All components hardened in RENK’s hardening shop are typically blast cleaned. This step is carried out using a manually operated and a semi-automatic glad bead blasting system, two rotary-disk impeller blasting machines, and a blasting cabinet for very large components. Glass beads and hardened steel balls are used as the blasting media. Compressed air or impellers are used to accelerate the blasting medium against the material undergoing blasting, which cleans and compresses the component’s surface. Following blasting, the heat treated material is free of residues such as insulating pastes, scale, oil, and soot.

Blast cleaning with steel balls also introduces substantial residual stress in the component surface, which is accompanied by hardening of the surface. This leads to a measurable increase in hardness and, in the case of toothed parts in particular, to a noticeable increase in the strength of tooth flanks and tooth roots.