Influence of design and process parameters on service life of nut hot forging die

A nut hot forging die was investigated in order to increase its life time. In a first step forging process simulation shows that die surface temperature reaches 450 °C and that mechanical loads on the die are closely related to the accuracy of the initial billet length. In a second step die thermo-mechanical simulation was used to optimize the design: geometrical aspect as well as shrink fitting were investigated. Life time increase was estimated in using the Manson universal slope relation. This increase was confirmed from the practical results.