Stamping Part 1.Material:steel,stainless steel.brass,aluminum,brass.cooper. carbon steel. 2.Surface:zinc ... plating ,powdered,pas Torsion Bar Spring 1.Material:steel,stainless steel.brass,aluminum,brass.cooper. carbon steel. 2.Surface:zinc ... , Physio-chemicalLabora tory 9Production lines1) The lost-wax casting of stainless steel and heat-resisting steel with silica-gel shell made ...