Preparation method of rare earth microalloyed high manganese steel wear-resistant part

Abstract

The invention discloses a preparation method of a rare earth microalloyed high manganese steel wear-resistant part, and belongs to the technical field of wear-resistant materials. The preparation method of the rare earth microalloyed high manganese steel wear-resistant part comprises the following steps that C, Mn, Si, Cr, Mo, Y-based heavy rare earth alloy, silicon-aluminum-barium-calcium alloy and Fe are weighed according to the mass percent, and after electric arc furnace smelting and silicon-aluminum-barium-calcium alloy deoxidation pretreatment, secondary rare earth feeding and alloying are adopted, feeding the residual alloy wires into the pouring cup during pouring; and the molten steel is cast after standing, and a casting blank is subjected to water toughening treatment. Through two-stage rare earth feeding, rare earth burning loss is reduced, a uniform strengthening phase is formed, precise process parameters are matched, the problem of obdurability imbalance of traditional high manganese steel is solved, the hardness, impact toughness and wear resistance of a wear-resistant part are improved, the wear-resistant part is suitable for mine crusher hammerheads and excavator bucket teeth, the service life is prolonged, the process is controllable, and the wear-resistant part is suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of wear-resistant materials, and particularly relates to a preparation method of a rare earth micro-alloyed high manganese steel wear-resistant part. BACKGROUND

[0002] In the core industrial fields such as mining, metallurgical smelting and building infrastructure, the key wear-resistant parts of crushing and excavating equipment are important components to ensure the continuous operation of production. These parts are in extreme working conditions of high impact and strong wear for a long time, and need to resist repeated impact, extrusion and abrasive cutting of materials. The wear resistance and structural stability of these parts directly determine the operation efficiency, maintenance frequency and comprehensive production cost of the equipment. With the upgrading of modern industry to large-scale and high-efficiency, the performance short board of traditional wear-resistant materials is increasingly prominent with the increase of material handling capacity and material hardness, which has become a core bottleneck restricting the release of industry capacity and cost control.

[0003] The mainstream wear-resistant material currently applied in the industry is mainly traditional high manganese steel, which depends on the single-phase austenite structure formed after water toughening treatment to achieve surface hardness improvement through work hardening under extremely high impact stress, and has been widely used in medium and high impact wear scenarios. However, the performance defects of traditional high manganese steel have failed to meet the current industrial needs: first, the work hardening threshold is high, and under medium impact or low stress wear conditions, the surface hardness can only be maintained at 200-300 HB, the wear rate is extremely fast, and frequent replacement is required, which not only increases the cost of spare parts procurement, but also causes 2-4 hours of daily downtime, resulting in an annual loss of capacity of thousands of tons; second, the austenite matrix has low strength and is prone to plastic deformation under long-term impact, such as the problem of reduced bite force of excavator teeth due to deformation, which can cause incomplete material crushing and increase the load of subsequent screening processes, forming a production chain reaction.

[0004] To improve the performance of high manganese steel, the industry has tried to optimize its structure through alloying modification, and common solutions include adding Cr and Mo to improve the matrix strength, or introducing V and Ti to form carbide strengthening phase. However, such solutions have inherent limitations: a single alloying element cannot balance the relationship between hardness and toughness, the addition of Cr can promote the precipitation of M7C3 carbide to increase hardness, but the carbide tends to aggregate at the grain boundaries, resulting in a 40%-60% decrease in material toughness and easy brittle fracture under impact load; if the particle size of V and Ti carbide is not properly controlled, it will become a stress concentration source and accelerate crack initiation. In addition, in the traditional alloying process, the alloying elements are not uniformly dissolved and the composition is severely segregated, resulting in a performance fluctuation of more than 20% in the same batch of parts, which cannot meet the stability requirements of industrial production.

[0005] At the manufacturing process level, traditional high-manganese steel production also has many shortcomings. The smelting stage often uses industrial frequency induction furnaces with crude temperature control, easily leading to insufficient dissolution of key elements such as Mn and C, resulting in localized component segregation. The deoxidation process mainly uses Si-Mn composite deoxidation, which has low deoxidation efficiency, resulting in residual oxygen content in the molten steel >50ppm. This easily generates brittle inclusions such as FeO and SiO2. These inclusions, after enriching at grain boundaries, significantly reduce grain boundary bonding strength and become the main pathway for crack propagation. In the water toughening process, if the heating rate is too fast or the cooling rate is insufficient, carbides may not completely dissolve into austenite or may precipitate secondary, destroying the single-phase structure and directly weakening the material's work hardening ability.

[0006] In existing technologies, research on the application of rare earth elements in high-manganese steel is limited and the designs are often crude. Rare earth elements are frequently directly incorporated into rare earth alloy blocks. Due to their high chemical reactivity and low melting point, rare earth elements experience a burn-off rate of 40%-60% in molten steel at high temperatures. This not only fails to refine grains and purify grain boundaries but may also degrade material properties due to rare earth oxide inclusions. Furthermore, the lack of synergistic design between rare earth elements and other elements and process parameters makes it difficult to achieve targeted control of microstructure and properties through microalloying. Summary of the Invention

[0007] To address the aforementioned shortcomings, this invention provides a method for preparing rare-earth microalloyed high-manganese steel wear-resistant parts. By combining rare-earth microalloying with precise processing, the method solves the problems of imbalance between strength and toughness, rapid wear, and short lifespan of traditional high-manganese steel wear-resistant parts.

[0008] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0009] A method for preparing rare-earth microalloyed high-manganese steel wear-resistant parts includes the following steps:

[0010] (1) Weigh the raw materials by mass percentage: C 0.9-1.5%, Mn 11-14%, Si 0.3-0.8%, Cr 0.5-3.0%, Mo 0.2-1.0%, P≤0.05%, S≤0.05%, Y-based heavy rare earth alloy 0.02-0.07%, silicon-aluminum-barium-calcium alloy 0.1-0.3%, with the balance being Fe;

[0011] (2) Raw material smelting: The C, Mn, Si, P, S and Fe weighed in step (1) are put into an electric arc furnace and smelted at 1520-1580℃ until completely melted to obtain molten steel;

[0012] (3) Deoxidation pretreatment: Add the silicon-aluminum-barium-calcium alloy weighed in step (1) to the molten steel in step (2), and stir at a stirring rate of 300-400 r / min for 15-25 minutes to carry out deoxidation pretreatment.

[0013] (4) Rare earth feeding and alloying: The molten steel is treated by a two-stage rare earth feeding and alloying method;

[0014] First treatment: After the temperature of the deoxidation pretreatment of the molten steel drops to 1480-1520℃, feed alloy wire accounting for 50-70% of the total Y-based heavy rare earth alloy wire into the molten steel at a rate of 0.5-1.2m / min, and at the same time blow nitrogen into the molten steel at a flow rate of 0.8-1.5L / min for 20-35 minutes.

