An iron-based binder phase type ceramic matrix composite powder, a preparation method and application thereof

Abstract

The application belongs to the technical field of powder metallurgy and laser surface strengthening, and particularly discloses an iron-based binder phase type ceramic matrix composite powder, a preparation method and application thereof, the composite powder comprising an iron-based alloy powder, 8.45-9.77% W-Ta-Ti-C powder and 55.42-56.35% Ti(C,N) powder. The two kinds of ceramic powders are respectively sintered, cooled and sieved in a carbon tube furnace to obtain two kinds of ceramic powders, which are then mechanically mixed with the iron-based alloy powder. The obtained composite powder is single-strip oscillation cladded on a mining pick tooth base material, and two-stage vacuum heat treatment and tungsten steel head brazing are performed, so that the obtained cladding layer reaches a hardness level of 70HRC and is free of cracks, and the wear resistance and service life of the mining pick tooth are improved.

Description

Technical Field

[0001] This invention belongs to the field of powder metallurgy and laser surface strengthening technology, and specifically relates to an iron-based binder phase ceramic matrix composite powder, its preparation method and application. Background Technology

[0002] Cutting picks are primarily mounted on the rotary table of mining tunneling machines or shield tunneling machines. Driven by the rotary table, they collide with the ore body to separate the ore from the ore. During service, the cutting picks are subjected not only to significant friction but also to impact loads generated by ore collisions. A cutting pick typically consists of two parts: a tungsten carbide head and an iron substrate, connected by copper brazing to reduce the risk of the tungsten carbide head detaching under harsh working conditions. During mining, the cutting pick substrate, near the tungsten carbide head, is also subjected to collisions and wear from the ore, leading to rapid wear. To improve the wear resistance of the cutting picks, current technology typically employs surface strengthening of the cutting pick substrate by overlaying high-hardness wear-resistant alloys.

[0003] Currently, commonly used alloy materials for weld overlay cutting tools include iron-based high-carbon high-chromium alloys, steel-bonded cemented carbides, and nickel-based carbide alloys. Corresponding welding techniques include arc welding and plasma welding. Due to the small size of the cutting tools, the heat input in traditional welding processes can easily cause the tool substrate to heat up rapidly, generating significant internal stress in the high-hardness weld overlay layer, thus increasing the likelihood of cracking. Simultaneously, high heat input and workpiece temperature rise can also cause the decomposition of the hard phase in the weld overlay layer, affecting its hardness and wear resistance. To reduce heat input and minimize hard phase decomposition, laser cladding has been used for surface strengthening of the cutting tool substrate.

[0004] For example, Chinese patent CN116037957A discloses a method for laser cladding additive manufacturing of cutting tools. This method uses an Fe / Ni-based alloy material as the binder phase and ceramic powder, comprising no less than 50% by mass, as the hard phase. The ceramic powder can be WC alloy powder. The hardness, wear resistance, and impact resistance of the laser cladding layer are typically determined by both the binder and hard phases. Therefore, the composition of the binder phase, the type of hard phase, and their ratio all affect the overall performance of the cladding layer. For mining cutting tools that simultaneously withstand friction and impact loads, further coordination of the relationship between the hardness, toughness, and crack resistance of the cladding layer is still necessary.

[0005] Chinese patent CN107338438A discloses a wear-resistant laser cladding layer for a hobbing cutter ring and its preparation method. It uses Ni-based WC alloy powder, with the WC hard phase comprising 30%–60% by mass. This type of nickel-based carbide cladding material can improve the wear resistance of the working surface, but its material system differs from the substrate of mining cutting tools and its combined impact and friction conditions. In strengthening the surface of mining cutting tools, it is still necessary to consider factors such as the bonding between the cladding material and the substrate, the hardness and toughness of the cladding layer, crack control, and material cost. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects in the prior art and provide an iron-based binder phase ceramic matrix composite powder, its preparation method, and a laser cladding method for strengthening mining cutters.

