|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||

BRITISH STANDARD BS EN1290:1998

The European Standard EN 1290:1998 has the status of aBritish Standard

ICS 25.160.40

NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW

Non-destructive examinationof welds Ð Magnetic particleexamination of welds

This British Standard, havingbeen prepared under thedirection of the EngineeringSector Board, was publishedunder the authority of theStandards Board and comes intoeffect on 15 June 1998

BSI 1998

ISBN 0 580 29630 X

BS EN 1290:1998

Amendments issued since publication

Amd. No. Date Text affected

National foreword

This British Standard is the English language version of EN 1290:1998.

The UK participation in its preparation was entrusted to Technical CommitteeWEE/46, Non-destructive examination, which has the responsibility to:

Ð aid enquirers to understand the text;

Ð present to the responsible European committee any enquiries on theinterpretation, or proposals for change, and keep the UK interests informed;

Ð monitor related international and European developments and promulgatethem in the UK.

A list of organizations represented on this committee can be obtained on request toits secretary.

Cross-references

The British Standards which implement international or European publicationsreferred to in this document may be found in the BSI Standards Catalogue under thesection entitled ªInternational Standards Correspondence Indexº, or by using theªFindº facility of the BSI Standards Electronic Catalogue.

A British Standard does not purport to include all the necessary provisions of acontract. Users of British Standards are responsible for their correct application.

Compliance with a British Standard does not of itself confer immunityfrom legal obligations.

Summary of pages

This document comprises a front cover, an inside front cover, the EN title page,pages 2 to 13 and a back cover.

CENEuropean Committee for Standardization

Comite EuropeÂen de Normalisation

EuropaÈisches Komitee fuÈ r Normung

Central Secretariat: rue de Stassart 36, B-1050 Brussels

1998 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN nationalMembers.

Ref. No. EN 1290:1998 E

EUROPEAN STANDARD EN 1290

NORME EUROPEÂ ENNE

EUROPAÈ ISCHE NORM February 1998

ICS 25.160.40

Descriptors: Welded joints, ferromagnetic materials, quality control, non-destructive tests, detection, weld defects,magnetic particle testing, surface treatment

English version

Non-destructive examination of welds Ð Magnetic particleexamination of welds

Controà le non destructif des assemblagessoudeÂs Ð Controà le par magneÂtoscopie desassemblages soudeÂs

ZerstoÈrungsfreie PruÈfung vonSchweiûverbindungen Ð MagnetpulverpruÈfungvon Schweiûverbindungen

This European Standard was approved by CEN on 26 January 1998.

CEN members are bound to comply with the CEN/CENELEC Internal Regulationswhich stipulate the conditions for giving this European Standard the status of anational standard without any alteration. Up-to-date lists and bibliographicalreferences concerning such national standards may be obtained on application tothe Central Secretariat 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 aCEN member into its own language and notified to the Central Secretariat has thesame status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, CzechRepublic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland andUnited Kingdom.

Page 2EN 1290:1998

BSI 1998

Foreword

This European Standard has been prepared byTechnical Committee CEN/TC 121, Welding, thesecretariat of which is held by DS.

This European Standard shall be given the status of anational standard, either by publication of an identicaltext or by endorsement, at the latest by August 1998,and conflicting national standards shall be withdrawnat the latest by August 1998.

This European Standard has been prepared under amandate given to CEN by the European Commissionand the European Free Trade Association, andsupports essential requirements of EU Directive(s).

According to the CEN/CENELEC Internal Regulations,the national standards organizations of the followingcountries are bound to implement this EuropeanStandard: Austria, Belgium, Czech Republic, Denmark,Finland, France, Germany, Greece, Iceland, Ireland,Italy, Luxembourg, Netherlands, Norway, Portugal,Spain, Sweden, Switzerland and the United Kingdom.

