Steel-based composite material and preparation method and application thereof

Abstract

The invention discloses a steel-based composite material and a preparation method and application thereof, and relates to the technical field of steel-based composite materials. A preparation method of a steel-based composite material comprises the following steps that (1) carbon powder and metal powder are evenly mixed according to the atomic ratio of 1: 1, and initial powder is obtained; (2) pressing the initial powder into spherical particles, then adding a binder, uniformly mixing to obtain a mixture, then carrying out cold press molding on the mixture, and curing to obtain a prefabricated blank; (3) pre-sintering the prefabricated green body at 150-200 DEG C to obtain a sintered green body; and (4) casting the sintered green body by adopting a melt to obtain the steel-based composite material. According to the method, powder metallurgy and casting processes are combined, and the steel-based composite material reinforced by two or more hard particles such as TiC, WC, CrxCy, VC, MoC and NbC is obtained in situ.

Description

Technical Field

[0001] The present invention relates to the technical field of steel matrix composites, and particularly relates to a steel matrix composite material, a preparation method thereof, and an application thereof. Background Art

[0002] With the increasing complexity of service conditions and the high efficiency of equipment operation, traditional single wear-resistant steel materials can no longer meet the higher performance requirements in the wear-resistant field. Steel matrix composites with both the good toughness and plasticity of steel materials and the high hardness and high wear resistance of hard particles are the first choice to replace traditional single steel wear-resistant materials. At present, the trial application of compounding of core vulnerable parts such as cones, liners, and plate hammers in mine crushing equipment has effectively extended the service life of vulnerable parts and significantly improved the crushing and grinding efficiency of the equipment. However, medium and large parts such as cones, liners, and plate hammers only account for about 30% of the wear-resistant steel material field. The problem of difficulty in compounding medium and small thin-walled parts with a high proportion in the wear-resistant steel material field, such as impellers, pump casings, cutter teeth, and hob cutters, has always restricted the upgrading and replacement of wear-resistant steel materials.

[0003] Therefore, it is very necessary for the development of the wear-resistant field to realize the compounding of medium and small wear-resistant steel parts and improve their service life. Summary of the Invention

[0004] The purpose of the present invention is to provide a steel matrix composite material, a preparation method thereof, and an application thereof by overcoming the deficiencies of the prior art. The present invention combines powder metallurgy and casting processes to in-situ obtain a steel matrix composite material reinforced by two or more hard particles such as TiC, WC, Cr x C y , VC, MoC, NbC, etc.

[0005] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0006] In the first aspect, the present invention also provides a preparation method of a steel matrix composite material, including the following steps:

[0007] (1) Mix carbon powder and metal powder evenly according to an atomic ratio of 1:1 to obtain initial powder;

[0008] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture, and then cold-press the mixture into shape and cure to obtain a preform;

[0009] (3) Pre-sinter the preform at 150 - 200 °C to obtain a sintered body;

[0010] (4) Cast the sintered body with a melt to obtain a steel matrix composite material.

[0011] Preferably, in the step (1), the metal powder comprises at least two of Ti, W, Cr, V, Mo, and Nb.

[0012] In the present invention, the initial powder is first pressed into spherical particles, then a binder is added to obtain a mixture, and then the mixture is prepared into a preform by cold pressing. Subsequently, the preform is pre-sintered to obtain a sintered body. Then, the sintered body is subjected to high-temperature melt casting. The sintered body will undergo a phase transformation reaction under the action of the high-temperature melt, and two or more hard particles such as TiC, WC, Cr x C y , VC, MoC, and NbC are self-generated, and finally a steel matrix composite material is obtained. The sintered body of the present invention not only has three-dimensional interconnected pores but also has a certain strength, which can effectively resist the erosion of the high-temperature melt and prevent the sintered body from collapsing.

[0013] If the pre-sintering temperature is too low, the strength of the sintered body will decrease, and finally there is a risk of being washed away in the steel matrix composite material. If the pre-sintering temperature is too high, the sintered body will undergo a phase transformation reaction. Therefore, by controlling the pre-sintering temperature within the above range, the present invention is beneficial to improving the performance of the steel matrix composite material.

