Showing papers on "Gas metal arc welding published in 1986"

Method for repairing a steam turbine or generator rotor

Abstract: This is a method for repairing low alloy steel steam turbine (both high pressure and low pressure sections) or generator rotors. The defective section of the original rotor is removed and a replacement end is used, with mating attachments machined on the replacement end and the original rotor. The inner portion of the weld joining the replacement end to the original rotor is provided by a narrow gap weld, either by gas metal or by submerged arc welding. The outer 1/2-2 inches of the weld is provided by gas tungsten arc welding. The mating attachment and at least the inside 1/4 inch of the weld is bored out to remove possible crack initiation sites and to provide a smooth inspectable bore. In this manner, a fast and reliable technique is provided which provides accurate alignment, fast, essentially distortion free welding, and the superior mechanical properties of gas tungsten arc welding in the outer, more highly stressed zones.

Metal vapors in gas tungsten arcs: part ii. theoretical calculations of transport properties

Abstract: Theoretical calculations of gas tungsten arc transport properties have revealed that small amounts of low ionization potential elements such as aluminum or calcium do not have as great an effect on the electrical and thermal conductivities as has been previously reported, if the presence of other metal vapors such as iron or manganese is also considered. It is therefore concluded that the effects of minor elements on arc properties may be less important than has previously been believed in explaining the variable penetration often associated with minor element additions to the base metal, and that weld pool convection effects such as surface tension modifications are probably more important. However, the effects of vapors emitted by the tungsten electrode may have a great effect on arc properties, as the shielding gas is otherwise free of contaminants in the upper regions of the arc.

Control for gas metal arc welding system

Abstract: An arc welder control in which the current is pulsed between a high level and a low level. The high level pulse is maintained until a selected energy condition is satisfied. The low level pulse is maintained to satisfy an average energy condition. A proximity control moves the torch head and the feed wire tip toward and away from the work to stabilize a parameter of welder operation which may deviate with the current pulse energy control.

Gun and cable for gas metal arc welding

Abstract: An electrode gun and cable for feeding a welding electrode and shielding gas to a workpiece having an improved arrangement for supplying the gas to the arc and for electrifying the electrode in the contact tip. The cable is designed to resist abuse and purge air entering with the electrode. The gun nozzle has a square passage to receive the electrode guide and provide unobstructed gas passages. The trigger has a flexible member engaging the on-off switch to prevent damage thereto from too much pressure by the operator.

Semi-automatic hot wire tig welding equipment

Abstract: A semi-automatic hot wier TIG (Tungsten Inert Gas) welding equipment comprising: a portable TIG arc torch; a portable filler wire feed torch; a hot wire switching power source for energizing the TIG arc torch, the filler wire feed torch and a base metal; a filler wire feeding device for feeding the wire to the wire feeding torch at a desired rate; a welding condition control device for controlling wire heating power so as to provide wire heating power commensurate to the wire feed rate; means for measuring the resistance value of the wire extension section between the terminal end of the wire and the terminal end of the filler wire feed torch; and means for controlling said filler wire feeding means to change the wire feed rate in response to the detected wire extension According to the present invention, the welding operations are performed while the filler wire feed torch is held in one hand and the TIG arc torch is held in the other hand, so that the position where the arc and wire are inserted can be desireably adjusted Adjustment of the welding conditions such as regulation of the welding arc current and adjustment of wire feed rate can be readily performed during welding

Gas shielded, flux cored, welding electrode

Abstract: A flux cored welding electrode for use in electric arc welding with a shielded gas, which electrode includes a tube of low carbon steel having on the inside thereof a titanium dioxide based flux with fluxing ingredients including aluminum oxide in the amount of 0.1 to 0.5% of the total weight of the electrode. The improvement of the invention wherein the titanium dioxide based flux with aluminum oxide free of magnesium or compounds of magnesium.

CO/sub 2/ laser beam weldability of Zircaloy 2

Abstract: BWR (boiling water reactor) fuel rods are manufactured by stacking pellets into a zirconium alloy, cladding tube-zircaloy 2(Zr2). A fuel rod is designed as a pressure vessel in order to prevent failure of the cladding and release of radioactive fission products. As a result, there are very strict requirements from the welding methods employed. The usual welding methods for Zr2 are based on the tungsten inert gas (GTAW) resistance welding (RW) and electron beam welding (EBW) processes. There is very little information about laser beam welding (LBW) of Zr2. The recent development of multikilowatt laser systems has led to dramatic improvements in their welding performance. In the present work, laser beam welding of Zr2 was investigated. A comparison with GTA welding was carried out. The use of a high-power laser beam to weld nuclear fuel containers made of zircaloy has many advantages: (1) The high-power density of the focused laser beam enables very high welding speeds in comparison with arc welding. As a result, a narrow heat-affected zone is produced and the distortion of the parts is reduced to a minimum. (2) The beam can be transmitted to different stations alternatively, even to ones located far from one another. Itmore » also transmits to hot cells, glove boxes or any inert gas pressure chamber through suitable windows. (3) The process can easily be automated to enhance mass production. It is very simple, does not require skilled welders, and does not need the use of different electrodes, collets, etc. (4) The laser beam does not contaminate the weld metal with tungsten or other elements.« less

