Reduction of surface defects on hot rolled products

Important results from the project

The project will develop a complementary method, based on advanced camera technology, to the generally accepted manual control. In addition to developing hardware to perform measurements in harsh environments, advanced microscopy and surface analysis techniques will be used to characterize different types of surface defects and investigate the underlying mechanisms for their formation. All in all, this should facilitate the tracking of the occurrence of surface defects. The goal is to develop a tool that can reduce the occurrence of surface defects on hot-rolled products.

Expected long term effects

The project has succeeded in carrying out measurements in tough industrial environments with an in-house developed camera system. Resolution and quality of images have been shown to be good enough for detection of small surface in collected data. The system has also been able to measure materials that move quickly in the manufacturing process. In some cases, it has not been possible to get direct feed back what an observed surface defect looks like in reality as system was located some distance from the rolling mill´s own control system. All in-depth analysis has been performed offline.

Approach and implementation

During the project, field measurements were carried out in five different process lines. The measurement locations were at Erasteel Kloster, Ovako, Kanthal, SMT/Alleima and Outokumpu Fagersta Stainless respectively. All measurements were performed during production and thus under "real" conditions, which was one of the goals of the project. The installation of the equipment was mainly carried out during planned production stops in order to minimize any impact on production. Analysis of data was performed manually and offline after data was collected at each plant trial.