ISO 4986:2020
(Main)Steel and iron castings — Magnetic particle testing
Steel and iron castings — Magnetic particle testing
This document specifies a method for the magnetic particle testing of ferro-magnetic steel and iron castings. It also gives acceptance criteria through severity levels defined by the nature, the area and the dimensions of the discontinuities present. This document is applicable to all ferro-magnetic castings, independent of the moulding method. A steel and iron casting is considered to be ferro-magnetic if the magnetic induction is greater than 1 T (Tesla) for a magnetic field strength of 2,4 kA/m. This document only applies to those areas of the castings specified for testing, as well as the percentage of castings to be tested.
Pièces moulées en acier et en fer — Contrôle par magnétoscopie
General Information
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 4986
Third edition
2020-02
Steel and iron castings — Magnetic
particle testing
Pièces moulées en acier et en fer — Contrôle par magnétoscopie
Reference number
ISO 4986:2020(E)
©
ISO 2020
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ISO 4986:2020(E)
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© ISO 2020
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ISO 4986:2020(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 . 3
6.1 Definition of magnetic particle testing indications . 3
6.1.1 General. 3
6.1.2 Non-linear indications (SM) . 3
6.1.3 Linear indications (LM) and aligned indications (AM). 3
6.2 Severity levels . 4
6.2.1 General. 4
6.2.2 Non-linear indications . 4
6.2.3 Linear and aligned indications . 4
6.2.4 Selection of the severity level . 5
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 and aligned indications . 6
7.2 Interpretation of results . 6
8 Cleaning after examination and demagnetization . 6
9 Test report . 6
Annex A (informative) Recommended surface finish for magnetic particle testing .8
Annex B (informative) Reference figures — Non-linear indications (SM) .9
Annex C (informative) Reference figures — Linear (LM) and aligned (AM) indications .14
Annex D (informative) Model of a magnetic particle test report .29
Bibliography .31
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ISO 4986:2020(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.
For an explanation on 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 the following
URL: 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 4986:2010), which has been technically
revised. The main changes compared to the previous edition are as follows:
— addition of definition of a cluster of non-linear (SM) in 6.1.2;
— addition of “aligned (AM) indications” in 6.1.3, 6.2.3, 6.2.4, 7.1.3 and Annex C
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.
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ISO 4986:2020(E)
Introduction
This document complements the general principles of magnetic particle testing described in ISO 9934-1
with additional requirements of the steel foundry industry.
Magnetic particle 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 4986:2020(E)
Steel and iron castings — Magnetic particle testing
1 Scope
This document specifies a method for the magnetic particle testing of ferro-magnetic steel and iron
castings.
It also gives acceptance criteria through severity levels defined by the nature, the area and the
dimensions of the discontinuities present.
This document is applicable to all ferro-magnetic castings, independent of the moulding method.
A steel and iron casting is considered to be ferro-magnetic if the magnetic induction is greater than 1 T
(Tesla) for a magnetic field strength of 2,4 kA/m.
This document only applies to those areas of the castings specified for testing, as well as the percentage
of castings to be tested.
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 4990, Steel castings — General technical delivery requirements
ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel
ISO 9934-1, Non-destructive testing — Magnetic particle testing — Part 1: General principles
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:
— IEC Electropedia: available at http:// www .electropedia .org/
— ISO Online browsing platform: available at http:// www .iso .org/ obp
4 Ordering information
Subject to agreement between the manufacturer and the purchaser, enquiries and purchase orders for
castings requiring magnetic particle 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 magnetic particle testing is to be performed;
e) the required surface finish of the areas to be tested (see 5.3):
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ISO 4986:2020(E)
f) if testing is to be performed in only one direction (see 5.1);
g) the method to be used (type of detection media);
h) whether or not the casting is to be demagnetized after testing has been performed (viz. maximum
residual field strength values);
i) that test is to be carried out in accordance with ISO 9934-1;
j) the type of discontinuity;
k) the severity level.
The sensitivity can differ depending on the method of magnetic particle testing selected. Therefore, the
severity levels required and the method shall be agreed between the manufacturer and the purchaser.
The severity level can vary depending on the method of magnetic particle testing selected and the area
of the casting tested (see Tables 1 and 2).
The indications produced by magnetic particle testing can be compared to reference figures. The
reference figures are included for convenience only. In the event of a dispute, reference shall be made to
the tables.
5 Testing
5.1 Operating mode
The operating mode shall be agreed between the purchaser and the supplier. Unless otherwise specified
(see Clause 4), it is necessary to carry out the test by magnetizing sequentially in two directions
perpendicular to each other (see ISO 9934-1).
When the direction of stress is known, the test may be performed in one direction only, in order to take
into account the most detrimental orientation of the indication.
NOTE The magnetic images are not necessarily corresponding to discontinuities as pseudo-defects can appear.
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 the
purchaser by the time of acceptance of the order.
5.3 Surface preparation
The surface to be tested shall be clean and free from oil, grease, sand, scale, moulding and coating
residues, or any other contaminant which can interfere with the correct implementation and
interpretation of the magnetic 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.
The surface may be either shot blasted with round or angular shot, or sand blasted, or ground or
machined so that the smallest relevant indication required can be evaluated.
The surface to be tested may be painted to provide a contrast before the test.
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.
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ISO 4986:2020(E)
6 Acceptance criteria
6.1 Definition of magnetic particle testing indications
6.1.1 General
Indications revealed by the magnetic particle testing can have different shapes and sizes. An overview
of types of indications is given in EN 1369. The distinction between linear and non-linear 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 (SM)
Indications are considered to be non-linear when the length L is smaller than three times the width
W. Indications are considered to be clustered when the distance between non-linear indications is less
than 2 mm and at least three indications are clustered. A cluster of indications is considered to be a
single non-linear indication when its length is equal to the overall length L of the cluster specified in
Table 1.
NOTE The symbol for nonlinear indications is SM (S for surface and M for magnetic particle).
Table 1 — Severity levels for magnetic particle testing — Non-linear (SM) indications (isolated)
Severity levels
Characteristic
SM 001 SM 01 SM 1 SM 2 SM 3 SM 4 SM 5
Testing means Magnifying glass
Eye
or eye
Magnification for observation of
≤3 1
penetrant indication
Length L of the smallest indication to be
1
0,3 1,5 2 3 5 5
considered, in millimetres
Maximum number of nonlinear
— — 8 8 12 20 32
indications allowed
Maximum individual length L allowed, in
2 a a a a a
0 1 3 6 9 14 21
millimetres
a
A maximum number of two indications of the designated dimension are permitted.
6.1.3 Linear indications (LM) and aligned indications (AM)
The indications are considered to be linear when the length L is greater than or equal to three times the
width W.
NOTE The symbol for linear indications is LM (L for linear and M for magnetic particle).
The lengths of linear indications greater than the length of smallest indication to be considered shall be
added together and the result shall be compared to the total (T) length specified in Table 2.
Indicat
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