The process of camshaft induction quenching heat treatment by super audio frequency induction hardening machine

Cars, motorcycles, tractors, etc. all need to use camshafts. The camshafts are required to have sufficient hardness and wear resistance during the working process. In order to meet their working performance requirements, we usually use ultrasonic induction quenching machines to quench the cams. heat treatment. Zhengzhou Gou's has been engaged in the induction industry for fifteen years and has a good understanding of the heat treatment of workpieces. Today, we will talk about the induction heat treatment process of camshafts.

We usually use a 120kw super audio induction quenching machine for quenching heat treatment of camshafts on automobiles, while we use 60kw equipment for motorcycle camshafts for induction quenching heat treatment. The heat treatment process is as follows:

There are basically two types of induction hardening processes for cams. One is a segmented one-time heating method, and the other is a one-time heating method for the entire camshaft.

1. The camshaft adopts the induction quenching process of super audio frequency induction quenching machine:

1) Steel camshafts, cams and journals generally adopt a segmented one-time heating method. When the cam and journal have similar widths, they can share a sensor. The Jiefang brand automobile camshaft has four different parts: cam, journal, eccentric, and gear. They share one sensor and have good results. The difficulty of this process lies in the quenching and heating of the cam that is very close to the journal. When an 8-10kHz ultrasonic induction heating power supply is used, part of the electromagnetic field of the sensor will dissipate to the adjacent journal. In this way, part of the journal will return fire, and the heating temperature of the part of the cam on the journal side is low. Now the two ends of the cam sensor have been designed to be equipped with magnetic conductors, which solves this difficulty.

The second difficulty encountered in the camshaft process is that the distance between two adjacent cams is too close, such as 6-8mm apart. At this time, it is also difficult to attach a magnetic conductor to the inductor. The solution is to heat two adjacent cams together. However, due to the strong magnetic field in the middle of the inductor, the inductor must be designed so that the two effective circles in parallel are farther apart in the middle part and are not completely aligned with the cams. corresponding to the width.

2) For car alloy cast iron camshafts, a process in which multiple inductors are connected in series and the entire camshaft is heated at one time is generally used.

2. Quenching and cracking

Since the quenched surface hardness of the steel camshaft is required to be high, cracks are more likely to occur. Some manufacturers select the carbon content of camshaft steel to narrow the difference between the upper and lower limits.

3. Deformation of camshaft

For the camshaft heated in sections, there will be bending after quenching, but it is easy to correct because the rod part is not hardened. However, for camshafts where multiple cams are heated at one time, since the unhardened rod is shorter, a correction roller can be used if possible to reduce deformation.

4. Tempering

Cams that use segmented primary heating often use the self-tempering process. At this time, the quenching process should be set so that each time one part of the camshaft is heated and quenched, the next heated part should be located below the quenched part. This ensures that the quenched part does not need to be cooled a second time and has reliable self-tempering temperature and time. The cam often has insufficient self-tempering temperature, and the tip of the cam will be found to collapse before and after the next process. Sometimes many pieces of waste products with the same collapse form will be produced. Sometimes, waste products will also be produced due to the offset of the position of the sensor and the heating part.

Zhengzhou Gou's is a manufacturer that specializes in the production and sales of ultrasonic induction hardening machines and is quite familiar with the heat treatment of various workpieces. If you want to know more details about the camshaft quenching process, please call us for consultation.