Various inductors used for quenching rails and wheels with medium frequency induction heating equipment

Through the medium frequency induction heating equipment, the rail is heated to AC3+ (50-70) ℃, and then air-cooled to 750 ℃. Compressed air is sprayed to bring the rail cooling zone to about 500 ℃, and a sub-tempering heat treatment process is carried out. Its tissue is tempered. Sorbite. This process has stable production, no pollution to the environment, and flexible production methods. There are two types of intermediate frequency quenching inductors: pointed rail and continuous. The working principles of the two are the same. The intermediate frequency continuous quenching inductor includes the function of the pointed rail inductor, so its application range is wider.

a. The point rail medium frequency sensor is a continuous saddle-shaped sensor with a low temperature difference. It uses a 1000-2500HZ medium frequency current. Its characteristic is that the temperature between the rail angle and the tread is very small. By increasing the gap at the rounded corner, it is The ring effect and sharp corner effect are reduced, the gap is 10-12mm, and the distance between the tread and the tread is 2mm, so that the temperature difference between the two places is reduced to 20-30℃. Continuous spray or air jet cooling is used for quenching. Medium frequency quenching uses 100KW, 1000HZ precision gate silicon intermediate frequency power supply, the moving speed of the continuous quenching of the rail is 292-350mm/min, and the hardness and quenching layer depth at 9mm after quenching meet the requirements.

b. The medium-frequency continuous quenching sensor is used, which can not only quench the entire length of the rail, but also be suitable for quenching the point rail and rail end. The hardened layer of the device is hat-shaped. The moving speed of the rail's medium-frequency induction quenching should be based on the specific size and requirements. Waiting for confirmation, the cooling medium after medium frequency induction heating can be selected according to the material composition and technical requirements. There are spray, water spray and air first then water processes, etc. They have different cooling properties, so they should be used differently.

The heat treatment process of the rail: medium frequency preheating - medium frequency heating - cooling (when the surface temperature is below 750°C, compressed air cooling is carried out) - 500°C natural aging or tempering treatment, if air first and then cooling are used, then quenching It has fast speed, high production efficiency, stable process, small distortion or low cost, so it has been widely used.