消失模铸造中冲砂及其模料和涂料夹杂的预防

Prevention of Sand Washing,Pattern Material Inclusion and Coating Inclusion in Lost Form Castings

分析了消失模铸造中铸件冲砂及其模料和涂料夹杂缺陷产生的原因和特点,结合生产实践,提出了改进措施:采用专制的铸件白模用材料制作浇注系统;整体组建模型簇;应用室温强度足够的消失模铸造涂料;确保浇注前浇口杯没有浮砂、尘土和杂物;合理地选择浇注系统静压头、浇注温度、负压度、干砂粒度等工艺参数。通过这些措施,有效地预防或减少了冲砂、模料和涂料夹杂缺陷的产生。

The reasons causing sand washing,lost foam pattern materials inclusion and coating inclusion of lost foam castings and the defects characteristics were analyzed,and,combined with the production practice,the improvement measures were proposed as follows：adopting special lost foam materials to make the gating system pattern;assembling the patterns cluster as a whole;using coating which has sufficient room temperature strength for the loss foam pattern;ensuring no scattered sand,no dust and no other impurities in the pouring basin before pouring;properly choosing the process parameters such as the static pressure head of the gating system,pouring temperature,vacuum degree,and granularity of dry sand etc.By above measures,the sand washing,pattern materials inclusion and coating inclusion defects have been effectively prevented or reduced.