Baoshan Iron & Steel Co., Ltd.

Weijun Feng

Li Ping Wang

Li Wang

Yong Zhong

Wei Xiong

Xiaoming He

Jianjun Zhi

Guangkui Hu

Junjie Huang

Yanglin Ke

Liyang Zhang

A high-formability and super-strength cold-rolled steel sheet and a manufacturing method thereof. The weight percentage of its components is: C 0.15-0.25%, Si 1.00-2.00%, Mn 1.50-3.00%, P&#x2264;0.015%, S&#x2264;0.012%, Al 0.03-0.06%, N&#x2264;0.008%, and the rest are Fe and inevitable impurities. The manufacturing method comprises the following steps: 1) smelting and casting; 2) heating to 1170&#x2dc;1230&#xb0; C. and performing thermal insulation; 3) performing hot rolling, the finish rolling temperature being 880&#xb1;30&#xb0; C., and coiling at 550&#x2dc;650&#xb0; C.; and 4) performing acid washing, cold rolling, and annealing, the cold rolling reduction being 40-60%, annealing at 860-920&#xb0; C., and performing slow cooling to 690-750&#xb0; C. with the cooling rate of 3&#x2dc;10&#xb0; C./s; performing rapid cooling at 240&#x2dc;320&#xb0; C., with the cooling speed &#x2265;50&#xb0; C./s, then heating to 360&#x2dc;460&#xb0; C., and performing thermal insulation for 100&#x2dc;500 s to cool to the room temperature at last. Finally, a high-formability, low-rebound property and super-strength cold-rolled steel sheet with the yield strength of 600&#x2dc;900 MPa, the tensile strength of 980&#x2dc;1150 MPa, the elongation of 17&#x2dc;25% is obtained.

High-formability and super-strength cold-rolled steel sheet

A high-formability, super-high-strength, hot-dip galvanized steel plate, the chemical composition of which comprises, based on weight percentage, C: 0.15-0.25 wt %, Si: 1.00-2.00 wt %, Mn: 1.50-3.00 wt %, P&#x2264;0.015 wt %, S&#x2264;0.012 wt %, Al: 0.03-0.06 wt %, N&#x2264;0.008 wt %, and the balance of iron and unavoidable impurities. The room temperature structure of the steel plate comprises 10-30% ferrite, 60-80% martensite and 5-15% residual austenite. The steel plate has a yield strength of 600-900 MPa, a tensile strength of 980-1200 MPa, and an elongation of 15-22%. Through an appropriate composition design, a super-high-strength, cold rolled, hot-dip galvanized steel plate is manufactured by continuous annealing, wherein no expensive alloy elements are added; instead, remarkable increase of strength along with good plasticity can be realized just by appropriate augment of Si, Mn contents in combination with suitable processes of annealing and furnace atmosphere control. In addition, the steel plate possesses good galvanization quality that meets the requirement of a super-high-strength, cold rolled, hot-dip galvanized steel plate for automobiles.

High-formability and super-strength hot galvanizing steel plate and manufacturing method thereof

The present invention discloses a superstrength cold rolled weathering steel sheet, wherein the weight percentage of the chemical elements thereof are as follows: C: 0.05&#x2dc;0.16%; Mn: 1.00&#x2dc;2.20%; Al: 0.02&#x2dc;0.06%; Cu: 0.20&#x2dc;0.40%; Cr: 0.40&#x2dc;0.60%; Ti: 0.015&#x2dc;0.035%; P: less than 0.03%; and C+Mn/16 is more than 0.19% and less than 0.23%; the remainders thereof being Fe and other unavoidable impurities. The present invention also discloses a method of manufacturing said superstrength cold rolled weathering steel sheet, comprising the following stages: smelting, heating and preservation, hot rolling, coiling, pickling, cold rolling, continuous annealing and skin passing. The advantages of the superstrength cold rolled weathering steel sheet and the method of manufacturing the same are: high strength, i.e., the yield strength more than 700 MPa and the tensile strength more than 1000 MPa; excellent performance of atmosphere corrosion resistance; thin so as to meet the demand of reducing the thickness and weight thereof; good shape and surface quality.

Superstrength cold-rolled weathering steel sheet and method of manufacturing same

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Shanghai, China

Weijun Feng