HT 960 steel plate with excellent plasticity and toughness and manufacture method thereof

Abstract

An HT 960 steel plate with excellent plasticity and toughness and a manufacture method thereof. The HT 960 steel plate comprises, by weight, 0.07%-0.12% of C, Si no mare than 0.15%, 0.80% -1.20% of Mn, P no mare than 0.012%, S no more than 0.0030%, 0.30%-0.60% of Cr, 0.30%-0.60% of Mo, 1.00%-1.60% of Ni, 0.15%-0.45% of Cu, 0.0008%-0.0016% of B, 0.006%-0.014% of Ti, 0.010%-0.030% of Nb, 0.025%-0.060% of Als, 0.030%-0.060% of V, N no more than 0.0060%, O no more than 0.0040%, 0.001%-0.004% of Ca, residual Fe and unavoidable inclusions. A TMCP + tempering thermal treatment process is employed to obtain super high strong steel plate with tensile strength no less than 960 MPa, yield strength no less than 900 MPa, Charpy transverse impact work (separate value) no less than 47J at -60 DEG C, fracture elongation percentage delta 5 no less than 15%, uniform elongation percentage Ag no less than 6% and excellent weldability.

Description

technical field [0001] The present invention relates to ultra-high-strength steel plate and its manufacturing method, in particular to a kind of excellent plastic toughness HT960 steel plate and its manufacturing method, in the low C-ultra-low Si-medium Mn-(Cu+high Ni+Mo+Cr) alloying-(Ti +Nb+V+B) In the microalloyed composition system, the tensile strength ≥ 960MPa, the yield strength ≥ 900MPa, the -60℃ Charpy transverse impact energy (single value) ≥ 47J, and the elongation at break are obtained through the TMCP + tempering heat treatment process. δ 5 Ultra-high-strength steel plate with ≥15% and uniform elongation Ag≥6%, excellent weldability. Background technique [0002] As we all know, low-carbon (high-strength) low-alloy steel is one of the most important engineering structural materials, widely used in oil and gas pipelines, offshore platforms, shipbuilding, bridge structures, boiler containers, building structures, automobile industry, railway transportation and mac...

AI Technical Summary

Problems solved by technology

However, the steel plate manufacturing technology of this invention adopts controlled rolling+off-line quenching+tempering process; this not only has many manufacturing processes, long manufacturing cycle, high manufacturing cost, but also relatively high energy consumption in the manufacturing process (steel rolling is completed and naturally air-cooled to room temperature, followed by shot blasting, and then heated to the quenching temperature), which is not conducive to energy saving and environmental protection; more importantly, the off-line quenching + tempering process cannot fully exert the hardenability and hardenability potential of alloy elements, and the hardenability of elements 1. The hardenability cannot be maximized; therefore, in order to obtain the same level of strength and toughness, more alloying elements (especially Ni, Mo, Cr, etc.) must be added, which not only further increases the manufacturing cost, but also damages the weldability of the steel plate , especially for ultra-high-strength steel plates, the sensitivity to welding cold cracking is greatly increased, and welding preheating and postheating (ie PWHT) are required at higher temperatures. The range of suitable welding heat input is narrower, and the processing and manufacturing costs are correspondingly lower. greatly improved

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