Annular laser cladding nozzle

Abstract

The invention discloses an annular laser cladding nozzle which comprises a nozzle body, a laser channel is formed in the center of the nozzle body, the nozzle body is provided with a plurality of gas-powder mixing cavities, an annular powder channel, a cooling channel and an annular gas storage bin, and the gas-powder mixing cavities are annularly formed in the periphery of the laser channel at intervals; each gas-powder mixing cavity is communicated with a powder feeding channel for inputting metal powder, a lower outlet of each gas-powder mixing cavity is communicated with an annular powder channel, and the annular powder channel is provided with a plurality of flow guide baffles. Powder enters the gas-powder mixing cavity and flows into the annular powder channel by means of gravity and air pressure. A flow guide baffle arranged in the annular powder channel effectively guides powder to flow, concentrated accumulation is prevented, and uniform distribution is guaranteed. The cooling efficiency of the nozzle is improved through the design of the cooling channel, cooling liquid circulates along an S-shaped loop, and it is ensured that the nozzle stably works under the high-temperature condition. In addition, the annular gas storage bin is further arranged, local excessive concentration of shielding gas is avoided, and therefore the stability of the cladding process is improved.

Description

Technical Field

[0001] The invention relates to the technical field of laser cladding, and in particular to an annular laser cladding nozzle. Background Art

[0002] Laser cladding is a very promising remanufacturing technology that can rebuild the geometric features of parts and restore their original mechanical properties by cladding layer by layer. The cladding layer material and part of the substrate are melted together and cooled rapidly, so that a high-quality coating with good metallurgical bonding ability is obtained on the surface of the substrate. Laser cladding technology has the advantages of high processing efficiency, low coating dilution rate and high bonding strength with the substrate, high degree of automation, environmental friendliness, and diversified cladding powder alloys.

[0003] At present, the powder feeding methods of laser cladding nozzles mainly include coaxial powder feeding and off-axis powder feeding, among which coaxial powder feeding can be divided into multi-beam coaxial powder feeding, annular coaxial powder feeding, etc. The choice of powder feeding method has a crucial impact on the cladding quality. The advantage of the annular coaxial powder feeding nozzle is that it can avoid the blockage of traditional nozzles caused by powder aggregation, and to a certain extent alleviate the powder concentration problem caused by single-point powder feeding nozzles. However, in practical applications, the annular coaxial powder feeding nozzle still faces some problems: 1. During the powder feeding process of the annular nozzle, the powder will still be unevenly distributed when it falls. The powder is more concentrated in some areas, forming an accumulation, while other areas are sparse and insufficiently covered. Therefore, during the cladding process, excessive metallurgical bonding may occur in some areas, while insufficient metallurgical bonding in other areas may affect the overall quality of the cladding layer. 2. The high temperature generated by the laser beam after reflection on the substrate surface will damage the nozzle. 3. Most of the existing water cooling channels are straight-through water channels with limited cooling effect. The coolant absorbs heat during the cooling process, resulting in poor subsequent cooling effect and failure to completely cool the lower end of the nozzle. Therefore, even with a water cooling system, the nozzle will still be damaged by the reflected high temperature. Summary of the invention

[0004] The purpose of the present invention is to provide an annular laser cladding nozzle to solve one or more technical problems existing in the prior art and at least provide a beneficial choice or create conditions.

[0005] The technical solutions adopted to solve the above technical problems are: The present invention provides an annular laser cladding nozzle, comprising a nozzle body, a laser channel is provided at the center of the nozzle body, a plurality of gas-powder mixing chambers and an annular powder channel are provided on the nozzle body, the plurality of gas-powder mixing chambers are arranged around the laser channel in an annular manner, the annular powder channel is arranged on the lower side of the gas-powder mixing chamber, each of the gas-powder mixing chambers is connected to a powder feeding channel for inputting metal powder, a lower outlet of the gas-powder mixing chamber is connected to the annular powder channel, the annular powder channel is provided with a plurality of guide baffles, at least two guide baffles are arranged at the lower end of the outlet of the gas-powder mixing chamber, and the upper end of the guide baffle corresponds to the lower end of the outlet of the gas-powder mixing chamber.

