Annealing, normalizing, quenching, tempering and case hardening processes
Heat 30-50°C above A3, slow furnace cool. Softens, relieves stress. Cool at 10-30°C/hr.
Heat 40-60°C above A3, air cool. Refines grain (ASTM 7-8 vs 4-5 forged).
Media: water, oil, polymer, air. 0.3%C → 45 HRC, 0.6%C → 62 HRC. Temper: 150-650°C.
Carburizing: 900-950°C, 0.5-2mm. Nitriding: 500-550°C, 1000-1200 HV. Induction hardening.