A ternary boride Mo2NiB2 cermet and a preparation method thereof, and an alloy cartridge and a preparation method thereof

Abstract

This invention belongs to the field of laser additive manufacturing and surface engineering technology, and discloses a ternary boride Mo2NiB2 cermet and its preparation method, as well as an alloy barrel and its preparation method. The ternary boride Mo2NiB2 powder of this invention generates a stable, uniformly dispersed, high-hardness ternary boride hard phase in situ during the cladding process, endowing the alloy layer with excellent resistance to abrasive wear and corrosion. Simultaneously, a collaborative technical equipment system is formed by combining specialized internal hole laser cladding equipment, specially prepared ternary boride Mo2NiB2 cermet powder, and an optimized process integrating synchronous preheating, to overcome the technical bottleneck of internal wall cladding and ensure the acquisition of a dense, firmly bonded, and uniformly performing reinforced layer.

Description

Technical Field

[0001] This invention relates to the fields of laser additive manufacturing and surface engineering technology, and in particular to a ternary boride Mo2NiB2 cermet and its preparation method, and an alloy barrel and its preparation method. Background Technology

[0002] In the field of engineering plastics processing, core feeding components, such as the barrels and screws of extruders and injection molding machines, have their inner surfaces subjected to extremely harsh operating conditions for extended periods. These surfaces not only continuously endure high temperatures, high pressures, and high shear forces, but are also subjected to severe erosion and chemical corrosion from hard fillers (such as glass fibers, mineral powders, and flame retardants) in the plastic melt. Under these conditions, the performance of traditional materials (such as nitrided steel and conventional bimetallic bushings) is no longer sufficient to meet the requirements for long-term service, and they are prone to problems such as loss of equipment precision, increased energy consumption, and product contamination due to wear.

[0003] To improve barrel life, laser cladding technology has been applied as an advanced surface strengthening method. However, currently used laser cladding materials still have significant limitations when dealing with the aforementioned extreme working conditions: Traditional iron-based / nickel-based / cobalt-based alloys each have their own strengths in terms of wear resistance and corrosion resistance. Although they can improve the wear resistance of the matrix, their hardness is usually HRC<58, and their ability to resist abrasive wear is slightly insufficient. At the same time, they are difficult to have both excellent wear resistance and corrosion resistance, and they are difficult to effectively resist the long-term wear and erosion of highly filled engineering plastics.

[0004] Tungsten carbide (WC) reinforced composites: While adding tungsten carbide (WC) reinforcing phase to the three traditional alloys can significantly improve hardness and wear resistance, it has inherent disadvantages in practical applications: (a) It is easy to dissolve and undergo interfacial reactions in iron-based molten pools, forming brittle phases and impairing coating toughness; (b) It may have adverse chemical corrosion effects with certain halogenated flame retardants or their high-temperature decomposition products in engineering plastics, reducing the corrosion resistance of the alloy reinforced layer; (c) Tungsten resources are scarce and the material cost is high.

[0005] In contrast, ternary boride cermets (such as Mo2FeB2 and Mo2NiB2) exhibit significant advantages: they possess high hardness, high melting point, excellent chemical stability, and good physical compatibility with the metal matrix, while their density is only 3 / 5 that of tungsten carbide cemented carbide. This makes them highly suitable for the high wear and corrosion resistance requirements in the aforementioned engineering plastics processing applications. Currently, ternary boride cermets (such as Mo2FeB2 and Mo2NiB2) have been successfully applied to the manufacture of screws and barrels using powder metallurgy methods, giving these components excellent wear resistance and corrosion resistance.

[0006] For ternary boride cermet cylinders, a hot-fitting process is typically used to combine the alloy sleeve with a regular steel substrate, forming a composite structure with an inner wall of ternary boride cermet and an outer steel surface. While this method is simple in principle, the manufacturing process is complex, requiring high dimensional accuracy and straightness of the inner diameter of the substrate and the outer diameter of the alloy tube, as well as a high level of operator skill.

[0007] Laser cladding technology, especially laser cladding on the inner wall of the feeding component cylinder, still faces two major challenges due to the limitation of the inner hole space size: Powder Preparation: Currently, traditional alloy powders for laser cladding are mostly produced using a melting-atomization process. Although ternary boride cermet powders can also be prepared using melting-atomization, the cermet phase usually needs to be generated through in-situ reaction. During the reaction, the liquid phase decreases as the ceramic phase precipitates, increasing the system's melting point and requiring higher melting temperatures. Furthermore, nozzle clogging is highly likely during atomization. Therefore, melting-atomization is not the preferred process for preparing this type of powder. While rotating electrode atomization avoids nozzle clogging, it is costly. More importantly, ternary boride cermet powders that have undergone high-temperature melting-atomization suffer severe ablation during subsequent laser cladding, reducing the wear and corrosion resistance of the ceramic layer.

[0008] Process Adaptation: Due to the high melting point of ternary borides, compatible laser process parameters must be used to promote in-situ generation of the hard phase and achieve grain refinement. Simultaneously, it is necessary to ensure a defect-free metallurgical bond between the coating and the inner substrate, and to strictly control heat input to suppress workpiece deformation.

[0009] Therefore, developing a targeted ternary boride composite powder and its compatible inner wall laser cladding process is of urgent technical necessity and significant application value for completely solving the long-term wear and corrosion resistance problem of engineering plastic feeding components. Summary of the Invention

[0010] The purpose of this invention is to provide a ternary boride Mo2NiB2 cermet and its preparation method, as well as an alloy barrel and its preparation method. Firstly, it addresses the drawbacks of high processing difficulty and high scrap rate in the production and use of ternary boride alloy barrels prepared using a nesting process, by providing a new preparation process. Secondly, it aims to overcome the defects and shortcomings of existing cladding materials and processes, such as traditional three alloys and tungsten carbide reinforced alloys, when applied to strengthen the inner wall of feeding barrels.

[0011] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a ternary boride Mo2NiB2 cermet, composed of the following components by mass fraction: B 3~6%, Cr 3~10%, Mo 32~58%, V 1~5%, Mn 1~4%, Nb 0.1~2%, W 0.5~3%, C 0.2~0.8%, Ni is the balance.

[0012] Furthermore, in the aforementioned ternary boride Mo2NiB2 cermet, the particle size of the ternary boride Mo2NiB2 cermet is 80~270 mesh.

[0013] This invention also provides a method for preparing ternary boride Mo2NiB2 cermet, comprising the following steps: 1) Mix the metal raw materials, binder and solvent according to the mass fraction, and ball mill to obtain a slurry; 2) The slurry is diluted and then spray-granulated, and the solvent is vaporized to obtain atomized powder coated with binder; 3) The atomized powder coated with the binder is sequentially degreased and sintered, and then vacuum sintered to obtain a block material; the block material is sequentially crushed and sieved to obtain a ternary boride Mo2NiB2 metal ceramic.

[0014] Furthermore, in the preparation method, in step 1), the binder includes one or more of PEG, paraffin, rubber, and resin, and the mass of the binder is 3-8% of the mass of the metal raw material; In step 1), the average particle size of the solids in the slurry is 3~10μm.

[0015] Furthermore, in the preparation method, in step 2), the solid-liquid volume ratio of the diluted slurry is 1:1.5~2.5.

