JPH04300095A - Manufacturing method of steel wire for gas shielded arc welding - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for manufacturing steel wire for CO2 gas shield automatic and semi-automatic arc welding, and is a method for manufacturing a welding wire that stabilizes welding workability and wire feedability and improves targetability. Regarding the method.

0002

[Prior Art] As shown in Figure 2, welding wire is generally produced by pickling and rough drawing a hot-rolled raw steel wire, and then going through the steps of annealing, plating, finishing wire drawing, and skin pass. has been done. In this manufacturing method, by leaving an appropriate amount of grain boundary oxidation layer on the surface layer of the wire, the action of oxygen in the grain boundary oxidation layer and the presence of oil at the grain boundary improve feedability during welding. Attempts are known in which the interface layer groove prevents slipping on the feed roller, and a stable wire feed speed is obtained, resulting in good welding workability. However, it is almost impossible to find manufacturing conditions under which a grain boundary oxidation layer can be uniformly formed on the steel substrate on the surface of the wire. The oxidation state of the steel base changes depending on the rolling conditions during raw wire rolling. Further, even if a grain boundary oxidation layer is formed, uniform grain boundary oxidation cannot be obtained. It is not possible to make the grain boundary oxidation layer uniform by drawing these raw wires with a die. Further, when the grain boundary oxidation layer is made deep, the plating becomes rough and peeling occurs, which significantly impairs productivity.

On the other hand, in order to form a uniform grain boundary oxidation layer and surface scale layer by intermediate annealing in the manufacturing process, the surface scale layer must be completely removed by the subsequent pickling process, and the optimum amount of grain boundary oxidation must be achieved. The layer must remain uniform. However, it is extremely difficult to leave a desired grain boundary oxidation layer uniformly. That is, the strength of the pickling conditions after intermediate annealing varies significantly. If it is weak, surface scale will remain and the adhesion of the plating will be poor. In this case, plating powder peeled off during welding accumulates in the conduit tube, torch, and tip, resulting in poor feeding and welding defects. On the other hand, if the pickling conditions are too strong, the grain boundary oxidation layer will partially dissolve, making it impossible to obtain a uniform grain boundary oxidation layer. As a result, uniform grooves cannot be formed on the wire surface, causing slippage on the feed roller during welding, resulting in poor welding.

[0004] Recently, there has been a demand for a welding wire that emphasizes targetability as an alternative welding wire with excellent straightness. The characteristics of this wire are to have appropriate tensile strength and to prevent plastic deformation of the wire. The manufacturing method for this wire differs from the process described above, in that in order to obtain high tensile strength, the wire diameter is made thicker in the intermediate annealing process than in the past, increasing the area reduction rate after annealing, and taking work hardening into consideration. It started to be taken. This manufacturing method involves annealing the wire to a diameter of 5.5 mm to 4.0 mm, performing electrolytic degreasing and electrolytic pickling as pre-plating treatment, plating, and drawing the wire to the product diameter in the final wire drawing process. . Since the welding wire obtained in this way does not have an annealing process before the plating process,
The lubricant is not completely eluted by electrolytic degreasing.

Dry lubricants (sodium stearate, calcium stearate, barium stearate, or inorganic hydroxide or calcium) used during rough wire drawing remain attached to the wire surface, deteriorating welding workability. In other words, if Ca, Na, and Ba remain attached, spatter will occur frequently during welding, the arc will become unstable, and Ca, N
It has been found that arc breakage occurs when the amount of a and Ba deposited is large.

[0006]

[Problems to be Solved by the Invention] The conventional steel wire for gas-shielded arc welding described above has dry lubricant remaining on its surface, impairing welding workability, and a solution to this problem requires an annealing process. Therefore, the production process was complicated. The present invention is a method for manufacturing a welding wire having high tensile strength by removing lubricant remaining on the surface of a welding steel wire that is bad for welding workability, and the weldability of the wire manufactured by this method is reduced by spatter. To provide an excellent method for manufacturing a welding wire that prevents frequent occurrence of , stabilizes the arc, and improves feedability.

