Cold-rolled steel sheet with high yield ratio and excellent weather resistance

Abstract

There is provided a cold-rolled steel sheet with a high yield ratio, and excellent weather resistance and workability. The cold-rolled steel sheet including, by weight: 0.08 to 0.20% C, 0.1 to 0.5% Si, 0.9 to 2.0% Mn, <0.02% P, <0.01% S, 0.02 to 0.07% Al, 0.03 to 0.06% Nb, 0.05 to 0.30% Ni, 0.2 to 0.5% Cu, 0.3 to 0.6% Cr, 0.001 to 0.004% B, 0.02 to 0.08% Co, the balance being Fe and unavoidable impurities. Also, there is provided a method of manufacturing the same.

Description

technical field

[0001] The present invention relates to a high-strength cold-rolled steel plate with excellent weather resistance and a manufacturing method thereof for buildings, rail vehicles and containers, and more particularly, the present invention relates to a high-yield ratio and High-strength cold-rolled steel sheet with excellent weather resistance. Background technique

[0002] In order to reduce the weight or prolong the service life of containers or rail vehicles, materials such as stainless steel or aluminum are generally used. These products are required to have properties such as bendability, weldability and durability. In addition, means of transportation are susceptible to impact force when transporting or loading goods, and thus it is necessary to suppress deformation caused by the impact force. For this purpose, a steel material having a high yield ratio may be desirably used.

[0003] The yield ratio is defined as the ratio of the tensile strength to ...

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