A Production Method for Controlling Straight Crack Defects on the Surface of Medium and Heavy Plates

Abstract

The invention belongs to the field of continuous casting and rolling of steel, in particular to a production method for controlling the straight crack defect of a surface edge of a medium-thick plate. The production method comprises the steps of steelmaking, chamfer blank continuous casting, chamfer blank angle part on-line cleaning, a casting blank entering a heating furnace for temperature rising and soaking, rough rolling, fine rolling, and finishing storing. A chamfer blank is provided with eight original chamfers, wherein in the step of chamfer blank continuous casting, the chamfer blank is produced through a chamfer crystallizer. After the chamfer blank goes out of a casting machine and before the chamfer blank goes into the heating furnace, on-line angle cleaning is conducted on angle parts of adjacent wide faces of the chamfer blank. After the on-line angle cleaning is conducted on the chamfer blank, thin and small occluded foreign substances, air holes and micro-segregation defects existing in the angle part of the casting blank can be eliminated, and the corner angle shape of the angle part, of the casting blank, of the adjacent wide faces can be changed, so that the high-temperature ductility of the angle part of the casting blank in the rolling process is improved, and tensile stress centralization in a transverse rolling process is reduced. Consequently, the production method can effectively control the occurrence of the straight crack defect of the edge of the medium-thick plate.

Description

technical field [0001] The invention belongs to the field of continuous casting and rolling of steel, and in particular relates to a production method for controlling straight crack defects on the surface of a medium-thick plate. Background technique [0002] In recent years, straight edge cracking has become the main surface quality problem of hot-rolled plate. Straight edge cracks are surface defects that appear on the edge of the steel plate parallel to the rolling direction and are approximately linear. The location is about 20-60 mm away from the edge of the plate, and the crack depth is more than 200 μm. The appearance is similar to the surface longitudinal crack. Micro-alloyed high-strength steels such as: pipeline steel, ship plate steel, automobile beam steel and other steel types are prone to edge cracking during the rolling process, and the occurrence rate can reach more than 80% in severe cases. It is common in large steel companies, and it has become one of the...

AI Technical Summary

Problems solved by technology

[0010] In terms of continuous casting production of chamfered slabs, the General Iron and Steel Research Institute proposed and developed the patented technology of chamfering crystallizers and chamfered foot rolls, which improved the corner crack defects of continuous casting slabs. In terms of straight crack defect control, there is currently no industrial production report on the use of chamfering molds to successfully eliminate or effectively control the straight crack defects at the edge of medium and thick plates

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