Effects Of Cold Work On The Material Surface Hardness And Plastic Material Parameters

Structural integrity analysis is one of the significant guarantee for the safe service of important mechanical structures,and the accurate material mechanical parameters are the important basic data for the integrity evaluation of practical engineering structures.Since cold working will change the mechanical parameters of the local region material,these local regions arc often the key parts of structural integrity analysis.To obtain the accurate mechanical properties of these local regions,the relationship between cold work and surface hardness and the relationship between hardness and yield stress were established using hcorctical,numerical simulation and experimental methods.The main work as follows:(1)The nuclear welded joint material 316L austenitic stainless steel was taken as research object,the relationship between 316L austenitic stainless steel vickers hardness and yield stress was acquired by the vickers hardness test and the ABAQUS finite element simulation analysis.(2)The influence of stress,plastic strain and indentation depth of indentation zone was studied by nonlinear finite element method under indenter load,offset coefficient,strain hardening index and yield stress.(3)The tensile test of 316L austenitic stainless steel was carried out using fatigue tensile testing machine.Vickers hardness test was carried out after cold wording and the experiment was simulated numerically at the same time.The effect of cold working amount on the yield stress of the material is obtained.(4)Based on the hardness test and finite element simulation of the 316L austenitic stainless steel,the cold working phenomenon caused by welded residual stress and its effect on the mechanical properties of the material are analyzed.