JPH0227992Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a cooling jig for pipe welding, which is used to cool a high-temperature heated portion of a butt weld of titanium, high alloy steel, etc., for example.

It goes without saying that titanium and high-alloy steel (such as austenitic stainless steel) have a strong affinity for oxygen, hydrogen, etc. at high temperatures. To prevent contamination, it must be sealed, isolated from air, and cooled until the temperature drops to a certain temperature.
By the way, when conventionally welding a steel pipe over its entire circumference while rotating, in addition to applying an argon gas seal to the heated part with a welding torch, not only for first-layer welding but also for welding the second layer and beyond, Seal is also done with argon gas,
In addition, a large amount of argon gas is flowed to the back side (inside the pipe) of the surface to be welded to create an argon gas atmosphere and perform back sealing, thereby blocking air inside and outside the steel pipe and cooling it.

However, the conventional welding method described above requires a large amount of expensive inert gas to seal and cool the heated part by flowing an inert gas such as argon gas for a long time, and also requires a large amount of expensive inert gas. Not only does this create an oxygen-deficient environment around the work area, making it difficult to breathe and poses a work hygiene problem, but the low cooling ability of the inert gas causes distortion during welding and requires a long cooling time. Therefore, continuous welding was impossible.

It is also possible to seal and cool the welded part by allowing the fluid to remain in contact with the welded part as a coolant during welding, but simply allowing the fluid to remain in the welded part will not provide the cooling function and the welding characteristics may deteriorate. It has been proven that it cannot be guaranteed.

This invention was developed in view of the above points.In other words, this invention uses a fluid as a refrigerant with a large cooling capacity instead of an inert gas to provide a certain flow rate to the pipes being rotated during welding. By spraying it on the welding area to seal the high-temperature heating area of the welding area from the air and cooling it at the same time, it is possible to significantly reduce the amount of expensive inert gas used and prevent the generation of high-temperature inert gas. An object of the present invention is to provide a cooling jig for pipe welding that enables continuous welding without requiring cooling time.

Therefore, in order to achieve this purpose, the cooling jig for pipe welding of this invention includes a cooling conduit that guides the refrigerant into the pipe to be welded, and a cooling jig that is installed in the cooling conduit and directs the refrigerant guided by the cooling conduit to the welding part. a blowout nozzle for spraying at a predetermined flow rate toward the back surface of the refrigerant; one and the other shielding members provided on both sides of the blowout nozzle to form a retention space for the refrigerant together with the inner surface of the welded pipe; In the pipe welding jig, the pipe welding jig is provided with a discharge path for discharging the refrigerant that has undergone heat exchange at the welded part from the retention space, and the blowing nozzle is directed toward a part of the welded part in the circumferential direction of the pipe to be welded. The shielding member is configured to rotate with respect to the blow-off nozzle as the pipe to be welded rotates during welding.

This invention will be explained below with reference to an illustrated embodiment.

Figure 1 shows the cooling jig for pipe welding (hereinafter referred to as the cooling jig) according to this invention, and Figures 2 and 3 show the cooling jig for pipe welding (hereinafter referred to as the cooling jig).
The figure shows that this cooling jig is used for pipes T and T as pipes to be welded.
It shows the state where it is inserted near the butted weld W.

The pipes T, T as the pipes to be welded may be made of high alloy steel such as austenitic stainless steel or high nickel steel, or may be made of, for example, titanium.

First, to explain the cooling jig, it has a cylindrical shape with one end open as shown in FIG.
For example, a discharge pipe 1 as a refrigerant discharge pipe for discharging cooling water, a cooling conduit 2 which is inserted and held in the discharge pipe 1 along the axial direction and guides the cooling water from the outside to the vicinity of the welded part W, A rotating discharge joint pipe 3 which is rotatably attached to the other closed end of the pipe 1 and discharges the cooling water in the discharge pipe 1 to the outside, and a cooling water on the side opposite to the cooling water inlet 2a of the cooling conduit 2. A cylindrical tank 4 is fixedly installed on the discharge port 2b side and has an opening connected to the cooling conduit 2, and a cylindrical tank 4 is provided protruding from the outer periphery of the tank 4 to direct the cooling water in the tank 4 to the inner surface of the welded part W vertically above. A blow-off nozzle 5 is formed into a disc shape from a flexible material such as a silicone material, and is rotatably and detachably attached to the tank 4 with its diameter direction perpendicular to the axial direction of the discharge pipe 1. Shielding gasket 6 as a shielding member
and a shield as the other shielding member, which is formed into a disk shape from a flexible material similarly to the shielding packing 6 and is removably fixed to the outer periphery of the discharge pipe 1 so as to face the one of the shielding packings 6. and a diameter D of the shielding gaskets 6 and 7.
is larger than the inner diameter d of the tubes T, T.

