TWI543821B - Plasma spraying device - Google Patents

Description

Plasma spraying device

The present invention relates to a plasma spraying apparatus which sprays a plasma arc to an electrically conductive wire to generate a plasma flame while ejecting the wire as a droplet.

Figure 6 is a conceptual cross-sectional view of a conventional plasma spraying apparatus. As shown in Fig. 6, the conventional plasma spraying device 90 includes a primary gas nozzle 91 that forms a primary gas passage 91a, and a secondary gas nozzle 92 that is disposed outside the primary gas nozzle 91 to form a secondary gas passage 92a. a cathode 93 on a substantially central axis of the nozzle opening 91b of the primary gas nozzle 91 and the nozzle opening 92a of the secondary gas nozzle 92; a power supply device 94; and an electric conduction for spraying the vicinity of the nozzle opening 92a of the secondary gas nozzle 92 The wire guide hole 95 of the wire W.

The wire W is supplied obliquely from the wire guiding hole 95 toward the center axis of the nozzle opening 92a. Further, the primary gas ejected from the primary gas passage 91a is generated between the wire W that is indirectly connected to the anode side of the power supply device 94 via the secondary gas nozzle 92, and the cathode 93 that is connected to the cathode side of the power supply device 94. The arc generated occurs to become a plasma flame F, and the wire W is sprayed by the droplet D. The droplet D is further refined by the secondary gas injected from the secondary gas passage 92a toward the front of the secondary gas nozzle 92, and is acceleratedly sprayed onto the workpiece T to form the spray coating S.

Therefore, when the plasma spraying device of the wire W is sprayed by the droplets by using the plasma flame F and the secondary gas flow, in order to stably generate the plasma flame F, a droplet D is sprayed, and the wire W is wound. The front end must remain in place inside the plasma flame F at all times.

However, in the conventional plasma spraying device, the wire guiding hole 95 for supplying the wire W is formed into a circular cross-sectional shape, and is larger than the metal in order to avoid jamming or blocking due to the original deformation state of the wire W. The diameter of the outer diameter of the wire W. Therefore, it is very difficult to feed while correcting the twist of the wire W, and the wire W is repeatedly guided away from the center of the plasma flame F due to the curling habit, and the problem of the wire being supplied to the center of the plasma flame F cannot be stably settled.

Therefore, for example, the improvement described in Patent Document 1 is to provide a correction guide member that clamps a wire member to a support plate integrated with a plasma arc torch, and corrects the primary bending; The correcting guiding member guides the wire to a secondary bending guiding member that performs a secondary bending of the wire beyond its elastic limit; and the supply of the wire is performed by removing the original deformation normal state of the wire. The front end of the wire is kept at the center of the plasma gas flow at all times, and a plasma flame occurs in a stable manner.

[Patent Document 1] Japanese Patent Laid-Open Publication No. Hei 9-308970

However, as disclosed in Patent Document 1, when the secondary bending guide member that performs the secondary bending of the wire beyond the elastic limit is integrated with the plasma arc torch, the force of the wire feeding is due to the secondary bending guiding member. The wire is subjected to a secondary bending exceeding the elastic limit and is excessively large. Therefore, the wire supply mechanism is enlarged, and the entire fire moment tends to be large.

Therefore, the object of the present invention is to provide a small-sized plasma spraying device, which is independent of the original deformation state of the wire when the wire is supplied near the nozzle opening of the secondary gas nozzle, and does not need to be provided with the wire exceeding the elastic limit. The secondary curved secondary curved guiding member can stably feed the wire.

A plasma spraying apparatus according to the present invention includes: a cathode; a primary gas nozzle that forms a primary gas passage on the outer circumference of the cathode and covers an end portion of the cathode: is disposed on the outer side of the primary gas nozzle and forms a secondary gas passage twice a gas nozzle; and a wire passage for supplying a coating wire to the vicinity of the nozzle opening of the secondary gas nozzle; and using an arc generated between a tip end of the wire supplied from the wire passage and the cathode The primary gas injected by the gas nozzle is plasma-formed to form a plasma flame sprayed by the primary gas nozzle so that the front end of the wire becomes a droplet, and the secondary gas injected by the plasma flame and the secondary gas nozzle is used to treat the object to be treated. A plasma spraying device for spraying the droplets, the wire passage having a slightly rectangular cross-sectional shape elongated in a direction in which the plasma flame extends, imparting a bending to the wire not exceeding a range of elastic limits.

