Large equipment rack surface laser cladding powder, preparation and path planning method

Abstract

The application discloses a kind of large equipment rack surface laser cladding powder, preparation and path planning method, belong to laser cladding technical field.The powder is iron-based alloy powder, by C, B, Si, Mn, Cr, Mo, Ni, Fe according to certain mass percentage, powder is spherical or near spherical, particle size 53~150 μm, fluidity 14~17 s / 50g, loose density 3.8~5.0g / cm 3 ;Preparation method includes vacuum induction melting, gas atomization powder, screening and drying;Path planning method includes obtaining 3D model, functional area division, curvature adaptive variable speed scanning, differential lap rule and equipment travel limited time's partition splicing strategy.The application is by the cooperation of powder formula-preparation process-path planning, forms hardness 40~60HRC, no crack, and substrate metallurgical bonding cladding layer on straightening machine rack surface, is suitable for high quality laser cladding strengthening of special-shaped surface.

Description

Technical Field

[0001] This invention relates to the field of laser cladding technology, and in particular to a laser cladding powder for the surface of a large equipment frame, its preparation, and a path planning method. Background Technology

[0002] In the coal mining and metallurgical industry, coal mining equipment such as mine hoist frames, scraper conveyor troughs, and crusher bases, as well as metallurgical equipment such as rolling mill stands, continuous casting machine sector frames, and straightening machine frames, are subjected to harsh conditions of high-load impact, alternating stress, and abrasive wear for extended periods. Similarly, in the machinery manufacturing sector, key structural components such as large press bodies, forging press bases, and injection molding machine templates face similar challenges. The working surfaces of these devices (such as guide rail surfaces, mounting mating surfaces, guide slides, and bearing seat mating surfaces) are highly susceptible to wear pits, indentations, fatigue micro-cracks, and localized plastic deformation, leading to loss of overall machine installation accuracy, increased operational vibration, and in severe cases, even equipment safety accidents. Traditional repair methods often involve welding followed by machining or replacing the entire part with a new one. However, welding involves a large heat input and a wide heat-affected zone, which can easily cause thermal deformation of the frame and harmful residual stress. Furthermore, subsequent machining cycles are long and materials are wasted. Replacing the entire part is costly and results in huge production losses. These methods are no longer able to meet the urgent needs of modern coal mining, metallurgy, and machinery manufacturing industries for rapid, economical, and green equipment repair.

[0003] Laser cladding technology can form a metallurgically bonded coating on the substrate surface with a low dilution rate, significantly improving wear resistance and fatigue resistance. However, existing technologies still have many shortcomings: First, in terms of powder materials, general cladding powders have poor thermophysical compatibility with the substrate of large equipment frames (usually low-carbon steel or low-alloy steel), making the cladding layer prone to cracks and pores; second, in terms of powder preparation, traditional mechanically mixed powders suffer from defects such as component segregation and poor flowability; third, in terms of path planning, for the large-area irregularly shaped surfaces of large equipment frames, manual teaching programming is inefficient and inaccurate, making it difficult to ensure the uniformity and overlap quality of the cladding layer. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing laser cladding powder and path planning for the surface of large equipment racks, which solves the problems of wear, indentation and local deformation failure caused by high load impact, cyclic stress and abrasive wear during long-term service of large equipment racks, and realizes high-quality laser cladding strengthening and repair of rack surfaces.

[0005] To achieve the above objectives, the present invention provides a laser cladding powder for the surface of a large equipment frame. The powder is an iron-based alloy powder with the following elemental mass percentage composition: C: 0.15~0.22%, B: 0.01~0.03%, Si: 0.8~1.2%, Mn: 0.1~0.5%, Cr: 16.0~25.0%, Mo: 1.5~2.2%, Ni: 3.5~4.8%, with the balance being Fe. The powder particles are spherical or nearly spherical in shape, with a particle size range of 53~150μm; The powder has a flowability of 14s / 50g to 17s / 50g and a loose packing density of 3.8g / cm³. 3 ~5.0g / cm 3 .

[0006] Preferably, the hardness of the cladding layer formed by laser cladding of the powder is 40HRC~60HRC, the cladding layer forms a metallurgical bond with the large equipment frame substrate, and the cladding layer is free of cracks and pores.

