| 摘要 |
PURPOSE:To obtain a steel for a high strength spring excellent in hardness and toughness by specifying a compsn. constituted of C, Si, Mn, Ni, Cr, Mo, V, Nb, Al and Fe. CONSTITUTION:This is a steel for a high strength spring contg., by weight, 0.40 to 0.7O% C, 0.50 to 2.00% Si, >0.50 to 1.50% Mn, 0.50 to 2.50% Ni, 0.20 to 1.50% Cr, >0.60 to 1.50% Mo, 0.01 to 0.50% V, 0.01 to 0.50% Nb, 0.005 to 0.1O0% Al and the balance Fe with inevitable impurities and having hardness and toughness superior to those of the existing steel for a spring. The above steel can be obtd. by executing rolling after ordinary steel making, ingot making or continuous casting. This steel is subjected to post treatment such as hot coil spring forming, hardening and tempering, shot peening and setting, by which the high strength coil spring excellent in service life and settling resistance can be obtd.
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