ISO/FDIS 18735
(Main)Ships and marine technology — High-manganese austenitic steel — Specification for high-manganese austenitic steel castings for cryogenic temperature
Ships and marine technology — High-manganese austenitic steel — Specification for high-manganese austenitic steel castings for cryogenic temperature
This document specifies minimum requirements for high manganese austenitic steel castings for valves, flanges and other pressure-containing components for cryogenic temperature. The specification of high manganese austenitic steel castings can be applicable to all pressure retaining components and any non-pressure retaining component. The selection of high manganese austenitic steel castings for a specific service including any necessary additional material requirements remains the responsibility of the end user.
Titre manque
General Information
Standards Content (Sample)
FINAL DRAFT
International
Standard
ISO/TC 8/SC 4
Ships and marine technology —
Secretariat: SAC
High-manganese austenitic steel —
Voting begins on:
Specification for high-manganese
2025-12-02
austenitic steel castings for
Voting terminates on:
cryogenic temperature
2026-01-27
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 8/SC 4
Ships and marine technology —
Secretariat: SAC
High-manganese austenitic steel —
Voting begins on:
Specification for high-manganese
austenitic steel castings for
Voting terminates on:
cryogenic temperature
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: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland Reference number
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Abbreviated terms . 3
5 Health, safety and quality requirements . 4
5.1 Health and safety requirements .4
5.2 Quality requirements .4
6 Material designation . . 4
7 Manufacture . 5
7.1 Steel making practice .5
7.2 Moulding .5
8 Chemical composition . 5
9 Heat treatment . 6
9.1 Temperature uniformity survey (TUS) for heat treatment furnace .6
9.2 Heat treatment.7
10 Mechanical properties . 7
10.1 Preparation of test specimens .7
10.2 Extent of testing .8
10.3 Mechanical properties .8
10.3.1 General .8
10.3.2 Tensile testing .8
10.3.3 Impact testing .9
10.3.4 Bend testing .9
10.4 Retesting .9
11 Inspection . 10
11.1 General requirements .10
11.2 Visual inspection .10
11.3 Liquid penetrant inspection .10
11.4 Radiographic inspection .10
11.5 Ultrasonic inspection.11
11.6 Hydrostatic testing .11
12 Repairs .12
13 Dimension inspection .13
14 Traceability, handling and packing .13
15 Documentation .13
Bibliography .15
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 TC 8, Ships and marine technology, Subcommittee SC
4, Outfitting and deck machinery.
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
Introduction
The aim of this document is to provide a set of common requirements for metallic materials used in cryogenic
[1] [2]
applications, in alignment with the IGC Code and IGF Code adopted by the International Maritime
Organization (IMO).
The newly developed, high-manganese austenitic steel is expected to possess mechanical properties
including Charpy impact energy values comparable to those materials for cryogenic service listed in both the
IGC Code and IGF Code. Consequently, high-manganese steel is intended to satisfy the strength requirements
of the structure of cargo tanks, fuel tanks and piping systems.
In addition, upon agreement with a purchaser, this document can be applied to piping systems for liquefied
hydrogen.
This document provides a standard specification of high-manganese austenitic steel castings for material
suppliers, ship owners, ship yards, manufacturers and shipping companies with regard to producing,
purchasing and using such materials.
v
FINAL DRAFT International Standard ISO/FDIS 18735:2025(en)
Ships and marine technology — High-manganese austenitic
steel — Specification for high-manganese austenitic steel
castings for cryogenic temperature
1 Scope
This document specifies minimum requirements for high-manganese austenitic steel castings for valves,
flanges and other pressure-containing components used at cryogenic temperature.
This document can be applicable to all pressure retaining components and any non-pressure retaining
component.
