JPH1069999A - Wire thermal spraying device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance stability of arc form a wire and ensure improvement in work efficiency and product quality by employing a tip end of the wire as an anode and a non-consumption electrode as a cathode, generating an arc between both electrodes, and fusing the wire. SOLUTION: First, air is fed to a gas path 5 of a nozzle 40, and a voltage of about 50V is applied from a DC power source between two wires 21a and 21b and a non-consumption electrode chip 3a as a cathode. Next, the wires 21a and 21b in charged states is supplied into the nozzle 40, and an arc is generated between it and the chip 3a. At this time, an arc current and an arc voltage are adjusted to about 800A and about 22V, respectively. Thereby, dissolved particles in which the wires 21a and 21b are fused are ejected from a droplet path 41 of the nozzle 40 at a high speed, and thermal spraying to a processed material is started. Thus, by employing the wires 21a and 21b made of a thermal spraying material as an anode, that fusion speed is higher than that of a cathode in the case of the same current. Thereby, thermal spraying efficiency is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire spraying apparatus for spraying a material for providing heat resistance, corrosion resistance and abrasion resistance in a component of a product.

[0002]

2. Description of the Related Art Arc spraying using a wire requires corrosion resistance and abrasion resistance because the spraying material is relatively inexpensive and the spraying apparatus has a simple structure and is easy to operate. It is widely used for hardening on or near the surface of a member.

FIG. 2 shows an example of a conventional arc spraying apparatus using such a wire. In FIG. 2, reference numerals 1a and 1b denote wires made of a sprayed material, and reference numerals 2a and 2b denote wires 1a and 1b.
A positive or negative voltage is applied to each of the wires 1a and 1b by a power supply (not shown) via the power supply chips 2a and 2b. Reference numeral 3 denotes a gas nozzle for ejecting a gas for generating droplets, and reference numeral 4 denotes a cap for narrowing the spray pattern of the droplets.

At the time of a thermal spraying operation using such a thermal spraying apparatus, a positive or negative voltage is applied to each of the two wires 1a and 1b, and a wire supply device (not shown) controls the gas nozzle 3. Feed to the front, the wire 1
An arc is generated at the tips of a and 1b.

As a result, the tips of the wires 1a and 1b are melted, heated by the gas sprayed from the gas nozzle 3 and ejected as droplets, further squeezed by the cap 4, and squeezed to the workpiece (shown in the figure). G) and form a coating on the surface.

[0006]

However, in the conventional thermal spraying apparatus shown in FIG. 2, two wires 1a, 1a
Since b is divided into an anode (positive voltage) and a cathode (negative voltage), the heating phenomena at the poles are different, so that the melting rates of the wires 1a and 1b are not the same. For this reason, if the supply speed of the wires 1a and 1b is increased for the purpose of increasing the spraying efficiency, the arc from the wires 1a and 1b becomes unstable, and stable spraying cannot be performed.

Further, since the two wires 1a and 1b serving as an anode and a cathode are supplied and an arc is generated at the tip thereof, the tip positions of the two wires 1a and 1b tend to fluctuate. Therefore, there is also a problem that the stability of the arc is impaired and a desired sprayed product cannot be obtained.

The present invention has been made in view of the above-mentioned problems of the prior art, and aims to improve the stability of an arc from a wire, improve the efficiency of a spraying operation, and improve the quality of a sprayed product.

[0009]

According to the present invention, in order to solve the above-mentioned problems, a wire as a sprayed material is melted by an arc generated at the tip of the material and blown onto the surface of a workpiece. In a thermal spraying apparatus that forms a thermal spray layer, a plurality of the wires are supplied, and the tips of the wires are formed as anodes, and the non-consumable electrode disposed in close proximity to the wire is formed as a cathode. A wire spraying apparatus is proposed, wherein the arc is generated between the tip of the wire and the non-consumable electrode to melt the wire.

In the wire spraying apparatus, the non-consumable electrode is disposed at the center of the internal space of the cylindrical nozzle, and the wire is inserted into an insertion hole in an outer wall of the cylindrical nozzle. It is preferable to be mounted so that it can enter and exit in the direction of.

According to this invention, since a plurality of wires as a sprayed material are used as the anode, the temperature is higher than that of the cathode because of the collision absorption of electrons of the anode and the high current density. The melting rate on the wire side (the wire side) is higher than on the cathode side (the non-consumable electrode side), thereby significantly improving the spraying efficiency over the conventional one.

Further, by using all of the plurality of wires as anodes, the melting speed of the plurality of supplied wires becomes uniform, the arc is stabilized, and stable spraying is performed even in a high current region.

Further, since the fixed non-consumable electrode is used for the cathode, the variation in the distance from the tip of the wire on the anode side is reduced to about half that of the conventional one, and the arc can be stabilized from this aspect. The performance is improved.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be illustratively described in detail below with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only.

