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Heat Treatment Method For Slewing Bearing
- Nov 20, 2018 -

First, the basic knowledge of induction hardening:

1. Surface quenching refers to a heat treatment method in which the surface layer is austenitized and quenched to enhance the surface of the part by rapid heating without changing the chemical composition and core structure of the steel.

2, the purpose of surface quenching: the surface has high hardness, wear resistance and fatigue limit, the core has sufficient plasticity and toughness under the condition of maintaining a certain strength and hardness. That is, the table is hard and tough. Suitable for parts subject to bending, torsion, friction and impact.

3. Basic principle of induction hardening: The workpiece is placed in the inductor (coil). When an alternating current of a certain frequency is passed into the inductor, an alternating magnetic field is generated around the workpiece. The electromagnetic induction of the alternating magnetic field causes a closed induced current ------ eddy current in the workpiece. The high-density current of the surface of the workpiece is converted into heat energy, which raises the temperature of the surface layer, that is, achieves surface heating. The higher the current frequency, the greater the difference in current density between the surface layer and the inside of the workpiece, and the thinner the heating layer. Surface quenching can be achieved by rapidly cooling after the temperature of the heating layer exceeds the critical point temperature of the steel.

4. Commonly used current frequencies are:

   A, high frequency heating: 100-500KHZ, commonly used 200-300KHZ, hardened layer depth of 0.5-2.5mm, suitable for small and medium-sized parts.

   B, medium frequency heating: 500-10000HZ, commonly used 2500-8000HZ, hardened layer depth 2-10mm, suitable for larger diameter shafts, medium and large gears, etc.

   C, power frequency heating: current frequency is 50HZ. It adopts mechanical power frequency heating power supply equipment, and the hardened layer depth can reach 10-15mm, which is suitable for surface quenching of large diameter workpieces.