JPH11285892A - Manufacturing method of small diameter flux cored wire for stainless steel welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of times of annealing for continuous drawing at a high speed in drawing a small-diameter flux-cored wire for welding stainless steel having a high flux filling rate and a large amount of alloy in the filling flux. Provided is a method for producing a small-diameter flux-cored wire for welding stainless steel, which does not cause disconnection, has good productivity, and is low in production cost. SOLUTION: In a method of manufacturing a small-diameter flux-cored wire for welding stainless steel, a wire strand having a stainless steel outer shell filled with flux is continuously drawn by a plurality of cassette type roller die unit groups, and the cassette is drawn. The total area reduction rate of the mold-type roller dice unit group is set to 92% or less, and the area reduction rate of each cassette-type roller dice unit is 30% or less until the cumulative area reduction rate of the cassette-type roller dice unit group is less than 85%. Area reduction rate of 85 to 92
% Is set to 20% or less, and further, the difference in the area reduction ratio between each cassette type roller die unit is gradually reduced by 0.7% or more, and the wire is drawn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a wire having a wire diameter of 0.8 to 0.8 mm.
The present invention relates to a method for manufacturing a small-diameter flux-cored wire for stainless steel welding of 1.6 mm, and more particularly to a method for manufacturing a small-diameter flux-cored wire for stainless steel having a high flux filling ratio (weight ratio of flux to the total weight of the flux-cored wire).

[0002]

2. Description of the Related Art Welding of stainless steel involves automation of welding,
Labor saving has been promoted, and as the welding wire used for these weldings, a small-diameter flux-cored wire, which has features such as high-efficiency welding, little spatter, and a beautiful bead shape, is remarkably excellent. The demand for semi-automatic and fully automatic welding is increasing.

[0003] In particular, in recent years, demand for a small diameter flux-cored wire having a diameter of 1.0 mm or less has been rapidly increasing due to all-position welding and improvement in performance of application to thin steel plates.

[0004] However, the small-diameter flux-cored wire for welding stainless steel has a large work hardenability of the stainless steel itself used as the outer skin as compared with the small-diameter flux-cored wire for mild steel welding, and furthermore, the composition and purpose of the stainless steel in the outer skin. In order to adjust the difference with the weld metal component to be welded or to improve the welding efficiency, the filling rate of the flux containing the alloy component became inevitably high, the outer skin thickness was thinned at the time of drawing, and the wire often broke. . For this reason, the productivity of the small-diameter flux cored wire for welding stainless steel has been extremely low.

[0005] As a method for improving such a problem in the wire drawing process of a small diameter flux cored wire for stainless steel welding, annealing is performed during the wire drawing process to maintain the Vickers hardness of the outer skin at 300 or less. A technique for performing wire drawing is disclosed in Japanese Patent Application Laid-Open No. Sho 59-130698. Further, Japanese Patent Application Laid-Open No. 61-212500 discloses a technique of drawing and filling a flux obtained by granulating a fine powder flux material and drawing the wire. However, in these methods, since the diameter is reduced by the wire-shaped die drawing, all of the processing force of the filling flux and the frictional force with the hole-shaped die act as a pulling force to the outer skin, and further, since the alloy component is high, the hole diameter is reduced. The flux fluidity at the time of drawing the mold die is deteriorated, and the alloy components are clumped into the outer skin, so that the outer skin is greatly reduced in ductility, and the wire is easily broken.

[0006] When the wire is broken, the larger the drawing speed, the larger the number of hole-shaped dies that have been broken, and the number of times that the wire needs to be passed through the hole-shaped die again increases. In order to pass through the die, it is necessary to make the wire tip thinner for each die.
Decrease productivity.

On the other hand, Japanese Patent Publication No. 2-29638 discloses a wire drawing method using a cassette type roller die as a wire drawing method for preventing disconnection during wire drawing. When a roller die is used, rolling friction occurs to reduce external friction, and no excessive force acts on the wire strand. Further, since the processing is performed while changing the wire cross-sectional shape by the elliptical roller groove, it is considered that there is an effect of crushing the filling flux and an effect of preventing the alloy component from being formed into a block. With the above effects, disconnection is prevented.

