What are the disadvantages of spring collets after quenching by high frequency induction heating equipment? How to improve?

Due to the complex shape of the head of the spring collet, problems such as cracking, decarburization, deformation, overheating, and insufficient hardness are prone to occur after quenching with high-frequency heating equipment.

1. Cracking: During the overall heating process of the spring collet, the austenite grains inside the collet become thicker and larger due to too high temperature or too long heating time, and the austenite grains transform into coarse ones after quenching. Martensite, which in turn increases the brittleness of the collet, makes the thickness of the neck very thin, reduces its strength and toughness, and causes the neck to crack. Or when heating in an environment with protective gas, due to the reducing medium in the environment, the surface of the neck will be carburized. After quenching and cooling, the hardness of the neck of the collet will become very high. High, the brittleness increases, and vice versa, the elasticity decreases, which will also cause neck cracking. Another situation is that the hardness of the collet neck exceeds the hardness required by the high-frequency heating equipment for heat treatment, which leads to insufficient elasticity of the neck, increased brittleness, and more prone to fracture during clamping.

So in order to reduce the deformation and cracking of the collet, we must strictly implement the standard heat treatment process specification, first heat the head of the collet, and then heat the whole. When heating, in order to avoid abrasion of the neck, it can be protected with asbestos in advance. After quenching, heating and heat preservation, the thinner part of the neck can be quenched again.

2. Decarburization: When the collet is quenched and heated, the surface is prone to oxidative decarburization, which will cause soft spots or ferrite inside, which not only reduces the hardness of the collet surface, but also reduces its In the process of use, fatigue fracture is easy to occur. For this, we can increase the heating rate, perform rapid heating, or perform heat treatment in a protective environment.

3. Overheating: If the heating or holding time is too long, the brittleness of the collet will increase. For this problem, we must strictly control the quenching and heating temperature of the chuck, and operate according to the required process parameters.

4. Insufficient hardness: If the hardness of the collet is not up to the standard, it will be deformed and its service life will be reduced. In this regard, we must choose raw materials with better performance, increase the quenching heating temperature of the chuck, and improve the cooling medium.