[0015] Second treatment: During the casting process, the remaining alloy, accounting for 30-50% of the total Y-based heavy rare earth alloy wire, is fed into the molten steel at a rate of 0.5-1.2 m / min. The feeding position is in the pouring cup.

[0016] (5) Casting billet: After the first rare earth treatment in step (4), the molten steel is left to stand for 15-20 minutes, and then cast into a precast mold at 1420-1460℃ for the second rare earth treatment. The billet is then cooled to room temperature.

[0017] (6) Water toughening treatment and finished product preparation: The billet is placed in a heat treatment furnace and heated to 1050-1100℃ at a heating rate of 8-12℃ / min. It is then kept at the temperature for 3-4 hours to perform water toughening treatment until room temperature, thus obtaining rare earth microalloyed high manganese steel wear-resistant parts.

[0018] Preferably, the raw materials in step (1) also include 0.03-0.08 parts of Nb, which is added in the form of Nb-Fe master alloy.

[0019] Preferably, in step (1), the Y-based heavy rare earth alloy is composed of Y and La in a mass ratio of (6-8):(2-4).

[0020] Preferably, in step (2) during the smelting process, a bottom-blown nitrogen stirring method is used.

[0021] Preferably, in step (3), the mass percentage of each element in the silicon-aluminum-barium-calcium alloy is: Si 41-44%, Al 12.1-16%, Ba 22.6-24%, Ca 14.5-17%, with the remainder being impurities. Among the impurity elements, S≤0.05%, P≤0.05%, Fe≤2.0%, Mn≤0.5%, Cu≤0.1%, Ni≤0.1%, and Cr≤0.1%.

[0022] Preferably, the preparation process of Y-based heavy rare earth alloy wire in step (4) includes: taking the Y-based heavy rare earth alloy weighed in step (1), crushing and vacuum drying, and cold isostatically pressing the dried particles under a pressure of 200-300MPa to form a billet; placing the billet in a vacuum sintering furnace and heating it to 800-900℃ for 1.5-2 hours.

[0023] Preferably, after the billet is sintered, it is drawn in multiple passes using a cemented carbide mold. The diameter of the mold hole in each pass is reduced by 0.5-1mm compared to the previous pass. After every 3-5 passes of drawing, intermediate annealing is carried out under vacuum.

[0024] Preferably, the wire is finally formed by a die with a diameter of 1-3 mm and cut into Y-based heavy rare earth alloy wire.

[0025] Preferably, during the second wire feeding in step (4), the casting speed is controlled at 0.3-0.5 m / s, and the wire feeding rate matches the casting speed.

[0026] Preferably, the rare earth microalloyed high manganese steel wear-resistant part is a mining crusher hammer or an excavator bucket tooth.

[0027] Compared with the prior art, the present invention has the following advantages and technical effects:

[0028] I. Breaking through the limitations of traditional alloying, constructing a multi-faceted synergistic strengthening system

[0029] This invention innovatively introduces a composite microalloying mechanism of chromium, molybdenum, and Y-based heavy rare earth alloys, breaking through the limitations of traditional high-manganese steel's single austenite solid solution strengthening. Chromium improves austenite stability and promotes the formation of a dense oxide film on the surface, while molybdenum refines grains and enhances grain boundary bonding. The synergistic effect of these two elements with manganese significantly improves the matrix's resistance to plastic deformation. Y-based heavy rare earth alloys, as surface-active elements, not only purify grain boundaries but also form dispersed rare earth nitride strengthening phases with nitrogen. Through the dual effects of pinning dislocations and hindering crack propagation, they achieve a synergistic improvement in strength and toughness. This system effectively solves the technical contradiction of a sharp drop in toughness with increased hardness in traditional high-manganese steel, enabling the material to possess both excellent wear resistance and impact resistance.

[0030] II. Innovative secondary rare earth feeding process significantly improves rare earth utilization efficiency.

[0031] To address the problems of high burn-off rate and uneven distribution in traditional rare earth addition methods, this invention designs a two-stage rare earth feeding process involving in-furnace pretreatment and instantaneous feeding into the pouring cup: the first feeding, through precise temperature control and nitrogen protection, ensures that 50-70% of the rare earth alloy wire is fully dissolved and evenly distributed in the molten steel, forming a matrix strengthening effect; the second feeding is completed in the pouring cup during the casting process, utilizing the shearing action of the molten steel flow to rapidly disperse the remaining rare earth, simultaneously participating in heterogeneous nucleation during solidification, refining the as-cast microstructure. This process increases the rare earth utilization rate to over 80%, avoids the local enrichment or burn-off waste caused by traditional blocky addition, and solves the industry problem of unstable rare earth strengthening effect.

[0032] III. Optimize deoxidation and smelting processes to achieve deep purification of molten steel.

[0033] This invention employs a silicon-aluminum-barium-calcium alloy for composite deoxidation. Through the synergistic effect of multiple elements: silicon and aluminum preferentially combine with oxygen to form low-melting-point oxides, while barium and calcium promote the flotation of non-metallic inclusions through desulfurization and adsorption. Combined with a stirring rate of 300-400 r / min, the inclusion content in the molten steel can be reduced to below 0.005%. Simultaneously, a precise melting temperature of 1520-1580℃ and bottom-blown nitrogen stirring ensure complete dissolution of elements such as carbon and manganese while avoiding element loss and oxidation of the molten steel due to high temperatures. This process effectively removes brittle inclusions commonly found in traditional high-manganese steel, eliminates crack initiation sites, and significantly improves the material's impact toughness and fatigue life.

[0034] IV. Precisely adjust water toughening parameters to optimize austenitic structure stability

[0035] This invention achieves directional control and performance optimization of austenitic structure by precisely locking the parameters of the entire water toughening process: a steady heating rate of 8-12℃ / min avoids thermal stress cracking caused by excessive temperature difference between the inside and outside of the billet, while allowing sufficient time for carbides to gradually dissolve into austenite; the synergistic effect of a holding range of 1050-1100℃ and a holding time of 3-4 hours ensures that all kinds of carbides in the billet are completely dissolved in the austenitic matrix, eliminating the problem of carbide residue caused by insufficient holding in traditional processes.

[0036] Compared to the defects such as carbide segregation and coarse grains often found in traditional water-toughening treatments, the austenitic microstructure obtained by this process exhibits uniform and refined characteristics, with a consistent matrix composition and no localized carbon-depleted or carbide-aggregated areas. This superior microstructure allows the material to absorb energy more fully through plastic deformation under impact loads, effectively avoiding brittle fracture caused by stress concentration. It fundamentally solves the technical bottleneck of accurately balancing strength and toughness after traditional water-toughening treatment of high-manganese steel, providing a core guarantee for the stable service of wear-resistant parts under high-impact wear conditions.

