灰铁缸体缸壁缩松缺陷的防止措施

介绍了灰铁缸体泄漏的废品率情况、出现的位置及外观特征,对该缺陷进行扫描电镜分析和金相分析,确定为晶间缩松。对该缺陷进行了大量的原因分析,包括:孕育过度、化学成分、砂芯芯头配合间隙、砂芯疏松与磨损分析、浇注温度,最终通过将铁液中w(Pb)量控制在0.001 5%以下,将w(Cr)量降低0.05%,芯头间隙控制在0.3 mm以下,适当加深封火槽,组芯、取芯时禁止拖拉砂芯,控制浇注温度在1 410~1 430℃等措施,使缸体缸孔再未出现缩松缺陷,外废泄漏问题得以解决。

Preventive Measures of Shrinkage Defects on Gray Iron Cylinder Block and Cylinder Wall

The rejection rate of gray iron cylinder block leakage,leaked location and characteristics were introduced. The defect was identified as intergranular shrinkage by SEM and metallurgical analysis. The causes this defect were about excessive inoculation,chemical composition,fit clearance between core sand and core head,the loose of sand core,wear on sand core and pouring temperature. By adjusting the w（Pb） below 5%,reducing w（Cr） by 0.05%,keeping the head clearance of sand core below 0.3 mm,deep seal groove,avoiding drag sand core and adjusting pouring temperature between 1 410-1 430 ℃ ,intergranular shrinkage can＇t be found any more and leaking problem was solved.