1, irregular shaped and pressure more and more pore structure, so that the components can be reduced to a minimum, the discharge amount of the melt increases, there is a greater capacity to capture the melting body of impurities, thus extending the life of components;2, the sand having a sharp metal edges and propolis, can easily capture the impurities and to maintain a high filtering effect in the melt, but also for the melt to generate break agglomerated particles, which had a significant effect to improve the spinning ;3, metal sand quality stainless steel raw materials, has a high compressive strength, melt pressure when the state does not occur at the highest jump bad, does not form a fine powder breakdown filter clogging of orifices.