An ultra-high manganese austenitic wear-resistant steel, a preparation method and application thereof

Abstract

The application discloses a kind of ultra-high manganese austenitic wear-resistant steel and its preparation method and application, belong to wear-resistant steel technical field.The wear-resistant steel according to weight fraction, component includes C:0.3%‑0.35%, Si:0.11%‑0.22%, Mn:29%‑31%, P≤0.02%, S≤0.005%, Cr:0.1%‑1%, Nb:0.03%‑0.1%, Alt:0.01%‑0.1%, the balance is Fe and inevitable impurities, its preparation method includes heating, scale removal, rolling, accelerated cooling process, the steel is single-phase austenite structure, 0 ℃ under yield strength ≥300MPa, tensile strength ≥650MPa, elongation after break ≥60%, impact energy under-269 ℃ ≥100J, surface after wear hardness can be promoted from 200HBW to 400~500HBW, with excellent super low temperature toughness and wear resistance, the application does not need to add Ni, Mo, Cu and other noble metals, and secondary heat treatment process is saved, cost economy is outstanding, suitable for extremely cold region coal mine scraper conveyor, bulldozer, excavator and other equipment key wear parts.

Description

Technical Field

[0001] This invention relates to the field of steel production technology, and in particular to an ultra-high manganese austenitic wear-resistant steel, its preparation method, and its application. Background Technology

[0002] High-manganese steel exhibits high strength and good ductility under normal conditions. However, when subjected to severe impact or compression, the surface layer rapidly undergoes work hardening, resulting in a dramatic increase in hardness and the formation of an extremely wear-resistant surface, while the core retains excellent toughness to resist impact. Since its introduction, industrial applications have primarily focused on components subjected to high-stress wear, such as railway turnouts, track plates, and crusher jaw plates, offering a service life several times longer than ordinary steel and bringing significant economic benefits. During both World Wars, high-manganese steel was widely used in tank tracks, armor plates, and trenching machinery, demonstrating its reliability under extreme conditions. In recent years, with improvements in its composition, the wear resistance, strength, and ductility of high-manganese steel have been further enhanced, leading to its widespread application in mining, building materials, power generation, agricultural machinery, and metallurgy.

[0003] CN202411626042 discloses a wear-resistant steel with good low-temperature impact toughness, whose chemical element composition is C 0.2wt.%~0.3wt.%, Si 0.2wt.%~0.5wt.%, Mn 0.4wt.%~0.6wt.%, Cr 10wt.%~15wt.%, Mo 0.5wt.%~1wt.%, V 0.3wt.%~0.4wt.%, S≤0.015wt.%, P≤0.015wt.%. The production process of this steel requires secondary heat treatment.

[0004] CN118880184A discloses a low-density low-temperature steel with a chemical element composition of 20%–30% Mn, 0.5%–1.5% C, 5%–12% Al, and the balance being Fe, totaling 100%. This steel has a high Al content and requires secondary heat treatment.

[0005] CN119040753A discloses an austenitic-ferritic dual-phase lightweight low-temperature steel with the following chemical composition: C: 0.02–0.05%; Mn: 25.0–30.0%; Al: 6.0–7.0%; Ti: 0.01–0.05%; Nb: 0.01–0.05%; Mo: 0.02–0.08%; P≤0.010%; S≤0.006%; N≤0.005%; the remainder being iron and unavoidable impurities. This steel has a high Al content, and the billet needs to be forged to a thickness of 60–80 mm.

[0006] CN114107830A discloses a low-density wear-resistant steel for wide temperature range and its preparation method, belonging to the technical field of high-performance wear-resistant steel. The chemical composition is: C: 0.70-3.0%, Mn: 15-35%, Ni: 0-10%, Cu: 0-5%, Al: 5-13%, Cr: 0-10.0%, Ni: 0-10%, Ti: 0-5%, Mo: 0-2.0%, Nb: 0-2.0%, V: 0-2.0%, wherein the total amount of Ti, Nb, Mo, and V is not less than 0.5%; the balance is Fe and unavoidable impurities; and one or more of the following elements are added: Si: 0-0.60wt%, Cu: 0-0.50wt%, B: 0-0.005wt%, RE: 0-0.050wt%. The high carbon content in this steel reduces its toughness, and the high content of precious elements such as Cu, Cr, Ni, and Ti makes it uneconomical. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and provide an ultra-high manganese austenitic wear-resistant steel, its preparation method and application.

