The double guide rails of the lathe use high-frequency induction quenching equipment for surface quenching

①Lathe double guide rail section and sensor. The guide rail material is HT300.

②High frequency quenching heat treatment process specifications

a. High frequency quenching process

b. High frequency quenching heating temperature range. Generally controlled at 900-950℃, the quenching medium is generally spray-cooled with tap water with a pressure of 0.1~0-15MPa.

③Analysis of high-frequency induction heating surface quenching process

a.Double-rail high-frequency quenching inductor. It can be regarded as a combination of two monorail high-frequency quenching inductors. Its design principle is consistent with that of the monorail high-frequency quenching inductor. It is a mountain-shaped guide rail high-frequency quenching inductor.

b. Selection of quenching heating temperature. In the high-frequency quenching process operation, the selection of quenching heating temperature is more critical. The quenching heating temperature is too high, the phosphorus eutectic melts, the austenitized structure becomes coarse, the amount of residual austenite increases after quenching, and the wear resistance decreases; the quenching heating temperature is too low, the austenitization is incomplete, and the carbides have no time to dissolve In austenite, the surface hardness is low after quenching and the wear resistance is also poor.

c. The hardness of the guide rail after quenching should be ≥45HRC

d. Microstructure of the hardened layer: Cryptocrystalline martensitic graphite, the depth of the hardened layer is about 1.5mm.

a.Selection of moving speed. Under certain other process parameters, the slower the moving speed, the deeper the hardened layer, but the production efficiency will be reduced. If the moving speed is too slow, the surface hardness will be reduced, so the moving speed should be controlled within the range of 1.2 to 3mm/s.

b. The choice of quenching heating temperature is key. The most suitable quenching heating temperature should be above the austenitizing temperature and below the melting point of phosphorus eutectic 957°C. Generally, the temperature range is 900~950°C.

c.Quenching medium. Due to the presence of a large amount of graphite in cast iron, the heat conduction rate is reduced, and the role of Si and Mn elements also reduces the critical cooling rate. Therefore, high-frequency induction heating surface quenching of cast iron guide rails does not have high requirements on the cooling capacity of the quenching medium. Generally, tap water spray cooling is used, and the water pressure is 1 0. 1 ~ 0. 15MPa.