JPS6310220Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention melts the tip of the stud by arc heat or resistance heat between the workpiece and the stud, and then surrounds the stud tip from the outside air when press-welding it to the workpiece. This relates to porcelain tubes for stud welding (hereinafter referred to as ferrules).

Using a porcelain tube with grooves with approximately equal spacing on the circumference of the ferrule that is in contact with the workpiece, it is possible to attach the diameter to large structures such as buildings and bridges (hereinafter referred to as the workpiece).
If you try to horizontally weld studs with a diameter of 16 mm or more, the larger the diameter of the stud, the more molten metal will be at the tip of the stud due to arc heat or resistance heat generation, and the molten metal will be moved by gravity during melting. Since the tendency of the molten metal to flow downward increases, defects such as insufficient reinforcement and undercuts occur above the welded part after solidification of the molten metal, making it impossible to obtain sufficient mechanical strength of the welded part.

Therefore, when horizontally welding studs with a diameter of 16 mm or more, a groove is provided only on the upper half of the circumference of the ferrule on the side that contacts the workpiece to release the gas generated during welding. A ferrule has been proposed that attempts to prevent the outflow of molten metal without providing a groove on approximately half the circumference.

However, the grooves provided on the circumference of the ferrule were originally provided at approximately equal intervals on the circumference in contact with the workpiece, and were designed to evenly release the gas generated during arc generation. There is. Therefore, if welding is performed in a horizontal position using a ferrule that has grooves only on approximately half of its circumference as described above, it is possible to prevent molten metal from flowing out from the grooves below. Since the generated gas is released only upward, the release of the gas from below is delayed and the molten metal begins to solidify, and the gas is trapped in the solidified molten metal, and the residual gas causes porosity in the welded part. Stable mechanical strength may not be obtained due to sputtering caused by a transient increase in the internal pressure below, or insufficient pressure when pressing a stud with a molten tip to the workpiece. It had some serious flaws.

Therefore, in an attempt to reduce these defects to some extent, a method is used in which a smaller number of grooves are provided on approximately the lower half of the circumference of the surface of the ferrule in contact with the object to be welded than the number of grooves on the upper half of the circumference. Furthermore, as previously proposed by the present applicant, a ferrule has been proposed in which the cross-sectional area of each groove on the lower half of the circumference is smaller than that of the groove on the upper half of the circumference. It is certain that such an improved ferrule eliminates a considerable portion of the above-mentioned drawbacks and has certain effects. However, in these improved ferrules, the sum of the cross-sectional areas of the grooves on the lower half of the circumference is essentially smaller than that of the upper grooves, so the generated gas is released uniformly from the grooves on the circumference. The problem of not doing so has not been resolved.

The present invention aims to uniformly release the gas generated during welding from around the circumference, and since the generated gas has pressure, it has the property of being released even from grooves with a small cross-sectional area. By taking advantage of the fact that metal has the property of preventing metal from flowing out due to surface tension and the property of metal flowing out due to gravity, it is possible to weld the ferrule in a horizontal position with multiple grooves. The cross-sectional area of the groove provided on the lower half of the circumferential surface, based on the position where the left and right sides are approximately symmetrical, is
By making the cross-sectional area smaller than the cross-sectional area of the grooves provided on the upper half of the circumference, the surface tension overcomes gravity and prevents the molten metal from flowing out. A stud whose diameter is equal to or greater than the sum of the cross-sectional areas on the circumferential side of the grooves provided in the stud, so that the generated gas is released almost uniformly from the circumference, thereby preventing the occurrence of welding defects. It provides porcelain tubes for welding.

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 is a plan view of a typical ferrule.
FIG. 2 is a cross-sectional view taken along the line A--A in FIG. FIG. In FIGS. 3 and 4, the symbol V-V is a vertical line passing through the center O of the ferrule, H-H is a horizontal line passing through the center O of the ferrule, and the symbols 1 to 8 and 1 to 14 are the lower half circumference. The grooves 21 to 25 are grooves provided in the upper half circumference, and the cross-sectional area of each inner circumferential side of the grooves 21 to 25 provided in the upper half circumference is equal to the groove 1 provided in the lower half circumference. It is more than twice the cross-sectional area of each of the inner peripheral sides of grooves 1 to 8 and grooves 1 to 14.

