Forged wear-resistant steel ball for semi-autogenous grinding and preparation method of forged wear-resistant steel ball

Abstract

The invention relates to the technical field of wear-resistant materials, in particular to a semi-autogenous-grinding forged wear-resistant steel ball and a preparation method thereof.The semi-autogenous-grinding forged wear-resistant steel ball comprises, by mass, 0.75%-0.85% of C, 2.1%-3.2% of V + Mn, 1.8%-2.2% of Cr, 0.25%-0.45% of Mo, 0.15%-0.35% of Ni, 0.25%-0.4% of Cu, 0.04%-0.08% of Nb, 0.01%-0.06% of Ti, 0.003%-0.008% of B, smaller than or equal to 0.021% of P, smaller than or equal to 0.020% of S and the balance Fe and inevitable impurities. And the steel ball blank is subjected to heating forging, quenching, tempering treatment and natural cooling, and then the wear-resistant steel ball is obtained. The prepared wear-resistant steel ball is high in surface and core hardness, high in impact energy, remarkably improved in wear resistance and good in hardness uniformity.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of wear-resistant materials, in particular to a forged wear-resistant steel ball for semi-autogenous grinding and a preparation method thereof. BACKGROUND

[0002] In today's industrial production, wear-resistant steel balls, as key wear-resistant components, play a crucial role in many fields. Especially in the metallurgical, mineral processing, building materials, and power industries, large-size grinding balls for semi-autogenous grinding of material crushing and grinding are used. The demand for material processing in these industries continues to grow, and the performance requirements for wear-resistant steel balls are becoming increasingly stringent. Currently, the production process of commonly used wear-resistant steel balls on the market mostly utilizes post-forging residual heat quenching. Although this process has the advantage of low production cost, the martensite structure of the steel balls produced by this process is coarse and unevenly distributed after quenching, resulting in low hardness and toughness of the steel balls. When facing high-hardness ores, the breakage rate of the steel balls will significantly increase. In particular, after the emergence of wet-type large semi-autogenous grinding machines, higher performance requirements are placed on the grinding balls. Not only do they need to have good anti-breakage performance and wear resistance, but they also need to have certain corrosion resistance. In addition, current wear-resistant steel balls are difficult to balance high hardness and high impact toughness, and the steel balls produced by existing forging equipment lack flatness, affecting the grinding efficiency. Based on the above statements, there is an urgent need to develop a forged wear-resistant steel ball for semi-autogenous grinding with low cost, corrosion resistance, high wear resistance, and good toughness, as well as a preparation method thereof, to improve the working efficiency of semi-autogenous grinding machines, reduce the cost of grinding ores, and meet the development needs of industrial production. SUMMARY

[0003] To solve the technical problems mentioned in the background art, the application provides a forged wear-resistant steel ball for semi-autogenous grinding.

[0004] The application provides a forged wear-resistant steel ball for semi-autogenous grinding, which adopts the following technical solutions: A forged wear-resistant steel ball for semi-autogenous grinding, by mass percentage, the chemical composition includes: C: 0.75-0.85%, V+Mn: 2.1-3.2%, Cr: 1.8-2.2%, Mo: 0.25-0.45%, Ni: 0.15-0.35%, Cu: 0.25-0.4%, Nb: 0.04-0.08%, Ti: 0.01-0.06%, B: 0.003-0.008%, P≤0.021%, S≤0.020%, and the balance is Fe and unavoidable impurities. Preferably, the chemical composition also satisfies the quantitative relationship: [C] / ([Nb]+[Ti])≥6.2, [Cr]+[Mo]≥2.2%; [Ni]+[Cu]≥0.5%; wherein [C], [Nb], [Ti], [Cr], [Mo], [Ni], [Cu] are the mass percentage contents of C, Nb, Ti, Cr, Mo, Ni, Cu respectively.

[0005] Preferably, the mass ratio of V and Mn in the chemical composition is 5-8:3-6.

