JPS5921272B2 - Spark butt welding method - Google Patents

Description

[Detailed Description of the Invention] This invention first abuts the materials to be welded together, and then momentarily pulls them apart slightly at the right time by applying an electric current, and a flash (spark) occurs on the abutting surfaces. The metal in contact will melt.

The present invention relates to a so-called spark butt welding method (flash butt welding method) in which the joint end surfaces are purified and the two are upset and pressure-welded without the presence of impurities. 1st
The figure shows a state in which a pair of materials to be welded 1 and 2 with relatively good butt end shapes before welding are held by a copper fixed clamp 3 and a movable clamp 4. In this case, both materials to be welded are Since the butt ends of materials 1 and 2 require dimensional flash allowances F, F and upset allowances U, U, respectively, in order to weld them with material 1.2 to be welded by spark butt welding. This will result in at least 2F+2U of wasted material.

However, in the actual welding process, the end surfaces of the welded materials 1 and 2 that have been cut by a cutting machine or extruded are not in a good condition as shown in FIG. 1, but are as shown in FIG. As shown in the figure, most of the shapes are extremely irregular and disordered.

Therefore, in such a case, in addition to the flash allowances F, F and upset allowances U, U necessary for welding, the end face must be made into a good surface by a flash operation before the regular flash process. You will need to pay for plastic surgery to fix it.
Therefore, not only does the welding time become longer, but there is also a large amount of waste in the materials to be welded, and there are also disadvantages in that there are many "variations" in terms of quality in the welding condition of the welded portion.

In addition, if the above-mentioned shaping allowance is large, the regular flash allowance F, F will be less than the set value, and in extreme cases, the upsetting process is often started without the end face being sufficiently purified during welding, and the welding is often performed. Defects may occur.
In order to cope with this, the flash allowances F and F may be increased in advance, but this not only increases the welding time but also has the drawback of increasing waste of the material to be welded. This invention has been made with attention to this point, and the end face shape of the materials 1 and 2 to be welded is plastically modified to a flat shape before the flashing process to reduce the shaping allowance t, thereby reducing the welding time. The purpose of the present invention is to provide a spark butt welding method that reduces the time required, saves materials, and improves the quality of the welds and welds.

That is, FIG. 3, 1,... shows an embodiment of the process according to the welding method of the present invention, in which the stroke of one of the materials to be welded 2 by the movable clamp 4,
It shows the relationship between voltage, hexagram, and current.

That is, in FIG. 3 1, from the state shown in FIG. 2 in which the materials to be welded 1 and 2 with irregular end face shapes are butted together, one of the materials to be welded 2 is applied to a predetermined pressure P via the movable clamp 4. This shows a process of plastically correcting the irregularly shaped end surfaces of the materials to be welded 1 and 2 into flat shapes by moving them by a predetermined stroke.

FIG. 4 shows this state in an enlarged manner. Fig. 3 shows a state where a predetermined voltage is applied to start welding, and Fig. 3 shows a flattening process in which a predetermined current flows between the two materials to be welded 1 and 2, causing flashing on the abutting surfaces. Furthermore, the third
The figures each show an absorption process in which the flashing step due to the flashing margin is completed, the applied voltage is briefly cut off, the bonding end faces are cleaned, and the bonding surfaces are pressed together without any impurities present. In addition, FIG. 5 shows the above-mentioned plastic process (FIG. 1
), between the butt end faces of both materials to be welded 1 and 2,
A flat plate-shaped correction piece 5 is inserted, and by using this correction piece 5, the butt end faces of the two materials to be welded 1 and 2 are further flattened and plastically corrected. Needless to say. In this case, the materials to be welded 1 and 2 may be moved simultaneously or alternately relative to the correction piece 5. Further, it goes without saying that the pressurizing force P of the movable clamp 4 holding one of the materials to be welded 2 may be applied not only to the line mechanism of the welding machine but also to other attached devices. According to the spark butt welding method of the present invention, as described above, before starting welding by applying a predetermined voltage, the materials to be welded are abutted against each other under a predetermined pressure, and the irregularly shaped end faces are plastically corrected into a flat shape. I decided to do this, so
Compared to conventional methods, the plastic surgery cost t is extremely small,
This method has excellent effects such as shortening welding time, saving materials, and improving the quality of welds and welds.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the material to be welded with a relatively good shape of the butt end face, Figure 2 is an explanatory diagram of the material to be welded with an irregular shape of the butt end face, and Figure 3 is an explanatory diagram of the material to be welded with a relatively good shape of the butt end face. A process diagram of the spark butt welding method of the invention, FIG. 4 is an enlarged view during the end face plasticity correction process, and FIG. 5 is an explanatory view when a correction piece is used during the plasticity correction process. In the drawings, 1 and 2 are materials to be welded, 3 is a fixed clamp, and 4 is a movable clamp.

Claims (1)

[Claims] 1 A process of holding a pair of welding materials between a fixed clamp and a movable clamp by butting their end surfaces, and applying a predetermined pressure to the butted end surfaces before starting welding by applying a predetermined voltage to both of the welding materials. A spark butt welding method that involves the process of plastically modifying regularly shaped end faces into flat shapes.