Coal powder, Brand Name : HongYue, Packaging Type : Black

Mechanism of coal dust preventing sand sticking
1, in molten metal under the action of high temperature mold surface of pulverized coal produced a large reduction of the gas, to prevent oxidation of the molten iron, and iron on the surface of iron oxide reduction, reduction of metal oxides and sand the possibility of chemical reaction. In the cavity, the reducing gas mainly comes from the volatile matter of coal powder, and also includes the hydrogen gas generated by the water gas reaction between carbon and water at high temperature.
2, after the heating of coal began to soften, with plasticity. If by the beginning of softening to curing between relatively wide temperature range and time long, buffer quartz grains in the heat, the temperature interval and the formation of expansion stress, which can reduce the casting defects caused by thermal expansion of the sand.
3, the pulverized coal after heated gas, liquid and solid three-phase colloid, colloid volume expansion part jam pore between grains, molten iron is difficult to penetrate.
4, pulverized coal in the heat generated by the carbon hydride (mainly aromatic volatile points in 650 DEG to 100 DEG C high temperature, in a reducing atmosphere in the occurrence of gas phase pyrolysis and on the interface of the liquid metal and mold precipitation layer with fine crystalline carbon luster, known as lustrous carbon. This layer of bright carbon without sand infiltration and hard to penetrate to the sand pore in molten iron, resulting in smooth surface castings.