[0007] In a first aspect, the present invention provides an iron-based binder phase type ceramic matrix composite powder, comprising iron-based alloy powder, W-Ta-Ti-C powder and Ti(C,N) powder; wherein the weight percentage of the W-Ta-Ti-C powder is 8.45 to 9.77%, the weight percentage of the Ti(C,N) powder is 55.42 to 56.35%, and the balance is the iron-based alloy powder; The iron-based alloy powder is composed of the following components by weight percentage: C: 0.37–0.39%, Cr: 4.69–5.45%, Co: 8.82–9.47%, Ni: 6.91–7.23%, Mo: 1.15–1.25%, Mn: 0.33–0.46%, Si: 0.52–0.71%, balance Fe.

[0008] A further embodiment is that the particle size of the W-Ta-Ti-C powder and the Ti(C,N) powder is 28-45 μm, and the particle size of the iron-based alloy powder is 53-150 μm.

[0009] A further embodiment is that the W-Ta-Ti-C powder is composed of the following components by weight percentage: Ta: 19.25-19.50%, Ti: 14.66-15.31%, C: 8.38-8.74%, with the balance being W.

[0010] A further embodiment is that the Ti(C,N) powder is composed of the following components by weight percentage: C: 10.70-11.46%, N: 8.14-8.73%, with the balance being Ti.

[0011] A second aspect of the present invention provides a method for preparing iron-based binder phase ceramic matrix composite powder, comprising the following steps: Iron-based alloy powder was prepared according to the following weight percentages: C: 0.37–0.39%, Cr: 4.69–5.45%, Co: 8.82–9.47%, Ni: 6.91–7.23%, Mo: 1.15–1.25%, Mn: 0.33–0.46%, Si: 0.52–0.71%, with the balance being Fe. W-Ta-Ti-C powder and Ti(C,N) powder were prepared using separate powder preparation methods. Based on the total weight of the iron-based binder ceramic matrix composite powder, the iron-based binder ceramic matrix composite powder is obtained by mechanically mixing W-Ta-Ti-C powder (8.45-9.77%), Ti(C,N) powder (55.42-56.35%), and the balance iron-based alloy powder.

[0012] A further embodiment is that the preparation process of the W-Ta-Ti-C powder includes the following steps: S11. To achieve the target composition of the obtained W-Ta-Ti-C powder, weigh out elemental tungsten powder, tantalum oxide powder, titanium dioxide and carbon black, mix them thoroughly and press them into a boat. S12. Place the mixture after pressing into a boat in a carbon tube furnace, sinter at 1190±10℃ and hold for 2 hours, then heat to 1720±10℃ at a heating rate of 30±2℃ / min and hold for 2.5 hours. S13. After the heat preservation is completed, the sintered product is cooled to room temperature with the furnace. The cooled sintered product is then sieved and classified to obtain W-Ta-Ti-C powder.

[0013] A further embodiment is that the preparation process of the Ti(C,N) powder includes the following steps: S21. To obtain Ti(C,N) powder with the target composition of C: 10.70-11.46%, N: 8.14-8.73%, and the balance being Ti, weigh out the first titanium dioxide, the first carbon black, the second titanium dioxide, and the second carbon black respectively; thoroughly mix the first titanium dioxide and the first carbon black and press them into a boat; place the mixture after pressing into the boat in a carbon tube furnace at 2300±20℃ for sintering to obtain TiC; S22. Thoroughly mix the TiC, the second titanium dioxide, and the second carbon black and press them into a boat. Place the mixture after pressing into a boat into a carbon tube furnace through which N2 is introduced, and reduce and nitrid at 1800±20℃ and keep it at that temperature for 4 hours. S23. After sintering, the sintered product is cooled to room temperature with the furnace. The cooled sintered product is then sieved and classified to obtain Ti(C,N) powder.

[0014] A third aspect of the present invention provides a laser cladding method for strengthening mining cutters, using the aforementioned iron-based binder phase ceramic matrix composite powder, comprising the following steps: Using the iron-based binder phase ceramic matrix composite powder as the cladding material, a single-strip oscillating cladding is performed on the mining cutter substrate to form a laser cladding layer; The laser-clad mining cutter is placed in a vacuum furnace for vacuum heat treatment, and then removed from the furnace and air-cooled after the vacuum heat treatment is completed. Brazing is performed on the tungsten carbide head of the air-cooled mining cutter.

