ISO 4991:2015

Steel castings for pressure purposes

ISO 4991:2015 covers steel castings for pressure containing parts. It includes materials which are used for the manufacture of components subject to pressure vessel codes and components not subject to codes. This International Standard relates to castings manufactured from unalloyed and alloyed steel grades (characterized by their chemical composition, Table 1, and mechanical properties, Tables 2, 3, 4 and 5). NOTE Annex D gives information on ISO grade designation and available UNS numbers which are similar to the ISO grade designation.

Pièces moulées en acier pour service sous pression

General Information

• Status: Published
• Publication Date: 13-Dec-2015
• ICS: 77.140.30 - Steels for pressure purposes
• ICS: 77.140.80 - Iron and steel castings
• Technical Committee: ISO/TC 17/SC 11 - Steel castings
• Drafting Committee: ISO/TC 17/SC 11 - Steel castings
• Current Stage: 9092 - International Standard to be revised
• Completion Date: 12-Jan-2022

Relations

• Consolidated By: ISO 16140-6:2019 - Microbiology of the food chain — Method validation — Part 6: Protocol for the validation of alternative (proprietary) methods for microbiological confirmation and typing procedures
• Effective Date: 06-Jun-2022

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 4991
Third edition
2015-12-15
Steel castings for pressure purposes
Pièces moulées en acier pour service sous pression
Reference number
ISO 4991:2015(E)
©
ISO 2015

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ISO 4991:2015(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, 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.
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Tel. [phone]
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ii © ISO 2015 – All rights reserved

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ISO 4991:2015(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Information to be supplied by the purchaser. 1
5 Heat treatment . 1
6 Welding . 2
7 Requirements . 2
7.1 Chemical composition . 2
7.2 Mechanical properties . 2
8 Inspection and testing . 2
8.1 General . 2
8.2 Sampling . 3
8.3 Formation of test lots . 3
8.4 Non-destructive testing . 3
8.5 Marking . 3
9 Supplementary requirements . 3
Annex A (normative) Supplementary requirements .11
Annex B (informative) Welding conditions .14
Annex C (informative) Creep properties.15
Annex D (informative) UNS cast grades similar to ISO cast grades .17
Bibliography .19
© ISO 2015 – All rights reserved iii

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ISO 4991:2015(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 on the meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is The committee responsible for this document is
ISO/TC 17, Steel, Subcommittee SC 11, Steel castings.
This third edition cancels and replaces the second edition (ISO 4991:2005), which has been technically
revised. In particular, the following changes have been made:
— new and replacement International Standards have been added to the normative references (see
Clause 2);
— a new numbering system has been included in all tables;
— in Table 1, grade designations and composition limits have been changed where appropriate.
— a new Annex D containing Table D.1, showing UNS grades similar to ISO cast grades, has been added.
iv © ISO 2015 – All rights reserved

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INTERNATIONAL STANDARD ISO 4991:2015(E)
Steel castings for pressure purposes
1 Scope
This International Standard covers steel castings for pressure containing parts.
It includes materials which are used for the manufacture of components subject to pressure vessel
codes and components not subject to codes.
This International Standard relates to castings manufactured from unalloyed and alloyed steel grades
(characterized by their chemical composition, Table 1, and mechanical properties, Tables 2, 3, 4 and 5).
NOTE Annex D gives information on ISO grade designation and available UNS numbers which are similar to
the ISO grade designation.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
ISO 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 4885, Ferrous products — Heat treatments — Vocabulary
ISO 4990, Steel castings — General technical delivery requirements
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 6892-2, Metallic materials — Tensile testing — Part 2: Method of test at elevated temperature
ISO 11970, Specification and approval of welding procedures for production welding of steel castings
ISO 13520, Determination of ferrite content in austenitic stainless steel castings
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4885 and ISO 4990 apply.
4 Information to be supplied by the purchaser
Materials specified in this International Standard shall conform to the applicable requirements of
ISO 4990 including the supplementary requirements listed in Annex A that are indicated in the enquiry
and purchase order.
5 Heat treatment
The type of heat treatment shall comply with Table 6 for the specified grades. The temperatures given
are for information only.
When a grade may be delivered at different strength levels depending on the type of heat treatment (see
Table 2), the purchaser shall state at the time of enquiry and order the type of heat treatment required.
The symbols for the type of heat treatment are as follows:
© ISO 2015 – All rights reserved 1

