JP2013049025A - Nozzle for cold spray and cold spray apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the efficiency of the treatment of forming a coating C and the quality of the coating C to a high level.SOLUTION: On the side surface of the box 3 of the apparatus, the first nozzle formation 33 that throttles a flow of a working gas is constituted by a double structure composed of an interior tube 35 and an outer tube 37. The first inner gas passage 39 is formed inside the interior tube 35, and the first annular outer gas passage 41 is formed between the outer peripheral surface of the interior tube 35 and the interior peripheral surface of the outer tube 37. The second nozzle formation 43 expanding a working gas and spraying is disposed concentrically at the tip of the outer tube 37, and the second gas passage 45 is formed inside the second nozzle formation 43. Two or more interior protrusions 47 and two or more outer protrusions 49 are formed at the tip of the interior tube 35 at intervals in the circumferential direction.

Description

  The present invention relates to a cold spray nozzle or the like used in a cold spray apparatus that forms a film by colliding a material powder accompanying a working gas with a surface of an object to be processed in a solid state.

  In recent years, the cold spray technology that forms a film with a dense structure and high adhesion strength by colliding the material powder with the surface of the object to be processed in the solid state has attracted attention. Various developments have been made on spray nozzles. The configuration of a general cold spray nozzle will be described with reference to FIG.

  As shown in FIG. 5A, a general cold spray nozzle 101 includes a first nozzle structure (nozzle restrictor) 103 that restricts the flow of a working gas such as nitrogen, and this first nozzle structure. Inside the body 103, a first gas flow path 105 is formed for circulating the working gas accompanied by the material powder. A second nozzle structure (nozzle expansion portion) 107 that expands and injects the working gas is provided concentrically and integrally at the tip of the first nozzle structure 103, and the second nozzle structure 107. Is formed with a second gas flow path 109 for circulating the working gas, and the second gas flow path 109 communicates with the first gas flow path 105.

  Therefore, when the high-pressure working gas is supplied into the first gas flow path 105 with the high-pressure working gas having a temperature lower than the melting point of the material powder and the working gas is supplied to the first gas flow path 105, the working gas is produced by the first nozzle structure 103. , The working gas is accelerated to supersonic speed and flows from the first gas flow path 105 into the second gas flow path as a supersonic flow. Subsequently, the supersonic flow working gas is expanded by the second nozzle structure 107 and is injected from the second nozzle structure 107 toward the surface of the workpiece W. Thereby, the coating material C can be formed by colliding the material powder accompanying the working gas with the surface of the workpiece W in the solid state.

  In addition, there exist some which are shown to patent document 1-patent document 3 as a prior art relevant to this invention.

JP 2008-80323 A JP 2009-131834 A JP 2008-253889 A

  By the way, during the process of forming the coating C, the material powder tends to adhere to the inner wall surface of the second gas flow path 109, in particular, near the inlet of the inner wall surface of the second gas flow path 109, and the adhesion of the material powder proceeds. As a result, the cold spray nozzle 101 is blocked. In such a case, the process for forming the coating C must be temporarily interrupted and the cold spray nozzle 101 must be replaced, and there is a problem that the process for forming the coating C becomes complicated.

  Further, in the cross section of the second gas flow path 109, the outer peripheral portion expands more rapidly than the center portion, and as shown in FIG. 5B, the outlet side (the cross section on the outlet side) of the second gas flow path 109. ) Tends to have a non-uniform velocity distribution D such that the outer peripheral portion is faster than the central portion. Therefore, when the degree of non-uniformity of the velocity distribution D on the outlet side of the second gas flow path 109 is increased, the film thickness of the coating film C, the adhesion strength of the coating film C, and the like are increased, and the quality of the coating film C is improved. There is a problem that it is difficult to improve the level.

  Therefore, an object of the present invention is to provide a cold spray nozzle or the like having a novel configuration that can solve the above-described problems.

