JPH0144231Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a stud welding jig used for welding a stud to the tip of a protruding bar-shaped base material such as a stud.

For example, as a method for repairing studs in boiler tubes, from the viewpoint of workability, attention has been paid to a technique in which repair studs are directly welded onto the tips of worn studs using arc stud welding. As is well known, the arc stud welding method is a method in which welding current is passed between the base metal and the stud to be welded to generate an arc between the two parts, and the stud is pressed against the base metal to perform welding. Various arc shields are actually used for good welding and overfill formation.

However, most conventional arc shields are designed with the assumption that the weld site is a substantially flat or slightly curved surface. Therefore, when stud-welding is performed on the tip of a protruding bar-shaped base material like a stud, existing arc shields cannot be used, and a specially designed one must be used. However, preparing such a special arc shield usually increases the cost of the arc shield because it needs to be matched to the size or shape of the protruding rod-shaped base material, and as a result, the welding operation cost is also high. Become.

Therefore, the purpose of this invention is to provide a stud welding jig that allows stud welding to the tip of a protruding bar-shaped base material using an existing arc shield if it matches the diameter of the stud to be welded. There is a particular thing.

That is, the stud welding jig according to this invention has a central hole dimensioned so that it passes through a protruding rod-shaped base material and locks at a substantially fixed position from the tip, and the stud welding jig has a central hole that is dimensioned so that it is inserted through a protruding bar-shaped base material and is locked at a substantially fixed position from the tip. It is characterized in that it has a receiving surface for receiving the tip of the arc shield, and this receiving surface is provided with a flange for positioning and holding the arc stud.

An embodiment of this invention will be described below with reference to the drawings.

Figures 1 and 2 show a stud welding jig according to this invention, which is preferably composed of a circular plate made of ceramic or heat-resistant plastic, with a stud S shown in Figure 3 in the center of the jig. A central hole 1 is provided through which a protruding rod-shaped base material such as
This central hole 1 is sized according to the diameter of the rod-shaped base material. Furthermore, eight flanges 2 are provided on the peripheral edge of the disk at approximately equal intervals over the entire circumference. These flanges 2 serve to guide an arc shield (not shown) and to position and hold the studs in the arc shield relative to the rod-shaped base material. Furthermore, an annular arc shield receiving surface 3 is provided between the center hole 1 and the peripheral flange 2.
is defined. Naturally, the size of the arc shield receiving surface 3 should be determined depending on the outer diameter of the arc shield used. Further, the dimensions of the central hole 1 are determined so that the distance from the arc shield receiving surface 3 to the tip of the rod-shaped base material is approximately constant. The arc shield receiving surface 3 receives the arc shield and defines a welding space together with the arc shield, and also functions to prevent molten metal from dripping during welding and to form a necessary surplus. Also, each flange 2
The interspace 4 cooperates with the vent holes of the arc shield used to advantageously effect venting. This arc welding jig can be used repeatedly depending on its constituent materials.

In this way, by using the stud welding jig according to this invention, it is possible to use an existing arc shield to weld a protruding rod-like matrix, such as stacking studs on top of studs, without the need to prepare a special arc shield. When performing stud welding on the tip of a material, good welding with desired welding strength can be easily and efficiently performed by guiding and positioning the stud. Further, in the illustrated embodiment, the flange 2 is provided at the peripheral edge of the receiving surface 3 to guide the arc shield from the outside, but it is natural that the flange 2 is provided around the central hole 1 to guide the arc shield from the inside. Good too. Furthermore, flanges 2 are provided on both the upper and lower surfaces of the disk, and the central hole 1 is formed in a conical shape, so that the flanges 2 can be attached to either the upper or lower surface depending on the condition of the base material to be welded (for example, the degree of wear in the case of boiler tube studs). By using this as the receiving surface of the arc shield, the distance from the receiving surface to the tip of the base metal can be kept almost constant.

[Brief explanation of the drawing]

Figure 1 is a plan view of the stud welding jig according to this invention, Figure 2 is a sectional view taken from the direction of arrow A-A in Figure 1, and Figure 3 is a welding method in which studs are stacked on top of each other. It is a figure which shows the example of use of the jig by this invention in case. In the figure, 1: center hole, 2: flange, 3: receiving surface, 4: gas vent gap.

Claims (1)

[Scope of utility model registration request] In a stud welding jig used to weld a stud to the tip of a protruding bar-shaped base material such as a stud, it is passed through the protruding bar-shaped base material and is locked at a substantially fixed position from the tip. It is characterized by having a sized central hole, a receiving surface for receiving the tip of the arc shield around the entire circumference of the central hole, and a flange for positioning and holding the arc stud on this receiving surface. Jig for stud welding.