【摘要】 系统研究了不同含量的硅对Mn Si Cr B系贝氏体铸钢强韧性的影响。结果表明 ,Si量在铸钢中为 1 6%～ 2 4%时 ,脆性的渗碳体被韧性的残留奥氏体代替 ,得到无碳化物贝氏体 ,其组织特征为含碳过饱和的板条贝氏体铁素体和分布在其中的薄膜状富碳残留奥氏体。在其硬度基本保持不变的情况下 ,冲击韧度显著提高 ,由 5～ 6J/cm2 提高到 8～ 1 2J/cm2 (U型缺口 )和由1 2～ 1 3J/cm2 提高到 2 0～ 30J/cm2 (无缺口 )。但是 ,Si增加铸钢的枝晶偏析和块状残留奥氏体 ,当钢中硅量达到 2 4% ,铸钢硬度明显下降。更多还原

【Abstract】 WT5”BZ][ST5”BZ]The effects of Si on the lower medium carbon Mn Si Cr B bainitic cast steels have been investigated systematically The results show that the carbide free structure,which is composed of fine bainite ferrite and residual austenite film,is obtained in high Si(1 6%～2 4%)steels owing to brittle cementite being replaced by ductile austenite film Compared with that of the low Si bainitic cast steels, the impact toughness of high Si bainitic cast steels increase effectively while maintaining the same hardness level The impact toughness rises from 5～6J/cm 2(U notch),and 12～13J/cm 2(without notch)for low Si bainitic cast steel to 8～12J/cm 2(U notch),and 20～30J/cm 2(without notch) for high Si bainitic cast steel However,since dendrite segregation and residual blocky austenite increase with the Si increasing,the hardness of high Si bainitic cast steel decrease apparently when the Si content is up to 2 4%更多还原