JP2013150992A - Build-up welding method by tig welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such the problem that conventionally, in the case when the build-up of stellite is performed by TIG welding, compared with oxy-acetylene gas welding, a penetration rate on the side of a base material is as high as 15±5%, thus prescribed hardness can not be obtained in one-layer build-up in which the base material metal has been subjected to dilution and there is a need of performing 2 to 3 layer build-up, and further, hardness is made low since there is no carburization phenomenon like gas welding, thus, in TIG welding, there is a need of performing multilayer build-up for reducing a preheating temperature and obtaining hardness, and underlaying of SUS based metal has been required for preventing cracks.SOLUTION: In TiG welding, the blending ratio of a shielding gas is controlled to CO2: 50 to 80% and Ar+He: 20 to 50%, thus consumption of carbon is prevented, and an action effect same as that of carburization in gas welding is exhibited. Further, liquid flux is applied to a base material and a welding rod, and welding is performed while spraying vaporization flux, thus the removal of the surface tension of molten metal and prevention of oxidation are achieved, the penetration rate of the base material is suppressed to ≤5% and the dilution of build-up metal by the base material metal is prevented, thus prescribed hardness can be obtained in a first layer.

Description

  The present invention relates to a method for preventing a decrease in hardness due to TIG welding and improving welding work efficiency. A shield gas containing carbon dioxide gas is blown into the liquid flux to vaporize it, and the vaporized flux is generated, and welding is performed while blowing this vaporized flux to the weld surface, thereby removing the surface tension of the molten metal and preventing oxidation to prevent oxidation. Allows prime. Moreover, it is related with the welding method which prevents the hardness fall by carbon shortage by supplying the carbon lost during TIG welding from a carbon dioxide gas, and carburizing.

As the shield gas welding method, there are CO2 gas arc welding, TIG welding, MIG welding, MAG welding, PTA welding method (powder overlay welding method) and the like. These are used as a conductor shielding gas mainly for preventing oxidation of the welded part by blocking oxygen in the atmosphere and maintaining the arc voltage. For example, in MAG welding, when the molecules of the shielding gas (CO2 + Ar + O2 + He) dissociate into atoms, the heat of dissociation is absorbed and the arc voltage is increased by nearly 30% (thermal pinch effect → arc contraction effect). I can plan. The thermal pinch effect means that heat is removed when diatomic molecules in the arc dissociate into atoms, and the arc is forcibly cooled by the shielding gas covering the arc. In the same way as shrinking, the arc is a phenomenon that attempts to shrink its cross-sectional area to suppress heat loss. Nitrogen and oxygen molecules absorb the heat of molecular dissociation and are separated into atoms by the arc voltage, but their chemical formulas are, for example, N 2 → N + N, O 2 → O + O. Since the dissociation heat is released when the atoms become molecules again in the vicinity of the weld base material, there is an effect of increasing the arc voltage. MAG welding is not suitable for manual welding because the radiant heat is so large that the welding operator cannot withstand. Mainly used for overlay welding by robot automation.

The shielding gas for TIG welding is Ar, He, Ar + He for aluminum alloys and copper alloys. For stainless steel, Ar, He, Ar + He. For austenitic stainless steel, Ar + O2 is used. For carbon steel and high tensile steel, Ar, He, Ar + O2, and Ar + He. Ar gas has the feature of floating the oxide film on the surface of the weld base metal due to the attack of magnetic wind and the large specific gravity, so it has a great shielding property on the weld surface due to the strong air flow, and is the basic shielding gas for TIG welding. It is used. As described above, TIG welding is a welding method that uses Ar gas as a basis and uses a mixture of He, H2, and the like according to the type of welding material, but does not use CO2.

In the conventional TIG welding hardfacing, the shielding gas is mainly Ar or He, and since no CO2 is used, there is no carburizing effect by the shielding gas. Conversely, when CO2 is used in TIG welding, CO2 → CO + O, CO → C + O, and the carbon of the welding rod and base material is burned, so that there is a problem that the carbon in the build-up portion decreases and the hardness decreases. However, if CO2 can be used as the shielding gas for TIG welding, the hardness can be increased by the carburizing effect by CO2 (carbon dioxide gas), and the effect of increasing the arc voltage by molecular dissociation heat can be expected. Furthermore, in terms of workability, Stellite build-up by TIG welding preheats the build-up base material to 500 ± 100 ° C, one hand has a TIG welding torch, and one hand continuously feeds with the left hand to dissolve the stellite rod. It is welding with severe thermal fatigue due to the radiant heat of the preheating burner. In addition, while turning the positioner on and off with the foot, concentrate the nerves so that the nest and pinhole are not formed, but if the nest and pinhole occur, the position is accurately memorized and the second layer It must float and disappear when welding. It is a welding that uses the whole body. The present invention is a welding method born to improve this adverse environment even a little.

When the hard build-up is performed by TIG welding, the first layer requires a build-up of two to three layers because the amount of penetration of the base material increases and dilution with the base material component is difficult to achieve a predetermined hardness. Since gas welding has a carburizing effect by a flame and a predetermined hardness can be obtained from the first layer, stellite buildup is usually performed by gas welding. In the build-up of Stellite by gas welding, flux is not used because it greatly dislikes defects such as nests and pinholes. This is because the unreacted flux causes defects because there is no ultrafine particle flux. Conventional fluxes include various inorganic compounds such as boric acid (H3BO3, 180-800 ° C), borax (Na2B4O7 · 10H2O, 741-1575 ° C), sodium fluoride (NaF, 870-676 ° C), boron oxide (B2O3, The recrystallization flux is mainly used by mixing 2 to 4 kinds of electrolytes such as 577 to 1500 ° C.), stirring the water as a binder to complete the chemical reaction and recrystallizing it. In the method using water as a binder, the generation of recrystallization flux is only a part, and even if the electrolyte is stirred using water as a solvent, the electrolyte remains in a solid state without being completely dissolved. The recrystallized flux and the residual electrolyte are dried and pulverized and used as a flux in the form of a paste. Such a paste-like flux has a large pulverized particle size. In the case of stellite welding, since the welding temperature is 1260 ° C. on average, it is necessary to coat 200 to 1500 ° C. where temperature oxidation starts with flux to make the build-up surface non-oxidized and to remove the surface tension. Since it is large, unreacted flux remains. Further, each component of the paste-like flux is dissolved and expands independently when reaching the respective melting temperature, and therefore, when preheated by the preheating burner flame, it is scattered between 300 to 500 ° C. For this reason, the paste-like flux does not stick to the welded surface in the form of glass and cannot fulfill the original function of the flux. Therefore, the paste-like flux is used only when floating a local nest or pinhole. For this reason, when gas welding stellite, there is a high risk of unreacted flux being caught in the welded portion, so that flux is not used, but various attempts to use flux have been proposed.

In Japanese Laid-Open Patent Publication No. 2010-005696 “Activated Flux for Tungsten Inert Gas Arc Welding for Steel”, silicon dioxide (SiO ₂ ), iron metasilicate (Fe ₂ SiO ₄ ), iron orthotitanate (Fe ₂ TiO ₄ ), metatitanic acid An active flux for tungsten inert gas arc welding (TIG welding) for steel containing iron (FeTiO ₃ ) and iron dititanate (FeTi ₂ O ₅ ) is shown. The flux is a suspension containing flux powder and an organic volatile solution such as ethyl alcohol, and is applied to the welded joint before welding. (1) The flux is not dissolved in the solution and is uniform. There is a problem that the reaction cannot be performed and the function as a flux cannot be sufficiently achieved.