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ISO 4991:2015(E)

   +N  normalized
   +QT  quenched and tempered
   +AT  solution annealed
NOTE For definitions, see ISO 4885.
6 Welding
Welding is permitted, unless otherwise agreed. All the welds shall conform to the same criteria for
non-destructive testing as the relevant part of the casting. Welding shall be carried out in accordance
with ISO 11970.
The welding conditions are given in Annex B.
7 Requirements
7.1 Chemical composition
An analysis of each heat shall be made by the manufacturer to determine the contents of the
specified elements.
The chemical composition shall comply with the values given in Table 1.
Permissible deviations for the product analysis are indicated in ISO 4990.
7.2 Mechanical properties
The mechanical properties shall comply with the values given in Tables 2, 3, 4 and 5.
Mechanical properties shall be measured on test pieces taken from test blocks (according to ISO 4990).
The tensile tests at room temperature shall be carried out according to ISO 6892-1 and, if specified,
impact tests according to ISO 148-1.
If required by agreement at the time of enquiry and order, impact energy properties at low temperature
shall comply with Table 3.
If required by agreement at the time of enquiry and order, impact energy values at room temperature
shall comply with Table 4.
If required by agreement at the time of enquiry and order, verification of the elevated temperature
proof stress values shall be carried out at elevated temperatures in accordance with ISO 6892-2. In such
a case, the values shall comply with Table 5.
Creep resistance mean values are given for information, for some grades in Annex C.
8 Inspection and testing
8.1 General
For all products ordered to the requirements of this International Standard, specific inspection and
testing is required.
2 © ISO 2015 – All rights reserved

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ISO 4991:2015(E)

8.2 Sampling
Test blocks shall be heat treated in production furnaces to the same procedure as the castings they
represent.
Test pieces shall not be cut from the test block until the latter has been heat treated.
8.3 Formation of test lots
The formation of test lots shall be carried out in accordance with ISO 4990.
8.4 Non-destructive testing
The following information shall be given at the time of enquiry and order in accordance with ISO 4990:
— non-destructive methods required,
— area to be examined,
— acceptance criteria required.
8.5 Marking
8.5.1 Castings shall be marked for material identification. In addition, heat numbers, or serial numbers
that are traceable to heat numbers, shall be marked on all castings. For small castings, it may be agreed
at the time of the enquiry and order that they may be batched and that their identification is marked on a
label attached to each batch.
8.5.2 Castings shall be marked with the manufacturer’s identification or symbol except where other
provisions have been made between the manufacturer and purchaser.
8.5.3 When more than one heat treatment type is available, the heat treatment applied shall be marked
with a suffix added to the grade designation (see Table 2).
9 Supplementary requirements
This International Standard also specifies supplementary requirements, which may be applied to steel
castings. These requirements are provided for use when additional testing or inspection is desired and
apply only when individually specified by the purchaser.
A list of supplementary requirements which may be used at the option of the purchaser is given in
ISO 4990 and in Annex A.
If ferrite determination is required for austenitic and austenitic-ferritic grades, it may be made
using ISO 13520.
© ISO 2015 – All rights reserved 3

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ISO 4991:2015(E)

