铸型在浇注铁水后,型(芯)砂直接和液态金属接触,处于非常恶劣的条件下。因此,要求型(芯)砂不仅具有较好的高温性能,以防止铸件表面缺陷,而且应尽量降低粘结剂的加入量,以减少发气量而避免气孔缺陷,改善落砂清理性能,降低铸件成本。尤其是树脂砂,对这一要求更为突出。于是,需要寻找粒形圆,表面光洁、纯净的硅砂作为树脂砂的原砂。然而,天然砂粒表面总粘附着一层泥土和水化物膜,把砂粒和粘结剂隔开。并吸掉部分 After pouring hot metal mold, type (core) sand and liquid metal directly in contact with the very poor conditions. Therefore, the requirement (core) sand not only has good high temperature performance, in order to prevent castings surface defects, and should minimize the amount of binder added to reduce gas evolution and to avoid porosity defects, improve the performance of sand removal and reduce the casting cost. In particular resin sand, this requirement is more prominent. So, you need to find the grain round, smooth surface, pure silica sand as resin sand of the original sand. However, the surface of natural sand adheres to a layer of soil and hydrate film, separating the sand from the binder. And sucked away