JPH10118710A - Diamond die for drawing flux cored wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diamond die for wire drawing without generating disconnections and flaws on the wire surface in high speed drawing for a thin diameter of flux cored seamless wire having high filing factor and iron powder ratio. SOLUTION: The diamond die is specified to provide with the bearing inner diameter (d) of 0.78-5.0mm and the reduction angle γ of 4-10 deg., and another one is further provide with the approach angle β of 4-14 deg., the bearing length of 0.20-0.50mm to the bearing inner diameter (d) and the relief angle θ of 20-60 deg.. These are used for drawing the flux cored wire filled, by whole wt. ratio of flux cored wire, 12-25% flux containing, by wt., 10-80% iron powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond die for wire drawing of a flux-cored wire for welding, and more particularly to a flux filling ratio (weight ratio of the flux to the total weight of the flux-cored wire) and an iron powder ratio (iron in the flux). (Weight ratio of powder) and a diamond die for wire drawing of a flux-cored wire having a small diameter and no seams.

[0002]

2. Description of the Related Art In recent years, automation of welding and labor saving have been promoted. As a welding wire used for such welding, a flux-containing wire having characteristics such as high efficiency welding, less spatter, and a beautiful bead shape is used. Wire is by far the best, and the demand for flux cored wires for semi-automatic and fully automatic welding is increasing. Therefore, a diamond die capable of high-speed drawing has been developed for the purpose of improving the productivity of a flux-cored wire.
-328124.

However, in recent years, welding has been further automated, and in welding such as shipbuilding and tank construction, a welding machine having a narrow groove and capable of high-speed welding has been developed, and the welding efficiency has been significantly improved.

[0004] The flux-cored wires used for these become flux components mainly composed of metal powder containing 10% or more of iron powder in order to increase the amount of deposited metal, and the flux filling rate is 12 in order to increase the deposition rate. %. The wire diameter used is 0.8 ~
The diameter has been reduced to 1.6 mm.

[0005] A general method of manufacturing a seamless flux-cored wire is as described in Japanese Patent Publication No. 45-30937, in which a steel pipe having an outer diameter of about 13 mm is vibration-filled with a flux, and then a primary drawing is performed. After processing to a diameter of 3 mm, softening annealing and copper plating (sometimes omitted) are performed, and further, drawing to a desired diameter of 0.8 to 1.6 mm is performed by die drawing. The primary wire drawing is reduced by die wire drawing and wire drawing by a three-roll mill (hereinafter, referred to as three-roll wire drawing).
The three-roll wire drawing is a method of driving three small-diameter rolls to reduce the diameter. Although the efficiency is higher than that of the die drawing, it is difficult to draw the wire to a small diameter.

[0006] The secondary drawing of the flux-cored wire is reduced in diameter by die drawing. However, as the diameter becomes smaller, the thickness of the outer shell material becomes thinner. The ratio is reduced, and the processing force of the flux and the frictional force with the die all act as a pulling force on the outer material, so that the wire is easily broken.

FIG. 1 shows a thickness distribution of an L section (length section) of a flux-cored wire in which a flux 2 is filled in a sheath material 1. Such a thickness distribution can be obtained by L-section polishing or X-ray photography. A maximum thickness a and a minimum thickness b within a predetermined L section length are measured, and a value obtained by dividing the maximum thickness by the minimum thickness is defined as a P value. When the P value exceeds 1.5, it is easily broken. It is considered that the reason is that the processing strain is locally concentrated on the minimum thickness portion and the ductility is reduced.

