JPH081340A - Welding torch and build up welding equipment provided therewith - Google Patents

Abstract

PURPOSE:To provide a welding torch and build up welding equipment provided therewith by which a diameter of metal powder injected from each powder injection hole can be converged so as not to spread welding material to the neighborhood of welding place in executing build up welding. CONSTITUTION:The equipment is provided with a gas supply path, an electrode which is placed at the tip part of gas supply path and by which high voltage is energized to the gas supplied so as to generate plasma arc and a nozzle main body which is placed near the tip part of gas supply path and is arranged with a powder supply path to supply the metal powder for welding together with carrier gas into plasma arc. Further, the equipment is provided with a tip in which a plasma arc injecting hole 13 to inject plasma arc is formed in the center part, an annular groove 15 is formed on the surface of nozzle main body side around the injection hole 13 and plural powder injection holes 72 to inject metal powder are formed in the groove 13. The powder injection holes 72 are formed as inclined to the plasma injection hole 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a welding torch for welding a metal powder material for welding with a plasma arc to perform overlay welding on the surface of a workpiece and a overlay welding apparatus including the welding torch. The present invention relates to a welding torch suitable for overlay welding of a metal for welding onto a valve head of a valve of an air supply valve or an exhaust valve of an engine, and a overlay welding apparatus including the welding torch.

[0002]

2. Description of the Related Art Conventionally, a valve head of a valve (workpiece) of an intake valve or an exhaust valve of an internal combustion engine is repeatedly brought into contact with a valve seat at high speed, so that the valve head has high wear resistance. Is required. Therefore, as shown in FIG. 4, for example, Co- is formed on the outer edge portion of the valve head 2 of the valve 1 (hereinafter referred to as a material valve) to be overlay welded.
A welding material 3 having high wear resistance, such as a Cr-WC alloy, is overlay welded, and then the overlay weld portion 3 is subjected to machining such as grinding to obtain a desired shape. .

FIG. 5 is a cross-sectional view showing the tip of the nozzle body of the welding torch used for overlay welding. In the figure, 4 is a distributor 4a provided on the inner surface,
Gas supply path for supplying argon gas to be turned into plasma, 5
Is an electrode that is arranged at the tip of the gas supply passage 4 and applies a high voltage to the argon gas supplied by the gas supply passage 4 to form a plasma arc. 6 is a hole into which the gas supply passage 4 is inserted with the central axis A substantially frustoconical torch body head formed along, 7 is formed on the peripheral portion of the torch body head 6,
A pair of powder supply passages for supplying the metal powder to be the welding material 3 together with a carrier gas (carrier gas) such as argon, 8 is a nozzle provided so as to surround the side surface of the torch body head 6, 9 is argon gas, etc. The shield gas transport passage 10 for injecting the shield gas is a tip screwed to the tip of the torch body head 6. The tip portion 7a of the powder supply passage 7 is linearly formed so as to gradually approach the gas supply passage 4.

As shown in FIG. 6, the chip 10 has a disk-shaped chip body 11 whose central portion is a cylindrical portion 12, and the cylindrical portion 1
2, a plasma arc injection hole 13 for injecting a plasma arc is formed along the axis, and a screw portion 14 for screwing is formed on the outer peripheral portion. An annular groove 15 is formed around the cylindrical portion 12 of the chip body 11, and the groove 15 has an elliptical cross section for injecting the metal powder supplied together with the carrier gas from the powder supply passage 7. 6
One powder injection hole 16 is formed on the same circumference at equal intervals. The powder injection hole 16 is linearly formed so as to gradually approach the plasma arc injection hole 13 from the inlet side toward the outlet side.

In order to build up the welding material 3 on the outer edge portion of the valve head 2 of the material valve 1 using the above-mentioned welding torch, argon gas is supplied into the plasma arc injection hole 13 by the gas supply passage 4, and The argon gas supplied by applying a high voltage to the electrode 5 is turned into plasma to form a plasma arc. At the same time, a shield gas such as argon gas is jetted at a high speed from the shield gas transport passage 9 to shield the plasma arc so that the plasma arc does not entrain an external air flow. Next, the metal powder supplied together with the carrier gas into the plasma arc is sprayed from the powder spray hole 16 to melt the powder, and the molten metal is melted.
Build-up welding on the outer edge of. After that, the overlay welding portion 3 is subjected to machining such as grinding to obtain a desired shape.

