Lehrstuhl für Fertigungstechnologie, Universität Erlangen-Nürnberg

Material adapted design of cold forging tools exemplified by powder metallurgi-cal tool steels and ceramics



Datum: 13.12.2011


Author


Reporter

  • Prof. Dr.-Ing. habil. M. Merklein
  • Prof. Dr.-Ing. A. E. Tekkaya

>Since every single characteristic of the tool material in cold forging is heavily dependent on the process, meaning that there is no one optimum combination of mechanical, chemical and thermal properties that is  suitable for all possible cold forging applications, an adaptation of the tool design by means of proper prestressing systems,  numerical simulation of the production process, etc. becomes crucial in order to get the most out of the advantages of a tool material. To emphasize the importance of this material adapted design of cold forging tools two processes, utilizing powder metallurgical steel and industrial ceramic (Si3N4) as tool materials, have been investigated within this work. Carbide structure, hardness, compressive strength and therefore achievable level of prestress have been determined as primary parameters of influence in case of PM steels. For silicon nitride ceramic a complete elimination of tensile strains taking into consideration the thermal interactions between ceramic insert and steel prestress rings is of great importance for a fatigue free application of this material in cold forging processes.