[0016] Furthermore, in the preparation method, in step 3), the degreasing and sintering conditions include: a sintering temperature of 150~800℃, positive pressure degreasing or negative pressure degreasing, an absolute pressure of >0.1MPa for positive pressure degreasing, and a pressure of 200~400Pa for negative pressure degreasing. In step 3), the conditions for vacuum sintering include: a vacuum degree of 10... -1 ~10 -2 Pa, sintering temperature is 1000~1200℃, holding time is 120~500min.

[0017] Furthermore, in the preparation method, after sieving in step 3), the powder is further subjected to a powder spheroidization process, which is performed using a plasma spheroidization process.

[0018] The present invention also provides an alloy barrel, comprising a barrel substrate and a reinforcing layer covering the inner wall of the barrel, the reinforcing layer being obtained by cladding a ternary boride Mo2NiB2 cermet.

[0019] This invention also provides a method for preparing an alloy barrel, comprising the following steps: After pre-treating the inner wall of the barrel substrate, the cladding area is preheated, laser cladding is performed under synchronous preheating conditions, and then annealing is performed to obtain an alloy barrel containing a reinforcing layer. The laser cladding material used is a ternary boride Mo2NiB2 metal ceramic; The laser cladding gun used for laser cladding is equipped with a coaxial powder-feeding laser cladding head, and a medium-frequency heating coil is integrated in front of the laser cladding gun. The barrel substrate is fixed to the spindle machine tool and rotates at a constant speed; the laser cladding gun moves at a constant speed in a straight line along the axis of the barrel substrate.

[0020] Furthermore, in the preparation method, the preheating is to maintain the temperature of the substrate cladding area at 500~800℃; The conditions for laser cladding include: laser power of 1400~2000W, scanning speed of 300~500mm / min, powder feeding rate of 7~12g / min, and overlap rate of 30~60%; The protective gas used in the laser cladding is argon, and the flow rate of the protective gas is 15~30L / min; The annealing process is carried out at a temperature of 400~600℃ and a holding time of 2~4h.

[0021] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects: This invention provides a ternary boride Mo2NiB2 laser cladding powder. It features a proprietary powder composition and is prepared using powder metallurgy sintering pre-alloying and plasma powder spheroidization processes. This ensures that during the non-equilibrium process of rapid laser melting and solidification, the powder can generate a structurally stable, uniformly dispersed, high-hardness ternary boride hard phase in situ during cladding, imparting excellent abrasive wear resistance and corrosion resistance to the alloy layer. Simultaneously, it provides an optimized process method compatible with this dedicated powder, suitable for laser cladding on the inner walls of feeding cylinders, especially on the inner walls of tubular components with large aspect ratios, ensuring the acquisition of a dense, metallurgically bonded, and high-performance reinforced layer. The core of this invention lies in combining dedicated internal hole laser cladding equipment, specially formulated ternary boride Mo2NiB2 cermet powder, and an optimized process integrating synchronous preheating to form a collaborative technical equipment system. This overcomes the technical bottlenecks of internal wall cladding, ensuring the acquisition of a dense, firmly bonded, and uniformly performing reinforced layer.

[0022] 1) Innovative coating material: Specifically optimized for laser cladding processes, it can reliably generate ternary boride hard phases in situ. This hard phase has extremely high hardness, good chemical stability, and better compatibility with the metal matrix than tungsten carbide, avoiding the large-scale generation of harmful brittle phases.

[0023] 2) Excellent comprehensive performance: The prepared cladding layer is a typical metal-ceramic composite material structure, which has both ultra-high hardness (macro hardness HRC 55~60) and good toughness, and also has excellent resistance to corrosion by plastic decomposition products.

[0024] 3) Strong process adaptability: The disclosed process parameter range is specifically optimized for the powder under the inner wall cladding condition, which can effectively solve special problems such as energy density maintenance, melt pool protection and cooling rate control in inner wall cladding, and ensure that a high-quality coating with uniform composition, structure and performance is obtained on the inner wall.

[0025] 4) High application value: The powder and method of this invention can be used to directly perform high-performance repair on the inner wall of worn feeding components, or to strengthen the pretreatment of newly manufactured parts, significantly extending their service life. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0027] Figure 1 Metallographic image of the ternary boride reinforced layer obtained in Example 1; Figure 2 This is a schematic diagram of the overall laser cladding device; Figure 3 This is a schematic diagram of the cladding gun in a laser cladding device. Figure 4 This is a schematic diagram of the gun tail assembly of a laser cladding device; Figure 5 A schematic diagram of the main body of the laser cladding device's gun head; Figure 6 This is a schematic diagram of the laser cladding device's gun head assembly; Among them, 1-spindle machine tool; 2-chuck; 3-integrated heating device; 4-cladding gun; 5-slide rail; 6-roller assembly; 7-base; 8-center frame; 9-control panel; 10-three-axis transmission table; 11-gun tail assembly; 1101-optical lens mount; 1102-focusing structure; 1103-protection module; 12-gun body assembly; 13-gun head assembly; 1301-gun head body; 1302-powder feeding pipe; 1303-conical light outlet; 1304-copper mirror. Detailed Implementation

[0028] This invention provides a ternary boride Mo2NiB2 cermet, composed of the following components by mass fraction: B 3~6%, Cr 3~10%, Mo 32~58%, V 1~5%, Mn 1~4%, Nb 0.1~2%, W 0.5~3%, C 0.2~0.8%, Ni is the balance.

[0029] In this invention, the mass fraction of boron (B) in the ternary boride Mo2NiB2 cermet is preferably 3.5-5.5%, more preferably 4-5%, and even more preferably 4.5%.

[0030] In this invention, the mass fraction of Cr (chromium) in the ternary boride Mo2NiB2 cermet is preferably 5-8%, more preferably 6-7%, and even more preferably 6.5%.

[0031] In this invention, the mass fraction of Mo (molybdenum) in the ternary boride Mo2NiB2 cermet is preferably 35-55%, more preferably 40-50%, and even more preferably 45%.

[0032] In this invention, the mass fraction of V (vanadium) in the ternary boride Mo2NiB2 cermet is preferably 2 to 4%, more preferably 2.5 to 3.5%, and even more preferably 3%.

[0033] In this invention, the mass fraction of Mn (manganese) in the ternary boride Mo2NiB2 cermet is preferably 1.5 to 3.5%, more preferably 2 to 3%, and even more preferably 2.5%.

[0034] In this invention, the mass fraction of Nb (niobium) in the ternary boride Mo2NiB2 cermet is preferably 0.5-1.5%, more preferably 0.8-1.2%, and even more preferably 1%.

[0035] In this invention, the mass fraction of W (tungsten) in the ternary boride Mo2NiB2 cermet is preferably 1 to 2.5%, more preferably 1.5 to 2%, and even more preferably 1.7%.

[0036] In this invention, the mass fraction of C (carbon) element in the ternary boride Mo2NiB2 cermet is preferably 0.3~0.7%, more preferably 0.4~0.6%, and even more preferably 0.5%.

[0037] In this invention, the particle size of the ternary boride Mo2NiB2 cermet is preferably 80-270 mesh. This particle size range provides a certain degree of flowability, meeting the requirements of laser cladding.

