一、寻找煤粉代用品的必要目前国内外防止铸铁件粘砂比较有效的方法,是在型砂中加入含碳附加物,如煤粉、重油、沥青等,其中应用最广的是煤粉。这是因为煤粉来源广、成本低,并有防止夹砂、皮下气孔等优点。关于煤粉能防止粘砂的机理有如下几种说法:(1)气膜理论 First, looking for the necessary substitute for coal At present, the domestic and foreign to prevent cast iron sticky sand more effective method is to add carbonaceous additives in the sand, such as coal, heavy oil, asphalt, etc., of which the most widely used is pulverized coal. This is because the wide source of pulverized coal, low cost, and prevent sand, subcutaneous pores and other advantages. There are several theories about the mechanism that pulverized coal can prevent sticking sand: (1) Gas film theory