High-strength fire-resistant and weather-resistant steel plate/strip and production method thereof

Abstract

The invention relates to a high-strength fire-resistant and weather-resistant steel plate / strip and a production method thereof. The steel plate / strip comprises the following chemical components in percent 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, 0.10-0.60% of Cu, 0.20-0.60% of Mo, 0.01-0.08%of Nb, 0.004-0.010% of N, less than or equal to 0.001% of Als, 0.007-0.020% of total oxygen [O]T and the balance Fe and inevitable impurities, wherein Mn / S is greater than 250; and Pcm is smaller than or equal to 0.27%. The production method comprises the following steps of: selectively adding micro-alloy elements such as Mo / Nb / Cr into steel, and controlling the alkalinity of slag, the type and melting point of inclusions in the steel, the content of free oxygen in molten steel and the content of acid-soluble aluminum Als; then casting a cast strip through double-roller thin strip continuouscasting, and then feeding the cast strip into an on-line rolling mill for hot rolling; and after rolling, cooling the strip steel in a gas atomization cooling mode, and finally coiling the strip steeldirectly into a steel coil.

Description

technical field [0001] The invention belongs to the continuous casting process, and in particular relates to a high-strength fire-resistant and weather-resistant steel plate / strip and a production method thereof. Background technique [0002] Most of the traditional thin strip steel is produced by multi-pass continuous rolling of the slab with a thickness of 70-200mm. The traditional hot rolling process is: continuous casting + slab reheating and heat preservation + rough rolling + finishing rolling + cooling + Coiling, that is, firstly obtain a cast slab with a thickness of about 200mm through continuous casting, reheat the cast slab and keep it warm, then perform rough rolling and finish rolling to obtain a steel strip with a thickness generally greater than 2mm, and finally process the steel strip Laminar cooling and coiling complete the whole hot rolling production process. If it is necessary to produce a steel strip with a thickness of less than 1.5mm (inclusive), it i...

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

[0019] However, due to its own rapid solidification process characteristics, thin strip continuous casting 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 inhomogeneous structure of the final product obtained after austenite transformation, which will lead to unstable product performance, especially forming performance.

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