FIG. 1 is a sectional view of a thermal spraying torch portion of a wire thermal spraying apparatus according to an embodiment of the present invention. In FIG. 1, 4
Numeral 0 denotes a cylindrical nozzle having a droplet passage 41 opened at the tip, and a feed tip 22a,
Wires 21a and 21b, which are thermal sprayed materials, through 22b
Is inserted freely.

The wires 21a and 21b are connected to a DC power supply (not shown) via the power supply chips 22a and 22b, and a positive voltage is applied (anode) from the DC power supply. I have. Reference numeral 3a denotes a fixed non-consumable electrode tip, which is made of a material having a high melting point such as tungsten and is fixed to a water-cooled electrode holder 3b.
c. A negative voltage is applied (cathode) from the DC power supply (not shown) to the non-consumable electrode tip 3a.

The electrode holder 3b is made of a material having good conductivity and heat conductivity such as copper. 5 is the nozzle 4
The gas passage is formed in the nozzle hole 0 and through which a gas for forming a spray pattern by adjusting the flow of the droplet ejected from the droplet passage 41 flows.

When performing a spraying operation on a workpiece by the wire spraying apparatus having such a configuration, first, air is flowed into the gas passage 5 of the nozzle 40 (flow rate 20 l / min).
Two wires 2 which are the anode together with the preferred degree)
Non-consumable electrode tip 3a serving as a cathode with 1a, 21b
, A voltage of about 50 V is applied from a DC power supply.

Next, the charged wire 21
a and 21b are supplied into the nozzle 40 to generate an arc with the non-consumable electrode tip 3a. At this time, the arc current is adjusted to about 800A and the arc voltage is adjusted to about 22V.
As a result, the molten particles in which the wires 21a and 21b are melted are ejected from the droplet passage 41 of the nozzle 40 at a high speed, and thermal spraying on a workpiece (not shown) is started.

According to the experimental example of the present inventors, when the sprayed material is 18Cr stainless steel copper, the wires 21a,
The feed rate of 21b was about 30 kg / hr, and the welding efficiency was as high as 81% when the sprayed substrate was a carbon copper plate.

In the thermal spraying apparatus according to the present invention described above, the wires 21a and 21b, which are the thermal spraying material, are used as anodes, so that the impact absorption of electrons by the anodes and the high current density make the temperature higher than that of the cathodes. Therefore, when the melting rate is the same, the melting rate is higher than that of the cathode (non-consumable electrode tip 3a). As a result, the spraying efficiency is significantly improved.

Further, since all the wires 21a and 21b are used as anodes, the melting speed of a plurality of supplied wires becomes uniform, the arc is stabilized, and stable spraying is performed even in a high current range.

Further, since the fixed non-consumable electrode tip 3a is used for the cathode, the wires 21a and 21b on the anode side are used.
The fluctuation of the distance from the tip of the arc is reduced, and the arc is stabilized from this surface.

In the above embodiment, the wire 21
Although a and 21b are two, this is not limited to two.
Of course, it is also possible to use three or more lines.

[0025]

As described above, according to the present invention, by using a wire as a sprayed material as an anode, the melting rate of the wire is significantly increased as compared with the conventional wire, and the spraying efficiency is improved. This can contribute to an improvement in productivity.

Further, by using a plurality of wires all as anodes, the melting rate of each wire is made uniform, arc stability is obtained, and a fixed non-consumable electrode is used for the cathode. The variation in the distance between the two is reduced to about 1/2 that of the conventional one, and the arc stability can be obtained from this aspect. Thereby, the quality of the sprayed product is improved and the efficiency of the spraying operation is also improved.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of a thermal spraying torch part of a wire thermal spraying apparatus according to an embodiment of the present invention.

FIG. 2 is a drawing corresponding to FIG. 1 showing a conventional wire spraying apparatus.

[Explanation of symbols]

 3a Non-consumable electrode tip 3b Electrode holder 5 Gas passage 21a, 21b Wire 22a, 22b Feed tip 40 Nozzle 41 Droplet passage 42 Insertion hole

Claims (2)

[Claims] 1. A thermal spraying apparatus in which a wire as a thermal spray material is melted by an arc generated at a tip of the thermal spray material and blown to a surface of a workpiece to form a thermal spray layer. In addition to this supply, these tips form an anode, and the non-consumable electrode disposed in close proximity to the tip of the wire serves as a cathode, and the arc is provided between the tip of the wire and the non-consumable electrode. The wire spraying apparatus is characterized in that the wire is melted by causing heat generation. 2. The non-consumable electrode is disposed at the center of the internal space of the cylindrical nozzle, and the wire can enter and exit the insertion hole in the outer wall of the cylindrical nozzle in the direction of the non-consumable electrode. The wire spraying device according to claim 1, which is attached.