[0037] V. It has strong process adaptability and industrial application value.

[0038] The raw material system and process parameters of this invention are both within the industrially controllable range. Secondary rare earth feeding can be achieved by modifying existing wire feeders and casting systems, without requiring large-scale equipment upgrades. The resulting wear-resistant parts can withstand impact and wear environments under complex working conditions, significantly extending their service life. Combining technological advancement with economic feasibility, this invention provides a practical solution for the large-scale production of high-end wear-resistant materials.

[0039] The dual technical advantages of secondary rare earth feeding and alloying treatment:

[0040] The first in-furnace treatment can further deoxidize and degas the molten steel, while also achieving full alloying of rare earth elements with the molten steel, ensuring a uniform distribution of the molten steel composition, and laying the foundation for the quality of subsequent billets.

[0041] The second casting process, while continuing to deoxidize, degas, fully alloy, and homogenize the composition, can also perform instantaneous inoculation treatment on the molten steel, effectively increasing the number of nuclei, refining the grain structure, and further improving the hardness, impact toughness, and wear resistance of the final wear-resistant parts. Detailed Implementation

[0042] The present invention will now be described in detail with reference to specific embodiments. These embodiments will help those skilled in the art to further understand the present invention, but do not limit the invention in any way. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention. These all fall within the scope of protection of the present invention.

[0043] In this invention, a method for preparing a rare-earth microalloyed high-manganese steel wear-resistant part includes the following steps:

[0044] (1) Weigh the raw materials by mass percentage: C 0.9-1.5%, Mn 11-14%, Si 0.3-0.8%, Cr 0.5-3.0%, Mo 0.2-1.0%, P≤0.05%, S≤0.05%, Y-based heavy rare earth alloy 0.02-0.07%, silicon-aluminum-barium-calcium alloy 0.1-0.3%, with the balance being Fe;

[0045] (2) Raw material smelting: The C, Mn, Si, P, S and Fe weighed in step (1) are put into an electric arc furnace and smelted at 1520-1580℃ until completely melted to obtain molten steel;

[0046] (3) Deoxidation pretreatment: Add the silicon-aluminum-barium-calcium alloy weighed in step (1) to the molten steel in step (2), and stir at a stirring rate of 300-400 r / min for 15-25 minutes to carry out deoxidation pretreatment.

[0047] (4) Rare earth feeding and alloying: The molten steel is treated by a two-stage rare earth feeding and alloying method;

[0048] First treatment: After the temperature of the deoxidation pretreatment of the molten steel drops to 1480-1520℃, feed alloy wire accounting for 50-70% of the total Y-based heavy rare earth alloy wire into the molten steel at a rate of 0.5-1.2m / min, and at the same time blow nitrogen into the molten steel at a flow rate of 0.8-1.5L / min for 20-35 minutes.

[0049] Second treatment: During the casting process, the remaining alloy, accounting for 30-50% of the total Y-based heavy rare earth alloy wire, is fed into the molten steel at a rate of 0.5-1.2 m / min. The feeding position is in the pouring cup.

[0050] (5) Casting billet: After the first rare earth treatment in step (4), the molten steel is left to stand for 15-20 minutes, and then cast into a precast mold at 1420-1460℃ for the second rare earth treatment. The billet is then cooled to room temperature.

[0051] (6) Water toughening treatment and finished product preparation: The billet is placed in a heat treatment furnace and heated to 1050-1100℃ at a heating rate of 8-12℃ / min. It is then kept at the temperature for 3-4 hours to perform water toughening treatment until room temperature, thus obtaining rare earth microalloyed high manganese steel wear-resistant parts.

[0052] The mechanisms of action of each preparation step are as follows:

[0053] In the raw material system, carbon and manganese form the core austenitic matrix. 0.9-1.5% carbon provides a stable carbon content for the austenitic matrix, while 11-14% manganese expands the austenitic region through solid solution strengthening. Together, they ensure the matrix possesses excellent plastic deformation capabilities. Chromium and molybdenum form a composite strengthening effect: chromium enhances oxidation resistance by increasing the matrix electrode potential and promotes uniform carbide precipitation; molybdenum refines grains and improves the hardenability of steel, delaying carbide aggregation and growth at high temperatures. Together with manganese, they enhance the high-temperature stability of the matrix. Y-based heavy rare earth alloys play multiple roles: Y's strong deoxidizing and desulfurizing capabilities purify grain boundaries, while lanthanum's surface activity inhibits P and S segregation. Optimizing their ratio achieves synergistic effects of grain boundary purification and microalloying. In silicon-aluminum-barium-calcium alloys, silicon and aluminum act as the main deoxidizing elements, generating low-melting-point composite oxides. Barium and calcium reduce the melting point of inclusions and promote flotation through dilution effects. This quaternary synergy achieves deep purification of the molten steel.

[0054] The synergistic mechanism of the process steps is reflected in: the precise matching of element dissolution characteristics within the 1520-1580℃ melting temperature range ensures complete solid solution of alloying elements such as chromium and molybdenum while avoiding excessive burning of manganese. A deoxidation stirring rate of 300-400 r / min creates a dynamic balance of convection and flotation, ensuring thorough separation of deoxidation products without secondary oxidation. The secondary rare earth feeding process is innovative: the first feeding utilizes high temperature to promote uniform diffusion of rare earths, combined with 0.8-1.5 L / min nitrogen to form a dispersed rare earth nitride strengthening phase; the second feeding utilizes the flow of molten steel to achieve instantaneous mixing, and the matching of the 0.3-0.5 m / s casting speed with the wire feeding rate ensures uniform distribution of rare earths at the solidification front, inhibiting columnar crystal growth.

[0055] Optimization of water-cooling process parameters plays a crucial role: a heating rate of 8-12℃ / min prevents premature carbide precipitation, and holding at 1050-1100℃ ensures complete dissolution of carbides into austenite; combined with rapid water cooling, this achieves stabilization of the supersaturated solid solution. The preparation process of Y-based heavy rare earth alloy wire ensures the uniformity of alloy wire composition and the compactness of its structure, providing a guarantee for precise feeding.

[0056] The combined effect of the aforementioned raw material synergy and process optimization breaks through the bottleneck of the traditional imbalance between strength and toughness in high manganese steel. Through multiple mechanisms such as solid solution strengthening, second phase strengthening, and grain boundary purification, the comprehensive performance of wear-resistant parts is significantly improved.

[0057] To make the present invention more fully disclosed, more specific embodiments are described below.

