JP2012011461A - Copper-plated solid wire for welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a copper-plated solid wire for welding which enables continuous welding over a long period of time with excellent wire-feeding capability.SOLUTION: The copper-plated solid wire for welding is used for carbon dioxide gas shielded arc welding, and has a lubricant oil and a solid lubricant coated on its surface. Copper powder and iron powder attached to the surface of the copper-plated solid wire for welding have particle sizes not exceeding 20 μm, and are in total at most 0.10g per 10 kg of the copper-plated solid wire for welding. The following are attached to the surface per 10 kg of the copper-plated solid wire for welding: 0.4-2.0g of an animal or plant oil, or a mineral oil as the lubricant oil; and 0.03-0.15g of molybdenum disulfide having a particle size of 0.1-10 μm as the solid lubricant.

Description

  The present invention relates to a copper-plated solid wire for welding used for carbon dioxide shielded arc welding, and is particularly excellent in feedability and enables continuous welding for a long time.

In the field of building steel frames, the gas shielded arc welding method, particularly the carbon dioxide shielded arc welding method using CO ₂ as the shielding gas, is mainly used because of its high efficiency. Previously, most of the gas shielded arc welding methods were manual semi-automatic welding methods, but in recent years, welding robots have been used to reduce costs through labor savings and to further improve welding efficiency through unattended operation at night and on holidays. Automatic welding has also become widespread.

  The welding wire that supports long-term continuous welding by a welding robot is stored in a large-capacity pail pack with a maximum capacity of 500 kg. Only done at the time of exchange. That is, once the welding wire is passed through the welding machine, it is not necessary to pass the tip of the welding wire again until all the welding wires stored in the pail pack are consumed by welding and become empty. Become. Here, the welding wire used for gas shielded arc welding is a solid wire with copper plating on the surface so that it can be fed smoothly, and the welding wire is fed smoothly, that is, wire feeding. Lubricating oil or solid lubricant is applied to the surface to improve feedability. Therefore, in addition to the lubricant, metal powder such as copper powder derived from plating and iron powder derived from the core (steel wire) generated during the production of the welding wire adheres to the surface of the welding wire. Part of the solid matter adhering to the surface of the welding wire adheres to the inside of the conduit liner or power supply tip, and the amount of the solid matter is not changed unless the inside of the conduit liner is manually cleaned and the power supply tip is replaced. Continues to accumulate. As a result, the metal powder and solid lubricant deposited in the power feed tip may fill the clogging with the welding wire and clog it, leading to the stop of feeding the welding wire. Therefore, even when a large amount of welding wire is supplied to the welding robot capable of continuous welding for a long time using a pail pack, automatic welding is stopped before the pail pack is replaced.

  In order to prevent such clogging of metal powder, etc., a welding wire has been proposed in which various lubricants are applied to the surface to reduce frictional resistance, thereby suppressing the generation of metal powder and reducing deposition. Yes. Patent Document 1 discloses that a predetermined amount of at least one of molybdenum disulfide, tungsten disulfide, and tetrafluoroethylene, and one or more fatty acids, esters of mono- or dihydric alcohols of fatty acids, and petroleum waxes on the surface. The applied welding wire is described. In Patent Document 2, a solid lubricant composed of one or more of molybdenum disulfide and boron nitride, potassium compound, copper powder, and wax is applied to the surface, and a lubricant is further applied thereon to form two layers. A copper plating wire for welding provided with a coating layer is described. In Patent Document 3, potassium, molybdenum disulfide, phospholipid, lubricating oil is applied, and the total adhesion amount of solid matter such as potassium and metal powder is 0.30 g or less per 10 kg of the copper plating solid wire for welding. Regulated copper-plated solid wire for welding is described.

JP-A-8-229697 JP 2003-225794 A JP 2008-194716 A

  However, in the techniques described in Patent Documents 1 to 3, in long-time automatic welding that is continuous day and night, metal powder or applied solid lubricant accumulates, and welding wires are fed due to poor conduction. It is insufficient to cope with such welding. Furthermore, Patent Document 3 restricts the amount of solids deposited, but is insufficient for continuous welding for 12 hours, and phospholipids are applied to uniformly disperse molybdenum disulfide on the surface. However, when phospholipid adheres to the copper plating solid wire for welding, copper is easily corroded, and there is a possibility of deterioration of conductivity due to surface oxidation accompanying deterioration with time of the plating film. Therefore, these conventional techniques lack consideration for the wire feeding stop caused by clogging of the power supply tip of the metal powder in the day-and-night continuous robot welding in which the wire feeding is not allowed to stop.

