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CN-122013034-A - High-plasticity iron-based alloy and preparation method thereof

CN122013034ACN 122013034 ACN122013034 ACN 122013034ACN-122013034-A

Abstract

The invention provides a high-plasticity iron-based alloy and a preparation method thereof, and relates to the technical field of metal material processing. The method comprises the steps of preparing iron-based alloy molten steel containing manganese, silicon and aluminum, sequentially carrying out deoxidation pretreatment and rare earth microalloying treatment on the iron-based alloy molten steel before casting, stirring the deoxidation pretreatment and the rare earth microalloying treatment by using bottom blowing gas, casting the treated molten steel to obtain an ingot, and carrying out thermal mechanical processing and solution treatment on the ingot to obtain the high-plasticity iron-based alloy. The method is used for solving the problems that the prior art can not effectively regulate the shapes and the distribution of brittle and deformable inclusions in steel and can not eliminate stress concentration points from the source, so that the occurrence of strain localization is difficult to fundamentally inhibit.

Inventors

  • XU JINGMANG
  • WANG KAI
  • YANG JIAN
  • Bai Taoshuo
  • CUI KUNLIANG
  • ZHU HUI
  • GAO WENFENG
  • TANG TIEBING

Assignees

  • 西南交通大学
  • 中铁山桥集团有限公司

Dates

Publication Date
20260512
Application Date
20251210

Claims (10)

  1. 1. The high-plasticity iron-based alloy is characterized in that spherical rare earth composite inclusions with the size smaller than 1 mu m are dispersed and distributed in a microstructure of the high-plasticity iron-based alloy.
  2. 2. The high-plasticity iron-based alloy according to claim 1, wherein the high-plasticity iron-based alloy comprises, in weight percent, 1.0-1.3 of C, 13-15 of Mn, 0.3-1.0 of Si, 0.05-0.3 of y, the balance being Fe and unavoidable impurities, and the high-plasticity iron-based alloy has a true strain at break of greater than 80%.
  3. 3. A method for preparing a high plasticity iron-based alloy, comprising: preparing iron-based alloy molten steel containing manganese, silicon and aluminum; before casting, sequentially carrying out deoxidation pretreatment and rare earth microalloying treatment on the iron-based alloy molten steel, wherein bottom blowing gas stirring is adopted in the deoxidation pretreatment and the rare earth microalloying treatment; casting the treated molten steel to obtain an ingot; and carrying out thermomechanical processing and solution treatment on the cast ingot to obtain the high-plasticity iron-based alloy.
  4. 4. The method of producing a high plasticity iron-based alloy as defined in claim 3, wherein the composition of the iron-based alloy molten steel is, by weight, 1.0 to 1.3% C, 13 to 15% Mn, 0.3 to 1.0% Si, and the balance being Fe and unavoidable impurities.
  5. 5. The method of producing a high-plasticity iron-based alloy as set forth in claim 3, wherein deoxidizing pretreatment of the iron-based alloy molten steel comprises: Primary smelting of iron-base alloy molten steel in an electric arc furnace or an induction furnace, and tapping after the water content and the temperature of the iron-base alloy molten steel reach preset conditions; When the temperature of the iron-based alloy molten steel is not lower than 1500 ℃, bottom blowing nitrogen stirring is started, and meanwhile, silicon aluminum calcium barium wires are added into the iron-based alloy molten steel for deoxidization.
  6. 6. The method for preparing the high-plasticity iron-based alloy according to claim 5, wherein the silicon-aluminum-calcium-barium wire is added in the following manner: The silicon aluminum calcium barium wire is fed into the iron-based alloy molten steel at a speed of 1.0 m/s to 1.5 m/s by a wire feeding method.
  7. 7. The method of producing a high-plasticity iron-based alloy as set forth in claim 3, wherein the rare earth microalloying treatment of the iron-based alloy molten steel comprises: Adding yttrium-containing rare earth wires into deoxidized and pretreated iron-based alloy molten steel by a wire feeding method, and stirring by using bottom blowing gas in the process, wherein the feeding speed of the rare earth wires is 1.1-1.3 m/s.
  8. 8. The method for producing a high-plasticity iron-based alloy according to claim 7, wherein the rare earth wire is a cored wire, the outer layer is metallic iron, and yttrium alloy particles are filled in the inner layer.
  9. 9. The method of producing a high plasticity iron-based alloy as defined in claim 8, wherein the rare earth element is present in an amount of 20 to 25% by mass based on the total weight of the yttrium alloy.
  10. 10. A method of producing a high plasticity iron-based alloy as defined in claim 3, wherein the thermo-mechanical working and solution treatment of the ingot comprises: homogenizing the cast ingot at 1150-1250 ℃ and then hot rolling; the hot rolled sheet is kept at 1000-1100 ℃ and then quenched.

