| 摘要 |
PURPOSE:To improve the impact strength and toughness of the titled spheroidal graphite cast iron by adding specified amounts of C, Si, Mn and Mg and specifying the amounts of retained austenite and bainite. CONSTITUTION:This high-silicon bainitic spheroidal graphite cast iron consists of, by weight, 3.0-4.5% C, 2.5-4.5% Si, 0.2-1.0% Mn, 0.02-0.10% Mg and the balance Fe and contains 20-80% retained austenite and 20-80% bainite. The spheroidal graphite cast iron has an Si reinforced bainite structure combined with retained austenite having high toughness by setting about 850-950 deg.C and 0.5-3hr as conditions during austenitizing and about 200-500 deg.C and 0.5-10hr as conditions during isothermal heat treatment. The impact strength of the spheroidal graphite cast iron is increased, and the cast iron is very practical especially as a material for automotive parts.
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