[0008] To solve the above technical problems, the technical solution of the present invention is as follows: An ultra-high manganese austenitic wear-resistant steel, by weight fraction, comprises C: 0.3%-0.35%, Si: 0.11%-0.22%, Mn: 29%-31%, P≤0.02%, S≤0.005%, Cr: 0.1%-1%, Nb: 0.03%-0.1%, Alt: 0.01%-0.1%, with the balance being Fe and unavoidable impurities.

[0009] A further preferred embodiment of the present invention comprises: C: 0.33%, Si: 0.17%, Mn: 30%, Cr: 0.5%, Nb: 0.07%, Alt: 0.06%, with the balance being Fe and unavoidable impurities.

[0010] A further preferred embodiment of the present invention comprises: C: 0.3%, Si: 0.11%, Mn: 29%, Cr: 0.1%, Nb: 0.03%, Alt: 0.01%, with the balance being Fe and unavoidable impurities.

[0011] A further preferred embodiment of the present invention comprises: C: 0.35%, Si: 0.22%, Mn: 31%, Cr: 1%, Nb: 0.1%, Alt: 0.1%, with the balance being Fe and unavoidable impurities.

[0012] A further preferred embodiment of the present invention includes a wear-resistant steel with a thickness of 12-50 mm, an austenitic microstructure, and a yield strength R at 0°C.p0.2 ≥300MPa, tensile strength R m ≥650MPa, elongation after fracture ≥60%, impact energy Akv≥100J at -269℃.

[0013] This invention provides a method for preparing ultra-high manganese austenitic wear-resistant steel, characterized by the following steps: (1) Heating: The billet heating temperature is 1100-1200℃, the total furnace time is 1.5-2.0min / mm×bill thickness, and the compression ratio of billet to finished steel plate is ≥5; (2) Remove scales; (3) Rolling: The initial rolling temperature of the billet is 1090-1180℃, and the final rolling temperature is 850-950℃; (4) Cooling: The rolled steel plate is cooled at an accelerated rate of 15-45℃ / s.

[0014] In a further preferred embodiment of the present invention, phosphorus removal is performed by using high-pressure water at a pressure of 22~24MPa to remove the iron oxide scale from the surface of the heated billet.

[0015] In a further preferred embodiment of the present invention, the rolled steel plate is subjected to accelerated cooling, with an inlet water temperature of 830-920℃, an outlet water temperature of 100-300℃, and a cooling rate of 15-45℃ / s.

[0016] This invention relates to the application of ultra-high manganese austenitic wear-resistant steel in the manufacture of key wear-prone components for coal mine scraper conveyors, bulldozers, excavators, mixers, or loaders.

[0017] The high-manganese steel composition system of this invention incorporates Nb as a key element. The main functions of Nb in the steel are as follows: (1) Refine grain size Nitrogen (Nb) combines with elements such as carbon and nitrogen in steel to form fine carbides and nitrides. These particles can hinder the growth of austenite grains, thus effectively refining the grains of high-manganese steel. The refined grains improve the strength and toughness of high-manganese steel, while also improving its machinability and wear resistance, and reducing crack initiation and propagation.

[0018] (2) Improve welding performance Nb can reduce the overheating sensitivity of high manganese steel, prevent overheating structures during welding, and reduce the generation of welding cracks.

[0019] The present invention preferably controls the Nb content to be 0.03%-0.1%, more preferably 0.07%.

[0020] Austenitic structures possess excellent strength, plasticity, and toughness, along with lower service temperatures. While adding high amounts of Ni can produce an austenitic structure, such as 316 austenitic stainless steel with 12% Ni content, the alloy cost is high. Mn can inhibit the transformation of austenite into martensite and can therefore be used as a substitute for Ni to obtain an austenitic structure.

[0021] Carbon (C) is an element that can significantly improve the stability of austenite, and its strong austenite-stabilizing effect helps suppress martensitic transformation. Simultaneously, carbon can also hinder dislocation movement, thereby increasing material strength. From the perspective of austenite stabilization, the addition of carbon can increase the stacking fault energy of austenite, promoting the formation of twins during strain rather than martensitic transformation. This strain-induced twinning mechanism helps to significantly improve the plasticity of the material. Therefore, in the ultra-low temperature steel of this invention, the carbon content is controlled at 0.30%–0.35%, more preferably 0.33%.

