This standard specifies the radiography process and quality grading of butt fusion welded-joint of pressure steel pipes and tubes (hereafter referred to as butt joint).
This standard is applicable to radiographic examination of component with radiography thickness of 2~175mm during the manufacturing, installation and overhaul of power equipment by power industry, including the butt joint with single-side welding and double-side forming of pressure pipes, tubes and container. The radiographic examination of welded pipes (welded pipe with longitudinal joint and helical welded pipe) and pipe fittings (tee and elbow) may also refer to it.
This standard is not applicable to the butt joint welded with mechanical method such as friction welding, flash welding etc.
2 Normative References
The following normative documents contain provisions which, through reference in this text, constitute provisions of this standard. For dated references, subsequent amendments (excluding corrections), or revisions, of any of these publications do not apply to this standard. However parties to agreements based on this standard are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies.
GB 4792 Basic Health Standards for Radiological Protection
DL/T 675 Examination Code for Qualification of Non-destructive Testing Personnel of Electric Power Industry
DL 5007 Code for Design of Erection and Acceptance for Power Plant Construction (Welding Section)
JB/T 7902 Wire Type Image Quality Indicator
3 Radiographic Testing Personnel
3.1 Basic conditions for radiographic testing personnel
3.1.1 Radiographic testing personnel shall have favorable physical quality, in addition, their vision must meet the following requirements:
a) The corrected vision shall not be less than 1.0 and be inspected once per year;
b) The radiographic film evaluating personnel shall be able to distinguish a group of printed letters with height of 0.5mm and spacing of 0.5mm from a distance of 400mm.
3.1.2 Radiographic testing personnel must obtain technical training and obtain the corresponding qualification certificate through the assessment according to those specified in DL/T 675.
3.1.3 Radiographic testing personnel must comply with the requirements of GB 4792; they must pass through the technical training organized by the National Health Protection Department and obtain the radiation staff card issued by National Health Administrative Department.
3.2 Technical grade of radiographic testing personnel
3.2.1 The technical grades of radiographic testing personnel are classified into Grade III (high), Grade II (medium) and Grade I (primary).