[0006] The application also provides a preparation method of the forged wear-resistant steel ball for semi-autogenous grinding. Step 1, low-titanium pig iron, scrap steel and alloy materials are added into a vacuum induction furnace for smelting, and the contents of C, V, Mn, Cr, Mo, Ni, Cu, Nb, Ti, B, P and S are adjusted after inspection; after deoxidation, desulfurization and slag removal, molten steel is obtained; Step 2, the molten steel is cast into a shape, and after the alloy melt solidifies, the mold is opened, and the steel ball embryo is taken out and air-cooled to room temperature; Step 3, the steel ball embryo is forged by three-stage heating, and then spray quenching is performed, and after quenching for 1-2 hours, low-temperature tempering treatment is performed, and after natural cooling, the forged wear-resistant steel ball for semi-autogenous grinding is obtained.

[0007] Preferably, the smelting temperature in step 1 is 1580-1620℃.

[0008] Preferably, the molten steel casting temperature in step 2 is 1500-1550℃.

[0009] Preferably, the three-stage heating forging process in step 3 is as follows: the temperature is increased from room temperature to 580-650℃ at a speed of ≤80℃ / h, the temperature is kept for 20-30min, the temperature is continuously increased to 800-950℃ at a speed of ≤120℃ / h, the temperature is kept for 30-50min, the temperature is continuously increased to 1050-1100℃ at a speed of ≤30℃ / h, and the temperature is kept for 1-2h.

[0010] Preferably, the spray quenching medium in step 3 is composed of PAG quenching liquid, PEG-400 and deionized water with a mass ratio of 5-8:1-2:100-120.

[0011] Preferably, the temperature of the spray quenching medium is 60-80℃.

[0012] Preferably, the spray quenching pressure in step 3 is 0.4-0.8Mpa.

[0013] Preferably, the low-temperature tempering treatment temperature in step 3 is 220-240℃, the temperature increasing speed is ≤30℃ / h, and the temperature is kept for 5-7h.

[0014] In summary, the present application has the following beneficial effects: In the process of preparing the wear-resistant steel ball, the ratio of [C] / ([Nb]+[Ti]) is strictly controlled, and the Nb, Ti and C form carbides, refine the grain and improve the wear resistance. The Nb and Ti formed carbides have high melting point and are dispersedly precipitated in the form of fine particles during the solidification of the steel liquid, which can effectively pin the grain boundary and hinder the growth of austenite grains. The hardness and toughness of the balanced matrix are balanced. By controlling the ratio between V and Mn, although Mn can improve the hardenability, excessive amount will promote the growth of austenite grains, resulting in the formation of coarse martensite after quenching, increasing the brittleness of the steel ball. In addition, Mn has a large segregation tendency, and high content can easily cause composition inhomogeneity and aggravate organizational defects. The V formed carbides are dispersedly precipitated in the form of fine particles during the solidification and heat treatment of the steel liquid, pinning the grain boundary and hindering the grain growth. The use of V fine-grain effect further improves the hardenability, reduces the hardness difference between the surface and the center, and the synergistic effect of the two can make the martensite transformation more uniform during quenching, reduce the phase transformation stress caused by different grain sizes, reduce the internal residual stress of the steel ball, and reduce the risk of quenching cracking.

[0015] In the calcination process of the wear-resistant steel ball, the temperature rising speed is controlled in sections to reduce the thermal expansion difference of the billet, prevent cracking before forging, ensure the uniformity of the structure, and use the PAG quenching liquid and PEG-400 to prepare a spray quenching medium. PEG-400 can adjust the viscosity of the medium to moderate the cooling speed, avoid cracks caused by too fast martensite transformation, and obtain a more uniform hardness distribution of the wear-resistant steel ball after quenching. A lower temperature rising speed is selected for tempering treatment to reduce the internal stress of quenching, retain the high hardness of martensite, and at the same time, improve the impact toughness and enhance the anti-fracture ability. The technical scheme significantly improves the performance of the steel ball through precise chemical composition ratio and process control. The optimized combination and proportion of alloy elements enhance the hardness and wear resistance of the steel ball, the reasonable temperature rising speed and quenching and tempering process make the internal structure of the steel ball uniform, and the steel ball has high strength and high toughness; the specific proportion of the quenching medium and the temperature improve the quenching efficiency and quality. The service life is effectively prolonged, the wear and failure risk is reduced, and the semi-autogenous grinding efficiency and economy are improved. DETAILED DESCRIPTION

[0016] The present application will be further described in detail below in combination with examples.

