In Situ studies of the dynamics of strain fields in welded joints of austenitic stainless steel under tensile loads

Abstract

In this paper, the dynamics of strain fields in both austenitic stainless steel plate and its butt-welded joint under tensile loads was studied in situ by the digital image correlation methods. Stages of their stress–strain curves were determined, which correlated with the change in the distribution of the stain fields on the surface of samples. Based on their analysis, it was found that the presence of the weld in the sample center perpendicular to the applied uniaxial tensile load prevented the formation of the sample thinning. It was shown that the γ→ε→α strain-induced phase transformations, that occurred in the heat-affected zone and in the weld metal contributed to the existence of the yield point on the stress-strain curve, as well as the accumulation and dissipation of mechanical energy due to the rearrangement of the crystal lattice.