HIGH FATIGUE STRENGTH COMPONENTS REQUIRING AREAS OF HIGH HARDNESS

摘要

Metal components subject to wear or contact fatigue in a first area, and subject to bending, axial and/or torsional stress loading in a second area comprise a surface hardened, first surface layer in the first area; and a surface compressive-stress treated, second surface layer in the second area. The second surface layer has a material hardness different from, and typically lower than the first surface layer, and induced residual compressive stress to improve fatigue strength. Example components described include a gear, a cog, a pinion, a rack, a splined shaft, a splined coupling, a torqueing tool and a nut driving tool. A hybrid manufacturing process is described, including area-selective surface hardening combined with a process to add compressive stress to fatigue failure prone areas.

主权项

1. A method of manufacturing a component subject to wear or contact fatigue in a first area, and bending, axial and/or torsional stress loading in a second area, comprising:
applying an area-selective surface hardening treatment to harden a first surface layer of the component in the first area; and applying a second surface treatment, different than the surface hardening treatment, to impart residual compressive stress in a second surface layer of the component in the second area.