High-elongation hot-rolled microstructure regulating steel with tensile strength greater than or less than 800MPa and production method thereof

Abstract

The invention discloses high-elongation hot-rolled microstructure regulating steel with tensile strength greater than or less than 800MPa. The steel comprises the following components in percentage byweight: 0.07-0.09% of C, 1.95-2.10% of Mn, 0.70%-0.80% of Si, less than or equal to 0.008% of P, less than or equal to 0.002% of S and 0.02-0.04% of Als; the production method comprises the followingsteps of: carrying out RH vacuum furnace treatment after converter smelting; heating a casting blank; rolling in sections; variable speed cooling in sections: coiling; heat insulation; smoothing treatment. Under the premise of ensuring the tensile strength above 800MPa, the steel can make the yield strength be greater than or equal to 500MPa, elongation greater than or equal to 25%, product of strength and elongation greater than or equal to 20GPa% and yield ratio less than 0.65, the steel can meet the forming requirement of thick specifications and high strength steel, and alloy elements aresimple without adding precious alloys such as Nb, V, Mo, etc.; and the alloy cost can be reduced by at least 10%.

Description

technical field [0001] The invention relates to a hot-rolled steel for automobiles and a production method thereof, in particular to a high-elongation hot-rolled structure control steel with a tensile strength greater than 800MPa and a production method thereof; and is suitable for steel plates with a thickness of 2-12mm. Background technique [0002] In recent years, the automotive industry, especially commercial vehicles, semi-trailers, passenger cars and other market segments, has become more and more urgent to reduce weight. Related manufacturers have put forward clear requirements for vehicle weight reduction to meet the mandatory national standard GB1589-2016, etc. regulatory requirements. On the one hand, the wheels, axles, saddles and other structural parts of commercial vehicles and other models need to be drawn, reamed and other forming processes in the manufacturing process. There are clear requirements for edge forming performance. On the other hand, the thickne...

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Problems solved by technology

The lower limit of the elongation in this document is only 15%, which cannot meet the forming requirements of deformed and complex parts. At the same time, the thickness of the finished product is only 1.2-4.0mm, which cannot meet the needs of thicker specification steel, and there are many alloy elements, and the relative cost is high.

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