Contents

Page

Foreword 2

1 Scope 3

2 Normative references 3

3 Definitions 3

4 Safety precautions 3

5 General 3

5.1 Information 3

5.2 Personnel qualification 3

5.3 Surface conditions and preparation 4

5.4 Magnetizing 4

5.5 Application techniques 4

5.6 Detecting media 11

5.7 Viewing conditions 11

5.8 Application of detecting media 11

5.9 Overall performance test 11

5.10 False indications 11

5.11 Recording of indications 11

5.12 Demagnetization 11

5.13 Examination report 12

Annex A (informative) Sensitivity aspects 13

Page 3EN 1290:1998

BSI 1998

1 ScopeThis standard specifies magnetic particle examinationtechniques for the detection of surface imperfections inferromagnetic welds, including the heat-affected zones,using the magnetic method. Techniques recommendedare suitable for most welding processes and jointconfigurations. Variations to the basic techniques thatwill provide a higher or lower examination sensitivityare described in annex A.

Techniques for examination of welds, with geometriesin accordance with those shown in Tables 1, 2 and 3,can be used directly from this standard.

Acceptance levels for indications are describedin EN 1291.

2 Normative referencesThis European Standard incorporates by dated orundated reference, provisions from other publications.These normative references are cited at theappropriate places in the text and the publications arelisted hereafter. For dated references, subsequentamendments to or revisions of any of thesepublications apply to this European Standard onlywhen incorporated in it by amendment or revision. Forundated references the latest edition of the publicationreferred to applies.

EN 473, Qualification and certification of NDTpersonnel Ð General principles.

EN 1291, Non-destructive examination of welds ÐMagnetic particle testing of welds Ð Acceptance levels.

prEN 1956, Non-destructive testing ÐPenetrant testing and magnetic particle testing ÐViewing conditions.

EN 12062, Non-destructive examination of welds ÐGeneral rules for metallic materials.

3 DefinitionsFor the purposes of this standard, the definitions givenin EN 12062 apply.

4 Safety precautionsEuropean, national and local safety and environmentalprotection regulation shall be observed at all times.

Special consideration shall be given to toxic flammableand/or volatile materials, electrical safety and unfilteredUV radiation.

5 General

5.1 Information

5.1.1 Contractual agreement

Before carrying out magnetic particle examination, thefollowing items, if applicable, shall be agreed betweenthe contracting parties:

a) specific examination procedure;

b) certification requirements for NDT personnel;

c) extent of coverage;

d) state of manufacture;

e) examination techniques to be used;

f) overall performance test;

g) demagnetization;

h) acceptance level;

i) action necessary for unacceptable indications.

5.1.2 Additional information

Prior to examination, the following additionalinformation can be required:

a) type and designation of the parent and weldmaterials;

b) welding process;

c) location and extent of welds to be examined;

d) joint preparation and dimensions;

e) location and extent of any repairs;

f) post-weld treatment (if any);

g) surface conditions.

Operators can ask for further information that could behelpful in determining the nature of any indicationsdetected.

5.2 Personnel qualification

Personnel performing non-destructive examination inaccordance with this standard shall be qualified to anappropriate level in accordance with EN 473 or anequivalent standard at an appropriate level in therelevant industrial sector.

Page 4EN 1290:1998

BSI 1998

5.3 Surface conditions and preparation

Areas to be examined shall be free from scale, oil,grease, weld spatter, machining marks, dirt, heavy andloose paint, and any other foreign matter that canaffect sensitivity.

It can be necessary to improve the surface condition,e.g. by abrasive paper or local grinding, to permitaccurate interpretation of indications.

Cleaning and preparation of surfaces shall not bedetrimental to the material, the surface finish or themagnetic examination media.

5.4 Magnetizing

5.4.1 Magnetizing equipment

Unless otherwise agreed, the following types ofalternating-current magnetizing equipment shall beused:

a) electromagnetic yokes;

b) current flow equipment with prods;

c) adjacent or threading conductors, or coiltechniques.

The use of direct-current magnetization or permanentmagnets shall be by agreement between thecontracting parties.

The magnetizing equipment used shall comply with therequirements of relevant European Standards. Prior tothe publication of European Standards related to thesubject, the corresponding national standards may beused.

Where prods are used, precautions shall be taken tominimize overheating, burning or arcing at the contacttips. Removal of arc burns shall be carried out wherenecessary. The affected area shall be tested by asuitable method to ensure the integrity of the surface.

5.4.2 Verification of magnetization

For most weldable ferromagnetic materials, atangential magnetic field strengthof 2 kA/m to 6 kA/m (r.m.s.) is recommended.