[0006] The beneficial effects of the present invention are: During the laser cladding process, the required powder and conveying gas enter the gas-powder mixing chamber through the powder delivery channel. The gas-powder mixing chamber serves as a temporary storage space, and under the combined action of gravity and air pressure, the powder falls and flows into the annular powder channel. The annular powder channel is the core structure of the present invention for achieving uniform powder feeding. Two or more guide baffles are provided in the annular powder channel to reasonably guide the flow path of the powder and avoid the powder from being concentrated and accumulated directly below the gas-powder mixing chamber. The guide baffle can effectively divert the powder to the sparse area to avoid the powder from being retained or accumulated at the baffle. At the same time, the width of the guide baffle gradually increases from top to bottom, so that the powder is more evenly distributed during the falling process, thereby avoiding the problem of local cladding quality degradation caused by powder accumulation.

[0007] As a further improvement of the above technical solution, the guide baffle is upwardly arc-shaped and protrudes, and the width of the guide baffle gradually increases from top to bottom.

[0008] As a further improvement of the above technical solution, the nozzle body is further provided with a cooling channel, and the cooling channel includes an S-shaped loop covering the outer peripheral wall of the plurality of nozzle bodies.

[0009] As a further improvement of the above technical solution, there are two cooling channels, and the cooling channel includes an S-shaped loop section and a straight flow section, wherein the S-shaped loop section is respectively connected to the outlet and the straight flow section of the cooling channel, and the straight flow section is connected to the inlet of the cooling channel, and the outlet and inlet of the cooling channel are both arranged on the upper side of the nozzle body.

[0010] As a further improvement of the above technical solution, the nozzle body is provided with an outer shell, the outer side wall of the nozzle body is provided with a cooling channel, and the outer shell is sleeved on the outer side of the nozzle body to form a cooling channel.

[0011] As a further improvement of the above technical solution, the nozzle body is also provided with an annular air storage bin and an annular protective air channel. The annular protective air channel is arranged below the annular air storage bin, the annular protective air channel is connected to the annular air storage bin, and the outlet of the annular protective air channel is arranged parallel to the laser channel.

[0012] As a further improvement of the above technical solution, the annular gas storage bin is arranged on the outer periphery of the multiple gas-powder mixing chambers.

[0013] As a further improvement of the above technical solution, the nozzle body includes an inner core and an outer sleeve on the outside of the inner core, the laser channel is arranged at the center of the inner core, and the plurality of gas-powder mixing chambers and annular powder channels are arranged between the inner core and the outer sleeve.

[0014] As a further improvement of the above technical solution, the inner core is provided with an annular boss, and the top of the outer sleeve is arranged below the annular boss.

[0015] As a further improvement of the above technical solution, a first annular step is provided on the lower side of the annular boss, and a second annular step matching the annular step is provided on the top of the outer sleeve. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present invention will be further described below in conjunction with the accompanying drawings and embodiments; Figure 1 This is a schematic structural diagram of an embodiment of an annular laser cladding nozzle provided by the present invention, wherein two arrows represent upward and downward directions respectively; Figure 2 This is a cross-sectional view of an embodiment of an annular laser cladding nozzle provided by the present invention, wherein two arrows indicate upward and downward directions respectively; Figure 3 1 is a schematic structural diagram of an inner core of an embodiment of an annular laser cladding nozzle provided by the present invention, wherein two arrows represent upward and downward directions respectively; Figure 4 This is a front view of an inner core of an embodiment of a ring-shaped laser cladding nozzle provided by the present invention, wherein two arrows indicate upward and downward directions respectively; Figure 5 This is a schematic diagram of powder flow of an annular laser cladding nozzle provided by the present invention, in which two arrows represent upward and downward directions respectively; Figure 6 The present invention provides an annular laser cladding nozzle, and a schematic diagram of the outer sleeve structure of one embodiment thereof, wherein two arrows represent upward and downward directions respectively.

[0017] Reference numerals: Powder inlet pipe 100, nozzle body 200, gas-powder mixing chamber 201, annular powder channel 202, cooling channel 203, laser channel 204, powder delivery channel 205, annular gas storage bin 206, annular protective gas channel 207, inner core 210, annular boss 211, first annular step 212, outer sleeve 220, guide baffle 230, outer shell 240, air inlet pipe 300, cooling water inlet pipe 400, cooling water outlet pipe 500. DETAILED DESCRIPTION

[0018] This section will describe in detail the specific embodiments of the present invention. The preferred embodiments of the present invention are shown in the accompanying drawings. The purpose of the accompanying drawings is to supplement the description of the text part of the specification with graphics, so that people can intuitively and vividly understand each technical feature and the overall technical solution of the present invention, but it cannot be understood as a limitation on the scope of protection of the present invention.

