Method for removing streak defects on hot rolled steel plate surface

Abstract

The invention discloses a method for removing streak defects on a hot rolled steel plate surface and relates to a steel plate surface treatment method. The method comprises the following process: heating plate blank to 1200-1250 DEG C, and then, descaling by high pressure water at a descaling temperature of 1100-1200 DEG C, wherein water pressure required for descaling is at least 16 MPa; carrying out rough rolling on a descaled steel plate at a rough rolling temperature of 1100-1200 DEG C; carrying out finish rolling on the steel plate subjected to rough rolling, wherein a final rolling temperature of the finish rolling is 900-990 DEG C, and the speed of a roller way is 1.3-1.8m / s; after the finish rolling is ended, carrying out water-cooling by adopting a laminar cooling mode, and adopting sectional type cooling, wherein a water ratio is 2.2-2.6, the cooling water consumption is 150-250m<3> / h, and a red temperature of the cooled steel plate is 670-750 DEG C; and cooling the water-cooled steel plate in air at a cold bed. According to the method, oxide iron scale on the surface of the steel plate is easy to remove in a follow-up shot blasting process, thereby removing the streak defects on the steel plate surface subjected to shot blasting.

Description

technical field [0001] The invention relates to a steel plate surface treatment method, in particular to a method for eliminating mottled defects on the surface of a hot-rolled steel plate. Background technique [0002] The hot-rolled steel plate will produce a layer of oxide scale on the surface of the steel plate during the rolling process. Under different hot rolling conditions, the structure and thickness of the obtained iron oxide scale are changed. Hot-rolled sheets are playing an increasingly important role in the national economy, but the main concern is performance quality and dimensional accuracy. Surface quality has become a common problem in the industry that restricts the overall quality of hot-rolled sheets in my country. Due to the long-term lack of attention to the surface quality of hot-rolled steel products, these products often have problems such as red rust, pits and pits due to improper control of the surface iron sheet, causing many quality objections ...

AI Technical Summary

Problems solved by technology

Chinese Patent Application No. 200710010183.5 "Medium and Thin Slab Continuous Casting and Rolling Strip Steel Surface Scale Control Method" provides the scale for medium and thin slab hot-rolled strip steel including composition design, descaling process, rolling and cooling process The control method is mainly aimed at the short-process production line of medium and thin slabs, and the main solution is how to remove the red rust on the surface. It does not mention how to eliminate the color difference defects after shot blasting on the surface of the steel plate

Chinese Patent Application No. 201010010116.5 "A Method for Detecting Scale Structure of Hot-Rolled Strip Steel by Chemical Corrosion" provides a chemical detection method for detecting the scale structure of hot-rolled strip steel, which is useful for controlling the structure and thickness of scale on the surface of steel plates wait did not introduce

Chinese Patent Application No. 201010189410.7 "Flexible Control Method of Scale on Hot-rolled Strip Surface" provides a method for controlling the structure and adhesion of scale on the surface of steel strip in a hot-rolled production line. Different processing characteristics are shown in the deep processing process. How to require different structure of iron oxide scale according to the deep processing process characteristics of downstream production enterprises (whether there is an oiling process) does not involve how to eliminate the surface defects of the steel plate

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