High-toughness wear-resistant steel ball and preparation method thereof

Abstract

The invention discloses a high-toughness wear-resistant steel ball and a preparation method thereof, and belongs to the technical field of wear-resistant alloy steel. A medium-frequency induction furnace is used for smelting molten steel, and waste steel, a carburant, ferrochrome, ferrosilicon, metal aluminum and nitrided ferromanganese serve as main furnace charges. The method comprises the following steps: after the molten steel is subjected to slagging-off and standing, when the temperature is reduced to 1518-1533 DEG C, pouring the molten steel on a continuous casting machine to form a round steel bar with the diameter phi of 90-100mm, putting the round steel bar into a heating furnace for heating, after the round steel bar is uniformly heated to 1180-1250 DEG C and is subjected to heat preservation for 45-60 minutes, cutting the round steel bar into steel sections, controlling the length of the steel sections to be 180-225mm, then forging the steel sections into steel balls, and carrying out hot rolling on the steel balls to obtain the steel balls. And the steel balls are subjected to quenching and tempering treatment, so that the steel balls with high strength and hardness and good toughness and wear resistance are obtained, and the steel balls are applied to large mills, have good use effects and have good economic and social benefits in popularization and application.

Description

Technical Field

[0001] The invention discloses a wear-resistant steel ball and a preparation method thereof, in particular to a high-strength and toughness wear-resistant steel ball and a preparation method thereof, belonging to the technical field of wear-resistant alloy steel. Background Art

[0002] Wear-resistant steel balls are easily worn parts widely used in industrial production such as metallurgy, mineral processing, building materials, chemicals, and electric power. The annual consumption of steel balls in the world is nearly 10 million tons. The service life of wear-resistant steel balls directly affects the production efficiency of the mill. The requirements for wear-resistant steel balls are that they must have sufficient strength and hardness, as well as good impact toughness. In the prior art, wear-resistant steel balls are mainly divided into three categories: forged steel balls, cast steel balls, and hot-rolled steel balls. Among them, cast steel balls are mainly chromium alloys, such as high-chromium steel balls, medium-chromium steel balls, low-chromium steel balls, and vanadium-titanium-chromium alloy steel balls. During use, there are defects such as low impact toughness and poor wear resistance. With the needs of large-scale production, ball mill models are gradually developing in the direction of large-scale, and higher requirements are also put forward for the impact toughness and wear resistance of steel balls. In order to adapt to this trend, it is necessary to develop a wear-resistant steel ball with stable quality, higher hardness, better toughness, and better wear resistance to reduce steel ball consumption and improve grinding efficiency.

[0003] In order to improve the performance of steel balls, Chinese invention patent CN118291874A discloses a wear-resistant and high-toughness ultra-high chromium steel ball material and its preparation method. The wear-resistant and high-toughness ultra-high chromium steel ball material of the invention includes the following chemical components in mass percentage: C: 2.80% to 3.30%, Si: 0.60% to 0.80%, Mn: 2.00% to 2.50%, W: 0.25% to 0.55%, Mo: 0.25% to 0.45%, Cr: 18.00 to 20.00%, P and S are both less than 0.02%, and the rest are iron and inevitable impurities. The invention further adjusts the element content and processing method in the steel ball material, so that the chromium content in the steel ball material is 18.00% to 20.00%, and at the same time, the steel ball material not only has excellent wear resistance, but also has the characteristics of high toughness, thereby making the ultra-high chromium steel ball material of the invention have a longer service life. Chinese invention patent CN117758135A also discloses a wear-resistant steel ball and its production process. The chemical composition weight percentage of the steel ball is: C3.0-3.2%, Cr 11-26%, Si 0.3-1.2%, Mn 1.2-2.6%, Ni 0-1.5%, P≤0.1%, S≤0.1%, Cu 0-2.0%, and the rest is iron and inevitable impurities. The application adjusts the content of each element in the wear-resistant steel ball raw material and controls the production process to obtain a steel ball with a surface hardness, a steel ball core hardness and an impact toughness of up to 62.7HRC, 60.8HRC and 4.8J / cm 2, and its fatigue life is greater than 18,000 times, with high hardness, impact toughness and fatigue life. Chinese invention patent CN118237584A also discloses a high-performance alloy steel ball and its manufacturing method. The method forms a spherical billet by mixing nano-SiC powder, rare earth element powder and basic steel through high-energy ball milling, and sintering and thermal deformation treatment. Then the internal structure of the steel ball is optimized through normalizing, tempering and quenching treatment. Finally, a nanocrystalline layer is induced on the surface by steel shot impact and high-energy shot peening, and the surface finish is improved by fine grinding and polishing to obtain a high-performance alloy steel ball. This invention not only improves the hardness, wear resistance and impact resistance of the steel ball, but also significantly enhances its corrosion resistance, so that the comprehensive performance of the steel ball is greatly improved, and it is suitable for a variety of harsh working conditions. Chinese invention patent CN118048093A also discloses a wear-resistant hot-rolled steel ball, comprising a hot-rolled steel ball body (1), wherein the hot-rolled steel ball body (1) comprises a wear-resistant coating protective layer (2), a wear-resistant structural cladding (3) and an inner sphere (4), wherein the wear-resistant coating protective layer (2) comprises an epoxy resin coating, a polyurethane coating, a ceramic coating and a metal coating, and the wear-resistant structural cladding (3) comprises a cobalt-based alloy, a nickel-based alloy, a titanium steel alloy and an aluminum alloy structure, and the inner sphere (4) is a 100% carbon steel structure. The wear-resistant hot-rolled steel ball in the invention is heat-treated to have a high hardness, can effectively resist wear and corrosion, and has excellent wear resistance. It is manufactured by hot rolling process, has uniform chemical composition and metallographic structure, has stable performance, has good toughness and plasticity, and can withstand strong impact and deformation. The above-mentioned ultra-high chromium steel ball material contains a large amount of chromium element which is scarce in my country, resulting in a huge waste of resources. In addition, the steel ball is manufactured by powder metallurgy method, which has the disadvantages of high energy consumption and low efficiency. A wear-resistant coating protective layer is added to the surface of the steel ball. The bonding strength between the protective layer and the steel ball body is low, and it is easy to crack and peel off during use, which reduces the wear resistance of the steel ball.

