JPS6012154B2 - Stud welding ferrule - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to improvements in ferrules used in stud welding.

Stud welding is widely used to weld dowels or bolts to steel frames, bridges, and other heavy structures, but conventional stud welding is used to protect the welding arc and molten metal. Part of the glassy slag generated by the melting of the ferrule often entered the welded area and degraded mechanical performance.

The welding state when stud welding is performed using a conventional ferrule will be explained using FIG. 1. 1 is a stud dowel, 2 is a welding base material, 3 is a ferrule, and 4 is a weld metal.

The ferrule 3 is made of a cylindrical body having a stud through hole 3a through which the stud gibberoo passes and a reinforcement forming hole 3b for forming a cavity for forming the reinforcement. The ferrule 3 is provided with a plurality of ventilation grooves 6 in all directions in order to allow some of the gas and molten metal generated to escape.The ferrule 3 is made of a suitable binder made of powder such as Katsuragi, alumina, or magnesia. The ferrule is made of a heat-resistant material that is sintered at high temperatures and has high strength at high temperatures.When performing stud welding using this ferrule, an arc is created between the stud dowel 1 and the weld base metal 2. The welding arc is generated to melt the surface parts of both, and when both are sufficiently melted, the stud dowel is pressed against the welding base material 2 to complete the welding.In this case, the welding arc is 300
Since the temperature exceeds 0 qo, the inner surface of the ferrule 3 melts and a glassy slag 5 is generated. When the stud dowel 1 is pressed against the welding base material 2 in this state, the molten metal of the stud dowel and the welding base material 2 will protrude around the stud dowel 1, but since it is surrounded by the ferrule 3, some of it will not protrude from the groove 6. The majority of the ferrule 3 rises around the stud dowel 1 along the inner wall of the ferrule 3, forming a band-shaped extra layer 7. Here, the present inventor found from the results of numerous welding experiments that when forming the extra layer 7, the slag 5 is also scraped up, and as the extra layer 7 rises, a part of the slag 5 falls between the stud dowel 1 and the extra layer 7. It has been found that not only the thin film slag 8 is formed, but also a part of the thin film slag 8 further penetrates into the lower surface of the stud dowel 1 and forms a slag entrainment part 9 in the settling part. In this way, the thin film-like slag 8 that has entered between the stud dowel 1 and the extra layer 7 prevents the stud dowel 1 and the extra layer 7 from joining together, and makes the extra layer 7 irrelevant to ensuring the strength of the welded part. Furthermore, the slag entrapment portion 9 becomes a stress concentration area for tensile stress and bending stress, causing a decrease in mechanical strength. Figure 2 shows the fractured part when a welded part with such a slag layer is subjected to a destructive test. Stress concentration occurs at the slag entrainment part 9 shown in the figure, and fracture occurs from this part. ing. The present invention provides a ferrule in which the inside of the ferrule is stepped and the inner diameter above the central portion is larger than the inner diameter below, thereby preventing the occurrence of the thin film slag and slag entrainment in the welded portion. This is what I did.

Figures 3a and 3b show a ferrule 3 according to the present invention, which has a hole 301 with a diameter d in the lower part of its inner surface, and a hole 302 with a diameter d2 in the upper part. .

The diameters of these holes are set to be d, and a step 303 is formed at the boundary between both holes. Reference numeral 6 denotes a groove provided to release a portion of gas generated during welding.

The state in which the ferrule of the present invention is used is shown in FIGS. 4 and 5. In these figures, the structural members indicated by numerals 1 to 7 are the same as those in FIG. 15 is a ferrule holding plate; 15 is a support rod L for fixing the ferrule holding plate 14 to the stud welding gun 16; 16 is the gun body; 17 and 17' are cables and control lines for supplying power to the gun 16. Upon completion of welding, when the stud dowel 1 is pressed against the welding base metal 2, the slag generated on the inner surface of the ferrule 3 due to arc heat rises together with the molten metal, but the slag is formed by the large upper part of the ferrule 3. When the slag reaches the position of the space 11, it escapes into this space and becomes a ring-shaped slag 12. Therefore, unlike when the conventional ferrule shown in FIG. 1 is used, slag does not cover the surface of the extra layer 7, and the thin film-like slag 8 and slag entrapment part 9 shown in FIG. 1 are not generated. do not have. In addition, since the thin film slag 8 is not formed, the stud dowel and the extra metal 7 can be brought into direct contact, and as a result, the side surface of the lower end of the stud dowel 1 is secondary melted by the heat held by the extra metal 7, and the extra metal is melted. It is fused integrally with the embankment 7 to form a secondary melting section 13. As a result, no slag entrapment is formed in the welded part 4, stress concentration does not occur, and the reinforcement 7 is effective in ensuring the strength of the welded part, making it possible to obtain a stronger welded part. . By the way, as shown in Fig. 1, the conventional ferrule has a shape in which the upper part is bent, and there is a 0.0 mm gap between it and the stud gibberoo.
A gap between the 2nd and 05th fences is provided.