  The first feature of the present invention is that the working gas having a temperature lower than the melting point of the material powder is injected as a supersonic flow toward the surface of the object to be processed, so that the material powder accompanying the working gas is solid-phased. In a cold spray nozzle used in a cold spray device that forms a film by colliding with the surface of the object to be processed in a state, it is constituted by a double structure of an inner tube and an outer tube, A first inner gas flow path for flowing the working gas accompanied by the material powder is formed, and an annular shape for flowing only the working gas between the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube. A first nozzle structure (nozzle restrictor) for constricting the flow of the working gas and a concentrically provided at the tip of the outer tube, and the first inner gas flow inside Road and the first A second gas passage that is communicated with the water gas passage and allows the working gas to flow therethrough, and includes a second nozzle structure (nozzle expansion portion) that inflates and injects the working gas. The gist is that a protrusion is formed at the tip of the tube.

  According to the first feature, the high-pressure working gas is supplied into the first inner gas flow path by causing the material powder to accompany the high-pressure working gas having a temperature lower than the melting point of the material powder. The high-pressure working gas having a temperature lower than the melting point of the material powder is supplied into the first outer gas channel. Then, the flow of the working gas is throttled by the first nozzle structure, and the working gas is accelerated to a supersonic speed. As a supersonic primary flow (primary supersonic flow) from the first inner gas flow path. , And flows into the second gas flow channel from the first outer gas flow channel as an annular supersonic secondary flow (secondary supersonic flow). Subsequently, the supersonic primary flow working gas and the supersonic secondary flow working gas are expanded (expanded / accelerated) by the second nozzle constituent, respectively. Sprayed from the tip toward the surface of the workpiece. Thereby, the said material powder accompanying the said working gas can be made to collide with the surface of the said to-be-processed object in a solid-phase state, and the said film can be formed.

  Here, in the second gas flow path, the supersonic secondary flow surrounds the supersonic primary flow, and a boundary between the supersonic primary flow and the supersonic secondary flow. Aerodynamically capable of ejecting the working gas as a primary flow of the supersonic wave, having a parallel portion parallel to the axis of the second nozzle structure (the axis of the cold spray nozzle) in the vicinity of the outlet. Nozzles can be defined. In addition, by forming the protrusion at the tip of the inner tube, a vertical vortex as a three-dimensional turbulence is generated in a shear layer between the primary flow of the supersonic and the secondary flow of the supersonic. Since the growth of the two-dimensional vortex (two-dimensional large-scale vortex) generated in the shear layer can be suppressed (suppressed), the supersonic primary flow and the supersonic secondary flow can be mixed. Sufficiently suppressed, the shape of the aerodynamic nozzle can be stably maintained. This makes it difficult for the material powder to adhere to the inner wall surface of the second gas flow path, so that the cold spray nozzle can be prevented from being blocked, and the outlet side (outlet side) of the second gas flow path can be avoided. Of the primary flow of the supersonic velocity in the horizontal cross section of FIG.

  In particular, by setting the temperature of the working gas supplied into the first outer gas channel sufficiently lower than the temperature of the working gas supplied into the first inner gas channel. The entire inner wall surface of the second gas flow path can be cooled (film cooling) by the working gas of the supersonic secondary flow. This makes it difficult for the material powder to adhere to the inner wall surface of the second gas flow path, so that the cold spray nozzle can be sufficiently and reliably prevented from being blocked during the coating forming process.

  Furthermore, the supersonic primary flow and the supersonic secondary flow are adjusted by adjusting the ratio of the supply flow rate of the working gas supplied into the first inner gas passage and the first outer gas passage, respectively. The position of the boundary portion of the flow can be moved closer to and away from the axis of the second nozzle structure. Thereby, the expansion ratio of the supersonic primary flow can be set to an expansion ratio corresponding to the pressure of the working gas.

