Patent ID: 8695392

Claim:
A six-high rolling mill including upper and lower work rolls as a pair for rolling a metal strip, upper and lower intermediate rolls as a pair for supporting the work rolls, and upper and lower back-up rolls as a pair for supporting the paired upper and lower intermediate rolls, with only the intermediate rolls having a roll shoulder whose roll diameter decreases, the six-high rolling mill having no supporting rolls inside and extending beyond both sides of a rollable strip width of the work rolls, wherein the work rolls comprise a material having a high modulus of longitudinal elasticity, and a minimum roll diameter of the work rolls is between a minimum diameter upper limit Dmax 1 and a minimum diameter lower limit Dmin 1 , wherein the minimum diameter upper limit Dmax 1 =D 4 max×B/K (1/4) , where D 4 max is about 380 mm, corresponding to a minimum diameter upper limit of a work roll with conventional strip width of about 1,300 mm, B is a strip width (mm) of the work rolls/1,300 mm, and K is the ratio for modulus of longitudinal elasticity of the high longitudinal modulus material to a material with conventional modulus of about 21,000 kg/mm 2 , and the minimum diameter lower limit Dmin 1 =D 4 min×B/K (1/4) , where D 4 min is about 180 mm, corresponding to a minimum diameter lower limit of a work roll with conventional strip width of about 1,300 mm.