JP2001179481A - Flux cored wire for arc welding and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a flux cored wire for arc welding which shows a stable color of the wire surface, has an excellent feedability, realizes a stable arc discharge, and generates small amount of fume and sputter, even under a severe welding condition. SOLUTION: The flux cored wire for arc welding whose brightness L* of the wire surface color defined by the L*C*h color space is controlled to be 40 to 60, which has a stable feedability, and which realizes a stable arc discharge is provided by a method in which a flux cored wire having a lapping margin of 15 to 30% of the wire diameter is drawn by wet type drawing after drawn by dry type drawing with a roll or a pore die for drawing to reduce the diameter by as much as 80% or greater in a total sectional reduction rate, the invasion of hydrogen source into the wire is prevented by making use of a mixed lubricant whose dry to wet type ratio is specified as an initial lubricant in a wet type drawing, and adjusting the depositing quantity of the lubricant on the wire surface.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flux-cored wire for arc welding and a method for producing the flux-cored wire, and more particularly, to a wire having a good color tone, excellent feedability during welding, and good workability. The present invention relates to a flux-cored wire for arc welding and a method for producing a flux-cored wire having a seam capable of maintaining the above conditions.

[0002]

2. Description of the Related Art An arc welding wire includes a solid wire and a flux-cored wire. The flux-cored wire includes a wire having a seam on the outer surface as illustrated in FIGS. 1 (a) and 1 (b). There is a seamless wire in which joints are welded as shown in FIG.

[0003] Since the seamless wire is joined immediately after filling with the flux, it can be annealed, pickled, and plated in the same manufacturing process as the solid wire. Therefore, the amount of diffusible hydrogen is low, and it is excellent in rust resistance, hygroscopicity and targetability, but the number of manufacturing steps increases.

[0004] Flux-cored wires for arc welding are required to provide products of stable quality at lower cost in welding of shipbuilding, steel bridges, etc., and to manufacture them at lower cost together with improvement and stabilization of quality. Is strongly required.

[0005] A general method of manufacturing a flux-cored wire for arc welding with a seam (hereinafter referred to as a seam flux-cored wire) is to reduce the wire after flux filling to a product diameter using a roll and a hole die. I do. In the case of using a hole die, some wire drawing lubricant is required.

The wire drawing lubricant includes a dry type and a wet type. Dry lubricants are mainly composed of metal soaps and inorganic substances, to which various lubricity improvers are added.

[0007] Wet lubricants include oily lubricants mainly composed of animal and vegetable oils, mineral oils, synthetic oils and oiliness improvers, and emulsion types in which lubricating components are dispersed, emulsified and solubilized in water. Select and use.

[0008] Regarding the effect of the wire drawing lubricant, a dry lubricating wire is usually used because the flux-cored wire may enter the seam through the wet lubricating agent when it passes through a wet lubricant. In particular, most of the steel strip used for flux cored wire production is a low-carbon cold-rolled steel strip from the viewpoint of workability.
In terms of wire drawing, the surface is very smooth and the wire drawing lubricant is poorly applied, and the supply of the lubricant is not stable and is interrupted, resulting in a rough surface, which is liable to be disconnected and poor in productivity. In order to obtain efficient and stable drawability with dry die wire drawing, it is necessary to form a lubricating layer between the die and wire, but in the case of dry type, it is more difficult to supply lubricant stably to the surface of the drawn material than in the case of wet type In addition, since the lubricating layer is rough and easily broken, the lubricating layer tends to be thick. Therefore, a large amount of a thick lubricant adheres to the wire surface. Moreover,
The thickly adhered lubricant tends to peel off in the form of flakes during wire drawing, so that the amount of adhesion is not stable. If the wire surface contains a large amount of lubricant, the electric current at the tip during welding is not stable and the arc becomes unstable. Further, the deposits gradually accumulate in the conduit tube, and the feeding resistance increases and the feeding property decreases, so that it cannot be used for a long time.

Next, regarding the composition and effect of the wire drawing lubricant,
Normally, dry lubricants are mainly metallic soaps or lubricants such as graphite and MoS ₂ added to metallic soaps, so that the amount of spatter, fume and diffusible hydrogen during welding tends to increase. As one of the above countermeasures, a method of baking at the product diameter and removing the hydrogen source is known, but since the carbide remains on the surface, there are many spatters and fumes at the time of welding, and the feedability decreases due to deterioration of the lubricating component on the surface. .