  The second feature of the present invention is that the working gas having a temperature lower than the melting point of the material powder is jetted toward the surface of the object to be processed as a supersonic flow so that the material powder accompanying the working gas is solid-phased. A gist of the present invention is that a cold spray nozzle having the first feature is used in a cold spray apparatus that forms a film by colliding with the surface of the object to be processed in the state.

  According to the 2nd characteristic, there exists an effect | action similar to the effect | action by a 1st characteristic.

  According to the present invention, the material powder is less likely to adhere to the inner wall surface of the second gas flow path, and the clogging of the cold spray nozzle can be avoided sufficiently and reliably. The efficiency of the coating film forming process can be improved by minimizing the replacement of the cold spray nozzle.

  In addition, since the velocity distribution of the supersonic primary flow at the outlet side of the second gas flow path can be made close to a uniform velocity distribution, variations in the film thickness of the coating, variations in the adhesion strength of the coating, etc. Without it, the quality of the coating can be improved with a high bell.

  Furthermore, since the expansion ratio of the supersonic primary flow can be set to an expansion ratio according to the pressure of the working gas, even when the pressure of the working gas is changed, the supersonic primary flow in the second gas flow path. The quality of the coating can be maintained by properly expanding the flow of working gas.

FIG. 1 is a cross-sectional view of a cold spray nozzle according to an embodiment of the present invention. FIG. 2 is a schematic diagram of a cold spray apparatus according to an embodiment of the present invention. FIG. 3A is an enlarged cross-sectional view of the distal end side of the inner tube in the cold spray nozzle according to the embodiment of the present invention, and FIG. 3B is an enlarged view of an arrow B in FIG. is there. 4 (a), 4 (b), and 4 (c) are enlarged cross-sectional views of the distal end side of the inner tube of another aspect in the cold spray nozzle according to the embodiment of the present invention. FIG. 5A is a cross-sectional view of a general cold spray nozzle, and FIG. 5B is a diagram showing a velocity distribution on the outlet side of the second flow path.

  An embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 2, the cold spray apparatus 1 according to the embodiment of the present invention injects a working gas having a temperature lower than the melting point of the material powder toward the surface of the workpiece W as supersonic flows F1 and F2. By this, it is an apparatus which forms the film C by making the material powder accompanying the working gas collide with the surface of the workpiece W in the solid state. Here, in the embodiment of the present invention, the material powder is a powder of a metal such as copper aluminum, titanium, silver, nickel, zinc, tin, molybdenum, iron, tartan, niobium, silicon, chromium, or titanium alloy. Nickel-chromium alloy, stainless steel, aluminum alloy, copper alloy and other alloy powders, alumina and other ceramic powders are used, and the working gas is an inert gas such as nitrogen, helium, or argon.

  The cold spray device 1 is operated by a device casing 3, a cold spray nozzle 5 detachably provided on a side surface of the device casing 3, and a cold spray nozzle 5 provided inside the device casing 3. And a gas supply unit 7 for supplying gas. The specific configuration of the gas supply unit 7 is as follows.

  In the apparatus housing 3, a gas cylinder 9 is provided as a gas supply source for storing a working gas such as high-pressure nitrogen having a pressure of 40 atmospheres or more. Further, one end of a main pipe 11 for circulating a high-pressure working gas is connected to the gas cylinder 9, and one end of a branch pipe 13 for circulating a high-pressure working gas is provided in the middle of the main pipe 11. Is branched. Further, the gas cylinder 9 is connected to one end of a sub pipe 15 for circulating a high-pressure working gas accompanied by the material powder. A powder supply source for supplying the material powder is provided in the middle of the sub pipe 15. A powder feeder 17 is provided.

  A valve 19 capable of adjusting the opening degree (opening area) of the main pipe 11 is disposed at one end side (upstream in the supply direction) of the main pipe 11 with respect to the branch part (branch part to the branch pipe 13). . Further, a valve 21 capable of adjusting the opening degree of the main pipe 11 is disposed at the other end side (downstream in the supply direction) of the branch portion in the main pipe 11. Further, a valve 23 for adjusting the opening degree of the branch pipe 13 is arranged in the middle of the branch pipe 13, and a valve 25 for adjusting the opening degree of the sub pipe 15 is arranged in the middle of the sub pipe 15. Has been.