[0058] I. Implementation Examples

[0059] Example 1

[0060] A method for preparing rare-earth microalloyed high-manganese steel wear-resistant parts includes the following steps:

[0061] (1) Raw material preparation: Weigh out the following by mass percentage: C 1.2%, Mn 12.5%, Si 0.5%, Cr 1.8%, Mo 0.6%, P 0.03%, S 0.03%, Y-based heavy rare earth alloy (Y and La in a mass ratio of 7:3 composite) 0.04%, silicon-aluminum-barium-calcium alloy (Si 42.9%, Al 15.1%, Ba 24%, Ca 16.5%, with the balance being impurities, of which S 0.03%, P 0.03%, Fe 1.0%, Mn 0.29%, Cu 0.05%, Ni 0.05%, Cr 0.05%) 0.2%, with the balance being Fe. The preparation of Y-based heavy rare earth alloy wire requires taking the above-mentioned Y-based heavy rare earth alloy, crushing it, and then vacuum drying it at 90°C for 2.5 hours. The dried particles are then cold isostatically pressed into billets under a pressure of 250MPa. The billets are placed in a vacuum sintering furnace and heated to 850°C for 1.8 hours. Subsequently, multiple wire drawing is performed using a cemented carbide die, with the die aperture of each pass being 0.8mm smaller than the previous pass. After every 4 passes of wire drawing, intermediate annealing is performed at 650°C for 1.2 hours in a vacuum environment. Finally, the wire is drawn and shaped using a die with a 2mm aperture and cut into 2m long Y-based heavy rare earth alloy wires.

[0062] (2) Raw material smelting: The C, Mn, Si, P, S and Fe weighed in step (1) are put into an electric arc furnace and smelted at 1550℃ until completely melted. During the smelting process, bottom-blown nitrogen is used for stirring to obtain molten steel.

[0063] (3) Deoxidation pretreatment: Add silicon-aluminum-barium-calcium alloy to the molten steel in step (2) and stir at a stirring rate of 350 r / min for 20 minutes to carry out deoxidation pretreatment.

[0064] (4) Rare earth feeding and alloying

[0065] First treatment: After the temperature of the deoxidized steel melt is reduced to 1500℃, Y-based heavy rare earth alloy wire, accounting for 60% of the total alloy wire, is fed in at a rate of 0.8m / min, while nitrogen gas is blown in at a flow rate of 1.2L / min for 28 minutes.

[0066] Second treatment: During the casting process, the casting speed is controlled at 0.4 m / s, and the remaining 40% of Y-based heavy rare earth alloy wire is fed into the pouring cup at a rate of 0.8 m / min along with the molten steel.

[0067] (5) Casting: After the first rare earth treatment in step (4), the molten steel is left to stand for 18 minutes, and then cast into a precast mold at 1440℃ for the second rare earth treatment. The molten steel is then cooled to room temperature to obtain a billet.

[0068] (6) Water toughening treatment and finished product preparation: The billet is placed in a heat treatment furnace and heated to 1080℃ at a heating rate of 10℃ / min. It is then kept at the temperature for 3.5 hours to perform water toughening treatment until room temperature, thus obtaining the hammerhead of the mining crusher.

[0069] Single-factor experimental design and results of key process parameters

[0070] (I) Experimental Design Principles

[0071] Using Example 1 as the baseline, each key process parameter was set to five levels: "below the lower limit, near the lower limit, optimal value, near the upper limit, and above the upper limit," while keeping other parameters constant. The testing indicators were hardness (HRC) and impact toughness (J / cm²). 2 Wear loss (mg) was measured, and the average value was taken for each group after 3 tests to verify the influence of parameters on performance.

[0072] (II) Summary of Single-Factor Experiment Results

[0073] The results of the single-factor experiments are shown in Table 1-5.

[0074]

[0075] (III) Analysis of Single-Factor Experiment Results

[0076] 1. Melting temperature

[0077] (1) Below 1520℃: Elements such as C and Mn are not completely dissolved, resulting in uneven composition of the molten steel and the formation of local carbon / manganese-depleted regions. The carbon-depleted regions cannot form stable austenite, causing the hardness to drop to 55.7 HRC. Compositional segregation also causes grain boundary stress concentration, reducing the impact toughness to 14.2 J / cm. 2 The wear loss increased to 18.5 mg.

[0078] (2) Above 1580℃: High temperature causes Mn to volatilize and burn off, austenite stability decreases, and steel oxidation intensifies, forming brittle FeO inclusions, hardness drops to 60.2HRC, and impact toughness drops to 16.3J / cm. 2 .

[0079] (3) Conclusion: 1520-1580℃ is the equilibrium range between complete dissolution of elements and low burn-off, and 1550℃ is the optimal value.

[0080] 2. Deoxidation stirring rate

[0081] (1) Below 300 r / min: Insufficient stirring intensity prevents the deoxidation products such as Al2O3 and BaSiO3 generated by the silicon-aluminum-barium-calcium alloy from fully floating to the surface, leaving them in the molten steel to form inclusions. These inclusions act as crack initiation sites, causing the impact toughness to drop to 13.8 J / cm. 2 Meanwhile, inclusions weaken the continuity of the matrix, reducing the hardness to 56.3 HRC and increasing wear weight loss to 19.2 mg.

[0082] (2) Above 400 r / min: The molten steel churns violently, destroying the inert protective atmosphere formed by bottom-blown nitrogen. Air entrainment leads to secondary oxidation, and high-speed stirring easily causes the temperature of the molten steel to drop sharply, affecting the subsequent dissolution of rare earth elements. The hardness drops to 58.7 HRC, and the impact toughness drops to 15.6 J / cm. 2 .

[0083] (3) Conclusion: 300-400 r / min is the range in which the product floats sufficiently and there is no secondary oxidation, and 350 r / min is the optimal value.

[0084] 3. First rare earth wire feeding rate

[0085] (1) Below 0.5 m / min: The slow wire feeding leads to the local enrichment of rare earth alloy wire in molten steel, forming brittle rare earth compounds (such as Y2O3), which intensifies grain boundary embrittlement and reduces impact toughness to only 14.9 J / cm². Uneven distribution of rare earth causes the strengthening phase (rare earth nitrides) to be missing locally, reducing hardness to 56.8 HRC and increasing wear weight loss to 17.6 mg.

[0086] (2) Above 1.2 m / min: The wire feeding speed is too fast, resulting in incomplete dissolution of the rare earth alloy wire. The undissolved particles become stress concentration points, and the impact toughness drops to 16.2 J / cm. 2 Rare earth utilization decreased, and hardness dropped to 58.2 HRC.

[0087] (3) Conclusion: 0.5-1.2 m / min is the range of uniform dissolution and high utilization of rare earth, and 0.8 m / min is the optimal value, which can achieve uniform distribution of the strengthening phase.

[0088] 4. Nitrogen flow rate during the second silk feed

[0089] (1) Below 0.5 L / min: Insufficient nitrogen flow rate prevents sufficient reaction with rare earth elements to form rare earth nitrides, weakening the second-phase strengthening effect and resulting in a hardness of only 56.5 HRC; simultaneously, nitrogen cannot cover the surface of the molten steel, leading to a rare earth oxidation burn-off rate >45% and a drop in impact toughness to 14.3 J / cm. 2 .

