JP3153035B2 - Arc welding wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wire for gas shielded arc welding, which is excellent in wire feedability. More specifically, gas-shielded arc welding in which a so-called seamless flux-cored wire containing a solid wire and a flux agent inside the wire and having no seam portion (joint) on the wire surface and having good and stable wire feedability is obtained. It is about wires.

[0002]

2. Description of the Related Art At present, there are two types of wires for gas shielded arc welding, solid wires and flux-cored wires, of which flux-cored wires have no seam that can be manufactured by plating or wet drawing. There is a seamless flux-cored wire and a seam-filled flux-cored wire manufactured by filling a flux agent in a thin strip of steel, wrapping it, and dry-drawing. Of these wires, solid wire and seamless flux-cored wire have no seam, so copper plating can be applied to the tip attached to the tip of the welding torch, which is advantageous for electrical conductivity and wire rust resistance. It is suitable for robot welding and is being used more and more because it is difficult to give directionality to the wire, there is little wire deflection at the tip of the torch during welding, and there is little meandering of the bead.

[0003] These wires tend to be used more and more as the automation and efficiency of welding progress.
Recently, from the viewpoint of efficiency, there has been a trend toward adopting welding conditions with higher current density, regardless of automatic or semi-automatic welding, and as a result, the wire feeding speed necessarily increases. Also, depending on the target structure, welding is often performed in a narrow part. From the viewpoint of ease of use in those places, the welding torch is fed from a feed roller (wire drive wheel) of a wire feeder of a welding machine. The above-mentioned conduit cables tend to be soft and long in order to bend and make them easy to use.

[0004] As described above, when the wire feeding speed is increased and the wire is used with a long and easily bendable conduit cable, when the wire is fed, the inside of the conduit tube (generally made of steel and spring-like) in the conduit cable is used. The problem is that the frictional resistance when the wire passes through the wire increases, which hinders the wire feed at the time of welding, that the arc becomes unstable, and that the welding itself cannot be performed. For this reason,
To date, various measures have been taken to improve the wire feedability of welding wires, and many measures have been disclosed.However, there is no sufficient method yet, and welding workers often perform welding under severe conditions. They are forced to suspend, and are struggling with such measures as replacing worn conduit tubes.

[0005] To solve the problem of the feedability of these welding wires, there is a method of applying a lubricating oil to the wire surface as disclosed in Japanese Patent Publication No. 50-3256, for example.
That alone is not enough.
A method of applying wool grease, lanolin or a lanolin derivative to a wire surface as a viscosity modifier together with a neutral oil such as rapeseed oil, which is described in JP-A-57-199594, or in the description of JP-A-57-199594. Various methods such as a method of coating a wire surface with a mixture of a solid lubricant such as graphite and molybdenum disulfide in oils and fats have been proposed or implemented.

[0006]

However, these methods are still insufficient under severe conditions such as those described above, which use a soft and long conduit cable and are used under high current conditions. is the current situation. The present inventors have conducted various experiments on this problem and studied them. However, if the welding was performed for a long time under a high current condition with the soft long (6 m) conduit described above, the welding current itself would be passed. The temperature of the conduit cable can easily rise to as high as 80 ° C or more due to the resistance heat. Furthermore, the tip where the current flows from the conduit cable to the wire at the tip of the torch is connected to the electrical resistance and arc of the current when conducting. As in the conduit tube due to the radiant heat of
It was confirmed that the temperature was considerably high, and it was found that these materials further increased the wire feeding resistance and deteriorated the wire feeding property.

[0007]

Means for Solving the Problems The inventors of the present invention have studied the lubricant to be attached to the wire in addition to these viewpoints, and have found that a lubricant containing an appropriate amount of an organic molybdenum compound is added to a base lubricant. Have found that the wire feedability is very good under the harsh conduit cable and welding conditions. That is,
The gist of the present invention is that lubricating oil is used as a base oil.
An arc welding wire characterized in that 0.2 to 2 g of a lubricant containing up to 30% of an organic molybdenum compound is adhered per 10 kg of wire.

[0008]

The wire of the present invention is characterized in that a suitable amount of a lubricant containing an appropriate amount of an organic molybdenum compound is adhered to a lubricating oil as a base oil. Animal and vegetable oils, mineral oils and synthetic oils are used as base oils. These lubricants can be used alone or as a mixture. These lubricating oils basically have the role of lowering the frictional resistance in the wire conduit and lowering the feed resistance. In addition to the base oil, graphite, molybdenum disulfide, or a CF-based solid lubricant having a role of further reducing frictional resistance at a high temperature can be used in combination as needed. Examples of the organic molybdenum compound include molybdenum dithiophosphate, oxymolybdenum sulfide organo, phosphorodithioate, and the like.
It is considered that the frictional resistance of the wire in the tip and the conduit tube at a higher temperature and a higher load is reduced, and the feed resistance is reduced.

Conventionally, vegetable oils generally used as wire lubricating oils have low viscosity, and have a temperature of 40.degree.
When the temperature rises to ℃, its viscosity becomes extremely low.
When the conduit cable becomes hot and under severe conditions where the conduit is used with a small radius of curvature, the lubricating effect becomes very small. When a solid lubricant such as molybdenum disulfide is added, the heat resistance increases and its effectiveness is confirmed. However, when this solid lubricant is used by suspending it in a lubricating oil, the difference in specific gravity is large and separation is easy, so that its uniform coating property on a wire is a problem. Also in this regard, the organic molybdenum compound has a small specific gravity, has good dispersibility in base oil, and has a solubility depending on the base oil, and can be used as a solution instead of a suspension. Uniform adhesion becomes possible, and the wire feedability is remarkably improved.