[0017] The PAG quenching liquid used in the examples and comparative examples of the present application is purchased from Zhengzhou Tonglin Lubricating Industry Co., Ltd., and PEG-400 is purchased from Taizhou Jiayin Chemical Co., Ltd.

[0018] Examples 1-3 provide a forged wear-resistant steel ball for semi-autogenous grinding and a preparation method thereof.

[0019] Example 1 A forged wear-resistant steel ball for semi-autogenous grinding, according to mass percentage, its chemical composition includes: C: 0.75%, V+Mn: 2.1%, Cr: 1.8%, Mo: 0.45%, Ni: 0.25%, Cu: 0.25%, Nb: 0.04%, Ti: 0.02%, B: 0.003%, P: 0.021%, S: 0.015%, and the balance is Fe and inevitable impurities, wherein the mass ratio of V and Mn in the chemical composition is 5:3.

[0020] A preparation method of a forged wear-resistant steel ball for semi-autogenous grinding, comprising the following preparation steps: Step 1, low-titanium pig iron, scrap steel and alloy materials are added into a vacuum induction furnace for smelting, the smelting temperature is 1580℃, the contents of C, V, Mn, Cr, Mo, Ni, Cu, Nb, Ti, B, P and S are adjusted after inspection, and after deoxidation, desulfurization and slag removal, molten steel is obtained; Step 2, the molten steel is poured into shape, the molten steel pouring forming temperature is 1500℃, the mold is opened after the alloy melt solidifies, and the steel ball blank is taken out and air-cooled to room temperature; Step 3, the steel ball blank is heated from room temperature to 580℃ at a heating rate of 80℃ / h, and then heated to 800℃ at a heating rate of 120℃ / h, and then heated to 1050℃ at a heating rate of 30℃ / h, and then held for 1h, then sprayed and quenched, the sprayed and quenched pressure is 0.4Mpa, quenched for 1h, then low-temperature tempered, the low-temperature tempering temperature is 220℃, the heating rate is 30℃ / h, and the holding time is 5h, and then naturally cooled, to obtain the forged wear-resistant steel ball for semi-autogenous grinding, wherein the sprayed and quenched medium is composed of PAG quenching liquid, PEG-400 and deionized water with a mass ratio of 5:1:100, and the sprayed and quenched medium temperature is 60℃.

[0021] Example 2 A forged wear-resistant steel ball for semi-autogenous grinding, according to mass percentage, its chemical composition includes: C: 0.8%, V+Mn: 2.7%, Cr: 2.0%, Mo: 0.35%, Ni: 0.35%, Cu: 0.25%, Nb: 0.06%, Ti: 0.04%, B: 0.005%, P: 0.015%, S: 0.01%, and the balance is Fe and inevitable impurities, wherein the mass ratio of V and Mn in the chemical composition is 7:4.

[0022] A preparation method of a forged wear-resistant steel ball for semi-autogenous grinding, comprising the following preparation steps: Step 1, low titanium pig iron, scrap steel, alloy material are added into a vacuum induction furnace for smelting, the smelting temperature is 1600℃, the contents of C, V, Mn, Cr, Mo, Ni, Cu, Nb, Ti, B, P and S are adjusted through inspection, the molten steel is obtained after deoxidation, desulfurization and slagging; Step 2, the molten steel is poured into shape, the molten steel pouring forming temperature is 1525℃, the mold is opened after the alloy melt solidifies, the steel ball embryo is taken out and air cooled to room temperature; Step 3, the steel ball embryo is heated from room temperature to 620℃ at a heating rate of 60℃ / h, and then heated to 880℃ at a heating rate of 100℃ / h, and then heated to 1075℃ at a heating rate of 20℃ / h, and then kept for 1.5h, then sprayed and quenched, the sprayed and quenched pressure is 0.6Mpa, quenched for 1.5h, then low temperature tempered, the low temperature tempering temperature is 230℃, the heating rate is 20℃ / h, and the temperature is kept for 6h, and then naturally cooled, to obtain the forged wear-resistant steel ball for semi-autogenous grinding, wherein the sprayed and quenched medium is composed of PAG quenching liquid, PEG-400 and deionized water with a mass ratio of 7:1.5:110, and the sprayed and quenched medium temperature is 70℃.

