覆砂铁型铸造气缸体气孔缺陷的防止措施

摘要

分析了采用覆砂铁型工艺生产4缸气缸体产生气孔缺陷的原因,认为该缺陷属于侵入性气孔,采取以下改进措施:(1)在铁型清理工位和射砂工位之间增加一道铁型加热工序,以提高铁型温度;(2)使用角形系数较小、偏中性的再生砂代替角形系数较大、偏碱性的擦洗砂,以降低砂芯的树脂加入量;(3)改进浇注操作,提高铁液压力头,增大内浇道厚度2 mm,从而提高浇注时铁液流速.生产结果显示:气孔废品率由原来的11.31％降至0.45％.%The reasons of porosity defects on sand coated iron type 4 cylinder block casting were analyzed.It was believed that the defects were result of invasive pores.The following measures were taken to improve:(1)Increase a sand iron type heating step between iron-based clean-up station and shooting station to raise the temperature of the iron type.(2)In order to reduce the amount of resin,use small angular coefficient,partial neutral reclaimed sand instead of larger angular coefficient,alkaline scrub sand.(3)Improve the casting operations,improve liquid iron head pressure,increasing the thickness of the inner runner by 2 mm in order to increasing the flow rate of the liquid cast iron.Production results showed:porosity scrap rate dropped from 11.31％ to 0.45％.