JPS5881594A - Production of flux cored wire for welding - Google Patents

Abstract

PURPOSE:To permit production of flux cored wire for welding free from the deterioration in the quality of the flux and the deterioration in the material quality in electric welded parts by using the flux in the form of pellets in producing said wire by the use of an electric welded pipe. CONSTITUTION:While a steel band 1 is transferred, the band is curved in a direction at a right angle to the longitudinal direction of the band with forming rolls 4, whereby the steel band is formed from a channel shape into a cylindrical shape. Both ide edges of the steel band are placed to face each other and are subjected to pulse TIG high frequency welding. The pipe is formed to an electric welded pipe 2 by squeezing rolls 5 and is passed through a coller 6, whereby the pipe is cooled. The flux 7 formed into a pellet glides into the pipe 2 at the speed faster than that of the band 1 and stops by striking against the preceding pellet 7. A space exists between the welding point 9 of the pipe 2 and the pellet 7 and since the pellet 7 passes through the welding point at a fast speed, the deterioration in the quality thereof by receiving the heat of welding is obviated. Since weld zones 10 do not contact with the pellets, the detects in the welded and joined parts owing to sticking of the flux are obviated.

Description

[Detailed description of the invention] Flux-cored wire for dynamic welding (seam wire)
The present invention relates to a manufacturing method.

Currently, flux-cored wires for welding are made by forming a copper strip into a certain cross-sectional shape and filling it with granular flux consisting of a deoxidizing element, a slag-forming agent, and the like. This welding wire is used in a wide range of applications, from mild steel to low-alloy and high-alloy steel welding.

The conventional method for manufacturing flux-cored wire is to form a thin steel plate into a U-shape, fill it uniformly with powder-like welding flux whose composition has been adjusted in a specified manner, form it into a specified cross-sectional shape, and then stretch it. It is used for wire processing.

1-noyers produced in this way have various drawbacks. In other words, when manufacturing a flux-cored wire or as a final product, the mating opening tends to open, which hinders wire manufacturing, and the following undesirable problems occur when welding using this wire. It was happening.

(1) If moisture on the outer surface of the wire or organic substances such as lubricants used during the manufacturing process enter the flux through the opening and weld using this, diffusible hydrogen in the weld metal will increase. This also promotes oxidation of the surface of the metal strip on the inner surface of the wire, increasing oxygen in the weld metal and deteriorating the mechanical performance of the weld metal.

(2) Flux leaks out of the wire from the opening, causing wear on the feed roller, which is part of the wire feed device of the welding machine.

(3) Although the ideal cross-sectional shape of the wire is originally a perfect circle, the cross-sectional shape is deformed by the opening, which adversely affects wire feeding performance.

In addition, in the case of solid wire for welding, copper plating is applied to the surface of the wire for the purpose of preventing rust on the wire surface and improving conductivity during welding. cannot be applied. The reason for this is that the copper plating process is a mixed method in which the object to be plated (wire) is immersed in a plating bath and plating is applied, which causes the inconvenience that the plating solution infiltrates into the wire through the seams. As a method to overcome this drawback, it has been proposed to weld and join the joints of the cladding tubes in parallel with the filling of flux. Example 1: Japanese Patent Application Publication No. 54-109040
According to the publication, a copper strip is formed into an open groove, and after flux powder is dropped and supplied into the groove to an extent that is not enough to enter the pipe during the next pipe making welding, the edges of the groove are closed together and the longitudinal A method of manufacturing a sealed tube by welding directional connections is shown by continuously forming the tube and reducing the size of the tube to tightly pack the flux powder inside the tube. In this method, the flux is configured so that it occupies only a part of the pipe rather than the entire pipe during welding, because if the welding position and flux position are too close, they will have a negative effect on each other. This is to prevent excessive heat from reaching the flux. That is, when welding the edge of a groove in a copper strip, there is a risk that the heat generated by welding will change the composition of the flux or make it unsuitable, and that the flux may become swirled by the magnetic field that is present due to welding. The reason is that it may adhere to the contact surface of the groove edge and weaken the weld, but this problem is not recognized to have been sufficiently solved by the above manufacturing method, and the weld and fluff or each other They were forced to influence each other negatively. According to the above manufacturing method, since the amount of flux supplied is limited, the flux filling rate of the product is inevitably limited to a low level, which is also a disadvantage. Furthermore, in the pipe size reduction process after welding, the entire pipe is filled with flux, the air inside the pipe is removed, and the flux is tightly packed to prevent the flux from moving in the pipe longitudinal direction.
There is a problem that = is likely to occur.

