A high-toughness wear-resistant lining plate material suitable for a rod mill and a preparation method thereof

Abstract

The application discloses a high-toughness wear-resistant lining plate material suitable for a rod mill and a preparation method thereof, and belongs to the technical field of metal materials. The lining plate material meeting the use requirements of the rod mill is produced after the following treatments: medium-frequency induction furnace steel smelting, water glass sand casting forming, 950 DEG C heating annealing, 890 DEG C heating air quenching and cooling, and 600 DEG C heating tempering treatment. The high-toughness wear-resistant lining plate material prepared by the above preparation method has the advantages of low cost, good formability, high toughness, hardenability and quenching hardenability, and the rare earth elements are used for purifying, modifying and alloying treatment of the lining plate, so that the long service life of the lining plate is realized.

Description

TECHNICAL FIELD

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

[0002] The rod mill is widely used in artificial sand making, mine material selection, chemical powder grinding, power coal grinding and building material industries. Although it has the disadvantages of low equipment efficiency, high noise and high steel consumption in use, it is still the first choice in the raw material crushing industry chain, especially in the mineral processing operation, and it is an irreplaceable equipment. The working principle of the rod mill for mine is that a high-voltage and high-power motor is driven to rotate the cylinder through a rigid coupling (air clutch, hydraulic coupling) connected to a gear pair, thereby driving the cylinder to rotate. The lining plate is laid on the inner wall of the cylinder to protect the cylinder, and the cylinder is filled with steel rods of a certain size as grinding media. With the rotation of the cylinder, the internal mineral and grinding rods are effectively lifted and thrown, achieving the grinding effect of the mineral.

[0003] In the process line of the rod mill, the wear rate of the lining plate and the grinding steel rod accounts for a large part of the total mineral processing cost, and the installation and removal of the lining plate and the steel rod accounts for about 60% of the manual working hours in the daily maintenance of the mill. At present, most of the lining plates of the rod mill are still made of high manganese steel. It is assumed that the reasonable matching of the high surface strength and high toughness of the core of high manganese steel under high energy impact load can improve the service life of high manganese steel. However, for the rod mill equipment, due to the limited working environment, the impact energy on the lining plate is low, and the characteristics of plastic deformation strengthening of high manganese steel cannot be fully utilized. In addition to poor wear resistance, there are also problems such as serious deformation of the lining plate, shortening of the fastening bolts, and breaking or crushing of the lining plate, resulting in short maintenance period, difficult disassembly of the lining plate, and other phenomena. The service life of a set of high manganese steel lining plate in the rod mill is only 4-5 months, which increases the production cost of the factory and the labor intensity of the workers.

[0004] Therefore, in order to improve the service life of the lining plate of the rod mill and liberate productive forces, it is necessary to research and develop the lining plate material and preparation process of the rod mill, and strive to produce the lining plate of the rod mill with important academic significance and economic value to fill the gap in the industry. SUMMARY

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

[0006] To achieve the above object, the application provides a high-toughness wear-resistant lining plate material suitable for a rod mill, which comprises the following components in percentage by mass: 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 of iron.

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

[0008] Preferably, the hardness of the high-toughness wear-resistant lining plate material is >= 44.0 HRC.

[0009] Preferably, the impact toughness of the high-toughness wear-resistant lining plate material is >= 90.0 J / cm 2 .

[0010] Preferably, the tensile strength of the high-toughness wear-resistant lining plate material is >= 1300 MPa, and the yield strength is >= 1100 MPa.