[0022] Manganese (Mn) is undoubtedly a core element. In high-manganese steel, Mn generally plays two roles: First, as an austenitizing stabilizer, Mn expands the austenite phase region, allowing high-manganese steel to achieve a single-phase austenite structure at room temperature. Second, Mn's influence on stacking fault energy is non-linear. The lowest stacking fault energy is achieved with an Mn content of 10-16%. However, as the Mn content increases (16-33%), the stacking fault energy increases. In addition, the addition of Mn also increases the solid solubility of carbon (C) in the steel. The C-Mn interaction also affects the deformation mechanism, allowing the stacking fault energy of austenite at -269℃ to be controlled at 18-40 mJ / m. 2 This results in the wear-resistant steel of the present invention exhibiting a Charpy impact absorption energy ≥100J at -269℃. In summary, increasing the Mn content not only improves strength and plasticity but also effectively enhances resistance to brittle fracture under low-temperature deformation. However, when the Mn content reaches 32-33%, the β-Mn phase begins to appear in the high-manganese steel microstructure. This is a brittle phase with a complex cubic structure and extremely poor toughness. Typically, the upper limit for Mn content in high-manganese steel is controlled at 31%. Therefore, the manganese content of the present invention is controlled at 29%-31%, preferably 30%. Although chromium (Cr) is a ferrite-forming element, it can lower the martensite transformation temperature, thereby enhancing the stability of austenite. However, excessively high chromium content can exacerbate carbide precipitation, adversely affecting toughness. Therefore, the present invention sets the chromium content at 0.1%–1%, more preferably 0.5%.

[0023] Regarding the selection of other elements, silicon (Si) can produce a certain solid solution strengthening effect, but its segregation at grain boundaries weakens grain boundary strength, increases intergranular brittleness, and reduces plasticity. Therefore, the silicon content is preferably controlled at 0.11%–0.22%. Aluminum (Al) is used as a deoxidizer during manufacturing and also helps improve the performance of welded joints, but excessive addition can easily form coarse precipitates, impairing toughness. Therefore, the aluminum content is preferably controlled at 0.01%–0.10%.

[0024] In order to obtain sufficient grain refinement and strain accumulation through thermomechanical rolling, and thus sufficient strength of the finished steel plate, a sufficient compression ratio is required in the selection of slab thickness, that is, the ratio of slab thickness (H) to finished steel plate thickness (h) (H / h). Therefore, the present invention controls the compression ratio to ≥5.

[0025] Because the thermal conductivity of the ultra-low temperature steel of this invention is only about one-third that of ordinary low-alloy steel, it is necessary to ensure that slabs of different thicknesses have sufficient furnace heating time to ensure complete austenitization. Therefore, this invention controls the furnace time at (1.5~2.0 min / mm) × H, where H is the slab thickness. For example, when the slab thickness is 240 mm, the furnace time is 360~480 min.

[0026] After being heated in a walking beam furnace, the slabs are removed from the furnace and then pass through a descaling box to remove iron oxide scale. High-pressure water at 22~24MPa is used to ensure the descaling effect.

[0027] After descaling in a descaling box, the slab is rolled at an initial rolling temperature of 1090~1180℃, with a relatively low final rolling temperature of 850~950℃. Thermomechanical rolling refines the austenite grains, accumulates sufficient strain, and improves the strength of the finished steel plate. Sufficient slab thickness is also beneficial for improving the thermomechanical rolling effect.

[0028] After rolling, the steel plate enters an ultra-fast cooling system for high-pressure water cooling. The inlet water temperature is 830~920℃, and the cooling rate is 15~45℃ / s to the outlet water temperature of 100~300℃. The purpose of accelerated cooling is twofold: firstly, to retain the accumulated thermomechanical rolling strain and improve the strength of the steel plate; and secondly, to inhibit carbide precipitation and improve the plasticity of the steel plate.

[0029] The ultra-high manganese austenitic wear-resistant steel described in this invention is used in the manufacture of key wear-prone parts of equipment such as coal mine scraper conveyors, bulldozers, excavators, mixers, and loaders. It is also used in important components where high wear resistance is required. Its application is preferably in operating conditions in extremely cold regions.

