1:2016, Metallic materials — Rockwell hardness test — Part 1: Test method

ISO 6929:2013, Steel products — Vocabulary

ISO 7788:—, Steel — Surface finish of hot-rolled plates and wide flats — Delivery requirements

ISO 9443:2018, Surface quality classes for hot-rolled bars and wire rod
ISO/TR 9769:2018, Steel and iron — Review of available methods of analysis
ISO 10474:2013, Steel and steel products — Inspection documents

ISO 14284:1996, Steel and iron — Sampling and preparation of samples for the determination of chemical

composition
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 377:2017, ISO 4885:2018,

ISO 4948-1:1982, ISO 4948-2:1981, ISO 6929:2013, ISO 14284:1996 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
steel

material with iron as the predominant element, having a carbon content generally less than 2,0 % and

containing other elements

Note 1 to entry: A limited number of chromium steels can have more than 2,0 % carbon, but 2,0 % is the usual

dividing line between steel and cast iron.

Note 2 to entry: Steels are classified as unalloyed steels and alloy steels (see ISO 4948-1:1982, 3.1.1.1 to 3.1.1.4).

[SOURCE: ISO 4948-1:1982, Clause 2, modified — Notes 1 and 2 to entry have been added.]

3.2
case-hardening steel

steel (3.1) with a relatively low carbon content, which are carburized or carbonitrided on their surface

and subsequently hardened

Note 1 to entry: These steels, after hardening, have a high degree of hardness in the surface zone and good

resistance to wear, while the core material is characterized principally by extreme toughness.

Note 2 to entry: Further, possibilities for heat treatment of case-hardening steels are, for example, nitrocarburizing

and nitriding.
1) Under preparation. (Stage ate the time of publication: ISO/FDIS 7788:2021.)
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ISO/FDIS 683-3:2021(E)
4 Classification and designation
4.1 Classification

The classification of the relevant steel grades is in accordance with ISO 4948-1 and ISO 4948-2. Steel

grades C10E, C10R, C15E, C15R, C16E, C16R and 22Mn6 are non-alloy special steels. All other steel

grades covered by this document are alloy special steels.
4.2 Designation

For the steel grades covered by this document, the steel names as given in the relevant tables shall be

allocated in accordance with ISO/TS 4949.

A comparison between the designation of steels given in this document with various designation

systems is given in Annex B.
5 Information to be supplied by the purchaser
5.1 Mandatory information

The following information shall be supplied by the purchaser at the time of enquiry and order:

a) quantity to be delivered;

b) designation of the product form (slab, bloom, billet, round bar, square or hexagonal bar, wire rod,

wide flats, sheet, plate, strip, forging, etc.);

c) either the designation of the dimensional standard(s) and the dimensions and tolerances selected

from this or these (see 7.8) or, for example, in the case of drop forgings, the designation of the

drawing or any other document covering the dimensions and tolerances required for the product;

d) a reference to this document, i.e. ISO 683-3:2021;
e) the designation of the steel type given in Table 3;

f) standard designation for a test report 2.2 or, if required, any other type of inspection document in

accordance with ISO 10474 or another equivalent standard, e.g. EN 10204 or JIS G 0415.

5.2 Options and/or supplementary or special requirements

A number of options are specified in this document and listed below. If the purchaser does not indicate

the wish to implement any of these options, the products are supplied in accordance with the basic

specifications of this document (see 5.1):

a) if a heat-treatment condition other than the untreated condition is required, the symbol for this

other condition (see Table 1, column 2);

b) if a surface condition other than “hot worked” or a special surface quality is required, the surface

condition (see Table 2) and the surface quality (see 7.7.3);

c) any requirement for restricted hardenability scatter bands for alloy steels (+HH, +HL; see 7.1.1,

Table 6 and Figure 1);

d) if any supplementary requirement shall be complied with, the symbol and, where necessary, the

details of this supplementary requirement in accordance with Annex A;

e) any requirement for the verification of non-metallic inclusion content (see 7.5);

f) verification of hardenability and, if agreed, the information about calculation of the hardenability

(see 9.2.2);
© ISO 2021 – All rights reserved 3
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ISO/FDIS 683-3:2021(E)

g) any requirement concerning suitability of bars and rod for bright drawing (see 7.7.4);

h) any requirement relating to removal of surface defects (see 7.7.5).

EXAMPLE 50 hot-rolled round bars in accordance with ISO 1035-1 with a nominal diameter of 40 mm and

a nominal length of 8 000 mm with diameter tolerance according to class S and with length tolerance according

to class L2 of ISO 1035-4 made of steel grade ISO 683-3, 20MnCr5 (see Table 3) in the heat-treatment condition

annealed (+A), surface blast cleaned (+BC) (see Table 2), product analysis/option A.3 with an inspection

certificate 3.1 in accordance with ISO 10474.
50 Round bars ISO 1035 – 40,0S × 8 000L2
ISO 683-3 – 20MnCr5+A+BC, Option A.3
ISO 10474 – 3.1
6 Manufacturing process
6.1 General

The manufacturing process of the steel and of the products is left to the discretion of the manufacturer,

with the restrictions given by the requirements in 6.2 and 6.4.

For minimum reduction ratio or minimum thickness deformation ratio of rolled and forged products,

see A.5.
6.2 Deoxidation
All steels shall be fully deoxidized.
6.3 Heat-treatment condition and surface condition at delivery
6.3.1 Normal condition at delivery

Unless otherwise agreed at the time of enquiry and order, the products shall be delivered in the

untreated condition, i.e. hot-worked condition.
6.3.2 Particular heat-treatment condition

If so agreed at the time of enquiry and order, the products shall be delivered in one of the heat-treatment

conditions given in Table 1, row numbers 3 to 8.
6.3.3 Particular surface conditions

If so agreed at the time of enquiry and order, the products shall be delivered in one of the particular

surface conditions given in Table 2, row numbers 3 to 6.
6.4 Traceability of the cast
The products shall be traceable to the cast, see Clause 10.
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ISO/FDIS 683-3:2021(E)
7 Requirements
7.1 Chemical composition, hardness and hardenability
7.1.1 General

Table 1 gives a survey on combinations of usual heat-treatment conditions at delivery, product forms

and requirements as specified in Tables 3 to 7 (chemical composition, hardenability, maximum hardness

and hardness range).

In special cases, variations in these technical delivery requirements or additions to them can form the

subject of an agreement at the time of enquiry and order (see 5.2 and Annex A).

In addition to this document, the general technical delivery requirements of ISO 404 apply.

7.1.2 Hardenability

Unless otherwise agreed for alloy steels, the hardenability requirements given in Table 5 apply. If

agreed at the time of enquiry and order, alloy steels with restricted hardenability scatter bands given

in Table 6 or shown in Figure 1 shall be supplied.