[0010] On the other hand, with the automation and higher efficiency of welding, arc welding flux cored wires tend to be used more and more. However, from the point of efficiency, high current welding conditions are adopted regardless of automatic or semi-automatic welding. Tend to be. As a result, the wire feeding speed and the feeding amount are inevitably increased. or,
Building blocks will be large in terms of shipbuilding and other building efficiency. Conversely, to prevent marine pollution due to accidents such as oil leaks from tanker groundings, the structure of the hull has become complicated due to the shift to a double hull structure, and the opportunity for use in narrower areas has increased. From the viewpoint of ease of use in these narrow places, the conduit cable from the wire feeder of the welding machine to the welding torch tends to be soft and long.

However, when the supply speed of the welding wire is increased as described above and a long and bendable conduit cable is used, the frictional resistance when the wire passes through the conduit tube when the wire is fed increases. In addition, the amount of deposits on the wire surface is increased in the conduit tube, which hinders the wire feeding and makes the arc unstable, making welding impossible.

For this reason, various measures have been proposed so far for improving the feedability of the wire for arc welding, but the use conditions are becoming stricter year by year, and there is no sufficient measure.
Welders are often forced to interrupt welding under harsher conditions and struggle with cleaning up accumulated deposits and replacing worn conduit tubes.

To solve the problems of feedability and workability of these welding wires, for example, Japanese Patent Application Laid-Open No.
No. 8 discloses an arc welding wire coated with an ester comprising a higher fatty acid and a higher monohydric alcohol and a mixture of the ester and MoS ₂ , graphite or the like;
Japanese Patent Application Laid-Open No. 8-184,095 proposes an arc welding wire having a surface coated with a mixture of a solid lubricant such as graphite, molybdenum disulfide, and glass powder.

However, even in these arc welding wires, the above-mentioned soft and long conduit cable is used, and under severe conditions such as welding under high current conditions, the wire slips at the feed roll. The friction resistance inside the conduit tube is large, and the inside of the conduit tube becomes hot due to frictional heat and the heat of the welding cable wrapping the conduit liner, causing the lubricant on the wire surface to partially melt, agglomerate and uniform on the wire surface Because of no longer being coated, the feedability becomes unsatisfactory. Also,
Lubricant that has partially melted accumulates in the conduit tube and tip during prolonged welding, narrowing the wire path, increasing the feed resistance and the tip current-carrying resistance, and hindering stable arcing. There is.

Also, the seam flux-cored wire in which the U-groove forming part is filled with flux and the wire-shaped seam at both ends is not joined is formed by a process of forming, filling, drawing, and drawing into a product to form a product. Since the oil and lubricant serving as a hydrogen source enter from the upper joint, a dry wire drawing lubricant is generally used instead of a wet lubricant.

However, a technique for producing a welding wire with a joint flux by drawing by combining dry and wet drawing is disclosed in Japanese Patent Laid-Open No. 6-15485.
%, And a method for producing a flux-cored wire in which a wire is drawn by arbitrarily using a wet or dry lubricant in a region of more than 10% and less than 70%. However, as a result of various studies, the above-mentioned problem was not solved.

[0017]

SUMMARY OF THE INVENTION To enable a wet drawing of a flux-cored wire having a seam where the seam is not joined, using a soft and long conduit cable,
Even under severe conditions such as welding under high current conditions, there is little clogging in the conduit cable and accumulation of lubricant components on the feed roll, good feedability, and an arc welding wire capable of stable welding and its welding. There is an efficient manufacturing method.

[0018]

According to the present invention, the seam wrap length of the wire sheath is 15 to 30% of the wire diameter, the lightness L ^* of the wire surface is 40 to 60, and the wire surface has a solid lubricant. An arc welding flux-cored wire characterized in that an oil-based lubricant is applied thereon.

A flux-cored wire having a seam wrap length of 15 to 30% of the wire diameter filled with flux is used as a wire, and the wire is dried with a dry lubricant at a total area reduction of 8%.
The method for producing an arc welding flux-cored wire according to claim 1, wherein the wire is drawn by 0% or more, and then wet drawn using a hole die.

