| 摘要 |
PROBLEM TO BE SOLVED: To provide a zinc-base alloy for metal mold, excellent in molding quality, such as dimensional accuracy, as well as in workability, having strength capable of withstanding injection molding of more than tens of thousands of shots, suitable for manufacture of small-quantity-produced metal molds, free from pinholes, and capable of giving metal molds easy of repair by repair welding, etc., a zinc base alloy block, and their manufacture. SOLUTION: The zinc-base alloy for metal mold has a composition consisting of, by weight, 5-15% Al, 3-6% Cu, 0.01-0.1% Mg, and the balance Zn besides inevitable impurities and also has a structure whereε-phases composed of Zn-Cu solid solutions existing granular state. The zinc-base alloy block for metal mold is composed of the alloy having the above composition and structure and has >=25 kgf/mm<2> tensile strength measured at 25 deg.C and also has >=100 HB surface hardness. The zinc-base alloy for metal mold or the zinc-base alloy block for metal mold can be manufactured by subjecting a molten metal of the above zinc-base alloy to unidirectional solidification.
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