JP2002283055A - Method for feeding flux-cored welding wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for feeding a flux-cored welding wire by which excellent feedability is maintained even for a long torch having a liner length of 12 m or over. SOLUTION: In this method for feeding the flux-cored welding wire, the flux-cored welding wire having surface lubricant thereon is fed to a liner of 12-27 m by a push system of a plurality of pairs of feed rollers at a feeding resistance R satisfying the inequality R<b (kgf) (where, b is the critical buckling resistance (kgf) of the wire), and at a slip ratio S satisfying S<=2R(%) (where, R is the feed resistance (kgf)).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for feeding a flux-cored wire for welding used for welding such as semi-automatic arc welding.

[0002]

2. Description of the Related Art Generally, CO ₂ gas shielded arc welding,
For MIG welding and the like, a flux-cored wire for welding having a small diameter (0.8 to 1.6 mm) is used. When using this wire, the wire is pulled out of a spool or a pail pack by a feed roller (steel or ceramic or the like) of a wire feeder, and is pushed into a liner contained in a subsequent conduit cable and passed through the liner. Then, a method of feeding the power to a power supply tip in a welding torch attached to the end of the cable is employed (push method). A voltage is applied to the wire between the power supply tip and the material to be welded, and arc welding is performed. The liner used here is a flexible guide tube formed by spiraling a metal wire.

[0003] According to this method, there is an advantage that welding can be performed relatively easily by laying the cable along the above-mentioned location even in a place where the welding location is narrow or has a height difference such as a shipbuilding site. . However, the welding cable for the flux-cored wire used for welding at a normal shipyard welding site is 6 m long, and the welder finishes the welding work on each block of the hull, and when the welding work is completed, the wire feeder with a spool ( (20-30 kg in weight) while moving to the next block, leading to a reduction in work efficiency as well as a physical burden.

In recent years, for the purpose of further improving the efficiency of the welding operation, that is, in order to continue the welding operation by moving between the blocks without moving the wire feeder, it is desired to make the welding cable as long as possible. Specifically, a demand for a long cable of 12 m or more has been increasing. However, when the liner length is about 6 m, there is no particular problem, but when the liner length is longer than 12 m, the resistance that the wire receives from the liner becomes very large, so it is extremely difficult to realize good feedability by the push method. It is. Poor feedability causes problems such as irregular welding arcs, irregular bead shapes, poor fusion, and undercuts.

Heretofore, several improvements have been proposed for the purpose of ensuring good feedability. As an improvement plan from the welding wire side, for example, Japanese Patent Application Laid-Open No. 58-135799 discloses a welding wire in which a specific amount of a solid lubricant is applied to the surface of the wire. However, it is difficult to control the amount of the lubricant attached, and there are places where the lubricant is excessively attached, and the lubricant is unevenly attached, which is not satisfactory. If the lubricant is excessively attached, slipping easily occurs in the feed roller.

[0006] As an improvement plan from the conduit liner side,
For example, Japanese Patent Application Laid-Open No. 9-70665 discloses that by increasing the winding interval of the liner portion to 0.1 to 2.0 mm, the chance of the wire contacting the liner is reduced, and the lubricating oil film is less likely to break. The technology is shown. However, it is not so effective in reducing the resistance when the liner is severely curved.
As an improvement plan from the feed roller side, for example,
Japanese Patent Application Laid-Open No. 77570 discloses a feeding roller in which a fine uneven surface (knurled) inclined at a predetermined angle with respect to the feeding direction of a wire is engraved in a roller groove to prevent slip.

However, knurled eyes are too large,
Because the blades bite into the wire, the wire surface is deformed, causing an increase in resistance when passing through the liner. In addition, if there is a large amount of debris from the wire surface and this accumulates in the liner, it also causes an increase in resistance. In addition, many proposals have been made, but the fact is that welding using a long torch having a liner length of 12 m or longer has not yet achieved good feedability by a push method.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a method of feeding a flux-cored wire for welding which can maintain a good feedability by a push method even if the length of the torch is 12 m or more. The aim is to provide a method.

[0009]

(1) Feeding resistance R <b (kgf) (b;
Wire buckling limit resistance kgf), slip rate S ≦ 2R
(%) (R; feeding resistance kgf), which is a method of feeding a flux-cored wire for welding to be fed to a liner having a length of 12 to 27 m. (2) Flux-cored wire for welding has a breaking load of 40
The method for feeding a flux-cored wire for welding according to the above (1), which is 0 to 850 N.

