AISI420
420 quality stainless steel can be hardened by many heat treatments like high carbon steel. It contains at least 12% chromium (Cr) and this alloy is sufficient for corrosion resistance. It has good softness in annealed condition, but it has the ability to get 50 Rockwell hardness by heat treatment. For best corrosion resistance it must be hardened and gets it surface cleaned or polished.