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 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 2566-1, Steel — Conversion of elongation values — Part 1: Carbon and low-alloy steels
ISO 2566-2, Steel — Conversion of elongation values — Part 2: Austenitic steels
ISO 4990, Steel castings — General technical delivery requirements
ISO 5173, Destructive tests on welds in metallic materials — Bend tests
ISO 5208, Industrial valves — Pressure testing of metallic valves
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 9606-1, Qualification testing of welders — Fusion welding — Part 1: Steels
ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel
ISO 10474, Steel and steel products — Inspection documents
ISO 15614-1, Specification and qualification of welding procedures for metallic materials — Welding procedure
test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloys
ASME B31.3, Process Piping
ASME Boiler and Pressure Vessel Code, Section V, Non-Destructive Testing
ASME Boiler and Pressure Vessel Code, Section VIII, Rules for Construction of Pressure Vessels Division 1
ASTM A991/991M, Standard Test Method for Conducting Temperature Uniformity Surveys of Furnaces Used to
Heat Treat Steel Products
ANSI/MSS SP-55, Quality Standard for Steel Castings for Valves, Flanges, and Fittings and Other Components -
visual method for evaluation of surface irregularities
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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/
3.1
chaplet
metallic support to maintain the space between a core and the mould
3.2
cryogenic service
service environment in which the minimum design temperature (3.4) is lower than −104 °C
3.3
DN
diameter nominal
alphanumeric designation of size that is common for components used in piping system, used for reference
purposes, comprising the letters “DN” followed by a dimensionless number indirectly related to the physical
size of the bore or outside diameter of the end connection as appropriate
Note 1 to entry: The dimensionless number following “DN” does not represent a measurable value and is not for
[3]
calculation purpose except where specified in ASME B16.34.
3.4
design temperature
minimum temperature for selection of materials at which cargo or fuel can be loaded or transported in the
cargo or fuel tanks
3.5
heat
molten metal poured from a single melting furnace or the molten metal from two or more furnaces poured
into a single ladle
3.6
high-manganese austenitic steel
steel with a high amount of manganese to retain austenitic as its primary phase at atmospheric and service
temperature
3.7
internal chill
metallic device placed in a mould cavity to promote directional solidification by increasing the rate of heat
extraction at a specific location
3.8
leak testing
hydrostatic leak test
pneumatic leak test
application of a pressure load, greater than the design load, to demonstrate the integrity of a pressure
system to safely withstand the design load
Note 1 to entry: ASME B31.3 uses the terms hydrostatic leak test, pneumatic leak test, or a combination of both
methods, such as a hydro-pneumatic test.
3.9
lot
two or more products having the same chemical composition (i.e. from the same melt), subjected to the
same heat treatment in the same furnace cycle, with the same product type and thickness within ±20 % of
the maximum thickness in the lot
3.10
manufacturer
organization, including subcontractors, which carries out operations (e.g. casting, heat treatment) that
affect the material properties of the finished product
3.11
NPS
nominal pipe size
alphanumeric designation of size that is common for components used in piping system, used for reference
purposes, comprising the letters “NPS” followed by a dimensionless number indirectly related to the physical
size of the bore or outside diameter of the end connection as appropriate
Note 1 to entry: The dimensionless size identification number following “NPS” does not represent a measurable value
and is not for calculation purpose except where specified in ASME B16.34. Prefix NPS usage is applicable to valves
bearing class designations.
3.12
pilot casting
casting made and tested as part of the initiation and development of the production method
EXAMPLE The first casting from a new or modified pattern, which is produced using identical foundry practices
as the production castings it is intended to represent.
3.13
purchaser
owner or another party acting on their behalf, who is responsible for procuring materials, components or
services intended for the design, construction or modification of castings
3.14
set temperature
target-holding temperature for heat treatment
3.15
test coupon
part from which the test specimens (3.16) are extracted
3.16
test specimen
part that is subject to mechanical testing
4 Abbreviated terms
For the purposes of this document, the following abbreviated terms are used.
ACCP ASNT Central Certification Program
AOD argon-oxygen-decarburization
API American Petroleum Institute
ASNT American Society for Non-destructive Testing
BPVC Boiler and Pressure Vessel code
DN Diameter Nominal
NDT non-destructive testing
NPS nominal pipe size
PT penetrant testing
RT radiographic testing
SMYS specified minimum yield strength
WPS welding procedure specification
5 Health, safety and quality requirements
5.1 Health and safety requirements
Each manufacturer is expected to operate according to all relevant statutory health and safety legislation
pertaining to the location where manufacturing, testing and inspection take place.
