ISO 12725:2019

INTERNATIONAL ISO
STANDARD 12725
Second edition
2019-03
Nickel and nickel alloy castings
Pièces moulées en nickel et alliages de nickel
Reference number
©
ISO 2019
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Alloy identification . 1
5 General requirements for delivery . 1
5.1 Information to be supplied by the purchaser . 1
5.2 Additional information to be supplied . 2
6 Manufacture . 2
6.1 Melting . 2
6.2 Heat treatment . 2
6.3 Welding . 2
6.3.1 General. 2
6.3.2 Restriction . 2
7 Requirements . 2
7.1 Composition . 2
7.2 Mechanical properties . 5
7.3 Supplementary requirements . 5
8 Marking . 6
9 Supplementary requirements . 6
Annex A (informative) Rules for nickel and nickel alloys identification based on chemical
symbols . 7
Annex B (informative) Supplementary requirements . 9
Bibliography .12
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 155, Nickel and nickel alloys.
This second edition cancels and replaces the first edition (ISO 12725:1997) which has been technically
revised. The main changes compared with the previous edition are as follows:
— the normative references have been updated;
— Clause 5, “General requirements for delivery”, has been added.
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 © ISO 2019 – All rights reserved

INTERNATIONAL STANDARD ISO 12725:2019(E)
Nickel and nickel alloy castings
1 Scope
This document specifies requirements for nickel and nickel alloy castings.
The grades specified represent types of alloys suitable for a broad range of application in a wide variety
of corrosive and high temperature environments.
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 6372, Nickel and nickel alloys — Terms and definitions
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 6372 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
4 Alloy identification
For the purposes of this document, the principles for alloy identification are as given in Annex A.
5 General requirements for delivery
5.1 Information to be supplied by the purchaser
The enquiry and order should include the following information.
a) A description of the casting(s) by pattern number and/or drawing. When a pattern is supplied, a
complete list of the pattern equipment should be included. When a drawing is not supplied, the
casting is purchased on the basis of the pattern. In this case, the foundry shall not be responsible
for the dimensions of the part.
NOTE Machining allowances, dimensional tolerances, and geometrical tolerances can be selected from
ISO 8062-3.
All modifications to be made to the drawing, for the technical requirements of the manufacturer,
shall be agreed between the manufacturer and the purchaser.
b) The material standard, delivery condition and grade.
5.2 Additional information to be supplied
Where appropriate, the enquiry and order should include additional information, for example:
a) any supplementary requirements in accordance with Annex B;
b) the non-destructive testing procedures to be used, the extent of the non-destructive testing and
the acceptance criteria;
c) the type of inspection document to be provided at the time of supply;
d) the size of a test lot, (see B.2.2);
e) the procedures for marking (in accordance with Clause 8), machining, protection, packaging,
loading, dispatching and the destination;
f) the submission of sample castings for approval before production quantities are produced;
g) the methods of statistical control to be used.
6 Manufacture
6.1 Melting
Nickel and nickel alloys shall be melted by the electric furnace process with or without separate
refining, such as argon-oxygen decarburization (AOD) or by the vacuum induction melting process.
6.2 Heat treatment
Castings shall be heat treated in accordance with the procedures given in Table 1.
6.3 Welding
6.3.1 General
Selection of welding material, which shall be compatible with the casting composition, is generally left
to the discretion of the manufacturer. However, as a supplementary requirement, selection of weld
material may be agreed between the manufacturer and the purchaser.
NOTE ISO 11970 gives terms and definitions used for welding purposes for steel castings.
6.3.2 Restriction
Castings made from grades NC2000 and NC4030 shall not be welded.
7 Requirements
7.1 Composition
Materials shall conform to the chemical composition requirements given in Table 2.
The methods of determination of the chemical composition shall be at the discretion of the
manufacturer. However, in cases of dispute, the method specified in an appropriate document shall be
used. If no International Standard exists, an analytical method appropriately validated and acceptable
by the purchaser shall be used.
2 © ISO 2019 – All rights reserved

Table 1 — Heat treatment for nickel and nickel alloy castings
a
Alloy identification
Heat treatment
Number Description
NC2100 C-Ni99, -HC As cast.
NC4020 C-NiCu30Si As cast.
NC4135 C-NiCu30 As cast.
NC4030 C-NiCu30Si3 As cast.
NC4130 C-NiCu30Nb2Si2 As cast.
NC0012 C-NiMo31 Heat to 1 095 °C minimum, hold for sufficient time to bring castings
to temperature and quench in water or rapid cool by other means.
NC0007 C-NiMo30Fe5 Heat to 1 095 °C minimum, hold for sufficient time to bring castings
to temperature and quench in water or rapid cool by other means.
NC6985 C-NiCr22Fe20Mo7Cu2 Heat to 1 095 °C minimum, hold for sufficient time to bring castings
to temperature and quench in water or rapid cool by other means.
NC6625 C-NiCr22Mo9Nb4 Heat to 1 175 °C minimum, hold for sufficient time to bring castings to
temperature and quench in water or rapid cool by other means.
NC6455 C-NiCr16Mo16 Heat to 1 175 °C minimum, hold for sufficient time to bring castings to
temperature and quench in water or rapid cool by other means.
NC0002 C-NiMo17Cr16Fe6W4 Heat to 1 175 °C minimum, hold for sufficient time to bring castings to
temperature and quench in water or rapid cool by other means.
NC6022 C-NiCr21Mo14Fe4W3 Heat to 1 205 °C minimum, hold for sufficient time to bring castings
to temperature and quench in water or rapid cool by other means.
NC0107 C-NiCr18Mo18 Heat to 1 175 °C minimum, hold for sufficient time to bring castings to
temperature and quench in water or rapid cool by other means.
NC6040 C-NiCr15Fe Class 1: As-cast.
Class 2: Heat to 1 040 °C minimum, hold for sufficient time to bring
castings to temperature and quench in water or rapid cool by other
means.
NC8826 C-NiFe30Cr20Mo3CuNb Heat to 930 °C to 980 °C, hold for sufficient time to bring castings to
temperature and allow to air cool.
NC2000 C-NiSi9Cu3 Heat to 970 °C to 1 000 °C, hold for sufficient time to bring castings to
temperature and allow to air cool.
a
For alloy identification, either the number or the description may be used.
4 © ISO 2019 – All rights reserved
Ta
...