JPS6353917B2 - - Google Patents

Description

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

Generally, in the wire drawing industry, when continuous work is performed by connecting wire rods together, butt welding involves applying electricity to heat the area around the contact area to the welding temperature using contact resistance and heat generation based on the specific resistance of the material, and pressurizing and crimping. Butt resistance welding methods such as flash welding and flash welding methods are used. Flat welding is used for cases with large cross-sectional areas that are difficult to butt weld, or for thin-walled plates and pipes, and for welding wires with small cross-sectional areas, the equipment is simple and inexpensive, and the work can be performed easily and safely. Butt welding is used, and butt welding machines of various capacities are used depending on the wire diameter. The procedure for butt welding welding wire is as follows: (1) Polish the surface of the wire and the end face of the material to be welded, align the end faces, and butt them together firmly.

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

(3) Apply upset pressure using a spring, etc.

(4) After welding, remove burrs and perform annealing.

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

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

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 appearance of burrs, to a predetermined length or less. Adjusting this welding allowance is time-consuming and cannot be done easily, so it is extremely difficult to suppress burrs to a level that does not cause any inconvenience in the wire drawing process after butt welding, and to form a good welded joint. . 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 is likely to occur and may lead to wire breakage, and in product wires,
During wire feeding during welding, buckling, bending, and deviation in diameter of the wire are likely to occur, 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 ordinary flux-cored wires for welding with seams, but also flux-cored wires for welding, such as seamed wires in which the outer steel pipe is a welded joint pipe, and seamless wires without seams, and the welding result is 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. The gist of the present invention to achieve this object is a method for butt welding a flux-cored wire for welding, which is made by filling a jacketed steel pipe with flux, and which removes flux from the ends of two wires to be connected. , after embedding a deoxidizing agent in the wire ends, the wire ends are brought together and butt welded.

In the present invention, since the flux at the end of the flux-cored wire for welding is removed using, for example, a drill, the flux does not turn into slag due to the heat during butt welding, and therefore a well-fused welded joint can be achieved. part is obtained.

Furthermore, since a deoxidizing agent is embedded in the void at the end of the wire after the flux has been removed, the deoxidizing agent is fused with the steel pipe at the same time during butt welding, effectively removing oxygen that degrades ductility in the weld metal. Effective deoxidizing elements are contained in the steel, which can improve mechanical properties. Therefore, the raised parts on the inner surface of the weld metal (corresponding to conventional burrs), which have been a problem in the past, have good ductility, so there is no problem such as wire breakage during wire drawing due to the raised parts. Furthermore, since no voids are formed in the welded joint, the strength of the welded joint is not inferior to that of other parts of the wire, resulting in good wire drawing conditions during manufacturing and good wire feeding in the finished product. bring sex. Note that the outer surface protrusions of the weld metal can be easily removed with a grinder. In the present invention, the commonly used deoxidizing agents to be embedded in the wire ends include ferrosilicon (Fe-Si), ferromanganese (F-Mn), ferrotitanium (Fe-Ti), and silicon manganese (Si-Mn). ) etc., but preferably the same deoxidizing agent as that in the packed flux is used. When drawing the wire after butt welding, the grain size of the deoxidizing agent to be embedded should be set to 1/1/2 of the cross-sectional inner diameter of the final wire diameter, taking into consideration wire drawability.
It is preferable to set it to 3 or less.

The butt welding method of the present invention will be explained below with reference 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 two wires 1 and 1' filled with fluxes 2 and 2 used for butt welding. A state is shown in which the flux at the end is removed to form a void, and the deoxidizing agent 3 is embedded in the void. Since the flux at the ends of the wires 1 and 1' is removed prior to welding in this way, there is no problem caused by the flux turning into slag due to resistance heat of the wires due to energization. Figure 2 shows that one wire 1 of the wires 1 and 1' in the state shown in Figure 1 is connected to the fixed electrode 5, and the other wire 1'
is held by the moving electrode 5', and the wire end faces are aligned and butted against each other. and electrodes 5, 5'
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. Third
The figure shows this joining state.As a result of pressure joining, weld metal protrusions 4, 4' are formed on the inner and outer surfaces of the tube at the joint, and the protrusions 4 on the inner surface of the tube fuse together to form the joint. It becomes a bar state at . FIG. 4 is a diagram showing a state in which the raised portion 4' on the outer surface of the tube has been removed by a grinder, and from this, the wire 1,
1' butt welding is completed. The amount of deoxidizing agent to be embedded in the wire end should be determined from the wire end to the welding distance.
Simply remove the flux by 1.3 to 1.5 times the length to create a gap, and embed the deoxidizer with the deoxidizer embedding length approximately equal to the length of the welding allowance. Some voids remain. This welding allowance is the length of the wire consumed by butt welding, that is, half the moving length of the moving electrode 5', and is approximately equal to the diameter of the wire to be welded. For example, change the wire diameter to 5
mm, the flux extraction length, that is, the gap length, is 8 mm, and the deoxidizer is added 5 mm from the deep side of the gap.
Embed. At this time, the deoxidizing agent is Si with a particle size of 0.25 mm or less.
- As a result of embedding 0.2 g of Mn powder (Si: 20%, Mn: 60%, Fe: 20%) into each wire end and butt welding, the composition of the wire jacket tube (Si0.1%,
The composition of the weld metal is Si: 0.1 to Mn=0.2%.
By increasing the amounts of Si and Mn to 0.3% and Mn: 0.5 to 1.0%, the welded joint became an alloy bar containing deoxidizing elements. It is difficult to obtain the desired effect even if the embedded length of the deoxidizing agent is too short or too long, and a length corresponding to the wire diameter is most preferable. If it is too short, the deoxidizing agent will not be sufficiently fused to the weld metal, the mechanical properties cannot be improved, and the yield of the deoxidizing element will be low. On the other hand, if it is long, a large amount of deoxidizing elements will remain in the weld metal, causing work hardening during wire drawing after butt welding, and the wire is likely to break at the joint due to lack of ductility.

When the flux-cored wires 1 and 1' for welding are joined in this way and then subjected to wire drawing processing, there are no hard burrs inside the wires, and instead, ridges of weld metal with good ductility are formed. Therefore, as the diameter of the wire is reduced, the joint is stretched, and the wire is drawn very well without any problems such as wire breakage. Furthermore, when the product wires are joined, the wires are subsequently subjected to automatic or semi-automatic welding, but in order to prevent the flux from turning into slag, the present invention not only removes the flux and forms voids, but also removes the flux. By embedding an acid agent and forming a raised part of the weld metal at the joint to form a solid wire, the strength of the joint is superior to that of simply providing a gap, and the conduit tube is not necessary when feeding the wire during welding. The wire is fed extremely smoothly without any problems such as buckling, bending, or uneven diameter of the wire due to internal resistance or feeding rollers, and the welding performance of the joint is almost the same as that of other wire parts. Therefore, good welding can be performed.

[Brief explanation of the drawing]

1 to 4 are explanatory diagrams showing the butt welding procedure of the present invention. In the drawing, 1 and 1' are wires, 2 is flux, and 3
is a deoxidizing agent, 4 and 4' are raised parts, and 5 and 5' are electrodes.

Claims (1)

[Claims] 1. A method of butt welding a flux-cored wire for welding, which is made by filling a sheathed steel pipe with flux, in which the flux is removed from the ends of two wires to be connected, and a deoxidizing agent is embedded in the ends of the wires. A method for butt welding a flux-cored wire for welding, characterized by butt welding the rear wire ends together.