Heat Treatment Soft annealing °CCoolingHardness HB 650-700slowlymax. 280 Stress-relief annealing °CCooling 630 - 650Furnace 1st pre-heating °C2nd and 3rdHardening °CQuenchingTempering °CHardness after Teperature HRC up to approx. 400 in an air-circulating furnace780 and 10001190 - 1230Saltbath, at least 520 °C Oil ,Airat...