Targeted die temperature control by integrating heat pipes in hot forging tools

• Applicant: Professor Dr.-Ing. Bernd-Arno Behrens
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: from 2010 to 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 189451423

The die temperature influences wear behaviour of hot forging dies. Therefore, combined cooling lubricants are usually applied to the tools in order to prevent wear. Cooling lubricants must always meet the two requirements of cooling and lubrication. Within this project the separation of these two functions and the particular performance of the cooling function are investigated. As an alternative approach to removing heat from a forging die, the use of heat pipes is investigated for the first time. Within the first period of this project, the efficiency of heat pipes under circumstances similar to forging operations was investigated. Subsequently, conventional hot forging dies were equipped with a heat pipe system and used in serial forging tests. Heat pipe cooling lead to a reduction of the die temperature and as a consequence also to a considerable reduction of wear. The basic applicability of heat pipe cooling in hot forging tools was thus proven.The aim of the second period is the investigation concerning to what extent the effectiveness of the heat pipe cooling can be increased by improving the thermal coupling between heat pipes and forging dies. For this purpose, plastic deformation and solder techniques shall improve the thermic coupling. Serial forging tests are performed and the effectiveness and durability of the thermal coupling between heat pipes and forging dies are investigated under cyclically high thermomechanical stress. Their potential for heat transfer and wear reduction are evaluated. For a conclusive evaluation, the tool wear is examined by destructive and non-destructive methods.After the conclusion of all examinations, knowledge about the influence of the thermal coupling between heat pipes and forging dies on the heat flow will be available and applied to the wear development.

• DFG Programme: Research Grants