According to the plasma spraying device of the present invention, the wire is given a bending not exceeding the elastic limit range, so that the curling habit of the wire is relaxed toward the stretching direction of the plasma flame, preventing the position in the direction perpendicular to the direction in which the plasma flame extends. Offset. Moreover, the front end portion of the wire is displaced even if it is displaced relative to the direction in which the plasma flame extends, because the plasma flame is not unstable because it is located on the axis of the plasma flame. Therefore, according to the plasma spraying apparatus of the present invention, the wire can be stably supplied to the center portion of the plasma flame.

Here, the cross-sectional shape of the wire passage having a substantially rectangular shape is preferably such that the width in the short-side direction is larger than the diameter of the wire by 3% or more and 10% or less. Thereby, the curling habit of the wire can be substantially relieved only in the direction in which the plasma flame extends, while preventing the positional deviation in the direction perpendicular to the direction in which the plasma flame extends. Further, when the width in the short-side direction is only 3% or more larger than the diameter of the wire, the gap between the curling habit of the wire and the direction in which the plasma flame is stretched may be insufficient to catch or block. On the other hand, when the width in the short side direction is larger than the diameter of the wire by 10% or more, if the gap is too large, the curling habit of the wire may not only be soothed toward the stretching direction of the plasma flame, but also relieved in the direction of the right angle.

The wire passage has a primary wire passage having a wire outlet formed near a nozzle opening of the secondary gas nozzle; and a secondary wire passage for supplying the wire at a specific inclination angle with respect to the primary wire passage. Thereby, when the wire is fed from the secondary wire passage to the primary wire passage, the wire is given a bending angle not exceeding the elastic limit range of the wire at a specific inclination angle, so that the curling habit of the wire is toward the plasma flame. The direction of extension is soothing, and the positional deviation in the direction perpendicular to the direction in which the plasma flame extends is prevented.

At this time, the specific inclination angle is preferably 1 to 5°. Thereby, the wire can be imparted with a bending which does not exceed the elastic limit range of the wire, and the wire can be stably supplied to the center portion of the plasma flame. Further, when the specific inclination angle is 1 or less, the wire cannot be specifically bent, and the wire feeding may not be performed stably. On the other hand, when the specific inclination angle exceeds 5°, it is possible to impart a bending exceeding the elastic limit range of the wire.

Further, it is preferable that the primary wire passage and the secondary wire passage are disposed with a gap of 3 to 10 mm. Thereby, a wire passage which is shaped like a large curve is formed by the gap between the primary wire passage and the secondary wire passage, and the wire can be given a bending not exceeding the range of the elastic range. Further, when the gap is 3 mm or less, it is substantially the same as that formed by using one primary wire passage. On the other hand, when the gap exceeds 10 mm, the effect of bending the wire by the secondary wire passage is small, and in this case, it is substantially the same as that formed by using one primary wire passage.

(1) The wire passage has a slightly rectangular cross-sectional shape elongated in the direction in which the plasma flame extends, imparting a bending to the wire not exceeding the range of its elastic limit, and does not need to be disposed to exceed the elastic limit of the wire. The secondary bending secondary bending guiding member can make the original deformation normal state of the wire soothe in the direction of stretching of the plasma flame, and can prevent the positional deviation in the direction perpendicular to the direction in which the plasma flame extends, and can be used for plasma The center of the flame is supplied with a stable supply of wire.

(2) The slightly rectangular cross-sectional shape of the wire passage, the width in the short-side direction is larger than the diameter of the wire by more than 3% and less than 10%, and the curling habit of the wire is substantially only toward the plasma flame. The direction of extension is soothing, and the positional deviation in the direction perpendicular to the direction in which the plasma flame extends is prevented, so that the wire can be stably supplied to the center portion of the plasma flame.

(3) a wire passage having: a primary wire passage having a wire outlet formed near a nozzle opening of the secondary gas nozzle; and a supply of the wire at an inclination angle of 1 to 5° with respect to the primary wire passage The secondary wire passage can impart a bend to the wire that does not exceed the elastic limit of the wire, and the wire can be stably supplied to the center of the plasma flame.