4 © ISO 2015 – All rights reserved
Table 1 — Chemical composition, in per cent, mass fraction
Grade designation C Si Mn P S Cr Mo Ni V Cu Other
Name Number max. max. max.
a a b
GP240GH 1.0619 0,18–0,23 0,60 0,50–1,20 0,030 0,020 0,30 max. 0,12 max. 0,40 max. 0,03 max. 0,30 max.
a a b
GP280GH 1.0625 0,18–0,25 0,60 0,80–1,20 0,030 0,020 0,30 max. 0,12 max. 0,40 max. 0,03 max. 0,30 max.
b
G17Mn5 1.1131 0,15–0,20 0,60 1,00–1,60 0,020 0,025 0,30 max. 0,12 max. 0,40 max. 0,03 max. 0,30 max.
G20Mn5 1.6220 0,17–0,23 0,60 1,00–1,60 0,020 0,020 0,30 max. 0,12 max. 0,80 max. 0,03 max. 0,30 max.
G18Mo5 1.5422 0,15–0,20 0,60 0,80–1,20 0,020 0,020 0,30 max. 0,45–0,65 0,40 max. 0,050 max. 0,30 max.
G20Mo5 1.5419 0,15–0,23 0,60 0,50–1,00 0,025 0,020 0,30 max. 0,40–0,60 0,40 max. 0,050 max. 0,30 max.
G17CrMo5–5 1.7357 0,15–0,20 0,60 0,50–1,00 0,020 0,020 1,00–1,50 0,45–0,65 0,40 max. 0,050 max. 0,30 max.
G17CrMo9–10 1.7379 0,13–0,20 0,60 0,50–0,90 0,020 0,020 2,00–2,50 0,90–1,20 0,40 max. 0,050 max. 0,30 max.
G12MoCrV5–2 1.7720 0,10–0,15 0,45 0,40–0,70 0,030 0,020 0,30–0,50 0,40–0,60 0,40 max. 0,22–0,30 0,30 max.
G17CrMoV5–10 1.7706 0,15–0,20 0,60 0,50–0,90 0,020 0,015 1,20–1,50 0,90–1,10 0,40 max. 0,20–0,30 0,30 max.
G25NiCrMo3 1.6553 0,23–0,28 0,80 0,60–1,00 0,030 0,025 0,40–0,80 0,15–0,30 0,40–0,80 0,03 max. 0,30 max.
G25NiCrMo6 1.6554 0,23–0,28 0,60 0,60–0,90 0,030 0,025 0,70–0,90 0,20–0,30 1,00–2,00 0,03 max. 0,30 max.
G17NiCrMo13–6 1.6781 0,15–0,19 0,50 0,55–0,80 0,015 0,015 1,30–1,80 0,45–0,60 3,00–3,50 0,050 max. 0,30 max.
G9Ni10 1.5636 0,06–0,12 0,60 0,50–0,80 0,020 0,015 0,30 max. 0,20 max. 2,00–3,00 0,050 max. 0,30 max.
G9Ni14 1.5638 0,06–0,12 0,60 0,50–0,80 0,020 0,015 0,30 max. 0,20 max. 3,00–4,00 0,050 max. 0,30 max.
GX15CrMo5 1.7365 0,12–0,19 0,80 0,50–0,80 0,025 0,025 4,00–6,00 0,45–0,65 - 0,05 0,30 max.
GX10CrMoV9–1 1.7367 0,08–0,12 0,20–0,50 0,30–0,60 0,030 0,010 8,0–9,5 0,85–1,05 0,40 max 0,18–0,25 - Nb 0,060–0,10
N 0,030–0,070
Al 0,02max
Ti 0,01 max
Zr 0,01 max
GX15CrMo9–1 1.7376 0,12–0,19 1,00 0,35–0,65 0,030 0,030 8,00–10,00 0,90–1,20 0,40 max. 0,05 0,30 max.
GX8CrNi12–1 1.4107 0,10 max. 0,40 0,50–0,80 0,030 0,020 11,50–12,50 0,50 max. 0,80–1,50 0,08 max. 0,30 max.
GX23CrMoV12–1 1.4931 0,20–0,26 0,40 0,50–0,80 0,030 0,020 11,30–12,20 1,00–1,20 1,00 max. 0,25–0,35 0,30 max. W 0,50 max
GX3CrNi13–4 1.6982 0,05 max. 1,00 1,00 max. 0,035 0,015 12,00–13,50 0,70 max. 3,50–5,00 0,08 max. 0,30 max.
GX4CrNi13–4 1.4317 0,06 max. 1,00 1,00 max. 0,035 0,025 12,00–13,50 0,70 max. 3,50–5,00 0,08 max. 0,30 max.
GX4CrNiMo16–5-1 1.4405 0,06 max. 0,80 1,00 max. 0,035 0,025 15,00–17,00 0,70–1,50 4,00–6,00 0,08 max. 0,30 max.
a
For each reduction of 0,01 % carbon below the maximum specified, an increase of 0,04 % manganese above the maximum specified will be permitted to a maximum of 1,40 %.
b
%Cr + %Mo + %Ni + %V + %Cu ≤ 1,00 %.

