Rare-earth-containing cold-rolled weathering steel with yield strength of 310 MPa for automobiles and production method of rare-earth-containing cold-rolled weathering steel

Abstract

The invention relates to rare-earth-containing cold-rolled weathering steel with yield strength of 310 MPa for automobiles. The rare-earth-containing cold-rolled weathering steel comprises the following chemical components in percentage by weight: less than or equal to 0.09% of C, 0.10-0.40% of Si, 0.15-0.35% of Mn, 0.05-0.11% of P, less than or equal to 0.015% of S, 0.010-0.030% of Als, 0.2-0.35% of Cu and 0.04-0.09% of RE. A production method comprises the following steps of: conducting desulfurizing; heating a casting blank; scouring the surface of the casting blank with high-pressure water; conducting rough rolling; conducting finish rolling; conducting coiling; conducting cold rolling after pickling; conducting continuous annealing; and conducting leveling according to different cold-rolled finished product thicknesses. Under the condition that the yield strength is 310-380 MPa and the tensile strength is 400-480 MPa, the elongation A can be improved to be larger than or equal to 38%. The rare-earth-containing cold-rolled weathering steel has good atmospheric corrosion resistance and weather resistance, is simple in element and is particularly suitable for structural parts which cannot be coated in the automobiles and are large in stamping deformation.

Description

technical field [0001] The invention relates to a cold-rolled steel and a production method, which precisely belong to a rare earth-containing cold-rolled weather-resistant steel for automobiles with a yield strength of 310 MPa and a production method, which is especially suitable for automobiles that cannot be painted inside and have large stamping deformation structural parts. Background technique [0002] Atmospheric corrosion is the interaction between a material and its surrounding atmospheric environment, and ordinary steel materials are easily corroded (rusted) in the atmosphere. According to statistics, 1 / 6 of the world's annual steel production is lost due to corrosion, and the direct economic loss caused by steel corrosion in my country exceeds 10 billion yuan each year. [0003] Weathering steel is atmospheric corrosion-resistant steel, which is a small amount of alloying elements added to the steel, so that the steel forms a dense layer of about 50-100 μm thick ...

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Problems solved by technology

However, it adds 0.10%-0.25% Ni element and 0.3%-0.45% Cr element, the alloy cost is high, and the atmospheric corrosion resistance of the steel plate is not explained.

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