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BRITISH STANDARD

BS EN 1712:1997Incorporating Amendment No. 1

Non-destructive testing of welds — Ultrasonic testing of welded joints — Acceptance levels

The European Standard EN 1712:1997, with the incorporation of amendment A1:2002, has the status of a British Standard

ICS 25.160.40

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This British Standard, having been prepared under the direction of the Engineering Sector Board, was published under the authority of the Standards Board and comes into effect on 15 December 1997

© BSI 15 November 2002

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National forewordThis British Standard is the English language version of EN 1712:1997, including amendment A1:2002.

The start and finish of text introduced or altered by amendment is indicated in the text by tags ��. Tags indicating changes to CEN text carry the number of the amendment. For example, text altered by CEN amendment A1 is indicated by ��.

As agreed by CEN/TC 121/SC 5 resolution 134/2000 and in accordance with amendment A1:2002, the term “examination” has been replaced by “testing” throughout the document.

The UK participation in its preparation was entrusted by Technical Committee WEE/46, Non-destructive testing, to Technical Subcommittee WEE/46/-/13, Ultrasonic examination, which has the responsibility to:

A list of organizations represented on this subcommittee can be obtained on request to its secretary.

Cross-references

The British Standards which implement international or European publications referred to in this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.

This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.

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

— aid enquirers to understand the text; — present to the responsible European committee any enquiries on the

interpretation, or proposals for change, and keep the UK interests informed;

— monitor related international and European developments and promulgate them in the UK.

Summary of pages

This document comprises a front cover, an inside front cover, the EN title page,pages 2 to 11 and a back cover.

The BSI copyright notice displayed in this document indicates when the document was last issued.

Amendments issued since publication

Amd. No. Date Text affected

13991 15 November 2002 See national foreword

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EUROPEAN STANDARD

NORME EUROPÉENNE

EUROPÄISCHE NORM

EN 1712August 1997

+ A1May 2002

ICS 25.160.40

Descriptors: Welded joints, ferritic steels, non destructive tests, quality control, weld defects, ultrasonic tests, acceptability

English version

Non-destructive testing of welds —Ultrasonic testing of welded joints —

Acceptance levels(includes amendment A1:2002)

Contrôle non destructif des assemblages soudés —Contrôle par ultrasons des assemblages soudés —Niveaux d’acceptation(inclut l’amendement A1:2002)

Zerstörungsfreie Prüfung von Schweißverbindungen —Ultraschallprüfung von Schweißverbindungen —Zulässigkeitsgrenzen(enthält Änderung A1:2002)

This European Standard was approved by CEN on 1997-07-24. Amendment A1was approved by CEN on 2002-05-01. CEN members are bound to comply withthe CEN/CENELEC Internal Regulations which stipulate the conditions forgiving this European Standard the status of a national standard without anyalteration.

Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to anyCEN member.

This European Standard exists in three official versions (English, French,German). A version in any other language made by translation under theresponsibility of a CEN member into its own language and notified to theCentral Secretariat has the same 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.

CENEuropean Committee for Standardization

Comité Européen de NormalisationEuropäisches Komitee für Normung

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

© 1997 CEN — All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.

Ref. No. EN 1712:1997 + A1:2002 E

EN 1712:1997

Foreword

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

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 February 1998, and conflicting national standards shall be withdrawn at the latest by February 1998.

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

Foreword to amendment A1This document EN 1712:1997/A1:2002 has been prepared by Technical Committee CEN/TC 121, Welding, the Secretariat of which is held by DS.

This amendment to the European Standard EN 1712:1997 shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by November 2002, and conflicting national standards shall be withdrawn at the latest by November 2002.

This document has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association, and supports essential requirements of EU Directive(s).

For relationship with EU Directive(s), see informative Annex ZA, which is an integral part of this document.

