A method for flattening steel strip by cold rolling wherein the strip is passed through at least two cold rolling mill stands each having work rolls. A first mill stand has work rolls having local rigidity K significantly different from a second milled stand. The local rigidity K is calculated in Kgf/mm/mm in accordance with an equation. A six high mill comprises a pair of driven backup rolls disposed on the entry side, a pair of horizontal support rolls disposed on the exit side, and a pair of small diameter work rolls having an entry side face and an exit side face. The work rolls are disposed between the backup rolls and the support rolls, wherein during operation the entry side face of the work rolls engages the backup rolls and the exit side face of the work rolls engages the support rolls.