JP2898430B2 - Steel wire for gas shielded arc welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention CO ₂ gas shielded automatic BACKGROUND OF relates semiautomatic arc welding wire, the welding workability, wire feed to stabilize the sheet resistance, about and welding wire with improved target resistance.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 2, a steel wire for welding is manufactured by pickling a hot-rolled steel wire, performing rough drawing, annealing, plating, finish drawing, and skin pass. I have. In this manufacturing method, by leaving an appropriate amount of the grain boundary oxide layer in the surface layer of the wire, the function of oxygen in the grain boundary oxide layer and the presence of oil in the grain boundary part improve the feedability at the time of welding. It is known that the field oxide layer groove prevents slipping at the feeding roller, obtains a stable wire feeding speed, and obtains good welding workability. However, the production conditions under which the grain boundary oxide layer can be uniformly obtained on the steel substrate on the surface of the wire cannot be said to exist at all. That is, the oxidation state of the steel base material changes depending on the rolling conditions at the time of raw rolling. Even when a grain boundary oxide layer is formed, uniform grain boundary oxidation cannot be obtained. These original wires cannot be drawn by a die to make the grain boundary oxide layer uniform. Further, when the grain boundary oxide layer is made deep, the plating ground becomes rough, and the plating is peeled off, and the productivity is remarkably deteriorated.

On the other hand, in order to form a uniform grain boundary oxide layer and a surface scale layer by intermediate annealing in a manufacturing process, the surface scale layer is completely removed by a subsequent pickling step, and an optimum amount of the grain boundary oxide layer is formed. The layers must remain uniform. However, it is extremely difficult to leave a desired grain boundary oxide layer uniformly. That is, the strength of the pickling conditions after the intermediate annealing significantly fluctuates. If it is weak, the surface scale remains and the adhesion of the plating is poor. In this case, the plating powder peeled off during welding accumulates in the conduit tube, torch, and chip, resulting in poor feeding and welding defects. On the other hand, if the pickling conditions are too strong, the grain boundary oxide layer is partially dissolved and a uniform grain boundary oxide layer cannot be obtained. For this reason, a uniform groove cannot be obtained on the surface of the wire, causing slippage at the feed roller during welding, resulting in poor welding.

[0004] Recently, there has been a demand for a wire which emphasizes the target property as a welding wire having an excellent straightness in place of the above. The characteristics of the wire are such that the wire has an appropriate tensile strength to prevent plastic deformation of the wire. Unlike the above-mentioned process, this wire manufacturing method uses a method that takes into account work hardening by increasing the wire diameter in the intermediate annealing step, increasing the area reduction after annealing, and considering work hardening in order to obtain high tensile strength. Began to be taken. In this manufacturing method, the wire diameter at the time of annealing is 5.5 mm to 4.0 mm, and after electrolytic degreasing and electrolytic pickling as plating pretreatment, plating is performed, and the wire is drawn to a product diameter in a finishing wire drawing process. . Since the welding wire thus obtained has no annealing step before the plating step, the lubricant is not completely eluted by electrolytic degreasing.

[0005] The dry lubricant (sodium stearate, calcium stearate, barium stearate, or inorganic calcium hydroxide) used at the time of rough drawing of the welding wire adheres to the wire surface and deteriorates welding workability. That is, it has been found that when Ca, Na, and Ba adhere to the wire, spatter frequently occurs during welding and arc becomes unstable, and when a large amount of Ca, Na, and Ba adhere, the arc breaks.

[0006]

As described above, in the conventional steel wire for gas shielded arc welding, a dry lubricant remains on the surface of the steel wire to deteriorate welding workability. Required, which complicated the production process. The present invention is a welding wire having a high tensile strength by removing a lubricant having poor welding workability remaining on the surface of a welding steel wire, and the welding property of the wire prevents occurrence of spatter, thereby preventing arcing. Provided is an excellent welding wire that is stabilized and has improved feedability.

[0007]

SUMMARY OF THE INVENTION The gist of the present invention is to maintain the quality of a steel wire for gas shielded arc welding by using a dry process such as sodium stearate, calcium stearate, barium stearate, etc. on a wire surface steel base. Provide a wire in which the amount of lubricant (Ca, Na, Ba) is not more than a predetermined amount and a pear-shaped recess is provided on the surface of the wire so that a predetermined amount of lubricating oil adheres and the tensile strength of the wire is further limited. For details, refer to Annealing
5-20 diameter on the surface of welding- free steel wire without plating
μm in the surface of the wire 10
5 mg or less per 0 g, and one or more of Na and Ba on the wire surface
It is characterized in that it is 5 mg or less per g, the amount of oil adhering on the wire surface is 0.3 to 1.0 g per 10 kg of wire, and the tensile strength is 90 to 140 kgf / mm ^2. It is a steel wire for gas shielded arc welding.

