In the traditional electric furnace temperature control system, most of the main circuits use AC contactors to control the power supply of the electric furnace, GCr15 Bearing Steel Effect Of Tempering Temperature On Microstructure And Propertiesand the furnace temperature is controlled by a combination of temperature instrument monitoring and manual adjustment. Although this control method has a simple structure, it has poor control accuracy, slow control speed, labor-intensive, high energy consumption, and high noise. Moreover, the contactor is frequently switched on and off during the temperature control process, and contact arc discharge often occurs. Short circuit,Shaft machining vacuum heat treatment damage the contactor, and adversely affect the safety of operators and equipment. Vacuum carburizing process of auto partsTherefore, the application of microcomputer technology to heat treatment process control is an inevitable trend to improve the quality of heat treatment products and reduce production costs.