Duplex hardened cage pilot surface for bearing ring

A method of forming a bearing ring, the method comprising:

• (i) applying a heat treatment to the bearing ring formed from M50NIL steel, such that a base material hardness within 0.6 mm of an outer surface of the bearing ring has a Vickers hardness of 670;
• (ii) pre-grinding the entire bearing ring;
• (iii) masking portions of the bearing ring except for a raceway and a predetermined area directly adjacent to the raceway, wherein the predetermined area includes radially extending shoulders forming cage pilot surfaces and rolling element guide surfaces;
• (iv) applying a nitriding treatment to the bearing ring to form a case-hardened outer layer surface on the raceway and the predetermined area, such that the raceway and the predetermined area have a Vickers hardness greater than 800 HV0.3 at a depth of less than 0.3 mm from an outer surface of the raceway and the predetermined area;
• and
• (v) applying a finishing treatment to the bearing ring, such that a thickness of the case-hardened outer layer surface is reduced by 20%-40%.