Additional to high mechanical force, forming relevant surface areas of forging dies underlie thermal and chemical loads. Basically, a strength loss in the tool’s edge layer is held responsible for instating wear, which represents the major cause of failure. The loss is caused by thermal fatigue. Occurring temperature peaks during the force contact period can exceed the annealing temperature of the tool material, generating a de-hardening. Resulting abrasion within these endangered areas can be decreased by inserting Si3N4 inlays, because of the outstanding high temperature material properties of ceramics.
By means of active brazing, a composite is manufactured, which minimizes wear in precision forging. In addition to the mere joining task, there are further demands on the joining process, like an integrated hardening and tempering within the temperature cycle.
This paper deals with the development of a Si3N4/hot-work steel composite die for precision forging of small model gears. The joint is realized by titanium containing copper and silver based active braze alloys. Furthermore an overview of the application behavior is given.