A high wear-resistant hypereutectic high-chromium white cast iron, its preparation method and application

Abstract

This invention relates to the field of cast iron materials, and more particularly to a high-wear-resistant hypereutectic high-chromium white cast iron, its preparation method, and its applications. The high-chromium white cast iron, by mass percentage, has the following chemical composition: C: 4.2%-4.9%, Si: 0.5%-1.0%, Mn: 1.5%-2.1%, Cr: 32%-35%, Ni: 1.0%-1.5%, Mo: 1.0%-2%, W: 0.5%-1.2%, S≤0.1%, P≤0.1%, RE≤0.01%, Nb≤0.3%, and the balance being Fe and unavoidable impurities. The high-chromium white cast iron obtained by this invention exhibits good toughness, combining high wear resistance and high hardness, making it more suitable for heavy wear conditions. This invention effectively solves the problems of insufficient wear resistance in the flow components of slurry pumps under heavy wear conditions and the poor toughness of the high-chromium cast iron used in the preparation of slurry pumps in the prior art.

Description

Technical Field

[0001] This invention relates to the field of cast iron materials, and in particular to a high wear-resistant hypereutectic high-chromium white cast iron, its preparation method, and its application. Background Technology

[0002] High-chromium cast iron has seen rapid development in production and application as a wear-resistant and corrosion-resistant material. Because it contains a large amount of high-hardness M7C3 type carbides, it has excellent wear resistance. At the same time, the chromium element dissolved in the matrix can improve the material's corrosion resistance. To date, it has become one of the most widely used wear-resistant and corrosion-resistant cast irons in the world.

[0003] The operating environment of slurry pumps is extremely complex and harsh, resulting in severe wear on the flow-through components. This is especially true in mineral processing, where the materials are hard, large, and uneven in shape. As the main equipment for transporting ore, the flow-through components of slurry pumps are not only subject to erosion wear, abrasive wear, surface fatigue wear, and corrosive wear, but also to corrosion and wear from solid particles and the medium itself. This can easily lead to slurry pump failure, affecting the normal operation of the entire mineral processing system and causing huge losses.

[0004] Currently, wear-resistant slurry pump flow components both domestically and internationally generally use BTMCr26 and 15CrMo3, but these components can only withstand general wear conditions. Under heavy wear conditions, their wear resistance remains poor, resulting in a short service life. This has become a problem for slurry pump manufacturers and users. Existing technologies have reported the use of ultra-high wear-resistant hypereutectic high-chromium cast iron as flow components, but due to its high carbon content and large proportion of carbides, its toughness is particularly poor. The complex shape of the slurry pump flow components also makes the castings particularly prone to cracking. Therefore, it is necessary to improve the toughness of the material itself while meeting high wear resistance requirements, thereby increasing the yield and ensuring stable production processes. Thus, developing a cast iron material that is easy to operate and possesses high wear resistance and high toughness is of great significance for the application of slurry pumps. Summary of the Invention

[0005] In view of the problems in the prior art, such as insufficient wear resistance of the flow components of slurry pumps under heavy wear conditions, which affects the performance of slurry pumps, and the poor toughness of the high-chromium cast iron used to manufacture slurry pumps, this invention provides a high wear-resistant hypereutectic high-chromium white cast iron, its preparation method and application.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] The first aspect of this invention provides a high wear-resistant hypereutectic high-chromium white cast iron, wherein the high-chromium white cast iron has the following chemical composition by mass percentage: C: 4.2%-4.9%, Si: 0.5%-1.0%, Mn: 1.5%-2.1%, Cr: 32%-35%, Ni: 1.0%-1.5%, Mo: 1.0%-2%, W: 0.5%-1.2%, S≤0.1%, P≤0.1%, RE≤0.01%, Nb≤0.3%, and the balance being Fe and unavoidable impurities.