[0019] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., and orientations or positional relationships indicated are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0020] In the description of the present invention, if there are words such as "several", it means one or more, "more" means more than two, greater than, less than, exceed, etc. are understood as not including the number, and above, below, within, etc. are understood as including the number.

[0021] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0022] Reference Figures 1 to 6 , a ring-shaped laser cladding nozzle of the present invention is made into the following embodiments: The annular laser cladding nozzle includes a powder inlet pipe 100 and a nozzle body 200. The nozzle body 200 is provided with a gas-powder mixing chamber 201, an annular powder channel 202, a cooling channel 203 and a laser channel 204. The laser channel 204 is used to guide the irradiation of the laser beam, the gas-powder mixing chamber 201 is used to mix and transport metal powder, and the cooling channel 203 ensures the heat dissipation performance of the nozzle and prolongs the service life. The laser beam passes through the laser channel 204, and the metal powder is input into the gas-powder mixing chamber 201. In the gas-powder mixing chamber 201, the powder and the gas are mixed evenly. Subsequently, the mixture is ejected through the nozzle and irradiated by the laser beam outside the nozzle, thereby being heated and melted. The melted mixture is ejected from the opening of the nozzle, directly irradiated and attached to the surface of the workpiece. The various components cooperate with each other to achieve stable and efficient powder transmission and uniform distribution, as well as efficient cooling of the nozzle.

[0023] Specifically, the nozzle body 200 includes an inner core 210 and an outer shell 220, wherein the outer shell 220 is sleeved on the outer surface of the inner core 210 to facilitate the production and setting of the internal channel structure. In some other embodiments, the nozzle body 200 can be provided in one piece.

[0024] The laser channel 204 is arranged at the center of the inner core 210. The cross section of the laser channel 204 gradually decreases from top to bottom to guide the irradiation of the laser beam. Four gas-powder mixing chambers 201 and an annular powder channel 202 are arranged between the inner core 210 and the outer sleeve 220. The annular powder channel 202 is arranged at the lower side of the four gas-powder mixing chambers 201. The lower outlets of the four gas-powder mixing chambers 201 are all connected to the annular powder channel 202. Each gas-powder mixing chamber 201 is connected to a powder delivery channel 205 for inputting metal powder. The powder delivery channel 205 is connected to a powder feeding pipe 100. There are four powder feeding pipes 100 in total, which are distributed above the four gas-powder mixing chambers 201. The powder feeding pipe 100 is connected to an external powder feeding system. During the laser cladding process, the required powder and conveying gas enter the powder delivery channel 205 through the powder feeding pipe 100 and then enter the gas-powder mixing chamber 201. The gas-powder mixing chamber 201 serves as a temporary storage space, and under the combined effect of gravity and air pressure, the powder falls and flows into the annular powder channel 202 .

[0025] In order to achieve uniform powder feeding, the annular powder channel 202 is provided with a plurality of guide baffles 230, two of which are provided at the lower end of the outlet of the gas-powder mixing chamber 201, and the upper end of the guide baffle 230 corresponds to the lower end of the outlet of the gas-powder mixing chamber 201. Figure 4Two guide baffles 230 are provided at the lower end of the outlet of the gas-powder mixing chamber 201 to reasonably guide the flow path of the powder and prevent the powder from accumulating directly below the gas-powder mixing chamber 201. The guide baffle 230 is designed to be slightly convex upward, which can effectively divert the powder to the sparse area and prevent the powder from being retained or accumulated at the baffle. At the same time, the width of the baffle gradually increases from top to bottom, so that the powder is distributed more evenly during the falling process, thereby avoiding the problem of local cladding quality reduction caused by powder accumulation. Powder flow diagram Figure 5 .

[0026] In some other implementations, a plurality of guide baffles 230 may be provided and evenly distributed at the lower end of the outlet of the gas-powder mixing chamber 201 .

[0027] To further improve the working stability of the nozzle, refer to Figure 6 The nozzle body 200 is also provided with a cooling channel 203. The present invention adopts a dual cooling channel 203 design to construct an efficient cooling system. The two cooling channels 203 cover both sides of the nozzle periphery respectively, cool equal areas, and further improve the cooling effect.

