JPS6360828B2 - - Google Patents

Description

[Detailed Description of the Invention] The conventional thermal spraying method uses a hand-cut thermal spraying machine that conforms to the apparent geocentric definition of ``a method of spraying molten or semi-molten metal.'' Immediately after the metal particles adhere to the object, they cool and simultaneously shrink. The cumulative effect of this shrinkage is so large that it has been difficult to obtain a flat film with a thickness of only 0.1 m/m without distortion for more than 70 years since its creation. There are restrictions.

Apart from the above-mentioned apparent theory, he invented a method of spraying solid metal particles to obtain various metal moldings with excellent quality and no distortion, and is planning to put it into practical use. Patent No. 673182 and Patent No. 1068648 as well as patent application No. 181936 and Patent No. 181936.
- No. 174889, is an invention of a method to further improve the performance of this new thermal spraying machine.

In other words, in the case of high-melting point metals such as nickel, it is difficult to cool the sprayed particles to about atmospheric temperature with a limited amount of air, as with zinc and brass, so it is difficult to cool the sprayed particles to about atmospheric temperature with a limited amount of air. There was a constraint that I had to use lines. After examining the cooling method, it was discovered that unexpected phenomena overlapped, and countermeasures were also taken.

When a zinc wire is used in various metal spraying machines and each machine performs concentrated spraying on one point on a rigid metal surface, a thick sprayed coating (molded product) in the shape of Mt. Fuji is unexpectedly obtained. This thermal spray material is by no means rare, but it exhibits various phenomena. FIG. 1 illustrates two types of quarter cross sections of these molded products. A in the figure shows a spraying machine using the patented thermal spraying machine, which is adhered to the target object 54 without distortion. B represents a state in which various types of conventional thermal spraying machines were used, and the shape was distorted due to severe strain and the material was naturally peeled off from the object being irradiated.

The blowing gas (air) that utilizes the expansion power of gas is explosive and extremely high velocity when ejected.
Expansive properties are always at work, one of which is the spreading phenomenon. There is a sudden decrease in speed and density (atmospheric pressure) proportional to the divergence angle, resulting in a state close to a vacuum where various capacities are zero.

Compared to this gas, metal particles have a huge mass and have a strong tendency to fly at high speed in a bullet-like direction in a given direction at the time of initial velocity.The appearance of this is the shape of Mt. Fuji, which is similar to the accumulation of falling sand in an hourglass. Judging from the fact that the bonding state of the particles to the inclined surface is unusually poor and brittle, the particle distribution density at the center of the airflow axis is approximately the same as that of an hourglass, and no influence of the airflow is seen after the initial velocity.

While the airflow speed decreases rapidly, the speed of the particles is high and they pass through the axial center of the airflow in a group, and are heated by the residual heat of the particles, whereas the temperature of the outer circumference is low. In terms of quantity, it is 6 to 7 times larger than the axis. Therefore, the effect of controlling the divergence phenomenon alone should add considerably to the cooling effect. This heat distribution state is represented by the shading in Figure 2, and this shading also corresponds to the degree of distribution of particles, since it corresponds to the Mt. Fuji formation in Figure 1. .

The outline of the method for improving the above-mentioned undesirable cooling effect is shown in Figure 3.The necessity of providing a control pipe on the outer periphery of the jet air flow to suppress the divergence is as described above, and this control pipe is used as described above. With multiple uses other than this, as a dual ejector device, a comprehensive cooling effect can be obtained by utilizing a large amount of air, stirring, and increasing the density of airflow, resulting in the highest thermal spraying machine ever in terms of spray amount and quality. Now I can get it.

The process of achieving this result is detailed below. In consideration of the molded products A and B in FIG. 1 and the heat distribution in FIG. 2, an example will be described in which a control tube with a wide end and a low internal resistance is used on a trial basis in the third diagram.

One end of this control pipe 50 is connected in a diagrammatic manner to the thermal spray tube 1, which is composed of an annular injection port 18 of a unique type with extensive experience. The compressed air sent from the compressed air supply pipe 4 in the figure is ejected from the annular injection port 18 after passing through the directly connected high-pressure atmosphere 31, forming a conical body 60 whose apex is the confluence point 20 of the injection airflow, and whose base is It is open and the arrow 6 passes through the center of the spray tube 1.
A large amount of air is inhaled from section 6 by the ejector action, and this air is absorbed by the jet airflow from the confluence point 20 and becomes an increased airflow, forming a high-pressure, high-velocity, narrow-angle airflow, and then passing through the control pipe. From the axis of 50, it radiates out of the tube in front. When the airflow at the most intense gathering part 20 of the jet airflow tries to penetrate the inside of the pipe in a straight line, the airflow shows a phenomenon of spreading out from the outer periphery and behaves as if it has countless protrusions, and the airflow itself The characteristics peculiar to gases, such as induction, mixing, disturbance, and heat exchange of the gases in contact with the gases, create a field of second ejector action, and create a large-capacity vacuum zone between the control tube 50 and the inner wall of the control tube 50. , the air is drawn into the wave form from the numerous vents 51, and the air and the jet air flow become turbulent, sometimes producing a "resonant sound", and the strong advancing inertia of the axial air flow and the large amount of air push against each other inside the pipe. The air flows in a flexible manner, and the annular heat distribution 53 collapses, forming a relatively high-density, low-temperature (close to atmospheric temperature) airflow that penetrates the inside of the pipe. Note that if the tip of the control tube 50 is made longer than the figure, the gas density within the tube can be improved to a certain extent and the gas temperature can be lowered.

