Middle and low carbon bainite high-strength high-ductility steel and manufacturing method thereof

Abstract

The invention discloses a medium-low bainite steel with high strength and high toughness and a manufacture method thereof. The manufacture method comprises the following step of: (1) the bainite steel containing, by weight percentage, C 0.12 to 0.35, Mn 0.80 to 2.6, Si 0.80 to 2.0, Cr 0.5 to 1.5, Mo 0.1 to 0.5, V 0.05 to 0.2, Nb 0.01 to 0.2, B not larger than 0.05, and Fe and non-surface impurityallowance; (2) smelting in a vacuum induction furnace, adjusting the components according to the range of the chemical components and electrically pouring an electrode; (3) carrying out electroslag remelting to remelt the electrode to a steel ingot, demolding, annealing in a annealing furnace at the temperature of 650 to 720 DEG C, keeping the temperature for 10 to 15 h, and air-cooling to 500 DEG C; and (4) forging with a start temperature not less than 1,100 DEG C and a final temperature of 850 to 950 DEG C, and air-cooling to 400 DEG C with a speed less than 50 DEG C / h. The product of the invention meets the requirement of high-strength and high-toughness steel and meets the requirement of an engineering material for manufacturing parts with high strength, high toughness and larger cross section.

Description

technical field [0001] The invention relates to high-strength bainite steel, in particular to a medium-low carbon bainite high-strength high-toughness steel and a manufacturing method thereof. Background technique [0002] The mechanical property requirements of 30CrMnSiA quenched and tempered steel (quenching + high temperature tempering): σb≥1080Mpa, σ0.2≥885Mpa, δ≥10%, φ≥45%, Ak≥39J, which are mostly used in the manufacture of structural parts and larger cross-sections The parts and components are also the steel type with the largest amount of military industry, such as: the key components of the rocket launcher. [0003] In practical application, it is found that some 30CrMnSiA modulated steel structural parts (or parts) must be welded in the open air, and cannot be heat treated after welding, which affects the performance of the steel. Therefore, it is necessary to develop a high-strength engineering material that can manufacture larger cross-section parts. Steel (its ...

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Problems solved by technology

[0005] The purpose of the present invention is to provide a medium-low carbon bainite high-strength high-toughness steel and its manufacturing method, which can manufacture parts and high-strength engineering materials with larger cross-sections, and solve the problem that existing non-modulated steels cannot manufacture larger cross-sections Technical problems of parts, product performance meets the requirements of high-strength and high-toughness steel (σb≥1350Mpa, σ0.2≥1180Mpa, δ≥12%, φ≥45%, Ak≥50J), to meet the requirements of manufacturing high strength, high toughness and large Engineering Material Requirements for Components of Sections