Production method for reducing grain boundary oxidation of hot continuous rolling 65Mn strip steel

Abstract

The invention relates to a production method for reducing grain boundary oxidation of hot continuous rolling 65Mn strip steel. The production method comprises the following steps: smelting 65Mn steel, wherein the steel comprises less than or equal to 0.02% of P and less than or equal to 0.01% of S; selecting covering slag CaO and SiO2 in a ratio of 0.1-1.0 for continuous casting, wherein the thickness of a crystallizer liquid slag layer is not less than 10 mm; controlling the superheat degree range of molten steel to be 15-25 DEG C; performing off-line heat preservation pit or centralized stacking and placing treatment on a continuous casting plate blank, wherein the time is not more than 8 hours, and the furnace entering temperature is not less than 400 DEG C; adopting a weak oxidizing or reducing atmosphere for a heating furnace, and controlling the heating temperature of each section; controlling the rough rolling temperature to be 1030-1060 DEG C, controlling the finish rolling temperature to be 840-900 DEG C, and controlling the coiling temperature to be not more than 730 DEG C, wherein steel waiting or swing cooling is not allowed in the process of carrying the rolled plate blank; and performing laminar cooling in a front cooling mode, and performing side spraying and blowing to avoid water on the surface of the strip steel. According to the production method, the probability of grain boundary oxidation defects in the production process is greatly reduced, the severity degree of grain boundary oxidation is reduced, the quality level of the produced 65Mn strip steel is improved, and the machining performance requirements of users are met.

Description

technical field [0001] The invention relates to the field of metallurgical hot-rolled strip steel, in particular to a production method for reducing grain boundary oxidation of hot-rolled 65Mn strip steel. Background technique [0002] 65Mn steel belongs to high-carbon cutting tool steel, which can be produced by conventional hot rolling and continuous rolling mills. The products are widely used in downstream saw blades, springs, vehicle parts and other industries. During subsequent use, processing fractures often occur, causing users to complain about quality. Metallographic testing found that the grain boundary oxidation cracks on the surface of strip steel raw materials are one of the main reasons for subsequent processing cracking or fatigue failure. Grain boundary oxidation is an oxidation process that occurs preferentially along the metal grain boundary in a high-temperature environment. Oxide formation along the grain boundary destroys the continuity of the material, ...

AI Technical Summary

Problems solved by technology

[0005] The technical problem to be solved by the present invention is to provide a production method for reducing grain boundary oxidation of hot continuous rolling 65Mn steel strip, and to solve the problem of producing 65Mn steel strip in hot continuous rolling line. Reduce grain boundary oxidation defects on strip surface

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