A kind of submicron austenite strengthened and toughened high-strength and tough thin steel plate and its preparation method

Abstract

A submicron austenite-strengthened high-strength and toughness thin steel plate and a preparation method thereof belong to the technical field of metallurgical materials. The sub-micron austenite-strengthened high-strength and toughness thin steel plate contains C? 0.19±0.02%, Mn? 1.5±0.2%, Al? 1.5±0.1%, Si? 0.3±0.02%, the balance is Fe, the tensile strength is 800~1100MPa, the yield strength is 450~520MPa, and the elongation rate is 42~53%. The preparation method is: (1) smelting and pouring into ingots; (2) heating to 1150±10℃ and holding for 1~3h, then hot rolling, cooling to 750±10℃ after hot rolling, holding for 0.5~1h, and then water cooling to normal temperature to obtain a hot-rolled steel plate; (3) perform cold rolling with a deformation of 40~55% to obtain a cold-rolled steel plate; (4) heat to 750~850°C at a rate of 80~120°C / s and keep it warm for 120 ~180s, then ultra-rapidly cooled to 420±10℃ at a rate of 80~100℃ / s, and kept warm for 4~6min. The thin steel plate prepared by the invention has very high strength and plasticity; it can be made by simply improving the existing process conditions and controlling parameters such as heat treatment and cooling.

Description

technical field [0001] The invention belongs to the technical field of metallurgical materials, and in particular relates to a submicron austenite strengthened and toughened high-strength and tough thin steel plate and a preparation method thereof. Background technique [0002] Steel is the most widely used material in aviation, nuclear energy, ships, petrochemical and other fields; high strength and high toughness are the main development direction of steel materials; the main problem encountered at present is how to improve its strength while maintaining Good toughness; at the same time, as my country's environmental problems, especially the threat of smog, are becoming more and more serious, people's health and normal life are seriously affected; reducing energy consumption and reducing pollution have become important issues that need to be solved urgently. By improving the strength of steel materials to ensure It is an effective measure to reduce carbon emissions by improv...

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Problems solved by technology

[0006] The new TRIP590 (Fe-1.4Mn-0.3Si-0.03Al-0.07C) steel prepared by Anshan Iron and Steel Co., Ltd. has been applied in Shanghai Huizhong and FAW Car Company. Its grain size is about 20 μm. When stretched at room temperature, its yield The strength is 450MPa, and the tensile strength is 860MPa (Development of Angang's new TRIP590 and TRIP780, Proceedings of the Seventh China Iron and Steel Annual Conference, Volume 4, 137-140 (2009)); although the material prepared by this method has a higher Yield strength and tensile strength, but its elongation is low, only 27%

The Fe-1.45Mn-1.22Si-0.03Al-0.12Ni-0.12CTRIP590 steel prepared by Jia Shujun et al. has an average grain size of about 5.7μm, a yield strength of 430MPa, a tensile strength of about 600MPa, and an elongation of 23%. (The effect of annealing temperature in the two-phase region on the microstructure and properties of TRIP590 steel, Journal of Materials Heat Treatment, Volume 34, 110-114 (2013)); its yield strength is similar to that of the present invention, but its tensile strength and plasticity are low, and it is relatively high for high strength And the application fields with high toughness requirements can not meet the requirements, and its high Si content is easy to cause surface defects in the industrial production process, making the subsequent galvanizing process difficult

The TRIP590 steel (J.Y.Huh, H.Huh, C.S.Lee, Effect of strain rate on plastic anisotropy of advanced high strength steel sheets, JInt. Plast., Vol.44, 23-46 (2013)) prepared by South Korea’s Huh et al. has a tensile strength of 850 MPa, but relatively low plasticity , the elongation rate is only 20%

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