Origination of sand flushing in EPC（evaporate pattern casting） was analyzed by mathematical theory. The sand flushing defects between the sprue and pouring cup in EPC can be prevented by preventing sealed plastic film from high temperature heat sources and by sealing joint of pouring cup and the sprue with refractory mortar containing high temperature binder to take a whole shape. The sand flushing defects in bottom of the sprue can be eliminated by sealing around refractory brick for bottom of the sprue refractory mortar. The sand flushing in the sprue and in runner as well as in joint between ingate and runner can be prevented by thickening coating on the ingate

sealing joint with the refractory mortar or brushing rapidly drying coating as well as drying wet sand and vacuum pumping ahead of 3

5

minutes.