The dry lubricant contains 2 parts by weight of high melting point wax.
20 to 20%, and the wet lubricant contains an oil-based lubricant and a detergent in a weight ratio of 5 to 80%.

[0021] The method for producing an arc welding flux cored wire according to the present invention is characterized in that the first die lubricant for wet drawing is obtained by adding 40 to 60% by weight of a dry lubricant to a wet lubricant.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the basic concept and operation of the present invention will be described with reference to FIG. The present inventors first observed the wire feeding and arc phenomena during welding using various devices such as high-speed video and waveform analysis in order to stably maintain welding of the jointed flux-cored wire even under severe conditions. From the results and the analysis results of the wire surface, the structure of the wire surface firmly attaches a solid or semi-solid lubricant to the wire surface,
It has been found that by providing a liquid lubricant layer thereover, stable welding can be maintained for a long time even under the above-mentioned severe conditions.

First, the above-mentioned two-layered lubricant is drawn using a dry lubricant containing a high melting point wax or the like, whereby the lubricant is firmly adhered to the surface of the wire to form a lower layer. Or, by adjusting the amount of extra lubricant attached in dry drawing by wet drawing, clogging in the conduit cable and adhesion and deposition on the feed roll even under severe conduit cable use and high current conditions In addition, even in a severe bending state, the slip on the feed roll is small, and the frictional resistance in the conduit cable can be reduced, so that the wire feedability is improved and stable welding of the arc can be performed even for a long time. Dry lubricant is Mo
S ₂ , WS ₂ , polytetrafluoroethylene (hereinafter, PT
FE), graphite, graphite fluoride, and one or more metal soaps, and a high-melting-point wax is added in an amount of 2 to 20% by weight to allow a dry lubricant to be stably brought in. Prevents the attached lubricant from peeling off during wire drawing, and keeps the wire surface with a lubricant effective for feedability during welding. As the high melting point wax, a natural or synthetic product having a melting point of 50 ° C. or more is used.

As described above, wet removal by wire drawing is effective for removing excess lubricant that has adhered firmly by dry drawing, but the flux cored wire has a seam opening due to the wet drawing. When lined, lubricant enters from the joint,
When welding, the amount of diffusible hydrogen in the weld metal increases and flaps and groove-like defects are generated on the surface of the welded portion. Therefore, various methods for preventing the intrusion of a hydrogen source even by wet drawing and obtaining an appropriate amount of lubricant attached were examined.

As a result, as shown in FIG. 1 (b), when the joint of the flux-cored wire is wrapped and the lap margin L is adjusted to 15 to 30% of the wire diameter D, the contact of the joint is almost in a close contact state. Therefore, it was found that the penetration of the wet lubricant was extremely reduced. Furthermore, it has been found that the intrusion of the hydrogen source from the joint can be prevented to a level at which there is no practical problem by setting the wire diameter at the start of wet drawing to a small diameter side. That is, wet-drawing is performed after reducing the diameter to a total area reduction of 80% or more using a dry-type lubricant containing 2 to 20% of wax, and the dry-type lubricant is added to the wet-type lubricant at the beginning of wet-drawing. By using the mixed lubricant added at 40 to 60%, the penetration of the lubricant from the seam could be prevented.
This technology makes it possible to remove lubricant by wet cleaning wire drawing in the finishing process, that is, fine adjustment of the amount of lubricant adhesion, as a result, the color tone of the wire surface is numerically measured by a colorimeter and the brightness is specified in a specific range. Improving welding workability such as feedability by comprehensively managing the condition of the wire surface,
It could be stabilized.

These effects can be achieved by the coexistence effect of each composition and the combination of the arrangement and the order. The reasons for the limitations are described below.

Table 1 Comparative Example No. As shown in FIG. 10, in the case of the flux-cored wire without wrap shown in FIG. 1A, the opening width of the seam is wide, and when wet drawing is performed for the purpose of removing dry lubricant, the lubricant is discharged from the opening through the wire. Get inside. Therefore, the present inventors have searched and studied various lubricant compositions and methods that can achieve the target feedability without deteriorating the arc stability only by dry drawing that can minimize the number of steps. Is ensured, the amount of lubricant attached becomes excessive. Conversely, if the amount of adhesion is reduced, the lubricating film will not be formed stably, and the wire drawing will deteriorate due to lack of lubrication, and wire roughening and disconnection will occur frequently. It turned out to be very difficult. In addition, we examined the dry removal of excess lubricant on the surface of the dry drawn wire with a brush, buff, etc., but the amount and color tone were not stable due to unevenness of removal, and the feedability fluctuated.
Stable performance could not be obtained.

