JPH06126486A - Manufacture of filling tube for granular body - Google Patents

Abstract

PURPOSE:To obtain the manufacture of a filling tube, which is free from crack on the outer casing of the tube and is good in quality, for granular body by obtaining a sound joined welding part. CONSTITUTION:In the manufacture of the filling tube for granular body in which granular bodies 5 are supplied to a tubular body 1 during the formation of a tubular body 1 from a steel belt, both edges of the tubular body 1 are joined, and the diameter is reduced of the welded tube 12 filled with the granular body 5; following the supply of the granular body, after one, two or more kinds of moisture absorption accelerator 19 is supplied for scattering or after the granular body 5 containing one, two or more kinds of moisture absorption accelerator 19 are supplied; the inside of the open tube 1 is humidified by mist or vapor. Thus, the dust generated at the time of supplying the granular body is settled inside the tube, and also the granular body 5 is prevented from soaring due to the magnetic force generated by welding. Consequently, the crack on the outer casing of the tube, which is caused by the granular body 5 sticking and absorbing to the edge of the open tube 1, is practically eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flux cored wire for welding in which metal powder such as carbon steel, stainless steel, copper alloy, aluminum alloy or the like is filled with powder or granular material, wire containing oxide superconducting material or other powder or granular material. It relates to a method of manufacturing a tube. 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.

[0002]

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 to obtain a product.

As a 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 the 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 forms a pair of squeeze rolls on opposite edge surfaces. Press with.

In the step of cold-rolling the tube in which the flux is filled immediately after welding, a two-roll or three-roll hole type roll row is installed in continuous rolling stands of a plurality of stages. 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, when the pipe welded after being filled with the flux is reduced in diameter by rolling, wire drawing or the like, cracks may occur in the outer skin of the pipe.
The cause of this crack is considered as follows.

Dust generated when the flux 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 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.

As described above, the flux attached to the opening edge portion melts into the welded portion and becomes an inclusion. Then, 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. When powder is supplied, fine powder finer than 48 mesh is opened. 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.

[0009]

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, an object of the present invention is to provide a powder-filled tube in which the outer shell of the tube is not cracked by obtaining a sound welded joint.

[0011]

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 the method for producing a powder-and-granule-filled tube by performing diameter reduction and annealing, after supplying the powder or granules, one or more kinds of moisture absorption promoters are sprinkled and supplied onto the surface of the powder or granules. The point is to weld the pipe after humidifying the inside of the pipe.

The second invention is one or two of moisture absorption promoting agents.
The gist of the present invention is to supply the powder or granules containing at least one seed and then humidify the inside of the open pipe before welding the pipe.

To humidify the inside of the open pipe, water is atomized by ultrasonic vibration, compressed air or the like, or mist or steam obtained by a method of generating steam in a boiler is directly fed into the pipe for humidification. Alternatively, a method may be used in which the mist or vapor obtained by the above method is fed into a chamber enclosing an open tube to humidify the chamber.

The hygroscopic agent is potassium silicate or sodium silicate.
Da, potash glass, soda glass, sodium borate, bainite, starch, dextrin, soda alginate,
A single substance such as CMC or a mixture thereof is shown. Further, it is preferable that the amount of the hygroscopicity-promoting agent supplied after the supply of the powder or granules to be applied or mixed with the powder or the powder is 0.1 to 5.0%.

[0015]

[Operation] The dust in the pipe that has risen up when the powder or granular material is supplied is humidified by mist or steam, becomes heavy, and settles in the pipe. Next, the moisture absorption promoter on the surface of the powder or granules is humidified to form a band-shaped film to cover the powder or granules in the pipe, and the powder or granules containing the magnetic powder rise under the influence of the magnetic force generated by the high-frequency welding current during welding. Absent.

The second invention is one or two of moisture absorption promoting agents.
By supplying the granules containing more than one seed and then moistening the inside of the open pipe with mist or steam, the dust in the pipes that rises up during the supply of the granules becomes heavy and settles in the pipes. The moisture absorption promoting agent is humidified to form a coagulated and solidified film and is integrated with the powder and granules, and the powder and granules containing the magnetic powder do not rise due to the influence of the magnetic force generated by the high frequency current during welding.

Therefore, the cracking of the tube due to the adhesion of the powdery particles to the opening edge surface or the magnetic attachment is substantially eliminated.

[0018] It should be noted that if one or more kinds of moisture absorption promoters are supplied or contained only in the granular material after the granular material is supplied, it is not possible to settle the dust that floats up during the supply of the granular material. During welding, the magnetic powder in the open pipe flies up.

[0019]

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. A forming roll group 2, a side roll 3, and a flux supply device 41 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. 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.
Between the flux supply device 41 and the moisture absorption promoter 1
9 is provided with a means for supplying mist or steam to the chamber 17 to humidify the inside of the open pipe. The chamber 17 is supplied with mist or steam from the mist or steam generator 16.

When the flux contains a moisture absorption promoter, the supply device 42 is unnecessary.

FIG. 2 is a front view showing an example of an apparatus for moisturizing the inside of an open pipe after supplying a flux of a moisture absorption promoter or supplying a flux containing a moisture absorption promoter after the flux is supplied. In the figure, reference numeral 18 is a water or aqueous solution drainer for discharging the mist or excess water or aqueous solution condensed from the above.

