JPS5913956B2 - welding wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The object of the present invention is to obtain at a low cost a welding wire that is excellent in various performances such as welding performance, current carrying performance, and rust prevention performance.

Conventionally, welding wires used in automatic and semi-automatic welding in a protective atmosphere such as carbon dioxide gas or argon gas have generally had copper plating on their surfaces.

In addition, if we take as an example a solid wire for steel welding among conventional welding wires, this solid wire is usually made of Si or M
A 5.5 mm diameter steel wire called a raw wire containing a specified amount of alloying elements such as n is subjected to treatments such as pickling, wire drawing, and sintering, and then copper plating is applied to the surface to a specified thickness. 6mTn
Practically necessary wire diameters such as φ and 1.2nφ were used to obtain various welding performances. By the way, this copper plating is applied to the surface of the welding wire for the purpose of improving the electrical conductivity from the power source to the wire during welding and the rust resistance of the wire.

Particularly in automatic and semi-automatic welding in a gas-protected atmosphere, a wire diameter of 2.0 mm or less is commonly used, and the wire feeding speed during welding is very fast. Therefore, the conductivity and feedability of the wire at the current-carrying portion at the tip of the torch are extremely important factors in obtaining satisfactory welding results. However, conventional copper plating has the following 20 drawbacks. In other words, (1) in terms of weldability, 4. Since copper plating is usually done by electroplating, there is a phenomenon in which hydrogen generated during the plating process penetrates into the wire, and this is especially true when hydrogen is sensitive. When welding high-strength steel, it may cause hydrogen cracking or embrittlement in the weld.

□ Plated copper tends to accumulate in the weld metal, which can lead to high temperature cracks in the weld and deterioration of mechanical properties.

During 303 welding, the welding wire is normally fed to the welding area through a passage called a conduit tube, but at this time, due to frictional contact between the surface of the wire and the inner surface of the conduit tube, the copper plating falls off and falls into the conduit tube. Accumulation can impair wire feedability and inhibit good welding results.

(2) In terms of productivity, in order to apply copper plating, the wire surface must be cleaned by pickling or electrolytic pickling after wire drawing, and then plating such as cyanide copper plating or copper sulfate plating is applied. Since we apply
Large equipment and costs are required for the pretreatment of the dust and the treatment of the dust and its waste liquid.

Moreover, with the recent strong desire to reduce welding costs, welding wires without copper plating are gradually being put into practical use in Japan.

However, this wire without copper plating has the following drawbacks. In other words, when welding with this wire for a long time, the wear of the feeder, usually called a chip, which supplies the welding current to the wire, is significantly greater than with conventional copper-plated wire, and the rust resistance of copper-plated wire during storage is lower. It is inferior. In other words, the chip is generally made of copper or copper alloy and has a hole slightly larger than the diameter of the wire, but it is placed at the tip of the welding torch and feeds power to the wire while passing the wire through it. Long time: The hole becomes worn and enlarged due to welding in between, making the power supply to the wire unstable. Moreover, it often happens that good welding results cannot be obtained. In addition, since tips are normally used as consumables, wear of tips increases welding costs, which greatly hinders the practical use of wires without copper plating. Therefore, in order to eliminate the drawbacks of such wires without copper plating, the present inventors first proposed
Although we have provided a steel wire for welding as shown in Publication No. 6247, its effectiveness is lower than that of copper when welding in a high current range of 300 A or more or using a wire with a wire tensile strength of 100 k9/ml or more. It was not strong enough to compete with plated wire. In addition, surface treatment methods such as those found in Japanese Patent Publication No. 51-4503 have been proposed, but the amount of chip wear during welding and rust prevention during storage are not as good as replacing copper plating. At present, it seems that we are far from being able to promote the practical use of welding wire without copper plating. Therefore, the present inventors solved the drawback that the amount of tip wear during welding of a welding wire without copper plating is significantly greater than that of a welding wire with copper plating, and promoted the practical use of such a wire. As a result of various studies, we have found that a mixture of powdered sulfur and graphite, which has been thought to cause harm such as weld cracks, if it gets into the welded metal on the wire surface after wire drawing. It has been found that by applying an appropriate amount of this material, the amount of chip wear during welding can be significantly reduced.

Moreover, by applying a rust-preventing lubricant containing organic metals, it is possible to further reduce the amount of wear on the chips, and the rust resistance for long-term storage is significantly higher than that of copper-plated wire. I was able to improve it.
In other words, sulfur is an easily available extreme pressure additive that is applied to various lubricants, and in the wire manufacturing process, it is used as a wire drawing lubricant to extend the life of practical dies, that is, to reduce die wear under high temperature and high pressure. It's helpful to let you know.

If a large amount of this powdered sulfur is applied to the wire surface after wire drawing, the amount of chip wear during welding can be sufficiently reduced compared to copper-plated wire, even without copper plating. However, since sulfur is originally an electrical insulating substance, a large amount of sulfur attached inhibits the conductivity of the wire surface, and arc instability is likely to occur during welding. Moreover, as described above, when sulfur enters the weld metal, welding cracks called grain boundary cracks are likely to occur, which naturally limits the amount of sulfur applied. Therefore, as a result of various experiments, sulfur was added to a wire unit surface area of 0.0059 or more 0.0.
It has been found that by applying less than 19% of sulfur, the amount of chip wear can be reduced without causing grain boundary cracking, as is clear from the relationship between the amount of sulfur applied and the cracking rate shown in FIG.