[0014] Since spherical particles have a high specific surface area, after being prepared into a preform, the contact area between the metal matrix and the hard particles is increased, the pinning effect of the matrix on the hard particles is improved, and it is beneficial to obtain a high-quality composite material.

[0015] The TiC, WC, Cr x C y , VC, MoC, NbC and other two or more hard particles in the steel matrix composite material have a volume fraction greater than 60%.

[0016] It should be noted that the Cr x C y is a kind of carbide, and has different forms such as Cr 23 C6, Cr6C, Cr7C3, and Cr3C.

[0017] Preferably, in the step (1), in terms of atomic percentage, the initial powder comprises 50% of C, 20 - 45% of Ti, 0 - 25% of W, 0 - 10% of V, 0 - 5% of Nb, 0 - 20% of Cr, and 0 - 10% of Mo.

[0018] Preferably, in the step (2), the average particle size of the spherical particles is 3 - 5 mm.

[0019] If the particle size of the spherical particles is too small, the pores between the preforms will be too small, which is not conducive to subsequent melt infiltration. If the particle size of the spherical particles is too large, the volume fraction of the hard phase in the composite structure will be low, which is not conducive to the overall improvement of performance. Therefore, by controlling the particle size of the spherical particles within the above range in the present invention, it is beneficial to improve the performance of the steel matrix composite material.

[0020] More preferably, the average particle size of the spherical particles is any one of 3 mm, 3.5 mm, 4 mm, 4.5 mm, 5 mm or a range value between the two.

[0021] Preferably, in the step (2), the mass of the binder accounts for 2-5% of the mass of the spherical particles, and specifically can be any one of 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, 5% or a range value between the two.

[0022] The binder in the present invention can adopt a conventional organic resin binder.

[0023] Preferably, in the step (2), the pressure of the cold pressing is 20-30 MPa, and the pressure holding time is 10-20 s.

[0024] Preferably, in the step (3), the strength of the sintered compact is greater than 15 MPa.

[0025] Preferably, in the step (4), the casting temperature is 1350-1500 °C, and specifically can be any one of 1350 °C, 1380 °C, 1400 °C, 1420 °C, 1450 °C, 1480 °C, 1500 °C or a range value between the two.

[0026] Preferably, in the step (4), the melt can be high-chromium cast iron, high-manganese steel, alloy steel, etc.

[0027] In the second aspect, the present invention also provides a steel matrix composite material prepared by the above method.

[0028] Preferably, the steel matrix composite material includes hard particles, and the hard particles include at least two of TiC, WC, Cr x C y , VC, MoC, NbC.

[0029] In the third aspect, the present invention also provides an application of the steel matrix composite material in vulnerable parts, and specifically can be used for small and medium-sized thin-walled vulnerable parts such as impellers, pump casings, cutter teeth, drill bits, and shield machine hob cutters in the fields of dredging and tunneling, etc., which can significantly improve their service life.

[0030] Compared with the prior art, the beneficial effects of the present invention are:

[0031] In the present invention, the initial powder is pressed into spherical particles and then made into a sintered compact. The large specific surface area of the individual spherical particles in the sintered compact increases the contact area between the hard particles and the matrix, which is beneficial to the pinning effect of the matrix on the hard particles. Moreover, the presence of spherical particles can avoid violent phase transformation reactions during the later casting process of the sintered compact. Meanwhile, two or more hard particles such as TiC, WC, Cr x C y , VC, MoC, NbC, etc. are obtained through phase transformation reactions. These hard particles have good metallurgical bonding with the steel matrix, and finally a steel matrix composite material with stable microstructure and excellent properties is obtained. In addition, the preparation method of the present invention is simple in operation, high in production efficiency, can realize one-time forming of castings, and is suitable for low-cost mass production of steel matrix composite materials with stable microstructure and good properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic diagram of pressing the initial powder into spherical particles.

[0033] Figure 2 is the microstructure morphology of the steel matrix composite material of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0034] To better illustrate the purpose, technical solution and advantages of the present invention, the present invention will be further described below in conjunction with specific embodiments, but the protection scope and implementation manner of the present invention are not limited thereto.

[0035] The materials, reagents, etc. used in the following examples are commercially available reagents and materials without special instructions.

