High-strength thick steel plate for large heat input welding

Abstract

The invention relates to a high-strength thick steel plate for large heat input welding. The high-strength thick steel plate comprises, by weight percent, 0.07-0.10% of C, 0.05-0.15% of Si, 1.5-1.8% of Mn, not more than 0.01% of P, not more than 0.005% of S, 0.02-0.10% of Al, 0.006-0.02% of N, 0.005-0.015% of Ti, 0.10-0.25% of Cr, 0.0015-0.0025% of B, not more than 0.0030% of O, and the balance Fe and other inevitable impurity. A manufacture method of the high-strength thick steel plate includes: smelting in a converter or an electric furnace, secondary refining in a vacuum furnace, casting ingots, reheating the ingots, and performing TMCP (thermal mechanical control processing) and fast cooling to obtain the steel plate. The thick steel plate with a high strength of 600MPa is low in cost, and has excellent low-temperature toughness in the large heat input welding.

Description

technical field [0001] The invention relates to a thick steel plate for high heat input welding and a manufacturing method thereof, in particular to a thick steel plate for 600MPa grade high strength and low cost large heat input welding and a manufacturing method thereof. Background technique [0002] Low-alloy high-strength steel is one of the most widely used structural materials in engineering applications, and is widely used in oil and gas pipelines, shipbuilding, bridges, high-rise buildings, pressure vessels, oil storage tanks and other industries. In order to improve production efficiency, the above-mentioned industries have higher and higher requirements on the weldability of steel plates, especially the weldability of large heat input, but high heat input welding can easily cause the toughness of the weld seam and its surrounding welding heat-affected zone (HAZ) Severe deterioration makes welded joints prone to brittle fracture. For traditional steel plates such a...

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Problems solved by technology

In fact, the addition of Nb is detrimental to the large input energy weldability of steel, but this adverse effect is not obvious when the welding input energy is small (<100kJ / cm).

[0006] Although CN101050504A and CN101407893A claimed that HAZ has excellent low-temperature toughness after high-energy input welding, they did not provide welding thermal simulation or physical welding process conditions

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