JPH04284978A - Plasma powder cladding torch - Google Patents

Abstract

PURPOSE:To improve operability of build up welding by reducing the width of a torch tip external shape in the first direction to orthogonally cross the central axis of an arc hole and enlarging the width thereof in the second direction to orthogonally cross the central axis of the arc hole and the first direction. CONSTITUTION:A nozzle member 10 forming the arc hole 2 through which a plasma arc generated between a main electrode 1 and base metal is passed on the central part is provided. A powder supply path 5 to supply powder into the above-mentioned plasma arc, a gas supply path 9 to supply gas to cover the above-mentioned plasma arc and cooling water supply paths 11a and 11b to supply cooling water to cool a torch are provided. The width of the torch tip external shape is reduced in the first direction Hs to orthogonally cross the central axis Cent of the arc hole and it is enlarged in the second direction Ls to orthogonally cross the central axis of the arc hole and the first direction. Consequently, when a large width part is abutted on deposited metal and build up welding is difficult, the abutment is avoided and welding can be performed by directing a small width part to the deposited metal.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma powder overlay torch that performs overlay welding using powder.

0002

BACKGROUND OF THE INVENTION Overlay welding has been conventionally performed to improve metal surfaces (wear resistance, heat resistance, corrosion resistance, etc.). That is, in the overlay welding process, powder metal is supplied into a plasma arc column, and while it is melted, it is injected onto the welding surface along with the plasma arc, and the weld metal is used to overlay the metal surface. The torch used for this is, for example, JP-A-1-218
It is disclosed in Japanese Patent No. 772.

The tip of this type of torch is shown in FIG. 5, for example.
Alternatively, it has a structure as shown in FIG. Note that Figure 5 (
b) and FIG. 6(b) show the bottom surfaces of FIG. 5(a) and FIG. 6(a), respectively. In each figure, 51 is a tungsten electrode;
52 is a plasma gas, 53 is a powder, 54 is a powder carrier gas, 55 is a cooling water, 56 is a shielding gas, 57 is a plasma arc column, 58 is a weld metal, 59 is a base material, and 60 is a nozzle member. In the torch shown in FIG. 5, the nozzle member 60 is equipped with a plasma injection hole and a plurality of powder supply holes 60a formed around the plasma injection hole, and the powder 53 is transferred to the powder carrier gas supply path 31 along with the carrier gas 54. The powder is supplied into the plasma arc column 57 from the powder supply hole 60a through the powder supply hole 60a. There is a ring-shaped space surrounding the arc hole between the lower opening of the powder carrier gas supply path 31 and the upper opening of the powder supply hole 60a. In the torch shown in FIG. 6, two nozzles 61 and 62 are provided concentrically, and the inner nozzle 61 narrows and injects a plasma arc, and from the gap between the two nozzles, powder 53 together with carrier gas 54 is ejected. is supplied into the plasma arc column 57.

0004

[Problems to be Solved by the Invention] Incidentally, in this type of plasma powder overlay torch, the torch tip portion 50
is cylindrical, and its bottom surface is as shown in Fig. 5(b) and Fig. 6(b).
As shown in the figure, it has a circular shape with the tungsten electrode 51 at the center.

Therefore, as shown in FIG. 7, a cylindrical shield cap 63 similar to the torch tip portion 50 shown in FIG. 5 or FIG. When performing overlay welding from the S direction, the shield cap 63 is attached to the weld metal 58.
As a result, the distance l0 between the torch tip portion 50 and the point P becomes large, and as a result, overlay welding becomes impossible or difficult. Welding metal 5 to torch tip portion 50
8 is relatively large, this is not a problem, but when it is small as shown in FIG. 7, it becomes a problem, and a torch tip portion with a small shape must be used.

The object of the present invention is to improve the operability of a plasma powder overlay torch.

[0007]

[Means for Solving the Problems] The present invention provides a main electrode (1)
The arc hole (
2) includes a nozzle member (10) formed in the center, and a powder supply path (5) for supplying powder into the plasma arc.
, 6, 6a), a gas supply path (9, 9a) for supplying gas covering the plasma arc, and a cooling water supply path (11a, 11a) for supplying cooling water for cooling the torch.
11b), in a plasma powder overlay torch comprising:
The outer shape of at least the tip (100) of the torch is aligned in the first direction (H) perpendicular to the central axis (Cent) of the arc hole (2).
s), the width is narrow, and the central axis (Cent
) and a second direction (Ls) perpendicular to the first direction (Hs).
Let's make it wide.

