Best strain of austenitic stainless steel container welding residual stress overload reducing method

Abstract

The invention provides best strain of an austenitic stainless steel container welding residual stress overload reducing method. The best strain of the austenitic stainless steel container welding residual stress overload reducing method comprises: (1) a best value exists in overload dependent variable for reducing welding residual stress, the dependent variable corresponding to first major principal stress in direction in a continuous structure zone serves as an evaluation index and overload plastic strain is in a range of 2%-5%; (2) in the process of overload, boosting speed is controlled through a variable frequency pump or an automatic control reflux valve, uploading speed is in a range of 0.2 MPa / min-0.4 MPa / min and the dependent variable is controlled through deformation measurement or strain measurement; and (3) when a container is manufactured, a tensile test is firstly performed to materials, design stress and overload stress are determined according to an actual single tensile curve of the materials and design pressure and overload pressure are calculated through a simplified method. Numerical modeling has universality and generality, evaluation stress is corroded, first tensile welding residual stress is reduced to a great extent and the residual stress after reduction is in the same level with residual stress of a cold rolling plate rear base material and residual stress after stress relief heat treatment.

Description

technical field [0001] The invention belongs to a treatment method for reducing stress corrosion and fatigue damage of a welded pressure vessel, in particular to an optimal strain and control method for reducing welding residual stress by overload stretching of an austenitic stainless steel pressure vessel. Background technique [0002] At present, many equipment in industries such as weapons, aerospace, aircraft carrier shipbuilding, nuclear power, bridges, and pressure vessels are manufactured by welding methods. The internal restraint force formed after welding, that is, the residual stress, is generally higher than the working load stress, resulting in fatigue fracture during equipment use. , Stress corrosion cracking and deformation, so important equipment must reduce welding residual stress. [0003] Austenitic stainless steel is non-magnetic, has good corrosion resistance and ductility, and is widely used in many industries, especially nuclear power, food and medical ...

AI Technical Summary

Problems solved by technology

[0012] At present, there have been studies on the elimination of welding residual stress by overload method in China, but no research on the optimal strain

Images