Showing papers on "Shielding gas published in 1984"

Portable arc voltage wirefeed welding system

Abstract: A portable wirefeed and control apparatus for use in consumable electrode arc welding systems which is capable of being powered by conventional AC or DC variable voltage or variable current supplies without modification of the power supply or the wirefeed and control apparatus. The portable wirefeed unit incorporates a wirefeed motor, a supply of weld wire, optional gas controls, and voltage regulating and protective control circuits all powered at welding arc voltage carried by the welding current supply conductor. The unit is circuit connected to the power supply by means of a single welding electrode supply conductor and a ground return. Electrode power, weld wire, optional shielding gas supply and welding gun control switch conductors are carried in a single flexible conduit extending between the control unit and a remote welding gun and wirefeed speed and thus wirefeed rate are partially responsive to variations in welding arc voltage.

Output control of short circuit welding power source

Abstract: A method of controlling the output of a power source in consumable electrode arc welding in which a short circuiting phase and an arcing phase alternately take place between a consumable electrode and a workpiece in a shielding gas atmosphere, the method being characterized by repetition of a cycle of operation consisting of: a first stage of maintaining the output welding current at a first value of a relatively low level upon establishment of a short circuit across a gap between a consumable electrode and a workpiece; a second stage of maintaining the welding current at a second value of a relatively high level succeedingly to the first stage; a third stage of lowering the welding current to a third value of a low level upon detection of necking as a premonition of rupture of short circuiting molten metal between the electrode and workpiece; a fourth stage of, upon generation of an arc across a gap between the electrode and workpiece subsequent to the third stage, maintaining the welding current at a fourth value of a relatively high level exceeding the value of average welding current; and a fifth stage of maintaining the welding current at a fifth value of a relatively low level until the gap between the electrode and workpiece is short-circuited, under control of substantially constant current characteristics to feed current of constant level irrespective of variations in arc length.

Arc welding system and docking assembly therefor

Abstract: In a MIG arc welding system, a docking body having utilities passages therethrough is mountable at the welding station. Means are provided at one end of the body for accepting incoming utilities such as consumable wire electrode, shielding gas, welding potential and cooling water. Different types of welding gun or torch assemblies are interchangeably manually mountable and demountable at the other end of the welding body without disturbing the docking body or the utilities coupled thereto. Plug-type water fittings on the welding gun or torch assembly are receivable in receptacles in the docking body which communicate with the water passages, actuator tips on the fittings actuating normally-closed, spring-biased check valves in the passages to prevent leakage of water from the docking body when the welding gun or torch assembly is demounted. The gun or torch assembly is held in place by a coupling nut which is threadedly engaged with the docking body. There are provided a fixed-mount embodiment, wherein all utilities but the welding wire enter the docking body radially, and a remote or movable mount embodiment, suitable for mounting on a movable mechanized or robotic support, wherein all utilities enter the docking body axially. A positioning ring on the latter embodiment accurately positions the docking body on the movable support.

Tubular welding electrode

Abstract: A formulation for the flux in a cored-type electric arc welding electrode which produces high impact value welds while welding vertically up or overhead and at greater melt-off rates than heretofore. The major flux ingredients are lithium oxide, iron oxide, silicon dioxide, lithium carbonate, magnesium and aluminum metal powders, all in a carefully balanced formula to give excellent operator appeal and excellent slag removal.

Consumable electrode type arc welding method

Abstract: PURPOSE:To suppress the generation of defective shape beads such as welding defects lacking in fusion, etc., and drooping of beads in attitude welding by repreating alternately by an optional number of times each a short-circuit shift and a spray shift for controlling a heat input and controlling the bead shape. CONSTITUTION:Electric conduction is executed between a wire 31 and a material to be welded 35 from a welding power source 37 while supplying a shielding gas (g) from a feed port 32b, the wire 31 is melted by generating an arc (a) and dropped down onto a base metal 35, and a welding torch 32 is moved and the base metal is deposited by heating it and making molten pool (m). Its welding condition and a wire 31 feed speed are set by setting devices 40, 41, and an output of the power source 37 and rotation of a motor 46 are controlled by a controller 42 so as to reach said set condition. The welding condition is controlled by monitoring a welding current level, but a welding current and a current waveform being the origin of this control are obtained from an output of a welding current detector 38, for instance, short-circuit and pulse shifting periods Ta, Tb are as shown by waveforms in the figure. This waveform is processed by a device 39, and each shifting time T1, T2 is detected.

