Interface layer deformation thickening analysis of hot rolling carbon steel–stainless steel clad plate

In this study, a stainless steel –carbon steel clad plate was rolled on a two-high mill. The microstructure and thickness of the bonding interface before and after the tensile test were observed through scanning electron microscopy. Results showed that the sample underwent plastic deformation via slipping in the static tension test, resulting in the rapid decrease in the Schmid factor (SF). However, the weighted average value of 1/SF increased from 2.1 to 2.2 after the tensile test. Consequently, the size of the grains with diameters between 12 and 120 μm decreased, whereas the percentage of grains with diameters of less than 5 μm sharply increased to 76.7%. The carbide layer in the bonding interface easily produced stress concentration and formed a fibrous region during the subsequent tensile test. The carbide particles in the bonding interface extended along the slip direction rather than the tensile direction, resulting in increased carbide thickness. The carbides hardly entered the SS but easily extended into the soft ferrite area of the CS surface. The deformation energy increased with a decreased in grain size, and the increase in the part size was the increment of the surface energy of the small grains.