As shown in FIGS. 4 and 5, the cooling conduit 2 is rotatable with respect to the discharge pipe 1, and there is a liquid-tight space between the closed surface 1a of the discharge pipe 1 and the cooling conduit 2 that penetrates the closed surface 1a. Seal S ₁ is interposed. Further, the joint part 3a of the rotary discharge joint pipe 3 is slidably attached to the outer periphery of the discharge pipe 1 via a liquid-tight seal _S2 . The rotary discharge joint pipe 3 and the discharge pipe 1 are communicated with each other through discharge holes 1b formed at equal intervals around the circumference.

The blow-off nozzle 5 has a large number of nozzle pipes 8 led out from arbitrary locations on the outer peripheral surface of the tank 4, as shown in FIGS. 6 and 7. The ejection opening 8a of each nozzle pipe 8 is widened into an elliptical shape, and the opening area of the ejection opening 8a is larger than the cross-sectional area of the pipe in the middle, and each ejection opening 8a is arranged in the axial direction of the tank 4. They are assembled in a line in the orthogonal direction, that is, in the direction along the welded portion W of the tubes T, T, to form one blowout nozzle 5. In addition, this spout opening 8
The open ends of a are arranged on the circumference of a radius R concentric with the axial center of the tank 4, as shown in FIG.

Next, the rotary joint 9 to which one of the shielding gaskets 6 is removably attached is shown in FIGS. 3 and 8.
Mounting member 1 fixed to tank 4 as shown in the figure
0 is rotatably engaged. That is, the rotation joint 9 is inserted into the insertion hole 10a of the mounting member 10, and the engagement groove 9a formed along the entire circumference of the rotation joint 9 has a half-shaped engagement fixed to the mounting member 10 side. The fitting member 11 is engaged with the shielding gasket 6 which is integral with the rotating joint 9.
is rotatable with respect to the tank 4.

Note that the discharge section 1 between the discharge pipe 1 and the cooling conduit 2
c and the rotary discharge joint pipe 3 constitute a cooling water discharge path. FIG. 10 also shows a torch Tch for welding to the welded part W of the tubes T, T, a filler rod B, and a cylindrical cover C in which argon gas is blown and sealed in order to after-seal the welded part W. It shows. Furthermore, as shown in FIG.
is placed on rotating support members R, R on a fixed base Z, and is a so-called rotary tube in which the welding operation is performed using a torch Tch fixed vertically upward while rotating the tubes T, T, which are the tubes to be welded. be.

Next, the operation of the above configuration will be explained.

To explain the case of welding rotatably arranged tubes T and T together, as shown in Fig. 10, cover C is attached to the butt part of tubes T and T, and argon gas is continuously blown into the welded part. After-sealing of W is performed, and back-sealing of the welded portion W is performed by continuing to blow argon gas into the tubes T and T to create an argon gas atmosphere. In other words, the weld W is completely sealed by the above-mentioned afterseal and backseal, and in this state, while rotating the tubes T, a torch is applied from vertically above.
Using Tch and filler rod B, further welding is performed over the entire circumference of the welded portion W of the tubes T and T. Incidentally, during this welding process, argon gas is blown out from the torch Tch.

Next, in the above-mentioned single-layer welding, after the welded part W is cooled by the after-seal, the cover C is removed and the cooling jig of this invention is inserted into the pipes T, T.

That is, as shown in FIG. 11, by inserting a cooling jig into the tubes T, T against the elasticity of the shield gaskets 6, 7, the shield gaskets 6, 7 and the tubes T, T
A cooling water retention space S is formed between them. After positioning the cooling jig so that the blow-off nozzle 5 is directed vertically upward and facing the upper side of the welding part W, the cooling water is supplied at a water pressure of 4 to
4.5Kg/cm ² was introduced into the tank 4 from the cooling pipe 2 and released from each nozzle pipe 8, and while the pipes T and T were rotating together, using the torch Tch from which argon gas was released and the filler rod B. Then, a second layer of welding is applied to the welded portion W from above the tubes T, T downward over the entire circumference of the tubes T, T. At this time, the shielding gaskets 6 and 7 are rotated in the same direction as the pipes T and T are rotated, but the cooling conduit 2, discharge joint pipe 3, and tank 4 are fixed and the blow-off nozzle 5 is constantly welded. It can be oriented vertically where the weld is located.