[0007] This invention also provides a method for preparing the laser cladding powder on the surface of the above-mentioned large equipment frame, comprising the following steps: S1. Weigh each component raw material according to the set mass percentage, and melt them evenly in a vacuum induction melting furnace at 1500~1700℃ to obtain molten alloy liquid; S2. The molten alloy liquid is introduced into the atomization chamber, the reinforcing particles are mixed with high-pressure inert gas to form a gas-powder mixture and sprayed out. The gas flow generated when the gas-powder mixture is sprayed out is used to atomize the molten alloy liquid. The atomization pressure is controlled at 2~8MPa to obtain alloy powder. S3. Cool and sieve the atomized alloy powder, retaining the powder portion with a particle size of 53μm~150μm; S4. Dry the sieved powder at 100℃~150℃ for 1 hour to 3 hours, and then seal and package it.

[0008] Preferably, in S1, the melting temperature is 1600℃~1700℃; in S2, the atomization pressure is 4MPa~6MPa; and the high-pressure inert gas is high-purity argon with a purity of 99.99%.

[0009] This invention also provides a path planning method for laser cladding on the surface of large equipment frames. The path planning method for laser cladding on the surface of large equipment frames using the powder includes the following steps: T1. Obtain a 3D model of the surface to be processed on the frame of a large equipment; T2. Slice the 3D model to divide the surface to be processed into multiple functional areas, set cladding parameters for each functional area and generate corresponding G-code path segments for each area. T3. Extract each path point of the machining trajectory in the G code, calculate the curvature value of each path point, and adaptively adjust the scanning speed and powder feed amount according to the curvature. T4. The Delaunay triangulation algorithm is used to plan the cladding path with equal overlap rate, and the overlap rules between different cladding passes are formulated for different regions. T5. Based on the actual travel range of the laser cladding equipment, divide the surface to be processed into multiple processable sub-regions and plan the overlapping sequence and scanning direction between the sub-regions; T6. Extract the position and attitude information of the robot end effector from the G-code file, embed the sub-region division results and scanning direction planning results into the robot path code generation module, generate the robot machining path code file, and import it into the robot for machining.

[0010] Preferably, in T2, the functional area includes: The central main bearing area is the area in the middle of the length direction of the surface to be processed, avoiding the steps at both ends; The stepped transition zone corresponds to the stepped segmented area along the length of the surface to be processed; End regions, corresponding to the edge regions at the left and right ends of the surface to be processed; The circular hole avoidance zone corresponds to the annular area around each circular hole on the surface to be processed. The rounded corner area corresponds to the corner region where each rounded corner is located on the surface to be processed.

[0011] Preferably, in T3, the specific method for adaptively adjusting the scanning speed and toner feed rate is as follows: Path segments with curvature exceeding a preset threshold are marked as low-speed scanning segments, and the scanning speed is reduced to 70%~80% of the normal value, and the powder feed rate is reduced to 80%~90% of the normal value; Path segments with curvature below a preset threshold maintain normal scanning speed and toner delivery.

[0012] Preferably, in T4, the overlapping rule is as follows: Overlap rate between passes: In the central main bearing area, the overlap rate of adjacent cladding passes is 40%~60%; in the stepped transition area, the overlap rate of adjacent cladding passes is 30%~50%; in the end area, the overlap rate of adjacent cladding passes is 40%~50%; in the round hole avoidance area, the overlap rate of adjacent cladding passes is 20%~40%; in the rounded corner area, the overlap rate gradually changes linearly from the outside to the inside according to the rounded corner arc length. Overlap direction: The central main bearing area and end area adopt unidirectional scanning along the length of the large equipment frame to enable directional grain growth; in the stepped transition area, the scanning direction is reciprocated at a 30° angle to the length of the large equipment frame to form a cross-network structure between adjacent passes; in the circular hole avoidance area, a concentric arc path is adopted around the circular hole, and the scanning direction is consistent with the tangent direction of the hole edge; in the rounded corner area, a radial scanning path is adopted. Interlayer overlap: During multi-layer cladding, the center line of the cladding channel of the next layer is offset by half the width of the first layer channel, so that the upper and lower cladding channels are staggered and the interlayer porosity is eliminated.

