JPH0751891A - Production of powdery and granular material filled pipe - Google Patents

Abstract

PURPOSE:To provide a process for production of the powdery and granular material filled pipe which is free from crack in the pipe sheath by obtaining a deflectless joined weld zone. CONSTITUTION:The powdery and granular materials composed of ferromagnetic raw material powders and weak magnetic raw material powders at a prescribed compounding ration are used as the basic prescription of the powdery and granular materials in the process for production of the powdery and granular material filled pipe by supplying the powdery and granular materials into a tubular body 1 during the course of forming a metallic strip to the tubular body 1, joining both edge surfaces 2 of the tubular body by high-frequency welding and reducing the diameter of the welded pipe filled with the powdery and granular materials. The powdery and granular materials are supplied to the tubular body 1 by disposing the first kind divided prescription materials F1 of the plural divided prescription materials constituted by at least bisecting the basic prescription described above to the first kind divided prescription materials F1 compounded with the ferromagnetic raw material powders and the weak magnetic raw material powders and the second kind divided prescription material F2 compounded with the weak magnetic raw material powders on the lower layer side and disposing the second kind divided prescription materials F2 thereof on the upper layer side. The compounding ratio of the weak magnetic raw material powders with each other in the first kind divided prescription materials and the second kind divided prescription materials is set as the compounding ratio of the weak magnetic raw material powders with each other in the basic prescription materials F.

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 granular material refers to a granular material such as welding flux, oxide superconductor, and additive for molten steel.

[0002]

2. Description of the Related Art A flux-cored seamless wire for welding is one type of powder-filled tube. In the production of this seamless wire, the strip steel is slit to the required width,
The strip steel after slitting is gradually formed from a U-shape to an O-shape by a forming roll. During this forming, the flux is supplied from the opening along the longitudinal direction of the U-shaped strip steel to the strip steel valley portion by the 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 a welding method in the production of the above flux-cored wire for welding, high-frequency induction welding, high-frequency resistance welding and other high-frequency welding are widely used. In all of these welding methods, when formed into a substantially O-shape, the edge surface of the opening is heated to the melting temperature by Joule heat generated by the high-frequency current, and the opposing edge surfaces are pressed by a pair of squeeze rolls.

By the way, when the diameter of a tube filled with flux and welded is reduced by rolling, wire drawing, or the like, cracks may occur in the outer shell of the tube. The cause of this crack is considered as follows. During welding, some of the flux particles are adsorbed on the opening edge surface of the tubular body. That is, at the welding position, the opening edge of the tubular body becomes a magnetic pole due to the magnetic field generated by the welding current. Therefore, the ferromagnetic component of the flux particles is attracted by the magnetic force and adsorbed to the opening edge portion. At this time, the weak magnetic component is also attracted to the opening edge portion along with the ferromagnetic component. The flux particles adsorbed on these opening edge portions become inclusions in the welded joints and cause welding defects. Then, due to this welding defect, cracking occurs when the pipe diameter is reduced. The cracks when the diameter is reduced are directly introduced into the product, that is, the flux-cored wire for welding, and deteriorate the welding workability.

One of the techniques for solving such a problem is "a method for producing a tube filled with powder" disclosed in Japanese Patent Laid-Open No. 54-109040. This technique supplies powder so that it does not fill the tubular body, and creates a gap or distance between the joint weld and the surface of the powder layer that has been supplied, so that the powder rises and reaches the opening edge. I try not to. There is a "composite wire for welding" disclosed in Japanese Patent Application Laid-Open No. 60-234794, which is filled with substantially non-magnetic powder of a powder raw material having a relative magnetic permeability of 1.10 or less, and the powder is magnetically attracted. It is prevented from sticking to the opening edge portion by force. Also, there is a "method for producing a filler wire" in Japanese Patent Laid-Open No. 60-234792, in which a non-magnetic material is dispersed in an upper layer in a layered manner and a ferromagnetic material or a ferrite-based material is dispersed in a lower layer, and the non-magnetic material layer in the upper layer enhances The magnetic material or the ferrite-based material is suppressed from being attracted to the opening edge portion.