[0023] Example 3 A forged wear-resistant steel ball for semi-autogenous grinding, the chemical components of the steel ball include, by mass percentage: C: 0.85%, V+Mn: 3.2%, Cr: 2.2%, Mo: 0.45%, Ni: 0.35%, Cu: 0.4%, Nb: 0.06%, Ti: 0.06%, B: 0.008%, P: 0.010%, S: 0.010%, and the balance is Fe and inevitable impurities, wherein the mass ratio of V and Mn in the chemical components is 8:6.

[0024] A preparation method of a forged wear-resistant steel ball for semi-autogenous grinding, comprising the following preparation steps: Step 1, low titanium pig iron, scrap steel, alloy material are added into a vacuum induction furnace for smelting, the smelting temperature is 1620℃, the contents of C, V, Mn, Cr, Mo, Ni, Cu, Nb, Ti, B, P and S are adjusted through inspection, the molten steel is obtained after deoxidation, desulfurization and slagging; Step 2, the molten steel is poured into shape, the molten steel pouring forming temperature is 1550℃, the mold is opened after the alloy melt solidifies, the steel ball embryo is taken out and air cooled to room temperature; Step 3, the steel ball embryo is heated from room temperature to 650 DEG C, the heating rate is 50 DEG C / h, the temperature is kept for 30 min, then heated to 950 DEG C, the heating rate is 90 DEG C / h, the temperature is kept for 50 min, then heated to 1100 DEG C, the heating rate is 20 DEG C / h, the temperature is kept for 2 h, after forging, spray quenching is carried out, the spray quenching pressure is 0.8 Mpa, after quenching for 2 h, low-temperature tempering treatment is carried out, the low-temperature tempering treatment temperature is 240 DEG C, the heating rate is 30 DEG C / h, the temperature is kept for 7 h, after natural cooling, the semi-autogenous grinding forged wear-resistant steel ball is obtained, wherein the spray quenching medium is composed of PAG quenching liquid, PEG-400 and deionized water with a mass ratio of 8:2:120, and the spray quenching medium temperature is 80 DEG C.

[0025] Comparative Example 1 A semi-autogenous grinding forged wear-resistant steel ball, the chemical components of the steel ball include, in percentage by mass: C: 0.75%, V+Mn: 2.1%, Cr: 1.8%, Mo: 0.45%, Ni: 0.35%, Cu: 0.25%, Nb: 0.08%, Ti: 0.06%, B: 0.003%, P: 0.021%, S: 0.015%, and the balance of Fe and inevitable impurities, wherein the mass ratio of V and Mn in the chemical components is 5:3.

[0026] A preparation method of a semi-autogenous grinding forged wear-resistant steel ball, comprising the following preparation steps: Step 1, low-titanium pig iron, scrap steel and alloying materials are added into a vacuum induction furnace for smelting, the smelting temperature is 1580 DEG C, the contents of C, V, Mn, Cr, Mo, Ni, Cu, Nb, Ti, B, P and S are adjusted through inspection, after deoxidation, desulfurization and slag removal, the molten steel is obtained; Step 2, the molten steel is cast into a shape, the molten steel casting temperature is 1500 DEG C, the mold is opened after the alloy melt solidifies, and the steel ball embryo is taken out and air-cooled to room temperature; Step 3, the steel ball embryo is heated from room temperature to 580 DEG C, the heating rate is 80 DEG C / h, the temperature is kept for 20 min, then heated to 800 DEG C, the heating rate is 120 DEG C / h, the temperature is kept for 30 min, then heated to 1050 DEG C, the heating rate is 30 DEG C / h, the temperature is kept for 1 h, after forging, spray quenching is carried out, the spray quenching pressure is 0.4 Mpa, after quenching for 1 h, low-temperature tempering treatment is carried out, the low-temperature tempering treatment temperature is 220 DEG C, the heating rate is 30 DEG C / h, the temperature is kept for 5 h, after natural cooling, the semi-autogenous grinding forged wear-resistant steel ball is obtained, wherein the spray quenching medium is composed of PAG quenching liquid, PEG-400 and deionized water with a mass ratio of 5:1:100, and the spray quenching medium temperature is 60 DEG C.

