| 摘要 |
PURPOSE:To form a hardened alloy layer and to obtain prescribed hardness by coating preliminarily metallic powder on the surface of a casting mold corresponding to the part requiring hardness of a casting and casting a molten metal into the mold so that the molten metal is brought into contact with the metallic powder. CONSTITUTION:Setting of the kind, grain size, combination, etc. of metallic powder is important to obtain a desired hardened alloy layer. 1 or >=2 kinds among Mn, Cu, Ni and Sn or iron alloy thereof having <=100 mesh grain size are selected for the metallic powder to be coated for the above-mentioned purpose. The contents of Mg, S and O in the molten metal are kept respectively by weight at <=0.03%, 0.005% and 10ppm. |
