What defects are likely to occur when heat treatment using medium-frequency induction heating equipment is used to heat the thread-rubbing board?

The thread rolling board is a special tool used for processing external threads such as taps and bolts. During work, it must withstand alternating pressure, shearing, bending and other pressures as well as impact and wear. Therefore, the quality requirements for the thread rolling board in production are very high. In order to meet the quality requirements of wire rubbing boards, many manufacturers use medium frequency induction heating equipment for heat treatment. However, during the heat treatment process, if not handled properly, some defects may occur. Today, the editor will tell you about common heat treatment defects and their countermeasures.

1. Coarse grains can easily reduce the service life of the thread rolling board, causing the thread rolling board to chip or peel off entirely. The causes and countermeasures are as follows:

(1) The quenching heating temperature is too high. Therefore, when using medium frequency induction heating equipment for quenching, we should strictly implement the heat treatment process to ensure that the quenching temperature meets the requirements.

(2) The temperature measuring instrument is inaccurate or out of control. For this reason, we should regularly check and identify the instrument and thermocouple to ensure their effectiveness.

(3) The preheating heat treatment is improper and the original structure is not refined. For this reason, we should test the spheroidization effect as required.

2. Quenching soft spots. There are quenching soft spots on the thread rolling plate, which can easily cause uneven hardness and uneven performance distribution in various parts of the workpiece, becoming the source of damage. The causes and countermeasures are as follows:

(1) The decarburized layer produced during annealing is not completely removed, so the decarburized layer must be removed before heat treatment.

(2) Oxidative decarburization occurs when heated.

3. The hardness is extremely poor. High hardness can easily cause the thread rolling plate to chip, while low hardness can easily cause wear and rotten teeth. The causes and countermeasures are as follows:

(1) The quenching temperature is too high or too low. Therefore, when using medium frequency induction heating equipment for quenching heat treatment, it should be ensured that the quenching temperature meets the requirements.

(2) Tempering temperature is low or high. Like quenching, during heat treatment, the tempering temperature should be ensured to meet the technical requirements.

The heat treatment process is a key factor affecting the quality of the heat treatment of the workpiece. Therefore, when we perform process operations, we should strictly follow the requirements to avoid unnecessary defects.