Vacuum heat treatment is a comprehensive technology combining vacuum technology with heat treatment, which refers to all and part of the heat treatmentprocess in vacuum, Vacuum heat treatment furace has high thermal eficiency,can achieve rapid heating and cooing,can achieve no oxidation, no decarbonization,no carburization,can remove the surface of the workpiece phosphorus chip, and degreasing and degassing, so as to achieve a bright surface purification efect.