Study On The Mechanical Behavior Of Austenitic Stainless Steel Welding Joint After Codestretching

The light-weight of cryogenic pressure vessels from austenitic stainless steels can be carried out by using coldstretching technology, which may reduce the production costs. The yield strength of austenitic stainless steels can be significantly increased by coldstretching, thusing thinning the wall thickness of pressure vessels.The small punch technology was used to study the mechanical properties of coldstretched welding joints in this paper. Because the small punch specimen is very small, sampling from different parts of welding joint such as the weld or the base material can be got, which are used to study the mechanical properties of welding joint respectively.The reasonable evaluation of welding joint can be got, meanwhile, the strength match situation of the welding joint can be evaluated, which is benefit to selecting proper welding material.The main content and conclusions of the study are summarized as follows:1. The small punch test is innovatively used to study the mechanical properties of welded joints. The result shows that weld got good impact toughness, bending and elongation properties in the paper, while the welding material have high yield strength and low tensile strength;2. Finite element analysis method was used to analyze the specimen stretched by the stress control method and strain control method. It is found that when using the strain control method, the strain of the welding seam become smaller with a longer gauge. Compared with the stress control method, the strain of the welding seam is much higher than that with the 9% strain control method;3. Finite element analysis method is used to study the effect of stain strengthening on the deformation of welding seam with different yield strength matching factor M. It shows that the larger the factor M, the smaller the stain of welding seam. And to a certain extent, weld reinforcement can reduce the amount of deformation of the welding seam.