Method for preventing the discoloration of areas around indentation in spot welding

Abstract: A method for preventing discoloration of the area around an indentation in spot welding is provided in which the weld zone and its surrounding area are masked with a non-oxidizing gas such as argon gas, helium gas, nitrogen gas or a mixture of argon gas and carbon dioxide gas from ambient atmospheric air and spot welding is carried out in the atmosphere of the non-oxidizing gas to prevent the discoloration from occurring at the weld zone of a metal sheet under the influence of heat during spot welding.

Gas-metal-arc welding process

Abstract: In a gas-metal-arc welding process, a stable plasma formation is produced by a shielding gas mixture whose flow is focused to steadily maintain the plasma formation in central alignment with the arc. Thus, the plasma energy and arc energy are combined and concentrated to yield a higher, more stable welding heat. The process is of the type that utilizes a welding gun having a consumable wire electrode that is continuously advanced towards the weld deposit as its end melts and is transferred to the weld deposit. The gas is a mixture of major proportions of each of argon and helium and minor proportions of each of carbon dioxide and oxygen, which produces a stable, approximately dome-like plasma formation in the arc gap between the electrode melting end and the weld deposit. A portion of the gas that flows through the gun nozzle and around the electrode, is directed at an acute angle towards the electrode axis within the arc gap, and is focused, by adjusting the gap length, upon a spot on the electrode axis at the weld deposit, so that it impinges upon and pressures the plasma formation inwardly into axial alignment with the arc, producing an intense heat zone in the gap.

The Nitrogen Absorption of Stainless Steel Weld Metal by Gas Tungsten Arc Welding

Abstract: Using an arc atmosphere controlling chamber, effects of the welding conditions and atmosphere on the nitrogen content of the stainless steel weld metal by gas tungsten arc welding were investigated in comparison with those on the iron weld metal. The results are as follows:(1) The temperatures of stainless steel and iron molten pools were measured as about 1530°C and 1630°C, respectively.(2) The nitrogen content of stainless steel weld metal decreased with increasing the welding current, as well as that of iron weld metal.(3) The nitrogen content of stainless steel weld metal hardly depended on the arc length, as well as that of iron weld metal.(4) The nitrogen content of stainless steel weld metal increased with increasing the travel speed, while that of iron weld metal hardly depended on the travel speed.(5) The nitrogen content of stainless steel weld metal increased with the nitrogen partial pressure at low nitrogen partial pressure region, and was constant at the nitrogen partial pressure region above 0.2 atm in N2-Ar gas mixture atmosphere, as well as that of iron weld metal.(6) The nitrogen absorption by stainless steel weld metal was discussed with equilibrium data.

Rotary welding device

Abstract: A welding device for building up metal for repair or construction of a metal bores, outside diameters and circular faces by laying down single or continuous metal weld beads in a pre-selected pattern; including a base member to receive a rotatable table with a drive is provided on the base to rotate the table at selected speeds. An elongated tubular spindle is provided to rotate with the table. Conduits for welding wire, welding current (power) and a shielding gas supply is provided to the spindle to supply gas, power and wire to the area adjacent the point of exit of the wire. The tip of the spindle serves as one electrode contactor in a welding process and the metal to be welded serves as the other. The spindle rotates with movement of the rotating table where the table includes a horizontal guide member to receive a slide member which carries the spindle and the slide member is longitudinally moveable in the guide to be selectively advanced and retracted by a variable horizontal feed device also located on the rotating table and where the rotatable table further includes a rotatable threaded connecting member to receive the spindle where the outside of the spindle is threaded so that upon rotation of the connecting member the spindle is raised and lowered relative to the rotating table.