[0028]

[Table 1]

First, the joint of the flux-cored wire is illustrated.
A wire is manufactured by changing the wrap margin shown in FIG. 1 (b) and changing the wrap margin LR by adjusting the roll tightening at the time of forming, and changing the wire diameter at which wet drawing is started, that is, changing the total area reduction ratio and drawing the total wire. Hydrogen was measured. The total amount of hydrogen in the wire was determined by subjecting a sample in a graphite crucible to high-frequency melting in He gas and discharging hydrogen gas by water gas fusion-thermal conductivity method.
It was measured according to IS Z 2614. Figure 2 shows the result.
Shown in From this result, when the total area reduction rate was 80% or more, Table 1 Comparative Example No. As shown in FIGS. 10 and 11, it was found that the total hydrogen amount was high and the stabilization was not achieved when the lapping amount was less than 15%. When the lap allowance LR is set to 30% or more, Table 1 Comparative Example No. As shown in 12, the filling rate of the flux becomes small, the required amount of the flux becomes insufficient, and it becomes difficult to obtain a stable slag encapsulation and an arc. In addition, the bias of the arc is recognized, and the straightness of the wire is impaired.
Therefore, the lap cost was limited to 15 to 30%.

Further, when the lap rate is 15% or more, the total area reduction rate is 8
If it is 0% or more, the increase in the total hydrogen amount is small, and therefore, only the lower limit is limited in the present invention. However, although the upper limit of the total area reduction rate is the product diameter, when the softening treatment is not performed, the processing limit is reached and the disconnection rate increases, so that it is desirable to suppress the reduction to 97% or less from the viewpoint of productivity. Therefore, the lap fee is 15-3
For 0% flux cored wire, use 2 wax.
80% gross surface reduction using dry lubricant added to 20%
It was found that if the wire was drawn up to the above, it was possible to prevent an increase in the amount of hydrogen due to the penetration of the wet lubricant from the joint even by the wet wire drawing.

Next, the wire wrap is fixed at 25% of the wire diameter and the total area reduction rate until the wet drawing is constant at 90%. After the dry drawing, the composition and the concentration of the mixed lubricant of the wet drawing are changed and the drawing is carried out for optimal cleaning. The conditions were examined. In cleaning, it is not possible to sufficiently remove the lubricant adhering more than necessary only by passing the cleaning oil. Therefore, it is efficient to remove excess lubricant at the same time as wire drawing when passing through the hole die. However, with a cleaning agent alone, wire drawing lubricity is poor and wire roughening and wire breakage occur. Table 1 Comparative Example No. As shown in FIG. 17, the cleaning effect is small with only the oil-based lubricant, and the amount of the attached lubricant is small. Therefore, a confirmation test was conducted to find the optimum ratio by adding a cleaning agent to the wet lubricant, but the reproducibility was low.As a result of further investigation, it was found that adding a dry lubricant within the range of oil-based lubricant It has been found that the properties are improved, the color tone is stabilized with a small number of dies, and the desired amount of lubricant attached can be achieved.

That is, when a dry lubricant is added to a wet lubricant as a cleaning die drawing lubricant after dry drawing, if the dry lubricant is less than 40% by weight, Comparative Example No. 1 in Table 1 is used. As shown in FIG. 18, it takes time for the attached lubricant level to decrease and become constant, and the attached amount and color tone are not stable. On the other hand, when the dry lubricant ratio exceeds 60%, Table 1 Comparative Example No. As shown in FIG. 19, the fluidity of the wet lubricant is reduced, the lubricant does not reach the wire surface stably, and the amount of adhesion becomes unstable, and finally the lubrication is interrupted, resulting in rough and broken wires. Accordingly, the weight of the mixed lubricant is limited to 40% or more by weight of the dry lubricant, and the upper limit is limited to 60% from the viewpoint of fluidity.

