reducing expansion stress of the moulding sand and increasing wet tensile strength of moulding sand are the main measures to prevent scab defect.
防止夹砂缺陷的主要措施是降低型砂的膨胀应力和提高型砂的热湿拉强度。
according to the mechanism principle, the causes of occurring scab easily on big castings and the influences of wet tensile strength on scab were discussed.