JPH0671482A - Production of pipe filled with powder and granular material - Google Patents

Abstract

PURPOSE:To provide the pipe filled with powder and granular materials having good quality without having cracks in the sheath of the pipe by humidifying the inside of an open pipe with steam after supply of the powder and granular materials thereto, then coating the surfaces of the powder and granular materials with a paper tape. CONSTITUTION:The mist of water or aq. surfactant soln. or the vapor thereof is fed into a chamber 17 to humidify the inside of the open pipe supplied with a flux 5 between side rolls 3 and fin pass rolls 6. The paper tape 22 is supplied from a paper tape supply reel 21 via a guide member 20 into the humidified open pipe to coat the surfaces of the humidified powder and granular materials with the paper tape. As a result the crack of the sheath of the pipe occurring in the adhesion and adsorption of the powder and granular materials to the edge surfaces of the open pipe is prevented.

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 predetermined 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 or a deoxidizer and an arc stabilizer is fed to the valley portion of the steel strip through a feeder from an opening along the longitudinal direction of the U-shaped steel strip. Supply. Then, while forming into an O-shape, the opposite edge surfaces of the opening are joined by welding, and the diameter is subsequently reduced. Furthermore, 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 above-mentioned 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 a melting temperature by induction heating by a high frequency current flowing in an induction heating coil (work coil) when it is formed into a substantially O shape, and the opposite edge surfaces are paired with a squeeze roll. Press with.

Then, in the process of cold rolling the tube in which the flux is filled immediately after welding, a two-roll or three-roll hole type roll row incorporated in a plurality of continuous rolling stands. In this way, the outer diameter of the pipe is reduced and the diameter is reduced to a desired diameter.

By the way, in any of the above welding methods, cracks may occur in the outer shell of the pipe when the pipe welded after being filled with flux is reduced in diameter by rolling, wire drawing or the like.

The cause of this crack is considered as follows. The dust generated when the Lux is supplied rises and adheres to the opening edge surface. Further, the opening edge portion of the tubular body serves as a magnetic pole due to the magnetic field generated by the welding current during welding, and the magnetic powder component in the flux is attracted to the opening edge portion due to the magnetic force. At this time, the non-magnetic component is also attached to the opening edge portion along with the magnetic component.

As described above, the flux attached to the opening edge portion melts into the welded portion and becomes an inclusion. The inclusions cause cracks 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, in which fine powder finer than 48 mesh is opened when powder is supplied. Prevents adhesion to the edge. In addition, there is "a method for manufacturing a filler wire" in Japanese Patent Laid-Open No. 60-234792, in which a nonmagnetic material is dispersed in an upper layer and a magnetic material or a ferrite-based material is dispersed in a lower layer to form an upper nonmagnetic material layer. Prevents the ferromagnetic material or the ferrite-based material from being attracted to the opening edge portion.

[0010]

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.

Therefore, it is an object of the present invention to provide a method for producing a powder / granule-filled pipe having no cracks in the pipe shell by obtaining a sound welded joint.

[0012]

The method for producing a powder-filled tube according to the present invention is such that a metal strip is continuously formed into an open tube by a forming roll while being fed in the longitudinal direction thereof. During molding, powder is supplied from the opening of the open pipe so as to leave a gap along the pipe, and the opposing opening edge surfaces of the open pipe are butt-welded together to the pipe obtained by welding. In a method for producing a powder-and-granule-filled tube by performing diameter reduction and annealing, after supplying the powder and granules, after humidifying the inside of the open pipe, a paper tape is supplied into the open pipe and the powder-grains are supplied. It is characterized in that the pipe is welded after the body is covered.

A second aspect of the invention is, after the powder and granules are supplied, a paper tape is supplied into the open pipe to cover the powder and granules, and then the tape is opened.
It is characterized in that the inside of the Pun pipe is humidified before the pipe is welded. Humidification in the open pipe is performed by using water or a cationic system in water,
Obtained by a method in which anionic, nonionic, silicon, fluorine-containing surface active agent is dissolved in about 3 to 20% by a method such as ultrasonic vibration, atomized with compressed air, or steam generated by a boiler. The mist or steam of the obtained water or the aqueous solution of the surfactant is sent directly into the pipe for humidification. Alternatively, a method may be used in which the mist or steam obtained by the above method is fed into a chamber that encloses an open tube to humidify the chamber.

As the paper tape, water-absorbent thin paper or household thin paper is used. It is preferable that the weight of the paper tape is 40 g / m ² or less, and the width is a width that covers the entire powder and granules in the open pipe and is in contact with both walls of the open pipe.

