JP2553897B2 - Torch for powder plasma overlay welding - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement in a torch for powder plasma overlay welding.

[Conventional technology]

The powder plasma overlay welding torch continuously supplies the powder spray material to the plasma arc ejected toward the base metal, and shields the molten pool with a shield gas.
Overlay welding is performed while weaving the surface of the base material.

As shown in FIG. 3, the conventional powder plasma overlay welding torch has a working gas supply path (c), a nozzle (d), and a nozzle (d) which are directed toward the outer peripheral side around the electrode (b) of the shaft center. A shield gas supply passage (e) and a shield nozzle (f) have a torch tip portion (a) arranged and supplied in this order, and a powder spray material supply passage (g) is provided in the nozzle (f). A cooling water passage (h) arranged and formed on the side of the working gas supply passage and cooling the nozzle (f) is arranged and formed outside the powder spray material supply passage (g).

When using the torch having such a structure, the weight speed is set so as to enable optimum overlay welding, as a matter of course.

However, the weight velocity is theoretically possible to increase the heat input amount of the plasma arc and increase the supply amount of the powder spray material supplied to the plasma arc,
In reality, there are the following problems, and it is difficult to increase the weight speed.

[Problems to be solved by the invention]

When the heat input of the plasma arc is increased, the powder spray material supply path (g) is excessively heated, so that part of the powder spray material supplied to the plasma arc is discharged to the excessively heated supply path outlet. Adhesion causes clogging of the supply path (g), resulting in poor yield of the powder spray material supplied.

Further, the powder spray material discharged from the powder spray material supply passage (g) is concentratedly supplied to the melting pool formed at the tip of the plasma arc, that is, on the base metal side, but if the supply amount is large, the melting becomes poor. .

Further, as the weight velocity increases, the shielding function of the shield gas against the molten pool that increases in size decreases, and good welding cannot be achieved.

The present invention provides a torch for powder plasma overlay welding to solve the above problems.

[Means and Actions for Solving Problems]

According to the present invention, a working gas supply passage is formed between an electrode having an axis and a nozzle surrounding the electrode and having a cooling water passage for cooling the nozzle and a powder spray material supply passage. It has a torch tip with a shield gas supply path formed between it and the surrounding shield nozzle, supplies the powder spray material to the plasma arc ejected from the arc restraint hole at the nozzle tip, and supplies the powder spray material in a shield gas atmosphere. In a powder plasma overlay welding torch capable of overlay welding on a material, a cooling water passage of a nozzle is formed at a position near a working gas supply passage, and the powder spray material supply passage is a cooling water passage. Is formed on the outside of the electrode at an angle of 30 ° to 50 ° with respect to the axis of the electrode, and the distance X to the intersection of the axis of the electrode and the axis of the powder spray material supply path is L / 2 to L / 4 ( Where L is the distance from the electrode tip to the base metal) A shield member having a lower surface opening that surrounds and houses the tip of the torch is attached to the chisel body, and the opening width Y of the shield member in the weaving direction is Y-2W ≧ 20 (where W is the weaving width). It is characterized by that.

In the welding torch of the present invention, the cooling water passage of the nozzle is provided on the working gas supply passage side, and the powder spray material supply passage is formed outside the cooling water passage. It is designed so as not to join the material supply path.

Further, the powder spray material supply path is formed with an inclination angle of 30 ° to 50 ° with respect to the ejected plasma arc, so that the powder spray material can be smoothly supplied into the plasma arc at that angle. You can Moreover, the plunge position of the powder spray material supplied at that angle with respect to the plasma arc is L / 2 with reference to the distance L from the electrode tip to the base material.
~ L / 4, which is between the middle position of the plasma arc and the upper position that is not too close to the arc restraint hole, the supplied thermal spray material is melted efficiently and surely until it reaches the molten pool. Even if the supply amount of the powder spray material is increased, it is possible to sufficiently deal with the problem.

In addition, the torch body is equipped with a shield member that surrounds the entire width of the bead on the base metal side even for weaving the torch, so the molten pool is always in a shield gas atmosphere and good overlay welding is performed. Is possible.

Here, the distance L between the electrode and the base material means the distance for obtaining a good plasma arc shape.

