High-corrosion-resistance steel and manufacturing method thereof

Abstract

The invention discloses high-corrosion-resistance steel and a manufacturing method thereof. The high-corrosion-resistance steel comprises the following chemical components of, in percentage by weight,0.02%-0.06% of C, 0.1%-0.5% of Si, 0.4%-1.7% of Mn, less than or equal to 0.02% of P, 4.0%-6.0% of Cr, 1.0%-3.0% of Ni, 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 Fe and other inevitable impurities. The steel further comprises one or two of 0.1%-0.6% of Cu and 0.005%-0.04% of Sn, and in addition, Mn / S is greater than 250. According to the steel, the residual Sn, Cu and other elements in the scrap steel are utilized to smelt molten steel, and Cr, Ni and other alloy elements are selectively added into the steel; in a smelting process, the alkalinity of slag, a type and a melting point of an inclusion in steel, a content of free oxygen in the molten steel and a content of acid-soluble aluminum Als are controlled; and then a cast strip with a thickness of 1.5-3 mm is cast through a double-roller thin strip continuous casting process, and a steel coil is obtained after hot rolling, gas atomization cooling and coiling.

Description

technical field [0001] The invention belongs to continuous casting technology and products in the metallurgical industry, in particular to a high corrosion-resistant steel and a manufacturing method thereof. Background technique [0002] 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 such as Sn and Cu in steel. Sn and Cu in steel are elements that are easy to segregate, and are easy to accumulate at the grain boundary to cause defects such as cracks. Therefore, the content of Sn and Cu elements in the traditional process is strictly controlled. In ordinary structural steel, the Sn , Cu content have clear requirements: Sn (wt%) ≤ 0.005%; Cu (wt%) ≤ 0.2%. [0003] In the traditional steel pr...

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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

[0020] (1) Long process flow, high energy consumption, many units and equipment, and high infrastructure costs lead to high production costs

[0021] (2) Corrosion-resistant steel contains a relatively high content of copper and other segregation-prone elements that improve the corrosion resistance of the steel strip. The traditional process is prone to macro-segregation of copper and other elements due to the slow solidification and cooling of the slab, resulting in various segregation of the slab. Anisotropy and macro cracks appear, and the yield is low

As a result, the corrosion resistance of the steel strip is not high

[0023] (4) The corrosion resistance of these corrosion-resistant steels cannot achieve the corrosion resistance requirements of the steel of the present invention, that is, it is doubled on the basis of traditional corrosion-resistant steels

[0024] (5) In the traditional process, since the microalloying elements cannot be maintained as a solid solution during the hot rolling process, partial precipitation occurs, resulting in fine grains of the steel structure, increased yield ratio, and poor formability, which will significantly increase the rolling load. Increase energy consumption and roll consumption, and cause greater damage to equipment, thus limiting the economical and practical production of high-strength corrosion-resistant steel hot-rolled products. Thickness range, usually ≤ 2mm

This not only increases the investment cost, but also significantly increases the floor area of ​​the thin strip continuous casting and rolling production line, reducing the advantages of the production line

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