[0038] This invention also provides a method for preparing ternary boride Mo2NiB2 cermet, comprising the following steps: 1) Mix the metal raw materials, binder and solvent according to the mass fraction, and ball mill to obtain a slurry; 2) The slurry is diluted and then spray-granulated, and the solvent is vaporized to obtain atomized powder coated with binder; 3) The atomized powder coated with the binder is sequentially degreased and sintered, and then vacuum sintered to obtain a block material; the block material is sequentially crushed and sieved to obtain a ternary boride Mo2NiB2 metal ceramic.

[0039] In this invention, in step 1), the adhesive preferably includes one or more of PEG, paraffin wax, rubber, and resin, more preferably includes PEG, paraffin wax, rubber, or resin, and more preferably paraffin wax.

[0040] In this invention, in step 1), the mass of the binder is preferably 3 to 8% of the mass of the metal raw material, more preferably 4 to 6%, and even more preferably 5%.

[0041] In this invention, the type and amount of solvent used in step 1) are not limited. Any solvent that does not chemically react with the raw materials and is well-known in the art can be used to enable ball milling. Specifically, in the embodiments of this application, the solvent is anhydrous ethanol.

[0042] In this invention, in step 1), the ball milling method is preferably a horizontal ball mill, a planetary ball mill, a stirred ball mill, or a vibratory ball mill, and more preferably a vibratory ball mill. Vibratory ball mills have the advantages of high loading capacity, high milling efficiency, good heat dissipation, and convenient ball-liquid separation.

[0043] In this invention, in step 1), the average particle size of the solids in the slurry is preferably 3~10μm, more preferably 5~8μm, and even more preferably 7μm.

[0044] In this invention, in step 2), the solid-liquid volume ratio of the diluted slurry is preferably 1:1.5~2.5, more preferably 1:1.5~2, and even more preferably 1:1.5. The slurry is thoroughly stirred after dilution to maintain a uniform concentration and prevent precipitation or segregation.

[0045] In this invention, in step 2), the conditions for spray granulation include: a drying temperature preferably of 85-100℃, more preferably 85-90℃, and even more preferably 85℃; a centrifugal nozzle rotation speed preferably of 150-250Hz, more preferably 180-220Hz, and even more preferably 200Hz; and a feed pump speed preferably of 5-15Hz, more preferably 8-12Hz, and even more preferably 10Hz. After dilution, the slurry is pumped to a high-speed centrifugal nozzle. Under centrifugal force, the droplets are thrown out and broken. During the descent, the solvent is instantly vaporized under the action of the high-temperature airflow, and the solid material forms well-spherical powder particles coated with the binder. The atomized particle size is adjusted by regulating the rotation speed of the high-speed centrifugal nozzle and the feed pump speed. The particles are then cooled in a cooling bed and sieved and packaged.

[0046] In this invention, step 3) includes the following conditions for degreasing and sintering: the sintering temperature is preferably 150~800℃, more preferably 300~600℃, and even more preferably 350℃; positive pressure degreasing or negative pressure degreasing; the absolute pressure of positive pressure degreasing is >0.1MPa, not specifically limited, and can be slightly higher than one standard atmosphere; the pressure of negative pressure degreasing is preferably 200~400Pa, more preferably 200~300Pa, and even more preferably 200Pa. The purpose of degreasing and sintering is to remove the binder from the powder.

[0047] In this invention, in step 3), the conditions for vacuum sintering include: the vacuum degree is preferably 10. -1 ~10 -2 Pa, more preferably 10 Pa -1 ~5×10 -2 Pa, more preferably 10 Pa -1 Pa; the sintering temperature is preferably 1000~1200℃, more preferably 1000~1100℃, and even more preferably 1000℃; the holding time is preferably 120~500min, more preferably 120~200min, and even more preferably 120min. During this process, the carbon in the raw material powder undergoes a reduction reaction with oxygen, reducing the carbon and oxygen content in the powder, while slowly generating the Mo2NiB2 ceramic hard phase in situ, which forms a loosely structured block material after cooling.

[0048] In this invention, the crushing in step 3) is preferably performed using a double-roll crusher. The conditions for the double-roll crushing are not particularly limited; any method well-known in the art can be used. To reduce oxidation due to temperature increases during the crushing process, a low-energy crushing method is typically employed, such as double-roll crushing.

[0049] In this invention, after sieving in step 3), the powder is preferably further subjected to spheroidization treatment. The powder spheroidization treatment employs a plasma spheroidization process. The parameters of the plasma spheroidization process are not specifically limited; any scheme well-known in the art can be used. After the above steps, although the powder meets the requirements of laser cladding, the powder morphology is not very regular, exhibiting hollow powder, polygonal powder, satellite powder, etc. To further improve the powder morphology, increase the sphericity and packing density of the powder, and increase fluidity, thereby improving the compactness and wear and corrosion resistance of the cladding alloy layer, the above-mentioned powder is further spheroidized. Because the raw material contains a large amount of molybdenum and ternary borides, the melting point is relatively high, and a plasma spheroidization process is usually adopted. The powder is fed into a high-temperature plasma torch (temperatures can reach over 6000℃), where the powder particles melt instantly and shrink into spheres under the action of surface tension. Subsequently, they are rapidly cooled and solidified in an inert atmosphere to obtain ternary boride Mo2NiB2 cermet powder with high sphericity and high fluidity. However, the plasma spheroidization process is very expensive, which instantly increases the manufacturing cost of the powder. Usually, after steps 1) to 3), the ternary boride Mo2NiB2 cermet powder prepared can meet the requirements of subsequent laser cladding.

[0050] In this invention, for ternary boride Mo2NiB2 cermets, drying is preferably performed before use. The conditions include: a drying temperature preferably of 200-300°C, more preferably 200-230°C, and even more preferably 210°C; and a holding time preferably of 30-60 min, more preferably 40-50 min, and even more preferably 45 min. The purpose of drying is to thoroughly remove moisture adsorbed on the powder surface to prevent the formation of pores during the cladding process.

[0051] The present invention also provides an alloy barrel, comprising a barrel substrate and a reinforcing layer covering the inner wall of the barrel, the reinforcing layer being obtained by cladding a ternary boride Mo2NiB2 cermet.

[0052] This invention also provides a method for preparing an alloy barrel, comprising the following steps: After pre-treating the inner wall of the barrel substrate, the cladding area is preheated, laser cladding is performed under synchronous preheating conditions, and then annealing is performed to obtain an alloy barrel containing a reinforcing layer. The laser cladding material used is a ternary boride Mo2NiB2 metal ceramic; The laser cladding gun used for laser cladding is equipped with a coaxial powder-feeding laser cladding head, and a medium-frequency heating coil is integrated in front of the laser cladding gun. The barrel substrate is fixed to the spindle machine tool and rotates at a constant speed; the laser cladding gun moves at a constant speed in a straight line along the axis of the barrel substrate.

[0053] In this invention, the material of the barrel base is preferably non-quenched and tempered steel. The types of non-quenched and tempered steel include, but are not limited to, 45MnSiV (other types of non-quenched and tempered steel well known in the art are also included within the scope of this invention). The barrel base is preferably a cylindrical or tubular feeding component (including but not limited to extruder barrels, screws, and figure-eight sleeves). This invention does not impose any special limitations on the specifications of the barrel; adjustments can be made according to requirements. In embodiments of this invention, the preferred specification is the outer diameter. 90~120mm, inner diameter 40~56mm, length 900~2000mm, more preferably 100 or 120 mm, inner diameter 42, 46 or 56 mm, length 1000 or 1400 mm.