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

Contents

PageForeword 21 Scope 32 Normative references 33 Evaluation of indications 33.1 General 33.2 Sensitivity setting 33.3 Reference level 43.4 Evaluation level 43.5 Recording level 43.6 Measurement of indication length 44 Acceptance levels 44.1 General 44.2 Longitudinal indications 54.3 Transverse indications 54.4 Indications detected by the tandem

technique 54.5 Linearly aligned and grouped indications 54.6 Cumulative length of acceptable

indications 55 Testing report 6Annex A (normative) Acceptance levels 7Annex B (normative) Fixed amplitude level technique 10Annex ZA (informative) Clauses of the European Standard addressing essential requirements or other provisions of EU directives 11

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1 Scope

�This European Standard specifies ultrasonic acceptance levels, 2 and 3, for full penetration welded joints in ferritic steels, which correspond to the quality levels B and C of EN 25817. Other acceptance levels can be used by specification.�

An acceptance level corresponding to level D of EN 25817 has not been included in this standard as ultrasonic testing is not recommended for this weld quality.

These acceptance levels are applicable to testing carried out in accordance with the standards referred to in EN 12062. �Text deleted.�

The standard is applicable to the testing of full penetration ferritic steel welds, with thicknesses from 8 mm up to 100 mm. It can also be used for other types of welds, materials and thicknesses above 100 mm, provided the tests have been performed with necessary consideration of the geometry and acoustical properties of the component and an adequate sensitivity can be employed to enable the acceptance levels of this standard to be applied. The nominal frequency of probes used in this European Standard is between 2 MHz and 5 MHz unless attenuation or requirements for higher resolution call for another frequency. The use of these acceptance levels in conjunction with frequencies outside this range needs to be considered carefully.

2 Normative referencesThis European Standard incorporates, by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the text and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies.

EN 1714, Non-destructive testing of welds — Ultrasonic testing of welded joints.

EN 12062, Non-destructive testing of welds — General rules for metallic materials.

EN 25817, Arc-welded joints in steel — Guidance on quality levels for imperfections.

3 Evaluation of indications

3.1 General

The evaluation of indications shall be performed on indications detected by testing performed in accordance with EN 1714.

3.2 Sensitivity setting

For each scanning technique the method for sensitivity setting shall be agreed upon prior to the testing and the same method should normally be used for subsequent testing.

The setting of sensitivity may be performed by:

— method 1: 3 mm diameter side drilled holes;— method 2: The distance gain size (DGS) system;— method 3: If a probe angle �70� is used for the thickness range 8 mm � t < 15 mm a rectangular notch with a depth of 1 mm may be used.

The length of the side drilled holes and notches shall be greater than the width of the sound beam measured at �20 dB. The width of the notch is not relevant in this application.

The acceptance levels for method 2 are based on the use of the following ultrasonic wave probes given in Table 1.

© BSI 15 November 2002 3

EN 1712:1997

Table 1 — Ultrasonic probe frequencies for method 2

If other probe frequencies are used the effect on the acceptance levels shall be considered and necessary corrections shall be made.

3.3 Reference level

One of the following methods for setting reference levels shall be used:

— method 1: The reference level is a distance-amplitude-curve (DAC-curve) for a 3 mm diameter side drilled hole;— method 2: The reference levels for transverse and longitudinal waves using the distance gain size (DGS) based on a disc shaped reflector (DSR) are given in Table A.3 and Table A.4 respectively;— method 3: The reference level is equal to a DAC curve for a 1 mm deep rectangular notch;— tandem testing: DDSR = 6 mm (for all thicknesses).

3.4 Evaluation level

All indications equal to or exceeding the following shall be evaluated:

— methods 1 and 3: Reference level �� 10 dB (33 % DAC);— method 2: Reference level � 4 dB, in accordance with Table A.3 and Table A.4 respectively;— tandem testing: DDSR = 6 mm (for all thicknesses).

3.5 Recording level

When recording levels are not otherwise specified, the following values shall be used:

— recording level for methods 1 and 3:— acceptance level 2: reference level � 6 dB (50 % DAC);— acceptance level 3: reference level – 2 dB (80 % DAC).

— recording level for method 2:— acceptance level 2: reference level;— acceptance level 3: reference level + 4 dB.

— recording level for tandem testing:— DDSR = 6 mm (for all thicknesses).