In Japanese Laid-Open Patent Publication No. 2011-177769 “TIG Welding Method”, both ends of a welding target in a butt state without taking a groove in all-position welding in which a welding target having a thickness of 3 mm or more is fixed and the periphery is welded And a TIG welding method in which a deep penetration activator for TIG welding is applied to the outer periphery of the butt before welding. The penetration activator is an application of the activator disclosed in Japanese Patent Application Laid-Open No. 2010-005696, and a uniform reaction as a flux is difficult, and the flux itself may be involved to cause defects.

In Japanese Laid-Open Patent Publication No. 2004-283858, “TIG welding wire with excellent penetration characteristics”, one or two types of titanium oxide, zirconium oxide, chromium oxide, molybdenum oxide, silicon oxide and iron oxide are formed on the surface of the TIG welding wire. The TIG welding wire which coat | covered the film | membrane which consists of the above by the liquid phase deposition method is disclosed. The flux is a solid flux, and since each compound acts independently, a uniform reaction cannot be performed, so that there is a problem that the function as a flux cannot be exhibited.

The present inventor invented a method for welding by mixing a vaporized flux with a shielding gas in MAG welding, MIG welding, and carbon dioxide gas welding in Japanese Patent Application No. 2011-246151, “Semi-automatic arc welding method”. In stellite overlaying, it is necessary to first put the base material in a sweating state, so that it is difficult with a welding method in which an arc is generated by the weld metal itself. Therefore, stellite build-up welding is limited to gas welding or TIG welding.

For the build-up of stellite, methods such as gas welding, automatic TIG welding, and powder plasma build-up are used, but for the build-up of the valve stem and valve seat of the high-temperature and high-pressure valve, gas welding is advantageous. In particular, valve seats, etc., located in deep places, have become a work that builds up on the invisible parts by gas welding. Although a water-cooled blower burner is used, such a valve seat build-up worker is extremely short and is a technique that requires very experience. At present, the valve seat is cut into a ring and the valve seat is built up, and then it is confirmed that there are no nests and pinholes in the intermediate finish. After the ring-cut valve seat is connected by welding, stress annealing at 650 ± 50 ° C is performed. Final finishing. In the conventional TIG welding, there is a problem that such a complicated work process must be repeated because a predetermined hardness cannot be obtained unless at least three layers of the stellite rod are built up. Even in TIG welding, if the required hardness can be obtained in the first layer as in the case of gas welding, the process can be reduced and the cost can be greatly reduced.

The present inventor is disclosed in Japanese Patent Application Laid-Open No. 2011-088180 “Welding Flux and Welding Method”, alkali metal, alkaline earth metal, halogen, B, C, N, O, Si, P, S, Zn, Se, etc. A welding method in which a liquid flux produced by dissolving an electrolyte formed by combining at least two types of atoms in a solvent in a solvent such as alcohol or acetone is applied to the welded portion, and the liquid flux is vaporized. The inventors have invented a method of welding while spraying a composite shield gas generated by mixing the causticized flux with a shield gas or a mixed shield gas obtained by mixing a plurality of shield gases onto the welded portion. According to Japanese Patent Application No. 2010-200494 “Brassing flux and brazing method”, the liquid flux is filled into a vaporizer, and the vaporization is carried out by injecting a combustion gas such as propane (C3H6) or acetylene (C2H2). As a flux, a brazing method was invented in which the vaporized flux was blown and brazed while being heated to a burner of a brazing furnace and heating the brazing furnace. In Japanese Patent Application No. 2010-206271, “Fin Tube Manufacturing Method”, a fin tube is manufactured by high-frequency resistance welding of a fin and a tube. The vapor flux is filled in the vaporizer and gas is blown into the vaporizer. The fin tube manufacturing method which welds the said fin and the said tube while spraying the vaporization flux produced | generated by vaporizing the said liquid flux on a welding part was invented. Japanese Patent Laid-Open No. 63-12357, “Gas Shield Arc Welding” invented a welding method using a charged gas as a shielding gas. A welding method that further develops the present invention is disclosed in Japanese Patent Application Laid-Open No. 2011-098367, “Flux for welding overlay and welding overlay”, in which an inoculant is mixed into a precipitate flux generated by appropriately depositing a solute of liquid flux. As a gel flux, after applying the gel flux to a welding base material, the solvent of the gel flux is dried or burned and fixed as a solid flux to the buildup base material. We have invented a method of welding to a prime base material and a method of welding in a charging shield gas.

The present inventor disclosed in Japanese Unexamined Patent Application Publication No. 2009-090368 "Gas cutting vaporization flux" 8 to 25 in a solvent such as alcohol or acetone. Invented a gas cutting vaporization flux that is mixed by weight%, dissolved in a supercritical apparatus at a temperature of 300 to 400 ° C. and a pressure of 34.3 to 44.1 MPa to form a liquid flux, and gas is blown into the liquid flux for vaporization. . JP 2009-297782 A "Liquid flux production method and apparatus" disclosed in alkali metal, alkaline earth metal, halogen, B, C, N, O, Si, P, S, Cl, Zn, Se, etc. We have invented a method for producing a liquid flux in which an electrolyte formed by bonding at least two kinds of atoms among atoms is subjected to a magnetic field in a solvent such as alcohol or acetone and dissolved while stirring the solvent. In JP2010-100441A "Liquid flux production method and apparatus and liquid flux", atoms such as alkali metal, alkaline earth metal, halogen, B, C, N, O, Si, P, S, Zn, etc. In a method for producing a liquid flux, an electrolyte formed by combining at least two kinds of atoms is dissolved in a container containing a solvent such as alcohol while applying a magnetic field and rotating the solvent. Invented a method for producing a liquid flux in which an electrode is inserted and voltage is applied and a pulse voltage is applied. Combustion gases such as acetylene and propane in a liquid flux obtained by dissolving a flux used for brazing and gas cutting in alcohol, acetone, or a liquid obtained by mixing these in a publication "Japanese Patent Application Laid-Open No. 2009-233741" In the liquid flux vaporizing apparatus that vaporizes the liquid flux to generate the vaporized flux, a rotating cylinder having a plurality of rotating cylinder neodymium magnets disposed around is provided, and the rotating cylinder is provided at a rate of 60 minutes per minute. A liquid flux vaporization apparatus was invented that allows the vaporization flux to pass through while rotating it up to 200 times to take out the vaporization flux.

