JP2000237894A - Flux-cored wire for gas shielded arc welding and method for producing the same - Google Patents

Abstract

(57) [Summary] [Problem] Even when a long conduit cable is bent in an S-shape or a J-shape during welding, slip on a wire feeding roller is small and friction in a conduit tube is obtained. Provided are a flux-cored wire for gas shielded arc welding having extremely good wire feedability such as low resistance, and a method for producing the same. SOLUTION: The flux cored wire for gas shielded arc welding has a tensile strength of 450 to 600 N per sectional area.
/ Mm ² , wire surface roughness Ra is 0.08 to 0.22μ
at least one type of molybdenum disulfide or tungsten disulfide per 10 kg of wire is applied to the uneven surface having a diameter of 0.01 m.
It is characterized by having up to 0.05 g. Further, in the method of manufacturing a flux-cored wire for gas shielded arc welding, one or more types of molybdenum disulfide or tungsten disulfide are drawn after the primary annealing, after secondary drawing, secondary annealing, pickling and plating. Tertiary wire drawing with a lubricant containing, followed by quaternary wire drawing by wet wire drawing.

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 gas-shielded arc welding and a method for producing the same, and more particularly, to a flux-cored wire for gas-shielded arc welding having excellent wire feedability during welding and its production. About the method.

[0002]

2. Description of the Related Art A general method of manufacturing a flux-cored wire for gas shielded arc welding, particularly a seamless flux-cored wire, is as shown in FIG. Wire drawing with roller dies or hole dies (primary wire drawing),
(B) annealing step, (c) pickling step, (d) plating step,
(E) wire drawing process to the final size diameter (finish wire drawing),
(F) It is performed by a winding step of loading a spool or a pail pack. Flux-cored wires for gas shielded arc welding (hereinafter referred to as flux-cored wires) manufactured by these methods have been used for wire feeding along with the automation of welding, the spread of welding robots, the lengthening of conduit cables, and the like. There is a growing demand for improved performance.

[0003] Conventionally, in order to improve the wire feedability, a small amount of an animal or vegetable oil or a mineral oil alone or a mixed lubricant thereof, as typified by Japanese Patent Publication No. 50-3256, is generally used for the wire. The lubricant is applied to the surface of the wire in the finishing wire drawing step (e), and the lubricant improves the wire feedability. In addition, length 6-20m
In the case of using a long conduit cable and welding at a narrow site, the conduit cable is often bent into an S-shape or a J-shape. In this case, the contact friction portion between the conduit tube in the conduit cable and the wire passing through the inside increases, so that the feeding resistance increases, and the welding wire slips at the wire feeding roller to deteriorate the wire feeding property. . Therefore, Japanese Patent Application Laid-Open
No. 27198, the average diameter of the wire is 5
A method of performing shot blasting using a shot of 0 to 750 μm to form a concave portion, and thereafter applying a lubricating oil, or a porous plating having a porosity of 5 to 50% as described in Japanese Patent Publication No. 1-15356. A coating is disclosed in which the coating layer is coated with a lubricating oil.

[0004] However, in the above-mentioned Japanese Patent Application Laid-Open No. 61-27198, there is a problem in the continuous workability while the wire surface is formed into a predetermined uneven shape by shot blasting. Further, since the surface of the wire is work-hardened, the frictional resistance increases in the bent conduit tube. On the other hand, in Japanese Patent Publication No. 1-15356, it is difficult to control plating coating, and the manufacturing process is complicated. In addition, since the surface of the wire base is flat and the plating layer is porous, good wire feeding performance is determined by the balance between the feeding force of the wire feeding roller and the frictional resistance in the conduit tube. Cannot be maintained.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a wire feeding roller which has a small slip and a conduit even when a long conduit cable is bent in an S-shape or a J-shape during welding. An object of the present invention is to provide a flux-cored wire for gas shielded arc welding having extremely good wire feedability, such as low frictional resistance in a tube, and a method for producing the same.

[0006]

The gist of the present invention is as follows: (1) a gas-shielded arc welding flux-cored wire having a tensile strength per cross-sectional area of 450 to 600 N / mm ² ;
A flux-shielded wire for gas shielded arc welding, comprising 0.01 to 0.05 g of one or more of molybdenum disulfide or tungsten disulfide per 10 kg of wire on a surface having a wire surface roughness Ra of 0.08 to 0.22 μm. (2) In the method of manufacturing a flux-cored wire for gas shielded arc welding, the wire after primary annealing is subjected to secondary drawing, then secondary annealing, pickling, plating and then molybdenum disulfide or tungsten disulfide. Third wire drawing with a lubricant containing more than one kind, followed by wet wire drawing and fourth wire drawing.