(4) The primary wire passage and the secondary wire passage are arranged with a gap of 3 to 10 mm, and the primary wire passage and the secondary wire passage form a wire passage which is intended to have a large curve shape, and the wire can be given no Bending beyond the range of the elastic range.

Fig. 1 is a schematic configuration view of a plasma spraying apparatus according to an embodiment of the present invention, and Fig. 2 is a detailed longitudinal sectional view of a main part of a plasma flame moment of Fig. 1, and Fig. 3 is a second drawing. The arrow direction diagram of Fig. 4, Fig. 4 is the operation diagram of the plasma flame moment of Fig. 1.

In the first embodiment, a plasma spraying apparatus 1 according to an embodiment of the present invention has a plasma spraying flame 2 for spraying a wire W which becomes a droplet due to a plasma flame toward a workpiece; a plasma spraying torch 2 supplies a gas supply source 3 for primary gas and secondary gas; a power source 4 for supplying operating power to the plasma spraying torch 2; a wire spool 5 for winding back the wire W; The wire straightening machine 6 of the crimping haw of the wire W which is pulled out of the wire reel 5; and the wire supplying mechanism 7 which supplies the wire W to the plasma spraying torch 2 by the wire feeding tube 8.

As shown in Fig. 2, the plasma spraying torch 2 includes a primary gas nozzle 10 that forms a primary gas passage 11, and a secondary gas nozzle 20 that is disposed outside the primary gas nozzle 10 to form a secondary gas passage 21; The tertiary gas nozzle 30 of the tertiary gas passage 31 is formed between the primary gas nozzle 10 and the secondary gas nozzle 20; and is disposed on the substantially central axis of the nozzle opening 12 of the primary gas nozzle 10 and the nozzle opening 22 of the secondary gas nozzle 20. The cathode 40; and a wire passage 50 for supplying the coating wire W to the vicinity of the nozzle opening 22 of the secondary gas nozzle 20.

The primary gas nozzle 10 is formed to cover the front end portion of the cathode 40, and a primary gas passage 11 is formed on the outer periphery of the cathode 40. The primary gas supplied to the primary gas passage 11 is an inert gas such as a nitrogen gas or an argon gas. Alternatively, compressed air may be used for the primary gas. The primary gas supplied from the primary gas passage 11 is injected from the nozzle opening 12 of the primary gas nozzle 10 toward the front of the secondary gas nozzle 20.

The tertiary gas nozzle 30 is formed to surround the outside of the primary gas nozzle 10, and a tertiary gas passage 31 is formed on the outer periphery of the primary gas nozzle 10. The three gases are compressed air and carbon dioxide gas. The secondary gas nozzle 20 is formed to surround the outside of the tertiary gas nozzle 30, and a secondary gas flow path 21 is formed on the outer periphery of the tertiary gas nozzle 30. The secondary gas is a gas such as compressed air or carbonic acid gas.

The wire passage 50 is composed of a primary wire passage 51a having a wire outlet 51b formed near the nozzle opening 22 of the secondary gas nozzle 20; and a supply wire at a specific inclination angle θ with respect to the primary wire passage 51a W secondary wire passage 52a; In the wire passage 50, the wire W is given a bending which does not exceed the elastic limit range by the primary wire passage 51a and the secondary wire passage 52a.

As shown in Fig. 3, the primary wire passage 51a has a substantially rectangular cross-sectional shape in which the plasma flame extends in a long direction, and a primary wire guiding member that is disposed in a straight line outside the secondary gas nozzle 20 The way of 51 is formed. Similarly, the secondary wire passage 52a has a substantially rectangular cross-sectional shape in which the plasma flame extends in a long direction, and is disposed in a straight line so as to be disposed in a position perpendicular to the primary wire passage 51a. The lead member 52 is formed in a manner.