[0011] The application further provides a preparation method of the high-toughness wear-resistant lining plate material suitable for a rod mill, which comprises the following steps:

[0012] (1) adding element raw materials and scrap steel to form a steelmaking raw material into a medium-frequency induction furnace to smelt into molten steel, and performing aluminum final deoxidization in the furnace before tapping;

[0013] (2) after the molten steel is tapped into a tundish, 0.5 Kg of a slag collecting agent is added and the tundish is started to be still, and after stilling, the slag is pulled out, the whole stilling + slag collecting + slag pulling process is greater than 3 minutes, and after the slag is pulled out for 2-3 times, the lining plate is cast into shape, and then the lining plate is sequentially subjected to 24 hours of slow cooling and open-air cooling, and after the open-air cooling, the cold cutting method is used to remove the lining plate riser, gate and sand, and polishing is performed;

[0014] (3) the polished lining plate is subjected to a heat treatment process to form a high-toughness lining plate, and the heat treatment process comprises 950 DEG C * 6 hours of heating and holding annealing, 890 DEG C * 6 hours of heating and holding air quenching cooling and 600 DEG C * 6 hours of heating and holding tempering.

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

[0016] Preferably, in step (1), the molten steel is subjected to aluminum final deoxidization in the furnace before tapping, and the tapping temperature is 1600-1620℃; the 1# rare earth alloy is added in the ladle, and the adding method is to place the 1# rare earth alloy at the bottom of the ladle, and a 0.2mm thick steel plate is used to cover above the alloy.

[0017] Preferably, in step (2), the molding process of the cast molding is designed as a wood mold + fat-hardened water glass sand molding process, wherein the weight ratio of raw materials in the fat-hardened water glass quartz sand is quartz sand: water glass: organic fat = 100:4:1; the slag blocking treatment is performed by using slag blocking cotton during the molten steel casting process, the casting temperature is 1520-1550℃, and the casting time of a single block lining plate is less than 1 minute.

[0018] Therefore, the high-toughness wear-resistant lining plate material suitable for a rod mill and the preparation method thereof have the following beneficial effects:

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

[0020] (2) The lining plate material prepared by the present application has low cost, good formability, high toughness, hardenability, and quenching, and is subjected to purification, modification and alloying treatment by using rare earth elements, so that the service life of the lining plate is long. 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; the number of equipment shutdown and maintenance is greatly reduced, and the comprehensive cost of production is reduced.

[0021] The technical solutions of the present application will be further described in detail below by means of the drawings and examples. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a lining plate working surface photo of the high-toughness wear-resistant lining plate material suitable for a rod mill prepared by the present application example one;

[0023] Figure 2 is a lining plate side photo of the high-toughness wear-resistant lining plate material suitable for a rod mill prepared by the present application example one;

[0024] Figure 3 is an annealing process curve in the preparation process of the high-toughness wear-resistant lining plate material of the present application example one;

[0025] Figure 4 is a quenching process curve in the preparation process of the high-toughness wear-resistant lining plate material of the present application example one;

[0026] Figure 5 is the tempering process curve in the preparation process of the high toughness wear-resistant lining plate material of embodiment one of the present application;

[0027] Figure 6 is the metallographic structure diagram of the high toughness wear-resistant lining plate material of embodiment one of the present application. DETAILED DESCRIPTION

[0028] The technical solutions of the present application will be further described below by means of the accompanying drawings and examples.

[0029] Unless otherwise defined, the technical terms or scientific terms used in the present application shall be understood as the usual meanings understood by those skilled in the art to which the present application belongs.

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the following will combine the drawings in the embodiments of the present application Figures 1 to 6 The technical solutions of the present application are described clearly and completely, obviously, the described embodiments are part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0031] The present application provides a high toughness wear-resistant lining plate material suitable for a rod mill, comprising 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 microstructure of the high toughness wear-resistant lining plate material is a mixture of tempered sorbite, bainite and carbide structure. The hardness of the high toughness wear-resistant lining plate material is ≧44.0HRC. The impact toughness of the high toughness wear-resistant lining plate material is ≧90.0J / cm 2 . The tensile strength of the high toughness wear-resistant lining plate material is ≧1300Mpa, and the yield strength is ≧1100Mpa.

