JPH01259158A - Method for improving durability of electrode tip - Google Patents

Abstract

PURPOSE:To improve the durability of an electrode tip by embedding a ceramic pipe in the head of a metallic electrode tip for welding, and forming a thin film of a metal or the nitride and carbide of a metal having high heat resistance and less wettability with molten metal on the surface of the pipe. CONSTITUTION:A pipe made of a ceramic such as steatite, forsterite, wollastonite, mullite, zircon, cordierite, alumina, zirconia, silicon carbide, and silicon nitride and cermet and having 1-5mm length and about 0.5mm thickness is embedded in the filler metal wire supply hole at the head of an electrode tip to be used in the welding and cutting of a metal. The surface of the electrode is then cleaned by an org. solvent such as trichlene, further plasma-cleaned with an inert gas such as Ar, and activated. The surface is then coated with B, Al, Si, Ti, V, Cr, Zr, Hf, Ta, W, or their alloy, nitride, or carbide in 1-10mum thickness by sputtering, ion plating, CVD, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> This method relates to prevention of wear and deterioration of electrode tips during welding and cutting of metals.

<Prior Art> Conventionally, various methods have been adopted for welding in response to demands for high quality and automation. In metal arc welding using the most common coated arc welding rod, a coated wire is applied to the metal core wire to be fusion welded to stabilize the arc. The improvement and development of coated arc welding rods has made it possible to weld special steels and special metals, which had previously been considered extremely difficult. Furthermore, recently, inert gas welding methods and carbon dioxide welding methods have been developed that use gases such as inert gases and carbon dioxide gas to weld by enclosing the arc but blocking air, making it possible to perform high-speed and highly efficient welding. Became.

<Problems to be solved by the invention> However, as speeds and efficiency increase, more powerful arcs are used, leading to wear and tear due to melting or abrasion of welding nozzles and electrode tips, and spattered metal particles. The problem of continuous high-quality welding being impossible due to the turbulence of the gas flow due to adhesion and the impairing the uniform supply of filler metal from the chip has remained unresolved.

In order to solve the above problems, the present inventors embedded a thin ceramic pipe with high wear resistance at the tip of the electrode tip and used a welding wire as a filler metal. As a result of intensive research, we came up with the idea of preventing tip wear and using a dry coating method to form a thin film on the surface of the welding electrode tip that is highly heat resistant and difficult to wet with molten metal, and is composed of metals and metal nitrides and carbides. The present invention has been completed by discovering that the above problems can be solved when a thin film is formed by sputtering, ion plating, or plasma CVD. That is, the method of the present invention embeds a ceramic pipe at the tip of a metal conductor chip and fills the surface with hafnium, tantalum, tungsten, boron nitride, aluminum nitride, silicon nitride, titanium nitride, vanadium nitride, chromium nitride, zirconium nitride. , hafnium nitride, tantalum nitride, tungsten nitride and aluminum carbide, silicon carbide, titanium carbide, vanadium carbide, chromium carbide, zirconium carbide 1, hafnium carbide, tantalum carbide, tungsten carbide, and nitrides having an alloy composition of the above metal elements, or By dry coating the carbide to a thickness of 0.1 to 10 μm, a heat-resistant, abrasion-resistant coating with a large sputter adhesion prevention effect is formed, thereby improving the durability of the electrode chip.

