56kg-grade ultrahigh-strength maritime work steel plate with low yield ratio and preparation method of 56kg-grade ultrahigh-strength maritime work steel plate

Abstract

The invention belongs to the field of steel and iron material preparation, and relates to a 56kg-grade low-yield-ratio ultrahigh-strength maritime work steel plate and a preparation method thereof. According to the component design, the steel comprises the following components of 0.05%-0.012% of C, 0.20%-0.50% of Si, 1.00%-1.50% of Mn, smaller than or equal to 0.015% of P, smaller than or equal to 0.005% of S, 0.010%-0.030% of Nb, 0.010%-0.030% of Ti, 0.20%-0.45% of Cr, 0.010%-0.035% of V, 0.20%-0.50% of Cu, 0.10%-0.25% of Mo, 0.50%-0.95% of Ni, 0.015%-0.045% of Als, smaller than or equal to 0.004% of N and the balance Fe and inevitable impurities, the carbon equivalent CeV is smaller than or equal to 0.55, and the carbon equivalent Pcm is smaller than or equal to 0.25. According to the method, Nb, V and Ti multi-element microalloying elements are utilized, Mo, Ni and other refined and precipitated second-phase particles are added, the refined grain strengthening and precipitation strengthening effects are improved, and the subcritical quenching and high-temperature tempering processes are combined, so that ReH of the steel plate is larger than or equal to 600 Mpa, Rm ranges from 730 Mpa to 800 Mpa, the yield ratio is smaller than or equal to 0.82, and transverse and longitudinal impact energy at the temperature of-60 DEG C is larger than or equal to 200 J; and meanwhile, formed second-phase particles are dispersed and distributed in a welding heat affected zone, the strength of a welding joint is improved, 150-220 kJ / cm input can be achieved, and the impact energy at the temperature of minus 60 DEG C after welding is larger than or equal to 100 J.

Description

Technical field [0001] The present invention belongs to the field of steel metallurgy, and specifically, a 56 kg of low-flexion ratio ultra high high sea industrial steel plate and a preparation method thereof. Background technique [0002] The construction of marine engineering is an important support for the national strategy of implementing marine powers. Its engineering seafood steel plate is mainly used for marine oil and gas exploitation, marine wind power, ship manufacturing and artificial island reef construction, long-term in wind, waves, flow, erode harsh environment It is extremely demanding for its performance requirements, and higher requirements for performance, low temperature toughness, welding and other performance. [0003] Ultra high intensity, low and flexor ratio and excellent low temperature toughness are the basic requirements of ships and marine engineering steel. Early large hull structures use steel plates below 235 MPa, with the continuous improvement o...

AI Technical Summary

Problems solved by technology

[0007] Patent document CN110791202 A discloses "A Machine Manufacturing Method of Low Yield Strength Ratio Marine Steel Plate with Good Welding Performance". This patent develops a 6-80mm thick marine steel plate suitable for large input energy welding through composition and process optimization. Strength ratio≤0.80, but the marine steel prepared by this method is 420MP grade, and it is only suitable for -40℃ environment

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