Alloy powder, preparation method of alloy powder, brake disc and repairing method of brake disc

Abstract

The invention provides alloy powder, a preparation method of the alloy powder, a brake disc and a repairing method of the brake disc. The alloy powder comprises 0.1 wt%-2.0 wt% of Cr; 0.5 wt% to 3.0 wt% of Ni; from 0.1 wt% to 1 wt% of Mo; 0.1 wt% to 1.5 wt% of Mn; 0.01 wt% to 1.5 wt% of Si; 0.01 wt% to 1.0 wt% of C; 0 to 2.0 wt% of V; 0 to 5.0 wt% of Ti; and the balance Fe. V and Ti are not 0 at the same time. V or Ti, especially V, is added into the alloy powder, so that the alloy powder has high specific strength and excellent wear resistance and thermal fatigue resistance, the bonding strength of a coating material can be remarkably improved when the alloy powder is used for repairing a coating, and the wear resistance and thermal fatigue resistance of the coating are enhanced while the mechanical property of a matrix is maintained, so that the matrix can be effectively improved, and the service life of the coating is prolonged. For example, the overall performance of a steel-based brake disc meets the braking requirement of a high-speed train with the speed of 350 kilometers per hour.

Description

Technical Field

[0001] This invention relates to the field of alloy technology, and in particular to an alloy powder, its preparation method, a brake disc, and its repair method. Background Technology

[0002] With the rapid development of rail transit technology, the speed of high-speed trains is gradually increasing, and the performance requirements for braking systems are becoming increasingly stringent. As the core component of the high-speed train braking system, the brake disc's materials and design technology directly affect the train's safety and economy. Currently used steel-based brake discs, due to long-term operation in high-speed, high-energy environments, are prone to wear and thermal fatigue on their friction surfaces, leading to a decline in braking performance. To extend the service life of brake discs and reduce economic losses, surface coating technology has been gradually introduced into modern rail transit engineering. This involves depositing a high-performance coating material on the surface of the steel-based brake disc to improve the wear resistance and thermal fatigue resistance of the friction surfaces.

[0003] Laser cladding technology, as a highly efficient surface coating technique, has been widely used in brake disc repair. Laser cladding not only significantly improves the bonding strength of the coating material but also enhances the wear resistance of the coating while maintaining the mechanical properties of the substrate. However, currently available laser cladding alloys struggle to achieve sufficient thermal fatigue resistance when used for brake disc repair. Summary of the Invention

[0004] In view of this, the technical problem to be solved by this application is to provide an alloy powder, its preparation method, a brake disc and its repair method. When the alloy powder provided by this application is used to repair the coating of the brake disc, it can significantly improve the hardness, wear resistance and thermal fatigue resistance of the coating.

[0005] This application provides an alloy powder, comprising:

[0006] 0.1wt%~2.0wt% Cr;

[0007] 0.5wt%~3.0wt% Ni;

[0008] 0.1wt%~1wt% Mo;

[0009] 0.1wt%~1.5wt% Mn;

[0010] 0.01wt%~1.5wt% Si;

[0011] 0.01wt%~1.0wt% C;

[0012] 0~2.0wt% V;

[0013] 0~5.0wt% Ti;

[0014] Balance Fe;

[0015] V and Ti are not both 0.

[0016] In some specific implementations, the alloy powder includes:

[0017] 0.1wt%~2.0wt% Cr;

[0018] 0.5wt%~3.0wt% Ni;

[0019] 0.1wt%~1wt% Mo;

[0020] 0.1wt%~1.5wt% Mn;

[0021] 0.01wt%~1.5wt% Si;

[0022] 0.01wt%~1.0wt% C;

[0023] 0.1wt%~2.0wt% V;

[0024] Balance of Fe.

[0025] In some specific implementations, the alloy powder includes:

[0026] 0.5wt%~1.5wt% Cr;

[0027] 1.0wt%~2.0wt% Ni;

[0028] 0.2wt%~0.5wt% Mo;

[0029] 0.5wt%~1.0wt% Mn;

[0030] 0.1wt%~0.5wt% Si;

[0031] 0.1wt%~0.3wt% C;

[0032] 0.5wt%~2wt% V;

[0033] Balance of Fe.

[0034] In some specific implementations, the alloy powder includes:

[0035] 0.8wt%~1.2wt% Cr;

[0036] 1.2wt%~1.8wt% Ni;

[0037] 0.4wt%~0.5wt% Mo;

[0038] 0.6wt%~0.8wt% Mn;

[0039] 0.2wt%~0.4wt% Si;

[0040] 0.2wt%~0.3wt% C;

[0041] 0.5wt%~2.0wt% V;

[0042] Balance of Fe.

