For cast steel, the main raw materials include scrap steel, ferrosilicon, manganese iron and aluminum alloy deoxidizer, and the main auxiliary material is silica sand. The process of mixing furnace and proportioning is an important link in molten steel melting, and the proportion of material composition has an important impact on the mechanical properties of the products. Strict control of raw materials can reduce or avoid the occurrence of shrinkage cavity and porosity, and the selection of good auxiliary materials can improve the surface quality of products.
The quality requirements of silica sand shall be in accordance with the standard GB / T 9442-1998. The following contents shall be inspected for silica sand by molding sand detector: suitable particle shape: round sand 30 ~ 80%; particles are spherical or nearly spherical, with smooth surface and no redundant edges and corners. 15 ~ 25% of polygonal sand particles are polygonal, and most of them are obtuse angle. The sharp angle sand should be controlled below 5%, and the particles should be in sharp angle shape with more acute angles. Mud block, stone, steel slag, plastic and other impurities are not allowed in silica sand to avoid affecting molding sand.