JP2566466B2 - Welding method for fastening members - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention uses a welding member, which is directly or indirectly coated with a metal base material such as steel, stainless steel, or aluminum, with an arc as a fastening member. The present invention relates to a method for welding a fastening member that is welded together.

(Prior Art) Generally, the coating of paint on steel members, stainless members, aluminum members, etc. is made for the purpose of protecting the appearance and the base material. For example, in the case of arc stud welding of threaded studs, threadless studs, headed studs, deformed steel bar studs, etc., since no arc is generated from the coating film, the surface of the member to be welded 1 as shown in FIG. 9 is used. A part of the coating film 3 coated on the surface 2 is physically scraped off by using a grinder or the like to form and expose the bare ground portion 4, and then the flux 6 provided on the tip of the stud 5 is exposed.
Was brought into contact with the bare ground 4 and a welding current was applied thereto, and immediately after that, the stud 5 was slightly pulled up to generate an arc and stud welding was performed.

Also, as shown in FIG. 10, when spot welding was performed using a covered arc welding rod with a threaded bolt 5A for attaching a grating to the pedestal steel material 7, a part of the coating film 3 on the back surface of the weld was burned. Since a burnt portion 8 is formed, repair painting was performed later.

(Problems to be Solved by the Invention) In the prior art shown in FIG. 9 described above, the coating film 3 on the welded portion must be removed in advance to weld dozens or hundreds of studs. However, there is a drawback in that it requires a great deal of trouble and increases the cost.

In some cases, it may be impossible to remove the coating film 3 in a narrow place, and in such a case, there is a problem that it is difficult to weld the stud itself.

Furthermore, in the conventional technique shown in FIG. 10, repair painting is required, but depending on the site, the work of repair painting is dangerous and impossible, or even if it is possible, sufficient repair painting is not possible. It was sometimes difficult to do.

The present invention has been made in view of these conventional techniques, and an object of the present invention is to provide a method for welding a fastening member on a coating film of a member to be welded which has been painted.

(Means for Solving the Problems) In order to achieve the above-mentioned object, in the present invention, a cone-shaped or needle-shaped electrode element capable of piercing a coating film on one end surface of a fastening member to break the coating film. And a gas generating agent as flux is attached to the periphery of the electrode element, and the electrode element pierces and breaks the coating film to bring it into pressure contact with the metal base surface and then through the welding gun. An arc is generated to perform arc welding of the fastening member.

(Operation) The electrode element of the fastening member chucked to the chuck of the welding gun is pressed against the painted member to be welded, and the coating film is pierced and broken to bring it into contact.

After that, a subtle welding current is applied through the welding gun to the fastening member,
Immediately after flowing to the electrode element and the member to be welded, the electrode element, that is, the fastening member, is immediately pulled up slightly to generate an arc, and the gas generating agent as a flux is thermally decomposed by the arc heat to generate carbon dioxide gas, which is peeled off by this gas pressure. The coating is blown off on the part that is easy to perform, and a part of the member to be welded is melted and then the fastening member is pressed to perform arc welding on the member to be welded.

(Embodiment) In the following embodiments, substantially the same parts are designated by the same reference numerals.

In the embodiment shown in FIGS. 1 to 4, P is a welding power source device, which is connected to a welding gun R via a power cable Q. The welding power source device P has a built-in converter for converting single-phase AC power into DC power. Reference numeral 10 is a member to be welded as a base material which becomes a metal base, and a column or plate is formed of a steel member, a stainless member, an aluminum member or the like, and a paint 11 is directly or indirectly coated on the surface thereof to form a molten film 11A. Has been formed. Reference numeral 12 denotes a fastening member, and in the present embodiment, a threaded stud 12A having a threaded portion 13 formed on the outer circumference is shown. Reference numeral 14 designates one electrode element projecting substantially on the central axis of one end surface of the stud 12A with a screw. The stud 12A is clamped by the chuck of the welding gun R and pressed in the direction of the arrow A, as described above. The molten metal film 11A is pierced and pierced to make contact with the welded member 10 as the base metal.
After passing a welding current between the welding target and the member 10 to be welded, the arc is blown by slightly pulling it up.

The flow rate l of the electrode element 14 is used in the range of 1.5 mm to 6 mm as measured from the welding surface portion 15 of the threaded stud 12A serving as the fastening member 12, but is preferably in the range of 2 mm to 5 mm.

Further, the diameter D of the stud 12A is used in the range of 3 mm to 25 mm, but it is preferably used in the range of 6 mm to 16 mm.

Therefore, in practice, the length l of the electrode element 14 and the diameter D of the stud 12A are variously combined to obtain the optimum value.
G is a gas generating agent as a flux.
It is attached to the weld surface 15 around the periphery of the. The gas generating agent G is a substance that generates an inert gas such as carbon dioxide at a relatively low temperature, for example, sodium bicarbonate (NaHCO ₃ ) and aluminum (Al) as a binder and is kneaded with the epoxy resin at a constant ratio. There is.