At least the following safety equipment and systems shall be provided:
— ventilation and extraction facilities for welding-related activities or work in a confined space;
— personal protective equipment including eye, breathing and hearing protection;
— access/scaffolding/working platforms and fall-arrest protective equipment for working at height;
— access and secure temporary formwork for working below product;
— protective systems to prevent electric shock and build-up, or discharge, of static electricity.
Each manufacturer shall manage all work undertaken during manufacturing, including cleaning, flushing
and leak testing activities.
5.2 Quality requirements
The foundry is responsible for carrying out effective quality, process and production controls, according to
the manufacturer's specifications.
[4]
NOTE For information on quality management systems, see ISO 9001.
The manufacturer shall prepare and document procedures for critical manufacturing processes, including
but not limited to melting, alloying, casting, heat treatment, welding, machining and non-destructive testing.
This document specifies the requirements for high-manganese austenitic steel castings, including chemical
composition and mechanical properties. See Clause 8 for chemical composition and Clause 10 for mechanical
properties.
6 Material designation
The high-manganese steel casting for cryogenic temperature is designated as follows:
“HMC xxx” which denotes High-manganese steel castings with SMYS xxx N/mm
where
HM is high-manganese steel
C is castings
XXX is the SMYS, expressed in N/mm .
7 Manufacture
7.1 Steel making practice
High-manganese steel shall be manufactured by electric furnace, open hearth or by other processes, with or
without separate refining such as argon-oxygen-decarburization (AOD), unless otherwise specified by the
purchaser.
Molten metal shall be killed by de-oxidation practice.
7.2 Moulding
The foundry shall prepare a relevant moulding procedure.
The
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ISO/DISFDIS 18735:2025(en)
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ISO /TC 8/SC 4 Style Definition
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Secretariat: SAC
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Date: 2025-04-2211-18
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Ships and marine technology — High -manganese austenitic steel –—
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cryogenic temperature
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St l D fi iti
ISO/DIS FDIS 18735:2025(en)
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Formatted: Font: Bold, English (United Kingdom)
Formatted: Font: Bold
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All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication Formatted: HeaderCentered, Line spacing: single
may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying,
Formatted: Default Paragraph Font
or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO
Formatted: Default Paragraph Font
at the address below or ISO’s member body in the country of the requester.
Formatted: Indent: Left: 0 cm, Right: 0 cm, Space
ISO copyright office
Before: 0 pt, No page break before, Adjust space
CP 401 • Ch. de Blandonnet 8
between Latin and Asian text, Adjust space between
CH-1214 Vernier, Geneva
Asian text and numbers
Phone: + 41 22 749 01 11
Formatted: English (United Kingdom)
Formatted: English (United Kingdom)
Fax: +41 22 749 09 47
EmailE-mail: copyright@iso.org
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Website: www.iso.orgwww.iso.org
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Published in Switzerland
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and numbers
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single
ii © ISO 18735 2025 – All rights reserved
ii
ISO/DISFDIS 18735:2025(en) Formatted: Font: 11 pt, Bold
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Contents
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Foreword . v
Adjust space between Asian text and numbers
Introduction . vi
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Abbreviated terms . 4
5 Health, safety and quality requirements . 4
5.1 Health and safety requirements . 4
5.2 Quality requirements . 5
6 Material designation . 5
7 Manufacture . 5
7.1 Steel making practice . 5
7.2 Moulding . 5
8 Chemical composition . 6
9 Heat treatment . 7
9.1 Temperature uniformity survey (TUS) for heat treatment furnace. 7
9.2 Heat treatment . 7