[0006]

By the way, in the conventional welding torch, since the powder injection hole 16 is linearly formed so as to gradually approach the plasma arc injection hole 13, each powder injection hole is formed. There is a problem that the metal powders injected from 16 collide with each other and diffuse under the plasma arc injection holes 13 and the flux diameter of the melted metal particles expands. When overlay welding the welding material 3 on the outer edge portion of the valve head 2 using such a welding torch, the welding material 3 spreads around the welded portion and the welding material 3 is wasted and the spread welding is performed. Material 3
A machining process is required to remove the metal, especially when expensive metal powder is used, the decrease in the yield of the metal material rebounds to the cost of the product, making it difficult to reduce the cost of the product. appear.

The present invention has been made in view of the above circumstances and is capable of converging the diameter of the flux of the metal powder ejected from each powder ejection hole. Therefore, in the case of overlay welding. Another object of the present invention is to provide a welding torch in which the welding material does not spread around the welded portion and a build-up welding apparatus including the welding torch.

[0008]

In order to solve the above problems, the present invention employs the following welding torch and a overlay welding apparatus equipped with the welding torch. That is, the welding torch according to claim 1 includes a gas supply path for supplying a gas to be plasmaized
An electrode that is arranged at the tip of the gas supply path and applies a high voltage to the gas supplied by the gas supply path to form a plasma arc, and a metal powder for welding that is arranged near the tip of the gas supply path. A nozzle body provided with a powder supply path for supplying the gas into the plasma arc together with a carrier gas, and a plasma arc injection hole for injecting a plasma arc is formed in a central portion of the nozzle body. An annular groove is formed on the one main surface of the nozzle body side around the plasma arc injection hole, and a plurality of powder injection holes for injecting welding metal powder into the plasma arc are formed in the groove. And a powder injection hole of the chip is formed at a twisted position with respect to the plasma arc injection hole.

A welding torch according to a second aspect is the welding torch according to the first aspect, wherein the projection of the powder injection hole on the bottom surface of the tip is inclined with respect to the radial direction of the plasma arc injection hole. It is characterized by doing.

A welding torch according to a third aspect is the welding torch according to the first aspect, wherein at least the tip of the powder injection hole is formed in a spiral shape with respect to the plasma arc injection hole. It is characterized by that.

The overlay welding apparatus according to a fourth aspect of the present invention is an apparatus for melting a metal powder for welding by a plasma arc to perform overlay welding on a surface of a workpiece, which holds the workpiece. And a welding torch according to any one of claims 1 to 3, wherein the welding torch is configured to rotate the plasma arc injection hole of the tip. It is characterized in that it is arranged so as to face a position where overlay welding of a workpiece held on a table is to be performed.

[0012]

In the welding torch according to claim 1 of the present invention, the powder injection hole of the tip is formed at a position twisted with respect to the plasma arc injection hole, so that the welding metal supplied together with the carrier gas is supplied. The powder is jetted in the direction of a twist position with respect to the central axis of the plasma arc to form a swirling flow. Therefore, the welding metal powder supplied by the generation of the swirling flow is guided and converged on the central axis of the plasma arc. As a result, there is no risk that the metal powder melted during the overlay welding will spread around the welded portion, and the supply yield of the metal powder is improved. Further, the thickness and area of the overlay of the weld overlay are made uniform, and the quality of the product is improved. Further, a machining process for removing the metal powder is also unnecessary, and the cost of the overlay welded product can be reduced.

Further, in the welding torch according to the present invention, the projection of the powder injection hole on the bottom surface of the tip is inclined with respect to the radial direction of the plasma arc injection hole, so that it is supplied together with the carrier gas. The welded metal powder is jetted obliquely to a position close to the central axis of the plasma arc to form a swirling flow having a small flux diameter. Therefore, the metal powder for welding supplied by the generation of the swirling flow is quickly guided and converged on the central axis of the plasma arc, and the metal powder melted during the overlay welding is spread around the welding location. There is no possibility of spreading, and the supply yield of the metal powder is further improved. Further, since the variation in the supply amount of the metal powder in the plasma arc is further reduced, the thickness and area of the overlay of the overlay welding portion are made more uniform, and the quality of the product is further improved.

Further, in the welding torch according to the present invention, at least the tip of the powder injection hole is formed in a spiral shape with respect to the plasma arc injection hole, so that the welding gas is supplied together with the carrier gas. The metal powder is jetted into the plasma arc so as to draw a spiral shape and becomes a swirling flow having a small flux diameter. Therefore, the metal powder for welding supplied by the generation of the swirling flow is quickly guided and converged on the central axis of the plasma arc, and the metal powder melted during the overlay welding is spread around the welding location. There is no possibility of spreading, and the supply yield of the metal powder is further improved.
Further, since the variation in the supply amount of the metal powder in the plasma arc is further reduced, the thickness and area of the overlay of the overlay welding portion are made more uniform, and the quality of the product is further improved.