(3) The feeding roller has a total pressing force ΔP ≧ 15.
kgf, wherein the individual pressing force P ≦ 30 kgf is the method for feeding a flux-cored wire for welding according to the above (1) or (2). (4) The liner is in the cable and has a minimum radius of curvature Cm
The method for feeding a flux-cored wire for welding according to any one of the above (1) to (3), wherein in ≧ 50 mm is used. (5) The welding flux-cored wire according to any one of (1) to (4), wherein the welding flux-cored wire is a seamless wire.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the contents of the present invention will be described in detail. In order to perform stable welding, it is important to supply the welding wire to the weld at a predetermined constant speed. The wire is pushed into the liner by the feed force of the feed roller, while receiving resistance from the inner surface of the liner due to contact friction. At this time, if the degree of bending of the liner is large or long, and the feeding resistance from the liner increases,
Since the slip easily occurs between the feeding roller and the wire, the pressing force of the feeding roller is increased to increase the feeding force.

However, if the pressing force is too strong, problems such as crushing and deformation of the wire and buckling in the liner occur. If the liner length is 6 m, the feeding balance can be relatively easily adjusted by adjusting the pressing force. However, with a long liner of 12 m or more, the resistance is high, so that the adjusting range of the pressing force is narrow and a good feeding state is maintained. It will be very difficult to do. In the present invention, a flux-cored wire for welding having a surface lubricant is used, and the feed roller uses a plurality of pairs of feed rollers to feed the wire to a long liner of 12 to 27 m in a push manner. .

A description will be given with reference to the feeding state diagram of FIG. The feedability state diagram expresses the feedability state by the feed resistance R (kgf) and the slip ratio S (%). The feed resistance R is plotted on the horizontal axis, and the slip rate is plotted on the vertical axis (logarithmic axis). Take. In Figure 1, the horizontal axis 15kgf the maximum resistance R _max, the vertical axis represents the maximum slip rate S
_max is 100% of full scale. The feedability state diagram is divided into three areas: a good feedability area (A), a buckling occurrence area (B), and an excessive slip area (C). The feedability is evaluated based on where the coordinates in the state diagram determined by R and S obtained by performing the feedability test are in three regions. The slip ratio S (%) is
From the wire feed speed Vr, which is the peripheral speed of the wire contact point of the feed roller V groove, and the actual wire speed Vw, S = ｛(Vr−V
w) / Vr｝ × 100 (%).

The good feedability region (A) has a feed resistance R (k
gf) is a region where the feeding state is good where the wire buckling limit or less and the slip ratio S is 2R% or less. In this region, the smaller the feed resistance R and the slip ratio S in the direction of the arrow e, the better the feedability. Feeding resistance R ≦ 7k in region A
A region having a better gf is defined as a special A region. In the buckling occurrence area (B), the feed resistance R received by the wire from the liner is large, and the feed resistance R is the buckling limit resistance b of the wire.
Once in this region, beyond the (buckling limit line b), the wire begins to meander in the liner. The meandering increases the number of contact points of the wire with the inner surface of the liner, so that the resistance also increases. This further snakes and increases the resistance. After repeating the meandering and the resistance increase, the wire eventually buckles, the feed stops, and the arc breaks. The buckling limit resistance b is the limit resistance at which the wire receives resistance in the liner and starts to meander. The buckling limit resistance b is determined by the wire diameter, cross-sectional shape, rigidity, liner inner diameter, and the like.

In the overslip region (C), the slip ratio R is higher than the feed resistance in a region where the slip ratio S exceeds 2R%, and R and S are unbalanced. An area where the arc is easily disturbed and hinders welding. If the feed function of the feed roller is weakened due to an excessive amount of lubricant on the wire surface or a large feed resistance, this area is entered. According to the present invention, in welding using a liner having a length of 12 m or more, the feedability is improved by first preventing the buckling from occurring in the buckling region (B) and then preventing the welding from entering the excessive slip region (C). A stable wire feed in the region (A) is realized.

The feed resistance and slip ratio can be measured by the method shown in FIG. FIG. 2 shows the outline of the feedability tester. The wire feeding device 1 is slidably provided on a rail (LM guide) 3 while being disconnected from the power cable entrance 2. The wire 4 fed from the spool 8 is fed by a feed roller 6 into a subsequent liner in the power cable 5 by a push method. When the wire receives a reaction force from the liner, the feeding roller 6 receives the reaction force, and the feeding device 1 moves in a direction opposite to the wire feeding direction. The feeding device 1 is pressed against the load cell 7, and the load cell detects this force as a feeding resistance R.