A classification of steel grades according to minimum tensile strength as a function of diameter after

hardening and tempering is given in Annex D.
7.1.3 Chemical composition

The chemical composition determined by cast analysis shall conform with the values in Table 3.

Permissible deviations between the limiting values for cast analysis and the values for product analysis

are given in Table 4.

The product analysis shall be carried out when specified, at the time of the enquiry and order (see A.3).

7.2 Machinability

All steels are machinable in the conditions “soft-annealed”, “treated to hardness range”, “treated to

ferrite/pearlite structure” and “normalized.

Lowering the silicon content can have a negative influence on the machinability. For details on a

minimum silicon content, see A.4.

Where improved machinability is required, the grades with a specified sulfur range should be ordered

and/or with a specific treatment to improve machinability (see also Table 3, footnote b).

7.3 Cold shearability

7.3.1 Under suitable shearing conditions (avoiding local stress peaks, preheating, application of blades

with a profile adapted to that of the product, etc.), all steels are cold shearable in the condition “soft-

annealed”.

7.3.2 Under suitable conditions, steel grades 28Cr4, 28CrS4, 20MnCr5, 20MnCrS5, 24CrMo4,

24CrMoS4, 22CrMoS3-5, 20MoCr4, 20MoCrS4, 16NiCr4, 16NiCrS4, 18NiCr5-4, 17CrNi6-6, 15NiCr13,

17NiCrMo6-4, 23MnCrMo5-5-4 and 18CrNiMo7-6, are also cold shearable when delivered in the

condition “treated to improve shearability” with the hardness requirements given in Table 7.

7.3.3 Under suitable conditions, the non-alloy steels and steels 17Cr3, 17CrS3, 20Cr4, 20CrS4,

16MnCr5, 16MnCrS5, 16MnCrB5, 18CrMo4, 18CrMoS4, 20NiCrMo2-2 and 20NiCrMoS2-2 are cold

shearable when delivered in the untreated condition.
© ISO 2021 – All rights reserved 5
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ISO/FDIS 683-3:2021(E)
7.4 Grain size

Unless otherwise agreed at the time of enquiry and order, the steel shall show a fine grain structure

with an austenitic grain size of 5 and finer, when tested in accordance with ISO 643. For verification,

see A.1.
7.5 Non-metallic inclusions
7.5.1 Microscopic inclusions

The special steels shall have a certain degree of cleanness. However, verification of the non-metallic

inclusion content requires a special agreement. If there is such an agreement at the time of enquiry and

order, the microscopic non-metallic inclusion content shall be determined to an agreed procedure and

within agreed limits in accordance with ISO 4967 or another equivalent standard.

For grades with specified minimum sulfur content, the agreement should not include sulfides.

7.5.2 Macroscopic inclusions

This requirement is applicable to the verification of the macroscopic inclusions in special steels. If

verification is agreed, the method and acceptance limits shall be agreed at the time of enquiry and order.

7.6 Internal soundness

Where appropriate, requirements relating to the internal soundness of the products shall be agreed at

the time of inquiry and order (see A.2).
7.7 Surface condition

7.7.1 All products shall have a smooth surface finish appropriate to the manufacturing processes

applied.

7.7.2 Minor surface imperfections which can occur under normal manufacturing conditions, such as

prints originating from rolled-in scale, shall not be regarded as defects.

7.7.3 Bars and wire rod are delivered with surface class A in accordance with ISO 9443 and hot-rolled

plates and wide flats shall be delivered with a surface in accordance with ISO 7788, unless otherwise

agreed at the time of enquiry and order.

Where no International Standard on the surface quality of steel products exists, and where appropriate,

detailed requirements referring to this characteristic shall be agreed at the time of enquiry and order.

It is more difficult to detect and eliminate surface discontinuities from coiled products than from cut

lengths. This should be taken into account when agreements on surface quality are made.

NOTE Bars and wire rod for cold heading and cold extrusion are covered fully by ISO 4954.

7.7.4 If suitability of bars and rod for bright drawing is required, this shall be agreed at the time of

enquiry and order.

7.7.5 Removal of surface discontinuities by welding shall only be permitted with the approval of the

customer or his or her representative. If surface discontinuities are repaired, the method and maximum

depth of removal shall be agreed at the time of enquiry and order.
6 © ISO 2021 – All rights reserved
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ISO/FDIS 683-3:2021(E)
7.8 Shape, dimensions and tolerances

The nominal dimensions, tolerances on dimensions and shape of the product shall be agreed at the time

of enquiry and order, if possible, with reference to the dimensional standards applicable (see Annex C).

8 Inspection
8.1 Testing procedures and types of documents
8.1.1 Products complying with this document shall be ord
...

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 683-3
ISO/TC 17/SC 4
Heat-treatable steels, alloy steels and
Secretariat: DIN
free-cutting steels —
Voting begins on:
2021-10-22
Part 3:
Voting terminates on:
Case-hardening steels
2021-12-17
Aciers pour traitement thermique, aciers alliés et aciers pour
décolletage —
Partie 3: Aciers pour cémentation
ISO/CEN PARALLEL PROCESSING
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 683-3:2021(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
NATIONAL REGULATIONS. © ISO 2021
---------------------- Page: 1 ----------------------
ISO/FDIS 683-3:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may

be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on

the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below

or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
© ISO 2021 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 683-3:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ..................................................................................................................................................................................... 1

3 Terms and definitions .................................................................................................................................................................................... 2

4 Classification and designation .............................................................................................................................................................. 2

4.1 Classification ............................................................................................................................................................................................ 2

4.2 Designation ................................................................................................................................................................................................ 3

5 Information to be supplied by the purchaser ....................................................................................................................... 3

5.1 Mandatory information .................................................................................................................................................................. 3

5.2 Options and/or supplementary or special requirements ................................................................................. 3

5.3 Ordering example................................................................................................................................................................................. 3

6 Manufacturing process ................................................................................................................................................................................. 4

6.1 General ........................................................................................................................................................................................................... 4

6.2 Deoxidation................................................................................................................................................................................................ 4

6.3 Heat-treatment condition and surface condition at delivery ........................................................................ 4

6.3.1 Normal condition at delivery .................. ................................................................................................................. 4

6.3.2 Particular heat-treatment condition ................................................................................................................ 4

6.3.3 Particular surface conditions ................................................................................................................................. 4

6.4 Traceability of the cast .................................................................................................................................................................... 4

7 Requirements .......................................................................................................................................................................................................... 4

7.1 Chemical composition, hardness and hardenability ............................................................................................. 4

7.1.1 General ........................................................................................................................................................................................ 4

7.1.2 Hardenability ...................................................................... ................................................................................................... 5

7.1.3 Chemical composition ........................................................................................................................................... ......... 5