[0013] Preferably, in T5, the specific steps are as follows: T51. When the maximum travel of the equipment in the length direction of the surface to be processed is less than the total length of the surface to be processed, the surface to be processed is divided into several sub-regions along the length direction, and an overlapping area is set between adjacent sub-regions. T52. Within each sub-region, each functional area adopts a unidirectional scan along the length direction to ensure that the cladding layer grains grow in a directional manner, consistent with the direction of the principal compressive stress during the operation of large equipment. T53. Within the overlapping area, the scanning direction forms an angle of 30° to 45° with the scanning direction inside the sub-region. The scanning speed is reduced by 5% to 15% compared to the sub-region, the laser power is reduced by 5% to 20% compared to the sub-region, and the overlap rate between the cladding channels is 20% to 35%. The overlap width of the overlapping area is selected according to 3 to 5 times the equipment positioning error. T54. Planning the processing sequence between sub-regions: Adopting an alternating sequence strategy, that is, first process the odd-numbered layers of the first sub-region, then process the odd-numbered layers of the second sub-region, and then return to the even-numbered layers of the first sub-region, and so on; the scanning direction of adjacent sub-regions changes alternately between layers, that is, the first sub-region of the first layer is scanned along the length direction, and the second sub-region is scanned along the width direction; the two are interchanged in the next layer, so that the grain direction of the splicing interface is staggered. T55. When the equipment travel is limited and a splicing strategy of partition positioning and reference point reset is required, an additional tempering scan is added to the splicing area. The laser power of the tempering scan is reduced to 50% of the normal value, and the scanning speed is increased to 150% of the normal value.

[0014] This invention also provides a method for strengthening the surface of a large equipment frame using laser cladding, comprising the following steps: Pre-treatment of the surfaces to be processed on the frame of large equipment; The powder described above is used, and the powder is prepared by the preparation method described above; The processing path is generated using the path planning method described above; The powder is loaded into the powder feeder, and the laser cladding equipment is controlled to perform laser cladding on the surface to be processed on the large equipment frame according to the processing path to form a cladding layer.

[0015] Therefore, the present invention adopts the above-mentioned method for laser cladding powder, preparation and path planning on the surface of large equipment racks. Through the synergistic cooperation of powder formulation, preparation process and path planning, a complete technical chain is formed to ensure cladding quality at the material end, ensure powder supply at the process end and ensure processing accuracy at the method end. Together, it realizes high-quality laser cladding strengthening of large-area irregular surfaces of large equipment racks, which has significant industrial practical value.

[0016] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0017] Figure 1 This is a scanning electron microscope image of the special powder obtained in Example 1 of the present invention; Figure 2 This is a metallographic microstructure image of the cross-section of the cladding layer in Embodiment 2 of the present invention; Figure 3 This is a metallographic microstructure image of the cross-section of the cladding layer in Embodiment 3 of the present invention; Figure 4 This is a schematic diagram of the structure of the upper surface of the straightening machine frame according to an embodiment of the present invention; region A is the central main bearing area, region B is the stepped transition area, region C is the end area, region D is the circular hole avoidance area, and region E is the rounded corner area. Detailed Implementation

[0018] The technical solutions of the present invention will be further described below with reference to the accompanying drawings and embodiments. Unless otherwise defined, the technical or scientific terms used in this invention should be understood in their ordinary sense by those skilled in the art. The described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0019] Example 1: Powder preparation and characterization.

[0020] This embodiment provides a method for preparing laser cladding powder on the surface of a straightening machine frame. The specific process is as follows: S1. Weigh the raw materials according to the following mass percentages: C: 0.15~0.22%, B: 0.01~0.03%, Si: 0.8~1.2%, Mn: 0.1~0.5%, Cr: 16.0~25.0%, Mo: 1.5~2.2%, Ni: 3.5~4.8%, with the balance being Fe. Place the weighed raw materials in a vacuum induction melting furnace and melt them at 1650℃. During the melting process, high-purity argon gas with a purity of 99.99% is introduced as a protective atmosphere to ensure that the alloying elements are fully fused and the composition is uniform, resulting in a molten alloy liquid.