[0043] This application also provides a brake disc, including a substrate and a coating formed on the substrate, the coating being formed from the alloy powder described in the above-described technical solutions.

[0044] In some specific implementations, the substrate includes:

[0045] 0.1wt%~2.0wt% Cr;

[0046] 0.5wt%~3.0wt% Ni;

[0047] 0.1wt%~1wt% Mo;

[0048] 0.1wt%~1.5wt% Mn;

[0049] 0.01wt%~1.5wt% Si;

[0050] 0.01wt%~1.0wt% C;

[0051] Balance of Fe.

[0052] This application also provides a method for preparing alloy powder, comprising the following steps:

[0053] Cr powder, Ni powder, Mo powder, Mn powder, Si powder, C powder, Fe powder, V powder and Ti powder are mixed in the proportions described above to obtain a mixed powder;

[0054] The mixed powder is melted and formed into droplets under the action of aerosol, and then cooled to obtain alloy powder.

[0055] In some specific implementations, the mixing speed is 50~100 rpm; the mixing time is 1h~3h.

[0056] This application also provides a method for repairing a brake disc, comprising the following steps:

[0057] The alloy powder described in the above technical solution is used to form a coating on the brake disc substrate by laser cladding.

[0058] In some specific implementations, the parameters of the laser cladding are:

[0059] Laser power 3600W~4000W; scanning speed 12mm / s~16mm / s; laser spot diameter 3.2mm~4.0mm; powder feeding rate 16g / min~22g / min; argon flow rate 20L / min~25L / min; overlap rate 30%~50%.

[0060] The alloy powder provided in this application comprises: 0.1wt%~2.0wt% Cr; 0.5wt%~3.0wt% Ni; 0.1wt%~1wt% Mo; 0.1wt%~1.5wt% Mn; 0.01wt%~1.5wt% Si; 0.01wt%~1.0wt% C; 0~2.0wt% V; 0~5.0wt% Ti; and the balance Fe; V and Ti are not both 0. This application adds V and / or Ti, especially V, to the alloy powder, giving it high specific strength, excellent wear resistance, and thermal fatigue resistance. When used as a repair coating, it can significantly improve the bonding strength of the coating material, enhancing the wear resistance and thermal fatigue resistance of the coating while maintaining the mechanical properties of the substrate. This effectively improves the overall performance of the substrate, such as a steel-based brake disc, meeting the braking requirements of high-speed trains traveling at 350 km / h. Attached Figure Description

[0061] Figure 1 This is a morphology image of the alloy powder prepared in Example 4 of this application;

[0062] Figure 2 A schematic diagram illustrating laser cladding repair of the brake disc in an embodiment of this application;

[0063] Figure 3 This is a schematic diagram of brake disc partitioning provided in an embodiment of this application;

[0064] Figure 4 Actual photos of the brake disc being repaired;

[0065] Figure 5 The surface morphology of the coating and bonding surface provided in Embodiment 6 of this application;

[0066] Figure 6 Microstructure diagram of the coating and substrate provided in Example 6 of this application;

[0067] Figure 7 The mechanical property test results of the coating provided in Example 6 of this application;

[0068] Figure 8 Image of the tensile fracture surface of the coating;

[0069] Figure 9Crack morphology of the coating and substrate provided in the embodiments of this application after 1000 cycles of thermal fatigue;

[0070] Figure 10 The wear amount and coefficient of friction of the coating provided in the embodiments of this application;

[0071] Figure 11 Scanning electron microscope (SEM) images of the coatings prepared for embodiments of this application;

[0072] Figure 12 This is a schematic diagram of a non-zoned brake disc provided in Example 11;

[0073] Figure 13 This is a schematic diagram of the brake disc partitioning provided in Example 12;

[0074] Figure 14 This is a schematic diagram of the brake disc partition provided in Example 13;

[0075] Figure 15 This is a schematic diagram of the brake disc partition provided in Example 14. Detailed Implementation

[0076] This invention provides an alloy powder, its preparation method, a brake disc, and its repair method. Those skilled in the art can refer to the content of this document and appropriately modify the process parameters to achieve the desired results. The methods and applications of this invention have been described through preferred embodiments. Those skilled in the art can obviously make modifications or appropriate alterations and combinations to the methods and applications described herein without departing from the content, spirit, and scope of this invention to realize and apply the technology of this invention.

