JPH0427461A - Arc thermal spraying device - Google Patents

Abstract

PURPOSE:To stably show a preferable overall performance under various using conditions by setting the jet-air angle formed by a pair of jet-flow central axes R to be 10-30 degrees. CONSTITUTION:A pair of nozzle openings 27 spouting and supplying plain surface type jet air 26 and a pair of guide members 17 feeding and guiding the material W to be molten to the molten drops generating position Q on the central axis P are disposed in the symmetrical position to the central axis P of melt-spraying in front of a case 1 so as to intersept each other. The spouting central axes R of both jet airs 26 are directed to converge at a convergent part S on the central axis P of meltspraying in front of the molten drops generating position Q. The jet air angle alpha formed by the pair of jet flow central axes R is set to be 10-30 degrees. By this method, the state of arc and the state of film are stably kept in a preferable state even when the quality or the diameter of the material W to be molten is different or the supplying state of jet air is varied, and a preferable overall performance is stably shown.

Description

Detailed Description of the Invention (A) Industrial Application Field This invention forms a wedge-shaped arc chamber with planar shet air jetted from a pair of nozzle ports, and generates droplets within this arc chamber. The present invention relates to an arc thermal spraying apparatus using a so-called cross-shed method.

(b) Prior art The present inventor has developed an arc melting tF of a cross-shet type, which is characterized by the supply form of jet air for atomizing.
He first proposed the J device (patent application No. 63-326730).
No., Patent Application No. 1-91565).

This is because, as shown in FIGS. 1 and 2, it is equipped with a pair of nozzle ports 27 that eject plane jet air 26, and that the ejection center axis R of the jet air 26 ejected from both nozzle holes 27 is , is characterized in that it is oriented so as to converge toward a convergence part S on the thermal spraying center axis P ahead of the droplet generation position Q.

(c) Problems to be Solved by the Invention The above-mentioned cross-jet type arc thermal spraying apparatus has the following features compared to conventional apparatuses.

The ability to miniaturize the arc spraying equipment, the ability to perform stable arc spraying without pinching, the ability to perform low-temperature thermal spraying, and the ability to form sprayed coatings even on combustible materials such as cardboard, and the surface roughness of thermal sprayed coatings. It is possible to obtain a sufficient film thickness with a small amount, and also to obtain good film quality such as high peel strength.Thermal spraying can be performed with a relatively small capacity compressor due to low air consumption during operation.

However, with the above equipment, if the material or diameter of the weld metal differs, or if the jet air supply form changes, the above characteristics may not always be exhibited, and it is difficult to consistently demonstrate the overall performance, so there is room for improvement. There was.

This invention was obtained by developing and improving the previously proposed arc thermal spraying device, and its purpose is to create a cross-jet type arc thermal spraying device that can stably demonstrate comprehensive performance under all usage conditions. It's about getting.

(d) Means for Solving the Problem The inventor listed the elements that are considered to be related to obtaining a good thermal spraying condition, and conducted thermal spraying tests for each of them without changing the usage conditions. , the influence on overall performance was verified. As a result, it was found that the jet air supply conditions, especially the angle between the jet air jet central axes, greatly influenced thermal spraying performance.

Therefore, the arc thermal spraying apparatus of the present invention has a pair of nozzle ports 27 that eject and supply planar jet air 26 at symmetrical positions sandwiching the thermal spraying central axis P in front of the case 1, and a pair of nozzle ports 27 that eject and supply a planar jet air 26, and A pair of guide members 17 that feed and guide the droplets toward the droplet generation position Q are arranged so as to intersect with each other, and the ejection center axis R of both jets 1 and air 26 is forward of the droplet generation position Q. Thermal spraying center axis P
The jet air angle α between the pair of jet central axes R is 1.
The requirement is that the angle be set between 0 and 30 degrees.

(e) If the working jet air angle α is less than 10 degrees, the nozzle opening 2
When the adjacent interval of 7 is constant, the convergence distance becomes long,
Air velocity near convergence part S and jet air 2
6's power (penetration) decreases. Therefore, the droplets cannot be made sufficiently fine, and the particles on the surface of the sprayed film become coarse. The adhesion strength of the scattered particles is also low, and the peel strength of the coating is low.

When the jet air angle α exceeds 30 degrees, the convergence distance becomes shorter, so a part of the jet air 26 collided near the convergence part S returns to the droplet generation position Q side, and the droplets are sucked by the jet air 26. Deteriorate. In other words,
Some of the droplets fall without being atomized, increasing droplet loss. In addition, the arc state becomes unstable due to the return air flow,
Easy to cause pinch phenomenon. If the convergence distance of the jet air 26 is short, are its speed and power sufficient?
I don't like it because it's too strong. Therefore, the suitable droplet generation position Q
However, it is limited to a narrow front and rear range, and the position must be precisely adjusted, resulting in a lack of workability when changing the welding material.

