Steel No. OPTIMAX suppliers: Assab steel type plastic mold steel standards and the latest features Price Comparison 420 (optical grade mirror steel) factory condition and hardness of a typical annealing to about HB 215 major chemical composition analysis results (%) Composition C Si percentage of Cr, Mn 0.38 V 0.8 13.6 0.5 0.3 Steel properties: a high degree of purity and mirrors, anti-rust anti-acid ability of excellent general purpose steel less heat deformation: anti-acid high, especially for high requirements and injection optical mirror mode 1025 Product of hardened cooling oil temperature, air tempering temperature and hardness were 180 ℃ 225 ℃ 300 ℃ 570 ℃ 54 53 - -