[0077] This application provides an alloy powder, comprising:

[0078] 0.1wt%~2.0wt% Cr;

[0079] 0.5wt%~3.0wt% Ni;

[0080] 0.1wt%~1.0wt% Mo;

[0081] 0.1wt%~1.5wt% Mn;

[0082] 0.01wt%~1.5wt% Si;

[0083] 0.01wt%~1.0wt% C;

[0084] 0~2.0wt% V;

[0085] 0~5.0wt% Ti;

[0086] Balance Fe;

[0087] V and Ti are not both 0.

[0088] The alloy powder provided in this application includes Cr, which can improve the corrosion resistance and mechanical properties of the alloy. In some specific implementations, the Cr content is 0.1wt% to 2.0wt%, preferably 0.5wt% to 1.5wt%, more preferably 0.8wt% to 1.2wt%, for example, it can be 0.1wt%, 0.5wt%, 0.8wt%, 1.0wt%, 1.2wt%, 1.5wt%, 2.0wt%, etc.

[0089] The alloy powder provided in this application includes Ni, which can improve the corrosion resistance and mechanical properties of the alloy. In some specific implementations, the Ni content is 0.5wt% to 3.0wt%, preferably 1.0wt% to 2.0wt%, more preferably 1.2wt% to 1.8wt%, for example, it can be 0.5wt%, 1.0wt%, 1.2wt%, 1.5wt%, 1.8wt%, 2.0wt%, 3.0wt%, etc.

[0090] The alloy powder provided in this application includes Mo, which can improve the high-temperature strength of the alloy, enhance its hardenability, strengthen its corrosion resistance, and refine its grain size. In some specific implementations, the Mo content is 0.1wt% to 1.0wt%, preferably 0.2wt% to 0.5wt%, more preferably 0.4wt% to 0.5wt%, for example, it can be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.8wt%, 1.0wt%, etc.

[0091] The alloy powder provided in this application includes Mn, which can strengthen the alloy matrix and improve its processing performance. In some specific implementations, the Mn content is 0.1wt% to 1.5wt%, preferably 0.5wt% to 1.0wt%, more preferably 0.6wt% to 0.8wt%, for example, it can be 0.1wt%, 0.5wt%, 0.6wt%, 0.8wt%, 1.0wt%, 1.2wt%, 1.5wt%, etc.

[0092] The alloy powder provided in this application includes Si, which can enhance the mechanical properties of the alloy. In some specific implementations, the Si content is 0.01wt% to 1.5wt%, preferably 0.1wt% to 0.5wt%, more preferably 0.2wt% to 0.4wt%, for example, it can be 0.01wt%, 0.05wt%, 0.1wt%, 0.2wt%, 0.4wt%, 0.5wt%, 1.5wt%, etc.

[0093] The alloy powder provided in this application includes carbon (C), which can improve the strength and hardness of the alloy. In some specific implementations, the C content is 0.01wt% to 1.0wt%, preferably 0.1wt% to 0.3wt%, more preferably 0.2wt% to 0.3wt%, and for example, it can be 0.01wt%, 0.05wt%, 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 1.0wt%, etc.

[0094] The alloy powder provided in this application includes V, which can improve the wear resistance, strength, and thermal fatigue resistance of the alloy. In some specific implementations, the V content is 0~2.0wt%, preferably 0.1wt%~2.0wt%, more preferably 0.5wt%~2.0wt%, for example, it can be 0.1wt%, 0.2wt%, 0.5wt%, 1.0wt%, 1.5wt%, 2.0wt%, etc.

[0095] The alloy powder provided in this application includes Ti, which can improve the wear resistance, strength, and thermal fatigue resistance of the alloy. In some specific implementations, the Ti content is 0 wt% to 5.0 wt%, preferably 1.0 wt% to 2.0 wt%, for example, it can be 1.0 wt%, 1.5 wt%, 2.0 wt%, 5.0 wt%, etc.

[0096] In the alloy powder provided in this application, the contents of Ti and V are not both 0, but V is preferred. Compared with Ti, a small amount of V can achieve the same effect as Ti.

[0097] The alloy powder provided in this application includes Fe, with Fe making up 100%.

[0098] In some specific implementations, the alloy powder includes:

[0099] 0.1wt%~2.0wt% Cr;

[0100] 0.5wt%~3.0wt% Ni;

[0101] 0.1wt%~1.0wt% Mo;

[0102] 0.1wt%~1.5wt% Mn;

[0103] 0.01wt%~1.5wt% Si;

[0104] 0.01wt%~1.0wt% C;

[0105] 0.1wt%~2.0wt% V;

[0106] Balance of Fe.

