420MPa-grade weather-resistant bridge steel and production method thereof

Abstract

The invention discloses 420MPa-grade weather-resistant bridge steel and a preparation method thereof. The 420MPa-grade weather-resistant bridge steel is prepared from the chemical components including, by mass, 0.05%-0.07% of C, 0.25%-0.50% of Si, 1.10%-1.70% of Mn, less than or equal to 0.020% of P, less than or equal to 0.010% of S, 0.28%-0.35% of Cu, 0.20%-0.30% of Ni, 0.45%-0.55% of Cr, less than or equal to 0.10% of Mo, 0.008%-0.030% of Nb, 0.010%-0.030% of Ti, 0.005%-0.015% of V, 0.020%-0.035% of Als, 0.0020%-0.0050% of Ca, less than or equal to 0.0040% of O, 0.0025%-0.0080% of N, and the balance Fe and inevitable impurities; and Nb/C+V/N is larger than or equal to 1.8 and is less than or equal to 3.5. The low-C-proper-Si and Mn-trace Nb-V-N alloying thought is adopted, the low-cost thought of high Cr and low Cu and Ni is adopted, a proper amount of Cu-Cr-Ni is added, the weather resistance is guaranteed, and the 420MPa-grade weather-resistant bridge steel which is low in cost, excellent in comprehensive performance, wide in production process window and capable of easily achieving batch industrial production is obtained, the composition system is matched with the optimized TMCP+tempering preparation technology, the requirement for the capacity of production equipment is reduced, and the steel is suitable for batch industrial production of small and medium-sized steel mills.

Description

technical field [0001] The invention relates to a 420MPa grade weather-resistant bridge steel and a production method thereof, belonging to the technical field of weather-resistant steel production. Background technique [0002] In recent years, bridge construction has developed rapidly. With the completion of the coating-free weather-resistant railway bridge spanning the Yarlung Zangbo River Zangmu Super Bridge and the coating-free weather-resistant highway bridge Guanting Reservoir Super Bridge, weathering steel has excellent mechanical properties, weldability and The weather resistance performance is more and more recognized by people, and the demand for weather resistance bridge steel in the construction of steel structure bridges is also increasing. At present, in order to achieve excellent performance indicators of mechanics, welding and weather resistance, the addition of Cu, Ni, V and other precious alloy elements in 420MPa weather-resistant bridge steel is relativel...

AI Technical Summary

Problems solved by technology

However, these technical ideas either have high alloy costs, or although the alloy costs are not high, they require high equipment capabilities, so they are not suitable for industrial production in small and medium-sized steel mills with average domestic equipment capabilities.

Therefore, it is urgent to develop a 420MPa-grade weather-resistant bridge steel with low

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