[0008] Compared to existing technologies, this invention provides a high-wear-resistant hypereutectic high-chromium white cast iron. The high-wear-resistant hypereutectic high-chromium white cast iron is prepared using specific raw material compositions. The high-chromium white cast iron obtained by this invention contains the element W, a strong carbide element. Its carbides can reach a hardness of approximately HRC75 and exhibit good stability, distributing uniformly in the matrix and carbides. The W carbides are predominantly WC. 1-x W6C 2.54 The presence of W in the form of CW3 can simultaneously increase the hardness of both the matrix and carbides. Furthermore, the addition of elements such as Mo and Ni, which improve and refine the microstructure of castings, can further improve the matrix structure and carbide morphology, thereby enhancing the overall performance of the castings.

[0009] Because the solubility of RE in austenite is very low, it is mostly enriched in the solution at the dendrite front of austenite, forming a compositionally supercooled zone. This promotes the multi-directional growth of austenite dendrites and reduces the dendrite spacing. During austenite growth, the dendrites interlock to form a structure that hinders the formation of eutectic carbides. Simultaneously, RE atoms readily adsorb onto the surface of newly formed carbides, hindering their preferential growth rate and making it difficult for them to connect into a closed network. This improves the toughness of high-chromium white cast iron and further refines its matrix structure, promoting the transformation of eutectic carbides from elongated to agglomerated forms, thus increasing the hardness of the resulting high-chromium white cast iron.

[0010] Furthermore, niobium (Nb) can refine austenite and carbides, significantly reducing inclusions and improving metallurgical quality, thereby enhancing the wear resistance of the resulting high-chromium white cast iron. Niobium is a strong carbide-forming element with a higher affinity for carbon than iron and chromium. Nb carbides can act as crystal nuclei, improving the morphology and distribution of carbides. Simultaneously, the segregation of niobium in austenite grains hinders the growth of matrix grains, thus refining the grains and making the microstructure of the resulting high-chromium white cast iron more uniform. This, in turn, improves its wear resistance and hardness, meeting the requirements for a high-wear-resistant and high-hardness high-chromium cast iron.

[0011] Preferably, the microstructure of the high-chromium white cast iron is eutectic carbides + martensite + retained austenite + secondary carbides.

[0012] A second aspect of the present invention provides a method for preparing the aforementioned high wear-resistant hypereutectic high-chromium white cast iron, comprising the following steps:

[0013] Step 1: Weigh each raw material component according to the designed proportions, and add them in the order of scrap steel, ferrochrome, ferrosilicon, ferromanganese, nickel plate, ferromolybdenum and ferrotungsten. Melt the materials and control the furnace temperature at 1525℃-1560℃ to obtain molten iron.

[0014] Step 2: Place the rare earth composite modifier at the bottom of the preheated ladle, cover it with a layer of heat insulation material, melt the iron, mold it with resin sand, and pour it to obtain the casting.

[0015] Step 3: Heat treat the casting, remove it from the furnace and air cool it to obtain the high wear-resistant hypereutectic high-chromium white cast iron.

[0016] Preferably, the high wear-resistant hypereutectic high-chromium white cast iron comprises the following raw material components by mass percentage: 33%-35% scrap steel, 56%-58% ferrochrome, 0.6%-0.7% ferrosilicon, 2.3%-2.6% ferromanganese, 1.2%-1.4% nickel plate, 2.4%-2.7% ferromolybdenum, 0.7%-0.9% ferrotungsten, and 1.3%-1.5% rare earth composite modifier.

[0017] More preferably, the rare earth composite modifier comprises a rare earth ferrosilicon and ferroniobium alloy with a mass ratio of 0.3-0.4:1.

[0018] More preferably, the RE content in the rare earth ferrosilicon is 23%-27%.

[0019] More preferably, the RE is any one or two of Ce, Y, or Er.

[0020] More preferably, the Nb content in the ferroniobium is 60%-70%.