[0107] In some specific implementations, the alloy powder includes:

[0108] 0.5wt%~1.5wt% Cr;

[0109] 1.0wt%~2.0wt% Ni;

[0110] 0.2wt%~0.5wt% Mo;

[0111] 0.5wt%~1.0wt% Mn;

[0112] 0.1wt%~0.5wt% Si;

[0113] 0.1wt%~0.3wt% C;

[0114] 0.5wt%~2wt% V;

[0115] Balance of Fe.

[0116] In some specific implementations, the alloy powder includes:

[0117] 0.8wt%~1.2wt% Cr;

[0118] 1.2wt%~1.8wt% Ni;

[0119] 0.4wt%~0.5wt% Mo;

[0120] 0.6wt%~0.8wt% Mn;

[0121] 0.2wt%~0.4wt% Si;

[0122] 0.2wt%~0.3wt% C;

[0123] 0.5wt%~2.0wt% V;

[0124] Balance of Fe.

[0125] This application adds V and / or Ti, especially V, to alloy powder, giving the alloy powder high specific strength, excellent wear resistance and thermal fatigue resistance, which can significantly improve the bonding strength of coating materials. While maintaining the mechanical properties of the matrix, it enhances the wear resistance and thermal fatigue resistance of the coating when used as a repair coating, thereby effectively improving the overall performance of steel-based brake discs and meeting the braking requirements of high-speed trains with a speed of 350 km / h.

[0126] This application also provides a method for preparing alloy powder, comprising the following steps:

[0127] According to the proportions described in the above scheme, Cr powder, Ni powder, Mo powder, Mn powder, Si powder, C powder, Fe powder, V powder and Ti powder are mixed to obtain a mixed powder;

[0128] The mixed powder is melted and formed into droplets under the action of aerosol, and then cooled to obtain alloy powder.

[0129] This application uses corresponding raw material powders as raw materials, and first mixes them evenly, especially mixing V powder with other powders evenly to ensure the uniform distribution of V in the alloy. Specifically, this application can mix the raw materials evenly in a powder mixing device. In some specific implementations, the mixing speed is 50 rpm to 100 rpm, preferably 60 rpm to 80 rpm; the mixing time is 1 h to 3 h, preferably 1.5 h to 2.5 h.

[0130] After obtaining the mixed powder, it is melted, and then the molten mixed powder is formed into droplets under the action of aerosol. After cooling, alloy powder is obtained. Specifically, this application uses aerosolization to flow the molten alloy liquid through a guide nozzle, and then uses a high-speed jet of inert gas (such as argon) to break it into fine droplets. After the droplets are cooled in the atomization tower, they form spherical or near-spherical powder to obtain alloy powder.

[0131] This application also provides a brake disc, including a substrate and a coating formed on the substrate, the coating being formed from the alloy powder described in the above-described technical solutions.

[0132] The brake disc provided in this application includes a base, and in some specific implementations, the base includes:

[0133] 0.1wt%~2.0wt% Cr;

[0134] 0.5wt%~3.0wt% Ni;

[0135] 0.1wt%~1wt% Mo;

[0136] 0.1wt%~1.5wt% Mn;

[0137] 0.01wt%~1.5wt% Si;

[0138] 0.01wt%~1.0wt% C;

[0139] Balance of Fe.

[0140] This application describes a method for forming a coating on a substrate using the alloy powder described in the above-mentioned technical solution. This significantly improves the hardness, wear resistance, and thermal fatigue resistance of the brake disc, while also enhancing the bonding strength between the coating and the substrate. This extends the service life of the brake disc, reduces maintenance costs, and enables efficient, safe, and economical operation of the high-speed train braking system.

[0141] This application also provides a method for repairing a brake disc, comprising the following steps:

[0142] The alloy powder described in the above technical solution is used to form a coating on the brake disc substrate by laser cladding.

[0143] Specifically, this application involves fixing the brake disc to a worktable for laser cladding repair, see [link to relevant documentation]. Figure 2 The brake disc 21 to be repaired is fixed to the anti-deformation disc 23 by multiple bolts 22. The diameter of the anti-deformation disc 23 is the same as that of the brake disc, in order to ensure the amount of deformation after cladding. The worktable 24 is used to support the anti-deformation disc 23 and the brake disc 21 to be repaired, and the laser beam 25 is aimed at the area 26 to be repaired for repair.