7.2 Machinability ........................................................................................................................................................................................... 5

7.3 Cold shearability ................................................................................................................................................................................... 5

7.4 Grain size ..................................................................................................................................................................................................... 5

7.5 Non-metallic inclusions .................................................................................................................................................................. 6

7.5.1 Microscopic inclusions .................................................................................................................................................. 6

7.5.2 Macroscopic inclusions ................................................................................................................................................. 6

7.6 Internal soundness ............................................................................................................................................................................. 6

7.7 Surface condition .................................................................................................................................................................................. 6

7.8 Shape, dimensions and tolerances ........................................................................................................................................ 6

8 Inspection .................................................................................................................................................................................................................... 7

8.1 Testing procedures and types of documents............................................................................................................... 7

8.2 Frequency of testing .......................................................................................................................................................................... 7

8.3 Tests to be carried out for specific inspection ........................................................................................................... 7

8.3.1 General ........................................................................................................................................................................................ 7

8.3.2 Visual and dimensional inspection .................................................................................................................... 7

9 Test methods ............................................................................................................................................................................................................ 8

9.1 Chemical analysis ................................................................................................................................................................................. 8

9.2 Hardness and hardenability tests ......................................................................................................................................... 8

9.2.1 Verification of hardness ............................................................................................................................................... 8

9.2.2 Verification of hardenability .................................................................................................................................... 8

9.3 Retests ........................................................................................................................................................................................................... 8

10 Marking ........................................................................................................................................... ............................................................................... 8

Annex A (normative) Supplementary or special requirements ..........................................................................................31

Annex B (informative) Designation of steels given in this document and of comparable

grades covered in various designation systems .............................................................................................................33

iii
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ISO/FDIS 683-3:2021(E)

Annex C (informative) Classification of steel grades according to minimum tensile strength

as a function of diameter after hardening and tempering at 200 °C .........................................................35

Bibliography .............................................................................................................................................................................................................................36

© ISO 2021 – All rights reserved
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ISO/FDIS 683-3:2021(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO’s adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 4, Heat

treatable and alloy steels.

This fourth edition cancels and replaces the third edition (ISO 683-3:2019), which has been technically

revised. The main changes compared with the previous edition are as follows:
— steel grades 23MnCrMo5-5-4 and 17NiCrMoS6-4 have been added;

— the lower silicon content in Table 3 has been deleted and replaced by a new option in Clause A.4.

A list of all parts in the ISO 683 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www.iso.org/members.html.
© ISO 2021 – All rights reserved
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 683-3:2021(E)
Heat-treatable steels, alloy steels and free-cutting steels —
Part 3:
Case-hardening steels
1 Scope
This document specifies the technical delivery requirements for
— semi-finished products, hot formed (e.g. blooms, billets, slabs) (see NOTE 1),
— bars (see NOTE 1),
— wire rod,
— finished flat products, and
— hammer or drop forgings (see NOTE 1)

manufactured from the case-hardening non-alloy or alloy steels listed in Table 3 and supplied in one

of the heat-treatment conditions given for the different types of products in Table 1 and in one of the

surface conditions given in Table 2.

The steels are, in general, intended for the manufacture of case-hardened machine parts.

NOTE 1 Hammer-forged semi-finished products (blooms, billets, slabs, etc.), seamless rolled rings and

hammerforged bars are covered under semi-finished products or bars and not under the term “hammer and drop

forgings”.

NOTE 2 For International Standards relating to steels conforming with the requirements for the chemical

composition in Table 3, however, supplied in other product forms or treatment conditions than given above or

intended for special applications, and for other related International Standards, see the Bibliography.

2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements of this document. For dated references, only the edition cited applies. For

undated references, the latest edition of the referenced document (including any amendments) applies.

ISO 377, Steel and steel products — Location and preparation of samples and test pieces for mechanical

testing
ISO 404, Steel and steel products — General technical delivery requirements
ISO 642:1999, Steel — Hardenability test by end quenching (Jominy test)
ISO 643, Steels — Micrographic determination of the apparent grain size
ISO 4885, Ferrous materials — Heat treatments — Vocabulary

ISO 4948-1, Steels — Classification — Part 1: Classification of steels into unalloyed and alloy steels based

on chemical composition

ISO 4948-2, Steels — Classification — Part 2: Classification of unalloyed and alloy steels according to main

quality classes and main property or application characteristics
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ISO/FDIS 683-3:2021(E)
ISO/TS 4949, Steel names based on letter symbols

ISO 4967, Steel — Determination of content of non-metallic inclusions — Micrographic method using

standard diagrams
ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method
ISO 6929, Steel products — Vocabulary

ISO 7788, Steel — Surface finish of hot-rolled plates and wide flats — Delivery requirements

ISO 9443, Surface quality classes for hot-rolled bars and wire rod
ISO/TR 9769, Steel and iron — Review of available methods of analysis
ISO 10474, Steel and steel products — Inspection documents

ISO 14284, Steel and iron — Sampling and preparation of samples for the determination of chemical

composition
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 377, ISO 4885, ISO 4948-1,

ISO 4948-2, ISO 6929, ISO 14284 and the following apply.

NOTE For deviations from these terms and definitions, see NOTE 1 of the Scope and footnote b of Table 2.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
case-hardening steel

steel with a relatively low carbon content, which are carburized or carbonitrided on their surface and

subsequently hardened

Note 1 to entry: These steels, after hardening, have a high degree of hardness in the surface zone and good

resistance to wear, while the core material is characterized principally by extreme toughness.

Note 2 to entry: Further possibilities for heat treatment of case-hardening steels are, for example, nitrocarburizing

and nitriding.
3.2
non-alloy steel
as defined in ISO 4948-1
3.3
alloy steel
as defined in ISO 4948-1
4 Classification and designation
4.1 Classification

The classification of the relevant steel grades is in accordance with ISO 4948-1 and ISO 4948-2. Steel

grades C10E, C10R, C15E, C15R, C16E, C16R and 22Mn6 are non-alloy special steels. All other steel

grades covered by this document are alloy special steels.
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ISO/FDIS 683-3:2021(E)
4.2 Designation

For the steel grades covered by this document, the steel names as given in the relevant tables shall be

allocated in accordance with ISO/TS 4949.

A comparison between the designation of steels given in this document with various designation

systems is given in Annex B.
5 Information to be supplied by the purchaser
5.1 Mandatory information

The following information shall be supplied by the purchaser at the time of enquiry and order:

a) quantity to be delivered;

b) designation of the product form (slab, bloom, billet, round bar, square or hexagonal bar, wire rod,

wide flats, sheet, plate, strip, forging, etc.);

c) either the designation of the dimensional standard(s) and the dimensions and tolerances selected

from this or these (see 7.8) or, for example, in the case of drop forgings, the designation of the

drawing or any other document covering the dimensions and tolerances required for the product;

d) a reference to this document, i.e. ISO 683-3;
e) the designation of the steel type given in Table 3;

f) standard designation for a test report 2.2 or, if required, any other type of inspection document in

accordance with ISO 10474 or another equivalent standard, e.g. EN 10204 or JIS G 0415.

