Method for producing super-thick steel plate

Abstract

The invention discloses a method for producing a super-thick steel plate. The method comprises the following production process steps of: performing pretreatment on molten iron; making steel by using a convertor; performing external refining; continuously casting; heating; rolling; cooling in an accelerated way; normalizing; controlling a cold condition; finishing; inspecting performance; and performing ultrasonic flaw detection. In the method, a low-C high-Mn component system is utilized, and Ni and Cu alloy elements are added into the steel in combination with micro-alloying treatment of Nb, V and Ti. The steel comprises the following chemical components in percentage by weight: less than or equal to 0.12 percent of C, 0.20 to 0.40 percent of Si, 1.20 to 1.50 percent of Mn, less than orequal to 0.008 percent of P, less than or equal to 0.003 percent of S, 0.03 to 0.06 percent of AlT, less than or equal to 0.10 percent of Nb, Ti and V, less than or equal to 0.80 percent of Cu and Ni, less than or equal to 0.40 percent of Ceq and the balance of Fe and inevitable impurities. By the method, a continuous casting blank is used for producing high-performance Q345R steel plates with the thickness of 60 to 100mm, so that production cost is reduced, and the requirement of manufacturing containers with high parameter pressure is met; the low-C high-Mn component system is used for a component design, so that the requirement that the material Ceq is less than or equal to 0.40 percent is met; and the continuous casting blank is used for producing a high-performance Q345R super-thick plate, so that the method has a simple process, the process is easy to realize, and the plate can be produced by a common wide and thick plate factory.

Description

Technical field [0001] The invention belongs to iron and steel smelting technology, in particular to a production method of extra-thick steel plate. Background technique [0002] Extra-thick plates refer to steel plates with a thickness ≥ 60 mm. The production methods adopted in the prior art are summarized as follows: die-casting steel ingot and electroslag remelted steel ingot method, continuous casting slab thick slab method, welding compound slab method, vertical continuous casting machine to produce extra thick slab method. [0003] With the development of wide and thick plate production technology, the technology of using 260-300mm slabs to produce 60-100mm extra-thick plates has become very popular. At the same time, microalloying elements Nb, V, and Ti are added to the steel to improve the strength of the steel plate through grain refinement, mutagenesis precipitation during rolling, and precipitation of C(N)M during cooling, which has an impact on the production of...

AI Technical Summary

Problems solved by technology

The disadvantage of this invention is that the production of 45-70mm steel plates by TMCP process can only meet the general steel structure manufacturing needs of longitudinal impact toughness requirements, and the strength of steel plates after normalizing is low, so they cannot be used for normalizing, 1 / 2 and Production of extra-thick plates for pressure vessels with 1 / 4 thickness transverse impact toughness and Z-direction performance

[0007] A. The Q345R extra-thick plate with Ceq less than 0.40% is delivered in the normalizing state, and the strength is low and cannot meet the standard requirements;

[0008] B. It is difficult for the continuous casting slab to meet the requirement that the impact energy (transverse direction) of 1 / 4 and 1 / 2 thickness of the steel plate is greater than 100J at -20°C;

[0009] C. The rolling process is difficult to meet the requirements of Z35 in the thickness direction

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