[0021] Preferably, in step one, the melting temperature is 1580℃-1600℃, and the melting time is 1h-3h.

[0022] Preferably, in step two, the amount of resin added in the resin sand molding process is 1.0%-1.5% of the weight of the molding sand.

[0023] Preferably, in step two, the amount of curing agent added to the resin sand molding process is 35%-45% of the weight of the resin.

[0024] Preferably, in step two, the iron sand ratio in the resin sand molding is 1:6.8-7.2.

[0025] More preferably, the molding sand is scrubbing sand.

[0026] More preferably, the resin is a furan resin.

[0027] More preferably, the curing agent is a sulfonic acid curing agent.

[0028] Preferably, in step two, the distance between the sand box and the casting in the resin sand molding process is ≥100mm.

[0029] Preferably, in step two, the heat insulation material is perlite.

[0030] Preferably, in step two, the thickness of the insulation material is 10cm-15cm.

[0031] Preferably, in step two, the pouring temperature is 1400℃-1420℃ and the pouring time is ≤20min.

[0032] Preferably, in step three, the heat treatment temperature is 950℃-1020℃, and the heat treatment holding time is 5h-7h.

[0033] More preferably, the heat treatment employs a slow heating method to raise the temperature to 950℃-1020℃, with a heating rate ≤40℃ / h.

[0034] The third aspect of this invention provides the application of the high wear-resistant hypereutectic high-chromium white cast iron described above, or the high wear-resistant hypereutectic high-chromium white cast iron prepared by the preparation method of the high wear-resistant hypereutectic high-chromium white cast iron described above, in slurry pumps.

[0035] In summary, this invention provides a high-wear-resistant hypereutectic high-chromium white cast iron. By controlling the formation of the metallographic structure of the high-chromium white cast iron through specific composition, the resulting high-chromium white cast iron exhibits better toughness and is more suitable for complex and harsh working environments. The high-chromium white cast iron obtained by this invention possesses excellent wear resistance and high hardness, reaching up to 68 HRC. Compared with existing high-chromium cast irons, its wear resistance can reach 2 times or even more than that of BTMCr26. Attached Figure Description

[0036] Figure 1 The image shows the metallographic structure of the high wear-resistant hypereutectic high-chromium white cast iron obtained in Example 1. Figure 1 Figure (a) shows the metallographic structure magnified 100 times. Figure 1 Figure (b) shows the metallographic structure magnified 400 times. Detailed Implementation

[0037] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] This embodiment provides a high wear-resistant hypereutectic high-chromium white cast iron, specifically including the following steps:

[0040] The raw materials for the high wear-resistant hypereutectic high-chromium white cast iron include the following components by mass percentage: 33.67% scrap steel, 57% ferrochrome, 0.65% ferrosilicon, 2.5% ferromanganese, 1.3% nickel plate, 2.6% ferromolybdenum, 0.88% ferrotungsten, and 1.4% rare earth composite modifier.

[0041] The rare earth composite modifier is a mixture of rare earth ferrosilicon and ferroniobium with a mass ratio of 0.4:1 and a particle size of 7mm-9mm.

[0042] The molding sand used in the resin sand process is scrubbing sand, and the amount of furan resin added is 1.3% of the weight of the molding sand; the amount of sulfonic acid curing agent added is 40% of the weight of the furan resin, and the iron sand ratio is controlled at 1:7; the distance between the sand box and the casting is 120mm.

[0043] Step 1: Weigh each raw material component according to the designed proportions, and add them in the order of scrap steel, high-carbon ferrochrome, ferrosilicon, ferromanganese, nickel plate, ferromolybdenum and ferrotungsten. Melt at 1580℃ and control the furnace exit temperature at 1550℃ to obtain molten iron.

[0044] Step 2: Place the rare earth composite modifier at the bottom of the heated ladle, cover it with perlite to a thickness of 14cm, mold the molten iron using resin sand process, pour it at 1410℃ for 18 minutes, and the casting is completed.

