Ultra-thick alloy steel sheet with excellent low-temperature toughness and preparation method thereof

Abstract

The invention relates to an ultra-thick alloy steel sheet with excellent low-temperature toughness. The ultra-thick alloy steel sheet is characterized in that a continuous casting blank subjected to annealing is used as a base blank to complete three-blank compounding; the thickness of the compounded blank is greater than 900mm; the procedures of vacuum electronic beam welding, compounded blank heating, rolling, and quenching-tempering heat treatment are performed, so as to produce the ultra-thick alloy steel sheet with thickness of 210mm for a pressure container. A manufacturing method of theultra-thick alloy steel sheet has the advantages that the process is short, the technology is simple, the finished rate is high, the cost is low, the production cycle is short, the efficiency is high, and the like. The mechanical properties of the produced ultra-thick alloy steel sheet can meet the requirements that the unit value of core transverse impact is greater than or equal to 200J; the percentage reduction of area along a thickness direction is greater than or equal to 60%; the ultrasonic flaw detection of the steel sheet can meet the highest level requirement of NB / T47013.3.

Description

technical field [0001] The invention belongs to the field of metal material processing, and particularly relates to an excellent low-temperature toughness extra-thick alloy steel plate and a manufacturing method thereof. Background technique [0002] At present, my country's scientific and technological strength is gradually increasing, and equipment in the fields of petroleum, chemical industry, and nuclear power is rapidly developing in the direction of large wall thickness, large size, and high performance. To more than 150mm or even more than 200mm. The difficulty of producing steel plates with a thickness of more than 200mm is that the thicker the steel plate, the worse the internal flaw detection performance and the worse the uniformity of structure and properties. At present, the production of steel plates with a thickness of more than 200mm is usually rolled by large die-cast ingots or electroslag ingots, or directly forged from ingots. However, large-scale die-cast...

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Problems solved by technology

[0005] CN104962814B "A kind of normalized high-strength toughness 150mm extra-thick plate and its production method" discloses a 150mm extra-thick steel plate with a thickness of only 150mm, which cannot meet the requirements of large pressure vessels

Its composition does not contain alloy elements such as Cr and Mo, so it is difficult to guarantee high-temperature performance, so it is not suitable for applications in petroleum, chemical and nuclear power industries that require high-temperature performance

[0006] CN102732674A "A Production Method of Large-Thickness Low-alloy High-Strength Structural Steel Plate", relates to a method for producing extra-thick high-strength low-alloy structural steel by using 640-960 electroslag remelting ingots, which has high cost and long production cycle

[0007] CN102409238B "A 42CrMo Alloy Structural Steel Extra-Thick Plate and Its Production Method", which relates to a production method for producing 80-150mm thick steel plates by using steel ingots. Because the steel ingots need to be removed from the risers and tails and other defective areas, the steel ingots are rolled The material yield is low, the production cost is high, and it is not suitable for mass production

[0010] 1. The production process is long and the process is complicated;

[0011] 2. Low yield, high cost, long production cycle and low efficiency;

[0012] 3. The product has small thickness, low alloy content, narrow application range, etc.

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