  Between the branch portion in the main pipe 11 and the valve 19, a resistance heating heater 27 that heats the working gas to a predetermined low temperature (for example, 400 degrees) lower than the melting point of the material powder is disposed. Between the branch portion in the main pipe 11 and the valve 21, a resistance heating type heater 29 that heats the working gas to a predetermined high temperature (for example, 800 degrees) lower than the melting point of the material powder is disposed. Further, a resistance heating type heater 31 for heating the working gas to a predetermined high temperature is disposed in the middle of the sub-pipe 15.

  Then, the specific structure of the nozzle 5 for cold spray which is the principal part of embodiment of this invention is demonstrated.

  As shown in FIGS. 1 and 2, a first nozzle structure (nozzle restricting portion) 33 for restricting the flow of the working gas is detachably provided on the side surface of the apparatus housing 3. This first nozzle structure The body 33 is constituted by a double structure of an inner tube 35 and an outer tube 37. In addition, a first inner gas flow path 39 for circulating the working gas accompanied by the material powder is formed inside the inner pipe 35, and the distal end side of the first inner gas flow path 39 is in the distal direction. The diameter is reduced toward. Further, the first inner gas flow path 39 is connected to the other end of the main pipe 11 and the other end of the sub pipe 15, and the first inner gas flow path 39 is heated to a predetermined high temperature and is made of a material. A working gas accompanied by powder is supplied.

  Between the outer peripheral surface of the inner tube 35 and the inner peripheral surface of the outer tube 37, an annular first outer gas channel 41 for allowing only working gas to flow is formed. The distal end side is reduced in diameter toward the distal end direction. The first outer gas channel 41 is connected to the other end of the branch pipe 13 so that the working gas heated to a predetermined low temperature is supplied into the first outer gas channel 41. It has become.

  A second nozzle configuration body (nozzle expansion portion) 43 that inflates and injects the working gas is integrally provided at the tip of the outer tube 37, and inside the second nozzle configuration body 43, A second gas flow path 45 for flowing the working gas is formed. The second gas flow path 45 communicates with the first inner gas flow path 39 and the first outer gas flow path 41, and the second gas flow path 45 is formed from within the first inner gas flow path 39. As the supersonic primary flow (primary supersonic flow) F1, the working gas flows in from the first outer gas passage 41 as an annular supersonic secondary flow (secondary supersonic flow) F2. Yes.

  As shown in FIGS. 3A and 3B, a plurality of inner protrusions 47 protruding radially inward are formed at the distal end of the inner tube 35 at intervals in the circumferential direction. The height is set smaller than the thickness of the boundary layer F1a of the supersonic primary flow F1. A plurality of outer projections 49 projecting radially outward are formed at the distal end of the inner tube 35 at intervals in the circumferential direction, and the height of each inner projection 47 is a supersonic secondary flow F2. Is set smaller than the thickness of the boundary layer F2a. Instead of forming a plurality of inner projections 47 and a plurality of outer projections 49 at the tip of the inner tube 35, only the plurality of inner projections 47 or a plurality of outer projections as shown in FIGS. Only 49 may be formed, or a plurality of axial protrusions 51 protruding in the axial direction of the inner tube 35 may be formed at the tip of the inner tube 35 as shown in FIG. .

  Then, the effect | action and effect of embodiment of this invention are demonstrated.

