Low-carbon Steel Kid- carbon Steel High- carbon Steel Stainless Steel Alloy Steel Titanium Alloy Hard steel: carbon(%) : 0.55~0.8 tensile(kgf/mm2) : 62~72 function : saw, screws, wheel ring Super hard steel: carbon(%) : 0.81~1.70 tensile(kgf/mm2) : 大於72 function : blade, screw mould, pressing head