  Further, these technologies have been developed to cope with both the welding wire for spool winding and the welding wire stored in the pail pack. However, a welding wire stored in a pail pack suitable for continuous welding for a long time with a larger capacity further has a problem that the frequency of occurrence of feeding trouble is higher than that of spool winding. Therefore, even if the welding wire by these techniques is stored in a pail pack and used, the effect as in the case of spool winding cannot be obtained sufficiently.

  The present invention has been made in view of the above-mentioned problems, and it is a copper-plated solid wire used by being stored in a pail pack. An object of the present invention is to provide a copper-plated solid wire suitable for improving wire feedability that enables continuous welding for a long time.

  In order to solve the above-mentioned problems, the present inventors have investigated the feeding trouble mechanism in the welding wire stored in the pail pack, and as a result, the following phenomenon has been found. In other words, the welding wire stored in the pail pack has a straight shape without bending due to spool winding, so that the contact pressure between the conduit liner and the power supply tip is weak, and the power supply between the inner surface of the power supply tip and the welding wire is weak. Due to the fact that the contact point easily varies, microchip fusion that occurs when the energization point varies frequently occurs. Therefore, as a result of intensive studies, the present inventors have come to the idea of controlling the amount of solid matter attached to the surface as a welding wire that can further reduce the fusion with the inner surface of the power feed tip.

  That is, the present invention is a copper-plated solid wire for welding used in carbon dioxide shielded arc welding, and the copper powder and iron powder adhering to the surface do not exceed 20 μm in diameter, and the copper-plated solid wire for welding The total amount is not more than 0.10 g per 10 kg, and on the surface, 0.4 kg to 2.0 g of animal or vegetable oil or mineral oil as a lubricating oil and a particle size of 0. 1 to 10 μm molybdenum disulfide: 0.03 to 0.15 g is attached.

  Such copper-plated solid wire for welding is generated by applying lubricating oil to reduce the frictional resistance between the metal conduit liner and the inner surface of the power feed tip, and scraping from the surface of the copper-plated solid wire for welding. Metal powder to be reduced can be reduced. And by applying molybdenum disulfide as a solid lubricant together with the lubricating oil, the fusion with the inner surface of the power supply chip is reduced, the slipping property of the power supply chip is improved, and the inner surface of the power supply chip where metal powder is easily deposited Fusion marks can be reduced. Moreover, an appropriate effect is acquired by regulating the adhesion amount of lubricating oil and molybdenum disulfide. Furthermore, the amount of the metal powder adhering to the surface is inevitably suppressed to a range smaller than the conventional one, so that the wire feeding is not stopped in long-time continuous robot welding day and night.

  According to the copper-plated solid wire for welding according to the present invention, it is used for carbon dioxide shielded arc welding, the slipperiness at the conduit liner and the power feed tip is improved, and the slipperiness is maintained for a long time. Even if stored, microchip fusion is less likely to occur when the energization point fluctuates. As a result, the frequency of occurrence of feeding troubles is reduced, and the welding robot can perform automatic welding for a long time day and night.

It is a flowchart explaining the manufacturing method of the copper plating solid wire for welding which concerns on this invention. It is a partial section perspective view showing typically the structure of a high-pressure water washing device. SEM image of the surface of the copper-plated solid wire for welding and an image of the molybdenum detected from the SEM image by EPMA analysis. (A) and (b) are applied with lubricating oil using an electrostatic coating device In the examples according to the present invention, (c) and (d) are coated with felt.

  Hereinafter, the form for implement | achieving the copper plating solid wire for welding which concerns on this invention (henceforth a copper plating solid wire) is demonstrated.

