JPS585977B2 - contact tip - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a contact tip of a welding torch used in gas-encapsulated arc welding, and particularly relates to a contact tip used in consumable electrode arc welding. Arc welding, in which filler metal or welding rod and materials are melted and joined, is classified into non-consumable electrode arc welding and consumable electrode arc welding, depending on the electrode used.

In consumable electrode arc welding, the arc has strong directionality, so welding can be performed easily in any downward, vertical, or upward position, and the welding speed can be increased compared to non-consumable electrode arc welding. There is a point.

The welding torch used in the above-mentioned consumable electrode arc welding has a structure as shown in FIG. 1, for example.

That is, the contact tip 2 is provided inside the nozzle 1 with a gap serving as a gas passage.

The contact tip 2 is provided with a lead-out hole for an electrode wire 3 fed by a feeding roll (not shown).

The contact tip 2 guides the electrode wire 3 to a predetermined welding part and energizes the electrode wire 3.

The electrode wire 3 melts while generating an arc between the electrode wire 3 and the welding part due to the current flow from the contact tip 2, and welding part 1.
Weld this.

The contact tips used in this manner are required to have good electrical conductivity and thermal conductivity, as well as good wear resistance and welding resistance at high temperatures.

In other words, in order to conduct electricity to the electrode wire, it is necessary to have good conductivity, and during arc welding work, the welding torch itself becomes hot due to the arc heat generated between the electrode wire and the welding part, and in this state the electrode This is because the wire must be fed.

To explain in more detail, for example, when welding a carbon steel wire with a diameter of 1.2 mm as an electrode wire and using oxygen-containing argon gas with a DC reverse polarity (the electrode wire is the positive electrode) and a current of 20 OA, the arc generated during welding is The temperature is extremely high at approximately 6000℃, so the contact tip is also heated to 700-800℃.
In this state, the electrode wire must be fed at a high speed of 10 to 12 m/min.

On the other hand, the lead-out hole of the contact tip requires a certain degree of precision; for example, when using the above-mentioned electrode wire with a diameter of 1.2 mm, it becomes unusable if the diameter of the lead-out hole opening is about 1.8 mm.

Therefore, it is required to have good wear resistance, especially under high temperature conditions.

Conventionally, contact tips made of a chromium-copper alloy have been used to meet the above characteristics requirements.

The contact tip made of a chromium-copper alloy has particularly good conductivity, and was excellent in this respect, but the lead-out hole wore out rapidly due to the running of the electrode wire, and the corners of the opening were particularly dry. It has the disadvantage that it is easily worn out and therefore has a short lifespan.

In order to improve this point, for example, a contact tip made of a chromium-copper alloy 1 and other elements to increase its hardness, or a contact tip made of a material harder than a chromium-copper alloy is used.

However, as mentioned above, the contact tip has a diameter of 1.2
Although it is necessary to accurately machine a lead-out hole of about mm in size, such a contact tip with high hardness has extremely poor machinability and is expensive.

In order to improve these difficulties, the present invention focuses on a contact tip made of a cobalt-beryllium-copper alloy that has excellent wear resistance and a long life, and has developed a contact tip with improved machinability. It provides:

In other words, cobalt is 1 to 2 parts by weight, and beryllium is 0.1 part.
The present invention is characterized in that a copper alloy containing 0.6 to 0.6 parts and a rare earth element of 0.01 to 0.4 parts is formed using a single trowel.

: Cobalt and aluminum provide wear resistance, but if it is less than the above range, it will not have that effect, and if it is more than the above range, it will deteriorate the conductivity, so the above range is preferable.

Rare earth elements improve machinability, but o, o1%
If it is less than 0.47%, there is no effect; if it is more than 0.47%, the machinability is not improved and the conductivity is lowered, so the above range is preferable.

Next, the present invention will be described by citing typical examples thereof and comparing them with reference examples.

After melting an alloy having the composition shown in Table 1, it was hot worked to form a bar with a diameter of 10 mm.

This was solution treated at 950℃ for 1 hour and then heated to 450℃ for 5 hours.
A time aging process was performed.

A contact tip with an inner diameter of 1.0 mm was made from this material.

The machinability and lifespan of the contact tips thus obtained are shown in Table 1 along with comparative examples.

In Table 11, machining time refers to the time required to process a hole with a diameter of 1 inch and length of 45 mm, and life refers to the time it takes for the inner diameter of the contact tip to wear from 2.4 mm to 3 mm during use. be.

As is clear from Table 1, the life of the contact tip according to the present invention 1 was significantly extended compared to the conventional contact tip made of a chromium-copper alloy.

Furthermore, the machinability is improved compared to the usual Cobalttobe IJIJ Umu copper alloy.

This shows that a highly accurate contact tip can be obtained, and therefore, the contact tip of the present invention can significantly improve the workability of welding work.

[Brief explanation of the drawing]

The figure is a sectional view showing a main part of the welding torch cut away. 1... Nozzle, 2... Contact tip, 3... Electrode wire.

Claims (1)

[Claims] 1 weight part: 1 to 2 parts cobalt, 0.1 to 0.0 parts beryllium.
6% of rare earth elements, 0.01 to 0.4% of rare earth elements, and the remainder substantially of copper.