SIST EN ISO 9934-1:2017

SLOVENSKI STANDARD
SIST EN ISO 9934-1:2017
01-marec-2017
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SIST EN ISO 9934-1:2015
1HSRUXãLWYHQRSUHVNXãDQMH3UHVNXãDQMH]PDJQHWQLPLGHOFLGHO6SORãQD
QDþHOD,62
Non-destructive testing - Magnetic particle testing - Part 1: General principles (ISO 9934-
1:2016)
Zerstörungsfreie Prüfung - Magnetpulverprüfung - Teil 1: Allgemeine Grundlagen (ISO
9934-1:2016)
Essais non destructifs - Magnétoscopie - Partie 1: Principes généraux du contrôle (ISO
9934-1:2016)
Ta slovenski standard je istoveten z: EN ISO 9934-1:2016
ICS:
19.100 Neporušitveno preskušanje Non-destructive testing
SIST EN ISO 9934-1:2017 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 9934-1:2017

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SIST EN ISO 9934-1:2017


EN ISO 9934-1
EUROPEAN STANDARD

NORME EUROPÉENNE

December 2016
EUROPÄISCHE NORM
ICS 19.100 Supersedes EN ISO 9934-1:2015
English Version

Non-destructive testing - Magnetic particle testing - Part 1:
General principles (ISO 9934-1:2016)
Essais non destructifs - Magnétoscopie - Partie 1: Zerstörungsfreie Prüfung - Magnetpulverprüfung - Teil
Principes généraux du contrôle (ISO 9934-1:2016) 1: Allgemeine Grundlagen (ISO 9934-1:2016)
This European Standard was approved by CEN on 21 October 2016.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 9934-1:2016 E
worldwide for CEN national Members.

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SIST EN ISO 9934-1:2017
EN ISO 9934-1:2016 (E)
Contents Page
European foreword . 3
2

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SIST EN ISO 9934-1:2017
EN ISO 9934-1:2016 (E)
European foreword
This document (EN ISO 9934-1:2016) has been prepared by Technical Committee ISO/TC 135 "Non-
destructive testing" in collaboration with Technical Committee CEN/TC 138 “Non-destructive testing”
the secretariat of which is held by AFNOR.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by June 2017, and conflicting national standards shall be
withdrawn at the latest by June 2017.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent
rights.
This document supersedes EN ISO 9934-1:2015.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 9934-1:2016 has been approved by CEN as EN ISO 9934-1:2016 without any
modification.


3

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SIST EN ISO 9934-1:2017

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SIST EN ISO 9934-1:2017
INTERNATIONAL ISO
STANDARD 9934-1
Third edition
2016-12-01
Non-destructive testing — Magnetic
particle testing —
Part 1:
General principles
Essais non destructifs — Magnétoscopie —
Partie 1: Principes généraux du contrôle
Reference number
ISO 9934-1:2016(E)
©
ISO 2016

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SIST EN ISO 9934-1:2017
ISO 9934-1:2016(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, 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.
ISO copyright office
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved

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SIST EN ISO 9934-1:2017
ISO 9934-1:2016(E)

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Qualification and certification of personnel . 2
5 Safety and environment . 2
6 Testing procedure . 2
7 Surface preparation . 2
8 Magnetization . 2
8.1 General requirements . 2
8.2 Verification of magnetization . 3
8.3 Magnetizing techniques . 4
8.3.1 General. 4
8.3.2 Current flow techniques . 4
8.3.3 Magnetic flow techniques . 6
9 Detection media .10
9.1 Properties and selection of media .10
9.2 Testing of detection media .10
9.3 Application of detection media .10
10 Viewing conditions .10
11 Overall performance test .10
12 Interpretation and recording of indications .11
13 Demagnetization .11
14 Cleaning .11
15 Test report .12
Annex A (informative) Example for determination of currents required to achieve specified
tangential field strengths for various magnetization techniques .13
Bibliography .17
© ISO 2016 – All rights reserved iii