Consumable electrode type gas shielded arc welding method

Abstract: PURPOSE:To execute defectless and satisfactory welding with high efficiency by using a specific laser beam as a preceding heat source and defocusing specifically the spot diameter of a laser beam. CONSTITUTION:The CO2 laser beam or YAG laser beam 11 is used as the preceding heat source in the stage of executing consumable electrode type gas shielded arc welding. Said beam 11 is used after the spot diameter DY thereof is defocused to 2mm.<=DY<=25mm. and materials to be welded are subjected to MIG welding while said materials are uniformly heated over a wide range by the out-of-focus beam.

Gas shielding apparatus

Abstract: An apparatus for preventing oxidation by uniformly distributing inert shielding gas over the weld area of workpieces such as pipes being welded together. The apparatus comprises a chamber and a gas introduction element. The chamber has an annular top wall, an annular bottom wall, an inner side wall and an outer side wall connecting the top and bottom walls. One side wall is a screen and the other has a portion defining an orifice. The gas introduction element has a portion which encloses the orifice and can be one or more pipes. The gas introduction element is in fluid communication with the chamber and introduces inert shielding gas into the chamber. The inert gas leaves the chamber through the screen side wall and is dispersed evenly over the weld area.

Arc welding filter

Abstract: A device intended to remove pollutants from the gases surrounding an arc welding operation comprising principally a blower adapted to draw the gases away from the welding operation The gases are drawn into an inlet located near the work area through a hose having coils adapted to absorb heat from the gases A filter using both magnetic and mechanical means is used to filter the pollutants from the gases before discharging into the ambient atmosphere

Welding 304l stainless steel tubing having variable penetration characteristics

Abstract: Following difficulties with heat–to–heat variation in weld penetration enountered during GTA welding of stainless steel tubing, a program was undertaken to identify the cause of the problem and to develop remedial techniques. The variation in weld penetration was attributed primarily to differences in sulphur and, to a lesser extent, oxygen content, in broad agreement with a published model for such effects based on surface tension. The incorporation of copper alloy heat sinks into the standard welding head was successful in overcoming the problem. Both argon − 1% oxygen shielding gas and multipass welding procedures have been demonstrated to be promising alternative solutions, but these techniques have not been fully developed. To prevent the recurrence of the problem in future construction, a limit of 100–200 ppm sulphur has been included in the material specification for tubing purchases.

Hot wire tig welding method

Abstract: PURPOSE:To make a hot wire TIG arc welding highly efficient by varying periodically in the prescribed frequencies a mean arc current and by controlling the wire heating power source so as to become the heating electric power corresponding to the feeding speed by detecting the heating electric power of the wire. CONSTITUTION:TIG are welding is performed by outputting a pulse current Iap from a power source 4 with setting of a base current Iab on a power source 19 and by switching continuously in >=10Hz the output current of the power source 4 to an arc 5 and wire 6 by GTO14, 15. In this case a mean arc current Im is periodically varied in <=4Hz and the heating power of the wire 6 is detected by detector 18. The wire electric welding time TW is determined then so as to become the heating power corresponding to the feeding speed of the wire 6 and the power source 4 is controlled by a heating control device 16. The increase in the arc current during LOW period and wire melting rate is thus enabled and the high efficient TIG arc welding having good operability is realized.

Pulse arc welding

Abstract: PURPOSE:To perform stable welding that generates little spatter in consumable electrode type gas shielded arc welding by using an arc current pulse current consisting of main pulse current and sub-pulse current. CONSTITUTION:When a base metal to be welded 18 by generating an arc 17 between a consumable welding wire 16 in welding torch 15 and a base metal to be welded 16 under the presence of shielding gas, welding current is set to pulse current constituted of current values 6, 7, 8. In this case, current generating devices 3, 4, 5 are switched by a time 2 to be times 9, 10, 11, 12 to obtain pulse current having main pulse 13 and sub-pulse 14 of smaller current than the main pulse. A droplet is formed at the end of the welding wire by the main pulse current 13, and the droplet is separated from the tip of the wire 16 to a molten pool by the sub-pulse 14. Thus, stable consumable electrode type gas ghielded welding that generates little spatter can be performed.