[0028] The cooling channel 203 includes an S-shaped loop section and a straight inlet section, wherein the S-shaped loop section is respectively connected to the outlet of the cooling channel 203 and the straight inlet section, the straight inlet section is respectively connected to the lower end inlet of the S-shaped loop section and the inlet of the cooling channel 203, the inlet of the cooling channel 203 is connected to the cooling water inlet pipe 400, the outlet of the cooling channel 203 is connected to the cooling water outlet pipe 500, and the outlet and inlet of the cooling channel 203 are both arranged on the upper side of the nozzle body 200. The S-shaped loop section enables the coolant to be more evenly distributed on the outer side wall of the nozzle body 200, thereby improving the cooling efficiency. This design is conducive to the effective heat dissipation of the nozzle body 200 during operation, and prevents performance degradation or damage caused by excessive temperature.

[0029] The coolant enters the bottom of the nozzle through the straight inlet section, then flows upward along the S-shaped loop section for cooling, and finally is discharged from the upper outlet of the S-shaped loop section. Since the temperature at the lower end of the nozzle is higher, the initial temperature of the coolant is lower. By cooling from the higher temperature, the temperature of the entire nozzle body 200 can be evenly cooled. At the same time, another coolant enters from the straight inlet section and flows from top to bottom to the lower end of the S-shaped loop section, and is discharged from the upper outlet of the S-shaped loop section after passing through the lower cooling channel 203. Such a cooling layout ensures that both sides of the nozzle are effectively cooled simultaneously, overcoming the defect of insufficient cooling of the lower part of the nozzle in the traditional single-channel cooling system. All cooling water inlet pipes 400 and cooling water outlet pipes 500 are designed above the nozzle, which effectively avoids the problem of pipe damage due to high temperature. The double cooling design makes the nozzle temperature distribution more uniform, significantly improves the service life and working stability of the nozzle, and is particularly suitable for long-term high-temperature working environments.

[0030] In some other embodiments, the coolant channel is only provided with an S-shaped loop section, and the coolant channel enters from the lower end of the nozzle body 200 and then flows out from the upper end.

[0031] The nozzle body 200 is provided with an outer shell 240 , and an outer wall of the nozzle body 200 is provided with a cooling channel. The outer shell 240 is sleeved on the outer side of the nozzle body 200 to form a cooling channel 203 .

[0032] In some other embodiments, an S-shaped bent water pipe is provided on the nozzle body 200 for cooling.

[0033] Compared with directly setting a water pipe on the nozzle body 200 for cooling, the nozzle body 200 is provided with an outer shell 240, and the outer wall of the nozzle body 200 is provided with a cooling groove. The outer shell 240 is sleeved on the outside of the nozzle body 200 to form a cooling channel 203. The design has the following advantages: the design of the cooling groove enables the coolant to be more evenly distributed on the outer wall of the nozzle body 200, thereby avoiding the problem of uneven local cooling caused by the fixed position of the water pipe; it helps to reduce the temperature difference between different parts of the nozzle body 200, ensuring the stability and consistency of the overall temperature of the nozzle body 200; and improving the overall structural strength of the nozzle body 200.

[0034] In addition, the nozzle body 200 is also provided with an annular gas storage bin 206 and an annular shielding gas channel 207. The annular shielding gas channel 207 is provided below the annular gas storage bin 206, and the annular shielding gas channel 207 is communicated with the annular gas storage bin 206. The outlet of the annular shielding gas channel 207 is arranged in parallel with the laser channel 204. The cross section of the annular gas storage bin 206 is roughly circular. The shielding gas system is provided with two shielding gas inlets, which are distributed on the side of the nozzle together with the cooling channel 203. The shielding gas inlet is connected to the air inlet pipe 300. The shielding gas enters through the shielding gas inlet and is evenly distributed to the annular gas storage bin 206, and then discharged through the annular shielding gas channel 207, thereby avoiding the problem of excessive concentration of shielding gas in a local area and ensuring the stability of the cladding process. The outlet of the annular shielding gas channel 207 is designed to be parallel to the laser to minimize the disturbance to the molten pool.

[0035] In order to facilitate production, the inner core 210 is provided with an annular boss 211, and the top of the outer sleeve 220 is arranged below the annular boss 211, and the annular boss 211 and the top of the outer sleeve 220 are fixedly connected by screws. The lower side of the annular boss 211 is provided with a first annular step 212, and the top of the outer sleeve 220 is provided with a second annular step adapted to the annular step, which can be correspondingly snapped during installation.