In addition, the wire surface roughness Ra after the secondary wire drawing is 0.40 to 0.80 μm, and the total area reduction rate in the tertiary and quaternary wire after plating is 80% or less. A method for manufacturing a flux-cored wire for gas shielded arc welding. The wire surface roughness R according to the present invention
“a” refers to a value measured in the wire longitudinal direction according to JIS B0601. The area reduction rate is represented by the following equation. Reduction area = {1− (wire cross-sectional area after processing / wire cross-sectional area before processing)} × 100

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing a wire feeding step. The flux-cored wire 1 is set in a wire feeding device (not shown) and is driven by a feeding motor (not shown) to drive the flat pressure feeding roller 2 and the V-groove feeding roller of the wire feeding unit. 3 and sequentially fed from a conduit cable 4 through a welding torch 5 to a weld. At this time, the flux-cored wire 1 is pressed by the flat pressure feeding roller 2 and the V-groove feeding roller 3 of the wire feeding unit, and the flux-cored wire 1 is moved into the V-groove feeding roller 3 by its vertical load. Although it tries to enter, the frictional force due to the contact with the V-grooved roller 3 acts to produce the feeding force. Further, since the wire passes through a conduit tube (not shown) in the conduit cable 4 of, for example, 6 to 20 m, the frictional resistance changes depending on the rigidity of the flux-cored wire 1, the state of adhesion of the lubricant on the wire surface, and the shape of the wire surface. The delivery is variable.

By reducing the rigidity (tensile strength) of the wire and appropriately setting the surface roughness Ra of the wire to at least one type of molybdenum disulfide or tungsten disulfide, a long conduit cable can be formed into an S-shaped cable. Alternatively, even in the case where the wire is used by being bent into a J-shape, the wire feeding property is extremely improved because the slip in the wire feeding roller and the frictional resistance in the conduit tube are small. These effects can be obtained by the coexistence effect and synergistic effect of at least one of molybdenum disulfide or tungsten disulfide, and the tensile strength of the wire, the surface roughness Ra of the wire, and the reasons for these limitations are described below. .

By setting the tensile strength per flux-cored wire cross-sectional area to 450 to 600 N / mm ² , it can flexibly follow even in a bent conduit tube and reduce frictional resistance. However, when the tensile strength per flux cross-sectional area is less than 450 N / mm ² , the flux-cored wire may buckle in the conduit tube. Conversely, if it exceeds 600 N / mm ² , the frictional resistance particularly in the bent conduit tube becomes large, the feedability becomes poor, and the arc becomes unstable.

[0011] The wire surface roughness Ra is 0.08 to 0.22
By setting it to μm, the flux-cored wire sent to the wire feeding roller portion can be fed without slipping due to the frictional force acting on the V-groove feeding roller and the flat roller. When the wire surface roughness Ra is less than 0.08 μm, the frictional force between the V-groove feeding roller and the flat roller is small, and the flux-cored wire slips and the arc becomes unstable. Conversely, if the wire surface roughness Ra exceeds 0.22 μm, the frictional resistance in the conduit tube increases, resulting in poor wire feedability and unstable arcing.

At least one of molybdenum disulfide or tungsten disulfide is held in the concave portion of the wire surface at 0.01 to 0.05 g per 10 kg of the wire to further reduce the frictional resistance in the bent conduit tube. . Molybdenum disulfide or tungsten disulfide
If the number of the seeds is less than 0.01 g per 10 kg of the wire, the friction resistance increases in the conduit tube bent at the time of wire feeding, and the arc becomes unstable. Conversely, 0.
If it exceeds 0.05 g, the flux-cored wire slips at the wire feeding roller portion during welding, and the arc becomes unstable.

FIG. 2 shows an example of a manufacturing process of the flux-cored wire of the present invention. Step of drawing the flux filled tube after flux filling to a diameter of 3 to 6 mm with a roller die or hole die (primary drawing), primary annealing step, pickling step, secondary drawing step, secondary annealing step, pickling Process,
A plating step, a coating tertiary drawing step of drawing using at least one of molybdenum disulfide or tungsten disulfide,
Wire drawing process to the final size diameter (finish fourth wire drawing),
(10) By manufacturing by a winding process of winding on a spool or loading into a pail pack, the wire tensile strength is low, the wire surface roughness Ra is moderate, and one or more types of molybdenum disulfide or tungsten disulfide are moderate. Even when a long conduit cable is used by bending it into an S-shape or J-shape, the wire feeding roller has little slip resistance and friction resistance inside the conduit tube, so that the wire feeding property is small. A very good wire can be manufactured.