The present invention solves all the problems of the conventional art as described above.
In other words, one of the objects is to provide a method for manufacturing a flux-cored wire for welding, which does not open the joints of the wires during manufacturing or in the product, and which can be subjected to plating treatment such as copper plating. We provide a manufacturing method that allows pipes to be manufactured without adversely affecting each other and flux deterioration during welding of pipes, and that allows for a wide range of filling ratio designs and high production efficiency. An important purpose is to

The gist of the present invention to achieve this object is to form a copper strip into a cylindrical shape, weld both side edges of the copper strip to form an ERW tube, and supply and fill flux into the ERW tube. A method for manufacturing a flux-cored wire for welding by drawing a flux-cored electric resistance welded tube to a desired diameter includes forming flux into pellets and supplying the pelletized flux into the electric resistance welding tube to fill it.

In the present invention, pelleted flux is produced by dry-mixing flag material mixed in a predetermined ratio and then adding a binder (
For example, it refers to a pellet-like flux obtained by adding water glass), wet-mixing for an appropriate time using a fret mill, etc., extruding it from a nozzle opening with a press, shaping it, and drying it. The shape of the pelleted flux (hereinafter referred to as pellets) is preferably cylindrical to match the cross-sectional shape of the pipe, and the diameter of the cylinder is within the range of 0.5 to 0.9 times the inner diameter of the pipe. It is determined based on the desired filling rate. Further, the length of the cylinder is suitably within a range of 2 to 5 times its diameter, considering the strength of the pellet itself and the relationship with the insertion device. The strength of the pellets needs to be at least strong enough not to collapse during the process of feeding the pellets into the electric resistance welded tube, and weak enough to not easily collapse during the subsequent wire drawing process. The strength of such pellets is adjusted by the proportion of binder and degree of dryness.

The contents of the present invention will be explained in detail below. FIG. 1 is a flowchart showing a specific example of the manufacturing process related to the present invention.

In the copper strip supply (a), the copper strip wound around a bobbin or the like is drawn out and sent to the formation (b). In this forming process, the steel strip is bent from a groove shape to a cylindrical shape by a forming roll, and then sent to the next pipe making step (c), where it is welded by, for example, pulsed TIG high frequency welding while being pressurized by a squeeze roll. Formed in the suture tube.

The supply and filling of flux is carried out in parallel with this tube making (c), and this state will be explained with reference to FIG. 2, which shows an electric resistance welded tube cut away in its longitudinal direction.

Transfer the steel strip l at a predetermined speed ■ and form the forming o-ru 4.
The copper strip is bent in a direction perpendicular to the longitudinal direction of the copper strip to form a groove shape into a cylindrical shape, with both sides of the copper strip facing each other, and the opposing edges are pulse TIG high frequency welded and pressurized with a squeeze roll 5. Then, the electric resistance welded tube 2 is formed and cooled by passing it through the cooling device 6.

9 indicates a welding point, and IO indicates a welded joint.

The pellet insertion device 3 for feeding the pellets 7 into the electric resistance welded tube 2 includes a hopper 3' that waits the pellets 7 in a line.
and a punching device 3'' provided at the bottom of the hopper 3' for punching out the pellets 7 that are successively descending from the hopper 3' and inserting them into the electric resistance welded tube 2. located close to.

Appropriate methods for punching out the pellets include a method using compressed air, a method using a plunger, a rotating roller, and the like. The pellets 7 continuously ejected by the pellet insertion device 3 slide on the copper strip, move at a speed V faster than the moving speed V of the steel strip 1, and enter the ERW pipe 2 along the pipe wall. enter in. In this way, the welding position of the ERW pipe (
At the welding point 9), the pellet 7 passes instantaneously at a speed faster than the welding speed, that is, the moving speed of the electric resistance welded pipe, so the pellet-shaped flux is not affected by welding heat to the extent that it changes in quality. , and since the flux is in the form of pellets, the phenomenon of flux adhering to the opposing edges of the copper strip formed in the circular tube, that is, the welding area, is completely prevented, and as a result, welding can be performed extremely well. Can be done.