The above invention will be explained in more detail. - A pipe made of ceramic is embedded in the filler wire supply hole at the tip of the electrode tip, which is generally made of a chromium-copper alloy. The inner diameter of the hole in the ceramic pipe is 100 to 115% of the diameter of the filler wire used. 10
If it is less than 0%, the wire will not be supplied without resistance, and 11
If it exceeds 5%, it becomes impossible to accurately supply the filler metal wire to the position to be welded. The thickness of the ceramic should be at least 0.5 mm, and the length should also be 1.
．． 0 to 5.0 mm is sufficient. If the wall thickness is less than 0.5mm, there will be problems with durability and there will be defects that increase costs in ceramic pipe manufacturing. In terms of length, if i is less than 0 mm, the strength is insufficient, and if it is more than 5.0 mm, the electrical conductivity between the filler metal wire and the electrode tip is inhibited. In order to coat this ceramic vibe embedded electrode chip, the surface is cleaned. Generally, oil and fat are removed using an organic solvent such as trichlene, triflon, or triethane, and then arbogas etc. are removed in a vacuum container. Perform plasma cleaning with inert gas to activate the surface,
Apply to the coating. The coating may be performed by sputtering, ion plating, or plasma CVD, and a coating with high adhesion can be obtained. Regarding the film thickness of the coating film, if it is less than 0.1 μm, sufficient effects such as heat resistance and spatter prevention cannot be obtained, and if it is 10 μm or more, the film quality will deteriorate due to the accumulation of internal stress in the film, and it will take time to deposit the film. The sputtering conditions that cause problems in productivity are usually a vacuum level of 1 x 10 to 3 x IO torr, an argon pressure of 1 x 10 to 1 x 1 torr, and a voltage of 35 torr.
0 to 550 cm, and a discharge current of 10 to 100 A. If the degree of vacuum is less than 1X10 torr, it takes time to reach the degree of vacuum, which causes problems in productivity, and if it exceeds axio torr, the color tone of the sputtered film becomes dark and the film composition contains oxygen, which is undesirable. If the argon pressure is less than 1X10 torr, it will be difficult to maintain the discharge, and IXIQ-" torr
If it exceeds r, it will be difficult to obtain a good quality sputtered film. The voltage is 35
If it is less than 0■, the discharge becomes unstable, and if it exceeds 550■, the current efficiency decreases, causing problems in productivity.

If the discharge current is less than IOA, the discharge will become unstable and 100%
If it exceeds A, the thickness of the sputtered film tends to vary.

・' Also, during sputtering, high frequency (13, 56 MHz) current can be used depending on the type of target used. In addition, in order to deposit nitrides and carbides in reactive spacing and taring, the reactive gas is made to have a partial pressure of 101 to 1:1 with respect to the spack pressure, and is subjected to spantasong. - In the case of nitriding on a boat, nitrogen sludge and ammonia sludge were used as the reaction gas, and in the case of carbonization, acetylene sludge was used.

The conditions for ion plating are as follows: an electron beam is used as the evaporation source, and the gas pressure (nitride, carbonization: Hyas 30
The voltage was 0V to 1500V.

The conditions for plasma CVD are: vacuum level 1 x 10 torr, gas pressure 5 x IQ torr RfIKw (13,
56M), treatment temperature 400'C1 The residue used was moiety of titanium tetrachloride, silicon tetrahydride, aluminum, and ammonia.

<Example ■> The tip hole of a commercially available carbon dioxide arc welding electrode tip was made of alumina and had an inner diameter of 1.25 mm and an outer diameter of 2.25 mm.
A coating of high melting point metals such as hafnium, tantalum and tungsten is applied by DC magnetron sputtering using an electrode tip fitted with a 3 mm long pipe.

The film thickness was 5 μm and was formed under the following sputtering conditions S. Vacuum degree 1X10 torr, sputtering argon pressure 5X10 torr, discharge voltage D
A welding test was conducted at C450V and a discharge current of 2OA using this metal-coated torch and a commercially available torch. Welding was performed using an automatic welding machine at a welding current of 25 OA and a welding speed of 2.5 meters per minute.Coating wire weight evaluated based on the weight of welding wire (1.2 mm DS-1) that could be welded before replacing the electrode tip. Blank (commercial product) 6Kg Tungsten coated product 56Kg Tantalum coated product 58Kg Hafnium coated product 65Kg As is clear from these results, it can be seen that the improved product according to the present invention has a significantly longer life than the conventional product.

