5 million datum including data of 28100 groups of steel plates and 20400 groups of steel tubes,and obtained much important information about condition of being used and technical level of pressure equipment materials.

The optimum production process has been established,which offers condition terms for developing higher grade steel plate for pressure equipment.

Fundamental research of pressure equipment and its priority research areas.;

It elucidated the welding material technical requirement of pressure equipments in China and the harm of two systems about current welding .

This paper probes into some problems existing in the application of safety valve of pressure equipment,and advances some solving measures.

Welding materials are one of the major materials of bearing pressure equipment.

The specifications have not been able to meet the requirement for welding of bearing pressure equipment.

The main content included the analysis of the present situation of steel welding material standard,proved has not been able to satisfy the bearing pressure equipment the request.

In this paper,5% primacy principal strain criterion indicates that gross plastic deformation occurs when a pressure vessel(of ductile material) has a value of 5% maximum principal strain at any point.