HEAT TREATMENT OF BELTLIKE ELECTRICAL CONTACT MATERIAL

摘要

PURPOSE:To prevent the deterioration of an electrical contact material contg. a metallic element with high vapor pressure in the contact performance due to the evaporation of the element and the deposition on the material by using a vertical type heat treating furnace when the material is heat treated. CONSTITUTION:An electrical contact material made of Ag alloy contg. a metallic element such as Cd or Zn with high vapor pressure or a beltlike composite electrical contact material 1 formed by joining a base metal made of Cu alloy to the beltlike Ag alloy material is heat treated by being vertically moved in a vertical type electric furnace 8 for heat treatment provided with an upper heating zone 4' and lower cooling zone 5'. Even if the contained metal such as Cd or Zn with high vapor pressure is evaporated in the zone 4', it is exhausted from the upper opening 4'a of the zone 4' and is not deposited on the contact material 1. Accordingly, the deterioration of the contact material in the contact performance such as a reduction in the electrical conductivity or an increase in the contact resistance is prevented.