High-toughness wear-resistant lining plate material suitable for rod mill and preparation method of high-toughness wear-resistant lining plate material

Abstract

The invention discloses a high-toughness wear-resistant lining plate material suitable for a rod mill and a preparation method of the high-toughness wear-resistant lining plate material, and belongs to the technical field of metal materials. The lining plate meeting the use requirements of the rod mill can be produced after the steps of steelmaking by a medium-frequency induction furnace, casting and molding by sodium silicate sand, heating and annealing at 950 DEG C, quenching and cooling by heating air at 890 DEG C, and heating and tempering at 600 DEG C. The high-toughness wear-resistant lining plate material prepared through the preparation method is low in cost and good in formability and has high toughness, hardenability and hardenability, meanwhile, rare earth elements are adopted for purification, modification and alloying treatment, and the long service life of the lining plate is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal materials, in particular to a high-strength, tough, and wear-resistant lining material suitable for a rod mill and a preparation method thereof. Background Art

[0002] Rod mills are widely used in industries such as artificial sand making, mine material selection, chemical grinding, electric coal grinding, and building materials. Although they have disadvantages such as low efficiency, high noise, and high steel consumption, they remain the preferred choice in the raw material crushing industry chain, especially in mineral processing operations, where they are irreplaceable. The working principle of a rod mill for mining is to use a high-voltage, high-power motor driven by a rigid coupling (air clutch, hydraulic coupling) connected to a gear pair, thereby driving the rotation of the cylinder. A liner is laid on the inner wall of the cylinder to protect it, and the interior of the cylinder is filled with steel rods of a certain size to serve as the grinding medium. As the cylinder rotates, the minerals and grinding rods inside are effectively lifted and thrown off, achieving the effect of grinding the minerals.

[0003] In rod mill grinding lines, the loss rate of liners and grinding steel rods accounts for a significant portion of total beneficiation costs, while loading and unloading liners and rods accounts for approximately 60% of the man-hours required for routine mill maintenance. Currently, rod mill liners are mostly made of high-manganese steel. The goal is to extend the service life of high-manganese steel by leveraging its high surface strength and high core toughness under high-energy impact loads. However, due to the limited operating environment, the impact energy experienced by rod mill liners during operation is low, preventing the steel from fully utilizing its plastic deformation strengthening properties. This results in poor wear resistance and severe liner deformation, resulting in bolt shortening, liner breakage, or shattering. This shortens maintenance cycles and makes liner removal difficult. Consequently, a set of high-manganese steel liners in a rod mill has a service life of only four to five months, increasing factory production costs and worker workload.

[0004] Therefore, in order to improve the service life of rod mill linings and liberate productivity, it is necessary to research and develop rod mill lining materials and preparation processes, and strive to produce rod mill linings with important academic significance and economic value to fill the gaps in the industry. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-strength, tough, wear-resistant lining material suitable for a rod mill and a preparation method thereof, which has low cost, good formability, high toughness, hardenability and hardenability, and is purified, modified and alloyed with rare earth elements to achieve a long service life of the lining.

[0006] To achieve the above object, the present invention provides a high-strength, tough and wear-resistant lining plate material suitable for rod mills, comprising the following components by mass percentage: 0.50 - 0.60 wt% C, 0.60 - 0.80 wt% Si, 1.20 - 1.40 wt% Mn, 0 - 0.035 wt% P, 0 - 0.035 wt% S, 2.00 - 2.50 wt% Cr, 0.30 - 0.50 wt% Ni, 0.20 - 0.40 wt% Mo, 0.15 wt% Re, and the balance is iron.

[0007] Preferably, the structure of the high-strength, tough and wear-resistant lining plate material is a mixture of tempered sorbite, bainite and carbide structure.

[0008] Preferably, the hardness of the high-strength, tough and wear-resistant lining plate material is ≥ 44.0 HRC.

[0009] Preferably, the impact toughness of the high-strength, tough and wear-resistant lining plate material is ≥ 90.0 J / cm 2 .

