ISO 4987:2020

INTERNATIONAL ISO
STANDARD 4987
Third edition
2020-01
Corrected version
2020-03
Steel and iron castings — Liquid
penetrant testing
Pièces moulées en acier et en fer — Contrôle par ressuage
Reference number
ISO 4987:2020(E)
©
ISO 2020

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ISO 4987:2020(E)

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© ISO 2020
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ISO 4987:2020(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Ordering information . 1
5 Testing . 2
5.1 Operating mode . 2
5.2 Qualification of the operators . 2
5.3 Surface preparation . 2
5.4 Conditions of testing . 2
6 Acceptance criteria . 2
6.1 Definition of liquid penetrant indications . 2
6.1.1 General. 2
6.1.2 Non-linear indications (SP) . 2
6.1.3 Linear indication (LP) . 3
6.2 Severity levels . 4
6.2.1 General. 4
6.2.2 Non-linear indications . 4
6.2.3 Linear indications . 4
6.2.4 Selection of the severity level . 4
6.2.5 Designation of severity levels . 5
7 Classification of the indications and interpretation of results . 5
7.1 Classification of the indications using Tables 1 and 2 . 5
7.1.1 General. 5
7.1.2 Non-linear indications . 5
7.1.3 Linear indications . 5
7.2 Interpretation of results . 5
8 Retesting . 5
9 Post-examination cleaning procedures . 6
10 Test report . 6
Annex A (informative) Recommended surface finish for liquid penetrant testing .7
Annex B (informative) Reference figures — Non-linear isolated indications (SP).8
Annex C (informative) Reference figures — Linear indications (LP).13
Annex D (informative) Model of a liquid penetrant test report .28
Bibliography .30
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ISO 4987:2020(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.
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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 11, Steel
castings.
This third edition cancels and replaces the second edition (ISO 4987:2010), which has been technically
revised. The main changes compared to the previous edition are as follows:
— isolated non-linear indications are defined in 6.1.2;
— definition of aligned linear indications in 6.1.3 is corrected
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.
This corrected version of ISO 4987:2020 incorporates the following corrections:
— the main title has been corrected from "Steel castings" to "Steel and iron castings";
— in the Scope, the sentence has been corrected to read: "This document specifies a method for the
liquid penetrant testing of steel and iron castings".
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ISO 4987:2020(E)

Introduction
This document complements the general principles of liquid penetrant testing described in ISO 3452-1
with additional requirements of the steel foundry industry.
Liquid penetrant testing, as well as any other non-destructive testing, is part of a general or specific
assessment of the quality of a casting to be agreed between the purchaser and the manufacturer at the
time of acceptance of the order.
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INTERNATIONAL STANDARD ISO 4987:2020(E)
Steel and iron castings — Liquid penetrant testing
1 Scope
This document specifies a method for the liquid penetrant testing of steel and iron castings.
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 3059, Non-destructive testing — Penetrant testing and magnetic particle testing — Viewing conditions
ISO 3452-1, Non-destructive testing — Penetrant testing — Part 1: General principles
ISO 4990, Steel castings — General technical delivery requirements
ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel
3 Terms and definitions
No terms and definitions are listed in this document.
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 Ordering information
Subject to agreement between the manufacturer and the purchaser, enquiries and purchase orders for
castings requiring liquid penetrant testing should include the following information:
a) the area of the casting to be tested;
b) the qualification of the operators who will carry out the testing (see 5.2) or interpretation (see 7.2);
c) the frequency/number of castings to be tested;
d) the manufacturing stage, when liquid penetrant testing is to be performed;
e) the required surface finish of the areas to be tested;
f) the type of discontinuity;
g) the severity level.
The sensitivity can differ depending on the method of liquid penetrant testing selected. Therefore, the
severity levels required shall be selected as a function of the liquid penetrants used and the method
agreed between the manufacturer and the purchaser.
The severity level can vary depending on the area of the casting tested (see Tables 1 and 2).
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ISO 4987:2020(E)

5 Testing
5.1 Operating mode
Testing shall be carried out as specified in ISO 3452-1.
5.2 Qualification of the operators
Testing shall be performed by personnel qualified in accordance with ISO 9712 or equivalent recognised
standards. The qualification level of the personnel shall be agreed between the manufacturer and
purchaser by the time of the acceptance of the order.
5.3 Surface preparation
The surface to be tested shall be clean and free from oil, grease, moulding and coating residues, or
any other contaminant which could interfere with the correct implementation and interpretation of the
penetrant testing results. For small indications, it may be necessary to improve the surface condition.
Annex A provides guidance on recommended surface finish for testing based on indication allowed.
Surface treatment or cleaning techniques which may seal or close discontinuities are not allowed.
5.4 Conditions of testing
The testing shall be carried out unaided or at a maximum magnification of 3× under viewing conditions
in accordance with ISO 3059.
6 Acceptance criteria
6.1 Definition of liquid penetrant indications
6.1.1 General
Indications revealed by the liquid penetrant testing can have different shapes and sizes. The distinction
between the indications is made depending on the ratio of the length L of the indication to its width W,
in the manner described in 6.1.2 and 6.1.3.
6.1.2 Non-linear indications (SP)
Indications are considered to be non-linear when the length L is smaller than three times the width
W. Indications are considered to be aligned when the distance between non-linear indications is less
than 2 mm and at least three indications are aligned. An alignment of indications is considered to be a
unique non-linear indication and its length is equal to the overall length L of the alignment specified in
Table 1. Non-linear indications that are not aligned are considered to be isolated.
NOTE The symbol for non-linear indications is SP (S for surface and P for liquid penetrant).
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ISO 4987:2020(E)

Table 1 — Severity levels for liquid penetrant testing — Non-linear (SP) indications (isolated)
Severity levels
Characteristic
SP 001 SP 01 SP 1 SP 2 SP 3 SP 4 SP 5
Testing means Magnifying glass
Eye
or eye
Magnification for observation of penetrant
≤3 1
indication
Length L of the smallest indication to be
1
0,3 0,5 1,5 2 3 5 5
considered, in millimetres
Maximum number of non-linear indica-
5 6 8 8 12 20 32
tions allowed
Maximum individual length L allowed, in
2 a a a a a
1 2 3 6 9 14 21
millimetres
a
A maximum number of two indications of the designated dimension are permitted.
6.1.3 Linear indication (LP)
The indications are considered to be linear when the length L is greater than or equal to three times the
width W.
The lengths of the linear indications greater than the minimum length shall be added together and the
result shall be compared to the total (T) length specified in Table 2.
Table 2 — Severity level
...