JPS61296969A - Ceramic coating contact tip for arc welding - Google Patents

Abstract

PURPOSE:To prolong the life of a contact tip by forming the intermediate coating layer consisting of group 4a metal, etc. on the surface of the basic body of the contact tip, further by forming a ceramics coating layer on the outer surface thereof. CONSTITUTION:The basic body 1 of the copper alloy made contact tip providing the prescribed shape is produced. The intermediate coating layer of the group 4a metal of Ti, Zr, Hf, etc. or at least more than one kind of the alloy thereof is formed in less than 3mum thickness on the surface of a tip 1 and the tip part of a wire feeding hob 2. The ceramics coating layer 3 of TiN, etc. is then formed on the surface of the coating layer 4 of the contact tip thereof via an adequate ceramics coating equipment. The adhesive strength among the intermediate coating layer 4, ceramics layer 3 and basic body 1 is extremely high and yet the separation of the coating layer 3 is eliminated and the adhesion of spatters is checked as well. The life of the contact tip is therefore prolonged.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a contact tip for supplying power to a welding wire in arc welding, and more particularly, it has characteristics of wear resistance, spatter resistance, and reaction resistance. The present invention relates to a contact tip for friendly arc welding in which a ceramic coating layer is formed on the surface of the base to improve heat.

[Prior art]

Arc welding is currently widely used to join metals, and gas shield arc welding, in which welding is performed while supplying inert gas or carbon dioxide to the molten metal part, is particularly widespread.

The tip of the welding torch used for arc welding as described above is provided with a contact tip for supplying power to the welding wire. Usually made of copper alloy.

However, since normal contact tips are made of copper alloy as mentioned above, the surface of the contact tip causes a thermochemical reaction with the spatter that is scattered during welding, and the spatter is transferred to the surface of the contact tip and the wire feed hole. Copper alloys are relatively soft and can be annealed and softened by welding heat, causing severe wear when the wire passes through them, and these problems can shorten the life of the contact tip. I used it as a hobby.

As a method to solve the above-mentioned problems, especially the problem of adhesion of sputter to contact chips,
Publication No. 59-4947 or Utility Model Application No. 59-4947
As described in Japanese Patent No. 7-82484, a method has been adopted in which the contact tip is imprinted with a ceramic guide, but this method not only complicates the structure of the contact tip and causes problems in terms of cost. However, there was a problem in that the entire contact chip could not be protected from widely scattered spatter.

As an alternative to the conventional method, the present inventors developed a technique for coating the surface of a contact chip using a CVD method or a PVD method, and previously filed an application as Utility Model Application No. 163202/1983. The invention related to this application succeeded in solving the problems of spatter adhesion and wear using relatively simple means, and greatly extending the life of the contact tip.
In this technology as well, since the ceramic coating layer is formed directly on the contact chip substrate by CVD or PVD, the adhesive strength between the ceramic coating layer and the substrate is not very strong, and if used for a long time. 1. The ceramic coating layer may peel off, etc. There were still problems to be solved.

[Problem that the invention seeks to solve]

The present invention solves the shallow problems in the technology described in Utility Model Application No. 163202/1982, namely, the problem of adhesive strength between the contact chip and the ceramic coating layer, solves the problems of sputter adhesion and abrasion, and The overall purpose of the present invention is to provide a contact tip for arc welding that can withstand long-term use and also solves the problem of peeling off.

[Specific measures to solve all problems]

As a result of intensive research into specific means for achieving the above object, the present inventors have discovered that an intermediate layer between the contact tip and the ceramic coating layer is made of at least one metal or alloy selected from the Group 43 metal group. The present invention was completed based on the finding that the above object can be achieved by providing a coating layer.

That is, the contact tip for arc welding according to the present invention includes a copper alloy contact tip base body having a welding wire feeding hole for feeding power to a welding wire, and a copper alloy contact tip base body made of a copper alloy made of a group 4a metal formed on the surface of the contact tip base body. Preferably consisting of at least one metal or alloy selected from the group 3
A ceramic-coated arc welding contact tip comprising an intermediate coating layer having a thickness of μ or less and a ceramic coating layer formed on the outer surface of the intermediate coating layer, and preferably,
The intermediate coating layer and the ceramic coating layer are ceramic-coated arc welding contact tips in which the intermediate coating layer and the ceramic coating layer extend to the tip of the inner wall of the welding wire feeding hole.

[Effect]

The contact tip for arc welding of the present invention has a rounded surface with a highly hard ceramic coating layer that does not easily cause a thermochemical reaction with spatter. etc., and there is almost no need to consider the wear associated with it.

Further, in the present invention, an intermediate coating layer made of at least one metal or alloy selected from the Group 43 metal group having a strong bonding force between the copper alloy contact tip base body and the ceramic coating layer. As a result, the adhesive strength between the ceramic coating layer and the substrate is high, and the ceramic coating layer will not peel off even during long-term use.

It has been confirmed that the above effect is particularly great when the thickness of the intermediate layer is 3 μm or less.

Furthermore, as an embodiment of the present invention, the intermediate coating layer and the ceramic coating layer are extended to the inner wall tip 5 of the welding wire feeding hole of the contact tip as shown in FIG.
Wear of the hole due to passage of the welding wire is also effectively suppressed.

