JPH0418950B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a long-life and reusable contact tip used in arc welding and a method for manufacturing the same. [Prior Art] Conventional contact tips for arc welding are mainly made of copper alloy or aluminum alloy, but since the surface of the contact tip is metal, spatter that is scattered during arc welding is susceptible to thermochemical reactions. The contact chips for arc welding may be damaged due to the fact that they accumulate on the surface of the contact tip and cause clogging, or that the contact tip is annealed and softened by the radiated heat during welding, accelerating the wear of the nozzle part due to the passing of the wire. Its lifespan was extremely short. As a method to solve the above-mentioned problems, as described in Japanese Utility Model Application Publication No. 52-26630, Japanese Utility Model Application Publication No. 59-49478, or Japanese Utility Model Application Publication No. 57-82484,
A method of protecting the nozzle part of the contact tip with a ceramic guide, or a method of covering the contact tip with ceramic as described in Japanese Utility Model Application No. 50-76021 and Japanese Utility Model Application No. 57-160887 has been proposed. There is. However, the above-mentioned method of protecting the nozzle part with a ceramic guide not only complicates the structure of the contact chip, such as screw spigots, and poses problems in terms of manufacturing costs, but also protects the entire contact chip from spatter that is scattered over a wide area. The problem was that I couldn't do it. On the other hand, the method of coating the contact chip with ceramic has the potential to solve the problem of complicating the structure and protecting the entire chip, but the coating method has not yet been established, and depending on the coating method, it may not be possible to use it. Occasionally, there were problems such as cracking or peeling of the ceramic layer. As a result of intensive research into a method of coating a contact chip with ceramic, the inventors of the present invention developed a method of coating ceramic with a PVD method or a CVD method, and previously filed an application as Utility Model Application No. 163202/1983. Although the technology disclosed in Utility Application No. 163202/1983 has greatly extended the life of arc welding contact tips,
Since the contact chip base is made of metal, especially copper alloy or aluminum alloy, the wear resistance is reduced due to annealing softening during ceramic coating treatment and annealing softening due to radiant heat during arc welding, and there is a natural limit to the service life. Ta. Furthermore, once the nozzle becomes unusable due to clogging or abrasion, there is currently no way to recycle it and it is discarded, which is another major factor that increases the cost of arc welding. . [Problems to be Solved by the Invention] The present invention provides a ceramic contact chip for arc welding that simultaneously solves the problem of clogging due to adhesion of spatter and the problem of wear resistance as described above, and can be repeatedly reproduced. The purpose of this invention is to provide a manufacturing method that can stably and reliably manufacture contact chips. [Means for Solving the Problems] In order to achieve the above-mentioned object, the present invention changes the conventional concept that arc welding contact chips are made of a good electrical conductor, and uses arc welding as shown in FIG. It was discovered that it was effective to construct the base of the contact chip with ceramics, and construct only the part that supplies power to the wire with a good electrical conductor, as shown in Figure 2.
Thermal conductivity 0.03cal/cm・sec・℃ or more, thermal expansion coefficient
Consisting of a ceramic contact chip base having physical properties of 7.3×10 ^-6 1/°C or less and a bending strength of 2500 Kg/cm ² or more, and a good electrical conductor coating layer provided on the inner wall of the wire guide hole of the contact chip, The electrically conductive coating layer is made of copper or a copper-based alloy, and the outer surface of the contact chip has a rough surface.
The above-mentioned problems are solved by having a structure with an outer surface of 20S or less. It is preferable that the electrically conductive coating layer consists of an electrically conductive layer directly coated on the inner wall of the wire guide hole of the contact chip base, and an electrically conductive layer of copper or copper-based alloy provided on the surface of the electrically conductive layer. Alternatively, the electrically conductive coating layer may be a pipe made of a copper-based alloy that fits into the wire guide hole of the contact chip base. In that case, the copper-based alloy is replaced by a Cu-Cr-Zr alloy (Cr: 1%, Cu: 99%).
It is necessary to have excellent heat resistance. Further, as a method for industrially stably manufacturing the ceramic contact chip for arc welding,
The present invention has a thermal conductivity of 0.03 cal/cm・sec・℃ or more,
Thermal expansion coefficient 7.3×10 ^-6 1/℃ or less and bending strength
It consists of a ceramic contact chip base having physical properties of 2500 kg/cm ² or more, and a good electrical conductor coating layer provided on the inner wall of the wire guide hole of the contact chip, and the good electrical conductor coating layer is made of copper or a copper-based alloy. In the method for manufacturing a ceramic contact tip for arc welding, the outer surface of the contact tip has an outer surface with a surface roughness of 20S or less, after the inner wall of the wire guide hole of the ceramic contact tip is coated in advance with an electric conductor. ,
The electrically conductive layer is used as an electrode, and an electrically conductive layer made of copper or a copper-based alloy is electroplated on the surface thereof. As for the method of electroplating the outer layer made of copper or a copper-based alloy on the inner wall of the guide hole of the ceramic contact chip mentioned above, any known method of electroplating metal on ceramic can be adopted, but the present inventors et al. According to research, it has been found that good results are reliably obtained when plating is performed using the following method. (b) TiC, which is an electrical conductor, or
A method in which the inner wall of the guide hole is coated with TiN, etc., and then electroplated with a good electrical conductor of Cu or Cu-based alloy, using the coated TiC or TiN as an electrode. (b) After coating the inner wall of the guide hole with metal powder in the form of paste or gluing,
After forming an electrically conductive layer on the inner wall of the guide hole by the so-called metallization method, which involves firing in N ₂ /H ₂ or in vacuum, Cu or
A method of electroplating Cu-based alloys with good electrical conductivity. In this metallization method, various metal powders can be used, but when the substrate is an oxide ceramic such as Al ₂ O ₃ , Ni, Mo.Cu.
Mo-Mn, if the substrate is SiC-based, Ni, Mo,
When the substrate is Si ₃ N ₄ based, particularly good results can be obtained in combination with Mo. (c) After coating the inner wall of the guide hole with an electrical conductor in advance using the electroless plating method, copper or copper is coated in the same manner as in (a).
A method of electroplating Cu-based alloys with good electrical conductivity. The electrical conductor coated by this electroless plating method may be any metal as long as it has electrical conductivity, but Ni or Cu is preferable from the viewpoint of stability and electrical conductivity. Incidentally, the coating with the electrically conductive material may extend to the threaded portion in order to improve the power feeding effect. Furthermore, as a method for industrially stably manufacturing the ceramic contact chip for arc welding, the present invention has a thermal conductivity of 0.03 cal/cm・sec・
℃ or more, a thermal expansion coefficient of 7.3×10 ^-6 1/℃ or less, and a bending strength of 2500 Kg/cm ² or more, and a good electrical conductor provided on the inner wall of the wire guide hole of the contact chip. The electrically conductive coating layer consists of a coating layer, and the electrically conductive coating layer is
In the method for manufacturing a ceramic contact tip for arc welding, the outer surface of the contact tip is made of copper or a copper-based alloy and has an outer surface with a surface roughness of 20S or less. A method for manufacturing a ceramic contact chip for arc welding has been developed, which is characterized by preparing a pipe of good electrical conductivity made of a copper-based alloy and having a diameter, and inserting the pipe into a wire guide hole in a ceramic contact chip base. It is something. In any of the above-mentioned manufacturing methods, the present invention polishes the outer surface of the ceramic contact chip substrate, that is, grinding with a grindstone such as diamond or GC, or barrel polishing with diamond or GC, etc. to improve surface roughness. Processing is performed so that the value is 20S or less, preferably about 0.5 to 2S. [Function] In the present invention, since the ceramic contact chip base for arc welding is made of ceramic, its outer surface is naturally made of ceramic. Here, it has been found that when a contact chip base is formed by firing ceramic by a known method, the surface roughness of the outer surface is 30 to 50S. Therefore, if the surface is polished to 20 or less, the adhesion of spatter during arc welding will be extremely small compared to those made of conventional metals, and the spatter grains that have adhered can be easily removed. It does not become unusable due to clogging due to adhesion. In addition, the hardness of ceramic is HV 1200.
Since the temperature is extremely high and the softening temperature is also extremely high, there is no softening due to radiated heat during arc welding, and wear on the guide hole main body due to wire passage is negligible even during long-term use. Therefore, in the arc welding contact tip of the present invention, the internal electrolytic plating or conductor rarely becomes unusable, and the electrically conductive material provided on the inner wall of the guide hole wears out as the wire passes through it, causing the wire to become unusable. It has the advantage that even if power supply becomes impossible, it can be easily regenerated by covering it again with a good electrical conductor. Any commercially available ceramic can be selected as the material for the arc welding contact tip base of the present invention, but the desired effects can be obtained.
After researching the mechanism by which cracks occur in ceramic contact chips during arc welding and conducting repeated experiments, we found that
Especially 92% as contact chip base material.
Thermal conductivity of Al ₂ O ₃ , SiC and Si ₃ N ₄ is 0.03cal/
By selecting a ceramic with physical properties of cm・sec・℃ or higher, thermal expansion coefficient of 7.3×10 ^-6 1/℃ or lower, and bending strength of 2500 kg/ ^cm It has been found that it is possible to obtain a contact tip for arc welding that has an extremely long life and does not generate any of the following. The experimental results are shown in Table 1.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings. Example 1 Ceramic materials include 92% Al ₂ O ₃ , SiC,
Three types of Si ₃ N ₄ were selected and fired by a known method to produce a contact chip substrate 1 shown in FIG. 1. The thermal conductivity, coefficient of thermal expansion, bending strength and surface hardness of these contact chip substrates were measured and the results are shown in Table 1. Further, it has been found that the surface roughness of the contact chip substrate when fired by a known method is generally 30 to 50S. Next, a non-oxide material was applied to the inner wall of the guide hole 2 of the contact chip base 1 made of three types of ceramics.
As a result of applying Ni or Cu powder as a paste to Mo powder and oxide and firing it in an N ₂ /H ₂ atmosphere, an electrically conductive layer (base material is SiK,
In the case of Si ₃ N ₄ , MoSi ₂ +Mo was formed, and in the case of 92% Al ₂ O ₃ , NiO + Ni or CuO + Cu) was formed. Next, using the electrical conductor layer as a cathode, electroplating was performed under the conditions shown in Table 2 below, and a thickness of 0.1 to 0.3 m/m was formed.
A good electrical conductor layer of Cu was provided, and then a good electrical conductor coating layer 3 shown in FIG. 2 was formed on the inner wall of the guide hole 2. Table 2 Bath composition Cuprous cyanide...120g/Sodium cyanide...135g/Caustic potash...25g/Free sodium cyanide...10g/Plating condition current density 3A/ ^dm2 PH 12.6 Bath temperature 80℃ Time 1.5hr Contact chip The outer surface of the substrate 1 was ground with a grindstone such as diamond or GC, or barrel polished with diamond or GC, etc., so that the surface roughness was 20S or less, particularly about 0.5 to 2S. The contact chips for arc welding manufactured by the above-mentioned process were prepared under Table 3 below, which is close to the actual arc welding conditions.
As a result of testing under the following conditions, no cracks occurred in any case, and the wear life of the electrically conductive coating layer 3 was as shown in Table 4 below. Table 3 Current 220A Voltage 22V Wire feed speed 600m/m/sec