<Example ■> The tip hole of a commercially available carbon dioxide gas arc welding electrode tip was made of alumina and had an inner diameter of 125 mm and an outer diameter of 2.25 mm.
Reactive sputtering using an electrode tip fitted with a 3 mm long pipe (the partial pressure of the reactive gas was 3 x 10 torr using nitrogen or acetylene).
The following nitride/carbide was coated with a thickness of 2 μm and subjected to a welding test. The welding test was performed using an automatic welding machine at 250A, 2.5m/min, 1.2mmDS-1.
We compared the weight of wire that could be processed before replacing the tip using the .

Covering Wire weight blank (commercially available) 6Kg Boron nitride 53Kg Aluminum nitride 48Kg Titanium nitride 25Kg Vanadium nitride 27Kg Chromium nitride 22Kg Zirconium nitride 30Kg Hafnium nitride 42Kg Tantalum nitride 38Kg Tungsten nitride 34Kg Boron carbide 58Kg Carbon Aluminum oxide 42Kg Silicon carbide 58Kg Titanium carbide 45Kg Carbonization Vanadium 39Kg Chromium carbide 34Kg Zirconium carbide 42Kg Hafnium carbide 53Kg Tantalum carbide 58Kg Tungsten carbide 47Kg Nitride/Ti, AI, V 38Kg Nitride/Ti, AI 41Kg The coated product according to the present invention has a remarkable effect over conventional uncoated products. Shows excellent results.

<Example ■> The tip hole of a commercially available carbon dioxide gas arc welding electrode tip was made of alumina and had an inner diameter of 125 mm and an outer diameter of 2.25 mm.
An electrode tip fitted with a 3M long pipe was coated with the following coating by high frequency plasma CVD and subjected to a welding test. The CVD conditions were as follows: using hydrogen as a carrier gas, bubbling silicon tetrahydride or titanium tetrachloride, and acetylene or ammonia at a ratio of 1:1, CVD gas pressure 5xlQ torr, Rf:
It was coated to a film thickness of 3 μm at IKw and treatment temperature of 400'C. Welding test conditions were automatic welding at 250A and welding speed at 2.
．． 5m/min, 1.2mm DS-1 wire was used, and the weight of the wire that could be welded before the tip was replaced was compared.

Covering Wire weight Commercial product (blank) 6Kg Silicon nitride 22Kg Titanium nitride 19Kg Silicon carbide 3.8 Kg Titanium carbide
30Kg The product of the present invention shows superior effects compared to comparative products.

<Example ■> The tip hole of a commercially available carbon dioxide arc welding electrode tip was made of alumina with an inner diameter of 125 mm and an outer diameter of 2.25 mm.
An electrode tip fitted with a pipe having a length of 3IIIff+ was coated with titanium nitride and titanium carbide by an ion plating method, and a welding test was conducted. The ion plating conditions were ion beam method, gas pressure (nitrogen or acetylene) IXIO'torr, bias voltage 800V, and coating to a thickness of 3 μm. Welding test conditions were automatic welding, 25OA, welding speed 2.5m/min, 1.
A 2mm DS-1' wire was used and the weight of the wire used until Chinov replacement was compared.

Coating Wire weight Commercial product (blank) 6Kg Titanium nitride 30Kg Titanium carbide 50Kg According to the present invention. It can be seen that the coated product is clearly superior to the untreated commercial product.

Claims (1)

[Claims] In a method for improving the durability of an electrode tip in arc welding, gas welding, and plasma welding, (a) steatite, forsterite, wollastonite, mullite, Embed a pipe made of ceramics such as zircon, sponge membrane, cordierite, alumina, zirconia, silicon carbide, silicon nitride, or cermet. (b) Furthermore, the electrode surface is coated with boron, aluminum, silicon, titanium, vanadium, chromium, zirconium, hafnium, tantalum, tungsten alone, alloys, and their nitrides or carbides in a thickness of 1 to 10 μm. (c) A method for improving the durability of an electrode, which comprises using dry coating such as sputtering, ion plating, or plasma CVD when performing the coating.