The dry lubricant used in the present invention refers to one or more of high melting point wax, metal soap, MoS ₂ , WS ₂ , PTFE, and graphite. The wax mixed with the dry lubricant allows the dry lubricant to be stably brought into the hole die, prevents peeling and falling off during wire drawing, secures stable lubricant adhesion, and seals the joint to wet lubricant. Is added to prevent intrusion of the ink and to secure a stable and appropriate amount and color tone of the product after cleaning. In addition, the lubricant attached to the wire surface is kept water repellent, which is effective in preventing moisture absorption and rusting during storage. However, if the addition amount is less than 2%, the results are shown in Table 1. No effect was observed as in 15 and 2
When more than 0% is added, Table 1 Comparative Example No. As shown in Fig. 16, the amount of the lubricant brought in becomes excessive, the peeling occurs during the drawing, and the amount of adhesion at the final diameter fluctuates, and the wire becomes unstable in color tone and feedability. Therefore, in the present invention, the amount of wax added to the dry lubricant is limited to 2 to 20% by weight.
In order to further stabilize the adhesion of the dry lubricant, it is preferable to carry out a combination of a pressure roll, a rotary die, and water cooling of the die and the roll.

The wet lubricant used in the present invention is obtained by adding a detergent to an oil-based lubricant in a weight ratio of 5 to 80%.
If it is less than Table 1, Comparative Example No. As shown in FIGS. 20 and 22, cleaning is insufficient and the amount of lubricant adhering increases, resulting in low brightness, large spatter, and unstable arc. Conversely, 80% of detergent
When the above additions were made, Table 1 Comparative Example No. As shown in FIGS. 21 and 23, excessive washing resulted in a lack of a necessary amount of lubricant attached, resulting in a decrease in feedability and a failure in stable welding.

The oil-based lubricant is a liquid at room temperature and can be used as a base oil such as animal or vegetable oils, mineral oils or synthetic oils which are not deteriorated or solidified by the heat generated during drawing and do not impair the lubricating performance. For example, vegetable oils such as palm oil, rapeseed oil, coconut oil, olive oil, castor oil, etc .; animal oils such as lard, sheep oil, liver oil, etc .; mineral oils such as machine oil, turbine oil, spindle oil etc .; There are diester oil, polyalkylene glycol oil, halogenated hydrocarbon oil, silicone oil and the like.

As the cleaning agent, gas oil, light oil, kerosene, creosote oil or hydrocarbon oil having a boiling point of about 160 to 260 ° C. can be used. This is advantageous.

The color tone of the surface of the seam flux-cored wire produced by the method of the present invention has a silver-white metallic color, but the conditions at the time of wire drawing, that is, the kind, composition, temperature,
It varies depending on conditions such as viscosity and drawing die material. Therefore, the surface condition of the wire was measured with a colorimeter, and the relationship between the value and the wire quality, especially the feedability was examined.

The color tone of the wire surface is similar to the visual sense condition.
The vertical reflected light of the pulsed xenon lamp diffused light is measured under certain conditions in accordance with the D-0 method defined in ISZ 8722, and J
L ^* C ^* h conforming to L ^* a ^* b ^* color system of ISZ 8729
Expressed in color system and recorded numerically. The color tone of the wire of the present invention under various conditions and the comparative wire after being aligned and wound on a spool are shown in Test No. 1 in Table 1. As shown in FIGS. 1 to 9, it was found that there was a correlation between the amount of lubricant attached to the wire surface and the feedability.

However, since the color tone of the wire surface is silver-white of metallic luster and the variation in hue and saturation is small and the lightness L ^* corresponds best with the variation in the color tone of the wire, the lightness L ^{* of the} product wire is obtained from these results ^. Is specified as 40-60,
By adjusting the drawing conditions so as to fall within this numerical range, a stable color tone and feedability could be obtained.

When the lightness L ^* is less than 40, the amount of lubricant attached to the wire surface is large, and the slip ratio of the wire feed roll during welding is high, and stable welding workability cannot be obtained. Conversely, lightness L
^{If *} exceeds 60, the amount of lubricant attached to the wire surface will be insufficient, the feed resistance will be high, and the feed will be unstable. In extreme cases, the wire will buckle and welding will not be possible.