[0008] When a flux-cored wire having a high filling rate and a high iron powder rate is drawn by a die, the P value increases and the wire is easily broken. The reason is that the flux density is increased by three-roll wire drawing, and the outer shell material softened by subsequent annealing is easily stretched by secondary wire drawing. Therefore, in the initial die drawing of secondary wire drawing, it is shown in FIG. As described above, the portion where the fluidity of the flux is poor produces a portion having an extremely low flux density or voids 3. In the subsequent die drawing in which the flux density starts to increase, as shown in FIG. 3, the thickness of the outer shell material 1 increases at the portion where the flux density is low or at the gap 3, and the outer shell material 1 increases at the portion where the flux density is high. Becomes thinner. As a result, fluctuations in the thickness of the shell material hinder the flowability of the flux, the iron powder mainly forms a lump (hereinafter, referred to as a cluster), digs into the shell, and significantly reduces the ductility of the shell. The value becomes large, the wire is easily broken, and the wire surface is easily scratched.

When the wire is broken, the higher the wire drawing speed, the greater the number of dies coming out of the broken wire, so the number of times that the wire needs to be passed through the die again increases. In order to pass through the dies, it is necessary to make the tip of the wire thinner for each die, which takes a long time.

It has been empirically found that the higher the drawing speed, the more easily the wire breaks. For the above reasons, the wire drawing speed of the wire that is easily broken is 20 to 70% of the normal wire drawing speed.
They also have to slow down.

As described above, the demand for a fine-diameter flux-cored wire having a high flux filling rate and a high iron powder rate tends to increase, and in order to supply a large quantity of high-quality wires, prevention of disconnection during wire drawing is a major issue. .

[0012]

DISCLOSURE OF THE INVENTION The present invention relates to a wire drawing of a small-diameter flux-sealed seamless wire having a high flux filling rate and a high iron powder rate. An object of the present invention is to provide a flux-cored diamond die for wire drawing with good productivity.

[0013]

Means for Solving the Problems The present inventors have studied various shapes of diamond dies used for secondary drawing in order to achieve the above object, and found that the reduction angle of the diamond dies can be made smaller than before. As a result, the flux density hardly decreases in the secondary drawing after annealing.
It was found that the value did not increase, and no breaking occurred even at high speed drawing.

That is, the gist of the present invention is as follows: (1) A diamond die for flux-cored wire drawing, characterized in that a bearing inner diameter d is 0.78 to 5.0 mm and a reduction angle γ is 4 to 10 °. .

(2) Approach angle β4 to 14 °, bearing length 0.20 to 0.8 with respect to bearing inner diameter d
The diamond die for flux-cored wire drawing according to the above (1), wherein 0 dmm and the relief angle θ are 20 to 60 °.

(3) Bearing inner diameter d 0.78 to 5.0
mm, and the bearing length is set to 0.
20 ~ 0.80dmm, reduction angle γ4 ~ 10
{Circle around (1)} A diamond die for flux-cored wire drawing, wherein the arc radius of the die entrance is R 0.8 to 2.0 mm and the relief angle θ is 20 to 60 °.

(4) A flux containing 10 to 80% of iron powder in a weight ratio of 12 to 12 in a total weight ratio of the flux-cored wire.
The diamond die for wire drawing of a flux-cored wire according to any one of the above (1), (2) and (3), which is used for wire-drawing of a flux-cored wire filled with 25%. .

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.

FIG. 4 shows a cross-sectional shape of the diamond die. A is a bell portion having a bell angle α, B is an approach portion having an approach angle β, C is a reduction portion having a reduction angle γ,
D indicates a bearing portion having a bearing diameter d, and E indicates a relief portion having a relief angle θ. A and B are die entrances for allowing wires and lubricant to easily enter the dies, C and D are wire drawing sections for processing by contacting the wires, and E is a lubricating fluid or a modified product (oxidation in the lubricating fluid). Objects and carbides,
This is a die exit for discharging oxides, plated metals, and the like peeled off from the wire surface.

First, if the reduction angle γ of the die is set to 10 ° or less, the component of the die reaction force in the radial direction of the wire is increased, so that the flux is rolled, and it is easy to extend in the axial direction of the wire. It is possible to perform wire drawing without disconnection without increasing the P value. However, when the angle is less than 4 °, the contact length between the wire and the diamond becomes long, and the lubrication becomes insufficient, so that the surface of the wire is easily scratched. In addition, the amount of diamond used increases, and the production cost increases, which is not desirable.

