JPH09314375A - Welding wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding wire excellent in the wire feedability to a conduit tube, etc., and capable of being prevented from biting into a spool, etc. SOLUTION: A welding wire is 0.001 to 0.05 in the specific area of the wire to be expressed by the formula ((Sa /Sm )-1) where, Sa (mm<2> ) is the area of a wire solid surface 2 in a region to be measured, Sm (mm<2> ) is the area of an apparent surface 3. The natural electric potential after the wire surface is degreased, and the wire is immersed in the sodium chloride solution of 0.1mol/liter at 30 deg.C for 300 seconds is -600 to -400mV with reference to the saturated calomel electrode. Since the specific surface area and the natural electric potential are of the above-mentioned values, the raggedness of the wire surface and the thickness of the oxide film are appropriate. Since the friction force of the wire surface is increased, biting in the arc start is prevented, and the wire feedability becomes excellent since the friction force is constant regardlessly of the position.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a non-plated welding wire, and in particular, a welding wire suitable as flux-cored wire and solid wire for gas shielded arc welding, solid wire for submerged arc welding, etc. About.

[0002]

2. Description of the Related Art Conventionally, it has been practiced to secure the feedability of a welding wire by applying a feeding lubricant to the surface of the welding wire to suppress the frictional force as much as possible. There is. Such a welding wire is wound on a spool or neatly stored in a pack, and pulled out from the spool or pack at the time of welding and used.

FIG. 6 is a cross-sectional view showing a spool. As shown in FIG. 6, the spool is composed of a spool support 51 and a spool main body 52. A bottom plate 53 is disposed below the spool support 51, and the bottom plate 5
A standing plate 54 is set up at 3. A shaft 55 is connected horizontally to the central portion of the standing plate 54. On the other hand, the spool body 52 is composed of a bearing portion 60 and side plates 59 provided at both ends of the bearing portion 60, and the through hole 58 is provided in the bearing portion 60. A welding wire 56 is wound around the outer periphery of the bearing portion 60 inside the side plate 59. The aforementioned shaft 55 is inserted into the through hole 58
Is inserted, and the spool body 5 with the shaft 55 as a support shaft
2 is rotatable. The hatched portion 57 in the figure indicates a welding wire wound around the spool main body 52.

In such a spool, when the welding wire 56 is pulled to be fed to a welding torch (not shown), the spool body 52 rotates in the advancing direction of the wire 56. Thus, the welding wire 56 is used as the welding torch.
Is supplied.

[0005]

However, the above-mentioned prior art has the following problems. That is, the shaft 55
The surface condition of the shaft 55 or the shaft 55 and the through hole 58
If there is insufficient clearance between the
There is a problem that the rotation of the spool main body 52 is not smooth and a jamming occurs at the time of arc start.

FIG. 7 is a cross-sectional view showing the spool shown in FIG. 6 in an enlarged manner, and shows a state in which penetration occurs. In FIG. 7, the same components as those in FIG. 6 are designated by the same reference numerals and their detailed description will be omitted. As shown in FIG. 7 (a),
The welding wire 56 is neatly wound around the spool body 52. For example, portions 56e to 56i of the welding wire are aligned along the bearing portion 60 of the spool body 52, and portions 56a to 56d of the welding wire are provided on the outside of the portion 56e to 56i of the welding wire. Side by side. For this reason, when the spool body 52 rotates and the welding wire is fed, the portions 56a to 5 of the welding wire
6i is sequentially released from the spool main body 52 in ascending order of the alphabet of the code. In this case, the outer welding wire is disposed so as to be positioned between the inner welding wires, for example, the welding wire portion 56a is disposed between the welding wire portions 56g and 56h. ing.

In the spool thus constructed,
The welding wire is pulled in a direction perpendicular to the bearing 60 and fed to start welding. As a result, although there is no particular problem if the rotation of the spool body 52 is smooth, if the rotation is not smooth, as shown in FIG. 7B, the portion 56a of the welding wire is the radius of the spool body 52 The force to sink in the direction acts, and the wire portion 56a gets in between the wire portions 56g and 56h.

Also, as shown in FIG. 8 (a), the portions 56k to 56p of the welding wire are aligned along the bearing portion 60, and the portion 56j of the wire is outside the portions of these wires. The wire portion 56 j may be in contact with the wire portion 56 k and the side plate 59. In this case, when the part 56j of the wire is loosened from the spool main body 52, the part 56j of the wire sinks, and as shown in FIG. 8 (b), the part 56k of the wire And the side plate 59.

Thus, part 56a or 56 of the wire
If j gets into a part of the lower wire, it will be difficult to feed the welding wire and the arc will stop. In particular, the penetration shown in FIG. 8 (b) frequently occurred and became a problem.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a welding wire which is excellent in wire feeding property to a conduit tube etc. and in which the penetration of the wire into a spool etc. is prevented. With the goal.

