Back-up roll device and method for conducting corner deformation on chamfered continuous casting slab

A back-up roll device for conducting corner deformation on a chamfered continuous casting slab, wherein the chamfered continuous casting slab is provided with two to four original chamfered bevels, and each original chamfered bevel has an obtuse angle on a wide face of the continuous casting slab, wherein,

• the back-up roll device comprises back-up rolls with α-angle bevels, movable bearing seats, bearing seat moving rails, bearing seat motion holding mechanisms, and inner arc or outer arc frames of a casting machine;
• the back-up rolls with α-angle bevels are arranged on the inner arc and/or outer arc frames of a horizontal segment of the casting machine, and support surfaces of the back-up rolls with α-angle bevels make contact with and squeeze obtuse angles adjacent to the wide face of the inner or outer arc on the chamfered continuous casting slab, so that each obtuse angle is squeezed into two larger obtuse angles;
• displacement sensors for measuring working positions of the back-up rolls with α-angle bevels are arranged in the holding mechanisms for moving the bearing seats.