The wire speed detecting roller (with a rotary encoder) 9 detects the actual wire speed Vw, and the driving roller (with a rotary encoder) 10 detects the wire feed speed Vr. By calculating Vw and Vr, a slip ratio S = {(Vr−Vw) / Vr} × 100 (%) is calculated. Further, the pressure P is measured by the load cell 11 attached to the pressure roller. A liner of 12 m or more is used in a bent state in addition to being long, so that the feeding resistance becomes extremely high. To resist this, the wire surface should have good slipperiness against the liner so that the feed resistance does not exceed the buckling limit. In order to prevent excessive slip, it is necessary that the feeding roller is not easily deformed even if the pressing force of the feeding roller is increased.

In the case of a seamless type wire (a cross section is shown in FIG. 3), since the filling flux 13 is completely confined by the outer metal 12, the surface treatment applied to the outer surface is not affected at all. That is, since all kinds of surface treatments necessary to reduce the feeding resistance can be performed, the above measures can be taken. In addition, a seam (non-joined part) to the outer skin 12
Since it is closed without any gaps, the strength in the cross-sectional direction is high, and it is difficult to be deformed by the strong pressing force of the feed roller, and the above measures can be taken.

On the other hand, in the case of the seamed wire, the outer skin 14 has a seam (hoop) edge seam 15 along the wire longitudinal direction. The seams are not joined. FIGS. 4 (a) and 4 (b) show cross sections of a representative example of the seamed wire. FIG.
In the type in which the hoop edge is simply abutted in (a), the feeding roller is easily deformed when strongly tightened, and easily buckles in the liner. In addition, the surface treatment has the following restrictions.

That is, there is a limit to the method of lubrication treatment applied to the wire surface. When a plating treatment or a liquid treatment such as wet drawing with a lubricating oil is performed, the treatment liquid enters the inside of the wire from the joint 15 of the outer skin, and the flux 1
3, so that the liquid treatment cannot be performed substantially. For this reason, it is difficult to reduce the feeding resistance. Because of its cross-sectional structure, it tends to buckle, so the buckling limit resistance at the time of feeding is low, and the feeding resistance is likely to exceed this for the reason.
For this reason, even if the pressing force is increased and the feeding force is increased in order to counter the feeding resistance, the buckling immediately exceeds the buckling limit resistance and buckles. In addition, due to its cross-sectional structure, it is weak against compressive force, and when the pressing force is increased, the wire sheath 14 is easily deformed.

On the other hand, the seam lines of the hoop edge are laid on top of each other and overlapped to increase the contact area of the seam (FIG. 4B).
The above-mentioned drawbacks of the simple butt type are improved in the wrap type, and the feeding performance close to a seamless wire can be obtained. For these reasons, a wire with a seamless cross-sectional structure of the flux-cored wire of the present invention is recommended. However, as described above, even with a seamed wire, the feeding performance is close to that of a seamless wire by devising the seam shape or surface treatment. Any wire can be used. The recommended rigidity of the wire is 400 to 850 N in terms of breaking load. The reason is 400N
If it is less than 3, the wire is easily deformed by the strong pressure of the feed roller, and the wire is easily buckled when passing through the liner. On the other hand, if it exceeds 850 N, it becomes difficult for the wire to follow the curve of the liner, and as a result, the inner surface of the liner is strengthened, so that the contact resistance increases.

As a measure against the high resistance from the liner, a lubricant is attached to the surface of the wire to improve the slipperiness between the liner and the feeding resistance so as not to exceed the buckling limit. As the surface lubricant, a solid lubricant, a lubricating oil, plating or the like can be used alone or in combination. In the case of a seamless wire, there is no restriction on the surface treatment method. That is, it is possible to freely perform a treatment for maximizing the slipperiness on the liner on the wire surface. That is, a plating treatment such as copper plating can be performed on the surface, or a liquid treatment for attaching a lubricating oil can be performed. In the case of a wire having a seam, a light liquid treatment except for plating can be performed with the improved cross-sectional structure described above. Copper plating has a function of increasing rust prevention and increasing electrical conductivity, in addition to a function as a lubricant. The plating film thickness is about 0.1 to 0.7 μm in the case of copper plating.