[0008]

Next, the steel wire for gas shielded arc welding of the present invention will be described in detail. The diameter of the pear-shaped recess on the wire surface is preferably 5 to 20 μm. If it exceeds 20 μm, the wire surface becomes rough and the load on the feed motor during welding increases. Further, in the case of a wire with plating, the plating adhesion is remarkably poor, and a plating peeling phenomenon occurs. On the other hand, if the thickness is 5 μm or less, the wire surface is too flat, and the amount of oil, which is a lubricant, is reduced, resulting in poor feedability.

If the amount of Ca, Na, or Ba adhered exceeds 5 mg, arc instability or arc breakage occurs and welding is interrupted. Therefore, it is desirable that the amount of the adhered Ca, Ba, and Na wires is 5 mg / 100 g or less. FIG.
In the manufacturing method of the present invention, a diagram showing the relationship between the type of liquid and the amount of lubricant removed, the average after rough drawing Ca, Ba,
The amount of Na adhered was 35 mg / 100 g, but was reduced by almost 50% due to physical action, and 5 mg / 100 g due to chemical action.
It turns out that it is removed to 100 g or less.

The amount of the lubricating oil deposited on the wire of the present invention must be 0.3 to 1.0 g per 10 kg of the wire in consideration of the feedability during welding and the adverse effect on the welded portion. That is,
If the amount of lubricating oil is less than 0.3 per 10 kg, the wire feedability is poor, the arc becomes unstable, various defects occur, and the rust prevention effect is small and the long-term storage property is poor. On the other hand, if the amount of the lubricating oil exceeds 1.0 g, fumes are frequently generated during welding and the conduit is dirty, so that the wire feedability is deteriorated.

Next, the tensile strength is desirably 90 to 140 kgf / mm ² . If it is less than 90 kgf / mm ² , it will bend during welding and plastic deformation will occur, and in extreme cases, the wire will buckle and welding will stop. On the other hand, the tensile strength is 140 kg
If f / mm ² is exceeded, it will not be possible to follow the bending of the conduit cable, and the feed resistance will increase, making welding impossible. The predetermined tensile strength of a product is experimentally determined based on the wire diameter of the original wire and the tensile strength and the processing rate up to the product.

One example of the method for manufacturing a wire according to the present invention is manufactured through the steps shown in FIG. In order to prevent rapid cooling during annealing or rolling of a hot-rolled raw material with a diameter of 6.0 to 4.5 mm, the tensile strength is adjusted with a heating and heating furnace, which is scaled down with a rust remover, pickled, medium After summing and drying, wire drawing is performed. In this case, a dry lubricant is put into each die box to reduce the area reduction rate between the dies in the range of 15 to 30%, to prevent the die from being roughened at the time of wire drawing, and to obtain high productivity. I have.

The lubricant used in the production of the wire of the present invention is generally a mixture of industrially used calcium stearate, barium stearate, sodium stearate and inorganic calcium hydroxide, and is drawn to the product size. In this case, the dry lubricant is brought into the die at the same time as the wire when passing through the die, improves the drawability, and the lubricant is pressed and held in the concave portion of the wire surface, and is not sufficiently removed by electrolytic degreasing and electrolytic pickling. . It also causes the degreasing solution to sludge significantly.

Conventionally, the lubricant on the wire surface has undergone thermal decomposition due to intermediate annealing after rough drawing and has been turned into carbides and inorganic substances (Ca, Na, Ba). Therefore, electrolytic pickling after electrolytic degreasing is performed. The removal was made to an almost satisfactory amount.

However, in the production example of the wire of the present invention, the intermediate annealing step is omitted as shown in FIG. 1, so that the wire is processed to a product size in one step by wire drawing to remove a lubricant on the wire surface. The product is produced using a cleaning liquid comprising an abrasive and an alkali surfactant. A cleaning device that removes dry lubricant easily in one step and obtains a wire having a surface on which lubricating oil is easily applied has been put to practical use. By using this cleaning device, it was found that the surface of the wire can be omitted from the electrolytic degreasing, electrolytic pickling, and plating steps in the usual plating pretreatment step, and that the wire has sufficient quality as a welding wire.