10 Mechanical properties . 8
10.1 Preparation of test specimens . 8
10.2 Extent of testing . 8
10.3 Mechanical properties . 9
10.4 Retesting . 10
11 Inspection . 11
11.1 General requirements . 11
11.2 Visual inspection . 11
11.3 Liquid penetrant inspection . 11
11.4 Radiographic inspection . 11
11.5 Ultrasonic inspection. 13
11.6 Hydrostatic testing . 13
12 Repairs . 13
13 Dimension inspection. 14
14 Traceability, handling and packing . 14
15 Documentation . 15
Bibliography . 16
Foreword . iv
Introduction . v
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1 Scope . 1 Formatted: FooterCentered, Left, Space Before: 0 pt,
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2 Normative references . 1
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3 Terms and definitions . 2
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4 Abbreviated terms . 4
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iii
ISO/DIS FDIS 18735:2025(en)
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5 Health, safety and quality requirements . 5
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5.1 Health and safety requirements . 5
5.2 Quality Requirements . 5
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6 Material designation . 5
7 Manufacture . 6
7.1 Steel making practice . 6
7.2 Moulding . 6
8 Chemical composition . 6
9 Heat treatment . 7
9.1 Temperature uniformity survey(TUS) for heat treatment furnace . 7
9.2 Heat treatment . 7
10 Mechanical properties . 8
10.1 Preparation of test specimens . 8
10.2 Extend of testing . 9
10.3 Mechanical properties . 9
10.3.1 General. 9
10.3.2 Tensile testing . 9
10.3.3 Impact testing . 9
10.3.4 Bend testing . 10
10.4 Retesting . 10
11 Inspection . 10
11.1 General requirements . 10
11.2 Visual inspection . 11
11.3 Liquid penetrant inspection . 11
11.4 Radiographic inspection . 11
11.5 Ultrasonic inspection. 12
11.6 Hydrostatic testing . 12
12 Repairs . 13
13 Dimension inspection. 14
14 Traceability, handling and packing . 14
15 Documentation . 14
Bibliography . 15
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single
iv © ISO 18735 2025 – All rights reserved
iv
ISO/DISFDIS 18735:2025(en) Formatted: Font: 11 pt, Bold
Formatted: Font: 11 pt, Bold
Formatted: Font: Bold
Foreword
Formatted: HeaderCentered, Left
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: Indent: Left 0 ch
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).
Formatted: English (United Kingdom)
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)
Formatted: Font color: Auto
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
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.htmlwww.iso.org/iso/foreword.html.
Formatted: English (United Kingdom)
This document was prepared by Technical Committee TC 8, Ships and marine technology, Subcommittee SC 4,
Formatted: Adjust space between Latin and Asian text,
Outfitting and deck machinery.
Adjust space between Asian text and numbers
Any feedback or questions on this document should be directed to the user’s national standards body. A
Formatted: English (United Kingdom)
complete listing of these bodies can be found at www.iso.org/members.htmlwww.iso.org/members.html.
Formatted: English (United Kingdom)
Formatted: Adjust space between Latin and Asian text,
Adjust space between Asian text and numbers
Formatted: Font: 10 pt
Formatted: FooterCentered, Left, Space Before: 0 pt,
Tab stops: Not at 17.2 cm
Formatted: Font: 11 pt
Formatted: FooterPageRomanNumber, Left, Space
After: 0 pt, Tab stops: Not at 17.2 cm
v
ISO/DIS FDIS 18735:2025(en)
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Formatted: Font: Bold, English (United Kingdom)
Formatted: Font: Bold
Introduction
Formatted: Font: Bold
Formatted: HeaderCentered, Line spacing: single
The aim of this document is to provide a set of common requirements for metallic materials used in cryogenic
[1][ ] [2][ ]
applications, in alignment with the IGC Code 1 and IGF Code 2 adopted by the International Maritime
Organization (IMO).
The newly developed, high -manganese austenitic steel is expected to possess mechanical properties
including Charpy impact energy values comparable to those materials for cryogenic service listed in both the
IGC Code and IGF Code. Consequently, high -manganese steel is intended to satisfy the strength requirements
of the structure of cargo tanks, fuel tanks and piping systems.
In addition, upon agreement with a purchaser, this document can be applied to piping systemsystems for
liquefied hydrogen.