During welding, even if gas generated by arc heat is blown out from this gap, consideration is given to preventing outside air from entering and preventing air from coming into direct contact with the molten part. Since the cylindrical ferrule of the present invention has an open top, special measures are required for the ferrule holding plate when using this ferrule. When using a conventional ferrule, a ferrule holding plate, usually called an open hood holder, as shown in FIG. 6 is used. In the figure, 14 is a ferrule holding plate, and 15 is a support rod. Since the purpose of such a secondary ferrule holding plate is simply to position and hold the ferrule, the gap between the stud dowel and the holding plate is large, and the closing part 19 is opened toward the front in order to remove the welding gun from the stud dowel after welding. It is provided. When such a ferrule holding plate is used in the ferrule of the present invention and welded, gas generated by arc heat rapidly escapes upward, making it impossible to obtain a sufficient shielding effect. Therefore, when using the ferrule of the present invention, for example, a ferrule holding plate 14 is prepared, the appearance of which is shown in FIG. 7 in use. This ferrule holding plate 14 consists of a main piece 18 fixed to the tips of support rods 15, 15 fixed to the stud welding gun body 16, and an insertion piece 19 attached to this main piece. . The main piece 18' has a through hole 20 through which the stud dowel 1 passes through, and a fan-shaped notch 21 that is continuous with the through hole in the approximate center of the main piece 18'. The whole is formed into a substantially fan shape so that it fits together.
The insertion piece 19 is rotatably attached to the main piece 181 by a hinge 22, and is attached to the notch 21 by a releasable stop 23.
It is designed to remain connected to the The inner surface of the insertion piece 19 is formed into a cylindrical shape so that the inner peripheral surface of the through hole 20 provided in the king piece is continuous to form a stud through hole 24 surrounding the outer periphery of the stud gibberoo. As shown in the figure, when the notch 21 is closed with the insertion piece 19, there is no gap between the outer peripheral surface of the stud dowel 1 and the stud through hole 24.
．． A uniform narrow gap d of about 2 to 0.5 ribs is formed. On the lower surfaces of the main piece 18 and the insertion piece 19, there is an annular groove 25 that is continuous with each other and concentrically surrounds the stud through hole 24 when the insertion piece is fitted into the notch 21 as shown in the figure. Arc-shaped grooves 26 and 27 are provided, and the annular groove 25 iron-fits the upper end of the ferrule 3 to hold the ferrule 3. (See Figure 5.
) Gas generated by arc heat during welding is trapped between the ferrule 3 and the ferrule holding plate 14, and a part of it is ejected from the gap d between the stud dowel and the ferrule holding plate to prevent outside air from entering. When welding is completed, the welding gun is pulled upward and separated from the stud dowel, but since the stud dowel is usually provided with a head 101, in that case, the stopper 23 is removed and the insertion piece 19 is opened. to remove the ferrule holding plate 14 from the stud dowel 1. In the above embodiment, the dowel material having the head was stud welded.
When welding a columnar stud without a head,
It is sufficient to provide only a circular hole that can form a narrow gap between the ferrule holding plate and the outer periphery of the stud without providing a notch in the ferrule holding plate.

As described above, according to the ferrule of the present invention, welding can be performed without causing slag entrainment in the welded part, and in addition, the excess part can be effectively used to maintain strength, resulting in reliable stud welded parts. It has the advantage of dramatically improving sexual performance.

Further, the ferrule of the present invention has the advantage that manufacturing is facilitated because the upper part of the through hole opens upward with an inner diameter larger than the inner diameter of the reinforcement forming hole.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of a welded part when using a conventional ferrule, Fig. 2 is a cross-sectional view showing a damaged state of the port section, and Fig. 3 a and b respectively show the structure of the ferrule of the present invention. A perspective view and a sectional view, FIG. 4 is a front view showing the state when the ferrule of the present invention is used, FIG. 5 is a sectional view showing details of the welded part in FIG. 4, and FIG. 6 is a conventional ferrule. Fig. 7 is a perspective view of the ferrule support plate when using the ferrule support plate of the present invention. FIG. 1... Stud dowel, 2... Welding base material, 3... Ferrule, 303... Step, 5... Slag, 7... ... Remaining thickness, 11 ... Space created by the step, d, ... Inner diameter of the lower hole, 1 ... Inner diameter of the upper hole, 14 ... Ferrule retention Plate, 25... annular groove. Many boxes, many Z boxes, many boxes, many boxes, many boxes.

Claims (1)

[Claims] 1. In a stud welding ferrule consisting of a cylindrical body having a stud through-hole, the lower part of the through-hole of the cylindrical body has a desired inner diameter corresponding to the outer diameter of the stud applied as an overlay forming hole; The ferrule for stud welding has a structure in which the upper part of the hole has an inner diameter larger than the inner diameter of the above-mentioned reinforcement forming hole and opens upward while maintaining the large inner diameter.