JPH04138879A - Butt welding method for welding flux-cored wire electrode - Google Patents

Abstract

PURPOSE:To improve strength of a joined part and to prevent the generation of inconvenience such as buckling, curvature and the deflected diameter of wires by crushing the sheaths of two wire ends to be joined to form edge parts, intersecting the edge parts to perform butt welding. CONSTITUTION:When the wire 1a or 1b is rotated by 90 deg. with the wire axial direction as a center, the edge parts of the wires 1a and 1b are superposed on each other. Since the sheaths are crushed and the edge parts 2a and 2b are formed by cutting the edges of the wires 1a and 1b by cutting pliers prior to butt welding in this way, flux 3 is shut in the inside of sheath steel pipes and the flux is thus prevented from being made into slag by resistance heat by energizing and a weld zone 6 in a good fushed state is obtained. In addition, since the sheaths are crushed and the formed edge parts are intersected each other and preferably intersected crosswise and abutted on each other, a butt part is not deviated and a thickness deviation is not caused and the satisfactory joined part 6 is obtained.

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 divided into pairs 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 contacting at t@, remove burrs and perform annealing.

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

However, for welding flux-cored wire, 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 deposited metal, the same procedure as for welding solid wire is used. When butt welding is performed, the heat of butt welding melts the filled flux and turns it 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 further limiting the length of the welding allowance, which directly affects the degree of fringing, to a predetermined length or less (especially Kosho 64-6877>.

[Problem to be solved by the invention]

Adjusting this welding allowance is time-consuming and cannot be done easily, so it is extremely difficult to form a good welded joint while keeping the firmness to a level that does not cause any inconvenience in the wire drawing process after hat welding. . 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, it is possible to connect not only regular welding flux-cored wires with seams, but also seamed wires whose shell metal is welded joint pipes, seamless wires without seams, and the welding results are excellent. 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 for Solving the Problems) 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 The method involves crushing the outer skin of the end of the wire to form a ridge, and butt welding the ridge across.

[Effect]

In the present invention, the ridge portion is formed by crushing the outer metal tubes at the ends of the two wires to be connected. For example, by cutting the wire ends on a bench, the outer skin can be crushed and the ridges formed at the same time.

As a result, the end of the wire becomes a solid wire and is closed, and the flux within the sheathed metal tube is trapped. Therefore, the flux is not heated and turned into slag due to resistance heat during butt welding, and a welded joint with a good fusion state can be obtained. In addition, since the outer skin is formed by crushing and abutted against each other with the ridges intersecting, preferably crisscrossing, a good welded joint can be obtained without displacement of the abutted portion and without uneven thickness. Furthermore, since the wire end is a solid wire with no flux, there is no inner surface plash that occurs on the inner and outer surfaces of the tube during butt welding, and only the outer surface pall that is easy to remove, which eliminates the conventional problem. 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 metal pipe 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 crushed ends of two wires 1a and 1b used for butt welding. The ridges are shown facing each other so that they form a cross. When the wire 1a or 1b is rotated 90' around the wire axis direction, the ridges of the wires la and lb overlap. In this way, wire la is prepared prior to butt welding.

Since the outer skin is crushed by cutting the end of 1b on a bench to form the ridges 2a and 2b, the flux 3 is trapped inside the outer skin steel pipe, and as a result, the flux slags due to the resistive heat caused by energization. It will not change.

Figure 2 shows the wires la and lb in the state shown in Figure 1, with one wire la held by the fixed electrode 4a and the other wire ib held by the movable electrode 4b, and the ridges 2a and 2b of the wire ends crisscrossed. This shows the state in which they are compared. and electrode 4a,
A large alternating current is passed through the wires 4b to heat the welding area by resistance heat generation, and when a suitable high temperature is reached, strong pressure is applied in the axial direction of the wires to join them.

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.

[Effects of the Invention] In the present invention, since the welded joint is a solid wire with good ductility made of the same material as the wire sheath metal, the flux-cored wire for welding is joined and then the wire is drawn. In this case, the joint portion is elongated as the diameter of the wire is reduced, and the wire can be drawn very 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 congint tube, feeding rollers, etc., and therefore good welding can be performed.

In addition, since the ridges formed by crushing the outer skin are butted against each other in a crisscross manner, preferably in a criss-cross manner, a good welded joint can be obtained without shifting the butt portions and without uneven thickness.

[Brief explanation of the drawing]

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

Claims (1)

[Claims] 1. A butt welding method for welding flux-cored wire made by filling a sheathed metal tube with flux, in which the sheaths at the ends of two wires to be connected are crushed to form a ridge, and the ridge is A method of butt welding flux-cored wire for welding, which is characterized by cross-butt welding.