The inner diameter d of the bearing is arbitrarily selected depending on the outer diameter of the wire after the primary drawing and the final finished diameter. In the present invention, the inner diameter d is 0.78 to less than the outer diameter of the wire after the three-roll drawing and the minimum finished diameter. It was 5.0 mm.

If the approach angle β exceeds 14 °, the amount of lubricant brought in decreases, the surface damage of the wire due to the roughened die increases, the pulling force increases, and the wire breaks easily. In order to obtain the entrance die diameter required for bringing in the agent, the length of the die is increased, and the cost of the die is undesirably increased. For the above reasons, the approach angle is set to 4 to 14 °.

If the bearing length is less than 0.20 dmm with respect to the inner diameter d of the bearing, the finished outer diameter of the wire becomes unstable, and if it exceeds 0.80 dmm, the lubricating material is brought in poorly. It causes wire surface scratches due to roughness. From the above, the bearing length is 0.
20d to 0.80dmm.

If the relief angle θ is less than 20 °, the dischargeability of the lubricant deteriorates, the die is roughened, and the wire surface is easily scratched. If it exceeds 60 °, the strength of the bearing is reduced. It is easy to be damaged. For the above reasons, the relief angle θ is set to 20 to 60 °.

FIG. 5 shows a modification of the shape of the diamond die. In this case, the die entrances of A and B in FIG. This radius R is 0.8 to 2.0
mm, the same effect as the approach angle β4 to 14 ° in FIG. 4 can be obtained. That is, the arc radius R at the die entrance
Exceeds 2.0 mm, the length of the die increases to obtain the entrance die diameter required for bringing in the lubricant, the die cost increases, and if it is less than 0.8 mm, the amount of the lubricant brought in is small. This is not preferable because the wire surface damage due to the roughened die increases, the pulling force increases, and the wire is easily broken.

Although the die discharge portion in FIGS. 4 and 5 has only a relief angle, this portion may be divided into a back relief angle and an exit angle. In this case, there is no problem with the conventionally used back relief angle of 5 to 35 ° and the exit angle of 35 to 100 °.

In the present invention, in order to improve the welding efficiency by increasing the amount of the deposited metal, the flux contains at least 10% by weight of iron powder and at least 12% by weight of the total weight of the wire. It is necessary. However, if the amount of iron powder in the flux exceeds 80% and the filling ratio exceeds 25%, the wire breakage will occur even if the wire is drawn using the diamond die of the present invention.

[0028]

[Example] Outer diameter 12-18mm, wall thickness 1.5-2.0m
m steel pipe (JIS G3445 STKM11A)
After granulating, drying and sizing with water glass, various fluxes having different iron powder ratios are vibratory filled to a filling ratio of 12 to 25%, and are primarily drawn to an outer diameter of 3.2 mm by 3 roll drawing and after annealing , Copper plated. Thereafter, continuous drawing was performed at a final drawing speed of 1000 mpm using 16 dies to a product diameter of 1.2 mm in outer diameter. The dies used were diamond dies prototyped in various shapes and sizes shown in Table 1, and the reduction in area of each die was 6 to 13%. As a lubricant at the time of wire drawing, a commercially available emulsion type product mainly composed of an ester, a fatty acid, a metal soap and an anionic activator was used.

The die shape in each test was determined only for the bearing inner diameter d according to the diameter reduction ratio of the wire, and the other 16 were fixed.

The amount of trial production in each test was 1 ton, and the presence or absence of breakage during wire drawing, the presence or absence of wire surface flaws, and the P value after completion of die drawing were measured. Table 1 summarizes these results.
Shown in

[0031]

[Table 1] No. 1 in Table 1. 1 to No. No. 8 is an example of the present invention; 9-N
o. 19 is a comparative example.

