Numerical models to improve HFI welding process parameters

Improvement of existing welding technology requires numerical models to better understand the underlying physical interactions and optimise process parameters. In order to enhance our understanding of High Frequency Induction Welding, OCAS developed numerical models taking into account electromagnetic, thermal and mechanical effects.

High-Frequency Induction (HFI) welding is a widely used technology to produce tubes from strip. In this continuous process, the strip is formed into a cylindrical shape by rolls and passed through an induction coil to heat up the edges of the strip. Finally, the edges are squeezed together and welded. As can be expected, the quality of weld strongly depends on the process parameters, such as power, frequency, squeezing force, etc. However, there exist no tools to obtain optimal process parameters, and these are normally determined through costly trial-and-error runs on an industrial line.

OCAS has developed numerical models with coupled electromagnetic and thermal physics to predict the temperature profile of the strip as it passes through the induction welder. Further, a mechanical model was also developed to predict the squeeze-out of oxides when the edges of the strip are pressed together.

The model allows us to provide recommendations to our customers for optimisation of the process parameters and implementation of a sophisticated forging control to improve toughness of HFI welded pipes for energy applications.

2D-model

Cross-section of the edges just before squeeze-out, with colors indicated the predicted temperature throughout the thickness Cross-section of the edges at the start of the squeeze-out. Cross-section of the edges after squeeze-out.

 

3D-model

Predicted temperature, arrows indicate velocity of tube

 

 

“Our models have the potential to minimise the number of expensive trials that are required to optimise process parameters, improve the weld quality in existing products and speed-up the introduction of new pipe materials.”

Jan Rens, Senior Research Engineer Applications & Solutions department, OCAS
Özlem Esma Ayas Güngör, Senior Research Engineer Welding, Applications & Solutions department, OCAS