Thin-gauge martensitic steel strip and manufacturing method thereof

Abstract

The invention discloses a thin-gauge martensitic steel strip and a manufacturing method thereof. The thin-gauge martensitic steel strip is prepared from the following components in percentage by weight: 0.16-0.26% of C, 0.1-0.5% of Si, 0.4-1.7% of Mn, less than or equal to 0.02% of P, less than or equal to 0.007% of S, 0.004-0.010% of N, less than 0.001% of Als, 0.007-0.020% of total oxygen [O]<T>, and the balance of Fe and other inevitable impurities. Meanwhile, the thin-gauge martensitic steel strip meets the following requirements: the thin-gauge martensitic steel strip contains one or twoof 0.1-0.6% of Cu or 0.005-0.04% of Sn; the thin-gauge martensitic steel strip contains one or two of 0.01-0.08% of Nb and 0.1-0.4% of Mo; and Mn / S is greater than 250. The manufacturing method comprises the following steps: smelting molten steel by using residual Sn, Cu and other elements in scrap steel, and selectively adding Nb / Mo and other microalloy elements into the steel; in the smelting process, controlling the alkalinity of slag, the type and melting point of inclusions in the steel, the content of free oxygen in the molten steel and the content of acid-soluble aluminum Als; and thencarrying out double-roller strip continuous casting to cast a cast strip, and carrying out online hot rolling and gas atomization rapid cooling to obtain the thin-gauge martensitic steel strip.

Description

technical field [0001] The invention belongs to the continuous casting process, and in particular relates to a thin-gauge martensitic steel strip and a manufacturing method thereof. 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 residual elements ...

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

[0014] 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 inhomogeneous structure of the final product obtained after austenite transformation, resulting in unstable performance of the product

Therefore, it is difficult and challenging to use a thin strip continuous casting production line to produce some high-strength products required by the automotive industry and the petrochemical industry. Therefore, when using thin strip continuous casting to produce high-strength martensitic steel, the traditional composition should be copied Craftsmanship cannot be produced and requires a breakthrough in composition and craftsmanship

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