ISO/FDIS 8458-3

Steel wire for mechanical springs — Part 3: Oil-hardened and tempered wire

ISO 8458-3 specifies requirements for oil-hardened and tempered carbon and low alloy steel wire, for the manufacture of mechanical springs for static duty and dynamic duty applications, complying with the general requirements of ISO 8458-1.

Fils en acier pour ressorts mécaniques — Partie 3: Fils trempés à l'huile et revenus

L'ISO 8458-3:2002 spécifie les exigences pour le fil en acier au carbone et faiblement allié trempé à l'huile et revenu, destiné à la fabrication de ressorts mécaniques pour applications statiques et dynamiques, satisfaisant aux exigences générales de l'ISO 8458-1.

General Information

• Status: Not Published
• ICS: 77.140.25 - Spring steels
• Technical Committee: ISO/TC 17/SC 17 - Steel wire rod and wire products
• Drafting Committee: ISO/TC 17/SC 17 - Steel wire rod and wire products
• Current Stage: 5020 - FDIS ballot initiated: 2 months. Proof sent to secretariat
• Start Date: 28-Oct-2025
• Completion Date: 28-Oct-2025

Relations

• Revises: ISO 8458-3:2002 - Steel wire for mechanical springs — Part 3: Oil-hardened and tempered wire
• Effective Date: 28-Jun-2025

Standards Content (Sample)

FINAL DRAFT
International
Standard
ISO/TC 17/SC 17
Steel wire for mechanical springs —
Secretariat: SAC
Part 3:
Voting begins on:
Oil-hardened and tempered wire
Voting terminates on:
Fils en acier pour ressorts mécaniques —
Partie 3: Fils trempés à l'huile et revenus
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
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
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.
Reference number
FINAL DRAFT
International
Standard
ISO/TC 17/SC 17
Steel wire for mechanical springs —
Secretariat: SAC
Part 3:
Voting begins on:
Oil-hardened and tempered wire
Voting terminates on:
Fils en acier pour ressorts mécaniques —
Partie 3: Fils trempés à l'huile et revenus
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.
© ISO 2025
IN ADDITION TO THEIR EVALUATION AS
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
LOGICAL, COMMERCIAL AND USER PURPOSES, DRAFT
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
INTERNATIONAL STANDARDS MAY ON OCCASION HAVE
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
TO BE CONSIDERED IN THE LIGHT OF THEIR POTENTIAL
or ISO’s member body in the country of the requester.
TO BECOME STAN DARDS TO WHICH REFERENCE MAY BE
MADE IN NATIONAL REGULATIONS.
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 Reference number
ii
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Classification and designation . 1
5 Dimensional tolerances . 2
6 Requirements . 2
6.1 Chemical composition .2
6.2 Surface quality .3
6.3 Non-metallic inclusions .3
6.4 Mechanical properties .3
6.5 Technological properties .3
6.5.1 Wrapping test .3
6.5.2 Torsion test .5
6.5.3 Bend test .6
6.5.4 Coiling test .6
7 Test methods and other requirements . 6

iii
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 document 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).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
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 17, Steel wire rod
and wire products.
This third edition cancels and replaces the second edition (ISO 8458-3:2002), of which it constitutes a minor
revision.
The changes are as follows:
— the normative references have been updated;
— the structure of the document has been updated in accordance with the latest ISO/IEC Directives, Part 2.
A list of all parts in the ISO 8458 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.

iv
FINAL DRAFT International Standard ISO/FDIS 8458-3:2025(en)
Steel wire for mechanical springs —
Part 3:
Oil-hardened and tempered wire
1 Scope
This document specifies requirements for oil-hardened and tempered carbon and low alloy steel wire, for
the manufacture of mechanical springs for static duty and dynamic duty applications, in accordance with
the general requirements of ISO 8458-1.
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 4967, Steel — Determination of content of non-metallic inclusions — Micrographic method using standard
diagrams
ISO 8458-1, Steel wire for mechanical springs — Part 1: General requirements
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8458-1 apply.
ISO and IEC maintain terminology 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/
4 Classification and designation
The various spring wire grades and the relevant diameters are shown in Table 1.
Table 1 — Spring wire grades and diameter ranges
Tensile strength Static Medium fatigue High fatigue
Low tensile strength FDC TDC VDC
Medium tensile strength FDCrV(A.B) TDCrV(A.B) VDCrV(A.B)
High tensile strength FDSiCr TDSiCr VDSiCr
Diameter range (mm) 0,50 to 17,00 0,50 to 10,00 0,50 to 10,00
FD grade is intended for static applications, required for normal springs.
TD grade is intended for medium fatigue levels.
VD grade is intended for use under severe dynamic duty such as for valve springs.