Note that symbols in parentheses indicate corresponding elements in the embodiments described later.

[0009]

[Operation] Adjust the outer shape of at least the tip (100) of the torch to the first
The width is narrow in the direction (Hs), and the center axis of the arc hole (2) (
Cent) and the second direction (Ls) perpendicular to the first direction (Hs).

[0010] Therefore, when the overlay welding process is difficult due to the wide part coming into contact with the weld metal, the tip (100) of the torch is rotated 90 degrees.
By directing the narrow part toward the weld metal, overlay welding can be performed while avoiding contact, improving operability.

Other objects and features of the invention will become apparent from the following description of embodiments with reference to the drawings.

0012

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of a tip portion 100 of a plasma torch for powder overlay welding according to the present invention. Note that (a) in Figure 1
1 shows a longitudinal section, and FIG. 1(b) shows a bottom surface. Further, FIG. 2 shows a longitudinal section of the plasma torch tip portion 100 shown in FIG. 1 viewed from the side.

The plasma torch tip portion 100 is secured to the torch handle by a tightening cap. A rod-shaped electrode 1 made of tungsten is arranged at the center of the torch, and this electrode 1 is fixed to the torch by a chuck (not shown). Tip 1a of electrode 1
has a sharp shape, and the tip 1a is located at the center of the arc hole 2 formed at the center of the nozzle member 10. 3 is a ceramic centering stone, which positions the electrode 1 at the center of the nozzle member 10. Plasma gas is supplied from the outside through the space between the electrode 1 and the chuck, and is guided to the arc hole 2 of the nozzle member 10 through the hole 3a formed in the centering stone 3. This plasma gas is ionized by arc discharge between the electrode 1 and the base material (not shown), forming a high-temperature plasma arc flow.

Powder and a powder carrier gas for transporting the powder are supplied from outside the torch, pass through a powder tube (pipe) 5, and pass through two holes (powder carrier gas) formed in the nozzle member 10. The gas is injected from the lower opening 6a through the gas flow path (6) toward the plasma arc flow, and is injected into the plasma arc flow. The injected powder is melted by the heat of the plasma arc flow, becomes molten metal, and covers the welding surface on the base metal.

The shielding gas 7 passes through the space 9 between the nozzle member 10 and the stainless steel shielding cap 8 and is injected from the exhaust port 9a so as to cover the plasma arc flow, thereby shielding the welding surface from the outside air. .

In addition, in order to prevent the nozzle member 10 from overheating, the cooling water is supplied from the outside of the torch to the hole (for the outward path of the cooling water) 11.
a and is supplied to the groove 12 formed in the nozzle member 10. The groove part 12 is formed concentrically, and the cooling water supplied to the groove part 12 from the hole 11a flows through the hole (for the return path of the cooling water) 11.
is returned to the outside of the torch through b.

As shown in FIG. 1(b), in this embodiment,
The powder carrier gas flow path 6 and the powder tube 5 are aligned with the central axis C of the electrode 1.
ent (from the front side of the paper to the back side), and the central axis C
It is arranged along the straight line Ls direction, which is a direction perpendicular to ent. Also, the cooling water holes 11a and 11b are also straight lines Ls.
It is arranged parallel to the powder tube 5 along the direction. Further, the shield gas exhaust port 9a is formed in a crescent shape symmetrically to the straight line Ls. That is, the powder carrier gas, cooling water, and shielding gas are supplied from a direction substantially perpendicular to the central axis Cent (straight line Ls direction), and are supplied from a direction perpendicular to the straight line Ls and the central axis Cent (straight line Hs direction). I will try not to let it happen.

As a result, the plasma torch tip portion 10
The shape of 0 is made into a plate shape (the bottom surface is a substantially rectangular parallelepiped) so as to have the minimum width in the direction of the straight line Hs. The shield cap 8 covering the plasma torch tip portion 100 is also plate-shaped accordingly. In addition, in this embodiment, the shield cap 8 is
The ratio of the width A in the direction of the straight line Ls to the width B in the direction of the straight line Hs was set to 2:1.

Note that 13 is a threaded insert tip (
It is made of copper) and has four grooves 13a carved on its outer periphery. The pin 14a of the attachment/detachment tool 14 is fitted into the groove 13a when the insert tip 13 is attached or detached, and by rotating the attachment/detachment tool 14, only the insert tip 13 can be attached or detached from the plasma torch tip portion 100 without particularly removing the shield cap 8. shall be. This is shield cap 8
Since the shield cap 63 has a plate shape, it is effective in cases where it is troublesome to remove the shield cap 63 compared to the cylindrical shield cap 63 shown in the conventional example.