[0036] The binder used in the following examples and comparative examples is an organic resin binder, and the melt is an alloy steel liquid.

[0037] Example 1

[0038] A preparation method of a steel matrix composite material includes the following steps:

[0039] (1) Mix 50% of C, 30% of Ti, and 20% of W evenly according to atomic percentage to obtain the initial powder;

[0040] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture. The mass of the binder accounts for 5% of the mass of the spherical particles; subsequently, pour the mixture into a mold and cold press it into shape. The pressure for cold pressing is 20 MPa, and the pressure holding time is 20 s. After curing, a preform is obtained;

[0041] (3) Pre-sinter the preform at 180 °C for 30 min to obtain a sintered body. The sintered body has three-dimensional interconnected pores and has the ability to resist the erosion of high-temperature melt;

[0042] (4) Fix the sintered body at a specified position in the sand box, cast the sintered body with a melt at 1500 °C, and induce in-situ reaction of the sintered body with the high-temperature melt to make it fully react and generate multi-phase hard particles of TiC and WC, and finally obtain a steel matrix composite material.

[0043] The average hardness of the steel matrix composite material prepared in this example reaches 1730 HV, and its anti-wear ability during abrasive wear is more than 2.8 times higher than that of the matrix material.

[0044] Example 2

[0045] A preparation method of a steel matrix composite material, comprising the following steps:

[0046] (1) Mix 50% C, 40% Ti, and 10% V evenly by atomic percentage to obtain initial powder;

[0047] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture. The mass of the binder accounts for 5% of the mass of the spherical particles; subsequently, pour the mixture into a specific mold and cold press it into shape. The pressure for cold pressing is 20 MPa, and the pressure holding time is 20 s. After curing, a preform is obtained;

[0048] (3) Pre-sinter the preform at 150 °C for 30 min to obtain a sintered body. The sintered body has three-dimensional interconnected pores and has the ability to resist the erosion of high-temperature melt;

[0049] (4) Fix the sintered body at a specified position in the sand box, cast the sintered body with a melt at 1500 °C, and induce in-situ reaction of the sintered body with the high-temperature melt to make it fully react and generate multi-phase hard particles of TiC and VC, and finally obtain a steel matrix composite material.

[0050] The average hardness of the steel matrix composite material prepared in this example reaches 1700 HV, and its anti-wear ability during abrasive wear is more than 2.6 times higher than that of the matrix material.

[0051] Example 3

[0052] A preparation method of a steel matrix composite material, comprising the following steps:

[0053] (1) Mix 50% C, 45% Ti, and 5% Nb evenly by atomic percentage to obtain initial powder;

[0054] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture. The mass of the binder accounts for 5% of the mass of the spherical particles. Subsequently, pour the mixture into a specific mold and cold press it into shape. The pressure for cold pressing is 30 MPa, and the pressure holding time is 10 s. After curing, a preform is obtained.

[0055] (3) Pre-sinter the preform at 180 °C for 30 min to obtain a sintered body. The sintered body has three-dimensional interconnected pores and has the ability to resist the erosion of high-temperature melts.

[0056] (4) Fix the sintered body at a designated position in the sand box, cast the sintered body with a melt at 1500 °C, and induce an in-situ reaction of the sintered body with the high-temperature melt to make it react completely and generate TiC and NbC multiphase hard particles, and finally obtain a steel matrix composite material.

[0057] The average hardness of the steel matrix composite material prepared in this example reaches 1695 HV, and its anti-wear ability during abrasive wear is more than 2.7 times higher than that of the matrix material.

[0058] Example 4

[0059] A method for preparing a steel matrix composite material includes the following steps:

[0060] (1) Mix 50% C, 30% Ti, and 20% Cr evenly by atomic percentage to obtain the initial powder.

[0061] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture. The mass of the binder accounts for 4% of the mass of the spherical particles. Subsequently, pour the mixture into a specific mold and cold press it into shape. The pressure for cold pressing is 30 MPa, and the pressure holding time is 10 s. After curing, a preform is obtained.

[0062] (3) Pre-sinter the preform at 185 °C for 30 min to obtain a sintered body. The sintered body has three-dimensional interconnected pores and has the ability to resist the erosion of high-temperature melts.