This document provides a standard specification of high -manganese austenitic steel castings for material
suppliers, ship owners, ship yards, manufacturers and shipping companies with regard to producing,
purchasing and using such materials.
Formatted: Font: 11 pt
Formatted: FooterPageRomanNumber, Line spacing:
single
vi © ISO 18735 2025 – All rights reserved
vi
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DRAFT International Standard ISO/DIS 18735:2025(en)
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Ships and marine technology — High -manganese austenitic steel –—
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Specification for high -manganese austenitic steel castings for
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cryogenic temperature
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...
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1 Scope
Formatted
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This document specifies minimum requirements for high -manganese austenitic steel castings for valves,
Formatted
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flanges and other pressure-containing components used at cryogenic temperature.
Formatted
...
Formatted
This document can be applicable to all pressure retaining components and any non-pressure retaining
...
component.
Formatted
...
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...
2 Normative references
Formatted
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The following documents are referred to in the text in such a way that some or all of their content constitutes
Formatted
...
requirements of this document. For dated references, only the edition cited applies. For undated references,
Formatted
...
the latest edition of the referenced document (including any amendments) applies.
Formatted
...
ISO 148--1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
Formatted
...
Formatted
ISO 2566-1, Steel — Conversion of elongation values — Part 1: Carbon and low-alloy steels .
Formatted
...
ISO 2566-2, Steel — Conversion of elongation values — Part 2: Austenitic steels
Formatted
...
ISO 4990, Steel castings — General technical delivery requirements Formatted
...
Formatted
...
ISO 5173, Destructive tests on welds in metallic materials — Bend tests
Formatted
...
ISO 5208, Industrial valves — Pressure testing of metallic valves
Formatted
...
Formatted
...
ISO 6892--1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
Formatted
...
ISO 9606--1, Qualification testing of welders — Fusion welding — Part 1: Steels
Formatted
...
Formatted
...
ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel
Formatted
...
ISO 10474, Steel and steel products — Inspection documentsISO 15609-1, Specification and qualification of
Formatted
...
welding procedures for metallic materials — Welding procedure specification — Part 1: Arc weldingdocuments
Formatted
...
ISO 15614 -1, Specification and qualification of welding procedures for metallic materials — Welding procedure
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test — Part 1: Arc and gas welding of steels and arc welding of nickel and nickel alloysASME B31.3, Process
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Pipingalloys
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ASME B31.3, Process Piping
Formatted
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Formatted
ASME Boiler and Pressure Vessel Code, Section V, Non-Destructive TestingASMETesting .
Formatted
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ASME Boiler and Pressure Vessel Code, Section VIII, Rules for Construction of Pressure Vessels Division 1
Formatted
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ASTM A370, Standard test methods and definitions for mechanical testing of steel products
Formatted
...
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ASTM A991/991M, Standard Test Method for Conducting Temperature Uniformity Surveys of Furnaces Used
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to Heat Treat Steel Products
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ASTM E8, Standard test methods for tension testing of metallic materials
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ASTM E23, Standard Test Methods for Notched Bar Impact Testing of Metallic Materials
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stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
ASNT SNT-TC-1A, Personnel Qualification and Certification in Non-destructive Testing
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
ANSI/MSS SP-55, Quality Standard for Steel Castings for Valves, Flanges, and Fittings and Other Components
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- visual method for evaluation of surface irregularities
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3 Terms and definitions
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For the purposes of this document, the following terms and definitions apply.
