Surfacing reconstructed layer of large hot-rolled supporting roll Cr4 and method for repairing roll

The invention relates to a surfacing reconstructed layer of a large hot-rolled supporting roll Cr4 and a method for repairing a roll. The surfacing reconstructed layer is prepared by surfacing prepared flux-cored wires of a bottoming layer, a transitional layer and a working layer on the surface of a base body of the roll layer by layer, and the bottoming layer, the transitional layer and the working layer are sequentially arranged in a surfacing manner from the surface of the base body to the outside. The method comprises the following specific steps: roll preparation, preparation of the flux-cored wires, roll preheating, preparation before welding, sequential surfacing of the bottoming layer, the transitional layer and the working layer, intermediate heat treatment, final heat treatment, machining, examining and shipment. The method is suitable for repairing large and ultra-large hot-rolled supporting rolls, and the service lives of the repaired rolls are close to and even equal to the service lives of new rolls. The cost-performance ratio of the reconstructed layer is high, base body bonding strength, high-temperature resistance, wear resistance and corrosion resistance are excellent, and the using performance of the roll can be improved. The surfacing reconstructed layer of the large hot-rolled supporting roll Cr4 and the method for repairing the roll conform to a green manufacturing technology of national circular economy and a stainable development strategy, and have a wide application prospect and an economic benefit.