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ПІДТВЕРДЖУВАЛЬНЕ ПОВІДОМЛЕННЯ

Державне підприємство

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EN 12680-1:2003

Founding -

Ultrasonic examination - Part 1: Steel castings for general purposes

прийнято як національний стандарт
методом «підтвердження» за позначенням

ДСТУ EN 12680-1:2015 (EN 12680-1:2003, IDT)

ЛИТВО

Ультразвуковий контроль. Частина 1. Відливки зі сталі загальної
призначеності

Копію цього стандарту можна отримати
у Національному фонді нормативних документів

З наданням чинності від 2016—01-01

EN 12680-1

January 2003

EUROPEAN STANDARD

NORME EUROPEENNE

EUROPAISCHE NORM

ICS 77.040.20

English version

Founding - Ultrasonic examination - Part 1: Steel castings for
general purposes

Fonderie - Controle par ultrasons - Partie 1: Pieces
moulees en acier pour usages generaux

GieBereiwesen - Ultraschallprufung - Teil 1:
StahlgussstOcke fOr allgemeine Verwendun

g

This European Standard was approved by CEN on 21 November 2002.

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 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 Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Luxembourg, Malta, Netherlands, Norway, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom.

EUROPEAN COMMITTEE FOR STANDARDIZATION
СОМІТЁ EUROPEEN DE NORMALISATION

EUROPAISCHES KOMITEE FUR NORMUNG

Management Centre: rue de Stassart, 36 B-1050 Brussels

© 2003 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members.

Contents

page

Foreword 3

1. Scope 4

2. Normative references 4

3. Terms and definitions 4

4. Requirements 5

   1. Order information 5

   2. Extent of examination 6

   3. Maximum permissible size of discontinuities 6

   4. Personnel qualification 6

   5. Wall section zones 7

   6. Severity levels 7

5. Examination 7

   1. Principles 7

   2. Material 7

   3. Equipment and coupling medium 8

   4. Preparation of casting surfaces for examination 8

   5. Examination procedure 9

   6. Examination report 11

1. (informative) Sound-beam diameters 19

2. (informative) Types of indications 21

Bibliography 33Foreword

This document (EN 12680-1:2003) has been prepared by Technical Committee CEN/TC 190 "Foundry Technol­ogy", the secretariat of which is held by DIN.

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 July 2003, and conflicting national standards shall be withdrawn at the latest by July 2003.

Within its programme of work, Technical Committee CEN/TC 190 requested CEN/TC 190/WG 4.10 “Inner defects" to prepare the following standard: ,

EN 12680-1, Founding — Ultrasonic examination — Part 1: Steel castings for general purposes.

This is one of three European Standards for ultrasonic examination. The other standards are:

EN 12680-2, Founding Ultrasonic examination —. Part 2: Steel castings for highly stressed components.

EN 12680-3, Founding Ultrasonic examination — Part3: Spheroidal graphite cast iron castings.

Annexes A and В are informative.

1. 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.Scope

This European Standard specifies the requirements for the ultrasonic examination of steel castings (with ferritic structure) for general purposes and the methods for determining internal discontinuities by the pulse-echo tech­nique.

This European Standard applies to the ultrasonic examination of steel castings which have usually received a grain refining heat treatment and which have wall thicknesses up to and including 600 mm.

For greater wall thicknesses, special agreements apply with respect to test procedure and recording levels. t

This European Standard does not apply to austenitic steels and joint welds.

2. Normative references

This 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 (including amendments).

EN 583-1, Non-destructive testing ~~ Ultrasonic examination Part 1: General principles.

EN 583-2, Non-destructive testing — Ultrasonic examination — Part 2: Sensitivity and range setting.

EN 583-5, Non-destructive testing — Ultrasonic examination Part 5: Characterization and sizing of discon­tinuities.

EN 12223, Non-destructive testing ~~~ Ultrasonic examination Specification for calibration block No. 1.

EN 12668-1, Non-destructive testing — Characterization and verification of ultrasonic examination equipment —. Part 1: Instruments.

EN 12668-2, Non-destructive testing Characterization and verification of ultrasonic examination equipment — Part 2: Probes.

EN 12668-3, Non-destructive testing — Characterization and verification of ultrasonic examination equipment — Part 3: Combined equipment.

EN 27963, Welds in steel Calibration block No. 2 for ultrasonic examination of welds (ISO 7963:1985).

3. Terms and definitions

For the purposes of this European Standard, the following terms and definitions apply.