[0027] Comparative Example 2 The application discloses a kind of forged wear-resistant steel balls for semi-autogenous grinding, and the chemical composition includes the following by mass percentage: C: 0.75%, V+Mn: 2.1%, Cr: 1.8%, Mo: 0.45%, Ni: 0.25%, Cu: 0.25%, Nb: 0.04%, Ti: 0.02%, B: 0.003%, P: 0.021%, S: 0.015%, and the balance is Fe and unavoidable impurities, wherein the mass ratio of V and Mn in the chemical composition is 1:10.

[0028] The application discloses a kind of forged wear-resistant steel balls for semi-autogenous grinding, and the chemical composition includes the following by mass percentage: C: 0.75%, V+Mn: 2.1%, Cr: 1.8%, Mo: 0.45%, Ni: 0.25%, Cu: 0.25%, Nb: 0.04%, Ti: 0.02%, B: 0.003%, P: 0.021%, S: 0.015%, and the balance is Fe and unavoidable impurities, wherein the mass ratio of V and Mn in the chemical composition is 1:10. Step 1, low-titanium pig iron, scrap steel and alloy materials are added into a vacuum induction furnace for smelting, the smelting temperature is 1580°C, the contents of C, V, Mn, Cr, Mo, Ni, Cu, Nb, Ti, B, P and S are adjusted through inspection, and after deoxidation, desulfurization and slag removal, molten steel is obtained; Step 2, the molten steel is poured into shape, the pouring temperature is 1500°C, the mold is opened after the alloy melt solidifies, and the steel ball blank is taken out and air-cooled to room temperature; Step 3, the steel ball blank is heated from room temperature to 580°C at a heating rate of 80°C / h, and then heated to 800°C at a heating rate of 120°C / h, and then heated to 1050°C at a heating rate of 30°C / h, and then kept for 1 h, and then sprayed and quenched, the spraying and quenching pressure is 0.4 MPa, and after quenching for 1 h, low-temperature tempering treatment is carried out, the low-temperature tempering temperature is 220°C, the heating rate is 30°C / h, and the temperature is kept for 5 h, and then naturally cooled, to obtain the forged wear-resistant steel ball for semi-autogenous grinding, wherein the spraying and quenching medium is composed of PAG quenching liquid, PEG-400 and deionized water in a mass ratio of 5:1:100, and the spraying and quenching medium temperature is 60°C.

[0029] Comparative example 3 The application discloses a kind of forged wear-resistant steel balls for semi-autogenous grinding, and the chemical composition includes the following by mass percentage: C: 0.75%, V+Mn: 2.1%, Cr: 1.8%, Mo: 0.45%, Ni: 0.25%, Cu: 0.25%, Nb: 0.04%, Ti: 0.02%, B: 0.003%, P: 0.021%, S: 0.015%, and the balance is Fe and unavoidable impurities, wherein the mass ratio of V and Mn in the chemical composition is 1:10.