[0015] A further proposed solution is that, in step S1, the parameter setting process for single-strip oscillating cladding is as follows: a fiber laser with a spot diameter of 4mm is used, the laser power is 2500-2700W, the cladding thickness on one side is 2.8-3.2mm, the rotational linear speed of the mining cutting teeth is 1.4-1.6mm / s, the linear speed of the laser head oscillating left and right is 20-22mm / s, and the oscillation width of the laser head is 21-23mm.

[0016] A further embodiment is that the vacuum heat treatment in step S2 includes: heating to 580±10℃ at a heating rate of 20.2~22.4℃ / min and holding for 7±2min; then heating to 915±10℃ at a heating rate of 27.5~29.5℃ / min and holding for 5±1min.

[0017] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention employs a specific composition of iron-based alloy powder as the binder phase, and W-Ta-Ti-C powder and Ti(C,N) powder as the ceramic hard phase. C, Cr, Co, Ni, and Mo in the iron-based binder phase are used to coordinate the hardness and toughness of the binder phase, while Mn and Si are beneficial for desulfurization, deoxidation, and cladding layer formation. The W-Ta-Ti-C powder and Ti(C,N) powder, while improving the hardness and wear resistance of the cladding layer, help reduce the decomposition of the ceramic hard phase during laser cladding and subsequent heat treatment, thus achieving a balance between high hardness, impact resistance, and crack resistance in the cladding layer.

[0018] This invention involves sintering, cooling, sieving, and classifying W-Ta-Ti-C powder and Ti(C,N) powder separately, then mechanically mixing them with iron-based alloy powder. By limiting the particle size and weight percentage of each powder, the ceramic hard phase is uniformly distributed within the iron-based binder phase. Combined with low-heat-input single-strand oscillating laser cladding and two-stage vacuum heat treatment, the residual stress and cracking tendency of the cladding layer can be reduced, and the toughness and subsequent brazing adaptability of the cladding layer can be improved.

[0019] The cladding layer of mining cutting tools prepared using the composite powder and laser cladding method of this invention can reach a hardness level of 70 HRC, and no cracks were found after penetrant testing. Trial results show that the service life of the strengthened mining cutting tools can reach 2.2 to 2.6 times that of conventional welded cutting tools. At the same time, the iron-based binder helps to reduce the cost of the cladding material and improve its compatibility with the cutting tool substrate. Attached Figure Description

[0020] The following figures are for illustrative purposes only and are not intended to limit the scope of the invention, wherein: Figure 1 Real photos of mining cutting tools; Figure 2 According to the composition of the iron-based binder phase provided in Example 3 of the present invention, the hardness phase transformation diagram was calculated; in the diagram: Martensite start is the temperature at which the martensitic phase transformation begins; Martensite 50% is the temperature at which 50% of the martensitic phase transformation is completed; Martensite 90% is the temperature at which 90% of the martensitic phase transformation is completed; Figure 3 : A real-life photograph of penetrant testing performed on laser-clad cutting teeth according to the solution provided in Embodiment 3 of the present invention; Figure 4 Metallographic photograph of the microstructure of the cladding layer according to the solution provided in Embodiment 3 of the present invention; In the diagram: 1. Cutting tooth base; 2. Cladding position; 3. Brazing position; 4. Tungsten carbide head. Detailed Implementation

[0021] To make the objectives, technical solutions, design methods, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the invention.

[0022] In this invention, all percentages are weight percentages. The percentage content of each element in the iron-based alloy powder is based on the total weight of the iron-based alloy powder itself; the amount of W-Ta-Ti-C powder and Ti(C,N) powder added is based on the total weight of the final composite powder; the elemental percentage content of W-Ta-Ti-C powder and Ti(C,N) powder is based on the total weight of the corresponding powder. Ti(C,N) represents titanium carbonitride.

