Reducing adhesive wear in dry deep drawing of high-alloy steels by using MMC tool

Abstract

Sheet metal forming normally requires the application of lubricants to protect the tool and the sheet against wear. In the case of nonlubricated sheet metal forming, cleaning processes would not be necessary anymore and the process chain could be optimized regarding ecological and economical aspects. However, forming without lubrication leads to an intensive contact between the tool and the sheet. Thus, higher wear occurs and process reliability cannot be ensured for industrial mass production. For dry metal forming of high-alloy steels, a new tool concept must be developed to withstand the higher loads. In this work, a laser-generated tool surface with a supporting plateau of hard particles is presented. Spherical fused tungsten carbides were injected into the surface by laser melt injection. The metallic matrix of the composite was rejected by applying laser ablation. In consequence, the hard particles stood out of the matrix and were in direct contact with the sheet material. Dry and lubricated forming experiments were carried out by strip drawing with bending and deep drawing of cups. Within this work, the feasibility of dry metal forming of high-alloy steel could be demonstrated by applying the MMC surface whereby adhesive wear could be reduced.