Production method of thin hot-rolled steel plate/strip for sulfuric acid dew point corrosion resistance

Abstract

The invention relates to a thin hot-rolled steel plate/strip for sulfuric acid dew point corrosion resistance and a production method thereof. Residual Sn, Cu and other elements in scrap steel are used fully to smelt molten steel, and Cr, Ti, Sb and other microalloy elements and B element are selectively added into the steel. The production method comprises the steps of: in a smelting process, controlling the alkalinity of slag, the type and melting point of inclusions in steel, the content of free oxygen in molten steel and the content of acid-soluble aluminum Als; and then casting a cast strip through double-roller thin strip continuous casting, feeding the cast strip into an on-line rolling mill for hot rolling under a closed condition, cooling strip steel in a gas atomization cooling mode after rolling, and finally conducting coiling. The steel disclosed by the invention can be widely applied to the field of products with sulfuric acid dew point corrosion resistance requirements inuse environments such as tobacco baking equipment, air preheater heat exchange elements, conveying pipelines, flues, chimney manufacturing structural parts, boiler preheaters and economizer equipmentin industries of petroleum, chemical engineering, electric power, metallurgy and the like.

Description

technical field [0001] The invention belongs to the continuous casting process in the metallurgical industry, and in particular relates to a production method of a thin gauge hot-rolled steel plate / strip for sulfuric acid dew point corrosion resistance. 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%)...

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

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