Ultra-low-carbon bainite steel and producing method thereof

Abstract

The present invention is super-low carbon bainite steel and its production process. The chemical components include C0.01-0.05 wt%, Si 0.05-0.5 wt%, Mn 1.0-2.2 wt%, Nb 0.015-0.070 wt%, Ti 0.005-0.03 wt%, B 0.0005-0.005 wt%, Al 0.015-0.07 wt%, Mo 0.0-0.5 wt%, Cu 0.0-1.8 wt%, Ni 0.0-1.0 wt% and Cr 0.0-0.70 wt% except Fe and evitable impurity. The super-low carbon bainite steel is produced in controlled rolling and controlled cooling process. It has toughness-to-brittleness conversion temperature below -80 deg.c, excellent cold bending formation performance, simple production process, low cost and serial strength, and may be used widely in engineering machinery, mining and excavating machine, heavy truck, pipeline, container, bridge, ship, cargo transporter, marine facility, etc.

Description

technical field [0001] The invention belongs to the field of metal materials, in particular to an ultra-low carbon bainite steel and a production method thereof. Background technique [0002] Ultra-low carbon bainitic steel is a new steel system with high strength, high toughness and excellent welding performance developed in the world in recent years. combined product. The ultra-low carbon bainitic steel developed in the early stage has high content of Cr and Ni elements, high cost and difficult production. For example, the patent (TW258757, inventor JANG J, etc.) applied by Taiwan China Iron and Steel Federation "production process of low manganese ultra-low carbon bainite steel (ULCB) with good weldability and corrosion resistance" applies Mo -Ni-Nb system to obtain ultra-low carbon bainite steel. Its disadvantages are that the content of Mn is low, and the addition of alloy elements such as Mo and Ni is large, which increases the cost of the steel, and the effect of p...

AI Technical Summary

Problems solved by technology

Its disadvantages are that the content of Mn is low, and the addition of alloy elements such as Mo and Ni is large, which increases the cost of the steel, and the effect of promoting the bainite transformation of the entire structure is not ideal, so the strength level of the steel is not high, and there is no formation Serialized products

[0003] Another example: In the research paper on ultra-low carbon bainite steel published by Bcthlchcm Steel in the United States, the deficiency of the chemical composition of ultra-low carbon bainite steel lies in the high content of precious elements Cr and Mo (Cr2.23 %, Mo2.35%), the cost of steel is greatly increased, and too high Cr and Mo will cause tempering cracks and reduce the toughness of steel

Also did not form serialized products according to market demand