[Copper-plated solid wire]
The copper-plated solid wire according to the present invention is obtained by applying animal or vegetable oil or mineral oil as a lubricating oil and molybdenum disulfide as a solid lubricant on the surface of a copper-plated solid wire used for carbon dioxide shielded arc welding. . Specifically, the lubricating oil: 0.4 to 2.0 g and molybdenum disulfide having a particle diameter of 0.1 to 10 μm: 0.03 to 0.15 g are attached to the surface per 10 kg of the copper-plated solid wire. It was applied to. Moreover, the copper plating solid wire before applying the lubricating oil and the solid lubricant of the copper plating solid wire according to the present invention (hereinafter, appropriately referred to as pre-coating copper plating solid wire) is the manufacturing process and conveyance thereof. Occasionally, copper powder derived from plating and iron powder derived from interlining are generated and adhered to the surface. In the copper-plated solid wire according to the present invention, these copper powder and iron powder have a diameter (powder diameter) of not more than 20 μm, and the amount of adhesion per 10 kg of the copper-plated solid wire is 0.10 g or less in total. To do. Hereinafter, the deposits on the surface of the copper-plated solid wire according to the present invention will be described.

(Copper powder and iron powder)
As described above, copper powder and iron powder (hereinafter collectively referred to as metal powder) adhere to the surface of the copper-plated solid wire before coating, and these are carried over even after the lubricant and solid lubricant are applied. And continue to adhere. In welding using such a copper-plated solid wire, most of the metal powder passes through the inside of the conduit liner and the power feed chip while being adhered to the surface of the copper-plated solid wire, and is discharged. However, a part of the metal powder is separated from the surface of the copper-plated solid wire and adheres in the conduit liner and the power supply chip, and is deposited in the power supply chip and the like together with the consumption of the copper-plated solid wire. Therefore, if the amount of metal powder adhering to the copper-plated solid wire is large, the deposition rate in the power supply chip or the like is increased, and the feeding length of the copper-plated solid wire until the feeding is stopped is shortened. Specifically, when metal powder (total of copper powder and iron powder) exceeds 10 g per 10 kg of the copper-plated solid wire, continuous welding for a long time becomes difficult. Therefore, it is preferable that the adhesion amount of the metal powder is smaller, and the total amount of copper powder and iron powder adhering to the surface of the copper plating solid wire according to the present invention is 0.10 g or less per 10 kg of the copper plating solid wire for welding. And The adhesion amount of the metal powder can be reduced by washing the pre-application copper-plated solid wire before applying the lubricating oil and the solid lubricant, as will be described later.

  Moreover, if the metal powder having a maximum diameter of more than 20 μm adheres regardless of the amount of adhesion, there is a risk of impeding the conductivity of the power supply chip when passing through the power supply chip. Since the copper powder and iron powder adhering to the surface of the copper-plated solid wire according to the present invention do not exceed 20 μm because they are not easily discharged from the chip and easily adhere to and accumulate inside. Such coarse metal powder is generated as plating residue when the copper plating solid wire before coating is not good in adhesion of copper plating, and remains on the surface.

(Lubricant)
The copper-plated solid wire according to the present invention applies animal oil, vegetable oil or a mixture thereof (hereinafter collectively animal and vegetable oil), or mineral oil or synthetic oil (hereinafter collectively mineral oil) as a lubricating oil. Specific examples of animal and vegetable oils include palm oil, rapeseed oil, castor oil, lard, and beef tallow. Mineral oil contains paraffinic hydrocarbons and naphthenic hydrocarbons commonly used as lubricating oils. And those made of refined petroleum products. These oils have the effect of reducing the frictional resistance between metals. The animal or vegetable oil or mineral oil is applied as a lubricant to the surface of the copper-plated solid wire in a state in which the particles of molybdenum disulfide described below are mixed. When contacting with the inner surface of the metal, it is possible to suppress generation of metal powder by scraping the surface. When the amount of adhesion of the lubricating oil on the surface of the copper-plated solid wire per 10 kg is less than 0.4 g, the above effect cannot be obtained, so the wire feedability is low, and a large amount of spatter is generated immediately after the start of welding. As a result, the arc length fluctuates frequently, and spatter may adhere to the inside of the power supply tip and stop feeding. On the other hand, when the adhesion amount exceeds 2.0 g, the lubricating oil forms a sump in the power supply tip in continuous welding, and this lubricating oil periodically leaks from the tip of the power supply tip. It falls to the weld bead and a healthy weld metal cannot be obtained. Further, if the amount of lubricant applied becomes excessive, the copper-plated solid wire slips on the feeding roller and stable feeding cannot be performed. Therefore, the lubricating oil adhering to the surface of the copper-plated solid wire according to the present invention is 0.4 g or more and 2.0 g or less per 10 kg of the copper-plated solid wire for welding. Since mineral oil has a smaller friction reducing effect than animal and vegetable oils, when applied to lubricating oil, the amount of adhesion per 10 kg of copper plating solid wire for welding is preferably 0.8 g or more, and more preferably 0.85 g or more. . Further, since mineral oil is less likely to evaporate due to arc heat than animal and vegetable oils, when applied to lubricating oil, the amount of adhesion is preferably 1.0 g or less.

