JPH0244941Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention is a tack welding jig for shield gas arc welding to reduce the amount of shield gas used when tack welding, for example in butt welding of stainless steel pipes. Regarding.

(Prior art) As is well known, in metal butt welding, the base metal is processed to form a V-shaped or U-shaped groove, and after the grooves are aligned, tack welding is performed, and then main welding is performed. A root interval of a size corresponding to the welding conditions is provided between the base metals.

Temporary attachment methods include fixing between base materials using temporary attachment members such as bridges and pieces.
When welding difficult-to-weld base materials such as stainless steel,
Since the above method may cause defects to the base material, it is required to temporarily attach the base material directly to the groove. In this case, temporarily attach it to the groove,
Next, main welding is carried out on top of the weld, but since defects due to welding cannot be allowed to exist in the tack-welded part, it is necessary to completely shield the welded part during tack-welding to protect the deposited metal from the atmosphere. The first example of a means to completely shield the temporary attachment part is to seal a part of the groove on the back side of the base material with shielding gas, and the second example is to fill a part of the groove on the back side of the base material with shielding gas when the base material is a pipe. There are two types: one in which the entire length of the pipe is sealed, and a third example in which the shielding gas is sprayed directly from the back side of the groove with a nozzle.

(Problems to be Solved by the Invention) However, the first and second examples of the conventional means described above have the disadvantage that they consume a large amount of expensive shielding gas such as argon gas, resulting in high contact costs. However, in the third example, the shielding of the temporarily attached part is not sufficient, and the prevention of defects in the base material is unsatisfactory.

An object of the present invention is to provide a jig for temporarily attaching welded joints that does not cause welding defects while reducing the consumption of expensive shielding gas.

(Means for solving the problem) The jig body 1 has a bank 3a around a rectangular plate that is wider than the root spacing between the base materials M and M and has a length sufficient to protect the temporary attachment part. A caul plate 3 formed into a tray shape, support rods 4 and 5 for attaching the caul plate to a base material, a support piece 6 fixed to the tip of the holding rod 5, and a grip portion erected thereon. It consists of 7.

The tip of the support rod 4 is provided with a holding portion 4a through which the support pin 2 is inserted to hold the jig main body 1 to the base material, and the support pin is freely insertable and removable.

(Function) In the present invention, the backing plate 3 is brought into contact with the temporarily attached portion of the base materials M, M, and both sides of this backing plate are in contact with the back side of the base material, and the backing plate 3 is provided at the tips of the support rods 4, 5. When the support pin 7 inserted through the holding portion 4a and the support piece 6 come into contact with each other on the outer periphery of the base material, this serves as a fulcrum and fixes the backing plate in a predetermined position. To attach and detach the present invention to the base materials M and M, the support pin 2 is attached to the holding part 4a.
The user inserts and removes the base material from the root gap of the base material by grasping the grip part 7.

Next, the tacking work is done by injecting shielding gas from the tip of the torch and generating an arc from the electrode. When the torch is brought close to the groove and the shielding gas is injected onto the part to be tacked, the shielding gas is spread between the roots. It flows out to the back side through . At this time, the outflow of the shield gas is blocked by the backing plate 3,
It is reflected and stays around the tack joint, making it possible to obtain a defect-free weld.

(Example) Examples of the present invention will be described below with reference to the drawings. In this example, the base material is a stainless steel pipe,
This article describes the case of construction using the TIG welding method.

The present invention consists of a main body 1 and a support pin 2 for fixing the main body in contact with the inside of base materials M, M.
Both require heat resistance and corrosion resistance, so they are made from stainless steel.

As shown in the first figure, the main body 1 has support rods 4 and 5 erected at both ends of a backing plate 3, and a holding portion 4 provided on the outside of the support rod 4 for attachment to base materials M and M.
A is fixed to the outer end of the support rod 5, and a T-shaped support piece 6 is fixed to the outer end of the support rod 5. On the extension of the support rod 5, a gripping portion 7 is further erected at an angle such that it is located along the outer periphery of the tube.

The backing plate 3 is a rectangular thin plate with a circularly curved surface that is gentler than the inner radius of the base materials M, so that a gap C of 2 to 3 mm is created when both ends come into contact with the inside of the base materials. It is shaped like a basin with an embankment around it.

The support rods 4 and 5 are made of stainless steel rods with a diameter smaller than the root spacing, and the holding portion 4a is formed by rounding the tip of the support rod 4, leaving a length necessary for attachment to the base materials M and M. There is. The other support rods 5 also have support pieces 6 fixed orthogonally to their tips.

The support piece 6 is made from a stainless steel rod with a larger diameter than the support rods 4 and 5, and its length is equal to that of the backing plate 3.
It is made larger than the width of .

The grip part 7 is made of a stainless steel rod having the same diameter as the support piece 6, and has a length of about 80 to 120 mm, which is convenient for holding by hand.

The support pin 2 is made from a stainless steel rod having a diameter larger than that of the support rod 6 and the grip part 7, and has a thinner lower end 2a and a ring 2b for a grip at the upper end. The diameter of the support pin 2 is such that it can be inserted into the hole of the holding portion 4a of the support rod 4.

Next, how to use the present invention will be explained. As shown in FIG. 3, the welding points of the stainless steel pipes M, M, which serve as the base metals, are formed into a V-groove, and fixed so as to maintain a predetermined root spacing.

Next, grasp the grip part 7 of the main body 1, and insert the support rod 4 (the tip part), the backing plate 3, and the support rod 5 into the base material in this order from the root interval, so that the backing plate abuts against the temporary attachment part. Then, the holding part 4a at the tip is made to protrude from the root gap, and inserted into the hole formed there.
It is attached to the base materials M by inserting the support pins 2. At this time, a gas release gap C of 2 to 3 mm is provided between the base materials M and the backing plate.

If you approach the TIG welding torch T from the outside of the base metals M and M where the caul plate 3 is attached, and while blowing argon gas for shielding, generate an arc between the electrode D and the base metal to melt the weld metal. Temporary attachment is completed. At this time, the shielding gas tries to flow inside the base materials M, M through the root interval, but
It is blocked by the caul plate 3 and accumulates between the caul plate and the base material to protect the welded part.

Note that the present invention is not limited to temporary attachment for construction of stainless steel pipes, but can be applied as a jig for temporary attachment when using shielding gas such as aluminum pipes.

(Effects of the Invention) According to the present invention, since it is possible to effectively utilize an expensive shielding gas such as argon, it is possible to easily obtain a defect-free and high-quality temporarily attached part. Furthermore, it is small and lightweight and can be easily attached to and detached from the base material, so it contributes to improvements in welding work, especially piping work.

[Brief explanation of drawings]

1 is a front view, FIG. 2 is a front view showing an attached state, FIG. 3 is a side view showing an attached state, and FIG. 4 is a sectional view showing a state of temporary attachment. 1...Main body, 2...Support pin, 3...Packing plate,
3a...Bank, 4, 5...Support rod, 4a...Holding section, 6...Support piece, 7...Gripping section.

Claims (1)

[Scope of claim for utility model registration] A backing plate with a bank formed around one side of a rectangle, and support rods erected at both ends of the backing plate,
A holding part with an insertion hole is formed at one end of the support rod, a support piece is fixed at right angles to the end of the other support rod, and a gripping part is connected to the support rod. A tacking jig for shielded gas arc welding, comprising: a jig body; and a support pin that is inserted through the holding portion to fix the jig body to a base material.