Showing papers on "Shielding gas published in 1988"

Apparatus and process for producing high density thermal spray coatings

Abstract: An attachment for supersonic thermal spray equipment by which inert shield gas is directed radially outwardly about the central core of a supersonic, particle-carrying flame to isolate the same from ambient atmosphere. The shield gas is injected tangentially against the inner surface of a constraining tube attached to and extending from the discharge end of the thermal spray gun nozzle, causing the shield gas to assume a helical flow path which persists until after it exits the tube and impacts the work piece. A process using the shielding apparatus with a high-velocity, thermal spray gun and employing oxygen and hydrogen as gases of combustion and inert gas to introduce metal powder, having a narrow particle size distribution and low oxygen content, into the high-velocity combustion gases, produces significantly improved, high-density, low-oxide metal coatings on a substrate.

Welding parameters and the grain structure of weld metal — A thermodynamic consideration

Abstract: The grain structure of the weld metal can significantly affect its resistance to solidification cracking during welding and its mechanical properties after welding. An experimental study was conducted to investigate the effect of two basic welding parameters,i.e., the heat input and the welding speed, on the grain structure of aluminum-alloy welds. Gas-tungsten arc welding was performed under various heat inputs and welding speeds, with thermal measurements in the weld pool being carried out during welding and the amounts and nuclei of equiaxed grains in the resultant welds being examined using optical and electron microscopy. The experimentally measuredG/R ratios and the clearly revealed heterogeneous nuclei together demonstrated the thermodynamic effect of the heat input and welding speed on the weld metal grain structure.

Laser cutting and welding of sheet metal using a shield of compressed air

Abstract: A method of simultaneously cutting and welding metal, especially relatively thin sheets of metal, utilizing laser energy. The invention uses surface tension in the globule created at the site of the impingement of the laser beam on the work to form finished edges on both sides of the line of cut. A laser beam surrounded by a gaseous shield is used, the gas removing some of the molten metal but leaving sufficient to form the beads which comprise the finished edges on both sides of the cut. Using compressed air, as compared to an inert gas such as helium or argon, as the shield gas produces a significant cost savings at the "price" of some reduction in quality due to oxidation.

Constant arc voltage gas metal arc welding process

Abstract: A gas metal arc welding process employing a shielding gas mixture consisting essentially of (A) 2 to 12 volume percent carbon dioxide, (B) 20 to 45 volume percent helium and (C) the balance argon.

Gas tungsten arc welding machine with infinite rotating welding head and torch tilt

Abstract: This invention relates to a machine for practicing the gas tungsten arc welding process which includes means (5) for rotating the welding torch (28) continuously while welding. Means are provided for feeding the shielding gases, feed wire and electric current to the rotating torch while welding. Means (23) and (24) are also provided for tilting the torch about the point of welding. This invention makes it possible to weld continuously along a spiral path about a cylindrical object or on a flat or irregular surface.

Trailer shield assembly for a welding torch

Abstract: A trailer shield assembly (10) having a housing (24) with an open lower side and a welding torch (12) mounted so that a welding tip portion (48) of the torch (12) extends through the lower side of the housing (24). A flexible gas guide (76) is affixed to a rear wall (74) of the housing (24) and has an interior (116) in communicating relation with a welding region (34) of the housing (24). A flexible shield gas manifold (90) having a plurality of spaced openings (92) therein is disposed in an upper region (110) of the gas guide (76) and is connectible to a source (11) of shield gas. A diffuser (112) surrounds the flexible manifold and serves to distribute shield gas in an even layer downwardly to cover a hot weld. A pair of openings (96) in the flexible manifold (90) communicates with a second gas manifold (32) disposed in an upper region of the housing (24), with this second gas manifold (32) being provided with an aluminum gas diffuser (30). Diffuser (30) distributes shield gas ahead of torch (12) to cover metal preheated by this welding operation.

