High-strength steel plate for ocean engineering and production method thereof

Abstract

The invention discloses a high-strength steel plate for ocean engineering and a production method thereof. The production method comprises the working procedures of smelting, continuous casting, heating, rolling, heat stacking and heat treatment, wherein the molten steel obtained in the smelting procedure comprises the following chemical ingredients with contents in percentage by mass: 0.05-0.09% of C, 0.10-0.30% of Si, 1.1-1.35% of Mn, not greater than 0.010% of P, not greater than 0.003% of S, 0.15-0.4% of Ni, 0.15-0.35% of Cr, 0.10-0.30% of Mo, 0.020-0.050% of Nb, 0.03-0.05% of V, 0.020-0.050% of TAl, and balance Fe and inevitable impurities; a quenching and tempering process is adopted in the heat treatment procedure; during the quenching process, a heating temperature is 880-910 DEG C, and a total heating time is PLC +(20-40) minutes; and during the tempering process, a heating temperature is 580-620 DEG C, a total heating time is 1.5-2 minutes per millimetre, and air cooling is carried out after discharge. According to the method disclosed by the invention, through adjustment and optimization for the proportion of alloy elements in the steel plate, and quenching and low-temperature short-time tempering, good mechanical properties of the steel plate can be guaranteed under a low-carbon-equivalent condition, and the steel plate is enabled to have good structure, comprehensive property and welding property.

Description

technical field [0001] The invention relates to a high-strength steel plate and a production method thereof, in particular to a high-strength steel plate for marine engineering and a production method thereof. Background technique [0002] With the continuous development of my country's ocean development, the exploitation of offshore oil has gradually developed into the deep sea area, especially in the context of the national development of ocean strategy, the construction of offshore platforms has ushered in a new period of rapid development. High-strength steel plates for offshore platforms are widely used in the manufacture of drill floors, spud shoes, cantilever beams, support rails, and other structures. They are characterized by high strength, high toughness, large thickness, good weldability, high technical content, and difficult production. [0003] The traditional high-strength tempered steel plate for marine engineering is designed with a high carbon content and ca...

AI Technical Summary

Problems solved by technology

Due to the high alloying elements such as carbon, it has a high welding crack sensitivity coefficient, which brings great difficulties to welding

In addition, the higher carbon content and carbon equivalent, in order to meet a certain strength and toughness matching, requires a high tempering temperature and a long time of heat preservation. The tempering temperature is generally higher than 650 ° C, and the time is not less than 4.5min / mm. The matrix is ​​fully softened, thus wasting a lot of heat treatment fuel energy