(f) Example (hereinafter referred to as blank space) FIGS. 1 to 5 show an example of an arc thermal spraying apparatus according to the present invention.

In FIGS. 3 and 4, the arc spraying apparatus performs arc spraying using a round wire-shaped welding material W, and the welding material W is passed through a rectangular box-like case 1 in a vertically parallel position. A route is set, a melt material feeding mechanism 2 is provided in the center of the interior of the case 1, and a nozzle 3 for spouting compressed air for atomizing is arranged on the outer surface of the front end of the case 1.

In FIG. 4, a case 1 includes a metal case body 4 with an opening on one side, insulating blocks 5 and 6 fixed to the front and rear ends of the case body 4, and the opening swinging open and closed via a hinge 7. It consists of a lid 8, a bracket 9 for the nozzle 3 that covers the front surface of the front insulating block 5, and the like. The lid 8 is maintained in a closed position by a latch 10, and can be easily opened by pulling the latch 10 against a spring.

Further, the bracket 9 can be removed from the insulating block 5 by loosening the screw 11, which is convenient for replacing the nozzle 3 and the guide member 17.

In order to feed and guide the welding material W, a pair of upper and lower guide tubes 14 are fixed to the insulating block 6 on the rear side, and these guide tubes 14
A direction change guide tube 15 is attached to the front insulating block 5 in accordance with the above. The direction changing kite tube 15 is screwed into a screw hole passing through the power supply terminal 16 in the front and rear directions, so that its mounting position in the front and back direction can be adjusted. The welding material W is supplied with arc current via this guide tube 15.

In order to feed and guide the melt W toward the droplet generation position Q on the central axis P of thermal spraying, a guide member 17 is screwed and fixed to the front side of the upper and lower power supply terminals 16. Both guide members 17 are arranged in an inclined position such that their respective projecting ends approach each other vertically.

The melt material feeding mechanism 2 is disposed between the direction changing guide tube 15 and the guide tube 14, and simultaneously feeds the upper and lower melt materials W toward the front of the case. In FIGS. 3 and 4, the welding material feeding mechanism 2 includes a drive roller 18 made of an insulator that is rotatably supported by the upper and lower walls of the case body 4, and a presser roller that presses the welding material W against the drive roller 18. , drive roller 18
It is composed of a motor 21 and the like that is rotationally driven via a joint 20. The presser roller 19 is rotatably supported by one end of the spring arm 22 and is arranged above and below in correspondence with the drive roller 18. The spring arm 22 is used to press the presser roller 19 and urge the lid 8 to open.

The motor 21 is housed within the grip 23. It can be activated by turning on the switch 24 shown in FIG.

The nozzle 3 is formed in a vertically elongated rectangular shape, and has a groove 25 in its center that avoids the guide member 17, and a pair of nozzle ports 27 that eject jet air 26 are formed along the left and right front edges of the groove 25 through slits. It has a shaped opening. 28 is an air hose, and 29 is a hose joint.

As shown in FIG. 1, the nozzle ports 27 are arranged at symmetrical positions across the thermal spraying central axis P, so that the ejection central axis R of the jet air 26 is aligned with the thermal spraying central axis P ahead of the droplet generation position Q.
It is directed to converge toward the upper convergence section S. Also, the vertical center of the jet air 26 is the thermal spraying center axis P.
The vertical position of the nozzle opening 27 is adjusted so as to coincide with the vertical position of the nozzle opening 27. In the drawing, reference numeral 30 indicates a collective airflow formed in front of the convergence section, and 31 indicates a shield frame that connects the arc light.

The present inventor listed the elements for obtaining a good thermal spraying condition in the above-described arc apparatus, and conducted a thermal spraying test for each item without changing the usage conditions. As shown in FIGS. 1 and 2, the above-mentioned elements include the jet air angle α between the left and right jet air 26, the convergence distance b from the nozzle front end face to the center of the convergence part S, and the nozzle opening 27. slit width C, vertical width d of nozzle opening 27,
The length f of the straight part of the nozzle opening 27 was selected.

By the way, it is said that the hot material protrusion dimension q is desirably as short as possible in order to ensure that the melting materials W come close to each other and stabilize the arc state. On the other hand, in order to prevent clogging of the guide portion 17 due to droplets, it is essential to ensure a certain size or more. Due to these constraints, the warm material protrusion dimension Q is often set within the range of 9 to 131R1n, and can be considered to be approximately constant, so it has been excluded from the above-mentioned elements. Regarding the angle θ sandwiched between the central axes of both guide members 17, if the angle θ exceeds 30 degrees, the feeding resistance of the weld material W increases, and the angle θ becomes 24 degrees.
If the angle is less than 1°, the arc position tends to wander back and forth, and in either case, a stable arc state cannot be obtained and the effective angle range is limited, so this was also excluded from the above elements.