5 Dimensional tolerances
The permissible dimensional tolerances on wire in coils and cut lengths shall be in accordance with those
specified in ISO 8458-1.
When the required tolerance level is different from those mentioned above, it shall be agreed at the time of
ordering.
6 Requirements
6.1 Chemical composition
The steel is characterized by the heat analysis, which shall be in accordance with the values listed in Table 2.
The permissible deviation of the product analysis from the heat analysis shall be in accordance with Table 3.
Table 2 — Chemical composition, mass fraction
Values in percent
Grade C Si Mn P S Cr V Cu max.
max. max.
FDC 0,60 to 0,75 0,10 to 0,35 0,50 to 1,20 0,030 0,030 — — 0,20
TDC 0,60 to 0,75 0,10 to 0,35 0,50 to 1,20 0,020 0,025 — — 0,12
VDC 0,60 to 0,75 0,15 to 0,30 0,50 to 1,00 0,020 0,025 — — 0,12
FDCrV-A 0,030 0,03
...

Style Definition
ISO/TC 17/SC 17 N 1380 .
Formatted: Right: 1.5 cm, Bottom: 1 cm, Gutter: 0 cm,
ISO/FDIS 8458-3(en) Section start: New page, Header distance from edge:
1.27 cm, Footer distance from edge: 1.27 cm
ISO/TC 17/SC 17
Formatted: French (Switzerland)
Formatted: zzCover large, Left
Date: 2025-09-15
Secretariat: SAC
Formatted
...
Formatted: zzCover, Left
Date: 2025-10-13
Steel wire for mechanical springs —
Formatted: Regular
Part 3:
Formatted: Cover Title_A2
Oil-hardened and tempered wire
Fils en acier pour ressorts mécaniques —
Partie 3: Fils trempés à l'huile et revenus
Formatted: Cover Title_B, Space Before: 0 pt

Formatted: Footer, Left, Space Before: 0 pt, After: 0
pt, Line spacing: single
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ISO #####-#:####(X)
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FDIS stage
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border), Left: (No border), Right: (No border)

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2 © ISO #### – All rights reserved

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Before: 0 pt, No page break before, Adjust space
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication
between Latin and Asian text, Adjust space between
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
Asian text and numbers, Border: Top: (No border), Left:
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
(No border), Right: (No border)
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: + 41 22 749 01 11
Formatted: French (Switzerland)
EmailE-mail: [e-mail]
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Website: www.iso.orgwww.iso.org
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Published in Switzerland
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iii
Contents Formatted: Space Before: 48 pt
Foreword . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Classification and designation. 1
5 Dimensional tolerances . 2
6 Requirements . 2
7 Test methods and other requirements . 7

Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Classification and designation. 2
5 Dimensional tolerances . 2
6 Requirements . 2
6.1 Chemical composition . 2
6.2 Surface quality . 3
6.3 Non-metallic inclusions . 4
6.4 Mechanical properties . 4
6.5 Technological properties . 4
6.5.1 Wrapping test . 4
6.5.2 Torsion test . 8
6.5.3 Bend test . 8
6.5.4 Coiling test . 9
7 Test methods and other requirements . 9

