JPH0663791A - Production of powder and granular material filled pipe - Google Patents

Abstract

PURPOSE:To prevent the crack of the pipe by sticking of powder and granular materials to the edge surface of an aperture by humidifying the supplied powder and granular materials by water or an activator soln. CONSTITUTION:After a non-granulated flux 5 of a rutile system is packed in an open pipe 1 formed to a U shape, the mist of the water or the aq. soln. contg. a surfactant is sent in the amt. of 100 to 400ml/hour in terms of liquid volume into a chamber 17 to humidify the inside of the open pipe 1. The open pipe 1 passes fin pass rolls 6 and seam guide rolls 7 and enters a welding zone. The aperture is continuously welded by a high-frequency indication welding device 8. The pipe is thereafter subjected to one time of annealing in the middle and is diametrally reduced by rolling roll groups and is coiled after the pipe is subjected to annealing and plating. The pipe is then made into a product by finish drawing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a powder / granule-filled tube in which carbon steel, stainless steel, copper alloy, aluminum alloy or other metal tube is filled with the powder / granular material. here,
The powder or granular material means powder such as welding flux or oxide superconducting material, granular material or a mixture of powder and granular material.

This invention relates to a flux-cored wire for welding,
It is used to manufacture wires containing oxide superconducting material and other powder-filled tubes.

[0003]

2. Description of the Related Art A flux-cored wire for welding is one type of powder-filled tube. In the production of this wire, a cold-rolled steel strip is slit by a required width, and the slit steel strip is gradually formed from a U-shape to an O-shape by a forming roll.
During this forming, a flux having a desired component such as a metal powder such as iron powder, a deoxidizing agent and an arc stabilizer is supplied to a steel strip valley portion from an opening along the longitudinal direction of the U-shaped steel strip by a feeder. Then, while forming into an O-shape, the opposite edge surfaces of the opening are joined by welding, and the diameter is subsequently reduced. Further, after annealing if necessary, the tube filled with the flux is drawn into a desired diameter and wound up to obtain a product.

As the welding method in the manufacture of the powder-filled tube, there are TIG welding, plasma welding, electron beam welding and the like, but the high frequency induction welding method is generally widely used. This welding method heats the edge surface of the opening to the melting temperature by induction heating by the high frequency current flowing in the induction heating coil (work coil), and presses the opposing edge surfaces with a pair of squeeze rolls, after forming into a substantially O-shape. To do.

In any of the welding methods, when the welded pipe is reduced in diameter by rolling, wire drawing or the like after filling the flux, cracks may occur in the pipe outer cover. And the cause of this crack is considered as follows.
Dust generated when the flux is supplied rises and adheres to the opening edge surface. Also, the magnetic field generated by the welding current during welding causes the opening edge portion of the tubular body to become a magnetic pole, and the magnetic powder component in the flux is adsorbed to the opening edge portion by the magnetic force. At this time, the non-magnetic component is also attached to the opening edge portion along with the magnetic component. In this way, the flux attached to the opening edge portion melts into the welded portion and becomes an inclusion. Then, due to this inclusion, a crack occurs when the diameter is reduced. The cracks when the diameter is reduced are directly brought into the product, that is, the flux-cored wire for welding, and deteriorate the welding workability.

As one of the techniques for solving such a problem, there is a "composite pipe manufacturing method" disclosed in Japanese Patent Laid-Open No. 63-5897, which removes fine powder finer than 48 mesh at the time of powder supply. However, the fine powder is prevented from adhering to the opening edge portion. In addition, there is a "method for manufacturing a filler wire" in JP-A-60-234792, in which a non-magnetic material is dispersed in an upper layer and a magnetic material or a ferrite-based material is dispersed in a lower layer to form a non-magnetic material layer in an upper layer. The ferromagnetic material or the ferrite-based material is suppressed from being attracted to the opening edge portion.

[0007]

However, even if the joint welding portion is improved by the above-mentioned conventional technique, the cracks as described above still occur when the diameter of the pipe is reduced, and the product yield is lowered. Once the cracks occur, even if the cracks are minute at first, the cracks extend in the longitudinal direction of the pipe as the reduced diameter size of the pipe becomes smaller, and the length becomes a length that cannot be ignored in the product size.

