Effect of interface oxides on shear properties of hot-rolled stainless steel clad plate

This paper aims at determine the effect of interface oxides on shear properties of 316L stainless steel/HSLA steel clad plate by studying interface microstructure, characteristics of interface oxides and shear fracture model. It was found that carbon element diffusion caused the forming of a decarburized ferrite zone (DFZ) of the substrate and a carburized austenite region (CAZ) of the clad metal, and between those two metals, a high-hardness band (HHB) with rapid element component change are formed in the solid-state diffusion bonding process. It was revealed that, at the micro-scale, when oxides concentrated area on the boundary of CAZ reaches up to a threshold size, DFZ crack may carve across the rigid HHB and propagate along CAZ boundary during the shear test. Thus macro-scale nonuniform distribution of oxides led to massive competitive cracking between the plastic DFZ and the high-strength CAZ, and statistically maintain the shear strength at a high level for test samples with a medium oxidation level. Nevertheless, those clad plates may still fail to meet the performance request of products, since the cladding interface tended toward a low fracture toughness failure during the process of deformation.