| 摘要 |
PURPOSE:To form uniform bainite structure and to produce a graphite cast iron product having high strength and high toughness by subjecting the as-cast graphite cast iron product added with alloy elements for improving hardenability and toughness to shot peening. CONSTITUTION:Stress is exerted by a treatment such as shot peening, just prior to bainite transformation, to the cast iron prepd. by adding and incorporating at least one kind among <1.0% Mo, <1.5% Cu, <1.0% Cr, and <5% Ni in order to improve the hardenability and toughness to the graphite cast iron consisting of the basic compsn. contg., by wt%, 2.5-4.5% C, 1.5-3.5% Si, <0.8% Mn, <0.1% P, and <0.15% S in the stage of converting the as-cast base to the bainite structure. The uniformly strained bainite structure is obtd. and the high-strength high-toughness graphite cast iron product having excellent mechanical properties is obtd.
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