[0008] Therefore, an object of the present invention is to provide a method for manufacturing a powder-granule-filled pipe of good quality without cracks in the pipe shell by obtaining a sound joint weld.

[0009]

The method of manufacturing a powder-filled tube according to the present invention is characterized in that a metal strip is fed in the longitudinal direction of the tube and a void is left along the tube until at least the welding point. The metal strip is formed into a tubular shape while the powder particles are being supplied to, and the opposite edge surfaces of the openings extending along the longitudinal direction of the tube are welded.

In the above manufacturing process, the inside of the tube is humidified after the powdery material is supplied into the tube. As the liquid to be humidified, water or a liquid in which one or more kinds of surfactants are dissolved in water (hereinafter referred to as an active agent solution) is used.

To humidify the inside of the pipe, water or the activator solution is obtained by a method such as ultrasonic vibration of the water or the activator solution, atomization with compressed air, or generation of steam in the boiler. The steam is directly sent in the longitudinal direction of the pipe for humidification. Alternatively, a method is used in which a mist of water or an activator solution obtained by the above method or vapors thereof is fed into a chamber enclosing an open tube to humidify the inside of the tube. As the surfactant dissolved in water, there are cationic, anionic, nonionic, amphoteric, silicon and fluorine type surfactants, and any of them may be used. Further, the amount of dissolution in water is preferably 3 to 20%.

[0012]

The dust in the pipe that rises up when the powder and granules are supplied is moistened by the mist of water or the activator solution or their vapors, becomes heavy, and sinks into the pipe. Further, the particles in the pipe are humidified, and the particles are bonded to each other, so that the particles do not rise due to the influence of the magnetic force generated by the welding current during welding. Therefore, the cracking of the tube due to the attachment or magnetic attachment of the powdery particles to the opening edge surface is substantially eliminated.

[0013]

EXAMPLES The manufacturing of flux-cored wires for welding will be described below as examples. FIG. 1 is a configuration diagram of a main part of a wire manufacturing apparatus. As shown in FIG. 1, a forming roll group 2, a side roll 3, and a flux supply device 4 are arranged along the feed direction of the open pipe 1. A preforming roll (not shown) is provided on the upstream side of the forming roll 2. The flux 5 is supplied from the space between the side rolls 3 to the open pipe 1 in the middle of molding. The open pipe 1 supplied with the flux 5 passes through the fin pass roll 6 and the seam guide roll 7 and enters the welding zone. The high frequency induction welding device 8 includes a work coil 9 and a squeeze roll 10. A high frequency welding current is supplied to the work coil 9 from a power source 11. Welded pipe 1
As for No. 2, the external bead 14 on the outer surface side is cut by the cutting tool 13 and rolled by the rolling roll group 15, and while being annealed, the outer diameter is 1.0 to 2 by the rolling device and the wire drawing device (neither is shown). Reduced to a product size of 0.0 mm.

According to the present invention, in such a wire manufacturing apparatus, mist of water or activator solution or vapors thereof is further introduced into the open pipe 1 to which the flux 5 is supplied between the side roll 3 and the fin pass roll 6. It is equipped with means for sending and humidifying. A mist or steam generator 16 of FIG. 1 is used to generate mist or steam, and the mist or steam is sent into the chamber 17 to drop dust that has risen during the flux supply into the open pipe 1 and humidify the flux 5 in the open pipe. To do. FIG. 2 is a front view showing an example of a device for humidifying the inside of the open pipe 1 in the chamber 7. In the figure, reference numeral 1
Reference numeral 8 is a water or aqueous solution drainage for discharging the condensed water or aqueous solution of the excess mist or steam.

Here, the production results of the flux-cored wire for welding produced by the apparatus configured as shown in FIG. 1 will be described. The humidification was performed by generating fog with an ultrasonic humidifier.

