Middle and high temperature super-thick steel plate with excellent radiation resistance and manufacturing method thereof

Abstract

The invention discloses a middle and high temperature super-thick steel plate with excellent radiation resistance and a manufacturing method thereof. A component system of medium-carbon medium-manganese high-nitrogen low alloy steel is adopted as a basis; the acid soluble Als content and the ratio range of Als / N are properly controlled; the (Mn / C) ratio is controlled between 8 and 15; compound strengthening of (Ni+Cr+Mo) and calcium treatment are performed and the ratio of Ca / S is between 1.00 and 3.00; controlled rolling and subsequent heat treatment process are optimized; and excellent strength matching, exhaustion creep resistance, tempered brittleness resistance, and welding manufacturability are obtained, in particular, the steel plate has good neutron radiation brittleness resistance and a welding joint has good exhaustion creep resistance, so the steel plate is particularly suitable to be used as special heat-resistant pressure container body. The middle and high temperature super-thick steel plate with the excellent radiation resistance has the advantages of reducing the manufacturing cost of the steel plate, shortening the manufacturing cycle of the steel plate, and reducing the production organization difficulty of the steel plate; and more importantly, the welding manufacturability of the super-thick steel plate is improved, the manufacturing cost of user components is saved, the manufacturing time of the user components is shortened, and huge values are created for users.

Description

technical field [0001] The present invention relates to a medium-high-temperature extra-thick steel plate and a manufacturing method thereof, in particular to a medium-high-temperature extra-thick steel plate with room temperature tensile strength ≥ 570 MPa and 350°C tensile strength ≥ 530 MPa for a special heat-resistant pressure vessel shell with excellent radiation resistance and methods of manufacture thereof. Background technique [0002] The extra-thick steel plate for special heat-resistant container shell is a medium-high temperature structure that requires comprehensive mechanical properties (strength-toughness matching, strong-plasticity matching and yield strength ratio), welding performance, medium-high temperature performance, especially resistance to neutron radiation embrittlement. It is used to make the carcass, which is the key part of the special heat-resistant pressure vessel; during the service process of the special heat-resistant pressure vessel, the ca...

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Problems solved by technology

[0003] Steels for traditional medium and high temperature heat-resistant pressure vessels generally use steels containing 0.3-1.0% Mo, Cr-Mo series steels, and Mn-Ni-Mo steels, such as (159-160 "Huixishan Commemorative Technical Lecture", P 147-P164; 86-87 "Returning to Xishan Commemorative Technical Lecture", P259-P312)", it is inevitable to add a large amount of precious alloy elements such as Cu, Cr, Mo, Ni to these steel plates; this not only leads to increased manufacturing costs and increased manufacturing difficulty ( Steel plates containing Ni, Cr, Mo, and Cu, especially steel plates with high Cu, Ni, and Cr contents, have poor surface quality of cast slabs, and generally need to go off-line for surface cleaning, and sometimes surface coloring and penetrating PT inspections are required. billet surface grinding, warm cutting, etc.); and the alloy content of the steel plate is high, the carbon equivalent Ceq and welding cold crack sensitivity index Pcm are also high, especially when the C and Mn contents are high, not only Ceq and Pcm, but also the casting billet The degree of internal segregation has deteriorated significantly; this not only brings great difficulties to on-site welding, requires preheating before welding, and heat treatment after welding, the on-site welding environment deteriorates, welding efficiency decreases, and processing and manufacturing costs increase; Problems such as hydrogen corrosion, hydrogen-induced embrittlement, temper embrittlement, lamellar exfoliation of welded parts, creep embrittlement, especially neutron radiation embrittlement, etc. are prone to occur during use

At the same time, a large number of existing patent documents only explain how to achieve the strength and low-temperature toughness of the base steel plate, improve the welding performance of the steel plate, and obtain excellent HAZ toughness in the welding heat-affected zone. The structure in the central part is fine and uniform along the thickness direction of the steel plate to ensure the strength and toughness of the steel plate and the uniformity of strength and toughness along the thickness direction of the steel plate. Involved, such as Japanese patents No. 63-93845, No. 63-79921, No. 60-258410, No. 4-285119, No. 4-308035, No. 3-264614, No. 2-250917, No. 4-143246 and the United States US Patent4855106, US Patent5183198, US Patent4137104, etc.

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