[0023] Example 1 This embodiment provides an iron-based binder phase type ceramic matrix composite powder. The iron-based alloy powder is composed of C 0.38%, Cr 4.69%, Co 8.82%, Ni 6.91%, Mo 1.15%, Mn 0.33%, Si 0.52%, and the balance Fe by weight percentage. Based on the total weight of the final composite powder, W-Ta-Ti-C powder accounts for 8.45%, Ti(C,N) powder 55.42%, and iron-based alloy powder 36.13%. The W-Ta-Ti-C powder is composed of Ta 19.25%, Ti 14.66%, C 8.38%, and the balance W by weight percentage; the Ti(C,N) powder is composed of C 10.70%, N 8.14%, and the balance Ti by weight percentage. The particle size of both the W-Ta-Ti-C powder and the Ti(C,N) powder is 28–45 μm, and the particle size of the iron-based alloy powder is 53–150 μm.

[0024] This embodiment uses the lower limit values ​​of two ceramic hard phase content ranges to control the cracking tendency of the cladding layer while ensuring hardness; Fe is used as the balance element, which helps to reduce material costs and improve the compatibility of composite powder with cutting tool substrate.

[0025] This embodiment also provides a method for preparing the above-mentioned composite powder. Iron-based alloy powder is prepared according to the above-mentioned iron-based alloy powder composition and sieved to a particle size of 53–150 μm. To achieve the target composition of the obtained W-Ta-Ti-C powder satisfying Ta 19.25%, Ti 14.66%, C 8.38%, and the balance W, elemental tungsten powder, tantalum oxide powder, titanium dioxide, and carbon black are weighed, thoroughly mixed, and pressed into a boat. The mixture is placed in a carbon tube furnace and sintered at 1190±10℃ for 2 hours. Then, the temperature is increased to 1720±10℃ at a heating rate of 30±2℃ / min and held for 2.5 hours. After the holding period, the sintered product is cooled to room temperature with the furnace. The cooled sintered product is sieved and graded to obtain W-Ta-Ti-C powder with a particle size of 28–45 μm.

[0026] To achieve the target composition of Ti(C,N) powder with C 10.70%, N 8.14%, and the balance Ti, first titanium dioxide, first carbon black, second titanium dioxide, and second carbon black were weighed out respectively. The first titanium dioxide and first carbon black were thoroughly mixed and pressed into a boat. The mixture after pressing was placed in a carbon tube furnace at 2300±20℃ for sintering to obtain TiC. The obtained TiC, second titanium dioxide, and second carbon black were thoroughly mixed and pressed into a boat. The mixture after pressing was placed in a carbon tube furnace with N2 introduced, and reduced and nitrided at 1800±20℃ for 4 hours. After sintering, the sintered product was cooled to room temperature with the furnace. The cooled sintered product was sieved and graded to obtain Ti(C,N) powder with a particle size of 28-45 μm. Based on the total weight of the final composite powder, 8.45% of W-Ta-Ti-C powder, 55.42% of Ti(C,N) powder and 36.13% of iron-based alloy powder were thoroughly mechanically mixed to obtain iron-based binder phase ceramic matrix composite powder.

[0027] This embodiment also provides a laser cladding method for reinforcing mining cutters with the aforementioned composite powder. For example... Figure 1 As shown, the mining cutting tool includes a cutting tool base 1 and a tungsten carbide head 4. The concave surface of the cutting tool base 1 forms a cladding position 2, and the convex surface of the cutting tool base 1 forms a brazing position 3. During laser cladding, a laser cladding layer is formed at the cladding position 2 of the cutting tool base 1. After vacuum heat treatment and air cooling after exiting the furnace, the tungsten carbide head 4 is brazed at the brazing position 3. A fiber laser with a spot diameter of 4 mm is used, and the composite powder is used as the cladding material for oscillating cladding on the mining cutting tool base material. The laser power is 2500 W, the cladding thickness on one side is 2.8 mm, the rotational linear velocity of the mining cutting tool is 1.4 mm / s, the linear velocity of the laser head oscillating left and right is 20 mm / s, and the oscillation width is 21 mm. After laser cladding, the mining cutter is placed in a vacuum furnace and heated to 580°C at a heating rate of 20.2°C / min and held for 5 min. Then it is heated to 905°C at a heating rate of 27.5°C / min and held for 4 min. After vacuum heat treatment, the cutter is removed from the furnace and air-cooled. The tungsten steel head of the mining cutter is then brazed.