[0030] The application discloses a kind of forged wear-resistant steel balls for semi-autogenous grinding, and the chemical composition includes the following by mass percentage: C: 0.75%, V+Mn: 2.1%, Cr: 1.8%, Mo: 0.45%, Ni: 0.25%, Cu: 0.25%, Nb: 0.04%, Ti: 0.02%, B: 0.003%, P: 0.021%, S: 0.015%, and the balance is Fe and unavoidable impurities, wherein the mass ratio of V and Mn in the chemical composition is 1:10. Step 1, low titanium pig iron, scrap steel, alloy material are added into a vacuum induction furnace for smelting, the smelting temperature is 1580℃, the contents of C, V, Mn, Cr, Mo, Ni, Cu, Nb, Ti, B, P and S are adjusted by inspection, after deoxidation, desulfurization and slagging, molten steel is obtained; Step 2, the molten steel is poured into shape, the molten steel pouring forming temperature is 1500℃, after the alloy melt solidifies, the mold is opened, the steel ball embryo is taken out and air cooled to room temperature, and a steel ball embryo is obtained; Step 3, the steel ball embryo is heated from room temperature to 580℃ at a heating rate of 100℃ / h, then heated to 800℃ at a heating rate of 150℃ / h, and then heated to 1050℃ at a heating rate of 50℃ / h, and then kept for 1h, then sprayed and quenched, the sprayed and quenched pressure is 0.4Mpa, after quenching for 1h, low temperature tempering treatment is carried out, the low temperature tempering treatment temperature is 220℃, the heating rate is 30℃ / h, and the temperature is kept for 5h, and then naturally cooled, and a forged wear-resistant steel ball for semi-autogenous grinding is obtained, wherein the sprayed and quenched medium is composed of PAG quenching liquid, PEG-400 and deionized water with a mass ratio of 5:1:100, and the sprayed and quenched medium temperature is 60℃.

[0031] Comparative example 4 A forged wear-resistant steel ball for semi-autogenous grinding, according to mass percentage, the chemical components include: C: 0.75%, V+Mn: 2.1%, Cr: 1.8%, Mo: 0.45%, Ni: 0.25%, Cu: 0.25%, Nb: 0.04%, Ti: 0.02%, B: 0.003%, P: 0.021%, S: 0.015%, and the balance is Fe and inevitable impurities, wherein the mass ratio of V and Mn in the chemical components is 5:3.

[0032] A preparation method of a forged wear-resistant steel ball for semi-autogenous grinding, comprising the following preparation steps: Step 1, low titanium pig iron, scrap steel, alloy material are added into a vacuum induction furnace for smelting, the smelting temperature is 1580℃, the contents of C, V, Mn, Cr, Mo, Ni, Cu, Nb, Ti, B, P and S are adjusted by inspection, after deoxidation, desulfurization and slagging, molten steel is obtained; Step 2, the molten steel is poured into shape, the molten steel pouring forming temperature is 1500℃, after the alloy melt solidifies, the mold is opened, the steel ball embryo is taken out and air cooled to room temperature, and a steel ball embryo is obtained; Step 3, the steel ball embryo is heated from room temperature to 580℃ at a heating rate of 80℃ / h, and is kept for 20 min, then is continuously heated to 800℃ at a heating rate of 120℃ / h, and is kept for 30 min, then is continuously heated to 1050℃ at a heating rate of 30℃ / h, and is kept for 1h, and is forged and then is sprayed and quenched, the sprayed and quenched pressure is 0.4Mpa, after quenching for 1h, low-temperature tempering treatment is carried out, the low-temperature tempering treatment temperature is 220℃, the heating rate is 30℃ / h, and the keeping time is 5h, and after natural cooling, the forged wear-resistant steel ball for semi-autogenous grinding is obtained, wherein the sprayed and quenched medium is composed of PAG quenching liquid and deionized water with a mass ratio of 6:100, and the sprayed and quenched medium temperature is 60℃.

[0033] Comparative Example 5 A forged wear-resistant steel ball for semi-autogenous grinding, according to mass percentage, its chemical components include: C: 0.75%, V+Mn: 2.1%, Cr: 1.8%, Mo: 0.45%, Ni: 0.25%, Cu: 0.25%, Nb: 0.04%, Ti: 0.02%, B: 0.003%, P: 0.021%, S: 0.015%, and the rest is Fe and inevitable impurities, wherein the mass ratio of V and Mn in the chemical components is 5:3.