High rate deposition gas-metal-arc welding process

Abstract: A gas-metal-arc welding process, utilizing a four-gas mixture and relatively high voltage, produces a high rate of weld metal deposition. The process involves continuously advancing the end of a meltable, thin wire electrode towards a weld metal deposit surface, while maintaining a predetermined length arc gap therebetween. A flow of shielding gas, which is formed of major proportions of argon and helium and minor proportions of carbon dioxide and oxygen, coaxially surrounds and flows along the electrode end portion and arc gap towards the deposit surface. A relatively high electrical voltage and current density are applied to the electrode. A roughly conically-shaped, hot plasma field is formed within the arc gap between the electrode end and the metal deposit surface. The length of the arc gap and the voltage are adjusted to provide a plasma field base diameter which corresponds to and substantially overlaps the width of the weld bead and the narrow band of the metal deposit surface upon which the weld bead is deposited. Drops melted from the electrode are deposited by globular, free-flight transfer across the arc gap upon the deposit surface substantially within the field base diameter. To form the elongated, narrow weld bead, the electrode, with its concentric arc gap band plasma field, is moved sideways in parallel alignment with the axis of the weld bead. Thus, the process may be used for high deposition rate welding within relatively deep, narrow gaps, as well as upon more exposed metal deposit surfaces.

Consumable electrode gas shielded ac arc welding method and device

Abstract: PURPOSE: To stably maintain an arc in a wide range of welding conditions by feeding a consumable electrode at the speed corresponding to an output current and determining frequency in accordance with the feed speed and setting a weld time and a current in accordance with consumable electrode conditions. CONSTITUTION: The consumable electrode is fed at the speed corresponding to a set value of the output current via a wire feed speed setting circuit S1 and the frequency in accordance with the wire feed speed is determined by an output voltage frequency signal generation circuit FG. Further, the welding time and a reversed polarity current with a current value in accordance with conditions such as the consumable electrode material and diameter and a shielding gas component are set via a reversed polarity current signal generation circuit IRG and a period signal generation circuit TRG. By this method, the arc can be stably maintained in the wide range of the welding conditions. COPYRIGHT: (C)1989,JPO&Japio

Pressurized weld chamber

Abstract: A novel weld chamber and process for using such weld chamber are disclosed. A flow of shielding gas through the weld chamber is regulated to provide a constant pressure in the weld chamber while the shielding gas flow sweeps away metal vapors.

Plasma mig welding equipment

Abstract: PURPOSE:To stabilize a MIG arc by combining plasma welding equipment with MIG welding equipment and allowing to contain a MIG electrode in a plasma electrode to envelop the MIG arc in a plasma arc CONSTITUTION:The plasma electrode 37 of the plasma welding equipment 33 is hollow-shaped and the MIG electrode 43 is arranged coaxially therein via an insulating cylinder 49 Plasma gas 51 is supplied to the inside of this insulating cylinder 49 Furthermore, a chip 39 is arranged to the outside of the electrode 37 via an insulating cylinder 53 Said chip 39 is provided so as to cover the whole electrode 3 The outside of the chip 39 is surrounded by an external cylinder 55 and shielding gas 57 is supplied between the external cylinder 55 and the chip 39 A plasma power source 41 impresses the positive voltage on the electrode 37 and impresses the negative voltage on the chip 39 via a switch 59 and also impresses the negative voltage on base metal 60 A MIG power source 47 is connected with the MIG electrode 43 and the base metal 60 and impresses the positive voltage on a MIG wire 45 via the MIG electrode 43 and furthermore, impresses the negative voltage on the base metal 60 The MIG arc 65 is generated in the plasma arc 61 and maintained in a state being enveloped by the plasma arc 61

Production of tubular body

Abstract: PURPOSE:To obtain a tubular body in a manifold shape excellent in heat resis tance and by no means inferior in strength besides being made in light weight by superposing two press-formed plates and after joining the outer peripheral part thereof by laser beam welding and cutting the end face with a tube expand ed by bulging. CONSTITUTION:Plates 1a, 1b having 2 pieces of the upper and lower manifold like parts 2a, 2b are subjected to press forming. The upper and lower two plates 1a, 1b are superposed and the outer peripheral part of the mating face 3 thereof is joined by laser beam welding. CO2 laser beam using an argon gas as a shielding gas is used. A tube expanding is then executed in the specified shape of a manifold by bulging. A manifold 1 is obtd. by providing an opening part by cutting both end faces finally. The working method having a high productivity besides excellent performance and excellent in profitability is thus obtd.

Electrode carrying wire for GTAW welding

Abstract: A welding torch for gas tungsten arc welding apparatus has a hollow tungsten electrode including a ceramic liner and forms the filler metal wire guide. The wire is fed through the tungsten electrode thereby reducing the size of the torch to eliminate clearance problems which exist with external wire guides. Since the wire is pre-heated from the tungsten more wire may be fed into the weld puddle, and the wire will not oxidize because it is always within the shielding gas.

