JPS6116553B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION In electric resistance welding or electric arc welding using direct current or alternating current, the present invention covers and surrounds the molten part of the tip of the welding member in contact with the surface to be welded to shield the electric arc and prevent molten metal from scattering. The present invention relates to a protective tube for welding, which is used particularly on inclined or vertical surfaces to be welded.

This type of protection tube, which is generally called an arc shield or ferrule, is made of a heat-resistant electrically insulating material such as ceramics, and is used to protect the molten tip of welding parts such as welding rods and studs from the molten part of the welding member. and a groove-shaped gas vent hole. A suitable number of gas vent holes are provided at equal intervals in the circumferential direction at the tip edge of the annular hem to release the generated gas while preventing molten metal from scattering during welding. When welding a part to be welded at right angles, the molten metal flows almost evenly around the entire circumference and rises up, surrounding the welding part, but when the surface to be welded is sloped or vertical, the molten metal flows due to gravity and the flow of gas. There is a problem that the welding tends to flow downward, and this tendency is particularly severe when welding relatively large-diameter welded parts, making it impossible to achieve complete welding.

The present invention is intended to eliminate such drawbacks, and as shown in the embodiment of the drawings, a neck 2 having a through hole 1 having a diameter equal to or larger than the outer diameter of the welding member has a diameter larger than the through hole 1. An annular hem 4 having a cavity 3 is integrally formed, and an appropriate number of V-shaped gas vent holes 5 are provided at the tip edge of the annular hem 4, excluding approximately half of the circumference.
... is provided, and the stepped portion 6 between the insertion hole 1 and the space 3 is inclined to increase the height of the space 3 corresponding to the portion that will be downward during welding, that is, the portion that does not have the gas vent hole 5... It is lowered.

The flat end face 7 of the annular hem 4, which has no gas vent hole 5, is formed within an angle range of approximately 60° < θ < 130° with respect to the center of the protective cylinder, and the stepped portion 6 is formed within the angle range of approximately 60° < θ < 130° with respect to the center axis of the protective cylinder. It is inclined within an angle range of approximately 5° < α < 10° with respect to a perpendicular plane. Furthermore, in order to ensure accurate vertical positioning during welding, a linear indicator 8 is provided on the outer circumferential surface of the annular hem 4 to indicate the portion that will become the upper end surface of the protective cylinder.

The protection tube of this embodiment configured in this way is used when, for example, studs are welded onto the surface of a metal member 11 installed on a vertical plane in a building structure, a ship, etc., and is a portable welding tube. The flat tip surface 7 that covers and surrounds the stud protruding from the tip of the machine 12 and does not have the gas vent hole 5 is located at the bottom, that is, the side where the height of the cavity 3 is lower is located at the bottom. The studs are welded onto the vertical surface of the metal member 11 by welding using the usual electric resistance method or electric arc method, with the indicator 8 facing upward.

FIG. 4 is a side view of the state in which the studs 13 are welded, and the gas generated during welding passes through the gas vent holes 5 provided on the sides and upper part of the annular skirt 4. Since the lower half of the molten metal is almost blocked, the molten metal that is ejected from the stud 13 and tries to flow downward by gravity is pushed up by the gas flow that swirls and blows up. 3
Since the stud is narrow, only a small amount of molten metal accumulates below, and as a result, the weld metal 14 is formed by substantially evenly wrapping the entire circumference of the stud.

As described above, the present invention is an annular member that comes into contact with an inclined or vertical surface to be welded and covers and surrounds welding members such as welding rods and studs, in which gas vent holes are provided except for the substantially lower half of the annular member. Therefore, by placing the flat end surface without a gas vent hole in contact with the surface to be welded and positioning it downward during welding, the molten metal can be collected without leaking even if it flows down by gravity, and at the same time As the gas swirls and flows toward the upper gas vent hole, this gas flow pushes up a portion of the molten metal that accumulates below, and for this reason, the height of the cavity in the lower half is low. Therefore, the amount of molten metal that flows down and accumulates in the lower part is limited to a small amount, so that the weld metal is formed so as to cover the entire circumference of the welded member almost evenly. For this reason, when welding a relatively large diameter welded member with a diameter of approximately 10 mm or more,
Compared to small-diameter ones, the amount of molten metal generated is large and the welding time is long, so the tendency for the molten metal to flow down is particularly noticeable and only the lower half is welded. It is possible to perform complete welding in the same way as when

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing an embodiment of the present invention, Fig. 2 is a vertical sectional view showing an embodiment of the present invention;
The figure is a front view, the third figure is a plan view showing how to use it, and the fourth figure is a plan view showing how to use it.
The figure is a side view showing the welded state. 1...Insertion hole, 2...Neck, 3...Vacancy, 4...
...Annular hem, 5...Gas vent, 6...Step, 7
...Flat tip surface.

Claims (1)

[Claims] 1. A suitable number of gas vent holes are provided at the tip edge of the annular hem that covers and surrounds the fused portion of the tip of the welding member in contact with the surface to be welded, excluding the flat tip surface of approximately half of the circumferential direction,
Further, the welding protection tube is characterized in that the height of the hollow space inside the annular hem is lower on the side where the gas vent hole is not formed.