[0045] Step 3: Place the casting into a heat treatment furnace, heat the casting to 1000℃ at a heating rate of 35℃ / h, hold for 6 hours, remove from the furnace and air cool to obtain the high wear-resistant hypereutectic high-chromium white cast iron.

[0046] Example 2

[0047] This embodiment provides a high wear-resistant hypereutectic high-chromium white cast iron, specifically including the following steps:

[0048] The raw materials for the high wear-resistant hypereutectic high-chromium white cast iron include the following components by mass percentage: 34.05% scrap steel, 57.06% ferrochrome, 0.6% ferrosilicon, 2.4% ferromanganese, 1.3% nickel plate, 2.4% ferromolybdenum, 0.79% ferrotungsten, and 1.4% rare earth composite modifier.

[0049] The rare earth composite modifier is a mixture of rare earth ferrosilicon and ferroniobium with a mass ratio of 0.35:1 and a particle size of 7mm-9mm.

[0050] The molding sand used in the resin sand process is scrubbing sand, and the amount of furan resin added is 1.5% of the weight of the molding sand; the amount of sulfonic acid curing agent added is 38% of the weight of the furan resin, and the iron sand ratio is controlled at 1:6.9; the distance between the sand box and the casting is 120mm.

[0051] Step 1: Weigh each raw material component according to the designed proportions, and add them in the order of scrap steel, high-carbon ferrochrome, ferrosilicon, ferromanganese, nickel plate, ferromolybdenum and ferrotungsten. Melt at 1590℃ and control the furnace exit temperature at 1550℃ to obtain molten iron.

[0052] Step 2: Place the rare earth composite modifier at the bottom of the heated ladle, cover it with perlite to a thickness of 13cm, mold the molten iron using resin sand process, pour it at 1415℃ for 18 minutes, and the casting is obtained.

[0053] Step 3: Place the casting into a heat treatment furnace, heat the casting to 1010℃ at a heating rate of 40℃ / h, hold for 6.5h, remove from the furnace and air cool to obtain the high wear-resistant hypereutectic high-chromium white cast iron.

[0054] Example 3

[0055] This embodiment provides a high wear-resistant hypereutectic high-chromium white cast iron, specifically including the following steps:

[0056] The raw materials for the high wear-resistant hypereutectic high-chromium white cast iron include the following components by mass percentage: 33.71% scrap steel, 57.03% ferrochrome, 0.65% ferrosilicon, 2.5% ferromanganese, 1.3% nickel plate, 2.6% ferromolybdenum, 0.84% ​​ferrotungsten, and 1.37% rare earth composite modifier.

[0057] The rare earth composite modifier is a mixture of rare earth ferrosilicon and ferroniobium with a mass ratio of 0.35:1 and a particle size of 7mm-9mm.

[0058] The molding sand used in the resin sand process is scrubbing sand, and the amount of furan resin added is 1.27% of the weight of the molding sand; the amount of sulfonic acid curing agent added is 43% of the weight of the furan resin, and the iron sand ratio is controlled at 1:7; the distance between the sand box and the casting is 120mm.

[0059] Step 1: Weigh each raw material component according to the designed proportions, and add them in the order of scrap steel, high-carbon ferrochrome, ferrosilicon, ferromanganese, nickel plate, ferromolybdenum and ferrotungsten. Melt at 1580℃ and control the furnace exit temperature at 1535℃ to obtain molten iron.

[0060] Step 2: Place the rare earth composite modifier at the bottom of the heated ladle, cover it with perlite to a thickness of 14cm, mold the molten iron using resin sand process, pour it at 1410℃ for 17 minutes, and the casting is obtained.

[0061] Step 3: Place the casting into a heat treatment furnace, heat the casting to 1010℃ at a heating rate of 38℃ / h, hold for 6 hours, remove from the furnace and air cool to obtain the high wear-resistant hypereutectic high-chromium white cast iron.

