| 摘要 |
PROBLEM TO BE SOLVED: To obtain a plastic die material for a lens having excellent general properties required for a die such as weldability, proof stress and toughness, further nearly free from the generation of pinholes and fine pits and having particularly excellent specular properties, and to provide its production method. SOLUTION: This plastic die material for a lens has a composition containing, by weight, 0.10 to 0.20% C, 0.20 to 1.5% Si, 0.20 to 2.0% Mn, <=0.030% P, <=0.020% S, 1.0 to 3.0% Cr, 0.1 to 0.5% Mo, 0.05 to 0.3% V, 0.002 to 0.030% s-Al and <=0.0030% O, and the balance Fe with inevitable impurities, the total content of inclusions is <=0.053%, also, the average value of the maximum width diameter of the inclusions is <=15μm, and further, its hardness is 28 to 38 HRC.
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