Tension levelling allows to have much better flatness than roll levelling. It is based in combining high tension of the strip with bending through rolls. The obtained plastification is, therefore, more complete and trapped stresses are less. A tension levelling line is a complex line as the continuous process needs big accumulators and for creating the levelling tension advanced bridles are required.
FAGOR has recently installed for an important Chinese Steel Maker to supply a complete tension levelling line. This new line process stainless steel (series 300/400) in widths up to 1350 mm and thickness range from 0.2 to 3 mm. The estimated production is 200,000 Tons per year. The tensile strength of the material is 800 Mpa and the coils can weigh 28 Tons. The maximum top speed is 250 m/min. The achieved flatness will be better than 3 I-u . The line includes the tension leveler with quick change of rolls, two big vertical loopers, a welding unit to joint the end of one coil with the beginning of the next one in order to have a continuous process, edge trimming unit, fill applicator and the bog bridles that create the main tension.