| The present work is concerned with the effects of molding material, gating system, melting condition & pouring temperature on the soundness of Cu-alloy castings. These effects were evaluated by the measurements of solidification rate, leakage, chemical composition and mechanical properties. Because the soundness of castins not only depend on solidification rate, chemical composition and mechanical properties, but also depend on leakage of hydraulic pressure. The castins were poured in three different mold; natural bonded sand, synthetic sand, and resin coated sand. A 5㎏ melt of each alloy was made by degassing with Cu-P alloy in cryptol furnace under various conditions to determine the effects mentioned above. On the basis of these experimental results, favorable condition of casting process was proposed as follows. 1. Synthetic sand mold was more effective than the others. 2. Unpressurized gating system having screen at juncture between the runner and ingate would be more desirable in order to avoid the turbulence and non-metallic inclusion such as dross and sand. 3. When scraps were only charged degassing was desirable after melting under oxidizing condition. This reason may be rationalized by equilibrium curve of oxygen and hydrogen proposed by Allen & Hewitt. 4. The optimum pouring temperature was found to be 1150℃. |
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