5.2 Options and/or supplementary or special requirements

A number of options are specified in this document and listed below. If the purchaser does not indicate

the wish to implement any of these options, the products are supplied in accordance with the basic

specifications of this document (see 5.1):

a) if a heat-treatment condition other than the untreated condition is required, the symbol for this

other condition (see Table 1, column 2);

b) if a surface condition other than “hot worked” or a special surface quality is required, the surface

condition (see Table 2) and the surface quality (see 7.7.3);

c) any requirement for restricted hardenability scatter bands for alloy steels (+HH, +HL; see 7.1.1,

Table 6 and Figure 1);

d) if any supplementary requirement shall be complied with, the symbol and, where necessary, the

details of this supplementary requirement in accordance with Annex A;

e) any requirement for the verification of non-metallic inclusion content (see 7.5);

f) verification of hardenability and, if agreed, the information about calculation of the hardenability

(see 9.2.2);

g) any requirement concerning suitability of bars and rod for bright drawing (see 7.7.4);

h) any requirement relating to removal of surface defects (see 7.7.5).
5.3 Ordering example
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ISO/FDIS 683-3:2021(E)

EXAMPLE 50 hot-rolled round bars in accordance with ISO 1035-1 with a nominal diameter of 40 mm and

a nominal length of 8 000 mm with diameter tolerance according to class S and with length tolerance according

to class L2 of ISO 1035-4 made of steel grade ISO 683-3, 20MnCr5 (see Table 3) in the heat-treatment condition

annealed (+A), surface blast cleaned (+BC) (see Table 2), product analysis/option A.3 with an inspection

certificate 3.1 in accordance with ISO 10474.
50 Round bars ISO 1035 – 40,0S × 8 000L2
ISO 683-3 – 20MnCr5+A+BC, Option A.3
ISO 10474 – 3.1
6 Manufacturing process
6.1 General

The manufacturing process of the steel and of the products is left to the discretion of the manufacturer,

with the restrictions given by the requirements in 6.2 and 6.4.

For minimum reduction ratio or minimum thickness deformation ratio of rolled and forged products,

see Clause A.5.
6.2 Deoxidation
All steels shall be fully deoxidized.
6.3 Heat-treatment condition and surface condition at delivery
6.3.1 Normal condition at delivery

Unless otherwise agreed at the time of enquiry and order, the products shall be delivered in the

untreated condition, i.e. hot-worked condition.
6.3.2 Particular heat-treatment condition

If so agreed at the time of enquiry and order, the products shall be delivered in one of the heat-treatment

conditions given in Table 1, row numbers 3 to 8.
6.3.3 Particular surface conditions

If so agreed at the time of enquiry and order, the products shall be delivered in one of the particular

surface conditions given in Table 2, row numbers 3 to 6.
6.4 Traceability of the cast
The products shall be traceable to the cast, see Clause 10.
7 Requirements
7.1 Chemical composition, hardness and hardenability
7.1.1 General

Table 1 gives a survey on combinations of usual heat-treatment conditions at delivery, product forms

and requirements as specified in Tables 3 to 7 (chemical composition, hardenability, maximum hardness

and hardness range).
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ISO/FDIS 683-3:2021(E)

In special cases, variations in these technical delivery requirements or additions to them can form the

subject of an agreement at the time of enquiry and order (see 5.2 and Annex A).

In addition to this document, the general technical delivery requirements of ISO 404 apply.

7.1.2 Hardenability

Unless otherwise agreed for alloy steels, the hardenability requirements given in Table 5 apply. If

agreed at the time of enquiry and order, alloy steels with restricted hardenability scatter bands given

in Table 6 or shown in Figure 1 shall be supplied.

A classification of steel grades according to minimum tensile strength as a function of diameter after

hardening and tempering is given in Annex C.
7.1.3 Chemical composition

The chemical composition determined by cast analysis shall conform with the values in Table 3.

Permissible deviations between the limiting values for cast analysis and the values for product analysis

are given in Table 4.

The product analysis shall be carried out when specified, at the time of the enquiry and order (see

Clause A.3).
7.2 Machinability

All steels are machinable in the conditions “soft-annealed”, “treated to hardness range”, “treated to

ferrite/pearlite structure” and “normalized”.

Lowering the silicon content can have a negative influence on the machinability. For details on a

minimum silicon content, see Clause A.4.

Where improved machinability is required, the grades with a specified sulfur range should be ordered

and/or with a specific treatment to improve machinability (see also Table 3, footnote b).

7.3 Cold shearability

7.3.1 Under suitable shearing conditions (avoiding local stress peaks, preheating, application of

blades with a profile adapted to that of the product, etc.), all steels are cold shearable in the condition

“soft-annealed”.

7.3.2 Under suitable conditions, steel grades 28Cr4, 28CrS4, 20MnCr5, 20MnCrS5, 24CrMo4,

24CrMoS4, 22CrMoS3-5, 20MoCr4, 20MoCrS4, 16NiCr4, 16NiCrS4, 18NiCr5-4, 17CrNi6-6, 15NiCr13,

17NiCrMo6-4, 23MnCrMo5-5-4 and 18CrNiMo7-6, are also cold shearable when delivered in the

condition “treated to improve shearability” with the hardness requirements given in Table 7.

7.3.3 Under suitable conditions, the non-alloy steels and steels 17Cr3, 17CrS3, 20Cr4, 20CrS4,

16MnCr5, 16MnCrS5, 16MnCrB5, 18CrMo4, 18CrMoS4, 20NiCrMo2-2 and 20NiCrMoS2-2 are cold

shearable when delivered in the untreated condition.
7.4 Grain size

Unless otherwise agreed at the time of enquiry and order, the steel shall show a fine grain structure

with an austenitic grain size of 5 and finer, when tested in accordance with ISO 643. For verification,

see Clause A.1.
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ISO/FDIS 683-3:2021(E)
7.5 Non-metallic inclusions
7.5.1 Microscopic inclusions

The special steels shall have a certain degree of cleanness. However, verification of the non-metallic

inclusion content requires a special agreement. If there is such an agreement at the time of enquiry and

order, the microscopic non-metallic inclusion content shall be determined to an agreed procedure and

within agreed limits in accordance with ISO 4967 or another equivalent standard.

For grades with specified minimum sulfur content, the agreement should not include sulfides.