The cleaning apparatus used for manufacturing the wire according to the present invention comprises:
The elution by the chemical action by removing the dry lubricant and the polishing by the physical action are performed together. FIG. 3 is an overall schematic diagram showing the cleaning device, and FIG. 4 is a cross-sectional view of a lubricant removing and cleaning nozzle. First, the steps of removing the lubricant and forming the pear-shaped dent will be described. When an alkaline surfactant and an abrasive are put into the lubricant removing liquid tank 4 and fed into the nozzle 1 at a high pressure by the first pump 5 to collide with the wire surface, a jet flow is generated in the nozzle 1. At this time, the alkaline surfactant that has contributed to the jet flow is discharged from the lower outlet and returns to the lubricant removing liquid tank 4. Lubricant removal liquid tank 4
The replenishing liquid is supplied from the tank 8 by the replenishing pump 10 to the extent that the liquid level in the inside has dropped. When the amount of the polishing agent is insufficient, an appropriate amount is supplied into the lubricant removing liquid tank 4 for adjustment.

Next, in the cleaning step, the cleaning liquid heated by the heater 9 in the tank 8 by the supply pump 11 is supplied into the cleaning agent tank 6, and the high-pressure cleaning liquid is sent into the second cleaning nozzle 2 by the second pump 7. When the supply port 18 collides with the wire surface, the jet flow activates the wire surface in the nozzle. The liquid that has contributed to the activation is circulated to the cleaning agent tank 6 and the cleaning liquid is replenished to the extent that the liquid level has dropped. The liquid draining nozzle 3 is oriented in the direction opposite to the direction in which the wire passes, and is installed so that air impinges on the wire at a high pressure. Compressed air is sent from the compressor 15 to completely remove the cleaning liquid attached to the wire surface. The lubricant floating in the tanks 4 and 6 is discharged from the tank through pipes 12 and 13 and discharged from the nozzle 3 by the discharge device 14 together with the liquid drained. The sludge accumulated at the bottom of the tanks 4 and 6 is discharged to the waste pipe 1
7 to discharge as appropriate. Therefore, the contamination of the liquid inside both tanks is extremely small.

The cleaning liquid of the first cleaning nozzle 1 is composed of an alkali degreaser and a hard particle size of 0.5 mm to 0.074 mm (32 to 20 mm) such as fine-grained zircon sand, rutile, and carborundum.
(0 mesh) abrasive is appropriately mixed in, and is blown in at a high pressure from the first cleaning liquid pump 5. The number of the first cleaning nozzles 1 varies depending on the amount of the lubricant attached. In the cleaning liquid, the solution and the abrasive are applied to the wire at a high pressure (about 5 to 20 kg / cm ² ) on the wire surface, the lubricant is polished off, and further eluted by a chemical action. The polishing liquid is supplied to a heater 9 provided in a tank 8.
Hot water heated to 25 to 70 ° C. by the pump 10,
A predetermined temperature is maintained by being sent from 11. That is, a pear-shaped dent having a size of 5 to 20 μm is formed on the surface of the wire hit by the abrasive, and the alkaline degreasing solution passes through the cleaning nozzle 2 from the cleaning solution pump 7 and hits the entire wire to clean the surface.
The attached water of the washed wire is removed by spraying compressed air by the drying nozzle 3 to remove the liquid, and the wire is dried.
As described above, by providing the above-described cleaning device after the drawing process and further incorporating the oil applicator in the next process, it is possible to manufacture an unplated wire by a very simplified process.

[0019]

EXAMPLE A polishing liquid prepared at a ratio of an abrasive 1 to an alkaline surfactant 10 was put into the lubricant removing apparatus shown in FIG. 3, and was spouted at a pressure of 5 to 20 kg / cm ² to form on the wire surface. The diameter of the pear-shaped depression was measured. As a result, 5 kg / cm
^{In the case of 2} , the pear-shaped dent is slightly generated at 2.4 to 9.8 μm, but as the hydraulic pressure is increased, the pear-shaped dent becomes larger.
5.1-2.0 μm at Kg / cm ² , and further increase the liquid pressure to 20
When it was Kg / cm ² , the diameter of the pear-shaped dent was 7 to 26 μm, and when it was 20 μm or more, the surface of the wire surface was rough.