[0014] Since the total area reduction in tertiary and quaternary wire drawing after the secondary annealing and plating is 80% or less, the wire tensile strength of the product can be reduced. Can flexibly follow, and the frictional resistance can be reduced. Do not do secondary annealing,
Total reduction of area in tertiary and quaternary wire after plating is 80
%, The tensile strength of the wire increases, and particularly the frictional resistance in the bent conduit tube increases, resulting in poor feedability and unstable arcing. The condition of the secondary annealing is not particularly limited, but is preferably 650 ° C. or more and holding time 2 minutes or more in consideration of the wire component and the degree of work hardening. Further, the lower limit of the total area reduction after plating is preferably 30% or more in order to adjust the wire surface roughness Ra and the wire tensile strength at the product diameter.

The wire surface roughness Ra after the secondary annealing of the flux-annealed tube subjected to the primary annealing is 0.40 to 0.80 μm.
Since the total area reduction rate in the tertiary and quaternary wire drawing after plating is less than 80%, the wire surface roughness Ra of the product becomes moderate, and the wire sent to the wire feeding roller portion has a V-groove. The frictional force acts on the feeding roller and the flat roller, and the roller can be fed without slipping. If the wire surface roughness Ra after the secondary drawing is less than 0.4 μm, or if the total surface reduction rate in the wire drawing after plating exceeds 80%, the wire surface roughness Ra of the product is 0.08 μm. And the frictional force between the V-groove feed roller and the flat roller is small, and the flux-cored wire slips and the arc becomes unstable.

Furthermore, in the third application drawing step of drawing using a lubricant containing at least one of molybdenum disulfide or tungsten disulfide, the coating amount of one or more types of molybdenum disulfide or tungsten disulfide is reduced. Become,
In particular, the frictional resistance in the bent conduit tube becomes large, the feeding property becomes poor, and the arc becomes unstable.
Conversely, wire surface roughness Ra after secondary drawing of a wire strand
Exceeds 0.80 μm, the dies are roughened in the final quaternary wire drawing process, causing scratches on the wire surface, or a wire drawing using a lubricant containing at least one of molybdenum disulfide or tungsten disulfide. In the tertiary drawing step, one or more of molybdenum disulfide or tungsten disulfide is applied too much, and the flux-cored wire slips at the wire feed roller during welding, resulting in an unstable arc. Further, when the wire surface roughness Ra of the product wire exceeds 0.22 μm, the frictional resistance in the conduit tube increases, the wire feedability becomes poor, and the arc becomes unstable.

The wire surface roughness Ra after the secondary drawing of the wire wire may be performed by using a roller die having a groove having an appropriate roughness or by dry-drawing. If Ra is in the range of 0.40 to 0.80 μm, it is not necessary to forcibly impart roughness. In addition, the area reduction rate of the wire drawing in the tertiary wire drawing step is preferably 5 to 30%, and the lubricant may be molybdenum disulfide or tungsten disulfide.
10% to 50% or more of the seeds, other waxes, fluorine resin,
A lubricant mixed with an organic or inorganic powder such as carbonated oil or a lubricant mixed with grease, animal and vegetable oil, mineral oil or synthetic oil-based fat or oil is used. The wire element referred to in the present invention is a flux-filled tube after flux filling, which is subjected to primary drawing, primary annealing and pickling to 3 to 6 mm, or primary annealing and pickling without primary drawing, or It refers to one that has undergone only primary annealing.

[0018]

The present invention will be described in more detail with reference to the following examples. First, as for the wire strand, a filling tube of a seamless flux-cored wire (flux filling rate: 14%) of YFG-C50DR specified in JIS Z3313 is primarily drawn to each wire diameter shown in Table 2 to perform primary annealing and acid annealing. A washed wire was used. Table 1 shows the components of the flux-cored wire used at this time.

[0019]

[Table 1]

The wire strand is dry-drawn to a wire diameter shown in Table 1 in a secondary drawing step shown in FIG. 2 to impart a wire surface roughness Ra, and subjected to secondary annealing (annealing temperature 650 to 750).
Temperature, holding time 4 to 10 min), after pickling and plating, one or more types of molybdenum disulfide or tungsten disulfide were mixed with synthetic wax and metal soap at different mixing ratios in the tertiary wire drawing step. Using a solid lubricant, apply a tertiary wire with a hole die, finish the quaternary wire drawing process with wet wire drawing, and skin pass wire drawing with the product diameter shown in Table 2 and take up a 20 kg spool wire wire in the winding process (10). And Investigation of wire feedability was 6 m with the device shown in FIG.
Using a conduit cable 4 having a length, the conduit cable 4 shown in FIG.
Under the welding conditions shown in Table 3, 10 kg of each wire was welded.

[0021]

[Table 2]

[0022]

[Table 3]

The wire feedability was examined by measuring the armature current of the wire feed motor. Note that the armature current is 3.5
If it exceeds A, the arc length changes and the arc becomes unstable. Also, the wire slip at the wire feed roller is
The peripheral speed (T) of the wire feed roller and the wire speed (W) at the outlet of the wire feed roller were measured, and the slip ratio was calculated and examined using the following equation. If the wire slip rate exceeds 5%,
The arc becomes unstable due to irregularities in the wire feeding speed due to irregularities in the wire feeding speed. Slip ratio = (T−W) / T × 100 The results are shown in Table 2.

