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

Abstract

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.

Description

technical field [0001] The invention relates to the technical field of roll surface treatment, in particular to a method for overlaying and rebuilding Cr4 of a large hot-rolled backup roll and a roll repairing method. Background technique [0002] my country is a big country in steel production and consumption, among which rolled products account for about 85%-90%. The roll is a tool for plastically deforming (rolled material) metal, and is a key spare part for steel rolling enterprises. It is expensive, and its performance directly affects the product quality and production cost of the enterprise. With the prolongation of using time, wear and tear are unavoidable. The wear changes the initial roll shape of the roll and deteriorates the quality of the roll surface, which brings great difficulties to the quality control of the product. [0003] With the demand of the domestic hot-rolled strip steel market, the hot-rolled strip steel has developed from narrow strip steel to ...

AI Technical Summary

Problems solved by technology

[0004] Due to factors such as heavy roll weight, large roll diameter, long roll surface, and thick wear-resistant layer, it is difficult to repair large-scale hot-rolled backup roll Cr4 by traditional surfacing welding. A phase change occurs, leading to cracking

Therefore, the deficiencies of the existing roll surfacing and repairing process make the repaired rolls have poor mechanical properties and limit the service life of the rolls. A large number of scrapped rolls, especially large rolls, are piled up in the rolling mill for a long time, causing a lot of waste. increased production costs

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