[0028] The first stage of vacuum heating was used to reduce the cracking tendency of the cladding layer during the heating process; the second stage of vacuum heating was used to improve the toughness of the cladding layer and the impact resistance of the mining cutter, and to provide a suitable microstructure for brazing the tungsten carbide head. No cracks were found in the resulting cladding layer after penetrant testing, and the hardness test value was 87.4 HRA, reaching the 70 HRC hardness level.

[0029] Example 2 This embodiment provides an iron-based binder phase type ceramic matrix composite powder. The iron-based alloy powder consists of C 0.39%, Cr 5.45%, Co 9.47%, Ni 7.23%, Mo 1.25%, Mn 0.46%, Si 0.71%, and the balance Fe by weight percentage. Based on the total weight of the final composite powder, W-Ta-Ti-C powder accounts for 9.77%, Ti(C,N) powder accounts for 56.35%, and iron-based alloy powder accounts for 33.88%. The W-Ta-Ti-C powder consists of Ta 19.50%, Ti 15.31%, C 8.74%, and the balance W by weight percentage; the Ti(C,N) powder consists of C 11.46%, N 8.73%, and the balance Ti by weight percentage. The particle size of both the W-Ta-Ti-C powder and the Ti(C,N) powder is 28–45 μm, and the particle size of the iron-based alloy powder is 53–150 μm.

[0030] This embodiment uses the upper limit of the content range of each component to verify the hardness and crack resistance of the cladding layer under conditions of high ceramic hard phase content. The W-Ta-Ti-C powder is controlled to be no higher than 9.77%, and the Ti(C,N) powder is controlled to be no higher than 56.35% to reduce the microstructure deterioration and cracking tendency caused by excessive hard phase. Fe is used as the balance element to reduce material cost and improve the bonding compatibility with the cutting tool substrate.

[0031] This embodiment also provides a method for preparing the above-mentioned composite powder. Iron-based alloy powder is prepared according to the above-mentioned iron-based alloy powder composition and sieved to a particle size of 53–150 μm. To achieve the target composition of the obtained W-Ta-Ti-C powder satisfying Ta 19.50%, Ti 15.31%, C 8.74%, and the balance W, elemental tungsten powder, tantalum oxide powder, titanium dioxide, and carbon black are weighed, thoroughly mixed, and pressed into a boat. The mixture is placed in a carbon tube furnace and sintered at 1190±10℃ for 2 hours. Then, the temperature is increased to 1720±10℃ at a heating rate of 30±2℃ / min and held for 2.5 hours. After the holding period, the sintered product is cooled to room temperature with the furnace. The cooled sintered product is sieved and graded to obtain W-Ta-Ti-C powder with a particle size of 28–45 μm.

[0032] To achieve the target composition of Ti(C,N) powder with C 11.46%, N 8.73%, and the balance Ti, first titanium dioxide, first carbon black, second titanium dioxide, and second carbon black were weighed out respectively. The first titanium dioxide and first carbon black were thoroughly mixed and pressed into a boat. The mixture after pressing was placed in a carbon tube furnace at 2300±20℃ for sintering to obtain TiC. The obtained TiC, second titanium dioxide, and second carbon black were thoroughly mixed and pressed into a boat. The mixture after pressing was placed in a carbon tube furnace with N2 introduced, and reduced and nitrided at 1800±20℃ for 4 hours. After sintering, the sintered product was cooled to room temperature with the furnace. The cooled sintered product was sieved and graded to obtain Ti(C,N) powder with a particle size of 28-45 μm. Based on the total weight of the final composite powder, 9.77% of W-Ta-Ti-C powder, 56.35% of Ti(C,N) powder and 33.88% of iron-based alloy powder were thoroughly mechanically mixed to obtain iron-based binder phase ceramic matrix composite powder.

[0033] This embodiment also provides a laser cladding method for reinforcing mining cutters with the aforementioned composite powder. The mining cutter in this embodiment is the same as in Embodiment 1. A fiber laser with a spot diameter of 4 mm is used, and the composite powder is used as the cladding material for single-strip oscillating cladding on the mining cutter substrate. The laser power is 2700 W, the cladding thickness on one side is 3.2 mm, the rotational linear velocity of the mining cutter is 1.6 mm / s, the left-right oscillation linear velocity of the laser head is 22 mm / s, and the oscillation width is 23 mm. After laser cladding, the mining cutter is placed in a vacuum furnace and heated to 590°C at a heating rate of 22.4°C / min and held for 9 min, then heated to 925°C at a heating rate of 29.5°C / min and held for 6 min. After vacuum heat treatment, the cutter is removed from the furnace and air-cooled, and the tungsten carbide head of the mining cutter is brazed.