[0006]

However, JP-A-54-
No. 109040 has almost no effect on the soaring of powder containing a small amount of ferromagnetic raw material powder, and the one disclosed in JP-A-60-234794 cannot contain ferromagnetic raw material powder at all. Also, JP-A-60-234792
In No. No., the upper layer is a non-magnetic material only and the lower layer is a ferromagnetic material (or ferrite material) only, so it is annealed to reduce the stress of the tube skin during diameter reduction,
Alternatively, when a heat treatment for dehydrogenation is performed, the ferromagnetic material powder (iron powder, etc.) sinters into a lump, and as a result, a local thinning phenomenon occurs in the tube outer skin during the subsequent diameter reduction. Will cause a disconnection. As described above, all of the above-described conventional techniques have practical problems, and the problem of preventing the occurrence of skin cracks when the pipe diameter is reduced still remains. Once a skin crack occurs, even a minute crack initially extends in the longitudinal direction of the tube as the reduced diameter size of the tube becomes smaller, and becomes a length that cannot be ignored in the product size.

Therefore, according to the present invention, by obtaining a sound welded joint, it is possible to improve the product yield by eliminating the cracking of the outer cover when the pipe is reduced in diameter, and to fill the welding powder particles with good product quality. It is an object to provide a method for manufacturing a tube.

[0008]

According to the method for manufacturing a flux-cored wire for welding of the present invention, powder particles are supplied to a tubular body while forming a metal strip into a tubular body, and both edge surfaces of the tubular body are supplied. In a method for manufacturing a powder-filled tube, which is joined by high-frequency welding to reduce the diameter of a welded tube filled with powder, the powder is composed of a ferromagnetic raw material powder and a weak magnetic raw material powder in a predetermined mixing ratio. As a basic prescription, the above-mentioned basic prescription is used as a first type divided prescription granular material in which a ferromagnetic raw material powder and a weak magnetic raw material powder are mixed, and a second type divided prescription granular material in which a weak magnetic raw material powder is mixed. A plurality of divided prescription powders formed by dividing into at least two, and the first type divided prescription powders are provided on the lower layer side and the second type divided prescription powders are provided on the upper layer side and supplied to the tubular body. It is characterized by doing. Further, the mixing ratio of the weak magnetic raw material powders in the first type divided prescription powder and the second type divided prescription powders is set as the mixing ratio of the weak magnetic raw material powders in the basic prescription powder. .

Various raw material powders are selected for the powder or granular material supplied to the tubular body according to the purpose of use of the powder or granular material filling tube, and the powder is used as it is, that is, in the non-granulated state or in the granulated state. For example, in the flux used for the flux-cored wire for welding: -rutile sand, magnesia clinker, etc. as a slag generator-sodium silicate, potassium titanate, etc. as an arc stabilizer-deoxidizing agent-low C-Fe-as an alloying agent Si, Fe-Si
-Mn, Al-Mg, etc. weak magnetic raw material powders are blended as performance agents, and ferromagnetic raw material powders such as iron powder, iron oxide, etc. are adjusted for improving welding speed, adjusting flux filling rate, and welding workability. It is compounded as an agent. Welding performance agents, various raw material powders selected as regulators, and the compounding ratio in the flux are designed in advance according to the desired welding flux-cored wire, and in the present invention, this is the basic prescription powder (flux). Say.

Usually, all the raw material powders are contained in all the flux particles in the case of granulation, and all the raw material powders are mixed as a single powder in the case of non-granulation. Therefore, when granulating, ferromagnetic raw material powder such as iron powder, iron oxide, and iron alloy constitutes flux particles together with other weak magnetic raw material powder, and when non-granulating, iron powder, iron oxide, iron alloy, etc. The ferromagnetic raw material powder of is mixed as it is. That is, there is a sufficient risk of flux particles magnetically adhering to the opening edge surface which is magnetically poled at the time of high frequency welding in both cases of granulated and non-granulated flux. Due to the characteristics of the flux particles themselves, which are easily affected by the magnetic field as described above, various ideas have been developed so far (Japanese Patent Laid-Open Nos. 54-109040 and 54-90040).
Despite the proposals of 0-234794, JP-A-60-234792, etc.), practically satisfactory results have not yet been obtained.