[0144] In this application, when repairing the brake disc, the area to be repaired can be divided into eight equal areas and repaired in a specific order, such as... Figure 3 As shown, Figure 3 This is a schematic diagram of brake disc partitioning provided in an embodiment of this application. One region and its symmetrical region are designated as Region I; the two regions separated from Region I are designated as Region II; the region between Region I and Region II and its symmetrical region are designated as Region III; and the remaining region is designated as Region IV. Laser cladding is performed in the order of Region I, Region II, Region III, and Region IV. Alternatively, the brake disc can be unpartitioned, such as... Figure 12 As shown, laser cladding can be performed sequentially; alternatively, the brake disc can be divided into four equal zones, with any two symmetrical zones designated as Zone I and the other two as Zone II, as shown below. Figure 13 As shown, laser cladding can be performed in the order of Zone I and Zone II; alternatively, the brake disc can be divided into 6 equal zones, with any two symmetrical zones designated as Zone I, any adjacent zone and its symmetrical zone designated as Zone II, and the remaining zones designated as Zone III, as shown below. Figure 14 As shown, laser cladding can be performed in the order of Zone I, Zone II, and Zone III. The brake disc can also be divided into 18 equal zones. Any two symmetrical zones are designated as Zone I. Starting from any Zone I, zones are numbered sequentially in a clockwise direction as Zones VIII, VI, IV, II, III, V, VII, and IX. Figure 15 As shown, laser cladding can be performed in the order of Zone I, Zone II, Zone III to Zone IX.

[0145] In one specific implementation, prior to laser cladding, the alloy powder and the substrate are preferably pretreated:

[0146] Dry the alloy powder;

[0147] The substrate is surface treated and then heated and kept warm.

[0148] Specifically, this application pre-treats the alloy powder in a drying oven at a temperature of 80°C to 120°C, preferably 90°C to 110°C, and more preferably 100°C. The purpose of the pre-treatment is to reduce the moisture content of the alloy powder.

[0149] Specifically, this application performs surface treatment on the substrate to remove impurities from the substrate surface, preferably removing 0.5mm to 1.5mm from the brake disc surface, more preferably removing 1mm. Then, the substrate is heated and held at a temperature of 300℃ to 500℃, preferably 350℃ to 450℃, more preferably 400℃, and the holding time is preferably 1h to 3h, more preferably 1.5h to 2.5h, and most preferably 2h.

[0150] When forming a coating on a substrate using laser cladding, the parameters of the laser cladding are as follows:

[0151] The laser power is 3600W~4000W, preferably 3800W~4000W; the scanning speed is 12mm / s~16mm / s, preferably 12mm / s~14mm / s; the laser spot diameter is 3.2mm~4.0mm, preferably 3.4mm~3.8mm; the powder feeding rate is 16g / min~22g / min, preferably 18g / min~20g / min; the argon flow rate is 20L / min~25L / min, preferably 22L / min~24L / min; and the overlap rate is 30%~50%, preferably 35%~45%.

[0152] After laser cladding is completed, the resulting material is subjected to heat preservation treatment. In some specific implementations, the heat preservation temperature is preferably 300℃~600℃, more preferably 400℃~500℃, and even more preferably 450℃; the heat preservation time is preferably more than 5 hours, and even more preferably 5 hours~10 hours.

[0153] After the heat insulation treatment is completed, the coating surface is processed to ensure that the surface roughness is less than Ra0.8, and the brake disc can be obtained.

[0154] The brake disc provided in this application has high strength, excellent wear resistance and thermal fatigue resistance, and can meet the braking requirements of high-speed trains with a speed of 350 km / h.

[0155] The following examples further illustrate the alloy powder for repairing steel-based brake discs and its preparation method provided in this application.

[0156] Examples 1-5

[0157] Prepare alloy powders according to the formulations shown in Table 1:

[0158] Table 1 Alloy powder formulations for Examples 1-5

[0159]

[0160] Alloy powder was prepared according to the following method: Metal powders were mixed in a mixing device at a speed of 72 r / min for 2 hours according to the proportions shown in Table 1, ensuring uniform distribution of the metal powders, especially V powder. The mixed powder was then melted to obtain a molten alloy liquid. This molten alloy liquid was atomized through a nozzle and then broken into fine droplets by a high-speed jet of inert gas (argon). The droplets cooled in the atomization tower to form spherical or near-spherical powder, thus obtaining the alloy powder. The alloy powder prepared in Example 4 was observed; the results are shown in [reference needed]. Figure 1 , Figure 1 These are morphology images of the alloy powder prepared in Example 4 of this application, where (a) is a morphology image under low magnification and (b) is a morphology image under high magnification. Figure 1 As can be seen, the alloy powder prepared in the embodiments of this application has a regular morphology, mainly spherical, and the particle size is relatively uniform.