[0034] The first stage of vacuum heating was used to reduce the cracking tendency of the cladding layer during the heating process; the second stage of vacuum heating was used to improve the toughness of the cladding layer and the impact resistance of the mining cutter, and to provide a suitable microstructure for brazing the tungsten carbide head. No cracks were found in the resulting cladding layer after penetrant testing, and the hardness test value was 87.6 HRA, reaching a hardness level of 70 HRC.

[0035] Example 3 This embodiment provides an iron-based binder phase type ceramic matrix composite powder. The iron-based alloy powder consists of 0.38% C, 5.07% Cr, 9.15% Co, 7.07% Ni, 1.20% Mo, 0.39% Mn, 0.62% Si, and the balance Fe by weight percentage. Based on the total weight of the final composite powder, the W-Ta-Ti-C powder is 9.11%, the Ti(C,N) powder is 55.89%, and the iron-based alloy powder is 35.00%. The W-Ta-Ti-C powder consists of 19.38% Ta, 14.99% Ti, 8.56% C, and the balance W by weight percentage; the Ti(C,N) powder consists of 11.08% C, 8.43% N, and the balance Ti by weight percentage. The particle size of both the W-Ta-Ti-C powder and the Ti(C,N) powder is 28–45 μm, and the particle size of the iron-based alloy powder is 53–150 μm.

[0036] This embodiment uses the middle value of the content range of each component to coordinate the hardness, toughness and crack resistance of the cladding layer; Fe is used as the balance element to reduce material cost and improve the compatibility of the composite powder with the cutting tool substrate.

[0037] This embodiment also provides a method for preparing the above-mentioned composite powder. Iron-based alloy powder is prepared according to the above-mentioned iron-based alloy powder composition and sieved to a particle size of 53–150 μm. To achieve the target composition of the obtained W-Ta-Ti-C powder satisfying Ta 19.38%, Ti 14.99%, C 8.56%, and the balance W, elemental tungsten powder, tantalum oxide powder, titanium dioxide, and carbon black are weighed, thoroughly mixed, and pressed into a boat. The mixture is placed in a carbon tube furnace and sintered at 1190±10℃ for 2 hours, then heated to 1720±10℃ at a heating rate of 30±2℃ / min and held for 2.5 hours. After the holding period, the sintered product is cooled to room temperature with the furnace. The cooled sintered product is then sieved and graded to obtain W-Ta-Ti-C powder with a particle size of 28–45 μm.

[0038] To achieve the target composition of Ti(C,N) powder with C 11.08%, N 8.43%, and the balance Ti, first titanium dioxide, first carbon black, second titanium dioxide, and second carbon black were weighed out respectively. The first titanium dioxide and first carbon black were thoroughly mixed and pressed into a boat. The mixture after pressing was placed in a carbon tube furnace at 2300±20℃ for sintering to obtain TiC. The obtained TiC, second titanium dioxide, and second carbon black were thoroughly mixed and pressed into a boat. The mixture after pressing was placed in a carbon tube furnace with N2 introduced, and reduced and nitrided at 1800±20℃ for 4 hours. After sintering, the sintered product was cooled to room temperature with the furnace. The cooled sintered product was sieved and graded to obtain Ti(C,N) powder with a particle size of 28-45 μm. Based on the total weight of the final composite powder, 9.11% of W-Ta-Ti-C powder, 55.89% of Ti(C,N) powder and 35.00% of iron-based alloy powder were thoroughly mechanically mixed to obtain iron-based binder phase ceramic matrix composite powder.

