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CN-120099410-B - 500 MPa-grade low-temperature-resistant high-manganese steel for non-magnetic steel bars and production method thereof

CN120099410BCN 120099410 BCN120099410 BCN 120099410BCN-120099410-B

Abstract

The invention provides 500 MPa-grade low-temperature-resistant high-manganese steel for non-magnetic steel bars and a production method thereof, wherein the balance of C0.25-0.45％,Si 0.15-0.35％,Mn 20-30％,P≤0.025％、S≤0.025％,V 0.05-0.15％,Nb 0.01-0.03％,Al 2.0-4.0％,N 0.01-0.03％, is Fe and unavoidable impurity elements. 4.6≤L=1.5× [ C ] +0.20× Mn+10.0xN is less than or equal to 6.5. Compared with the prior art, the invention is smelted according to the components, and the product has good toughness, plasticity and notch sensitivity resistance under the low-temperature environment of-165 ℃ by adopting the production method of the invention, wherein the mechanical property of the product at normal temperature meets the requirement. The steel bar has low production cost and feasible production process, and has good market prospect.

Inventors

  • YIN DEFU
  • DING LEI
  • YU LIANGQI
  • GUO ZHAN
  • YANG YINGDONG
  • ZHANG XIAORUI
  • JIANG TING
  • YUAN YUE
  • CHEN PENGFEI

Assignees

  • 马鞍山钢铁有限公司

Dates

Publication Date
20260508
Application Date
20250331

Claims (8)

  1. 1. The 500 MPa-level low-temperature-resistant high-manganese non-magnetic steel bar steel is characterized by comprising the following components in percentage by mass: C 0.25-0.45%,Si 0.15-0.35%,Mn 20-30%,P≤0.025%、S≤0.025%,V 0.05-0.15%,Nb 0.01-0.03%,Al 2.0-4.0%,N 0.01-0.03%, The balance of Fe and unavoidable impurity elements; the components of the 500 MPa-grade low-temperature-resistant high-manganese non-magnetic steel bar are also satisfied that L=1.5 x [ C ] +0.20 x [ Mn ] +10.0 x [ N ]. Ltoreq.6.5; The magnetic conductivity of the 500 MPa-grade low-temperature-resistant high-manganese non-magnetic steel bar steel is less than or equal to 1.05, the normal temperature performance R eL ≥500MPa、R m is more than or equal to 630MPa, A is more than or equal to 30%, the non-notch sample R eL ≥575MPa、A gt is more than or equal to 3%, the notch sample A gt is more than or equal to 1% and the notch sensitivity index NSR is more than or equal to 1.0 in a low-temperature environment of minus 165 ℃.
  2. 2. The 500 MPa-level low-temperature-resistant high-manganese non-magnetic steel bar steel according to claim 1, wherein the room-temperature structure of the 500 MPa-level low-temperature-resistant high-manganese non-magnetic steel bar steel is austenite.
  3. 3. A production method of the 500 MPa-grade low-temperature-resistant high-manganese non-magnetic steel bar steel as claimed in claim 1 or 2 is characterized by comprising the following process flows of smelting, LF furnace refining, RH vacuum treatment, continuous casting and rolling.
  4. 4. The method according to claim 3, wherein the smelting comprises an electric furnace or a converter, and the scrap steel and the ferromanganese alloy are added and then molten iron is added, wherein the molten iron accounts for 30-50%, the scrap steel and the ferromanganese alloy account for 70-50%, and the end point is that P is less than or equal to 0.010%, S is less than or equal to 0.010%, and the temperature is 1560-1610 ℃.
  5. 5. The production method according to claim 3, wherein the LF furnace refining is carried out by adding premelted refining slag 0.83-1.65kg/t and lime 6.67-8.33kg/t, TFe+MnO in slag is less than or equal to 1.0%, and the temperature of the LF furnace is 1565-1585 ℃.
  6. 6. The production method according to claim 3, wherein the RH vacuum degassing is performed at a molten steel temperature of 1525-1545 ℃ when the ladle is fed into the RH vacuum furnace, a vacuum holding time is more than or equal to 12 minutes in the early stage of vacuum, a vacuum holding time of more than or equal to 8 minutes is ensured after component adjustment in the vacuum stage, and a tapping RH vacuum furnace temperature of 1485-1505 ℃.
  7. 7. The method according to claim 3, wherein the continuous casting is performed by 150 square billet continuous casting, the whole-process protection casting is adopted, the casting temperature is 1450-1470 ℃, the cooling water flow of the crystallizer is 3000 liters/min, and the secondary cooling specific water flow is 0.8-1.2 liters/kg.
  8. 8. A production method according to claim 3, wherein the rolling is performed at 1150-1250 ℃, tapping temperature is 980-1080 ℃, three-stage water cooling is adopted after finish rolling, temperature is reduced by 150-250 ℃, and cooling bed temperature is 800-900 ℃.