[0008] However, even if the wire is drawn using the cassette type roller die described in Japanese Patent Publication No. 2-29638, the wire is still broken when drawn at a high speed, and further improvement in productivity has been desired.

[0009]

SUMMARY OF THE INVENTION The present invention relates to a high-speed flux-drawing wire for a stainless steel welding small-diameter flux-cored wire having a high flux filling rate and a large amount of alloy in the filled flux. An object of the present invention is to provide a method for producing a small-diameter flux-cored wire for stainless steel welding, which does not break even when continuously drawn, has good productivity, and is low in production cost.

[0010]

SUMMARY OF THE INVENTION The present inventor has succeeded in continuously drawing a wire strand having a stainless steel sheath filled with a flux with a plurality of cassette type roller dice unit groups to reduce the number of cassette type roller dice units. The authors found that by gradually reducing the surface area in accordance with the increase in the skin hardness and continuously drawing a small-diameter flux-cored wire for stainless steel welding, disconnection can be prevented even if the number of times of annealing is reduced. Completed the invention.

[0011] The gist of the present invention is as follows: (1) In a method of manufacturing a small-diameter flux-cored wire for stainless steel welding, a plurality of cassette-type roller die unit groups are used to continuously form a wire with a stainless steel sheath filled with flux. And the total area reduction rate of the cassette-type roller dice unit group is set to 92% or less, and the cumulative area reduction rate of each cassette-type roller dice unit group is 85%.
30% or less up to less than 20%, and 20% or less when the cumulative area reduction rate is 85 to 92%. Further, the difference in the area reduction rate between each cassette type roller die unit should be gradually reduced by 0.7% or more. Features.

(2) The method for producing a small-diameter flux-cored wire for welding stainless steel according to (1), wherein the wire is drawn by a plurality of continuous cassette-type roller die units and then finished by a hole die. Method.

(3) The wire strand diameter before drawing is 2.5 to
The method for producing a small-diameter flux-cored wire for welding stainless steel according to (1) or (2), wherein the flux filling rate is 5 mm and the flux filling rate is 16 to 36%.

Incidentally, the area reduction ratio in the present invention is represented by the following equation.

Reduction area = ｛1− (wire cross-sectional area after processing /
Wire cross-sectional area before processing) x 100

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a schematic view showing the steps of a method for manufacturing a small-diameter flux-cored wire for welding stainless steel according to the present invention. The wire 2 unwound from the wire supply table 1 is wound around the take-up capstans 5-1 to 5-N and drawn by the cassette type roller die units 3-1 to 3-N. Cassette type roller die unit 3-1 to 3-N
As shown in FIG. 2, a plurality of small-diameter roller pairs 4-1 and 4-2 (one pair per roller, three to five in the figure) are rotated by 90 degrees.
It is assembled by changing the angle every ° and approaching. Next to the cassette type roller die units 3-1 to 3-N, a plurality of units (seven units in FIG. 1) are used to reduce the diameter of the wire to a predetermined size using the take-off capstans 5-1 to 5-N. . Next, when the hardness of the wire sheath is high, the wire sheath is softened by annealing in a heat treatment furnace 6 as necessary, and then finished and drawn to a product diameter wire 8 using a hole die 7 and wound up by a winding machine 9. And wound product wire.

FIG. 3 shows the cumulative area reduction rate and the wire sheath when a wire filling wire having a flux filling rate of 23% corresponding to JIS Z3323 YF309L and an outer diameter of 4.5 mm is drawn using a hole type die and a cassette type roller die. The hardness relationship is shown. In the case of the hole-type die drawing, when the cumulative area reduction rate exceeds 50%, the wire skin hardness Hv becomes 350 or more, and when it exceeds 70%, the wire skin hardness Hv exceeds 380. on the other hand,
When the cassette type roller die is used, the wire skin hardness Hv is 350 even when the cumulative area reduction rate is about 90%, and the wire skin hardness is compared even when the cumulative area reduction rate is higher than that of the hole type die drawing. You can see that it is very low.