[0015]

The dust in the pipe that rises up during the supply of the granular material is humidified by the mist of the water or the aqueous solution of the surfactant or their vapors, becomes heavy, and settles in the pipe. Then, the surface of the moistened powder or granular material is covered with a paper tape so that the continuously supplied paper tape covers the powder or granular material in the pipe and the influence of the magnetic force generated by the high-frequency welding current during welding. As a result, the granular material containing magnetic powder does not fly up.

A second aspect of the invention is to continuously supply a paper tape into the open tube after supplying the granular material, and then to the inside of the open tube by mist of water or a surfactant aqueous solution or their vapor. By humidifying, the dust in the pipe that rose when supplying the granular material became heavy and settled in the pipe, and when the paper tape was humidified, it became integrated with the granular material and was generated by the high-frequency current during welding. Due to the influence of magnetic force, powder particles containing magnetic powder do not rise. 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.

It should be noted that the dust that has risen during the supply of the granules cannot be settled only by covering the granules with the paper tape, and the magnetic powder in the open pipe is struck from both sides of the paper tape. Soar up.

[0018]

EXAMPLES The manufacturing of flux-cored wires for welding will be described below as examples.

FIGS. 1 and 2 are block diagrams of the main parts of the wire manufacturing apparatus. Forming roll along the feed direction of the open pipe 1.
The roll group 2, the side rolls 3, and the flux supply device 4 are arranged. A preforming roll is provided on the upstream side of the forming roll 2.
(Not shown) is provided. From between the side rolls 3 and the side rolls 3, the flux 5 is supplied to the open pipe 1 which is being formed. The open pipe 1 supplied with the flux 5 passes through a fin pass roll 6 and a seam guide roll 7 and enters a welding zone.

The high frequency induction welding device 8 is provided with a work coil 9 and a squeeze roll 10. Work coil 9
A high-frequency current is supplied to the power source 11 from the power source 11. The welded pipe 12 is provided with a cutting bit 13 and an extra bead 14 on the outer surface side.
Is cut and rolled by the rolling roll group 15, and while being annealed, the diameter is reduced to a product size of 1.0 to 2.0 mm by a rolling device and a wire drawing device (neither is shown).

According to the present invention, in such a wire manufacturing apparatus, a side roll 3 and a fin pass roll 6 are further provided.
And a means for humidifying the inside of the open pipe by sending a mist of water or an aqueous solution of a surfactant or a vapor thereof to the chamber 17 into which the flux 5 is supplied.
A tape supply device 19 is arranged, and has means for supplying a paper tape 22 from a paper tape supply reel 21 through a guide member 20 into a humidified open pipe. In the figure, reference numeral 1
Reference numeral 8 is a water or aqueous solution vent for discharging excess water or aqueous solution in which mist or steam has condensed.

In FIG. 2, after the paper tape 22 is supplied to the open pipe 1 to which the flux 5 is supplied, the inside of the open pipe is humidified. FIG. 3 is a front view showing an example of a device for humidifying the flux 5 in the open pipe. Fig. 4 shows the paper tape in the open pipe.
It is a perspective view which shows the example of a device which sends a lump.

Here, the result of manufacturing the flux-cored wire for welding by the apparatus of FIGS. 1 and 2 configured as above will be described. While feeding the steel strip in its longitudinal direction, it is formed into an open pipe of U to O cross section by a forming roll, and flux is supplied from the opening of the open pipe in the middle of this forming, followed by humidification. After that, a paper tape is supplied. Alternatively, the flux is supplied, and the paper tape is supplied and then humidified.

The steel strip used is a carbon steel strip (JIS S
(PHC) with a plate thickness of 2.2 mm and a width of 65.5 mm, formed into a pipe with an outer diameter of 22.4 mm, and the opposite edge surfaces of the opening are subjected to high frequency induction welding (frequency 520 kHz, welding speed 30).
m / min).

The flux is made of ferromagnetic metal powder 15
% Of the rutile-based non-granulating flux containing 32% or less was used, and it was supplied into the open pipe at a target filling rate of 12.0 ± 0.5%.

For humidification, steam was generated by a boiler, and the steam was fed into the chamber in the amount of water of 75 to 350 ml / hr. Paper tape is a thin paper roll, weighing 22 g /
A m ² and a width of 23 mm were used.

A welded tube having an outer diameter of 22.4 mm was rolled and rolled.
One annealing was performed on the way by means of a group of rollers to reduce the outer diameter to 3.2 mm, further annealing and plating were performed, and the coil was wound. Then, finish wire drawing was performed, and the occurrence of cracks in the product wire having an outer diameter of 1.2 mm was examined.