[0039] This embodiment also provides a laser cladding method for reinforcing mining cutters with the aforementioned composite powder. The mining cutter in this embodiment is the same as in Embodiment 1. A fiber laser with a spot diameter of 4 mm is used, and the composite powder is used as the cladding material for single-strip oscillating cladding on the mining cutter substrate. The laser power is 2600 W, the cladding thickness on one side is 3.0 mm, the rotational linear velocity of the mining cutter is 1.5 mm / s, the left-right oscillation linear velocity of the laser head is 21 mm / s, and the oscillation width is 22 mm. After laser cladding, the mining cutter is placed in a vacuum furnace and heated to 580°C at a heating rate of 21.3°C / min and held for 7 min, then heated to 915°C at a heating rate of 28.5°C / min and held for 5 min. After vacuum heat treatment, the cutter is removed from the furnace and air-cooled, and the tungsten carbide head of the mining cutter is brazed.

[0040] The first stage of vacuum heating is used to reduce the cracking tendency of the cladding layer during the heating process; the second stage of vacuum heating is used to improve the toughness of the cladding layer and the impact resistance of the mining cutter, and to provide a suitable microstructure for brazing the tungsten carbide head. The hardness of the iron-based binder phase obtained in Example 3 was tested using an SW-6210 Leeb hardness tester. A D-type impact device was used, and the tested materials were set as steel and cast steel. Eight consecutive impacts were performed. The instrument displayed a single hardness value of 59.0 HRC and an average hardness value of 59.3 HRC. The continuous cooling transformation curve was calculated based on the composition of the iron-based alloy powder in Example 3, and the results are as follows: Figure 2As shown, the Acm temperature of this iron-based binder phase is approximately 907.3℃, and the Al temperature is approximately 742.5℃. With decreasing temperature, martensitic transformation begins at approximately 220℃, reaching approximately 50% and 90% martensitic transformation amounts upon further cooling. Under the different cooling conditions shown in the figure, the calculated hardness is approximately 58 HRC, indicating that the selected iron-based binder phase composition can form a binder phase with martensite as the main strengthening structure over a wide range of cooling rates. No cracks were found in the obtained cladding layer after penetrant testing; the testing results are as follows. Figure 3 As shown. The hardness of the cladding layer was tested using a digital Rockwell hardness tester with a diamond cone indenter. The total test force was set to 60.00 kgf, and the test was conducted according to the HRA scale. The effective hardness values ​​displayed on the test interface were 89.5 HRA and 88.1 HRA, with a maximum value of 89.5 HRA, a minimum value of 88.1 HRA, and an average value of 88.8 HRA. The representative test value was 88.1 HRA. Because the cladding layer contains a high proportion of ceramic hard phase, its hardness exceeds the suitable testing range of the ordinary HRC scale; therefore, the HRA scale was used for characterization. The above test results show that the cladding layer reaches a hardness level of 70 HRC. Special note: Due to the presence of a large amount of hard phase and some binder phase in the cladding layer, most hardness values ​​tested with a Rockwell C hardness tester exceeded the Rockwell C limit of -70 HRC. This caused the hardness tester to fail to display the value; therefore, 88.1 HRA was used to represent the hardness of the cladding layer, which is equivalent to a hardness level of 70 HRC. Vacuum heat treatment process after laser cladding, such as Figure 4 As shown.

[0041] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles of the embodiments, their practical application, or technical improvements in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A type of iron-based binder phase ceramic matrix composite powder, characterized in that, It includes iron-based alloy powder, W-Ta-Ti-C powder and Ti(C,N) powder; the weight percentage of the W-Ta-Ti-C powder is 8.45-9.77%, the weight percentage of the Ti(C,N) powder is 55.42-56.35%, and the balance is the iron-based alloy powder.

2. The iron-based binder phase type ceramic matrix composite powder according to claim 1, characterized in that, The particle size of the W-Ta-Ti-C powder and the Ti(C,N) powder is 28-45 μm, and the particle size of the iron-based alloy powder is 53-150 μm. Preferably, the iron-based alloy powder is composed of the following components by weight percentage: C: 0.37–0.39%, Cr: 4.69–5.45%, Co: 8.82–9.47%, Ni: 6.91–7.23%, Mo: 1.15–1.25%, Mn: 0.33–0.46%, Si: 0.52–0.71%, balance Fe.

