High-strength and thin-gauge steel plate/strip with fire resistance and weather resistance and a production method thereof

Abstract

The invention relates to a high-strength and thin-gauge steel plate / strip with fire resistance and weather resistance and a production method thereof. The steel plate / strip comprises by weight, 0.02-0.06% of C, 0.1-0.55% of Si, 0.4-1.7% of Mn, less than or equal to 0.03% of P, less than or equal to 0.007% of S, 0.30-0.80% of Cr, 0.20-0.60% of Mo, 0.01-0.08% of Nb, 0.004-0.010% of N, less than 0.001% of Als, 0.001-0.006% of B, 0.007-0.020% of total oxygen [O]T and the balance Fe and inevitable impurities, and meanwhile, the steel plate / strip contains one or two of 0.10-0.60% of Cu and 0.005-0.04% of Sn; the Mn / S ratio is greater than 250; and the Pcm is less than or equal to 0.27%. According to the method, residual elements such as Sn and Cu in scrap steel are used for smelting, and the microalloy elements such as Mo / Nb / Cr and the B element are selectively added; the alkalinity of slag, the type and melting point of inclusions in steel, the content of free oxygen in molten steel and thecontent of acid-soluble aluminum Als are controlled; and double-roller thin-strip continuous casting is adopted, then a cast strip is subjected to online hot rolling, and a gas atomization cooling mode is adopted for cooling after rolling.

Description

technical field [0001] The invention belongs to the continuous casting process, in particular to produce a high-strength thin-standard refractory and weather-resistant steel plate / strip product. Background technique [0002] In the traditional steel production process, tin (Sn) and copper (Cu) are typical residual or harmful elements in steel. It is very difficult and expensive to fully remove Sn and Cu in the steelmaking process. Once the steel contains Sn , Cu, basically cannot be completely eliminated, and the content of Sn and Cu can only be reduced by diluting molten steel, which all lead to an increase in the cost of smelting steel products. [0003] In recent years, due to the continuous recycling of steel scrap, there are more and more scrap steel resources, and the electricity price has also continued to decrease. Domestic short-process electric furnace steelmaking based on scrap steel is increasingly rising, resulting in the gradual increase in the content of resid...

AI Technical Summary

Problems solved by technology

At the same time, the contact of high-temperature strip steel with cooling water will cause many problems: first, water spots (rust spots) will be formed on the surface of the strip steel, which will affect the surface quality; second, the cooling water used for laminar flow cooling or spray cooling It is easy to cause uneven local cooling on the surface of the strip, resulting in uneven microstructure inside the strip, resulting in uneven properties of the strip and affecting product quality; third, uneven local cooling on the surface of the strip will cause deterioration of the shape of the strip , affecting the shape quality

[0022] However, due to the rapid solidification process characteristics of thin strip continuous casting, the produced steel generally has the problems of uneven structure, low elongation, high yield ratio, and poor formability; The grains have obvious inhomogeneity, which will lead to the inhomogeneity of the final product structure obtained after austenite transformation, which will lead to unstable product performance, especially forming performance.

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