Medium-thickness ship plate steel with ultrahigh intensity and low-temperature impact toughness and manufacturing method thereof

Abstract

The invention relates to medium-thickness ship plate steel with ultrahigh intensity and low-temperature impact toughness and a manufacturing method thereof. The ship plate steel comprises the following components in percentage by weight: 0.04 to 0.10 percent of C, 0.15 to 0.35 percent of Si, 1.20 to 1.70 percent of Mn, less than or equal to 0.020 percent of P, less than or equal to 0.010 percent of S, 0.04 to 0.08 percent of Nb, 0.10 to 0.20 percent of TiO, 0.20 to 0.50 percent of Cu, less than or equal to 0.30 percent of Cr, 0.20 to 0.50 percent of Ni, 0.02 to 0.05 percent of Al, 0.1 to 0.3 percent of Mo and the balance of Fe and impurities. A process comprises the following steps of: performing heating, heat insulation, two-stage rolling and cooling treatment on a precast continuous casting in sequence to manufacture finished product ship plate steel. The ship plate steel has simple component design, high comprehensive mechanical performance and high welding performance; and the preparation process is simple and easy to manipulate.

Description

Technical field [0001] The invention relates to a special steel plate and a preparation process thereof, in particular to an ultra-high-strength medium-thick ship plate steel with excellent low-temperature toughness and a 550MPa yield strength and a manufacturing method thereof. Background technique [0002] Ship plate steel is one of the main special plate varieties for wide and heavy plates. my country is a big country in the shipbuilding industry and has a huge demand for ship sheet steel. According to relevant statistics, my country's shipbuilding industry completed 30 million tons last year and actually consumed 12 million tons of shipbuilding steel plates. With the rapid development of my country's shipbuilding industry, the shipbuilding industry is also increasingly large-scale and light-weight. Therefore, general-strength ship plates can no longer meet the needs of the hull, and the application proportion of high-strength, high-quality grade E and F-class ship plates is ...

AI Technical Summary

Problems solved by technology

[0005] The invention patent with the publication number CN101289728A proposes a high-strength and high-toughness steel plate with low yield ratio and high heat input welding. The yield strength exceeds 500 MPa, but the composition design is relatively complicated. The content of Mo is 0.10-0.40%. Low-temperature impact toughness The performance test results are limited to the condition of -40°C, which does not reach the performance index of F-grade (impact toughness at -60°C) ship plate steel, and its production process requirements are relatively strict. The slow cooling time is not less than 24h, which increases the difficulty of manufacturing;

[0006] The invention patent with the publication number CN101255528A proposes a niobium-containing steel plate with excellent ultra-low temperature toughness and its rolling method. Water spray cooling is used between finishing rolling, which increases the difficulty of control in actual production

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