When the relationship between the diameter of the pear-shaped dent formed by the impact of the abrasive and the amount of oil applied was examined, the amount of oil applied increased in proportion to the size of the pear-shaped dent. This proves that oil adhered to the pear-shaped depression. Therefore, the oil adhesion amount that can contribute to the feeding property is 0.3 to 1.0 g / 10
To secure the Kg wire, the diameter of the pear-shaped recess should be 5 to 2
The size is limited to 0 μm. On the other hand, if the diameter of the pear-shaped dent exceeds 20 μm, the amount of adhering oil increases, but the wire surface is too rough to obtain good feedability.

After removing the lubricant, high-pressure washing is performed, and the water adhering to the wire surface is drained using a high-pressure nozzle, and then the lubricating oil is applied to the wire surface by an automatic coating machine on the wire surface per 10 kg of wire. By attaching 0.3 to 1.0 g, there is a remarkable effect on improving the feeding property and preventing the generation of rust. If the amount of lubricating oil is less than 0.3 g / 10 kg, poor feeding occurs, and if it exceeds 1.0 g / 10 kg, the oil proceeds in a good direction, but the oil decomposes in the deposited metal and hydrogen yields. Hydrogen deficiency occurs. It is the diameter of the pear-shaped dent that controls the amount of oil adhering. If the particle diameter exceeds 20 μm, the load on the wire feed motor increases with the wire surface roughened, resulting in poor feed. Was.

The wire of the present invention described above will be described in Table 1 together with a comparative example. The welding performance of the wire of the present invention was evaluated based on the wire feedability and the disturbance of the arc phenomenon together with the comparative example. In Table 1, No. 2 to 6 are inventive examples, and others are comparative examples. As a result, no. As shown in Fig. 4, the diameter of the pear-shaped depression is 5.4 µm, the amount of lubricant attached (Ca + Ba + Na) is 4.8 mg / 100 g, and the amount of oil attached is 0.38 g / 10 kg.
, The feeding property and the arc phenomenon were not disturbed and good evaluation was obtained. Further, when the diameter of the pear-shaped dent becomes smaller, the amount of lubricant attached increases, the amount of oil attached decreases remarkably, the feedability deteriorates and the turbulence of the arc phenomenon increases, and 7.8 mg / 100
In g, it was found that arc breakage and the like occurred. These phenomena are such that the electric conductivity during welding is disturbed due to an increase in the amount of lubricant adhering, and the arc is disturbed and the arc is broken in accordance with insufficient oil adhering amount. The adhesion oil used was prepared by mixing the vegetable oil 6 with the fatty acid ester 4 at a ratio.

If the diameter of the pear-shaped dent exceeds 20 μm, the skin on the surface of the wire is remarkably disturbed, the amount of lubricant attached is reduced and the amount of oil attached is increased, but the feed roller is roughened on the surface of the wire. It has been found that the feeding resistance in the conduit cable and the chip increases, causing a feeding failure and causing arc instability.

When the results shown in Table 1 were comprehensively evaluated as described in detail above, the amount of lubricant adhering to the wire surface was Ca
+ Na + Ba must be less than 5mg / 100g due to disturbance of electrical conductivity. If the amount of oil adhered is not more than 0.3g / 10kg, feed failure will occur. On the other hand, if it exceeds 1.0g / 10kg, hydrogen will be added to the weld metal. Due to the occurrence of defects caused by this, the content was set to 1.0 g / 10 kg or less. Furthermore, since the size and diameter of the pear-shaped dents are also caused by the amount of lubricant and oil adhering to the wire surface, the welding performance is sufficiently satisfactory by limiting the appropriate size of the pear-shaped dents to 5 to 20 μm. Was found to be able to be maintained.

[0025]

[Table 1]

The examples shown in Table 1 were produced by the following method. The hot-rolled 5.5 mm diameter wire is heat-treated to have a predetermined strength and uniformity of the wire. The rust is removed by a rust remover, and the scale (rust) remaining in the pickling (HCl) process is removed. Dissolve). This wire is washed with water, immersed in lime and neutralized and dried. The dried raw wire is drawn to a diameter of 1.2 mm using 13 dies. At this time, dry lubricant (one or more of calcium stearate, barium stearate or sodium stearate) is added to the die box to reduce the wear between the wire and the die.
Was used to extend the die life. At this time, a dry lubricant was pressure-bonded to the surface of the wire when passing through the die, and the pressure-bonded lubricant could be removed at high speed and instantaneously by the cleaning device. The linear speed in the washing process is 300m / m
conducted in. The tensile strength in each example was 1
The range was 10 to 126 kgf / mm ² .