[0011]

SUMMARY OF THE INVENTION The welding wire according to the present invention is characterized in that the actual surface area of the wire in the area to be measured is S _a (m
m ² ), the apparent area in the measurement target area is S _m
When it is set as (mm ² ), the wire specific surface area represented by the equation ((S _a / S _m ) -1) is 0.0001 to 0.0
5. After degreasing the wire surface, the natural potential after immersion for 300 seconds in 0.1 mol / liter sodium chloride solution at 30 ° C. is -600 to -400 mV based on the saturated sweet potato electrode. It is characterized by

In this case, the surface of the welding wire is MoS.
₂ which is preferably ² deposited or applied 0.002 to 0.60 g / m.

Also, the surface has an electrical resistance of 10 ^{-4 to} 1.
0.002 to 0.60 g of lubricant that is 0 ^{+ 4} Ω · cm
/ M ² may be adhered or applied.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION As a result of repeating various experimental studies to achieve the above object, the inventors of the present invention have achieved the frictional force of the wire by forming an oxide film of the appropriate thickness on the surface of the wire. It has been found that the height is increased, and the penetration of the wire is prevented (the feedability at the time of intermittent welding is improved).
However, when the wire passes through the conduit tube, the frictional force between the conduit tube and the wire may differ depending on the portion of the wire, which may deteriorate the feedability during continuous welding. In order to solve this, as a result of various investigations, it was found that the frictional force of the wire becomes constant and the wire passes smoothly through the conduit tube by forming a concavo-convex shape of appropriate roughness on the wire surface. .
Thus, it is possible to obtain a welding wire in which penetration is prevented while maintaining good feedability during continuous welding (good feedability during intermittent welding).

Hereinafter, the present invention will be described in more detail. In the prior art, attempts have been made to improve the feedability by applying a lubricant to the surface of the welding wire to suppress the frictional force on the surface of the wire, but with this method, the wire feeding failure is eliminated. It is difficult to do, and the penetration may be noticeable. Therefore, as a result of intensive investigations by the inventors of the present application, not only suppression of the frictional force on the surface of the wire but also increase in the frictional force and suppression of variations in the frictional force at each portion of the surface of the wire prevent pissing. I clarified what I could do. That is, if, in FIG. 7, the frictional force between the portion 56a of the welding wire and the portions 56g and 56h of the wire is greater than the force with which the portion 56a of the wire tries to sink radially, I came to think that it can prevent the penetration. In order to increase the frictional force on the surface of the wire, it is sufficient to form an uneven shape on the surface of the wire. Such an uneven shape can be formed, for example, by polishing the surface of the wire. In addition, when the wire is washed with an acidic solution, the above-described uneven shape is also formed by setting the washing condition to be appropriate, or performing the surface reduction process on the wire with an appropriate reduction ratio after the washing. Can.

However, in order to prevent the penetration of the wire by increasing the friction force of the welding wire,
It is necessary to solve the following two problems.

First, when the frictional force on the surface of the wire becomes large, the frictional force between the conduit tube and the surface of the wire in the tube becomes large, and the wire feeding performance is deteriorated. Therefore, it is necessary to prevent this deterioration. As a result of numerous trial and error, it was found to control the surface of the wire physically and chemically. That is, in addition to controlling the concavo-convex shape of the wire surface within a certain range (physical control), forming an extremely thin oxide film containing iron oxide as the main component on the wire surface (chemical control) It was found that the wire feedability was good for both the start and continuous welding.

The effects of the irregularities on the wire surface and the thin iron oxide film formed on the wire surface will be further described. Initially, no oxide film is formed on the wire surface,
An attempt was made to increase the surface friction between the wires in a spool or the like by controlling the surface roughness of the wires to be large (rough). However, with this method, the variation in friction force becomes large, and it has been difficult to feed the wire stably during continuous welding. Therefore, in order to suppress the variation in wire feeding resistance while increasing the frictional force, various experimental studies were conducted. As a result, it has been found that, by forming an extremely thin film containing iron oxide as a main component on the surface of the wire, it is possible to suppress the variation in the feeding resistance of the wire.

Although the details of the mechanism by which the oxide film suppresses the variation in the wire feeding resistance are unknown, it can be considered as follows. That is, when the feed resistance is measured, it is considered that the cause of the variation in the feed resistance value at each portion of the wire is due to the convex shape of the wire surface. It is considered that variation in the feed resistance value occurs when this convex shape comes in contact with the inner surface of the wire feed system, particularly the conduit tube or the like. When an oxide film is formed on the convex portion of the wire surface, the oxide film comes into contact with the inner surface of the conduit tube or the like instead of the convex shape, so the frictional force between the wire surface and the inner surface of the conduit tube is reduced. It is guessed that.