(Molybdenum disulfide)
The commonly used molybdenum disulfide (MoS ₂ ) is applied to the copper-plated solid wire according to the present invention as a solid lubricant. Molybdenum disulfide has the effect of reducing the adhesion of the copper-plated solid wire to the inner surface of the power supply tip, so it improves the slipperiness of the power supply tip, and metal powder is selectively used for the fusing marks on the inner surface of the power supply tip. However, it is possible to reduce the deposition of the metal powder in the power feed tip by reducing the fusion marks. When molybdenum disulfide has an adhesion amount on the surface of 10 kg of copper-plated solid wire of less than 0.03 g, the above effect cannot be obtained sufficiently. On the other hand, since molybdenum disulfide is a solid material like the metal powder, a part of the molybdenum disulfide is deposited and adhered to the inside of the conduit liner and the power supply tip away from the surface of the copper-plated solid wire. If the number increases, the supply will stop. Specifically, when the adhesion amount exceeds 0.15 g, long-time continuous welding becomes difficult. Therefore, the molybdenum disulfide adhering to the surface of the copper-plated solid wire according to the present invention is 0.03 g or more and 0.15 g or less per 10 kg of the copper-plated solid wire for welding. Molybdenum disulfide is applied to the surface of the copper-plated solid wire in a state of being mixed with the lubricating oil, and the amount of adhesion can be controlled by adjusting the mixing ratio. Specifically, 4 to 10% is preferable by mass ratio with respect to the lubricating oil. With this mixing ratio, it is easy to obtain an appropriate adhesion amount for both the lubricating oil and molybdenum disulfide when applied by the electrostatic coating method described later.

  Molybdenum disulfide is applied so as to adhere uniformly to the surface of the copper-plated solid wire. If there is a bias in the amount of adhesion, molybdenum disulfide adheres to the inside of the power feed chip from a portion where the surface of the copper-plated solid wire is large, and melts in the power feed tip at a location where there is little. In the present invention, in order to uniformly deposit molybdenum disulfide, the mixture with the lubricating oil is applied to the surface of the copper-plated solid wire by an electrostatic coating method as will be described later.

  As described above, molybdenum disulfide is a solid material, and in the present invention, a granular material is applied. However, when the diameter is large, specifically, when it exceeds 10 μm, power is supplied as a coarse solid material during welding. Increase the amount of deposition in the chip. On the other hand, if the particle size of molybdenum disulfide is less than 0.1 μm, the viscosity of the mixture increases when mixed with lubricating oil to be applied to the surface of the copper-plated solid wire. The fluidity of the liquid is reduced, and the discharge amount of the molybdenum disulfide and lubricating oil by the coating device becomes unstable. Therefore, molybdenum disulfide having a particle size of 0.1 μm or more and 10 μm or less is used. Molybdenum disulfide having such a particle diameter is obtained by pulverizing with a mill, for example.