[0063] (4) Fix the sintered body at a designated position in the sand box, cast the sintered body with a melt at 1500 °C, and induce an in-situ reaction of the sintered body with the high-temperature melt to make it react completely and generate TiC, Cr x C y multiphase hard particles, and finally obtain a steel matrix composite material.

[0064] The average hardness of the steel matrix composite material prepared in this example reaches 1720 HV, and its anti-wear ability during abrasive wear is more than 2.9 times higher than that of the matrix material.

[0065] Example 5

[0066] A method for preparing a steel-based composite material, comprising the following steps:

[0067] (1) Mix 50% C, 25% Ti, and 25% W evenly by atomic percentage to obtain an initial powder;

[0068] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture. The mass of the binder accounts for 3% of the mass of the spherical particles; subsequently, pour the mixture into a specific mold and cold press it into shape. The pressure for cold pressing is 30 MPa, and the pressure holding time is 10 s. After curing, a preform is obtained;

[0069] (3) Pre-sinter the preform at 200 °C for 30 min to obtain a sintered body. The sintered body has three-dimensional interconnected pores and has the ability to resist the erosion of high-temperature melts;

[0070] (4) Fix the sintered body at a specified position in a sand box, cast the sintered body with a melt at 1500 °C, and induce in-situ reactions in the sintered body using the high-temperature melt to make it fully react and generate TiC and WC multi-phase hard particles, finally obtaining a steel-based composite material.

[0071] The average hardness of the steel-based composite material prepared in this example reaches 1850 HV, and its anti-wear ability during abrasive wear is more than 3.2 times higher than that of the matrix material.

[0072] Example 6

[0073] A method for preparing a steel-based composite material, comprising the following steps:

[0074] (1) Mix 50% C, 40% Ti, and 10% Mo evenly by atomic percentage to obtain an initial powder;

[0075] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture. The mass of the binder accounts for 4% of the mass of the spherical particles; subsequently, pour the mixture into a specific mold and cold press it into shape. The pressure for cold pressing is 25 MPa, and the pressure holding time is 15 s. After curing, a preform is obtained;

[0076] (3) Pre-sinter the preform at 185 °C for 30 min to obtain a sintered body. The sintered body has three-dimensional interconnected pores and has the ability to resist the erosion of high-temperature melts;

[0077] (4) Fix the sintered compact to a specified position in the sand mold, cast the sintered compact with a melt at 1500 °C, and induce in-situ reactions of the sintered compact with the high-temperature melt to make it fully react and generate multi-phase hard particles of TiC and MoC, finally obtaining a steel matrix composite material.

[0078] The average hardness of the steel matrix composite material prepared in this example reaches 1750 HV, and its anti-wear ability during abrasive wear is increased by more than 3.0 times compared with the matrix material.

[0079] Example 7

[0080] A preparation method of a steel matrix composite material includes the following steps:

[0081] (1) Mix 50% C, 20% Ti, 15% W, and 15% Cr evenly by atomic percentage to obtain initial powder;

[0082] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture, and the mass of the binder accounts for 4% of the mass of the spherical particles; subsequently, pour the mixture into a specific mold for cold pressing, the pressure of cold pressing is 20 MPa, and the pressure holding time is 15 s, and a preform is obtained after curing;

[0083] (3) Pre-sinter the preform at 165 °C for 30 min to obtain a sintered compact, and the sintered compact has three-dimensional interconnected pores and the ability to resist erosion by high-temperature melt;

[0084] (4) Fix the sintered compact to a specified position in the sand mold, cast the sintered compact with a melt at 1500 °C, and induce in-situ reactions of the sintered compact with the high-temperature melt to make it fully react and generate TiC, WC, Cr x C y multi-phase hard particles, finally obtaining a steel matrix composite material.

[0085] The average hardness of the steel matrix composite material prepared in this example reaches 1780 HV, and its anti-wear ability during abrasive wear is increased by more than 3.2 times compared with the matrix material.

[0086] Example 8

[0087] A preparation method of a steel matrix composite material includes the following steps:

[0088] (1) Mix 50% C, 25% Ti, 20% W, and 5% V evenly by atomic percentage to obtain initial powder;

[0089] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture. The mass of the binder accounts for 4% of the mass of the spherical particles. Subsequently, pour the mixture into a specific mold for cold pressing. The pressure for cold pressing is 30 MPa, and the pressure holding time is 10 s. After curing, a preform is obtained.