Fusion welding method for resin laminated metal plates

Abstract: PURPOSE:To improve quality of a weld bead by performing high energy density welding and passing through members to be joined and subjecting these to fusion joining and further, controlling the width of a molten pool to dimensions of specific times as much as the total plate thickness. CONSTITUTION:At the time of lap-welding resin laminated metal plates 1 and 2, the high energy density welding such as the plasma welding method is performed. In this case, a concentrated plasma arc 4 passes through the metal plates 1 and 2 and the molten pool 6 reaches the rear of the plate 2 and the weld bead 7 is obtained. At this time, the width W of the molten pool 6 is measured and the concentrating rate of the plasma arc 4 is controlled so that its value becomes less than five times as much as the total plate thickness (t) of the plates 1 and 2. Decomposed gas of a resin layer 13 is discharged by shielding gas from the end face of the plate 1 and gas of a resin layer 23 is also discharged by the arc 4. By this method, since discharging efficiency of the decomposed gas is improved and the occurrence of weld defects is prevented, the quality of the bead 7 is improved.

Composite welding method using tig and laser beam

Abstract: PURPOSE:To maximize penetration and to improve quality of a weld zone by limiting dimensions of an inside dia. and an outside dia. of a laser beam emission hole of a laser beam nozzle and the distance between the nozzle center and the TIG electrode tip. CONSTITUTION:In welding steels by using a laser beam and TIG jointly, the inside dia. D1 and the outside D0 of the laser beam emission hole of the laser beam nozzle 1 are made to 4mm-8mm and >=15mm respectively. Further, the distance (l) between the center of the laser beam nozzle 1 and the electrode tip of a TIG torch 2 is made to 2mm-5mm. Moreover, in addition to these conditions, flow rate of TIG shielding gas (fs) is made to 5l/min-20l/min to perform welding.

TIG and related processes

Abstract: The third volume in the series discusses Tungsten Inert Gas (TIG) welding and related advanced processes, including plasma arc welding and laser welding technology. Following an introduction to TIG welding and its characteristics when applied to a range of ferrous and non-ferrous metals, the author discusses the properties of shielding gases and their importance for this process. Material on laser welding and other newer techniques leads into a discussion of commonly experienced defects and strategies for their elimination.

酸化物入りタングステン電極の消耗変形,rim形成について ガス・タングステン・アーク電極の研究(2)

Abstract: A comparative study has been made of characteristics of Gas-Tungsten-Arc cathodes, consisting of tungsten mixed with a small quantity of lanthanum, yttrium, cerium, thorium oxides respectively. Through observation of oxide contained in electrode after arcing, the change in electrode properties are discussed. The oxide changes its shape and distribution during arcing by the melting of oxide itself, and consequently disappears from the surface layer, which is the reason why arc starting loses the normal behavior. The introducing oxygen into shielding gas promotes intensely the electrode consumption and resulted in forming the "rim" at the periphery just behind the cathode area. It gives serious problems in durability of electrode and the stability of arc.

Internal wire guide for GTAW welding

Abstract: A welding torch for gas tungsten arc welding apparatus has a filler metal wire guide positioned within the torch, and within the shielding gas nozzle. The wire guide is adjacent the tungsten electrode and has a ceramic liner through which the wire is fed. This reduces the size of the torch and eliminates the outside clearance problems that exist with external wire guides. Additionally, since the wire is always within the shielding gas, oxidizing of the wire is eliminated.

Estimation of contact tip-workpiece distance in gas shielded metal arc welding

Abstract: (1988). Estimation of contact tip-workpiece distance in gas shielded metal arc welding. Welding International: Vol. 2, No. 6, pp. 522-528.

Horizontal narrow groove welding method

Abstract: PURPOSE:To facilitate monitoring an arc and adjusting the objective position of a wire by making the tip of a shielding gas nozzle flat in the direction of a weld line to insert it into a groove and adjusting properly the projectional length of a contact chip in accordance with an increase of the number of welding layers to perform the welding. CONSTITUTION:The tip part of the shielding gas nozzle 11 is made flat in the direction of the weld line. This flat part 11A is provided to a nozzle main body 11 via a slant part 11B and the short inside diameter is made to an ellipse somewhat larger than the outside diameter of the contact chip 2. The flat part 11A can be inserted into the horizontal narrow groove G by adjusting the projectional length of the contact chip 2 and shielding gas such as Ar+CO2, etc., can be certainly extended up to the inner part of the groove G. Further, the windproofness is improved by the wide shielding gas flow at both sides of the wire 1 in the direction of the weld line and further, since the tip of the nozzle is flat, the monitoring of the arc and the adjustment of the objective position of the wire can be easily carried out.

