JPH04138878A - Butt welding method for welding flux-cored wire electrode - Google Patents

Abstract

PURPOSE:To abut wire ends on each other after shutting flux in sheath metallic pipes and to perform butt welding by crushing the sheaths of two wire ends to be joined to close up the wire ends. CONSTITUTION:The sheath metallic pipes of the two wire 1a and 1b ends to be joined are crushed to close up the wire ends. When the wire ends are cut by cutting pliers, for instance, since crushing and cutting of the sheaths can be carried out at the same time, it is convenient. The wire ends are made in a solid wire shape and closed up and flux 3 in the sheath metallic pipes is shutted up by crushing the sheaths of the wire ends in this way. Accordingly, it is prevented that the flux 3 is heated and made into slag by resistance heat at the time of butt welding and a welded and joined part 6 in a good fused state is obtained. In addition, since the welded and joined part 6 is made in a solid wire shape to generate good elongation in the same way as a sheath part, when the wire is drawn after butt welding, satisfactory drawability is obtained without generating disconnection.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a butt welding method for welding flux-cored wire used in automatic or semi-automatic welding.

[Conventional technology]

Generally, in the wire drawing industry, when continuous work is performed by connecting wire rods, the area around the contact area is raised to the welding temperature by using heat generated by contact resistance and the specific resistance of the material by applying electricity.
Butt resistance welding, such as butt welding or flash welding, in which pressure is applied and crimping is used, is used. Flash welding is used for large cross-sectional areas that are difficult to butt weld, as well as thin-walled plates and pipes.Flash welding is used for welding wires that have small cross-sectional areas, and the equipment is simple and inexpensive, and the work can be performed easily and safely. Butt welding is used, and butt welders of various capacities are used depending on the wire diameter. The procedure for butt welding welding wires is as follows: (1) Polish the end faces of the materials to be welded, align the end faces, and strongly butt them together.

(2) Apply electricity to heat the area around the welded area by resistance heat generation.

(3) Applies upset pressure using a spring or the like.

(4) After welding, remove the flash and perform annealing.

With this procedure, solid wire for welding can be welded without any problems.

However, with flux-cored wire for welding, which is made by filling a sheathed steel pipe with a flux that provides various necessary properties such as welding workability and toughness of the weld metal, welding is performed using the same procedure as solid welding wire. When welding is performed, the heat of butt welding melts the filled flux into slag, which remains on the interface of the welded materials, resulting in insufficient fusion and causing trouble. Further, after welding, unremovable burrs occur on the inner surface of the tube, and when wire drawing is performed after butt welding, these burrs often result in wire breakage. This is because the tube inside the tube is hard and is not drawn during the wire drawing process, so the wall thickness of the tube sandwiched between the die and the tube becomes thinner locally.

In order to solve this problem, there is a method of removing the flux at the ends of the two wires to be connected, and also trying to keep the length of the welding allowance, which directly affects the degree of fringing, to a predetermined length or less (especially Kosho 64-6877).

[Problems to be Solved by the Invention] Adjusting the welding allowance is time-consuming and cannot be done easily, so it is necessary to keep the welding distance to a level that does not cause any inconvenience in the wire drawing process after butt welding, and to form a good welded joint. is extremely difficult to form. Furthermore, with this method, voids are created in the welded joint of the wire, which tends to result in poor strength.As a result, when drawing the wire, especially during reverse tension wire drawing, the wire joint stretches and collapses, resulting in different diameters. This tends to occur, which may lead to wire breakage, and in product wires, buckling, bending, and uneven diameter of the wire are likely to occur during wire feeding during welding, which may result in poor feeding.

The present invention solves the above-mentioned conventional problems. In other words, welding flux-cored wires such as regular welding flux-cored wires with seams, seamed wires where the outer metal tube is a welded joint tube, and seamless wires without seams can be connected well, and welding results can be improved. The object of the present invention is to provide a butt welding method that has a positive effect on subsequent processes or usage conditions.

[Means to solve the problem]

The gist of the present invention to achieve this object is a butt welding method for a flux-cored wire for welding in which a sheathed metal tube is filled with flux, and the sheaths at the ends of two wires to be connected are crushed. The wire ends are closed to confine the flux in the outer metal tube, and then the wire ends are brought together and butt welded.