As compared with the welding wire of the present invention, in the case of a wire having a smaller uneven shape on the surface of the wire, since the surface friction force is smaller as described above, the phenomenon of penetration during arc start frequently occurs. When an oxide film mainly composed of iron oxide is formed on such a smooth wire, although the average value of the wire feeding resistance value increases, no variation occurs in the resistance value. The phenomenon is gone. However, such a wire had poor wire drawability at the time of wire production.

The next problem relates to a method of evaluating the thickness of the oxide film of the thin film formed on the surface of the welding wire. That is, although the film thickness evaluation method is not directly related to the wire feedability of the welding wire, if the film thickness can not be accurately evaluated, it is confirmed whether or not an oxide film of an appropriate film thickness is formed. It is difficult to obtain a welding wire having a predetermined film thickness.

Initially, the inventors of the present application have described Auger Electron Spectroscopy, X-ray Photoelectron Spectroscopy, Electron Spect, and the like.
The difference between the chemical composition of the oxide film and the chemical composition of the welding wire is detected by roscopy for Chemical Analysis (ESCA) and fluorescent X-ray analysis, and the film thickness of the oxide film is measured. In any of the methods, it was difficult to quantitatively measure the thickness of the oxide film over a wide range.

Therefore, after the wire surface is washed with an organic solvent to remove deposits and degreased, the obtained wire is immersed in a sodium chloride solution, and the natural potential of the wire is measured to determine the natural potential. The evaluation method to evaluate the thickness of the oxide film was found. In this method, for example, a 0.1 mol / liter sodium chloride solution having a temperature of 30 ° C. is prepared, the surface of the sodium chloride solution is released to the atmosphere, Ar gas is blown to remove the dissolved oxygen, and the solution is cleaned. Soak the wires after. After 300 seconds, the natural potential of the wire is measured on the basis of the saturated sweet potato electrode.
In this case, it is usually possible to immerse the wire in a solution of several 10 mm sodium chloride, so it is possible to evaluate the average oxide film thickness in the longitudinal and circumferential direction of the wire.

The present invention is obtained by solving the above two problems, but when using a welding wire in a severe wire feeding system or the like, stable wire feeding can be achieved. In order to further secure the property, it is preferable to apply a solid lubricant such as MoS _{2 to} the surface of the welding wire. Thereby, the average value of the wire feeding resistance can be further reduced. Solid lubricants other than MoS ₂ include carbon based lubricants and W, Ta, Ti, Zr, Nb
And / or a compound lubricant comprising a high melting point metal element such as Mo and an oxygen group element such as O, S, Se and / or Te. The specific electrical resistance of any of the lubricants is more preferably equal to or less than that of MoS _2, and more specifically, about 10 ^{−4 to} 10 ⁺⁴ Ω · cm.

Further, in order to obtain a more stable wire feeding property, a conventionally used oil type lubricant may be applied to the welding wire for the purpose of rust prevention of the wire surface.

In the present invention, it is assumed that the actual surface area of the wire surface measured three-dimensionally is S _a and the apparent area of the wire surface is S _m and the wire specific surface area is ((S _a /
Expressed as (S _m ) -1), the surface roughness in the longitudinal direction and circumferential direction of the wire is simultaneously evaluated by this specific surface area.
The specific surface area can be calculated by the following method.

FIG. 1 is a schematic view showing a real surface in a minute area of the wire surface by a three-dimensional orthogonal coordinate system, and FIG. 2 is a schematic view showing a measurement area of the specific surface area of the wire surface.
As shown in FIG. 1, the actual surface 2 of the wire surface has irregularities, and the area S _a of the actual surface 2 is X-Y of the actual surface 2.
It is larger than the area S _{m of} the apparent surface 3 projected onto the surface. Therefore, as shown in FIG. 2, the length of the wire in the longitudinal direction (lateral direction) is 600 μm on the surface of the wire 1,
A measurement area (measurement field of view) having a length of 500 μm in the circumferential direction (longitudinal direction) was taken and developed in a plane.

FIG. 3 is a schematic view showing a mesh for dividing the measurement area in order to calculate the actual surface area. As shown in FIG. 3, the developed plane is divided into 256 horizontally and 2 vertically
Divide into 00 and divide into 256 × 200 finite intervals. Next, the position of the real surface at the intersection of each mesh, that is, the height of the real surface is measured. In the three-dimensional orthogonal coordinate system of FIG. 1, the XY plane is the measurement field of view, and the height of the real surface corresponds to the value of the Z axis.

FIG. 4 is a schematic diagram showing the height position of the real surface at each intersection of meshes by a three-dimensional orthogonal coordinate system, and approximating the real surface with connected triangles, and FIG. 5 shows the area of the triangle in FIG. It is a schematic diagram which shows the method of calculating. As shown in FIG. 4, the positions of the heights H ₁₁ , H ₁₂ and H ₂₁ etc. of the real surface are connected every three points, and the real surface is approximated by a series of many triangles obtained. Next, as shown in FIG. 5, and calculates an area S ₁₁ and S ₁₂ and the like of each of these triangles, by summing the areas of all the triangles, calculates the actual surface S _a.