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ISO 4991:2015(E)

© ISO 2015 – All rights reserved 5
Table 1 (continued)
Grade designation C Si Mn P S Cr Mo Ni V Cu Other
Name Number max. max. max.
GX2CrNiN19–11 1.4487 0,030 max. 1,50 2,00 max. 0,035 0,030 18,00–20,00 - 9,00–12,00 - 0,50 max. 0,12 ≤ N ≤ 0,20
GX5CrNi19–10 1.4308 0,07 max. 1,50 1,50 max. 0,040 0,030 18,00–20,00 - 8,00–11,00 - 0,50 max.
GX5CrNiNb19–11 1.4552 0,07 max. 1,50 1,50 max. 0,040 0,030 18,00–20,00 - 9,00–12,00 - 0,50 max. 8xC ≤ Nb ≤ 1,00
GX2CrNiMoN19–11–2 1.4490 0,030 max. 1,50 2,00 max. 0,035 0,030 18,00–20,00 2,00–2,50 9,00–12,00 - 0,50 max. 0,12 ≤ N ≤ 0,20
GX5CrNiMo19–11–2 1.4408 0,07 max. 1,50 1,50 max. 0,040 0,030 18,00–20,00 2,00–2,50 9,00–12,00 - 0,50 max.
GX5CrNiMoNb19–11–2 1.4581 0,07 max. 1,50 1,50 max. 0,040 0,030 18,00–20,00 2,00–2,50 9,00–12,00 - 0,50 max. 8xC ≤ Nb ≤ 1,00
GX2CrNiMoN22
...

DRAFT INTERNATIONAL STANDARD
ISO/DIS 4991
ISO/TC 17/SC 11 Secretariat: ANSI
Voting begins on: Voting terminates on:
2013-09-30 2013-12-30
Steel castings for pressure purposes
Pièces moulées en acier pour service sous pression
[Revision of second edition (ISO 4991:2005)]
ICS: 77.140.80;77.140.30
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 4991:2013(E)
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 SUPPORTING DOCUMENTATION. ISO 2013

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ISO/DIS 4991:2013(E)

Copyright notice
This ISO document is a Draft International Standard and is copyright-protected by ISO. Except as
permitted under the applicable laws of the user’s country, neither this ISO draft nor any extract
from it may be reproduced, stored in a retrieval system or transmitted in any form or by any means,
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Reproduction may be subject to royalty payments or a licensing agreement.
Violators may be prosecuted.
ii © ISO 2013 – All rights reserved

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ISO DIS 4991
Contents Page
Foreword . iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Information to be supplied by the purchaser . 2
5 Heat treatment . 2
6 Welding . 2
7 Requirements . 2
7.1 Chemical composition . 2
7.2 Mechanical properties . 2
8 Testing and inspection . 3
8.1 Sampling . 3
8.2 Formation of test lots . 3
8.3 Non destructive testing . 3
8.4 Marking . 3
9 Supplementary requirements . 3
Annex A (normative) Supplementary requirements of ISO 4990 . 11
Annex B (informative) Welding conditions (for guidance only) . 13
Annex C (informative) Creep properties . 14

