Microhardness investigation of 0Cr18Ni10Ti stainless steel welded joint

Vickers microhardness tester equipped with diamond pyramid indenter was used to measure the microhardness of the 0Cr18Ni10Ti stainless steel welded joint. Indentation size effects (ISE) of different regions, including the weld metal (WM), base metal (BM), fusion zone (FZ) and heat-affected zone (HAZ), were studied at loads varying from 0.098 to 4.9 N for a constant holding time of 10 s. The results show that the microhardness for each region of the welded joint decreases with increasing load at comparatively low loads, and then tends to invariable as the indentation load exceeds 1.96 N. The PSR model was adopted to accurately describe the variation of the hardness as a function of indentation load. The error between the tested hardness at 1.96 N load and the calculated value using this model is less than 3%. Indentation tests were also successively performed across the welded joint using 2.94 N load to evaluate the distributions of the microhardness in different regions of the welded joint and the optical microstructures were observed and analyzed.