Influence of Pouring Temperature on Interfacial Bonding of 40Cr/Q345B Bimetallic Ring Blank Produced by Centrifugal Casting

In this paper, the horizontal centrifugal casting process of 40Cr/Q345B bimetallic ring blank was simulated by FLOW-3D. The effects of pouring temperature and axial temperature difference on the quality and consistency of interfacial bonding were studied. The bonding quality and overall performance of the bimetallic ring blanks were investigated by diffusion behavior, microstructure and mechanical properties. The results showed that when the initial outer temperature or the inner pouring temperature was too high, mix flow easily occurred at the interface; when the initial outer temperature or the inner pouring temperature was too low, the interface was poorly bonded. The consistency of interfacial bonding was affected by the axial temperature difference. When the initial outer temperature was 1350 °C, and the inner pouring temperature was 1580 °C, the interface was well bonded. Gradient transitions were formed in the elemental distribution and microstructure of the bonding layer. No obvious defects were found in the bonding area. The mechanical properties of the bimetal were close to those of Q345B, which were between those of 40Cr and Q345B. According to the simulation results and experimental results, it was concluded that the bonding mechanism of the 40Cr/Q345B bimetallic interface was first fusion and then diffusion.