[0021] S2. Molten alloy liquid is introduced into the atomization chamber. Reinforcing particles are mixed with high-pressure inert gas to form a gas-powder mixture, which is then sprayed out. The gas flow generated during the spraying of the gas-powder mixture atomizes the molten alloy liquid. The atomizing gas is high-purity argon gas with a purity of 99.99%, and the atomization pressure is controlled at 5 MPa. The atomized droplets cool and solidify in the atomization chamber, forming alloy powder.

[0022] S3. Cool the atomized alloy powder and then sieve it through a standard sieve, retaining only the powder fraction with a particle size between 53μm and 150μm. Place the sieved powder in a vacuum drying oven and dry it at 120℃ for 2 hours, then seal and package it for later use.

[0023] The obtained powder was characterized. The powder morphology was observed using a scanning electron microscope, and the results are as follows: Figure 1 As shown. By Figure 1 It can be seen that the obtained powder particles are spherical or nearly spherical, with smooth surfaces, no obvious satellite particles or adhesion, and good sphericity. The powder flowability is 15.34 s / 50 g; the loose packing density is 4.55 g / cm³. 3 The above results indicate that the powder obtained in this embodiment has good flowability and loose packing density, meeting the requirements of laser coaxial powder feeding and cladding process for powder conveying stability.

[0024] Example 2: Performance test of single cladding layer.

[0025] This embodiment and subsequent embodiments use a straightening machine as an example for specific description. The iron-based alloy powder prepared in Example 1 is used to conduct a laser cladding experiment on the surface of the straightening machine frame to verify the microstructure and properties of the cladding layer.

[0026] Pre-treatment of the surface to be processed on the straightening machine frame: Use an angle grinder to grind away the original wear layer and oxide layer until the metal luster is exposed. Then clean the ground surface with anhydrous ethanol and dry the area to be clad with dry air.

[0027] The dried powder is loaded into the powder feeder. The laser cladding equipment uses an RFL-C4000 high-power continuous fiber laser and is equipped with a six-axis industrial robot to control the movement trajectory of the laser cladding head. The laser cladding process parameters are set as follows: laser power 1800W, spot diameter 5mm, scanning speed 8mm / s, powder feeding rate 1.2r / min, overlap rate 50%, powder feeding gas flow rate 12L / min, and the protective gas is 99.99% pure argon gas with a flow rate of 15L / min.

[0028] The laser focus is adjusted to the surface to be processed on the straightening machine frame. The laser cladding head is controlled by a six-axis industrial robot to move along a preset path to complete the laser cladding operation on the surface of the straightening machine frame, forming a cladding layer with a thickness of about 0.8 mm. After the cladding is completed, it is naturally cooled to room temperature.

[0029] Metallographic samples were prepared from the cladding area, and the microstructure of the cross-section of the cladding layer was observed using a metallographic microscope. The results are as follows: Figure 2 As shown. By Figure 2 It can be seen that the cladding layer has a uniform and dense structure, without macroscopic cracks or pores, and the overlap transition is smooth, forming a good metallurgical bonding interface with the substrate, with no obvious defects at the interface. The surface hardness of the cladding layer was tested using a Rockwell hardness tester, and the results showed that the average hardness of the cladding layer was 46.8 HRC, which meets the surface hardness requirements of the straightening machine frame.

[0030] Example 3: Cladding performance under different process parameters.

[0031] This embodiment uses the same powder formulation and preparation method as Example 1, only adjusting the laser cladding process parameters to further verify the powder's process adaptability. Testing showed that the powder obtained in this embodiment has a flowability of 14.84 s / 50 g and a loose packing density of 3.95 g / cm³. 3 .

[0032] After performing the same pretreatment on the surface of the straightening machine frame as in Example 2, the following laser cladding process parameters were used: laser power 2000W, spot diameter 5mm, scanning speed 8mm / s, powder feeding rate 1.2r / min, overlap rate 30%, protective gas is argon, flow rate 15L / min.