Further, depending on the use conditions, a small amount of lubricating oil is applied in the final step of wire production, for example, in the final die for wire drawing or spool winding, so that the feeding resistance is lower than in the case of using only wax or the like and solid lubricant. However, the feedability under severe conditions is further stabilized. For example, when welding is started in a low temperature environment such as winter, the feed resistance is generally high, the bent state of the conduit cable is large, and the feed may be unstable if the feed resistance is large. However, applying oil has the effect of lowering the feed resistance and shortening the time until the arc is stabilized. An oily lubricating oil that is liquid at normal temperature is used as the application oil.

[0042]

EXAMPLES The effects of the present invention will be specifically described below with reference to examples. Wet drawing was performed by changing the wrap width and the total area reduction rate according to the process shown in FIG. 3, and the amount of wax added was adjusted. Wire diameter 1.2, 1.6 mm, YFW-C50DR flux contained in JISZ 3313. A wire (filling rate: 15%) was prototyped. The test wire was filled with the filling flux at a predetermined filling rate, dry-drawn to each reduction area before wet-drawing, and then wet-drawn to the product diameter. Further, a winding test was performed on a spool in the alignment winding process.

The color tone is determined by a colorimeter (MINOLTA CR-) designed in accordance with JIS Z 8722 D-0 method.
300) was placed perpendicular to the winding wire surface, and the wire surface aligned and wound on a spool was measured by shifting the wire surface by 5 mm in the direction shown in FIG.
This was rotated at 90 ° and evaluated at an average value measured at four points.

The welding workability and the feedability were as follows: using a conduit cable 6 having a length of 6 m with the apparatus shown in FIG. Was welded downward on the steel plate 9.

[0045]

[Table 2]

The wire feed of the sheet resistance feeding resistors R a reaction force of the pushing force and the conduit cable feed roll during welding in the above condition, the peripheral velocity V _R and the wire of the feed speed V _W of the feed roll The slip ratio SL was calculated from the following equation and evaluated. In the actual measurement, as shown in FIG. 5, a load is applied in a direction in which the wire 2 retreats due to the reaction force of the wire feed roll 4, but the force generated at this time is supplied by the load cell 5 to the feed resistance R.
Was measured. The slip ratio SL at the wire feeding roll portion is obtained by measuring the peripheral speed (V _R ) of the feeding roll 4 and the wire feeding speed (V _W ) by the measuring roll 3 installed just before the entrance of the feeding roll. It was determined by the following equation. Slip ratio _{SL (%) = (V R} -V W) · 100 / V R

The evaluation of the feeding performance was such that the feeding resistance R was 60 N or less,
It was determined to be good when the slip ratio SL was 10% or less. The welding was performed by cooling the welding torch and the steel plate at 3 minutes / time, and the feed resistance R and the slip ratio SL were measured to obtain an average value. Regarding the stability of the arc and the spatter, in the sensitivity test, ○ was evaluated as being equal to or higher than that of a commercially available wire of the same type, Δ was evaluated as being slightly inferior, and × was evaluated as being considerably inferior. The results are summarized in Table 1. In Table 1, Test No. 1 to 9 are Examples of the present invention, Test Nos. 10 to 23 are comparative examples.

Test No. The samples Nos. 1 to 9 had very satisfactory results in that the brightness of the wire surface was stable, the slip ratio and the feeding resistance during welding were low, and the arc was stable. In each case, the amount of diffusible hydrogen was 8 mL / 100 g or less of the deposited metal.