According to the present invention, as shown in FIG. 1, a basic prescription flux F composed of such a ferromagnetic raw material powder and a weak magnetic raw material powder is used as a prescription flux containing a ferromagnetic raw material powder and a weak magnetic raw material powder. Divided into multiple groups of prescription flux consisting of F1 and weak magnetic raw material powder that does not contain ferromagnetic raw material powder (second type divided prescription) F2. Then, on the lower layer side in the tubular body 1, the first-class split prescription flux F
1 is supplied, and the second type divided prescription flux F2 is supplied to the upper layer side. This reduces the magnetic susceptibility of the flux located on the upper layer side, which is easily affected by the magnetic field, and suppresses the rising of the ferromagnetic raw material powder located on the lower layer side due to the magnetic field, by shielding the second-class split prescription flux F2 on the upper layer side. To do. Therefore, even when supplying a flux containing a relatively large amount of iron powder, which is a ferromagnetic component, to the tubular body,
Flux particles are not magnetically attached to the opening edge surface 2 of the tubular body 1 which is made into a magnetic pole during high frequency welding. Here, the ferromagnetic raw material powder means a raw material powder of a ferromagnetic material (iron powder, nickel powder, cobalt powder), and the weak magnetic raw material powder means a raw material powder (compound or alloy as a ferromagnetic component) other than the ferromagnetic material. (Including those containing).

Further, when the ferromagnetic raw material powder and the weak magnetic raw material powder are mixed in the lower layer side of the tubular body, that is, when the ferromagnetic raw material powder is dispersed and supplied, the tube filled with the flux is reduced in diameter while being reduced in diameter. Ferromagnetic materials (iron powder, etc.) even when stress relief annealing or dehydrogenation heat treatment of flux in pipe
It is possible to avoid the occurrence of wire breakage due to the phenomenon that the tubes do not sinter into a lump and the tube outer skin is locally thinned during the subsequent diameter reduction.

In the case where the powdered and granular material filling pipe is a flux-cored wire for welding, a weak magnetic raw material powder (slag forming agent, as a welding performance agent, not only on the upper layer side of the tubular body but also on the lower layer side thereof, is used.
Arc stabilizer, deoxidizer / alloying agent) are supplied so that the performance agent is spread throughout the pipe, and the ferromagnetic raw material powder (iron powder etc.) as a welding modifier is intensively supplied to the lower layer side.
When the flux-cored wire for welding manufactured in this manner is used for welding, the conductivity of the filling flux is improved, the flux protrusion length is shortened, and the welding speed is improved. obtain.

Next, a method of dividing the predesigned basic prescription flux to be filled into the pipe into the first type divided prescription flux and the second type divided prescription flux will be described. Basically, it is a basic prescription flux ... ferromagnetic raw material powder + weak magnetic raw material powder type 1 split prescription flux ... ferromagnetic raw material + weak magnetic raw material powder type 2 split prescription flux ... weak magnetic raw material powder, but weak Since a plurality of performance agents such as a slag generator, an arc stabilizer, and a deoxidizer / alloying agent are mixed as the magnetic raw material powder, the specific division mode of the weak magnetic raw material powder is further divided. That is, when the raw material powders for the basic prescription flux are ferromagnetic raw material powder ... X weak magnetic raw material powder ... Slag generator A, B arc stabilizer C deoxidizer / alloying agent E, F, as shown in Table 1. It is roughly classified into three division patterns.

[0015]

[Table 1]

Divided pattern 1 is an example in which all the weak magnetic raw material powders mixed in the basic prescription are mixed in the first and second types, and divided pattern 2 is all the performance agents that constitute the weak magnetic raw material powder in the basic prescription. An example in which the first type and the second type are blended, and the division pattern 3 is an example in which the performance agents that constitute the weak magnetic raw material powder of the basic formulation are different and blended in the first type and the second type. In any case, the total blending ratio of the raw material powders X, A, B, ... In the split prescription flux (first type, second type) coincides with the blending ratio of each raw material powder in the basic prescription flux. That is, the division ratio (wt%) of the basic prescription flux into the first type divided prescription flux and the second type divided prescription flux is as follows: first type: second type = n1: n2 (where n1 + n2 = 10)
0), and the raw material powder A of the basic prescription flux is divided.
When the (mixing ratio: Na (wt%)) is divided into the first type divided prescription and the second type divided prescription, the mixture ratio (wt%) of the raw powder A divided prescription fluxes type 1 and type 2 Respectively Na
When 1 and Na2 are given, the raw material powder A is divided and blended from the basic prescription to the divided prescription so that Na = Na1.n1 / 100 + Na2.n2 / 100.

