... and good performance steels. Heat Treatment:- Anneal: 840-860°C, Hardness: 207-255HB- Quenching: 980-1040°C, oil cooling or ... air cooling - Tempering: 510-540°C, and tempering twice- Hardness: 60-64HRC- High temperature oxidation resistance, high anti-rust after ... quenching and polishing, light deform under heat treatment. - Hot hardness will increase after twice hardening, which will be proper for ...