Examples of the solid lubricant include MoS ₂ , WS ₂ , other polytetrafluoroethylene (PTFE), graphite, dry drawing lubricant and the like. These solid lubricants adhere to the surface of the wire, reduce the coefficient of friction between the inner wall of the liner and the wire, and have the effect of suppressing an increase in feed resistance. The amount of the solid lubricant to be applied is 0.1 to 2.0 g per 10 kg of wire (g / 10 kg
W). If it is less than 0.1 g / 10 kgW, no effect of suppressing an increase in the feeding resistance is recognized, and no improvement in the feeding property can be expected. Conversely, if it exceeds 2.0 g / 10 kgW, it will be excessively adhered to the wire surface, the feed roller will slip greatly, and stable feed will be difficult. Desirably 1.0g / 10k
It is better not to exceed gW.

The lubricating oil reduces the coefficient of friction between the inner wall of the liner and the wire, as in the case of the solid lubricant, and suppresses an increase in the feeding resistance, by adhering to the entire wire surface. The feed lubricating oil may be any of animal and vegetable oils, mineral oil and synthetic oil. The amount of the lubricating oil supplied was 0.1 kg per 10 kg of wire.
It is desirably 1 to 1.5 g (g / 10 kgW). If it is less than 0.1 g / 10 kgW, the effect of suppressing the feed resistance is small. On the other hand, when it exceeds 1.5 g / 10 kgW, it excessively adheres to the wire surface, and the feeding roller easily slips. Further, since the lubricating oil is decomposed by the welding heat to generate a large amount of hydrogen, deterioration of the weld metal material due to an increase in the amount of diffusible hydrogen is likely to occur. Desirably 1.0g / 10kgW
It is better not to exceed.

It is desirable to form a surface roughness (unevenness) on the surface of the wire. The formation of the surface roughness (irregularities) is expected to have a function of adhering a minimum amount of lubricant (solid lubricant, lubricating oil) to the wire surface as a lubricant pool and a function of preventing overslip in the feed roller. The recommended range is JIS
The surface roughness in the wire longitudinal direction defined by B0601-1994 is 0.05 to 0.25 μm in arithmetic average roughness Ra.
And In addition to this, the load length ratio tp in the wire longitudinal direction
(Cutting level Cv = 30%) may be about 20 to 90%. The Ra and tp are measured with a stylus type roughness meter (needle tip 5μ).
m) can be obtained as an average value of the measured values in the longitudinal direction at four positions at 90 ° intervals in the circumferential direction of the wire.

Ra is an index indicating the depth of roughness.
If it is less than 05 μm, the height difference between the uneven portions becomes too small, and the function of holding the lubricant becomes poor. Conversely, if it exceeds 0.25 μm, the height difference between the uneven portions becomes too large, and the adhesion of the lubricant becomes excessive. Easy to be. In addition, tp is an index indicating the roughness profile of the wire surface. If it is less than 20%, the convex portion becomes too small, and if it exceeds 90%, the concave portion becomes too small. Is scarce. If the function of holding the lubricant is poor, it is difficult to stably adhere an appropriate amount, causing excessive resistance and excessive slip and causing variation in the feeding property. Excessive lubricant adhesion causes excessive slip.

The feed roller is generally composed of a pressure roller and a driving roller having a V-shaped groove. In the case of the one-pair type, the pressing force for obtaining the necessary feeding force is procured in one place, so that a strong pressure is applied, and the wire cross section is easily deformed or the surface is easily peeled. In the case of a multiple pair type, there is no need to worry because the required pressing force is dispersed and the individual pressing force per pair is reduced. For this reason, the present invention uses multiple pairs of feed rollers. Further, in the multiple pair type, the contact area between the roller and the wire increases, so that there is an advantage that the feeding force is large even if the total pressing force is the same as in the single pair type. Although three or more pairs of feed rollers may be used, two pairs can sufficiently exhibit this effect.

FIG. 5 is a side view of the feed roller (a view as seen from the longitudinal direction of the wire). In FIG. 5, one pair of feed rollers 1
6 is an opening angle which is driven to rotate by a feed motor, about 30 °
(25-40 °) drive roller 1 around which V-groove 17 is provided
8 and a pressure roller 19 for pressing the wire 4 into the V groove 17. FIG. 6 shows two pairs of feed rollers (W rollers) 20. In the W roller 20 of FIG. 6, the driving rollers (21-1) and (22-1) are on the lower side, and the pressing rollers (21-1)
-2) (22-2) is on the upper side. The driving mechanism is a driving roller (2) rotated by a feeding motor (not shown).
The driving force of 1-1) is transmitted to the other driving roller (22-1) via the intermediate gear 23.

