Method for controlling shape of low-alloy high-strength steel plate in controlled cooling phase

Abstract

The invention discloses a method for controlling the shape of a low-alloy high-strength steel plate in a controlled cooling stage. The method is used in a controlled rolling and cooling process for producing a steel plate; the shape of the steel plate after rolling is obtained by using a controlled cooling process, and the upper to lower water ratio of the steel plate, edge masking and the speed of the steel plate passing through a controlled cooling area in the cooling process are adjusted according to the shape of the steel plate after rolling so as to control the shape of the steel plate after controlled cooling, and thus, a low-alloy high-strength steel plate capable of meeting requirements is obtained. The product produced by using the method can eliminate shape defects, such as concave upward, concave downward, edge waves, center waves and the like, of the steel plate in the process of controlled cooling, improves the accuracy of the controlled cooling process, ensures that the texture and the performance of the steel plate are more uniform, and further enhances the yield rate of the product.

Description

technical field [0001] The invention belongs to the field of metallurgy, and in particular relates to a plate shape control method in the cooling stage when a medium-thick plate production line adopts a TMCP process to produce low-alloy high-strength steel plates. Background technique [0002] In recent years, the controlled rolling and controlled cooling (TMCP) process has been widely used to develop high-strength steels with different microstructures. figure 1 It is a schematic diagram of the production process of the existing medium and heavy plate using the TMCP process, in which 1 is a heating furnace, 2 is a four-roll mill, 3 is a steel plate, and 4 is a controlled cooling system. Due to the high-speed cooling rate of the steel plate, the unevenness of the steel plate cannot meet the product quality requirements due to uneven cooling, and the defects of the produced products are as follows: Figure 2a-Figure 2e ,in Figure 2a is the arch in the width direction of the...

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Problems solved by technology

Due to the high-speed cooling rate of the steel plate, the unevenness of the steel plate cannot meet the product quality requirements due to uneven cooling, and the defects of the produced products are as follows: Figure 2a-Figure 2e ,in Figure 2a is the arch in the width direction of the steel plate, Figure 2b Concave in the width direction of the steel plate, Figure 2c There are side waves in the length direction of the steel plate, Figure 2d The head of the steel plate is warped, Figure 2e Kowtow to the head of the steel plate

For example: pipelines above X70 grade, high-strength steel above Q550D, Q609D grade, etc., 70-80% of the products need to be rectified after offline because the plate shape does not meet the requirements, and 10% of the products can not meet the product quality requirements. , can only be changed to waste products, which will bring huge economic losses to the enterprise. At the same time, the problem of steel plate shape has become a bottleneck in the development of high-strength steel using TMCP technology

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