JPS6037296A - End tab for welding - Google Patents

Abstract

PURPOSE:To provide an end tab which has good bead formability and versatility and does not require time for preparation by consisting said tab of refractories provided with continuous or discontinuous projections on the surface covering the part near the end of a groove. CONSTITUTION:Members 1, 1' to be welded are butted to face each other and a groove 2 is formed by using a backing strip 9. End tabs 3 formed of refractories having projections on the covering surfaces having an adequate shape of sizes a-d are pressed to the ends of the groove 2 side. Bolts 8 of supporting jigs each consisting of, for example, magnets 4, 4', a nut 7 provided at the center of a leaf spring 5, a bolt 8 and a stopper 6 are tightened to press and support the tabs 3 toward the center of the groove 2 and thereafter the groove is welded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a welding end tab that is used by abutting against the end face of a welded member on a groove line when butt welding opposing welded members.

Conventional technology and its problems Conventionally, when welding grooves by butting grooves of parts to be welded, a groove is placed on the upper end surface of the groove line of the parts to be welded, regardless of the length of the part to be welded. As shown in Figure 1, an end plate or waste plate usually called an end tab is applied by dividing a piece of the same material as the part to be welded into small parts, welding is performed on the entire length including these end tabs, and the end tab is removed as a final finish. That's what I was doing.

However, with this method, it takes a considerable amount of time to attach and remove the end tabs.In other words, for long parts to be welded, there are not many end tabs, so it is necessary to prepare the end tabs.

The time required for installation, removal, finishing, etc. accounts for a relatively small proportion of the total welding work, but since the welding length is short for short workpieces, the welding time at that point is relatively short. In the case of large structures that use many short welded parts, there will be thousands of welding points, which means that there will be a large number of end tabs, and the time ratio for ancillary work such as preparation, installation, removal, and finishing will be large. , which has the disadvantage of being extremely inefficient. In addition, when welding high-strength steel, the marks of the end tab and tack bead portion harden, resulting in an arc strike-like defect, which also has the disadvantage of reducing welded joint performance, especially bending strength and fatigue strength.

By the way, Japanese Patent Publication No. 48-28545 aims to shorten welding work time by omitting the labor of preparing, attaching, removing and finishing end tabs, and improve welding performance by eliminating defects such as arc strikes. In this case, instead of the conventional end plates or waste plates that are the same as the parts to be welded, a refractory solid material mainly composed of silica, zirconia, alumina, and magnesia-based metal oxides is used, and the thermal conductivity at room temperature is 1. A welding end tab has been proposed in which a gap of an arbitrary shape is bored in accordance with the shape of the joint and the shape of the groove in a highly thermally conductive refractory solid material of 2-10.6 Km/m-hr-Tll. However, since such an end tab must be installed by accurately aligning the groove groove and the groove of the end tab during welding, it takes time to prepare for installation. Furthermore, if the bevel precision is poor, the gap between the bevel surface and the end tab becomes large, and molten metal may drip down. In addition, since the grooves of the end tabs must be matched to the joint shape and groove shape, there is a drawback that many types of end tabs with different groove shapes must be prepared and stored.

Purpose of the Invention In order to improve the drawbacks of the conventional end tabs made of a refractory solid material, the shape thereof was studied. As a result, by providing continuous or discontinuous protrusions on the surface that covers the vicinity of the groove end of the end tab, bead formation properties are good.
It is possible to provide a welding end tab that is versatile, does not require directionality of the end tab, can prevent molten metal from dripping, and can greatly reduce the number of types of end tabs.

Constituent Functions and Effects of the Invention The gist of the present invention is a welding end tab made of a refractory material having continuous or discontinuous protrusions protruding from the groove end and the surface surrounding the groove end. be.

The present invention will be explained in detail below.

As shown in FIGS. 2 and 3, the workpieces 1 and 1' are butted facing each other, and a groove 2 is formed using the backing metal 9f. The end tab 3 of the present invention is brought into contact with the side edge of the groove 2, and the magnets 1-4 and 4' are provided at the center of the leaf spring 5.
After tightening the support jig 8 to suppress and support the end tab toward the center of the groove 2, groove welding is performed.

Note that the tightening jig for the end comb 3 here uses a type that uses a plate spring to fix the end tab with a holding magnet, but it is not limited to this, and as long as it can fix the end comb, it can be used as shown in Figure 2. There is no problem in using other tightening jigs.

The fire-resistant isomorphic material constituting the welding end tab of the present invention is:
As shown in the examples in Figures 5 and 6, the groove end and the surface surrounding the groove end have continuous or discontinuous protrusions, so the groove shape and joint shape are different. Also, the same type of end tab can be used without having to change the end tab in particular. In addition, the protrusions that protrude before welding, for example 10 in Figure 5 (a), become molten slag at the part that contacts the bead during welding, forming a flat slag layer 11 in Figure 5 (c) and forming a bead. Because of this protection, a uniform bead with good conformability and no defects such as undercuts can be obtained.