In addition, the torch Tch and the blowout nozzle 5 are always opposed to each other across the weld W, and the discharged cooling water cools the high temperature heating area of the weld W during welding, and then the cooling water remains in the retention space. After convection at S, the water is drained to the outside through the discharge part 1c, the discharge hole 1b, and the rotary discharge joint pipe 3. In other words, when heat exchange occurs between the heat input from welding and the cooling water in the heated area on the back side of the weld W, a certain amount of the cooling water is convected at a predetermined flow rate and efficiently cools the high temperature heated area of the weld W. You will be able to do so. In this case, the heat input for welding is different from burner heating, etc., and is a spot heating, which is considered to be different from the concept of heat exchange such as a heat exchanger or a heating furnace. As an example, when boiling water in a pot, it is heated for 1 minute with a gas burner,
It is natural that the temperature of the hot water will be higher with a gas burner when it is locally heated for one minute, such as when welding. However, the latter is probably locally
The temperature will exceed 100℃, causing local boiling. To prevent this, a certain amount of water convection is required, and the flow rate, flow rate, pipe T, material of T, etc.
Wall thickness, cooling water temperature, etc. have a major influence on this.

Therefore, by exchanging heat in the weld W while causing a certain amount of cooling water to convect at a predetermined flow rate as described above, the temperature of the cooling water will not exceed 100°C.
There is no possibility of gas contamination occurring on the back surface of the weld W.

In addition, each nozzle pipe 8 of the blow-off nozzle 5 has a large opening area because the blow-off opening 8a is widened into an elliptical shape, so that when inserting and positioning the cooling jig into the pipes T, the positioning is difficult. Even if the T and T are deviated by, for example, about 10 mm to 40 mm in the axial direction, the cooling water can be reliably sprayed toward the weld W.

Note that a single fan-shaped nozzle may be considered instead of the plurality of nozzle pipes 8 as the shape of the blowout nozzle.
With this type of nozzle, when the cooling water flow rate increases,
Since the water curtain may become thin and spray unevenly on a part of the nozzle, the water may not be sprayed uniformly over the entire nozzle nozzle, and it may not be possible to reliably spray cooling water onto the weld W. It is preferable that the blow-off nozzle is composed of a plurality of nozzle pipes 8.

The third and subsequent layers may be welded in the same manner as the second layer welding described above, but after-sealing using cover C is not necessary for welding the second and subsequent layers.
A seal with argon gas from the torch Tch is sufficient. Further, although this embodiment has been described with reference to manual welding work, it goes without saying that automatic welding work can also be performed in a similar manner.

Next, a second embodiment of this invention will be described with reference to FIG. 13. Note that the same reference numerals are given to the same parts as in the first embodiment, and the explanation thereof will be omitted.

In the cooling jig of the second embodiment, a blowing nozzle 105 is provided in the middle of a cooling conduit 102, and shielding packings 106 and 107 are fixed to the cooling conduit 102. Therefore, during welding work, when the pipes T, T are rotated, the shielding packing 10
6, 107, the cooling water is guided from the sliding and fixed cooling conduit 102 to the blowing nozzle 105 and sprayed on the welding part W of the pipes T, T, which is being welded. The water is drained from the discharge part 101c of the discharge pipe 101, the discharge hole 101b, and the fixed discharge joint pipe 103 through the retention space S formed by the discharge pipe 107 and the pipes T, T.

Here, as an example, a basic calculation formula for titanium welding will be formulated as a model.

(1) As the amount of heat generated by welding (electrical) Q [cal] = 1/4.186ηρt η: Heat exchange coefficient ρ: Power consumption (W) t: Time 4.186: Work equivalent of heat Here, the MIG method is used as the welding method. Substituting the maximum generation conditions when (inert gas metal arc method) is adopted, and taking 0.6 as the heat exchange coefficient.
The meaning of η is the amount of heat Q' to be considered on the surface to be cooled for a heat input of Q° as shown in FIG. 14, as described below. (60% conversion was assumed as a safety estimate.) Welding conditions Current: 370 [A] Voltage: 45 [V] Welding speed: 550 mm/min (0.92 cm/
s) Filler rod: 1.6mmφ Q = 1/4.186 x 0.6 x 370 x 45 x 1 [S] = 2386 [cal] ... (2) Area to be cooled: Three times the area in the weld bead. If the maximum bead width is set to 5 mm, the required area is the product of the welding speed, i.e. 3 x 0.5 [cm] x 0.92 [cm/s] = 1.38 [cm/s] (3) Change water from 20℃ to 100℃ The required capacity V [cm ³ ]
If the flow velocity is u [cm/s], then (specific heat 1cal/
°C] Q=V×(100−20)=80V =80×1.38×u … ∴From the formula Q=2386 [cal]=80×1.38×u ∴s=21.6 [cm/s] ≒0.2 [m/s] ] becomes.

From this result, in the above case, the flow rate of the cooling water must be at least 0.2 [m/s] or higher. Since tap water generally has a flow rate of 0.6 to 1.5 [m/s], tap water pressure can be used as is as a refrigerant.