[0004] Chinese invention patent CN117568717A discloses an alloy steel ball for ball mill and its preparation method. The steel ball is made of the following raw materials in mass percentage: C 0.6-1.1%, Si 0.5-1.5%, Mn 1.20-1.50%, Ni 0.05-0.10%, Cr 1.10-1.30%, Nb 0.055-0.065%, P≤0.015%, S≤0.015%, and the rest is Fe; Mn / Si is 1-2.5, Cr / Si is 1-2.5, and Cr / Nb is 18-20. The invention significantly improves the performance of the steel ball by optimizing the composition of the steel ball without changing the existing process. For industrial production, it has low cost, good effect, and is suitable for production application. Chinese invention patent CN117403125A also discloses a short-process preparation method for wear-resistant steel balls with good toughness and hardness containing carbon nanotubes, which belongs to the field of alloy steel manufacturing. The steel ball includes the following raw materials, in mass percentage: C 0.60-0.90%, Si 0.80-1.30%, Mn 0.60-1.00%, Cr 0.60-1.00%, Nb 0.01-0.05%, carbon nanotubes 0.01-0.04%, and the balance is Fe and inevitable impurity elements. The invention adopts an online residual heat quenching heat treatment process to obtain martensite structure and part of bainite in the steel ball, and finally obtains a multiphase structure that is stable at room temperature and contains carbon nanotubes, martensite and bainite. The surface and core hardness can reach more than 60HRC, and the number of 10m ball drop test is more than 5000 times, with a good toughness and hardness ratio. At the same time, the preparation method of the application has a short process, simplifies the production process and shortens the production cycle, saves energy and protects the environment, and reduces costs. However, the density of carbon nanotubes is low, and when a trace amount of carbon nanotubes is added to the wear-resistant steel ball, its uniformity of distribution in the wear-resistant steel ball is poor, and the stability of the performance of the wear-resistant steel ball cannot be ensured.

[0005] Chinese invention patent CN117000924A discloses an online production process for forging steel balls with high hardness and high attack toughness, which relates to the field of steel ball forging production technology. In order to solve the problem that the steel ball forging device in the prior art uses a mold to achieve hot pressing shaping during hot forging operation, due to its circular shape, hot pressing is performed on only one side, which easily leads to uneven and rounded surfaces of other end faces, thus affecting the quality of its molding. The step 1: first prepare the raw materials. The main raw materials of the steel ball are carbon steel, alloy steel, and stainless steel metal materials. The materials are processed to become steel bars that meet the requirements; step 2: the steel bars are cut and cut into small pieces of a certain length. These small pieces are further processed to become steel balls that meet the requirements; step 3: the small pieces after cutting are heat treated, and the heat treatment improves the performance of the steel ball and improves its hardness, strength and toughness. Chinese invention patent CN116875914A also discloses a high-strength and toughness steel ball and a production method thereof. The steel ball contains, by weight percentage, 0.13%-0.15% C, 5.50%-6.70% W, 1.50%-2.50% Mn, 0.25%-0.55% Co, 0.22%-0.45% Mo, and the remainder is Fe and inevitable impurities. A production method for a high-strength and toughness steel ball comprises the following steps: A. smelting iron ore, reducing the ore to molten iron, and desulfurizing; B. introducing high-pressure oxygen into a converter to heat the molten iron, adding lime for dephosphorization, and removing impurities. The present invention performs desulfurization and dephosphorization, thereby improving the toughness of the steel ball. By adding C, W, Mn, Co and Mo into molten iron, C increases the rigidity of the steel ball and has a low content, thereby preventing the steel ball from being too brittle. Mn can increase the strength of the steel, weaken and eliminate the adverse effects of sulfur, and improve the hardenability of the steel. W can increase the red hardness and heat strength of the steel, and improve the wear resistance of the steel. Co further increases the strength of the steel ball. A large amount of expensive tungsten is added to the above steel ball, resulting in a significant increase in the manufacturing cost of the steel ball.

