JPS5927674B2 - Contact tip for consumable electrode type arc welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a consumable electrode arc welding method (MIG welding, CO2
The present invention relates to a consumable electrode type arc welding contact tip used for welding.

For consumable electrode arc welding, contact tips (
The chip (hereinafter referred to as the tip) serves as a guide for supplying the consumable electrode (hereinafter referred to as the wire) to the welding area through a wire passage provided in its center, and also serves as a feeder for supplying welding current to the wire.

However, since the wire is fed at a high speed and the power feeding point portion on the inner surface of the chip becomes hot, the portion of the wire through hole that comes into contact with the wire is significantly worn. As a result, conventional tips are unable to play the role of guiding the welding wire due to wear of the wire passage hole, and depending on the wear condition, the power supply condition deteriorates, resulting in defective welding, and arc This makes the structure unstable and causes defects such as blowholes. Therefore, in the automatic welding process, we try to prevent welding defects by replacing the tips with new ones early and regularly, but this reduces productivity due to process stoppages for replacement, and the necessary The cost of artificial or new chips is considerable. The present invention provides a tip that eliminates the above-mentioned drawbacks.The tip part on the wire contact surface is made of a beryllium copper alloy that has excellent wear resistance at high temperatures, so that it has a long service life and does not cause welding defects. The company succeeded in providing a chip that is difficult to use.

That is, as shown in FIG. 1, the present invention provides a contact tip 1 for consumable electrode type arc welding, in which the portion of the contact tip (here, the exit side tip 2) in contact with the consumable electrode is made of 1.7% or more beryllium. This is a contact tip for consumable electrode type arc welding, characterized in that it is made of beryllium copper alloy containing 4.2% and subjected to precipitation hardening treatment, and the remaining part 3 is made of chromium copper alloy. The chromium steel alloy that is the main constituent material of the chip of the present invention is one that has been commonly used in commercially available chips.

In addition, the beryllium copper alloy used as the constituent material of the contact area between the wire and the chip has a hardness of H after age hardening treatment.
It is desirable to have a v value of 300 or more, and therefore the beryllium-copper alloy must have a beryllium content, which is the main chemical component, in the range of 1.7% to 4.2%.

If the amount of beryllium is less than 1.7 (Fb), the hardness after age hardening will not reach Hv3OO, and if the amount of beryllium exceeds 4.2%, intermetallic compounds will occur in the structure and it will become brittle, which is metallurgically disadvantageous. This is not preferable because it results in a metal structure of
A beryllium copper alloy equivalent to 172O can be used. In the chip of the present invention, all the parts where the wire and the chip come into contact, for example, all the parts forming the through holes, can be made of beryllium-copper alloy. However, beryllium copper alloy has lower conductivity and higher material cost than chromium copper alloy, which is the conventional chip material, so it is not necessarily a good idea to make all of the contact surfaces between the wire and the chip from beryllium copper alloy. isn't it. As shown in FIG. 1, it is sufficient to construct only the outlet end portion 2 of the wire passage hole 4 from beryllium-copper alloy.

More precisely, the length of the through hole in the tip 2 in the axial direction must be at least twice the diameter of the welding wire used. If it is less than this, the wear of the tip portion 2 by the wire will be large and the durability will not be sufficiently improved. In addition, the tip part 2
Even if the axial length of the wire exceeds 5 times the wire diameter, the durability will not exceed 3. Also, the tip 2
The diameter of the through hole is most preferably 1.08 to 1.20 times the wire diameter. If the diameter of the through hole is smaller than 1.08 times the diameter of the wire, it may be difficult for the wire to pass through, and the wire may not be able to be fed during use. 5. If the wire diameter exceeds 1.20 times, heat generation will be severe during use and the durability of the chip will be impaired.

