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CN-121976129-A - High-manganese high-aluminum low-density ultrahigh-strength steel plate and short-process preparation method thereof

CN121976129ACN 121976129 ACN121976129 ACN 121976129ACN-121976129-A

Abstract

The invention relates to a high-manganese high-aluminum low-density ultrahigh-strength steel plate and a short-process preparation method thereof, belonging to the technical field of metal materials and metallurgy. The steel plate comprises the following chemical components in percentage by mass: 0.80 to 1.05 percent of C, 8.0 to 10.5 percent of Al, 21.0 to 23.5 percent of Mn, 0.65 to 0.75 percent of Si, 0.25 to 0.40 percent of Nb, 0.40 to 0.65 percent of Mo, 0.40 to 0.50 percent of V, 0.002 to 0.004 percent of B, less than or equal to 0.008 percent of P, less than or equal to 0.020 percent of S, and the balance of Fe and unavoidable impurities. The thickness of the ultra-high strength steel plate prepared by the invention is 4-8 mm, the yield strength is 1340-1380 MPa, the tensile strength is 1400-1490 MPa, and the elongation is 16.8-18.4%.

Inventors

  • WU ZHIQIANG
  • SUN JIANHAO
  • XU GUILI
  • LIANG LIANG
  • LIU XUHUI
  • CHEN KUI
  • LIU NING
  • WEN CHANGFEI
  • WANG JIANHUA

Assignees

  • 湖南科技大学
  • 湖南华菱涟源钢铁有限公司

Dates

Publication Date
20260505
Application Date
20260209

Claims (9)

  1. 1. The high-manganese high-aluminum low-density ultrahigh-strength steel plate is characterized by comprising the following chemical components in percentage by mass, wherein the balance of the steel plate is ：C 0.80%～1.05%,Al 8.0%～10.5%,Mn 21.0%～23.5%,Si 0.65%～0.75%,Nb 0.25%～0.40%,Mo 0.40%～0.65%,V 0.40%～0.50%,B 0.002%～0.004%,P≤0.008%,S≤0.020%, of Fe and unavoidable impurities.
  2. 2. The high-manganese high-aluminum low-density ultra-high strength steel sheet according to claim 1, wherein the yield strength of the high-manganese high-aluminum low-density ultra-high strength steel sheet in a hot rolled state is 1340-1380 mpa, the tensile strength is 1400-1490 mpa, and the elongation is 16.8-18.4%.
  3. 3. The high-manganese high-aluminum low-density ultrahigh-strength steel plate according to claim 1, wherein the thickness of a finished product of the high-manganese high-aluminum low-density ultrahigh-strength steel plate is 4 mm-8 mm.
  4. 4. A short-process preparation method of the high-manganese high-aluminum low-density ultrahigh-strength steel plate according to any one of claims 1 to 3 is characterized by comprising the steps of carrying out vacuum smelting and casting according to chemical composition proportions to obtain an ingot, heating and preserving the ingot, carrying out hot rolling by adopting a rough rolling and finish rolling two-stage rolling mode, and carrying out controlled cooling on the finish rolled steel plate after finish rolling to obtain the hot-rolled high-manganese high-aluminum low-density ultrahigh-strength steel plate.
  5. 5. The short-process preparation method of the high-manganese high-aluminum low-density ultrahigh-strength steel plate, which is characterized by comprising the steps of vacuum smelting and casting, wherein the prepared raw materials are heated and melted to obtain metal liquid, and the metal liquid is poured into a casting mold and cooled to obtain an ingot with the thickness of 120-160 mm.
  6. 6. The short-process preparation method of the high-manganese high-aluminum low-density ultrahigh-strength steel plate, which is disclosed by claim 4, is characterized in that the steps of heating and preserving heat of the cast ingot are that the cast ingot is placed in a soaking pit for heating, the heating rate is 10 ℃ per minute, the cast ingot is discharged from the pit after preserving heat for 0.5min per mm in the heating pit, and the tapping temperature is 1100-1150 ℃.
  7. 7. The short-process preparation method of the high-manganese high-aluminum low-density ultra-high strength steel plate is characterized in that the initial rolling temperature of rough rolling is 1040-1060 ℃, the initial rolling temperature of finish rolling is 850-900 ℃, the final rolling temperature is 800-850 ℃, and the initial cooling temperature after finishing finish rolling is 760-810 ℃.
  8. 8. The short-process preparation method of the high-manganese high-aluminum low-density ultrahigh-strength steel plate is characterized in that the rough rolling adopts a 4-6-pass high-reduction rolling mode, the final 3-pass single-pass reduction rate is not lower than 20%, the thickness of an obtained intermediate blank is 50-70 mm, the finish rolling adopts an 8-12-pass rolling mode, the single-pass reduction rate is 16-35%, and the accumulated reduction rate is 80-93%.
  9. 9. The method for preparing a high-manganese high-aluminum low-density ultra-high strength steel sheet according to claim 4, wherein the controlled cooling process is performed on the finish-rolled steel sheet, and the finish-rolled steel sheet is cooled to room temperature by adopting a laminar cooling mode.