iv
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
Formatted: Font color: Auto
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types of
Formatted: Font color: Auto
ISO documentsdocument should be noted. This document was drafted in accordance with the editorial rules
Formatted: Font color: Auto
of the ISO/IEC Directives, Part 2 (see www.iso.org/directives 2 (see www.iso.org/directives).
Formatted: Font color: Auto
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
Formatted: Font color: Auto, English (United Kingdom)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent rights
in respect thereof. As of the date of publication of this document, ISO had not received notice of (a) patent(s)
which may be required to implement this document. However, implementers are cautioned that this may not
represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents.www.iso.org/patents. ISO shall not be held responsible for identifying any or all such
Formatted: Font color: Auto, English (United Kingdom)
patent rights.
Any trade name used in this document is information given for the convenience of users and does not
Formatted: Font color: Auto
constitute an endorsement.
Formatted: Font color: Auto
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.htmlwww.iso.org/iso/foreword.html.
Formatted: Font color: Auto
This document was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 17, Steel wire rod
Formatted: Font: Not Italic
and wire products.
Formatted: Font: Not Italic
Formatted: Font: Not Italic
This third edition cancels and replaces the second edition (ISO 8458-3:2002), of which has been editorially
revisedit constitutes a minor revision.
The main changes are as follows:
Formatted: Font: Cambria
— — the normative references have been updated ;
Formatted: List Continue 1
— the structure of the document has been updated in accordance with the latest ISO/IEC
Formatted: Font: Not Italic
Directives,
— Part 2.
Formatted: List Continue 1, Indent: Left: 0 cm
Formatted: Font: Not Italic
ISO 8458 consistsA list of the followingall parts, under in the ISO 8458 series can be found on the general title
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.
v
Formatted: Font: 16 pt, English (United Kingdom)
Steel wire for mechanical springs: —
Formatted: Main Title 1
— Part 1: General requirements
Formatted: Font: 16 pt, English (United Kingdom)

— Part 2: Patented cold-drawn non-alloy steel wire

Formatted: Main Title 2
— Part 3:
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Oil-hardened and tempered wire
Formatted: Font: Not Italic, English (United Kingdom)
vi © ISO 2025 – All rights reserved

