Experimental investigation on the heterogeneous ratchetting of SUS301L stainless steel butt weld joint during uniaxial cyclic loading

By using a non-contact digital image correlation (DIC) technology, the ratchetting of SUS301L stainless steel butt weld joint is investigated under an asymmetric uniaxial stress-controlled cyclic loading condition. The effects of nominal stress amplitude, mean stress and stress rate on the heterogeneous ratchetting of the weld joint are discussed in different zones, i.e., fusion zones (FZs), heat affected zones (HAZs). The experimental results show that the ratchetting and its evolution rate of the weld joint are heterogeneous in different zones and are obviously different from each other. The most remarkable ratchetting occurs in the fusion zone (FZ) of the weld joint since the discussed butt weld joint of SUS301L stainless steel here has been proved to be a kind of weak weld connection by the measurement of micro-hardness. The heterogeneous ratchetting of the weld joint is also more remarkable in the load cases with higher nominal stress amplitude and mean stress but at lower stress rate, which is similar to that of homogeneous austenitic stainless steels.