Patent ID: 9737931
Date: 2017-08-22
CPC Classifications: B22D,C22C,C22F

Claim:
1. A method for producing a platinum group-based alloy, the method comprising a molten ingot production step of a continuous casting system using a plasma arc melting furnace configured to form a plasma arc column between an electrode torch which is arranged in an upper part of a vacuum chamber and a water cooled copper crucible which is arranged in a lower part of the chamber and has a cavity having a sectional area S 1 , the molten ingot production step comprising: inserting and melting an end part of a raw material bar comprising a platinum group-based alloy in the plasma arc column to cause the raw material bar to fall in drops on a base material in the water cooled copper crucible, to thereby form a molten pool; and solidifying a bottom part of the molten pool while maintaining a constant liquid level height of the molten pool by pulling down the base material, the molten ingot having a horizontal sectional area S and a length L satisfying the following relationship: an internal pressure of the chamber during melting being 0.8 atm or more, a pulling down speed of the base material being 10 mm/min or less.