160mm ultra-thick plate produced under low compression ratio condition and production method of 160mm ultra-thick plate

Abstract

The invention discloses a 160mm ultra-thick plate produced under a low compression ratio condition and a production method of the 160mm ultra-thick plate. The production method comprises the followingsteps: implementing molten steel rotary furnace smelting, preparing a continuous casting blank by using an LF+RH (Ladle Furnace+Ruhrstahl-Heraeus) refining process, implementing a heating process, and further implementing a rolling process of a period and an on-line swinging type cooling and thermal treatment process, thereby obtaining the ultra-thick plate, wherein the ultra-thick plate consistsof elements of C, Si, Mn, P, S, Nb, V, Ti, Ni, Alt and Fe, and inevitable impurities. The ultra-thick plate produced by using the production method disclosed by the invention is excellent in comprehensive mechanical property, the yield strength of the ultra-thick plate is 313-335MPa, the tensile strength of the ultra-thick plate is 496-516MPa, the elongation rate of the ultra-thick plate is 29-31.5%, the longitudinal impact power at minus 20 DEG C is greater than or equal to 161J, requirements of the standard GB / T 1581-2008 can be met, the cross section shrinkage rate in a thickness directionmeets requirements of Z35 in the standard GB / T 5313-2010, and results of flaw detection based on the standard GB / T 2970-2004 show that the real article quality of the ultra-thick plate meets the requirements of a grade II.

Description

technical field [0001] The invention relates to the technical field of metallurgy, in particular to a 160mm thick Q345D extra-thick plate produced under low compression ratio conditions and a production method thereof. Background technique [0002] With the increase of my country's infrastructure facilities and construction machinery projects, the demand for extra-thick plates over 100mm is increasing. For extra-thick plates over 100mm, not only must good internal quality, but also excellent mechanical properties, welding To meet the needs of the market, the billets for producing extra-thick plates include forging billets, steel ingots, composite billets, and continuous casting billets. However, the production of extra-thick plates using these billets has the limitations of long process flow and low yield. [0003] 160mm extra-thick plate, as an excellent structural part of engineering projects in extra-thick plates over 100mm, has a huge demand in extra-thick plates. It must...

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Problems solved by technology

[0002] With the increase of my country's infrastructure facilities and construction machinery projects, the demand for extra-thick plates over 100mm is increasing. For extra-thick plates over 100mm, not only must good internal quality, but also excellent mechanical properties, welding To meet the needs of the market, currently the blanks for producing extra-thick plates include forging billets, steel ingots, composite billets, and continuous casting billets, but the use of these billets to produce extra-thick plates has the limitations of long process flow and low yield

[0003] 160mm extra-thick plate, as an excellent structural part of engineering projects in extra-thick plates over 100mm, has a huge demand in extra-thick plates. It must have: ① high purity; ② high strength and toughness, Yield strength ≥ 275MPa, tensile strength 450-600MPa, longitudinal impact energy ≥ 27J at -20°C at 1 / 4 of the plate thickness; ③ good Z-direction performance; boards meet these performance requirements, the corresponding production costs are too high

[0004] The Chinese patent authorized in 2012 (the authorized announcement number is CN 102061373B) announced "a heat treatment process for improving the mechanical properties of high-strength extra-thick plates". Air-cooling for normalizing can improve the strength, plasticity and low-temperature brittleness of extra-thick plates, but this increases the complexity of the equipment. method is restricted

[0005] There are also special-heavy plate manufacturers in China that use 370mm-450mm continuous casting slabs to produce 160mm-thick extra-heavy plates, but the production process is two-fired or two-stage controlled rolling, the compression ratio is between 2.3 and 2.8, and then normalized furnace heat treatment , after being water-cooled or air-cooled, it increases the difficulty of continuous casting and the cost of subsequent heating and rolling. Such a production process is relatively low in production efficiency and cannot meet market demand

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