[0034] A preparation method of a forged wear-resistant steel ball for semi-autogenous grinding, comprising the following preparation steps: Step 1, low-titanium pig iron, scrap steel and alloy materials are added into a vacuum induction furnace for smelting, the smelting temperature is 1580℃, the contents of C, V, Mn, Cr, Mo, Ni, Cu, Nb, Ti, B, P and S are adjusted through inspection, and after deoxidation, desulfurization and slag removal, the molten steel is obtained; Step 2, the molten steel is cast into a shape, the molten steel casting temperature is 1500℃, the mold is opened after the alloy melt is solidified, and the steel ball embryo is taken out and air-cooled to room temperature; Step 3, the steel ball embryo is heated from room temperature to 580℃ at a heating rate of 80℃ / h, and is kept for 20 min, then is continuously heated to 800℃ at a heating rate of 120℃ / h, and is kept for 30 min, then is continuously heated to 1050℃ at a heating rate of 30℃ / h, and is kept for 1h, and is forged and then is sprayed and quenched, the sprayed and quenched pressure is 0.4Mpa, after quenching for 1h, low-temperature tempering treatment is carried out, the low-temperature tempering treatment temperature is 220℃, the heating rate is 30℃ / h, and the keeping time is 5h, and after natural cooling, the forged wear-resistant steel ball for semi-autogenous grinding is obtained, wherein the sprayed and quenched medium is composed of PAG quenching liquid, PEG-400 and deionized water with a mass ratio of 5:1:100, and the sprayed and quenched medium temperature is 30℃.

[0035] Comparative Example 6 The application discloses a kind of semi-autogenous grinding with forged wear-resistant steel ball, and its chemical composition includes the following by mass percentage: C: 0.75%, V+Mn: 2.1%, Cr: 1.8%, Mo: 0.45%, Ni: 0.25%, Cu: 0.25%, Nb: 0.04%, Ti: 0.02%, B: 0.003%, P: 0.021%, S: 0.015%, and the balance is Fe and unavoidable impurities, wherein the mass ratio of V and Mn in the chemical composition is 5:3.

[0036] A kind of semi-autogenous grinding with forged wear-resistant steel ball preparation method, including the following preparation steps: Step 1, low titanium pig iron, scrap, alloy material are added to vacuum induction furnace for smelting, and the smelting temperature is 1580 DEG C, and the content of C, V, Mn, Cr, Mo, Ni, Cu, Nb, Ti, B, P, S is adjusted after inspection, after deoxidation, desulphurization, slagging, the molten steel is obtained; Step 2, the molten steel is cast into shape, and the molten steel casting temperature is 1500 DEG C, and the mold is opened after the alloy melt solidifies, and the steel ball embryo is taken out and air cooled to room temperature; Step 3, the steel ball embryo is heated from room temperature to 580 DEG C, the heating rate is 80 DEG C / h, and the temperature is kept for 20 min, then heated to 800 DEG C, the heating rate is 120 DEG C / h, and the temperature is kept for 30 min, then heated to 1050 DEG C, the heating rate is 30 DEG C / h, and the temperature is kept for 1 h, then sprayed and quenched after forging, the sprayed quenching pressure is 0.4 Mpa, and quenched for 1 h, then low-temperature tempering treatment is carried out, the low-temperature tempering treatment temperature is 220 DEG C, the heating rate is 50 DEG C / h, and the temperature is kept for 5 h, and then naturally cooled, to obtain the semi-autogenous grinding with forged wear-resistant steel ball, wherein the sprayed quenching medium is composed of PAG quenching liquid, PEG-400 and deionized water with a mass ratio of 5:1:100, and the sprayed quenching medium temperature is 60 DEG C.

[0037] Performance test The performance parameters of the semi-autogenous grinding with forged wear-resistant steel balls prepared in examples 1-3 and comparative examples 1-6 of the application are as follows: Hardness: tested according to the national standard GB / T 230.1-2018 "Metallic materials-Lohr hardness test-Part 1: Test method"; Impact energy: tested according to the national standard GB / T 229-2020 "Metallic materials-Charpy pendulum impact test method"; The test results are shown in Table 1.

[0038] Table 1 Performance parameters of semi-autogenous grinding with forged wear-resistant steel balls prepared in examples 1-3 and comparative examples 1-6

[0039] As shown in Table 1, the forged wear-resistant steel ball prepared by the application has high surface and core hardness, high impact energy, can significantly improve wear resistance, reduce surface wear and fragmentation, has strong impact resistance, is not broken by large ore impact, has good hardness uniformity, maintains stable grinding efficiency, reduces ball replacement frequency and downtime, prolongs service life, comprehensively improves mill operation rate, reduces steel consumption and energy consumption per ton of ore, and has outstanding economic efficiency.