[0030] The beneficial effects of this invention are: This invention limits the Mn content to 29%~31%, which avoids the problem of β-Mn brittle phase appearing when the Mn content exceeds 32%. Furthermore, through the synergistic effect with C, the austenite stacking fault energy at -269℃ is controlled at 18~40 mJ / m², achieving a balance between toughness and wear resistance in ultra-low temperature environments. This makes it particularly suitable for mining machinery in extremely cold regions. Without adding precious metals such as Ni, Mo, and Cu, the precise addition of Nb (0.03%~0.1%) simultaneously achieves the dual effects of grain refinement and improved weldability. This invention employs a heating-descaling-rolling-accelerated cooling process, eliminating the need for secondary heat treatment and solving the problems of complex processes and high costs in existing technologies. Through the coordinated design of key process parameters, it ensures the stability of the austenitic structure and inhibits carbide precipitation, achieving a synergistic improvement in strength and plasticity. It does not contain precious metal elements such as Ni / Mo / Cu and has excellent wear resistance. The rolling process eliminates post-processing steps, making the manufacturing cost more economical. Attached Figure Description

[0031] Figure 1 The image shows the microstructure of the steel plate prepared in Example 1. Detailed Implementation

[0032] The technical solution of the present invention will be further described below with reference to the embodiments.

[0033] The testing of yield strength, tensile strength, elongation after fracture, and impact energy shall be conducted in accordance with GB / T228.1-2021 Metallic materials, tensile testing - Part 1: Test method at room temperature, GB / T228.3-2019 Metallic materials, tensile testing - Part 3: Test method at low temperature, GB / T228.4-2019 Metallic materials, tensile testing - Part 4: Test method in liquid helium, and GB / T229-2020 Metallic materials, Charpy pendulum impact test method. Example 1

[0034] A low-temperature resistant, ultra-high manganese austenitic wear-resistant steel has the following chemical composition by mass percentage: C: 0.33%, Si: 0.17%, Mn: 30%, Cr: 0.5%, Nb: 0.07%, Alt: 0.06%, with the balance being Fe and unavoidable impurities.

[0035] The above preparation method includes: (1) Heating: The billet is heated by a walking beam furnace with a thickness of 260 mm, a target temperature of 1150 °C, a total furnace time of 1.6 H, and a compression ratio of billet to finished steel plate ≥ 5. (2) Descaling: Use a descaling box to remove the iron oxide scale from the billet after heating and exiting the furnace, with a high-pressure water pressure of 23 MPa; (3) Rolling: initial rolling temperature 1112℃, final rolling temperature 910℃, rolled steel plate thickness 16mm; (4) Cooling: The rolled steel plate is cooled by ultra-fast cooling equipment with an inlet water temperature of 860℃, an outlet water temperature of 290℃, and a cooling rate of 30℃ / s.

[0036] The prepared steel plate has an austenitic microstructure, a room temperature yield strength of 346 MPa, a room temperature tensile strength of 746 Pa, a room temperature elongation after fracture of 67%, a -196℃ yield strength of 524 MPa, a -196℃ tensile strength of 1148 MPa, a -196℃ elongation after fracture of 52.5%, a -196℃ impact energy of 165 J, and a -269℃ impact energy of 140 J. Example 2

[0037] A low-temperature resistant, ultra-high manganese austenitic wear-resistant steel has the following chemical composition by mass percentage: C: 0.3%, Si: 0.11%, Mn: 29%, Cr: 0.1%, Nb: 0.03%, Alt: 0.01%, with the balance being Fe and unavoidable impurities.

[0038] The above preparation method includes: (1) Heating: The billet is heated by a walking beam furnace with a thickness of 260 mm, a target temperature of 1161 °C, a total furnace time of 1.65 H, and a compression ratio of billet to finished steel plate ≥ 5. (2) Descaling: Use a descaling box to remove the iron oxide scale from the billet after heating and exiting the furnace, with a high-pressure water pressure of 25 MPa; (3) Rolling: initial rolling temperature 1120℃, final rolling temperature 924℃, rolled steel plate thickness 16mm; (4) Cooling: The rolled steel plate is cooled by ultra-fast cooling equipment with an inlet water temperature of 870℃, an outlet water temperature of 270℃, and a cooling rate of 33℃ / s.

[0039] The prepared steel plate has an austenitic microstructure, a room temperature yield strength of 340 MPa, a room temperature tensile strength of 751 MPa, a room temperature elongation after fracture of 65%, a -196℃ yield strength of 512 MPa, a -196℃ tensile strength of 1135 MPa, a -269℃ elongation after fracture of 51.5%, a -196℃ impact energy of 160 J, and a -269℃ impact energy of 137 J. Example 3

[0040] A low-temperature resistant, ultra-high manganese austenitic wear-resistant steel has the following chemical composition by mass percentage: C: 0.35%, Si: 0.22%, Mn: 31%, Cr: 1%, Nb: 0.1%, Alt: 0.1%, with the balance being Fe and unavoidable impurities.