[0090] (3) Pre-sinter the preform at 165 °C for 30 min to obtain a sintered body. The sintered body has three-dimensional interconnected pores and has the ability to resist the erosion of high-temperature melts.

[0091] (4) Fix the sintered body to a designated position in the sand box, cast the sintered body with a melt at 1500 °C, and induce in-situ reaction of the sintered body with the high-temperature melt to make it fully react and generate multi-phase hard particles of TiC, WC, and VC. Finally, a steel matrix composite material is obtained.

[0092] The average hardness of the steel matrix composite material prepared in this example reaches 1745 HV, and its anti-wear ability during abrasive wear is increased by more than 3.1 times compared with the matrix material.

[0093] Example 9

[0094] A method for preparing a steel matrix composite material includes the following steps:

[0095] (1) Mix 50% C, 25% Ti, 20% Cr, and 5% V evenly according to atomic percentages to obtain an initial powder.

[0096] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture. The mass of the binder accounts for 3% of the mass of the spherical particles. Subsequently, pour the mixture into a specific mold for cold pressing. The pressure for cold pressing is 25 MPa, and the pressure holding time is 10 s. After curing, a preform is obtained.

[0097] (3) Pre-sinter the preform at 150 °C for 30 min to obtain a sintered body. The sintered body has three-dimensional interconnected pores and has the ability to resist the erosion of high-temperature melts.

[0098] (4) Fix the sintered body to a designated position in the sand box, cast the sintered body with a melt at 1500 °C, and induce in-situ reaction of the sintered body with the high-temperature melt to make it fully react and generate TiC, Cr x C y , VC multi-phase hard particles, and finally a steel matrix composite material is obtained.

[0099] The average hardness of the steel matrix composite material prepared in this example reaches 1800 HV, and its anti-wear ability during abrasive wear is increased by more than 3.1 times compared with the matrix material.

[0100] Example 10

[0101] A method for preparing a steel-based composite material, comprising the following steps:

[0102] (1) Mix 50% C, 25% Ti, 20% Cr, and 5% Nb evenly by atomic percentage to obtain initial powder;

[0103] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture. The mass of the binder accounts for 3% of the mass of the spherical particles; subsequently, pour the mixture into a specific mold and cold press it into shape. The pressure for cold pressing is 20 MPa, and the pressure holding time is 10 s. After curing, a preform is obtained;

[0104] (3) Pre-sinter the preform at 150 °C for 30 min to obtain a sintered body. The sintered body has three-dimensional interconnected pores and has the ability to resist the erosion of high-temperature melt;

[0105] (4) Fix the sintered body at a specified position in a sand box, cast the sintered body with a melt at 1500 °C, and use the high-temperature melt to induce in-situ reaction of the sintered body to make it react completely and generate TiC, Cr x C y , NbC multi-phase hard particles, and finally obtain a steel-based composite material.

[0106] The average hardness of the steel-based composite material prepared in this example reaches 1795 HV, and its anti-wear ability during abrasive wear is more than 3.2 times higher than that of the matrix material.

[0107] Comparative Example 1

[0108] A method for preparing a steel-based composite material, comprising the following steps:

[0109] (1) Mix 50% C and 50% Ti evenly by atomic percentage to obtain initial powder;

[0110] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture. The mass of the binder accounts for 3% of the mass of the spherical particles; subsequently, pour the mixture into a specific mold and cold press it into shape. The pressure for cold pressing is 30 MPa, and the pressure holding time is 10 s. After curing, a preform is obtained;

[0111] (3) Pre-sinter the preform at 200 °C for 30 min to obtain a sintered body. The sintered body has three-dimensional interconnected pores and has the ability to resist the erosion of high-temperature melt;

[0112] (4) Fix the sintered blank to the designated position in the sand box, cast the sintered blank with a melt at 1500 °C, and use the high-temperature melt to induce in-situ reaction of the sintered blank to make it fully react and generate TiC multi-phase hard particles, and finally obtain a steel matrix composite material.