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SIST EN ISO 9934-1:2017
ISO 9934-1:2016(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 World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is ISO/TC 135, Non-destructive testing, Subcommittee
SC 2, Surface methods.
This third edition cancels and replaces the second edition (ISO 9934-1:2015), of which it constitutes a
minor revision, with the modification for clarity of Clause 13 and other editorial improvements.
A list of all parts in the ISO 9934 series, published under the general title Non-destructive testing —
Magnetic particle testing, can be found on the ISO website.
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SIST EN ISO 9934-1:2017
INTERNATIONAL STANDARD ISO 9934-1:2016(E)
Non-destructive testing — Magnetic particle testing —
Part 1:
General principles
1 Scope
This document specifies general principles for the magnetic particle testing of ferromagnetic materials.
Magnetic particle testing is primarily applicable to the detection of surface-breaking discontinuities,
particularly cracks. It can also detect discontinuities just below the surface but its sensitivity diminishes
rapidly with depth.
This document specifies the surface preparation of the part to be tested, magnetization techniques,
requirements and application of the detection media, and the recording and interpretation of results.
Acceptance criteria are not defined. Additional requirements for the magnetic particle testing of
particular items are defined in product standards (see the relevant International Standards or
European standards).
This document does not apply to the residual magnetization method.
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 9934-2, Non-destructive testing — Magnetic particle testing — Part 2: Detection media
ISO 9934-3, Non-destructive testing — Magnetic particle testing — Part 3: Equipment
ISO 12707, Non-destructive testing — Magnetic particle testing — Vocabulary
EN 1330-1, Non-destructive testing — Terminology — Part 1: General terms
EN 1330-2, Non-destructive testing — Terminology — Part 2: Terms common to non-destructive
testing methods
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 12707, EN 1330-1 and
EN 1330-2 apply.
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
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4 Qualification and certification of personnel
It is assumed that magnetic particle testing is performed by qualified and capable personnel. In order
to provide this qualification, it is recommended to certify the personnel in accordance with ISO 9712 or
equivalent.
5 Safety and environment
International, regional, national and/or local regulations which include health, safety and environment
may exist and may need to be taken into account.
Magnetic particle testing often creates high magnetic fields close to the object under test and the
magnetizing equipment. Items sensitive to these fields should be excluded from such areas.
6 Testing procedure
When required at the time of enquiry and order, magnetic particle testing shall be performed in
accordance with a written procedure.
The procedure can take the form of a brief technique sheet, containing a reference to this and other
appropriate standards. The procedure should specify testing parameters in sufficient detail for the test
to be repeatable.
All testing shall be performed in accordance with an approved written procedure or the relevant
product standard shall be referenced
7 Surface preparation
Areas to be tested shall be free from dirt, scale, loose rust, weld spatter, grease, oil, and any other
foreign materials that can affect the test sensitivity.
The surface quality requirements are dependent upon the size and orientation of the discontinuity to
be detected. The surface shall be prepared so that relevant indications can be clearly distinguished
from false indications.
Non-ferromagnetic coatings up to approximately 50 µm thickness, such as unbroken adherent paint
layers, do not normally impair detection sensitivity. Thicker coatings reduce sensitivity. Under these
conditions, the sensitivity shall be verified.
There shall be a sufficient visual contrast between the indications and the test surface. For the non-
fluorescent technique, it might be necessary to apply a uniform, thin, temporarily adherent layer of
approved contrast aid paint.
8 Magnetization
8.1 General requirements
The minimum magnetic flux density (B) regarded as adequate for testing is 1 T. The applied magnetic
field (H) required to achieve this in low-alloy and low-carbon steels is determined by the relative
permeability of the material. This varies according to the material, the temperatures, and also with
the applied magnetic field and for these reasons, it is not possible to provide a definitive requirement
for the applied magnetic field. However, typically a tangential field of approximately 2 kA/m will be
required.
Where time varying currents (I) are used to produce a magnetic field (which will also be time varying),
it is important to control the crest factor (shape) of the waveform and the method of measurement
of the current in order to establish a repeatable technique. Both peak and RMS measurements are
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typically used and measurement of the values can be affected by the response of the instrument. For
this reason, only instruments that respond directly to the waveform shall be used (e.g. true RMS meters
with appropriate crest factor capability for accurate RMS measurements). Instruments that calculate
peak or RMS values based on theoretical calculation derived from other values shall not be used. This
shall also apply to instruments used to measure magnetic fields
Smooth shaped waveforms provide low crest factors and least variation between peak and true RMS
values and are regarded as preferable for magnetic particle testing. Waveforms with a crest factor
(i.e. l /l ) greater than 3 shall not be used without documented evidence of the effectiveness of the
pk RMS
technique.
When using multidirectional magnetization techniques, the current used shall be purely sinusoidal or
phase controlled but the phase cutting shall not be more than 90°. Practical demonstration that the
technique is effective in all directions shall be carried out (e.g. using sample parts with known defects
or shim type indicators).
Provided the permeability is in the normal range and the current measurement methods are controlled
as described, calculations based on the use of 2 kA/m can provide a valuable method of technique
preparation. The use of either peak current or true RMS current is acceptable if the crest factor is
known. Knowing the entire waveform of the magnetizing curve would be optimal, but knowing the
crest factor is a good practical approximation. For pure sinusoidal waveforms, the relationship between
peak, mean, and RMS is shown in Annex A. Techniques based on calculation shall be verified before
implementation.
NOTE 1 For steels, with low relative permeability, a higher tangential field strength might be necessary. If
magnetization is too high, spurious background indications can appear, which could mask relevant indications.
If cracks or other linear discontinuities are likely to be aligned in a particular direction, the magnetic
flux shall be aligned perpendicular to this direction where possible.
NOTE 2 The flux can be regarded as effective in detecting discontinuities aligned up to 60° from the optimum
direction. Full coverage can then be achieved by magnetizing the surface in two perpendicular directions.
Magnetic particle testing should be regarded as a surface NDT method; however, discontinuities close
to the surface can also be detected. For time varying waveforms, the depth of magnetization (skin
depth) will depend on the frequency of the current waveform. Magnetic leakage fields produced by
imperfections below the surface will fall rapidly with distance. Therefore, although magnetic particle
testing is not recommended for the detection of imperfections other than on the surface, it can be noted
that the use of smooth DC or rectified waveforms can improve detection of imperfections just below the
surface.
8.2 Verification of magnetization
The adequacy of the surface flux density shall be established by one or more of the following methods:
a) by testing a representative component containing fine natural or artificial discontinuities in the
least favourable locations;
b) by measuring the tangential field strength as close as possible to the surface (information on this is
given in ISO 9934-3);
c) by calculating the tangential field strength for current flow methods — simple calculations are
possible in many cases, and they form the basis for current values specified in Annex A;
d) by the use of other methods based on established principles.
Flux indicators (e.g. shim-type), placed in contact with the surface under test, provide a guide to the
magnitude and direction of the tangential field strength, but should not be used to verify that the
tangential field strength is acceptable.
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8.3 Magnetizing techniques
8.3.1 General
This subclause describes a range of magnetization techniques. Multi-directional magnetization can be
used to find discontinuities in any direction. In the case of simple-shaped objects, formulae are given
in Annex A for achieving approximate tangential field strengths. Magnetizing equipment shall meet the
requirements of and be used in accordance with ISO 9934-3.
Magnetizing techniques are described in the following subclauses.
More than one technique might be necessary to find discontinuities on all test surfaces and in all
orientations. Demagnetization might be required where the residual field from the first magnetization
cannot be overcome. Techniques other than those listed can be used provided they give adequate
magnetization, in accordance with 8.1.
8.3.2 Current flow techniques
8.3.2.1 Axial current flow
Current flow offers high sensitivity for detection of discontinuities parallel to the direction of the
current.
Current passes through the component, which shall be in good electrical contact with the pads. A typical
arrangement is shown in Figure 1. The current is assumed to be distributed evenly over the surface and
shall be derived from the peripheral dimensions. An example of approximate formula for the current
required to achieve a specified tangential field strength is given in Annex A.
Care shall be taken to avoid damage to the component at the point of electrical contacts. Possible
hazards include excessive heat, burning, and arcing.
Key
1 specimen 4 current
2 flaw 5 contact pad
3 flux density 6 contact head
Figure 1 — Axial current flow
8.3.2.2 Prods; Current flow
Current is passed between hand-held or clamped contact prods as shown in Figure 2, providing an
inspection of a small area of a larger surface. The prods are then moved in a prescribed pattern to
cover the required total area. Examples of testing patterns are shown in Figures 2 and 3. Approximate
formulae for the current required to achieve a specified tangential field strength are given in Annex A.
This technique offers the highest sensitivity for discontinuities elongated parallel to the direction of the
current. Particular care shall be taken to avoid surface damage due to burning or contamination of the
component by the prods. Arcing or excessive heating shall be regarded as a defect requiring a verdict
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ISO 9934-1:2016(E)

