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Length dimension affecting induction hardening

How to determine the depth of the high-frequency quenching length? There are different requirements for the different customers and different workpieces of the quenching hardening layer. The high-frequency quenching length dimension will have no effect, and the high-frequency quenching depth cannot reach the reason. What are the following? The following small series will take you to find out.


High frequency quenching

High-frequency quenching is mostly used for surface quenching of industrial metal parts. It is a metal heat treatment method that produces a certain induced current on the surface of the workpiece, rapidly heats the surface of the part, and then rapidly quenches. Induction heating equipment, that is, equipment that inductively heats a workpiece for surface hardening. The principle of induction heating: the workpiece is placed in the inductor. The inductor is usually a hollow copper tube with input intermediate frequency or high frequency alternating current (1000-300000Hz or higher). The alternating magnetic field generates an induced current of the same frequency in the workpiece. The induced current is uneven in the distribution of the workpiece, strong on the surface, and weak inside, to the core close to 0, using this skin effect The surface of the workpiece can be heated rapidly, and the surface temperature rises to 800-1000 ° C in a few seconds, while the temperature rise of the core is small.
 

Advantages of high frequency quenching and ordinary heating quenching

1. The heating speed is extremely fast, which can expand the A-body transition temperature range and shorten the transition time.

2. After quenching, the surface of the workpiece can be obtained with very fine cryptocrystalline martensite, and the hardness is slightly higher (2~3HRC). Low brittleness and high fatigue strength.

3. The workpiece processed by the process is not easy to be oxidized and decarburized, and even some workpieces can be directly assembled after being processed.

4, hardened layer depth, easy to control operation, easy to achieve mechanization, automation.

5, the flame surface is heated and quenched

A workpiece subjected to alternating loads such as torsion and bending requires the surface layer to withstand higher stress or wear resistance than the core. It is necessary to strengthen the surface of the workpiece, and is suitable for steel with a carbon content of We = 0.40 to 0.50%.


The effect of high frequency quenching on the surface has an effect

The influence of the size of the high-frequency quenching is relatively small, and the products after heat treatment generally have deformation. The control of the deformation is generally not found. After a large number of experiments, the law can be found, but it is not determined.


High-frequency quenching is mostly used for surface quenching of industrial metal parts. It is a metal heat treatment method that produces a certain induced current on the surface of the workpiece, rapidly heats the surface of the part, and then rapidly quenches. Induction heating equipment, that is, equipment that inductively heats a workpiece for surface hardening. The principle of induction heating: the workpiece is placed in the inductor. The inductor is usually a hollow copper tube with input intermediate frequency or high frequency alternating current (1000-300000Hz or higher). The alternating magnetic field generates an induced current of the same frequency in the workpiece. The induced current is uneven in the distribution of the workpiece, strong on the surface, and weak inside, to the core close to 0, using this skin effect The surface of the workpiece can be heated rapidly, and the surface temperature rises to 800-1000 ° C in a few seconds, while the temperature rise of the core is small.



What are the reasons why the high frequency quenching depth is not reached?

For example, a shaft is quenched, the material is 40Cr, and the required depth is 7~10mm. If high frequency quenching equipment is used, the following problems will occur:

The quenching depth is not reached, and internal cracks appear, and the process requirements that need to be achieved cannot be achieved.


What are the reasons for this phenomenon? Haituo Electromechanical has been analyzed as follows:

The workpiece is quenched by high-frequency induction heating equipment. The required depth of the workpiece is 7~10mm. If the surface temperature is too high when heated once, there will be cracks. If it is heated for a long time, it cannot be realized, and the cost is too large. Even if high frequency can be used to achieve such a depth, it is estimated that the surface has been melted by one heating, and even if multiple heating is used, it is not guaranteed. The reason is that the high frequency is characterized by induction heat treatment of the metal surface, using the skin effect, generally less than 3mm should be better control. The high-frequency current penetration depth is determined by its frequency, the current penetration is insufficient, and the heating time is too long. Due to the skin effect, the surface temperature is too high, causing quenching cracking.


  Solution:

Such quenching depth, Haituo Electromechanical recommends the use of medium frequency induction heating power supply, high frequency of intermediate frequency, deep quenching layer, using the overall quenching process, can meet the requirements of the process.

The above examples can be seen, the importance of choosing the right frequency of the machine, reasonable processing methods, etc., high-frequency quenching length, high-frequency quenching, you can try to reduce the power factor during quenching, that is, the temperature rise time is longer, so there is Conducive to deepen the hardening depth of the workpiece.
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