In Table 2, Test No. 1 to 6 are examples of the present invention and test Nos. 7-14 are comparative examples. Test No. of the present invention example. Nos. 1 to 6 are ones of molybdenum disulfide or tungsten disulfide after secondary drawing of the wire after primary annealing to impart an appropriate surface roughness Ra, secondary annealing, pickling and plating. Applying tertiary wire drawing with a lubricant containing the above, finishing quaternary wire drawing, and the total area reduction rate after plating is 80% or less, tensile strength of the product wire, wire surface roughness Ra and molybdenum disulfide or Since the content of at least one kind of tungsten disulfide is appropriate, even if a long conduit cable is bent and welded, the wire slip ratio at the wire feeding roller section is small, and the friction resistance in the conduit tube is small. The armature current was low and the arc was stable, which was a very satisfactory result.

Test No. in the comparative examples. In No. 7, the wire surface roughness Ra after the secondary drawing is low, so that the wire surface roughness Ra of the product wire is low, the frictional force between the V-groove feed roller and the flat roller is increased, and the slip ratio is reduced. High and the arc became unstable. Test No. No. 8 has a low wire surface roughness Ra after the secondary drawing, so the molybdenum disulfide content is low in the concave portion of the product wire, the wire friction resistance is large, the armature current is high, and the wire feedability is poor. The arc became unstable.

Test No. In No. 9, since the wire surface roughness Ra after the secondary drawing was high, the die was roughened in the finishing quaternary drawing step, and the wire surface was damaged, so the trial production was stopped. Test N
o. No. 10 has high content of molybdenum disulfide and tungsten disulfide in the concave portion of the product wire because the wire surface roughness Ra after the secondary drawing is high, and the frictional force to the V-groove feed roller and the flat type roller is high. Became small, the slip ratio was high, and the arc became unstable.

Test No. No. 11 has a high wire surface roughness Ra after the secondary drawing, so the wire surface roughness R of the product wire is high.
a was high, the wire frictional resistance was large, the armature current was high, the wire feedability was poor, and the arc was unstable. Test No. In No. 12, the total surface reduction rate after plating is high, so the wire surface roughness Ra of the product wire is low, the frictional force on the V-groove feed roller and the flat type roller is small, the slip rate is high, and the arc is low. It became unstable.

Test No. In No. 13, since the total area reduction rate after plating was high, the wire tensile strength was high, the wire frictional resistance was large, the armature current was high, the wire feedability was poor, and the arc was unstable. Test No. 14 is
The wire buckled in the conduit tube due to low total area reduction after plating and low wire tensile strength.

[0029]

As described above in detail, according to the flux-cored wire for gas shielded arc welding of the present invention and the method for manufacturing the same, a long conduit cable is welded during welding.
Even when used by bending into a letter or J shape,
The feeding force of the wire feeding roller is obtained, and welding with a small frictional resistance in the conduit tube and stable arc can be performed.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing a wire feeding step.

FIG. 2 is a schematic view of a flux-cored wire production line for gas shielded arc welding according to the present invention.

FIG. 3 is a diagram showing a loop portion of a conduit cable used in an embodiment of the present invention.

FIG. 4 is a schematic view of a conventional flux-cored wire manufacturing line for gas shielded arc welding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flux-cored wire 2 Flat pressure feed roller 3 Feed roller with V groove 4 Conduit cable 5 Welding torch

Claims (4)

[Claims] The tensile strength per flux cross-section wire for gas shielded arc welding is 450 to 600 N /
mm ² , wire surface roughness Ra is 0.08 to 0.22 μm
At least one of molybdenum disulfide or tungsten disulfide per 10 kg of wire is applied to a surface of 0.01 to 0.0
A flux-cored wire for gas shielded arc welding, comprising 5 g. 2. A method for producing a flux-cored wire for gas shielded arc welding, comprising: a step of secondary drawing of a wire after primary annealing, followed by secondary annealing, pickling, plating, and then molybdenum disulfide or tungsten disulfide. A method for producing a flux-cored wire for gas shielded arc welding, comprising tertiary drawing with a lubricant containing at least one of the following, followed by wet drawing and finishing quaternary drawing. 3. The flux-cored wire for gas shielded arc welding according to claim 2, wherein the wire surface roughness Ra after secondary drawing of the wire is 0.40 to 0.80 μm. Production method. 4. The tertiary and quaternary wire drawn after plating has a total area reduction rate of 80% or less.
A method for producing a flux-cored wire for gas shielded arc welding according to claim 3.