JPS61111781A - Stud welding method - Google Patents

Abstract

PURPOSE:To equalize a welding bead by making a shield gas whose flow velocity is higher than that of the upper side of a stud flow to the lower side of the stud. CONSTITUTION:As for a torch 11, a guide vane 17 is provided on a lower side inside peripheral wall 19 of its gateway 16. In this case, the vane 17 is projected successively from the upstream side along the inside peripheral wall 19, and constituted so as to reduce successively the inside diameter of the gateway 16. A stud 12 is held by a chuck 13 and pressed against a base metal 15, a voltage is applied, and also a shield gas G is led in from a leading-in nozzle 14. As for the shield gas G, a flow velocity of a gas G2 of the lower side is made higher than a flow velocity of a gas G1 of the upper side by the vane 17. When the stud is detached and an arc is generated, a molten pool 20 trails by gravity but it is pushed up by the gas G2 of the lower side, and formed uniformly in the peripheral direction. Accordingly, a welding bead is formed uniformly.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a new stud welding method, and in particular MIG welding, in which molten metal is shielded with an inert gas such as argon or helium, to weld bolts, etc. The present invention is directed to a stud welding method that can produce a uniform weld bead when welding a stud while supporting it horizontally or laterally relative to a base material.

[Prior Art] Stud welding is generally known as a method of welding studs such as bolts, pins, pipes, etc. to a base material by implanting them into a base material by MIG welding.

As a conventional stud welding method, a technique as shown in FIG. 4 has been adopted.

As shown in the figure, a stud 2 such as a bolt is supported in a cylindrical stud welding torch 1 with one end thereof facing toward a base material 3 and the other end being gripped by a chuck 4. A voltage is applied to the stud 2 supported within the torch 1 while being attached to the base material 3. By applying voltage to the stud 2, an arc is generated between the stud 2 and the base material 3 to form a molten pool, and the stud 2 is pressed against this molten pool to be welded to the base material 3. . In order to prevent the molten metal including this molten pool from being oxidized, an inert gas such as argon or helium is supplied as a shield gas G into the torch 1, and the base metal 3 is
It will flow to the side.

A shielding gas introduction nozzle 5 is provided in the cylindrical torch 1, and the shielding gas G is supplied into the torch 1 from this nozzle 5. The shielding gas G supplied into the torch 1 flows out along the longitudinal direction of the stud 2 held by the chuck 4, surrounding or covering the stud 2.

[Problems to be Solved by the Invention] In the conventional stud welding method, the shielding gas G is supplied into the torch 1 and flows along the longitudinal direction of the stud 2, thereby bonding the stud 2 and the base metal 3. It will shield the molten metal including the molten pool created by the arc in between. By the way, when welding the stud 2 to the base metal 3 in the horizontal direction as shown in FIG.
The high-temperature liquid molten pool generated between the stud 2 and the base metal 3 hangs down in the direction of gravity, and the weld bead 6 formed between the stud 2 and the base metal 3 after welding hangs down and sticks, resulting in uneven welding. There was a problem that beads 6 were formed.

[Object of the Invention] The present invention was devised to effectively solve the problems in conventional stud welding methods.

An object of the present invention is to provide a stud welding method that can produce a uniform weld bead when welding a stud facing horizontally to a material to be welded, such as a base material.

[Summary of the Invention] In order to achieve the above object, the present invention provides a stud welding method in which a stud such as a bolt is supported by a torch and welded while being positioned horizontally to the base metal. Welding is performed by flowing shielding gas at a higher flow rate from above, and the shielding gas pushes up the molten pool that tends to droop in the direction of gravity to form a uniform weld bead.

[Example] Next, the method of the present invention will be explained in detail based on a specific example of an apparatus.

As shown in FIGS. 1 and 2, a stud welding gun 10 used in the present invention includes a cylindrical torch 11 and a chuck 1 provided inside the torch 11 to grip a stud 12.
3, a shield gas introduction nozzle 14 for supplying a shield gas such as an inert gas into the torch 11;
The guide vane 17 is opened facing the base material or the workpiece 15 of the torch 11 and is installed near the entrance/exit 16 of the stud 12.

