Patent ID: 9174257
Filing Date: 2015-11-03
Classification: B21D

Abstract:
1. A method for stretch-bend leveling metal strip with a stretch-bend leveler with at least two straightening rollers in a row one after the other in a strip-travel direction, the method comprising the steps of: spacing the straightening rollers in the travel direction by at least 30% of a width of the strip, bending the strip under tensile stress below the elastic limit bidirectionally around the straightening rollers such that the strip undergoes plastic stretching, providing upstream of each of the straightening rollers movable relative to the strip a respective deflection roller having a larger diameter than the respective straightening roller provided immediately downstream, engaging the straightening rollers at least generally transversely of the travel direction with the strip such that the strip wraps around each of the straightening rollers over a predetermined wrap angle and with a predetermined immersion depth and that a free strip length of the strip extends straight between contact of the strip with each of the deflection rollers and contact with the respective straightening rollers, and positioning the straightening rollers for the variation of the immersion depth relative to the respective deflection rollers such that the free strip length does not exceed a predetermined maximum value equal to 8% of the strip width to prevent formation of longitudinal waviness of the strip.