Annex D (informative) Similar UNS materials…………………………………………………………………………….15
Annex E (informative) Changes to ISO 4991…………………………………………………………………………….16
© ISO 2001 – All rights reserved iii

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ISO DIS 4991
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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 4991 was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 11,
Steel castings.

iv © ISO 2001 – All rights reserved

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ISO DIS 4991

Steel castings for pressure purposes
1 Scope
This International Standard covers steel castings for pressure containing parts.
It includes materials which are used for the manufacture of components subject to pressure vessel codes and
components not subject to codes.
This standard relates to castings manufactured from unalloyed and alloyed steel grades (characterised by their
chemical composition, table 1, and mechanical properties, tables 2 to 5).
NOTE Annex D gives information on ISO grade designation and available UNS numbers which are similar to the ISO
grade designation.

2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 148-1 Metallic materials - Charpy pendulum impact test – Part 1: Test method
ISO 488 Ferrous products -- Heat treatments -- Vocabulary
ISO 4990 Steel castings - General technical delivery requirements
ISO 6892-1 Metallic materials -- Tensile testing -- Part 1: Method of test at room temperature
ISO 6892-2 Metallic materials -- Tensile testing -- Part 2: Method of test at elevated temperature
ISO 11970:2001, Specifications and approval of welding procedures for production welding of steels castings
ISO 13520:2002, Steel castings - Estimation of ferrite content in austenitic stainless steel castings.
3 Terms and definitions
For the purposes of this international standard the terms and definitions given in ISO 4885 and ISO 4990 apply.
© ISO 2001 – All rights reserved 1

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ISO DIS 4991
4 Information to be supplied by the purchaser
Materials specified in this International Standard shall conform to the applicable requirements of ISO 4990
including the supplementary requirements listed in Annex A that are indicated in the enquiry and purchase order.
5 Heat treatment
The type of heat treatment shall comply with table 6 for the specified grades. The temperatures given are for
information only.
When a grade may be delivered at different strength levels depending on the type of heat treatment (see table 2),
the purchaser shall state at the time of enquiry and order the type of heat treatment required.
The symbols for the type of heat treatment are as follows:
+N normalized
+QT quenched and tempered
+AT solution annealed
NOTE For definitions see ISO 4885
6 Welding
Welding is permitted, unless otherwise agreed. All the welds shall conform to the same criteria for non-destructive
testing as the relevant part of the casting. Welding shall be carried out in accordance with ISO 11970.
The welding conditions are given in Annex B.
7 Requirements
7.1 Chemical composition
An analysis of each heat shall be made by the manufacturer to determine the percentages of the specified
elements.
The chemical composition shall comply with the values given in table 1.
Permissible deviations on check analysis are indicated in ISO 4990.
7.2 Mechanical properties
The mechanical properties shall comply with the values given in tables 2 to 5:
Mechanical properties shall be measured on test pieces taken from test blocks (according to ISO 4990).
The tensile tests at room temperature shall be carried out according to ISO 6892 and, if specified, impact tests
according to ISO 148.
If required by agreement at the time of enquiry and order, impact energy properties at low temperature shall comply
with table 3,
If required by agreement at the time of enquiry and order, impact energy values at room temperature shall comply
with table 4,
2 © ISO 2001 – All rights reserved