In general, it is often desired that the raw material powders forming the granular material are dispersed and present in the entire tube in the granular material-filled tube as the functional material. Also in the flux-cored wire for welding, it is preferable for the welding workability that each raw material powder constituting the welding performance agent is dispersed in the entire pipe. In such a case, it is recommended to adopt the division pattern 1 among the above division patterns. As a desirable mode of this division pattern 1, the mixing ratio of the weak magnetic raw material powders in the first type divided prescription flux and the second type divided prescription flux is set to the mixing ratio of the weak magnetic raw material powders in the basic prescription flux. desired. That is, the mixing ratios of the weak magnetic raw material powders A, B, C, ... In the basic prescription flux are Na, Nb, Nc ,.
The compounding ratio in the first type split prescription flux is Na1, Nb
1, Nc1, ..., When the mixing ratios in the second type split prescription flux are Na2, Nb2, Nc2, ..., Na: Nb: Nc: ... = Na1: Nb1: Nc1: ... = Na2:
It is desirable to have an equal mixing ratio such as Nb2: Nc2 :. Each mixing ratio is represented by the following formula. (Type 1 split prescription flux) Mixing ratio of ferromagnetic raw material powder Nx1 = (Nx.100) / n1 (where Nx is the mixing ratio in the basic prescription flux of X) Mixing ratio of weak magnetic raw material powder A (B, C, ... as _{well) Na1 = f 1 (Na,} Nx, n1) = {Na · 100 · (n1-Nx)} / {n1 · (100-Nx)} ( second kind divided formulation flux) weakly magnetic material blending ratio of the powder a (B, C, ... _{similarly) Na1 = f 2 (Na,} Nx) = (Na · 100) / (100-Nx) table 2, the first type, second type dividing formulation flux 3 shows the mixing ratio of the ferromagnetic raw material powder and the weak magnetic raw material powder in FIG. FIG. 2 is a diagrammatic representation of this relationship.

[0018]

[Table 2]

[0019]

In the present invention, the basic prescription composed of the ferromagnetic raw material powder and the weak magnetic raw material powder is the powder material (the first type divided prescription) in which the ferromagnetic raw material powder and the weak magnetic raw material powder are mixed, and the ferromagnetic raw material. It is divided into a plurality of groups of powder particles (second type divided prescription) consisting only of weak magnetic raw material powder that does not contain powder. Then, the first-type divided prescription granular material is supplied to the lower layer side of the tubular body, and the second-type divided prescription granular material is supplied to the upper layer side. As a result, the magnetic susceptibility of the granular material located on the upper layer side, which is easily affected by the magnetic field, can be reduced, and the rising of the ferromagnetic raw material powder located on the lower layer side due to the magnetic field is suppressed in the second-class split prescription granular material on the upper layer side. It can be suppressed by shielding. Therefore, even when supplying a granular material containing iron powder, which is a ferromagnetic component, into the tubular body, the granular particle does not magnetically adhere to the edge surface of the tubular body that is magnetically poled during high frequency welding. Therefore, the cracking of the tube caused by the magnetic particles in the granular material being magnetically attached to the edge surface of the tubular body is substantially eliminated. In addition, since the ferromagnetic raw material powder and the weak magnetic raw material powder are mixed in the lower layer side of the tubular body, that is, the ferromagnetic raw material powder is dispersed and supplied, the tube filled with the powder or granular material is reduced in diameter while being reduced. Even when stress-relieving annealing of the outer shell or dehydrogenation heat treatment of powder particles in the tube is performed, the ferromagnetic materials (iron powder, etc.) do not sinter and become agglomerates. It is possible to avoid the occurrence of disconnection due to a local thinning phenomenon.

