APPLICATION FOR COLD
APPLICATION FOR COLD ROLLING MILLS / PROCESSING LINES Reversing Cold Mill, Continuous Annealing Line Skin Pass Mill, Finishing Lines APPLICATION FOR COLD ROLLING MILLS / PROCESSING LINES Reversing Cold Mill Continuous Annealing Line Skin Pass Mill Finishing Lines A one-stand reversing cold mill usually consists of three coilers and a mill stand. Two coilers are needed to wind and unwind the running strip, while the third coiler is used to prepare the next strip. The material is rolled to its final thickness in multiple passes. Four-high, six-high and multiple-roll mill stands are used for cold rolling. The more rolls that are used, the greater the possibilities to influence the material, especially regarding strip geometry. Multiple-roll mill stands contain up to 20 rolls of various diameters arranged symmetrically. Using small work rolls, it is possible to process stainless steel that is usually difficult to form. In cold rolling, the reel tension supports the process of thickness reduction. The following measuring systems are used in a reversing cold mill: • one or multi-head strip thickness gauges (strip centreline measurement or with cross profile function) before and after the mill stand • Laser speed gauges for strip thickness and mass flow control before and after the mill stand, integrated in the strip thickness gauges or as stand-alone systems The material hardens during cold rolling and therefore needs to undergo annealing treatment before further processing. Heating the steel in an annealing furnace changes its solidification structure and its surface structure. The process of continuous annealing comprises the steps of strip cleaning, recrystallisation annealing, skin pass rolling and trimming. The following measuring devices are used at continuous annealing furnaces: • strip thickness gauges (only for strip centreline measurement or with cross profile function) at the entry to and exit from the continuous annealing line • strip width gauges at the entry to and exit from the continuous annealing line with hole and edge crack detectors as optional extensions • strip tension measuring devices in all stages of the production process • residual dirt measuring devices (ellipsometry measuring devices) Rerolling of annealed cold strip improves strip flatness and produces a defined surface topography (surface roughness). At the same time, skin pass rolling achieves a defined yield strength needed for subsequent deep drawing processes, e.g. in the production of beverage cans. Skin pass mills have one or two stands. The following measuring systems are used in a skin pass mill: • strip thickness gauges (only for strip centreline measurement or with cross profile function) before and after the skin pass mill • strip thickness gauge as stand-alone device or with integrated laser speed gauge for strip thickness and mass flow control before and after the skin pass mill • shapemeter rolls before and after the last skin pass mill • strip width gauge at the exit from the skin pass mill with hole and edge crack detectors as optional extensions • residual dirt measuring devices with ellipsometry measuring heads at the exit from the skin pass mill • strip tension gauge before and after the stand In the finishing lines (recoiling, inspection system, cutto-length and slitting lines) the strips are inspected and cut to size. The following measuring systems are used for quality control: • strip thickness gauge (strip centreline measurement or with cross profile function) at the entry or exit (depending on the type of equipment) • strip width gauges at the entry or exit (depending on the type of equipment) with hole and edge crack detectors as optional extensions • strip tension gauge • Shapemeter rolls before the coiler and decoiler • strip tension measuring system before and after the stand. 10 11