JP 2010-005696 PR "Tungsten inert gas arc welding flux for steel" Japanese Unexamined Patent Publication No. 2011-177769 “TIG Welding Method” Japanese Laid-Open Patent Publication No. 2004-283858 “TIG Welding Wire with Excellent Penetration Properties” Japanese Patent Application No. 2011-246151 “Semi-Automatic Arc Welding” Japanese Unexamined Patent Publication No. 2011-088180 "Welding Flux and Welding Method" Japanese Patent Application No. 2010-200434 “Flux for brazing and brazing method” Japanese Patent Application No. 2010-206271 “Fin Tube Manufacturing Method” Japanese Laid-Open Patent Publication No. 2009-090368 "Vaporization Flux for Gas Cutting" Japanese Laid-Open Patent Publication No. 2010-1000044 “Liquid Flux Manufacturing Method and Manufacturing Apparatus and Liquid Flux” Japanese Unexamined Patent Publication No. 2009-233741 “Liquid flux vaporizer” Japanese Unexamined Patent Publication No. 2011-088180 "Welding Flux and Welding Method" Japanese Patent Application Laid-Open No. 2010-269370 “Cutting Method of Thick Plate Material” Japanese Laid-Open Patent Publication No. 2010-1000044 “Liquid Flux Manufacturing Method and Apparatus” Japanese Unexamined Patent Publication No. 2009-233741 “Liquid flux vaporizer” Japanese Laid-Open Patent Publication No. 63-12357 “Gas Shield Arc Welding” Japanese Unexamined Patent Publication No. 2011-098367 "Welding Flux for Welding and Welding Method" Japanese Patent Application No. 2010-165565 Public Relations “Liquid Flux” Japanese Laid-Open Patent Publication No. 2009-156518 "Fusing Nozzle for Metal Body" Japanese Laid-Open Patent Publication No. 2009-297782 “Liquid Flux Production Method and Apparatus”

High temperature science, Nikkan Kogyo Shimbun High temperature engineering, Nikkan Kogyo Shimbun

In the CO2 welding method, MIG welding, MAG welding, and TIG welding, it is used that the arc voltage increases due to the heat of dissociation and decomposition when the molecular gas (CO2, N2, O2, H2) in the inert gas dissociates into atoms. Therefore, both welding methods can improve efficiency. TIG welding is used where high quality is required rather than high efficiency. However, since automation such as robotization is easy, both high efficiency and high quality can be satisfied. Problems in automating TIG welding are as follows. (1) Magnetic blow occurs along the periphery of the irregularities in the welding surface, base metal shape, welding burner, and welding rod automatic supply shape. (2) If there is a ferromagnet near the arc, the arc column will be pulled by the ferromagnet, and it will be difficult to homogenize the normal surface of the arc column due to a kind of magnetic wind. The adjustment of becomes strict. (3) When a magnetic blow occurs, the arc becomes unstable and welding defects such as partial melting, poor penetration, poor fusion, and poor bead shape are likely to occur. The present invention is for solving the above-mentioned problems.

The first solution is a method of TIG welding a hardfacing material as shown in claim 1, wherein the shielding gas contains 50 to 80% by volume of CO2, and the remainder is Ar or He or N2 or a mixture thereof. A mixed shield gas containing 20 to 50% by volume of gas, and after the mixed shield gas is mixed in a mixer, the mixed shield gas is blown into a liquid flux filled in a vaporizer to vaporize the liquid flux. A gas flux is formed, and a vaporized flux in which the gas flux and the mixed shield gas are mixed is generated. The vaporized flux is guided to the torch and welded while sprayed on the welding surface, and the liquid flux is applied to the welding surface and the welding rod. This is a TIG welding method in which welding is performed.

According to a second solving means, as shown in claim 2, a neodymium magnet is disposed in a cylinder at the tip of the torch, and a twist blade for imparting a turning force to the vaporizing flux is disposed in the cylinder. This is a TIG welding method.

According to a third solving means, as shown in claim 3, the mixer is provided with a supply port for the CO2, a discharge port for the mixed shield gas, and a venturi unit, and the venturi unit communicates with a plurality of gas pipes. An inert gas is supplied to the gas pipe and mixed with the CO 2 to generate the mixed shield gas, a mixing chamber is provided at the outlet of the venturi section, a neodymium magnet is provided in the mixing chamber, the mixing chamber This is a TIG welding method in which an oblique nozzle hole for rotating the mixed shield gas is provided on the outlet side of the metal, and a neodymium magnet is provided in the discharge port.

Usually, the shielding gas for TIG welding is Ar alone or a mixture of He and N2 with Ar as the main component. In the present invention, Ar gas is used in an amount of 20 to 50% by volume for stabilizing the arc voltage. The following effects are produced by mixing (volume%). (1) Excellent in arc stabilization. (2) Deep penetration can be achieved. (3) It is inexpensive. (4) CO2 functions as a carburizing gas and a shielding gas. (5) Since the heat of dissociation of the molecular gas can be used to the maximum, preheating can be kept low. (6) Since expensive Ar can be supplemented by CO2, the cost of the shielding gas can be reduced.

When CO2 and Ar are mixed in comparison with the case where Ar is used alone as the shielding gas, it becomes possible to suppress preheating by an amount that can increase the arc voltage by 20 to 30%, and the stellite buildup mainly composed of surface hardening. Can reduce the thermal fatigue of the welder. The vaporized flux is a mixture of a mixed shield gas and a gas flux obtained by vaporizing a liquid flux, and the gas flux is contained at a maximum of 5 wt%. Since the surface tension of the weld metal can be removed and oxidation can be prevented by the action of the gas flux, the build-up is completed 20 to 30% earlier, and the thermal fatigue of the operator can be reduced accordingly. Further, since the gas flux is contained at a maximum of 5 wt%, a magnetic field is generated around the arc in proportion to the welding current according to Fleming's law. Since ions such as Na, K, and B flow in the charged gas, the arc is tightened in the form of a magnetic ring, so that the wobbling is reduced, the welding surface is smoothed, and a beautiful overlay can be formed.

By applying liquid flux to the welding surface and welding rod in advance, (1) the welding surface is shielded from air and oxidation of the welding surface is prevented. (2) The liquid flux sticks thinly and strongly compared to the conventional solid flux. Therefore, since the surface tension of the molten metal is removed, the fluidity is improved, so that a weld metal that is difficult to form a nest and a pinhole is obtained.

Since CO2, Ar, N2, and He have different specific gravities, it is impossible to mix 100% with a conventional single gas flow meter and take it out as a mixed shield gas. Therefore, a new mixer is provided, and mixing is performed by sucking Ar, N 2, and He into the venturi part provided in the mixer, so that it is possible to obtain a completely mixed mixed shield gas. The venturi section is a mechanism for locally increasing the flow velocity by reducing the flow of the compressive fluid and lowering the fluid pressure as compared with the low speed section. The venturi section has a function of sucking in other fluids and can promote mixing of shield gas. Since the neodymium magnet is disposed in the mixing chamber or the like, the mixed shield gas is charged and activated. Therefore, the liquid flux filled in the vaporizer can be efficiently converted into a gas flux.

Conventional gases for TIG welding are expensive because they use rare gases such as He, Ne, Ar, Kr, Xe, and Rn of Group 18. Because it is chemically inert, it is said to be an inert gas, but when mixed with an inexpensive molecular gas such as CO2, the arc voltage is increased, and when mixed with a gas flux, it has a flux while being TIG welding. Arc brazing is possible. The conventional arc flame is blue and purple, and the green color due to the vaporization flux is added, so that it becomes a soft arc color instead of an intense arc color. Green is mainly ionization of B.

Since a neodymium magnet is disposed on the exit side of the torch, the vaporized flux can be magnetized and charged, so that the arc voltage is improved. Since the twisting blade can rotate the vaporization flux, the pinch effect of the arc can be improved.

These are the schematic diagrams of TIG welding. FIG. 3 is a cross-sectional view of the tip portion of the torch. Is a cross section of the tip of the torch. FIG. 3 is a cross-sectional view of a mixer. FIG. 6 is an arrangement view of oblique nozzle holes.

Embodiments of the present invention will be described with reference to claims and FIGS. 1, 2, 3, 4, and 5. FIG.