(Test A) Thermal spraying was performed by changing the jet air angle α in the range of 8 to 35 degrees. At this time, a zinc wire with a diameter of 1.1M was used as the welding material W, and an alternating current of 13V was supplied. , the air pressure supplied to the nozzle 3 was 6!j/~.Slit width C
was 1#, the vertical width d of the nozzle opening 27 was 10ay+, the interval e between adjacent nozzle openings 27 was 6NR, and the length f of the straight part of the nozzle opening 27 was 5 m or more.

Jet air angle α (degrees) & 1015253035
Test number 123456 (Test B) The jet air angle α was fixed at 25 degrees, the length of e was changed, the convergence distance was changed to larger or smaller, and the other conditions were the same as those of Test A. The arc state and film state were examined. . In addition, the warm material protrusion dimension q was changed as appropriate within the range of 9 to 13711111.

Convergence distance b (M) 13 15 18 25 30
40 Test number 789101112 (Test C) The slit width C of the nozzle opening 27 is 0.3 to 4 In! ! Haku conducted thermal spraying under the same conditions as Test 1. At this time, the jet air angle α was fixed at 25 degrees.

Slit width Cs O, 30, 61, 2234 Test number 13 14 15 16 17 18 (Test D
) Thermal spraying was performed under the same conditions as Test 3, except that the vertical width d of the nozzle opening 27 was changed in the range of 4 to 20#I.

Vertical width dai 4 6 10 15 20 25 Test number 19 20 21 22 23 24 (Test E
> Thermal spraying was carried out under the same conditions as Test 3, except that the length f of the straight part of the nozzle opening 27 was changed in the range of 3 to 30 m.

(Test results and evaluation) The results obtained from Test A are shown in Table A.

In addition, the codes used in the table below: ○: Good, △: Fair, X
indicates not possible.

(Table A) Test number 1 23456 Seat air angle (α) degree 81015253035 Air velocity
× △ △ ○ ○ ○Power
× △ △ ○ O○ droplet loss △ ○
○ ○ △ × Particle roughness X △ ○ ○
○ △ Peel strength × △ △ ○ ○ ○ Air return ○ ○ ○ △ X-pinch phenomenon
○ ○ ○ ○ △ X As is clear from Table A, when the jet air angle α was less than 10 degrees, the droplets were insufficiently refined, resulting in insufficient particle roughness and peel strength on the film surface. In addition, if the jet air angle α is less than 10 degrees,
Since the convergence distance increases, the hot material protrusion dimension Q must be increased.

When the jet air angle α exceeded 30 degrees, droplet suction was insufficient due to air return and droplet loss increased. Furthermore, a pinch phenomenon was likely to occur, and a stable arc state could not be obtained. Adjustment of the droplet generation position Q was also troublesome. This is due to a slight difference in the front and rear positions of the droplet generation position Q.
This is because the distance between the droplet and the jet air 26 changes greatly, and there is a disadvantage that it requires time and effort to replace the guide member 17 during actual work.

The results obtained in Test B are shown in Table B.

(Table B) Test number 789101112 Convergence distance bsy+ 13 15 18 25 30
40 Arc state × △ ○ ○ ○ ○ Film state △ ○ ○ ○ O△ Air power ○
○ ○ ○ ○ △Pinch phenomenon × △ ○ ○
○ ○In this test group, the convergence distance is 40! It can be said that there is almost no adverse effect on the arc state or film state, except for the drawback that the air power decreases when exceeding Mi. However, the convergence distance for test number 7 was 13 m.
Therefore, it is expected that it will not be possible to cope with the case where it is desired to set the weld metal protrusion dimension Q to be large.

Furthermore, when using the weld metal protrusion dimension q as a reference, the convergence distance should preferably be within the range of 1.5 to 3 times the dimension q, and more preferably should be set to 2 to 2.5 times. .

(mu/+7.@ri The results obtained in Test C are shown in Table C.

(Table C) Test number 13 14 15 16 17 1
8 slit width CM 0.3 0.6 1.2 2 3
4 Air velocity × △ ○ ○ ○ ○ Power of jet air × △ ○ ○ ○ ○III Temperature △ △ ○ ○ ○ ○ Air consumption ○ ○ ○ △ △ XIn this test group, the slit width C is 0.6! If it is smaller than Mi, the air velocity and power of the jet air 26 will be insufficient. Also,
When the length exceeds 3 m, air consumption increases rapidly, and a stable arc condition cannot be maintained unless a large-capacity compressor is used. In other words, as long as the slit width C is not extremely small, it can be said that there is no practical problem in both the arc state and the film state.