[0161] Example 6

[0162] A brake disc with the composition shown in Comparative Example 1 is provided, and the brake disc is fixed on a worktable for laser cladding. See [link to relevant documentation]. Figure 2 , Figure 2 This is a schematic diagram of laser cladding repair of a brake disc according to an embodiment of this application. The brake disc 21 to be repaired is fixed to the anti-deformation disc 23 by multiple bolts 22. The diameter of the anti-deformation disc 23 is the same as that of the brake disc, and the thickness is 80mm, in order to ensure the amount of deformation after cladding. The worktable 24 is used to support the anti-deformation disc 23 and the brake disc 21 to be repaired, and the laser beam 25 is aimed at the area 26 to be repaired for repair.

[0163] The specific process is as follows:

[0164] The alloy powder prepared in Example 4 was placed in a drying oven and dried in a vacuum environment at 100°C for 4 hours to remove moisture from the powder.

[0165] Before laser cladding repair of the brake disc, 1mm of the surface of the brake disc is removed, and the treated brake disc is placed in a heating furnace and preheated to 400℃ and kept at that temperature for 2 hours.

[0166] Laser cladding was performed on the brake disc surface under the following conditions: an overlap rate of 40% for each cladding layer, a laser power of 4000W, a scanning speed of 12mm / s, a laser spot diameter of 3.6mm, a powder feed rate of 20g / min, and an argon flow rate of 23L / min. During laser cladding, the area to be repaired on the brake disc was divided into 8 equal regions, such as... Figure 3 As shown, Figure 3 The schematic diagram of brake disc partitioning provided in this application embodiment is as follows: one region and its symmetrical region are referred to as region I, the two regions separated from region I are referred to as region II, the region between region I and region II and its symmetrical region are referred to as region III, and the remaining region is referred to as region IV. Laser cladding is performed in the order of region I, region II, region III and region IV.

[0167] After the repair is completed, the brake disc and the anti-deformation disc are kept at 450℃ for at least 5 hours; then the anti-deformation disc is removed, and the brake disc is surface-machined to ensure that the surface roughness is less than Ra0.8, forming a coating.

[0168] The brake disc coating prepared in Example 6 was observed, and the results are shown in [reference needed]. Figure 4 , Figure 5 and Figure 6 , Figure 4 The images show actual photographs of the brake disc during the repair process, with (a) being a photograph of the brake disc during the repair process and (b) being a photograph of the brake disc after the coating has been applied. Figure 5 The surface morphology of the coating and bonding surface provided in Embodiment 6 of this application is shown in (a) as the surface morphology of the coating and (b) as the surface morphology of the cross section of the coating bonded to the substrate. Figure 6 These are microstructure images of the coating and substrate provided in Embodiment 6 of this application, wherein (a) is the microstructure of the coating, and (b) is the microstructure of the substrate. Figure 4 , Figure 5 and Figure 6 It is known that the repair coating prepared in the embodiments of this application has no defects such as cracks and pores, and the coating microstructure is mainly composed of fine lath martensite.

[0169] The tensile properties of the coating and substrate were tested separately, and the shear properties of the coating, substrate, and bonding zone were also tested. The results are shown in [reference needed]. Figure 7 and Figure 8 , Figure 7 The mechanical property test results of the coating provided in Example 6 of this application are shown in (a) as the tensile curve and (b) as the micro-shear strength in different regions. Figure 8 This is a tensile fracture morphology diagram of the coating. (From...) Figure 6 and Figure 7 It is evident that the coating provided in this application improves the shear strength of the substrate.

[0170] The thermal fatigue properties of the coating and the substrate were tested separately, and the results are shown in [reference]. Figure 9 , Figure 9 The images show the crack morphology of the coating and substrate after 1000 cycles of thermal fatigue, as provided in the embodiments of this application. (a) shows the thermal fatigue crack morphology of the coating, and (b) shows the thermal fatigue crack morphology of the substrate. Figure 9 It is understood that the coating provided in this application improves the thermal fatigue performance of the substrate.

