Influencing Factors of Heat Transfer Coefficient in Air and Gas Quenching

摘要

Cooling rates during quenching play an important role in residual stress, distortion, and mechanical property distributions in the resultant metal components. Because the cooling rates of work pieces heavily depend on the interfacial heat transfer coefficient (HTC) between work pieces and quenchants, it is important to understand how HTC varies with respect to various influencing factors so that the HTC can be well controlled and the optimal quenching process can be achieved. In this paper, the influencing factors such as air/gas velocity, pressure, temperature, gas mixture and part orientation, air/gas temperature, air humidity, surface roughness, oxide and material to the variation of HTC are studied experimentally by using CHTE quenching system and theoretically by using empirical equations.