Thin Hot Strip - Two Approaches to Pickling and Galvanizing

摘要

Production of thin hot strip with gauges between 0.8mm and 2.0 mm was made possible with the introduction of Compact Strip Production (CSP? by SMS Siemag) and Endless Strip Production (ESP? by VAI, Arvedi). These technologies substantially cut the related costs compared to conventional casting and rolling processes. They are described in detail in many articles elsewhere [1, 2, 3, 4, 5, 6]. Also most steel grades, including Advanced High Strength Steel (AHSS) can be produced by these methods. Up to now mostly cold strips were galvanized although there have been some lines for galvanizing of hot strip in operation for quite some time (7, 8). For these conventional applications the strip must be annealed in order to recrystallize the material after the cold reduction step before the coating can be applied. The state of the art process is continuous galvanizing line (CGL), where a continuous annealing furnace is combined with hot dip galvanizing process. Different annealing technologies can be applied in order to realize the annealing temperatures in the range of 650 to 850 C. By the introduction of thin hot strip processing lines the need arises to find economical solutions for the pickling and subsequent galvanizing of these products. It is attractive to couple the pickling and the galvanizing process in one line the so called PGL, a combination of pickling with hot dip galvanizing. For some products it may also be interesting to combine pickling with electrolytic galvanizing (P-EGL).