The heights H ₁₁ and H _{12 and the} like of the actual surface at the mesh intersections in this measurement field of view can be measured by an electron beam three-dimensional roughness analyzer. This three-dimensional roughness analyzer is a type of SEM (scanning electron microscope), which irradiates an electron beam in a direction substantially perpendicular to the sample surface and aligns secondary electrons in four equal directions from the electron beam irradiation point. Is detected by four detectors. Then, by processing the obtained result with a microcomputer, three-dimensional (X,
The position information of Y, Z) can be obtained.

The apparent surface area S _m is the area of the measurement area (measurement field of view), ie, S _m = 500 (μm) × 6.
It becomes 00 (μm) = 300000 (μm ² ). Thus, from the apparent surface area S _m and the actual surface area S _a in consideration of the unevenness of the actual surface, the wire specific surface area ((S _a /
S _m ) -1) can be calculated. In addition, the sample for calculating a wire specific surface area is extract | collected as follows.

First, as much as possible without putting wrinkles,
A portion of about 20 mm is taken from any three places along the longitudinal direction of the welding wire and used as a sample. Next, the sample obtained is petroleum ether, which does not corrode metal surfaces.
Ultrasonic cleaning is performed in an organic solvent such as acetone, carbon tetrachloride or chlorofluorocarbon to remove impurities such as dirt and fats and oils adhering to the surface of the wire (sample). It should be noted that depending on the type of lubricating oil used in the process of processing welding wire instead of the aforementioned organic solvent, a liquid such as oil or other degreasing fluid that seems to be most suitable for excluding this lubricating oil Prepare
Ultrasonic cleaning may be performed in this liquid. In any case, the ultrasonic cleaning is performed one by one so that the samples do not rub against each other and wrinkles are generated.

In this case, in the manufacture of the wire, it is to be noted that, as far as possible, wrinkles and abrasions generated by contact between the die by wire drawing, contact between various parts of the equipment and lines, are not generated as much as possible. Therefore, when actually calculating the actual surface area, it is preferable to select a portion having no wrinkles on the surface of the sample as much as possible and use this portion as a measurement region. In addition, this specific surface area is measured at three locations where one arbitrary cross section of one sample is shifted by 120 degrees, and is taken as a simple average of the measured values at a total of nine locations of three samples. The magnification is 150 times.

The measured value of the actual surface can be made closer to the true value by dividing the mesh shown in FIG. 5 into smaller pieces. However, when the number of divisions of the mesh is increased, the improvement of the wire evaluation accuracy is extremely small, although the problem that the analysis by the computer takes a long time and the like occurs. Therefore, the measurement area of 500 μm × 600 μm
The specific surface area may be calculated by dividing it into 00 × 256 sections, and the obtained specific surface area has sufficient accuracy to evaluate the evaluation roughness of the wire.

The reasons for the numerical limitation of the welding wire in the present invention will be described below.

Specific surface area: 0.0001 to 0.05 If the specific surface area of the welding wire is less than 0.0001, an oxide film is formed on the surface of the wire, so no penetration at the arc start occurs, but the surface Is extremely smooth, and during wire drawing, nori of the wire-drawing lubricant is deteriorated, and the wire-drawing becomes difficult. As a result, the die life becomes extremely short. On the other hand, when the specific surface area of the wire exceeds 0.05, it is difficult to suppress the variation in the feeding resistance even if an oxide film is formed on the surface of the wire, and the feeding of the wire is not constant. The arc length fluctuates, and it is necessary for the worker to always adjust it, resulting in increased worker fatigue. Therefore, the specific surface area of the welding wire measured after oxide film formation is set to 0.0001 to 0.05.

In order to further improve the processability at the time of wire production (die life extension), wire feedability and arc stability at the time of welding, the specific surface area of the wire is 0.
It is preferable to set it as 001 to 0.035.

Self potential (thickness of oxide film): -600
If the natural potential of the wire for welding to -400mV is less than -600mV , the thickness of the oxide film is small, so that the effect of suppressing the variation in the feeding resistance is insufficient. On the other hand, when the natural potential exceeds -400 mV, penetration at the arc start is likely to occur, and wire feedability is reduced. Also, the baked wire according to the prior art has a natural potential of -400 mV
And the power supply from the feed tip to the wire tends to be unstable, and the wire feedability is lowered.
It becomes easy to occur. Therefore, the natural potential is -6
It is set to 00 to -400 mV.

The above-mentioned natural potential is obtained by washing and degreasing the wire surface with an organic solvent, and then preparing a 0.1 mol / liter sodium chloride solution at a temperature of 30 ° C. The wire after cleaning is immersed in the solution while releasing Ar and blowing Ar, and after 300 seconds, it shall be measured based on the saturated sweet potato electrode.