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Formatted: HeaderCentered
Formatted: Right: 1.5 cm, Bottom: 1 cm, Gutter: 0 cm,
Steel wire for mechanical springs — Part 3: Oil-hardened and
Section start: New page, Header distance from edge:
1.27 cm, Footer distance from edge: 0.5 cm
tempered wire
1 Scope
This document specifies requirements for oil-hardened and tempered carbon and low alloy steel wire, for the
Formatted: Body Text
manufacture of mechanical springs for static duty and dynamic duty applications, complyingin accordance
Formatted: Font: 11 pt, Not Bold
with the general requirements of ISO 8458-1.
Formatted: Font color: Auto
2 Normative references
Formatted: Font: 11 pt
Formatted: Font: Italic
The following documents are referred to in the text in such a way that some or all of their content constitutes
Formatted: Font color: Auto
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.
Formatted: Font color: Auto
Formatted: Font color: Auto
ISO 4967, Steel — Determination of content of non-metallic inclusions — Micrographic method using standard
Formatted: Font color: Auto
diagrams
Formatted
...
ISO 8458-1, Steel wire for mechanical springs — Part 1: General requirements
Formatted: No underline, Font color: Auto
3 Terms and definitions Field Code Changed
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NoFor the purposes of this document, the terms and definitions are listedgiven in this documentISO 8458-1
Field Code Changed
apply.
Formatted: No underline, Font color: Auto
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
Formatted: No page break before
Formatted: Body Text
— ISO Online browsing platform: available at https://www.iso.org/obp
Formatted: Indent: Left: 0 cm
— IEC Electropedia: available at https://www.electropedia.org/
Formatted: Font: Not Bold
Formatted: Table header
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4 Classification and designation
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The various spring wire grades and the relevant diameters are shown in Table 1.0. Formatted: Font: Not Bold
Formatted: Table body
Table 1Table 1 — Spring wire grades and diameter ranges
Formatted: Table body
Tensile strength Static Medium fatigue High fatigue
Formatted Table
Low tensile strength FDC TDC VDC
Formatted: Table body
Medium tensile strength FDCrV(A.B) TDCrV(A.B) VDCrV(A.B)
Formatted: Table body
High tensile strength FDSiCr TDSiCr VDSiCr
Formatted: Font: 9 pt
Diameter range (mm) 0,50 to 17,00 0,50 to 10,00 0,50 to 10,00
Formatted: Table footer
FD grade is intended for static applications, required for normal springs.
Formatted Table
TD grade is intended for medium fatigue levels.
Formatted: Font: 10 pt
VD grade is intended for use under severe dynamic duty such as for valve springs.
Formatted: Font: 10 pt
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© ISO 2025 – All rights reserved
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5 Dimensional tolerances
Formatted
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The permissible dimensional tolerances on wire in coils and cut lengths shall be in accordance with those .
specified in ISO 8458-1.
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...
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When the required tolerance level is different from those mentioned above, it shall be agreed at the time of
Formatted
ordering.
...
Formatted
...
6 Requirements
Formatted
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6.1 Chemical composition Formatted
...
Formatted
...
The steel is characterized by the heat analysis, which shall be in accordance with the values listed in Table 2.0.
Formatted
...
The permissible deviation of the product analysis from the heat analysis shall be in accordance with Table 3.0.
Formatted
...
Table 2Table 2 — Chemical composition, mass fraction
Formatted
...
Values in percent
Formatted
...
Grade C Si Mn P S Cr V Cu
Formatted
...
max. max. max.
Formatted
...
FDC 0,60 to 0,10 to 0,50 to 0,030 0,030 — 0,20
—
Formatted
...
0,75 0,35 1,20
Formatted
...
TDC 0,60 to 0,10 to 0,50 to 0,020 0,025 — 0,12
—
0,75 0,35 1,20
Formatted
...
VDC 0,60 to 0,15 to 0,50 to 0,020 0,025 — 0,12 Formatted
...
—
0,75 0,30 1,00
Formatted
...
FDCrV-A 0,030 0,030 0,20
Formatted
...
0,47 to 0,10 to 0,60 to 0,80 to 0,15 to
TDCrV-A 0,025 0,025 0,12
0,55 0,40 1,20 1,10 0,25
Formatted
...
VDCrV-A 0,025 0,025 0,12
Formatted
...
FDCrV-B 0,030 0,030 0,20
0,62 to 0,15 to 0,50 to 0,40 to 0,15 to Formatted
...
TDCrV-B 0,025 0,025 0,12
0,72 0,30 0,90 0,60 0,25
Formatted
VDCrV-B 0,025 0,025 0,12 .
Formatted
...
FDSiCr 0,030 0,030 0,20
0,50 to 1,20 to 0,50 to 0,50 to
TDSiCr 0,025 0,025 — 0,12 Formatted
...
0,60 1,60 0,90 0,80
VDSiCr 0,025 0,025 0,12
Formatted
...
Formatted
...
Formatted
...
Table 3Table 3 — Permissible deviation of the product analysis from the limiting values for the heat
Formatted
analysis
...
Formatted Table
...
Chemical element Wire grade Permissible deviation, % by mass
Formatted
...
C All ± 0,03
Formatted
...
SiCr  ±0,05
Formatted
Si
...
other grades
 ±0,03
Formatted
...
Mn All  ±0,04
Formatted
...
P All  +0,005
Formatted
...
S All
 +0,005
Formatted
...
Formatted
...
2 © ISO 2025 – All rights reserved
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Chemical element Wire grade Permissible deviation, % by mass
Formatted
...
Cu All
 +0,02
Formatted
...
Cr All  ±0,05
Formatted
...
V All
 ±0,02
Formatted
...
Formatted
...
Formatted
6.2 Surface quality
...
Formatted
...
6.2.1 6.2.1 The surface of the wire shall be smooth. The permissible maximum depth of surface
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discontinuities measured on samples as defined in ISO 8458-1 shall be in accordance with Table 4.0. .
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Table 44 — Permissible maximum depth of surface discontinuities
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Dimensions in millimetres
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VD TD FD
Formatted
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Wire diameter, d
a
Class 1 Class 2
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...
b b
2,00 ≤ d ≤ 6,00 0,005d 0,008d 0,013d 0,01d 01d
Formatted
...
6,00 < d ≤ 10,00 0,007d 0,01d 0,013d 0,014d
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...
a
Only for SiCr grades.
Formatted
...
b
For SiCr grades, 1,4 %.
Formatted
...
Formatted
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6.2.2 6.2.2 Eddy current inline testing shall be performed for VD grades and is optional for TD grades. The
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...
method of testing and the evaluation of test results shall be agreed upon between the parties. Eddy current
testing is normally applied for sizes 2,50 mm to 6,00 mm.
Formatted
...
Formatted
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6.2.3 6.2.3 The cross-section of wire of VD and TD shall be free from complete decarburization. The
permissible maximum average
...