[0020]

EXAMPLES The manufacturing of flux-cored wires for welding will be described below as examples. FIG. 3 is a configuration diagram of a main part of the welding flux-cored wire manufacturing apparatus. As shown in FIG. 3, the forming roll group 3, the side rolls 5, and the flux supply device 4 are arranged along the feed direction of the open pipe (tubular body) 1.
1, 42 are arranged. A preforming roll (not shown) is provided on the upstream side of the forming roll 3. In the open tube 1 in the middle of molding, first, the flux supply device 4
The first type divided prescription flux F1 forming the lower layer is supplied from No. 1, and subsequently the second type divided prescription flux F2 forming the upper layer is supplied from the flux supply device 42. Open tube 1 supplied with flux F1 and F2
Passes through the fin pass roll 6 and the seam guide roll 7 and enters the welding zone. FIG. 4 is a sectional view taken along the line IV-IV in FIG. 3 immediately after supplying the second type split prescription flux F2, and FIG.
FIG. 3 is a sectional view taken along the line V-V in the welding zone. As shown in the figure, the layer 2 is supplied in a layered manner so that the upper layer side second-class divided prescription flux F2 covers the lower layer side first-type divided prescription flux F1. To be done. 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 12. The welded pipe 11 has an extra bead 14 on the outer surface side cut by a cutting tool 13 (the inner bead 16 remains in the pipe), is rolled by a group of rolling rolls 15, and is further annealed by a rolling device and a wire drawing device. (Neither is shown) The diameter is reduced to a product size of about 1.0 to 2.0 mm.

By such high frequency induction welding, the width w = 3
A steel strip with a diameter of 0 to 150 mm and a thickness t of 1 to 5 mm is
= Make a pipe with a diameter of 10 to 50 mm. As welding conditions at this time, frequency of high frequency current f = 300 to 800
kHz Heat input (EpIp) P = 50-500kV
A Distance between work coil and welding point L = 10 to 100 mm Apex angle (V convergence angle) θ = 3 to 15 ° is adopted, welding speed (pipe forming speed) V = 10
Pipe forming is performed at a speed of about 200 m / min.

In such high-frequency welding, since a magnetic field is generated in the tubular body by supplying a high-frequency welding current and the opening edge becomes a magnetic pole, the magnetic particles existing in the flux surface layer soar and magnetically adhere to the opening edge. Easier to do. In the present invention, the first-class split prescription flux in which the ferromagnetic raw material powder such as the iron powder is blended together with the weak magnetic raw material powder such as the rutile is supplied to the lower layer side, and then the second weak magnetic raw material powder is blended.
By supplying the seed division prescription flux to the upper layer side,
The 1st-class divided prescription flux that floats up to the opening edge portion by the magnetic attraction force as it is is suppressed by the shielding action of the 1st-class divided prescription flux that is not affected by the attractive force (FIGS. 4 and 5).

Next, the result of cracking of the flux-cored wire for welding manufactured by the above apparatus will be described.

Steel strip 2.5 mm thick and 75.0 mm wide (SP
HC, C = 0.05%), outer diameter 25.5 mm, inner diameter 2
Molded into 0.5 mm tubes. Flux was filled at a filling rate of 10 to 20% during molding, and open pipes were continuously butt-joined. At this time, the frequency of the high frequency current supplied to the work coil is 500 kHz, and the heat input (EpIp) P = 160 kV
A, welding speed V was 35 m / min, work coil to welding point distance was 30 mm, and apex angle was 7 °. Welded pipe with an outer diameter of 25.5 mm is subjected to continuous annealing once with a rolling roll group once to reduce the outer diameter to 4.0 mm, and heat treatment and plating for annealing the outer shell of the pipe and dehydrogenation of the filling flux. It was processed and wound into a coil. Next, finish wire drawing with a hole die or roller die, and the outer diameter of the pipe is 1.2 mm.
The diameter of the product wire was reduced to a product size of up to 1.6 mm and the occurrence of cracks in the product wire was examined.