[Effect]

In the present invention, the outer metal tubes at the ends of two wires to be connected are crushed to close the wire ends. This is done by crushing the wire ends with a suitable tool. For example, it is convenient to cut the end of the wire with pliers because it allows the outer skin to be crushed and cut at the same time. By crushing the outer sheath of the wire end in this manner, the wire end becomes a solid wire and is closed, and the flux within the outer sheath metal tube is trapped. Therefore, the flux is not heated and turned into slag due to the resistance heat during butt welding, and a welded joint with a good fusion state can be obtained. Furthermore, since the wire ends are in the form of solid wires with no flux, there is no inner surface plash that is generated on the inner and outer surfaces of the tube during butt welding, and only the outer surface patter, which is easy to remove, which has been a problem in the past. The harmful effects of inner Paris will disappear. Since the welded joint is in the form of a solid wire that exhibits good elongation like the outer skin portion, when the wire is drawn after butt welding, it exhibits good wire drawability without causing wire breakage. Moreover, since no complicated work is required during butt welding, the work can be carried out efficiently.

〔Example〕

The butt welding method of the present invention will be explained below according to specific examples shown in the drawings. Figures 1 to 4 are diagrams sequentially showing the process from the start to the end of butt welding, and Figure 1 shows the process of cutting the ends of two wires la and lb to be used for butt welding on a bench. This shows a state in which the crushed portions 2a and 2b formed by the above are opposed to each other. In this way, the wire ends are crushed and only the part of the flux-cored wire used for butt welding is made into a solid wire, so the flux 3 is trapped inside the outer steel tube, and as a result, the flux 3 is absorbed by the resistance heat generated by energization. will not become slag.

Figure 2 shows a state in which wires la and lb are held in the state shown in Figure 1, with one wire la held by the fixed electrode 4a and the other wire 1b held by the movable electrode 4b, and the crushed portions 2a and 2b of the wire ends butted. It shows. Note that when the end portion of the wire is cut with pliers, the cut portion becomes a cutting edge shape, so it is preferable that the cutting edge portions are intersected and abutted. and electrodes 4a, 4b
A large alternating current is passed through the wire to heat the area near the welding area by resistance heat generation, and when the temperature reaches an appropriate high temperature, strong pressure is applied in the axial direction of the wire to join.

FIG. 3 shows this joining state. As a result of pressure joining, a weld metal protrusion 5 (burr) is formed on the outer surface of the steel pipe at the joint 6, and the wire end is a solid wire on the inner surface of the steel pipe. Due to the shape, substantially no protuberances are generated.

FIG. 4 is a diagram showing the state in which the raised portion 5 on the outer surface of the steel pipe has been removed by a grinder, and from this the wires la, lb
Finish the butt welding.

〔Effect of the invention〕

In the present invention, since the welded joint is a solid wire with good ductility and made of the same material as the wire sheath metal, when welding flux-cored wire is joined and then wire drawing is performed, the wire The joint portion is stretched as the diameter is reduced, and the wire can be drawn extremely well without any problems such as wire breakage.

In addition, when product wires are joined, the wires are subsequently subjected to automatic or semi-automatic welding, but in the present invention, the strength of the joint is superior to that of the conventional case in which a gap is provided at the joint, and the wire is used during welding. During feeding, the wire is fed smoothly without any problems such as buckling, bending, or uneven diameter of the wire due to resistance within the coduit tube, feeding rollers, etc., and therefore good welding can be performed.

[Brief explanation of the drawing]

FIGS. 1 to 4 are explanatory diagrams showing the butt welding procedure of the present invention. In the drawings, 1a and 1b are wires, 2a and 2b are crushed parts, 3 is flux, and 6 is a joint part. Applicant Nippon Steel Welding Industry Co., Ltd.

Claims (1)

[Claims] 1. A method of butt welding a flux-cored wire for welding in which a sheathed metal tube is filled with flux, in which the flux is removed by crushing the sheaths of the ends of the two wires to be connected and closing the ends of the wires. A method of butt welding a flux-cored wire for welding, which is characterized in that the ends of the wire are butt welded after being confined in a metal tube.