Description

High-plasticity iron-based alloy and preparation method thereof Technical Field The invention relates to the technical field of metal material processing, in particular to a high-plasticity iron-based alloy and a preparation method thereof. Background High strength iron-based alloys, such as high manganese austenitic steels, are important materials for making load bearing structural members, however, they generally have a tendency to localize early strain during room temperature elongation, resulting in insufficient uniform plastic deformation capability, fracture strain often being difficult to exceed 50%, greatly limiting the development of their tough potential and service life. In the prior art, the plasticity can be improved by adopting a multi-element alloying or complex thermo-mechanical process, but the methods often have the inherent defects of high alloy cost, narrow process window, difficult control, material strength sacrifice while the plasticity is improved. More fundamentally, the technology cannot effectively regulate the morphology and distribution of brittle and deformable inclusions in steel, and cannot eliminate stress concentration points from the source, so that the occurrence of strain localization is difficult to fundamentally inhibit. Disclosure of Invention The invention aims to provide a high-plasticity iron-based alloy and a preparation method thereof, so as to solve the problems. In order to achieve the above purpose, the technical scheme adopted by the invention is as follows: in a first aspect, the present invention provides a high-plasticity iron-based alloy in which spherical rare earth composite inclusions having a size of less than 1 μm are dispersed in a microstructure. Further, the high-plasticity iron-based alloy comprises, by weight, 1.0-1.3 parts of C, 13-15 parts of Mn, 0.3-1.0 parts of Si, 0.05-0.3 parts of Y, and the balance of Fe and unavoidable impurities, wherein the high-plasticity iron-based alloy has a true strain at break of more than 80%. On the other hand, the invention provides a preparation method of the high-plasticity iron-based alloy, which comprises the following steps: preparing iron-based alloy molten steel containing manganese, silicon and aluminum; before casting, sequentially carrying out deoxidation pretreatment and rare earth microalloying treatment on the iron-based alloy molten steel, wherein bottom blowing gas stirring is adopted in the deoxidation pretreatment and the rare earth microalloying treatment; casting the treated molten steel to obtain an ingot; and carrying out thermomechanical processing and solution treatment on the cast ingot to obtain the high-plasticity iron-based alloy. Further, the iron-based alloy molten steel comprises, by weight, 1.0-1.3% of C, 13-15% of Mn, 0.3-1.0% of Si, and the balance of Fe and unavoidable impurities. Further, the deoxidizing pretreatment of the iron-based alloy molten steel comprises the following steps: Primary smelting of iron-base alloy molten steel in an electric arc furnace or an induction furnace, and tapping after the water content and the temperature of the iron-base alloy molten steel reach preset conditions; When the temperature of the iron-based alloy molten steel is not lower than 1500 ℃, bottom blowing nitrogen stirring is started, and meanwhile, silicon aluminum calcium barium wires are added into the iron-based alloy molten steel for deoxidization. Further, the silicon-aluminum-calcium-barium filament is added in the following manner: The silicon aluminum calcium barium wire is fed into the iron-based alloy molten steel at a speed of 1.0 m/s to 1.5 m/s by a wire feeding method. Further, the rare earth micro-alloying treatment is carried out on the iron-based alloy molten steel, and the method comprises the following steps: Adding yttrium-containing rare earth wires into deoxidized and pretreated iron-based alloy molten steel by a wire feeding method, and stirring by using bottom blowing gas in the process, wherein the feeding speed of the rare earth wires is 1.1-1.3 m/s. Further, the rare earth wire is a cored wire, the outer layer is metal iron, and yttrium alloy particles are filled in the rare earth wire. Further, the rare earth element is present in an amount of 20% to 25% by mass based on the total weight of the yttrium alloy. Further, the thermo-mechanical processing and solution treatment of the ingot comprises: homogenizing the cast ingot at 1150-1250 ℃ and then hot rolling; the hot rolled sheet is kept at 1000-1100 ℃ and then quenched. The beneficial effects of the invention are as follows: The invention eliminates stress concentration points at the grain boundary by converting coarse and sharp inclusions which are concentrated at the grain boundary into fine and spherical rare earth composite inclusions which are dispersed and distributed in the grain boundary, reduces migration resistance of the grain boundary, ensures that adjacent grains can be better coordinated when