Influence of Deformation Rate on Overload Performance and Microstructure of Spot Welded Metastable Austenitic Stainless Steel

摘要

Tensile-shear overload tests of spot welded cold-rolled 301LN plates deforming with slow and fast rates were carried out. The deformation behaviors of spot welds can be divided into two stages. Loading force with fast deformation rate increased more along with displacement in the first stage, while the force with slow rate increased more in the second stage. 21and 32(v.%) α'-martensite were introduced by failure deformation with fast and slow rates respectively. The hardness under the fracture surfaces was higher than HV400, which was more than two times of their original. The ultimate strengths and fracture energy absorptions of spot welds deforming with slow rate were higher than that with fast rate, especially for spot-welded thicker plates. Keywords: cold-rolled 301LN plate, spot weld, deformation rate, overloads performance.