Targeted influencing of the material flow during pipe drawing by localised heating

• Applicant: Professor Dr.-Ing. Johannes Buhl
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: since 2025
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 556119258

The aim is to control the material flow during tube drawing by defined local heating and thus to specify the eccentricity as a process control variable. The pipe is heated locally at a suitable point in order to facilitate plastic deformation compared to the unheated areas, so that increased flow in the circumferential direction takes place in this area and ultimately the existing thickening - and thus the eccentricity - is reduced more significantly - or, if necessary, increased - than is the case under standard conditions. The special requirement in this project is to adjust the local heating via the controlled energy input in such a way that neither underheating nor overheating or even undesired structural changes - and thus local property changes - occur. The process window includes the energy input, the drawing speed and the material-specific properties. To determine the optimum combination of parameters, the effects of localised heating during drawing on the tube geometry, the resulting microstructure, the development of strength, yield strength, ductility and hardness must be investigated for the respective materials. With the help of FEM simulation, the spatial and temporal temperature profile of the drawing process is to be calculated in advance, taking into account the local energy input, and the criteria for a stable and process-reliable design are to be determined. Numerical optimisations provide information on the control of the heating zones, the heating depths and the maximum temperature (temperature-time regime). This makes it possible to determine an optimum generator output (specification of inductor frequency and current) for the measured variable ‘eccentricity’ and to integrate it into the raw drawing plant in the form of a model-based control system.

• DFG Programme: Research Grants
• Major Instrumentation: Induktionsheizung
• Instrumentation Group: 8420 Spezielle Oefen (Induktions-, Lichtbogenheizung, Vakuumöfen)