[0062] Example 4

[0063] This embodiment provides a high wear-resistant hypereutectic high-chromium white cast iron, specifically including the following steps:

[0064] The raw materials for the high wear-resistant hypereutectic high-chromium white cast iron include the following components by mass percentage: 34.55% scrap steel, 56% ferrochrome, 0.7% ferrosilicon, 2.5% ferromanganese, 1.3% nickel plate, 2.7% ferromolybdenum, 0.9% ferrotungsten, and 1.35% rare earth composite modifier.

[0065] The rare earth composite modifier is a mixture of rare earth ferrosilicon and ferroniobium with a mass ratio of 0.35:1 and a particle size of 7mm-9mm.

[0066] The molding sand used in the resin sand process is scrubbing sand, and the amount of furan resin added is 1.1% of the weight of the molding sand; the amount of sulfonic acid curing agent added is 43.6% of the weight of the furan resin, and the iron sand ratio is controlled at 1:6.9; the distance between the sand box and the casting is 115mm.

[0067] Step 1: Weigh each raw material component according to the designed proportions, and add them in the order of scrap steel, high-carbon ferrochrome, ferrosilicon, ferromanganese, nickel plate, ferromolybdenum and ferrotungsten. Melt at 1580℃ and control the furnace exit temperature at 1550℃ to obtain molten iron.

[0068] Step 2: Place the rare earth composite modifier at the bottom of the heated ladle, cover it with perlite to a thickness of 13cm, mold the molten iron using resin sand process, pour it at 1415℃ for 18 minutes, and the casting is obtained.

[0069] Step 3: Place the casting into a heat treatment furnace, heat the casting to 990°C at a heating rate of 35°C / h, hold for 6.5h, remove from the furnace and air cool to obtain the high wear-resistant hypereutectic high-chromium white cast iron.

[0070] Example 5

[0071] This embodiment provides a high wear-resistant hypereutectic high-chromium white cast iron, specifically including the following steps:

[0072] The raw materials for the high wear-resistant hypereutectic high-chromium white cast iron include the following components by mass percentage: 33.67% scrap steel, 57% ferrochrome, 0.65% ferrosilicon, 2.5% ferromanganese, 1.3% nickel plate, 2.6% ferromolybdenum, 0.88% ferrotungsten, and 1.4% rare earth composite modifier.

[0073] The rare earth composite modifier is a mixture of rare earth ferrosilicon and ferroniobium with a mass ratio of 0.4:1 and a particle size of 7mm-9mm.

[0074] The molding sand used in the resin sand process is scrubbing sand, and the amount of furan resin added is 1.15% of the weight of the molding sand; the amount of sulfonic acid curing agent added is 38.7% of the weight of the furan resin, and the iron sand ratio is controlled at 1:7; the distance between the sand box and the casting is 120mm.

[0075] Step 1: Weigh each raw material component according to the designed proportions, and add them in the order of scrap steel, high-carbon ferrochrome, ferrosilicon, ferromanganese, nickel plate, ferromolybdenum and ferrotungsten. Melt at 1580℃ and control the furnace exit temperature at 1550℃ to obtain molten iron.

[0076] Step 2: Place the rare earth composite modifier at the bottom of the heated ladle, cover it with perlite to a thickness of 14cm, mold the molten iron using resin sand process, pour it at 1410℃ for 18 minutes, and the casting is completed.

[0077] Step 3: Place the casting into a heat treatment furnace, heat the casting to 1020℃ at a heating rate of 40℃ / h, hold for 6h, remove from the furnace and air cool to obtain the high wear-resistant hypereutectic high-chromium white cast iron.