[0006] Chinese invention patent CN116695002A discloses a high-hardness and high-toughness wear-resistant steel ball and its preparation process. The element components and weight ratios of the wear-resistant steel ball are divided into: C: 0.95-1.1%; Si: 0.1-0.4%; Mn: 0.1-0.4%; S: 0.1-0.3%; P: 0.1-0.3%; Cr: 15.0-20.0%; Ni: 1.0-1.5%; Mo: 0.9-1.1%; V: 0.3-0.6%, Nb: 0.2-0.4%; Re: 0.02-0.04%; Cu: 0.7-1.1%, and the balance is Fe and inevitable impurities. The wear-resistant steel ball prepared by the invention, which is based on chromium and carbon as raw materials, and is supplemented by the ratio of metal raw materials such as tungsten, manganese, and niobium, and the wear-resistant steel ball forged by the forging process, has good high hardness, high impact resistance, and high toughness performance, and can effectively improve the consistency of hardness, wear resistance, and smoothness of the surface and inside of the steel ball, making it suitable for various fields and can be better promoted and used. Chinese invention patent CN115354208A also discloses a high-chromium alloy composite wear-resistant steel ball, which is prepared by the following method: ordinary scrap steel, carburizer, ferrochrome, ferromanganese, ferroboron, ferromolybdenum, ferrosilicon, copper plate, metal nickel and metal aluminum are added to a smelting furnace to melt into molten iron, and the chemical composition and mass fraction of the molten iron are controlled to be: 2.0-3.0% C, 0.4-1.0% Si, 17-21% Cr, 0.5-1.0% Mn, 0.4-0.8% B, 0. 1-0.3% Mo, 0.5-1.0% Cu, 0.05-0.2% Ni, 0.05-0.1% Al, S≤0.05%, P≤0.05%, and the balance is Fe; when the temperature of the molten iron drops to 1530-1560℃, it is taken out of the furnace, and the inoculant is added to the molten iron for inoculation treatment. After standing and slag removal, a casting liquid is obtained; the casting liquid is poured into a mold, cast to form a spherical casting, and after quenching and tempering, the high-chromium alloy composite wear-resistant steel ball is obtained. The invention proposes a high-chromium alloy composite wear-resistant steel ball, which has excellent wear resistance and high toughness by effectively designing the composition of the wear-resistant steel ball, thereby further extending the service life of the wear-resistant steel ball. Chinese invention patent CN114892086A also discloses a corrosion-resistant, high-strength, wear-resistant steel ball, which is prepared by the following method: smelting target molten steel, the composition of the target molten steel includes C0.65-0.80%, Si0.40-0.85%, Mn0.65-0.95%, Cr0.40-1.00%, Mo0.04-0.06%, Ti0.02-0.04%, Cu0.04-0.08%, S≤0.020%, P≤0.020%, and the balance is Fe and inevitable impurities; casting to form a cast billet; rolling to form a steel ball billet; cooling and heat treatment to form a steel ball, which is the wear-resistant steel ball.The invention proposes a corrosion-resistant, high-strength, wear-resistant steel ball. By designing the composition of the wear-resistant steel ball and adjusting the production process of the wear-resistant steel ball, the wear-resistant steel ball has excellent wear resistance and high toughness, and further improves the corrosion resistance of the steel ball. Chinese invention patent CN113953426A also discloses a high-strength, high-toughness, wear-resistant steel ball steel and its preparation method, which belongs to the technical field of wear-resistant steel ball steel, and solves the problem that the strength and toughness of existing wear-resistant steel ball steel cannot meet the requirements at the same time and the uniformity is poor. The composition of the steel for wear-resistant steel balls is calculated by mass percentage as follows: C: 0.60%-0.70%, Si: 1.50%-1.80%, Mn: 0.92%-1.2%, Cr: 1.30%-2.00%, Mo: 0.01%-0.20%, Ni: 0.25%-0.60%, Al: 0.01%-0.05%, Cu: 0.05%-0.10%, V: 0.01%-0.20%, S≤0.03%, P: 0.01%-0.02%, and the rest is Fe and inevitable trace impurities, wherein (Mo+V)≥0.08%. The preparation method comprises the following steps: smelting molten steel, then casting to obtain an ingot; forging the ingot to obtain a billet; quenching and tempering the billet or quenching and partitioning the billet. The high-strength and high-toughness wear-resistant steel ball of the invention has good strength and toughness, good uniformity and a wide range of applications. Chinese invention patent CN104532139A also discloses a high-strength and high-toughness steel ball and a production method thereof. The high-strength and toughness steel ball contains 0.15%-0.3% C, 1.3-2.0% Si, 1.5%-2.5% Mn, 0.5%-1.0% Cr, 0.2-0.5% Mo, and the balance is Fe and inevitable impurities, in terms of weight percentage. The preparation method comprises the following steps: smelting molten steel; casting to form a continuous casting billet; heating the billet and then rolling: the continuous casting billet is heated to 1150-1300°C and kept warm for 1-4h before rolling to form a steel ball billet; the steel ball billet is heated to 1100-1250°C and kept warm for 10-60s, and then forged into a steel ball with a desired cross-section, with a final forging temperature of 900-1050°C; the forged steel ball is air-cooled to a surface temperature of 750-850°C, and then quenched in water, and when the surface temperature of the steel ball drops to 60-80°C, it is taken out and quickly tempered, and then degreased and finished to obtain a steel ball. The obtained steel ball has high hardness and good impact toughness. Chinese invention patent CN102418044A also discloses a steel for steel ball and a method for manufacturing the steel ball.The method for manufacturing a steel ball comprises the following steps: smelting molten steel; treating the molten steel with an off-furnace refining process, wherein the obtained molten steel is composed of 0.90% to 1.00% C, 0.30% to 1.00% Si, 0.80% to 1.20% Mn, 0.40% to 0.70% Cr, 0.01% to 0.05% Ti, not more than 0.025% P, not more than 0.025% S, not more than 2.0ppm [H], the balance Fe and inevitable impurities by weight percentage; casting; rolling; cutting to form a steel ball blank; heating the steel ball blank and then forging; quenching, tempering, followed by air cooling and finishing treatment to obtain a steel ball. The steel ball of the invention has high wear resistance, good strength and toughness, does not lose roundness during use, and has a long service life. Chinese invention patent CN102443741A also discloses a steel ball for a ball mill and a manufacturing method thereof. The method for manufacturing ball mill steel balls comprises the following steps: smelting molten steel; treating the molten steel with an off-furnace refining process, wherein the obtained molten steel is composed of 0.90% to 1.00% C, 0.30% to 1.00% Si, 0.80% to 1.20% Mn, 0.40% to 0.70% Cr, 0.01% to 0.05% Ti, not more than 0.025% P, not more than 0.025% S, the balance Fe and inevitable impurities by weight percentage; casting; rolling; cutting to form a steel ball blank; heating the steel ball blank and then forging; quenching, tempering, followed by air cooling and finishing treatment to obtain a steel ball. The ball mill steel ball of the invention has high wear resistance, good strength and toughness, does not lose roundness during use, and has a long service life. Although the steel balls obtained by the above method have improved strength and toughness, they generally have the disadvantages of low hardness and poor wear resistance. Summary of the invention

[0007] The present invention obtains a martensite-bainite-austenite complex phase structure by changing the alloy element design in the steel and optimizing the heat treatment process, so that the wear-resistant steel ball has high hardness and excellent work hardening effect while maintaining high strength and toughness, thereby significantly improving the wear resistance of the steel ball.

