大型蠕墨铸铁件的工艺试验研究

Experimental Investigation on Heavy Vermicular Iron Casting

从蠕化处理设备改进、蠕化处理包芯线成分、喂线速度、喂线加入量、合金化工艺、浇注工艺、厚大断面蠕化衰退过程研究等方面介绍了厚大断面蠕墨铸铁件的生产技术改进,并且在发动机缸体上进行了试验;选用蠕墨铸铁专用材料,控制蠕墨铸铁中的一些微量元素含量,保证加工性能。试验结果显示:厚大部位(主螺栓孔、凸轮轴孔)的蠕化率80%,薄壁部位的蠕化率85%,珠光体体积分数85%~95%,抗拉强度480~510 MPa,伸长率1.5%~3%,硬度200~215 HB,均符合RuT450材料标准要求。

The production technology improvement of the heavy vermicular iron casting was introduced including the vermicu-larizing treating equipment improvement,composition of cored-wire,core-wire injection velocity,cored-wire adding amount,alloying process,pouring process,the investigation on vermicularity degenerating process,and test was conducted with an engine cylinder block,the materials special for vermicular iron production were selected to control some trace elements contents and ensure machining property.Experiment result showed:the vermicularity of thick section(main bolt holes,camshaft hole)reached 80%,the vermicularity of thin section was of 85%,the pearlite volume fraction was of 85%~95%,tensile strength of 480~510 MPa,elongation of 1.5%~3%,hardness of 200~215 HB,all of them met RuT450 standard.