The width a of the primary wire passage 51a in the longitudinal direction is set to be larger than the diameter d of the wire W by 10% or more and 95% or less. Further, the width b of the primary wire passage 51a in the short-side direction is set to be larger than the diameter d of the wire W by 3% or more and 10% or less. Further, the diameter d of the wire W of the present embodiment is 1.6 mm, the width a in the longitudinal direction is set to be larger than the diameter d of the wire W by about 0.2 to 1.5 mm, and the width b in the short-side direction is set to be larger than the wire W. The diameter d is as large as 0.05 to 0.15 mm. The secondary wire passage 52a is also the same.

Further, the one-time wire passage 51a and the secondary wire passage 52a have a substantially rectangular cross-sectional shape, and the rectangular cross-sectional shape is included in a range in which the corner portion of the rectangular cross-sectional shape does not contact the outer surface of the wire W. The shape of the surface chamfering or R-face chamfering. Therefore, in the primary wire passage 51a and the secondary wire passage 52a, the wire W of the present embodiment receives the force in the vertical direction only with respect to the plane of the plane in the longitudinal direction or the plane of the short side direction.

Further, the inclination angle θ of the primary wire passage 51a with respect to the secondary wire passage 52a is an angle formed by the center line of the primary wire passage 51a and the center line of the secondary wire passage 52a. In the present embodiment, the inclination angle θ is set to about 1 to 5 degrees. Further, the secondary wire guiding member 52 is disposed at a position separated from the primary wire passage 51a and the secondary wire passage 52a by a gap c. In the present embodiment, the gap c is set to about 3 to 10 mm.

In the case where the plasma spraying torch 2 of the present embodiment is disposed with the primary wire passage 51a and the secondary wire passage 52a via the gap c, the primary wire passages 51a and the secondary wires are linear. The wire passage 52a forms a wire passage 50 which is intended to have a large curved shape, and imparts a bending to the wire W not exceeding the range of the elastic range. Further, each of the primary wire passage 51a and the secondary wire passage 52a can be curved.

The anode side of the power source 4 is coupled to the primary wire guiding member 51 and indirectly coupled to the wire W passing through the primary wire passage 51a of the primary wire guiding member 51. On the other hand, the cathode side of the power source 4 is connected to the cathode 40. Further, the anode side of the power source 4 is directly connected to the wire W.

In the above-described plasma spraying apparatus 1, when the wire W wound from the wire reel 5 is fed to the plasma spraying torch 2 by the wire supplying mechanism 7, the strong curling habit of the wire W is the wire straightening machine 6 Corrected, and stretched into a gentle curve. And, the wire W is supplied to the wire passage 50 via the wire feed pipe 8. In the wire passage 50, the wire W in the primary wire passage 51a and the secondary wire passage 52a receives only a force perpendicular to the plane of the plane in the longitudinal direction or the plane in the short side direction, and As shown in Fig. 4, the bending of the plasma flame F is not exceeded in the elastic limit range.

Here, the primary wire passage 51a and the secondary wire passage 52a have a substantially rectangular cross-sectional shape in which the plasma flame F extends in a long direction, and the curling habit is soothed toward the extending direction of the plasma flame F. In particular, in the present embodiment, the width b in the short-side direction is set to be larger than the diameter d of the wire W by 3% or more and 10% or less, and is not soaked in a direction perpendicular to the direction in which the plasma flame F extends. . Therefore, even if the front end portion of the wire W is displaced relative to the direction in which the plasma flame F is extended, the positional deviation in the direction perpendicular to the direction in which the plasma flame F is elongated can be prevented, and the axis of the plasma flame F is located. on-line.

Figure 5 is the cross-sectional shape of the wire passage and the direction of the force to which the wire is subjected. In Fig. 5, a slightly rectangular cross section A is a rectangular cross-sectional shape, and a substantially rectangular cross-section B is a shape in which a corner of a rectangular cross-sectional shape is in contact with the outer surface of the wire W by a C-face chamfering process, and a slightly rectangular section C is used. The shape in which the corner portion of the rectangular cross-sectional shape contacts the outer surface of the wire W is subjected to the R-face chamfering process. In the case of the substantially rectangular cross-sectional shape, even if the wire W contacts the plane in the longitudinal direction or the plane in the short-side direction, it only receives the force in the vertical direction with respect to each plane.

