High-performance low-carbon bainite construction steel and producing method thereof

Abstract

The invention provides high performance low-carbon bainitic structure steel which includes the chemical components that C occupies 0.04 to 0.07 percent, Si occupies 0.20 to 0.50 percent, Mn occupies 1.50 to 1.80 percent, Nb occupies 0.03 to 0.06 percent, Ti occupies 0.005 to 0.030 percent, Cr occupies 0.25 to 0.50 percent, Cu occupies 0.30 to 0.60 percent, Ni occupies 0.20 to 0.50 percent, Als occupies 0.010 to 0.070 percent, and the residual is Fe and inevitable foreign impurities. The rolling process adopts the TMCP+RPC technology, the heating temperature before rolling is 1050 to 1220 DEG C, two stages are adopted to control the rolling, the rolling temperature in the re-crystallizing area is controlled to be higher than or equal to 1000 DEG C, the rolling temperature in the non-recrystallizing area is controlled to be 950 DEG C to (Ar3+0 to 100 DEG C), the rolling accumulated deformation amount in the non-recrystallizing area is larger than 50 percent, the relaxation after rollingis 10 to 120 seconds, then cooling is speeded up, the final cooling temperature is 380 to 530 DEG C, and then air cooling is performed. The cost of the invention is low, complex heat treatment is notrequired, the bainitic organization can be obtained without the mass adjustment, and the invention has high strength and high tenacity, as well as the welding and the weather resistance performance are good.

Description

technical field [0001] The invention belongs to the technical field of metal materials, and in particular relates to a low-alloy high-performance steel and a manufacturing method thereof. Background technique [0002] Reducing the initial construction costs and maintenance costs of steel bridges during their service has always been the focus of attention. With the development of bridge technology, bridges have higher and higher requirements for the strength, toughness, earthquake resistance and corrosion resistance of steel. Therefore, steel for modern bridges should have high performance, that is, excellent strength, toughness, good weldability, low yield ratio and good atmospheric corrosion resistance. In the past, the steel types with atmospheric corrosion resistance were mainly developed by the method of high P, Cu, supplemented with Cr, Ni and other alloying elements. The added P content is relatively high and the Mn content is relatively low. Their common shortcoming...

AI Technical Summary

Problems solved by technology

This patented steel grade is produced by controlled rolling and controlled cooling process, and contains the more expensive alloying element Mo, so the production cost is higher

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