What is the induction hardening heat treatment of camshaft?

The heat treatment of camshafts is divided into surface quenching and chemical heat treatment. Most camshafts of internal combustion engines such as automobiles and tractors use induction heating to complete surface heat treatment to improve strength and wear resistance, ensuring that the camshaft has high fatigue strength during operation. and service life. The camshaft uses induction heating equipment for heat treatment, which has the characteristics of fast heating speed, stable quality, energy saving, mechanization and automation. Its heat treatment process has gradually matured and is easy to operate. Depending on the structure and requirements of the camshaft, induction heating surface quenching can be performed on different parts of the camshaft, such as the cam, bearing journal, eccentric wheel, and gear, according to different requirements.

Heating method: Depending on the camshaft structure, one part can be heated at a time (camshafts for medium-sized or larger multi-cylinder engines) or multiple parts can be heated at one time (camshafts for light and small engines)

For camshaft quenching, the induction coil should be selected first, and then the quenching temperature should be selected. The sensor should be made and designed according to the requirements. The height of the sensor should be 4-8mm higher than the camshaft, and the gap between the inner diameter and the shaft diameter should be between 3-4mm. Camshaft (especially cam) quenching sensors can generally be divided into two categories: circular sensors and imitation cam-shaped sensors. The former is widely used, and is mostly used for medium-frequency induction heating surface quenching of camshafts. The latter is mostly used for high-frequency induction heating surface quenching of cams or cams with special shapes and special requirements. The inner diameter of the circular inductor is larger than the outer diameter of the supporting journal, the gap between the parts and the inductor is large, and the gap between the cam periphery and the inductor is not equal, so the parts are rotated and heated. The quenching of multiple cams (or multiple parts) at the same time uses a combined inductor with multiple circular inductors connected in parallel, and the heating method uses rotating heating of the parts. For the imitation cam shape sensor, the gap between the part and the sensor is small and relatively uniform. The gap can change the imitation shape according to the requirements of different hardened layers in each part of the cam. In order to obtain a uniform hardened layer depth around the cam, the gap is generally increased for the part with a smaller curvature radius. Imitation cam-shaped sensors are generally made into separate types and are suitable for single-piece and small batch production.

When the camshaft is quenched, the frequency should be selected according to the induction heating melody. Different frequencies will have different depths of the quenching layer. The higher the frequency, the shallower the depth of the quenching layer. Therefore, a reasonable value should be determined based on the technical requirements of the workpiece. process parameters. According to the depth and performance of the hardened layer of the camshaft, it is more appropriate to use medium frequency induction hardening. The medium frequency induction quenching of the camshaft should be carried out in a distributed manner. The supporting shaft diameter and gear surface are quenched first, and finally the cam and eccentric are surface quenched. The purpose of this is to ensure that the structure and hardness are not affected after heat treatment. After completing surface quenching, the camshaft should be immediately placed in a medium frequency induction heating tempering furnace for tempering treatment. After medium frequency quenching, the waste heat can also be used for self-tempering to eliminate the use of quenched structures. The temperature of self-tempering is 50-70°C higher than the tempering in the furnace.

In the induction hardening of the camshaft, it often occurs that the distance between the cams or between the cams and other quenched parts (such as eccentrics, gears, etc.) is too small, and the post-quenched cam has a negative impact on the adjacent quenched cam or other quenched parts. The quenching part causes tempering, which reduces the hardness there. This is caused by the magnetic field leakage at both ends of the axial direction of the inductor causing the quenched cam to be reheated locally. In order to avoid this phenomenon, shielding measures must be taken at both axial ends of the sensor.

As mentioned above, medium frequency induction quenching is more suitable for quenching the camshaft. Zhengzhou Gou's is a professional manufacturer of this kind of medium frequency induction quenching equipment. The company has been engaged in the production, manufacturing and sales of induction heating equipment for many years. The medium frequency induction annealing equipment produced has the advantages of complete functions, convenient and simple operation, energy saving and environmental protection, and is ideal for camshafts. The best equipment for quenching.