[0113] The average hardness of the steel matrix composite material prepared in this comparative example reaches 1300 HV, and its anti-wear ability during abrasive wear is more than doubled compared with the matrix material.

[0114] Comparative Example 2

[0115] A preparation method of a steel matrix composite material includes the following steps:

[0116] (1) Mix 50% C, 25% Ti, and 25% W evenly according to atomic percentage to obtain initial powder;

[0117] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture, and the mass of the binder accounts for 10% of the mass of the spherical particles; then pour the mixture into a specific mold and cold press it into shape, the cold pressing pressure is 30 MPa, and the pressure holding time is 10 s, and a preform is obtained after curing;

[0118] (3) Pre-sinter the preform at 200 °C for 30 min to obtain a sintered blank, the sintered blank has three-dimensional interconnected pores and has the ability to resist the erosion of high-temperature melt;

[0119] (4) Fix the sintered blank to the designated position in the sand box, cast the sintered blank with a melt at 1500 °C, and use the high-temperature melt to induce in-situ reaction of the sintered blank to make it fully react and generate TiC and WC multi-phase hard particles, and finally obtain a steel matrix composite material.

[0120] The average hardness of the steel matrix composite material prepared in this comparative example reaches 1320 HV, and its anti-wear ability during abrasive wear is more than 1.1 times higher than that of the matrix material.

[0121] Comparative Example 3

[0122] A preparation method of a steel matrix composite material includes the following steps:

[0123] (1) Mix 50% C, 25% Ti, and 25% W evenly according to atomic percentage to obtain initial powder;

[0124] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture. The mass of the binder accounts for 3% of the mass of the spherical particles. Subsequently, pour the mixture into a specific mold and perform cold pressing. The pressure for cold pressing is 30 MPa, and the pressure holding time is 10 s. After curing, a preform is obtained.

[0125] (3) Pre-sinter the preform at 100 °C for 30 min to obtain a sintered body. The sintered body has three-dimensional interconnected pores, but its own strength is relatively low.

[0126] (4) Fix the sintered body at a designated position in the sand box, cast the sintered body with a melt at 1500 °C, and utilize the high-temperature melt to induce an in-situ reaction of the sintered body, enabling it to fully react and generate TiC and WC multi-phase hard particles, and finally obtain a steel matrix composite material.

[0127] In the steel matrix composite material prepared in this comparative example, the sintered body in the structure has a phenomenon of being washed away. The average hardness in the hard particle enrichment area reaches 1650 HV, and the average hardness in the area with few hard particles is 1200 HV. During the abrasive wear process, the overall wear resistance of the steel matrix composite material is increased by more than 1 time compared with the matrix material.

[0128] Comparative Example 4

[0129] A method for preparing a steel matrix composite material includes the following steps:

[0130] (1) Mix 40% C, 30% Ti, and 30% Cr evenly according to atomic percentages to obtain an initial powder.

[0131] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture. The mass of the binder accounts for 3% of the mass of the spherical particles. Subsequently, pour the mixture into a specific mold and perform cold pressing. The pressure for cold pressing is 30 MPa, and the pressure holding time is 10 s. After curing, a preform is obtained.

[0132] (3) Pre-sinter the preform at 200 °C for 30 min to obtain a sintered body. The sintered body has three-dimensional interconnected pores and has the ability to resist the erosion of high-temperature melt.

[0133] (4) Fix the sintered body at a designated position in the sand box, cast the sintered body with a melt at 1500 °C, and utilize the high-temperature melt to induce an in-situ reaction of the sintered body, enabling it to fully react and generate TiC and WC multi-phase hard particles, and finally obtain a steel matrix composite material.

[0134] In the structure of the steel matrix composite material prepared in this comparative example, there are defects such as pores and incomplete C reaction. Its average hardness reaches 800 HV, and the overall abrasion resistance of the steel matrix composite material during abrasive wear is increased by more than 0.5 times compared with the matrix material.

