Extension of the process understanding and the application fields for longitudinal seam high frequency welding of tubes by process mapping using model process and finite element simulation

Funding: DFG

Duration: 03/13-03/16

To date, there is no systematic investigation of the influencing factors weld gap formation and microstructure with regard to the formation of weld defects in high-frequency welding. Furthermore, the defect formation mechanisms are not uniformly represented in the literature at the present time. Within the scope of the project, the systematic investigation of the defect formation mechanisms during high-frequency welding is carried out by experimental analysis of a semi-continuous model process, which reproduces the longitudinal seam welding of pipes on a laboratory scale and ensures comprehensive process observation. By means of suitable parameter settings and the possibility of process shielding by means of shielding gas, the above-mentioned influencing factors and thus their process influences can be considered separately. Based on the knowledge gained from the model process, a finite element simulation model is being developed which can depict longitudinal seam tube welding. The model should be able to calculate parameter fields for any steel material by specifying microstructure (electrical conductivity, permeability, thermal conductivity, etc.) and chemical material composition (molten bath surface tension, molten bath viscosity). On the one hand, this makes it possible for the first time to determine the effects of alloying element fluctuations for a given steel grade. On the other hand, the weldability of previously unprocessed steel grades can be determined without the need for expensive welding tests in order to specifically expand the range of materials that can be processed.