However, since sulfur is an electrically insulating substance, if even a small amount of sulfur is added to the wire surface, the welding wire cannot have sufficient electrical conductivity. This conductive surface is covered with conductive graphite, and by applying a mixture of graphite and sulfur to the surface of the wire after wire drawing, it is possible to Even when the amount of copper plating is small, the amount of chip wear is less than that of a copper-plated wire, and the current conductivity is also sufficiently satisfactory, as is clear from the arc start time shown in FIG. Figure 2 shows the arc start times when welding conditions are changed for sample wires A, B, and C with a wire diameter of 1.2 mTILφ. Sample wire A is a conventional copper-plated wire, and sample wire B is a sulfur-plated wire. Copper coated with 0.005 to 0.19/ml of graphite, 0.01 to 1.09/ml of graphite, and 0.05 to 0.59/ml of anticorrosion lubricating oil containing organic metal. Wire without plating, sample wire C has 0 sulfur.
．． This is a wire without copper plating coated with a coating weight of 1 to 1.09/I, and each plotted point is the average value of 20 measurements. Further, the coating amount of graphite is preferably 0.019 or more and less than 1.09 per 1 m1 of wire unit surface area.

If the coating amount is less than 0.01, there is no effect of improving conductivity, and if it is more than 1.09, there is a risk of weld cracking due to carburization of the deposited metal. It's for a reason. Furthermore, it is desirable that the amount of sulfur and graphite to be applied is as small as possible from the viewpoint of welding workability. As explained above, by applying an appropriate amount of a mixture of powdered sulfur and graphite to the wire surface after wire drawing, welding that is actually superior to copper-plated wire even without copper plating can be achieved. performance can be obtained.

By the way, in actual production, a fairly sophisticated production technology is required to uniformly apply powdered sulfur and graphite to the wire surface in as small a quantity as possible.

Furthermore, simply applying an appropriate amount of powdered sulfur and graphite does not provide sufficient rust resistance to withstand long-term storage. As a result of studies to solve this problem, we found that rust-preventing lubricants, especially metal di-thio phosphates and metal di-thio carbamates represented by the structural formula shown below, such as zinc di-thio phosphate, 1.0% of organic metals such as
It has been found that it is sufficient to apply a rust-preventing lubricant containing less than 10% of the above amount.

(Metal di-thio phosphate) M: Zn, Ag, C
By applying metal elements such as u, Pb, MO, and Sb together with such rust-preventing lubricants, the rust resistance is good as shown in Table 2 below, and the sulfur content is reduced as shown in Table 1 above. Despite the non-uniform application of the mixture of sulfur and graphite, it is possible to industrially easily obtain a welding wire that exhibits less tip wear during welding than when only the mixture of sulfur and graphite is applied.

By applying an appropriate amount of a mixture of sulfur and graphite and a rust-preventing lubricant containing organic metals as described above,
The anti-friction effect of sulfur, the electrical conductivity effect of graphite, the anti-friction effect due to the decomposition of organic metals at high temperatures during welding of anti-rust lubricating oil containing organic metals, and the original anti-rust effect can be obtained. Even without this process, it is possible to easily produce a welding wire that has better welding performance than conventional copper-plated wire, that is, has less chip wear, excellent current conductivity, and rust resistance.

Incidentally, such effects of the present invention are not limited to solid welding wires that are not copper-plated, but can be similarly obtained with welding composite wires that are originally not copper-plated.

As described above, the welding wire of the present invention has the following great effects.

That is, in terms of welding requirements, the amount of chip wear during welding is smaller than that of copper-plated wire, and welding costs can be reduced.

2. Due to the effect of anti-rust lubricating oil, it is less likely to rust than copper-plated wire during long-term storage.

3 Compared to when only conventional anti-corrosion lubricant is applied, the amount of chip wear is less than that of copper-plated wire, even when welding in a higher current range or using wire with higher wire tensile strength. Therefore, the widespread practical use of wires without copper plating can be promoted.

4 A part of the copper plating of conventional copper-plated wire burns during welding and becomes fine particles such as copper oxide, which are suspended in the atmosphere.The amount of floating copper or its compounds is limited from the standpoint of human health and safety. Although the wire of the present invention does not require copper plating, it is less than that of a copper-plated wire, so it is superior to a conventional copper-plated wire in terms of human safety and health.

5. All the drawbacks of conventional copper-plated wire can be eliminated.

In addition, in terms of wire productivity, single plating equipment, plating pretreatment equipment, and waste liquid treatment equipment are no longer necessary.

2. Less factory space is needed for the unnecessary equipment mentioned above.

3. There is no risk of pollution caused by waste liquid.

9. No chemicals, water, or energy are required for plating treatment.

5 Generally, as the wire tensile strength increases, the amount of chip wear increases, but in the present invention, even if the wire tensile strength is high, the amount of chip wear is small, so the wire can be produced by omitting the intermediate sintering process in the wire manufacturing process. Now you can
There is no need for equipment or heat energy related to sintering, making it possible to significantly shorten production time.

This effect can be obtained.

[Brief explanation of the drawing]

Figure 1 is a characteristic diagram showing the bead length relationship between cracking length and coating amount per unit surface area of welding wire and cracking rate (=? In order to explain the effect, it is a characteristic diagram showing a comparison of arc start times when welding is performed under different welding conditions for a product of the present invention and a conventional product.

Claims (1)

[Claims] 1. For welding wires coated with a mixture of powdered sulfur and graphite on the wire surface, and coated with a rust-preventing lubricant containing 1.0% or more but less than 10% of organic metals, the amount of sulfur applied is determined by the unit surface area of the wire. 0.005g per 1m^2
The amount of graphite applied should be 0.01 g or more per 1 m^2 of the wire unit surface area.
A welding wire characterized by having a weight of less than 0g.