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ISO and IEC maintain terminology databases for use in standardization at the following addresses:
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
— — ISO Online browsing platform: available at https://www.iso.org/obphttps://www.iso.org/obp
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— — IEC Electropedia: available at https://www.electropedia.org/https://www.electropedia.org/
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3.1 3.1
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chaplet
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metallic support to maintain the space between a core and the mould
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3.2
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controlled hydrogen welding process
and Asian text, Adjust space between Asian text and
welding process capable of depositing weld metal with a maximum diffusible hydrogen content of 5 ml/100 g
numbers
deposited metal
3.2 3.3
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cryogenic service
and Asian text, Adjust space between Asian text and
service environment in which the minimum design temperature (3.5)(3.4) is lower than -−104 °C numbers
3.3 3.4
DN
diameter nominal
alphanumeric designation of size that is common for components used in piping system, used for reference
purposes, comprising the letters "“DN"” followed by a dimensionless number indirectly related to the physical
size of the bore or outside diameter of the end connection as appropriate
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Note 1 to entry: The dimensionless number following "“DN"” does not represent a measurable value and is not for
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[3] [ ]
calculation purpose except where specified in ASME B16.34 . 3
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
3.4 3.5
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design temperature
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minimum temperature for selection of materials at which cargo or fuel can be loaded or transported in the
cargo or fuel tanks
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3.6
and Asian text, Adjust space between Asian text and
end user
numbers
Entity that is responsible for the operation of an installation/facility and its component
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Line spacing: single
2 © ISO 18735 2025 – All rights reserved
ISO/DISFDIS 18735:2025(en) Formatted: Font: 11 pt
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3.5 3.7
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heat
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molten metal poured from a single melting furnace or the molten metal from two or more furnaces poured
and Asian text, Adjust space between Asian text and
into a single ladle
numbers
3.6 3.8
high -manganese austenitic steel
steel with a high amount of manganese to retain austenitic as its primary phase at atmospheric and service
temperature
3.7 3.9
internal chill
metallic device placed in a mould cavity to promote directional solidification by increasing the rate of heat
extraction at a specific location
3.8
3.10
leak testing
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hydrostatic leak test
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pneumatic leak test
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application of a pressure load, greater than the design load, to demonstrate the integrity of a pressure system
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to safely withstand the design load
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Note 1 to entry: ASME B31.3 uses the terms hydrostatic leak test, pneumatic leak test, or a combination of both
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methods, such as a hydro-pneumatic test.
3.9 3.11
lot
two or more products having the same chemical composition (i.e. from the same melt), subjected to the same
heat treatment in the same furnace cycle, with the same product type and thickness within ±20 % of the
maximum thickness in the lot.
3.10 3.12
manufacturer
organization, including subcontractors, which carries out operations (e.g. casting, heat treatment) that affect
the material properties of the finished product
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3.11 3.13
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NPS
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nominal pipe size
stops: Not at 0.7 cm + 1.4 cm + 2.1 cm + 2.8 cm +
alphanumeric designation of size that is common for components used in piping system, used for reference
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
purposes, comprising the letters "“NPS"” followed by a dimensionless number indirectly related to the
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physical size of the bore or outside diameter of the end connection as appropriate
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Note 1 to entry: The dimensionless size identification number following "“NPS"” does not represent a measurable value
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and is not for calculation purpose except where specified in ASME B16.34. Prefix NPS usage is applicable to valves bearing
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class designations.
and Asian text, Adjust space between Asian text and
numbers
3.12 3.14
pilot casting
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casting made and tested as part of the initiation and development of the production method
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Tab stops: Not at 17.2 cm
EXAMPLE The first casting from a new or modified pattern, which is produced using identical foundry practices as
the production castings it is intended to represent. Formatted: Font: 11 pt
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3.13 3.15
purchaser
owner or another party acting on their behalf, who is responsible for procuring materials, components or
services intended for the design, construction or modification of castings
3.14 3.16
Formatted Table
set temperature
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target -holding temperature for heat treatment
and Asian text, Adjust space between Asian text and
numbers
3.15 3.17
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test coupon
and Asian text, Adjust space between Asian text and
part from which the test specimens (3.18are(3.16) are extracted
numbers
3.16 3.18
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test specimen and Asian text, Adjust space between Asian text and
part that is subject to mechanical testing numbers
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4 Abbreviated terms
and Asian text, Adjust space between Asian text and
numbers
For the purposes of this document, the following abbreviated terms are used.