[0033] Embodiment one

[0034] The present embodiment provides a high toughness wear-resistant lining plate material suitable for a rod mill, and the preparation method thereof comprises the following steps:

[0035] (1) High toughness wear-resistant material lining plate is smelted by 1000 Kg medium frequency induction furnace, and the raw materials for steelmaking are 930 Kg scrap steel, 8 Kg high-carbon ferromanganese alloy, 5 Kg ferrosilicon alloy, 45 Kg high-carbon ferrochrome alloy, 7 Kg molybdenum iron alloy, 5 Kg nickel plate, 5 Kg 1# rare earth alloy, 1 Kg aluminum wire and 1 Kg carbon additive. Aluminum is used for final deoxidization in the furnace before tapping, and the tapping temperature is 1600-1620℃. 1# rare earth alloy is added in the ladle, and the adding method is to put 1# rare earth alloy at the bottom of the ladle, and the upper part of the alloy is covered with a 0.2 mm thick steel plate.

[0036] (2) After the molten steel is poured into the tundish, 0.5 Kg of poly-slag is added and the static setting is started, and after the static setting, the slag is removed. The whole process of static setting + poly-slag + slag removal should be greater than 3 minutes, and the slag is removed 2-3 times before pouring. The molding process design is wood mold + fat hardened water glass sand molding process, and the ratio of fat hardened water glass quartz sand is quartz sand: water glass: organic fat, 100:4:1 by weight percentage. The molten steel pouring process uses slag blocking cotton for slag blocking treatment, the pouring temperature is 1520-1550℃, and the pouring time of single block lining plate is less than 1 minute. After the lining plate is poured, 24 hours of slow cooling is carried out, and after the slow cooling is finished, the box is opened for air cooling, and after the air cooling, the cold cutting method is used to remove the lining plate sprue, gate and clean the sand, and polishing is carried out, and the production lining plate is shown in Figure 1 and Figure 2 , and the actual chemical composition is shown in Table 1, and the rest is iron.

[0037] Table 1 Actual chemical composition of high toughness wear-resistant lining plate material

[0038]

[0039] (3) The polished lining plate is subjected to a heat treatment process to form a high toughness lining plate, and the heat treatment process includes 950℃ x 6 hours heating and holding annealing, 890℃ x 6 hours heating and holding air quenching cooling and 600℃ x 6 hours heating and holding tempering, and 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 structure detection

[0042] The heat treated lining plate is cut by a wire cutting machine tool, and the size of the cut sample is 20x20x15mm. The metallographic sample is ground by a belt grinding machine, 240#, 320#, 600# and 800# sandpaper, and then polished by a velvet polishing machine. The prepared metallographic sample is corroded by a 4% volume percentage nitric acid alcohol solution, and the metallographic structure is observed by a 4XC-TV metallographic microscope. The results are shown in Figure 6 .

[0043] As shown in the metallographic structure photo of the sample, after the lining plate is treated by 950℃ heating annealing + 890℃ heating air quenching + 600℃ heating air cooling tempering, the internal structure is tempered sorbite + bainite + carbide, which meets the requirements of the process design on the structure. The tempered sorbite + bainite + carbide structure can greatly improve the strength and toughness of the material, and can realize the reasonable matching of strength and toughness.

[0044] (II) Hardness detection

[0045] The heat treated lining plate is cut by a wire cutting machine tool, and the size of the cut sample is 20x20x15mm. The metallographic sample is ground by a belt grinding machine, 240#, 320#, 600# and 800# sandpaper, and then polished by a velvet polishing machine. The prepared metallographic sample is corroded by a 4% volume percentage nitric acid alcohol solution, and the metallographic structure is observed by a 4XC-TV metallographic microscope. The results are shown in

[0046] Table 2 Rockwell hardness of high strength and toughness wear-resistant lining plate material

[0047]

[0048] From the hardness results of the high strength and toughness lining plate in Table 2, it can be seen that the cross-section hardness of the high strength and toughness wear-resistant lining plate material after heat treatment is relatively uniform, with a change range of only 44.5-45.0HRC, and an average value of 44.78HRC. This shows that the high strength and toughness wear-resistant lining plate material has a small internal and external hardness fluctuation range after heat treatment, and the wear-resistant performance is stable during use, without local rapid wear phenomenon. Compared with the maximum value of 20HRC of the high manganese steel lining plate, the value increases by 24.78HRC, which increases by 123.9%.

