... following. A: parts surface heating treatment, parts surface hardening, tempering, annealing, etc.B: metal brazing, high-frequency brazing, pan bottom brazing ... , Gas Carburizing, Case Hardening, Toughening, Carbo Nitriding, Core Refining, Spherodizing, Annealing, Normalizing, Stress Relieving, etc. Heat treatment is used to fabricate ...