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and Asian text, Adjust space between Asian text and
ACCP ASNT Central Certification Program
numbers
AOD Argon argon-oxygen -decarburization Formatted: Table body (+), Adjust space between Latin
and Asian text, Adjust space between Asian text and
API American Petroleum Institute
numbers
ASNT American Society for Non-destructive Testing
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and Asian text, Adjust space between Asian text and
BPVC Boiler and pressure vesselPressure Vessel code
numbers
DN Diameter Nominal
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NDT Nonnon-destructive testing
and Asian text, Adjust space between Asian text and
numbers
NPS Nominalnominal pipe size
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PT Penetrantpenetrant testing
and Asian text, Adjust space between Asian text and
numbers
RT Radiographicradiographic testing
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SMYS Specifiedspecified minimum yield strength
and Asian text, Adjust space between Asian text and
WPS Welding Procedure Specificationwelding procedure specification
numbers
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5 Health, safety and quality requirements
and Asian text, Adjust space between Asian text and
numbers
5.1 Health and safety requirements
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Latin and Asian text, Adjust space between Asian text
Each manufacturer is expected to operate in according to all relevant statutory health and safety legislation
and numbers
pertaining to the location where manufacturing, testing, and inspection take place.
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At least, the following safety equipment and systems shall be provided:
stops: Not at 0.71 cm
— — ventilation and extraction facilities for welding-related activities or work in a confined space; Formatted: Adjust space between Latin and Asian text,
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— — personal protective equipment including eye, breathing and hearing protection;
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— — access/scaffolding/working platforms and fall-arrest protective equipment for working at height;
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— — access and secure temporary formwork for working below product;
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4 © ISO 18735 2025 – All rights reserved
ISO/DISFDIS 18735:2025(en) Formatted: Font: 11 pt
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— — protective systems to prevent electric shock and build-up, or discharge, of static electricity;.
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Each manufacturer shall manage all work undertaken during manufacturing, including cleaning, flushing and
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leak testing activities.
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5.2 Quality requirements
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The foundry is responsible for carrying out effective quality, process and production controls, according to the
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manufacturer's specifications . .
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[4] [ ]
NOTE For guidanceinformation on quality management systems, see ISO 9001 . 4
The manufacturer shall prepare and document procedures for critical manufacturing processes, including but
not limited to melting, alloying, casting, heat treatment, welding, machining, and non-destructive testing.
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This document specifies the requirements for high -manganese austenitic steel castings, including chemical
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composition and mechanical properties. See Clause 8See Clause 8 for chemical composition and Clause
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10Clause 10 for mechanical properties.
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6 Material designation
Formatted Table
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The high -manganese steel casting for cryogenic temperature is designated as follows:
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“HMC xxx” which denotes High Manganese Steel Castings-manganese steel castings with SMYS xxx N/mm
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where
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Formatted: Table body (+)
HM is High high-manganese steel
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C Is Castingsis castings
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XXX is the SMYS, expressed in N/mm .
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7 Manufacture Formatted: Table body (+)
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7.1 Steel making practice
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and numbers
High -manganese steel shall be manufactured by electric furnace, open hearth or by other processes, with or
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without separate refining such as argon-oxygen-decarburization (AOD), unless otherwise specified by the
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purchaser.
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Molten metal shall be killed by de-oxidation practice.
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7.2 Moulding
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The foundry shall prepare a relevant moulding procedure.
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The mould design, including gating, risers, and mould making, shall follow documented internal procedures
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that are based on established industry standards or proven foundry engineering practices.
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Unless otherwise agreed between the purchaser and the manufacturer, the dimension of test coupon shall
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conform to those specified in ISO 4990.
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Tab stops: Not at 17.2 cm
ASTM A1067/A1067M may be used as an alternative standard for specifying test coupon dimensions when
explicitly agreed upon between the manufacturer and the purchaser. Formatted: Font: 11 pt
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A separated test coupon can be used upon agreement with the purchaser, but the test coupon's thickness of
the test coupon shall not be less than 30 mm.
8 Chemical composition
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Asian text, Adjust space between Asian text and
An analysis of each heat (i.e. each batch of molten steel) shall be carried out by the manufacturer to determine
numbers
the mass fractions of each element specified in Table 1.Table 1.
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Chemical composition analysis is based on a test sample which is taken during the pouring of the molten metal
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into the mould.