The wire W cannot be completely corrected to a straight line by the wire correcting mechanism 7, and has a curling habit. Further, the wire feeding tube 8 is retracted from the plasma spray flame 2 during the operation, and the curved shape has various states of change and cannot maintain a constant shape. Therefore, the wire W having the curling habit is fed in the wire feeding tube 8 having the shape as shown above, and the bending and twisting force of the shape of the wire feeding tube 8 acts on the wire W. Because of the bending and twisting force, the wire W is freely bent in the same manner as the spring within the elastic limit, and is fed in the wire feeding tube 8 while being placed in a direction in which the force is stabilized.

At this time, in the above-described slightly rectangular cross-sectional shape, when the wire W contacts the plane in the short-side direction, it receives the force in the vertical direction with respect to the plane of the short-side direction, that is, the direction in which the plasma flame F is extended. (hereinafter, also referred to as "X direction"), the curling habit is soothing toward the direction of the plasma flame F. Further, when only the plane in the short-side direction is received and the direction perpendicular to the direction in which the plasma flame F is extended (hereinafter, also referred to as "Y-direction") force is applied, the gap width W of the wire W in the short-side direction is satisfied. When moving freely and contacting the plane in the longitudinal direction, at this time, the position of the wire W is stabilized by the action of the force in the vertical direction (Y direction) with respect to the plane of the longitudinal direction. In particular, when the torsional force is applied, the forces in the short-side direction and the long-side direction of the force dispersed in the X direction and the Y direction are applied to the respective faces in the vertical direction, because the metal wire W is suppressed from twisting, and the metal is acted upon. The position of the wire W is stable.

On the other hand, in the case of a circular cross section or an elliptical cross section, when the wire W contacts the curved surface of the circular cross section or the elliptical cross section, only a vertical force acts on the curved surface, and the wire W can move freely along the curved surface. In particular, when the torsional force is received, the wire W is free to rotate along the curved surface without suppressing the twist of the wire W. Therefore, the direction of the force that the wire W is subjected to is indeterminate, and the position of the wire W is unstable.

Therefore, in the plasma spraying apparatus 1 of the present embodiment, the wire W can be stably supplied to the center portion of the plasma flame F at the front end portion of the wire W. Further, the primary gas discharged from the primary gas passage 11 is caused to be indirectly connected between the wire W on the anode side of the power source 4 and the cathode 40 connected to the cathode side of the power source 4 via the primary wire guiding member 51. The arc is plasmated to become a plasma flame F, and the wire W is sprayed by the droplet D. The droplet D is further refined by the secondary gas injected from the secondary gas passage 21 toward the front side of the secondary gas nozzle 20, and is acceleratedly sprayed onto the workpiece T to form a spray coating S.

At this time, in the plasma spraying apparatus 1 of the present embodiment, the inside of the three gas flows which are disposed in the tertiary gas passage 31 between the primary gas passage 11 and the secondary gas passage 21, the heat of the plasma flame F is formed. It becomes a high-temperature gas injection G. The high-temperature gas injection G suppresses the disturbance generated in the outer peripheral portion of the plasma flame F by rapidly injecting the secondary gas injected on the outer side thereof, prevents the gas diffusion of the plasma flame F, and reduces the surface oxidation of the particles which become the droplet D. . Thereby, the spray coating S having less oxidation can be formed on the workpiece T.

Further, when the tertiary gas is a nitrogen gas or an argon gas of an inert gas, it not only prevents the secondary gas which is rapidly mixed as described above but also causes disturbance in the outer peripheral portion of the plasma flame F, and is formed in the outer peripheral portion of the plasma flame F. The inert gas is injected at a high temperature by the heat of the plasma flame F. Thereby, the particles of the droplet D are made fine by the high-temperature inert gas jet in a state in which the composition of the particles is prevented from being changed, and are accelerated to prevent oxidation by the secondary gas. Thereby, it is possible to form the spray coating S which is less oxidized.

Further, in the present embodiment, both the primary wire passage 51a and the secondary wire passage 52a have a substantially rectangular cross-sectional shape in which the plasma flame extends in a long direction. However, only one of them may have a plasma flame extension. A slightly rectangular cross-sectional shape with a long direction. At this time, the primary wire passage or the secondary wire passage having a slightly rectangular cross-sectional shape in which the plasma flame extends in a long direction can make the curling habit of the wire W soothe in the direction in which the plasma flame F is stretched, and is electrically The center portion of the slurry flame F supplies the front end portion of the wire W.