[0010] Preferably, the tensile strength of the high-strength, tough and wear-resistant lining plate material is ≥ 1300 Mpa, and the yield strength is ≥ 1100 Mpa.

[0011] The present invention also provides a preparation method of the above high-strength, tough and wear-resistant lining plate material suitable for rod mills, comprising the following steps:

[0012] (1) Put the raw materials of the additive elements and scrap steel into the medium-frequency induction furnace as the steelmaking raw materials, and carry out final deoxidation with aluminum in the furnace before tapping.

[0013] (2) After the molten steel is tapped into the tundish, add 0.5 Kg of slag aggregator and start to calm down. After calming down, carry out slag removal. The whole process of calming + adding slag aggregator + slag removal is more than 3 minutes. After slag removal 2 - 3 times, pour and form into a lining plate. Then, the lining plate is slowly cooled for 24 hours and then air-cooled in the open box. After air-cooling, use the cold cutting method to remove the riser and gate of the lining plate and clean sand and polish.

[0014] (3) The polished lining plate is subjected to a heat treatment process to form a high-strength and tough lining plate. The heat treatment process includes annealing with heating and holding at 950 °C for 6 hours, air quenching with heating and holding at 890 °C for 6 hours, and tempering with heating and holding at 600 °C for 6 hours.

[0015] Preferably, in step (1), the raw materials of the additive elements are high-carbon ferromanganese alloy, ferrosilicon alloy, high-carbon ferrochrome alloy, ferromolybdenum alloy, nickel plate, ferrovanadium alloy, 1# rare earth alloy (Si-Mg-Re alloy, rare earth content is 30%), aluminum wire and carburizer.

[0016] Preferably, in step (1), aluminum is used for final deoxidation in the furnace before tapping the molten steel, and the tapping temperature is 1600 - 1620°C; the No. 1 rare earth alloy is added into the ladle. The adding method is to place the No. 1 rare earth alloy at the bottom of the ladle, and cover the alloy with a steel plate with a thickness of 0.2 mm.

[0017] Preferably, in step (2), the molding process design for casting is the wood mold + resin-hardened sodium silicate sand molding process. Among them, the weight ratio of raw materials in the resin-hardened sodium silicate quartz sand is quartz sand: sodium silicate: organic resin = 100:4:1; during the pouring process of the molten steel, slag blocking treatment is carried out with slag blocking cotton. The pouring temperature is 1520 - 1550°C, and the pouring time for a single lining plate is less than 1 minute.

[0018] Therefore, the present invention adopts the above-mentioned high-strength, tough and wear-resistant lining plate material for rod mills and its preparation method, and has the following beneficial effects:

[0019] (1) The structure of the lining plate material prepared by the present invention is tempered sorbite + bainite + carbide. The average hardness value is 44.78 HRC, the average impact toughness is 99.66 (J / cm 2 ), the average tensile strength is 1376 Mpa, the average yield strength is 1186 Mpa, with strong impact resistance and wear resistance to abrasive particle wear;

[0020] (2) The lining plate material prepared by the present invention has low cost, good formability, high toughness, hardenability and hardening property. At the same time, rare earth elements are used for purification, modification and alloying treatment to achieve the long life of the lining plate. The produced alloy steel lining plate can meet the use requirements of the rod mill, and the service life is 2.2 - 2.75 times that of high manganese steel; it greatly reduces the number of equipment shutdowns for maintenance and reduces the comprehensive production cost.

