Good low-temperature high-toughness normalizing type high-strength pressure container steel plate and manufacturing method thereof

Abstract

The present invention discloses a good low-temperature high-toughness normalizing type high-strength pressure container steel plate, wherein the chemical components comprise, by weight, 0.10-0.22% of C, less than or equal to 0.40% of Si, 1,10-1.80% of Mn, less than or equal to 0.015% of P, less than or equal to 0.010% of S, less than or equal to 0.40% of Ni, less than or equal to 0.035% of Nb, less than or equal to 0.17% of V, 0.0070-0.0190% of N, 0-0.025% of Als, 0-0.018% of Ti, and the balance of Fe and unavoidable inclusion, wherein (V+Ti+Nb)/N is more than or equal to 3.5 and is less than or equal to 15, and (C+V+2Ti) is more than or equal to Ti+Nb/(3.5N) and is less than or equal to 5V/(C+V+Nb). The good low-temperature high-toughness normalizing type high-strength pressure container steel plate has the following characteristics that: the yield strength is more than or equal to 460 MPa, the tensile strength is 630-725 MPa, the elongation is more than or equal to 25%, the yield ratio is less than or equal to 0.85, the weldability is good, and the production cost is low.

Description

technical field [0001] The invention relates to the field of low-alloy steel manufacturing, in particular to a normalized high-strength pressure vessel steel plate with good low-temperature high toughness and a manufacturing method thereof. Background technique [0002] With the rapid development of my country's economy, the demand for pressure vessels shows a trend of high-parameter development. These pressure vessels have one of two characteristics: [0003] 1) The use of advanced technologies and processes, and the diversification and deterioration of raw materials make the service conditions of pressure vessels extreme, manifested as higher pressure and lower temperature; [0004] 2) In order to improve economic benefits, pressure vessels with extreme dimensions appear, which are characterized by larger diameters, thinner wall thicknesses, and greater lengths or heights. [0005] The yield strength of micro-alloyed high-strength low-alloy steel is 2 to 3 times that of h...

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Problems solved by technology

[0008] The Chinese invention patent with the publication number CN 95104993.3 discloses the chemical composition, manufacturing method and performance of a large spherical tank steel with yield strength ≥ 460MPa. It increases the production cost, does not mention its welding performance, and does not see its introduction to the metallographic structure of the finished steel plate

[0009] The Chinese invention patent with the publication number CN103233160A discloses a normalized high-strength steel plat

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