[0049] (III) Impact performance of high strength and toughness wear-resistant lining plate material

[0050] In the center part of the cross-section of the heat treated lining plate, 3 impact blank samples with a size of 12x12x55mm are cut by a wire cutting machine tool, and then ground into standard unnotched impact samples with a size of 10x10x55mm. A N1500C material impact testing machine is used to conduct Charpy impact test on the sample, and the test results are shown in Table 3.

[0051] Table 3 Impact properties of high toughness wear-resistant liner material

[0052]

[0053] Table 3 shows that the high toughness wear-resistant liner material after heat treatment process, the unnotched impact toughness of the sample is greater than 90 J / cm 2 , the fluctuation range is 90.62-114.64 J / cm 2 , the average impact toughness is 99.66 J / cm 2 . Compared with the average impact toughness of 196 J / cm 2 of high manganese steel liner 2 , the value is reduced by 96.38 J / cm , but such impact toughness can fully meet the use requirements of the rod mill, indicating that the rod mill liner prepared by the material and heat treatment process will not be broken during use, and the equipment can be stably operated.

[0054] (IV) Tensile properties of high toughness wear-resistant liner

[0055] The tensile specimen blanks were taken from the 1 / 4 of the thickness of the liner after heat treatment process, and were processed into standard Φ10 mm standard tensile specimens by lathe and cylindrical grinding machine. The tensile test was carried out by using a 5989, 600 KN electronic universal material testing machine. In the experiment, 2 specimens were taken for each group to test the mechanical properties of the experimental steel, including tensile strength (Rm) and non-proportional elongation 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 toughness wear-resistant liner material

[0057] Sample No. Rm (MPa) Rp0.2 (MPa) A(％) Z(％) 1 1376 1183 8.10 8 2 1376 1189 7.0 7 Average 1376 1186 7.55 7.5

[0058] From the results in Table 4, the average tensile strength of the high toughness wear-resistant liner material after heat treatment process is 1376 MPa, the average yield strength is 1186 MPa, and the elongation and reduction of area are both greater than 7%. It shows that the designed high toughness wear-resistant liner material for rod mill after heat treatment process has high strength and certain plasticity, especially the yield strength. The yield strength of the high toughness wear-resistant liner is improved by 715-843 MPa compared with that of the high manganese steel liner. As we all know, the wear-resistant material liner first undergoes plastic deformation under the action of abrasive particles during work, and then grinding occurs when the plastic deformation reaches a certain degree, which affects the main index of plastic deformation, i.e. the yield strength of the liner material. Therefore, improving the yield strength of the liner material can avoid or delay the occurrence of grinding, reduce the wear of the liner, increase the service life of the liner, and make the equipment operate stably.

[0059] (V) the use effect of high toughness wear-resistant lining plate

[0060] In February 2024, a batch of high toughness wear-resistant lining plates were made according to the chemical composition range designed in Table 1 by using intermediate frequency induction furnace steelmaking and water glass sand forming process. The lining plates were treated by heat treatment process and installed in a Φ3.2x4.5m rod mill equipment of a company in March after the heat treatment process. Figure 3-5 The lining plates were used in February 2025 after the working surface of the lining plates was worn from the original thickness of 110mm to 35mm. During the use of the high toughness wear-resistant lining plates, no deformation, crushing and fracture of the lining plates occurred. After removing the downtime for maintenance caused by other reasons during production, the actual use time of the high toughness wear-resistant lining plates was 11 months. Compared with the use time of the original high manganese steel lining plates, the use time was prolonged by 6-7 months, and the service life was 2.2-2.75 times that of the high manganese steel. The number of equipment downtime for maintenance was greatly reduced, and the comprehensive cost of production was reduced.