on acceptability. If further testing is required on such affected areas, it shall be carried out using a
different technique.
Dimensions in millimetres
Key
1 flaw
Figure 2 — Prods; Current flow
Key
1 overlap
Figure 3 — Prods; Current flow
8.3.2.3 Induced current flow
Current is induced in a ring shaped component by making it, in effect, the secondary of a transformer, as
shown in Figure 4. An example of an approximate formula for the induced current required to achieve a
specified tangential field strength is given in Annex A.
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Key
1 flux 4 flaw
2 specimen 5 transformer primary coil
3 current
Figure 4 — Induced current flow
8.3.3 Magnetic flow techniques
8.3.3.1 Threading conductor
Current is passed through an insulated bar or flexible cable, placed within the bore of a component or
through an aperture, as shown in Figure 5.
Key
1 insulated threading bar 4 current
2 flaws 5 specimen
3 flux density
Figure 5 — Threading conductor
This method offers the highest sensitivity for discontinuities parallel to the direction of current flow.
The example of approximate formula given in Annex A for a central conductor is also applicable in this
case. For a non-central conductor, the tangential field strength shall be verified by measurement.
8.3.3.2 Adjacent conductor(s)
One or more insulated current-carrying cables or bars are laid parallel to the surface of the component,
adjacent to the area to be tested and supported at a distance, d, above it, as shown in Figures 6 and 7.
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ISO 9934-1:2016(E)