7.5.2 Macroscopic inclusions

This requirement is applicable to the verification of the macroscopic inclusions in special steels. If

verification is agreed, the method and acceptance limits shall be agreed at the time of enquiry and

order.
7.6 Internal soundness

Where appropriate, requirements relating to the internal soundness of the products shall be agreed at

the time of inquiry and order (see Clause A.2).
7.7 Surface condition

7.7.1 All products shall have a smooth surface finish appropriate to the manufacturing processes

applied.

7.7.2 Minor surface imperfections which can occur under normal manufacturing conditions, such as

prints originating from rolled-in scale, shall not be regarded as defects.

7.7.3 Bars and wire rod are delivered with surface class A in accordance with ISO 9443 and hot-rolled

plates and wide flats shall be delivered with a surface in accordance with ISO 7788, unless otherwise

agreed at the time of enquiry and order.

Where no International Standard on the surface quality of steel products exists, and where appropriate,

detailed requirements referring to this characteristic shall be agreed at the time of enquiry and order.

It is more difficult to detect and eliminate surface discontinuities from coiled products than from cut

lengths. This should be taken into account when agreements on surface quality are made.

NOTE Bars and wire rod for cold heading and cold extrusion are covered fully by ISO 4954.

7.7.4 If suitability of bars and rod for bright drawing is required, this shall be agreed at the time of

enquiry and order.

7.7.5 Removal of surface discontinuities by welding shall only be permitted with the approval of the

customer or his or her representative. If surface discontinuities are repaired, the method and maximum

depth of removal shall be agreed at the time of enquiry and order.
7.8 Shape, dimensions and tolerances

The nominal dimensions, tolerances on dimensions and shape of the product shall be agreed at the time

of enquiry and order, if possible, with reference to the dimensional standards listed in the Bibliography.

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ISO/FDIS 683-3:2021(E)
8 Inspection
8.1 Testing procedures and types of documents

8.1.1 Products complying with this document shall be ordered and delivered with one of the

inspection documents as specified in ISO 10474 or another equivalent standard, e.g. EN 10204 or

JIS G 0415. The type of document shall be agreed at the time of enquiry and order. If the order does not

contain any specification of this type, a test report shall be issued.

8.1.2 If, in accordance with the agreements made at the time of enquiry and order, a test report 2.2 is

to be provided, this shall cover the fol
...

PROJET
NORME ISO/FDIS
FINAL
INTERNATIONALE 683-3
ISO/TC 17/SC 4
Aciers pour traitement thermique,
Secrétariat: DIN
aciers alliés et aciers pour
Début de vote:
2021-10-22 décolletage —
Vote clos le:
Partie 3:
2021-12-17
Aciers pour cémentation
Heat-treatable steels, alloy steels and free-cutting steels —
Part 3: Case-hardening steels
TRAITEMENT PARALLÈLE ISO/CEN
LES DESTINATAIRES DU PRÉSENT PROJET SONT
INVITÉS À PRÉSENTER, AVEC LEURS OBSER-
VATIONS, NOTIFICATION DES DROITS DE PRO-
PRIÉTÉ DONT ILS AURAIENT ÉVENTUELLEMENT
CONNAISSANCE ET À FOURNIR UNE DOCUMEN-
TATION EXPLICATIVE.
OUTRE LE FAIT D’ÊTRE EXAMINÉS POUR
ÉTABLIR S’ILS SONT ACCEPTABLES À DES FINS
INDUSTRIELLES, TECHNOLOGIQUES ET COM-
Numéro de référence
MERCIALES, AINSI QUE DU POINT DE VUE
ISO/FDIS 683-3:2021(F)
DES UTILISATEURS, LES PROJETS DE NORMES
INTERNATIONALES DOIVENT PARFOIS ÊTRE
CONSIDÉRÉS DU POINT DE VUE DE LEUR POSSI-
BILITÉ DE DEVENIR DES NORMES POUVANT
SERVIR DE RÉFÉRENCE DANS LA RÉGLEMENTA-
TION NATIONALE. © ISO 2021
---------------------- Page: 1 ----------------------
ISO/FDIS 683-3:2021(F)
DOCUMENT PROTÉGÉ PAR COPYRIGHT
© ISO 2021

Tous droits réservés. Sauf prescription différente ou nécessité dans le contexte de sa mise en œuvre, aucune partie de cette

publication ne peut être reproduite ni utilisée sous quelque forme que ce soit et par aucun procédé, électronique ou mécanique,

y compris la photocopie, ou la diffusion sur l’internet ou sur un intranet, sans autorisation écrite préalable. Une autorisation peut

être demandée à l’ISO à l’adresse ci-après ou au comité membre de l’ISO dans le pays du demandeur.

ISO copyright office
Case postale 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Genève
Tél.: [phone]
E-mail: [e-mail]
Web: www.iso.org
Publié en Suisse
© ISO 2021 – Tous droits réservés
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ISO/FDIS 683-3:2021(F)
Sommaire Page

Avant-propos ...............................................................................................................................................................................................................................v

1 Domaine d’application ................................................................................................................................................................................... 1

2 Références normatives ..................................................................................................................................................................................1

3 Termes et définitions ...................................................................................................................................................................................... 2

4 Classification et désignation ...................................................................................................................................................................3

4.1 Classification ............................................................................................................................................................................................ 3

4.2 Désignation ................................................................................................................................................................................................ 3

5 Informations à fournir par l'acheteur ........................................................................................................................................... 3

5.1 Informations obligatoires ............................................................................................................................................................. 3

5.2 Options et/ou exigences supplémentaires ou particulières .......................................................................... 3

5.3 Exemple de commande .................................................................................................................................................................... 4

6 Procédé d'élaboration ....................................................................................................................................................................................4

6.1 Généralités ................................................................................................................................................................................................. 4

6.2 Désoxydation............................................................................................................................................................................................ 4

6.3 État de traitement thermique et état de surface à la livraison .................................................................... 4

6.3.1 État normal de livraison .............................................................................................................................................. 4

6.3.2 État particulier de traitement thermique .................................................................................................... 4

6.3.3 État de surface particulier ......................................................................................................................................... 4

6.4 Traçabilité de la coulée .................................................................................................................................................................... 4

7 Exigences ...................................................................................................................................................................................................................... 5

7.1 Composition chimique, dureté et trempabilité .......................................................................................................... 5

7.1.1 Généralités ............................................................................................................................................................................... 5

7.1.2 Trempabilité ........................................................................................................................................................................... 5

7.1.3 Composition chimique ................................................................................................................................................... 5

7.2 Usinabilité ................................................................................................................................................................................................... 5

7.3 Aptitude au cisaillage à froid ..................................................................................................................................................... 5

7.4 Taille de grain .......................................................................................................................................................................................... 6

