X80 wide and heavy steel plate with good low-temperature toughness and for hot bends and production method thereof

Abstract

The invention provides an X80 wide and heavy steel plate with good low-temperature toughness and for hot bends and a production method thereof. The steel plate is prepared from 0.055%-0.080% of C, 0.16%-0.35% of Si, 1.55%-1.75% of Mn, 0.025%-0.050% of Nb, 0.011%-0.025% of Ti, 0.05%-0.09% of V, 0.21%-0.45% of Cr, less than 0.20% of Mo, less than 0.25% of Ni, less than 0.20% of Cu, 0.010%-0.035% ofAl, less than or equal to 0.010% of P, less than or equal to 0.002% of S, 0.001%-0.004% of N, and the balance of Fe and inevitable impurities. The production method comprises the steps of hot metal pretreatment, converter smelting, external refining, continuous casting, heating, rolling, cooling and heat treatment. A microstructure is a combination of bainite and ferrite.

Description

technical field [0001] The invention belongs to the field of low-carbon and low-alloy steels, and in particular relates to a X80-grade wide-thick steel plate with a thickness ≥ 26 mm and a width > 4300 mm for hot-simmering pipes for oil and gas transportation in low-temperature environments and a production method thereof. Background technique [0002] In order to improve the transmission efficiency of oil and gas pipelines, the transmission pressure and pipeline diameter are constantly increasing; in order to take into account the safety of pipeline operation, the corresponding steel for oil and gas pipelines is required to develop in the direction of high strength, thick wall, and large plate width. At the same time, as the construction of oil and gas pipelines continues to extend to remote, cold, geologically active areas, and the demand for steel for special environments such as low-temperature stations increases, the low-temperature toughness and plastic deformation r...

AI Technical Summary

Problems solved by technology

[0014] The object of the present invention is to overcome the above-mentioned problems and deficiencies and provide a kind of X80 grade ultra-wide, thick wall, high strength, high toughness, low yield ratio, high plasticity for low-temperature environment hot-simmering bending pipe with thickness ≥ 26 mm and width > 4300 mm Hot-rolled steel plates and their production methods solve the comprehensive performance matching problems of steel plates for hot-bending pipes in low-temperature environments, such as strength, low-temperature toughness, plastic deformation resistance, and heat treatment performance stability, as well as process limitations and microstructure performance control caused by increased width and thickness. Difficulty and other issues

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