The cleaning device is provided with a cleaning agent (alkaline surfactant having a particle size of 0.074-0.5 mm (200-3
A mixture of two or more of zircon sand, rutile, and carborundum as abrasives of 2 mesh) in a ratio of 10: abrasive 1 at a predetermined temperature, preferably 55 ° C. 15kg / cm
^A jet was sprayed at a high pressure of ^{2, and} a high-speed jet was generated in the nozzle to impinge the abrasive on the wire surface. Therefore, the lubricant adhering to the wire is removed by polishing, and a collision mark is left by the collision. Further, the lubricant is chemically eluted with the cleaning liquid. The remaining amount of the lubricant is 0.41 to 0.41 in total of Ca, Ba and Na.
7.85 mg / 100 g wire.

FIG. 5 shows an example of manufacturing a wire according to the present invention.
FIG. 5 is a graph showing the relationship between the type of liquid and the amount of lubricant removed, where the average amount of Ca, Ba, and Na adhered after rough drawing was 35 mg / 1;
It can be seen that the substance which was 00 g was reduced by almost 50% by the physical action, and was further reduced to 5 mg / 100 g or less by the chemical action.

FIG. 6 shows a polishing liquid prepared by mixing a polishing agent 1 in a ratio of alkaline surfactant 10 with an abrasive 1 into the lubricant removing apparatus shown in FIG. 3, and squirting under a pressure range of 5 to ²⁰ kg / cm ² to form on the wire surface. The diameter of the pear-shaped depression was measured. As a result, when the ejection pressure is 5 kg / cm ² , a pear-like dent is slightly generated at 2.4 to 9.8 μm, but the pear-like shape is enlarged as the pressure of the lubricant removing liquid is increased to 5.1 at 15 kg / cm ² . ~ 2
0 μm, further increase the pressure, 7 ~ ² at 20 kg / cm ²
At 6 μm, the diameter of the pear-shaped depression becomes large and becomes 20 μm or more. It was found that the wire surface skin in this state became slightly rough. Also, as the size of the pear-shaped dent increased, the amount of oil adhesion increased.

[0030]

According to the wire of the present invention, a very stable welding state can be obtained without breaking the arc at the time of welding and having good wire feedability. Also, the production process could be omitted in the production.

[Brief description of the drawings]

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

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

FIG. 3 is a schematic view of a cleaning device used for manufacturing the wire of the present invention.

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

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

FIG. 6 is a graph showing the relationship between the ejection pressure of a lubricant removing agent, the size of a pear-shaped dent, and the amount of oil adhesion.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st washing nozzle 2 1st washing nozzle 3 nozzle 4 1st washing liquid tank 5 pump 6 2nd washing liquid tank 8 Hot water tank 9 Heater 10 Hot water pump 14 Discharge device 15 Compressor 16 Wire

Continuation of the front page (56) References JP-A-54-131542 (JP, A) JP-A-61-27198 (JP, A) JP-A-60-92094 (JP, A) JP-A-54-141349 (JP, A) JP-A-51-18238 (JP, A) JP-A-63-36977 (JP, A) JP-A-51-5246 (JP, A) JP-B-50-3256 (JP, B1) (58) Field surveyed (Int.Cl. ⁶ , DB name) B23K 35/40 B23K 35/02

Claims (2)

(57) [Claims] The steel wire for welding without annealing and plating during wire drawing has a recess having a diameter of 5 to 20 μm,
The amount of Ca adhering to the surface is 5 mg or less per 100 g of wire, and one or more of Na and Ba is 5 mg or less per 100 g of wire on the wire surface in total with the amount of Ca. A steel wire for gas shielded arc welding characterized by being 0.3 to 1.0 g per 10 kg of wire. 2. The steel wire for welding without annealing and plating in the middle of wire drawing has a recess having a diameter of 5 to 20 μm,
The amount of Ca adhering to the surface is 5 mg or less per 100 g of wire, and one or more of Na and Ba is 5 mg or less per 100 g of wire on the wire surface in total with the amount of Ca. 0.3-1.0g per 10kg of wire, tensile strength 90-140kg
A steel wire for gas shielded arc welding characterized by having f / mm ² .