800 Mpa high-strength thick plate for high heat input welding

Abstract

The invention relates to a high-strength steel plate for high heat input welding, which comprises the chemical compositions by weight percentage as follows: C (0.05-0.10%), Si (0.05-0.20%), Mn (0.5-1.5%), P (less than or equal to 0.015%), S (less than or equal to 0.005%), Al (0.02-0.08%), N (0.002-0.005%), Cr (0.1-0.5%), Mo (0.1-0.5%), Cu (0.2-0.5%), Ni (1.0-4.0%), O (less than or equal to 0.0030%), and the balance of Fe and other unavoidable impurities. The steel can be manufactured by the traditional thermal mechanical control process (TMCP) and the rapid cooling process. The yield strength of the steel is greater than or equal to 700 Mpa, the tensile strength of the steel is greater than or equal to 800 Mpa, the thickness of the steel is less than 30mm, and the high-strength high-ductility steel plate is suitable for 40-100kj/cm weld heat input; an HAZ (heat affected zone) of the steel plate is very good in impact ductility even at subzero 40 DEG C; and the steel plate has an excellent comprehensive mechanical property.

Description

technical field [0001] The invention relates to structural steel, in particular to a thick plate for 800MPa-level high-strength large-input energy welding and a manufacturing method thereof. Background technique [0002] Low-alloy high-strength steel is one of the most used structural materials and is widely used in oil and gas pipelines, shipbuilding, bridges, high-rise buildings, pressure vessels and other industries. In order to improve production efficiency, the above-mentioned industries have higher and higher requirements on the strength and weldability of structural steel plates, especially the high-energy-input weldability. However, high-energy-input welding is likely to cause a very serious problem, that is, welding around the weld The toughness of the heat-affected zone (HAZ) is severely deteriorated, and brittle fracture is extremely prone to occur. For traditional low-alloy steels, the welding input energy generally does not exceed 40kJ / cm. In this case, the det...

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Problems solved by technology

At present, there is no 800MPa-level thick steel pla

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