High-strength and high-toughness steel plate with uniform performance and excellent performance in thickness direction and production method of high-strength and high-toughness steel plate

Abstract

The invention relates to a high strength and toughness steel plate with uniform performance and excellent performance in the thickness direction and a production method thereof, the steel plate comprises the following elements in percentage by mass: 0.102 to 0.139 percent of C, 0.05 to 0.12 percent of Si, 1.42 to 1.67 percent of Mn, less than or equal to 0.005 percent of P, less than or equal to 0.001 percent of S, 0.032 to 0.058 percent of Nb, 0.037 to 0.059 percent of V, 0.005 to 0.017 percent of Ti, 0.0007 to 0.0022 percent of Ca, 0.0007 to 0.0014 percent of Zr, (11 to 20) * 10 <-4 > percent of O, (10 to 22) * 10 <-4 > percent of N, less than or equal to 0.10 percent of Cu + Mo + Cr, less than or equal to 0.001 percent of As, less than or equal to 0.001 percent of Sn and the The thickness of the casting blank ranges from 360 mm to 380 mm, the center segregation of the casting blank is smaller than or equal to C1.0, the center porosity of the casting blank is smaller than or equal to 0.5, and the defects of cracks, bubbles, aluminum oxide and silicate inclusions and the like do not exist; the thickness of the finished steel plate ranges from 130 mm to 150 mm, ReL ranges from 473 MPa to 490 MPa, Rm ranges from 640 MPa to 658 MPa, A ranges from 33% to 35%, KV2 ranges from 278 J to 300 J at the temperature of-40 DEG C, Z in the thickness direction ranges from 72% to 75%, and the finished steel plate has high strength and toughness, excellent performance in the thickness direction and good performance uniformity.

Description

technical field [0001] The invention relates to the technical field of metal material manufacturing, in particular to a high-strength toughness steel plate with uniform performance and excellent thickness direction performance and a production method thereof. Background technique [0002] With the continuous progress of science and technology, the key projects of the national economy such as building structures, offshore platforms, pressure vessels, boiler manufacturing, water / nuclear power plants, shipbuilding, oil and gas pipelines, bridge structures, heavy machinery manufacturing, transportation and other major constructions The project is developing in the direction of large-scale and heavy-weight, and the technical requirements for steel materials are getting higher and higher, especially high-strength and ultra-thick steel plates ≥ 100mm, which not only require high strength and high plastic toughness, but also have excellent anti-layer Tear properties, welding propert...

AI Technical Summary

Problems solved by technology

Due to the lack of technical equipment and imperfect production technology, the high-strength steel plates ≥100mm produced in China cannot fully meet the technical requirements of large-scale construction projects, especially the lack of thickness direction performance, comprehensive performance uniformity and welding performance have restricted my country's special The development and progress of thick steel plates, even relying on forging or direct imports from abroad to meet domestic demand

[0003] Most of the domestic extra-thick steel plates use continuous casting slabs with a thickness ≥ 300mm. The greater the thickness of the slab section, the greater the internal and external temperature, which can easily cause the content of carbon, phosphorus, sulfur, manganese and other elements in the center of the slab to be higher than the surface of the slab. As a result, there is serious central component segregation in the slab, and during the cooling process of the finished steel plate, a hard martensite or bainite structure will be formed in the center of the steel plate, which seriously damages the performance uniformity and thickness direction performance of the steel plate

[0004] Before the present invention, Japanese Patent Application No. 6-198394 and No. 6-158222 patents can produce thick steel plates for building structures with excellent Z-direction performance. The disadvantage is that alloy elements such as Cu, Ni, and Mo are added during the composition design of the steel plates. The production cost is high, and the maximum thickness of the finished steel plate is only 75mm

[0005] The Chinese patent application with the application number 2009100481369.2 discloses an extra-thick steel plate for construction with excellent Z-direction performance and its production method. Excellent lamellar tear resistance, the disadvantage is that the steel plate products involved have no guarantee of impact toughness

The Chinese patent application number 202010804760.3 discloses a method for producing steel plates for welded structures with excellent Z-direction performance by using continuous casting slabs under the condition of small compression ratio. The invention has excellent Z-direction performance, but the patent adopts two-stage rolling Finishing + quenching + tempering, the manufacturing process cost is relatively high

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