[0008] A high-strength and wear-resistant steel ball and a preparation method thereof, the specific preparation process steps are:

[0009] ① Use medium frequency induction furnace to melt molten steel, with scrap steel, carburizer, ferrochrome, ferrosilicon, metallic aluminum and ferromanganese nitride as main furnace materials; firstly, mix scrap steel, carburizer and ferrochrome and heat to melt, add ferrosilicon and metallic aluminum in sequence after the molten steel is melted, and control the chemical composition and mass fraction of the molten steel in the furnace to 1.22-1.37% C, 2.15-2.33% Si, 0.84-0.97% Al, 2.13-2.38% Cr, ≤0.80% Mn, <0.040% S, <0.045% P, the remainder is Fe and inevitable impurities; then heat the molten steel to 1623-1646℃, and add ferromanganese nitride preheated at 720-780℃ for 200-230 minutes , the amount of ferromanganese nitride added accounts for 7.5-7.8% of the mass fraction of the molten steel in the furnace; after the ferromanganese nitride is completely melted, it is kept warm for 4-6 minutes, and then the molten steel is taken out of the furnace into the ladle; aluminum-magnesium multi-component alloy blocks are pre-placed at the bottom of the ladle, and the particle size of the aluminum-magnesium multi-component alloy blocks is 4-8mm; the amount of aluminum-magnesium multi-component alloy blocks added accounts for 0.40-0.45% of the mass fraction of the molten steel entering the ladle; the chemical composition and mass fraction of the aluminum-magnesium multi-component alloy blocks are: 4.17-4.72% Mg, 18.62-19.20% Si, 5.61-5.95% Ca, 2.62-2.96% Ce, 3.14-3.55% K, 1.57-1.93% B, and the balance is Al and unavoidable impurities;

[0010] ② Step ① After the molten steel in the ladle is deslagging and standing, when the temperature drops to 1518-1533° C., the molten steel is poured into a round steel bar with a diameter of φ90-100 mm on a continuous casting machine, and the round steel bar is cut into a length of 6-8 m; then the round steel bar with a length of 6-8 m is placed in a heating furnace for heating, and after the round steel bar is evenly heated to 1180-1250° C. and kept warm for 45-60 minutes, the round steel bar is transported to a continuous cutting machine through a steel bar conveying device with a heat preservation device for cutting to obtain a steel segment, and the length of the steel segment is controlled to be 180-225 mm; then the steel segment is forged into a steel ball, and the final forging temperature is controlled to be 940-1020° C.;

[0011] ③ When the surface temperature of the steel ball after forging in step ② is 940-1020° C., directly quench the steel ball in hot water at a temperature of 55-80° C. for 35-45 seconds, then take the steel ball out of the hot water, and continue to quench the steel ball quenched by hot water in a quenching liquid at a temperature of 22-40° C. for 8-10 minutes; the quenching liquid is composed of 46-48% by mass of Na2SiO3, 5.5-6.0% by mass of NaOH and 46.5-48% by mass of H2O;

[0012] ④ After the steel ball quenched by the quenching liquid in step ③ is reheated to 180-195°C and kept warm for 14-15 hours, the furnace is cooled to a temperature below 120°C, and the steel ball is air-cooled to room temperature to obtain a high-strength, tough and wear-resistant steel ball.

[0013] As mentioned above, the chemical composition and mass fraction of ferromanganese nitride are: 74.83-75.57% Mn, 4.16-4.30% N, <0.5% C, <3.5% Si, <0.3% P, <0.02% S, and the remainder is Fe and unavoidable impurities.

[0014] In order to improve the strength and wear resistance of the wear-resistant steel ball, the present invention adds cheap alloy elements such as aluminum, silicon, and manganese to the steel, and optimizes the heat treatment process to obtain a martensite-bainite-austenite complex phase structure, so that the wear-resistant steel ball has high hardness and excellent work hardening effect while maintaining high strength and toughness, thereby significantly improving the wear resistance of the steel ball. A high-strength and tough wear-resistant steel ball and a preparation method thereof, the specific preparation process steps are:

[0015] First, a medium frequency induction furnace is used to melt molten steel, with scrap steel, carburizer, ferrochrome, ferrosilicon, metallic aluminum and ferromanganese nitride as the main furnace materials. The medium frequency induction furnace is used to melt molten steel, and the smelting process is simple and the alloy element recovery rate is high. The present invention uses scrap steel, carburizer, ferrochrome, ferrosilicon, metallic aluminum and ferromanganese nitride as the main furnace materials, and does not contain expensive alloy elements such as molybdenum, nickel, tungsten, vanadium, niobium, etc., ensuring that the raw material cost of wear-resistant steel balls is low. The present invention first mixes scrap steel, a carburizer and ferrochrome for heating and melting, and then sequentially adds ferrosilicon and metallic aluminum after the molten steel is melted, and controls the chemical composition and mass fraction of the molten steel in the furnace to be 1.22-1.37% C, 2.15-2.33% Si, 0.84-0.97% Al, 2.13-2.38% Cr, ≤0.80% Mn, <0.040% S, <0.045% P, and the remainder is Fe and inevitable impurities. The silicon content in the steel of the present invention is as high as 2.15-2.33% Si, and the solubility of silicon in cementite is extremely low and can effectively inhibit the precipitation of carbides. Since the solubility of carbon in ferrite is very low, the adjacent austenite is carbon-rich, and the carbon-rich austenite can exist stably at room temperature. Therefore, adding more silicon elements can promote the generation of more residual austenite in the quenching structure, and improve the plasticity and toughness of the steel. In addition, the retained austenite undergoes work hardening under the action of impact wear, which can further improve the wear resistance of the steel ball. However, the amount of retained austenite cannot be too much. Too much retained austenite will reduce the hardness and wear resistance of the steel. In addition, too much retained austenite will cause the wear-resistant steel ball to peel off and crack during use, which will reduce the service life of the steel ball. The present invention controls the aluminum content and the silicon content to ensure that the volume fraction of retained austenite in the quenching structure of the wear-resistant steel ball is controlled at 6-10%, which has excellent use effect.

