射线检查程序RADIOGRAPHIC EXAMINATION PROCEDURE.docVIP

RADIOGRAPHIC EXAMINATION PROCEDURE FOR BUTT WELDS Revision 0 Date 30/04/2017 Page PAGE 1 of NUMPAGES 19 RADIOGRAPHIC EXAMINATION PROCEDURE 3 2 1 0 REVISION PREPARED BY REVIEWED BY APPROVED BY AI General This procedure is applied to the x-ray radiographic examination of welds for pressure vessels in accordance with ASME Code Section I、 Section V and Section Ⅷ Division 12. 1.2 This procedure is used to defect discontinuities in ferrous welds and waterial with a thickness range between 4 mm and 50.8mm. 2. Qualification of Examination Personnel 2.1 Any person engaged in the radiographic examination shall be qualified and certified as a radiographic examiner in accordance with “Written Practice for NDE Personnel Training, Examination，Qualification and Certification ” 2.2 Radiographers shall be at least level Ⅰ, Radiographic interpreters shall be at least level Ⅱ. 3. Equipment, Tools and Materials 3.1 x-ray equipment shall be selected from Table 1. Table 1 Type Manufactory Max. Tube Voltage (kVp) Max. Tube Current (mA) Focus. Size (mm) Permitted max. material thickness (mm) (steel) 300EG-S3 RIGAKV CORPORATION 300 5 2.5×2.5 50 250EG-S3 RIGAKV CORPORATION 250 5 2.0×2.0 30 3.2 Film 3.2.1 Film selection shall be in accordance with ASTM E-1815, Standard Test Method for Film Systems for Industrial Radiography. The classification table of film shall be provided by the film manufacturer. Film system classes Special, Ⅰ,Ⅱ,Ⅲ,W-A, and W-B are permitted. Depending on the x-ray penetration thickness, a suitable film shall be selected .When using two films method; two different types of film shall be selected. 3.2.2 Film KODAK AA 400 may be used 3.3 Intensifying Screens A suitable lead screen shall be selected from Table 2. Table 2 Tube Voltage Thickness of lead Screen (mm) Front Back ＜150 kVp 0.03 0.03 150～300 kVp 0.03 0.10 3.4 Densitometer and Step Wedge Calibration Film 3.4.1 The transmission densitometer listed in Table 3 shall be used for judging ra