METHOD FOR PRODUCTION OF PLATINUM GROUP-BASED ALLOY

摘要

PROBLEM TO BE SOLVED: To provide a method capable of massively producing the robust cast ingot of a platinum group-based alloy.SOLUTION: A production process of a cast ingot in a continuous casting system includes: using a plasma arc melting furnace forming a plasma arc column between an electrode torch set on an upper part in a vacuum chamber, and a water-cooled copper crucible of a lower part in a chamber having a cavity of cross section S1; inserting and melting the raw material rod end part comprising a platinum group-based alloy in the plasma arc column, dropping on the substrate in the crucible to form a molten pool; and coagulating the bottom part of the molten pool by pulling down the substrate while holding the liquid level of the molten pool constant. The method for production of the platinum group-based alloy is characterized in that the horizontal cross section area S (mm) and the length L (mm) satisfy the following relation: S1≥S>500,L>4√(S/π); a chamber internal pressure at melting is 0.8 atm or higher; and a pull-down speed is 10 mm/min or lower.SELECTED DRAWING: Figure 2