Importance of Heat Treatment for Tapered Roller Bearing

Jul 05, 2021

When the material of the tapered roller bearing is determined, the heat treatment technology is the key technology to determine the service life of the bearing. In the past ten years, the conventional heat treatment of bearings has developed rapidly, and the heat treatment of bearings with ordinary precision and general life can fully realize mass production.

For a long time, the heat treatment of high-carbon chromium bearings adopts martensite quenching and low temperature tempering, and the bainite quenching and tempering process is only used in railway passenger cars and some rolling mill bearings.

Surface modification mainly includes low-temperature ion permeation, carbonitriding, ion nitriding, surface coating, ion implantation, and laser high-energy beam surface heat treatment. Low-temperature seepage can improve the self-lubrication of the bearing and reduce the friction coefficient of the bearing; carbonitriding, ion nitriding, etc. can increase the surface hardness and increase the wear resistance .

The technical progress in the annealing process of tapered roller bearings is mainly reflected in energy saving and temperature uniformity. Waste heat utilization annealing, double-row double-layer energy-saving annealing furnaces have been adopted in batches in the bearing industry. The annealing quality is obviously improved and the annealing is uniform. At the same time, the energy saving is at least 25% compared with before, and the lowest can reach 110 degrees. The annealing power consumption is basically equivalent to that of foreign countries. However, the degree of refinement of the structure after annealing is not fine enough. The refinement and uniformity of carbides have an impact on the service life of the bearing.

After forging tapered roller bearings, the single refinement process and the double refinement process have not been applied in industrial batches. It is estimated that a technological breakthrough will be achieved soon. It is reported that the double refinement can increase the life of the bearing at least twice. However, the double refinement process is risky, and the key technology of the process has been broken. Industrial practice is advancing, and the double refinement process will also be promoted in high-end bearings in the near future. The double thinning process can not only increase the life of the bearing, but also improve the dimensional stability of the bearing operation.