Remanufacture of Hot Forging Dies By LMD-p Using a Cobalt Based Hard-Facing Alloy

Additive Manufacturing (AM) technologies are providing exciting opportunities for repair and remanufacture of industrial components. Laser Metal Deposition with powder (LMD-p) is an ideal candidate process for selective remanufacture of high value tools and dies exhibiting wear, particularly on complex geometries found in hot forging applications. When used in combination with a multi-axis CNC machining centre and a suitable metal powder metallurgy, LMD-p can produce hybrid (additive/subtractive) remanufacturing operations which exceed the original wear characteristics of production die sets. DigiTool, a consortium funded project by Innovate UK, consisting of the Advanced Forming Research Centre (AFRC) and five industrial partners, developed a remanufacturing process for complex closed die tooling geometry. After careful consideration of commercially available metal powders in the range 40 to 120 µm for use with LMD‑p, MetcoClad 21, a cobalt based hard-facing alloy, was selected as the metal powder repair medium due to its superior sliding wear resistance, galling, and machinability. Experimental trials determined the optimum LMD-p process parameters and worn H13 tool steel hot forging dies were successfully remanufactured along the complex flash land areas and pocket features in the cavity. The selective die repairs were subsequently verified in a production environment at the customer site, resulting in die life increase of 108% whilst maintaining all dimensional and customer quality standards. The die life increase has allowed the customer to reduce the piece-part cost and win the business back from a competitor.