[0007]

[Means for Solving the Problems] The gist of the present invention is to maintain the quality of steel wire for gas-shielded arc welding by reducing the amounts of Ca, Na, and Ba in the surface steel base to a predetermined amount or less, and This method provides a wire manufacturing method in which pear-shaped depressions are created on the wire surface and a predetermined amount of lubricating oil is adhered to the wire surface, especially sodium stearate, calcium stearate, which remains crimped when passing through a die during wire drawing. This relates to a manufacturing method in which dry lubricants such as barium stearate are removed without going through an annealing and pickling process. Specifically, in the raw wire drawing process, calcium stearate and stearic acid, which are sources of Ca, Na, and Ba, are removed. Steel wire for gas shielded arc welding is drawn using a lubricant containing one or more of barium or sodium stearate, cleaned using an abrasive and an alkaline surfactant, and then coated with lubricating oil. It's in the manufacturing method.

[0008]

[Operation] Next, the method of manufacturing the steel wire for gas shielded arc welding of the present invention will be explained in detail. The wire of the present invention is manufactured through the steps shown in FIG. Diameter 6.0-4.5mm
To prevent rapid cooling during annealing or rolling, the hot-rolled raw wire rod is adjusted in tensile strength in a heating and insulating furnace, and then descaled in a descaling machine, pickled, neutralized, dried, and then drawn. I do. In this case, put dry lubricant into each die box to reduce the area reduction rate between the dies in the range of 15 to 30%, prevent roughness of the dies during wire drawing, and obtain high productivity. There is.

As the lubricant used in the present invention, one or two types of industrial calcium stearate, barium stearate, sodium stearate, and inorganic calcium hydroxide are used, and the wire is drawn to a product size. In this case, the dry lubricant is brought into the die at the same time as the wire passes through the die, improving wire drawability, and the lubricant is pressed into the recesses on the wire surface and remains, and is not sufficiently removed by electrolytic degreasing or electrolytic pickling. . It also causes the degreasing solution to become extremely sludged.

Conventionally, since the lubricant on the wire surface was subjected to intermediate annealing, it was thermally decomposed to form carbides and inorganic substances (Ca, N).
a, Ba), so that almost satisfactory removal was achieved by electrolytic pickling after electrolytic degreasing. However, since the manufacturing method of the present invention omits the intermediate annealing process as shown in Figure 1, wire drawing is performed up to the product size in one step, and a predetermined abrasive and alkali are used to remove the lubricant from the wire surface. The product is manufactured using a cleaning solution containing a surfactant. We have put into practical use a cleaning device that easily removes dry lubricant in one step and provides a wire with a surface that is easy to coat with lubricant. By installing this cleaning equipment, the wire surface was found to have sufficient quality as a welding steel wire, as the electrolytic degreasing, electrolytic pickling, and plating steps that are normally required in the pre-plating process could be omitted.

[0011] The cleaning device used in the present invention performs both elution by chemical action for dry lubricant removal and polishing by physical action. FIG. 3 is a schematic diagram showing the cleaning device, and FIG. 4 is a sectional view of the lubricant removing device. First, the steps of removing the lubricant and forming the pear-like depressions will be explained. An alkaline surfactant and an abrasive are placed in the lubricant removing liquid tank 4 and fed into the nozzle 1 at high pressure by the first pump 5, and when they collide with the wire surface, a jet flow is generated within the nozzle 1. At this time, the alkaline surfactant that contributed to the jet flow is discharged from the lower discharge port and returned to the lubricant removal liquid tank 4. To compensate for the drop in the liquid level in the lubricant removal liquid tank 4, replenishment liquid is supplied from the tank 8 by the replenishment pump 10. Also, if the polishing agent is insufficient, use the lubricant removal liquid tank 4.
Adjust by adding an appropriate amount.