The first solution is a method of TIG welding a hardfacing material as shown in claim 1, wherein the shielding gas contains 50 to 80% by volume of CO2, and the remainder is Ar or He or N2 or a mixture thereof. It is a mixed shield gas containing 20 to 50 v% gas. After the mixed shield gas is mixed in the mixer 10, the mixed shield gas is blown into the liquid flux filled in the vaporizer 20 to vaporize the liquid flux. A gas flux is generated by mixing the gas flux and the mixed shield gas, and the vaporized flux is guided to the torch 30 and welded while being sprayed on the welding surface 60a. The welding surface 60a and the welding rod 50 are also welded. This is a TIG welding method in which the liquid flux is applied and welded.

The main shield gas for TIG welding according to the present invention is CO2, and Ar and He are mixed with CO2 and used as a mixed shield gas. In consideration of welding conditions such as the welding rod, base metal, and hardness, the composition of CO2 and Ar is adjusted. Normally, CO2, Ar, and He are supplied from the CO2 tank 01, Ar tank 02, and He tank 03. Shielding gases such as CO2, Ar, and He are once put in the mixer 10 and mixed. Since the shielding gas has a different specific gravity and is difficult to mix, the mixer 10 is provided with a venturi portion 11a to suck the shielding gas and stir each other to promote mixing. The mixer 10 is provided with a neodymium magnet 16 which is charged and activated when the shield gas passes through the magnetic field. The shield gas exiting the mixer 10 enters the vaporizer 20 as a mixed shield gas. The vaporizer 20 is filled with a liquid flux. Since the liquid flux is vigorously bubbled by the mixed shield gas, it is vaporized to become a gas flux. The gas flux contains an electrolyte component dissolved in the liquid flux together with the solvent of the liquid flux. The vaporization flux is a mixture of mixed shield gas and gas flux. The vaporizer 20 is provided with a neodymium magnet 16, and the liquid flux is charged and activated by the neodymium magnet 16. The vaporized flux exiting the vaporizer 20 is guided to the torch 40 via the vaporizer flux supply pipe 32 by the pipe 31 via the relay 30. A current is supplied to the torch 40 from the power source 70 via the cable 71. A water resistor 72 is provided in the power supply system to stabilize the current. As the welding base material 60, an engine cylinder valve 60 is shown as an example. The seat 60 a of the cylinder valve 60 is usually welded while being rotated by a motor 74. The positioner 73 is used to turn the rotation on and off. An arc 30a is formed by the torch 40 and the vaporizing flux 30b, and the welding rod 50 is welded to the sheet 60a.

As the vaporizer 20, those disclosed in Japanese Patent Application Laid-Open No. 2009-233741 “Liquid Flux Vaporizer” and Japanese Patent Application No. 2011-246151 “Semi-automatic arc welding method” invented by the present inventors can be used. The vaporizer 20 includes a vaporizer 21, an air supply pipe 22 that supplies a shielding gas to the vaporizer 21, an exhaust pipe 23 that extracts a generated vaporized flux, and a plurality of magnets 16.

In the case where the distance from the vaporizer 20 to the torch 40 is 5 m or longer, it is preferable to prevent recrystallization by passing the relay 30. The repeater 30 can be the same as the repeater described in Japanese Patent Application Laid-Open No. 2010-269370, “Thick Plate Cutting Method”. A repeater 30 incorporating neodymium magnets is installed at appropriate intervals in the middle of the supply pipe 31 from the vaporizer 20 to the torch 40. One repeater 30 is preferably provided within at least 10 m. The neodymium magnet 16 preferably has a magnetic force of at least 30000 gauss. In order to widen the contact area between the neodymium magnet 16 and the fusing gas, it is preferable to make the vaporization flux flow path in the repeater 30 as long as possible by providing many folds in the repeater 30 or making it spiral. Various internal structures of the repeater 30 are proposed depending on the strength and arrangement of the neodymium magnets 16, but the present invention is not limited by the difference in the internal structure of the repeater 30.

As shown in Japanese Laid-Open Patent Publication No. 2011-088180 “Welding Flux and Welding Method” and Japanese Patent Application No. 2011-246151 “Semi-Automatic Arc Welding Method”, the present inventor also uses conventional Ar-based TIG welding. It is effective to use vaporization flux. In a welding assembly factory or the like that uses a large amount of Ar, liquid Ar may be evaporated and connected to each automatic welding machine through factory piping. In that case, it is not economical to place the vaporizer 20 individually near each automatic welder. An efficient method is to arrange the vaporizer 20 in the Ar main pipe, mix liquid flux with Ar, and send it to each automatic welding machine. Therefore, when there is a distance of 10 m or more from the vaporizer 20 to the automatic welder, the vaporized flux may be recrystallized. For this reason, in order to prevent recrystallization of the gas flux component in the vaporized flux, it is necessary to apply vibration due to a strong magnetic field, so the relay 30 is passed before entering the TIG welding machine. Since recrystallization of the vaporized flux cannot be completely prevented, it is necessary to periodically clean the piping from the vaporizer 20 to the automatic welding machine.

In the overlay welding by TIG welding in the present invention, CO2 is used. In the following, the stellite overlay will be described as an example. CO2 (CO2 gas) is decomposed in two stages, CO2 → CO + O ↑, CO → C + O ↑, and carburized by gas welding by putting C (carbon) into the deposit metal surface of the stellite overlay. Has the same effect as Since it is difficult to achieve high hardness with a single layer in normal TIG welding, carbon is added to the stellite rod of TIG welding to an excess of 33 to 35 wt%, and tungsten is added to make a lot of carbides. Therefore, Mo is increased, and Ni is added up to 1.5% in order to increase toughness. However, compared with gas welding, the amount of carbon is still low, and it takes 2-3 layers to obtain the required hardness. As a result, the cost of stellite rods increases, and the build-up time is also increased by 1 layer of gas welding. It was no longer a big difference. The reason why the carbon content of the stellite rod is increased by 33 to 35 wt% is that carbon burns with high heat during welding, but there is a high risk of cracking if the thermal management is poor. On the other hand, as in the present invention, a liquid flux is applied to the TIG welding rod itself, a liquid flux is applied to the welding surface and the welding rod, and a vaporized flux containing a gas flux of a maximum of 5 wt% is sprayed on the welding surface. By welding, conventional stellite NO6 can maintain the same hardness as gas welding from the first layer. Stellite build-up is suitable for gas welding, but experienced welding workers are getting older and tend to be lacking year by year. Nurturing a welding worker requires many years of experience, and it is a poorly established task for young people today. In TIG welding, preheating is as high as 500 to 600 ° C., and gas welding is as high as 800 to 900 ° C., which is also the greatest condition that causes a shortage of technicians. In the stellite build-up by gas welding, the 1st layer build-up prevents the base material from oxidation, and even if a nest or pinhole can be made, the 1st layer builds up quickly as it is, and when the 2nd layer is built thin, these nests And pinholes are lifted off with a neutral flame or acetylene heating flame and erased, so that it is possible to build up with few defects. When depositing stellite by TIG welding, if the inert gas is made 100% Ar seal as in gas welding, the molten metal tends to become a sphere due to surface tension. As a result, the base material is lifted. At this time, since the welding rod metal is thinned by the base metal, the hardness is lowered and the variation is caused. In the case of automation, the correction work of the nest and pinhole is a technical bottleneck. When welding is performed while a skilled person confirms with the eye, the heating condition can be determined by a momentary judgment and the nest and pinhole are lifted, but it is a very difficult problem to perform such processing by automatic welding. In the present invention, the gas flux is mixed with the mixed shield gas to make the vaporized flux, so that the flux component removes the surface tension of the molten metal and also acts to prevent oxidation and clean up, so that the nest and pinhole can be easily levitated. It is possible to erase it. For this reason, a predetermined hardness can be obtained by one build-up operation and automation is facilitated.

