JPH0673150U - Arc spray gun - Google Patents

Abstract

(57) [Summary] [Object] To provide an arc spray gun for forming a good spray coating having a large adhesive strength by reducing the oxidation of molten metal particles and increasing the speed in arc spraying. [Arrangement] An inert gas nozzle 4 is provided between the wire tips 3a, 3b to prevent oxidation by forming an inert atmosphere in the arc generation portion, and an air guide 6 surrounding the wire tip and the inert gas nozzle, and an outer circumference of the air guide. An orifice ring 8 is provided to surround the arc, and compressed air is jetted toward the tip of the arc point to accelerate the molten metal and blow it onto the base material to improve flattening of metal particles on the base material and reduce bubbles. . Further, an injection nozzle 10 is provided outside the orifice ring, and a secondary air flow is formed outside the spraying flow to prevent oxidation and reduction in velocity.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention provides an arc spray gun that reduces the oxidation of molten metal particles during arc spraying and increases the spraying speed to form a sprayed coating with high adhesive strength.

[0002]

[Prior art]

 In the conventional arc spray gun, as shown in FIG. 4, a pair of wire tips 32 and 33 are attached to a guide plate 31 provided at the tip of the spray gun at an appropriate angle, and compressed air is supplied from the rear of the wire tips. The wire tip is blown out, the outer circumference of the wire tip is surrounded by a nozzle skirt 34, and the tips of the wires 35, 36 made of aluminum, titanium, chrome, etc., which are sent out through the respective wire tips in this nozzle skirt, are brought into contact with each other to create an arc. By the flow of the compressed air that is generated and blown from the rear of the arc in the direction of the arrow, the molten metal fine particles are blown onto the base material (not shown).

[0003]

[Problems to be solved by the device]

 In such a method in which metal particles atomized by an arc generated in air are blown with compressed air, an oxide film is likely to be generated on the surface of the metal particles atomized by the arc, and the spray particles are the base metal. Not only does the sprayed film easily peel off when it adheres to the arc, but the compressed air blown from behind the arc hits the arc column, impairing the pressure and limiting the speed at which particles fly. There is.

Therefore, as shown in FIG. 5 (b), when the metal particles adhere to the base material 21, the flatly extended state (lamella) 23 becomes thick, and the lamella phase is small because the diameter of the lamella is small. There is a drawback that bubbles 24 are likely to be generated between each other and in the stacking portion.

[0005]

[Means for Solving the Problems]

 Therefore, in the present invention, an inert gas nozzle is provided between the wire tips of the arc spray gun to eject the inert gas from the rear of the arc, and an orifice ring is provided outside the air guide surrounding the wire tip and the inert gas nozzle. Thus, an air ejection hole for ejecting compressed air is formed slightly ahead of the arc point.

Further, an injection nozzle is provided outside the air guide in place of the nozzle skirt, and an air hole is provided at the base of the injection nozzle to generate a secondary air flow.

[0007]

[Action]

 Therefore, the inert gas ejected from behind the arc of the wire led out from the wire tip wraps the surface of the metal particles melted by the arc to prevent oxidation, and is accelerated by the compressed air from the air ejection holes, and It is sprayed at high speed.

In addition, the secondary air flow from the injection nozzle surrounds the flow of the sprayed particles to prevent the metal particles from contacting with the base material in the air which is in a nearly stationary state, and prevents the metal from hitting the base material. Reduces particle velocity and cooling.

[0009]

【Example】

 This will be described with reference to the embodiment shown in FIGS. 1, 2 and 3. Reference numeral 1 denotes a main body, to which feed guides 2a and 2b through which the wire W is inserted are attached. 3a and 3b are wire tips at the tip of the feeding guide, 4 is an inert gas nozzle provided in close contact with the wire tips, and 5 is a guide plate which is attached to the tip of the main body 1 and holds the wire tips. 3 b and an air guide 6 surrounding the inert gas nozzle 4, and a vent hole 7 provided outside the air guide of the guide plate. Reference numeral 8 denotes an orifice ring that surrounds the outer periphery of the air guide 6 from the outside of the vent hole 7 and forms an air ejection hole 9 at its tip. The air ejection hole 9 is directed slightly ahead of the arc point A.

10 is an injection nozzle attached to the tip of the main body and having an appropriate length surrounding the arc point A, 11 is an air hole at the base of the injection nozzle, 12 is an inert gas nozzle 4 and an inert gas, for example, argon gas. An inert gas base to be supplied, 13 is a compressed air base for supplying compressed air to the compressed air chamber 14 through an air passage (not shown) inside the main body, and a reference numeral 15 is a cover mounting seat for safety.

An inert gas is supplied from the inert gas nozzle 12 to the inert gas nozzle 4, for example, an argon gas at 20 to 25 liters / min to form an inert atmosphere in front of the inert gas nozzle 4, and the compressed air nozzle 13 is provided. 7 kg / cm ² of compressed air is supplied to the compressed air chamber 14 through an air passage (not shown) in the main body 1, passes through the air hole 7 of the guide plate 5 and the gap between the air guide 6 and the orifice ring 8, Compressed air is ejected from the air ejection hole 9 toward a position slightly ahead of the arc point A, for example, 2 mm. This flow of compressed air causes the inert gas to spontaneously blow out from the inert gas nozzle due to the pressure difference.

