Chromium bearing steel is normalized and heat treated using a high-frequency induction annealing machine. What defects are likely to occur?

Chromium bearing steel is normalized and heat treated using a high-frequency induction annealing machine. Affected by operating techniques, raw materials and other factors, defects such as decarburization and cracks may occur. These defects may at least affect the service life of chromium bearing steel, or at worst may cause chromium bearing steel to be scrapped. Therefore, it is very important to understand the causes of defects and how to prevent them.

Chromium bearing steel is normalized and heat treated using a high-frequency induction annealing machine, which is prone to the following defects:

The carbide network is larger than the standard level

1. The carbide network of raw materials is serious. For this reason, we should strengthen the inspection of raw materials.

2. The normalizing temperature is low or the holding time is short. For this reason, we should choose the normalizing temperature and holding time correctly.

3. The cooling speed after normalizing is too slow. For this reason, we should speed up the cooling. Choose the cooling method wisely.

Severe decarburization, exceeding the machining allowance

1. The forging itself is seriously decarbonized. We should strengthen the decarbonization inspection of raw materials and strictly implement the forging heating specifications.

2. The normalizing temperature is high. For this reason, we should choose the normalizing heating temperature correctly.

Cracks

1. It is left on the forgings during forging. For this reason, we should strengthen the crack inspection of forgings before normalizing.

2. The cooling speed is too fast or the temperature of the cooling medium is low. In view of this, we should strictly implement the normalizing process, the cooling medium temperature should not be lower than 300-400°C, and annealing or tempering should be carried out in a timely manner.

This article briefly introduces common defects and prevention methods during normalizing of chromium bearing steel. I hope it will be helpful to your work.