The diffusion behavior of Cr and Ni in the bonding interface of 60 nun Q345B carbon steel/10 mm 304 stainless steel clad plate being heated at 1 200 °C without rolling and being rolled to 30 mm Q345/5 mm 304 clad plate with 2 times compression ratio has been studied. The test results show that whether the interface contact or non-contact does not affect the diffusion during the heating process. Under the vacuum condition

Cr and Ni evaporate from the stainless steel side and diffuse to the carbon steel side

and tlie diffusion distance of Cr is greater than that of Ni. During the rolling process

the metallurgical bonding is established at the composite interface. The difference in the concentration of Cr and Ni on both sides of the interface drove the diffusion of Cr and Ni to the carbon steel side

and the initial heating diffusion zone is rolled and thinned. The concentration difference of Cr on both sides of the bonding interface is small while that of Ni is large. After 2 times compression ratio hot rolling

only 20μm width Cr and 10μm width Ni depletion zones are formed on the stainless steel side.