[0061] Therefore, the high toughness wear-resistant lining plate material suitable for a rod mill and the preparation method thereof have low cost, good formability, high toughness and hardenability, and the lining plates are treated by purification, modification and alloying treatment of rare earth elements, so that the long service life of the lining plates is realized.

[0062] Finally, it should be noted that: the above examples are only used to illustrate the technical solutions of the present application but not to limit it. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can still be modified or replaced by equivalents, and these modifications or replacements cannot make the modified technical solutions deviate from the spirit and scope of the technical solutions of the present application.

Claims

1. A high-strength, tough, and wear-resistant liner material suitable for rod mills, characterized in that, It contains 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, with the balance being iron.

2. The high-strength, tough, and wear-resistant liner material suitable for rod mills according to claim 1, characterized in that, The microstructure of the high-strength, tough, and wear-resistant liner material is a mixture of tempered sorbite, bainite, and carbide structures.

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

4. The high-strength, tough, and wear-resistant liner material suitable for rod mills according to claim 1, characterized in that, The impact toughness of the high-strength, tough, and wear-resistant lining material is ≥90 J / cm. 2 .

5. The high-strength, tough, and wear-resistant liner material suitable for rod mills according to claim 1, characterized in that, The high-strength, tough, and wear-resistant liner material has a tensile strength ≥1300 MPa and a yield strength ≥1100 MPa.

6. A method for preparing a high-strength, tough, and wear-resistant liner material suitable for rod mills as described in any one of claims 1-5, characterized in that, Includes the following steps: (1) Adding element raw materials and scrap steel to form steelmaking raw materials are put into medium frequency induction furnace to smelt into molten steel. Before tapping the steel, aluminum final deoxidation is carried out in the furnace. (2) After the molten steel is poured into the tundish, 0.5 kg of slag-aggregating agent is added and the slag is removed. The entire process of slag removal, slag aggregation and slag removal takes more than 3 minutes. After slag removal 2-3 times, the steel is cast into a liner. The liner is then subjected to slow cooling for 24 hours and air cooling after opening the tundish. After air cooling, the riser and gate of the liner are removed by cold cutting and the sand is cleaned and polished. (3) The polished liner is subjected to a heat treatment process to form a high-strength and tough liner. The heat treatment process includes annealing at 950℃ for 6 hours, air quenching and cooling at 890℃ for 6 hours, and tempering at 600℃ for 6 hours.

7. The method for preparing a high-strength, tough, and wear-resistant liner material suitable for rod mills according to claim 6, characterized in that, In step (1), the added elemental raw materials are high-carbon ferromanganese alloy, ferrosilicon alloy, high-carbon ferrochrome alloy, ferromolybdenum alloy, nickel plate, No. 1 rare earth alloy, aluminum wire and carbon additive, wherein the No. 1 rare earth alloy is a Si-Mg-Re alloy with a rare earth content of 30%.

8. The method for preparing a high-strength, tough, and wear-resistant liner material suitable for rod mills according to claim 7, characterized in that, In step (1), aluminum final deoxidation is carried out in the furnace before the molten steel is tapped, and the tapping temperature is 1600-1620℃; the No. 1 rare earth alloy is added in the ladle. The addition method is to place the No. 1 rare earth alloy at the bottom of the ladle and cover the No. 1 rare earth alloy with a 0.2mm thick steel plate.

9. The method for preparing a high-strength, tough, and wear-resistant liner material suitable for rod mills according to claim 6, characterized in that, In step (2), the molding process is designed as a wooden mold + resin-cured water glass quartz sand molding process. The weight ratio of raw materials in the resin-cured water glass quartz sand is quartz sand: water glass: organic resin = 100:4:

1. Slag-blocking cotton is used for slag blocking treatment during the steel casting process. The initial casting temperature is 1520-1550℃, and the casting time of a single liner is less than 1 minute.

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