Table 3 shows the raw material powder (ferromagnetic raw material powder (iron powder) + weak magnetic raw material powder) of the basic prescription flux used and its mixing ratio. The four types of basic prescriptions shown in Table 3 were divided according to the division pattern shown in Table 1, and the first type (ferromagnetic raw material powder (iron powder) + weak magnetic raw material powder) and the second type (weak magnetic raw material powder) shown in Table 4 were divided. )
The split prescription flux was prepared. The divided prescription flux was prepared by mixing the raw material powders of the respective basic prescriptions shown in Table 1 and granulating, or in the non-granulated state as it was mixed. The particle size of each raw material powder is 250 μm or less, and the particle size of the granulation flux is 15
It was less than 00 μm.

[0026]

[Table 3]

[0027]

[Table 4]

[0028]

[Table 5]

The evaluation of cracks was made by drawing an outer diameter of 1.2 to 1.6.
mmφ product wire 100km (20kg wire spool ×
37) Eddy current flaw detection test (E)
CT) was performed to confirm the presence and position of cracks, and when a crack signal was output, the relevant portion was observed with a magnifying glass to confirm the presence of cracks in the wire longitudinal direction. When the presence of cracks could not be confirmed at all, this was evaluated as good (◯).
Also, if there is a crack, the treatment liquid tends to infiltrate into the wire during surface treatment or wire drawing from the opening of the crack and deteriorate the quality of the product. This was regarded as a defect (x).

In Table 4, Experiment Nos. 1 to 9 are experimental examples of the present invention. Experiment No. 1 ... The basic formulation F-1 was divided into the first and second types by the division pattern 1 (weak magnetic raw material powder: equal mixing ratio ... corresponding to claim 2). First type: Second type = 50 A flux (first type: granulation, second type: granulation) divided by 50 was used. The first type was supplied to the lower layer side and the second type was supplied to the upper layer side at a flux filling rate of 12%. Experiment No. 2 ... Dividing basic formulation F-1 into 1st type and 2nd type by division pattern 1 (weak magnetic raw material powder: unequal mixture ratio) 1st type: 2nd type = 40:60 Was used (first type: non-granulated, second type: non-granulated). 1
The seeds were supplied to the lower layer side and the second species to the upper layer side at a flux filling rate of 11%. Experiment No. 3 ... Dividing the basic formulation F-2 into 1st type and 2nd type by dividing pattern 1 (weak magnetic raw material powder: equal mixing ratio ... Corresponding to claim 2) 1st type: 2nd type = 60 The flux (first type: granulation, second type: granulation) divided by 40 was used. The first type was supplied to the lower layer side and the second type was supplied to the upper layer side at a flux filling rate of 15%. Experiment No. 4 ... The basic prescription F-2 was divided into two patterns,
Ratio of division into 1st type and 2nd type 1st type: 2nd type = 50: 5
A flux divided by 0 (first type: granulated, second type: non-granulated) was used. The first type was supplied to the lower layer side and the second type was supplied to the upper layer side at a flux filling rate of 15%. Experiment No. 5: Dividing ratio of basic formulation F-3 into 1st type and 2nd type by dividing pattern 1 (weak magnetic raw material powder: equal mixing ratio ... Corresponding to claim 2) 1st type: 2nd type = 40 The flux (first type: granulation, second type: granulation) divided by 60 was used. The first type was supplied to the lower layer side and the second type was supplied to the upper layer side at a flux filling rate of 17%. Experiment No. 6 ... The basic prescription F-3 was divided into patterns 3
Ratio of division into 1st type and 2nd type 1st type: 2nd type = 50: 5
The flux divided by 0 (first type: granulation, second type: granulation) was used. The first type was supplied to the lower layer side and the second type was supplied to the upper layer side at a flux filling rate of 17%. Experiment No. 7: Dividing ratio of basic formulation F-4 into 1st type and 2nd type by dividing pattern 1 (weak magnetic raw material powder: equal mixing ratio ... Corresponding to claim 2) 1st type: 2nd type = 50 A flux (first type: granulation, second type: granulation) divided by 50 was used. The first type was supplied to the lower layer side and the second type was supplied to the upper layer side at a flux filling rate of 20%. Experiment No. 8: The basic formulation F-4 was divided into the first type and the second type by the division pattern 1 (weakly magnetic raw material powder: equal mixing ratio ... corresponding to claim 2). First type: Second type = 60 : The first type is divided into 40 parts, and the first type is divided into different amounts of iron powder (iron powder amount: for lower layer upper layer <for lower layer lower layer) for lower layer upper layer and lower layer side lower layer: For lower layer upper layer: Lower layer side Lower layer = 1: 1 divided flux (1st type: granulated, 2nd type: non-granulated)
It was used. The first type was supplied to the lower layer side and the second type was supplied to the upper layer side at a flux filling rate of 20%. As in this example, the first-class split prescription flux supplied to the lower layer side is further divided to mix more iron powder in the flux located in the lower layer. It is effective when applied when mixed. Experiment No. 9: Dividing ratio of basic formulation F-2 into 1st type and 2nd type by dividing pattern 1 (weak magnetic raw material powder: equal mixing ratio ... Corresponding to claim 2) 1st type: 2nd type = 40 : 60, and the second type is divided into upper and lower layers.
For upper layer: for lower layer side For lower layer = 2: 1 divided flux (first type: granulation, second type: granulation) was used. The first type was supplied as an upper layer on the lower layer side and the second type was supplied as an upper layer side and a lower layer on the lower layer side at a flux filling rate of 17%. As in this example, the treatment of further dividing the second type split prescription flux and arranging it in the lowermost layer is more effective in dispersing each raw material powder as a welding performance agent that constitutes the basic prescription flux throughout the pipe. The effect can be expected.

