... mainly used to manufacture cushion spring, clockwork spring, oil pump speed adjusting spring, plunger spring, absorber spring 65Mn Spring Steel (1)Specification:φ5.5 ... used to manufacture cushion spring, clockwork spring, oil pump speed adjusting spring, plunger spring, absorber spring, clutch spring and brake spring etc. (3) ... limit and tensile ratio, as well as accurate shape and dimension.