The torch 11 is formed into a cylindrical body having an annular cross section, and an opening at one end forms an entrance/exit 16 for the stud 12 .

A chuck 13 is provided inside the torch 11 so as to be able to reciprocate in the longitudinal direction. A gripping portion 18 for gripping a stud 12 such as a bolt is provided at the tip of the chuck 13. .

Further, the torch 11 is provided with a shield gas introduction nozzle 14 for causing the shield gas to flow down along the stud 12 held by the chuck 13.

This nozzle 14 is provided so as to be located above the torch 11 when it is supported in the horizontal direction.

The torch 11 is provided with a guide vane 17 close to the inner periphery of the entrance/exit 16 thereof. This guide vane 17
is provided on the lower inner circumferential wall 19 of the torch 11, which is on the opposite side of the shield gas introduction nozzle 14 when the torch 11 is supported horizontally.

The guide vanes 17 are successively raised or protruded from the upstream side of the lower inner circumferential wall 19 in the entrance/exit 16 of the torch 11 as shown in FIGS. It is configured to sequentially reduce the diameter. Therefore, the structure is such that the shielding gas G flowing down inside the torch 11 to the inlet/outlet 16 reaches the inlet/outlet 16 and the flow velocity is increased sequentially from the upper side to the lower side.゛Hereinafter, the method of the present invention will be described.

As shown in FIG. 3, the stud 12 is gripped by the chuck 13, placed horizontally against the welded material or the base material 15, and pressed against it, and a voltage is applied. shield gas G
will be introduced. Shielding gas G introduced into the torch 11
is the entrance/exit 16 of the torch 11 by the guide vane 17.
In the vicinity, the flow velocity of the gas G2 flowing in the lower side of the torch 11 is increased from the upstream side of the shielding gas G1 flowing in the upper side of the torch 11.

Next, the stud 12 pressed against the workpiece (base metal) 15 is slightly pulled apart to generate an arc, and the workpiece (base metal)
A molten pool 20 is generated between the base material 15 and the stud 12. This molten pool 20 tends to hang down in the direction of gravity as shown by the dashed line in the figure, but as described above, the flow velocity of the shielding gas G is higher in the lower part near the entrance/exit 16 of the torch 11 than in the upper part. The molten pool 20 that is about to hang down is pushed up by the shielding gas G2 and is uniformly formed in the circumferential direction of the joint end of the stud 12, thereby forming a weld bead 21.

Further, although the guide vane 17 is configured in a fixed and streamlined manner in the illustrated example, it may also be configured to variably increase the flow velocity of the shielding gas G2 flowing from the upper side to the lower side. Of course it's a good thing.

[Effects of the Invention] As is clear from the detailed description above, the present invention provides the following excellent effects.

(1) Since welding can be performed while pressing the molten metal (pool) or metal with the shielding gas, there is no drooping phenomenon of the molten metal even in horizontal welding, and a uniform weld bead surface can be obtained.

(2) A uniform weld bead surface can be obtained even in horizontal welding simply by attaching a guide vane to the welding torch, and the structure is simple and versatile, as it can be easily adopted in existing welding machines of this type. rich in

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing a specific example of an apparatus for carrying out the method of the present invention, FIG. 2 is a sectional view taken along the IF-I line in FIG.
FIG. 3 is a schematic side sectional view for explaining the present invention in detail;
FIG. 4 is a side sectional view showing a conventional example, and FIG. 5 is a side view showing an example of a stud welded by the conventional example. In the figure, 11 is 1 to -1, 12 is a stud, and G is a shielding gas. Patent applicant: Ishikawajima-Harima Heavy Industries Co., Ltd. Representative patent attorney: Nobuo Kinutani = 9- Figure 7 μ

Claims (1)

[Claims] In the stud welding method, a stud such as a bolt is supported by a torch and welded horizontally to the base metal.
A stud welding method characterized in that welding is performed by flowing a shielding gas to the lower side of the stud at a higher flow rate than the upper side.