Method for annealing a strip of steel having a variable thickness in length direction

摘要

A method for annealing a strip of steel having a variable thickness in its length direction with at least thicker and thinner sections, wherein the strip has been cold rolled to form the thicker and thinner sections, one thicker and one thinner section having a length of at most a few meter. The annealing is performed by continuous annealing.

主权项

1. A method comprising:
annealing a strip of steel, the strip of steel having a variable thickness in its length direction with at least thicker sections having a length of at most two meters and thinner sections having a length of at most two meters, such that the strip has a repetitive thickness variation, wherein the strip has been cold rolled to form the thicker and thinner sections, wherein the maximum temperature and/or the soaking temperature of the strip of steel during the annealing is kept within a range with a width of 100° C., wherein thicker and thinner sections of the strip of steel are selectively heated to anneal the strip of steel and recrystallize the thinner sections, wherein the selective heating is performed using induction heating at a single constant frequency between 5 and 50 kHz to heat the thicker sections to a selected temperature and a single constant power density, wherein the same frequency and the same power density are simultaneously applied to the thicker and thinner sections, and cooling the annealed strip, the strip to be cut into pieces called tailor rolled blanks, wherein the annealing is performed by continuous annealing.