No. 1 of the present invention. 1 to No. No. 8 shows that even when a flux-cored wire having an iron powder rate of 10 to 80% and a filling rate of 12 to 25% is drawn, the P value is 1.5 or less, and the wire breakage or the wire surface flaws even when the final drawing speed of the die is 1000 mpm. Did not occur and the result was extremely satisfactory.

The wire No. manufactured by the diamond die of the present invention was used. 1 to No. As a result of welding using No. 8, the wire feedability, welding workability, and welding quality were all good.

In the comparative examples, No. In No. 9, since the reduction angle β was large, the P value exceeded 1.5 and the wire was disconnected.

No. In No. 10, the wire surface was scratched because the reduction angle β was small.

No. No. 11 has a large approach angle α. In No. 12, since the arc radius R at the entrance of the die was large, all of them were broken, and the wire surface was flawed.

No. In No. 13, since the arc radius R of the die entrance was small, the wire surface was scratched.

No. No. 14 is too long with respect to the bearing inner diameter d. 17 has a small relief angle θ,
In each case, the die was rough and the wire surface was scratched.

No. In No. 15, since the length with respect to the bearing inner diameter d was short, the outer diameter of the wire became unstable.

No. In No. 16, the die was damaged during wire drawing because the relief angle θ was large.

No. No. 18 has a low iron powder ratio. 19 had a low flux filling rate, and could be drawn without any disconnection or wire surface flaw, but the welding amount was small in a welding test performed separately.

In the above embodiment, an example of copper plating is shown. However, the present invention can be similarly applied to a non-plated wire on which copper plating is not applied. Also, the finished outer diameter of the primary wire drawing is 3.
Although it is set to 2 mm, the P value can be prevented from increasing by using an appropriate number of diamond dies according to the present invention even if the diameter is different due to the facilities and the like.

Further, the diamond die of the present invention can be applied to, for example, wire drawing of a flux-cored wire for stainless steel using stainless steel as the outer skin, regardless of the material of the outer skin.

[0044]

According to the present invention, 10 to 80% by weight
Flux containing iron powder of 12 to
When manufacturing a flux-cored wire in which 25% of the wire is filled and the wire is drawn to a small diameter, the wire can be drawn without lowering the drawing speed and without causing breakage at the time of drawing or scratching of the wire surface. Therefore, the productivity of the flux-cored wire can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing an L sectional view of a flux-cored wire.

FIG. 2 is a view showing a behavior of a flux in a cross section of a wire L when a flux density is lowered by wire drawing of a die.

FIG. 3 is a diagram showing a change in the thickness of the cross section of the wire L when the wire of FIG. 3 is further drawn and the flux density increases.

FIG. 4 is a sectional view showing a shape of a diamond die.

FIG. 5 is a sectional view showing the shape of another diamond die.

[Explanation of symbols]

 1 skin material 2 flux 3 air gap, A bell part B approach part C, G reduction part D, H bearing part E, I relief part F dice entrance part α bell angle β approach angle γ reduction angle θ relief angle R dice entrance part Arc radius a Maximum thickness b Minimum thickness

Claims (4)

[Claims] 1. A bearing inner diameter d of 0.78 to 5.0 m
m, a reduction angle γ of 4 to 10 °, a diamond die for flux-cored wire drawing. 2. An approach angle β 4 to 14 ° and a bearing length of 0.20 to 0.80 d with respect to a bearing inner diameter d.
2. The diamond die for flux-cored wire drawing according to claim 1, wherein the relief angle θ is 20 to 60 °. 3. The bearing inner diameter d is 0.78 to 5.0 m.
m, the bearing length is 0.2 with respect to the bearing inner diameter d.
0 to 0.80 dmm, reduction angle γ4 to 10 °,
A diamond die for flux-cored wire drawing, wherein the arc radius of the die entrance is R 0.8 to 2.0 mm and the relief angle θ is 20 to 60 °. 4. A flux containing 10 to 80% by weight of iron powder in a weight ratio of 12 to 25% by weight of the flux-cored wire.
4. The diamond die for drawing a flux-cored wire according to claim 1, which is used for drawing a filled flux-cored wire.