The Surface Strengthening of Bearing Steel
Bearing steel is a type of steel mainly used for manufacture bearings, bearing rings, bearing raceways and other parts, it is impregnated with nitrogen and carbon, it is also called Nitrogenized bearing steel. Bearing steel has good plasticity and fatigue performance, but it has poor wear resistance, so it is necessary to strengthen the surface to make it better suit for machines. In this article, we discuss several common methods to strengthen the surface of bearing steel.
The most common way of surface strengthening of bearing steel is the carburizing and the nitriding. This can enhance the wear and fatigue resistance of the bearing steel with increasing its hardness on the surface. Carburizing is a process that uptake carbon into the surface of the steel during heating and quencning, thus resulting in a higher carbon content in the area near the surface. It also helps to increase the hardness as well as the wear resistance. The nitriding is also similar to that, however, along with the carbide particles absorbed by the steel, it also adsorbs nitrogen particles, and thus imparting more wear resistance and more hardness to the surface.
Another method of surface toughening is shot peening, it is a type of physical treatment that introduces strain hardening mechanisms into the surface of the bearing steel. By this method, tiny particle bombardment along with carefully-controlled labor pressure and velocity can cause the surface of the bearing steel to compress and strain harden. This helps to increase its fatigue life, wear resistance and other properties of the bearing steel component.
By using suitable processes such as Flame Hardening, Induction Hardening and Laser Harden, it provides a customization of surface hardening effects as well as in depth hardening solutions. All these processes increase the surface hardness and thereby reduce the wear of the bearing steel due to their heat treatment induction.
Most of the surface hardening processes have associated its own issues related to thermal stress, distorted surfaces, and thermo- electrical effects. Careful control of the parameters is essential for the good working of these processes.
In conclusion, the surface hardening of bearing steel is necessary to increase its wear resistance, fatigue life and thereby extend its service life. Surface hardening processes are quite effective and considered as a cheap and safe way to improve the bearing steel parts. But, one should always bear in mind that, as with all hardening processes, careful monitoring and optimization of conditions is critical to get desirable results.