As an example, the build-up of the engine valve seat 60a in gas welding or TIG welding will be described. Although stress due to buildup remains from the welding start site to the end site, particularly large concentrated stress remains at the welding end site (end portion). For this reason, in order to prevent the 2nd crack of a joint, the method of heating up and heating a little before a joint is taken. In this way, since the weld joint is melted twice, in the case of gas welding, the heating flame is made a neutral flame, so that excessive carburization is prevented and stress is released from the advance portion to the fillet in a triangular shape. Since TIG welding cannot adjust the flame like neutral flame, it covers by escaping with a crater current of 30-50 amps, but in order to reduce the current, the “tanned weld bead” has a triangular shape of 2-3 cm. Subsequently, the carbon burns and the hardness decreases. When the current is dropped, the melting of the melted bead is also worsened and the flow is further worsened. In the present invention, CO2 is mainly mixed with Ar, He, and N2 as a shielding gas for TIG welding to form a mixed shielding gas, and a liquid flux is vaporized with this mixed shielding gas to obtain a gas flux, and the mixed shielding gas and the gas flux are mixed. Generated vaporization flux. The vaporized flux is mixed with a gas flux of a maximum of 5 wt%, and when the vaporized flux is sprayed on the welded portion, the gas flux in the vaporized flux sticks to the weld bead surface in a glass shape. Since the gas flux removes the surface tension of the molten metal (deposit metal), the fluidity is improved. A crater dent is generated at the end of welding in TIG welding, but this dent causes welding defects such as weld cracks, so it is necessary to make it as small as possible. The process of filling this dent is called crater process. In the TIG welding method according to the present invention, since the surface tension of the molten metal is removed and the fluidity is improved by spraying the vaporized flux onto the welding surface and applying the liquid flux onto the welding surface and the welding rod, no crater is generated. Compared to the conventional crater treatment, it is a significant advance, and it has become possible to prevent the second crater cracking of the weld joint 100%.

The build-up of stellite in TIG welding and gas welding is the same, and the build-up thickness of a single bead is 1.5 to 4.5 mm up to a rod diameter Φ6 mm, and about 2.5 to 6 mm at a rod diameter Φ8 mm. The buildup width is 20 to 30 mm. When a predetermined build-up width cannot be covered with a single bead, the second layer overlaps 3 to 4 mm in the second layer. The lapping part is easy to form nests and pinholes due to surface tension and oxide film. In gas welding, in order to float these nests and pinholes in the second layer, the flame burner is shaken strongly to the left and right to break the surface tension and lift it. There is a possibility that over 45 years old when the function of eyes weakens may be overlooked, and stellite build-up by gas welding becomes difficult as it gets older.

Even in the stellite build-up by gas welding, build-up welding superior to the conventional one can be performed by using the vaporization flux. The inventor of the present invention invented a method for producing a liquid flux in Japanese Laid-Open Patent Publication No. 2010-1000044 “Liquid Flux Production Method and Apparatus”. This is a method in which several kinds of inorganic compounds are mixed in a hydrocarbon solvent such as alcohol, acetone, glycerin (C3H8O3), ethylene glycol (C2H6O2), and dissolved while applying a pulse current in a strong magnetic field. Liquid flux can be generated at normal temperature and pressure, and it is safe and pollution free. In addition, the present inventor invented a method of generating a vaporized flux by injecting a combustion gas such as acetylene into a liquid flux and evaporating it in Japanese Laid-Open Patent Publication No. 2009-233741 “Liquid Flux Vaporizer”. This method can be applied to gas welding of stellite, and the vaporized flux mixed in the welding flame sticks to the weld surface of the metal base at high temperature to prevent oxidation, and further dissolves the stellite molten metal surface. Since it is coated with a glassy film to prevent oxidation and remove surface tension, a smooth weld surface free of nests and pinholes can be obtained. The vaporized flux mixed with the acetylene gas is charged when it passes through a strong magnetic field at random, so that the gas kinetic energy becomes a single aurora particle state and is ejected from the combustion burner.

In the TIG welding of the present invention, since vaporized flux is contained in the arc, it is possible to easily remove surface tension and prevent oxidation without requiring welding skills, and the nest and pinhole can easily float and flow automatically. In the gas welding, when the overlap portion is welded, it is switched to a neutral flame to prevent excessive hardness due to excess carbon, but it is technically difficult to construct with a bead width of 20 to 30 mm. In the case of fully automatic TIG welding, it can be easily done by turning on and off the crater current only at the lap portion. Since the lap part melts twice, it is necessary to reduce excess carbon by switching to a neutral flame in gas welding, but in the case of TIG welding, on the contrary, carbon decreases and the hardness decreases. In the TIG welding of the present invention, vaporized flux is used, and this vaporized flux is mixed with gas flux in a mixed shield gas mainly composed of CO2, so that the carbon separated from CO2 penetrates into the molten metal and has a hardness. There is no low rainfall. Further, since the nest and pinhole are easily lifted and the flow is improved by removing the surface tension near the second weld, the crater treatment work is not required.

In the gas welding stellite heap, the first layer is piled up in a “sweat” state, so the base metal is melted by only 5 to 6%, and the hardness is low, but in the case of TIG welding, the base metal is 15 to Since the base metal component serves to dilute the welding rod component in order to dissolve 20%, the hardness decreases. In addition, since the hardness drop due to the combustion of carbon also overlaps, TIG welding maintains the hardness by overlapping two layers and three layers. As a result, TIG welding has a drawback that it cannot retain hardness unless it is built up in large quantities. This leads to an increase in the cost of the welding rod and inefficiency of work. In the TIG welding according to the present invention, as a shielding gas, CO2 is mainly mixed with Ar, He, and N2, and mixed carbon gas by separation of CO2 is injected into the molten metal to prevent decarburization. Since the surface tension of the molten metal is removed and the fluidity is improved by the action of the gas flux to prevent oxidation of the weld buildup surface, the buildup after the second layer flows thinly and well, so conventional TIG welding Compared with the method of building up, it is possible to reduce the stellite rod for building up by nearly 40%.

In both gas welding and TIG welding, it is essential to relieve the concentrated stress by overlapping the lap portion of the welding end portion. In the case of gas welding, the flame is released to the corner while gradually reducing the hardness of the melted portion twice while wibbing the torch as a neutral flame. Since TIG welding cannot be used except for the crater current, if the main current 150A → 50A is dropped rapidly, a dent will be generated at the end of the weld, leading to crater cracking. In the case of automatic TIG welding, the same operation as gas welding can be incorporated into the controller, so it is possible to narrow the arc by adjusting the current and voltage, and dent cracking occurs by backing up once and building up again on the final bead. Can be prevented. This is a conventional Ar-based TIG welding, and skilled techniques and automation measures are required to prevent crater cracking. On the other hand, in the TIG welding of the present invention, since the molten metal automatically flows due to the gas flux action in the vaporized flux, current adjustment is not required even in manual TIG welding, and there is no crater cracking by simple adjustment of the torch gap. Welding is possible. Since welding is performed in flux while being TIG welding, the surface tension removal build-up is achieved, and the dilution of the base material can be suppressed to 5% or less, so that only one layer build-up has the same hardness and weld surface as gas welding. be able to.