[0135] Comparative Example 5

[0136] A preparation method of a steel matrix composite material includes the following steps:

[0137] (1) Mix 50% of C, 25% of Ti, and 25% of W evenly by atomic percentage to obtain initial powder;

[0138] (2) Press the initial powder into spherical particles, then add a binder and mix evenly to obtain a mixture. The mass of the binder accounts for 3% of the mass of the spherical particles; subsequently, pour the mixture into a specific mold and cold press it into shape. The pressure for cold pressing is 30 MPa, and the pressure holding time is 10 s. After curing, a preform is obtained;

[0139] (3) Pre-sinter the preform at 300 °C for 30 min to obtain a sintered body. The sintered body has three-dimensional interconnected pores, but its own strength is low. The Ti element in the sintered body undergoes an oxidation reaction;

[0140] (4) Fix the sintered body at a designated position in the sand box, cast the sintered body with a melt at 1500 °C, and use the high-temperature melt to induce in-situ reaction of the sintered body to make it react completely and generate TiC and WC multi-phase hard particles, and finally obtain a steel matrix composite material.

[0141] In the structure of the steel matrix composite material prepared in this comparative example, the presence of TiO2 particles is also detected. Its average hardness reaches 1320 HV, and its abrasion resistance during abrasive wear is increased by more than 0.6 times compared with the matrix material.

[0142] Comparative Example 6

[0143] A preparation method of a steel matrix composite material, which is different from Example 5 in that in step (2), the initial powder is not pressed into spherical particles.

[0144] In the structure of the steel matrix composite material prepared in this comparative example, there is a phenomenon of particle enrichment in the TiC, WC and other multi-phase hard particles generated. Its average hardness is 1000 - 1680 HV, and the overall abrasion resistance of the steel matrix composite material during abrasive wear is increased by more than 0.4 times compared with the matrix material.

[0145] Performance testing

[0146] 1. Average hardness: Tested with reference to GB / T 4340.1-2024 "Metallic materials - Vickers hardness test - Part 1: Test method".

[0147] 2. Wear performance: Tested with reference to YB / T 6177-2024 "Method for slurry erosion wear test of metallic materials".

[0148] The test results of the above-mentioned examples and comparative examples are shown in Table 1.

[0149] Table 1

[0150]

[0151]

[0152] It can be seen from Table 1 that the steel matrix composite material prepared by the powder metallurgy and casting processes of the present invention not only has a high hardness but also excellent wear resistance.

[0153] Finally, it should be noted that the above examples are only used to illustrate the technical solutions of the present invention and not to limit the protection scope of the present invention. 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 the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for preparing a steel-based composite material, characterized in that: The following steps are involved: (1) mixing carbon powder and metal powder in an atomic ratio of 1:1 to obtain an initial powder; (2) pressing the initial powder into spherical particles, then adding a binder and mixing evenly to obtain a mixture, and then cold-pressing the mixture to obtain a preform after curing; (3) pre-sintering the preform at 150-200° C. to obtain a sintered body; (4) Casting the sintered green body with a melt to obtain a steel-based composite material.

2. The method for preparing the steel-based composite material according to claim 1, characterized in that: In the step (1), the metal powder includes at least two of Ti, W, Cr, V, Mo, and Nb.

3. The method for preparing the steel-based composite material according to claim 2, characterized in that: In the step (1), the initial powder comprises 50% C, 20-45% Ti, 0-25% W, 0-10% V, 0-5% Nb, 0-20% Cr, and 0-10% Mo in terms of atomic percentage.

4. The method for preparing the steel-based composite material according to claim 1, characterized in that: In the step (2), the average particle size of the spherical particles is 3-5 mm.

5. The method for preparing the steel-based composite material according to claim 1, characterized in that: In the step (2), the mass of the binder accounts for 2-5% of the mass of the spherical particles.

6. The method for preparing the steel-based composite material according to claim 1, characterized in that: In the step (2), the cold pressing pressure is 20-30 MPa, and the holding time is 10-20 s.

7. The method for preparing the steel-based composite material according to claim 1, characterized in that: In the step (4), the casting temperature is 1350-1500°C.

8. The steel-based composite material prepared by the method for preparing a steel-based composite material according to any one of claims 1 to 7.

9. The steel-based composite material according to claim 8, characterized in that: The steel-based composite material includes hard particles, and the hard particles include TiC, WC, Cr x C y , VC, MoC, NbC, at least two of them.

10. Use of the steel-based composite material according to claim 9 in vulnerable parts.

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