[0054] In this invention, the pretreatment preferably involves turning the inner wall of the barrel substrate to ensure its rotational concentricity and straightness, while removing the surface oxide layer. Subsequently, it is cleaned with anhydrous ethanol to remove oil and cutting residue, and then dried to obtain a barrel substrate with a clean inner surface, high geometric accuracy, and good activity. The treated barrel substrate is then clamped onto a machine tool. This invention does not impose any specific limitations on the specific operation process of the pretreatment; any process well-known in the art can be followed.

[0055] In this invention, the preheating is preferably maintained at 500~800℃, more preferably 500~700℃, and even more preferably 600℃ in the substrate cladding area. Before the cladding gun starts working, the synchronous preheating system is turned on, and the process parameters are set and optimized. By using the medium-frequency heating coil integrated in front of the cladding gun to synchronously preheat the substrate in the cladding area and stably maintain the temperature of this area within the above range, the cooling rate and thermal stress of subsequent laser cladding can be significantly reduced, effectively suppressing the tendency of the coating to crack.

[0056] In this invention, the laser cladding conditions include: laser power preferably 1400~2000W, more preferably 1500~1800W, and even more preferably 1600W; scanning speed preferably 300~500mm / min, more preferably 350~450mm / min, and even more preferably 400mm / min; powder feeding rate preferably 7~12g / min, more preferably 8~10g / min, and even more preferably 9g / min; and overlap rate preferably 30~60%, more preferably 40~60%, and even more preferably 50%. Under these parameters, the powder and the preheated substrate surface melt together to form a molten pool. During the controlled cooling process, fine ternary boride hard phases precipitate in situ from the melt and are uniformly distributed in the strong and tough metal substrate, ultimately forming a metallurgically bonded composite coating.

[0057] In this invention, the laser power is determined based on the spot size, powder feeding amount, and scanning speed; the scanning speed is determined based on the linear velocity of the rotating barrel substrate.

[0058] In this invention, the protective gas and powder feeding gas used for laser cladding are preferably argon (high-purity argon with a purity of 99.999%); the flow rate of the protective gas is preferably 15~30L / min, more preferably 20~30L / min, and even more preferably 25L / min; the flow rate of the powder feeding gas is preferably 2~6L / min, more preferably 3~5L / min, and even more preferably 4L / min.

[0059] like Figures 2-6 As shown, the laser cladding device used in the laser cladding process of the present invention includes a base 7, a spindle machine tool 1, a three-axis transmission table 10, a cladding gun 4, an integrated heating device 3, a control panel 9, a roller assembly 6, and a center frame 8.

[0060] A slide rail 5 is installed on the base 7 along its length. The spindle machine tool 1 is fixed to one end of the base 7 by bolts. A chuck 2 is driven and connected to the spindle machine tool 1 to hold the workpiece to be processed.

[0061] The three-axis drive table 10 is mounted on the slider of the slide rail 5 and can move along the length direction of the slide rail 5 (X-axis), moving closer to or away from the main spindle machine tool 1. A vertical guide rail (Z-axis) is mounted on the three-axis drive table 10, and a horizontal guide rail is fixed on the slider of the vertical guide rail. A cladding gun 4 is mounted on the slider of the horizontal guide rail (Y-axis).

[0062] Specifically, the cladding gun 4 includes: a gun head assembly 13, a gun body assembly 12, and a gun tail assembly 11.

[0063] The tail assembly 11 includes an optical lens mount 1101, a focusing structure 1102, and a protection module 1103 connected in sequence. The optical lens mount 1101 is connected to an optical fiber and mounted on a slider of a horizontal guide rail. The focusing structure 1102 contains an optical element box adjustment ring. By driving the adjustment ring, the optical element can be slightly displaced along the optical axis, thereby achieving precise adjustment of the emitted laser spot size. The protection module 1103 contains a protective lens to protect the optical lens mount 1101 and the focusing structure 1102. The body assembly 12 is made of a metal tube, which is mounted on the protection module 1103. Multiple focusing lenses are arranged inside the metal tube along the laser transmission direction. The head assembly 13 includes a head body 1301, on which a copper mirror 1304 and a conical light-emitting nozzle 1303 are arranged. Powder feeding tubes 1302 are arranged on both sides of the conical light-emitting nozzle 1303. The powder feeding pipe 1302 is connected to a powder feeding system via a powder feeding pipeline. The powder feeding system can deliver alloy powder to the powder feeding pipe 1302 in a dry, uniform, and continuous state and then eject it. The conical light-emitting nozzle 1303 is connected to a gas supply system via a gas supply pipeline. The conical light-emitting nozzle 1303 guides inert protective gas (such as argon) along the conical surface to the molten pool area. This not only effectively suppresses alloy powder splashing and protects the copper mirror 1304, but also creates a local high-concentration inert gas environment above the molten pool, thereby preventing alloy oxidation.

[0064] Specifically, the 1304 copper mirror integrates a high-efficiency water-cooling channel to ensure minimal thermal deformation during long-term operation and prevent focus drift.

[0065] Specifically, the gun body assembly 12 is composed of multiple coaxially arranged high-temperature and corrosion-resistant metal tubes connected in sequence. Each metal tube is inlaid with a focusing lens, forming an independent optical functional segment, which facilitates quick replacement or maintenance for different inner hole depths.

[0066] In this embodiment, a support rod parallel to the cladding gun 4 is also provided on the horizontal guide rail, and an integrated heating device 3 is provided at the other end of the support rod. The integrated heating device 3 includes an induction heating coil and an infrared thermometer. The outside of the induction heating coil is wrapped with a heat insulation layer, and the induction heating coil is connected to a heating power supply. The integrated heating device 3 can achieve precise thermal control of the cladding area from preheating, heat tracing to slow cooling. This active thermal management strategy can effectively reduce the cooling rate, homogenize the temperature gradient, and release residual stress, ensuring that even for high-hardness and high-brittle materials such as nickel-based tungsten carbide, a completely crack-free alloy layer with good metallurgical bonding can be obtained, and the hardness of the alloy layer can stably reach HRC 55~65.

[0067] The control panel 9 is installed on the side of the base 7. It adopts a PLC control system and is equipped with a touch screen. It can display and set parameters such as spindle speed, three-axis transmission table 10 movement speed, laser power, powder feeding amount, air supply pressure, and heating temperature in real time. The control panel 9 is electrically connected to the spindle machine tool 1, three-axis transmission table 10, cladding gun 4, laser emitter, focusing structure 1102, air supply system, powder feeding system, and the heating power supply and infrared thermometer of the integrated heating device 3 to achieve coordinated control.

[0068] In this invention, the laser cladding device used in the laser cladding process includes: Internal Hole Laser Cladding Gun: Employs a coaxial powder-feeding laser cladding head suitable for operation within deep holes in barrels. Its compact radial dimensions allow it to extend into and adapt to the inner walls of deep-hole components such as barrels. This cladding gun integrates a laser transmission fiber / optical path, a coaxial powder delivery channel, and multi-layer protective gas paths, enabling the creation of an annular molten pool and cladding channel under compact radial dimensions.