Verification of the magnetic field strength shall becarried out using one of the following methods:

a) a component containing fine natural or artificialimperfections in the least favourable locations;

b) measurement of the tangential field strength asclose as possible to the surface using a Hall effectprobe. The appropriate tangential field strength canbe difficult to measure close to abrupt changes inthe shape of a component, or where flux leaves thesurface of a component;

c) calculation of the approximate tangential fieldstrength. The calculations form the basis of thecurrent values specified in Tables 2 and 3;

d) other methods based on established principles.

NOTE Flux indicators, placed in contact with the surface underexamination, can provide a guide to the magnitude and directionof the tangential field, but should not be used to verify that thefield strength is acceptable.

5.5 Application techniques

5.5.1 Field directions and examination area

The detectability of an imperfection depends on theangle of its major axis with respect to the direction ofthe magnetic field. This is explained for one directionof magnetization in Figure 1.

To ensure detection of imperfections in all orientations,the welds shall be magnetized in two directionsapproximately perpendicular to each other with amaximum deviation of 308. This can be achieved usingone or more magnetization methods.

Examination in only one field direction shall be byagreement between the contracting parties.

When examination involves the use of yokes or prods,there will be an area of the component, in the vicinityof each pole piece or tip, that will be impossible toexamine due to excessive magnetic field strength,usually shown by furring of particles.

Care shall be taken to ensure adequate overlap of theexamination areas as shown in Figures 2 and 3.

5.5.2 Typical magnetic examination techniques

Applications of magnetic particle examinationtechniques to common weld joint configurations areshown in Tables 1, 2 and 3. Values are given forguidance purposes only. Where possible, the samedirections of magnetization, and field overlaps, shouldbe used for other weld geometries to be tested. Thedimension, d, the flux current path in the material,shall be greater than or equal to the width of the weldand the heat-affected zone +50 mm, and in all cases theweld and the heat-affected zone shall be included inthe effective area. The approximate angle ofmagnetization related to the weld direction shall bespecified.

Page 5EN 1290:1998

BSI 1998

1 Magnetic field direction

2 Optimum sensitivity

3 Reducing sensitivity

4 Insufficient sensitivity

a is the angle between the magnetic field and the direction of the imperfection

amin is the minimum angle for imperfection detection

ai is an example of imperfection orientation

Figure 1 Ð Directions of detectable imperfections

Page 6EN 1290:1998

BSI 1998

Dimensions in millimetres

Figure 2 Ð Examples of effective examination area (shaded) for magnetizing withyokes and prods

Page 7EN 1290:1998

BSI 1998

1 Effective area2 Overlap

Figure 3 Ð Overlap of effective areas

Page 8EN 1290:1998

BSI 1998

Table 1 Ð Typical magnetizing techniques for yokes

Dimensions in millimetres

d$ 75

b# d/2

b ≈ 908

d1$ 75

b1# d1/2

b2# d22 50

d2$ 75

d1$ 75

d2 > 75

b1# d1/2

b2# d22 50

d1$ 75

d2$ 75

b1# d1/2

b2# d22 50

Page 9EN 1290:1998

BSI 1998

Table 2 Ð Typical magnetizing techniques for prods, using a magnetizing current$ 5 A/mm (r.m.s.) prod spacing

Dimensions in millimetres

d$ 75

b# d/2

b ≈ 908

d$ 75

b# d/2

d$ 75

b# d/2

d$ 75

b# d/2

Page 10EN 1290:1998

BSI 1998

Table 3 Ð Typical magnetizing techniques for flexible cables or coils

Dimensions in millimetres

For longitudinal cracks

20# a# 50

NI$ 8D

For longitudinal cracks

20# a# 50

NI$ 8D

For longitudinal cracks

20# a# 50

NI$ 8D

N is the number of turns;

I is the current (r.m.s.);

a is the distance between weld and coil or cable.

Page 11EN 1290:1998

BSI 1998

1) For metal-cutting processes, a typical residual field strength value of H# 0,4 kA/m is recommended.

5.6 Detecting media

5.6.1 General

Detection media may be either in dry powder or liquidform and shall comply with the requirements ofrelevant European Standards. Prior to the publicationof European Standards related to the subject, thecorresponding national standards may be used.