Incidentally, the surface natural potential of the prior art bright finish welding wire is about -700 mV although it depends on the chemical composition of the wire.

Adhesion or application amount of MoS ₂ : preferably
0.002 to 0.60 g / m ² As described above, the surface of the welding wire in the present invention is
An oxide film is formed, and in addition to the metal on the wire surface being changed to an oxide (chemical change), there is a fine wire surface asperity shape (physical change) due to this oxide film. . For this reason, in the wire for welding in the present invention, a solid lubricant such as MoS ₂ is more likely to be in close contact with the surface of the wire as compared with a normal wire for welding. That is,
By attaching or applying a solid lubricant such as MoS ₂ to the wire surface, the feeding resistance is further reduced, and
The variation in the feeding resistance due to the difference in the part of the wire is suppressed, and the feeding property can be maintained well even in the case of intermittent welding in a severe feeding system.

0.002 g of MoS ₂ deposited or coated
If it is less than / m < ² >, the above-mentioned effect is inadequate. Meanwhile, M
When the adhesion or application amount of oS ₂ exceeds 0.60 g / m ² ,
If the wire feeding system is severe, such as bending a long conduit tube, intermittent welding etc. may cause MoS ₂ to fall off the surface of the wire, and the dropped MoS ₂ will be in the conduit tube. As a result, the wire feeding performance is degraded. Therefore, in the case where MoS ₂ is attached or applied to the surface of the wire, the attached or applied amount is set at 0.
It is preferable to set it as 002 to 0.60 g / m ² .

When a lubricant other than MoS ₂ is attached to or coated on the surface of the wire, its electrical resistance is preferably comparable to that of MoS ₂ .

Electric resistance of lubricant: Preferably, 10 ^-4
Similar to 10 ⁺⁴ Ω · cm MoS ₂ , the adhesion resistance is further lowered by depositing or applying other lubricants to the surface of the wire, and the dispersion of the transmission resistance due to the difference of the wire portion Can be suppressed. However, although the details are unknown, when the electrical resistance of the lubricant exceeds 10 ⁺⁴ Ω · cm, or when the electrical resistance is less than 10 ⁻⁴ Ω · cm, the improvement of the feedability is not observed. Not only that, the feedability may be degraded.
Therefore, when a lubricant other than MoS ₂ is attached or applied to the surface of the wire, its electrical resistance is 10 ^{-4 to} 10 ⁺⁴ Ω ·
It is preferably cm. Moreover, the adhesion or application amount in this case is 0.002 to 0.60 g as in MoS ₂
It is preferable to set it as / m < ² >.

Incidentally, the welding wire in the present invention can be used as a wire in other packaging form, for example, a packed wire, in addition to the spooled wire. Also in this case, the wire feedability is good. A packed wire is one in which welding wires are neatly arranged in a pack, and when viewed from the top of the pack, the arrangement of the wires has a flower pattern. By arranging the wires regularly, the wires can be easily pulled out of the pack. However,
In the conventional packed wire, since the frictional force between the wires in the pack is small, vibration during transportation disturbs the arrangement of the wire and breaks the flower pattern, making it difficult to pull out the wire and causing wire feeding failure. It could have been. Since the welding wire in the present invention has a large frictional force on the surface of the wire as described above, there is no possibility that the arrangement of the wire may be disturbed by vibration during transportation. For this reason, the welding wire in the present invention can be used as a packed wire.

The welding wire in the present invention has the effect of improving the productivity in wire winding after finish wire drawing. In particular, when the welding wire is aligned and rewound on the spool, winding distortion is less likely to occur and the refolding speed can be increased by about 10% as compared with a normal wire.

Furthermore, the welding wire of the present invention can be a flux cored wire (FCW) and a solid wire (SAW).
Or the like.

[0048]

EXAMPLES Examples of the present invention will be described below in comparison with comparative examples outside the scope of the claims. First,
The manufacturing process of the solid wire will be described. Table 1 below
Prepare a raw wire (diameter 5.5 mm) of the chemical composition shown in the following table, descale → primary wire drawing → annealing → pickling (washing with acid solution) → finish wire drawing → surface control → surface control → The product diameter is 0.8, 1.2 or 1.6m by re-rolling sequentially
It was set as a solid wire without Cu plating of m. The winding form of each Cu non-plated solid wire was a spool wound wire or a packed wire.

At the time of surface control, the surface of each wire is polished to form an uneven shape on the surface of each wire, and then the oxide film is formed by high temperature oxidation treatment in the atmosphere for a short time by electrolysis (anodizing treatment) or induction heating. It formed. And
After the formation of the oxide film, a feed lubricant was applied. The amount of lubricant applied to each wire is 0.1 to 1.0 g per 10 kg of wire.