Therefore, a plurality of cassette-type roller dice units are used to continuously draw a wire strand in which a flux is filled in a stainless steel shell, and the surface reduction rate of each cassette-type roller dice unit is increased to increase the skin hardness. By successively drawing the small-diameter flux-cored wire for stainless steel welding with a gradual decrease in accordance with it, disconnection can be prevented even if the number of times of annealing is reduced.

The total area reduction rate of wire drawing from the wire strands by the cassette type roller dice unit group is 92% or less. If this total area reduction ratio exceeds 92%, the wire sheath hardness becomes high, and even if the wire is drawn with a cassette type roller die, the wire breaks.

The area reduction rate of each cassette type roller dice unit in the wire drawing step is 30% or less when the cumulative area reduction rate from the wire strand diameter is less than 85%, and the cumulative area reduction rate is 85 to 92.
% Should be 20% or less, and the difference in the area reduction ratio between each cassette type roller die unit must be gradually reduced by 0.7% or more for drawing. If the area reduction rate of each cassette type roller dice unit exceeds 30% until the cumulative area reduction rate is less than 85%, the cumulative area reduction rate is 85 to 92% and the area reduction rate of each cassette type roller dice unit is 20%. When the value exceeds, the surface reduction rate of the cassette type roller die unit with respect to the hardness of the wire sheath is too large, and disconnection frequently occurs. Further, if the difference in reduction in area between the cassette-type roller dice units is gradually reduced to less than 0.7%, the amount of reduction in area in one set of cassette-type roller dice units is particularly large when wire drawing is performed at a high speed. As a result, a large tensile force acts between the take-up capstan and the take-off capstan to cause disconnection.

The reduction rate of each cassette type roller dice unit until the cumulative reduction rate is less than 85% is 15% or more in consideration of productivity and the reduction rate of each subsequent cassette type roller dice unit. Preferably, there is.

The above-mentioned cassette type roller dice unit draws wire while changing its cross-sectional shape with an elliptical roller groove, and the final roller die on the outlet side of the cassette type roller dice unit uses a circular roller groove. However, it is difficult to obtain a perfect circle with a small product diameter. Therefore, finish wire drawing is performed with 1 to 4 hole-shaped dies. When the wire sheath is hard, annealing is performed to soften the wire sheath and finish wire drawing is performed. Hole type die drawing in the finish wire drawing step can be performed by either dry wire drawing or wet wire drawing.

In the present invention, the wire strand diameter before drawing is 2.
5-5 mm is suitable. That is, the wire strand diameter is 2.5 mm
If it is less than 1, primary wire is frequently broken and the number of times of annealing increases. On the other hand, when the wire strand diameter exceeds 5 mm, the total area reduction rate until the wire is drawn to a desired thin product diameter is high (92%).
Even if it is a cassette type roller die drawing, the wire wire diameter is preferably 2.5 to 5 mm, because the wire sheath becomes hard and the wire is easily broken or the number of annealing increases.

The flux filling rate is required to be 16% or more in order to adjust the difference between the stainless steel shell component and the target weld metal component, increase the amount of the weld metal, and improve the welding workability. If the rate exceeds 36%,
The outer skin becomes too thin, and even if it is drawn under the above-mentioned conditions, disconnection is likely to occur.

[0025]

The present invention will be described in more detail with reference to the following examples.

First, a stainless steel pipe (outer diameter 20 mm, wall thickness 1.8 mm) having the components shown in Table 1 was reduced in diameter to a target flux filling rate, and then placed on a vibrating table as a coil winding. The flux of the components shown in Table 2 was 30
It was granulated to 0 μm or less, dried and filled with vibration.

[0027]

[Table 1]

[0028]

[Table 2] The stainless steel pipe filled with the flux was drawn to a wire diameter shown in Tables 3 and 4 with a hole die, and was subjected to a heat treatment at 1050 ° C. × 5 minutes in a hydrogen gas atmosphere to be subjected to each test.

Next, using the wire manufacturing apparatus shown in FIG. 1, 2,000 kg of the wire strands were each changed to a diameter of about 1.4 mm with a cassette type roller die, and the area reduction rate of each cassette type roller die unit was variously changed. Wire speed at exit of die roller die unit is 300m / min
, And the presence or absence of disconnection was investigated. After annealing at 1050 ° C. for 3 minutes in a hydrogen gas atmosphere, the wire was drawn to a product diameter of 0.8 to 1.2 mm with 3 to 4 hole-shaped dies. The results are shown in Tables 3 and 4.