Further, in the overlay welding device according to claim 4,
The plasma arc injection hole of the tip of the welding torch according to any one of claims 1 to 3 is arranged so as to oppose a position where overlay welding of a workpiece held by the rotary table is to be performed. The amount of the metal powder supplied to the position where overlay welding of the workpiece is to be increased is increased, and there is no possibility that the metal powder spreads around the welded portion. Therefore, the supply yield of the metal powder is reduced. It is possible to improve and reduce the cost of the overlay welded product. Also, by reducing the variation in the supply amount of metal powder in the plasma arc,
The build-up welded portion of the work piece has a uniform build-up thickness and area, improving quality.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A build-up welding apparatus according to an embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a front view of a build-up welding apparatus equipped with the welding torch of this embodiment. The stock valve stock means 19 for storing the stock material valve A to be built up and the valve head of the stock valve A are shown in FIG. The welding means 20 for overlay welding and the torch 25 of the welding means 20 are held with the material valve A inclined at a predetermined angle such that the valve head of the material valve A faces the torch 25, and are rotated about the axis thereof. A material valve holding means 30,
Product valve stock means 50 for storing the product valve B subjected to overlay welding by the welding means 20, and the material valve stock means 10 to the material valve holding means 3
A valve conveying means 60 for conveying the material valve A toward 0 and conveying the product valve B from the material valve holding means 30 toward the product valve stock means 50,
An operation panel 70 is provided for instructing a control system that controls the position of the welding torch 25 of the welding means 20, welding conditions such as plasma gas conditions, powder supply conditions, and rotation conditions of the material valve A.

The material valve holding means 30 is provided with a rotary table (rotary table) 31 against which the end surface of the material valve A on the valve head 2 side abuts, and a material valve A which is provided diagonally above the rotary table 31. The valve stem of the material valve A by pressing the valve stem from above from the rotary table 31.
Is provided with a valve attaching / detaching means 32 for removably holding and a valve attachment positioning means 33 for locating and attaching the material valve A substantially coaxially with the rotary shaft of the rotary table 31.

The valve attachment positioning means 33 includes a support member 34 for obliquely supporting the material valve A, an axial movement means 35 for moving the support member 34 in the axial direction of the material valve A, and the support member 34. A radial direction moving means 36 for moving the material valve A in the radial direction is provided. The valve conveying means 60 is directed from the material valve stock means 10 to the material valve holding means 30 around a point 62 of the fixed side 61, and further, the material valve holding means 30.
From the product valve stock means 50 to the product valve stock means 50, and from the product valve stock means 50 to the material valve stock means 10 so as to be swingable.
3, the rotary member 64 rotatably attached to the tip end side of the swing arm 63, and the rotary member 64 on the outer peripheral portion of the rotary member 64 at two positions sandwiching the rotary shaft of the rotary member 64. Two chuck means 65, 66 for sandwiching the valve stem of the product valve B from the side surface are provided.

The welding means 20 is provided with a guide column 21 standing upright in the vertical direction, a movable base 22 movably attached to the guide column 21 in the vertical direction, and a horizontal movement on the movable base 22. A movable table 23 that can be attached,
A bracket 24 fixed to the lower end of the moving table 23,
The bracket 24 is provided with a welding torch 25 attached to the tip end in the vertical direction, and a hopper 26 for supplying the welding torch 25 with a welding material powdered by an argon gas flow.

The rotary table 31 includes the guide columns 2
1, a swing block 37 rotatably held by a support portion 37a, a rotary table 38 rotatably attached to the swing block 37, and a swing block 37 fixed to the swing block 37.
The rotation shaft includes a motor 39 connected to the rotary table 38 via a belt 39a.

The welding torch 25 is the same as the conventional welding torch except that the tip 10 of the conventional welding torch is changed, and the other components are the same as those of the conventional welding torch. Figure 2
Is a side view showing the tip of the welding torch 25, and FIG. 3 is a plan view of the tip 71 of the welding torch 25. In the figure, 72 is formed so as to penetrate from the groove 15 of the tip 71 toward the bottom surface 73. These are powder injection holes having an elliptical cross section for injecting the metal powder supplied together with the carrier gas from the powder supply passage 7. A total of six holes are formed on the same circumference of the groove 15 at equal intervals. There is. The bottom surface 73 of the powder injection hole 72
The upper projection c is inclined at a predetermined inclination angle θ with respect to the radial direction r of the plasma arc injection hole 13. In this case, the inclination angle θ is 5 to 10 °.

