460MPa-grade high-toughness low-alloy high-strength structural steel plate and production method thereof

Abstract

The invention discloses a 460MPa-grade high-toughness low-alloy high-strength structural super-thick steel plate. The chemical ingredients of the steel plate comprise 0.03-0.09% of C, 0.10-0.40% of Si, 1.20-1.60% of Mn, 0.01-0.05% of Nb, 0.005-0.030% of Ti, 0.01-0.04% of V, 0.015-0.045% of Als, 0.015% or smaller of P and 0.008% or smaller of S, and further comprise one or two kinds of 0.01-0.30% of Cr, 0.01-0.08% of Mo and 0.05-0.25% of Ni, and the balance Fe. A production method comprises the steps of smelting, refining, continuous casting, steel billet heating, controlled rolling, controlled cooling, slow cooling and obtaining of the finished product. The super-thick steel plate is good in performance, the impact energy KV2 at -60 DEG C of the 100 mm thick plate is larger than or equal to 200 J, the carbon equivalent is not larger than 0.38, the yield ratio is smaller than or equal to 0.85, the cost is low, the production process is simple, and operation is easy.

Description

technical field [0001] The invention belongs to the field of production technology of low-alloy high-strength structural steel plates, and in particular relates to a 460MPa-grade high-toughness low-alloy high-strength structural steel plate and a production method thereof. Background technique [0002] With the development of energy, chemical industry, hydropower, construction machinery and other fields, the market demand for low-alloy high-strength structural steel is increasing day by day. In order to meet the development trend of lower self-weight and higher loading capacity of engineering structures in the above industries, the yield strength is 460MPa (EN10025 -4: In 2004, the grades are S460M and S460ML; in GB / T 1591-2008, the grade is Q460) and the amount of steel plates with better welding performance is increasing. Some steel plates of this strength level are produced by quenching + tempering (quenching and tempering) after rolling, and some are produced by normaliz...

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Problems solved by technology

Some steel plates of this strength level are produced by quenching + tempering (quenching and tempering) after rolling, and some are produced by normalizing after rolling. The above two production methods not only have a carbon content of about 0.16% (wt%) , the same below), the carbon equivalent is mostly not less than 0.42%, and noble alloy elements such as Mo, Cr, Cu, Ni, V are also added, and the production cycle is long and the energy consumption is high; although some adopt thermomechanical rolling (TMCP ), which shortens the production process, but its carbon equivalent is mostly around 0.40%, and the carbon content is ≥0.12%, while the Q460 steel plate produced by TMCP and the carbon content is ≤0.10% due to Mo, Cr, Cu , Ni, V and other noble alloy elements are added in large quantities to increase the cost

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