The amount of metal powder (copper powder, iron powder) and molybdenum disulfide adhering to the surface of the copper-plated solid wire can be measured, for example, by the following method. Cut about 1 to 10 kg of copper-plated solid wire so that it is not touched, measure the mass, and then wash with an organic solvent such as ethanol, acetone, normal paraffin, or petroleum ether, and dry the organic solvent used for this washing. Filter with a filter paper and measure the mass of the residue. Specifically, after filtering with a filter paper whose mass has been measured in advance, the mass increase obtained by drying the filter paper and measuring the mass again becomes the mass of the residue. The mass of the residue is the sum of the metal powder and molybdenum disulfide. Therefore, the residue attached to the filter paper is quantitatively analyzed with an energy dispersive X-ray fluorescence spectrometer (EDX), and the mass ratio of copper powder (Cu), iron powder (Fe), and molybdenum disulfide (MoS ₂ ). Is calculated by converting the mass of the residue. Or molybdenum disulfide is melt | dissolved by the sulfuric acid white smoke process from the filter paper to which the residue adhered, and this solution is quantitatively analyzed by atomic absorption method, the mass of molybdenum (Mo) is calculated | required, and it converts into the mass of molybdenum disulfide. The mass of the metal powder (total of copper powder and iron powder) is calculated by subtracting the mass of molybdenum disulfide from the mass of the residue. By converting these masses per 10 kg by the mass of the cut copper plating solid wire, the respective masses of the metal powder and molybdenum disulfide adhering to the surface of the copper plating solid wire can be obtained.

  The size of the metal powder (copper powder, iron powder) and molybdenum disulfide adhering to the surface of the copper-plated solid wire can be determined by observing the residue adhering to the filter paper with a scanning electron microscope (SEM). it can. Or you may observe the surface of a copper plating solid wire directly by SEM. However, as shown in FIG. 3A, copper powder, iron powder, and molybdenum disulfide all appear black in the SEM image. Therefore, it is possible to identify solids by simultaneously performing surface analysis with an electron beam microanalyzer (EPMA). For example, a solid that matches the detection position of molybdenum can be identified as molybdenum disulfide. In addition, when the surface of the copper-plated solid wire is directly observed, molybdenum disulfide appears white and the distribution state can be observed as shown in FIG.

The amount of lubricating oil adhering to the surface of the copper-plated solid wire can also be measured by cutting out the copper-plated solid wire and measuring its mass, followed by washing with a solvent, as in the case of the solid material. Specifically, it is washed with carbon tetrachloride (CCl ₄ ), and this washing solution is quantitatively analyzed by infrared absorption spectroscopy (IR) to obtain the mass, and converted to the mass of the cut copper plating solid wire per 10 kg. By doing so, the mass of the lubricating oil adhering to the surface of the copper plating solid wire can be obtained.

[Manufacturing method of copper-plated solid wire]
As the copper-plated solid wire before coating, a known copper-plated solid wire used for carbon dioxide shielded arc welding can be applied, and JIS-specified copper-plated solid wires such as JIS Z3312 YGW18 and YGW11 can be applied. Such a pre-coating copper-plated solid wire can be produced by a known method, and as shown in FIG. 1, a wire made of a steel material having a predetermined component is stretched with annealing in the middle as necessary (not shown). After the wire is coated and coated with copper, it is further drawn to obtain a product diameter.

  Since the wire-drawing lubricant and metal powder adhere to the surface of the pre-coating copper-plated solid wire, it is washed to remove them. As a cleaning method, it is desirable in production to use a cleaning device that allows the pre-coating copper-plated solid wire to pass in-line. As an example, an immersion hot water bath immersed in water having a water temperature of 50 ° C. or higher for a predetermined time, a high-pressure liquid breathing pressure of 0.3 to 0.5 MPa for removing attached water, a temperature of 80 to 100 ° C., a pressure of 0 A high-pressure steam cleaning apparatus having a high pressure of 1 to 0.5 MPa, a high-temperature water cleaning apparatus having a water temperature of 40 ° C. or higher, and a pressure of 8 to 12 MPa are serially passed through the copper-plated solid wire before coating in this order. As shown in FIG. 2, the high-pressure water washing apparatus is a device in which a copper-plated solid wire before coating passes further inside the inner pipe of the double pipe structure, and the water is placed between the outer pipe and the inner pipe of the double pipe structure. Is supplied by a pump, and high-pressure water is sprayed from a large number of nozzles formed in the inner pipe toward the copper-plated solid wire before coating. The passing speed of the pre-coating copper-plated solid wire in the cleaning apparatus is set according to the size of the apparatus. Further, a cavitation device may be added to these devices to directly or indirectly vibrate the pre-coating copper-plated solid wire.