No. Nos. 10 and 11 have a very high diffusible hydrogen content when the lap ratio is smaller than the range of the present invention.
No. 10 had many pits. No. 11 had groove-like defects and pits on the surface of the weld bead. No. In No. 12, when the lap ratio exceeds the range of the present invention, the arc is coarse, the slag encapsulation is not stable, and the bead appearance is inferior. No. 13,14
In each of the cases where the total area reduction rate was less than the lower limit, the diffusible hydrogen content was high and groove-like welding defects were observed in all cases. No. 15,1
No. 6 indicates that the amount of wax added in the dry lubricant is out of the range of the present invention and N
o. In No. 15, the lubricating agent was not stable, the lubricant film was interrupted, and the drawing was liable to be interrupted, and the amount of the lubricant supplied on the wire surface was insufficient, so that the brightness exceeded the range of the present invention. Conversely, No. 16 had a large amount of adhesion, the lightness was lower than the range of the present invention, and the feeding of the wire was unstable, and stable welding could not be performed. N
o. Nos. 17, 18, and 19 are cases where the amount of dry lubricant added to the wet early lubricant is out of the range of the present invention. Nos. 17 and 18 were not stable due to insufficient cleaning, and had low brightness and unstable wire feeding. No. In No. 19, the fluidity of the initial wet-type lubricant was lowered, stable cleaning could not be performed, and welding arc and feedability were unstable. No. Nos. 20 and 22 are cases where the amount of the detergent added in the wet lubricant is less than the range of the present invention. In all cases, the cleaning is insufficient, the amount of the lubricant attached is large, the brightness falls below the range of the present invention, and the arc and the feeding property are unstable. there were. No. Reference numerals 21 and 23 indicate that when the amount of the detergent added in the wet lubricant exceeds the range of the present invention and the amount of the lubricating oil added is small, the amount of the lubricant exceeds the range of the present invention due to excessive cleaning, the amount of the adhered lubricant is small, and Feeding was unstable.

In the present embodiment, JIS Z 3313 mild steel,
490 N / mm ² YFW-C50RD for tensile strength steel is illustrated, but other steel types and shielding gas, and JIS
Z3318, Mo, Cr-Mo steel, JIS Z3319
For electrogas arc welding, JIS Z 3320 for weathering steel, JIS Z 3323 stainless steel, JISZ 3
It is also applicable to flux cored wires for welding with seams of other steel types such as 326 hardfacing.

[0051]

As described above in detail, it is possible to control the amount of lubricant supplied and to control the color tone of the wire surface by the wet drawing of the flux-cored wire with seams in the manufacturing method according to the present invention. Flux-cored wire for arc welding that has an excellent effect that enables stable arc welding for a long time even when welding is performed under severe bending conditions and high current conditions using a soft and long conduit cable Can be provided.

[Brief description of the drawings]

FIG. 1 is a diagram showing a cross section of a flux-cored wire.

FIG. 2 is a diagram showing a relationship between a lap ratio, a total area reduction ratio, and a total hydrogen amount.

FIG. 3 is a view showing a manufacturing process of a flux-cored wire.

FIG. 4 is a diagram showing a procedure for measuring the color tone of the wire surface.

FIG. 5 is a view showing a welding apparatus used in the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wire spool conduit cable 2 Welding wire 3 Measuring roll 4 Feeding roll 5 Load cell 6 6m conduit cable 7 Conduit cable bending part 8 Welding torch 9 Welding steel plate 10 Turntable

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Masaki Abe 3-5-4 Tsukiji, Chuo-ku, Tokyo Nippon Steel Welding Industry Co., Ltd. F-term (reference) 4E084 AA44 CA38 DA09 HA12 4E096 EA02 EA12 EA16 EA24 GA03 HA01 HA02 JA12 JA13 KA01

Claims (5)

[Claims] In a flux-cored wire having a seam, the seam wrap margin length of the wire sheath is 15 to 30% of the wire diameter, and the lightness L ^{* of the} wire surface is 40 to 6
0. A flux cored wire for arc welding, further comprising a solid lubricant on the surface of the wire. 2. The flux cored wire for arc welding according to claim 1, wherein an oily lubricant is applied on the solid lubricant on the surface of the wire. 3. A method of manufacturing a flux-cored wire having a seam, wherein a flux-cored wire having a length of 15-30% of a wire diameter filled with the flux is used as a wire, and the wire is dry-processed. A method for producing a flux-cored wire for arc welding, comprising drawing a wire in a total area reduction of 80% or more using a lubricant, and then drawing it wet using a hole die. 4. The dry lubricant contains 2 to 20% by weight of a high melting point wax by weight, and the wet lubricant contains 5 to 80% by weight of a detergent to an oily lubricant. Of manufacturing flux-cored wire for arc welding. 5. The method for producing a flux-cored wire for arc welding according to claim 4, wherein the first die lubricant for wet drawing includes a wet lubricant containing 40 to 60% by weight of a dry lubricant. .