Manufacturing method of high-surface-quality extra-thick plate

Abstract

The invention discloses a manufacturing method of a high-surface-quality extra-thick plate. The method comprises a blank heating step, a rough rolling step, a finish rolling step and a cooling step, and the method is characterized in that in the blank heating step, the temperature of a soaking zone is 1180-1260 DEG C, the descaling is greater than or equal to one time, and the descaling pressure is greater than or equal to 20MPa; a blank is cooled to 980-1020 DEG C after being descaled, and rolling is carried out; in the rough rolling step, descaling is carried out for greater than or equal to 2 times in the rough rolling process, and the descaling pressure is greater than or equal 20MPa; the time from rough rolling to finish rolling is less than or equal to 8 min; in the finish rolling step, the initial rolling temperature is less than or equal to 950 DEG C, the finish rolling temperature is 760-920 DEG C, descaling is carried out for greater than or equal to 2 times in the finish rolling process, and the descaling pressure is greater than or equal to 20 MPa; in the cooling step, cooling is conducted immediately after rolling, the steel polishing speed is greater than or equal to 5 m / s, and the temperature of the cooled steel plate is less than or equal to 700 DEG C; and the stacking temperature is 400-570 DEG C. According to the method, the surface quality of the extra-thick plate with the thickness specification greater than or equal to 50 mm can be improved, the surface of the steel plate is free of watermarks or piebaldness, and the surface quality is good; and meanwhile, the temperature after rough rolling can be effectively reduced, and the production efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of steel rolling production, and relates to an extra-thick plate with high surface quality and a manufacturing method thereof, in particular to a method for improving and controlling the surface quality of a steel plate with a thickness specification ≥ 50 mm under the rolling mode of a double-stand rolling mill for a 5000 mm wide and thick plate. Background technique [0002] With the development of large-scale, modern and intelligent equipment in domestic iron and steel enterprises, the problem of poor mechanical properties of thick-gauge steel plates has been basically improved, but surface defects of steel plates, such as water marks or mottled defects after shot blasting, have gradually emerged. The poor surface quality of the steel plate has a great impact on the subsequent painting process. Since such defects need to be found after shot blasting, the light can only be illuminated obliquely on the surfa...

AI Technical Summary

Problems solved by technology

At the same time, due to the improvement of the dimensional accuracy of the medium-thick plate and the pressure of cost reduction, the thickness of the steel plate is generally controlled by the deviation. Once the surface defect of the steel plate appears, the size is difficult to meet the requirements after grinding

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