Cooling method for 60-100mm performance-guaranteed thick steel plate after rolling

Abstract

The invention relates to a method for producing extra-thick steel plates with thickness greater than 60mm, in particular to a method for accelerated cooling of 60-100mm continuous cast performance-guaranteed steel plates after rolling. In the method, the extra-thick steel plates are cooled twice, wherein in the first cooling process, rapid cooling is adopted, the cooling speed of the surfaces of the steel plates is controlled to be above 12 DEG C per second and the cooling time is 8-15 seconds; and in the second cooling process, the cooling speed of the surfaces of the steel plates is controlled to be 4-8 DEG C per second. The method overcomes the disadvantages of low performance qualification rate of the extra-thick steel plates and high cost in conventional method. With the method, extra-thick steel plates with stable performance can be produced. The method is low in technical process requirement, simple in operation, short in production line and low in energy consumption and is convenient to popularize in large-scale production.

Description

Technical field [0001] In order to achieve the above, the present invention belongs to the technical field of steel rolling, and relates to a method for producing extra-thick steel plates with a thickness greater than 60mm, and specifically relates to a method for accelerated cooling after rolling of a continuous casting slab with a protective thickness of 60-100mm. Background technique [0002] With the rapid development of China's national economy and the continuous increase of super high-rise and long-span steel structure construction projects, the domestic machinery and construction thick plate market has an increasing demand for large unit weight, high strength and extra thick steel plates. The thickness of the steel plate continues to increase, and the performance requirements are getting higher and higher. According to the investigations of major domestic steel plants, it is found that during the production of low-alloy high-strength thick plates with a thickness of 60 mm o...

AI Technical Summary

Problems solved by technology

The thickness of the steel plate continues to increase, and the performance requirements are getting higher and higher. According to the investigation of major domestic steel mills, the production process of the low-alloy high-strength thick plate with a thickness of more than 60 mm is affected by problems such as the size of the continuous casting billet, the capacity of the rolling mill, and the cooling speed of the thick plate. , causing the steel plate to have disadvantages in terms of compression ratio, pass reduction, and cooling rate control. The performance pass rate of the steel plate after rolling is low, generally about 70%, and the microscopic grains are mostly coarse or mixed.

However, if the performance of the steel plate with a thickness of more than 60 mm is unqualified, it needs to be rescued by heat treatment, which affects the production efficiency; it not only increases the production cost of the steel plate, but also causes a backlog of steel plates on-line

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