| 摘要 |
A method of producing a vacuum circuit breaker, the breaker contacts of which are made of a cast alloy which contains copper or a copper alloy as its main component and, as the sub-component, a metal having a lower melting point and a higher vapor pressure than the main component and having a solubility limit to the main component at room temperature, e.g. lead, bismuth or an alloy of lead and bismuth, the sub-component being contained in excess of said solubility limit. The cast alloy is heated at a temperature not lower than 800 DEG C. but not so high as to cause a melting of the cast alloy, in a vacuum atmosphere which ranges in a pressure between 10-4 and 10-6 Torr, before the alloy is mounted as the breaker contacts in the vacuum circuit breaker. A plastic working may be imparted to the cast alloy before the mounting, by, for example, forging. Further, a second heat treatment may be effected on the cast alloy to which the plastic working has been imparted, under the same condition as the first heating. The heating is effective in promoting the spheroidization of the sub-component, and contributes to the prevention of exudation of sub-component to the surface of the breaker contact. |