The types of ceramics used in the present invention include:
Although the desired effect can be obtained using any commercially available ceramic, according to the experiments of the present inventors, T
iN, Tic, Ti (C+N).

ZrN, HfC, HfN, Hf (C,N),
Si, N, OLbiht, 0. It has been confirmed that the effect is particularly large when selected.

〔Example〕

Example 1 As shown in Figure 1, a copper alloy (Cu-11Cr
) A contact tip base l is cultivated, and two
(2) Metallic Ti4 was applied to a thickness of 0.2 μm in the following range.

Next, the metal Ti-coated contact tip was attached to the work holder 6 of the PVD ceramic coating apparatus shown in FIG. of Ti
A N coating layer 3 is formed, a copper alloy (Cu-1%Cr) contact chip substrate 1, a Ti intermediate coating layer 4, and a TiN
A contact tip for arc welding (hereinafter simply referred to as the product of the present invention) comprising the coating layer 3 was obtained.

Next, a contact chip of the present invention, a comparison contact chip (hereinafter simply referred to as a comparison product) coated directly on the substrate surface with a Ti intermediate coating layer 4 ≧1N3ft without any intervening Ti intermediate coating layer 4, and a conventional contact chip without ceramic coating ( An arc welding life test was conducted on three products (hereinafter simply referred to as conventional products). The results of this life test are shown in FIG. The conditions for this life test are 150A, 200A, 25O
This is the result of repeating each welding current of A for 10 minutes and stopping the power supply for 5 minutes, and the protruding length of the welding wire is 15 lines.

Furthermore, the life span in this embodiment refers to the time when the welding current begins to rapidly decrease due to spatter adhesion or wear.

As is clear from Figure K5, it can be seen that the product of the present invention has a lifespan of more than 4 times longer than conventional products for any of the current novels, and more than twice as long as the comparative product.

Also, when observing the surface of the contact tip during its lifetime,
Spatter is deposited on the surface of the conventional product and the tip of the wire passage hole, and spatter is observed on the surface of the comparative product where the TiN layer is peeled off or in cracks, whereas spatter is deposited on the surface of the product of the present invention. The amount of spatter was extremely small, 1/2 to 1/3 compared to comparative products.

Example 2 Example 1 shows a product of the present invention using the same copper alloy substrate as in Example 1, but with different types of intermediate coating layer and ceramic coating layer as shown in the table below, and a corresponding comparative product. These products are manufactured using the same process as the welding current 22.
The following table shows the results of measuring the number of times welding can be repeated with power supplied for 10 minutes and stopped for 5 minutes under welding conditions of 0A, voltage 24v, and torch speed 600 mornings/sec. As is clear from this table, in this test as well, the products of the present invention were significantly superior to comparative products, and had a lifespan more than four times longer than conventional products.

In this example, the PVD method is used as a means of forming the ceramic coating layer, but it has been confirmed that similar results can be obtained with the CVD method, and the hole intermediate coating layer can also be formed by ion blating, It is the same whether it is formed by any means such as vapor deposition.

〔effect〕

The ceramic-coated contact tip for arc welding of the present invention has an intermediate coating between the copper contact tip and the ceramic coating layer, which is made of at least 1s metal or alloy selected from the Group 4a metal group, which has a strong bonding force to both. The reason why the layer is interposed is that the adhesive strength between the base and the ceramic layer is extremely high, and the ceramic coating layer does not peel off even after long-term use. The effect of the ceramic coating that suppresses internal and external wear can be maintained for a long time.

Considering that clogging due to adhesion of spatter and wear due to wire passage are major factors that affect the lifespan of contacts and, in turn, the productivity of arc welding, it is possible to solve this problem at the same time. It can be said that the effects of the present invention, which have solved the problem, are extremely large.

[Brief explanation of drawings]

Fig. 1 shows the shape of the contact tip substrate, Fig. 2 shows an example of applying a ceramic coating directly to the contact tip substrate, Fig. 3 shows the ceramic coated contact tip of the present invention, and Fig. 4 uses the flPVD method. The ceramic coating device and FIG. 5 are diagrams showing the results of a life test of the contact tip. DESCRIPTION OF SYMBOLS 1... Contact chip base body, 2... Wire feeding hole, 3... Ceramic GT layer, 4... Intermediate treated layer, 5... Wire feeding hole tip, 6... Work holder, 7...Rotating drum.

Claims (3)

[Claims] (1) A copper alloy contact tip base having a welding wire feed hole for supplying power to the welding wire, and at least one metal selected from the Group 4a metal group formed on the surface of the contact tip base. Or a ceramic-coated contact tip for arc welding, comprising an intermediate coating layer made of an alloy, and a ceramic coating layer formed on the outer surface of the intermediate coating layer. (2) The ceramic-coated contact tip for arc welding according to claim 1, wherein the intermediate coating layer has a thickness of 3 μm or less. (3) The ceramic coating according to claim 1 or 2, wherein the intermediate coating layer and the ceramic coating layer extend to the tip of the inner wall of the wire feeding hole of the contact chip base. Contact tip for arc welding.