[0050]

[Table 1]

Next, the process of manufacturing the flux cored wire will be described. After preparing a mild steel hoop (thickness 0.9 mm, width 13 mm) of the chemical composition shown in Table 2 below, and filling the flux shown in Table 3 below so that the flux ratio will be 15 to 17% by weight , Forming, wire drawing, surface control and rework, product diameter 1.2, 1.4 or 1.
A 6 mm Cu non-plated flux cored wire was obtained.
The winding form of each Cu non-plated flux cored wire was a spool wound wire.

At the time of surface control, the surface of each wire was polished to form an uneven shape, and then an oxide film was formed by high temperature oxidation treatment by induction heating. After oxide film formation, 0.05 to 0.5 g of a feed lubricant was applied to each wire per 10 kg of wire.

[0053]

【Table 2】

[0054]

[Table 3]

In Table 3 above, the metal component is F
e, Si, Ni, Cr, Mo and Mn and intermetallic compounds, and the slag forming agent is Ti, Si, Mn, Al, Z
oxides of r, Ca, Mg and Ba.

Also, solid wire (A, B and C in Table 1 above) can be obtained by adding MoS ₂ into a wire drawing lubricant and drawing it, and applying a MoS ₂ dispersion to the wire of the final product. ) and was applied MoS ₂ in the flux cored wire (F in Table 2 and Table 3).

Next, the specific surface area of each welding wire,
In addition to measuring the surface properties of various wires of natural potential and MoS ₂ deposition amount, the feedability in intermittent welding and continuous welding was investigated for two types of feed systems, and wire drawability was further investigated. The measurement method and survey method of each item are shown below. First, a method of measuring the surface properties of the wire will be described.

Specific Surface Area Measurement Method As described above, the actual surface area of the wire surface measured in three dimensions is S _a and the apparent area of the wire surface is S _m , the specific surface area of the wire ((S _a / S _m ) -1) was calculated.

Self- Potential Measurement Method The wire surface is washed and degreased with an organic solvent, and then a 0.1 mol / l sodium chloride solution having a temperature of 30 ° C. is prepared, and the surface of this sodium chloride solution is released to the atmosphere. The tip of the wire after washing (several 10 mm) was immersed in the solution while blowing Ar, and after 300 seconds, it was measured based on the saturated sweet potato electrode.

Method of determining MoS ₂ deposition amount A portion (10 to 50 g) of the wire is taken from the wire for welding. Next, a 36% aqueous HCl solution is diluted with the same volume of distilled water as this aqueous HCl solution, and a portion of the above-mentioned wire is immersed in the obtained diluted hydrochloric acid to peel MoS ₂ from the surface of the wire. A portion was removed from the diluted hydrochloric acid. M
Since oS ₂ does not dissolve in hydrochloric acid, it floats or precipitates in diluted hydrochloric acid, and this diluted hydrochloric acid is filtered to obtain Mo
S ₂ separated. H ₂ SO ₄ and HNO obtained MoS _{2
After 3} was added, the mixture was heated to dissolve. After cooling the obtained solution, the Mo concentration was measured by an atomic absorption device, and the MoS ₂ content was calculated from the obtained value.

Next, the method of investigating the wire feedability and the method of evaluating the wire drawability will be described.

[0062] delivery system 9 is a side view showing the delivery system a used in this embodiment, FIG. 10 is a side view showing the delivery system b used in this embodiment. As shown in FIG. 9, in the delivery system a, the conduit tube 21 is straight and shows a normal delivery system. Further, as shown in FIG. 10, the feed system b shows a severe feed system, and a loop 21a (3 turns) with a diameter of 300 mm is formed in the central part of the 6 m conduit tube 21 and the curvature 0 is near the tip. Each test wire W which formed three curves of .01 (R = 100 mm), attached the curved torch 23 to the tip, and wound around the wire spool 24
Were fed into the conduit tube 21 by the feed roll 25 and welding was performed.

In the case of a pack wire, the packed wire is loaded on a truck, and Kanagawa → Osaka (transfer to another truck) → Hiroshima (transfer to another truck) → Kyoto (transfer to another truck) → Kanagawa After transportation in the order of, the feedability was examined. In the case of a spool wound wire, it was not transported.

Intermittent welding conditions and evaluation method As a base material, tensile strength is 490 N / mm ² grade, thickness is 1
A 2 to 20 mm high tensile steel was prepared. The distance between the tip and the base material is 25 mm, and CO ₂ as a shielding gas
The welding was carried out while draining at a rate of 25 liters / minute. The welding current is 270 to 350 (DC) A, the voltage is 28 to 32 V, and the welding speed is 30 to 35 cpm. In addition, after one minute of welding, welding was stopped for 30 seconds, and 100 cycles of intermittent welding were performed with this welding and stopping as one cycle. ○ for which no penetration occurred ○
(Good), those with less than 3 occurrences of penetration △
(Normal), those in which penetration occurred three or more times were evaluated as x (defect).