Each cassette-type roller dice unit used was a combination of five cassette-type roller dies.

[0031]

[Table 3]

[0032]

[Table 4] In Tables 3 and 4, Test No. 1 to 3 are examples of the present invention, and test Nos. 4 to 8 are comparative examples.

In Test No. of the present invention, 1 to 3 indicate that the total area reduction rate from the wire strand of the cassette type roller die group is 9
3% or less, and the area reduction rate of each cassette type roller dice unit group is 3% until the cumulative area reduction rate from the wire strand is less than 85%.
0% or less, the cumulative area reduction rate of 85 to 92% is 20% or less,
In addition, since the difference in the area reduction ratio between each cassette-type roller die unit is gradually reduced by 0.7% or more, the wire can be drawn without breaking during the drawing of the cassette-type roller die without annealing. Was good and a very satisfactory result.

After drawing with a cassette type roller die,
Even after annealing and finish drawing to the product diameter with a hole die, there was no disconnection, and good welding workability was obtained in a welding test separately performed.

Test No. in the comparative examples. Test No. 4 shows that the reduction in area of each cassette type roller dice unit exceeded 30% until the cumulative reduction in area from the wire strand was less than 85%. Reference numeral 5 denotes a reduction in the surface area of the cassette-type roller die unit with respect to the hardness of the wire sheath because the cumulative area reduction rate of each of the cassette-type roller dice units was 85 to 92% and the reduction area of the cassette-type roller dice unit exceeded 20%. The rate was too high, causing disconnection.

Test No. In No. 6, since the surface reduction ratio difference between each cassette-type roller dice unit was gradually reduced to less than 0.7%, a large tensile force acted between the cassette-type roller dice unit and the take-off capstan, thereby breaking the wire.

Test No. In No. 7, since the diameter of the wire was large, the total area reduction rate from the wire in the cassette roller die drawing was high, and the outer skin was hardened and the wire was broken.

Test No. In No. 8, since the flux filling rate was high, the outer skin was too thin and the wire was broken.

[0039]

According to the present invention, in the production of a small-diameter flux-cored wire for welding stainless steel having a high flux filling rate and a large amount of alloy in the filling flux, the number of times of annealing is reduced and the continuous elongation is performed at a high speed. Wire can be drawn without breaking even if it is drawn. As a result, the productivity of a small-diameter flux cored wire for welding stainless steel is improved, and the manufacturing cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic view showing an example of steps of a method for producing a small-diameter flux-cored wire for welding stainless steel according to the present invention.

FIG. 2 is a configuration diagram of a cassette type roller die.

FIG. 3 is a diagram showing a relationship between a cumulative wire-reduction ratio of wire drawing by a hole-type die and a cassette-type roller die and a wire skin hardness.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 wire supply stand 2 wire strand 3, 3-1 to 3 -N cassette type roller dice unit 4-1, 2 small roller pair 5, 5-1 to 5 -N take-up capstan 6 heat treatment furnace 7 hole die 8 Product diameter wire 9 winder

Claims (3)

[Claims] 1. A method for manufacturing a small-diameter flux-cored wire for welding stainless steel, comprising: a step of continuously drawing a wire strand having a stainless steel sheath filled with flux by a plurality of cassette type roller die units; The total area reduction rate of the cassette type roller dice unit group is 92% or less, and the area reduction rate of each cassette type roller dice unit is 30% or less until the cumulative area reduction rate of the cassette type roller dice unit group is less than 85%. Cumulative area reduction rate of 85 to 92
% Is set to 20% or less, and further, the difference in area reduction between each cassette type roller die unit is gradually reduced by 0.7% or more, and the wire is drawn. 2. The method for producing a small-diameter flux-cored wire for welding stainless steel according to claim 1, wherein the wire is drawn by a plurality of continuous cassette-type roller die units and then finished by a hole die. . 3. The wire strand diameter before drawing is 2.5 to 5 m.
The method for producing a small-diameter flux-cored wire for welding stainless steel according to claim 1 or 2, wherein the flux filling rate is 16 to 36%.