Production method of atmospheric-corrosion-resistant high-strength extra-thick Q390GNH steel plate

Abstract

The invention discloses a production method of an atmosphere-corrosion-resistant high-strength extra-thick Q390GNH steel plate, the thickness of the steel plate is 120mm, the steel plate contains the following chemical components: C, Si, Mn, P, S, Nb, Cr, Ni, Cu, Ti, B and the balance of Fe and residual elements, the carbon equivalent Ceq is less than or equal to 0.42, and the welding crack sensitivity index Pcm is less than or equal to 0.20. The production method of the steel plate comprises the following steps: continuous casting, controlled rolling and controlled cooling, stack cooling and heat treatment processes, the steel plate with the thickness of 120mm is produced by adopting a casting blank with the thickness of 450mm, dendritic crystals in the steel are fully crushed in cooperation with large rolling reduction of 40-50mm and a hard shell rolling method, and finally recrystallized grains become fine in cooperation with repeated cooling, so that ideal martensite and ferrite structures are obtained, and the advantages of corrosion resistance, obdurability, low yield ratio, good welding performance and the like of the steel plate are realized.

Description

technical field [0001] The invention relates to the technical field of wide and thick plate production, in particular to a production method of atmospheric corrosion-resistant high-strength and extra-thick Q390GNH steel plate. Background technique [0002] Weathering steel, as a new generation of advanced steel material, has atmospheric corrosion resistance 2 to 5 times that of ordinary carbon steel, and the longer the service time, the more prominent the corrosion resistance. Due to its characteristics of rust resistance, no coating, thinning and consumption reduction, labor saving and energy saving, it can be applied to steel structures exposed to the atmosphere for a long time, such as buildings, vehicles, bridges, and towers, and can also be used to manufacture containers, railways, etc. Vehicles, oil derricks, harbor buildings, oil production platforms and other structural parts. [0003] The existing Q390 weathering steel has high sensitivity to welding cracks. At the...

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Problems solved by technology

[0003] The existing Q390 weathering steel has high sensitivity to welding cracks. At the same time, there are problems such as difficulty in producing crack-stopping extra-thick high-performance steel plates with the existing technology, special requirements for process equipment, unstable quality, and long process routes.

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