[Table] ○ indicates that no cracks occur at all.
In addition, the surface roughness of the contact chip base was increased to 20S.
Hereinafter, spatter adhesion caused by the trapping phenomenon of spatter grains in surface irregularities during arc welding was suppressed by setting the temperature to about 0.5 to 2S. In addition, in this example, the electrically conductive layer is
Although the explanation has been made on the assumption that the layer is made of Cu, the same effect can be obtained even if the electrically conductive layer is made of a Cu-based alloy instead of Cu. Example 2 The inner wall of the guide hole 2 of the contact chip base 1 similar to that produced in Example 1 was coated with Ni by a known electroless plating method, and then the conditions of Example 1 were applied using this Ni electrical conductor layer as a cathode. (See Table 2), and a good electrical conductor layer of Cu was provided to form a good electrical conductor coating layer 3 (note that the structure of this example is the same as that in FIG. 2, so illustration is omitted). Also, in this example, the surface roughness of the contact chip substrate is generally 30 to 30, as in Example 1.
50S, the surface of the contact chip base is polished to a surface roughness of 20S or less, especially 0.5 by grinding with a grindstone such as diamond or GC, or barrel polishing with diamond or GC.
Processed to approximately 2S. The arc welding contact chips manufactured in the above process were subjected to a welding test under the same conditions as in Example 1 (see Table 3), and the results were as shown in Table 5 below.