When building up stellite, it is important to treat stellite so that there is no difference in the thermal expansion coefficient between the stellite and the base material. As an example, when SCM-435 valve seats are built up, SUS309 is built up as an intermediate layer, the surface layer is processed smoothly, and Stellite NO6 is built up by TIG welding, so that it is difficult to crack even if the preheating is lowered. One method is to build up an intermediate metal for absorbing stress against such elongation and contraction. The cushion build-up method is mainly applied to wear-resistant build-up, but the combination of metals with close expansion coefficients is the basis of welding. The thermal expansion coefficient of main metals is shown below. Stellite NO1 is 12.3 × 10E-6 at 100 ° C., Stellite NO2 is 12.3 × 10E-6 at 100 ° C., Stellite NO6 is 13.9 × 10E-6 at 100 ° C., and Stellite NO12 is 11.3 at 100 ° C. 9 × 10E-6, Stellite NO32 is 11.0 × 10E-6 at 100 ° C., and Stellite NO21 is 14.0 × 10E-6 at 300 ° C. Carbon steel (0.2C) is 11.7 × 10E-6 at 100 ° C., carbon steel (0.3C) is 12.1 × 10E-6 at 100 ° C., and SUS304 (18-8) is 17.degree. 3 × 10E-6, SUS316 (18-12) is 16.0 × 10E-6 at 100 ° C., SUS309 (25-12) is 14.9 × 10E-6 at 100 ° C., and SUS410 (BCr) is 100 ° C. It is 9.9 × 10E-6.

The present invention is a method of overlaying stellite by TIG welding. In the case of TIG welding of stellite, the liquid flux is vaporized with CO2 + Ar inert gas, but when the vaporized flux flows from the welding torch in a charged state, the arc is demagnetized. The arc voltage due to the addition of the pinch effect due to and the dissociation energy of the molecular gas rises by up to 30%. This leads to a drop in welding current, so that it is possible to suppress preheating and to reduce worker fatigue due to heat radiation of the weld base material.

The present inventor disclosed in Japanese Patent Application No. 2011-246151 “Semi-Automatic Arc Welding”, mixing vaporized flux in shielding gas, applying liquid flux to the supply wire side and welding to weld wire metal yield after welding. Invented a method to increase the content of 5 to 10%. In order to apply the liquid flux to the welding rod by semi-automatic TIG welding, it is possible to apply the liquid flux to the feed roller of the welding rod. It is possible to maintain the same hardness as that of gas welding in the first layer by using a mixture of two kinds of shielding gas, CO2 + Ar, and applying a liquid flux with a band electrification flux and a feed roller.

The inventor disclosed in Japanese Patent Publication No. 63-12357, “Gas Shield Arc Welding”, pinched the CO 2 arc welding shield gas several times in the magnetic field of the ferrite magnet to charge CO 2 like an aurora. Realized that spatter of 30% or more is reduced due to the effect of arc constriction. The vaporized flux is charged by passing through a charging zone of the vaporizer to a CO2 + Ar two-type mixed gas containing about 5% of the vaporized flux in the inert gas of TIG welding. Therefore, the arc voltage is increased even with TIG welding.

According to Non-Patent Document 01 “High-temperature science”, there is a surface treatment hardening method that can easily carbonize and nitride by chemical reaction when ammonia gas is sealed on the surface of a steel slab and blow-discharged. Carburizing and nitriding can be performed at the same time by mixing the vaporized flux with the three mixed gases of CO2 + Ar + 2NH3. For example, when sodium fluoride and sodium hydrogen fluoride are mixed as the main component of the vaporized flux, H6 ↑ in 2NH3 reacts with these gases. Therefore, there is no danger of explosion. When ammonia gas is not used, N2 gas may be mixed. In this case, the heat of dissociation when N2 undergoes molecular dissociation is smaller than the heat of dissociation when ammonia undergoes molecular dissociation (2NH3 → 2N + 6H).

According to Non-Patent Document 02 “High Temperature Engineering”, chemical reaction energy is said to be activation energy during the changing process. The combustion reaction formula of combustible gas is as follows. Hydrogen is H2 + 1 / 2O2-> H2O, methane is CH4 + 2O2-> CO2 + 2H2O, and acetylene is C2H2 + 5 / 2O2-> 2CO2 + H2O. The heat generated by reacting with oxygen and burning is applied to welding and fusing. Rather than instantaneously melting a metal, it is a fusing that cuts with a heat of oxidation reaction by the power of oxygen as a liquid metal over a certain amount of preheating and time. On the other hand, it is welding that prevents oxygen from entering and protects the liquid metal from oxidation. In order for each atom of the liquid metal to change its position every moment by thermal motion to create a re-atomic arrangement, it is necessary to make it easy to connect atoms with each other by the function of the flux. Since the vaporization flux used in the present invention is a gas and enters between dissolved molecules, it facilitates the connection between atoms. The removal of the force, that is, the surface tension generated during the recombination between molecules and atoms by vaporization flux, helps the flow of molten metal and the atomic bonds.

The present inventor disclosed in Japanese Unexamined Patent Publication No. 2011-088180 “Welding Flux and Welding Method” of elements such as alkali metals, alkaline earth metals, halogens, B, C, N, O, Si, P, Cs, Se, etc. Rotate and dissolve the liquid flux by applying a strong magnetic field in a solvent in which several kinds of liquids such as alcohol, acetone, glycerin (C3H8O3), and ethylene glycol (C2H6O2) are mixed. Generated. In Japanese Patent Application No. 2010-200494, “Flux for brazing and brazing method”, a liquid flux is filled into a vaporizer and a combustion gas such as propane or acetylene is blown to vaporize to generate a vaporized flux. We have invented a technology that prevents crystallization from being recrystallized in pipes and hoses during transportation by adding kinetic energy by charging. JP-A-63-12357, “Gas shield arc welding method”, succeeded in reducing spatter by the action of constricting the arc by the pinch effect by charging the shield gas.

The points of TIG welding of the present invention are (1) using CO2 as a shielding gas, (2) welding while spraying vaporized flux on the welding surface, and (3) applying liquid flux to the welding surface and welding rod. Welding. When the vaporized flux is applied to TIG welding, the arc can be constricted, so that the dilution of the base metal can be reduced due to the preheating increase of the arc heat and the lowering effect of the welding current, and the hardness decrease of the built-up portion is reduced. By generating a liquid flux on the basis of the publication “Japanese Patent Application Laid-Open No. 2011-088180” “Welding Flux and Welding Method”, it is possible to make a liquid flux from a liquid state to a jelly state. The liquid flux can completely dissolve the electrolyte by stirring with a magnetic field applied to a solvent such as alcohol. Liquid or jelly can be used as the liquid flux applied to the weld overlay. For example, the jelly-like flux becomes a jelly when 5 wt% of hydrogen silicofluoride (H 2 SiF 6, 40 wt% concentration) and 10 wt% of ethyl silicate (Si (OC 2 H 5) 4) are added to the liquid flux and reacted for 24 hours. Further, when 5 wt% of hydrogen silicofluoride (H 2 SiF 6, 40 wt% concentration) and 10 wt% of tetraethoxysilane ((C 2 H 5 O) 4 Si, concentration 28 wt%) are added to the liquid flux and stirred well, a liquid flux can be generated. In this case, the liquid flux has a high viscosity and a jelly shape. As described above, the liquid flux is basically a liquid, but the viscosity varies depending on the compound to be mixed, and in some extreme cases it may be in a jelly form. This is collectively referred to as a liquid flux. It is preferable to determine the viscosity of the liquid flux in consideration of various conditions such as a weld base material, a weld metal, and a welding posture. Since the liquid flux is a particle size flux of 2000 mesh or less, even if it is thinly applied to the stellite surface, it does not turn 100%, so it becomes a transparent glass-like non-oxide film and sticks. Therefore, if it is uniformly applied, it serves both as prevention of oxide film and removal of surface tension. In TIG welding, a vaporization flux that is a mixture of a maximum of 5 wt% gas flux in shielding gas (mixed gas of CO2 and Ar, He, etc.) is blown onto the welding surface, so that it is close to gas welding due to the flux function of the gas flux. Thus, the original hardness of stellite can be maintained even with a buildup of one layer of TIG welding. For example, if Stellite NO6H is used, Hs60 ± 3 is possible in the first layer.

