| 摘要 |
PROBLEM TO BE SOLVED: To provide a valve for drinking water capable of being produced in a mass production-scale, of which a machinability is secured to be equivalent to that of a bronze alloy (CAC046) and mechanical properties, especially tensile strength, and castability are improved, despite reduced contents of rare elements being alternative elements for Pb. SOLUTION: The bronze alloy comprises, by mass, 5.0-10.0% Zn, 2.8-5.0% Sn, 0.4-3.0% Bi, a prescribed amount of Se and the balance being Cu and unavoidable impurities. The prescribed amount of Se is determined such that the amount of non-solid solution calculated by the formula: 0.93 Bi (mass%)+2.86Se (mass%) falls within a range whose upper limit is 4.90 (vol%) and that the tensile strength does not fall below 215 N/mm<SP>2</SP>, which is a value derived from the standard value of CAC406, taking the production error into consideration. In the bronze alloy, the Bi content is minimized and the Se content is maximized. The valve for drinking water is molded by using the bronze alloy excellent in tensile properties. COPYRIGHT: (C)2006,JPO&NCIPI
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