The plasma spraying apparatus of the present invention is very useful for a device for forming a coating film for preventing smashing on the surface of a steel structure.

1. . . Plasma spraying device

2. . . Plasma spray flame

3. . . Gas supply

4. . . power supply

5. . . Wire reel

6. . . Wire straightening machine

7. . . Wire supply mechanism

10. . . Primary gas nozzle

11. . . Primary gas passage

12. . . Nozzle mouth

20. . . Secondary gas nozzle

twenty one. . . Secondary gas path

twenty two. . . Nozzle mouth

30. . . Three gas nozzle

31. . . Triple gas path

40. . . cathode

50. . . Wire passage

51. . . Primary wire guiding member

51a. . . Primary wire passage

52. . . Secondary wire guiding member

52a. . . Secondary wire passage

Fig. 1 is a schematic configuration diagram of a plasma spraying apparatus according to an embodiment of the present invention.

Fig. 2 is a detailed longitudinal sectional view showing the main part of the plasma spray flame of Fig. 1.

Fig. 3 is a view of the arrow A of Fig. 2;

Fig. 4 is an explanatory view of the operation of the plasma spray flame of Fig. 1.

Fig. 5 is a cross-sectional view of the cross-sectional shape of the wire passage and the direction of the force to which the wire is taken.

Figure 6 is a conceptual cross-sectional view of a conventional plasma spraying apparatus.

4. . . power supply

10. . . Primary gas nozzle

11. . . Primary gas passage

12. . . Nozzle mouth

20. . . Secondary gas nozzle

twenty one. . . Secondary gas path

twenty two. . . Nozzle mouth

30. . . Three gas nozzle

31. . . Triple gas path

40. . . cathode

50. . . Wire passage

51. . . Primary wire guiding member

51a. . . Primary wire passage

51b. . . Wire outlet

52. . . Secondary wire guiding member

52a. . . Secondary wire passage

D. . . Droplet

F. . . Plasma flame

G. . . Gas injection

S. . . Spray coating

T. . . Treated object

W. . . metallic line

Claims (7)

A plasma spraying device comprising: a cathode; a primary gas nozzle that forms a gas passage at a periphery of the cathode and covers an end portion of the cathode; and a secondary gas nozzle disposed on an outer side of the primary gas nozzle to form a secondary gas passage And a wire passage for supplying a coating wire to the vicinity of the nozzle opening of the secondary gas nozzle; and an arc generated between the tip end of the wire supplied from the wire passage and the cathode The primary gas injected by the primary gas nozzle is plasma-formed to form a plasma flame sprayed by the primary gas nozzle, so that the front end of the wire becomes a droplet, and the plasma flame and the secondary gas nozzle are a plasma spraying device for spraying the droplets onto the object to be treated, wherein the wire passage has a slightly rectangular cross-sectional shape that is longer in a direction in which the plasma flame extends. To impart a bend to the aforementioned wire that does not exceed the range of the elastic limit. The plasma spraying apparatus according to claim 1, wherein the wire passage has a substantially rectangular cross-sectional shape, and a width in a short side direction is larger than a diameter of the wire by 3% or more and less than 10% or less. . The plasma spraying device according to claim 1, wherein the wire passage has a primary wire passage having a wire outlet formed near a nozzle opening of the secondary gas nozzle; and a primary metal The wire passage supplies the secondary wire passage of the aforementioned wire at a specific inclination angle. The plasma spraying apparatus according to claim 2, wherein the wire passage has a primary wire passage having a wire outlet formed near a nozzle opening of the secondary gas nozzle; and a primary metal The wire passage supplies the secondary wire passage of the aforementioned wire at a specific inclination angle. The plasma spraying apparatus according to claim 3, wherein the specific inclination angle is 1 to 5°. The plasma spraying apparatus according to claim 4, wherein the specific inclination angle is 1 to 5°. The plasma spraying apparatus according to any one of claims 3 to 6, wherein the primary wire passage and the secondary wire passage are disposed with a gap of 3 to 10 mm therebetween.