5.6.2 Verification of detecting media performance

Verification of the detecting media shall be carried outperiodically to confirm continuing satisfactoryperformance.

The verification shall be carried out on componentshaving known or artificial surface imperfections, or onpre-magnetized reference pieces.

Indications obtained with the medium to be verifiedshall be compared against those obtained from amedium having a known and acceptable performance.For this purpose the reference indications may be:

a) real imperfections;

b) photograph(s); or

c) replica(s).

5.7 Viewing conditions

The viewing conditions shall meet the requirementsof prEN 1956.

5.8 Application of detecting media

After the object has been prepared for examination,magnetic detecting medium shall be applied byspraying, flooding or dusting immediately prior to andduring the magnetization. Following this, time shall beallowed for indications to form before removal of themagnetic field.

When magnetic suspensions are used, the magneticfield shall be maintained within the object until themajority of the suspension carrier liquid has drainedaway from the examination surface. This will preventany indications being washed away.

Depending on the material being examined, its surfacecondition and magnetic permeability, indications willnormally remain on the surface even after removal ofthe magnetic field, due to residual magnetism withinthe part. However, the presence of residual magnetismshall not be presumed; post-evaluation techniques afterremoval of the prime magnetic field source can bepermitted only when a component has been proven byan overall performance test to retain magneticindications.

5.9 Overall performance test

Where agreed between the contracting parties, anoverall performance test of the system sensitivity, foreach specific procedure shall be carried out on site.The test shall be designed to ensure a properfunctioning of the entire chain of parameters, includingthe equipment, the magnetic field strength anddirection, surface characteristics, detecting media andillumination.

The most reliable test is to use representative testpieces containing real imperfections of known type,location, size and size distribution. Where these are notavailable, fabricated test pieces with artificialimperfections, or flux shunting indicators of the crosstype or shim type may be used. The test pieces shallbe demagnetized and free from indications resultingfrom previous tests.

5.10 False indications

False indications which may mask relevant indicationscan arise for many reasons, e.g. undercut and changesin magnetic permeability, i.e. the heat-affected zone.Where masking is suspected, the examination surfaceshall be dressed, or suitable alternative examinationmethods can be used.

5.11 Recording of indications

Indications can be recorded in one or more of thefollowing ways by using:

a) description in writing;

b) sketches;

c) photography;

d) transparent adhesive tape;

e) transparent varnish for ªfreezingº the indicationon the surface tested;

f) strippable contrast aids;

g) video recording;

h) epoxy or chemical magnetic particle mixtures;

i) magnetic tapes;

j) electronic scanning.

5.12 Demagnetization

After examination of welds with alternating current,residual magnetization will normally be low and therewill generally be no need for demagnetization of theobject under examination.

If required, the demagnetization shall be carried out bya method and to a level agreed between thecontracting parties.1)

Page 12EN 1290:1998

BSI 1998

5.13 Examination report

An examination report shall be prepared.

Where prior agreement has not been reached oninformation that will be included in the examinationreport, the following list should be used for facilitatinga reproducible examination:

a) name of the company carrying out theexamination;

b) the object examined;

c) date of examination;

d) parent and weld materials;

e) post-weld heat treatment;

f) type of joint;

g) material thickness;

h) welding process;

i) temperature of the test object, if outside normalambient temperature;

j) identification of examination procedure anddescription of the parameters used, including:

Ð type of magnetization;

Ð type of current;

Ð detection media;

Ð viewing conditions;

k) details and results of the overall performance test,where applicable;

l) acceptance levels;

m) description and location of all recordableindications;

n) examination results with reference to acceptancelevel;

o) names, relevant qualification and signatures ofpersonnel who carried out the examination.

Page 13EN 1290:1998

BSI 1998

Annex A (informative)

Sensitivity aspects

A.1 Surface conditions and preparation

The maximum examination sensitivity that can beachieved by any magnetic examination method isdependent on many variables but can be seriouslyaffected by the surface roughness of the object andany irregularities present. In some cases it can benecessary to:

Ð dress undercut and surface irregularities bygrinding;

Ð remove or reduce the weld reinforcement.