Internal bore welding torch having removable flexible wand for remote welding

Abstract: An internal bore welding torch assembly and method for use in making remote arc welds inside metal tubes. The torch assembly includes a torch body unit of plastic electrical insulating material, to which is connected the necessary welding services of coolant, shield gas, and electric power. The body unit contains a removable and rotatable welding wand which is made of flexible plastic and has a welding electrode oriented radially at its outer end. For making a weld, such as for repairing a damaged tube, a metal sleeve is first inserted into the tube the flexible welding wand is then inserted into the tube and the radial electrode positioned adjacent an end of the sleeve. The flows of coolant and shield gas are provided through the torch body unit to the wand, and the wand is rotated while making the metal arc welds desired to seal weld the sleeve ends to the tube.

Narrow gap tig arc welding torch

Abstract: PURPOSE:To stabilize welding and prevent occurrence of defects by forming shield gas tubes of a ferromagnetic material and utilizing these shield gas tubes as ferromagnetic poles. CONSTITUTION:Shield gas tubes 5 and 6 arranged in front and rear of the direction of advance of welding and a torch fixing member 11 are formed of high magnetic permeability material, electromagnetic soft iron etc. Thus, a nearly horseshoe-shaped magnetic path is formed to hold a tungsten electrode 1 by the tips. Magnetic field across an arc forming part at tip of a torch is formed by flowing tributary exciting current to a coil 14 wound to a fixing member 11. Accordingly, an arc oscillates in the direction of gap width. Thus, allowable limit for fluctuation of gap width during narrow gap welding is widened and stable welding is made possible, and at the same time, occurrence of welding defects can be prevented.

Wire bonding method

Abstract: PURPOSE:To prevent a ball from oxidizing and to contrive to improve the bonding property of wire by a method wherein, when the ball is formed on the point of the wire, gas, wherein H2 gas has been mixed with inactive gas, such as N2 gas, at a ratio of 0.01-1.0vol%, is used as shielding gas for oxidation prevention, which is sprayed on the region embracing the point of the wire. CONSTITUTION:In case a wire 13 is bonded on the pad part of a pellet 17, firstly, the main body 14 of a torch is made to advance in such a way that a torch electrode 16 opposes to the lower end of a capillary 12. At this time, the point of the wire 13 inserted in the capillary 12 is made to approach the lower end of the capillary 12. On the other hand, shielding gas, which is fed from a shielding gas feed source, is blowing off from a feeding port body 14. Therefore, the region embracing the torch electrode 16 and the point of the wire 13 has been shielded from the atmosphere by the shielding gas. When voltage is impressed on the torch electrode 16 under this condition, sparks generate and a ball 18 is formed on the point of the wire 13. As a result, the surface oxidation of the ball 18 can be prevented, because the ball 18 has been covered with shielding gas, wherein H2 gas has been mixed with inactive gas at a ratio of 0.01-1.0vol%.

Metallurgical reaction and deposit fusion boundary microstructure under a stationary plasma arc

Abstract: Alloy element loss, decarburization in melted region and microstructural change of a deposit fusion boundary under a stationary plasma arc have been investigated by a first-order kinetic and interfacial microstructure. The cylindrical specimens of iron-based alloys, Fe-C, Ni-C, and Co-C alloys were locally melted by a plasma arc using argon plasma gas and Ar+H2 shielding gas, and the rates of alloy element loss and decarburization in the melted region were measured. Moreover, the fusion boundaries experienced when nickel, iron, Ni-Fe filler metals were deposited on iron, Fe-C, nickel and cobalt base metals, were evaluated metallographically. The initial rate of alloy element loss decreases as follows: Fe-Al>Fe-Mn>Fe-Cr>SGI-Mg>Fe-Ni. The loss reaction mechanism is metallic evaporation and the rate seems to be limited by transport in the gas boundary layer. The magnitude of decarburization is as follows: Ni-C>Fe-C> Co-C. The decarburization rate in Fe-C alloy is assumed to be governed by a process involving mass transfer in the gas phase and the molten metal. However, at low carbon concentrations, the rate appears to be limited by transfer in liquid metal. Fusion boundary deposited with nickel filler metal on iron is regular, but with carbon added to iron, an infiltration of deposit metal into adjacent base metal occurs. The fusion boundary with iron deposited on nickel is irregular where thin Ni-Fe solid solution is formed. In a deposited fusion boundary of cobalt with iron, nickel, and Ni-Fe filler metals, FeCo compound formation occurs, with cobalt dissolving into the nickel deposit metal resulting in a tongue-like structure produced by nickel penetration and a fine columnar substructure formation produced by Ni-Fe diffusion.

