Mobile ocean platform steel with yield ratio not greater than 0.65 and production method thereof

Abstract

The invention provides mobile ocean platform steel with yield ratio not greater than 0.65. According to the thickness of the finished product of the mobile ocean platform steel, the mobile ocean platform steel being 8 to 50mm in thickness comprises the following components in percentage by weight: 0.08 to 0.12% of C, 0.20 to 0.35% of Si, 1.10 to 1.60% of Mn, not greater than 0.018% of P, not greater than 0.008% of S, 0.10 to 0.20% of Ni, 0.07 to 0.17% of Mo, 0.005 to 0.015% of Ti, 0.015 to 0.035% of Als, and not greater than 0.008% of N; the mobile ocean platform steel being more than 50 to 80mm in thickness comprises the following components in percentage by weight: 0.08 to 0.12% of C, 0.20 to 0.35% of Si, 1.10 to 1.60% of Mn, not greater than 0.010% of P, not greater than 0.004% of S, 0.10 to 0.20% of Ni, 0.10 to 0.20% of Cr, 0.07 to 0.17% of Mo, 0.005 to 0.015% of Ti, 0.015 to 0.035% of Als, and not greater than 0.008% of N. The production method comprises the following steps of: smelting through a converter; continuously casting to obtain a blank; heating the casting blank; roughly rolling; performing finish rolling; cooling; normalizing; performing fog cooling to the steel being not less than 50 to 80mm in thickness. The mobile ocean platform steel has the yield ratio of being not greater than 0.65, is stable in comprehensive performance and outstanding in welding performance, and can completely meet the requirements of the mobile ocean platform steel.

Description

technical field [0001] The invention relates to a steel for marine engineering and a production method thereof, in particular to a steel for a mobile offshore platform with a yield ratio ≤ 0.65 and a production method thereof. Background technique [0002] In recent years, countries have vigorously developed the marine economy, the demand for steel for marine engineering is increasing, and marine structural engineering is developing towards large-scale and deep-sea development. When exploiting oil and gas resources with a water depth exceeding 500m, the economy of fixed offshore platforms is low. Therefore, the mobile offshore platform is the main development direction of future ocean engineering. When the mobile offshore platform is in service, the steel structure bears large fluctuations in load. Reducing the yield ratio of the material (the ratio of yield stress YS to tensile strength TS) can greatly improve the ability of the platform structure to withstand sudden disast...

AI Technical Summary

Problems solved by technology

[0007] The present invention provides a yield strength R eL ≥360MPa, tensile strength R m ≥560MPa, yield ratio ≤0.65, elongation A≥26%, -40°C Charpy impact absorption energy transverse > 100J, CE≤0.43%, steel plate thickness 8~80mm and yield ratio ≤0.65 mobile offshore platform Steel and production method

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