NOTE Other terms and definitions used in this European Standard are given in EN 583-1, EN 583-2, EN 583-5 and EN 1330-4.

reference discontinuity echo size

smallest indication to be recorded during the assessment phase of an ultrasonic examination, usually expressed as an equivalent flat-bottomed hole diameter

point discontinuity

discontinuity, the dimensions of which are smaller than or equal to the sound-beam width

NOTE Dimensions in this standard relate to length, width and/or dimension in through-wall direction.

complex discontinuity

discontinuity, the dimensions of which are larger than the sound-beam width

NOTE Dimensions in this standard relate to length, width and/or dimension in through-wall direction.

planar discontinuity

discontinuity having two measurable dimensions

volumetric discontinuity

discontinuity having three measurable dimensions

special rim zone

outer rim zone part with special requirements (for e.g. machined surfaces, higher stresses, sealing surfaces)

production welding

any welding carried out during manufacturing before final delivery to the purchaser

joint welding

production welding used to assemble components together to obtain an integral unit

finishing welding

production welding carried out in order to ensure the agreed quality of the casting

4. Requirements

   1. Order information

T-e following information shall be available at the time of enquiry and order (see also EN 583-1):

• the areas of the casting and the number or percentage of castings to which the ultrasonic examination require- "'•ents apply (examination volume, extent of examination);

• ne severity level to be applied to the various zones or areas of the casting (acceptance criteria);

• •wjfrements for a written examination procedure;

• are-T-er there are any additional requirements for the examination procedure, see also 5.5.1.

The casting shall be examined so that the agreed areas are totally covered (insofar as this is possible from the shape of the casting) by the use of the best applicable examination technique.

For wall thicknesses greater than 600 mm, agreement shall be made between the parties concerned on the exami­nation procedure and also on the recording and acceptance levels.

The limits of acceptance for planar discontinuities are given in Figure 1.

Indications with measurable dimensions are not permissible as severity level 1.

The largest dimension in through-wall direction shall not exceed 10% of wall thickness, except indications with a measurable length < 10 mm. Such indications shall not exceed a dimension in through-wall direction of 25 % of wall thickness or 20 mm.

The greatest distance between indications as criterion for evaluation as single indication or indication area perpen­dicular or lateral to the surface shall be 10 mm.

For an area with measurable length and non-measurable dimension in through-wall direction, this non-measurable dimension shall be taken as 3 mm and the area be calculated:

4 = 3x£ (1)

where

• A is the area of indication expressed in square millimetres;

• 3 is the taken width in millimetres;

• L is the measurable length expressed in millimetres.

The limits of acceptance for volumetric discontinuities are given in Table 1. Any discontinuity exceeding one of the criteria shall be considered as unacceptable.

Unless otherwise agreed by the time of enquiry and order, when, after conducting the radiographic and the ultra­sonic examination in combination, it has been demonstrated that a discontinuity is situated in the core zone, this additional information makes the discontinuity acceptable at one level less severe, e.g. severity level 3 instead of 2 for radiographic examination, see EN 1559-2.

It is assumed that ultrasonic examination is performed by qualified and capable personnel. In order to prove this qualification, it is recommended to certify personnel in accordance with EN 473.

The wall section shall be divided into zones as shown in Figure 2. These sections relate to the dimensions of the casting ready for assembly (finish machined).

If the purchaser specifies different severity levels in different areas of the same casting, all of these areas shall be clearly identified on the purchaser's drawing and shall include:

• all necessary dimensions for accurate location of zones;

• the full extent of all weld preparations and the thickness of any special rim zone.

Severity level 1 is only applied to weld preparations and special rim zones.

Unless other requirements have been agreed by the time of acceptance of the order, for finishing welds, the re­quirements for the parent metal shall apply.

5 Examination

The principles of ultrasonic examination given in EN 583-1, EN 583-2 and EN 583-5 shall apply.

The suitability of material for ultrasonic examination is assessed by comparison with the echo height of a reference reflector (usually the first backwall echo) and the noise signal. This assessment shall be carried out on selected casting areas which are representative of the surface finish and of the total thickness range. The assessment areas shall have parallel surfaces.

The reference echo height according to Table 2 shall be at least 6 dB above the noise signal.

If the echo height of this smallest detectable flat-bottomed or equivalent side-drilled hole diameter at the end of the test range to be assessed is less than 6 dB above the grass level, then the ultrasonic testability is reduced. In this case, the flat-bottomed or side-drilled hole diameter which can be detected with a signal-noise ratio of at least 6 dB shall be noted in the test report and the additional procedure shall be agreed between the manufacturer and the purchaser.

NOTE For the definition of an adequate flat-bottomed hole size, the distance gain size system (DGS) or a test block of identical material, heat treatment condition and section thickness containing flat-bottomed holes with a diameter according to Table 2 or equivalent side-drilled holes, can be used. The following formula is used for converting the flat-bottomed hole di­ameter into the side-drilled hole diameter:

_ 4,935 x £>p_BH

- з Ю

Л X 5

where

D_q is the side-drilled hole diameter in millimetres;

D_fbh is the flat-bottomed hole diameter in millimetres;

Л is the wave length in millimetres;

is the path length in millimetres.

The formula is applicable for D_Q> 2 A and s > 5 x near-field length and is only defined for single element probes.