[0021] The technical solution of the present invention will be further described in detail below through the drawings and embodiments. Brief Description of the Drawings

[0022] Figure 1 is a photo of the working surface of the lining plate of the high-strength, tough and wear-resistant lining plate material for rod mills prepared in Example 1 of the present invention;

[0023] Figure 2 is a photo of the side of the lining plate of the high-strength, tough and wear-resistant lining plate material for rod mills prepared in Example 1 of the present invention;

[0024] Figure 3 is the annealing process curve during the preparation of the high-strength, tough and wear-resistant lining plate material in Example 1 of the present invention;

[0025] Figure 4 is the quenching process curve during the preparation of the high-strength, tough and wear-resistant lining plate material in Example 1 of the present invention;

[0026] Figure 5 It is the tempering process curve in the preparation process of the high-strength, tough and wear-resistant lining plate material in the first embodiment of the present invention;

[0027] Figure 6 It is the metallographic structure diagram of the high-strength, tough and wear-resistant lining plate material in the first embodiment of the present invention. Specific Embodiments

[0028] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments.

[0029] Unless otherwise defined, the technical terms or scientific terms used in the present invention should have the ordinary meaning understood by those of ordinary skill in the field to which the present invention belongs.

[0030] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the accompanying drawings in the embodiments of the present invention will be combined below Figures 1 to 6 The technical solutions of the present invention will be described clearly and completely. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0031] The present invention provides a high-strength, tough and wear-resistant lining plate material applicable to a rod mill, which comprises the following components in mass percentage: 0.50 - 0.60wt% C, 0.60 - 0.80wt% Si, 1.20 - 1.40wt% Mn, 0 - 0.035wt% P, 0 - 0.035wt% S, 2.00 - 2.50wt% Cr, 0.30 - 0.50wt% Ni, 0.20 - 0.40wt% Mo, 0.15wt% Re, and the balance is iron.

[0032] The structure of the high-strength, tough and wear-resistant lining plate material is a mixture of tempered sorbite, bainite and carbide structure. The hardness of the high-strength, tough and wear-resistant lining plate material is ≥ 44.0HRC. The impact toughness of the high-strength, tough and wear-resistant lining plate material is ≥ 90.0J / cm 2 . The tensile strength of the high-strength, tough and wear-resistant lining plate material is ≥ 1300Mpa, and the yield strength is ≥ 1100Mpa.

[0033] Example 1

[0034] This example provides a high-strength, tough and wear-resistant lining plate material applicable to a rod mill, and its preparation method includes the following steps:

[0035] (1) The high-strength, tough and wear-resistant material lining plate is smelted in a 1000 Kg intermediate frequency induction furnace. The raw materials for steelmaking are 930 Kg of scrap steel, 8 Kg of high-carbon ferromanganese alloy, 5 Kg of ferrosilicon alloy, 45 Kg of high-carbon ferrochromium alloy, 7 Kg of ferromolybdenum alloy, 5 Kg of nickel plate, 5 Kg of No. 1 rare earth alloy, 1 Kg of aluminum wire and 1 Kg of recarburizer. Final deoxidation with aluminum is carried out in the furnace before tapping, and the tapping temperature is 1600 - 1620 °C. The No. 1 rare earth alloy is added into the ladle. The adding method is to place the No. 1 rare earth alloy at the bottom of the ladle and cover it with a steel plate 0.2 mm thick above the alloy.

[0036] (2) After the molten steel flows into the tundish, 0.5 Kg of slag aggregating agent is added and then the steel starts to be statically cast. After static casting, slag skimming is carried out. The whole process of static casting + slag aggregation + slag skimming should be more than 3 minutes, and slag skimming is carried out 2 - 3 times before starting pouring. The molding process design is a wooden mold + ester-hardened sodium silicate sand molding process. The ratio of ester-hardened sodium silicate quartz sand is quartz sand : sodium silicate : organic ester configured by weight percentage as 100:4:1. During the pouring process of the molten steel, slag blocking treatment is carried out with slag blocking cotton. The pouring temperature is 1520 - 1550 °C, and the pouring time for a single lining plate is less than 1 minute. After the lining plate is poured, it is slowly cooled for 24 hours. After the slow cooling ends, it is taken out of the box and air-cooled. After air-cooling, the riser and gating of the lining plate are removed by cold cutting method, and then it is sandblasted and polished. The produced lining plate is shown in Figure 1 and Figure 2 , and the actual chemical composition is shown in Table 1, with the rest being iron.