[0016] The present invention heats molten steel to 1623-1646°C, and adds ferromanganese nitride preheated at 720-780°C for 200-230 minutes, wherein the chemical composition and mass fraction of the ferromanganese nitride are: 74.83-75.57% Mn, 4.16-4.30% N, <0.5% C, <3.5% Si, <0.3% P, <0.02% S, and the remainder is Fe and inevitable impurities. The amount of ferromanganese nitride added accounts for 7.5-7.8% of the mass fraction of the molten steel in the furnace. After the ferromanganese nitride is completely melted, it is kept warm for 4-6 minutes, and then the molten steel is discharged from the furnace into a ladle. The nitrogen element in the ferromanganese nitride is easily combined with the aluminum element in the steel to generate aluminum nitride with very high thermal stability, and the hardness of the aluminum nitride is generally 1800-2200 HV. The high-hardness aluminum nitride generated in situ in the steel can significantly improve the hardness and wear resistance of the wear-resistant steel ball. In addition to its high hardness, aluminum nitride also has many other excellent properties. For example, its melting point is 2200℃ and boiling point is 2517℃, which can ensure that high-hardness aluminum nitride can be stable during subsequent forging and heat treatment processes.

[0017] The present invention pre-places aluminum-magnesium multi-component alloy blocks at the bottom of the ladle, and the particle size of the aluminum-magnesium multi-component alloy blocks is 4-8 mm; the amount of the aluminum-magnesium multi-component alloy blocks added accounts for 0.40-0.45% of the mass fraction of the molten steel entering the ladle. The chemical composition and mass fraction of the aluminum-magnesium multi-component alloy blocks are: 4.17-4.72% Mg, 18.62-19.20% Si, 5.61-5.95% Ca, 2.62-2.96% Ce, 3.14-3.55% K, 1.57-1.93% B, and the remainder is Al and inevitable impurities. The added aluminum-magnesium multi-component alloy blocks contain 1.57-1.93% B, which can significantly improve the hardenability of the steel and is also conducive to obtaining a bainite structure with excellent performance in the quenching structure. In addition, the silicon and manganese contents in the material of the present invention are high, and the casting solidification structure is coarse. The aluminum-magnesium multi-element alloy block added by the present invention contains 2.62-2.96% Ce, 3.14-3.55% K and 4.17-4.72% Mg, which can promote the significant refinement of the solidification structure. In addition, the addition of 4.17-4.72% Mg, due to the low melting point and boiling point of magnesium element, the melting point is 648.8°C. The boiling point is 1107°C, and it is easy to gasify when added to molten steel, which promotes the tumbling of molten steel in the ladle, and is conducive to the uniform distribution of low-density boron elements and aluminum nitride in the steel. The aluminum-magnesium multi-element alloy block contains 5.61-5.95% Ca, which is conducive to improving the morphology and distribution of inclusions in steel, thereby improving the strength and toughness of steel.

[0018] After the molten steel in the ladle of the present invention is slag-stripped and left to stand, when the temperature drops to 1518-1533°C, the molten steel is poured into a round steel bar with a diameter of φ90-100mm on a continuous casting machine, and the length of the round steel bar is cut into 6-8m; then the round steel bar with a length of 6-8m is placed in a heating furnace for heating, and after the round steel bar is evenly heated to 1180-1250°C and kept warm for 45-60 minutes, the round steel bar is completely austenitized, which is beneficial to subsequent forging processing. The round steel bar is transported to a continuous cutting machine through a steel bar conveying device with a heat preservation device for cutting to obtain a steel section, and the length of the steel section is controlled to be 180-225mm; then the steel section is forged into a steel ball, and the final forging temperature is controlled to be 940-1020°C. When the surface temperature of the forged steel ball is 940-1020°C, the steel ball is directly quenched and cooled in hot water at a temperature of 55-80°C for 35-45 seconds. This ensures that the steel ball does not have low-hardness pearlite structure. If the steel ball is cooled in hot water for too long, it is very easy to crack due to the high carbon content of the steel ball.

[0019] The present invention then takes the steel ball out of the hot water, and continues to quench and cool the steel ball quenched by the hot water in a quenching liquid at a temperature of 22-40°C for 8-10 minutes; the quenching liquid is composed of 46-48% by mass of Na2SiO3, 5.5-6.0% of NaOH and 46.5-48% of H2O. After quenching and cooling in the quenching liquid of 46-48% by mass of Na2SiO3, 5.5-6.0% of NaOH and 46.5-48% of H2O for 8-10 minutes, it can be ensured that a bainite matrix structure with excellent performance of up to 65-72% by volume fraction is obtained in the quenched structure. The quenching liquid of the present invention is simple to operate and has high safety. As an environmentally friendly quenching liquid, the quenching liquid of the present invention has a relatively low cost, does not cause pollution to the environment, and has better economy. After the steel ball quenched by the quenching liquid is reheated to 180-195°C and kept warm for 14-15 hours, the internal stress of the steel ball can be removed and the structure can be stabilized. Finally, the furnace is cooled to a temperature below 120°C, and air-cooled to room temperature to obtain high-strength, tough and wear-resistant steel balls.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1. The wear-resistant steel ball of the present invention uses cheap silicon, manganese and aluminum as main alloy elements, does not contain expensive alloy elements such as molybdenum, nickel, niobium, tungsten and vanadium, and has a lower production cost.