Here, the result of manufacturing the flux-cored wire for welding by the apparatus of FIG. 1 configured as above will be described. While feeding the steel strip in the longitudinal direction of the steel strip, it is formed into an open pipe of U to O cross section by a forming roll. During this forming, the flux is supplied from the opening of the open pipe and the moisture absorption is promoted. The mixture is sprayed with one or a mixture of two or more agents, and then humidified. Or 1 of the moisture absorption promoter
A seed or a flux containing two or more species is supplied and then humidified.

The steel strip used is a carbon steel strip (JIS S
PHC) was used to form a tube having a plate thickness of 2.2 mm and a width of 65.5 mm and an outer diameter of 22.4 mm, and the edge surfaces opposite to each other were joined by high frequency induction welding (frequency 520 kHz, welding speed 30 m / min).

The flux used was a rutile non-granulated flux containing magnetic powder shown in Table 1 and having a mesh size of 32 mesh or less, and was supplied into the open pipe at a target filling rate of 12.0 ± 0.5%. In Table 1, the flux symbol F1 is an example containing no moisture absorption promoter, and the fluxes F2 and F3 are examples containing a moisture absorption promoter.

[0027]

[Table 1] For humidification, a mist was generated by ultrasonic vibration, and the mist was fed into the chamber at 75 to 350 ml / hr in terms of water amount.

The welded pipe having an outer diameter of 22.4 mm was annealed once by a rolling roll group to reduce the outer diameter to 3.2 mm, further annealed and plated, and wound into a coil. Next, finish wire drawing was performed and the occurrence of cracks on the product wire with an outer diameter of 1.2 mm was examined.

Moisture in the wire due to the humidification is released to the outside of the tube by heating in the two annealing steps.

The above results are shown in Table 2.

[Table 2] The evaluation of cracking is made by using a product wire 100 with an outer diameter of 1.2 mm after drawing.
Perform the eddy current flaw detection test (ECT) of the wire sheath over the entire length of the km (20 kg wire spool, 37 coils) to confirm the presence and location of cracks, and observe the relevant part with a magnifying glass when a crack signal is output. Then, it was carried out by confirming the presence of cracks in the wire longitudinal direction. 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 2, Test Examples 1 to 4 are examples of the present invention. Test Examples 1 and 2 are examples in which the moisture absorption promoter is sprayed and supplied after the flux is supplied, and Test Examples 3 and 4 are examples in which the flux-containing material is supplied and then humidified. In these test examples, there is no occurrence of cracking, and the diffusible hydrogen amount that is concerned by humidification is the same value as when neither is humidified, and when welding was performed using the product wire,
Good workability was achieved.

On the other hand, Test Examples 5 to 7 are comparative examples, and Test Example 5 does not contain a moisture absorption promoter in the flux F1 and is not humidified. During the welding, the granular materials that were soared by the magnetic force generated by the high-frequency welding current adhered to or adsorbed to the edge of the open pipe, resulting in cracking, which reduced the product yield.

In Test Example 6, the flux F was used although humidified.
1 does not contain a moisture absorption promoter, and since the moisture absorption promoter was not supplied following the supply of the flux F1, the magnetic powder during welding caused powder particles to rise and adsorb on the edge of the open pipe, causing cracking. .

In Test Example 7, the flux F3 contained a hygroscopic agent, but since it was not humidified, the powder and granules soared when the flux was supplied and the powder and granules soared by the magnetic force during welding were opened. As a result of adhesion or adsorption to the edge, cracking occurred and the product yield was reduced.

[0035]

According to the present invention, as described above, after supplying the powdery or granular material, the moisture absorption promoting agent is sprinkled and supplied, or the powdery or granular material containing the moisture absorption promoting agent is supplied, and then humidified by mist or steam. As a result, the powder particles that have risen up when the powder particles are supplied settle down, and the powder particles cannot rise even by the magnetic force generated during welding.

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 is a front view showing an example of a device for humidifying the flux in the open pipe.

[Explanation of Codes] 1 Open Tube 2 Forming Roll Group 3 Side Roll 41 Flux Supply Device 42 Moisture Absorption Promoter 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 16 Fog or steam generator 17 Chamber 18 Draining 19 Moisture absorption promoter

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yasuhiko Hatada 4-2-1 Asae, Hikari-shi, Yamaguchi Nittetsu Welding Industry Co., Ltd. Hikari Factory (72) Inventor Toyo Kanamori 4-chome, Asae, Hikari-shi, Yamaguchi Prefecture No. 1 Nittetsu Welding Industry Co., Ltd. Hikari Factory

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 the above, the powder is characterized in that one or more kinds of moisture absorption promoters are sprinkled and supplied onto the surface of the granular material after the supply of the granular material, the inside of the open pipe is humidified, and then the pipe is welded. A method for manufacturing a granular filling tube. 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. 2. A method for producing a powder-granule-filled tube, comprising supplying a powder-granular material containing one or more kinds of moisture absorption promoters, humidifying the inside of an open pipe, and then welding the pipe.