The pellets 7 that have entered the ERW tube 2 collide with the pellets 7' loaded in series and are stopped (with respect to the tube), but at this time, as shown in the figure, the pellets 7 reach the ERW tube 2 from the steel strip l. If the entire process up to this point is tilted at an angle of inclination θ greater than the angle of repose of the pellets, an orderly loading state with no gaps between the pellets will be obtained, which is convenient for eliminating variations in the filling rate. Also, pellets 7' loaded in the ERW tube
In order to prevent the pellets 71 from being adversely affected by welding heat, it is necessary to maintain a predetermined distance between the end of the pellet 71 and the welding point 9, at least a distance equal to the inner diameter of the pipe. Set speed and feed interval.

The pellets are shaped into a circular tube according to the cross-sectional shape of the tube, and since the diameter can be determined as appropriate, there is an advantage that the filling rate can be designed over a wide range.

In the specific example shown in the figure, the pellets were fed into the electric resistance welded tube using forced means by the punching device 3'' of the insertion device 3, but as described above, the entire pellet feeding process was carried out at the angle of repose of the pellets. If the inclination is above, the pellets will slide on the copper band and enter the electric resistance welded pipe, so there is no need to use any forced means.

The ERW tube with pellets loaded in this way is
The wire is drawn with a roller die to reduce its diameter, which compresses the pellet, causing it to crumble and fill into the tube at a predetermined filling rate.After that, the ERW tube filled with flux is placed on a winding bobbin. It is wound up and sent to the next process.

Next ζ To explain this with reference to Figure 1 again, the pipe diameter is reduced to an intermediate diameter at wire drawing 0 →, and stress relief is performed during annealing, which also serves to remove the hydrogen source inside the cladding tube, which has an adverse effect on welding. Intermediate annealing is performed for this purpose, and the pipe diameter is further reduced by wire drawing (G).

Next, the plating process (the tube surface is plated with copper, and then the tube diameter is reduced to the final diameter by skin pass wire drawing. Then, the tube is wound in an aligned manner. It is loaded into a twill or pail pack, and becomes a flux-cored wire for welding as a product.

The above plating treatment (-1) steel plating is applied to the pipe for the purpose of preventing rust on its surface and improving conductivity during welding, but this point is similar to solid wire for welding, and the conventional seam is The above-mentioned problem is that plating cannot be performed with wires that have the same properties.Also, plating is not limited to copper plating;

It goes without saying that single metal plating of Ae+N1+Cr+Sn, Sn+Cu alloy plating, double plating of N1±Cr, etc. may be applied as long as the properties of the weld metal are not impaired.

Although pulsed TIG high-frequency welding is employed for electric resistance welding in the above description, the present invention is not limited to this, and any suitable electric resistance welding method may be used depending on the situation.

In addition to the method of supplying pellets into the ERW tube in the above-mentioned specific example, the pellet supply tube may be inserted into the D sewing tube, and the pellets may be fed and loaded into the ERW tube through the cough pellet supply tube. If you do this (1), it will be more effective to protect the pellet flux from welding heat.As for the material of this pellet supply pipe, quartz or ceramic is selected in consideration of heat resistance and thermal conductivity. good.

As explained above, the present invention has the advantage that the flux will not be adversely affected by the heat of welding during flux filling, and the welded area will not be adversely affected by the flux. At the same time, it is possible to set the filling rate over a wide range, which makes it possible to obtain products of good quality, and also to improve production efficiency.
Quru4J! ! ! The structure can be made by row 7.

[Brief explanation of drawings]

FIG. 1 is a flowchart showing a specific example of the manufacturing process related to the present invention, and FIG. 2 is a longitudinal cross-sectional view showing a specific example of the present invention, including the rack supply and pipe making steps. l: Steel strip 2: ERW tube 3: Pellet insertion device 3': Poso bar 3'': Embossing device 4: Forming r call 5
Nyquiz roll 7: Pellet flux 7'
: Pellet-shaped blackx loaded in the ERW tube Figure 1

Claims (1)

[Claims] A copper strip is formed into a cylindrical shape, and both edges of the copper strip are welded to form an ERW tube, and flux is supplied and filled into the ERW tube to form a flux-cored ERW tube. A method for manufacturing a flux-cored shear wire for welding by drawing the wire into a wire, the method comprising: forming the flux into pellets, and supplying and filling the pelletized flux into an electric resistance welding tube.