FeS对复合铸铁石墨形态分布规律的影响

Effect of Fe S on distributing regularity of graphite morphology of composite cast iron

通过在铸造涂料中引入（5-40）%FeS,利用FeS的蠕化衰退作用,在蠕墨铸铁局部表层制备1-5 mm灰铸铁。综合运用OM,EPMA和激光热导仪分析了涂料中FeS含量对铸件石墨形态分布规律的影响机理及其对铸件不同部位的导热系数的影响规律。结果表明：随着Fe S含量增大,铸件表层灰铸铁的厚度先逐渐增大直至平衡;从铸件表面到内部,石墨形态由A型逐渐转变为D型,最后到蠕虫状石墨;且残留的S含量逐渐降低,残留的Mg含量逐渐升高,Mg与S形成化合物,降低了铸件表面的残余Mg含量,发生蠕化衰退,形成灰铸铁。从铸件表面到内部相同温度下的导热性能逐渐降低。

A gray cast iron with thickness of 1-5 mm was prepared on the local surface layer of compacted graphite cast iron by adding（5-40） % Fe S in the casting coating.The influence mechanism of Fe S content on the graphite morphology distribution and its effect on different parts＇ thermal conductivity coefficient of the casting were analyzed by means of optical microscope（OM）,electron probe microanalysiser（EPMA）,laser heat conductivity.The results show that with Fe S content increasing,gray cast iron thickness of the casting surface layer gradually increases first and then reaches equilibrium; from the outer to the internal layer of casting,the graphite morphology gradually changes from A-type to D-type,and finally to the vermicular graphite,and the residual S content decreases,the residual Mg increases gradually; the formation of Mg and S compounds decreases the residual Mg content in the surface of the casting lead to vermicularizing recession,then forms gray cast iron.The thermal conductivity decreases gradually from the surface to the interior of the casting at the same temperature.