Position X of the powder spray material taken into the plasma arc
L / 2 to L / 4 from the electrode tip means that if L / 2 is larger than L / 2, the powder spray material taken into the plasma arc does not melt sufficiently until it reaches the melting pool, and the plasma It may not be smoothly taken into the arc, and L /
If it is smaller than 4, the semi-molten powder thermal spray material near the nozzle exit adheres to the nozzle exit and its vicinity, causing turbulence of the plasma arc.

The powder spray material supply path is inclined at 30 ° to 50 ° with respect to the axis of the electrode. If it is less than 30 °, the powder spray material supplied to the plasma arc will be scattered and the yield will increase. If the temperature drops below 50 °, the powder spray material will not be smoothly taken into the plasma arc, the spray material will be scattered, and the powder spray material will not flow out smoothly from the powder spray material supply passage. It depends.

〔Example〕

 Embodiments of the present invention will be described below with reference to the drawings.

 FIG. 1 shows a plasma overlay welding torch.

The plasma overlay welding torch (hereinafter also referred to as a torch) of this example has a heat input of the plasma arc of 160 J / mm ² or more and a weight velocity of 5 kg / hr to 20 kg / hr when the present invention is applied. It is a thing. Here, although not shown, the torch (1)
Is attached to a weaving operation device for weaving the torch (1), and although not shown, the torch (1) is a known powder spray material supply device, working gas supply device, shield gas. It is connected to the supply device, plasma arc power supply, cooling water supply device, etc.

The tip (2) of the torch (1) has a tapered tungsten electrode (10) along the axis of the torch (1), a nozzle (20) surrounding the tip of the electrode (10), and a nozzle (20). A shield nozzle (30) surrounding the (20) is provided. Further, a shield member (40) surrounding the torch tip portion (2) is provided on the body portion (3) of the torch (1).

The torch (1) is a torch-side working gas supply path (50) communicating with a working gas supply device between a portion of the tungsten electrode (10) excluding the tip portion and a torch body (5) surrounding this portion. And a torch side cooling water passage (60) communicating with the cooling water supply device is formed in the inside of the torch body (15) to form a hollow inside, and the torch side powder communicating with the powder spray material supply device is formed. A thermal spray material supply path (70) is formed so as to penetrate therethrough.

The nozzle (20) is the torch-side working gas supply path (50).
And an end portion of the electrode (10) surrounded by a tapered shape corresponding to the shape of the tip, and a lower end not enclosing the electrode (10) has an inner peripheral surface having an arc restraint hole (21). In the nozzle (20), a cooling water passage (60 ') communicating with the torch side cooling water passage (60) is formed in the inner portion along the arc restriction hole (21), and the cooling water passage (60) is formed. Outside of ′)
A plurality of powder spray material supply passages (70 ') communicating with the torch side powder spray material supply passage (70) and inclined toward an arbitrary axis extension of the electrode (10) are formed through the radial arrangement. Has been done.

The base end of the powder spray material supply path (70 ') communicates with the groove-shaped communication path (71) formed at the base end of the nozzle (20), and the torch side powder spray material supply path (70). The powder spray material supplied from the above is distributed to each powder spray material supply path (70 ') through the communication path (71). The inclination angle of the powder spray material supply passage (70 ') of the nozzle (20) is 30 ° to 50 ° with respect to the axis of the electrode (10). Further, from the tip of the electrode (10), the axis of the electrode (10) and the powder spray material supply passage (7
The distance X to the intersection with the axis of 0 ') is set to L / 2 to L / 4 with respect to the distance L from the tip of the electrode (10) to the welding base metal (100). Here, the inner diameter of the powder spray material supply passage (70 ') is preferably about 1.3 to 1.7 mm.

The nozzle (20) with respect to the torch body (5) is, for example, a male screw (51) formed on the inner surface of the torch-side working gas supply passage (50) and a male screw formed on the outer periphery of the base end of the nozzle (20). (22) is screwed together and fixed in place so that it can be easily attached and removed. Also, torch (1)
The O-ring (8) is formed inside and outside the cooling water passage (60 ′) and inside and outside the powder spray material supply passage (70 ′) on the surface facing the nozzle (20).
1) (82) (83) are provided so that the cooling water supplied from the torch body (15) to the nozzle (20) and the feed gas of the powder spray material do not leak outside.

The shield nozzle (30) includes a shield nozzle base (31) fixed to the outer periphery of the tip edge of the torch body (5), and a female screw (32) formed from the inner periphery of the shield nozzle base (31) to the tip. A shield nozzle tip (34) having a male screw (33) to be screwed is formed on the outer periphery.