[0171] The wear and friction coefficients of the coating and substrate were tested separately, and the results are shown in [reference needed]. Figure 10 , Figure 10 The wear amount and friction coefficient of the coating provided in the embodiments of this application are shown, (a) is the wear loss amount, and (b) is the friction coefficient. Figure 10 It is evident that the coating provided in this application exhibits a low wear rate.

[0172] Examples 7-10

[0173] Following the same method as in Example 6, the alloy powder was replaced with the alloy powder prepared in Examples 1, 2, 3, and 5, respectively, to perform laser cladding repair on the brake disc. The results are shown in [reference needed]. Figure 11 , Figure 11 Scanning electron microscope (SEM) images of the coatings prepared in the embodiments of this application: (a) is an image of the coating prepared in Example 1, (b) is an image of the coating prepared in Example 2, (c) is an image of the coating prepared in Example 3, and (d) is an image of the coating prepared in Example 5.

[0174] The coatings prepared in Examples 6 to 10 were subjected to performance tests, and the results are shown in Table 2. Table 2 shows the performance test results of the coatings provided in the examples of this application.

[0175] Table 2 Performance test results of the coatings provided in the embodiments of this application

[0176]

[0177] The tensile strength was tested using the following method: A universal testing machine was used to process the repair coating material into tensile specimens, and the two ends of the specimens were clamped in the upper and lower jaws of the universal testing machine. The testing machine applied an axial tensile force at a constant rate of 1 mm / min until the specimen broke. The maximum load (Fm) / the original cross-sectional area of ​​the specimen (S0) was calculated from the load-displacement curve automatically recorded by the instrument throughout the process.

[0178] The yield strength was tested as follows: A universal testing machine was used. The repair coating material was processed into a tensile specimen, and both ends of the specimen were clamped in the upper and lower jaws of the universal testing machine. The testing machine applied an axial tensile force at a constant rate of 1 mm / min until the specimen broke. The load-displacement curves throughout the process were automatically recorded by the instrument. The stress at which 0.2% plastic strain was produced was calculated as the conditional yield strength (Rp0.2). This was determined by plotting the load-displacement curve using the "parallel line method".

[0179] The elongation was tested as follows: A universal testing machine was used to process the repair coating material into tensile specimens. The specimens were clamped at both ends in the upper and lower jaws of the universal testing machine. The machine applied an axial tensile force at a constant rate of 1 mm / min until the specimen broke. The load-displacement curves throughout the process were automatically recorded by the instrument, and the result was calculated as (gauge length after fracture (Lu) - original gauge length (L0)) / original gauge length (L0) × 100%.

[0180] Wear was tested using the following method: A pin-disc sliding wear test was conducted. A standard-sized pin sample (friction pair) was pressed onto a rotating disk (coating repair material) with a load of 20 N. After 2 hours, the wear was measured. The wear was calculated as the sample's mass before the test minus its mass after the test.

[0181] Hardness was tested using the following method: A micro Vickers hardness tester was used to test the hardness of the repair coating. A diamond indenter with a 136° angle between opposing faces was pressed into the sample. After holding the indentation, the diagonal length of the indentation was measured to calculate the hardness value. Test parameters were: test force 9.8 N, holding time 15 s, and interval between test points greater than 0.1 mm.

[0182] Shear strength was tested as follows: Using a universal testing machine, the specimen was placed in a shear fixture, ensuring the blade was aligned with the specimen's contact line. Pressure was applied to the fixture on the universal testing machine until the specimen was sheared. The load-displacement curve was automatically recorded throughout the process, and the shear strength was calculated as the maximum shear load (F) / shear cross-sectional area (A).

[0183] The 1000-cycle thermal fatigue crack test was conducted as follows: The repair coating was processed into a thermal fatigue specimen to be tested. The specimen was placed in a thermal fatigue testing machine, and its surface was heated to 600°C in a very short time by induction heating, held at that temperature for 250 seconds, and then immediately subjected to forced water cooling to lower it to the target low temperature of 25°C in a very short time, held at that temperature for 15 seconds. This "heating-cooling" process constituted one cycle. Every 100 cycles, the specimen was removed and the length of the longest crack was measured using a metallographic microscope.

[0184] As shown in Table 2, the coating prepared in the embodiments of this application has excellent comprehensive mechanical properties and can be used as a repair material for brake discs.

[0185] Example 11

[0186] The difference from Example 6 is that, during laser cladding, the brake disc is not divided into sections, such as... Figure 12 As shown, Figure 12 The diagram below shows the brake disc without partitions provided in Example 11. Laser cladding can be performed in sequence.