[Table] ○ indicates that no cracks occur at all.
In addition, as in Example 1, by setting the surface roughness of the contact tip base to 20S or less, especially about 0.5 to 2S, it was possible to prevent the phenomenon of spatter grains being caught in the surface irregularities during arc welding. The adhesion of spatter was suppressed. In this example, as in Example 1, it is possible to obtain the same effect by forming the electrically conductive layer from a Cu-based alloy instead of Cu. Example 3 Pipe 4 made of Cu-Cr-Zr alloy (Cr: 1%, Cu: 99%) with an outer diameter of 1.90 mmφ and an inner diameter of 1.33 mmφ
A flanged pipe with a flange 5 brazed to it is forcibly inserted into the guide hole 2 (hole diameter 1.90 mmφ) of the contact chip base 1 similar to that made in Example 1 using a punch, so that it tightly contacts the inner surface of the guide hole 2. A ceramic contact chip for arc welding was manufactured using the same method. As mentioned above, the surface roughness of the contact chip base is generally 30 to 50S, so the surface of the contact chip base is ground by grinding with a grindstone such as diamond or GC, or by barrel polishing with diamond or GC. The surface roughness was polished to 20S or less, particularly about 0.5 to 2S. The ceramic contact chips for arc welding manufactured by this process were subjected to a welding test similar to that in Example 1, and the results were as shown in Table 6 below.