[0036] During the laser cladding process, the laser is emitted from the laser channel 204, and the required powder and conveying gas enter the powder delivery channel 205 through the powder delivery pipe, and then enter the gas-powder mixing chamber 201. The gas-powder mixing chamber 201 serves as a temporary storage space, and under the combined action of gravity and air pressure, the powder falls and flows into the annular powder channel 202. The annular powder channel 202 is the core structure of the present invention for achieving uniform powder feeding. Two guide baffles 230 are provided in the annular powder channel 202 to reasonably guide the flow path of the powder and avoid the powder from being concentrated and accumulated directly below the gas-powder mixing chamber 201; at the same time, the protective gas enters the annular gas storage bin 206 through the air inlet pipe 300, and flows out from the annular protective gas channel 207 after being evenly mixed in the annular gas storage bin 206, and its gas outlet direction is parallel to the laser jetting direction; at the same time, the coolant enters the bottom of the nozzle through the straight inlet section, and then flows upward along the S-shaped loop section for cooling, and finally is discharged from the upper end outlet of the S-shaped loop section, and the entire nozzle is evenly cooled.

[0037] The present invention overcomes the problems of concentrated powder accumulation and uneven cooling in the prior art through optimized structural design, improves the uniformity of powder distribution and the temperature control stability of the nozzle during laser cladding, and has high application value and practicality.

[0038] The preferred embodiments of the present invention are specifically described above, but the invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the invention. These equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A ring-shaped laser cladding nozzle, characterized in that: The invention comprises a nozzle body (200), wherein a laser channel (204) is provided at the center of the nozzle body (200), and the nozzle body (200) is provided with a plurality of gas-powder mixing chambers (201) and an annular powder channel (202). The plurality of gas-powder mixing chambers (201) are arranged around the laser channel (204) in an annular manner at intervals, and the annular powder channel (202) is arranged at the lower side of the gas-powder mixing chamber (201). Each gas-powder mixing chamber (201) is connected to a powder feeding channel (205) for inputting metal powder, and the lower outlet of the gas-powder mixing chamber (201) is connected to the annular powder channel (202). The annular powder channel (202) is provided with a plurality of guide baffles (230), and at least two guide baffles (230) are arranged at the lower end of the outlet of the gas-powder mixing chamber (201), and the upper end of the guide baffle (230) corresponds to the lower end of the outlet of the gas-powder mixing chamber (201).

2. The annular laser cladding nozzle according to claim 1, characterized in that: The guide baffle (230) is convex in an upward arc shape, and the width of the guide baffle (230) gradually increases from top to bottom.

3. The annular laser cladding nozzle according to claim 1, characterized in that: The nozzle body (200) is further provided with a cooling channel (203), wherein the cooling channel (203) comprises an outer peripheral wall of the plurality of nozzle bodies (200) in an S-shaped loop.

4. The annular laser cladding nozzle according to claim 3, characterized in that: There are two cooling channels (203), and the cooling channel (203) comprises an S-shaped loop section and a straight flow section, wherein the S-shaped loop section is respectively connected to the outlet and the straight flow section of the cooling channel (203), and the straight flow section is connected to the inlet of the cooling channel (203), and the outlet and the inlet of the cooling channel (203) are both arranged on the upper side of the nozzle body (200).

5. The annular laser cladding nozzle according to claim 4, characterized in that: The nozzle body (200) is provided with an outer shell (240), an outer side wall of the nozzle body (200) is provided with a cooling channel, and the outer shell (240) is sleeved on the outer side of the nozzle body (200) to form a cooling channel (203).

6. The annular laser cladding nozzle according to claim 1, characterized in that: The nozzle body (200) is further provided with an annular gas storage bin (206) and an annular protective gas channel (207); the annular protective gas channel (207) is provided below the annular gas storage bin (206); the annular protective gas channel (207) is communicated with the annular gas storage bin (206); and the outlet of the annular protective gas channel (207) is arranged parallel to the laser channel (204).

7. The annular laser cladding nozzle according to claim 6, characterized in that: The annular gas storage bin (206) is arranged on the outer periphery of the plurality of gas-powder mixing chambers (201).

8. The annular laser cladding nozzle according to claim 1, characterized in that: The nozzle body (200) comprises an inner core (210) and an outer sleeve (220) sleeved on the outer core (210); the laser channel (204) is arranged at the center of the inner core (210); and the plurality of gas-powder mixing chambers (201) and the annular powder channel (202) are arranged between the inner core (210) and the outer sleeve (220).

9. The annular laser cladding nozzle according to claim 8, characterized in that: The inner core (210) is provided with an annular boss (211), and the top of the outer sleeve (220) is arranged below the annular boss (211).

10. The annular laser cladding nozzle according to claim 9, characterized in that: A first annular step (212) is provided on the lower side of the annular boss (211), and a second annular step matching the annular step is provided on the top of the outer sleeve (220).

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