硅对铸态厚断面高韧性球墨铸铁组织及性能的影响.pdfVIP

维普资讯 学兔兔 铸 造 Feb．2OO8 · 114· FOUNDRY Vof．57 N0．2 硅对铸态厚断面高韧性球墨铸铁组织及性能的影响 孙玉福 ，于广文 ，崔金鹤 ，洪书淮 ，申云霄 ，余颂青 (1，郑州大学材料科学与工程学院，河南郑州450002；2．郑州纺机铸造有限公司，河南郑州450002) 摘要：研究了硅对铸态厚断面高韧性球墨铸铁组织及性能的影响。试验结果表明，硅主要分布于基体中，富集于奥氏 体壳局部区域时，降低奥氏体壳的熔点，延长石墨自由生长的时间，造成石墨畸变。在铸件壁厚为100 rfhn，树脂砂工 艺条件下，硅含量为2．0％～2．5％时，石墨球化等级2～3级，球径等级 7级，基体为铁素体。抗拉强度大于400MPa，伸 长率大于20％，一20℃时的冲击韧度在16 J／cm 以上。硅含量达到2．9％时，易产生开花状石墨和碎块状石墨，铸件的性 能严重下降。 关键词：硅；铸态厚断面高韧性球墨铸铁；组织；性能；畸变石墨 中图分类号：TG143．5 文献标识码：A 文章编号：lOOl一4977(2008)02—0l 14—03 Effect of Silicon on Microstructure and Properties of As—Cast Heavy Section Ductile Iron with High Toughness SUN Yu-fu’，YU Guang-wen’，CUI Jin—he’，HONG Shu—huai ，SHENG Yun—xiao ，YU Song．qing (1．School of Material Science and Engineering，Zhengzhou University，Zhengzhou 450002，He’nan， China；2．Zhengzhou Te)(tile Machinery Foundry Co．，Ltd，Zhengzhou 450053，He’nan，China) Abstract：The effect of silicon on the microstructure and properties of as—cast high toughness heavy section ductile iron was studied．The results showed that silicon mainly distributes in the matrix．and when silicon iS rich in the partial regions of austenite shell。it decreases the melting point of austenite shell and prolongs the free growth-time of graphite，therefore resulting in the distortion of graphite．For the casting of section thickness 1 00 mm and cast by furan resin bonded sand．the matrix iS ferrite when silicon content iS 2．0％一2．5％．and the spheroidization grade and the graphite grade are grade 2．3 and 6．7，respectively；the impact toughness at一20℃ exceeds 1 6 J／cm2，the tensile strength iS higher than 400 MPa an