It is necessary to add the organic molybdenum compound in the base oil in an amount of 5% or more. Below this, no clear efficiency has appeared in the feeding test.
However, the addition of 30% or more is a powdery substance having a small apparent specific gravity of the organic molybdenum compound, and the addition of the compound increases the viscosity of the lubricating oil, making it difficult to uniformly attach the compound to the wire surface, which is not preferable. Incidentally, as a method of attaching this lubricant to the wire surface, usually,
The most preferable method is to use it as a lubricating oil for the final die in the wire drawing process in terms of uniform adhesion.However, in some cases, such as roll coating or felt coating before loading into a spool winding or a pail pack, etc. A method is also possible. The amount of these solid lubricants added to the base oil when used in combination with graphite or molybdenum disulfide also increases the viscosity of the base oil and hinders the adhesion to the wire surface. The total amount is limited to 35%.

Next, the amount of the lubricant attached to the wire of the present invention must be 0.2 g or more and 2 g or less per 10 kg of the wire. If it is less than 0.2 g, the lubricating effect is not clearly seen in the feeding evaluation test. When the amount of adhesion exceeds 2 g, good feedability can be obtained, but harmful effects such as blowholes and hydrogen cracking are caused by the increase in the hydrogen content in the deposited metal mainly due to the H ₂ source contained in the lubricating oil. Defects are likely to occur, which is not preferable.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described based on embodiments. Table 1 shows a combination example and an adhesion amount example of the lubricant applied to the welding wire of the present invention, and the results of the comprehensive evaluation of the feedability together with the comparative examples.
In Table 1, No. Nos. 5 to 10 are examples of the present invention in which organic molybdenum is appropriately blended. Nos. 1 to 4 and Nos. 11-
14 is a comparative example. As a method of coating on the surface of the wire, a combination of coating with a final die at the time of manufacturing and felt coating was used. The welding wire used at this time was a copper-plated steel wire with a wire diameter of 1.2 mm (solid wire,
JIS Z3312, YGW11 type, component, C0.
07%, Si 0.80%, Mn 1.60%, Ti 0.2
0%), except for the final die lubricant and the lubricant for felt coating during spool winding. The table also shows the amount of lubricant attached and whether or not there is a problem in production.

In the wire feedability test, welding was performed under the same conditions using the same welding machine, and the welding time was 10 minutes (however, after 5 minutes of continuous welding, the welding was stopped for 10 seconds, and 5 minutes of continuous welding for a total of 10 minutes).
Observe whether or not the wire has been fed at a fixed rate without stopping the feeding in the middle, and for those that were able to be welded to the end for 10 minutes, depending on the load of the armature current value of the feed motor at the time of wire feeding The evaluation was based on the range of fluctuation and the magnitude. The larger the current value, the worse the feeding property, and the smaller the current value, the better.

As shown in FIG. 1, the test apparatus has a welding machine 1 equipped with a welding wire spool 2 and a wire feeding roller 3.
Then, the wire 4 is fed to the welding torch 6 via the conduit cable 5 and is sent out together with the shielding gas from the nozzle 7 to generate an arc. The test was performed by rotating at a speed of. A conduit tube having a length of 6 m was used, and one turn of 200 mmφ and a bend of 250 mmR near the torch were provided on the way. The welding conditions are as follows.

Welding current (A) 300 電 圧 Voltage (V) 30 速度 Speed (m / min) 30 Shielding gas condition CO ₂ , 20 l / m
in Wire overhang length (mm) 25

As is evident from Table 1, the automatic or semi-automatic wire coated with the lubricant containing the organic molybdenum compound of the present invention can obtain a sufficiently satisfactory feedability and a good arc state weld bead. Also, the welding results were good. Comparative Example No. 1 to No. No. 4 shows an example according to the prior art. 1 to No. When only the base oil No. 2 was used, welding could not be performed for 10 minutes, and the welding was interrupted due to poor feeding halfway. No. 3 and No. 3 No. 4 is No. 1 to No. 2, the effect of adding a solid lubricant was observed, and welding was completed to the end. However, in some cases, the arc became unstable, the motor armature current was higher than that of the present invention, and the feedability was poor. Was enough.

Comparative Example No. Nos. 11 to 14 use an organic molybdenum compound as a lubricant. In No. 11, the amount of lubricant adhered was small, the feedability was poor, and welding was interrupted on the way. N
o. On the other hand, No. 12 had a large amount of adhesion, and a pit (hole) -like defect was occasionally observed on the weld bead due to the H ₂ source. N
o. 13 and No. 14 is determined that the addition amount of the solid lubricant in the base oil is large, the flowability of the lubricant put in the die box is poor at the time of wire production, and it is not possible to constantly attach the lubricant uniformly to the wire, Production has been suspended.

[0018]

[Table 1]

[0019]

As described above, the lubricant of the present invention is
By using it as a wire drawing lubricant or as a coating lubricant after wire drawing, it becomes possible to obtain a wire for arc welding with good feedability and arc stability, and use a soft and long conduit cable In addition, even under severe use conditions such as those used under high current conditions, welding work can be performed comfortably without welding interruption due to poor wire feeding.

[Brief description of the drawings]

FIG. 1 shows a test apparatus for examining wire feedability used in an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Welding machine 2 Spool 3 Feeding roller 4 Wire 5 Conduit cable 6 Welding torch 7 Nozzle 8 Steel material 9 Turntable

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B23K 35/36 B21C 9/00-9/02

Claims (1)

(57) [Claims] 1. A lubricating oil is used as a base oil on a wire surface.
An arc welding wire, wherein 0.2 to 2.0 g of a rust preventive lubricant containing up to 30% of an organic molybdenum compound is adhered per 10 kg of the wire.