| 摘要 |
PURPOSE:To prevent the degradation in dimensional accuracy of ingots and generation of star cracks and to prolong the life of a mold made of copper or copper alloy by coating the specific range in the lower part of the inside surface of the mold base body with a protecting film. CONSTITUTION:A range of 1/5-4/5 of the entire height from the bottom end part of the inside surface of a mold base body made of copper or copper alloy is coated with a protecting film. More preferably, it is coated at 2/5-3/5. A single layer plating film of alloys of, for example, Ni and/or Co, Ni-Fe, and/or Co and P and/or B or a conventional plating layer film is used for the protective film. For example, the lower part 22 of a mold base body 20 is cut off to required thickness by machining or the like, and a protecting film 24 is provided on that part. The interface 26 between the body 20 and the film 24 is so processed as not to leave any level difference. These make mold production and repair advantageous. |