[0037] Table 1 Actual Chemical Composition of High-Strength, Tough and Wear-Resistant Lining Plate Material

[0038]

[0039] (3) The polished lining plate is subjected to a heat treatment process to form a high-strength and tough lining plate. The heat treatment process includes annealing with heating and holding at 950 °C for 6 hours, air quenching with heating and holding at 890 °C for 6 hours, and tempering with heating and holding at 600 °C for 6 hours. The annealing process curve, quenching process curve and tempering process curve are shown in Figure 3 , Figure 4 and Figure 5 .

[0040] The lining plate prepared in Example 1 is subjected to microstructure detection and mechanical property detection, and the results are as follows:

[0041] (I) Metallographic Microstructure Detection

[0042] The heat-treated liner plate was cut by a wire cutting machine. The size of the cut specimen was 20×20×15 mm. The metallographic specimen was prepared by the process of grinding flat with a belt grinding machine, grinding with 240#, 320#, 600#, and 800# sandpapers, and then polishing with flannel. The prepared metallographic specimen was corroded with a 4% volume percentage nitric acid alcohol solution, and a metallographic microscope with the model 4XC-TV was used to observe the metallographic structure. The results are shown in Figure 6 .

[0043] It can be seen from the metallographic structure photos of the specimen that after the liner plate was treated by annealing at 950°C + air quenching at 890°C + air cooling tempering at 600°C, its internal structure was tempered sorbite + bainite + carbide, meeting the requirements of the process design for the structure. This tempered sorbite + bainite + carbide structure can greatly improve the strength of the material and improve the toughness, and can achieve a reasonable match of strength and toughness.

[0044] (2) Hardness test

[0045] The heat-treated liner plate was longitudinally cut symmetrically along the narrow side by a wire cutting machine. Hardness test specimens were taken from the surface to half of the thickness. The specimens were ground flat with a belt grinding machine, and the hardness values of the cross-section of the specimens were measured with a material hardness tester with the model R(D)-150A1. The measurement points started from 3 mm from the surface and ended at 53 mm, with a total of 5 measurement points. The distance between the measurement points was 10 mm. The results are shown in Table 2.

[0046] Table 2 Rockwell hardness of the high-strength and tough wear-resistant liner plate material

[0047]

[0048] From the analysis of the hardness results of the high-strength and tough liner plate in Table 2, it can be obtained that after heat treatment, the cross-sectional hardness of this high-strength and tough wear-resistant liner plate material is relatively uniform, and the change range is only 44.5 - 45.0 HRC, with an average value of 44.78 HRC. This shows that after the heat treatment process, the internal and external hardness fluctuation range of this high-strength and tough wear-resistant liner plate material is small, and the wear resistance is stable during use, and there will be no phenomenon of local rapid wear. Compared with the highest value of 20 HRC of the high manganese steel liner plate, this value increases by 24.78 HRC, an increase of 123.9%.

[0049] (3) Impact performance of the high-strength and tough wear-resistant liner plate material

[0050] At the center of the cross-section of the heat-treated liner plate, 3 impact blank specimens with the size of 12×12×55 mm were cut out by a wire cutting machine, and then ground into standard non-notch impact specimens with the size of 10×10×55 mm. A Charpy impact test was carried out on the specimens with a material impact tester with the model N1500C. The test results are shown in Table 3.

[0051] Table 3 Impact Properties of High Strength, Toughness and Wear-Resistant Liner Materials

[0052]

[0053] As shown in the results of Table 3, after the high strength, toughness and wear-resistant liner materials are treated by the heat treatment process, the notch-free impact toughness of the specimens is greater than 90 J / cm 2 , and the fluctuation range is 90.62 - 114.64 J / cm 2 , and its average impact toughness is 99.66 J / cm 2 . Compared with the average impact toughness of 196 J / cm of the high manganese steel liner 2 , although this value is reduced by 96.38 J / cm 2 , such an impact toughness value can fully meet the use requirements of the rod mill, indicating that the rod mill liner prepared with this material and heat treatment process will not break during use, enabling the equipment to operate stably.

