Effect of different reduction rates on the near-interfacial structure of pressed 304/Q235 composite plate

The 304 stainless steel/Q235 composite plate was pressed at 1200 °C using a 500-ton hydraulic testing machine at a reduction rate of 25%, 30%, 35%, and 40% respectively. The microstructure of the composite plate was analyzed by means of scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). The results showed that the black matter at the interface was the oxide of Mn and Si, and during the compression deformation process, the partial oxide film and the linear inclusions were crushed and extruded into fine particles. Small grains of different sizes appeared on the composite interface, and this deformation made the Q235 carbon steel and the 304 stainless steel on both sides of the composite interface show a coordinated deformation tendency when the reduction rate reached 35%. The whole process showed that the deformed carbon steel was first deformed, and the hard-to-deform stainless steel began to be deformed at a certain point, and then they were both further deformed together.