The paper tape supplied into the open pipe is carbonized by high temperature heating in the subsequent annealing furnace after the cold rolling process, and is uniformly distributed in the longitudinal direction of the pipe in the subsequent second diameter reducing process. Spread. At the same time, hydrogen and oxygen generated by heating are combined with the tube skin component or powder and remain in the tube partially, and are also partially discharged from the tube shell to the outside by the heating in the subsequent second annealing step. To be done. The water content in the wire due to the supply and humidification of the paper tape is about 2 to 7 ppm in terms of hydrogen with respect to the total weight of the wire, and this hydrogen is released outside the tube by annealing as described above. Further, the amount of C in the wire carbonized by supplying the paper tape was 1 ppm or less with respect to the total weight of the wire, and there was no influence on the welding workability and the mechanical properties of the weld metal.

The above results are shown in Table 1.

[Table 1]

The cracks were evaluated by 100 km of a product wire having an outer diameter of 1.2 mm after wire drawing (20 kg of wire spool).
The presence of cracks in the longitudinal direction of the wire is confirmed by performing an eddy current flaw detection test (ECT) on the wire sheath over the entire length of the coil (37 coil) to confirm the presence and position of the crack, and when a crack signal is output, observe the relevant part with a magnifying glass It was carried out by checking. 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, Experiment Nos. 1 to 4 are examples of the present invention, in which a flux is humidified and then a paper tape is supplied, or a paper tape is supplied and then humidified. In these experimental examples, no cracks were generated, and the amount of diffusible hydrogen that is concerned about by supplying humidifying and feeding paper tape was the same value as when neither was carried out. When welding was performed, good workability was achieved.

On the other hand, Examples 5 to 7 are comparative examples, and since Example 5 is not supplied with humidification and paper tape, powder particles rising at the time of flux supply and high frequency welding at welding. The flux rising by the magnetic force generated by the electric current adhered to or adsorbed on the edge of the open pipe, resulting in cracking, which reduced the product yield.

In Example 6, since the paper tape was not supplied although it was humidified, the magnetic flux at the time of welding caused the flux to rise, and the flux was adsorbed at the edge of the open pipe and cracked.

In Example 7, since the paper tape was supplied but not humidified, the powder and granular material that flew up when the flux was supplied and the flax that flew up from both sides of the paper tape due to the magnetic force during welding. -As a result of adhesion or adsorption to the edge of the punnel, cracking occurred, reducing the product yield.

[0035]

According to the present invention, as described above, after the powder or granular material is supplied, the inside of the pipe is humidified with mist of water or an aqueous solution of a surfactant or steam thereof, and then the surface of the moistened granular material is paper tape. Cover with. Alternatively, by covering the surface of the granular material with a paper tape and then humidifying the granular material, the granular material that has risen up during the supply of the granular material settles down, and the magnetic force generated during welding prevents the granular material from rising.

Therefore, the cracking of the pipe envelope due to the adhesion and adsorption of the powder particles on the edge surface of the open pipe 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 shows another 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. 3 is a front view showing an example of a device for humidifying the flux in the open pipe.

FIG. 4 is a perspective view showing an example of a device for supplying a paper tape into an open pipe.

[Explanation of symbols]

 1 Open Tube 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 tool 14 Extra bead 15 Rolling roll group 16 Fog or steam generator 17 Chamber 18 Draining 19 Paper tape supplying device 20 Guide member 21 Paper tape supplying reel 22 Paper tape The

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toyo Kanamori 4-2-1 Asae, Hikari City, Yamaguchi Prefecture

Claims (2)

[Claims] 1. A metal strip is continuously formed into an open pipe by a forming roll while being fed in the longitudinal direction thereof, and a void is formed along the pipe from the opening of the open pipe during the forming. A method of manufacturing a powder-and-granule-filled tube by supplying powder and granules so as to leave them, butt-welding the opposing opening edge surfaces of the open pipe, and performing diameter reduction and annealing on the pipe obtained by the welding. In addition, after the supply of the powdery or granular material, after the inside of the open pipe is humidified, a paper tape is supplied into the openable pipe to weld the rear pipe covered with the powdery or granular material. Body filling tube manufacturing method. 2. A metal strip is continuously formed into an open pipe by a forming roll while being fed in the longitudinal direction thereof, and a gap is formed along the pipe from the opening of the open pipe during the forming. A method of manufacturing a powder-and-granule-filled tube by supplying powder and granules so as to leave them, butt-welding the opposing opening edge surfaces of the open pipe, and performing diameter reduction and annealing on the pipe obtained by the welding. In the following, the powder particles are characterized in that, after the supply of the powder and granular material, the paper tape is supplied into the open tube and the powder and granular materials are covered, and then the inside of the open tube is humidified and then the tube is welded. Body filling tube manufacturing method.