Continuous welding conditions and evaluation method Continuous welding for one hour was carried out twice under the same conditions on the same base material as in the case of intermittent welding. In the case where the feeding of the wire did not stop during continuous welding was evaluated as ○ (good), and in the case where the feeding of the wire was stopped once or more, it was evaluated as x (defect).

Evaluation Method of Wire Drawability When the die life is more than 30% longer than the average value (15 tons / die) of the conventional example, ◎ (excellent), average value ± 30
Those with% or less were evaluated as ○ (good), and those with less than 70% of the average value were evaluated as x (poor).

All of the above evaluation items were judged to be ○ (good) or better, and when there was only one x (defect), it was determined to be x (defect). The obtained results are shown in Table 4 below for Examples 1 to 8 and Comparative Examples 1 to 32.
Is shown in Table 5 below.

[0068]

[Table 4]

[0069]

[Table 5] The relationship between the specific surface area and the natural potential is shown in Table 6 below for the examples and comparative examples.

[0070]

[Table 6]

As shown in Tables 4 and 6 above, Example 1
-8, the natural potential is -412, -596, -4
52, -452, -519, -540, -441 and-
The thickness of the oxide film was appropriate, within the range defined in the present invention, which is 426 mV. Also, the specific surface area is 0.
00015, 0.0030, 0.0054, 0.005
4, 0.041, 0.048, 0.048 and 0.00
An appropriate asperity shape was formed on the surface of the wire, which is within the range defined in the present invention and 22. Therefore, intermittent weldability,
Neither continuous weldability nor wire drawability was determined to be good without defects. In particular, in Examples 2 to 4, since the specific surface area was 0.001 to 0.035, the drawability was extremely good. In addition, Example 2,
In 5, 6 and 7, because the application amount of MoS ₂ is appropriate,
Even in the case of intermittent welding under severe conditions, the feedability is good.

On the other hand, in Comparative Examples 1 to 32, as shown in Tables 5 and 6 above, all were determined to be defective. Comparative Example 1
The welding wires of {circle around (8)} to {circle around (18)} are bright finish wires (wires not having an oxide film formed thereon, or wires having an extremely thin oxide film generated naturally).
For this reason, in Comparative Examples 1 to 8 and 18, the natural potential is -726, -631, -610, -634, respectively.
-634, -659, -706, -726, -665 m
V was lower than the range defined in the present invention. As a result, regardless of the shape, size, and winding form of the wire, the feed resistance is varied to cause penetration, and the feedability at the time of intermittent welding is deteriorated.

Further, in Comparative Example 1, since the specific surface area of the wire is smaller than the range defined in the present invention of 0.00007, the wire surface becomes excessively smooth, and in addition to the feedability at the time of intermittent welding, wire drawability Has deteriorated. In Comparative Example 18, since the specific surface area is 0.055, which is larger than the range defined in the present invention, variations occur in the feed resistance, and are added at the time of intermittent welding,
The feedability also deteriorated during continuous welding.

In Comparative Examples 2 to 8, the drawability was good because the specific surface area of the wire was within the range defined in the present invention. Particularly in Comparative Examples 4 to 8, the specific surface area is 0.0.
Since it was 01 to 0.035, the drawability was very good.

Comparative Examples 9 to 17 are baking wires (wires in which the oxide film is thick and the film is black). Therefore, in Comparative Examples 9 to 17,
The spontaneous potentials are -389, -389, -211,-respectively.
390, -362, -390, -390, -377,-
320 mV, which is higher than the range defined in the present invention.
As a result, regardless of the shape, size, and winding configuration of the wire, the feed resistance is varied to cause penetration.
The feedability at the time of intermittent welding deteriorated.

Further, in Comparative Example 12, since the specific surface area of the wire is 0.00005, which is smaller than the range defined in the present invention, the wire surface becomes excessively smooth, and in addition to the feedability at the time of intermittent welding Has deteriorated. In Comparative Example 17, since the specific surface area is 0.053, which is larger than the range defined in the present invention, the feed resistance varies, and the feedability is deteriorated also in continuous welding in addition to intermittent welding.

In Comparative Examples 9-11 and 13-16,
Since the specific surface area of the wire was within the range defined in the present invention, the wire drawability was good. Particularly, Comparative Examples 9 to 10, 14
In ̃16, since the specific surface area was 0.001 to 0.035, the drawability was extremely good.

In Comparative Examples 19 to 26, the specific surface areas were 0.00007, 0.00004, and 0.00, respectively.
005, 0.00006, 0.00006, 0.000
08, 0.00008, 0.00009, which is smaller than the range defined in the present invention. For this reason, the wire surface became too smooth and wire drawability deteriorated. However, since the natural potential is within the range defined in the present invention, the feedability in intermittent welding and continuous welding was good.