Hydrogen induced cracking in cold worked AISI 4140 steel welds

Abstract: The relative susceptibility to hydrogen induced cracking of cold deformed AISI 4140 steel welds was investigated. Controlled amounts of diffusible hydrogen were introduced into these weldments by utilizing the gas metal arc welding process with additions of hydrogen to the shielding gas. The crack behaviour was measured in terms of total crack length and distance from the fusion line. The crack propagated along the coarse grain structure of the HAZ about the fusion line. The refinement of the grain resulting from the increased cold roll reduces the crack activity. The susceptibility to hydrogen induced cracking of the cold worked samples appear to be sensitive to a critical value of residual stresses and to the orientation of the weld with respect to the rolling direction.

Manufacture of welded steel pipe

Abstract: PURPOSE:To realize the welding to manufacture a steel pipe with high efficiency and high quality by performing high-frequency heating on both edge parts of a formed pipe and forming molten metal by a buried arc while supplying a gas shielding type consumable electrode to a gap part to upset both the edge parts in a molten state. CONSTITUTION:A band plate roll-formed in an open pipe state is passed through an induction coil 3 and both the edge parts 1a and 1a of the open pipe are heated to >=800 deg.C and below the molten temperature by a high-frequency current. Next, the buried arc 8 is ignited in an atmosphere of shielding gas 7 while supplying the reversed polarity consumable electrode 6 to the gap part 1b of the edge parts 1a and 1a and end face surface layer parts 1c and 1c of the edge parts are molten to form the molten metal 4. Continuously, the upset quantity >=1/5 of the thickness T of the band plate is added to the edge parts 1a and 1a to obtain a butt welded zone 10. By this method, the welded steel pipe having the same soundness of the welded zone as the arc welding at the same welding speed as the resistance welding can be manufactured.

Copper strap for welding deformed bar steel and semiautomatic enclosed welding method

Abstract: PURPOSE: To prevent the occurrence of weld defects such as a blowhole and incomplete fusion by using an upper copper strap provided with a groove for supplying gas and a bead formation auxiliary groove on the inside and having a welding port and a lower copper strap having a bead formation auxiliary groove on the inside. CONSTITUTION: The title copper strap is formed of a couple of copper straps of the upper copper strap 3 and the lower copper strap 2 having a semicylindrical shape respectively. The upper copper strap 3 is provided with the groove 11 for supplying gas and the bead formation auxiliary groove 12 on its inside and has the welding port 13. The lower copper strap 2 is provided with the bead formation auxiliary groove 12' on its inside. At the time of welding work, since the groove for supplying gas to shield a groove part is not a hole, it is not blocked up with spatters and weld metal and an accident such as stoppage of the supply of the shielding gas hardly takes place. In addition, removing work of attached matters such as the spatters is also easily carried out. Accordingly, the shielding of a weld zone is always perfectly maintained and the occurrence of the blowhole can be prevented. COPYRIGHT: (C)1989,JPO&Japio

Method for repair welding of defective piping

Abstract: PURPOSE: To execute repair welding by generating an arc, while suppressing bleeding of an internal fluid by using a hollow electrode for a W electrode held by a TIG welding torch, feeding a welding wire from an inner cavity of the hollow electrode, and simultaneously allowing shielding gas to flow. CONSTITUTION: At the time of repairing a piping in which a fluid is contained, a hollow W electrode 9 and a welding wire 10 protruded from its tip are allowed to confront a defective part 13, and an arc 15 is generated between both of them. Subsequently, a temperature of water or vapor 14 in a piping 12 rises and the water or vapor is going to bleed out through the defective part, but shielding gas is allowed to flow intermittently from an inner cavity of the hollow W electrode 9, and the water or vapor is pushed in the direction as indicated with an arrow into the piping 12. The arc 15 and a molten pool which is formed are stabilized the welding wire 10 is supplied automatically thereto and a sound weld bead 16 is formed. In such a way, while suppressing bleeding an internal fluid from the defective part of the piping, sound repair welding can be performed. COPYRIGHT: (C)1990,JPO&Japio

Effect of nitrogen on weld metal toughness in self-shielded flux-cored arc welding

Abstract: Self-shielded flux-cored welds were made with varying electrode extension to investigate the effects of atmospheric nitrogen on mechanical properties. It was concluded that formation of aluminium nitrides seriously degrades weld metal toughness at long electrode extensions.

