How to effectively prevent raceway quenching cracks in slewing bearings

2019-08-16

Slewing bearingThe raceway of (slewing bearing) needs the process of quenching. After quenching, the hardness of the slewing bearing raceway is increased and the wear resistance of the raceway is increased. However, improper quenching is prone to quenching cracks. Once cracks occur, the slewing ring will be caused in most cases. The scrap of the bearing has important meanings due to the prevention of quenching cracks. Prevention of quenching cracks can be grasped from the following aspects.

1. Choose a reasonable quenching method

Correct and reasonable selection of quenching methods according to the structure and characteristics of the slewing bearing, skill requirements, structural design, and the nature of the workers can greatly reduce or avoid quenching cracking accidents.

2. Other ways to avoid quenching cracks

3. Reasonably arrange the process line

Once the material, structure and technical conditions of the slewing ring are confirmed, the craftsman must conduct a process analysis to confirm a reasonable process route. Properly arrange the sequence of preparation processing, heat treatment and thermal processing. This is the primary effective way to prevent the cracking tendency of the slewing bearing track after heat treatment.

4. Properly confirm the heating parameters

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

5. Selection of quenching medium

The selection of quenching medium should consider the following factors:

(1) Slewing bearing characteristics: the chemical composition of the steel (phase change characteristics), the cross-sectional dimensions of the workpiece, the geometry of the workpiece, the surface roughness and appearance, the arrangement and concentration of the raceway during quenching, etc.

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

6. Carry out product design correctly

The design should be based on the working conditions and application requirements of the slewing bearing, the cross-sectional dimensions of the slewing bearing should be reasonably designed, the materials should be selected correctly, and the structural design should be as satisfied as possible with the heat treatment process for the structure of the slewing bearing.