[0022] 2. The steel ball matrix of the present invention contains 65-72% of bainite matrix with excellent performance and 6-10% of retained austenite, and the rest of the matrix is ​​high-strength martensite. In addition, the steel ball also contains high-hardness aluminum nitride wear-resistant hard phase, ensuring that the tensile strength of the wear-resistant steel ball is ≥2200MPa, the surface hardness is ≥62HRC, the core hardness is ≥61HRC, and the impact toughness is ≥50J / cm 2 , the difference between surface hardness and core hardness is less than 1.5HRC.

[0023] 3. The wear-resistant steel ball of the present invention has a good work hardening effect. When used on a Φ10.36×5.49m iron ore semi-autogenous grinding mill, the surface hardness of the grinding ball is increased by 2.5-3.0HRC, and the grinding ball consumption is about 520 grams per ton of ore. Compared with the current commonly used grinding balls, which consume 910 grams per ton of ore, the consumption of grinding balls is greatly reduced, which significantly reduces the waste of metal materials and reduces production costs, and has good economic and social benefits. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with examples, but the present invention is not limited to the following examples.

[0025] Embodiment 1:

[0026] A high-strength and wear-resistant steel ball and a preparation method thereof, using a 5000 kg medium-frequency induction furnace to melt molten steel, the specific preparation process steps are:

[0027] ① A 5000 kg medium frequency induction furnace is used to melt molten steel, with scrap steel, carburizer, ferrochrome, ferrosilicon, metallic aluminum and ferromanganese nitride as the main furnace materials; firstly, the scrap steel, carburizer and ferrochrome are mixed and heated to melt, and after the molten steel is melted, ferrosilicon and metallic aluminum are added in sequence, and the chemical structure and mass fraction of the molten steel in the furnace are controlled to be 1.22% C, 2.33% Si, 0.84% ​​Al, 2.38% Cr, 0.54% Mn, 0.037% S, 0.042% P, and the balance is Fe and unavoidable impurities; then the molten steel is heated to 1623°C, and ferromanganese nitride preheated at 720°C for 230 minutes is added (the chemical composition and mass fraction of the ferromanganese nitride are: 74.83% Mn, 4.30% N, 0.29% C, 2.17% Si, 0.16% P, 0.011% S, the balance is Fe and inevitable impurities), the amount of ferromanganese nitride added accounts for 7.5% of the mass fraction of the molten steel in the furnace; after the ferromanganese nitride is completely melted, it is kept warm for 4 minutes, and then the molten steel is taken out of the furnace into the ladle; an aluminum-magnesium multi-element alloy block is pre-placed at the bottom of the ladle, and the particle size of the aluminum-magnesium multi-element alloy block is 4-8mm; the amount of the aluminum-magnesium multi-element alloy block added accounts for 0.40% of the mass fraction of the molten steel entering the ladle; the chemical composition and mass fraction of the aluminum-magnesium multi-element alloy block are: 4.17% Mg, 19.20% Si, 5.61% Ca, 2.96% Ce, 3.14% K, 1.93% B, the balance is Al and inevitable impurities;

[0028] ② Step ① After the molten steel in the ladle is deslagging and standing, when the temperature drops to 1518° C., the molten steel is poured into a round steel bar with a diameter of φ95 mm on a continuous casting machine, and the round steel bar is cut into 8 m in length; then the round steel bar with a length of 8 m is placed in a walking-beam natural gas heating furnace for heating, and after the round steel bar is evenly heated to 1250° C. and kept warm for 45 minutes, the round steel bar is transported to a continuous cutting machine through a steel bar conveying device with a heat preservation device for cutting to obtain a steel segment, and the length of the steel segment is controlled at 202.7 mm; then the steel segment is forged into a φ140 mm steel ball, and the final forging temperature is controlled at 970-1000° C.;

[0029] ③ When the surface temperature of the steel ball after forging in step ② is 970-1000°C, directly quench the steel ball in hot water at a temperature of 80°C for 45 seconds, then take the steel ball out of the hot water, and continue to quench the steel ball quenched by hot water in a quenching liquid at a temperature of 40°C for 10 minutes; the quenching liquid is composed of 47% by mass of Na2SiO3, 5.5% by mass of NaOH and 47.5% by mass of H2O;

[0030] ④ After the steel ball quenched by the quenching liquid in step ③ is reheated to 195°C and kept at this temperature for 14 hours, the furnace is cooled to a temperature below 120°C, and the steel ball is air-cooled to room temperature after being taken out of the furnace to obtain a high-strength and wear-resistant steel ball. The mechanical properties of the wear-resistant steel ball are shown in Table 1.