7.5 Inclusions non métalliques .......................................................................................................................................................... 6

7.5.1 Inclusions microscopiques ........................................................................................................................................ 6

7.5.2 Inclusions macroscopiques ....................................................................................................................................... 6

7.6 Santé interne ............................................................................................................................................................................................ 6

7.7 État de surface ........................................................................................................................................................................................ 6

7.8 Forme, dimensions et tolérances ............................................................................................................................................ 7

8 Contrôle ......................................................................................................................................................................................................................... 7

8.1 Procédures d'essai et types de documents ................................................................................................................... 7

8.2 Fréquence des essais ......................................................................................................................................................................... 8

8.3 Essais à réaliser pour un contrôle spécifique ............................................................................................................. 8

8.3.1 Généralités ............................................................................................................................................................................... 8

8.3.2 Contrôles visuels et dimensionnels ................................................................................................................... 8

9 Méthodes d'essai .................................................................................................................................................................................................. 8

9.1 Analyse chimique ................................................................................................................................................................................. 8

9.2 Essais de dureté et de trempabilité...................................................................................................................................... 8

9.2.1 Vérifications de la dureté ............................................................................................................................................ 8

9.2.2 Vérifications de la trempabilité ............................................................................................................................. 8

9.3 Contre-essais ........................................................................................................................................... ................................................. 8

10 Marquage ..................................................................................................................................................................................................................... 9

Annexe A (normative) Exigences supplémentaires ou particulières ............................................................................30

Annexe B (informative) Comparaison des désignations d'aciers indiquées dans le présent

document avec d'autres nuances d'acier présentées dans d'autres systèmes de

désignation .............................................................................................................................................................................................................32

iii
© ISO 2021 – Tous droits réservés
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ISO/FDIS 683-3:2021(F)

Annexe C (informative) Classification des nuances d'acier selon la résistance à la traction

minimale en fonction du diamètre après trempe et revenu à 200 °C .......................................................34

Bibliographie ...........................................................................................................................................................................................................................35

© ISO 2021 – Tous droits réservés
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ISO/FDIS 683-3:2021(F)
Avant-propos

L'ISO (Organisation internationale de normalisation) est une fédération mondiale d'organismes

nationaux de normalisation (comités membres de l'ISO). L'élaboration des Normes internationales est

en général confiée aux comités techniques de l'ISO. Chaque comité membre intéressé par une étude

a le droit de faire partie du comité technique créé à cet effet. Les organisations internationales,

gouvernementales et non gouvernementales, en liaison avec l'ISO participent également aux travaux.

L'ISO collabore étroitement avec la Commission électrotechnique internationale (IEC) en ce qui

concerne la normalisation électrotechnique.

Les procédures utilisées pour élaborer le présent document et celles destinées à sa mise à jour sont

décrites dans les Directives ISO/IEC, Partie 1. Il convient, en particulier de prendre note des différents

critères d'approbation requis pour les différents types de documents ISO. Le présent document

a été rédigé conformément aux règles de rédaction données dans les Directives ISO/IEC, Partie 2

(voir www.iso.org/directives).

L'attention est attirée sur le fait que certains des éléments du présent document peuvent faire l'objet de

droits de propriété intellectuelle ou de droits analogues. L'ISO ne saurait être tenue pour responsable

de ne pas avoir identifié de tels droits de propriété et averti de leur existence. Les détails concernant

les références aux droits de propriété intellectuelle ou autres droits analogues identifiés lors de

l'élaboration du document sont indiqués dans l'Introduction et/ou dans la liste des déclarations de

brevets reçues par l'ISO (voir www.iso.org/brevets).

Les appellations commerciales éventuellement mentionnées dans le présent document sont données

pour information, par souci de commodité, à l’intention des utilisateurs et ne sauraient constituer un

engagement.

Pour une explication de la nature volontaire des normes, la signification des termes et expressions

spécifiques de l'ISO liés à l'évaluation de la conformité, ou pour toute information au sujet de l'adhésion

de l'ISO aux principes de l’Organisation mondiale du commerce (OMC) concernant les obstacles

techniques au commerce (OTC), voir le lien suivant: www.iso.org/iso/fr/avant-propos.html.

Le présent document a été élaboré par le comité technique l’ISO/TC 17, Acier, sous-comité SC 4, Aciers

pour traitements thermiques et aciers alliés.

Cette quatrième édition annule et remplace la troisième édition (ISO 683-3:2019), qui a fait l’objet d’une

révision technique. Les principales modifications par rapport à l’édition précédente sont les suivantes:

— les nuances d'acier 23MnCrMo5-5-4 et 17NiCrMoS6-4 ont été ajoutées;

— la teneur inférieure de silicium dans le Tableau 3 a été supprimée et remplacée par une nouvelle

option dans l'Article A.4;

Une liste de toutes les parties de la série ISO 683 se trouve sur le site Web de l’ISO.

Tout retour d'information ou toute question sur ce document doit être adressé à l'organisme national

de normalisation de l'utilisateur. La liste complète de ces organismes se trouve à l'adresse suivante:

www.iso.org/members.html.
© ISO 2021 – Tous droits réservés
---------------------- Page: 5 ----------------------
PROJET FINAL DE NORME INTERNATIONALE ISO/FDIS 683-3:2021(F)
Aciers pour traitement thermique, aciers alliés et aciers
pour décolletage —
Partie 3:
Aciers pour cémentation
1 Domaine d’application
Le présent document spécifie les conditions techniques de livraison des

— demi-produits formés à chaud, comme par exemple les blooms, billettes et brames (voir NOTE 1);

— barres (voir NOTE 1),
— fils machine,
— produits plats finis, et
— pièces forgées par martelage ou estampage (voir NOTE 1)

fabriqués à partir d'aciers alliés ou non alliés pour cémentation énumérés dans le Tableau 3 et livrés

dans l'un des états de traitement thermique donnés pour les différents types de produits dans le

Tableau 1 et dans l'un des états de surface donnés dans le Tableau 2.

Les aciers sont en général destinés à la fabrication de pièces mécaniques cémentées.

NOTE 1 Les produits semi-finis forgés par martelage (blooms, billettes, brames, etc.), les anneaux laminés

sans soudure et les barres forgées par martelage figurent parmi les produits semi-finis ou les barres, et non sous

l'appellation «pièces forgées par martelage ou estampage».

NOTE 2 Pour les Normes internationales relatives aux aciers qui sont conformes aux exigences de composition

chimique du Tableau 3, mais fournis sous d’autres formes de produits ou dans des états de traitement autres

que ceux indiqués ci-dessus, ou qui sont destinés à des applications spéciales, ainsi que pour d'autres Normes

internationales analogues, voir la Bibliographie.
2 Références normatives

Les documents suivants sont cités dans le texte de sorte qu’ils constituent, pour tout ou partie de leur

contenu, des exigences du présent document. Pour les références datées, seule l’édition citée s’applique.