[0090] (2) Above 1.0 L / min: Excessive nitrogen flow rate leads to excessive bubbles in the molten steel, resulting in porosity defects after casting, weakening the integrity of the matrix, and reducing the impact toughness to 15.7 J / cm. 2 Excess nitrogen also reacts with Fe to form the Fe4N brittle phase, reducing the hardness to 57.8 HRC.

[0091] (3) Conclusion: 0.5-1.0 L / min is the range of sufficient strengthening phase and no bubble defects, and 0.8 L / min is the optimal value, which can balance the strengthening effect and the quality of the billet.

[0092] 5. Water-cooled heating rate

[0093] (1) Below 8℃ / min: The heating is too slow, and the billet stays in the 500-800℃ range for too long. Carbides in the austenite precipitate prematurely and accumulate at the grain boundaries. The carbides embrittle the grain boundaries, and the impact toughness drops to 16.7J / cm. 2 Meanwhile, carbides consume carbon in the matrix, austenite stability decreases, hardness drops to 58.1 HRC, and wear weight loss increases to 15.5 mg.

[0094] (2) Above 12℃ / min: The temperature rises too quickly, and the temperature difference between the inside and outside of the billet reaches 80℃, resulting in uneven microstructure (coarse austenite grains on the surface and undissolved carbides in the core). The coarse grains reduce the matrix strength, and the hardness drops to 59.3HRC. The uneven microstructure causes stress concentration, and the impact toughness drops to 15.8J / cm. 2 .

[0095] (3) Conclusion: 8-12℃ / min is the range for complete dissolution of carbides and uniform tissue structure, and 10℃ / min is the optimal value.

[0096] A method for preparing rare-earth microalloyed high-manganese steel wear-resistant parts includes the following steps:

[0097] (1) Raw material preparation: Weigh out the following by mass percentage: C 1.2%, Mn 12.5%, Si 0.5%, Cr 1.8%, Mo 0.6%, P 0.03%, S 0.03%, Y-based heavy rare earth alloy (Y and La in a mass ratio of 7:3 composite) 0.04%, silicon-aluminum-barium-calcium alloy (Si 42.9%, Al 15.1%, Ba 24%, Ca 16.5%, with the balance being impurities, including S 0.03%, P 0.03%, Fe 1.0%, Mn 0.29%, Cu 0.05%, Ni 0.05%, Cr 0.05%) 0.2%, Nb 0.05% (added as an Nb-Fe master alloy with Nb accounting for 62% of the mass), with the balance being Fe. The preparation process of the Y-based heavy rare earth alloy wire is the same as in Example 1.

[0098] (2) Raw material smelting: The C, Mn, Si, P, S, Fe, and Nb-Fe master alloy weighed in step (1) are put into an electric arc furnace and smelted at 1530°C until completely melted. During the smelting process, bottom-blown nitrogen is used for stirring to obtain molten steel.

[0099] (3) Deoxidation pretreatment: Add silicon-aluminum-barium-calcium alloy to the molten steel in step (2) and stir at a stirring rate of 300 r / min for 25 minutes to carry out deoxidation pretreatment.

[0100] (4) Rare earth feeding and alloying

[0101] First treatment: After the temperature of the deoxidized pretreated steel is reduced to 1490℃, Y-based heavy rare earth alloy wire, accounting for 65% of the total alloy wire, is fed in at a rate of 0.6m / min, while nitrogen gas is blown into the steel at a flow rate of 1.0L / min for 35 minutes.

[0102] Second treatment: During the casting process, the casting speed is controlled at 0.35m / s, and the remaining 35% of Y-based heavy rare earth alloy wire is fed into the pouring cup at a rate of 0.6m / min along with the molten steel.

[0103] (5) Casting: After the first rare earth treatment in step (4), the molten steel is left to stand for 15 minutes, and then cast into a preheated mold at 1430℃ for the second rare earth treatment. The molten steel is then cooled to room temperature to obtain the billet.

[0104] (6) Water toughening treatment and finished product preparation: The billet is placed in a heat treatment furnace and heated to 1060℃ at 9℃ / min. It is then kept at the temperature for 4 hours to perform water toughening treatment until the temperature returns to room temperature, thus obtaining excavator bucket teeth.

[0105] Example 3

[0106] A method for preparing rare-earth microalloyed high-manganese steel wear-resistant parts includes the following steps:

[0107] (1) Raw material preparation: Weigh out the following by mass percentage: C 1.4%, Mn 14%, Si 0.8%, Cr 3.0%, Mo 1.0%, P 0.05%, S 0.05%, Y-based heavy rare earth alloy (Y and La in a mass ratio of 8:4 composite) 0.07%, silicon-aluminum-barium-calcium alloy (Si 43.5%, Al 15.1%, Ba 23%, Ca 16%, with the balance being impurities, of which S 0.05%, P 0.05%, Fe 1.5%, Mn 0.5%, Cu 0.1%, Ni 0.1%, Cr 0.1%) 0.3%, Nb 0.08% (added as an Nb-Fe master alloy with Nb mass percentage of 65%), with the balance being Fe. The preparation of Y-based heavy rare earth alloy wire requires taking the above-mentioned Y-based heavy rare earth alloy, crushing it, and then vacuum drying it at 100°C for 2 hours; the dried particles are then cold isostatically pressed into billets under a pressure of 300MPa; the billets are placed in a vacuum sintering furnace and heated to 900°C for 2 hours; then, multiple wire drawing is performed using a cemented carbide die, with the die aperture of each pass being 1mm smaller than the previous pass; after every 3 passes of wire drawing, intermediate annealing is performed at 700°C for 1.5 hours in a vacuum environment; finally, the wire is drawn and shaped using a die with a 3mm aperture and cut into 3m long Y-based heavy rare earth alloy wires.

[0108] (2) Raw material smelting: The C, Mn, Si, P, S, Fe, and Nb-Fe master alloy weighed in step (1) are put into an electric arc furnace and smelted at 1580°C until completely melted. During the smelting process, bottom-blown nitrogen is used for stirring to obtain molten steel.

[0109] (3) Deoxidation pretreatment: Add silicon-aluminum-barium-calcium alloy to the molten steel in step (2) and stir at a stirring rate of 400 r / min for 15 minutes to carry out deoxidation pretreatment.

[0110] (4) Rare earth feeding and alloying

[0111] First treatment: After the temperature of the deoxidized pretreated steel is reduced to 1520℃, Y-based heavy rare earth alloy wire, accounting for 70% of the total alloy wire, is fed in at a rate of 1.2m / min, while nitrogen gas is blown into the steel at a flow rate of 1.5L / min for 20 minutes.

