The pressure of the upper roller when pre-bending the plate is normal several times of the sickness of the plate. At present, common approach is to increase the upper roller diameter to reduce the roll deflection or use the drum-roll to eliminate the deformation when rolling. But if for the product diameter is less than the upper roll diameter, can only reduce roll diameter to meet manufacturing requirements, so it will increase deflections, causing heating coil deformity. Our plate rolling machine for small diameter pipe is due to this problem, we increased the lifting pressure rollers on the top roller, it will increase the upper stiffness, eliminate roll of deflection. Upgrade the lifting pressure rollers when rolling, so making the whole round.