In these experimental examples, the second-class split prescription flux (weak magnetic raw material powder) supplied to the upper layer side is the first-type split prescription flux (ferromagnetic raw material powder (iron powder) + weak magnetic) supplied to the lower layer side. The raw material powder) is shielded, and the weight pressure of the upper layer suppresses it. Therefore, the first-class split prescription flux particles on the lower layer side did not soar up due to the magnetic field generated in the tube and magnetically adhered to the edge surface of the tube, and cracking of the tube skin due to this magnetic adhesion did not occur. Further, the iron powder X is replaced by the weak magnetic raw material powders A, B,
Since the iron powder was mixed with C, D, E, F, and G and supplied in a dispersed state, the iron powder did not sinter due to the heat treatment, and the disconnection due to the sintering did not occur.
When welding was performed using this flux-cored wire for welding, good welding workability was realized.

On the other hand, Experiment Nos. 10 to 13 are comparative examples, and the basic prescription flux (ferromagnetic raw material powder (iron powder) + weak magnetic raw material powder) F-1, F-2, F-3, respectively. , F
-4 was packed in one layer. In these experimental examples, since magnetic particles (iron powder or granulated particles containing iron powder) are present in the flux surface layer portion facing the tube edge, the magnetic particles directly affect the influence of the magnetic field generated in the tube. As a result, the edge of the pipe was magnetically adhered and magnetically adhered to the pipe, and as a result, cracks were generated in the pipe skin, reducing the product yield.

Although not shown, in addition to these experimental examples, a basic prescription flux (ferromagnetic raw material powder (iron powder) + weak magnetic raw material powder) F-1 (iron powder mixing ratio: 10%) was used as a ferromagnetic raw material powder ( Iron powder) and weak magnetic raw material powder are separated into two types of flux, and ferromagnetic raw material powder (iron powder) is the lower layer, and ferromagnetic raw material powders A, B, C, D, E, F and G are the upper layers. A comparative example was also experimented to be supplied so that In this experimental example, the upper ferromagnetic raw material powder layer suppresses the lower iron powder layer by its weight pressure,
No cracking of the tube skin due to magnetic particles magnetically attached to the tube edge surface occurred. However, since iron powder is separately supplied to the lower layer, the iron powder sinters into a lump by heat treatment, and when the diameter of the pipe is reduced thereafter (especially during finish wire drawing).
Frequent wire breakages caused a drop in product yield.