Description

High-manganese high-aluminum low-density ultrahigh-strength steel plate and short-process preparation method thereof Technical Field The invention belongs to the technical field of metal materials and metallurgy, and particularly relates to a high-manganese high-aluminum low-density ultrahigh-strength steel plate and a short-process preparation method thereof. Background With the rapid development of the fields of transportation, high-end equipment manufacturing and the like, the structural material has higher requirements on light weight and safety performance. The steel is one of the most widely used structural materials, and the density level and strength level of the steel directly influence the weight reduction effect and service reliability of equipment. On the premise of meeting the requirements of bearing and protective performance, the lightweight design of the steel plate structure is realized by reducing the material density and further improving the strength level, and the lightweight design becomes an important development direction of advanced steel materials. In recent years, high manganese high aluminum low density steel has received attention because of its high strength potential while reducing the material density. However, existing high manganese high aluminum low density steels often rely on higher alloy contents or complex machining and heat treatment processes in further increasing strength levels. Typical preparation routes generally include procedures such as solution treatment after hot rolling, cold rolling, multi-stage heat treatment, etc., resulting in lengthy preparation procedures, increased energy consumption, and adverse cost control and engineering applications. The invention patent with publication number CN108396244A discloses a cold-rolled medium-manganese high-aluminum low-density steel and a preparation method thereof, wherein C is 1.20% -1.30%, al is 9.5% -10%, mn is 10.7% -11.3%, P is less than or equal to 0.005%, S is less than or equal to 0.003%, and the balance is Fe and unavoidable impurities. The yield strength of the invention is 1170-1230 MPa, the tensile strength is 1280-1320 MPa, and the elongation is 16-17%. The preparation method of the invention comprises hot rolling, solid solution, cold rolling and annealing, is complex, is unfavorable for controlling the cost, has higher C content in the components, and is unfavorable for post-processing. The invention patent with publication number of CN113025794A is a method for improving the strength of Fe-Mn-Al-C series low-density steel, wherein C is 0.8-1.6%, al is 5-10%, mn is 15-30%, cr is less than or equal to 5%, mo is less than or equal to 3%, nb is less than or equal to 0.2%, ti is less than or equal to 0.5%, si is less than or equal to 2%, B is less than or equal to 0.6%, and the balance is Fe and unavoidable impurities. The yield strength of the invention is 1370-1900 MPa, and the elongation is more than or equal to 8%. The strength of the low-density steel is improved through ageing treatment after hot rolling, but the components of the low-density steel have higher noble metals such as Cr, mo and the like, so that the preparation cost is greatly improved. In addition, the invention patent with publication number CN117107168A discloses an ultra-high strength plastic product low-density steel plate and a preparation method thereof, wherein the yield strength is 1170 MPa-1230 MPa, the tensile strength is 1280 MPa-1320 MPa, and the elongation is more than or equal to 30.2%. The preparation method comprises hot rolling, solid solution, warm rolling, annealing, deep cooling and tempering treatment, and the preparation method is complex in preparation process and low in production efficiency although the invention obtains high strength. In summary, when the existing high-manganese high-aluminum low-density steel realizes ultrahigh strength, the problems of complex preparation process, high dependency on heat treatment procedures, limited engineering application and the like generally exist. Therefore, how to stably obtain the ultra-high strength steel plate through a short-flow preparation process while ensuring the low-density characteristic of the material and taking into account the production efficiency and the cost control is still a technical problem to be solved in the field. Disclosure of Invention The invention aims to provide a high-manganese high-aluminum low-density ultrahigh-strength steel plate and a short-flow preparation method thereof, which realize that the low-density steel plate stably obtains 1400 MPa-level strength level and good plastic matching in a hot-rolled state under the condition of not depending on solid solution, cold rolling or multi-stage heat treatment procedures by reasonable alloy component design and cooperative control of hot rolling process parameters, thereby meeting the comprehensive requirements of high-strength bearing and protection structural members in automobiles