[0033] After cladding, the material was allowed to cool naturally to room temperature, and then metallographic samples and performance tests were performed on the cladding layer. The results are as follows: Figure 3 As shown, the cladding layer has a dense structure, good interfacial bonding, and no cracks or pores were observed. The Rockwell hardness test result was 54.3 HRC, slightly higher than that of Example 2. The above results indicate that the powder of the present invention can achieve good cladding effects over a wide range of laser power and overlap rates, and has good process adaptability.

[0034] The performance test results of the powders obtained in Example 1 and Example 3 are summarized in Table 1.

[0035] Table 1 Summary of Powder Performance Test Results

[0036] Example 4: Laser cladding path planning for the surface of a straightening machine frame - standard stroke equipment.

[0037] This embodiment is based on Figure 4 The upper surface structure of the straightening machine frame shown in the figure provides a detailed explanation of the path planning method when using a standard stroke laser cladding device (with a stroke sufficient to cover the entire upper surface).

[0038] Figure 4 The overall dimensions and features of the upper surface of the straightening machine frame shown are as follows: overall length 4000mm, width 3820mm; the length direction is composed of end areas of 500mm at both ends and stepped segments in the middle of 225-750-150-750-150-750-225; the upper surface is provided with 4 circular holes with a diameter of 205mm and multiple R50 rounded corners.

[0039] T1. Obtain a 3D model of the surface to be processed on the straightening machine frame. Obtain a point cloud model of the upper surface of the frame through 3D scanning, and convert the point cloud model into an IGS format file. This 3D model accurately reflects... Figure 4 The geometry of the upper surface of the frame shown includes all the dimensional features described above.

[0040] T2. Slice the 3D model to divide the surface to be processed into the following functional areas: central main load-bearing area, such as... Figure 4 As shown in region A, the area corresponding to a length of 1500mm~2500mm (excluding the steps at both ends) and a width of 1000mm in the center has a smooth surface; the stepped transition area, as shown... Figure 4 As shown in region B, corresponding to the segments 225-750-150-750-150-750-225 along the length direction, the width varies with the steps; the end region, as... Figure 4 As shown in area C, the edge area is 500mm wide on both the left and right ends; the circular hole avoidance area, as shown in... Figure 4 As shown in region D, each A 10mm annular area around a 205mm round hole; rounded corner area, such as... Figure 4 As shown in region E, this is the corner area where the four R50 rounded corners are located. The cladding parameters are set for each functional area, and slicing is performed separately to generate the corresponding G-code path segments.

[0041] T3. Extract each path point of the machining trajectory from the G-code and calculate the curvature value of each path point. Mark the path segments with curvature higher than the preset threshold (such as the edge of a circular hole or a rounded corner) as low-speed scanning segments, and reduce the scanning speed to 70%~80% of the normal value and the toner feed to 80%~90% of the normal value accordingly; maintain the normal scanning speed and toner feed for path segments with curvature lower than the preset threshold (such as the straight section of the central main bearing area).

[0042] T4. The Delaunay triangulation algorithm is used to plan cladding paths with equal overlap rates, and overlap rules between cladding passes are established. Specifically: In the central main bearing area, the overlap rate of adjacent cladding passes is controlled at 40%~60%, and unidirectional scanning along the length of the rack is used to ensure directional grain growth; in the stepped transition area, due to the width change, the overlap rate is adjusted to 30%~50%, and the scanning direction is at a 30° angle to the length direction for reciprocating scanning, so that adjacent passes form a cross-network structure; in the end area, the overlap rate is 40%~50%, and unidirectional scanning along the length direction is used; in the circular hole avoidance area, a concentric arc path is planned around the circular hole, and the overlap rate of adjacent arc passes is 20%~40%, and the scanning direction is always consistent with the tangent direction of the hole edge; in the rounded corner area, a radial scanning path is used, and the overlap rate gradually changes linearly according to the rounded corner arc length, from 40% on the outside to 30% on the inside. For multi-layer cladding, the centerline of the cladding channel of the next layer is offset by half the width of the first layer, so that the upper and lower cladding channels are staggered, eliminating interlayer porosity. A 10mm wide overlap transition zone is set at the junction of the stepped transition zone and the central zone, and the overlap rate in the transition zone gradually changes linearly from 35% in the stepped zone to 45% in the central zone.