[0041] (1) Heating: The billet is heated by a walking beam furnace with a thickness of 260mm, a target temperature of 1160℃, a total furnace time of 1.6H, and a compression ratio of billet to finished steel plate ≥5; (2) Descaling: Use a descaling box to remove the iron oxide scale from the billet after heating and exiting the furnace, with a high-pressure water pressure of 23 MPa; (3) Rolling: initial rolling temperature 1121℃, final rolling temperature 921℃, rolled steel plate thickness 16mm; (4) Cooling: The rolled steel plate is cooled by ultra-fast cooling equipment. The water inlet temperature is 867℃, the water outlet temperature is 285℃, and the cooling rate is 31℃ / s.

[0042] The prepared steel plate has an austenitic microstructure, a room temperature yield strength of 351 MPa, a room temperature tensile strength of 755 MPa, a room temperature elongation after fracture of 62%, a -196℃ yield strength of 507 MPa, a -196℃ tensile strength of 1141 MPa, a -196℃ elongation after fracture of 52%, a -196℃ impact energy of 158 J, and a -269℃ impact energy of 132 J.

[0043] In addition to the above embodiments, the present invention may have other implementation methods; all technical solutions formed by equivalent substitution or equivalent transformation fall within the protection scope claimed by the present invention.

Claims

1. A high-manganese austenitic wear-resistant steel, characterized in that, By weight fraction, its composition includes C: 0.3%-0.35%, Si: 0.11%-0.22%, Mn: 29%-31%, P≤0.02%, S≤0.005%, Cr: 0.1%-1%, Nb: 0.03%-0.1%, Alt: 0.01%-0.1%, with the balance being Fe and unavoidable impurities.

2. The ultra-high manganese austenitic wear-resistant steel according to claim 1, characterized in that, Its composition includes C: 0.33%, Si: 0.17%, Mn: 30%, Cr: 0.5%, Nb: 0.07%, Alt: 0.06%, with the balance being Fe and unavoidable impurities.

3. The ultra-high manganese austenitic wear-resistant steel according to claim 1, characterized in that, Its composition includes C: 0.3%, Si: 0.11%, Mn: 29%, Cr: 0.1%, Nb: 0.03%, Alt: 0.01%, with the balance being Fe and unavoidable impurities.

4. The ultra-high manganese austenitic wear-resistant steel according to claim 1, characterized in that, Its composition includes C: 0.35%, Si: 0.22%, Mn: 31%, Cr: 1%, Nb: 0.1%, Alt: 0.1%, with the balance being Fe and unavoidable impurities.

5. The ultra-high manganese austenitic wear-resistant steel according to claim 1, characterized in that: This wear-resistant steel has a thickness of 12-50mm, a microstructure of austenitic structure, and a yield strength R at 0℃. p0.2 ≥300MPa, tensile strength R m ≥650MPa, elongation after fracture ≥60%, impact energy Akv≥100J at -269℃.

6. The method for preparing ultra-high manganese austenitic wear-resistant steel according to any one of claims 1-4, characterized in that: Specifically, the following steps are included: (1) Heating: The billet heating temperature is 1100-1200℃, the total furnace time is 1.5-2.0min / mm×bill thickness, and the compression ratio of billet to finished steel plate is ≥5; (2) Remove scales; (3) Rolling: The initial rolling temperature of the billet is 1090-1180℃, and the final rolling temperature is 850-950℃; (4) Cooling: The rolled steel plate is cooled at an accelerated rate of 15-45℃ / s.

7. The method for preparing ultra-high manganese austenitic wear-resistant steel according to claim 6, characterized in that: Phosphorus removal is performed by using high-pressure water at a pressure of 22~24MPa to remove the iron oxide scale from the surface of the heated billet.

8. The method for preparing ultra-high manganese austenitic wear-resistant steel according to claim 6, characterized in that: The rolled steel plate is subjected to accelerated cooling, with an inlet water temperature of 830-920℃, an outlet water temperature of 100-300℃, and a cooling rate of 15-45℃ / s.

9. The use of the ultra-high manganese austenitic wear-resistant steel according to any one of claims 1-8 in the manufacture of key wear-prone parts of coal mine scraper conveyors, bulldozers, excavators, mixers or loaders.

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