  The opening degree of the main pipe 11 is adjusted by the valves 19 and 21, and high-pressure working gas is passed (circulated) from the gas cylinder 9 through the valve 19, the heater 27, the valve 21, and the heater 29, and the sub pipe 15 The high pressure working gas heated to a predetermined high temperature is entrained by passing the high pressure working gas from the gas cylinder 9 through the valve 25, the heater 31, and the powder supplier 17 by adjusting the opening degree of the gas. Thus, a high-pressure working gas is supplied into the first inner gas passage 39. In addition to adjusting the opening degree of the main pipe 11 with the valve 19, the opening degree of the branch pipe 13 is adjusted with the valve 23, and high-pressure working gas is passed from the gas cylinder 9 through the valve 19, the heater 27, and the valve 23. By doing so, a high-pressure working gas heated to a predetermined low temperature is supplied into the first outer gas channel 41. Then, the flow of the working gas is throttled by the first nozzle structure 33, the working gas is accelerated to supersonic speed, and the first outer gas flow path 41 is formed as the supersonic primary flow F1 from the first inner gas flow path 39. It flows into the second gas flow path 45 from the inside as an annular supersonic secondary flow F2. Subsequently, the working gas of the supersonic primary flow F1 and the working gas of the supersonic secondary flow F2 are expanded (expanded / accelerated) by the second nozzle structure 43, respectively, from the tip of the second nozzle structure 43. Sprayed toward the surface of the workpiece W. Thereby, the coating material C can be formed by colliding the material powder accompanying the working gas with the surface of the workpiece W in the solid state.

  Here, in the second gas flow path 45, the supersonic secondary flow F2 surrounds the supersonic primary flow F1, and the boundary between the supersonic primary flow F1 and the supersonic secondary flow F2. Has a parallel portion 53p parallel to the axis of the second nozzle structure 43 (the axis of the cold spray nozzle 5) in the vicinity of the outlet, and has a shape approximating the outer shape of the rocket nozzle and the working gas. The aerodynamic nozzle 53 that can be ejected as the supersonic primary flow F1 can be partitioned (formed). Further, by forming a plurality of inner protrusions 47 and a plurality of outer protrusions 49 at the tip of the inner tube 35, as shown in FIG. 3B, a supersonic primary flow F1 and a supersonic secondary flow F2 are obtained. A vertical vortex 55 as a three-dimensional turbulence is generated in the shear layer S between the two and the two-dimensional vortex (two-dimensional large-scale vortex) 57 generated in the shear layer S is suppressed ( (Refer to Japanese Patent No. 4211298), the mixing of the supersonic primary flow F1 and the supersonic secondary flow F2 can be sufficiently suppressed to stably maintain the shape of the aerodynamic nozzle 53. it can. This makes it difficult for the material powder to adhere to the inner wall surface of the second gas flow path 45, thereby preventing the cold spray nozzle 5 from being blocked. As shown in FIG. 1, as shown in FIG. The velocity distribution D of the supersonic primary flow F1 on the outlet side (cross section on the outlet side) can be made closer to a uniform velocity distribution.

  In particular, since the temperature of the working gas supplied into the first outer gas passage 41 is set sufficiently lower than the temperature of the working gas supplied into the first inner gas passage 39, the supersonic speed is increased. The entire inner wall surface of the second gas flow path 45 can be cooled (film cooling) by the working gas of the secondary flow F2. Thereby, it becomes difficult for material powder to adhere to the inner wall surface of the 2nd gas flow path 45, and obstruction | occlusion of the nozzle 5 for cold spray can be avoided sufficiently and reliably.

  Furthermore, the supersonic primary flow F1 and the supersonic secondary flow are adjusted by adjusting the ratio of the supply flow rate of the working gas supplied into the first inner gas passage 39 and the first outer gas passage 41, respectively. The position of the boundary portion of F2 can be moved closer to and away from the axis of the second nozzle structure 43. Thereby, the expansion ratio of the supersonic primary flow F1 can be set to the expansion ratio according to the pressure of the working gas. Note that the expansion ratio of the supersonic primary flow F1 refers to the crossing of the tip (throat portion) of the first inner gas flow path 39 with respect to the cross sectional area Ao of the supersonic primary flow F1 on the outlet side of the second gas flow path 45. It is the ratio of area Ai (Ao / Ai).