In Comparative Examples 27 to 32, the specific surface areas were 0.051, 0.052, 0.051, 0.
056, 0.059, 0.059, which is larger than the range defined in the present invention. Therefore, the feed resistance varies along the longitudinal direction of the wire, and the feedability at the time of continuous welding is deteriorated. However, since the natural potential was within the range defined in the present invention, the feedability in intermittent welding was good.

The above results will be described based on Table 6 above. Comparative Examples described in the column where the spontaneous potential exceeds -400 mV and the column where the spontaneous potential is less than -600 mV (Comparative Examples 1 to 1
In 8), the feedability at the time of intermittent welding was poor. Also,
In the comparative examples (comparative examples 1, 12, 19 to 26) described in the column having a specific surface area of less than 0.0001, the drawability was poor. In the comparative example (Comparative example 17, 18, 27-32) as described in the column whose specific surface area exceeds 0.05, the feedability at the time of continuous welding was unsatisfactory.

Next, lubricants other than MoS ₂ having various electrical resistances are applied to the welding wire shown in the above-mentioned second embodiment, and the result of investigation of feedability will be described.

First, (CF) _n (fluorinated graphite), BN (boron nitride), and (-CF ₂ -CF _2- ) _n (PTFE: polytetrafluoroethylene) having extremely high electric resistance compared to MoS ₂ Were prepared as lubricants, and each lubricant was applied to a welding wire at 0.002 to 0.60 g / m ² , and the feedability was examined in the same manner as in the above-described example. As a result, the improvement of the feedability was not recognized, but there were also cases where the feedability deteriorated.

Next, Ti, whose electrical resistance is approximately equal to MoS ₂
S ₂ , ZrS ₂ , MoTe ₂ and TiSe ₂ are prepared as lubricants, and each lubricant is added to the welding wire 0.002 to 0.
60 g / m < ² > application | coating was carried out and delivery property was investigated similarly to the above-mentioned Example. As a result, like MoS ₂ , the feedability in the severe feed system was improved.

[0084]

As described above, according to the welding wire of the present invention, the concavo-convex shape is formed on the surface of the wire so that the specific surface area is within the predetermined range, and the natural potential is predetermined. Since the oxide film is formed on the surface of the wire so as to have a value, wire feedability is good, and penetration of the wire can be prevented.

Brief Description of the Drawings

FIG. 1 is a schematic view showing a real surface in a minute area of a wire surface by a three-dimensional orthogonal coordinate system.

FIG. 2 is a schematic view showing a measurement area of a specific surface area of a wire surface.

FIG. 3 is a schematic view showing a mesh for dividing a measurement area in order to calculate an actual surface area.

FIG. 4 is a schematic view showing a height position of a real surface at each intersection of meshes by a three-dimensional orthogonal coordinate system and approximating the real surface with a connected triangle.

5 is a schematic view showing a method of calculating the area of the triangle of FIG. 4;

FIG. 6 is a cross-sectional view showing a spool.

7 is a cross-sectional view showing the spool shown in FIG. 6 in an enlarged manner, showing a state in which penetration occurs.

8 is a cross-sectional view showing the spool shown in FIG. 6 in an enlarged manner, showing a state in which penetration occurs; FIG.

FIG. 9 is a side view showing a conventional feeding system used in the present embodiment.

FIG. 10 is a side view showing a severe feeding system used in the present embodiment.

[Description of the code]

DESCRIPTION OF SYMBOLS 1; Wire 2; Real surface 3; Apparent surface 21; Conduit tube 21a; Loop 23; Curved torch 24; Wire spool 25; Feed roll 51; Spool support 52; Spool main body 53; Bottom plate 54; Shaft 56; welding wires 56a, 56b, 56c, 56d, 56e, 56f, 5
6g, 56h, 56i, 56j, 56k, 56l, 56
m, 56n, 56p; wire portion 57; hatching portion 58; through hole 59; side plate 60; bearing portion

 ── ── ── ── ──続 き 続 き Continuation of the front page (72) Inventor Shinji Sakashita 1-chome, 5th and 5th Takatsukadai, Nishi-ku, Kobe City, Hyogo Pref.

Claims (3)

[Claim of claim] Assuming that the actual wire surface area in the measurement area is S _a (mm ² ) and the apparent area in the measurement area is S _m (mm ² ), the formula ((S _a / S _m )-
The wire specific surface area represented by 1) is 0.0001 to 0.05, and after degreasing the wire surface, the temperature is 3
3 in 0.1 mol / l sodium chloride solution at 0 ° C.
A welding wire characterized in that a natural potential after immersion for 00 seconds is -600 to -400 mV based on a saturated sweet potato electrode. 2. The welding wire according to claim 1, wherein 0.002 to 0.60 g / m ² of MoS ₂ is adhered to or applied to the surface. 3. The surface has an electrical resistance of 10 ^{-4 to} 10 ^+4.
0.002 to 0.60 g / m of lubricant that is Ω · cm
^2. The welding wire according to claim 1, which is adhered or applied.