Pour les références non datées, la dernière édition du document de référence s'applique (y compris les

éventuels amendements)

ISO 377, Acier et produits en acier — Position et préparation des échantillons et éprouvettes pour essais

mécaniques

ISO 404, Aciers et produits sidérurgiques — Conditions générales techniques de livraison

ISO 642:1999, Acier — Essai de trempabilité par trempe en bout (essai Jominy)
ISO 643, Aciers — Détermination micrographique de la grosseur de grain apparente
ISO 4885, Matériaux ferreux — Traitements thermiques — Vocabulaire

ISO 4948-1, Aciers — Classification — Partie 1: Classification en aciers alliés et en aciers non alliés basée

sur la composition chimique
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ISO 4948-2, Aciers — Classification — Partie 2: Classification des aciers alliés et aciers non alliés en fonction

des principales classes de qualité et des caractéristiques principales de propriétés ou d'application

ISO/TS 4949, Désignations des aciers fondées sur des lettres symboles

ISO 4967, Aciers — Détermination de la teneur en inclusions non métalliques — Méthode micrographique à

l'aide d'images types

ISO 6506-1, Matériaux métalliques — Essai de dureté Brinell — Partie 1: Méthode d'essai

ISO 6508-1, Matériaux métalliques — Essai de dureté Rockwell — Partie 1: Méthode d'essai

ISO 6929, Produits en acier — Vocabulaire

ISO 7788, Acier — État de surface des tôles et larges-plats laminés à chaud — Conditions de livraison

ISO 9443, Classes de qualité de surface des barres et fils-machine laminés à chaud

ISO/TR 9769, Aciers et fontes — Vue d'ensemble des méthodes d'analyse disponibles

ISO 10474, Aciers et produits sidérurgiques — Documents de contrôle

ISO 14284, Fontes et aciers — Prélèvement et préparation des échantillons pour la détermination de la

composition chimique
3 Termes et définitions

Pour les besoins du présent document, les termes et définitions de l'ISO 377, l'ISO 4885, l'ISO 4948-1,

l'ISO 4948-2, l'ISO 6929, ISO 14284 ainsi que les suivants s'appliquent.

NOTE Pour les variantes de ces termes et définitions, voir la NOTE 1 du Domaine d'application et la note de

bas de tableau b du Tableau 2.

L’ISO et l’IEC maintiennent des bases de données terminologiques pour utilisation dans le domaine de la

normalisation aux adresses suivantes:

— ISO Online browsing platform: disponible à l’adresse https:// www .iso .org/ obp

— IEC Electropedia: disponible à l’adresse https:// www .electropedia .org/
3.1
acier de cémentation

acier ayant une teneur en carbone relativement faible, destiné à un traitement de cémentation ou de

carbonitruration sur sa surface et suivi d'une trempe

Note 1 à l'article: Après trempe, ces aciers se caractérisent par une dureté élevée dans la zone de surface et une

bonne résistance à l’usure, alors que le cœur du matériau présente une grande ténacité.

Note 2 à l'article: De plus, d’autres possibilités de traitement thermique des aciers de cémentation sont, par

exemple, la nitrocarburation et la nitruration.
3.2
acier non allié
tel que défini dans l'ISO 4948-1
3.3
acier allié
tel que défini dans l'ISO 4948-1
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4 Classification et désignation
4.1 Classification

La classification des nuances d'acier appropriées est appliquée conformément à l'ISO 4948-1 et à

l'ISO 4948-2. Les nuances d'acier C10E, C10R, C15E, C15R, C16E, C16R et 22Mn6 sont des aciers spéciaux

non alliés. Toutes les autres nuances d'acier concernées par le présent document sont des aciers spéciaux

alliés.
4.2 Désignation

Pour les nuances d'acier concernées par le présent document, les noms des aciers tels qu'ils sont donnés

dans les tableaux correspondants doivent être attribués conformément à l'ISO/TS 4949.

Une comparaison entre les désignations d'aciers indiquées dans le présent document avec celles

présentées dans d'autres systèmes de désignation est donnée dans l’Annexe B.
5 Informations à fournir par l'acheteur
5.1 Informations obligatoires

Les informations suivantes doivent être fournies par l'acheteur lors de l'appel d'offres et de la

commande:
a) la quantité à livrer;

b) la désignation de la forme du produit (brame, bloom, billette, barre ronde, carrée ou hexagonale,

fils machine, larges plats, feuillard, tôle, bande, pièce forgée, etc.);

c) soit la désignation de la ou des normes dimensionnelles et les dimensions et les tolérances choisies

à partir de celles-ci (voir 7.8), soit, par exemple, dans le cas de pièces forgées par estampage, la

désignation de l'étirage ou de tout autre document concernant les dimensions et les tolérances

requises pour le produit;
d) la référence au présent document, c'est-à-dire, ISO 683-3;
e) la désignation du type d'acier donnée dans le Tableau 3;

f) la désignation normalisée correspondant au relevé de contrôle 2.2 ou, sur demande, à tout autre

document de contrôle conforme à l'ISO 10474 ou une norme équivalente, par exemple, EN 10204 ou

JIS G 0415.
5.2 Options et/ou exigences supplémentaires ou particulières

Un certain nombre d'options sont spécifiées dans le présent document et sont répertoriées ci-dessous.

Si l'acheteur ne précise pas vouloir mettre en œuvre l'une de ces options, les produits sont fournis

conformément aux spécifications de base du présent document (voir 5.1):

a) si un état de traitement thermique autre que l'état non traité est requis, le symbole pour cet autre

état (voir Tableau 1, colonne 2);

b) si un état de surface autre que l'état «écroui à chaud» ou une qualité particulière de surface est

requis, l'état de surface (voir Tableau 2) et la qualité de surface (voir 7.7.3);

c) toute exigence relative aux bandes restreintes de dispersion de trempabilité pour les aciers alliés

(symboles +HH, + HL, voir 7.1.1, Tableau 6 et Figure 1);

d) si des exigences supplémentaires doivent être respectées selon le symbole et, le cas échéant, les

détails de cette exigence supplémentaire conformes à l’Annexe A;
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e) toute exigence relative à la vérification de la teneur en inclusions non métalliques (voir 7.5);

f) la vérification de la trempabilité et, s’il y a accord, les informations relatives au calcul de la

trempabilité (voir 9.2.2);

g) toute exigence relative à la possibilité de soumettre les barres et les fils machine à l'étirage à froid

(voir 7.7.4);

h) toute exigence relative à l'élimination des défauts superficiels (voir 7.7.5).