[0078] Comparative Example 1

[0079] This comparative example provides a high wear-resistant hypereutectic high-chromium white cast iron, which differs from Example 1 in that the rare earth composite modifier is replaced with an equal amount of rare earth ferrosilicon, while other conditions and compositions remain unchanged. Specifically, it includes the following steps:

[0080] The raw materials for the high wear-resistant hypereutectic high-chromium white cast iron include the following components by mass percentage: 33.67% scrap steel, 57% ferrochrome, 0.65% ferrosilicon, 2.5% ferromanganese, 1.3% nickel plate, 2.6% ferromolybdenum, 0.88% ferrotungsten, and 1.4% rare earth composite modifier.

[0081] The rare earth composite modifier is rare earth ferrosilicon with a particle size of 7mm-9mm.

[0082] The molding sand used in the resin sand process is scrubbing sand, and the amount of furan resin added is 1.3% of the weight of the molding sand; the amount of sulfonic acid curing agent added is 40% of the weight of the furan resin, and the iron sand ratio is controlled at 1:7; the distance between the sand box and the casting is 120mm.

[0083] Step 1: Weigh each raw material component according to the designed proportions, and add them in the order of scrap steel, high-carbon ferrochrome, ferrosilicon, ferromanganese, nickel plate, ferromolybdenum and ferrotungsten. Melt at 1580℃ and control the furnace exit temperature at 1550℃ to obtain molten iron.

[0084] Step 2: Place the rare earth composite modifier at the bottom of the heated ladle, cover it with perlite to a thickness of 14cm, mold the molten iron using resin sand process, pour it at 1410℃ for 18 minutes, and the casting is completed.

[0085] Step 3: Place the casting into a heat treatment furnace, heat the casting to 1000℃ at a heating rate of 35℃ / h, hold for 6 hours, remove from the furnace and air cool to obtain the high wear-resistant hypereutectic high-chromium white cast iron.

[0086] Comparative Example 2

[0087] This comparative example provides a high wear-resistant hypereutectic high-chromium white cast iron. The difference from Example 1 is that the rare earth composite modifier is replaced with an equal amount of a mixture of rare earth ferrosilicon and ferrotitanium, while other conditions and compositions remain unchanged. Specifically, it includes the following steps:

[0088] The raw materials for the high wear-resistant hypereutectic high-chromium white cast iron include the following components by mass percentage: 33.67% scrap steel, 57% ferrochrome, 0.65% ferrosilicon, 2.5% ferromanganese, 1.3% nickel plate, 2.6% ferromolybdenum, 0.88% ferrotungsten, and 1.4% rare earth composite modifier.

[0089] The rare earth composite modifier is a mixture of rare earth ferrosilicon and ferrotitanium in a mass ratio of 0.35:1, with a particle size of 7mm-9mm.

[0090] The molding sand used in the resin sand process is scrubbing sand, and the amount of furan resin added is 1.3% of the weight of the molding sand; the amount of sulfonic acid curing agent added is 40% of the weight of the furan resin, and the iron sand ratio is controlled at 1:7; the distance between the sand box and the casting is 120mm.

[0091] Step 1: Weigh each raw material component according to the designed proportions, and add them in the order of scrap steel, high-carbon ferrochrome, ferrosilicon, ferromanganese, nickel plate, ferromolybdenum and ferrotungsten. Melt at 1580℃ and control the furnace exit temperature at 1550℃ to obtain molten iron.

[0092] Step 2: Place the rare earth composite modifier at the bottom of the heated ladle, cover it with perlite to a thickness of 14cm, mold the molten iron using resin sand process, pour it at 1410℃ for 18 minutes, and the casting is completed.

[0093] Step 3: Place the casting into a heat treatment furnace, heat the casting to 1000℃ at a heating rate of 35℃ / h, hold for 6 hours, remove from the furnace and air cool to obtain the high wear-resistant hypereutectic high-chromium white cast iron.

[0094] Comparative Example 3

[0095] This comparative example provides a commercially available hypereutectic high-chromium white cast iron, BTMCr26.