[0054] (IV) Tensile Properties of High Strength, Toughness and Wear-Resistant Liners

[0055] Tensile test specimens are taken from 1 / 4 of the thickness of the liner treated by the heat treatment process. After being processed into standard Φ10 mm standard tensile specimens by a lathe and an external cylindrical grinder, a tensile test is carried out using an electronic universal material testing machine with models 5989 and 600 KN. In the experiment, 2 specimens are taken in each group to test the mechanical properties of the experimental steel, including: tensile strength (Rm), non-proportional extension strength (Rp0.2), elongation after fracture (A), and reduction of area (Z). The test results are shown in Table 4.

[0056] Table 4 Tensile Properties of High Strength, Toughness and Wear-Resistant Liner Materials

[0057] Specimen number Rm (Mpa) Rp0.2 (Mpa) A(％) Z(％) 1 1376 1183 8.10 8 2 1376 1189 7.0 7 Average value 1376 1186 7.55 7.5

[0058] As can be seen from the results of Table 4, after the high strength, toughness and wear-resistant liner materials are treated by the heat treatment process, the average tensile strength reaches 1376 Mpa, the average yield strength reaches 1186 Mpa, and the elongation and reduction of area are both greater than 7%. It shows that the designed high strength, toughness and wear-resistant liner materials for the rod mill have high strength and certain plasticity after being treated by the heat treatment process, especially the yield strength. The yield strength of this high strength, toughness and wear-resistant liner is increased by 715 - 843 Mpa compared with that of the high manganese steel liner. As is well known, when the wear-resistant material liner is working, it will first undergo plastic deformation under the action of abrasive particles. When the plastic deformation reaches a certain degree, grinding phenomenon begins to occur. The main index affecting plastic deformation is the yield strength of the liner material. Therefore, increasing the yield strength of the liner material can avoid or delay the generation time of grinding, reduce the wear amount of the liner, increase the service life of the liner, and enable the equipment to operate stably.

[0059] (V) Service effect of high-strength, tough and wear-resistant lining plates

[0060] In February 2024, a batch of high-strength, tough and wear-resistant lining plates were made by using medium-frequency induction furnace steelmaking and water glass sand molding process according to the chemical composition range designed in Table 1. After the lining plates were treated by Figures 3 - 5 the heat treatment process, they were installed in a Φ3.2x4.5m rod mill equipment of a certain company in March (the steel rod size is Φ75-100mmx3m) and started to be used. In February 2025, the lining plates were taken off the line because the working surface of the lining plates was worn from the original thickness of 110mm to 35mm. During the use process of the high-strength, tough and wear-resistant lining plates, no phenomena such as deformation, breakage and fracture of the lining plates occurred. Excluding the shutdown and maintenance time caused by other reasons during the production process, the actual use time of the high-strength, tough and wear-resistant lining plates was 11 months. Compared with the use time of the original high manganese steel lining plates, the use time was extended by 6-7 months, and the service life was 2.2-2.75 times that of the high manganese steel. The number of equipment shutdown and maintenance times was greatly reduced, and the comprehensive production cost was lowered.

[0061] Therefore, the high-strength, tough and wear-resistant lining plate material for rod mill and its preparation method of the present invention have low cost and good formability, and have high toughness, hardenability and hardenability. At the same time, rare earth elements are used for purification, modification and alloying treatment to achieve the long life of the lining plates.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that they can still modify or equivalently replace the technical solutions of the present invention, and these modifications or equivalent replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A high-strength, tough and wear-resistant lining plate material applicable to rod mills, characterized in that, The components by mass percentage are as follows: 0.50 - 0.60 wt% C, 0.60 - 0.80 wt% Si, 1.20 - 1.40 wt% Mn, 0 - 0.035 wt% P, 0 - 0.035 wt% S, 2.00 - 2.50 wt% Cr, 0.30 - 0.50 wt% Ni, 0.20 - 0.40 wt% Mo, 0.15 wt% Re, and the balance is iron.

