What are the methods to prevent quenching crack of slewing bearing?

The quenching crack of slewing bearing refers to the crack produced in the process of quenching or in the process of placing at room temperature after quenching. The latter is also called aging crack. There are many reasons for quenching crack of slewing bearing. When analyzing quenching crack, it should be distinguished according to crack characteristics.

So how can we prevent the quenching crack of slewing bearing?

In order to prevent the quenching crack of slewing bearing, the following measures can be taken:

1. Correct product design of slewing bearing

The design should be based on the working conditions and use requirements of slewing bearing, reasonable design of cross-section size of slewing bearing, appropriate selection of materials, and structural design to meet the requirements of heat treatment process on slewing bearing structure.

2. Reasonable arrangement of process route

Once the material, structure and technical conditions of slewing bearing are determined, the technologists shall analyze the process and determine the reasonable process route. Correctly arrange the sequence of preparation, heat treatment and heat treatment. This is the main effective way to prevent the cracking tendency of slewing bearing track after heat treatment.

3. Selection of quenching medium

The selection of quenching medium should consider the following factors:

(1) Slewing bearing characteristics: chemical composition (phase transformation characteristics) of steel, section size, geometric shape, surface roughness and surface state of workpiece, arrangement and density of raceway during quenching, etc.

(2) Quenching method: including quenching bath liquid, stirring speed, flow direction and solution concentration.

4. Choosing reasonable quenching method

According to the structure and characteristics of slewing bearing, technical requirements, structural design status, worker quality and so on, the correct and reasonable selection of quenching method can greatly reduce or avoid quenching crack accidents. Slewing bearing

5. Proper determination of heating parameters

In the production of heat treatment of slewing bearing track, improper heating is the main factor causing the cracking of quenched slewing bearing raceway. Therefore, the heating parameters such as heating medium, heating speed, heating temperature and holding time should be correctly selected and designed.

6. Other measures to prevent quenching crack

Tempering in time after quenching (generally low temperature tempering) and local bandaging for thin wall treatment of complex shape parts can also effectively prevent cracks.