Cold-rolled economical weathering steel with yield strength of 280 MPa for automobiles and production method of cold-rolled economical weathering steel

Abstract

The invention discloses cold-rolled economical weathering steel with yield strength of 280 MPa for automobiles. The cold-rolled economical 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, 0.15-0.45% of Mn, 0.05-0.12% of P, less than or equal to 0.015% of S, 0.010-0.030% of Als and 0.2-0.4% of Cu. 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 the thickness of different cold-rolled finished products. According to the cold-rolled economical weathering steel, the elements are simple, and only cheap alloy elements such as Mn, Si and P are added; the occurrence probability and degree of Cu brittleness and scale are reduced, and the surface quality of a steel plate is improved; and the hot rolling coiling temperature and a cold rolling flattening elongation process are designed according to the thickness of the finished products, so that the uniformity and stability of the mechanical properties of the finished products with different thicknesses are ensured; the processing formability is good, the precision is high, and the atmospheric corrosion resistance is excellent; and the cold-rolled economical weathering steel is particularly suitable for structural parts which cannot be coated in the automobiles.

Description

technical field [0001] The invention relates to a cold-rolled steel and a production method, and specifically belongs to an economical weather-resistant steel for cold-rolled automobiles with a yield strength of 280MPa and a production method. 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 amorphous state with good adhesion to the base metal between the rust layer and the matrix. The spinel oxide film, due to the existence of...

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Problems solved by technology

However, it adds 0.10%-0.25% Ni element and 0.3%-0.45% Cr element, and the cost of the alloy is relatively high

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