GB697993A - Improvements in or relating to the purification and production of articles of magnesium and magnesium alloys - Google Patents

Abstract

A process for treating Mg and Mg-base alloys comprises introducing the molten metal into a container which is rotated at a speed high enough to produce a comparatively sharp separation of undesirable suspended particles, rotating the container until the metal solidifies, the solid metal being stripped from the container and the outer skin containing the particles removed. The container may be of such shape that the solidified metal has projections containing the particles to facilitate machining off unwanted material. The machined casting may then be melted and recast and/or forged, extruded or rolled. The alloy to be treated may contain Zr with or without elements which in molten Mg do not combine with Zr to form compounds insoluble in the Mg. To maintain the Zr content of the Mg the container may also contain an alloying composition capable of introducing Zr into Mg. The treatment may be applied to a Mg base hardener alloy containing Mn or Zr which is then melted with a further quantity of Mg or Mg alloy. The Specification refers specifically to treatment of an alloy of 8 per cent Al, 0.5 per cent Zn, 0.25 per cent Mn, remainder Mg. Specifications 511,137, 649,594 and 652,227 are referred to.