[0043] T5. Since the travel distance of the device in this embodiment is sufficient to cover the entire upper surface, sub-region segmentation is unnecessary. The position and attitude information of the robot's end effector are directly extracted from the G-code file to generate a robot machining path code file, which is then imported into the robot for machining.

[0044] Example 5: Laser cladding path planning on the surface of a straightening machine frame - travel-limited equipment.

[0045] This embodiment, based on the same upper surface structure of the straightening machine frame as in Embodiment 4, specifically describes the path planning method when the equipment stroke is limited (the maximum stroke in the X direction of the equipment is 2000mm, which is less than the total length of the upper surface of the frame of 4000mm).

[0046] T51. Obtain the working stroke of the laser cladding equipment. The maximum stroke in the X direction is 2000mm. Since the maximum stroke in the X direction is less than the total length of the upper surface of the frame (4000mm), the upper surface is divided into two sub-regions along its length: the first sub-region (0~2000mm) and the second sub-region (2000mm~4000mm), with a 15mm overlap between the two regions. Each sub-region contains a complete stepped segment; that is, the first sub-region covers the left end and part of the steps, and the second sub-region covers the right end and part of the steps.

[0047] T52. Within each sub-region, the central main bearing area, stepped transition area, end area, circular hole avoidance area, and rounded corner area all employ unidirectional scanning along the length direction to ensure the cladding layer grains grow in a directional manner, consistent with the direction of the principal compressive stress during the operation of the straightening machine. The overlap rate between cladding passes within the sub-region follows the rules in Example 4.

[0048] T53. Within the overlapping area, the scanning direction forms a 30°~45° angle with the scanning direction within the sub-region, causing the cladding layers of the two sub-regions to form a cross-network structure within the overlapping area, eliminating the weakening of the splicing interface caused by the consistent scanning direction. The scanning speed in the overlapping area is reduced by 5%~15% compared to the sub-region, and the laser power is reduced by 5%~20% to reduce thermal stress concentration. The overlap rate between cladding tracks within the overlapping area is 20%~35%. The overlap width of the overlapping area is selected as 3~5 times the equipment positioning error (±0.5mm) to ensure complete coverage of the splicing gap.

[0049] T54. The processing sequence between sub-regions is planned using an alternating sequence strategy. This involves processing the odd-numbered layers of the first sub-region first, then the odd-numbered layers of the second sub-region, and finally returning to the even-numbered layers of the first sub-region, repeating this cycle to avoid unilateral heat accumulation that could cause frame deformation. The scanning direction of adjacent sub-regions alternates between layers: in the first layer, the first sub-region is scanned along the length direction, and the second sub-region is scanned along the width direction; in subsequent layers, these directions are interchanged, causing the grain directions at the splicing interface to intersect.

[0050] T55. The sub-region division results and scanning direction planning results are embedded into the robot path code generation module, which automatically outputs a collision-free processing path that meets the equipment travel limit and imports it into the robot for processing.

[0051] Example 6: Splicing strategy when the stroke is severely limited.

[0052] This embodiment describes a splicing strategy that requires partitioned positioning and reference point reset when the equipment travel is severely limited (e.g., the maximum travel in the X direction is less than 1000mm).

[0053] When the equipment travel is severely limited, the upper surface of the straightening machine frame is divided into multiple sub-regions along its length (e.g., four sub-regions), and each sub-region is machined independently. After machining one sub-region, the laser cladding head is moved to the starting position of the next sub-region by resetting the reference point to continue machining.

[0054] Within each sub-region, the cladding path is planned according to the path planning method of Example 4. In the splicing area between adjacent sub-regions, in addition to setting an overlap area as in Example 5, after completing the cladding process for all sub-regions, a tempering scan is added to the splicing area. The laser power of the tempering scan is reduced to 50% of the normal value, and the scanning speed is increased to 150% of the normal value to eliminate residual stress at the splicing interface and improve the bonding quality of the splicing interface.