[0031] Embodiment 2:

[0032] A high-strength and wear-resistant steel ball and a preparation method thereof, using a 7500 kg medium-frequency induction furnace to melt molten steel, the specific preparation process steps are:

[0033] ① A 7500 kg medium frequency induction furnace is used to melt molten steel, with scrap steel, carburizer, ferrochrome, ferrosilicon, metallic aluminum and ferromanganese nitride as the main furnace materials; firstly, the scrap steel, carburizer and ferrochrome are mixed and heated to melt, and after the molten steel is melted, ferrosilicon and metallic aluminum are added in sequence, and the chemical structure and mass fraction of the molten steel in the furnace are controlled to be 1.37% C, 2.15% Si, 0.97% Al, 2.13% Cr, 0.75% Mn, 0.029% S, 0.040% P, and the balance is Fe and unavoidable impurities; then the molten steel is heated to 1646°C, and ferromanganese nitride preheated at 780°C for 200 minutes is added (the chemical composition and mass fraction of the ferromanganese nitride are: 75.57% Mn, 4.16% N, 0.22% C, 3.08% Si, 0.11% P, 0.017% S, the balance is Fe and inevitable impurities), the amount of ferromanganese nitride added accounts for 7.8% of the mass fraction of the molten steel in the furnace; after the ferromanganese nitride is completely melted, it is kept warm for 6 minutes, and then the molten steel is taken out of the furnace into the ladle; an aluminum-magnesium multi-element alloy block is pre-placed at the bottom of the ladle, and the particle size of the aluminum-magnesium multi-element alloy block is 4-8mm; the amount of the aluminum-magnesium multi-element alloy block added accounts for 0.45% of the mass fraction of the molten steel entering the ladle; the chemical composition and mass fraction of the aluminum-magnesium multi-element alloy block are: 4.72% Mg, 18.62% Si, 5.95% Ca, 2.62% Ce, 3.55% K, 1.57% B, the balance is Al and inevitable impurities;

[0034] ② Step ① After the molten steel in the ladle is deslagging and standing, when the temperature drops to 1533° C., the molten steel is poured into a round steel bar with a diameter of φ90 mm on a continuous casting machine, and the round steel bar is cut into 6 m in length; then the round steel bar with a length of 6 m is placed in a resistance heating furnace for heating, and after the round steel bar is evenly heated to 1180° C. and kept warm for 60 minutes, the round steel bar is transported to a continuous cutting machine through a steel bar conveying device with a heat preservation device for cutting to obtain a steel segment, and the length of the steel segment is controlled at 180.8 mm; then the steel segment is forged into a φ130 mm steel ball, and the final forging temperature is controlled at 940-990° C.;

[0035] ③ When the surface temperature of the steel ball after forging in step ② is 940-990°C, directly quench the steel ball in hot water at a temperature of 55°C for 35 seconds, then take the steel ball out of the hot water, and continue to quench the steel ball quenched by hot water in a quenching liquid at a temperature of 22°C for 8 minutes; the quenching liquid is composed of 46% by mass of Na2SiO3, 6.0% by mass of NaOH and 48% by mass of H2O;

[0036] ④ After the steel ball quenched by the quenching liquid in step ③ is reheated to 180°C and kept for 15 hours, the furnace is cooled to a temperature below 120°C, and the steel ball is air-cooled to room temperature to obtain a high-strength and wear-resistant steel ball. The mechanical properties of the wear-resistant steel ball are shown in Table 1.

[0037] Embodiment 3:

[0038] A high-strength and wear-resistant steel ball and a preparation method thereof, using a 10,000 kg medium-frequency induction furnace to melt molten steel, the specific preparation process steps are:

[0039] ① A 10,000 kg medium frequency induction furnace is used to melt molten steel, with scrap steel, carburizer, ferrochrome, ferrosilicon, metallic aluminum and ferromanganese nitride as the main furnace materials; firstly, the scrap steel, carburizer and ferrochrome are mixed and heated to melt, and after the molten steel is melted, ferrosilicon and metallic aluminum are added in sequence, and the chemical structure and mass fraction of the molten steel in the furnace are controlled to be 1.28% C, 2.26% Si, 0.88% Al, 2.29% Cr, 0.61% Mn, 0.036% S, 0.044% P, and the balance is Fe and unavoidable impurities; then the molten steel is heated to 1635° C., and ferromanganese nitride preheated at 750° C. for 210 minutes is added (the chemical composition and mass fraction of the ferromanganese nitride are: 75.06% Mn, 4.23% N, 0.39% C, 1.82% Si, 0.13% P, 0.017% S, the balance is Fe and inevitable impurities), the amount of ferromanganese nitride added accounts for 7.6% of the mass fraction of the molten steel in the furnace; after all the ferromanganese nitride is melted, it is kept warm for 5 minutes, and then the molten steel is taken out of the furnace into the ladle; aluminum-magnesium multi-component alloy blocks are pre-placed at the bottom of the ladle, and the particle size of the aluminum-magnesium multi-component alloy blocks is 4-8mm; the amount of aluminum-magnesium multi-component alloy blocks added accounts for 0.42% of the mass fraction of the molten steel entering the ladle; the chemical composition and mass fraction of the aluminum-magnesium multi-component alloy blocks are: 4.61% Mg, 18.94% Si, 5.80% Ca, 2.77% Ce, 3.36% K, 1.83% B, the balance is Al and inevitable impurities;

[0040] ② Step ① After the molten steel in the ladle is deslagging and standing, when the temperature drops to 1527°C, the molten steel is poured into a round steel bar with a diameter of φ100mm on a continuous casting machine, and the round steel bar is cut into a length of 7m; then the round steel bar with a length of 7m is placed in a walking-beam natural gas heating furnace for heating, and after the round steel bar is evenly heated to 1220°C and kept warm for 50 minutes, the round steel bar is transported to a continuous cutting machine through a steel bar conveying device with a heat preservation device for cutting to obtain a steel segment, and the length of the steel segment is controlled at 225mm; then the steel segment is forged into a φ150mm steel ball, and the final forging temperature is controlled at 990-1020°C;

[0041] ③ When the surface temperature of the steel ball after forging in step ② is 990-1020°C, directly quench the steel ball in hot water at a temperature of 70°C for 40 seconds, then take the steel ball out of the hot water, and continue to quench the steel ball quenched by hot water in a quenching liquid at a temperature of 31°C for 9 minutes; the quenching liquid is composed of 48% by mass of Na2SiO3, 5.5% by mass of NaOH and 46.5% by mass of H2O;

[0042] ④ After the steel ball quenched by the quenching liquid in step ③ is reheated to 190°C and kept at this temperature for 14.5 hours, the furnace is cooled to a temperature below 120°C, and the steel ball is air-cooled to room temperature after being taken out of the furnace to obtain a high-strength and wear-resistant steel ball. The mechanical properties of the wear-resistant steel ball are shown in Table 1.