The results obtained from the test are shown in the table.

(Table D) Test number 19 20 21 22 23 2
Vertical width of 4 slits dm 4 6 10 15 20 25
Droplet loss △ ○ ○ ○ ○ ○ Air consumption ○ ○ ○ ○ △ × Even if the vertical width d was changed, there was almost no difference in the arc condition and film condition.

When the vertical width d was 4 mm, droplet loss was slightly observed, and it was recognized that there was some concern when using a large diameter wire.Furthermore, when the vertical width was 20 m or more, air consumption increased. An increase was seen.

In addition, as mentioned above, as test E, the straight part length f was 3 m.
, 10#, and 201M 1.30 m, thermal spraying tests were carried out with the jet air 26 injected to 1.30 m, but there was no problem in the linearity of the jet air 26 during jetting, and there was no change in the arc state or film state. Basically, in order to reliably obtain the linearity of the jet air 26, it is more advantageous to have a larger straight portion length f.
Considering that the nozzle 3 becomes larger, it seems that around 20111 m is the maximum limit for a hand-held arc thermal spraying device.

As is clear from the above test results, it was found that the jet air angle α between the pair of jet airs 26 influenced the arc state and the film state. It was also found that the most ideal dimensions and angles of each part are as shown in the table below.

Angle α 5 dimension C dimension d dimension 14~1
8 degrees 25~30# 0.6~1. Os 8-12
Shoe f dimension 9 dimension Angle θ 8~14! Mi9-13m 25-28 degrees (another embodiment) FIGS. 6 and 7 show another embodiment in which the nozzle 3 is changed.

The nozzle 3 shown in FIG. 6 differs from the previous embodiment in that a group of small holes 27a are formed in a vertically linear array, and that the small holes 27a are formed as round holes.

The nozzle 3 shown in FIG. 7 has a nozzle opening 27 formed by a group of small holes 27b vertically arranged in a straight line.
The feature is that 7b is formed by a rectangular hole.

In this way, the nozzle opening 27 can be formed by a group of small holes, and the shape of the small holes can also be changed to any shape.

(Effect of the invention) As explained above, the jet air angle α is 10 to 30
According to the arc thermal spraying apparatus of the present invention specified above, even if the material or diameter of the hot material W changes, or the jet air supply status changes, the arc condition and film condition can be kept stable and in good condition. This allows for stable overall performance while fully demonstrating the characteristics of the cross-jet system. Moreover, when replacing the guide member 17 according to the hot material W to be used, the droplet generation position Q can be easily set, and the work of changing the hot material can be simplified.

[Brief explanation of the drawing]

1 to 5 show an embodiment of the arc spraying apparatus according to the present invention, FIG. 1 is a cross-sectional plan view of the nozzle, FIG. 2 is a longitudinal side view of the nozzle, and FIG. 3 is a longitudinal side view of the arc spraying apparatus. 4 is a cross-sectional plan view of the arc thermal spraying device, and FIG. 5 is a front view of the arc thermal spraying device. 6 and 7 are front views showing other embodiments of the nozzle, respectively. 1・・・・・・・・・Case, 17・・・・・・・・・
Guide member, 26...Jet air,
27...Nozzle opening, P...
・Thermal spraying center axis, Q・・・・・・Droplet generator, R
・・・・・・・・・Ejection center axis, S・・・・・・・・・
Convergence part, W...... Warm material, α...
...Jet air angle, b...Convergence distance, Ω...Protrusion dimension of hot material.

Claims (2)

[Claims] (1) A pair of nozzle ports 27 that eject and supply planar jet air 26 are installed at symmetrical positions across the thermal spraying central axis P in front of the case 1, and a pair of nozzle ports 27 are installed to blow out and supply the jet air 26 to the droplet generating device Q on the thermal spraying central axis P. A pair of guide members 17 for feeding and guiding
are arranged so that they intersect with each other, and the ejection central axes R of both jet airs 26 are oriented so as to converge toward a converging part S on the thermal spraying central axis P ahead of the droplet generation position Q. , the jet air angle α between the pair of jet central axes R is 1
An arc thermal spraying device characterized in that the temperature is set at 0 to 30 degrees. (2) Claim 1 in which the convergence distance b from the nozzle front end surface where the nozzle opening 27 opens to the convergence part S is set to 1.5 to 3 times the weld material protrusion dimension g from the nozzle front end surface to the center of droplet generation. Arc thermal spraying equipment described in .