〔effect〕

As explained in detail above, the present invention changes the conventional concept that the base of a contact tip for arc welding should be made of a good electrical conductor such as a copper alloy, and instead makes the base of a contact tip made of ceramic. We have developed a new type of ceramic contact chip for arc welding, in which a good electrically conductive coating layer is provided as a power supply material on the inner wall of the wire guide hole, and a method for manufacturing the same, and furthermore, we have developed a ceramic contact chip for arc welding having the above structure according to the present invention. This has caused problems when using conventional arc welding contact tips.
Because it can solve the problems of spatter adhesion, wear, and recycling and reuse at the same time,
It can be said that the application effect of the present invention in the arc welding industry field is extremely large.

[Brief explanation of drawings]

Fig. 1 shows a ceramic contact tip base for arc welding of the present invention, Fig. 2 shows Embodiments 1 and 2 of the present invention, and the inner wall of the guide hole of the contact tip base in Fig. 1 is coated with a good electrical conductor. FIG. 3 shows a third embodiment of the present invention, in which a pipe made of a good electrical conductor is inserted into a guide hole of a contact chip base, and FIG. 4 shows an example of a modified embodiment of the present invention. , TiC, TiN or TiC on the outer surface of the ceramic contact chip base for arc welding
It is a figure coated with Ti (C+N). DESCRIPTION OF SYMBOLS 1... Ceramic contact chip base for arc welding, 2... Guide hole, 3... Good electrical conductor coating layer, 4... Good electrical conductor pipe, 5... Flange,
6...TiC, TiN or Ti (C+N) coating layer, 7
...Screw part.

Claims (1)

[Claims] 1. Thermal conductivity 0.03 cal/cm・sec・℃ or higher, thermal expansion coefficient 7.3×10 ^-6 1/℃ or lower, and bending strength 2500 kg/℃.
The contact chip consists of a ceramic contact chip base having physical properties of ² cm or more, and a good electrical conductor coating layer provided on the inner wall of the wire guide hole of the contact chip, and the good electrical conductor coating layer is made of copper or a copper-based alloy. A ceramic contact chip for arc welding, wherein the outer surface of the contact chip has an outer surface with a surface roughness of 20S or less. 2. The electrically conductive coating layer is characterized by comprising an electrically conductive layer directly coated on the inner wall of the wire guide hole of the contact chip base, and an electrically conductive layer of copper or copper-based alloy provided on the surface of the electrically conductive layer. A ceramic contact chip for arc welding according to claim 1. 3. The ceramic contact chip for arc welding according to claim 1, wherein the electrically conductive coating layer is a pipe made of a copper-based alloy and fitted into a wire guide hole of the contact chip base. . 4 Thermal conductivity 0.03cal/cm・sec・℃ or more, thermal expansion coefficient 7.3×10 ^-6 1/℃ or less and bending strength 2500Kg/
The contact chip consists of a ceramic contact chip base having physical properties of ² cm or more, and a good electrical conductor coating layer provided on the inner wall of the wire guide hole of the contact chip, and the good electrical conductor coating layer is made of copper or a copper-based alloy. In the method for manufacturing a ceramic contact tip for arc welding having an outer surface with a surface roughness of 20S or less, the outer surface of the contact tip is coated with an electric conductor after the inner wall of the wire guide hole of the ceramic contact tip is coated in advance with an electric conductor. 1. A method for manufacturing a ceramic contact chip for arc welding, characterized in that an electrically conductive layer is used as an electrode, and an electrically conductive layer made of copper or a copper-based alloy is electroplated on the surface of the electrically conductive layer. 5 Thermal conductivity 0.03cal/cm・sec・℃ or more, thermal expansion coefficient 7.3×10 ^-6 1/℃ or less and bending strength 2500Kg/
The contact chip consists of a ceramic contact chip base having physical properties of ² cm or more, and a good electrical conductor coating layer provided on the inner wall of the wire guide hole of the contact chip, and the good electrical conductor coating layer is made of copper or a copper-based alloy. In the method for manufacturing a ceramic contact tip for arc welding having an outer surface with a surface roughness of 20S or less, the outer surface of the contact tip is made of a copper-based alloy having an outer diameter approximately the same as the wire guide hole diameter of the ceramic contact tip base. 1. A method of manufacturing a ceramic contact chip for arc welding, which comprises preparing a pipe with good electrical conductivity and inserting the pipe into a wire guide hole of a ceramic contact chip base.