The ultrasonic instrument shall meet the requirements given in EN 12668-1 and shall have the following character­istics:

• range setting, from at least 10 mm to 2 m continuously selectable, for longitudinal and transverse waves transmitted in steel;

• gain, adjustable in 2 dB maximum steps over a range of at least 80 dB with a measuring accuracy of 1 dB;

• time-base and vertical linearities less than 5 % of the adjustment range of the screen;

• suitability at least for nominal frequencies from 1 MHz up to and including 5 MHz in pulse-echo technique with single-crystal and twin-crystal probes.

The probes and transducer frequencies shall be as given in EN 12668-2 and EN 12668-3 with the following excep­tions:

• nominal frequencies shall be in the range 1 MHz to 5 MHz;

• for oblique incidence, angle probes with angles between 35° and 70° shall be used.

NOTE Normal or angle probes can be used for the examination of steel castings. The type of probe used depends on the geometry of the casting and the type of discontinuity to be detected.

For examining zones close to the surface, twin-crystal probes (normal or angle) should be preferred.

The ultrasonic examination equipment shall be checked regularly by the operator according to EN 12668-3.

A coupling medium in accordance with EN 583-1 shall be used. The coupling medium shall wet the examination area to ensure satisfactory sound transmission. The same coupling medium shall be used for calibration and all subsequent examination operations.

NOTE The sound transmission can be checked by ensuring one or more stable backwall echoes in areas with parallel surfaces.

For the preparation of casting surfaces for examination see EN 583-1.

The casting surfaces to be examined shall be such that satisfactory coupling with the probe can be achieved.

In the case of single-crystal probes, satisfactory coupling can be achieved if the condition of the surfaces to be ex­amined corresponds at least to the limit comparator 4 S1 or 4 S2 according to EN 1370.

The roughness of any machined surface to be examined shall be R_a< 12,5 pm.

For special techniques, higher surface qualities such as 2 S1,2 S2 (see EN 1370) and R_a< 6,3 pm can be neces­sary.

Because the choice of both the direction of incidence and suitable probes largely depends on the shape of the casting or on the possible casting discontinuities or on the possible discontinuities from finishing welding, the appli­cable examination procedure shall be specified by the manufacturer of the casting. In special cases, specific agreements can be made.

If possible, the areas to be tested shall be examined from both sides. When testing from one side only, short-range resolving probes shall be used additionally for the detection of discontinuities close to the surface. Testing with twin-crystal probes is only adequate for wall thicknesses up to 50 mm.

Additionally, when not otherwise agreed between the purchaser and the manufacturer, for all castings, twin-crystal normal and/or angle probes shall be used to examine the following areas up to a depth of 50 mm:

• critical areas, e.g. fillets, changes in cross-section, areas with external chills;

• finishing welds;

• weld preparation areas as specified in the order;

• special rim zones, as specified in the order, critical for the performance of the casting.

Finishing welds which are deeper than 50 mm shall be subject to supplementary examination with other suitable angle probes.

For angle probes with angles over 60°, the sound beam path shall not exceed 150 mm.

Complete coverage of all areas specified for examination shall be conducted by carrying out systematically over­lapping scans.

The scanning rate shall not exceed 150 mm/s.

Range setting shall be carried out in accordance with EN 583-2 on the screen of the test instrument using normal or angle probes in accordance with one of the three options given below:

• with the calibration block in accordance with No. 1 EN 12223 or No. 2 in accordance with EN 27963;

• with an alternative calibration blocks made in a material exhibiting similar acoustic properties to those of the material to be examined;

• on the casting itself when using normal probes. In this case, the casting to be tested shall have parallel sur­faces, the distance between which shall be measured.

Sensitivity setting shall be carried out after range setting (see 5.5.2) in accordance with EN 583-2. One of the fol­lowing two techniques shall be used:

— Distance-amplitude correction curve technique (DAC)

The distance-amplitude correction curve technique makes use of the echo-heights of a series of identical re­flectors (flat-bottomed holes FBH or side-drilled holes SDH), each reflector having a different sound-beam path.

NOTE A frequency of 2 MHz and a diameter of 6 mm for the flat-bottomed holes are most commonly used.

— Distance gain size technique (DGS)

The distance gain size technique makes use of a series of theoretically derived curves which link the sound­beam path, the apparatus gain and the diameter of a disc-shaped reflector which is perpendicular to the beam axis.

Transfer correction shall be determined according to EN 583-2.

When calibration blocks are used, transfer correction can be necessary. When determining the transfer correction, consideration shall be given not only to the quality of the coupling surface but also to that of the opposite surface because the opposite surface also influences the height of the backwall echo (used for calibration). If the opposite surface is machined or complies at least to the limit comparator 4 S1 or 4 S2 according to EN 1370, this surface has a quality which is sufficient for transfer correction measurements.