... )Surface finish:Oiled, zinc, nickel, chrome Motor Shell,Forging,Precision Forging Motor Shell,Forging,Precision Forging 1) Material: Carbon steel, alloy steel, stainless steel ... Treatment: Normalizing ,Annealing, Quenching, Tempering ,Solution, Passivation4) Production machine: Hot die forging presses,Friction press machine,Middle Frequency electric heater, Air hammer ...