Key
1 current
2 flux density
3 flaw
Figure 6 — Adjacent conductor
Key
1 current
2 n turns
3 flaw direction
Figure 7 — Adjacent cable (coiled)
The adjacent conductor technique of magnetization requires the material being tested to be in close
proximity to a current flowing in one direction. The return cable for the electric current shall be
arranged to be as far removed from the testing zone as possible and, in all cases, this distance shall be
greater than 10 d, where 2 d is the width of the tested area
The cable shall be moved over the component at intervals of less than 2 d to ensure that the inspection
areas overlap. An example of an approximate formula for the current required to achieve a specified
tangential field strength in the test zone is given in Annex A.
8.3.3.3 Fixed installation
The component, or a portion of it, is placed in contact with the poles of an electromagnet, as shown in
Figure 8.
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ISO 9934-1:2016(E)

Key
1 current 4 pole piece
2 specimen 5 flux density
3 flaw
Figure 8 — Magnetic flow
8.3.3.4 Portable electromagnet (yoke)
The poles of an AC electromagnet (yoke) are placed in contact with the component surface as shown in
Figure 9. The testing area shall not be greater than that defined by a circle inscribed between the pole
pieces and shall exclude the zone immediately adjacent to the poles. An example of a suitable testing
area is shown in Figure 9.
Dimension in millimetres
Key
1 flaw
Figure 9 — Portable electromagnet (yoke)
The magnetization requirements defined in 8.1 can only be met with AC electromagnets. DC
electromagnets and permanent magnets may only be used by agreement at the time of enquiry and order.
8.3.3.5 Rigid coil
The component is placed within a current-carrying coil so that it is magnetized in the direction parallel
to the axis of the coil, as shown in Figure 10. Highest sensitivity is achieved for discontinuities elongated
perpendicular to the coil axis.
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