CN-121976130-A - 1300 MPa-level low-density steel and hot rolling short-process preparation method thereof

CN121976130ACN 121976130 ACN121976130 ACN 121976130ACN-121976130-A

Abstract

The invention relates to 1300 MPa-level low-density steel and a hot rolling short-process preparation method thereof, belonging to the technical field of metal materials and metallurgy. The low-density steel prepared by the invention comprises the following chemical components in percentage by mass: 0.65 to 0.75 percent of C, 5.0 to 8.0 percent of Al, 17.5 to 20.0 percent of Mn, 0.40 to 0.50 percent of Si, 0.10 to 0.40 percent of Nb, 0.10 to 0.20 percent of Mo, 0.10 to 0.28 percent of V, 1.0 to 3.5 percent of Ni, 0.10 to 0.30 percent of Ti, 0.001 to 0.003 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 preparation method ensures that the density of the steel is reduced, simultaneously ensures that the steel forms a stable high-strength structure state in a hot rolled state, realizes the coordinated matching of the strength and the plasticity of the steel plate, and simplifies the preparation flow of the steel plate.

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. A1300 MPa grade low-density steel is characterized by comprising the following chemical components in percentage by mass: C 0.65%～0.75%,Al 5.0%～8.0%,Mn 17.5%～20.0%,Si 0.40%～0.50%,Nb 0.10%～0.40%,Mo 0.10%～0.20%,V 0.10%～0.28%,Ni 1.0%～3.5%,Ti 0.10%～0.30%,B 0.001%～0.003%,P≤0.008%,S≤0.020%, The balance being Fe and unavoidable impurities.
2. The 1300 MPa-grade low-density steel according to claim 1, wherein the 1300 MPa-grade low-density steel has a yield strength of 1080 MPa-1122 MPa, a tensile strength of 1300 MPa-1330 MPa and an elongation of 20% -26% in a hot rolled state.
3. The 1300 MPa-grade low-density steel according to claim 1, wherein the thickness of the finished product of the 1300 MPa-grade low-density steel is 5 mm-10 mm.
4. A hot rolling short-process preparation method of 1300 MPa-grade low-density steel according to any one of claims 1 to 3, characterized by comprising the steps of: (1) Smelting in a vacuum smelting furnace according to set components to obtain molten metal, pouring the molten metal into a casting mold, and cooling to obtain an ingot; (2) Heating the cast ingot, preserving heat, and then carrying out hot rolling, wherein the hot rolling process comprises a rough rolling stage and a finish rolling stage, and the hot rolling is carried out to finish the forming of the steel plate under the condition of ensuring the accumulated rolling reduction; (3) And cooling the steel plate after the hot rolling is finished, and directly obtaining the 1300 MPa-level low-density steel.
5. The method for preparing 1300 MPa-grade low-density steel by hot rolling in a short process, which is characterized in that the thickness of the cast ingot obtained in the step (1) is 120-180 mm.
6. The method for preparing 1300MPa grade low-density steel by hot rolling short flow according to claim 4, wherein the heating rate of the cast ingot in the step (2) is 5-15 ℃ per minute, the cast ingot is discharged after being kept in a heating furnace for 60-120 min, and the tapping temperature is 1050-1150 ℃.
7. The method for preparing 1300MPa grade low-density steel by hot rolling short process according to claim 4, wherein the rough rolling stage in step (2) is used for introducing larger deformation, a 4-6-pass large reduction rolling mode is adopted, the single-pass reduction rate in the rough rolling stage is not less than 15%, the thickness of a rough rolled intermediate billet is 50-70 mm, the 6-10-pass rolling mode is adopted in the finish rolling stage, the single-pass reduction rate is 15-35%, and the accumulated reduction rate in the finish rolling stage is 70-90%.
8. The method for preparing 1300MPa grade low-density steel by hot rolling short-process according to claim 4, wherein the rough rolling and the finish rolling are carried out within a temperature range suitable for thermal deformation, the initial rolling temperature of the rough rolling is 1040-1060 ℃, the initial rolling temperature of the finish rolling is 850-900 ℃, and the final rolling temperature of the finish rolling is 800-850 ℃.
9. The method for preparing 1300MPa grade low-density steel by hot rolling short flow according to claim 4, wherein the cooling in the step (3) is cooled to room temperature by adopting a water cooling mode, the initial cooling temperature is 760-810 ℃, and the cooling is not performed in a sectional mode or a path control mode.