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ISO DIS 4991
If required by agreement at the time of enquiry and order, verification of the elevated temperature proof stress
values shall be carried out at elevated temperatures in accordance with ISO 783. In such case the values shall
comply with table 5.
Creep resistance mean values are given for information, for some grades in annex C.
8 Inspection and testing
For all products ordered to the requirements of this standard, specific inspection and testing is required.
8.1 Sampling
Test blocks shall be heat treated in production furnaces to the same procedure as the castings they represent.
Test pieces shall not be cut from the test block until the latter has been heat treated.
8.2 Formation of test lots
The formation of test lots shall be carried out in accordance with ISO 4990.
8.3 Non-destructive testing
The following information shall be given at the time of enquiry and order in accordance with ISO 4990 :
⎯ non-destructive methods required,
⎯ area to be examined,
⎯ acceptance criteria required.
8.4 Marking
8.4.1 Castings shall be marked for material identification. In addition, heat numbers, or serial numbers that are
traceable to heat numbers, shall be marked on all castings. For small castings it may be agreed at the time of the
enquiry and order that they may be batched and that their identification is marked on a label attached to each
batch.
8.4.2 Castings shall be marked with the manufacturer's identification or symbol except where other provisions
have been made between the manufacturer and purchaser.
8.4.3 When more than one heat treatment type is available, the heat treatment applied shall be marked with a
suffix added to the grade designation (see table 2).
9 Supplementary requirements
This International standard also specifies a group of supplementary requirements, which may be applied to steel
castings. These requirements are provided for use when additional testing or inspection is desired and apply only
when individually specified by the purchaser.
A list of supplementary requirements which may be used at the option of the purchaser is given in ISO 4990 and in
annex A.
If ferrite measurement is required for austenitic and austenitic-ferritic grades, it may be made using ISO 13520.
© ISO 2001 – All rights reserved 3

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ISO DIS 4991

Table 1 — Chemical composition, in % by mass
C Si Mn P S Cr Mo Ni V Cu Others
Grade Designation
Number max. max. max.
Name
a a b
GP240GH 1.0619 0,18-0,23 0,60 0,50-1,20 0,030 0,020 0,30 max. 0,12 max. 0,40 max. 0,03 max. 0,30 max.
a a b
GP280GH 1.0625 0,18-0,25 0,60 0,80-1,20 0,030 0,020 0,30 max. 0,12 max. 0,40 max. 0,03 max. 0,30 max.
b
G17Mn5 1.1131 0,15-0,20 0,60 1,00-1,60 0,020 0,025 0,30 max. 0,12 max. 0,40 max. 0,03 max. 0,30 max.

