A steel plate for polar ships and its manufacturing method

Abstract

The invention discloses a steel plate for a polar region ship and a manufacturing method of the steel plate. The steel plate comprises, by weight percentage, 0.02%-0.13% of C, 0.80%-1.2% of Si, 0.30% --1.00% of Mn, 0.40%-1.00% of Cr, 0.05%-0.40% of Ni, less than 0.010% of P, less than 0.005% of S, 0.01%-0.10% of Ti, less than 0.60% of Mo, 0.10%-0.80% of Cu, 0.01%-0.06% of Al, 0.003%-0.06% of Nb, 0-0.08% of V and the balance Fe and inevitable impurity elements. The steel plate can be used at ultralow temperature, the toughness is excellent, the yield strength of the steel plate is larger than or equal to 315 MPa, the extension strength of the steel plate is larger than or equal to 510 MPa, the Charpy impact energy is larger than or equal to 200 J in the environment with the lower temperature ranging from -80 DEG C to -60 DEG C, the CTOD breaking tenacity value is larger than or equal to 0.25 mm at the -60 DEG C, the welding connector impact power is larger than or equal to 64 J in the environment with the lower temperature ranging from -80 DEG C to -60 DEG C, and the welding performance is excellent.

Description

technical field [0001] The invention relates to a steel plate used for ships, in particular to a steel plate used for polar ships and a manufacturing method thereof. Background technique [0002] Ships built for polar regions, because they are used in low-temperature and cold seas, and the marine environment is complex and changeable, they have to withstand many challenges brought about by environmental factors such as ultra-low temperature, ice and snow abrasion, low-temperature wind wave collision, strong ocean storm and permafrost collision. Higher requirements are put forward for the design, material selection and construction processing of low temperature steel. [0003] The low-temperature steel used for polar ships requires excellent comprehensive performance at extremely cold and low temperatures. Its structural materials not only have high strength and good plasticity, but also require excellent impact toughness at -60°C and -80°C, especially in polar regions. Unde...

AI Technical Summary

Problems solved by technology

Its invention has obtained a low-temperature steel plate with good low-temperature toughness and its manufacturing method, but the chemical composition ratio of the steel plate invented by it is uncertain, which may easily lead to poor performance stability of the steel plate in mass production, or the addition of excessive alloy elements to ensure performance stability is not enough. high production cost

In addition, in this invention, the temperature at which the finish rolling starts is controlled below the Ar3 temperature and the tempered rolling steel plate can be carried out for large thickness specifications, but it is accompanied by the problems of slow production rhythm and low efficiency, and for thin gauge steel plates, due to the cooling of the steel plate itself Faster, so the adaptability of the core heating process using the steel plate is poor, the performance of the steel plate is difficult to guarantee, the actual implementation is difficult, and the effect is poor

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