  Animal and vegetable oils or mineral oils are mixed as a lubricating oil, and molybdenum disulfide is mixed as a solid lubricant, and the mixture is applied to a cleaned pre-application copper-plated solid wire. Here, it is desirable to apply an electrostatic coating method as a method of applying a mixture of lubricating oil and molybdenum disulfide. According to the electrostatic coating method, it is applied while maintaining the concentration of molybdenum disulfide in the mixture, so that molybdenum disulfide is evenly distributed on the surface of the copper-plated solid wire, rather than coating with a coating medium such as a brush or felt. Easy to adhere. According to a brush or the like, it is particularly difficult to make it uniform in the circumferential direction of the surface of the copper-plated solid wire. Below, an example of the coating method using an electrostatic coating apparatus is demonstrated.

  Lubricating oil in which molybdenum disulfide having a predetermined particle diameter is mixed at a mass ratio of 4 to 10% in a mixing storage tank is supplied to the electrostatic coating apparatus by a metering pump. In an electrostatic coating device, a pre-application copper-plated solid wire, which is the object to be coated, is set as the positive electrode, and the ejection portion of the electrostatic coating device is set as the negative electrode. Form. When the mixture of the lubricating oil is atomized and ejected from the ejection part, the mixture is negatively charged by the ejection part of the electrostatic coating device as a negative electrode, so that it is coated at a constant ratio via an electric field gradient in the atmosphere. It adheres by being adsorbed by an object. By using such an electrostatic coating apparatus, molybdenum disulfide with respect to the lubricating oil substantially matches the mixing ratio in the mixing storage tank with respect to the amount of adhesion to the surface of the copper plating solid wire.

  The surface of the copper-plated solid wire thus obtained was solid as shown in the SEM image photograph (FIG. 3 (a)) and the image photograph (FIG. 3 (b)) in which molybdenum was detected by EPMA analysis. The distribution of the material, particularly molybdenum disulfide, becomes uniform. On the other hand, when the same mixture is applied as a coating medium with felt, as shown in FIGS. 3C and 3D, the solid matter is unevenly distributed along the length of the copper-plated solid wire. It is likely to occur. In particular, as shown in FIG. 3D, the uniformity of the distribution of molybdenum disulfide is lowered, and there is a possibility that the amount of adhesion locally falls outside the scope of the present invention.

  Thus, by using an electrostatic coating apparatus, molybdenum disulfide adheres uniformly to the surface of the copper-plated solid wire. As described above, the amount of adhesion almost coincides with the mixing ratio in the mixing storage tank, and can be easily controlled by the mixing ratio and the coating amount with respect to the lubricating oil. The copper-plated solid wire according to the present invention obtained by the above method is wound and stored in a pail pack.

  As mentioned above, although the form for implementing this invention has been described, the Example which confirmed the effect of this invention is demonstrated concretely compared with the comparative example which does not satisfy | fill the requirements of this invention below. In addition, this invention is not limited to this Example.

[Sample preparation]
A copper-plated solid wire having a diameter of 1.2 mm that conforms to the standard of JIS Z3312 YGW18 used for carbon dioxide shielded arc welding was cleaned with an in-line type cleaning device under the following conditions.
(Cleaning conditions)
Device passing speed: 400 to 1000 m / min
Immersion bath temperature: 40-100 ° C
Liquid cutting air breath pressure: 0.1-1.0 MPa
Steam cleaning device temperature: 80 to 200 ° C., pressure: 0.1 to 1.0 MPa
High pressure water washer water temperature: 40-80 ° C, pressure: 5-30MPa

  Molybdenum disulfide particles were mixed with the lubricating oil at a mass mixing ratio shown in Table 1. The mixture was applied to the washed copper-plated solid wire by changing the coating amount with an electrostatic coating apparatus to obtain a test material (wire Nos. 1 to 23) for the copper-plated solid wire. In addition, palm oil was used as animal and vegetable oil, and polybutene synthetic oil was used as mineral oil. In addition, wire No. 22 is a comparative example in which 10% by mass of phospholipid is mixed based on palm oil.

