Hot-rolled steel plate/strip for sulfuric acid dew point corrosion resistance and manufacturing method thereof

Abstract

The invention discloses a hot-rolled steel plate / strip for sulfuric acid dew point corrosion resistance and a manufacturing method thereof. Residual Sn, Cu and other elements in steel scrap are fullyutilized for molten steel smelting, and Cr, Ti, Sb and other microalloy elements are selectively added; in a smelting process, the alkalinity of slag, a type and a melting point of inclusions in steel, a content of free oxygen in molten steel and a content of acid-soluble aluminum Als are controlled; and then a cast strip is cast by adopting double-roller thin strip continuous casting, directly enters a lower closed chamber with a non-oxidizing atmosphere after being discharged from a crystallization roller, and enters an online rolling mill for hot rolling under a closed condition, rolled strip steel is cooled by adopting a gas atomization cooling mode, and finally the strip steel is coiled. The steel can be widely applied to the field of products with sulfuric acid dew point corrosion resistance requirements in use environments such as tobacco baking equipment, air preheater heat exchange elements, conveying pipelines, flues, chimney manufacturing structural parts, boiler preheatersand economizer equipment in 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 hot-rolled steel plate / strip resistant to sulfuric acid dew point corrosion 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%) ...

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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

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