[0069] Preheating system (including induction heating coil, integrated heating device 3; heating device controls heating power, heating coil realizes preheating): a medium frequency heating coil is integrated in front of the cladding gun 4, which performs precise and continuous synchronous preheating of the substrate in the cladding area while laser cladding is being carried out.

[0070] Motion control system (spindle machine tool 1 and three-axis transmission table 10): The barrel base is fixed to the spindle machine tool and rotates at a constant speed; the inner hole cladding gun moves at a constant speed in a straight line along the axis of the barrel base through a precision slide table. The two combine to form a spiral cladding trajectory. The control system integrates and links the laser, powder feeder, preheating system and motion axis for linkage control.

[0071] In this invention, the annealing temperature is preferably 400~600℃, more preferably 500~600℃, and even more preferably 600℃; the holding time is preferably 2~4h, more preferably 2.5~3.5h, and even more preferably 3h. Purpose: After laser cladding and before finishing, a specialized heat treatment eliminates residual thermal stress accumulated within the cladding layer, stabilizes the microstructure, and prevents coating cracking or deformation due to stress release during subsequent processing or use. Function and Effect: This step, as an independent heat treatment process after cladding, systematically reduces and homogenizes the high internal stress caused by rapid laser heating and cooling, further improving the dimensional stability of the coating and the reliability of its bonding with the substrate, providing a stable workpiece state for subsequent precision machining.

[0072] In this invention, the inner surface of the annealed cladding layer is precision-machined (e.g., ground or honed) to achieve the required dimensional accuracy and surface roughness for engineering purposes. The precision-machined method is not limited; any solution well-known in the art can be used.

[0073] For other unrestricted conditions of this invention, solutions well known in the art may be used.

[0074] 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.

[0075] Example 1

[0076] I) Preparation of composite powder

[0077] 1. Ingredients: Add each chemical element to the ball mill jar according to the following mass percentage: B 3%, Cr 3%, Mo 32%, V 1%, Mn 1%, Nb 0.1%, W 0.5%, C 0.2%, Ni balance; 2. Ball milling: The raw materials were put into a ball mill jar, and 3wt% of the binder paraffin and 10L of anhydrous ethanol were added as solvent. Wet ball milling was carried out for 24 hours to obtain a slurry with an average particle size of 3μm. 3. Spray granulation and drying: Dilute the slurry and pour it into the spray drying tower tank. Stir thoroughly to maintain the uniform concentration of the slurry and prevent precipitation and segregation. The solid-liquid volume ratio is controlled at 1:1.5. The slurry is sent to the high-speed centrifugal nozzle by the feed pump. The spray granulation conditions are: drying temperature 85℃, centrifugal nozzle speed 200Hz, and feed pump speed 10Hz. Under the action of centrifugal force, the droplets are thrown out and broken. During the descent, the solvent is instantly vaporized under the action of high-temperature airflow. The solid material forms powder particles with good sphericity and coated with binder. 4. Debinding and Sintering: The atomized powder is divided into alumina ceramic crucibles and placed into a debinding and sintering furnace. The temperature is gradually increased by 150℃ to vaporize the binder. The binder in the powder is removed by a negative pressure debinding method at 200 Pa. Then, the powder enters the vacuum sintering stage with a vacuum degree of 10. -1 Pa, continue heating to 1000℃ and hold for 120 min. During this process, carbon and oxygen in the raw material powder undergo a reduction reaction, reducing the carbon and oxygen content in the powder to <0.1%. At the same time, Mo2NiB2 ceramic hard phase is slowly generated in situ, and after cooling, it forms a loosely structured block material. 5. Crushing and screening: After cooling to room temperature, remove the block material, crush it into powder using a double roll crusher, and screen it to 80~270 mesh to obtain ternary boride Mo2NiB2 metal ceramic powder that meets the requirements of laser cladding; 6. Drying treatment: Place the ternary boride Mo2NiB2 cermet powder in a drying oven, slowly raise the temperature to 210℃, and keep it at that temperature for 30 minutes to completely remove the moisture adsorbed on the powder surface and prevent the formation of pores during the cladding process.

[0078] II) Pretreatment of the barrel substrate

[0079] 1. Material preparation: Select specifications based on outer diameter 100mm, inner diameter A 42mm thick, 1000mm long non-quenched and tempered steel barrel (specifically made of 45MnSiV) is used as the base material; 2. Boring: The inner wall of the barrel is bored. The key objective is to ensure the straightness of the inner wall and the concentricity of the inner and outer diameters. After machining, the inner wall has a uniform silver-gray metallic surface. 3. Cleaning: Use anhydrous ethanol to thoroughly clean the inner wall of the barrel to remove oil and cutting residue, and then dry it to obtain a barrel substrate with a clean inner surface, high geometric accuracy, and good activity; 4. Clamping: The material cylinder base material is clamped with jaws, and the other end is supported by a center frame. The micrometer is used for alignment, and the inner hole runout is controlled to be <0.1mm.

[0080] III) Laser Cladding Strengthening Process

[0081] Equipment and core process parameters: Laser system: Fiber-coupled laser; Cladding system: a dedicated internal laser cladding gun with an integrated medium-frequency induction heating coil at the front end for synchronous preheating; Motion system: Four-axis linkage machine tool (capable of machining internal holes of 1~4 meters and external holes of 1~8 meters); The core process parameters are shown in Table 1.

[0082] Table 1. Laser cladding parameters for Example 1

[0083] step: 1. Clamping and calibration: Clamp the pretreated barrel onto the machine tool spindle, start the spindle rotation, and use a dial indicator to measure the radial runout of the inner wall to ensure that the runout does not exceed 0.1mm to meet the requirements of cladding uniformity; 2. Equipment alignment: Insert the inner hole laser cladding gun into one end of the material cylinder, adjust the laser focal length to the optimal working distance (3mm), and accurately position the relative axial distance between the induction heating coil and the laser cladding focal point to ensure that the preheating area matches the cladding area; 3. Simultaneous preheating and cladding: Turn on the induction heating system to heat the substrate, and wait for the infrared thermometer to show that the temperature of the target area is stable within 500℃. Simultaneously start the laser, powder feeder, and protective gas system; Start the machine tool program, the barrel rotates at a constant speed, and the cladding gun feeds at a constant speed along the axis. The two combine to form a spiral scanning path and start automatic cladding. 4. Process execution: The system runs continuously until it covers the entire inner wall length of the target (1000mm). 5. Gradient slow cooling: After the cladding process is completed, first turn off the laser and powder feeder, keep the protective gas flowing, and control the induction heating system to slowly cool down to 200°C in a step-down mode. Finally, turn off all systems and let the workpiece cool down to room temperature naturally in the heat preservation environment. Results: A bright, uniform, macroscopically crack-free cladding layer was obtained on the inner wall of the barrel. Measurements showed that the thickness of the cladding layer in a single molding process was 1-2 mm, with a machining allowance of approximately 0.5 mm.

[0084] IV) Intermediate stress-relief annealing

[0085] After the laser cladding strengthening process is completed, the workpiece in the cylinder, which has been slowly cooled to room temperature, is transferred to a holding furnace.