Welding method in tig welding

Abstract: PURPOSE:To make arc firing easy in TIG welding by using gas of a low electrolytic dissociation voltage in the stage of arc firing. CONSTITUTION:A control circuit 6 for a gas selector valve turns a valve 5 on when a start operation is made. Then gaseous argon arrives at a welding head 1 by passing a pipe 3 and is ejected as preflow of arc shielding gas. A voltage is applied between the electrode 1a in the head 1 and a base material 10 by a welding power source 7 in succession, whereby arc firing is accomplished. The welding current supplied from the power source 7 increases sharply upon completion of the arc firing. The increase in the current is detected by a current detection circuit 8 and the circuit 6 turns a solenoid valve 4 and a solenoid valve 5 off according to the selected pattern for the selection of the gas to change the kind of the gas from gaseous argon to gaseous helium. The gaseous helium is ejected as arc shielding gas from the head 1.

Cr-mo wire for mig welding

Abstract: PURPOSE:To obtain good low temp. toughness while suppressing temper embrittleness phenomenon and preventing generation of weld defects such as blowholes by specifying the composion component of a wire for MIG welding. CONSTITUTION:A Cr-Mo wire for MIG welding by using a gaseous mixture composed of Ar-O2, Ar-CO2, etc. as shielding gas is constituted by contg. essentially 0.04-0.10% C, 0.25-0.55% Si, 0.85-1.20% Mn, 2.00-3.50% Cr, 0.90-1.20% Mo, 0.040-0.100% Ti, 0.012-0.032% N, and 0.005-0.020% O, in which Mn/Si (by weight) is >=2.2 and 100N/Cr (by weight) is 0.5-1.4 and consisting of the balance iron and unavoidable impurities.

Sealing welding method

Abstract: PURPOSE:To obtain a good sealing bead by placing a shielding gas welding torch and a submerged arc welding torch on one self-traveling carriage by placing the former in precedence to the latter and performing sealing welding by the intermission of welding current. CONSTITUTION:A selaing gas welding torch 7 and a submerged arc welding torch 2 are placed on one traveling carriage 1 by placing the former in precedence to the latter and the carriage 1 is advanced in an arrow 12 direction. Shielding gas welding is performed by the intermitted welding current while a welding wire 9 is detected with a detecting sensor 8 by a control box 11 contg. timers and switches for the purpose of intermitting the shielding gas welding current in addition to those for adjusting submerged arc welding conditions. The flux in a flux tank 3 is then sprayed from a spray nozzle 4 and the submerged arc welding is performed. The flux is recovered with a recovering nozzle 5.

Welding conduit stop

Abstract: A welding gun apparatus to supply welding wire, electrical power, and shielding gas to a working area includes a connector plug with a conduit stop therein. The conduit stop is fittedly received within a bore in the connector plug and is of unitary one-piece construction so as to provide a fluid-tight fit therewith.