Surfaces covered with a thin non-magnetic paint, e.g. aprimer may also be examined, provided that the paintsurface is unbroken and the thickness of the coatingdoes not exceed 50 mm. Above this thickness, thesensitivity of the method decreases and can bespecifically determined before proceeding with theexamination.

A.2 Magnetizing equipment characteristics

The use of alternating current gives the best sensitivityfor detecting surface imperfections.

Yokes produce an adequate magnetic field in simplebutt-welds, but where the flux is reduced by gaps orthe path is excessive through the object, as in T-buttjoints, a reduction of sensitivity can occur.

For complex joint configurations, e.g. fillet welds withan inclined angle of less than 908, examination usingyokes might be inadequate. In these cases, prods orcable wrapping with current flow will prove moresuitable.

A.3 Magnetic field strength and permeability

The field strength required to produce an indicationstrong enough to be detected during magnetic particleexamination is dependent mainly on the magneticpermeability of the object.

Generally, magnetic permeability is high in softermagnetic materials, e.g. low-alloy steels, and low inharder magnetic materials, e.g. martensitic steels.Because permeability is a function of the magnetizingcurrent, low-permeability materials usually requireapplication of a higher magnetization value than softeralloys, to produce the same flux density. It is essential,therefore, to establish that flux density values areadequate before beginning the magnetic particleexamination.

A.4 Detecting media

Magnetic particle suspensions will usually give a highersensitivity for detecting surface imperfections than drypowders.

Fluorescent magnetic detection media usually give ahigher test sensitivity than colour-contrast media,because of the higher contrast between the darkenedbackground and the fluorescent indication. Thesensitivity of the fluorescent method will, nevertheless,decrease in proportion to any increase in theroughness of the surface to which magnetic particlesadhere, and can cause a disturbing backgroundfluorescence.

Where the background illumination cannot beadequately lowered, or where background fluorescenceis disturbing, coloured detection media in conjunctionwith the smoothing effect of a contrast aid will usuallygive a better sensitivity.

BSI389 Chiswick High RoadLondonW4 4AL

|||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||

BSI Ð British Standards Institution

BSI is the independent national body responsible for preparing British Standards. Itpresents the UK view on standards in Europe and at the international level. It isincorporated by Royal Charter.

Revisions

British Standards are updated by amendment or revision. Users of British Standardsshould make sure that they possess the latest amendments or editions.

It is the constant aim of BSI to improve the quality of our products and services. Wewould be grateful if anyone finding an inaccuracy or ambiguity while using thisBritish Standard would inform the Secretary of the technical committee responsible,the identity of which can be found on the inside front cover. Tel: 020 8996 9000.Fax: 020 8996 7400.

BSI offers members an individual updating service called PLUS which ensures thatsubscribers automatically receive the latest editions of standards.

Buying standards

Orders for all BSI, international and foreign standards publications should beaddressed to Customer Services. Tel: 020 8996 9001. Fax: 020 8996 7001.

In response to orders for international standards, it is BSI policy to supply the BSIimplementation of those that have been published as British Standards, unlessotherwise requested.

Information on standards

BSI provides a wide range of information on national, European and internationalstandards through its Library and its Technical Help to Exporters Service. VariousBSI electronic information services are also available which give details on all itsproducts and services. Contact the Information Centre. Tel: 020 8996 7111.Fax: 020 8996 7048.

Subscribing members of BSI are kept up to date with standards developments andreceive substantial discounts on the purchase price of standards. For details ofthese and other benefits contact Membership Administration. Tel: 020 8996 7002.Fax: 020 8996 7001.

Copyright

Copyright subsists in all BSI publications. BSI also holds the copyright, in the UK, ofthe publications of the international standardization bodies. Except as permittedunder the Copyright, Designs and Patents Act 1988 no extract may be reproduced,stored in a retrieval system or transmitted in any form or by any means ± electronic,photocopying, recording or otherwise ± without prior written permission from BSI.

This does not preclude the free use, in the course of implementing the standard, ofnecessary details such as symbols, and size, type or grade designations. If thesedetails are to be used for any other purpose than implementation then the priorwritten permission of BSI must be obtained.

If permission is granted, the terms may include royalty payments or a licensingagreement. Details and advice can be obtained from the Copyright Manager.Tel: 020 8996 7070.