各种不同尺寸的铜套和铜棒,我厂需要量很大。制造这些铜套和铜棒过去都是采用砂型铸造。由于铸件比较高,用底注法冷却速度比较慢,因此铸件缩松很严重,在浇铝铁青铜时还出现集中缩孔。后虽将铸件高度改低,质量仍不能保证。因此考虑改用金属型铸造。 A variety of different sizes of brass and copper rods, I need a lot of plants. The manufacture of these copper sleeves and copper rods used to be sand cast. As the casting is relatively high, with the bottom note cooling rate is relatively slow, so the casting is very serious shrinkage, while pouring aluminum bronze also appear concentrated shrinkage. Although after the casting height is lowered, the quality can not be guaranteed. So consider using metal casting.