2. A high-strength, tough and wear-resistant lining plate material applicable to a rod mill according to claim 1, characterized in that, The structure of the high-strength, tough and wear-resistant lining plate material is a mixture of tempered sorbite, bainite and carbide structure.

3. A high-strength, tough and wear-resistant lining plate material suitable for a rod mill according to claim 1, characterized in that, The hardness of the high-strength, tough and wear-resistant lining plate material is ≥ 44.0 HRC.

4. A high-strength, tough and wear-resistant lining plate material applicable to a rod mill according to claim 1, characterized in that, The impact toughness of the high-strength, tough and wear-resistant lining plate material is ≧ 90 J / cm 2 .

5. The high-strength, tough and wear-resistant lining plate material applicable to a rod mill according to claim 1, wherein The tensile strength of the high-strength, tough and wear-resistant lining plate material is ≥ 1300 Mpa, and the yield strength is ≥ 1100 Mpa.

6. A preparation method of a high-strength, tough and wear-resistant lining plate material applicable to a rod mill as described in any one of claims 1-5, characterized in that, It includes the following steps: (1) Put the raw materials of additive elements and scrap steel as the steelmaking raw materials into an intermediate frequency induction furnace to smelt into molten steel, and conduct final deoxidation with aluminum in the furnace before tapping. (2) After the molten steel is tapped into the tundish, add 0.5 Kg of slag collecting agent and start to calm. After calming, slag removal is carried out. The whole process of calming + slag collecting + slag removal is more than 3 minutes. After slag removal 2 - 3 times, it is cast into a lining plate. Subsequently, the lining plate is slowly cooled for 24 hours and then air-cooled after unpacking. After air-cooling, the riser and gate of the lining plate are removed by cold cutting method, and then sand cleaning and grinding are carried out. (3) The ground lining plate is subjected to a heat treatment process to form a high-strength and tough lining plate. The heat treatment process includes annealing with heating and holding at 950 °C for 6 hours, air quenching with heating and holding at 890 °C for 6 hours, and tempering with heating and holding at 600 °C for 6 hours.

7. The preparation method of a high-strength, tough and wear-resistant lining plate material applicable to a rod mill according to claim 6, characterized in that, In step (1), the raw materials of additive elements are high-carbon ferromanganese alloy, ferrosilicon alloy, high-carbon ferrochromium alloy, ferromolybdenum alloy, nickel plate, No. 1 rare earth alloy, aluminum wire and carburizer. The No. 1 rare earth alloy is a Si-Mg-Re alloy with a rare earth content of 30%.

8. The preparation method of a high-strength, tough and wear-resistant lining plate material applicable to a rod mill according to claim 7, characterized in that, In step (1), final deoxidation with aluminum is carried out in the furnace before tapping the molten steel, and the tapping temperature is 1600 - 1620 °C; the No. 1 rare earth alloy is added into the ladle. The adding method is to put the No. 1 rare earth alloy at the bottom of the ladle, and cover the No. 1 rare earth alloy with a steel plate with a thickness of 0.2 mm.

9. The preparation method of a high-strength, tough and wear-resistant lining plate material applicable to a rod mill according to claim 6, characterized in that, In step (2), the molding process design for casting is a wooden mold + resin-hardened sodium silicate quartz sand molding process. Among them, the weight ratio of the raw materials in the resin-hardened sodium silicate quartz sand is quartz sand: sodium silicate: organic resin = 100:4:1; during the pouring process of molten steel, slag blocking treatment is carried out with slag blocking cotton. The pouring temperature is 1520 - 1550 °C, and the pouring time for a single lining plate is less than 1 minute.

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