Welding method for galvanized steel sheet

Abstract: PURPOSE:To reduce welding defects and to weld galvanized steel sheets to an excellent shape by making a steel wire to perform the gas shielding arc welding of the galvanized steel sheets in the range of a specific component and also, making the composition of shielding gas to a specific percentage of content of CO2 to generate a stable arc. CONSTITUTION:The component of the steel wire to perform the gas shielding arc welding of the galvanized steel sheets is made as follows. The component of C is made to <=0.15% to enhance the toughness of the steel wire. The components of Si and Mn are made to 0.3-1.0% and 0.7-1.8% respectively and the occurrence of a blowhole due to a deoxidation shortage is prevented and the components of Si and Mn and made in the range not to make a bead shape defective. The component of Ti is made to 0.005-0.60% to form a bead with the excellent shape with a few pits. The components of P and S are made to <=0.02% and <=0.03%, desiably 0.015-0.03% respectively to prevent a weld crack. Furthermore, the composition of the shielding gas is made to Ar + (3-18)% CO2 to reduce the blowhole or a spatter and the pit. If the welding is performed under the above-mentioned condition, a weld zone with the excellent bead shape with a few defects can be obtained even if a Zn layer is not removed.

Gas shielded arc welding method for hydrogen inductive cracking resistant steel

Abstract: PURPOSE:To perform the titled gas shielded arc welding by using hydrogen inductive cracking resistant steel containing specific elements as hydrogen inductive cracking inhibitive components in the quantities to attain a specific value with a parameter value in accordance with a formula as base metals to be welded. CONSTITUTION:The hydrogen inductive cracking resistant steel containing the rare-earth element and/or Ca as the hydrogen inductive cracking inhibitive components in the quantities to attaint >=0.10 with the parameter A value in accordance with the formula corresponding to those component quantities is used as the base metals to be welded. Then, a welding wire containing <=0.08wt.% Ti with the DC reversed polarity of a welding current 230-50A is used to perform the gas shielded welding. In this case, a short-circuit shift region arc stabilization means to use mixed gas of inert gas with carbonic acid gas to store 20vol.% at least therein as shielding gas is applied. It is provided that in the formula, [ ]denotes the component content (wt.%).

Method for welding super heat resistant material and the like

Abstract: PURPOSE:To automatically weld a super heat resistant material, etc., and to improve a quality and welding efficiency by welding a welding material with feeding it in the weld line direction in a powder state. CONSTITUTION:A cooling water is fed via a cooling water circulating device 12 and piping 11 to a welding torch 1 and a shielding gas is fed via a gas pie 8 and gas passage 9 from a gas bomb 10. And a shielding gas atmosphere 7 is formed, the gas of the gas bomb 10 is fed to the welding torch 1 via a powder feeding device 16 from a gas pipe 15 and the state of continuously feeding the welding material powder 13 in the necessary amt. is made. A welding current is then fed to a tungsten electrode 2 via a cable 3 from a welding power source 4. A plasma arc 6 is then formed between the tungsten electrode 2 and base metal 5, the powder 13 is easily melted under shielding gas atmosphere 7 and a molten pool 21 is formed. When the welding torch 1 is traveled in weld line direction, then, continuous automatic welding can be executed.

Torch for wire bonding device

Abstract: PURPOSE:To prevent oxidization of a ball by accurately shielding the region of a torch electrode and the tip of a wire from the atmospheric air, and to maintain the ball at a high temperature by a method wherein a feeding member of shielding gas is integrally provided on the torch main body to be used for a sparking, and a heater to be used for heating up shielding gas is provided in a feeding member hole. CONSTITUTION:On the torch to be used for the wire bonding device with which a ball 24 is formed at the tip of the wire penetrating a capillary 12, a torch main body 14 with which a ball 24 is formed at the tip of the wire 13 by generating a spark between the wires 13, a gas feeding member hole 16 which is connected to said torch main body and with which the ball 24 formed at the tip part of the wire 13 is isolated from the atmospheric air by jetting shielding gas, and a heater 21 which is formed in the gas feeding member hole 16 and used to heat up the shielding gas, are provided. For example, the end part of the shielding gas feeding member hole 16 is connected to the cylinders of the inert gas such as nitrogen gas, argon gas and the like or hydrogen mixed gas through the intermediary of a gas tube 18. Also, a rod type electric heater 21 is provided in the gas feeding member hole 16, and the heater is connected to a heater power source 22.