Patent ID: 7621201

Claim:
A ferrous metal tool for forming aluminum alloy or other light metal alloy sheet workpieces at forming tool and workpiece temperatures above about 250° C., the tool having a body with a machined portion defining a forming surface for sliding contact engagement with a heated sheet workpiece in deforming the workpiece, the forming surface comprising: a nitrocarburized surface layer at a forming surface to be contacted by the workpiece, the nitrocarburized surface layer being coextensive with the forming surface, the nitrocarburized surface layer initially comprising a compound surface layer with an underlying diffusion layer, the compound surface layer comprising an outer gamma-prime phase and underlying epsilon-phase; and the nitrocarburized epsilon phase material of the compound layer containing embedded particles of low friction material that are infusible at the forming temperature of the forming surface, and at least a majority of the gamma-prime phase layer being removed from the forming surface of the tool prior to embedding of the particles in the epsilon phase material.