[0096] To further demonstrate the technical effects of the present invention, wear tests (according to GB12444-2006 standard) and hardness tests (according to GB / T8263-2010 standard) were conducted on the high-chromium white cast iron obtained in Examples 1-5 and Comparative Examples 1-3. The test results are shown in Tables 1 and 2. At the same time, the present invention also conducted fracture toughness tests (according to GB / T21143-2014 standard) on the high-chromium white cast iron obtained in Examples 1-5 and Comparative Examples 1-3. The test results are shown in Table 3.

[0097] The present invention also conducted metallographic analysis on the high wear-resistant hypereutectic high-chromium white cast iron obtained in Example 1, and the test results are as follows: Figure 1 As shown.

[0098] Table 1 Wear test results

[0099]

[0100]

[0101] Table 2 Hardness Test Results

[0102]

[0103] Table 3. Fracture toughness test results

[0104]

[0105]

[0106] As can be seen from Tables 1 and 2, the high wear-resistant hypereutectic high-chromium white cast iron provided in Examples 1-5 of the present invention exhibits excellent wear resistance, reaching twice or even more than that of BTMCr26. Furthermore, the compositional analysis and hardness tests of the high-chromium cast iron obtained in each example and comparative example show that the Rockwell hardness of the high-chromium cast iron obtained in the examples of the present invention is ≥66.8 HRC, indicating that the high-chromium cast iron obtained in the examples of the present invention has a high Rockwell hardness. In contrast, the erosion wear resistance of the high-chromium cast iron obtained in Comparative Examples 1-2 is only 1.3-1.4 times that of BTMCr26, indicating that the wear resistance of the high-chromium cast iron obtained in Comparative Examples 1-2 is inferior to that of the high-chromium cast iron obtained in the examples. Even the highest Rockwell hardness of the high-chromium cast iron in the comparative examples only reaches 62.3 HRC, which is significantly lower than that of the high-chromium cast iron obtained in the examples.

[0107] As can be seen from Table 3, the high wear-resistant hypereutectic high-chromium white cast iron provided in Examples 1-5 of this invention has high fracture toughness. This is because the obtained high-chromium white cast iron contains retained austenite. The retained austenite has good toughness, and when crack propagation encounters the tough phase, the resistance suddenly increases, thereby preventing cracking and increasing K. Ic value.

[0108] According to the present invention, the metallographic structure test diagram of the high wear-resistant hypereutectic high-chromium white cast iron obtained in Example 1 is shown in the figure. Figure 1 As can be seen, the chromium and tungsten carbides (white blocky structure) are lath-shaped and have a relatively small degree of fragmentation on the matrix. Martensitic matrix and some retained austenite exist around the carbides, and fine secondary carbides are distributed on the martensitic matrix. The dispersed secondary carbides further improve the strength and wear resistance of the matrix. This invention, through metallographic modification treatment of cast iron, results in a significant refinement of dendritic austenite, a significant reduction in the number of nodular austenite, and rounded edges of the carbides. After quenching heat treatment, the matrix structure is significantly refined, the carbide distribution is more uniform, and the carbide morphology is greatly improved, with a significant reduction in coarse carbides and sharp-angled carbides.

[0109] In summary, this invention provides a high-wear-resistant hypereutectic high-chromium white cast iron. By utilizing special components to regulate the formation of the metallographic structure of the high-chromium white cast iron, the resulting high-chromium white cast iron exhibits excellent wear resistance and high Rockwell hardness, meeting the material requirements of various complex working conditions. This effectively solves the problems in the prior art where the flow components of slurry pumps have insufficient wear resistance under heavy wear conditions, thus affecting the performance of the slurry pump, and the poor toughness of the high-chromium cast iron used in the preparation of slurry pumps.