The vaporization flux applied to the TIG welding of the present invention can also be applied to PTP. The present inventor applied a “gas shield arc welding method” disclosed in Japanese Patent Laid-Open No. Sho 63-12357, and applied a strong magnetic field to NN, SS in a Japanese Patent Laid-Open No. 2009-233541 “Liquid Flux Vaporizer”. A liquid flux is filled in a vaporizer having a structure in which a magnetic field is rotated by a mutual demagnetizing field by forming a multistage layer of 8 to 10 layers by a combination of the demagnetizing fields of each other, and a liquid flux is injected by blowing shield gas (CO2 + Ar). Is vaporized to generate a vaporized flux in which a shield gas and a gas flux in which a liquid flux is vaporized are mixed. Even in PTP build-up, the shielding gas (CO2 + Ar) passes through the vaporizer and creates a pinch effect that squeezes the arc due to the charging effect of the strong magnetic field, so that any metal can be dissolved because the plasma arc can be raised to nearly 5000 ° C compared to gas welding. . In order to further narrow down the plasma arc by the pinch effect, the current drop is 20 to 30 A compared with the conventional PTP welding method mainly composed of Ar gas. Due to this effect, dilution due to excessive melting of the build-up base material can be suppressed, so that high hardness can be obtained from the first layer.

Since the present inventor's Japanese Unexamined Patent Publication No. 2009-090368 “Vaporization Flux for Gas Cutting” removes the surface tension of the molten metal at the time of gas cutting and cuts by suppressing the oxidation reaction, the flow of molten metal on the cut surface is fast. As a result, the cutting speed is increased and, at the same time, the cutting ability of a thicker plate thickness is increased when the same fusing device is used. This is because the surface tension removal and anti-oxidation functions act because the vaporized flux is coated on the surface of dissolved iron (FeO, Fe3O4, Fe2O3). The common flux conditions for welding and cutting are as follows. (1) It has the effect | action which removes and cleans the oxide of the base material surface. (2) It has activity in the target temperature range. (3) It has the effect | action which promotes the fluidity | liquidity of a melted metal, and a ductility. (4) Keeping the antioxidant to the target melting temperature. (5) Do not become a hazardous substance when it becomes residual residue or slag. Both cutting and welding use flux to remove the surface tension of molten metal to improve the flow of molten metal and to prevent oxidation of molten metal once it leads to improved quality and efficiency of the cut surface and weld surface Is common.

In stellite welding by TIG welding, a mixer is passed as a shielding gas, this gas is introduced into the vaporizer as a mixed gas of 2 to 3 types, and a shielding gas containing a vaporization flux of up to about 5% is used in the mixed shielding gas. This improves the effect of increasing the arc voltage by cleaning the base metal surface during welding and removing the surface tension, and pinching effect in the arc by charged gas, and prevents decarburization by the carburizing effect of CO2 → CO + O ↑ → C + O ↑. To do. In order to cover the combustion carbon by TIG welding, the carbon content of the welding rod is increased by nearly 30%, but compared with gas welding, the unused portion of the welding rod after use (residual portion at the end) is managed. Sorting by welding rod type is difficult. Since the welding rod can be joined during welding by the welding rod continuous joining device, it can be used as a continuous rod 100%.

The second solving means is that, as shown in claim 2 and FIGS. 1, 2, and 3, a neodymium magnet 16 is disposed in a cylinder 35 at the tip of the torch 30, and the vaporization flux 30b is swirled in the cylinder 35. This is a TIG welding method in which a twist blade 33 for applying a force is provided.

The TIG welding torch 30 is fed to the tungsten electrode 34 by a power supply cable 71 for generating an arc. The tungsten electrode 34 is insulated by a collet 31. When the tungsten electrode 34 is energized, an arc 30 a is generated between the tungsten electrode 34 and the base material 60. The arc 30a is one in which the vaporized flux is in a plasma state at a high temperature. The welding rod 50 is melted by the high-temperature arc 30 a to harden and build up 36 on the base material 60. The neodymium magnet 16 charges the vaporization flux 30b to activate it. When the vaporized flux 30b is charged, an electromagnetic force acts on the vaporized flux 30b, and the vaporized flux 30b is strongly attracted to the arc 30a and the base material 60. Therefore, the electromagnetic pinch force of the arc 30a is improved, the temperature of the arc 30a is increased, and the welding efficiency is improved. According to Fleming's left-hand rule, an electromagnetic force directed toward the center acts on the arc 30a. When this electromagnetic force is strong, the droplets of the welding rod 50 are finely torn and become shower-like, resulting in welding with less spatter and fewer defects. In order to improve the pinch force of the arc 30a, a twist blade 33 is provided in the torch cylinder 35 so that the vaporized flux 30b concentrates on the arc 30a. The twisting blade 33 is arranged so that the vaporization flux 30 b is swirled around the arc 30 a and concentrated on the tungsten electrode 34.

The vaporized flux 30b is magnetically charged by the neodymium magnet 16 attached to the cylinder 35 located at the tip of the nozzle 30 and further rotated by the twisting blade 33, so that the vaporized flux 30b is concentrated on the tungsten electrode 34. The ionized vaporized flux spouts 8-20 liters per minute. Since it is not manually held by a human for automatic TIG welding, it does not matter if it is heavy. The arc 30a is forced to be a downward arc 30a by a magnetic field pinch force. It is possible to obtain a stable surface by taking measures against magnetic wind.

The inventor of the present invention invented Japanese Unexamined Patent Publication No. 2009-156518 “Fusing nozzle for metal bodies” (Japanese Patent No. 4736100) as a gas cutting nozzle. In a fusing nozzle for a metal body in which a nozzle shaft core portion is a fuel flow path, and an auxiliary combustion gas flow path is formed around the fuel flow path, a fixed helical throttle slit flow path is fixed to the auxiliary combustion gas flow path, and the helical throttle slit is downstream thereof. The flow path is a fusing nozzle having a rotating spiral slit flow path in the reverse spiral direction. The present inventor further invented Japanese Patent Application Laid-Open No. 2009-255105 “Fusing nozzle for metal bodies”. In the triple-nozzle metal fusing nozzle in which the nozzle shaft core portion is the secondary oxygen gas nozzle and the fuel gas nozzle and the primary oxygen gas nozzle are formed around it, the gas inlet is conical at the front of the fuel gas nozzle. A plurality of flow paths of widened straight grooves are arranged along the circumference, and swirl flow formation holes that communicate with the straight grooves and inject obliquely along the inner circumference of the secondary oxygen gas nozzle tip are provided at predetermined intervals, and go straight A conical nozzle that forms a conical space extending toward the outer periphery is provided at the outlet of the groove, and a plurality of slit spirals are formed at the front of the primary side oxygen gas nozzle with a wide angle at the gas inlet and gradually decreasing toward the outlet. A fusing nozzle is provided with a swirl flow forming nozzle provided with grooves along the circumference. This uses the high pressure oxygen pressure to rotate the cutting flame to forcibly raise the flame temperature by the flame pinch effect. When a pinch force is applied, the arc is forcibly tightened, so the temperature becomes higher and the fluctuation of the arc due to the magnetic wind is eliminated. In the case of full automation, 6-8 rotating blades in the nozzle skirt part are rotated by an air motor or motor from the outside of the skirt, forcing rotation to increase the straight running force due to the gas rotational force, so measures against magnetic wind Is possible. In the TIG welding torch 10 of the present invention, a method of improving the pinch force of the arc 30a by applying a turning force to the vaporizing flux 30b applies a flame pinch force caused by turning of combustion gas in fusing.

