Protection from Coil Ruptures in Rolling Mills By Means of Automatic Optical Control of the Surface Quality
Rising production speeds increase the risk of coil breaks in rolling mills due to both visible and hidden material defects. A typical number of seven coil breaks per months is recorded in coupled pickling and tandem lines as well as in non-coupled tandem lines. Approximately half of these breaks are due to visible material defects on the surface. Apart from material losses, coil breaks may cause loss of production of over one hour. This essay presents the results and advantages of a defect warning system to prevent coil breaks in tandem lines. The prerequisite for this is an inspection system installed in the upstream pickling line. The basis for this are detection, classification as well as access to information «relevant» for quality decisions, which is enabled by innovative filter stages. This information may be used for an anticipatory analysis of potential production failures. It leads to a re-definition of the inspection performance as the number of correct quality decisions based on data quality. Methods on which inspection systems are based in order to meet such requirements are introduced.