Envision Product Design King Street Anchorage, Alaska Code Requirements For Weld Inspections with CMOS Digital X-ray ASNT Fall Conference 2003 John A. Pursley & John P. Cope

Qualifying Weld Inspections with Digital X-ray Radioscopic Examination Interpretation, Evaluation, & Disposition Personnel Certification

System Acceptance ASTM Section V Article 22 SE Summary of Practice: “Manual evaluation as well as computer-aided automated radioscopic examinations are used in a wide variety of penetrating radiation examination applications…Systems having a wide range of capabilities between these extremes can be assembled using available components. Guide E1000 lists many different system configurations.”

Radioscopic Examination ASME Section V Article 2 Mandatory Appendix II II-210 Scope: “Real-time radioscopy may be performed on materials including castings and weldments when modified provisions to Article 2 as indicated herein are satisfied. (ASTM) SE-1255 shall be used in conjunction with this appendix as indicated by specific references in appropriate paragraphs. SE-1416 provides additional information that may be used for radioscopic examination of welds.”

Radioscopic Examination ASME Section V Article 2 Mandatory Appendix II II-220 General Requirements: “This radioscopic methodology may be used for the examination of ferrous or nonferrous materials and weldments” ASTM Section V Article 22 SE Significance and Use: “As with conventional radiography, radioscopic examination is broadly applicable to any material or test object through which a beam of penetrating radiation may be passed and detected including metals, plastics, ceramics, composite, and other non- metalic materials”

Radioscopic Examination ASTM SE Detection System: “The detector may be of one-dimensional design, providing test part information one line at a time, or may be a two-dimensional area detector providing an area field of view.”

Radioscopic Examination ASME Section V Article 2 Mandatory Appendix II II-230 Equipment and Materials: II-235 Calibration Block “…may be an actual test object or may be fabricated to simulate the test object with known discontinuities” II-236 Calibrated Line Pair Test Pattern and Step Wedge “The line pair test pattern shall be used without an additional absorber to evaluate system resolution. The step wedge shall be used to evaluate system contrast sensitivity.”

Radioscopic Examination ASME Section V Article 2 Mandatory Appendix II II-237 Equivalent Performance Level “A system which exhibits a spatial resolution of 3 lp/mm, a thin section contrast sensitivity of 3%, and a thick section contrast sensitivity of 2% has an equivalent performance level of 3% - 2% - 3 lp/mm.” This requirement is the digital equivalent of radiographic density using film.

Radioscopic Examination ASME Section V Article 2 Mandatory Appendix II II-260 Calibration: “System calibration shall be performed in the static mode by satisfying the line pair test pattern resolution, step wedge contrast sensitivity, and calibration block discontinuity detection necessary to meet the IQI requirements of T-276.”

Radioscopic Examination ASME Section V Article 2 Mandatory Appendix II II-263 System Performance Measurement “…system performance parameters shall be determined initially and monitored regularly with the system in operation to assure consistent results. System performance tests require the use of the calibration block, line pair test pattern, and the step wedge.”

Procedure Requirements ASME Section V Article 2 Mandatory Appendix II II-221 Procedure Requirements: “A written procedure is required and shall contain as a minimum the following (see SE-1255 Section 5.2 ):” a) material and thickness range b) equipment qualifications c) test object scan plan d) radioscopic parameters e) image processing parameters f) image display parameters g) image archiving

Interpretation, Evaluation, & Disposition ASME Section V Article 2 Mandatory Appendix IV IV-220 General Requirements: “The digital image shall be interpreted while displayed on a CRT (soft display). The interpretation may include density and contrast adjustments, quantification, and pixel measurement, including digital or optical density values and linear or area measurements. The interpretation of a digitized image is dependent on the same subjective evaluation by a trained interpreter as the interpretation of a radiographic or radioscopic image.”

Interpretation, Evaluation, & Disposition ASME Section V Article 2 Mandatory Appendix IV IV-221 Procedure Requirements: “A written procedure is required and shall contain, as a minimum, the following system performance parameters:” a) image digitizing parameters - MTF, line pair resolution, contrast sensitivity, dynamic range, and pixel size; b) image display parameters – monitor size including display pixel size, luminosity, format, contrast, and magnification; c) signal processing parameters – including density shift, contrast shift, log transform, and any other techniques that do not mathmatically alter the original data…; d) storage – identification, data, compression, and media. The non-erasable optical media should be used for archival applications. CD-R or DVD-R

Radioscopic Examination ASME Section V Article 2 Mandatory Appendix II II-231 Radioscopic Examination Record: “The radioscopic examination shall be recorded and stored on videotape, magnetic disk, or optical disk.”

Interpretation, Evaluation, & Disposition ASME Section V Article 2 Mandatory Appendix IV IV-234 Viewing Considerations: “The digital image shall be evaluated using the appropriate monitor luminosity, display techniques, and room lighting to assure proper visualization of detail.” ASTM Article 22 SE Importance of Proper Environmental Conditions: “Proper reduced lighting intensity is extremely important to provide for high-contrast glare-free viewing of radioscopic examination images.”

Personnel Certification ASME Section V Article 2 Mandatory Appendix VI VI-223 Personnel Requirements: “a) Level II and Level III personnel shall be qualified in the radiographic method as required by Article 1. In addition, the employer’s written practice shall describe the specific training and practical experience of Level II and Level III personnel involved in the application of the digital imaging process and the interpretation of results and acceptance of system performance. Training and experience shall be documented in the individual’s certification record. b) As a minimum, Level II and Level III individuals shall have 40 hours of training and one month of practical experience in the digital imaging process technique.”

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Disclaimer The authors of this brief paper have used their best efforts to identify and accurately quote a sampling of relevant provisions of ASME and ASTM code requirements relating to the use of CMOS digital X-ray systems for weld inspection. However, it remains the responsibility of all organizations involved to seek out and apply all appropriate code requirements, which may or may not be presented here.

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