Abstract: A method of refining molten metal includes the steps of reduced-pressure-refining molten metal in a heated vessel, adding slag-forming agents into the refined molten metal while keeping the molten metal in the vessel, or after pouring the molten metal into another vessel, re-refining the molten metal by heating the molten metal with inert-gas plasma and while stirring the molten metal as occasion demands. Preferably, the refining apparatus includes two adjacent chambers, each chamber isolated from the surrounding atmosphere. The chambers can be connected with, or separated from, each other and each chamber is provided with an exhaust device. One of the chambers is provided with an induction heating refining furnace, and the other chamber is provided with inert gas plasma heater. The apparatus also includes a re-refining vessel which is transferable between the two chambers, and a material feeder for feeding slag-forming agents into the re-refining vessel.

Abstract: A steel which consists essentially of 0.25-0.65% of C, up to 2.50% of Si, up to 2.00% of Mn, 10.00-20.00% of Cr, 4.00-13.00% of Co, 1.00-3.00% of Al, up to 0.25% of N and the balance essentially Fe and ordinary impurities and satisfies the relation:Cr equivalent=-40C(%)+6Si (%)-2Mn(%)+Cr(%)-2Co(%)-30N(%)+12Al(%).ltoreq.13%provides a metal mold which need not be Cr-plated and is suitable of use in molding high-quality glass wares.