Description

1300 MPa-level low-density steel and hot rolling short-process preparation method thereof Technical Field The invention belongs to the technical field of metal materials and metallurgy, and particularly relates to 1300 MPa-level low-density steel and a hot rolling short-flow preparation method thereof. Background With the rapid development of modern industry, the problems of energy consumption and environmental pollution are increasingly prominent. The steel material is still one of the most important structural materials in automobiles and transportation equipment because of stable resource foundation, mature process and controllable cost. Related researches show that in transportation equipment such as automobiles, the mass of a structural member can be reduced by 10% every time, the energy consumption can be effectively reduced by about 6% -8% and the emission can be reduced by about 5% -6%. Therefore, the realization of the weight reduction of the bearing member on the premise of ensuring the structural safety and the service reliability has become an important development direction in the fields of automobiles and transportation equipment. The low-density steel realizes the cooperative regulation and control of density reduction and mechanical property improvement by introducing alloy design into a steel material system, and has good application potential in the field of lightweight structural members. The low density steel helps to reduce component mass while maintaining the high strength advantage over conventional high strength steels, and is particularly useful for high strength bearings, shields and safety related structural components in automobiles and transportation equipment. However, with the continuous improvement of the strength grade, the preparation of the existing high-strength low-density steel often depends on complex smelting control, multi-step rolling, and subsequent heat treatment procedures such as normalizing, quenching or tempering, so that the preparation process is tedious, the production efficiency is reduced, the manufacturing cost is increased, and the popularization and the application of the high-strength low-density steel in the engineering field are restricted. For example, the invention patent with publication number CN118600329A discloses a Fe-Mn-Al-C series light high-strength steel and a preparation method thereof, wherein the steel comprises the following chemical components, by mass, 0.9% -1.2% of C, 8% -10% of Al, 27% -30% of Mn, 2.5% -3.5% of Ni, and the balance of Fe and unavoidable impurities. The patent adopts a laser selective melting (SLM) additive manufacturing technology to prepare the light high-strength steel, and the yield strength of the light high-strength steel can reach 850 MPa and the tensile strength of the light high-strength steel can reach 1100 MPa. Because the method depends on an additive manufacturing process, and the strength grade of the obtained steel is limited, the comprehensive requirements of the high-strength structural member on mechanical properties and industrial preparation efficiency are difficult to meet. The invention patent with publication number CN118272728A discloses a double-heterostructure high-strength plastic low-density steel and a preparation method thereof, wherein the steel comprises, by mass, 0.7% -1.2% of C, 8% -14% of Al, 14% -35% of Mn, 3% -7% of Ni, 0% -3% of V, nb, ti, mo respectively, and the balance of Fe and unavoidable impurities. The low-density steel is prepared through a plurality of procedures such as smelting, hot rolling, cold rolling, annealing, subsequent cooling and the like, the yield strength is 800-1200 MPa, the tensile strength is 1100-1400 MPa, and the elongation is 30-50%. Although the method can obtain higher strength and plasticity, the preparation process is complex, the process steps are more, the requirements on production equipment and process control are higher, and the method is unfavorable for large-scale engineering application. In addition, the invention patent with publication number CN114875318A discloses a low-density high-strength steel reinforced by dispersion delta phase and a manufacturing method thereof, wherein the steel comprises the following chemical components, by mass, 1.09% -1.14% of C, 11.40% -11.90% of Al, 29% -33% of Mn, and alloy elements such as Cr, ti, rare earth elements and N. The low-density steel plate is prepared by the processes of smelting and casting, temperature-controlled rolling, quenching and solid solution, and the like, and has yield strength exceeding 8239 MPa, tensile strength of about 985 MPa and elongation exceeding 39%. Although the steel plate has higher plasticity, the carbon and manganese contents are higher, and a heat treatment step is introduced in the process, so that the control of welding performance and the simplification of the process flow are not facilitated. In view of the above, in the background of the continuous improvemen