[0086] 1. Heating: The furnace temperature is uniformly raised to 600℃ at a rate of 150℃ / h; 2. Heat preservation: Keep the workpiece at this temperature for 2 hours to ensure uniform temperature throughout the workpiece and to complete the stress relaxation and microstructure stabilization process; 3. Slow cooling: After the heat preservation is completed, cut off the heating power supply and allow the workpiece to cool slowly to room temperature with the furnace.

[0087] V) Post-processing (finishing)

[0088] The workpiece, which has been slowly cooled to room temperature, is clamped in a precision CNC internal grinding machine. The inner wall of the cladding layer is then finely ground according to a preset program to remove the reserved machining allowance, ultimately achieving the dimensional tolerances and surface roughness required by the drawing.

[0089] Final result: A high-wear-resistant, long-life injection molding machine barrel with an inner wall covered by a high-performance ternary boride reinforced layer was obtained. The coating of Example 1 is denoted as JN58.

[0090] Example 2

[0091] I) Preparation of composite powder

[0092] 1. Ingredients: Add each chemical element to the ball mill jar according to the following mass percentage: B 4.5%, Cr 6.5%, Mo 45%, V 3%, Mn 2.5%, Nb 1%, W 1.7%, C 0.5%, Ni balance; 2. Ball milling: The raw materials were put into a ball mill jar, and 5 wt% of paraffin wax as a binder and 12.5 L of anhydrous ethanol as a solvent were added. Wet ball milling was carried out for 36 hours to obtain a slurry with an average particle size of 5 μm. 3. Spray granulation and drying: Dilute the slurry and pour it into the spray drying tower tank. Stir thoroughly to maintain the uniform concentration of the slurry and prevent precipitation and segregation. The solid-liquid volume ratio is controlled at 1:1.5. The slurry is sent to the high-speed centrifugal nozzle by the feed pump. The spray granulation conditions are: drying temperature 90℃, centrifugal nozzle speed 150Hz, and feed pump speed 5Hz. Under the action of centrifugal force, the droplets are thrown out and broken. During the descent, the solvent is instantly vaporized under the action of high-temperature airflow. The solid material forms powder particles with good sphericity and coated with binder. 4. Debinding and Sintering: The atomized powder is divided into alumina ceramic crucibles and placed into a debinding and sintering furnace. The temperature is gradually increased to 350℃ to vaporize the binder. The binder in the powder is removed by a negative pressure debinding method at 300 Pa. Then, the powder enters the vacuum sintering stage with a vacuum degree of 10. -2 Pa, continue heating to 1000℃ and hold for 120 min. During this process, carbon and oxygen in the raw material powder undergo a reduction reaction, reducing the carbon and oxygen content in the powder to <0.1%. At the same time, Mo2NiB2 ceramic hard phase is slowly generated in situ, and after cooling, it forms a loosely structured block material. 5. Crushing and screening: After cooling to room temperature, remove the block material, crush it into powder using a double roll crusher, and screen it to 80~270 mesh to obtain ternary boride Mo2NiB2 metal ceramic powder that meets the requirements of laser cladding; 6. Drying treatment: Place the ternary boride Mo2NiB2 cermet powder in a drying oven, slowly raise the temperature to 210℃, and keep it at that temperature for 45 minutes to completely remove the moisture adsorbed on the powder surface and prevent the formation of pores during the cladding process.

[0093] II) Pretreatment of the barrel substrate

[0094] 1. Material preparation: Select specifications based on outer diameter 100mm, inner diameter A 46mm thick, 1400mm long non-quenched and tempered steel barrel (specifically made of 45MnSiV) was used as the base material; 2. Boring: The inner wall of the barrel is bored. The key objective is to ensure the straightness of the inner wall and the concentricity of the inner and outer diameters. After machining, the inner wall has a uniform silver-gray metallic surface. 3. Cleaning: Use anhydrous ethanol to thoroughly clean the inner wall of the barrel to remove oil and cutting residue, and then dry it to obtain a barrel substrate with a clean inner surface, high geometric accuracy, and good activity; 4. Clamping: The material cylinder base material is clamped with jaws, and the other end is supported by a center frame. The micrometer is used for alignment, and the inner hole runout is controlled to be <0.1mm.

[0095] III) Laser Cladding Strengthening Process

[0096] Equipment and core process parameters: Laser system: Fiber-coupled laser; Cladding system: a dedicated internal laser cladding gun with an integrated medium-frequency induction heating coil at the front end for synchronous preheating; Motion system: Four-axis linkage machine tool (capable of machining internal holes of 1~4 meters and external holes of 1~8 meters); The core process parameters are shown in Table 2. Table 2. Laser cladding parameters for Example 2

[0097] step: 1. Clamping and calibration: Clamp the pretreated barrel onto the machine tool spindle, start the spindle rotation, and use a dial indicator to measure the radial runout of the inner wall to ensure that the runout does not exceed 0.1mm to meet the requirements of cladding uniformity; 2. Equipment alignment: Insert the inner hole laser cladding gun into one end of the material cylinder, adjust the laser focal length to the optimal working distance (3mm), and accurately position the relative axial distance between the induction heating coil and the laser cladding focal point to ensure that the preheating area matches the cladding area; 3. Simultaneous preheating and cladding: Turn on the induction heating system to heat the substrate, and wait for the infrared thermometer to show that the temperature of the target area stabilizes within the range of 600℃; Simultaneously start the laser, powder feeder, and protective gas system; Start the machine tool program, the barrel rotates at a constant speed, and the cladding gun feeds at a constant speed along the axis. The two combine to form a spiral scanning path and start automatic cladding. 4. Process execution: The system runs continuously until it covers the entire inner wall length of the target (1400mm). 5. Gradient slow cooling: After the cladding process is completed, first turn off the laser and powder feeder, keep the protective gas flowing, and control the induction heating system to slowly cool down to 200°C in a step-down mode. Finally, turn off all systems and let the workpiece cool down to room temperature naturally in the heat preservation environment. Results: A bright, uniform, macroscopically crack-free cladding layer was obtained on the inner wall of the barrel. Measurements showed that the thickness of the cladding layer in a single molding process was 1-2 mm, with a machining allowance of approximately 0.5 mm.

[0098] IV) Intermediate stress-relief annealing

[0099] After the laser cladding strengthening process is completed, the workpiece in the cylinder, which has been slowly cooled to room temperature, is transferred to a holding furnace.

[0100] 1. Heating: The furnace temperature is uniformly increased to 500℃ at a rate of 150℃ / h; 2. Heat preservation: Keep the workpiece at this temperature for 3 hours to ensure uniform temperature throughout the workpiece and to complete the stress relaxation and microstructure stabilization process; 3. Slow cooling: After the heat preservation is completed, cut off the heating power supply and allow the workpiece to cool slowly to room temperature with the furnace.

[0101] V) Post-processing (finishing)

[0102] The workpiece, which has been slowly cooled to room temperature, is clamped in a precision CNC internal grinding machine. The inner wall of the cladding layer is then finely ground according to a preset program to remove the reserved machining allowance, ultimately achieving the dimensional tolerances and surface roughness required by the drawing.

[0103] Final result: A high-wear-resistant, long-life injection molding machine barrel with an inner wall covered by a high-performance ternary boride reinforcement layer was obtained.