[0187] Example 12

[0188] The difference from Example 6 is that during laser cladding, the brake disc is divided into four equal zones, with any two symmetrical zones designated as Zone I and the other two zones designated as Zone II, such as... Figure 13 As shown, Figure 13 The diagram shows the brake disc partitioning provided in Example 12. Laser cladding can be performed in the order of Zone I and Zone II.

[0189] Example 13

[0190] The difference from Example 6 is that during laser cladding, the brake disc is divided into six equal zones. Any two symmetrical zones are designated as Zone I, any adjacent zone and its symmetrical zone are designated as Zone II, and the remaining zones are designated as Zone III. Figure 14 As shown, Figure 14 The diagram shows the brake disc partitioning provided in Example 13. Laser cladding can be performed in the order of Zone I, Zone II, and Zone III.

[0191] Example 14

[0192] The difference from Example 6 is that during laser cladding, the brake disc is divided into 18 equal zones. Any two symmetrical zones are designated as Zone I, and starting from any Zone I, zones VIII, VI, IV, II, III, V, VII, and IX are sequentially numbered clockwise. Figure 15 As shown, Figure 15 The diagram shows the brake disc partitioning provided in Example 14. Laser cladding can be performed in the order of Zone I, Zone II, Zone III to Zone IX.

[0193] The test results for different laser cladding methods are calculated and shown in Table 3. Table 3 shows the test results for different cladding methods.

[0194] Table 3 Test results for different cladding methods

[0195]

[0196] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications 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. An alloy powder, characterized in that, include: 0.1wt%~2.0wt% Cr; 0.5wt%~3.0wt% Ni; 0.1wt%~1wt% Mo; 0.1wt%~1.5wt% Mn; 0.01wt%~1.5wt% Si; 0.01wt%~1.0wt% C; 0~2.0wt% V; 0~5.0wt% Ti; Balance Fe; V and Ti are not both 0.

2. The alloy powder according to claim 1, characterized in that, include: 0.1wt%~2.0wt% Cr; 0.5wt%~3.0wt% Ni; 0.1wt%~1wt% Mo; 0.1wt%~1.5wt% Mn; 0.01wt%~1.5wt% Si; 0.01wt%~1.0wt% C; 0.1wt%~2.0wt% V; Balance of Fe.

3. The alloy powder according to claim 2, characterized in that, include: 0.5wt%~1.5wt% Cr; 1.0wt%~2.0wt% Ni; 0.2wt%~0.5wt% Mo; 0.5wt%~1.0wt% Mn; 0.1wt%~0.5wt% Si; 0.1wt%~0.3wt% C; 0.5wt%~2wt% V; Balance of Fe.

4. The alloy powder according to claim 3, characterized in that, include: 0.8wt%~1.2wt% Cr; 1.2wt%~1.8wt% Ni; 0.4wt%~0.5wt% Mo; 0.6wt%~0.8wt% Mn; 0.2wt%~0.4wt% Si; 0.2wt%~0.3wt% C; 0.5wt%~2.0wt% V; Balance of Fe.

5. A brake disc comprising a substrate and a coating formed on the substrate, the coating being formed from the alloy powder according to any one of claims 1 to 4.

6. The brake disc according to claim 5, characterized in that, The matrix includes: 0.1wt%~2.0wt% Cr; 0.5wt%~3.0wt% Ni; 0.1wt%~1wt% Mo; 0.1wt%~1.5wt% Mn; 0.01wt%~1.5wt% Si; 0.01wt%~1.0wt% C; Balance of Fe.

7. A method for preparing the alloy powder according to any one of claims 1 to 4, comprising the following steps: According to the alloy powder formulation of any one of claims 1 to 4, Cr powder, Ni powder, Mo powder, Mn powder, Si powder, C powder, Fe powder, V powder and Ti powder are mixed to obtain a mixed powder; The mixed powder is melted and formed into droplets under the action of aerosol, and then cooled to obtain alloy powder.

8. The preparation method according to claim 7, characterized in that, The mixing speed is 50-100 rpm; the mixing time is 1-3 hours.

9. A method for repairing a brake disc, comprising the following steps: The alloy powder described in any one of claims 1 to 4 is used to form a coating on the brake disc substrate by laser cladding.

10. The repair method according to claim 9, characterized in that, The parameters of the laser cladding are: Laser power 3600W~4000W; scanning speed 12mm / s~16mm / s; laser spot diameter 3.2mm~4.0mm; powder feeding rate 16g / min~22g / min; argon flow rate 20L / min~25L / min; overlap rate 30%~50%.

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