[0110] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions or improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A high abrasion resistant hypereutectic high chromium white cast iron, characterized by: The weight percentage of its components are: C: 4.2%-4.9%, Si: 0.5%-1.0%, Mn: 1.5%-2.1%, Cr: 32%-35%, Ni: 1.0%-1.5%, Mo: 1.0%-2%, W: 0.5%-1.2%, S≤0.1%, P≤0.1%, RE≤0.01%, Nb≤0.3% and the balance of Fe and inevitable impurities; the metallographic structure of the high-chromium white cast iron is eutectic carbide + martensite + residual austenite + secondary carbide; The preparation method of the high-wear-resistance peritectic high-chromium white cast iron comprises the following steps: Step one, according to the designed proportion, each raw material component is weighed, and then sequentially added according to the order of scrap steel, chromium iron, ferrosilicon, ferromanganese, nickel plate, molybdenum iron and tungsten iron, and then smelted, and the temperature of the molten iron is controlled at 1525-1560℃; Step two, the rare earth composite modifier is placed at the bottom of the preheated ladle, and a layer of heat insulation material is covered thereon, and then the molten iron is molded by resin sand and poured to obtain a casting; Step three, the casting is subjected to heat treatment, and then discharged and air-cooled to obtain the high-wear-resistance peritectic high-chromium white cast iron. The rare earth composite modifier comprises rare earth ferrosilicon and niobium iron alloy with a mass ratio of 0.3-0.4:1; the content of RE in the rare earth ferrosilicon is 23%-27%; and the content of Nb in the niobium iron is 60%-70%.

2. A method of producing the high abrasion resistant hypereutectic high chromium white cast iron according to claim 1, characterized in that: The preparation method comprises the following steps: Step one, according to the designed proportion, each raw material component is weighed, and then sequentially added according to the order of scrap steel, chromium iron, ferrosilicon, ferromanganese, nickel plate, molybdenum iron and tungsten iron, and then smelted, and the temperature of the molten iron is controlled at 1525-1560℃; Step two, the rare earth composite modifier is placed at the bottom of the preheated ladle, and a layer of heat insulation material is covered thereon, and then the molten iron is molded by resin sand and poured to obtain a casting; Step three, the casting is subjected to heat treatment, and then discharged and air-cooled to obtain the high-wear-resistance peritectic high-chromium white cast iron.

3. The method of producing high abrasion resistant hypereutectic high chromium white cast iron according to claim 2, characterized in that: The high-wear-resistance peritectic high-chromium white cast iron comprises the following raw material components with the following mass percentages: scrap steel 33%-35%, chromium iron 56%-58%, ferrosilicon 0.6%-0.7%, ferromanganese 2.3%-2.6%, nickel plate 1.2%-1.4%, molybdenum iron 2.4%-2.7%, tungsten iron 0.7%-0.9% and rare earth composite modifier 1.3%-1.5%.

4. The method of producing high abrasion resistant hypereutectic high chromium white cast iron according to claim 2, characterized in that: In step two, the resin is added in the resin sand molding in an amount of 1.0%-1.5% of the weight of the molding sand; and / or In step two, the curing agent is added in the resin sand molding in an amount of 35%-45% of the weight of the resin; and / or In step two, the iron sand ratio in the resin sand molding is 1:6.8-7.

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5. The method of producing high abrasion resistant hypereutectic high chromium white cast iron according to claim 2, characterized in that: In step two, the heat insulation material is perlite; and / or In step two, the covering thickness of the heat insulation material is 10-15cm; and / or In step two, the pouring temperature is 1400-1420℃, and the pouring time is ≤20min; and / or In step three, the heat treatment temperature is 950-1020℃, and the heat treatment holding time is 5-7h.

6. The method of producing high abrasion resistant hypereutectic high chromium white cast iron according to claim 2, characterized in that: The heat treatment is raised to 950-1020℃ by slow heating, and the heating rate is ≤40℃ / h.

7. Use of the high abrasion resistant hypereutectic high chromium white cast iron according to claim 1 or of the high abrasion resistant hypereutectic high chromium white cast iron produced by the method according to any one of claims 2 to 6 in a slurry pump.

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