JPS6032560B2 - Manufacturing method of welding wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a welding wire used in automatic welding, and in particular to its surface treatment.
The purpose is to perform surface treatment with excellent rust resistance and electrical conductivity.

The automatic welding wires used in C02 arc welding are currently mainly solid wires coated with steel plating, but recently copper-plated coatings have been used to prevent harmful welding fumes caused by copper-plated coatings. Various surface treatment methods have been studied in place of surface treatment, and some are beginning to be commercially available.

In addition, recently, flux-cored wire (composite wire), which has a softer arc and better bead appearance than solid wire, has begun to be put into practical use, but this wire also has a surface treatment that replaces copper plating. Lubricated and rust-resistant treated. FIG. 1 shows a conventional copper-plated solid wire. In the figure, 1 is a solid wire and 2 is a copper-plated wire.

Further, FIG. 2 shows a conventional lubricant film treated flux cored wire, in which 3 is a flux, 4 is a metal jacket, and 5 is a MoS2 lubricant film. By the way, wire for automatic welding is normally fed through a wire guide tube called a conduit tube and powered by the tip at the tip of the welding torch, but in this case the surface of the wire may be scraped due to frictional resistance in the conduit tube. Therefore, the surface must have adequate lubricity.

In addition, appropriate current carrying performance is required for stable power supply at the tip of the torch. In other words, wire for automatic welding requires surface treatment that has appropriate lubrication performance, current conductivity performance, and rust resistance during storage due to its usage characteristics, and copper glazing treatment and MoS2 lubricant film treatment are suitable for these purposes. The surface treatment took this into consideration. However, when copper plating is subjected to welding, the metal fumes may cause pollution diseases such as hemorrhagic gastritis, so various alternative surface treatment methods are being considered. MoS2 lubricant film treatment was also implemented as one of the methods, as in the case of flux cordwires. However, this MoS
2 Lubricating film treatment is superior to copper plating treatment in terms of lubricity, but in terms of electrical conductivity on the chip, MoS
Because 2 is non-conducting, it is causing a current-conducting failure,
It was extremely difficult to use, as it caused arc instability and wire fusion due to arcing between the chip and the wire.

As a result of various experiments and studies, the inventors of the present invention have previously developed a welding wire in which semiconductive graphite powder is adhered to the surface of the wire.

This wire can improve both electrical conductivity and lubricity. In the laboratory, it has been confirmed that wires made by rubbing solid graphite onto the wire surface over and over again have almost satisfactory electrical conductivity and lubrication performance. For practical production, the method of fixing graphite is to mix graphite powder with MoS2 etc. in a wire drawing lubricant, draw the wire at a relatively low area reduction rate, and fix it using the pressure inside the die during wire drawing. We believe that this is a good idea, and have been proceeding with development in this regard. However, with this method, iron powder, which is wire scrapings generated during wire drawing, is also adhered to the wire surface at the same time as graphite, and for this reason, when continuous welding is performed for a long time,
It has been found that iron powder accumulates in the conduit tube and chip, which can aggregate and cause wire feeding and current flow in the chip to be inhibited.

Therefore, as a result of further experiments and studies, the inventors of the present invention found that as a method for fixing graphite, the surface of the wire is subjected to pickling, blasting, or chemical conversion treatment in advance to give a glossy surface after the final finishing wire drawing. They discovered that by making the material have fine irregularities and then pressing it with a roller in powdered graphite, it was possible to firmly adhere a large amount of graphite without iron powder sticking.

Figure 3a shows the glossy surface after the final finishing wire drawing, and Figure 3b shows the crystal film formula of the surface after the satin finish treatment, where 6 is the crystal, 7 is the glossy surface, and 8 is the satin finish surface. .

As shown in FIGS. 3a and 3b, the satin finish treatment as a base treatment increases the unevenness of the grain boundaries, and the powdered graphite is held in the concave portions, so that a large amount of graphite can be firmly attached.

4 and 5 show welding wires according to embodiments of the present invention, the embodiment shown in FIG. 4 is used for solid wire, and the embodiment shown in FIG. , when used in a flux-cored wire, and in the figure, 9 is powdered graphite.

Fig. 6 shows the steps in carrying out the method of the present invention, and Fig. 7 shows the main steps. 13 is a hot air drying process, 14 is a preliminary adhesion process using colloidal graphite 14a, and 15 is an adhesion process using graphite powder 15a.
6, the graphite powder 15a is compressed and adhered to the wire 10'.

Further, 16 is a guide roller, and 17 is felt. As is clear from this process, in the present invention, the high pressure that is applied when the surface is destroyed by a die is not applied, so the wire surface is not scraped and there is no generation of iron powder.

That is, a large amount of graphite powder is fixed to the concave portion of the torn surface by light roller pressure. Furthermore, if colloidal graphite kneaded with a solvent is preliminarily deposited as in the preliminary deposition step, and then powdered graphite is pressed with a roller, the above-mentioned results can be made more effective.

Figure 8 shows the results of an investigation into the feedability of the solid wire manufactured by the manufacturing method of the present invention (characteristics A), conventional copper wires (characteristics B), and conventional flux cored wires (frame characteristics C). As is clear from Figure 8,
The wire obtained according to the present invention has better lubricity than conventional copper cladding and requires less load current to be applied to the outside of the feed motor.

In addition, FIG. 9 shows a comparison of the tip wear characteristics of the same wire as in FIG. 8, and as is clear from FIG. Because of its superior electrical conductivity and the fact that it is less likely to form welds, wear is significantly lower than that of conventional materials. Furthermore, the following table shows the amount of deposits on the wire surface in the manufacturing method of the present invention.As can be seen from this table, in the present invention, the amount of graphite deposited is larger than that in the method of fixing with a die, and the deposits are The amount of iron powder inside is small. As shown in the table above, according to the manufacturing method of the present invention, it is possible to obtain a welding wire that has much better feedability and lubricity than conventional wires, and also has a certain level of rust resistance and practical performance. As a result, it is possible to have characteristics that do not cause harmful fumes or current flow inhibition, and it is possible to further accelerate the spread of welding wires.

[Brief explanation of the drawing]

Figures 1 and 2 are cross-sectional views showing conventional welding wires, respectively, and Figures 3a and 3b are crystal film diagrams showing the glossy surface of the welding wire after final drawing and the surface after satin finish treatment. ,
4 and 5 are cross-sectional views showing a welding wire obtained by the manufacturing method of the present invention, FIG. 6 is a schematic diagram showing the manufacturing process in the manufacturing method of a welding wire of the present invention, and FIG. A schematic diagram showing the main steps in the manufacturing process, and FIGS. 8 and 9 are characteristic diagrams for explaining the effects of the manufacturing method of the present invention, respectively. 9... Powder graphite, 10... Wire, 11... Pickling, chemical conversion treatment step, 15...
...Adhesion step, 15a...Graphite powder. Figure 1 Figure 2 Figure 3 Figure 6 Figure 4 Figure 5 Figure 7 Figure 8 Figure 9

Claims (1)

[Claims] 1. A method for manufacturing a welding wire without a copper plating coating, which is characterized in that after finishing wire drawing, the surface of the wire is treated with a satin finish by pickling, etc., and then the graphite is crimped with a roller in powdered graphite. Method of manufacturing wire.