3. The iron-based binder phase type ceramic matrix composite powder according to claim 2, characterized in that, The W-Ta-Ti-C powder is composed of the following components by weight percentage: Ta: 19.25-19.50%, Ti: 14.66-15.31%, C: 8.38-8.74%, with the balance being W.

4. The iron-based binder phase type ceramic matrix composite powder according to claim 3, characterized in that, The Ti(C,N) powder is composed of the following components by weight percentage: C: 10.70-11.46%, N: 8.14-8.73%, with the balance being Ti.

5. A method for preparing iron-based binder phase type ceramic matrix composite powder, characterized in that, Includes the following steps: W-Ta-Ti-C powder, Ti(C,N) powder, and iron-based alloy powder were obtained respectively. Based on the total weight of the iron-based binder ceramic matrix composite powder, the iron-based binder ceramic matrix composite powder is obtained by mechanically mixing W-Ta-Ti-C powder (8.45-9.77%), Ti(C,N) powder (55.42-56.35%), and the balance iron-based alloy powder.

6. The method for preparing an iron-based binder phase ceramic matrix composite powder according to claim 5, characterized in that, The preparation process of the W-Ta-Ti-C powder includes the following steps: S11. To achieve the target composition of the obtained W-Ta-Ti-C powder, weigh out elemental tungsten powder, tantalum oxide powder, titanium dioxide and carbon black, mix them thoroughly and press them into a boat. S12. Place the mixture after pressing into a boat in a carbon tube furnace, sinter at 1190±10℃ and hold for 2 hours, then heat to 1720±10℃ at a heating rate of 30±2℃ / min and hold for 2.5 hours. S13. After the heat preservation is completed, the sintered product is cooled to room temperature with the furnace. The cooled sintered product is then sieved and classified to obtain W-Ta-Ti-C powder.

7. The method for preparing an iron-based binder phase ceramic matrix composite powder according to claim 5, characterized in that, The preparation process of the Ti(C,N) powder includes the following steps: S21. To obtain Ti(C,N) powder with the target composition of C: 10.70-11.46%, N: 8.14-8.73%, and the balance being Ti, weigh out the first titanium dioxide, the first carbon black, the second titanium dioxide, and the second carbon black respectively; thoroughly mix the first titanium dioxide and the first carbon black and press them into a boat; place the mixture after pressing into the boat in a carbon tube furnace at 2300±20℃ for sintering to obtain TiC; S22. Thoroughly mix the TiC, the second titanium dioxide, and the second carbon black and press them into a boat. Place the mixture after pressing into a boat into a carbon tube furnace through which N2 is introduced, and reduce and nitrid at 1800±20℃ and keep it at that temperature for 4 hours. S23. After sintering, the sintered product is cooled to room temperature with the furnace. The cooled sintered product is then sieved and classified to obtain Ti(C,N) powder.

8. A laser cladding method for strengthening mining cutters, characterized in that, The method of using the iron-based binder phase type ceramic matrix composite powder according to any one of claims 1 to 4 includes the following steps: Using the iron-based binder-phase ceramic matrix composite powder as the cladding material, a single-strip oscillating cladding is performed on the mining cutter substrate to form a laser cladding layer; The laser-clad mining cutter is placed in a vacuum furnace for vacuum heat treatment, and then removed from the furnace and air-cooled after the vacuum heat treatment is completed. Brazing is performed on the tungsten carbide head of the air-cooled mining cutting tool.

9. The laser cladding method for strengthening mining cutters according to claim 8, characterized in that, In step S1, the parameter setting process for single-strip oscillating cladding is as follows: a fiber laser with a spot diameter of 4mm is used, the laser power is 2500-2700W, the cladding thickness on one side is 2.8-3.2mm, the rotational linear speed of the mining cutting teeth is 1.4-1.6mm / s, the linear speed of the laser head oscillating left and right is 20-22mm / s, and the oscillation width of the laser head is 21-23mm.

10. A laser cladding method for strengthening mining cutters according to claim 9, characterized in that, The vacuum heat treatment in step S2 includes: heating to 580±10℃ at a heating rate of 20.2~22.4℃ / min and holding for 7±2min; then heating to 915±10℃ at a heating rate of 27.5~29.5℃ / min and holding for 5±1min.

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