Steel strip having a plate thickness of 2.2 mm and a width of 65.5 mm (SP
HCC 0.05%) was molded into a tube with an outer diameter of 22.4 mm. During molding, a rutile non-granulated flux is supplied into the open pipe so that the filling rate is 10 to 14%, and after the flux is supplied, mist of water or an aqueous solution containing a surfactant is 100 to 400 ml / After sending it into the hr chamber and humidifying the inside of the open pipe, the open pipe was continuously welded by high frequency induction welding. At this time, the frequency of the high frequency current supplied to the work coil was 520 kHz, and the welding speed was 30 m / min. The welded pipe having an outer diameter of 22.4 mm was annealed once with a group of rolling rolls to reduce the outer diameter to 3.2 mm, annealed, plated, and wound into a coil. Then, finish drawing was carried out and the occurrence of cracks in the product wire having an outer diameter of 1.2 mm was examined.

The results are shown in Table 1.

[0018]

[Table 1]

The cracks were evaluated by conducting an eddy current flaw detection test (ECT) on the wire sheath over the entire length of 100 km of the product wire having an outer diameter of 1.2 mm after wire drawing (spool of 20 kg of wire × 37) to determine the presence and position of cracks. It was carried out by observing and checking the presence of cracks in the wire longitudinal direction by observing the relevant part with a magnifying glass when a cracking signal was output. When the presence of cracks could not be confirmed at all, this was regarded as good. When the occurrence of cracks was confirmed even in one place, this was regarded as a defect.

In Table 1, the experiment No. 1 to 4 are examples of the present invention, in which the inside of the open pipe is humidified. In these experimental examples, cracking did not occur, and the amount of diffusible hydrogen, which is feared to increase by humidifying the inside of the open pipe, is about the same value as when there is no humidification, and the quality of the product wire is good, When welding was performed using a wire containing flux for welding, good welding workability was achieved.

On the other hand, in Experiment No. No. 5 is a comparative example, and since the inside of the open pipe is not humidified, the dust that rises up during the flux supply and the flux that rises up due to the magnetic force generated by the welding current during welding adhere to or are adsorbed at the edge of the open pipe, resulting in cracking. And reduced the product yield.

[0022]

According to the present invention, as described above, the dust in the pipe that has risen up during the supply of the powder or granular material is dropped into the open pipe by the mist of water or an aqueous solution containing a surfactant, or their vapors, to be dropped into the open pipe. Since the powder and granules in the pipe are humidified, the powder and granules are bonded to each other, and the powder and granules are not soared by the magnetic force generated by the high frequency welding.

Therefore, the cracking of the outer shell of the tube caused by the adhesion and adsorption of the powder particles on the edge surface of the open tube is substantially eliminated. As a result, the product yield can be improved, and a powder-filled tube with good quality can be obtained.

[Brief description of drawings]

FIG. 1 shows an embodiment of the present invention and is a configuration diagram of a main part of a manufacturing apparatus for a flux-cored wire for welding.

FIG. 2 is a front view showing an example of a device for humidifying the inside of an oven tube in the chamber of FIG.

[Explanation of symbols]

 1 Open Pipe 2 Forming Roll Group 3 Side Roll 4 Flux Supply Device 5 Flux 6 Fin Pass Roll 7 Seam Guide Roll 8 High Frequency Induction Welding Device 9 Work Coil 10 Squeeze Roll 11 Power Supply 12 Welded Pipe 13 Cutting Bit 14 Excessive Beat 15 Rolling roll group 16 Fog or steam generator 17 Chamber 18 Water or aqueous solution removal

Claims (2)

[Claims] 1. A metal strip plate is formed into a tubular shape while feeding the metal strip plate in the longitudinal direction of the metal strip plate while supplying a powder or granular material into the pipe so as to leave a gap along the pipe up to at least a welding point. Then, in the method of manufacturing a powder-and-granule-filled pipe by welding the opposite edge surfaces of the openings extending along the pipe longitudinal direction,
A method for producing a powder / granule-filled tube, which comprises humidifying the inside of the tube after supplying the powder / granular material into the tube. 2. The method for producing a powder-and-granule-filled tube according to claim 1, wherein the moistening liquid is a mixture of one or more surfactants dissolved in water.