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黄铜铸件因结晶温度范围小,收缩大,往往产生缩孔。然而在设计铸造工艺时,只注重冒口及浇注系统尺寸,而忽视内浇口的形状及引入位置。实践证明,对于黄铜铸件来说,浇注系统尺寸(包括内浇口)在相当大的范围内变化,仍可获得合格铸件。但内浇口的形状及引入位置设计得不合理,就会产生缩孔。下面介绍我厂生产黄铜铸件的实例。1 黄铜铸件的生产条件 湿型砂的组成与性能:湿型砂的组成(重量比):粘土砂(10/200):15％～30％;旧砂:70％～85％;水:4.5％～5.5％。湿压强度:3.0～5.0N/cm~2;湿透气率:>30。
Brass castings due to the crystallization temperature range, shrinkage, often produce shrinkage. However, in the design of casting process, only pay attention to riser and pouring system size, while ignoring the shape of the gate and the introduction of location. Practice has proved that, for brass castings, casting system size (including gate) in a considerable range of changes, still can get qualified castings. However, the shape of the gate and the introduction of the location design is unreasonable, it will produce shrinkage. Here is my factory production of brass castings examples. 1 Brass casting production conditions Composition and properties of wet sand: wet sand composition (weight ratio): clay sand (10/200): 15% ~ 30%; old sand: 70% ~ 85%; water: 4.5% ~ 5.5%. Wet compressive strength: 3.0 ~ 5.0N / cm ~ 2; Wet air permeability:> 30.