| 摘要 |
PURPOSE:To manufacture a copper or copper alloy casting which is free from a surface defect, without causing a sudden rise of a cost of a raw material by executing the casting by using a copper or copper alloy molten metal in which Ca is a low content percentage. CONSTITUTION:A copper or copper alloy casting which is free from a surface defect is obtained economically by casting a copper or copper alloy molten metal of 0.0002-0.015wt% Ca content percentage, which has been obtained by forming a molten raw material by mainly electrolytic copper and adjusting a compounding quantity of a scrap, or bringing Ca to a removing treatment by using a filtrating method, etc. by a filter at the state of melting. The reason why said Ca content percentage has been limited is because it is necessary to use the electrolytic copper only in order to set it to <0.0002%, a sudden rise of a cost is caused, and if it exceeds 0.015%, the generation rate of the surface defect increases.
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