Production technology for 345MPa-level hot-rolled plate roll

Abstract

The invention discloses a production technology for a 345MPa-level hot-rolled plate roll. The 345MPa-level hot-rolled plate roll comprises the components in percentage by weight: 0.14-0.18 percent of C, 0.20-0.30 percent of Si, 1.35-1.50 percent of Mn, less than or equal to 0.10 percent of S, less than or equal to 0.20 percent of P, 0.015-0.045 percent of Als, 0.015-0.030 percent of Ti and the balance of iron and residual impurities. The production technology for the 345MPa-level hot-rolled plate roll comprises liquid iron pretreatment, RH refining, LF refining, continuous casting, heating through a heating furnace, rolling and coiling. According to the production technology for the 345MPa-level hot-rolled plate roll, the content of sulfide inclusions in the Q345B plate roll is reduced, the metallographic structure of the plate roll is improved, the matching property of the intensity and the extending rate performance is improved, the influence, which is caused by fluctuation of rolling parameters, on the performance of the Q345B plate roll is alleviated, and the stability of the quality of a product is guaranteed.

Description

technical field [0001] The invention relates to a production process of 345MPa hot-rolled coils. Background technique [0002] The alloy composition of the existing Q345B steel only uses the five major elements of C, Si, Mn, P, and S. Such an alloy composition has certain advantages in production costs, but it is more dependent on the stability of the rolling process. In the rolling process of large-scale industrial production, the rolling parameters (finish rolling temperature, coiling temperature, etc.) change to a certain extent. Under normal circumstances, there will be temperature fluctuations of 50-150°C. There will be a greater degree of fluctuation in temperature. [0003] The final rolling temperature and coiling temperature in the hot rolling process are parameters that are sensitive to the microstructure and properties of the steel. When the coiling temperature increases, the yield strength of the steel decreases, the elongation increases, and the coiling temper...

AI Technical Summary

Problems solved by technology

The Q345B steel using the conventional five major elements is highly sensitive to rolling temperature. Due to the large fluctuation of industrial production temperature, the phenomenon of high elongation and low strength often occurs, or low elongation and high strength. As a result, the strength and elongation properties do not match, and one of the properties does not meet the standard requirements

[0004] Traditionally, the process of converter smelting, continuous casting, hot delivery, and continuous steel rolling after heating is adopted. Since the LF furnace is not used for refining, the S element is controlled too high, resulting in too much sulfide inclusion content in the steel, which will also affect the extension of the material. rate affected

Although the production cost is low, the low yield will not only lead to some quality objections, but also damage the company's own image

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