On the other hand, the pressurizing mechanism uses the fulcrum (24-
1) Lateral arm (26-1) (2) of L-shaped arm (25-1) (25-2) rotatably used as (24-2)
6-2), the pressure rollers (21-2) and (22-2) are attached, and the two L-shaped arms (25-1) and (25-2) are attached to the substrate 30 in a state where the two pressure rollers face each other. By pressing the pressure handle 29 in the direction in which the vertical arms (27-1) and (27-2) approach each other to compress the spring 28, the pressure roller is moved in the direction of the drive roller, 4 is pressurized. Of course, the drive mechanism and the pressure mechanism may be of another type.

The feed roller (generally made of steel or ceramic) is used to effectively suppress slippage with the wire.
The arithmetic average roughness Ra of the roller groove in the circumferential direction is 0.2 to 5.
It is preferably about 0 μm. If Ra is less than 0.2 μm, it is too smooth and slips easily.
When the thickness exceeds 0 μm, the surface becomes coarse, so that the wire substrate is easily damaged.
It easily adheres to the surface and slips. Ra was measured by using a stylus type roughness meter (needle tip 5 μm) and a 90 ° circumferential interval 4 on the groove surface.
It can be obtained as an average value of the measured values in the circumferential direction at the location.

The surface of the V-groove may be subjected to a treatment such as shot blasting or thermal spraying so that the surface is roughened so as not to exceed the above range. For multiple pairs of rollers, the total pressure ΣP ≧ 15
kgf, and an individual pressure P ≦ 30 kgf. If the total pressure ΣP is less than 15 kgf, the feeding force will be insufficient, and if the individual pressure P exceeds 30 kgf, the wire cross-section will be deformed and the wire surface will be easily peeled off like the one-pair type. is there. Wire surface peeling promotes shortening of the liner life due to foreign matter clogging.

The feeding resistance increases as the liner length increases. This is because, in addition to increasing the chance that the wire contacts the inner surface of the liner, the wire is easily meandered because the wire is fed by the push method. For this reason, in the present invention, the maximum length of the liner is limited to 27 m. The liner is a metal winding made of steel or the like, and has an inner diameter of D + (0.5 to 2.0) mm.
(D: wire diameter), the wire diameter is desirably 0.8 to 2.2 mm. That is, when the wire diameter is 1.2 mm, the inner diameter of the liner is 1.7 to 3.2 mm, and the wire diameter is 1.4 mm.
It is recommended to use a liner with an inner diameter of 1.9 to 3.4 mm. If the liner inner diameter is less than D + 0.5 mm, the wire passage becomes too narrow, and the chance of the wire contacting the inner surface of the liner increases.

On the other hand, if the distance exceeds D + 2.0 mm, the wire passage becomes too wide, and the wire tends to meander. In this case, too, the chance of the wire contacting the inner surface of the liner increases. The more contact chances, the higher the feeding resistance. If the wire diameter of the liner is less than 0.8 mm, the gap volume between the windings becomes small, and foreign matter falling off from the surface of the wire tends to block the passage, which tends to cause an increase in feed resistance. Meanwhile, 2.
If it exceeds 2 mm, there is no particular adverse effect on the feedability, but it becomes difficult to bend, making it difficult to operate the welding torch.

It is preferable that the liner in the cable be fed as straight as possible. However, in actual welding sites, there are many partitions and the cable is disposed over these. In the vicinity of the hand of the torch, welding is performed in various shapes. Liner has minimum radius of curvature C
It is desirable to use in a state where min is 50 mm or more. If the liner has at least one severely curved portion having a curvature radius C of less than 50 mm, the feed resistance becomes large, and the feed of the wire is hindered in an overslip state.
Cmin is selected by selecting the material and diameter of the cable, inserting a reinforcing core into the cable, winding a reinforcing spiral tube around the cable, or adjusting it by the route of the cable or the curvature of the hand of the torch, etc. To

[0035]

EXAMPLES The effects of the present invention will be specifically described below with reference to examples. Perform a feedability test with different feed conditions,
The feeding method of the present invention was evaluated by comparing the feeding performance. The test wire used was a flux-cored wire (JIS Z3313YFW-C50DR, flux filling rate 15%) having a wire diameter of 1.2 mm and a spool wound with a wire winding weight of 15 kg. The cross-sectional shapes are shown in FIGS. 3, 4 (a) and 4
Two types, a seamless product and an existing product shown in (b), were used.
The surface roughness of the wire is about Ra = 0.8 to 1.6 μm. Table 1 shows the test wires.

