February 2024 Volume 6

MAINTENANCE

MATERIALS

Pre-Piercing and Piercing Stages As the process moves to the piercing stages, as shown in Figures 7 and 8, similar behavior between the simulation and industrial trial is observed.

For a clear view of how the steel flows during ring rolling, Figure 10 brings together all the samples from start to finish.

Figure 7: Sample after pre-piercing showing the material flow of the rods from the practical industrial trial (top row) and from the FORGE simulation (bottom row).

Figure 10: Results from the practical industrial test showing material flow through the various stages of the ring rolling process. Visualization Offers Exciting Opportunities Clearly, this simple and elegant approach developed by the Ovako R&D team offers exciting new possibilities to visualize how steel flows during hot-working. For the next stages of the project the investigation will be expanded from ring rolling to visualize other processes such as forging, rolling and tube rolling. For decades, engineers have relied on external checks such as temperature monitoring, dimensional accuracy and surface finish to determine the quality of a hot-worked product. The drawback of these methods is that they do not go inside the workpiece. With this new approach, it will now be possible to develop a deeper understanding of how metal flows internally under hot working. Using this knowledge will provide the foundation for refining processes to deliver the highest product quality. It is also important to note that, because this new visualization method shows such good correlation with FEM simulations, it will help to ensure greater confidence in using FEM for process optimization. Patrik Holm R&D Team - Ovako Email: Patrik.Holm@ovako.com Patrick is based at Ovako’s Hofors Mill in Sweden.

Figure 8: Sample after piercing showing the material flow of the rods from the practical industrial trial (top row) and from the FORGE simulation (bottom row). Final Ring Rolling The final ring rolling stage is illustrated in Figure 9. There is still a strong correlation in the flow pattern as visualized by the FORGE test and demonstrated by the practical industrial test, even at this stage.

Figure 9: The final ring rolling stage still shows a strong correlation between the flow pattern demonstrated by the practical industrial test (top row) and the FORGE simulation (bottom row).

FIA MAGAZINE | FEBRUARY 2024 41