[0104] Example 3

[0105] I) Preparation of composite powder

[0106] 1. Ingredients: Add each chemical element to the ball mill jar according to the following mass percentage: B 6%, Cr 10%, Mo 58%, V 5%, Mn 4%, Nb 2%, W 3%, C 0.8%, Ni balance; 2. Ball milling: The raw materials were put into a ball mill jar, and 8wt% of the binder paraffin and 15L of anhydrous ethanol were added as solvent. Wet ball milling was carried out for 80 hours to obtain a slurry with an average particle size of 7μm. 3. Spray granulation and drying: Dilute the slurry and pour it into the spray drying tower tank. Stir thoroughly to maintain uniform slurry concentration and prevent precipitation or segregation. The solid-liquid volume ratio is controlled at 1:1.5. The slurry is pumped to a high-speed centrifugal nozzle. Spray granulation conditions: drying temperature 100℃, centrifugal nozzle speed 250Hz, feed pump speed 15Hz. Under the action of centrifugal force, the droplets are thrown out and broken. During the descent, the solvent is instantly vaporized under the action of high-temperature airflow. The solid material forms spherical powder particles with good sphericity and coated with binder. 4. Debinding and Sintering: The atomized powder is divided into alumina ceramic crucibles and placed into a debinding and sintering furnace. The temperature is gradually increased to 600℃ to vaporize the binder. The binder in the powder is removed by a negative pressure debinding method at 400 Pa. Then, the powder enters the vacuum sintering stage with a vacuum degree of 10. -2 Pa, continue heating to 1200℃ and hold for 500min. During this process, carbon and oxygen in the raw material powder undergo a reduction reaction, reducing the carbon and oxygen content in the powder to <0.1%. At the same time, Mo2NiB2 ceramic hard phase is slowly generated in situ, and after cooling, it forms a loosely structured block. 5. Crushing and screening: After cooling to room temperature, remove the block material, crush it into powder using a double roll crusher, and screen it to 80~270 mesh to obtain ternary boride Mo2NiB2 metal ceramic powder that meets the requirements of laser cladding; 6. Drying treatment: Place the ternary boride Mo2NiB2 cermet powder in a drying oven, slowly raise the temperature to 210℃, and keep it at that temperature for 60 minutes to completely remove the moisture adsorbed on the powder surface and prevent the formation of pores during the cladding process.

[0107] II) Pretreatment of the barrel substrate

[0108] 1. Material preparation: Select specifications based on outer diameter 120mm, inner diameter A 56mm thick, 1400mm long non-quenched and tempered steel barrel (specifically made of 45MnSiV) was used as the base material; 2. Boring: The inner wall of the barrel is bored. The key objective is to ensure the straightness of the inner wall and the concentricity of the inner and outer diameters. After machining, the inner wall has a uniform silver-gray metallic surface. 3. Cleaning: Use anhydrous ethanol to thoroughly clean the inner wall of the barrel to remove oil and cutting residue, and then dry it to obtain a barrel substrate with a clean inner surface, high geometric accuracy, and good activity; 4. Clamping: The material cylinder base material is clamped with jaws, and the other end is supported by a center frame. The micrometer is used for alignment, and the inner hole runout is controlled to be <0.1mm.

[0109] III) Laser Cladding Strengthening Process

[0110] Equipment and core process parameters: Laser system: Fiber-coupled laser; Cladding system: a dedicated internal laser cladding gun with an integrated medium-frequency induction heating coil at the front end for synchronous preheating; Motion system: Four-axis linkage machine tool (capable of machining internal holes of 1~4 meters and external holes of 1~8 meters); The core process parameters are shown in Table 3.

[0111] Table 3. Laser cladding parameters for Example 3

[0112] step: 1. Clamping and calibration: Clamp the pretreated barrel onto the machine tool spindle, start the spindle rotation, and use a dial indicator to measure the radial runout of the inner wall to ensure that the runout does not exceed 0.1mm to meet the requirements of cladding uniformity; 2. Equipment alignment: Insert the inner hole laser cladding gun into one end of the material cylinder, adjust the laser focal length to the optimal working distance (3mm), and accurately position the relative axial distance between the induction heating coil and the laser cladding focal point to ensure that the preheating area matches the cladding area; 3. Simultaneous preheating and cladding: Turn on the induction heating system to heat the substrate, and wait for the infrared thermometer to show that the temperature of the target area stabilizes within the range of 600℃; Simultaneously start the laser, powder feeder, and protective gas system; Start the machine tool program, the barrel rotates at a constant speed, and the cladding gun feeds at a constant speed along the axis. The two combine to form a spiral scanning path and start automatic cladding. 4. Process execution: The system runs continuously until it covers the entire inner wall length of the target (1400mm). 5. Gradient slow cooling: After the cladding process is completed, first turn off the laser and powder feeder, keep the protective gas flowing, and control the induction heating system to slowly cool down to 200°C in a step-down mode. Finally, turn off all systems and let the workpiece cool down to room temperature naturally in the heat preservation environment. Results: A bright, uniform, macroscopically crack-free cladding layer was obtained on the inner wall of the barrel. Measurements showed that the thickness of the cladding layer in a single molding process was 1-2 mm, with a machining allowance of approximately 0.5 mm.

[0113] IV) Intermediate stress-relief annealing

[0114] After the laser cladding strengthening process is completed, the workpiece in the cylinder, which has been slowly cooled to room temperature, is transferred to a holding furnace.

[0115] 1. Heating: The furnace temperature is uniformly raised to 600℃ at a rate of 150℃ / h; 2. Heat preservation: Keep the workpiece at this temperature for 4 hours to ensure uniform temperature throughout the workpiece and to complete the stress relaxation and microstructure stabilization process; 3. Slow cooling: After the heat preservation is completed, cut off the heating power supply and allow the workpiece to cool slowly to room temperature with the furnace.

[0116] V) Post-processing (finishing)

[0117] The workpiece, which has been slowly cooled to room temperature, is clamped in a precision CNC internal grinding machine. The inner wall of the cladding layer is then finely ground according to a preset program to remove the reserved machining allowance, ultimately achieving the dimensional tolerances and surface roughness required by the drawing.

[0118] Final result: A high-wear-resistant, long-life injection molding machine barrel with an inner wall covered by a high-performance ternary boride reinforcement layer was obtained.

[0119] Characterization and performance testing

[0120] Figure 1 This is a metallographic image of the ternary boride reinforced layer obtained in Example 1. (From...) Figure 1 It can be seen that after etching with the etchant, the metallographic structure exhibits a distinct island-like morphology. The light-colored phase appears as irregular islands or blocks, and is relatively evenly distributed within the field of view.

[0121] Table 4 shows the comparison results of physical properties and phosphoric acid corrosion of JN58, YG8, and C350. Commercially available materials YG8 or C350 were directly used in the tests with JN58. YG8 consists of the following components by mass fraction: WC 92%, Co 8%. C350 consists of the following components by mass fraction: Ni 18%, Co 11.5%, Mo 4%, Ti 1.5%, Al 0.05%, Si≤0.10%, Mn≤0.10%, Fe balance.

[0122] Table 4. Comparison results of JN58, YG8 and C350

[0123] As shown in Table 4, JN58 has high hardness and exhibits an extremely low corrosion rate in an 85℃ constant temperature water bath and 85% phosphoric acid environment. It is an excellent corrosion-resistant material suitable for corrosive working conditions.