Next, in the cleaning process, a cleaning liquid heated by a heater 9 is introduced into a tank 8 by a supply pump 11 into a cleaning agent tank 6, and a high-pressure cleaning liquid is sent into a second cleaning nozzle 2 by a second pump 7. When the wire impinges on the entire surface of the wire from the supply port 18, the jet stream activates the wire surface within the nozzle. The liquid that contributed to the activation is circulated to the cleaning agent tank 6, and cleaning liquid is replenished to compensate for the drop in the liquid level. The liquid draining nozzle 3 is installed in a direction opposite to the direction in which the wire passes, so that air hits the wire at high pressure, and compressed air is sent from a compressor 15 to completely remove the cleaning agent adhering to the wire surface. The lubricant floating in the tanks 4 and 6 is discharged from the upper part of the tank through pipes 12 and 13 and together with the liquid drained from the nozzle 3 by a discharge pump 14. The sludge accumulated at the bottom of the tanks 4 and 6 is appropriately discharged through a waste pipe 17. Therefore, contamination of the liquid inside both tanks is extremely low.

The cleaning liquid in the first cleaning nozzle 1 contains an alkaline degreaser and fine particles of zircon sand, rutile, carborundum, etc. with a particle size of 0.074 to 0.5 mm (32 to 200 mm).
A suitable mixture of hard abrasives (mesh) is added and blown in from the first cleaning liquid pump 5 at high pressure. This first cleaning nozzle 1
The number of installations varies depending on the amount of lubricant applied. The cleaning solution is a solution and abrasive agent applied to the wire surface under high pressure (approximately 5 to 20 kg/cm).
In step 2), the lubricant collides with the wire and is removed by polishing, and is further eluted by chemical action. The polishing liquid is heated to 25 to 70° C. by a heater 9 provided in a tank 8, and is sent from pumps 10 and 11 to maintain a predetermined temperature. In other words, there is a collision mark of size 5 on the wire surface that the abrasive collided with.
A pear-shaped depression of ~20 μm is formed, and the alkaline degreasing liquid is passed from the cleaning liquid pump 7 through the cleaning nozzle 2 and hits the entire wire to clean the surface. The water adhering to the cleaned wire is
The drying nozzle 3 sprays compressed air to drain and remove the liquid, thereby drying the wire. In this way, by providing the above-mentioned cleaning device after the wire drawing step and further incorporating an oil applicator, a method for producing a non-plated wire was obtained with an extremely simplified process.

[0014]

[Example] A hot-rolled raw wire with a diameter of 5.5 mm was heat-treated to make the strength of the raw wire uniform, and the rust was removed using a rust removal machine, and the scale remaining in the pickling (HCl) process was removed. rust). The wire is washed with water, soaked in lime, neutralized and dried. The dried raw wire is then drawn to a diameter of 1.2 mm using a 13 die process. At this time, in order to reduce the friction between the wire and the die, we also used a dry lubricant (calcium stearate) in the die box to extend the life of the die. At this time, dry lubricant was pressed onto the surface of the wire as it passed through the die, but this pressed lubricant could be removed quickly and instantaneously by the cleaning device shown in FIG. 3.

The operation of the cleaning device involves applying a cleaning agent (
The alkaline surfactant has a particle size of 0.5 to 0.074 mm (3
Zircon sand is a natural stone with a size of 2 to 200 mesh.
A mixture of rutile, carborundum, etc., or a mixture of two or more of them at a ratio of 10 parts to 1 part of polishing agent is heated to a predetermined temperature, preferably 25 to 70°C.
heated and maintained at high pressure, preferably 5 to 20 kg/
When the lubricant is sprayed at a velocity of cm2, a high-speed jet is generated in the first nozzle 1, and the natural stone collides with the wire surface, polishing off the lubricant adhering to the wire and chemically eluting it with the cleaning liquid. The remaining amount of Ca, Ba, and Na is desirably 5 mg/100 g wire or less.

On the other hand, when the abrasive hits the wire surface under high pressure, impact marks are left. This trace is called a pear-shaped depression, and its diameter is preferably 5 to 20 μm; if it exceeds 20 μm, the wire skin becomes rough and the load on the feed motor during welding increases. Also,
If it is less than 5 μm, the wire skin is too flat and the amount of lubricant oil attached is small, which causes poor feeding performance.

FIG. 5 is a diagram showing the relationship between the type of liquid and the amount of lubricant removed in the manufacturing method of the present invention. It can be seen that what was there was reduced by approximately 50% by physical action, and further removed to less than 5 mg/100g by chemical action.