Turning device for welder

Abstract: PURPOSE:To execute welding by turning a welding head, by turning a turning part to which the welding head has been attached, by using the center of a nozzle as the turning center, and providing a rotary connecting part of a cable, etc. on a fixed part. CONSTITUTION:When a claw 22 of a chuck part C is pressed vertically against the inside surface of a nozzle of a member to be welded, a turning device can be held concentrically with the nozzle. Subsequently, welding is executed by positioning a welding head attached to a fitting plate 2 of a turning part A, in a groove, and rotating a turning table 1. Electric power, cooling water and a shield gas, etc. which are required for this welding are supplied through a power cable 30, a control cable 40, a cooling water hose 50 and a shield gas hose 60, respectively. The cable, etc. are not twisted due to a feed part D1 of a rotary connecting part D, an electric conduction part D2, and a feed water (gas) part D3, and do not become an obstacle to turning of the welding head.

Tig welding method

Abstract: PURPOSE:To form a smooth or projecting URANAMI irrespective of a welding position by mixing gaseous oxygen gas or gaseous carbon dioxide of a prescribed quantity into inert gas such as argon, etc, filling it as back shielding gas in a steel pipe, and executing URANAMI welding CONSTITUTION:Gaseous oxygen of about 2-10% volume ratio or gaseous carbon dioxide of about 50-80% volume ratio is mixed in gaseous argon, it is filled as back shielding gas in a stainless steel pipe, and URANAMI welding is executed at all position basing on a prescribed welding condition As a result, a smooth or projecting URANAMI bead is formed irrespective of a welding position, and a projecting amount of the projecting shape becomes about 030mm in the maximum In this way, even in case of an overhead position in which it is the most difficult to control the URANAMI bead, a recess of the URANAMI bead can be eliminated completely

Cementing method of steel

Abstract: PURPOSE:To apply cementation treatment to the necessary part of a steel material in a short time, by melting the aimed part of the steel material surface by plasma torch, and supplying a graphite or carbon compound in powdery state to the molten part. CONSTITUTION:The plasma torch 1 is opposed to the steel material 11 to be cementation treated, DC voltage is impressed between the material 11 and an electrode 7 made of W of the torch 1, shielding gas and working gas are supplied from a shielding gas passage 4 and a working gas passage 5 respectively. The working gas is made plasmatic by the discharge between the electrode 7 and the plate 11, a plasma arc 12 of high temp. and high speed is jetted from a jetting hole 8, and a molten part 13 is formed on the plate 11. Simultaneously, <=50mu graphite powder whose surface is plated with Cu or Ni, or a powder 14 of carbide such as Si, Cr, Mo is blown to the arc 12 from a powder introducing tube 10. Hard cemented layer having high carbon content can be formed at the part 13 in a short time.

Gas shielded arc welding device

Abstract: PURPOSE:To weld satisfactorily the lower part of metallic members without blowholes by providing a gas feeder for ejecting shielding gas toward the lower part of the weld zone of the metallic members. CONSTITUTION:A feed tip 4 is inserted to near the lower part 8a of a hood 8 between round steel bars 1 opposed to each other at a suitable spacing, and shielding gases are supplied from gas nozzles 10 and 11 into the hood 8. The entire part in the weld zone of the materials 1 is then welded while the tip 4 is oscillated and gradually moved upward. A gaseous curtain is formed in an opening 9 by the shielding gas supplied from the nozzle 11 during welding and therefore the inflow of gas such as air into the hood 8 from the outside of the hood 8 is obviated.

Tig welding method

Abstract: PURPOSE:To make a back shielding gas unnecessary, and to cut down expenses by using a wire containing a flux whose main component is CaF2, constituting so that the atmosphere contact surface of a bead is covered with a slag in a melted state, and executing a penetration bead welding. CONSTITUTION:In a TIG welding method, a wire 1 filled with a flux 3 containing CaF2 as a main component, and a small quantity of Al, Ti, Nb, Cr, etc. is used for a hollow part of a cylindrical hoop 2. When this wire 1 is used and a penetration bead welding is executed by a TIG welding method, the flux 3 of the wire 1 is melted together with the hoop 2 by an arc, and in its melted state, the atmosphere contact surface of a penetration bead is covered with a slag 5, and oxidation of the penetration bead 4 is prevented. The slag 5 is stripped off from the penetration bead 4 by giving a shock by a suitable means after the penetration bead welding is ended.