Ceramic-Metal Composites in Forging Applications

Additional to high mechanical force, forming relevant surface areas of forging dies underlie thermal and chemical loads. Basically, a strength loss in the tools surface is held responsible for initiating wear, which represents the major cause of failure. The loss is caused by thermal fatigue. Occurring temperature peaks during the contact period can exceed the annealing temperature of the tool material, resulting in a de-hardening. Abrasion within these critical areas can be decreased by inserting Si(3)N(4) inlays, because of the outstanding high temperature properties of the ceramic material, especially due to the high hardness. By means of active brazing, a composite tool is manufactured, which minimizes wear in precision forging application. This paper deals with the development of a Si(3)N(4)/hot work steel composite precision forging die for the production of small model gears. The joint is realized by titanium containing copper and silver based active braze alloys.