Description

500 MPa-grade low-temperature-resistant high-manganese steel for non-magnetic steel bars and production method thereof Technical Field The invention belongs to the field of non-magnetic steel bar production, and particularly relates to 500 MPa-level low-temperature-resistant high-manganese steel for non-magnetic steel bars and a production method thereof. Background The non-magnetic steel has very wide application, and relates to the fields of electric power, rail transit, machinery, national defense and military industry, buildings and the like. The generator guard ring for the power industry has higher stress, so that nonmagnetic steel is needed to reduce magnetic leakage at the end part of a motor rotor, a guide mechanism, superconducting power generation, power transmission and energy storage equipment, a large-scale nuclear fusion device and the like of a magnetic suspension train for rail transit are needed, a large amount of nonmagnetic steel is needed to reduce the influence of a magnetic field on materials, the nonmagnetic steel is used for manufacturing a hull of a mine sweeping boat, a nonmagnetic engine, a structural material of a hidden submarine and the like in the national defense and military industry, and the nonmagnetic steel is used for avoiding the influence of the magnetic field in a magnetic shielding shelter for the building industry. In addition, nonmagnetic materials are also required for nonmagnetic bearings, petroleum drill collars, nonmagnetic dies, and the like. Therefore, the development of the low-cost high-performance non-magnetic steel material has important significance for civil and national defense military construction in China. The patent with publication number CN 117512308A published in 2 month 6 of 2024 discloses a non-magnetic steel bar and a preparation method thereof, wherein the non-magnetic steel bar comprises the following chemical components of C, si, mn, P, S, cr, V, O, N and Fe, wherein the content of C is 0.55-0.65%, the content of Si is 0.45-0.55%, the content of Mn is 18.0-18.5%, the content of P is less than or equal to 0.010%, the content of S is less than or equal to 0.010%, the content of Cr is 3.0-3.5%, the content of V is 1.70-1.73%, the content of O is 0-0.0010%, and the content of N is 0.0140-0.0150% by mass. The production method comprises the steps of heating a casting blank with set chemical components, rolling the heated casting blank, controlling the rolling technological parameters to obtain hot rolled steel, cooling the hot rolled steel, and controlling the cooling end temperature to obtain the non-magnetic steel bars. However, in the prior art, the content of C, V added is too high, which easily leads to brittle and hard reinforcing steel bars and influences the low-temperature performance. Therefore, it is necessary to provide a steel for non-magnetic steel bars having good strength and low temperature properties. Disclosure of Invention The invention aims to provide 500 MPa-level low-temperature-resistant high-manganese steel for non-magnetic steel bars and a production method thereof, wherein Mn, al and N are added, a steel making and rolling process is combined, an austenite structure is formed at room temperature, the requirement of magnetic conductivity less than or equal to 1.05 is met, nb and V are added, the precipitation strengthening effect is utilized, the mechanical property of the steel bars is improved, the normal-temperature performance reaches R eL≥500MPa、Rm to be more than or equal to 630MPa, A to be more than or equal to 30 percent, good low-temperature resistance performance is achieved, a notch sample R eL≥575MPa、Agt to be more than or equal to 3 percent, a notch sample A gt to be more than or equal to 1.0 is achieved in a low-temperature environment of-165 ℃, a notch sensitivity index NSR to be more than or equal to 1.0 (NSR=R m of the notch sample/R eL of the notch sample) and the technical requirement of the mechanical property of the non-magnetic steel bars in severe cold areas in winter can be met. The invention has the advantages of uncomplicated production process and suitability for large-scale industrial production, popularization and application. The specific technical scheme of the invention is as follows: A500 MPa-grade low-temperature-resistant high-manganese non-magnetic steel bar steel comprises the following components in percentage by mass: C 0.25-0.45％,Si 0.15-0.35％,Mn 20-30％,P≤0.025％、S≤0.025％,V0.05-0.15％,Nb 0.01-0.03％,Al 2.0-4.0％,N 0.01-0.03％, The balance of Fe and unavoidable impurity elements. The components of the 500 MPa-grade low-temperature-resistant high-manganese non-magnetic steel bar steel also meet that L=1.5× is more than or equal to 4.6% [C] +0.20 x [ Mn ] +10.0 and X [ N ] is less than or equal to 6.5. To improve the strength and non-magnetic properties of the steel. In the formula, each symbol represents the content of the corresponding chemical component by 100%. The room temperature