[0112] Second treatment: During the casting process, the casting speed is controlled at 0.5 m / s, and the remaining 30% of Y-based heavy rare earth alloy wire is fed into the pouring cup at a rate of 1.2 m / min along with the molten steel.

[0113] (5) Casting: After the first rare earth treatment in step (4), the molten steel is left to stand for 20 minutes, and then cast into a precast mold at 1460℃ for the second rare earth treatment. The molten steel is then cooled to room temperature to obtain a billet.

[0114] (6) Water toughening treatment and finished product preparation: The billet is placed in a heat treatment furnace and heated to 1100℃ at 12℃ / min. It is kept at the temperature for 3 hours for water toughening treatment until room temperature, and the hammer of the mining crusher is obtained.

[0115] Example 4

[0116] A method for preparing rare-earth microalloyed high-manganese steel wear-resistant parts includes the following steps:

[0117] (1) Raw material preparation: Weigh out the following by mass percentage: C 1.1%, Mn 12%, Si 0.4%, Cr 0.6%, Mo 0.2%, P 0.04%, S 0.04%, Y-based heavy rare earth alloy (Y and La in a mass ratio of 6.8:3.2 composite) 0.03%, silicon-aluminum-barium-calcium alloy (Si 43%, Al 14.6%, Ba 23.5%, Ca 17%, with the balance being impurities, of which S 0.02%, P 0.01%, Fe 1.61%, Mn 0.2%, Cu 0.03%, Ni 0.01%, Cr 0.02%) 0.15%, Nb 0.05% (added as an Nb-Fe master alloy with Nb mass percentage of 62%), with the balance being Fe. The preparation of Y-based heavy rare earth alloy wire requires the above-mentioned Y-based heavy rare earth alloy to be crushed and then vacuum dried at 80°C for 3 hours; the dried particles are then cold isostatically pressed into billets under a pressure of 220MPa; the billets are placed in a vacuum sintering furnace and heated to 820°C for 1.6 hours; then, multiple wire drawing is performed using a cemented carbide die, with the die aperture of each pass being 0.6mm smaller than the previous pass; after every 5 passes of wire drawing, intermediate annealing is performed at 600°C for 1 hour in a vacuum environment; finally, the wire is drawn and shaped using a die with an aperture of 1.5mm and cut into 1.5m long Y-based heavy rare earth alloy wires.

[0118] (2) Raw material smelting: The C, Mn, Si, P, S, Fe, and Nb-Fe master alloy weighed in step (1) are put into an electric arc furnace and smelted at 1530°C until completely melted. During the smelting process, bottom-blown nitrogen is used for stirring to obtain molten steel.

[0119] (3) Deoxidation pretreatment: Add silicon-aluminum-barium-calcium alloy to the molten steel in step (2) and stir at a stirring rate of 320 r / min for 22 minutes to carry out deoxidation pretreatment.

[0120] (4) Rare earth feeding and alloying

[0121] First treatment: After the temperature of the deoxidized pretreated steel is reduced to 1490℃, Y-based heavy rare earth alloy wire, accounting for 50% of the total alloy wire, is fed in at a rate of 0.6m / min, while nitrogen gas is blown into the steel at a flow rate of 0.8L / min for 32 minutes.

[0122] Second treatment: During the casting process, the casting speed is controlled at 0.3 m / s, and the remaining 50% of Y-based heavy rare earth alloy wire is fed into the pouring cup at a rate of 0.5 m / min along with the molten steel.

[0123] (5) Casting: After the first rare earth treatment in step (4), the molten steel is left to stand for 16 minutes, and then cast into a precast mold at 1430℃ for the second rare earth treatment. The molten steel is then cooled to room temperature to obtain a billet.

[0124] (6) Water toughening treatment and finished product preparation: The billet is placed in a heat treatment furnace and heated to 1060℃ at 9℃ / min. It is then kept at the temperature for 3.2 hours to undergo water toughening treatment until room temperature, thus obtaining excavator bucket teeth.

[0125] Example 5

[0126] A method for preparing rare-earth microalloyed high-manganese steel wear-resistant parts includes the following steps:

[0127] (1) Raw material preparation: Weigh out the following by mass percentage: C 1.3%, Mn 13%, Si 0.7%, Cr 2.8%, Mo 0.7%, P 0.03%, S 0.03%, Y-based heavy rare earth alloy (Y and La in a mass ratio of 7.2:2.8 composite) 0.06%, silicon-aluminum-barium-calcium alloy (Si 41.9%, Al 16%, Ba 23.4%, Ca 17%, with the balance being impurities, of which S 0.05%, P 0.04%, Fe 1.45%, Mn 0.1%, Cu 0.03%, Ni 0.01%, Cr 0.02%) 0.25%, Nb 0.07% (added as an Nb-Fe master alloy with Nb mass percentage of 64%), with the balance being Fe. The preparation of Y-based heavy rare earth alloy wire requires taking the aforementioned Y-based heavy rare earth alloy, crushing it, and then vacuum drying it at 95°C for 2.2 hours. The dried particles are then cold isostatically pressed into a billet under a pressure of 280MPa. The billet is placed in a vacuum sintering furnace and heated to 880°C for 1.9 hours. Subsequently, multiple wire drawing is performed using a cemented carbide die, with the die aperture decreasing by 0.9mm in each pass. After every 4 passes of wire drawing, intermediate annealing is performed at 680°C for 1.3 hours under vacuum. Finally, the wire is drawn and shaped using a die with a 2.5mm aperture and cut into 2.5m long Y-based heavy rare earth alloy wires.

[0128] (2) Raw material smelting: The C, Mn, Si, P, S, Fe, and Nb-Fe master alloy weighed in step (1) are put into an electric arc furnace and smelted at 1560°C until completely melted. During the smelting process, bottom-blown nitrogen is used for stirring to obtain molten steel.

[0129] (3) Deoxidation pretreatment: Add silicon-aluminum-barium-calcium alloy to the molten steel in step (2) and stir at a stirring rate of 380 r / min for 18 minutes to carry out deoxidation pretreatment.

[0130] (4) Rare earth feeding and alloying

[0131] First treatment: After the temperature of the deoxidized pretreated steel is reduced to 1510℃, Y-based heavy rare earth alloy wire, accounting for 55% of the total alloy wire, is fed in at a rate of 1.0m / min, while nitrogen gas is blown into the steel at a flow rate of 1.3L / min for 25 minutes.

[0132] Second treatment: During the casting process, the casting speed is controlled at 0.45 m / s, and the remaining 45% of Y-based heavy rare earth alloy wire is fed into the pouring cup at a rate of 1.0 m / min.

[0133] (5) Casting: After the first rare earth treatment in step (4), the molten steel was left to stand for 19 minutes, and then cast into a precast mold at 1450℃ for the second rare earth treatment. The molten steel was then cooled to room temperature to obtain a billet.

