EUROPEAN STEEL TECHNOLOGY AND APPLICATION DAYS 2017 - ESTAD 2017

The changed chemical composition of modern advanced high-strength steel (AHSS) grades has certain influences on the pickling process. Especially the higher contents of silicon and manganese have a critical impact on the process, which leads to problems in conventional pickling lines. The most significant challenges are sludge occurrence, varying pickling times, changed visual appearance, required high surface qualities, and weld ability. Based on the turbulence pickling technology SMS has developed some features and modifications, which allow an efficient production of these new materials. The higher sludge occurrence is based on the higher silicon content. Due to the huge experience with electrical steels with high silicon contents, appropriate solutions are available. Sludge removal is possible with the proven two tank system and a sedimentation system before regeneration. Furthermore, the high turbulence flow in the pickling section prevents sedimentations. The Eco-pickling and production model controls the process, which pickling parameters can be changed quickly to apply varying pickling times when necessary. In addition, the turbulence pickling system ensures a homogeneous surface quality and removes impurities from the surface. SMS offers the X-Pro® laser welder for a safe and reliable connection of the coils in the entry section, which is perfectly suitable to weld grades with high alloying/silicon contents. The integrated, patented inductive weld seam heat treatment for most difficult weldings is an essential feature of this machine. The automatic weld parameter calculation based on material cast analysis as well as the automatic measurement and adjustment of weld gap and weld position are supporting the production of these materials. Another highlight is the short cycle-time of less than 60 seconds. This paper describes the influences of the changed chemical composition of modern steel grades on the pickling process and gives an overview about the technical solutions.