(Measurement of solid matter attached to the surface)
About 1 to 10 kg of the produced copper-plated solid wire was cut out so as not to touch the hands, and the mass was measured. Then, the mass was washed with normal paraffin, and this washing solution was filtered with dry filter paper, and the mass of the residue was measured. Further, the residue adhering to the filter paper is quantitatively analyzed with an energy dispersive X-ray fluorescence spectrometer (EDX), and the mass ratio of copper powder (Cu), iron powder (Fe), and molybdenum disulfide (MoS ₂ ). Each of the masses was calculated in terms of the mass of the residue. For the metal powder (total of copper powder and iron powder) and molybdenum disulfide, the calculated mass is converted per 10 kg by the mass of the cut copper plating solid wire, and is shown in Table 1. Moreover, about the residue adhering to the said filter paper, it observed by 400 time with a scanning electron microscope (SEM), the diameter of metal powder (copper powder, iron powder) was measured, and distribution range is shown in Table 1. Furthermore, molybdenum disulfide is dissolved by white smoke treatment from the filter paper to which the residue is attached, and the solution is quantitatively analyzed by atomic absorption method to determine the mass of molybdenum (Mo), which is converted to the mass of molybdenum disulfide, Further, the mass of the metal powder (total of copper powder and iron powder) was calculated by subtracting this mass from the mass of the residue. These masses almost coincided with the masses determined by the EDX.

  The surface of the copper-plated solid wire is observed with a SEM at a magnification of 400, and at the same time, the solid is identified by performing surface analysis with an electron beam microanalyzer (EPMA). The particle size of molybdenum sulfide was measured, and the distribution range is shown in Table 1. Further, the distribution state of molybdenum disulfide on the surface of the copper-plated solid wire was observed. Fig. 3 (a) shows a SEM image of the surface (copper powder, iron powder, molybdenum disulfide) in Fig. 3. Fig. 3 (a) shows a photograph of molybdenum detected by EPMA analysis (white image). Fig. 3 (b) shows the molybdenum disulfide.

(Measurement of lubricant adhering to the surface)
Cut out about 1-10kg of the prepared copper-plated solid wire so as not to touch it, measure its mass, and then wash with carbon tetrachloride (CCl ₄ ). The mass was determined with the applied oil concentration meter. This mass is converted per 10 kg by the mass of the copper-plated solid wire cut out and shown in Table 1.

[Evaluation]
As a welding test, with a welding robot equipped with a water-cooled straight torch, using the prepared copper-plated solid wire, the distance between the power supply tip and the welding base material (steel plate) was set to 30 mm, and CO ₂ was supplied as the shielding gas. Downward bead-on-plate welding was performed at a current of 340 to 370 A and a voltage of 37 to 40V. The feeding path was arranged so that the feeding resistance of the copper-plated solid wire was about 2.5 times that in a normal welding robot. By adopting such a severe feeding route, this welding test was an accelerated test in which the welding time was 6 hours and the continuous welding time in normal welding was equivalent to more than 12 hours. That is, the welding test is continuously performed for 6 hours at the longest, and for the specimens that are not weldable due to the stop of feeding of the copper-plated solid wire before 6 hours elapse, the welding stop time is shown in Table 1 as the continuous welding time. .

  Table 1 shows the solid deposition rate calculated from the continuous welding time after measuring the mass of the deposit in the power feed tip as the solid deposition amount after the welding test. For the specimens that could not be continuously welded for 6 hours, the inside of the power supply tip was visually observed. If the feed stop was due to clogging of the deposit, the power supply tip was clogged, and the others were “○”. As shown in Table 1. Further, Table 1 shows “◯” when the copper-plated solid wire is not fused, “Δ” when micro-fusion is generated, and “X” when fusion is generated.

  A test material that can be continuously welded for 6 hours and that there was no abnormality in the welded part or the like is shown in Table 1 with a comprehensive evaluation of “○”, and “△” indicates that a slight abnormality occurred, and the continuous welding time Table 3 also shows “Δ” for 3 hours or more and less than 6 hours. The continuous welding time of less than 3 hr is indicated by “x” in Table 1.