The shield member (40) is a casing having a rectangular opening formed on the lower surface, and the torch body (3) is provided at an appropriate position on the top surface.
A cylindrical body (41) having an inner diameter corresponding to the outer diameter of is integrally formed. For the shield member (40) with respect to the torch body (5), the torch tip portion (2) is inserted into the cylindrical body (41), and the cylindrical body (41) and the torch body portion (3) are fixed with bolts or the like. It can be attached and removed by connecting and fixing with metal fittings (not shown). In the shield member (40), the opening width Y in the direction along the weaving of the torch (1)
Is set to Y-2W ≧ 20, which covers the entire weaving width of the torch (1). That is, as shown by the alternate long and two short dashes line in FIG. 2, the electrode (10) is directed to the bead end (A ′) of the base material (100) by weaving,
Even during welding, the other end (A ″) of the bead is positioned inside the shield member (40), and the electrode (10) is attached to the other end (A ″) of the bead as shown by the three-dot chain line in the figure. The other end (A ') of the bead is located inside the shield member (40) while being oriented and welded, and the entire width of the bead is always located inside the shield member (40).

With such a configuration, the nozzle (20), the shield nozzle tip (34) of the shield nozzle (30), and the shield member (40) can be attached to and removed from the torch body (5).

Therefore, if the nozzles (20) having various inclination angles between 30 ° and 50 ° and the nozzles (20) at different intake positions of the powder spray material with respect to the plasma arc are prepared, the welding target It is possible to perform overlay welding by selecting the optimum nozzle (20) according to the type of powder spray material.

Also in the shield nozzle (30),
It can be exchanged with various forms with different body lengths.

Furthermore, the shield member (40) can also be easily replaced with one that corresponds to various weaving widths W.

Therefore, by selecting the most suitable nozzle (20) for the overlay welding target, the shield nozzle tip (34) of the shield nozzle (30), and the shield member (40) and attaching them to the torch body (5), good overlay overlay is achieved. Welding is possible.

〔The invention's effect〕

According to the plasma overlay welding torch of the present invention, without changing the basic configuration of the conventional torch, in the conventional torch configuration,
It enables overlay welding at a weight speed that cannot be obtained. Moreover,
In the overlay welding, the powder spray material can be efficiently melted into the plasma arc, the yield of the supplied powder spray material is good, and the welding quality is also good.

Therefore, it is possible to improve the productivity by using the plasma overlay welding torch of the present invention.

[Brief description of drawings]

1 and 2 show an embodiment of the present invention, FIG. 1 is a sectional view showing a structure of a torch tip portion, FIG. 2 is an explanatory view showing a relation between a shield member and overlay welding, and FIG. FIG. 1 is a schematic cross-sectional view showing a notch structure of a conventional torch. 1: Torch, 2: Torch tip, 3: Torch body, 5: Torch body, 10: Electrode, 20: Nozzle, 30: Shield nozzle, 40: Shield member, 50: Working gas supply path, 60 ': Nozzle Cooling water passage, 70 ': nozzle powder spray material supply passage, 100: base material.

Claims (1)

(57) [Claims] 1. A working gas supply passage is formed between an axial center electrode and a nozzle surrounding the electrode and having a cooling water passage for cooling the nozzle and a powder spray material supply passage, the nozzle and the nozzle. Has a torch tip portion in which a shield gas supply path is formed between the shield nozzle and the surrounding shield nozzle, supplies the powder spray material to the plasma arc ejected from the arc restraint hole at the nozzle tip, and in a shield gas atmosphere In a powder plasma overlay welding torch capable of overlay welding on a base material, a cooling water passage of a nozzle is formed in the vicinity of a working gas supply passage, and the powder spray material supply passage is a cooling water passage. On the outside of the electrode at an angle of 30 ° to 50 ° with respect to the axis of the electrode,
The distance X to the intersection of the axis of the electrode and the axis of the powder spray material supply path is L / 2 to L / 4 (where L is the distance from the electrode tip to the base metal), and the torch barrel has , A shield member with a lower surface opening that surrounds and houses the tip of the torch is attached,
A torch for powder plasma overlay welding, wherein the opening width Y of the shield member along the weaving direction is Y-2W ≧ 20 (where W is the weaving width).