3.5 cm + 4.2 cm + 4.9 cm + 5.6 cm + 6.3 cm + 7 cm
When more than one ladle is poured into a single mould, the molten metal in each ladle shall be analysed in
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accordance with Table 1.Table 1.
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When using one large single ladle for mixing molten metal from each separated heat, chemical analysis shall
be carried out after sufficient mixing of molten metal in the ladle.
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When performing chemical analysis for elements that are not specified in Table 1,Table 1, the manufacturer
may add elements, upon agreement with the purchaser, provided that these additions do not adversely affect Formatted: Font: 10 pt
the chemical composition and mechanical properties specified in this document. Residual elements such as
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Sn, Pb, Sb and As shall not be added intentionally.
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Table 1 — Chemical composition of high -manganese austenitic steel
Formatted Table
Dimensions in per cent (%) (mass fraction)
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C Mn Si P S Cr Cu B N
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0,35 to 23,0 to 0,10 to max. max. 0,25 to max. Maxmax.
min. 3,00
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0,55 26,0 0,50 0,030 0,010 0,70 0,005 1,0
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NOTE 1 These requirements apply to both heat and product analyses.
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NOTE 2 Aluminium content applies when there is a total aluminium of 0,03 % or over.
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NOTE 3 Other grain refining elements, e.g. Nb, V, Al, can be added by the manufacturer, provided it is within their
between Asian text and numbers
responsibility and control.
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Formatted
...
Product analysis is not mandatory, but may be carried out upon agreement between the manufacturer and
purchaser.
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...
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...
When product analysis is performed, specimens can be used, which are obtained from a finished product, or
Formatted
from broken tensile test specimens after mechanical testing .
...
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The product analysis result should conform to the requirements in Table 2.Table 2.
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Table 2 — Product analysis tolerance Formatted
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Formatted Table
Dimensions in per cent (%) (mass fraction)
Formatted
Elements Permissible variations
...
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...
C ±0,02
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...
Mn ±0,06
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...
Si ±0,1
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...
P ±0,010
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...
S ±0,005
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Cr ±0,10
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...
6 © ISO 18735 2025 – All rights reserved
ISO/DISFDIS 18735:2025(en) Formatted: Font: 11 pt
Formatted: Font: 11 pt
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Elements Permissible variations
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Cu ±0,05 Formatted: Font: 10 pt, Not Bold
B ±0,000 5 Formatted: Font: 10 pt, Not Bold
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N ±0,01
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Formatted Table
When a manufacturer adds elements whichthat are not specified in Table 2,Table 2, additional
limitationlimitations may be established upon agreement between the purchaser and manufacturer.
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9 Heat treatment
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9.1 Temperature uniformity survey (TUS) for heat treatment furnace
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All high -manganese austenitic steel castings shall be heat treated at austenitizing temperature and then
quenched in water.
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Latin and Asian text, Adjust space between Asian text
Heat treatment furnace and heat treatment for casting shall comply with the following requirements:
and numbers
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a) Before performing the temperature uniformity survey (TUS), all thermocouple and recording devices
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shall be calibrated.
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b) Heat treatment furnace temperature shall be effectively controlled by calibrated thermometers and
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temperature shall be recorded automatically.
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c) Heat treatment furnace temperature uniformity shouldshall be surveyed according toin accordance with Adjust space between Asian text and numbers
ASTM A991/A991M or other recognized standards, and castings shall be heat treated in the effective zone
Formatted: List Number 1, Indent: Left: 0 cm, First line:
of the furnace. Other recognized standards can also be referred to.
0 cm, Numbered + Level: 1 + Numbering Style: a, b, c,
… + Start at: 1 + Alignment: Left + Aligned at: 0 cm +
d) Effective zone survey temperature shall be within 30 °C below nor 100 °C above the heat treatment set
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temperature.
text, Adjust space between Asian text and numbers
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e) Temperature for furnace uniformity shall be recorded for a minimum of 30 min at the target temperature.
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f) Temperature variation of heat treatment furnace shall be within ± ± 14 °C of the ta
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