[0134] (6) Water toughening treatment and finished product preparation: The billet is placed in a heat treatment furnace and heated to 1090℃ at 11℃ / min. It is then kept at the temperature for 3.8 hours to undergo water toughening treatment until room temperature, thus obtaining the hammerhead of the mining crusher.

[0135] II. Comparative Example

[0136] Comparative Example 1 (no secondary rare earth feeding, only single wire feeding)

[0137] Except for the rare earth feeding and alloying steps, the rest of the process is the same as in Example 1.

[0138] Rare earth feeding: After the temperature of the molten steel drops to 1500℃, 100% Y-based heavy rare earth alloy wire is fed in at a rate of 0.8m / min in one go, while nitrogen is blown at 1.2L / min for 28 minutes simultaneously. There is no second casting and wire feeding.

[0139] Comparative Example 2 (Silicon-free aluminum-barium-calcium alloy)

[0140] The deoxidation pretreatment step of adding silicon-aluminum-barium-calcium alloy is omitted, and the remaining steps are the same as in Example 1.

[0141] Comparative Example 3 (Traditional Rare Earth Addition Method)

[0142] Once the temperature of the molten steel drops to 1500℃, Y-based heavy rare earth alloy blocks are directly poured in without nitrogen blowing in for 28 minutes. The remaining steps are the same as in Example 1.

[0143] Except for rare earth feeding, alloying, and alloy wire preparation, the rest of the process is the same as in Example 1.

[0144] Rare earth addition: After the temperature of the molten steel drops to 1500℃, Y-based heavy rare earth alloy blocks are directly added in two batches (60% in the furnace and 40% during casting). The nitrogen blowing parameters are the same as in Example 1.

[0145] III. Summary of Experimental Results:

[0146] The testing items and standards of this invention are shown in Table 6.

[0147]

[0148] (II) Test Results

[0149] The performance of the mining crusher hammers / excavator bucket teeth prepared in Examples 1-5 and Comparative Examples 1-3 was tested, and the results are shown in Table 7.

[0150]

[0151] (III) Data Comparison and Analysis

[0152] 1. Hardness Performance Analysis

[0153] The hardness range of Examples 1-5 was 59.1-65.8 HRC, with Example 1 reaching 65.8 HRC and Example 5 reaching 64.2 HRC, close to the optimal value, due to the increased Y-based heavy rare earth alloy content to 0.06%. In contrast, the highest hardness of Comparative Examples 1-3 was only 56.8 HRC, with Comparative Example 1 even as low as 52.6 HRC. The hardness of Example 1 was significantly improved compared to Comparative Example 1 (25.1%), Comparative Example 2 (21.2%), and Comparative Example 3 (15.8%).

[0154] From a theoretical perspective, the hardness advantage of this invention stems from a multi-component synergistic strengthening mechanism: carbon and manganese form a stable austenitic solid solution, which lays the foundation for matrix strength through lattice distortion. The precise matching of 1.2% carbon and 12.5% ​​manganese maximizes the stability of austenite. The Y-based heavy rare earth alloy reacts with nitrogen to generate dispersed rare earth nitrides. These hard particles can effectively pin dislocation movement and hinder plastic deformation. Furthermore, the 7:3 composite of Y and La can optimize the size of the strengthening phase and avoid stress concentration caused by coarse particles. Optional Nb is added to the molten steel in the form of an Nb-Fe master alloy to form nanoscale NbC particles, further refining the grains and providing additional hard particle support. The deep deoxidation effect of the silicon-aluminum-barium-calcium alloy removes brittle inclusions such as FeO and SiO2 from the molten steel, preventing these inclusions from weakening the matrix strength. In Comparative Example 2, which lacks this component, there are more residual inclusions in the molten steel, resulting in insufficient grain boundary strength and limited hardness improvement. In Comparative Example 1, due to the lack of secondary rare earth feeding, the rare earth distribution is uneven, and the strengthening phase is locally missing, resulting in significantly lower hardness. Comparative Example 3 uses traditional bulk rare earth addition, but the rare earth is easily oxidized and burned off at high temperatures, and there is no nitrogen gas to synergistically form a strengthening phase. Only a small amount of rare earth plays a role, and the hardness improvement is far less than that of the examples.

[0155] 2. Impact toughness analysis

[0156] The impact toughness range of Examples 1-5 is 17.2-21.3 J / cm. 2 Example 1 uses 21.3 J / cm 2 For optimal results, Example 3, with its increased Mn content of 14%, achieved an impact toughness of 19.5 J / cm². 2 The impact toughness remains at a high level; while the highest impact toughness of ratios 1-3 is only 13.6 J / cm. 2 The comparative example is even as low as 10.5 J / cm². 2 Example 1 shows a significant improvement in impact toughness compared to Comparative Example 1 (66.4%), Comparative Example 2 (102.9%), and Comparative Example 3 (56.6%).

[0157] This performance advantage stems from the precise control of material microstructure and grain boundary state: In silicon-aluminum-barium-calcium alloys, Si, Al, Ba, and Ca work synergistically to preferentially combine with oxygen and sulfur in molten steel to form low-melting-point composite oxides and sulfides. These products float to the surface of molten steel with a stirring rate of 300-400 r / min, significantly reducing the content of grain boundary inclusions and reducing crack initiation sources; rare earth elements such as Y and La have strong surface activity and can be adsorbed at grain boundaries, inhibiting the segregation of harmful elements such as P and S at grain boundaries and avoiding grain boundary embrittlement. At the same time, rare earth elements act as heterogeneous nucleation cores, refining austenite grains and shortening crack propagation paths; precise water toughening process ensures that carbides are completely dissolved into austenite, avoiding secondary precipitation of carbides during cooling that would damage the single-phase austenite structure, giving the material excellent plastic deformation capacity to absorb impact energy. Comparative Example 1, lacking secondary rare earth feeding, had coarse grains and uneven rare earth distribution, resulting in insufficient impact toughness. Comparative Example 2, lacking silicon-aluminum-barium-calcium alloy deoxidation, had high inclusion content in the molten steel, which easily triggered crack propagation and significantly reduced toughness. Comparative Example 3, with traditional block-type rare earth addition, resulted in local enrichment of rare earth, forming a brittle phase. At the same time, the lack of nitrogen protection exacerbated rare earth burn-off, failing to fully utilize grain boundary purification and grain refinement effects, thus limiting the improvement in toughness.