In FIG. 3, the cross-sectional area of grooves 1 to 8 provided on the lower half circumference is compared to that of grooves 21 to 24 provided on the upper half circumference.
By reducing the cross-sectional area to, for example, 1/2 or less, the surface tension of the molten metal overcomes gravity and prevents the molten metal from flowing out, and the number of grooves provided on the lower half of the circumference is 8. The number of grooves provided on the upper half of the circumference is twice as many as four. As a result, the sum of the cross-sectional areas of the grooves provided in the upper half circumference and the sum of the cross-sectional areas of the grooves provided in the lower half circumference are approximately equal, and the gas generated in the upper half circumference and the lower half circumference is approximately uniform. Since it is released, uniform filling and melting can be obtained.

FIG. 4 shows a second embodiment of the phenol of the present invention. In the embodiment shown in FIG. 3 above, the sum of the cross-sectional areas of the grooves in the lower half circumference and the sum of the cross-sectional areas of the grooves in the upper half circumference are approximately equal, but the cross-sectional area of the grooves in the lower half circumference is 1/1/1 that of the grooves in the upper half circumference. 2 or less and the resistance of the generated gas passing through the unit cross-sectional area in the groove is large, so the gas pressure generated on the inner surface of the lower half of the circumference tends to increase transiently.
Therefore, as shown in Figure 4, the number of grooves provided on the lower half circumference is actively increased so that the sum of the cross-sectional areas of the grooves on the lower half circumference is larger than the sum of the cross-sectional areas of the grooves on the upper half circumference. In particular, it is desirable to suppress a transient increase in the gas pressure on the inner surface of the lower half circumference.
In the figure, in the upper half of the circumference, 5 grooves 21 to 25 are provided approximately every 30 degrees, while in the lower half of the circumference, a total of 14 grooves, 1 to 7 and 8 to 14, are provided approximately 10 degrees each. It is set for each degree. Even if the cross-sectional area of each groove on the upper half circumference is approximately 2.5 times that of each groove on the lower half circumference, the sum of the cross-sectional areas of the grooves on the lower half circumference is larger than the sum of the cross-sectional areas of the grooves on the upper half circumference. .

Furthermore, by providing one or two protrusions indicated by the symbol P in FIG. 1 on the outer periphery of the ferrule shown in FIGS. 3 and 4, when the stud and ferrule are attached to a welding gun, It is possible to automatically position the groove on the lower half of the circumference, which has a small cross-sectional area, accurately downward.

As described above, even if the ferrule of the present invention is used to horizontally weld large-diameter studs, the cross-sectional area of each groove on the lower half of the circumferential surface that contacts the workpiece of the ferrule is The cross-sectional area of the grooves is made smaller to allow the surface tension of the molten metal to overcome gravity and prevent the molten metal from falling and flowing out. The total cross-sectional area of the grooves provided in the half circumference is approximately equal to that of the upper half circumference, or by actively increasing it, so that the gas generated from the upper half circumference and the gas generated from the lower half circumference are released almost uniformly. As a result, it is possible to obtain good overlay and uniform melting, which is of great practical benefit.

[Brief explanation of drawings]

Fig. 1 is a plan view of a general ferrule, Fig. 2 is a cross-sectional view taken along the line A--A in Fig. 1, and Figs. It is a figure which shows the inner peripheral surface of the side which contacts an object.

Claims (1)

[Scope of utility model registration request] In a stud welding porcelain tube provided with a plurality of grooves passing through the inner and outer circumferential sides of a circumferential surface in contact with the material to be welded, the direction when the porcelain tube is welded in a horizontal position, The cross-sectional area of the grooves provided on the lower half of the circumferential surface is smaller than the cross-sectional area of the grooves provided on the upper half of the circumferential surface, with reference to a position where the plurality of grooves are substantially symmetrical on the left and right sides, and A porcelain tube for stud welding, wherein the sum of the cross-sectional areas on the inner circumferential side of the grooves provided on the lower half circumference is equal to or greater than the sum of the cross-sectional areas on the inner circumferential side of the grooves provided on the upper half circumference.