A kind of 80mm thick low-cost fh420 marine steel plate and its manufacturing method

Abstract

An 80mm-thick low-cost FH420 marine steel plate, components thereof being, in weight percentage: C: 0.07-0.11%, Si: 0.15-0.40%, Mn: 1.30-1.60%，P ≤ 0.013%, S ≤ 0.003%, Nb: 0.010-0.030%, V: 0.030-0.050%, Ti: 0.005-0.020%, Cr: 0.10-0.20%, Al: 0.0250-0.050%, O ≤ 18ppm, N ≤ 38ppm, H ≤ 2.5ppm, and the remainder being Fe and unavoidable impurities. The manufacture of present marine steel plate uses thermomechanical controlled processing. The heating temperature before rolling is 1150°C-1220°C, the rough rolling temperature is 980-1080°C, and the finish rolling starting temperature is 840-870°C. After rolling, laminar cooling is performed, the final cooling temperature being 600-660°C, and the cooling rate being 5-8°C / s. Quenching treatment is performed at a temperature of 890-910°C, the heating rate being 1.4min / mm and the holding time being 0-25min, and tempering treatment is performed at a temperature of 550-650°C, the heating rate being 2.0min / mm, and the holding time being 80-120min.

Description

technical field [0001] The invention relates to a steel for marine engineering, in particular to an 80mm thick low-cost FH420 marine steel plate and a manufacturing method thereof. Background technique [0002] my country's development of offshore oil started late, and it was not until the 1980s that it had its own offshore oil platform. In the past 10 years, domestic offshore platform steel plates have not been widely used in my country's offshore oil projects. At present, my country has basically realized the localization of steel for offshore platforms below EH36, accounting for 90% of the steel used for platforms. In the field of marine engineering equipment and high-tech ships, we will vigorously develop deep-sea exploration, resource development and utilization, offshore operation support equipment and its key systems and special equipment; promote the development and engineering of deep-sea space stations and large floating structures. The demand and requirements for s...

AI Technical Summary

Problems solved by technology

[0003] Invention patent CN 104674117 A provides a 420MPa grade ocean engineering steel plate and its manufacturing method, invention patent CN 104357742 A provides a 420MPa grade ocean engineering large thickness hot-rolled steel plate and its production method, which are disclosed by the above two patents The manufacturing method is controlled rolling and controlled cooling. Offshore equipment manufacturing enterprises have very high requirements on the performance uniformity and performance fluctuation value of 420MPa marine engineering steel. , Invention patent CN 104674117 A component design contains precious elements Ni, Cu, invention patent CN 104357742 A component design contains precious element Ni; moreover, the above two invention patents only meet the requirements of E-grade steel, not F-grade ultra-high-strength steel Industrial Steel Requirements

However, the FH420 marine steel delivered in the conventional quenched and tempered state contains a large amount of precious elements Ni, Mo, and Cu, which is expensive and will greatly increase the production cost of marine equipment companies.

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