Technical Advances of Chinese Standards for NDT of Pressure Equipment

JB4730-94 “pressure vessel NDT” is a compulsory Chinese industrial NDT standard for manufacture and erection of pressure vessel and pressure pipeline. Since more than 10 years from implementation of this standard, it has played a positive role in normalization of pressure vessel management, improvement of design, material selection, manufacture, use and inspection level of pressure vessel sector, reduction of explosion accidents, etc. In the year 2000, Chinese government decided to entrust us to revise JB4730, the revised JB4730-2005 “Pressure vessel NDT” is a backbone standard of Chinese pressure equipment sector. It defines the five major conventional inspection methods such as RT, UT, MT, PT and eddy-current inspection and qualification of quality class (it also defines the use of new NDT technology such as AE, real-time radiographic imaging, etc. in some special applications.) Because the number and use scope of Chinese domestic in-service pressure equipment have already reached a rather substantial scale and there is a lack of inspection standards, we added the content concerning the NDT of in-service pressure equipment. In order to meet the needs for macro-scale operations technology of equipment and wide application of corrosion resistant materials, we absorbed the research achievements on NDT of recent years, extended the application range of the standard, for example, we expanded the thickness range for RT of buttwelds to 2∼400mm; expanded the thickness range of UT to 6∼400mm; newly added the contents for NDT of the pressure equipment made of austenitic stainless steel, duplex stainless steel, nickel and nickel alloy, copper and copper alloy, aluminum and aluminum alloy and titanium and titanium alloy; added the content for UT of circumferential buttwelds on small-diameter thin-wall steel pipes. In this paper a systematic description is given to the main revision content and revision background of JB4730 standard, which has some directive significance for understanding and learning the present situation and development tendency of NDT of Chinese pressure equipment.