BS EN 12681-2:2017:2018 Edition
$198.66
Founding. Radiographic testing – Techniques with digital detectors
| Published By | Publication Date | Number of Pages |
| BSI | 2018 | 68 |
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 describes 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 radiographs with equivalent sensitivity for detection of imperfections as film radiography, as specified in Part 1 of this standard. 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 AA and BA reflect the quality requirements of current automated and semi-automated radiographic inspection systems with DDAs (computer based flaw recognition or visual inspection) and mini or micro focus tubes (spot size ? 1 mm) with reduced requirements to the unsharpness. The described procedures are applicable to castings produced by any casting process, especially for steel, cast iron, 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; – real time testing with radioscopy.
PDF Catalog
| PDF Pages | PDF Title |
|---|---|
| 2 | undefined |
| 8 | 1 Scope 2 Normative references |
| 9 | 3 Terms and definitions |
| 15 | 4 Symbols and abbreviations |
| 16 | 5 Classification of radiographic techniques and compensation principles 5.1 Classification 5.2 Compensation principles |
| 17 | 6 General preparations and requirements 6.1 Protection against ionizing radiation 6.2 Surface preparation and stage of manufacture 6.3 Agreements |
| 18 | 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 |
| 19 | 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 |
| 23 | 8 Choice of tube voltage and radiation source 8.1 X-ray devices up to 1 000 kV |
| 25 | 8.2 Other radiation sources 9 Metal screens for IPs and shielding |
| 27 | 10 Reduction of scattered radiation 10.1 Metal filters and collimators |
| 28 | 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 |
| 30 | 11.3 Conditions for magnification ≥ 1,5 |
| 32 | 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 |
| 33 | 12.3 Bad pixel interpolation 12.4 Image processing |
| 34 | 13 Monitor viewing conditions and storage of digital images 14 Techniques for increasing the covered thickness range 14.1 General |
| 35 | 14.2 Contrast decreasing by higher radiation energy 14.3 Beam hardening 14.4 Thickness equalization |
| 36 | 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) |
| 37 | 16.2 Minimum image quality values 16.3 Minimum normalized signal-to-noise ratio (SNRN) |
| 38 | 16.4 Compensation principle CP II 16.5 Regular performance verification of digital radiography systems 17 Influence of crystalline structure |
| 39 | 18 Acceptances criteria 18.1 General 18.2 Severity levels 18.3 Wall section zones |
| 40 | 19 Test report |
| 42 | Annex A (normative)Minimum image quality values |
| 46 | Annex B (normative)Severity levels for steel castings |
| 49 | Annex C (normative)Severity levels for cast iron castings |
| 51 | Annex D (normative)Severity levels for aluminium and magnesium alloy castings |
| 54 | Annex E (normative)Severity levels for titanium and titanium alloy castings |
| 56 | Annex F (normative)Determination of basic spatial resolution |
| 60 | Annex G (normative)Determination of minimum grey values for CR practice G.1 Determination of SNRN from SNRmeasured |
| 61 | G.2 Determination of minimum grey values |
| 65 | Annex H (informative)Grey values, general remarks(from EN ISO 176362:2013, Annex E) H.1 Introduction H.2 Noise control |