  Therefore, according to the embodiment of the present invention, the material powder is less likely to adhere to the inner wall surface of the second gas flow path 45 and the clogging of the cold spray nozzle 5 can be avoided sufficiently and reliably. During the forming process, it is possible to improve the efficiency of the forming process of the coating C by minimizing the replacement of the cold spray nozzle 5.

  In addition, since the velocity distribution D of the supersonic primary flow F1 on the outlet side of the second gas flow channel 45 can be made to be close to a uniform velocity distribution, variations in the film thickness of the coating C, variations in the adhesion strength of the coating C, and the like. The quality of the film C can be improved with a high bell.

  Furthermore, since the expansion ratio of the supersonic primary flow F1 can be set to an expansion ratio according to the pressure of the working gas, the supersonic primary flow F1 in the second gas flow path 45 even when the pressure of the working gas is changed. The quality of the coating C can be maintained by appropriately expanding the working gas.

  In addition, this invention is not restricted to description of the above-mentioned embodiment, It can implement in a various aspect by making an appropriate change. Further, the scope of rights encompassed by the present invention is not limited to these embodiments.

W Workpiece C Coating F1 Supersonic primary flow F1a Supersonic primary flow boundary layer F2 Supersonic secondary flow F2a Supersonic secondary flow boundary layer S Shear layer 1 Cold spray device 3 Device casing 5 Nozzle for cold spray 7 Gas supply unit 9 Gas cylinder 11 Main pipe 13 Branch pipe 15 Sub pipe 17 Powder feeder 19 Valve 21 Valve 23 Valve 25 Valve 27 Heater 29 Heater 31 Heater 33 First nozzle structure 35 Inner pipe 37 Outer pipe 39 First inner gas channel 41 First outer gas channel 43 Second nozzle structure 45 Second gas channel 47 Inner projection 49 Outer projection 51 Axial projection 53 Aerodynamic nozzle 53p Parallel portion 55 Vertical vortex 57 Two-dimensional vortex (Two-dimensional large-scale vortex)

Claims (6)

By injecting the working gas having a temperature lower than the melting point of the material powder toward the surface of the object to be processed as a supersonic flow, the material powder accompanying the working gas remains in a solid state and remains in the solid state. In a cold spray nozzle used in a cold spray device that forms a film by colliding with the surface,
A first inner gas flow path configured to circulate the working gas accompanied by the material powder is formed inside the inner pipe, the inner pipe and the outer pipe having a double structure; An annular first outer gas passage for allowing only the working gas to flow between the inner peripheral surfaces of the outer pipe, and a first nozzle structure for restricting the flow of the working gas;
A second gas flow path is formed concentrically at the distal end of the outer pipe, and communicates with the first inner gas flow path and the first outer gas flow path and circulates the working gas inside; A second nozzle structure for inflating and injecting the working gas,
A nozzle for cold spraying, wherein a projection is formed at the tip of the inner tube.   At least the front end side of the first inner gas flow path is reduced in diameter toward the front end direction, and at least the front end side of the first outer gas flow path is reduced in diameter toward the front end direction. The nozzle for cold spray according to claim 1.   The nozzle for cold spray according to claim 1 or 2, wherein the protrusion protrudes radially inward of the inner pipe.   The cold spray nozzle according to claim 1, wherein the protrusion protrudes radially outward of the inner tube.   The nozzle for cold spray according to claim 1 or 2, wherein the protrusion protrudes in an axial direction of the inner tube. By injecting the working gas having a temperature lower than the melting point of the material powder toward the surface of the object to be processed as a supersonic flow, the material powder accompanying the working gas remains in a solid state and remains in the solid state. In a cold spray device that forms a film by colliding with the surface,
A cold spray device using the cold spray nozzle according to any one of claims 1 to 5.

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