3.6 Measurement of indication length

The length of the indication shall be determined by measuring the distance along the length over which the echo amplitude is above the evaluation level, using the fixed amplitude level technique described in Annex B.

In order to achieve a more accurate measurement, a probe having a narrow beam width may be used or corrections for the influence of the beam width may be performed.

4 Acceptance levels

4.1 General

�The acceptance levels shall be related to the testing techniques (testing levels) as defined in EN 1714. Acceptance level 2 will normally require at least testing level B, and for acceptance level 3 at least testing level A. Any other relationship between acceptance levels and testing levels shall be defined by specification.�

The acceptance levels in this clause are valid for all testing levels and for all techniques, including testing with straight beam probes.

Thickness range, t Transverse wave probe frequency Longitudinal wave probe frequency

in mm in MHz in Mhz

8 � t < 15 4 4 to 5 15 � t < 40 2 to 4 2 to 5 40 � t � 100 2 2 to 5

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Indications are to be evaluated as longitudinal or transverse depending on the orientation of their major dimension. Where this distinction cannot be clearly made, the indication shall be classified as transverse if the echo amplitude obtained during the testing of transverse indications exceeds the echo amplitude obtained during the testing for longitudinal indications by 2 dB or more.

�Evaluation of indications may include discrimination between different imperfection types if defined in a specification.� In such case, the characterization as a planar indication may be used as the primary discrimination of an acceptable or rejectable indication. In this case all indications with echo amplitude above the evaluation level shall be characterized, and all that are characterized as planar shall be rejected.

For welds subject to fatigue loading, near surface acceptance levels may be �defined in a specification.�

4.2 Longitudinal indications

All indications with echo amplitudes and lengths exceeding the following limits are unacceptable:

Any indication with a length exceeding t, for the thickness range of 8 mm � t < 15 mm, or t/2 or 20 mm, whichever is the larger, for all other thickness ranges, shall be subject to further testing using additional probe angle(s), including the tandem technique where applicable. The final evaluation shall be based on the echo amplitude and length measured at the angle giving the maximum response.

4.3 Transverse indications

All indications exceeding the limits stated in 4.2 are unacceptable.

Transverse indications with echo amplitudes equal to or exceeding the evaluation level shall be classified by additional ultrasonic scanning, radiography or other testing method to determine their nature. Only indications that are isolated (i.e. maximum three per metre), whose length is less than 10 mm, are acceptable if they are planar. If they are non-planar the acceptance level for longitudinal indications shall apply.

4.4 Indications detected by the tandem technique

Indications detected by the tandem technique (longitudinal and transverse) shall be investigated further if their echo amplitudes exceed the recording level. Additional ultrasonic or radiographic testing shall be carried out in order to determine the type and size of the imperfections.

The acceptability of indications detected by the tandem technique is to be �defined by specification.�

4.5 Linearly aligned and grouped indications

Linearly aligned indications shall be considered as continuous if they are separated by a distance, dx, of less than twice the length of the longest indication. The total, combined length shall then be assessed against appropriate acceptance levels.

Linearly aligned indications shall satisfy the following:

dy � 5 mm, dz � 5 mm, see Figure 1

Adjacent indications grouped in this way shall not be used for further grouping with additional indications. Only discrete indications shall be subject to grouping.

After grouping, any recorded and accepted indications in the same cross-section and depth position (dz � 5 mm) shall be separated by a distance dy > 10 mm. Indications in the same lateral position (dy � 5 mm) shall be separated by a distance dz > 10 mm. Adjacent indications with smaller distances dy and dz are not acceptable.

4.6 Cumulative length of acceptable indications

For any length of weld equal to 6t, the maximum cumulative length of all individually acceptable indications above the recording levels shall not exceed 20 % of this length for acceptance level 2, or 30 % of this length for acceptance level 3.

– methods 1 and 3: Figure A.1 and Table A.1; – method 2: Figure A.2 and Table A.2.

© BSI 15 November 2002 5

EN 1712:1997

5 Testing report

All unacceptable and acceptable indications above the recording level shall be included in the testing report (see EN 1714).