The tip end portion 2 of the chip may be made of beryllium-copper alloy by any of the commonly used bonding methods, ie, mechanical bonding, chemical bonding, and metal bonding. However, from the viewpoint of not damaging the electrical conductivity and thermal conductivity of the chip itself during welding, it is desirable that the chromium copper alloy and the beryllium copper alloy be bonded metallically, and it is also preferable that the bonding process requires less effort. is preferred. From this point of view, in practice, a method is used in which a beryllium copper alloy is built up on the tip of a chromium-copper chip by MIG welding. The chips of the present invention are 4 to 10 times more durable than conventional chips.

Examples will be explained below. Example 1 A mortar-shaped gouge (opening diameter: 571 tm, depth: 5 m) was cut into the tip of a commercially available chromium-copper alloy chip.
The diameter of the m1 bottom is 1.6mm), and the gouge is 1.8mm.
Welded a beryllium copper alloy containing %Be by MIG welding, and then drilled the built-up part to 1.6m77! φ
The wire hole was passed through the wire.

After that, the wire through hole and the tip of the built-up part are machined, and then hardening heat treatment (315°C, 2 hours) is performed in a vacuum.
A chip for the product of the present invention was completed. Using this chip welding voltage 25V1 welding current 220A1 welding speed 5001N
CO2 arc welding was performed under the following conditions: /Min distance between base metals: 20m, 7n1, outer diameter of welding wire: 1.2mm.

The amount of wear expansion of the wire through hole for a welding length of 20 m is 0.
The abrasion resistance was only 0.05 mm1, which is 4 times higher than that of the conventional chromium-copper alloy chip containing 0.80 I)Cr (wire hole diameter 1.6 m1Lφ), which had a wear expansion of 0.20 nm1 under the same conditions.

Incidentally, the amount of wear enlargement of the wire through hole for other weld lengths is shown in FIG. 2b. Further, for reference, the amount of abrasion expansion of the wire through hole with respect to the weld length in the case of a conventional chromium-copper alloy chip is also shown in FIG. 2a. Example 2 The wire through hole diameter was 1.3 mmφ by the same method as Example 1.
The chip of the present invention was completed.

Using this chip, C
O2 arc welding was performed. The amount of wear expansion of the wire hole for a welding length of 20 m is only 0.027!1 m1, compared to the amount of wear expansion of a conventional chrome-copper alloy chip (wire hole diameter 1.6 mm) under the same conditions of 0.20 mm1. 10
It showed double the wear resistance.

Note that the amount of wear expansion of the wire through hole for other weld lengths is shown in c in FIG.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of the contact tip of the present invention, and FIG. 2 shows the amount of abrasion expansion of the wire through hole with respect to the welding length. In Fig. 2, a represents the wire through hole wear enlargement of the conventional chromium-copper alloy chip with a wire through hole diameter of 1.6 m (71 Lφ), and b and c represent the wire through hole diameter of the present invention chip with a wire through hole diameter of 1.6 R, respectively.
The amount of wire through hole wear expansion when using a wire with a diameter of 1.31 nm is shown. 1...Contact tip, 2...Exit side tip, 3...Remaining part,
4... Wire through hole, 5... Wire.

Claims (1)

[Claims] 1. In a contact chip having a consumable electrode through hole in the center, the part of the contact chip in contact with the consumable electrode is made of beryllium containing 1.7% to 4.2% beryllium and subjected to precipitation hardening treatment. A contact tip for consumable electrode type arc welding characterized by being made of a copper alloy and the rest being made of a chromium-copper alloy. 2. A patent characterized in that a contact tip portion made of beryllium copper alloy is located at the tip end on the exit side of a consumable electrode through hole, and its length in the axial direction of the through hole is at least twice the diameter of the consumable electrode used. A contact tip for consumable electrode type arc welding according to claim 1. 3. The consumable electrode type according to claim 2, wherein the consumable electrode hole diameter of the portion made of beryllium copper alloy is 1.08 to 1.20 times the diameter of the consumable electrode used. Contact tip for arc welding.