[0040] The embodiments are only an explanation of the application, and are not a limitation of the application, and those skilled in the art can make modifications to the embodiments without creative contribution according to the needs after reading the specification, but as long as the modifications are within the scope of the claims of the application, they are protected by the Patent Law.

Claims

1. A forged wear-resistant steel ball for semi-autogenous grinding, characterized in that: Calculated by mass percentage, its chemical composition includes: C: 0.75-0.85%, V+Mn: 2.1-3.2%, Cr: 1.8-2.2%, Mo: 0.25-0.45%, Ni: 0.15-0.35%, Cu: 0.25-0.4%, Nb: 0.04-0.08%, Ti: 0.01-0.06%, B: 0.003-0.008%, P≤0.021%, S≤0.020%, and the balance is Fe and unavoidable impurities.

2. The forged wear-resistant steel ball for semi-autogenous grinding according to claim 1, characterized in that: The chemical composition also satisfies the quantitative relationship: [C] / ([Nb] + [Ti])≥6.2, [Cr] + [Mo]≥2.2%; [Ni] + [Cu]≥0.5%; wherein [C], [Nb], [Ti], [Cr], [Mo], [Ni], and [Cu] are the mass percentage contents of C, Nb, Ti, Cr, Mo, Ni, and Cu, respectively.

3. The forged wear-resistant steel ball for semi-autogenous grinding according to claim 1, characterized in that: The mass ratio of V to Mn in the chemical composition is 5-8:3-6.

4. A method for preparing a forged wear-resistant steel ball for semi-autogenous grinding according to any one of claims 1 to 3, characterized in that: The method comprises the following preparation steps: Step 1: low-titanium pig iron, scrap steel, and alloy material are added into a vacuum induction furnace for smelting, and the contents of C, V, Mn, Cr, Mo, Ni, Cu, Nb, Ti, B, P, and S are adjusted after inspection. Molten steel is obtained after deoxidation, desulfurization, and slag removal. Step 2: pour the molten steel into the mold, open the mold after the alloy melt solidifies, take it out and air-cool it to room temperature to obtain a steel ball embryo; Step 3: Forge the steel ball blank using three-stage heating, spray quench after forging, quench for 1-2 hours, and then perform low-temperature tempering treatment. After natural cooling, the forged wear-resistant steel ball for semi-autogenous grinding is obtained.

5. The method for preparing a forged wear-resistant steel ball for semi-autogenous grinding according to claim 4, characterized in that: The smelting temperature in step 1 is 1580-1620°C.

6. The method for preparing a forged wear-resistant steel ball for semi-autogenous grinding according to claim 4, characterized in that: The temperature of the molten steel pouring molding in step 2 is 1500-1550°C.

7. The method for preparing a forged wear-resistant steel ball for semi-autogenous grinding according to claim 4, characterized in that: The three-stage heating forging process in step 3 is specifically as follows: heating from room temperature to 580-650°C, heating rate ≤80°C / h, keeping warm for 20-30 minutes, continuing heating to 800-950°C, heating rate ≤120°C / h, keeping warm for 30-50 minutes, continuing heating to 1050-1100°C, heating rate ≤30°C / h, keeping warm for 1-2 hours.

8. The method for preparing a forged wear-resistant steel ball for semi-autogenous grinding according to claim 4, characterized in that: In step 3, the spray quenching medium consists of PAG quenching liquid, PEG-400 and deionized water in a mass ratio of 5-8:1-2:100-120; the temperature of the spray quenching medium is 60-80°C.

9. The method for preparing a forged wear-resistant steel ball for semi-autogenous grinding according to claim 4, characterized in that: The spray quenching pressure in step 3 is 0.4-0.8 MPa.

10. The method for preparing forged wear-resistant steel balls for semi-autogenous grinding according to claim 4, characterized in that: In step 3, the low-temperature tempering treatment temperature is 220-240° C., the heating rate is ≤30° C. / h, and the heat preservation time is 5-7 hours.

Images