[0124] Table 5 shows the comparison results of friction and wear between JN58 and Ni69SM. Commercially available materials Ni69SM and JN58 were directly used for testing. Friction and wear were measured according to the national standard GB / T 12444-2006, and the test conditions are shown in Table 5. Ni69SM (Colmonoy 69SM-C) is composed of the following components by mass fraction: B 3.6%, C 0.41%, Cr 17.2%, Cu 2.1%, Fe 3.5%, Mo 3.0%, Si 5.3%, and Ni balance.

[0125] Table 5. Friction and wear results of JN58 and Ni69SM

[0126] As shown in Table 5, the wear resistance comparison shows that the mass wear of JN58 (Mo2NiB2) is 0.0018g, which is much lower than that of Ni69SM (0.0265g), representing a wear reduction of approximately 93.2%. This indicates that JN58 exhibits excellent wear resistance under the test conditions, while Ni69SM has poor wear resistance.

[0127] Relationship between hardness and wear resistance: JN58 has a hardness of 60 HRC, slightly lower than Ni69SM's 62 HRC, but its wear rate is significantly lower. This indicates that the wear resistance of a material is not solely determined by hardness, but is also closely related to the material's composition, microstructure, and wear mechanism. JN58 exhibits better resistance to abrasive wear due to the presence of hard phases (such as Mo2NiB2).

[0128] Table 6 shows the comparison results of friction and wear between JN58 and HYC3 cold work die steel. Commercially available HYC3 cold work die steel and JN58 were directly tested under the conditions shown in Table 6. HYC3 cold work die steel is composed of the following components by mass fraction: C 0.95%, Si 0.2%, Cr 6.50%, Mo 1.00%, V 1.80%, W 0.50%, Nb 0.10%, and Fe balance.

[0129] Table 6. Friction and Wear Results of JN58 and HYC3 Cold Work Die Steels

[0130] As shown in Table 6, in terms of wear resistance, the mass wear of JN58 is 0.0024g, which is lower than that of HYC3 (0.0072g), representing a wear reduction of approximately 66.7%. This indicates that JN58 exhibits superior wear resistance under the test conditions.

[0131] Relationship between hardness and wear resistance: JN58 has a hardness of 60 HRC, slightly higher than HYC3's 59 HRC, and the two are close in hardness. However, JN58 has a significantly lower wear rate, indicating that its wear resistance advantage comes not only from its hardness, but also from its Mo2NiB2 hard phase structure, which gives the material better resistance to abrasive wear.

[0132] Table 7 shows the comparison results of friction and wear between JN58 and high-vanadium tool steel 10V. Commercially available high-vanadium tool steel 10V and JN58 were directly used for testing, and the test conditions are shown in Table 7. High-vanadium tool steel 10V is composed of the following components by mass fraction: C 2.45%, Cr 5.25%, V 9.75%, Mo 1.3%, and Fe balance.

[0133] Table 7. Friction and Wear Results of JN58 and High Vanadium Tool Steel 10V

[0134] As shown in Table 7, in terms of wear resistance, the mass wear of JN58 is 0.0036g, which is lower than that of high vanadium tool steel 10V (0.0073g), representing a reduction of approximately 50.7%. This indicates that JN58 exhibits superior wear resistance under these test conditions.

[0135] Relationship between hardness and wear resistance: JN58 has a hardness of 60 HRC, slightly higher than 10V's 58 HRC, and the two are close in hardness. However, JN58 has significantly less wear, indicating that its wear resistance advantage comes not only from hardness, but also from its Mo2NiB2 hard phase structure, which may give the material better resistance to abrasive wear.

[0136] In summary, JN58 material exhibits excellent wear resistance under dry friction or similar working conditions, making it suitable for applications requiring high wear resistance.

[0137] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A ternary boride Mo2NiB2 cermet, characterized in that, It consists of the following components by mass fraction: B 3~6%, Cr 3~10%, Mo 32~58%, V 1~5%, Mn 1~4%, Nb 0.1~2%, W 0.5~3%, C 0.2~0.8%, Ni is the balance.

2. The ternary boride Mo2NiB2 cermet according to claim 1, characterized in that, The particle size of the ternary boride Mo2NiB2 cermet is 80~270 mesh.

3. The method for preparing a ternary boride Mo2NiB2 cermet according to claim 1 or 2, characterized in that, Includes the following steps: 1) Mix the metal raw materials, binder and solvent according to the mass fraction, and ball mill to obtain a slurry; 2) The slurry is diluted and then spray-granulated, and the solvent is vaporized to obtain atomized powder coated with binder; 3) The atomized powder coated with the binder is sequentially degreased and sintered, and then vacuum sintered to obtain a block material; the block material is sequentially crushed and sieved to obtain a ternary boride Mo2NiB2 metal ceramic.

4. The preparation method according to claim 3, characterized in that, In step 1), the binder includes one or more of PEG, paraffin, rubber, and resin, and the mass of the binder is 3-8% of the mass of the metal raw material; In step 1), the average particle size of the solids in the slurry is 3~10μm.

5. The preparation method according to claim 3, characterized in that, In step 2), the solid-liquid volume ratio of the diluted slurry is 1:1.5~2.

5.

6. The preparation method according to claim 3, characterized in that, In step 3), the conditions for degreasing and sintering include: sintering temperature of 150~800℃, positive pressure degreasing or negative pressure degreasing, the absolute pressure of positive pressure degreasing >0.1MPa, and the pressure of negative pressure degreasing of 200~400Pa. In step 3), the conditions for vacuum sintering include: a vacuum degree of 10... -1 ~10 -2 Pa, sintering temperature is 1000~1200℃, holding time is 120~500min.

7. The preparation method according to claim 3 or 6, characterized in that, Step 3) After sieving, the powder is further subjected to a powder spheroidization process, which is carried out using a plasma spheroidization process.

8. An alloy barrel, comprising a barrel substrate and a reinforcing layer covering the inner wall of the barrel, characterized in that, The reinforcing layer is obtained by cladding the ternary boride Mo2NiB2 cermet as described in claim 1 or 2, or the ternary boride Mo2NiB2 cermet prepared by the preparation method described in any one of claims 3 to 7.

9. The method for preparing the alloy barrel according to claim 8, characterized in that, Includes the following steps: After pre-treating the inner wall of the barrel substrate, the cladding area is preheated, laser cladding is performed under synchronous preheating conditions, and then annealing is performed to obtain an alloy barrel containing a reinforcing layer. The laser cladding material used is a ternary boride Mo2NiB2 metal ceramic; The laser cladding gun used for laser cladding is equipped with a coaxial powder-feeding laser cladding head, and a medium-frequency heating coil is integrated in front of the laser cladding gun. The barrel substrate is fixed to the spindle machine tool and rotates at a constant speed; the laser cladding gun moves at a constant speed in a straight line along the axis of the barrel substrate.

10. The preparation method according to claim 9, characterized in that, The preheating is to maintain the temperature of the substrate cladding area at 500~800℃; The conditions for laser cladding include: laser power of 1400~2000W, scanning speed of 300~500mm / min, powder feeding rate of 7~12g / min, and overlap rate of 30~60%; The protective gas used in the laser cladding is argon, and the flow rate of the protective gas is 15~30L / min; The annealing process is carried out at a temperature of 400~600℃ and a holding time of 2~4h.

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