[0158] 3. Wear resistance analysis

[0159] The wear loss range of Examples 1-5 was 6.7-10.5 mg, with Example 1 showing the optimal value of 6.7 mg. Example 5, due to the increased rare earth content to 0.06%, had a wear loss of only 7.5 mg, approaching optimal wear resistance. In contrast, Comparative Examples 1-3 showed the lowest wear loss at 19.8 mg, with Comparative Example 1 reaching as high as 25.4 mg. The wear loss of Example 1 was reduced by 73.6% compared to Comparative Example 1, 69.7% compared to Comparative Example 2, and 66.2% compared to Comparative Example 3, demonstrating a significant improvement in wear resistance.

[0160] This significant difference is attributed to the wear-resistant system constructed in this invention, which features high hardness, resistance to cutting, high toughness, resistance to spalling, and surface protection: the rare earth nitrides, NbC, and other reinforcing phases have extremely high hardness and are uniformly distributed in the matrix, directly resisting the cutting and grooving action of abrasive particles and reducing surface material loss; the material's excellent impact toughness prevents hard particles from falling off under impact loads, preventing the formation of new wear areas due to hard particle detachment and maintaining the integrity of the wear-resistant surface; rare earth elements can also promote the formation of a dense oxide protective film on the surface during friction, which can reduce the coefficient of friction and further reduce the damage of abrasive particles to the material surface. Comparative Example 1 lacked secondary rare earth feeding, resulting in uneven distribution and insufficient quantity of the reinforcing phase. It relied solely on the hardness of the matrix itself to resist wear, making it prone to abrasive cutting of surface materials and leading to significant wear-related weight loss. Comparative Example 2 suffered from poor material toughness due to numerous inclusions, causing hard particles to easily detach and increasing surface defects during wear, resulting in increased wear-related weight loss. Comparative Example 3, using traditional rare earth addition methods, resulted in low rare earth utilization, insufficient quantity and uneven distribution of the reinforcing phase, and the absence of nitrogen to form a protective oxide film and rare earth nitrides. Its wear resistance was far inferior to that of the examples, fully demonstrating that the technology of this invention has made significant progress in improving the wear resistance of wear-resistant parts.

[0161] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A method for producing a rare earth microalloyed high manganese steel wear part, characterized in that, The method comprises the following steps: (1) taking raw materials according to mass percentage: C 0.9-1.5%, Mn 11-14%, Si 0.3-0.8%, Cr 0.5-3.0%, Mo 0.2-1.0%, P≤0.05%, S≤0.05%, Y base weight rare earth alloy 0.02-0.07%, silicon aluminum barium calcium alloy 0.1-0.3%, and the balance being Fe; (2) raw material smelting: the C, Mn, Si, P, S and Fe taken in step (1) are put into an electric arc furnace, and smelting is carried out at 1520-1580 ℃ until complete melting, so that a molten steel is obtained; (3) deoxidation pretreatment: the silicon aluminum barium calcium alloy taken in step (1) is added to the molten steel of step (2), and deoxidation pretreatment is carried out by stirring at a stirring rate of 300-400 r / min for 15-25 minutes; (4) rare earth feeding and alloying: the molten steel is treated by adopting a two-stage rare earth feeding and alloying mode; first treatment: after the deoxidation pretreatment, the temperature of the molten steel is reduced to 1480-1520 ℃, and the alloy wire accounting for 50-70% of the total Y base weight rare earth alloy wire is fed into the molten steel at a rate of 0.5-1.2 m / min, and nitrogen gas is blown into the molten steel at a flow rate of 0.8-1.5 L / min, and the process lasts for 20-35 minutes; second treatment: during the casting process, the remaining alloy wire accounting for 30-50% of the total Y base weight rare earth alloy wire is fed into the molten steel at a rate of 0.5-1.2 m / min, and the feeding position is in the pouring cup; (5) casting blank forming: the molten steel after the first rare earth treatment in step (4) is left to stand for 15-20 minutes, and then cast into a preform mold at 1420-1460 ℃ during the second rare earth treatment, and cooled to room temperature to obtain a casting blank; (6) water toughening treatment and finished product preparation: the casting blank is placed in a heat treatment furnace, heated to 1050-1100 ℃ at a heating rate of 8-12 ℃ / min, and held for 3-4 hours for water toughening treatment to room temperature, to obtain a rare earth micro-alloyed high manganese steel wear-resistant part.

2. The method of claim 1, wherein the rare earth microalloyed high manganese steel wear part is prepared by the steps of: The raw materials in step (1) also include Nb 0.03-0.08 parts, and the Nb is added in the form of Nb-Fe intermediate alloy. ​ 3. The method of claim 1, wherein the rare earth microalloyed high manganese steel wear part is prepared by the steps of: The Y base weight rare earth alloy in step (1) is composed of Y and La at a mass ratio of (6-8):(2-4). ​ 4. The method of claim 1, wherein the rare earth microalloyed high manganese steel wear part is prepared by the steps of: During the smelting process in step (2), a nitrogen gas stirring mode is adopted. ​ 5. The method for preparing rare-earth microalloyed high-manganese steel wear-resistant parts according to claim 1, characterized in that, In step (3), the mass percentage of each element in the silicon aluminum barium calcium alloy is as follows: Si 41-44%, Al 12.1-16%, Ba 22.6-24%, Ca 14.5-17%, and the balance is impurities, and the impurities include S≤0.05%, P≤0.05%, Fe≤2.0%, Mn≤0.5%, Cu≤0.1%, Ni≤0.1%, and Cr≤0.1%.

6. The method of claim 1, wherein the rare earth microalloyed high manganese steel wear part is prepared by the steps of: The preparation process of the Y-based heavy rare earth alloy wire in step (4) comprises the following steps: taking the Y-based heavy rare earth alloy obtained in step (1), crushing and vacuum drying, cold isostatic pressing the dried particles under a pressure of 200-300 MPa to obtain a blank, and placing the blank in a vacuum sintering furnace, heating to 800-900 ℃ and keeping for 1.5-2 hours. ​ 7. The method of manufacturing a rare earth micro-alloyed high manganese steel wear part according to claim 6, characterized in that, After sintering of the blank, a plurality of passes of wire drawing are performed using a hard alloy die, the aperture of the die in each pass is reduced by 0.5-1 mm compared with the aperture in the previous pass, and after 3-5 passes of wire drawing, intermediate annealing is performed under vacuum.

8. The method of manufacturing a rare earth micro-alloyed high manganese steel wear part according to claim 7, characterized in that, The wire drawing is finally performed through a die with an aperture of 1-3 mm, and the Y-based heavy rare earth alloy wire is obtained by cutting.

9. The method of producing a rare earth microalloyed high manganese steel wear part according to claim 1, characterized in that, In the second wire feeding in step (4), the casting speed is controlled to be 0.3-0.5 m / s, and the wire feeding speed is matched with the casting speed.

10. The method of claim 1, wherein the rare earth microalloyed high manganese steel wear part is prepared by the steps of: The rare earth micro-alloyed high manganese steel wear-resistant part is a hammer head of a mine crusher or a bucket tooth of an excavator. ​

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