FIG. 3 shows a case in which build-up welding is performed from the direction of arrow S at point P of the deposited metal 58 using the plasma torch tip portion 100 shown in FIG. The weld metal 58 is the same as that shown in FIG. 7 for the conventional example.

During the overlay welding process, the shield cap 8
If the wide part of the plasma torch comes into contact with the deposited metal 58 as shown in the conventional example (FIG. 7) and the overlay welding process is difficult, the plasma torch tip part 100 is rotated 90 degrees, that is, as shown in FIG. As shown in , the narrow portion of the shield cap 8 is directed toward the weld metal 58 . As a result, the distance l (<l0) between the torch tip portion 100 and the point P becomes relatively small, so that overlay welding can be performed without using another torch tip portion having a smaller shape.

In the above embodiment, the nozzle member 10 has two holes (powder carrier gas flow path) 6, one on the left and right, but as shown in FIG. 4 type holes (powder carrier gas flow paths) 16 may be formed.

In this embodiment, as shown in FIG. 1(b), the torch tip portion 100 is formed into a substantially rectangular parallelepiped by cutting off both sides of a semicircle with respect to the straight line Ls. It is also possible to have a shape (approximately a rectangular parallelepiped + one side) in which only one part is cut off. In this case, the powder carrier gas flow path 6, the powder tube 5, and the cooling water holes 11a and 11b do not necessarily need to be arranged along the straight line Ls direction, but may be slightly shifted toward one side. Good too.

[0024]

According to the present invention, the outer shape of at least the tip (100) of the torch is adjusted to the center axis (C) of the arc hole (2).
The width is narrow in the first direction (Hs) perpendicular to the arc hole (2), and the width is narrow in the first direction (Hs) perpendicular to
Since it is wide in the second direction (Ls) perpendicular to s),
During overlay welding, if the wide part comes into contact with the weld metal and the overlay welding is difficult, use the tip of the torch (1
00) by 90 degrees and directing the narrow part toward the weld metal, overlay welding can be performed while avoiding contact, improving operability.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view of the main parts of an embodiment of the present invention, and FIG. (b) is a bottom view.

2 is a longitudinal cross-sectional view of the tip portion 100 of the plasma powder overlay torch shown in FIG. 1, viewed from the side.

[Figure 3] Plasma torch tip portion 100 shown in Figure 1
FIG. 3 is an external view showing how overlay welding is performed using the welding process.

FIG. 4 is a bottom view showing another embodiment of the present invention.

5 is an enlarged view of the tip of a conventional plasma powder overlay torch, and FIG. 5(a) is a vertical cross-sectional view of the front end of the plasma powder overlay torch, FIG. (b) is a bottom view.

FIG. 6 is an enlarged view of the tip of another conventional plasma powder overlay torch, and FIG. 6(a) is a vertical cross-sectional view of the front end of the plasma powder overlay torch. FIG. 6(b) is a bottom view.

7 is an external view showing how overlay welding is performed using the plasma torch tip portion shown in FIG. 5. FIG.

[Explanation of symbols]

1: Electrode (main electrode)
2: Arc hole (arc hole) 3: Centering stone 3
a: Hole 5: Powder tube (powder supply path)
6: Hole (powder supply path) 6a: Lower opening (powder supply path) 7:
Shield gas 8: Shield cap
9: Space (gas supply path) 9a: Exhaust port (gas supply path) 10
: Nozzle member (nozzle member) 11a, b: Hole (cooling water supply path) 12: Groove 13: Insert chip
14: Detachment tool 14a: Pin
16: Hole 58: Welded metal
59: Base material 100: Torch tip (tip)

Claims (1)

[Claims] 1. A nozzle member having an arc hole formed in the center through which a plasma arc generated between a main electrode and a base material passes; a powder supply path for supplying powder into the plasma arc; In a plasma powder overlay torch equipped with a gas supply passage for supplying gas to cover the arc and a cooling water supply passage for supplying cooling water for cooling the torch, the external shape of at least the tip of the torch is narrow in a first direction perpendicular to the central axis of the arc hole and wide in a second direction perpendicular to the central axis of the arc hole and the first direction. Meat torch.