FIG. 6 shows a polishing liquid prepared at a ratio of 1 part abrasive to 10 parts alkaline surfactant, put into the lubricant removing device shown in FIG. The diameter of the pear-shaped depression was measured. As a result, at 5Kg/cm2, a slight pear-shaped dent occurs, measuring 2.4 to 9.8 μm, but as the hydraulic pressure increases, the pear-shaped dent becomes larger, and at 15 Kg/cm2, it becomes 5.1 to 20 μm.
μm, further increase the liquid pressure to 20Kg/cm2, 7
The diameter of the pear-shaped recess increases to 26 μm or more, reaching 20 μm or more. It was found that the surface of the wire in this state became rough.

On the other hand, when the relationship between the diameter of the formed pear-shaped depression and the amount of oil applied was investigated, it was found that the amount of oil applied increased in proportion to the size of the pear-shaped depression. This proves that oil has adhered to the pear-shaped depressions. Therefore,
The amount of oil applied that can contribute to feeding performance is 0.3 to 1.0 g/
In order to secure a 10 kg wire, the diameter of the pear-shaped recess is limited to 5 to 20 μm. Furthermore, if the diameter of the pear-shaped recess exceeds 20 μm, the amount of oil attached increases, but the wire surface becomes too rough and good feeding performance cannot be obtained.

[0020] After removing the lubricant, high-pressure cleaning is performed, and the water adhering to the wire surface is removed using a high-pressure nozzle. After that, the wire surface is coated with 10 kg of lubricating oil using an automatic oil applicator. By depositing 0.3 to 1.0 g per portion, there is a remarkable effect on improving feedability and preventing rust. If the amount of lubricating oil is less than 0.3g/10Kg, it will cause poor feeding, and if it exceeds 1.0g/10Kg, the feedability will improve, but the oil will decompose in the weld metal and hydrogen will remain. Defects occur. The amount of oil is controlled by the size of the pear-shaped depressions, and the particle size is 20 μm.
It has been found that when the surface of the wire becomes rough, the load on the wire feeding motor increases, resulting in poor feeding.

[0021] Steel manufactured by the manufacturing method of the present invention (JIS
The welding performance of Z3122 YCW11) wire was investigated and evaluated from two points: arc stability and feedability. The results are shown in Table 1. As can be seen from Table 1, the conventional three steps of intermediate annealing, plating, and final wire drawing could be manufactured in one step, and an excellent product with good performance could be obtained.

[0022]

[Table 1]

[0023]

[Effects of the Invention] According to the manufacturing method of the present invention, the process from the raw wire to the product can be simplified, and the dry lubricant that causes arc breakage during welding can be easily removed. This enabled consistent and effective manufacturing.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the manufacturing process of the present invention.

FIG. 2 is a block diagram of a conventional manufacturing process.

FIG. 3 is a schematic diagram of a cleaning device used in the present invention.

FIG. 4 is a cross-sectional view of the lubricant removal and cleaning nozzle shown in FIG. 3;

FIG. 5 is a graph showing the relationship between the remaining amount of cleaning liquid and dry lubricant.

FIG. 6 is a graph showing the relationship between the ejection pressure of a lubricant remover, the size of a pear-like depression, and the amount of oil adhesion.

[Explanation of symbols]

1 First cleaning nozzle 2 First cleaning nozzle 3 Nozzle 4 First cleaning liquid tank 5 Pump 6 Second cleaning liquid tank 8 Hot water tank 9 Heater 10 Hot water pump 14 Discharge device 15 Compressor 16 Wire

Claims (1)

[Claims] Claim 1: In a method for producing steel wire for gas-shielded arc welding, a wire raw wire is subjected to a wire drawing process in which Ca and Na are added to the wire.
The wire is drawn using a lubricant containing one or more of the Ba sources calcium stearate, barium stearate, or sodium stearate, and the wire surface is high-pressure washed using an abrasive and an alkaline surfactant. A method for manufacturing a steel wire for gas-shielded arc welding, characterized in that a lubricating oil is then applied.