Conventional Cast Slab Centerline Segregation Rating Benchmark Efforts at ArcelorMittal

摘要

Slab centerline segregation rating has been heavily relying on Mannesmann Demag rating system within ArcelorMittal steel plants. However, at local plant level, the interpretation, standardization, classification, sampling and surface machining procedure, etching methods, and image processing are very different from plant to plant and even from technician to technician within the same lab. In an effort to unify the rating method and system across all ArcelorMittal plants, a benchmark work was carried out aiming to understand how much difference can be seen in rating results among all participating labs and personnel. This work confirms that huge difference exists across all plants under current conditions. It points out that one of the best ways to unify the system is to use computer-aid image processing with automatic rating program. This paper will review the benchmark process, results and some centerline chemistry analysis efforts. The real difficulties, however, were to verify the link between rating results and final product quality as current steel cleanliness levels far beyond the 1980's when centerline quality rating system was introduced.