  As the third solution means, as shown in claim 3 and FIGS. 1, 4 and 5, the mixer 10 is provided with the CO2 supply port 14, the mixed shield gas discharge port 18 and the venturi section 11a. The short tube 11 communicates with a plurality of shield gas supply ports 12 and 13, and Ar, He, and N 2 are supplied to the shield gas supply ports 12 and 13 and mixed with the CO 2 to mix the mixture. A shielding gas is generated, a mixing chamber 15 is provided at the outlet of the short tube 11, a neodymium magnet 16 is provided in the mixing chamber 15, and the mixing shield gas is rotated on the outlet side of the mixing chamber 15. This is a TIG welding method in which an oblique nozzle hole 17a is provided in the flange 17 and a neodymium magnet 16 is provided in the discharge port 18.

CO2 enters from the CO2 supply port 14, and the flow velocity is increased by the venturi section 11a provided in the short pipe 11 in the mixer 10. For this reason, since the pressure in the venturi section 11a is reduced, shield gas such as Ar and He is sucked from the shield gas supply ports 12 and 13 and mixed with CO2 to become mixed shield gas. A plurality of shield gas supply ports can be provided according to the type and amount of shield gas. When the mixed shielding gas passes through the mixing chamber 15, the speed decreases and mixing is promoted, and the mixed shielding gas is charged and activated by the neodymium magnet 16. The flange 17 is provided with an oblique nozzle hole 17 a, and the mixed shield gas is rotated and mixed thoroughly, and is charged by the neodymium magnet 16 in the outlet pipe 18. The mixed shield gas enters the vaporizer 20 after being charged in the mixer 10, enters into the liquid flux and becomes bubbles, and the mixed shield gas vaporizes the liquid flux to become a vaporized flux. Therefore, the vaporized flux is a mixture of gas flux generated by vaporizing the mixed shield gas and the liquid flux. In the gas flux obtained by vaporizing the liquid flux, an electrolyte (solute) component dissolved in the liquid flux is vaporized and mixed together. The mixed shield gas contains about 5 wt% of gas flux. The vaporized flux is charged when passing through the neodymium magnet 16 in the vaporizer 20, and blown out of the TIG welding torch 40, so that a magnetic field is generated according to Fleming's left-hand rule. The 40,000 Gauss neodymium magnet 16 disposed in the cylinder 35 at the tip of the torch is tightened by the magnetic flux of the vaporized flux 30b, so that the magnetic wind that causes the arc to stop is stopped. Further, the charged vaporization flux 30b is forcibly swirled by a twisting blade 33 disposed on the cylinder 35 at the tip of the torch, so that a vortex is formed and the arc 30a is fastened by a pinch force caused by the vortex. Conventionally, since the automatic feeding device of the welding rod 50 leads to the disturbance of the magnetic field, it has been extremely difficult to adjust the build-up surface 60a and the arc 30a of the TIG welding torch, but (1) forced swirling of the vaporizing flux 30b (2) Pinch force increase due to strong magnetic field zone by neodymium magnet 16, (3) Pinch force increase due to action as magnetic field absorption particles by mixed shield gas in vaporization flux 30b, and (4) Magnetic field lines due to gas flux in vaporization flux 30b. Since the pinch effect due to the action as absorbing particles overlaps, the problem of the wobbling of the arc 30a due to the magnetic wind has been solved. Compared with welding using 100% Ar gas as a conventional shielding gas, the Hs hardness is increased by 18 ± 3.

Conventional main gases of TIG welding are mainly Ar and Ar + He, and are expensive. In MAG welding, Ar, He, CO2, O2, and N2 are mixed and used as a combination of molecular gases. However, in TIG welding, if CO2 is used as the shielding gas, oxidation due to CO2 → CO + O becomes a problem. In the TIG welding of the present invention, CO2 is mainly used as a shielding gas. Therefore, in the conventional flow meter separation and mixing, the specific gravity separation of the gas is intense, and the flow rate of a light gas such as He increases, and gas separation by convection occurs at the tip of the torch 40. CO 2, Ar, He, etc. are mixed by inhaling 2 to 4 types of shield gas from the shield gas supply ports 12, 13 of the mixer 10 into the venturi section 11 a, so that a uniform mixed shield gas can be generated. . A neodymium magnet 16 is incorporated in the mixing chamber 15, and the mixed shielding gas becomes a kind of magnetic wind. In addition, the mixed shield gas in the mixing chamber 15 is given a swirl force by the oblique nozzle holes 17a, so that it is mixed more effectively.

01: CO2 tank 02: Ar tank 03: He tank 10: Mixer 11: Short pipe 12: Shield gas supply port 13: Shield gas supply port 11a: Venturi section 14: CO2 supply port 15: Mixing chamber 16: Neodymium magnet 17 : Flange 17a: Oblique nozzle hole 18: Mixed shield gas outlet 20: Vaporizer 21: Vaporizer vessel 22: Air supply pipe 23: Exhaust pipe 30: Repeater 30a: Arc 30b: Vaporization flux 31: Pipe 32: Vaporization flux supply Tube 33: Twist blade 34: Tungsten electrode 35: Cylinder 36: Hardening 40: Torch 50: Welding rod 60: Base material (cylinder valve)
60a: welding surface 70: power supply 71: cable 72: water resistor 73: positioner 74: motor

Claims (3)

In the method of TIG welding the hardfacing material, the shielding gas contains 50-80 v% of CO2, and the remainder is mixed shielding gas containing 20-50 v% of Ar, He, N2, or a gas obtained by mixing these, After the mixed shield gas is mixed in a mixer, the mixed shield gas is blown into the liquid flux filled in the vaporizer to vaporize the liquid flux to form a gas flux, and the gas flux and the mixed shield gas are mixed. A TIG welding method comprising: generating a vaporized flux, welding the vaporized flux to a torch and spraying the vaporized flux on a welding surface, applying the liquid flux to the welding surface and a welding rod, and welding. 2. The TIG welding method according to claim 1, wherein a neodymium magnet is disposed on the cylinder at the tip of the torch, and a twist blade for imparting a turning force to the vaporizing flux is disposed on the cylinder.   The mixer includes a short pipe provided with the CO2 supply port, the mixed shield gas discharge port, and a venturi section. The short pipe communicates with a plurality of gas pipes, and Ar, He, and N2 are connected to the gas pipes. Supplying and mixing with the CO2 to generate the mixed shield gas, a mixing chamber is provided at the outlet of the short tube, a neodymium magnet is provided in the mixing chamber, and the mixing chamber is provided on the outlet side of the mixing chamber. The TIG welding method according to claim 1 or 2, wherein an oblique nozzle hole is provided in the flange and a neodymium magnet is provided in the discharge port in order to give rotation to the mixed shield gas.

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