Next, a method of overlay welding the welding material 3 on the outer edge of the valve head 2 of the material valve 1 using the overlay welding apparatus of this embodiment will be described. First, gas supply path 4
With this, the argon gas is supplied into the plasma arc injection hole 13, and a high voltage is applied to the electrode 5 to convert the supplied argon gas into plasma to form a plasma arc.
At the same time, a shield gas such as argon gas is jetted at a high speed from the shield gas transport passage 9 to shield the plasma arc so that the plasma arc does not entrain an external air flow. Next, the metal powder supplied together with the carrier gas into the plasma arc is sprayed through the powder spray holes 72 to melt the powder, and the molten metal is overlay welded to the outer edge of the valve head 2.

In this case, the metal powder supplied together with the carrier gas is obliquely jetted to a position close to the central axis of the plasma arc to form a swirling flow having a small flux diameter. Therefore,
Due to the generation of the swirling flow, the metal powder is quickly guided and converged on the central axis of the plasma arc. Therefore, there is no possibility that the metal powder will spread around the welded portion during the overlay welding, and the supply yield of the metal powder is improved.

Further, since the variation in the supply amount of the metal powder in the plasma arc is further reduced, the thickness and area of the overlay of the overlay welding portion 3 are made uniform and the quality of the product is improved.

After that, the overlay welding portion 3 is subjected to machining such as grinding to obtain a desired shape. As described above, it is possible to manufacture a high-quality valve in which the thickness and area of the overlay of the overlay welding portion 3 are uniform.

As described above, according to the welding torch of this embodiment, the projection c on the bottom surface 73 of the powder injection hole 72 is
Since the plasma arc injection hole 13 is configured to be inclined at a predetermined angle θ with respect to the radial direction r, the welding metal powder supplied together with the carrier gas is placed at a position close to the central axis of the plasma arc. Can be obliquely injected into a swirling flow having a small flux diameter, and the metal powder supplied by the generation of the swirling flow can be quickly guided to the central axis of the plasma arc and converged. In addition, there is no risk that the metal powder melted during overlay welding spreads around the welded portion, the yield of the metal material can be improved, and the cost of the overlay welded product can be reduced. .

Further, since the variation in the supply amount of the metal powder in the plasma arc is reduced, the thickness and area of the overlay of the overlay welding portion 3 can be made uniform and the quality of the obtained product is improved. Can be made.

Further, according to the overlay welding apparatus having the welding torch of this embodiment, the plasma arc injection hole 13 of the tip 71 of the welding torch 25 is held on the rotary table 31 by the valve head of the material valve A. Since it is arranged so as to face the position of the overlay welding of No. 2, the supply yield of the metal powder to be supplied to the surface of the valve head 2 of the material valve A can be improved, and the valve 1 can be manufactured at a low price. can do. Further, since the variation in the supply amount of the metal powder of the tip 71 is reduced, it is possible to manufacture the valve 1 having excellent overlay thickness and area uniformity of the overlay welding portion 3.

The projection c on the bottom surface 73 of the powder injection hole 72 of the welding torch 25 of this embodiment is inclined at a predetermined angle θ with respect to the radial direction r of the plasma arc injection hole 13. However, it can be modified into various shapes other than the above-mentioned shapes. For example, even if at least the tip portion of the powder injection hole 72 is formed in a spiral shape with respect to the plasma arc injection hole 13, the same operation and effect can be achieved.

[0030]

As described above, according to the first aspect of the present invention.
According to the welding torch of the build-up welding apparatus described, since the powder injection hole of the tip is formed so as to be in a twisted position with respect to the plasma arc injection hole, the metal powder supplied together with the carrier gas. Is guided by the center axis of the plasma arc and converges, and there is no possibility that the molten metal powder during overlay welding spreads around the welding spot, and the supply yield of the metal powder can be improved. . Further, since the variation in the supply amount of the metal powder in the plasma arc is reduced, the buildup thickness and area of the buildup welded portion can be made uniform, and the quality of the product can be improved.
Further, since the machining process for removing the metal powder is unnecessary, the cost of the overlay welded product can be reduced.

