The raceways are selectively hardened to the required surface and depth necessary to transmit high stresses imposed during operation of the equipment. 

Following picture reflects the  typical hardness patterns of four-point ball (SCB-RK, SCB-HS, SCB-HT, SCB-MT, SCB- KH, and SCB- XT Series) and cross roller (SCB-XR Series) bearings.  Multiple row bearings (SCB-DT and TR Series) receive similar  treatment in their highly stressed raceways. 

In one location  around the raceway, there is an unhardened area referred  to as the hardness gap or “soft spot.” This area is relieved to  minimize the ability of the rolling element to apply stress on  it.