[0055] It should be noted that this invention is not limited to straightening machines, but can also be applied to the surface strengthening and repair of the frames of various large equipment, including but not limited to rolling mills, crushers, presses, forging presses, mining hoists and other heavy machinery, and has the versatility and scalability across equipment types.

[0056] Therefore, the present invention employs the above-mentioned method for preparing and planning laser cladding powder on the surface of large equipment frames, which can be widely applied to the surface strengthening and repair of large equipment frames in the fields of coal mining, metallurgy, and machinery manufacturing. The cladding layer prepared by the method of the present invention is dense, uniform, crack-free, and has moderate hardness, which can extend the service life of large equipment frames, reduce equipment maintenance costs, and has broad industrial application prospects.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the technical solutions of the present invention, and these modifications or equivalent substitutions cannot cause the modified technical solutions to deviate from the spirit and scope of the technical solutions of the present invention.

Claims

1. A laser cladding powder for the surface of a large equipment frame, characterized in that, The powder is an iron-based alloy powder, and the mass percentage composition of each element is as follows: C: 0.15~0.22%, B: 0.01~0.03%, Si: 0.8~1.2%, Mn: 0.1~0.5%, Cr: 16.0~25.0%, Mo: 1.5~2.2%, Ni: 3.5~4.8%, with the balance being Fe; The powder particles are spherical or nearly spherical in shape, with a particle size range of 53~150μm; The powder has a flowability of 14s / 50g to 17s / 50g and a loose packing density of 3.8g / cm³. 3 ~5.0g / cm 3 .

2. The laser cladding powder for the surface of a large equipment frame according to claim 1, characterized in that, The hardness of the cladding layer formed by the powder after laser cladding is 40HRC~60HRC. The cladding layer forms a metallurgical bond with the large equipment frame substrate, and the cladding layer is free of cracks and pores.

3. A method for preparing laser cladding powder on the surface of a large equipment frame as described in any one of claims 1 to 2, characterized in that, Includes the following steps: S1. Weigh each component raw material according to the set mass percentage, and melt them uniformly in a vacuum induction melting furnace at 1500~1700℃ to obtain molten alloy liquid; S2. The molten alloy liquid is introduced into the atomization chamber, the reinforcing particles are mixed with high-pressure inert gas to form a gas-powder mixture and sprayed out. The gas flow generated when the gas-powder mixture is sprayed out is used to atomize the molten alloy liquid. The atomization pressure is controlled at 2~8MPa to obtain alloy powder. S3. Cool and sieve the atomized alloy powder, retaining the powder portion with a particle size of 53μm~150μm; S4. Dry the sieved powder at 100℃~150℃ for 1 hour to 3 hours, and then seal and package it.

4. The preparation method according to claim 3, characterized in that, In S1, the melting temperature is 1600℃~1700℃; In S2, the atomization pressure is 4MPa~6MPa; the high-pressure inert gas is high-purity argon with a purity of 99.99%.

5. A path planning method for laser cladding on the surface of a large equipment frame, characterized in that, Path planning for laser cladding processing of the surface of a large equipment frame using the powder described in any one of claims 1 to 2 includes the following steps: T1. Obtain a 3D model of the surface to be processed on the frame of a large equipment; T2. Slice the 3D model to divide the surface to be processed into multiple functional areas, set cladding parameters for each functional area and generate corresponding G-code path segments for each area. T3. Extract each path point of the machining trajectory in the G code, calculate the curvature value of each path point, and adaptively adjust the scanning speed and powder feed amount according to the curvature. T4. The Delaunay triangulation algorithm is used to plan the cladding path with equal overlap rate, and the overlap rules between different cladding passes are formulated for different regions. T5. Based on the actual travel range of the laser cladding equipment, divide the surface to be processed into multiple processable sub-regions and plan the overlapping sequence and scanning direction between the sub-regions; T6. Extract the position and attitude information of the robot end effector from the G-code file, embed the sub-region division results and scanning direction planning results into the robot path code generation module, generate the robot machining path code file, and import it into the robot for machining.