G20Mn5 1.6220 0,17-0,23 0,60 1,00-1,60 0,020 0,020 0,30 max. 0,12 max. 0,80 max. 0,03 max. 0,30 max.
G18Mo5 1.5422 0,15-0,20 0,60 0,60-1,00 0,020 0,020 0,30 max. 0,45-0,65 0,40 max. 0,050 max. 0,30 max.
G20Mo5 1.5419 0,15-0,23 0,60 0,50-1,00 0,025 0,020 0,30 max. 0,40-0,60 0,40 max. 0,050 max. 0,30 max.
G17CrMo5-5 1.7357 0,15-0,20 0,60 0,50-1,00 0,020 0,020 1,00-1,50 0,45-0,65 0,40 max. 0,050 max. 0,30 max.
G17CrMo9-10 1.7379 0,13-0,20 0,60 0,50-0,90 0,020 0,020 2,00-2,50 0,90-1,20 0,40 max. 0,050 max. 0,30 max.
G12MoCrV5-2 1.7720 0,10-0,15 0,45 0,40-0,70 0,030 0,020 0,30-0,50 0,40-0,60 0,40 max. 0,22-0,30 0,30 max.
G17CrMoV5-10 1.7706 0,15-0,20 0,60 0,50-0,90 0,020 0,015 1,20-1,50 0,90-1,10 0,40 max. 0,20-0,30 0,30 max.
G25NiCrMo3 1.6553 0,23-0,28 0,80 0,60-1,00 0,030 0,025 0,40-0,80 0,15-0,30 0,40-0,80 0,03 max. 0,30 max.
G25NiCrMo6 1.6554 0,23-0,28 0,60 0,60-0,90 0,030 0,025 0,70-0,90 0,20-0,30 1,00-2,00 0,03 max. 0,30 max.
G17NiCrMo13-6 1.6781 0,15-0,19 0,50 0,55-0,80 0,015 0,015 1,30-1,80 0,45-0,60 3,00-3,50 0,050 max. 0,30 max.
G9Ni10 1.5636 0,06-0,12 0,60 0,50-0,80 0,020 0,015 0,30 max. 0,20 max. 2,00-3,00 0,050 max. 0,30 max.
G9Ni14 1.5638 0,06-0,12 0,60 0,50-0,80 0,020 0,015 0,30 max. 0,20 max. 3,00-4,00 0,050 max. 0,30 max.
GX15CrMo5 1.7365 0,12-0,19 0,80 0,50-0,80 0,025 0,025 4,00-6,00 0,45-0,65 0,40 max. 0,05 0,30 max.
GX10CrMoV9-1 0,08-0,12 0,20-0,50 0,30-0,60 0,030 0,010 8,0-9,5 0,85-1,05 0,40 max 0,18-0,25 - Nb 0,060-0,10
N 0,030-0,070
Al 0,02max
Ti 0,01 max
Zr 0,01 max
GX15CrMo9-1 1.7376 0,12-0,19 1,00 0,35-0,65 0,030 0,030 8,00-10,00 0,90-1,20 0,40 max. 0,05 0,30 max.
GX8CrNi12-1 1.4107 0,10 max. 0,40 0,50-0,80 0,030 0,020 11,50-12,50 0,50 max. 0,80-1,50 0,08 max. 0,30 max.
GX23CrMoV12-1 1.4931 0,20-0,26 0,40 0,50-0,80 0,030 0,020 11,30-12,20 1,00-1,20 1,00 max. 0,25-0,35 0,30 max. W 0,50 max
GX3CrNi13-4 1.6982 0,05 max. 1,00 1,00 max. 0,035 0,015 12,00-13,50 0,70 max. 3,50-5,00 0,08 max. 0,30 max.
GX4CrNi13-4 1.4317 0,06 max. 1,00 1,00 max. 0,035 0,025 12,00-13,50 0,70 max. 3,50-5,00 0,08 max. 0,30 max.
GX4CrNiMo16-5-1 1.4405 0,06 max. 0,80 1,00 max. 0,035 0,025 15,00-17,00 0,70-1,50 4,00-6,00 0,08 max. 0,30 max.
GX2CrNiN19-11 1.4487 0,030 max. 1,50 2,00 max. 0,035 0,030 18,00-20,00 - 9,00-12,00 - 0,50 max. 0,12≤N≤0,20
GX5CrNi19-10 1.4308 0,07 max. 1,50 1,50 max. 0,040 0,030 18,00-20,00 - 8,00-11,00 - 0,50 max.
GX5CrNiNb19-11 1.4552 0,07 max. 1,50 1,50 max. 0,040 0,030 18,00-20,00 - 9,00-12,00 - 0,50 max. 8xC≤Nb≤1,00
GX2CrNiMoN19-11-2 1.4490 0,030 max. 1,50 2,00 max. 0,035 0,030 18,00-20,00 2,00-2,50 9,00-12,00 - 0,50 max. 0,12≤N≤0,20
GX5CrNiMo19-11-2 1.4408 0,07 max. 1,50 1,50 max. 0,040 0,030 18,00-20,00 2,00-2,50 9,00-12,00 - 0,50 max.
GX5CrNiMoNb19-11-2 1.4581 0,07 max. 1,50 1,50 max. 0,040 0,030 18,00-20,00 2,00-2,50 9,00-12,00 - 0,50 max. 8xC≤Nb≤1,00
GX2CrNiMoN22-5-3 1.4470 0,030 max. 1,00 2,00 max. 0,035 0,025 21,00-23,00 2,50-3,50 4,50-6,50 - 0,50 max. 0,12≤N≤0,20
© ISO 2001 – All rights reserved 4

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ISO DIS 4991
GX2CrNiMoCuN26-5-3-3 1.4451 0,030 max. 1,00 1,50 m
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