When the injection port 18 is activated, the conical body 6
When the inflow of the atmosphere is blocked to the inside of 0 (low pressure atmosphere) 19, this area forms a high vacuum sphere. In addition, when sand is supplied to the area together with the atmosphere, the sand scatters forward at high speed, exerting the effect of a so-called sandblasting device, causing scratches on steel and glass surfaces in the form of a pear-like surface. Demonstrates the power to penetrate. When steel grit is used instead of sand, the scratches are deeper than those created by sand, but never form a film. However, when a metal solution is supplied in the same manner as described above, a metal film is formed on most finely rough solid surfaces including paper.

This phenomenon seems difficult to understand immediately.

Am I not explaining my theory enough? Was it because of the period when contrasting old theories were being rekindled? No one thought of this as an empty theory, but the experimental thermal spraying machine of the patent mentioned above has become popular among leading companies, and they have proven this phenomenon as a fait accompli with their products and are developing advanced products. Nickel and high-nickel high melting point metals and alloys are becoming more sophisticated and are experiencing inconvenience due to insufficient cooling. This invention was created to solve the problem of using high-grade practical materials such as chrome steel, and in order to understand this phenomenon, which may be difficult to believe on paper alone, it is necessary to keep the following conditions in mind.

There is no corresponding item in the "Illustrated Illustration of Powder Properties" which collects many powders, and unlike general powders that are crushed by contact with hard objects, high-temperature molten metals are immersed in turbulent high-pressure gas. When crushed, it becomes a large dendritic powder with a large volumetric surface area, which instantly causes cooling and solidification. In particular, high-pressure gas has a high density and a cooling power close to that of a liquid, and turbulent conditions enhance this ability. The shape of this powder corresponds to that captured by a high-speed camera at the moment of a flying volcanic bomb or a powerful wave, but due to the structure and behavior of the powder, it resembles a snow fragment. The explanation is the easiest to understand. That is, they have in common the ability to be sprayed individually, their strong intertwining properties, and the ability to solidify or become rigid in response to pressure applied to the group.

Powder with such properties is injected like a bullet from 20 parts at the apex of the conical jet gas, and the air flow in the front part is thermally diluted into the atmosphere and has a cross-sectional area of about 3 minutes. When the mixed airflow, which has been reduced to 1, passes through the turbulent part in a full state, the powder is sufficiently cooled both in terms of time and temperature, and is not exposed to heat. Being able to continue thermal spraying at a constant temperature equal to that of the projectile means that there is no distortion in the sprayed coating, and it has become possible to easily and efficiently obtain high-quality metal coatings of high-melting point metals. Therefore, for metals with a melting point below 1000℃, the thermal spraying ability can be doubled and molded products of unlimited thickness can be obtained.
A double that boasts the highest quality and quantity ever. Ejector method low temperature metal spraying method.

[Brief explanation of drawings]

Figure 1 shows the jet angle of the jet air stream of an electric wire thermal spray machine and the deposition state of the sprayed metal particles in a longitudinal cross-sectional view, and Figure 2 shows the state of the air stream at the time of arrival on the surface of the object to be sprayed. The heat distribution in the airflow axis is expressed by color density. FIG. 3 is a longitudinal sectional view showing the thermal spraying machine of the present invention in an operating state. 1 is a thermal spray tube, 2 is a lapper-shaped wall body, 4 is a compressed air supply pipe, 5 is an annular injection port body, 7 is a conductor tube, 8 is a thermal spray wire, 9 is a conductive terminal, 10 is a plate-shaped holder, 12 is a feed roll, 18 is an annular jet nozzle, 19 is a low-pressure atomosphere, 20 is a confluence of jet airflows, 21 is a blowing airflow, 23 is an arc, 27 is a case, 31 is a high-pressure atomosphere (compressed airsphere), 40 has multiple micro-injection orifices,
50 is a control tube that spreads out at the end, 51 is a plurality of atmospheric vents and see-through holes bored in the control tube that spreads out at the end, 52 is a metal solution, 53 is a blowing air stream of a conventional machine, 54 is an object to be irradiated, and 55 is this thermal spraying machine. , 60 is a conical jet air flow, 66 is an atmospheric ventilation passage, A is a thermal spray deposit from a low-temperature spray jet, B is a hot spray deposit from a previous machine,
C is heat distribution.

Claims (1)

[Scope of Claims] 1. A plurality of large and small through holes are provided at one end of the airflow control tube that surrounds the jet airflow, and a jet airflow is formed from an annular injection port provided at the internal axis toward the other end. The metal solution, which is fed into the inner vacuum sphere of the conical shape from the bottom direction together with the atmosphere, is splintered into dendritic shapes and solidified by cooling at the injection gas confluence section at the tip of the sphere, as well as being accelerated. A high-density, low-temperature mixed airflow consisting of a large amount of air flowing into the vacuum space created between the outside of the shape and the inner wall of the control tube that spreads outward, and the jet airflow, further increases the degree of cooling of the solidified metal particles and cools the solidified metal particles. A double type characterized by measuring radiation from the other end of the control tube that spreads out at the end. Ejector method low temperature metal spraying method. 2. A diverging control tube of arbitrary length and thickness with multiple viewing windows and ventilation holes is compatible with the axial screw provided at the front end of the thermal spraying tube and is screwed onto the head of the thermal spraying tube. The double according to claim 1. Ejector method low temperature metal spraying method. 3. Claims 1 and 2, characterized in that the temperature of the blown air stream is reduced by the intake atmosphere due to the ejector action that occurs between the inner wall of the conical injection air stream and the inner wall of the control tube that spreads outward. Double as stated. Ejector method low temperature metal spraying method.