Baoshan Iron & Steel Co., Ltd.

Jianchun Wu

Yuan Fang

Yan Yu

Xiufang Wang

Bo Qin

Jian Zhang

Wei He

Feng Zhang

Disclosed are a hot-rolled steel plate/strip with sulfuric acid dew point corrosion resistance and a method for producing the same, wherein the hot-rolled steel plate/strip comprises the following chemical elements in weight percentages: C: 0.02-0.06%, Si: 0.10-0.55%, Mn: ≤1.5%, P≤0.03%, S≤0.007%, Ti: 0.03-0.15%, Cr: 0.50-1.20%, Ni: 0.10-0.30%, Sb: 0.04-0.30%, Cu: 0.20-0.60%, N: 0.004-0.010%, Als: <0.001%, one or both of Sn: 0.005-0.04% and B: 0.001-0.006%, Mn/S≥250, total oxygen [O]: 0.007-0.020%; and a balance of Fe and other unavoidable impurities. The steel can be widely applied to the fields of tobacco baking apparatuses, air preheater heat exchange elements in industries such as petroleum, chemical industry, electric power, and metallurgy, delivery pipe, flue, and stack manufacturing structural parts, and boiler preheater and economizer equipment, of which the use environments have requirements for sulfuric acid dew point corrosion resistance performance.

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

A method for producing ultra-thin hot-rolled strip steel, the method comprising the following process steps: A. a smelting process: feeding scrap steel into an induction electric furnace () for smelting so that the scrap steel melts into molten steel; B. a refining process: using a ladle refining furnace () and a ladle vacuum degassing furnace () to refine the molten steel; C. a continuous casting process: casting the refined molten steel into a cast strip blank that has a thickness of 1.6-2.5 mm by means of a dual-roller thin strip continuous casting system (); D. a hot rolling process: directly feeding the cast strip blank that was cast in the continuous casting process to a single-stand hot rolling mill () for rolling to produce hot-rolled strip steel, the thickness of the hot-rolled strip steel being 0.8-1.5 mm; E. a cooling coiling process: performing atomizing cooling on the hot-rolled strip steel, and coiling after the strip steel temperature is controlled to be 400-750° C. The present method achieves an extremely compact, environmentally-friendly and economical ultra-thin hot-rolled strip steel production process flow, and achieves the environmentally-friendly and economical continuous production of metal plates and strips.

Method for producing ultra-thin hot-rolled strip steel

A method for manufacturing thin strip continuously cast 700 Mpa grade high strength weather-resistant steel, the method comprising the following steps: 1) casting a 1-5 mm thick cast strip in a double roller continuous casting machine, the cast strip comprising the following chemical compositions by weight percent: C 0.03-0.1%, Si&#x2264;0.4%, Mn 0.75-2.0%, P 0.07-0.22%, S&#x2264;0.01%, N&#x2264;0.012%, and Cu 0.25-0.8%, further comprising more than one of Nb, V, Ti and Mo: Nb 0.01-0.1%, V 0.01-0.1%, Ti 0.01-0.1%, and Mo 0.1-0.5%, and the balance being Fe and unavoidable impurities; 2) cooling the cast strip at a rate greater than 20&#xb0; C./s; 3) hot rolling the cast strip under a temperature of 1050-1250&#xb0; C. at a reduction rate of 20-50% and a deformation rate greater than 20 s&#x2212;1; then conducting austenite online recrystallization, the thickness of the hot rolled strip being 0.5-3.0 mm; 4) cooling at a rate of 10-80&#xb0; C./s; and 5) rolling up under a temperature of 500-650&#xb0; C. The obtained steel strip microstructure mainly consists of uniformly distributed bainites and needle-shaped ferrites.

Method for manufacturing thin strip continuously cast 700MPa-grade high strength weather-resistant steel

A manufacturing method for strip casting 550 MPa-grade high strength atmospheric corrosion-resistant steel strip, comprising the following steps: 1) smelting, where the chemical composition of a molten steel is that: C is between 0.03-0.08%, Si&#x2266;0.4%, Mn is between 0.6-1.5%, P is between 0.07-0.22%, S&#x2266;0.01%, N&#x2266;0.012%, Cu is between 0.25-0.8%, Cr is between 0.3-0.8%, and Ni is between 0.12-0.4%, additionally, also comprised is at least one micro-alloying element among Nb, V, Ti, and Mo, where Nb is between 0.01-0.08%, V is between 0.01-0.08%, Ti is between 0.01-0.08%, and Mo is between 0.1-0.4%, and where the remainder is Fe and unavoidable impurities; 2) strip casting, where a 1-5 mm-thick cast strip is casted directly; 3) cooling the strip, where the cooling rate is greater than 20&#xb0; C./s; 4) online hot rolling the cast strip, where the hot rolling temperature is between 1050-1250&#xb0; C., where the reduction rate is between 20-50%, and where the deformation rate is &#x3e;20 s; austenite online recrystallizing after hot rolling, where the thickness of the hot rolled strip is between 0.5-3.0 mm; and, 5) cooling and winding, where the cooling rate is between 10-80&#xb0; C./s, and where the winding temperature is between 570-720&#xb0; C. The microscopic structure of a steel strip acquired is primarily constituted by fine polygonal ferrite and pearlite.

Manufacturing method for strip casting 550 MPa-grade high strength atmospheric corrosion-resistant steel strip

A manufacturing method for strip casting 700 MPa-grade high strength atmospheric corrosion-resistant steel, comprising the following steps: 1) smelting, where the chemical composition of a molten steel in terms of weight percentage is that C is between 0.03-0.1%, Si&#x2266;0.4%, Mn is between 0.75-2.0%, P is between 0.07-0.22%, S&#x2266;0.01%, N&#x2266;0.012%, Cu is between 0.25-0.8%, Cr is between 0.3-0.8%, and Ni is between 0.12-0.4%, additionally, also comprised is at least one micro-alloying element among Nb, V, Ti, and Mo, where Nb is between 0.01-0.1%, V is between 0.01-0.1%, Ti is between 0.01-0.1%, and Mo is between 0.1-0.5%, and where the remainder is Fe and unavoidable impurities; 2) strip casting, where a 1-5 mm-thick cast strip is casted directly; 3) cooling the cast strip, where the cooling rate is greater than 20&#xb0; C./s; 4) online hot rolling the cast strip, where the hot rolling temperature is between 1050-1250&#xb0; C., where the reduction rate is between 20-50%, and where the deformation rate is &#x3e;20s; austenite online recrystallizing after hot rolling, where the thickness of the hot rolled strip is between 0.5-3.0 mm; and, 5) cooling and winding, where the cooling rate is between 10-80&#xb0; C./s, and where the winding temperature is between 520-670&#xb0; C. The microscopic structure of a steel strip acquired is primarily constituted by evenly distributed bainite and acicular ferrite.

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Shanghai, China

Jianchun Wu