Abstract
Precision forging is a rather new special hot forming technology with a high economic potential. The lifetime of a forging tool is one of the most decisive factors during the economical evaluation of a forging and is therefore the subject of intensive investigation and research work. This paper shows results obtained in experimental work and theoretical analysis for the determination of tool wear. Observations have shown that the temperature of the raw material is of major importance for tool wear because of damaging effects on crystalline structure and in consequence mechanical properties of boundary layers of the forging tool. The example of temperature calculation which is strongly connected with heat exchange inside the tribological system explains the complex problems of the theoretical analysis. Additionally the heat transfer itself influences the geometry of the finished forged part, which is in the industrial case of major importance. The heat transfer during the different manufacturing stages has been analysed using the finite element method, which has been further developed to automatically determine the heat-transfer coefficient. Finally, a new method to calculate wear amounts at critical areas of forging tools is presented.