5.3 Exemple de commande

EXEMPLE 50 barres rondes laminées à chaud selon l'ISO 1035-1 avec un diamètre nominal de 40 mm et

une longueur nominale de 8 000 mm avec une tolérance de diamètre de classe S et une tolérance de longueur de

classe L2 selon l'ISO 1035-4, fabriqués en nuance d'acier ISO 683-3, 20MnCr5 (voir Tableau 3), suivant la condition

de traitement thermique adoucie (+A), une surface grenaillée (+BC) (voir Tableau 2), une analyse sur produit/

option A.3 avec un certificat de réception 3.1 conformément à l'ISO 10474.
50 barres rondes ISO 1035 – 40,0S × 8 000L2
ISO 683-3 – 20MnCr5+A+BC, Option A.3
ISO 10474 – 3.1
6 Procédé d'élaboration
6.1 Généralités

Le procédé d'élaboration de l'acier et des produits est laissé au choix du fabricant, sous réserve des

limites données par les exigences indiquées en 6.2 et 6.4.

Pour le degré minimal de réduction ou le degré minimal de déformation de l'épaisseur sur les produits

laminés et forgés, voir Article A.5.
6.2 Désoxydation
Tous les aciers doivent être complètement désoxydés.
6.3 État de traitement thermique et état de surface à la livraison
6.3.1 État normal de livraison

Sauf accord contraire lors de l'appel d'offres et de la commande, les produits doivent être livrés à l'état

non traité, c’est-à-dire écroui à chaud.
6.3.2 État particulier de traitement thermique

Par accord au moment de l'appel d'offres et de la commande, les produits doivent être livrés dans l'un

des états de traitement thermique donnés dans le Tableau 1, lignes 3 à 8.
6.3.3 État de surface particulier

Par accord au moment de l'appel d'offres et de la commande, les produits doivent être livrés dans l'un

des états de surface particuliers donnés dans le Tableau 2, lignes 3 à 6.
6.4 Traçabilité de la coulée
Les produits doivent pouvoir être retracés jusqu'à la coulée, voir Article 10.
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7 Exigences
7.1 Composition chimique, dureté et trempabilité
7.1.1 Généralités

Le Tableau 1 fournit un relevé des combinaisons des états habituels de traitement thermiques à la

livraison, des formes de produit et des exigences, spécifiés dans les Tableaux 3 à 7 (composition

chimique, trempabilité, dureté maximale et fourchette de dureté).

Dans des cas particuliers, des variations ou des ajouts à ces exigences techniques de livraison peuvent

faire l'objet d'un accord au moment de la demande et de la commande (voir 5.2 et Annexe A).

En complément de ce document, les exigences techniques générales de livraison de la norme

ISO 404 s'appliquent.
7.1.2 Trempabilité

Sauf accord contraire pour les aciers alliés, les exigences de trempabilité données dans le Tableau 5

s'appliquent. En cas d'accord au moment de l'appel d'offres et de la commande, des aciers alliés avec les

bandes restreintes de dispersion de trempabilité données dans le Tableau 6 ou à la Figure 1 doivent être

fournis.

Une classification des nuances d'acier selon la résistance à la traction minimale en fonction du diamètre

après trempe et revenu est donnée en Annexe C.
7.1.3 Composition chimique

La composition chimique déterminée par analyse de coulée doit être conforme aux valeurs du Tableau 3.

Les écarts admissibles entre les valeurs limites de l'analyse de coulée et les valeurs de l'analyse sur

produit sont données dans le Tableau 4.

L'analyse sur produit doit être réalisée lorsque cela est spécifié au moment de l'appel d'offres et de la

commande (voir Article A.3).
7.2 Usinabilité

Tous les aciers sont usinables à l’état «adouci», «traité pour une fourchette de dureté», «traité pour une

structure ferrite/perlite» et «normalisé».

Réduire la teneur en silicium peut avoir une influence négative sur l'usinabilité. Pour des informations

sur la teneur minimale de silicium, se référer à l'Article A.4.

Lorsqu'une usinabilité plus importante est nécessaire, il convient de commander des nuances avec

une gamme de soufre spécifiée et/ou avec un traitement spécifique pour améliorer l’usinabilité (voir

également le Tableau 3, note de bas de tableau b).
7.3 Aptitude au cisaillage à froid

7.3.1 Dans des conditions de cisaillage appropriées (pas de crête de contraintes localisées,

préchauffage, utilisation de lames de profil adapté à celui du produit, etc.), tous les aciers sont cisaillables

à froid à l'état «adouci».

7.3.2 Dans des conditions convenables, les nuances d'acier 28Cr4, 28CrS4, 20MnCr5, 20MnCrS5,

24CrMo4, 24CrMoS4, 22CrMoS3-5, 20MoCr4, 20MoCrS4, 16NiCr4, 16NiCrS4, 18NiCr5-4, 17CrNi6-6,

15NiCr13, 17NiCrMo6-4, 23MnCrMo5-5-4 et 18CrNiMo7-6, sont également cisaillables à froid, si elles

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sont livrées à l'état «traité pour une meilleure aptitude au cisaillage» en respectant les exigences de

dureté données au Tableau 7.

7.3.3 Dans des conditions convenables, les aciers non alliés et aciers 17Cr3, 17CrS3, 20Cr4, 20CrS4,

16MnCr5, 16MnCrS5, 16MnCrB5, 18CrMo4, 18CrMoS4, 20NiCrMo2-2 et 20NiCrMoS2-2 sont cisaillables à

froid, s'ils sont livrés à l'état non traité.
7.4 Taille de grain

Sauf accord contraire au moment de l'appel d'offres et de la commande, l'acier doit présenter une

structure à grains fins d'une grosseur de grain d'austénite de 5 ou plus fin lors de l'essai réalisé

conformément à l'ISO 643. Pour la vérification, voir Article A.1.
7.5 Inclusions non métalliques
7.5.1 Inclusions microscopiques

Les aciers spéciaux doivent avoir un certain degré de pureté, toutefois, la vérification de la teneur en

inclusions non métalliques doit faire l'objet d'un accord spécial. S'il y a un tel accord au moment de

l'appel d'offres et de la commande, la teneur en inclusions microscopiques non métalliques doit être

déterminée conformément à la procédure convenue et dans les limites convenues selon l’ISO 4967 ou

une autre norme équivalente.

Pour les nuances à faible teneur en soufre spécifiée, il convient que l’accord n’inclue pas les sulfures.

7.5.2 Inclusions macroscopiques

Cette exigence est applicable à la vérification de la teneur inclusionnaire macroscopique dans des aciers

spéciaux. Si une vérification est demandée, la méthode et les limites d’acceptations doivent faire l’objet

d’un accord au moment de l’appel d’offres et de la commande.
7.6 Santé interne
Le cas échéant,
...