National foreword

This British Standard is the UK implementation of EN 12681‑2:2017.

The UK participation in its preparation was entrusted to Technical Committee ISE/111, Steel Castings and Forgings.

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

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 cannot confer immunity from legal obligations.

This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2017.

This European Standard was approved by CEN on 16 July 2017.

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, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.

European foreword

This document (EN 12681‑2:2017) 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of an identical text or by endorsement, at the latest by May 2018, and conflicting national standards shall be withdrawn at the latest by May 2018.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN shall not be held responsible for identifying any or all such patent rights.

Within its programme of work, Technical Committee CEN/TC 190 requested CEN/TC 190/WG 10 “Testing for inner discontinuities”:

to revise EN 12681:2003 into EN 12681‑1, Founding — Radiographic testing — Part 1: Film techniques;
and the preparation of a further standard EN 12681‑2, Founding — Radiographic testing — Part 2: Techniques with digital detectors.

According to the CEN-CENELEC Internal Regulations, the national standards organisations 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, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom.

Introduction

Radiography can be used to detect internal discontinuities in a casting. The discontinuities can be gas holes, non-metallic inclusions, shrinkage, cracks, inserts or chills or inclusions that have lower or higher densities than the parent metal. This European Standard gives acceptance criteria through severity levels.

1 Scope

This European Standard gives specific procedures for industrial X-ray and gamma radiography for discontinuity detection purposes, using NDT (non-destructive testing) digital X-ray image detectors. This part of EN 12681 specifies the requirements for digital radiographic testing by either computed radiography (CR) or radiography with digital detector arrays (DDA) of castings.

Digital detectors provide a digital grey value image which can be viewed and evaluated using a computer.

NOTE This part of EN 12681 complies with EN 14784‑2 for CR. Some clauses and annexes are taken from EN ISO 17636‑2.

This part of EN 12681 specifies the recommended procedure for detector selection and radiographic practice. Selection of computer, software, monitor, printer and viewing conditions are important but are not the main focus of this standard. The procedure specified in this standard provides the minimum requirements for radiographic practice which permit exposure and acquisition of digital images with equivalent sensitivity for detection of imperfections as film radiography, as specified in Part 1 of this standard.

This standard does not consider radiographic or radioscopic fitness for purpose testing as applied for specific castings based on manufacturer’s internal requirements and procedures.

The requirements on image quality in class A and B testing of Annex A consider the good workmanship quality for general casting applications as also required in Part 1 of this standard for film radiography.

The classes A_A and B_A reflect the quality requirements of current automated and semi-automated radiographic testing systems with DDAs and computer or operator based image evaluation, and mini or micro focus tubes (spot size ≤ 1 mm) with reduced requirements to the unsharpness, but unchanged requirements to contrast sensitivity as also required in Part 1 of this standard for film radiography.

The specified procedures are applicable to castings produced by any casting process, especially for steels, cast irons, aluminium, cobalt, copper, magnesium, nickel, titanium, zinc and any alloys of them.

This part of this European Standard does not apply to:

the testing of welded joints (see EN ISO 17636‑2);
film radiography (see EN 12681‑1:2017);
real time testing with radioscopy (see EN 13068‑1; radioscopy with image intensifiers).

2 Normative references

3 Terms and definitions

4 Symbols and abbreviations

5 Classification of radiographic techniques and compensation principles

5.1 Classification

5.2 Compensation principles

6 General preparations and requirements

6.1 Protection against ionizing radiation

6.2 Surface preparation and stage of manufacture

6.3 Agreements

6.4 Personnel qualification

7 Test arrangements

7.1 General

7.2 Single wall radiography of plane areas

7.3 Single wall radiography of curved areas

7.4 Double wall radiography of plane and curved areas

7.5 Choice of test arrangements for complex geometries

7.6 Acceptable test area dimensions

8 Choice of tube voltage and radiation source

8.1 X-ray devices up to 1 000 kV

8.2 Other radiation sources

9 Metal screens for IPs and shielding

10 Reduction of scattered radiation

10.1 Metal filters and collimators

10.2 Interception of backscattered radiation

11 Source object and detector position

11.1 General

11.2 Source-to-object distance for magnification < 1,5

11.3 Conditions for magnification ≥ 1,5

11.4 Identification of image, test area, detector position plan

12 Data processing

12.1 Scan and read out of image

12.2 Calibration of DDAs

12.3 Bad pixel interpolation

12.4 Image processing

13 Monitor viewing conditions and storage of digital images

14 Techniques for increasing the covered thickness range

14.1 General

14.2 Contrast decreasing by higher radiation energy

14.3 Beam hardening

14.4 Thickness equalization

15 Requirements on images

15.1 Identification of images

15.2 Marking of the test areas

15.3 Overlap of digital images

16 Image quality

16.1 Types and positions of image quality indicators (IQI)

16.2 Minimum image quality values

16.3 Minimum normalized signal-to-noise ratio (SNR_N)

16.4 Compensation principle CP II

16.5 Regular performance verification of digital radiography systems

17 Influence of crystalline structure

18 Acceptances criteria

18.1 General

18.2 Severity levels

18.3 Wall section zones

19 Test report

Bibliography

BS EN 12681-2:2017

Founding. Radiographic testing - Techniques with digital detectors

Current, Under Review

Published:

31 Jan 2018