Thus, the gas generating agent G is thermally decomposed by arc heat to generate carbon dioxide gas, and this gas pressure scatters a part of the coating film 11A and functions as an inert gas for preventing oxidation, thereby welding. Let it be done smoothly.

 16 is a ferrule and 17 is a weld.

The embodiments shown in FIGS. 5a-5h show variously shaped studs as the fastening member 12, of which only a few are listed. Therefore,
FIG. 5a shows a stud 12B with head 18 and without screws,
FIG. 5b shows a stud 12c with a flange 19 and having a threaded portion 13 in the inner hole 20, FIG. 5c shows a stud 12d with a through hole 21 in the lateral direction, and FIG. Shows a deformed rod-shaped stud 12e that is continuously attached in a zigzag manner with a ridge 21 for improving the bite with
FIG. 5e shows an L-shaped unthreaded stud 12f,
FIG. F shows a V-shaped stud 12g, FIG. 5g shows a specially shaped stud 12h, and FIG. 5h shows a plate-shaped specially shaped stud 12i.

In short, there are various shapes even if they are called studs (12a to 12i), and the fastening member 12 exists as a superordinate concept including these studs.

The embodiment shown in FIGS. 6a and 6b shows the case where there are a plurality of electrode elements 14.

The embodiment shown in FIGS. 7a to 7c shows various shapes of the electrode element 14. FIG. 7a shows a conical shape which is the most frequently used shape, and FIG. 7b shows a needle. Figure 7c
Indicates a quadrangular pyramid.

There are various shapes of these electrode elements 14, and needless to say, they may be polygonal shapes such as a triangular pyramid, a pentagonal pyramid, and an octagonal pyramid, or other shapes.

The embodiment shown in FIGS. 8a to 8d shows the integral mounting relationship between the electrode element 14 and the fastening member 12. In FIG. 8a, the electrode element 14 is cut from the fastening member 12 into the same body. FIG. 8b shows a fastening member which is formed by projecting by means such as ejection.
12 and the electrode element 14 are separate bodies, and adhesive, brazing,
8C is a projection formed through an adhesive medium 22 such as soldering, and FIG. 8C is a projection formed integrally with the fastening member 12 and the electrode element 14 by screwing 23. In FIG. 3D, the fastening member 12 and the electrode element 14 are integrally formed by press-fitting fitting 24.

(Effects of the Invention) Since the present invention is configured as described above, there are special remarkable effects described below.

(A) Since the coating film is pierced and pierced by a sharp cone-shaped or needle-shaped electrode element so as to come into contact with the member to be welded, it is not necessary to scrape off the coating film with a grinder or the like as in the conventional case, and dozens or It is possible to arc-weld fastening members to hundreds of places immediately after painting, and work efficiency on site can be greatly improved.

Also, the painted portion on the back surface of the welded portion hardly burns, and repair painting is unnecessary.

(B) The gas pressure of the gas generant G decomposed by the arc heat blows off the surrounding coating film, and welding can be performed smoothly.

[Brief description of drawings]

FIG. 1 is an overall perspective view of the present invention, FIGS. 2 to 4 are enlarged views of essential parts showing the welding method of a fastening member according to the present invention in order, and FIGS. 5a to 5h are 6A to 6B are perspective views showing the difference in the number of electrode elements projecting from the fastening member, and FIGS. 7A to 7C are views showing various shapes of the fastening member. 8A to 8D are perspective views showing various shapes, and FIGS. 8A to 8D are enlarged views of essential parts showing various methods of attaching the electrode element to the fastening member. 9 to 10 show the prior art. 10 ... Welded member, 11A ... Paint film, 12 ... Fastening member, 12a
~ 12i …… Stud, 14 …… Electrode, 15 …… Welding surface,
G: Gas generating agent

 ─────────────────────────────────────────────────── --- Continuation of the front page (72) Inventor Hajime Shimoda 1-1-1, Shibaura, Minato-ku, Tokyo Inside Toshiba Headquarters office (72) Inventor Koji Hattori 1-2-2 Atago, Minato-ku, Tokyo Within OSE Co., Ltd. (56) Reference Japanese Patent Laid-Open No. 56-126081 (JP, A) Actual development 47-37926 (JP, U) Actual public 57-54932 (JP, Y2)

Claims (3)

(57) [Claims] 1. At least one sharp cone-shaped or needle-shaped electrode element capable of piercing a coating film is provided on one end surface of a fastening member, and the fastening is provided around the electrode element. After attaching a gas generating agent as a flux to the welding surface of the member, after piercing the electrode element into the coating film of the pre-painted member to be welded and breaking through the coating film to make contact with the member to be welded A welding method for a fastening member, wherein the fastening member is welded to the welded member by passing a welding current to generate an arc 2. The method for welding a fastening member according to claim 1, wherein the length l of the electrode element is 1.5 mm to 6 mm measured from the welding surface portion. 3. The length l of the electrode element is 1.5 mm to 6 mm as measured from the welding surface portion, and the diameter D of the fastening member is 3 mm to 2
The method for welding a fastening member according to claim 1, wherein the fastening member has a length of 5 mm.