[0043] Table 1 Mechanical properties of high-strength and wear-resistant steel balls

[0044]

[0045] The wear-resistant steel ball of the present invention uses cheap silicon, manganese and aluminum as main alloying elements, and does not contain expensive alloying elements such as molybdenum, nickel, niobium, tungsten and vanadium, and has low production cost and good prospects for promotion and application. The matrix structure of the steel ball of the present invention contains a bainite matrix structure with excellent performance and 6-10% residual austenite with a volume fraction of up to 65-72%, and the remaining matrix structure is high-strength martensite. In addition, the steel ball also contains a high-hardness aluminum nitride wear-resistant hard phase, which ensures that the tensile strength of the wear-resistant steel ball is ≥2200MPa, the surface hardness is ≥62HRC, the core hardness is ≥61HRC, and the impact toughness is ≥50J / cm 2 , the difference between the surface hardness and the core hardness is less than 1.5HRC. The wear-resistant steel ball of the present invention has a good work hardening effect. When used on a Φ10.36×5.49m iron ore semi-autogenous mill, the surface hardness of the grinding ball is increased by 2.5-3.0HRC. The steel ball of the present invention does not lose its roundness, break, or peel off during use. The consumption of grinding balls is about 520 grams per ton of ore. Compared with the current commonly used grinding balls, which consume 910 grams per ton of ore, the consumption of grinding balls is significantly reduced, which significantly reduces the consumption of metal materials and reduces production costs. The promotion and application of the steel ball has good economic and social benefits.

Claims

1. A method for preparing a high-strength and wear-resistant steel ball, characterized in that: The molten steel is melted in a medium frequency induction furnace and the forged steel balls are used. The specific preparation process steps include the following: ① Use medium frequency induction furnace to melt molten steel, with scrap steel, carburizer, ferrochrome, ferrosilicon, metallic aluminum and ferromanganese nitride as main furnace materials; firstly, mix scrap steel, carburizer and ferrochrome and heat to melt, add ferrosilicon and metallic aluminum in turn after the molten steel is melted, and control the chemical composition and mass fraction of the molten steel in the furnace to 1.22-1.37% C, 2.15-2.33% Si, 0.84-0.97% Al, 2.13-2.38% Cr, ≤0.80% Mn, <0.040% S, <0.045% P, the remainder is Fe and unavoidable impurities; then heat the molten steel to 1623-1646℃, and add ferromanganese nitride preheated at 720-780℃ for 200-230 minutes , the amount of ferromanganese nitride added accounts for 7.5-7.8% of the mass fraction of the molten steel in the furnace; after the ferromanganese nitride is completely melted, it is kept warm for 4-6 minutes, and then the molten steel is taken out of the furnace into the ladle; aluminum-magnesium multi-component alloy blocks are pre-placed at the bottom of the ladle, and the particle size of the aluminum-magnesium multi-component alloy blocks is 4-8mm; the amount of aluminum-magnesium multi-component alloy blocks added accounts for 0.40-0.45% of the mass fraction of the molten steel entering the ladle; the chemical composition and mass fraction of the aluminum-magnesium multi-component alloy blocks are: 4.17-4.72% Mg, 18.62-19.20% Si, 5.61-5.95% Ca, 2.62-2.96% Ce, 3.14-3.55% K, 1.57-1.93% B, and the balance is Al and unavoidable impurities; ② Step ① After the molten steel in the ladle is deslagging and standing, when the temperature drops to 1518-1533° C., the molten steel is poured into a round steel bar with a diameter of φ90-100 mm on a continuous casting machine, and the round steel bar is cut into a length of 6-8 m; then the round steel bar with a length of 6-8 m is placed in a heating furnace for heating, and after the round steel bar is evenly heated to 1180-1250° C. and kept warm for 45-60 minutes, the round steel bar is transported to a continuous cutting machine through a steel bar conveying device with a heat preservation device for cutting to obtain a steel segment, and the length of the steel segment is controlled to be 180-225 mm; then the steel segment is forged into a steel ball, and the final forging temperature is controlled to be 940-1020° C.; ③ When the surface temperature of the steel ball after forging in step ② is 940-1020° C., directly quench the steel ball in hot water at a temperature of 55-80° C. for 35-45 seconds, then take the steel ball out of the hot water, and continue to quench the steel ball quenched by hot water in a quenching liquid at a temperature of 22-40° C. for 8-10 minutes; the quenching liquid is composed of 46-48% by mass of Na2SiO3, 5.5-6.0% by mass of NaOH and 46.5-48% by mass of H2O; ④ After the steel ball quenched by the quenching liquid in step ③ is reheated to 180-195°C and kept warm for 14-15 hours, the furnace is cooled to a temperature below 120°C, and the steel ball is air-cooled to room temperature after being taken out of the furnace to obtain a high-strength, tough and wear-resistant steel ball.

2. The method for preparing a high-strength and wear-resistant steel ball according to claim 1, characterized in that: The chemical composition and mass fraction of the nitride manganese iron are: 74.83-75.57% Mn, 4.16-4.30% N, <0.5% C, <3.5% Si, <0.3% P, <0.02% S, and the remainder is Fe and unavoidable impurities.

3. A high-strength, tough and wear-resistant steel ball prepared according to the method of claim 1 or 2.

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