[0034]

According to the present invention, a basic prescription composed of a ferromagnetic raw material powder and a weak magnetic raw material powder is blended with a ferromagnetic raw material powder and a weak magnetic raw material powder to form a divided prescription powder (type 1 division). Prescription) and divided prescription powders consisting of only weak magnetic raw material powders that do not contain ferromagnetic raw material powders (second type divisional prescription) are divided into multiple groups, and the first type divided prescription powders are placed on the lower side of the tubular body. Supply, and the second-class divided prescription powder and granules are supplied to the upper layer side,
The magnetic susceptibility of the granular material located on the upper layer side, which is easily affected by the magnetic field, is reduced, and the rising of the ferromagnetic raw material powder located on the lower layer side due to the magnetic field is prevented by the shielding of the second-class split prescription granular material on the upper layer side. It can be suppressed by the weight pressure. Therefore, even when supplying a granular material containing iron powder, which is a ferromagnetic component, to the tubular body, the granular particle is not magnetically attached to the edge surface of the tubular body that is magnetically poled during high frequency welding, and the magnetic particle is Cracks in the tube due to magnetic attachment to the surface are substantially eliminated. In addition, since the ferromagnetic raw material powder and the weak magnetic raw material powder are mixed in the lower layer side of the tubular body, that is, the ferromagnetic raw material powder is dispersed and supplied, the tube filled with the powder or granular material is reduced in diameter while being reduced. Even when stress-relieving annealing of the outer skin or dehydrogenation heat treatment of powder particles in the tube is performed, the ferromagnetic materials (iron powder, etc.) do not sinter and become agglomerates. It is possible to avoid the occurrence of disconnection due to the local thinning phenomenon occurring on the tube skin.

When the powder-filled tube is a flux-cored wire for welding, a weak magnetic raw material powder (slag-forming agent, as a welding performance agent, not only on the upper layer side of the tubular body but also on the lower layer side thereof, is used.
Arc stabilizer, deoxidizer / alloying agent) are supplied so that the performance agent is spread throughout the pipe, and the ferromagnetic raw material powder (iron powder etc.) as a welding modifier is intensively supplied to the lower layer side.
When the flux-cored wire for welding manufactured in this manner is used for welding, the conductivity of the filling flux is improved, the flux protrusion length is shortened, and the welding speed is improved. obtain.

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 is an explanatory diagram showing a relationship between a basic prescription flux and a first type and a second type divided prescription flux.

FIG. 2 is an explanatory diagram of a case where weak magnetic raw material powders are divided at equal mixing ratios.

FIG. 3 shows an example of an apparatus for manufacturing the powder / particle filling tube of the present invention, and is a configuration diagram of a main part of a welding flux-cored wire manufacturing apparatus.

FIG. 4 is a sectional view taken along the line IV-IV of FIG. 3, showing a sectional view of the tubular body at a flux supply position.

5 is a sectional view taken along line VV of FIG. 3, showing a sectional view of the tubular body at a work coil position.

[Explanation of symbols]

 1 Open Pipe (Tubular Body) 2 Open Edge Surface 3 Forming Roll Group 41 Flux Supply Device (For Lower Layer) 42 Flux Supply Device (For Upper Layer) 5 Side Roll 6 Fin Pass Roll 7 Seam Guide Roll 8 High Frequency Welding Device 9 Work Coil 10 Squeeze roll 11 Welded tube 12 Power supply 15 Rolling roll group F Basic prescription flux F1 Type 1 split prescription flux F2 Type 2 split prescription flux

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Haruji Hashimoto 3-5-4 Tsukiji, Chuo-ku, Tokyo Inside Nittetsu Welding Industry Co., Ltd.

Claims (2)

[Claims] 1. A powdery or granular material is supplied to the tubular body in the course of forming a metal strip into a tubular body, both edge surfaces of the tubular body are joined by high frequency welding, and a welded tube filled with the granular material is compressed. In the method for producing a powder-filled tube having a diameter, the powder is a basic raw material composed of a ferromagnetic raw material powder and a weak magnetic raw material powder at a predetermined mixing ratio, and the basic prescription is a ferromagnetic raw material powder. And a plurality of divided prescription granules composed by dividing at least two into a first type divided prescription granule containing the weak magnetic raw material powder and a second type divided prescription granule containing the weak magnetic raw material powder. And supplying the first type divided prescription granular material to the lower layer side and the second type divided prescription granular material to the upper layer side to the tubular body. 2. The compounding ratio of the weak magnetic raw material powders in the first type divided prescription powder and the second type divided prescription powders is defined as the mixing ratio of the weak magnetic raw material powders in the basic prescription powder. Item 1. A method for manufacturing a powder-filled tube according to item 1.