By the way, in the above-mentioned embodiment, the first
After welding the layers, welding was performed using the jig of the present invention, but the method is not limited to this, and the second layer can be welded using the first layer welding method shown in Fig. 10, and the third layer and subsequent layers can be welded. Of course, welding may be performed using the jig of the present invention. Further, in the above embodiment, the welding of titanium tubes T, T was described, but when welding stainless steel high alloy steel tubes, the first
In the single-layer welding shown in Figure 0, there is no need to perform after-sealing using cover C, and sealing can be performed only with argon gas emitted from torch Tch.

Furthermore, oil or the like may be used as a refrigerant in addition to cooling water. Furthermore, if the shielding packing is formed of a plurality of split packings, and the shielding packing can be made to have a reduced or expanded diameter, the jig of the present invention can also be used for welding pipes T, T having different diameters. Can be used.

As explained above, according to this invention, both shielding members are configured to be rotatable with respect to the blowing nozzle directed toward a part of the circumferential direction of the tube. Therefore, when the pipe to be welded is welded along the circumferential direction while rotating, even if the shielding member rotates in the same direction as the pipe, the refrigerant guided into the pipe to be welded by the cooling conduit is not discharged by the blow-off nozzle. It is always sprayed at a predetermined flow rate toward the back side of the welded part during welding, and the high-temperature region heating part can be efficiently cooled while being sealed from the air. Additionally, if the refrigerant is sprayed vertically upward when the pipe rotates, welding can always be performed downward rather than upward, making welding work easier and improving workability. .

In addition, since the present invention has a configuration in which the refrigerant that has undergone heat exchange at the welded part is discharged to the outside of the pipe from the discharge path, the total welding time and cooling time can be adjusted at least after welding the second or third layer. Since it was necessary to continuously flow an expensive inert gas as an afterseal and a backseal for several hours, there is no need to use an inert gas as a backseal.Moreover, titanium welding eliminates the need for an afterseal, so an inert gas can be used as an afterseal. In addition to significantly reducing the amount of gas used, it also reduces the generation of high-temperature inert gas, improving the occupational health environment.Also, since it uses a refrigerant with a higher cooling capacity than inert gas, it has a large cooling effect. This saves time and therefore allows for continuous welding, which was impossible when using an inert gas.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the cooling jig for pipe welding according to the invention, FIG. 2 is a side view showing the cooling jig inserted near the welded part of the pipe, and FIG.
A sectional view of the cooling jig inserted into the pipe, FIG. 4 is an enlarged view of the vicinity of the cooling conduit, and FIG. 5 is a sectional view of the same.
Figure 6 is a sectional view showing the blow-off nozzle and tank, Figure 7 is a plan view of the same, Figure 8 is a sectional view of the vicinity of the rotation joint of the waterproof packing, and Figure 9 is the work of rotating and welding the pipe. FIG. 10 is a side sectional view showing the welding of the first layer, FIG. 11 is the side sectional view showing the welding of the second and subsequent layers, FIG. 12 is the explanatory drawing showing the cooling water distribution state, and FIG. The figure shows the second version of this invention.
FIG. 14, a side sectional view showing the cooling jig of the embodiment, is a perspective view of a welded part for explaining the amount of heat generated by welding. T, T...Pipe, 2...Cooling conduit, 5...Blowout nozzle, 6, 7...Shielding gasket as one and the other shielding member, 1c, 3...Discharge part and rotating discharge constituting the discharge path joint tube.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A cooling conduit that guides a refrigerant into the pipe to be welded, and a cooling conduit installed in the cooling conduit to spray the refrigerant guided by the cooling conduit toward the back side of the welded part at a predetermined flow rate. a blow-off nozzle for the blow-off nozzle; one and the other shielding members provided on both sides of the blow-off nozzle to form a retention space for the refrigerant together with the inner surface of the welded pipe; In the pipe welding jig, the pipe welding jig includes a discharge passage for discharging the water from the retention space, the blowing nozzle is provided to face a part of the circumferential welded part of the pipe to be welded, and the shielding member is configured to weld the welding space. A cooling jig for pipe welding, characterized in that it is configured to rotate with respect to the blowing nozzle as the pipe to be welded rotates during construction. (2) The cooling jig for pipe welding according to claim 1 of the utility model registration claim, wherein the blowing nozzle is formed so as to always be directed vertically upward as the pipe to be welded is rotated and welded. . (3) The pipe welding cooling jig according to claim 1, wherein the blowout opening of the blowout nozzle has an opening area larger than the cross-sectional area of the intermediate pipe. (4) A cooling jig for pipe welding according to claim 1, in which cooling water is used as the refrigerant.