With a flat end tab without protrusions as shown in FIG. 1, there is no need to change the end tab even if the groove shape and joint shape are different, but under force and tension are likely to occur at both ends of the bead. In addition, there may be less excess material, making it difficult to obtain a good bead. Concave groove 12 without protrusions shown in FIG. 1(C)
Although the bead appearance of end tabs with grooves provided with grooves is good, if the groove shape and joint shape change, as mentioned above, an end tab with a groove shape that matches the change must be used.

Furthermore, as shown in FIGS. 6(a) to 6(3), there are many possible shapes for the protrusion, but if the protrusion is symmetrical, it can be attached and welded regardless of the vertical, horizontal, or horizontal directions, and a good bead can be obtained.

For example, in the case of an asymmetrical shape (g) (male), a good bead can be obtained in either the downward or horizontal direction, but the bead in the other direction may be poor due to the groove shape and joint shape. Although the shape may be slightly deteriorated, it is fully practicable depending on the groove shape of the welded joint and is within the scope of the present invention.

Further, since the tab material of the present invention has a protrusion, the allowable range of the difference in protrusion of the open end is wider than that of an end tab with a groove, and dripping of molten metal can be effectively prevented.

Furthermore, since the end tab of the present invention can be used without being affected by the groove shape or joint shape, it is not necessary to prepare, store, and manage many types of end tabs with different groove shapes, unlike in the case of conventional grooved end tabs. It can eliminate the disadvantage of having to do it. The height of the protrusion may be adjusted as necessary to adjust the height of the extra bead formed on the bead surface, but it is usually preferably 05 to 4.

An example of one dimension of the end tab of the present invention is shown in Table 2 using FIG. 4.

Next, the effects of the present invention will be explained in more detail using embodiments and comparative embodiments in which the end tabs of the present invention are specifically welded.

Example of implementation This example is for 5iO251Wt, AA20332'wt
A test was conducted using a refractory having a composition of MgO17wtLlj.

Table 1 shows the test results for the end tabs of the embodiment of the present invention and the conventional end tabs. In the same table, genus 1 to Ifx 7
are examples of the end tabs of the present invention, and Knees 8 to Sake 9 are comparative examples that do not satisfy the structural conditions of the end tabs of the present invention.

Among the examples of the end tabs of the present invention, A1 to A5 have symmetrical protrusions, the bead shape at the open end is good, and installation is easy and versatile by simply touching the tab to the open end surface. This is an extremely excellent end tab that has no directionality, has a wide groove tolerance, and is easy to store. However, when the asymmetrical flats 6 to &7 are used with the protrusion vertically, there is almost no difference in advantages over the symmetrical type, but when the protrusion is used horizontally, the fit of both ends of the bead becomes slightly worse and the direction Although it is slightly inferior to the symmetrical example due to its characteristics, it is superior to the comparative example and is within the scope of the present invention.

If the shape of the end tab of the second table 8 is flat, undercuts will occur at both ends of the bead, making it impossible to obtain a uniform excess height. If the end tab of Flat 9 is grooved, a good bead shape can be obtained, but the bead shape and groove shape must be precisely matched, so there is no versatility, there is directionality, and the bevel tolerance is narrow. Since there are many types of joints with different groove shapes and joint shapes, it is necessary to secure a groove shape that matches them.

Therefore, many end tabs with different groove shapes are required, and it is difficult to prepare and store them.

As described above, using the end tab of the present invention not only improves welding performance and workability, but also eliminates the hassle of preparing, attaching, removing, and finishing the end tab, and significantly shortens welding work time. , the number of types of end tabs to be stored can be reduced.

[Brief explanation of the drawing]

Figures 1 (A), (B) and (C) are a plan view and a side view showing an embodiment of a conventional end tab; Figure 2 is a plan view of an embodiment using the end tab of the present invention; The figure is a side view of Figure 2, Figures 4 (A) and (B) are a plan view and side view showing one embodiment of the end tab of the present invention, and Figures 5 (A) and (B) are the end tab before welding. state, (c). 6) are plan and side views showing the state of the end tab after welding. )←). 2) and (6) are a plan view and a side view, respectively, showing embodiments of the end tab of the present invention. l, 1'... Part to be welded 2... Groove 3... End tab 4.4'... Magnet 5... Leaf spring 6
... Stop 7 ... S, T 8 ... Delt 9 ... Backing metal 10 ... Protrusion 11 ... Slag layer 12 ... Groove Fig. 1 (A) (C) No. Figure 2 Figure 3 Figure 4 Item - c - → Figure 5 (A) (C) Figure 6 (A) (C) (B) (D) (E) (G) 6th (S) (R) )

Claims (1)

[Claims] An end tab for further welding of a refractory material having continuous or discontinuous protrusions protruding from the groove end and the surface surrounding the groove end.