Figure 1 — Geometric configurations for grouped indications

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Annex A (normative)Acceptance levels

Figure A.1 — Acceptance levels 2 and 3 for methods 1 and 3

© BSI 15 November 2002 7

EN 1712:1997

Figure A.2 — Acceptance levels 2 and 3 for method 2

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Table A.1 — Acceptance levels 2 and 3 for methods 1 and 3

Table A.2 — Acceptance levels 2 and 3 for method 2

Table A.3 — Reference levels for angle beam scanning with transverse waves for method 2 (DGS)

Table A.4 — Reference levels for longitudinal waves for method 2 (DGS)

8 mm � t < 15 mm Indication length, l (mm) Max. permitted echo amplitude l � t Reference level l > t Reference level � 6 dB 15 mm � t � 100 mm Indication length, l (mm) Max. permitted echo amplitude l � 0,5t Reference level + 4 dB 0,5t < l � t Reference level � 2 dB l > t Reference level �� 6 dB Evaluation level: Reference level � 10 dBRecording levels: Acceptance level 2 = Reference level �� 6 dB

Acceptance level 3 = Reference level � 2 dB

8 mm � t < 15 mm Indication length, l (mm) Max. permitted echo amplitude l � t Reference level + 6 dB l > t Reference level 15 mm � t � 100 mm Indication length, l (mm) Max. permitted echo amplitude l � 0,5t Reference level +10 dB 0,5t < l � t Reference level + 4 dB l > t Reference level Evaluation level: Reference level � 4 dB Recording levels: Acceptance level 2 = Reference level

Acceptance level 3 = Reference level + 4 dB

Nominal probe frequency(MHz)

Thickness of parent material (mm)

8 � t < 15 15 � t < 40 40 � t � 100 1,5 to 2,5 — DDSR = 2 mm DDSR = 3 mm 3 to 5 DDSR = 1 mm DDSR = 1,5 mm —

Nominal probe frequency (MHz)

Thickness of parent material (mm)

8 � t < 15 15 � t < 40 40 � t � 100 1,5 to 2,5 — DDSR = 2 mm DDSR = 3 mm 3 to 5 DDSR = 2 mm DDSR = 2 mm DDSR = 3 mm

© BSI 15 November 2002 9

EN 1712:1997

Annex B (normative)Fixed amplitude level technique

The technique measures the lateral dimensions of an indication over which the echo is equal to or greater than the evaluation level.

To make a measurement the beam is scanned over the indications, and the probe position and beam path range, at which the echo has fallen to the evaluation level are noted (positions 1 and 2 of Figure B.1).

The lateral dimension, l, is then determined by the distance of the positions 1 and 2.

Figure B.1 — Fixed amplitude level technique using the beam axis

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�Annex ZA (informative)Clauses of this European Standard addressing essential requirements or other provisions of EU directives

This European Standard has been prepared under a mandate given to CEN by the European Commission and the European Free Trade Association and supports essential requirements of EU 97/23/EC of the European Parliament and the Council of 29 May 1997 on the approximation of the laws of the Member States concerning pressure equipment.

WARNING Other requirements and other EU Directives may be applicable to the product(s) falling within the scope of this standard.

The following clauses of this standard as detailed in Table ZA.1 and Table ZA.2, are likely to support requirements of the Directives 97/23/EC and 87/404/EEC.

Compliance with these clauses of this standard provides one with means of conforming to the specific essential requirements of the Directives concerned and associated EFTA regulations.

Table ZA.1 — Correspondence between this European Standard and Directive 97/23/EC

Table ZA.2 — Correspondence between this European Standard and Directive 87/404/EEC

�

Clauses/subclauses of this European Standard

Essential requirements of Directive 97/23/EC

Qualifying remarks/notes

All Annex I, 3.1.2 Non-destructive tests

Clauses/subclauses of this European Standard

Essential requirements of Directive 87/404/EEC

Qualifying remarks/notes

All Annex I, 3.2 Welds on pressurized parts

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