  As shown in Table 1, the wire No. 1 to 8 are examples in which the diameter and amount of the metal powder remaining on the surface, the amount of the lubricant oil applied and adhered, and the particle size and amount of molybdenum disulfide are all within the scope of the present invention. Since the deposition rate of the solid matter inside was as low as less than 4 mg / hr, the feed was not stopped by continuous welding for 6 hr, and there was no abnormality in the welded portion. Furthermore, as shown in FIGS. 3 (a) and 3 (b), the surface of the copper-plated solid wire of the example according to the present invention has a distribution of solid matter, particularly molybdenum disulfide, as shown in FIGS. Since it is uniform and is in such an adhesion state, the effect of molybdenum disulfide becomes appropriate, and good wire feedability can be maintained for a long time.

(Evaluation by remaining metal powder)
On the other hand, the wire No. In Nos. 17 to 20, since washing before application is insufficient and the amount of metal powder adhering is excessive, even if lubricating oil or the like is within the scope of the present invention, any metal powder accumulates in the power supply chip and clogs the power supply chip. The feed was stopped in less than 6 hours. In addition, wire No. No. 21 is a comparative example in which coarse metal powder adhered to the copper-plated solid wire before coating by relaxing the activation treatment before the plating. For this reason, the amount of metal powder adhering is within the scope of the present invention, but the coarse metal powder is not discharged from the power supply chip and adheres to the inside to further deposit subsequent solids. Feeding was stopped in a shorter time than the comparative example with an excessive amount of adhesion. In addition, this coarse metal powder hindered the electrical conductivity between the power feed tip and the copper-plated solid wire, resulting in frequent arc instability.

(Evaluation with lubricating oil)
Wire No. Nos. 11 and 15 were insufficient in the amount of lubricant applied, so that the wire feeding performance was lowered, and the wire feeding was stopped even in a state where there was little accumulation of solid matter in the power feed tip. On the other hand, wire No. Nos. 12 and 16 were capable of continuous welding for 6 hours because the amount of lubricant applied was excessive, but during welding, oil droplets dropped from the tip of the power feed tip onto the molten metal on the weld base metal, resulting in a weld bead. Blow holes were formed at several locations. In addition, wire No. 22 is a comparative example in which phospholipid was added to palm oil as a lubricating oil, and the amount of phospholipid deposited was about 0.08 g. Since this phospholipid corroded the copper of the copper-plated solid wire, the corroded copper hindered the current-carrying power of the power supply tip, causing arc instability immediately after the start of welding, leading to the stop of feeding, and discoloration on the surface Was observed.

(Evaluation with solid lubricant)
Wire No. In Nos. 9 and 13, since the adhesion amount of molybdenum disulfide was insufficient, minute fusion to the power supply chip occurred and the supply was stopped. Furthermore, metal powder (mainly copper powder) easily accumulates on the minute fusion marks generated in the power supply chip, and the solid matter accumulated in the power supply chip increases before the supply is stopped. On the other hand, wire No. In Nos. 10 and 14, since the adhering amount of molybdenum disulfide was excessive, molybdenum disulfide acting as a lubricant was deposited in the power supply tip beyond the allowable limit of continuous welding, and the supply was stopped. In addition, wire No. No. 23 is a comparative example using molybdenum disulfide having an excessively large particle size. Since the particle size of molybdenum disulfide is as large as that of the metal powder, it was deposited in the power supply chip as a solid material like the metal powder. As a result, the power supply chip was clogged in a short time and the supply was stopped, and a large amount of molybdenum disulfide having a large particle size was deposited in the power supply chip together with the metal powder.

Claims (1)

A copper-plated solid wire for welding used in carbon dioxide shielded arc welding,
The copper powder and iron powder adhering to the surface do not exceed 20 μm in diameter, and the total is 0.10 g or less per 10 kg of the copper plating solid wire for welding,
On the surface, per 10 kg of the copper plating solid wire for welding, animal or vegetable oil or mineral oil: 0.4 to 2.0 g as a lubricating oil, and molybdenum disulfide having a particle diameter of 0.1 to 10 μm as a solid lubricant: 0. A copper-plated solid wire for welding, characterized in that 03 to 0.15 g is adhered.