From the feeding guides 2a and 2b, a plus 130 to 150 A and a plus 28 to 30 V plus a negatively charged wire W, for example, a Ni-Cr alloy wire, is fed, and the inert atmosphere is passed through the wire tips 3a and 3b. When they are brought into contact with each other, they generate an arc, are heated and melted, and become high-temperature metal fine particles. These metal particles are wrapped with the inert gas ejected from the inert gas nozzle 4, slightly ahead of the arc point A. It is accelerated by the flow of compressed air ejected from the air ejection holes 9 toward and is sprayed on the base material at high speed.

As shown in FIG. 5A, the molten metal particles blown onto the base material at high speed and high temperature have a strong force of colliding with the surface of the base material 21, and the flattened metal particles (lamella) 22 are uniform. The thickness is small, the surface area is large, the laminated state of the lamella is dense, the number of bubbles is small, and the oxide film is small, so that a good sprayed film having high adhesion strength is formed.

Further, if an injection nozzle 10 having an appropriate length is provided so as to surround the arc point A, the flow of compressed air causes the ejector effect from the air hole 11 at the base of the injection nozzle 2 to 2 to 2 of the compressed air. Approximately five times as much secondary air flows in to surround the flow of the spray particles and maintain the direction of the flow, while preventing the spray flow from contacting the air in a nearly static state existing with the base material. In addition, a decrease in speed and rapid cooling are reduced, and a better sprayed film is formed.

A sprayed film having a thickness of 0.5 mm is formed on a test piece having a diameter of 40 mm, and the test piece which is not sprayed is bonded with an adhesive (S / M2214 manufactured by Sumitomo 3M) and adhered by an Amsler tensile tester. As a result of the property test, the conventional gun had an average adhesion force of 4.7 kg / mm ² , but the spray film formed by the gun of the present invention has an adhesion force of 6.0 kg / mm ² . Was given.

Further, as a result of measuring the surface hardness with a Vickers hardness tester, the sprayed film by the conventional gun that generates an arc in the air was 40 Hv, but the sprayed film by the gun of the present invention was 370 Hv. Hardness was obtained.

As the inert gas, N ₂ gas, Co ₂ gas, or the like can be used in addition to the Ar gas described above. When Co ₂ gas is used, oxidation slightly increases but the hardness of the film increases. Higher results are obtained.

[0018]

[Effect of device]

 As described above, the present invention provides an inert gas nozzle for injecting an inert gas between wire tips to maintain an arc generating part in an inert gas atmosphere, and an air guide that surrounds the wire tip and the inert gas nozzle. Since the orifice ring that surrounds the outside of the air guide and forms the air ejection hole is provided, the molten metal particles are less oxidized and the thermal spray rate can be increased. Therefore, the adhesion strength with the base metal is low. Highly sprayed film with high air bubbles and few bubbles.

Further, since the arc is generated in the inert gas atmosphere, the carbon burning in the metal is small, the hardness of the sprayed film is high, and the nitrogen gas is used as the inert gas. In the case of nitriding, a harder film can be obtained. Since the spraying temperature is high, it is possible to use high-temperature refractory metals.Also, by using a composite wire in which various metal powders, ceramics, etc. are mixed in the metal shell, cermets etc. can be freely used. There are effects such as being obtained.

Further, by providing an injection nozzle and forming a large amount of secondary air flow outside the thermal spray flow, there is an effect that the oxidation of metal particles in the thermal spray flow can be further reduced and a decrease in speed can be prevented.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of the present invention, a part of which is shown in section.

FIG. 2 is a side sectional view of the embodiment shown in FIG. 1, showing a part in section.

FIG. 3 is a sectional view taken along line xx of FIG.

FIG. 4 is a plan sectional view showing a part of a conventional example.

FIG. 5 is an explanatory diagram of a sprayed film.

[Explanation of symbols]

 1 Main body 2a, 2b Feeding guide 3a, 3b Wire tip 4 Inert gas nozzle 5 Guide plate 6 Air guide 7 Vent hole 8 Orifice ring 9 Air ejection hole 10 Injection nozzle 11 Air hole 12 Inert gas mouthpiece 13 Compressed air mouthpiece 14 Compressed air Chamber 21 Base material 22,23 Lamella 24 Bubble W Wire A Arc point

Claims (2)

[Scope of utility model registration request] 1. An arc spray gun comprising a main body to which a wire feed guide is attached and a guide guide for holding a wire tip of the feed guide at a tip portion of the main body, the arc spray gun being provided between the wire tips. An inert gas nozzle provided to blow out an inert gas, a guide plate for holding the wire tip by the guide guide, an air guide surrounding the wire tip and the inert gas nozzle, and a slightly ahead of the arc point surrounding the outer circumference of the air guide. An arc spray gun, characterized in that it has an orifice ring that forms an air ejection hole that blows out compressed air toward it. 2. An arc spray gun comprising a main body to which a wire feed guide is attached and a guide guide for holding a wire tip of the feed guide at a tip portion of the main body, the arc spray gun being provided between the wire tips. An inert gas nozzle provided to blow out an inert gas, a guide plate for holding the wire tip by the guide guide, an air guide surrounding the wire tip and the inert gas nozzle, and a slightly ahead of the arc point surrounding the outer circumference of the air guide. An orifice ring that forms an air ejection hole that blows out compressed air toward the outside, and an injection nozzle of an appropriate length surrounding the arc point on the outside of the orifice ring, and an air hole at the base of the injection nozzle. Characteristic arc spray gun.