Further, according to the welding torch of claim 2, since the projection of the powder injection hole on the bottom surface of the tip is inclined with respect to the radial direction of the plasma arc injection hole, it is possible to carry the carrier gas together with the carrier gas. The supplied metal powder can be rapidly guided and converged on the central axis of the plasma arc, and the supply yield of the metal powder can be further improved. Also,
Since the variation in the supply amount of the metal powder in the plasma arc is further reduced, the thickness and area of the overlay of the overlay welding portion can be made more uniform, and the product quality can be further improved.

According to the welding torch of claim 3, since at least the tip of the powder injection hole is formed in a spiral shape with respect to the plasma arc injection hole, the metal supplied together with the carrier gas is supplied. The powder can be rapidly guided and converged on the central axis of the plasma arc, and the supply yield of the metal powder can be further improved. Further, since the variation in the supply amount of the metal powder in the plasma arc is further reduced, the thickness and area of the overlay of the overlay welding portion can be made more uniform, and the product quality can be further improved. .

According to another aspect of the present invention, there is provided a weld overlay welding apparatus, which is an apparatus for melting a metal powder for welding by a plasma arc to perform overlay welding on a surface of a workpiece. The welding torch according to any one of claims 1 to 3, which holds and rotates the work piece about its axis, and the welding torch, wherein the welding torch has a plasma arc injection hole of the tip. Since it is arranged to face the position to be overlay welding of the workpiece held on the rotary table, it is possible to improve the supply yield of the metal powder supplied to the surface of the workpiece, Overlay welded products can be manufactured at low cost. Further, since the variation in the supply amount of the metal powder in the plasma arc is reduced, it is possible to manufacture a product excellent in the uniformity of the buildup thickness and area of the buildup welded portion.

[Brief description of drawings]

FIG. 1 is a front view showing a build-up welding apparatus equipped with a welding torch according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing the tip of the nozzle body of the welding torch according to the embodiment of the present invention.

FIG. 3 is a plan view showing a chip according to an embodiment of the present invention.

FIG. 4 is a partially cutaway side view showing a valve on which overlay welding is performed.

FIG. 5 is a cross-sectional view showing a tip portion of a nozzle body of a conventional welding torch.

FIG. 6 is a plan view showing a tip of a conventional welding torch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 valve 2 valve head 3 overlay welding part 4 gas supply path 5 electrode 7 powder supply path 11 chip body 12 cylinder part 13 plasma arc injection hole 15 groove 71 tip 72 powder injection hole 73 bottom surface c bottom surface of powder injection hole Top projection r Plasma arc injection hole radial direction θ Tilt angle

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Shuji Noguchi 1230 Kamihidani, Okegawa City, Saitama Prefecture Mitsubishi Mate Real Co., Ltd. Okegawa Works (72) Inventor Haruyoshi Emori 1230, Kamihide Valley, Okegawa City, Saitama Prefecture Mitsubishi Mate Real Okegawa Manufacturing Co., Ltd.

Claims (4)

[Claims] 1. A gas supply path for supplying a gas to be turned into a plasma, and an electrode arranged at the tip of the gas supply path for applying a high voltage to the gas supplied by the gas supply path to form a plasma arc. A nozzle body provided near the tip of the gas supply path and provided with a powder supply path for supplying welding metal powder together with a carrier gas into the plasma arc; and a nozzle body provided at the tip of the nozzle body, A plasma arc injection hole for injecting a plasma arc is formed in the central portion, an annular groove is formed on one main surface of the nozzle body side around the plasma arc injection hole, and the groove is in the plasma arc. A tip having a plurality of powder ejection holes for ejecting the metal powder for welding is provided, and the powder ejection hole of the tip is formed at a twisted position with respect to the plasma arc ejection hole. Welding torch according to claim. 2. The welding torch according to claim 1, wherein the projection of the powder injection hole on the bottom surface of the tip is inclined with respect to the radial direction of the plasma arc injection hole. 3. The welding torch according to claim 1, wherein at least a tip portion of the powder injection hole is formed in a spiral shape with respect to the plasma arc injection hole. 4. A build-up welding apparatus for melting a metal powder for welding by a plasma arc to perform a build-up welding on a surface of a work piece, the work piece being held, and the work piece having an axis line thereof. A rotating table that rotates about a center and a welding torch according to any one of claims 1 to 3, wherein the welding torch has a plasma arc injection hole of a chip held by the rotating table. The overlay welding device, which is arranged so as to face the position where the overlay welding is to be performed.