[0036]

[Table 1]

The roller used is a steel V-groove with an angle of 30 °.
A pair type and a two pair type were used. The circumferential roughness Ra of the V groove is 0.45 μm. Table 2 shows the V-groove rollers used. The liner used is a spirally wound steel wire having a wire diameter of 1.3 mm and an inner diameter of 2.2 mm.
The liners used were 15 m, 21 m, and 30 m in length. The radius of curvature of the torch hand curvature (FIG. 7) was defined as the minimum radius of curvature Cmin. Table 3 shows the liners used.

[0038]

[Table 2]

[0039]

[Table 3]

The feedability evaluation test was performed using the apparatus shown in FIG. 2 with the cable (liner) bent as shown in FIG. That is, the feed roller 6 causes the wire 4
Is pulled out from the spool 8 and is fed to the torch 32 at the end of the cable 5 through the liner included in the cable 5. Then, bead-on-plate welding is performed for 3 minutes between the current-carrying chip and the steel plate 33 on the turntable. 5 cables, 1 liner
5 m, 21 m and 30 m were used. In order to give a feeding resistance to the wire, an intermediate bent portion 34 in which 1 to 3 peaks having a radius of curvature of 150 mm are formed in the cable path and a hand bent portion 35 bent in an S-shape with a minimum radius of curvature (shown in Table 3). Provided. When the number of ridges at the intermediate bent portion is three, the difficulty is the highest (III), when the number is two, the difficulty (II), and when the number is one, the difficulty (I) is the most difficult. Difficulty is different.

The measurement of the wire buckling limit resistance b in Table 1 is as follows.
Feed roller No. 1 and liner no. The number of ridges at the middle bent portion of the cable is 0 to 1 ridge, 2 ridges, and 3 ridges.
The feed resistance is increased by slowly forming the peaks and four peaks, and the feed state becomes unbalanced, and the feed resistance value when the feed resistance starts to rise is measured. And The feeding was stopped immediately after the feeding resistance started to rise, and the wire was pulled out from the liner to check the occurrence of buckling. Table 4 shows the welding conditions at this time.

The evaluation of the feeding performance was made by determining the feeding resistance R and the slip ratio S.
Was measured by the above-described method, and was determined as an average value during the welding time (3 minutes). Fig. 1 shows the calculated feed resistance R and slip ratio S.
And the feedability was determined at that position. Passing difficulty of cable bending (I),
In the case of entering the area A in (II) and (III), it is judged as a pass.
Or, the case of the area C was rejected. Table 4 shows the welding conditions for the feedability evaluation test.

[0043]

[Table 4]

The results are shown in Table 5. In Table 5, No. 1 to
No. No. 18 is an example of the present invention. 19-No. 24 shows a comparative example. Invention Example No. 1 to No. 5 (using a seamless wire) has a liner bending difficulty (I
In the case of I), it was in the special A region and in the difficulty (III), it was in the A region, and the feeding property was extremely good. No. 2 and No. 4 and 2
It was confirmed that even a 1 m liner was good. No. 6 ~
No. No. 16 (using a seamless wire) entered the region A at the liner bending difficulty (II), and the feedability was good. N
o. 1 to No. The buckling limit b of 16 is 10 to 13 kgf. No. 17 and No. 18 (using a wire with a seam) is a lap seam type wire with a seam, which has a slightly higher feed resistance and enters the area B in the liner curve difficulty (II), but the area A in the liner curve difficulty (I). The feedability was almost good. No. 17 and No. 18
Has a bending limit b of 9 to 10 kgf.

Comparative Example No. 19 (uses seamless wire)
And Comparative Example No. In 20 (using wire with seam)
Since the feeding roller was a pair type, there was no feeding force, and the liner bending degree (I) entered the region C and was in an excessive slip state. Comparative Example No. In 21 (using a seamless wire), the radius of curvature of the S-curve at hand is as small as 40 mm.
In Comparative Example No. 22 (using seamless wire)
Since the liner was too long at 30 m, the comparative example no. 23
In the case of using the seamless wire, the wire had a large rigidity of 950 kgf at breakage, so the feed resistance was high, and the liner bending difficulty (I) entered the region B and exceeded the buckling limit, causing arc breaking.