6. The path planning method according to claim 5, characterized in that, In T2, the functional area includes: The central main bearing area is the area in the middle of the length direction of the surface to be processed, avoiding the steps at both ends; The stepped transition zone corresponds to the stepped segmented area along the length of the surface to be processed; End regions, corresponding to the edge regions at the left and right ends of the surface to be processed; The circular hole avoidance zone corresponds to the annular area around each circular hole on the surface to be processed. The rounded corner area corresponds to the corner region where each rounded corner is located on the surface to be processed.

7. The path planning method according to claim 5, characterized in that, In T3, the specific method for adaptively adjusting the scanning speed and toner feed rate is as follows: Path segments with curvature exceeding a preset threshold are marked as low-speed scanning segments, and the scanning speed is reduced to 70%~80% of the normal value, and the powder feed rate is reduced to 80%~90% of the normal value; Path segments with curvature below a preset threshold maintain normal scanning speed and toner delivery.

8. The path planning method according to claim 6, characterized in that, In T4, the specific overlapping rules are as follows: Overlap rate between passes: In the central main bearing area, the overlap rate of adjacent cladding passes is 40%~60%; in the stepped transition area, the overlap rate of adjacent cladding passes is 30%~50%; in the end area, the overlap rate of adjacent cladding passes is 40%~50%; in the round hole avoidance area, the overlap rate of adjacent cladding passes is 20%~40%; in the rounded corner area, the overlap rate gradually changes linearly from the outside to the inside according to the rounded corner arc length. Overlap direction: The central main bearing area and end area adopt unidirectional scanning along the length of the large equipment frame to enable directional grain growth; in the stepped transition area, the scanning direction is reciprocated at a 30° angle to the length of the large equipment frame to form a cross-network structure between adjacent passes; in the circular hole avoidance area, a concentric arc path is adopted around the circular hole, and the scanning direction is consistent with the tangent direction of the hole edge; in the rounded corner area, a radial scanning path is adopted. Interlayer overlap: During multi-layer cladding, the center line of the cladding channel of the next layer is offset by half the width of the first layer channel, so that the upper and lower cladding channels are staggered and the interlayer porosity is eliminated.

9. The path planning method according to claim 5, characterized in that, In T5, the specific steps are as follows: T51. When the maximum travel of the equipment in the length direction of the surface to be processed is less than the total length of the surface to be processed, the surface to be processed is divided into several sub-regions along the length direction, and an overlapping area is set between adjacent sub-regions. T52. Within each sub-region, each functional area adopts a unidirectional scan along the length direction to ensure that the cladding layer grains grow in a directional manner, consistent with the direction of the principal compressive stress during the operation of large equipment. T53. Within the overlapping area, the scanning direction forms an angle of 30° to 45° with the scanning direction inside the sub-region. The scanning speed is reduced by 5% to 15% compared to the sub-region, the laser power is reduced by 5% to 20% compared to the sub-region, and the overlap rate between the cladding channels is 20% to 35%. The overlap width of the overlapping area is selected according to 3 to 5 times the equipment positioning error. T54. Planning the processing sequence between sub-regions: Adopting an alternating sequence strategy, that is, first process the odd-numbered layers of the first sub-region, then process the odd-numbered layers of the second sub-region, and then return to the even-numbered layers of the first sub-region, and so on; the scanning direction of adjacent sub-regions changes alternately between layers, that is, the first sub-region of the first layer is scanned along the length direction, and the second sub-region is scanned along the width direction; the two are interchanged in the next layer, so that the grain direction of the splicing interface is staggered. T55. When the equipment travel is limited and a splicing strategy of partition positioning and reference point reset is required, an additional tempering scan is added to the splicing area. The laser power of the tempering scan is reduced to 50% of the normal value, and the scanning speed is increased to 150% of the normal value.

10. A method for strengthening the surface of a large equipment frame using laser cladding, characterized in that, Includes the following steps: Pre-treatment of the surfaces to be processed on the frame of large equipment; The powder according to any one of claims 1 to 2 is prepared by the preparation method according to any one of claims 3 to 4; A processing path is generated using the path planning method described in any one of claims 5 to 9; The powder is loaded into the powder feeder, and the laser cladding equipment is controlled to perform laser cladding on the surface to be processed on the large equipment frame according to the processing path to form a cladding layer.

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