LUBRICATION OF MAGNESIUM WORKPIECES FOR HOT FORMING

摘要

The elevated temperature forming of magnesium based alloy workpieces by stretching, drawing, bending (or the like) a surface of the heated workpiece over the forming surface of a forming tool is improved by forming an integral adherent layer of magnesium hydroxide on the tool- contacted surface(s) of the magnesium alloy workpiece. The magnesium hydroxide layer may be formed by treating the surface(s) of the sheet with an aqueous salt solution (e.g., sodium chloride) at a temperature and for a time to form a protective layer of desired thickness (e.g., up to about thirty micrometers). If desired, an additional layer of forming lubricant, such as a film comprising boron nitride, may be applied to the magnesium hydroxide layer.