Comparative Example No. 24 (use of wire with seam)
The test wire is a simple butt type seamed wire, which is inferior in slipperiness and high in feed resistance. Further, since the buckling limit is lower than that of the seamless wire, even the easiest liner bending difficulty (I) entered the region B and exceeded the buckling limit in a short time, causing arc breaking. Comparative Example No. 2
The buckling limit b of No. 4 is 8 to 9 kgf. Comparative Example No. 2
1 to No. In No. 24, the feed resistance suddenly entered the buckling limit and continued to rise thereafter, causing buckling and breaking the arc. The feeding resistance value R in the table is a measured value immediately after entering the buckling limit.

[0047]

[Table 5]

[0048]

According to the present invention, since a flux-cored wire having a surface lubricant is fed by a plurality of pairs of feed rollers, the wire is pushed by using a long torch having a liner length of 12 to 27 m. In the welding to be fed, good feedability can be maintained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a feeding state diagram.

FIG. 2 is a diagram showing an outline of a feedability tester.

FIG. 3 is a sectional view of a seamless wire.

FIG. 4 is a sectional view of a seamed wire.

FIG. 5 is a diagram illustrating a feed roller pair.

FIG. 6 is a diagram illustrating an example of two pairs of feed rollers.

FIG. 7 is a diagram showing a use state of the long torch.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Feeding device 2 Cable entrance part 3 Rail (LM guide) 4 Wire 5 Cable 6 Feeding roller 7 Load cell for feeding resistance measurement 8 Spool 9 Wire speed detecting roller 10 Driving roller 11 Load cell for applying pressure measurement 12 Skin (seamless) 13 flux 14 outer skin (wire with seam) 15 seam 16 feed roller pair 17 V groove 18 drive roller 19 pressure roller 20 feed roller (W roller) 21-1.22-1 drive roller 21-2.22 -2 pressure roller 23 intermediate gear 24-1, 24-2 fulcrum 25-1, 25-2 L-shaped arm 26-1, 26-2 horizontal arm 27-1, 27-2 vertical arm 28 spring 29 pressure handle DESCRIPTION OF SYMBOLS 30 Substrate 31 Straightening roller 32 Torch 33 Steel plate 34 Intermediate bent part 35 Hand bent part 36 Spring

Continuation of the front page (72) Inventor Masaki Abe 7-6-1, Higashi Narashino, Narashino-shi, Chiba Nippon Steel Welding Industry Co., Ltd. (72) Inventor Hiroyuki Takahashi 7-6-1, Higashi-Narashino, Narashino-shi, Chiba Pref. Inside the Technical Center of Iron Welding Industry Co., Ltd. (72) Yukio Fujiwara 7-6-1, Higashi Narashino, Narashino City, Chiba Prefecture Inside the Technical Center of Nippon Steel Welding Industry Co., Ltd. (72) Toshiyuki Izumi 7-6-6, Higashi Narashino, Narashino City, Chiba Prefecture No. 1 Inside Nippon Steel Welding Industry Co., Ltd.

Claims (5)

[Claims] 1. A welding flux-cored wire having a surface lubricant is pushed by a plurality of pairs of feed rollers by a push method.
Feeding resistance R <b (kgf) (b; wire buckling limit resistance k
gf), slip ratio S ≦ 2R (%) (R: feeding resistance kg
f) A method for feeding a flux-cored wire for welding, wherein the wire is fed to a liner having a length of 12 to 27 m. 2. A welding flux-cored wire having a breaking load of 400 to 850N.
A method for feeding a flux-cored wire for welding as described in the above. 3. The feeding roller has a total pressing force ΔP ≧ 15 kg.
3. The method for feeding a flux-cored wire for welding according to claim 1, wherein the welding flux is used at an individual pressure P ≦ 30 kgf. 4. The method for feeding a flux-cored wire for welding according to claim 1, wherein the liner is used in the cable with a minimum radius of curvature Cmin ≧ 50 mm. 5. The method for feeding a flux-cored wire for welding according to claim 1, wherein the flux-cored wire for welding is a seamless wire.