Torch for preheating a continuously fed welding wire

Abstract: A torch for use in welding has a first embodiment for gas metal arc welding and a second embodiment used for hot wire gas-tungsten arc welding. Both embodiments include a torch housing having a first and second end. A wire guide tube is centrally disposed within the housing. An upper electrode contact tip, a lower electrode contact tip and a dielectric material disposed therebetween are positioned at one end of the wire guide tube. An inner power cooling assembly comprises a first cylindrical member concentrically disposed about the wire guide tube and provides electric power to the upper electrode contact tip. The inner power cooling assembly defines a first chamber within which cooling water is circulated in contact with the upper electrode contact tip. An outer power cooling assemblycomprises a second cylindrical member and is electrically isolating from the inner power assembly. The second cylindrical member is in electrical communication with the lower electrode contact tip and defines therewithin a second chamber within which cooling water is circulated. In the gas metal arc welding configuration, a gas supply assembly is included in the torch housing and comprises an outer gas tube circumferentially disposed about the second cylindrical member.

Baked flux for submerged arc welding

Abstract: A baked flux of high basicity for submerged arc welding which has a chemical composition suitable for use in universal combination with various types of welding wires in welding low alloying steels. The baked flux reduces the oxygen content and diffusible hydrogen content of the weld metal to form a weld metal having a high toughness, enables forming regular beads without causing weld defects such as lack of fusion and slag inclusion, and facilitates welding work. The performance of baked fluxes is described in comparison with that of the conventional baked fluxes.

Heat transfer in gas tungsten arc welding

Abstract: The heat transferred from an electrode negative, argon gas tungsten arc to an anode has been measured for a wide range of conditions suitable for mechanized welding applications The results are given as (1) the arc efficiency; and (2) the anode heat and current input distribution functional shapes and radii for various anode materials and groove shapes over a wide range of current and voltage, using different electrode geometries, as well as both He and Ar-He shielding gases The nominal arc is Gaussian with a diameter of about 4 mm and a heat transfer efficiency to the anode of about 75% Variations from these values are discussed in terms of current knowledge of the electrical and thermal energy transport mechanisms A new method of measuring the heat transferred from the arc to the anode, using a boiling liquid nitrogen calorimeter, has been developed which gives rapid, accurate values

Method for overlap welding clad steels by means of an energy beam

Abstract: Welding of clad steels using laser emission. Method for overlap welding at least two clad-steel plates using a laser-emission energy beam and in which a molten weld crater is formed in the metal, the said plates being held applied against each other, characterised in that it consists in leaving a gap 6 between the contact faces of the plates 1-2.

Gas-shielded arc welding apparatus

Abstract: A gas-shielded arc welding apparatus automatically welds materials to be welded, such as rails or shape steel. The apparatus includes a gas-shielded chamber and a pair of side backing plates arranged within the chamber whereby the whole weld zone of the materials is gas shielded and a welding nozzle and shielding gas outlets are separated from each other. The apparatus also includes a welding apparatus proper and a control unit thereby performing the welding in a fully automatic manner.

Influence of process variables in flux cored arc welding of hardfacing deposits

Abstract: A lack of knowledge and objective data on the effects of welding process variables in the application and performance of weld deposited hardfacings has led to many past failures and a subsequent mistrust of the technology. This paper sets out, first, to review both the influence of welding process variables in hardfacing and the important characteristics and properties which determine the effective performance of a hardfacing deposit. Second, the results are presented of a full factorial experiment, which was performed in an effort to evaluate and interpret the effects of arc current, voltage, and polarity, as well as of travel speed, torch stand-off distance, and preheat, on the nature and properties of a commercial flux cored arc welded hardfacing deposit. In this programme, the effects of the welding parameters were evaluated with the aid of a number of computer analyses, with arc current, voltage, and polarity being shown to have the greatest effect: a high arc current (360 A) gives the most s...

Optimum controlling method of arc welding

Abstract: PURPOSE:To set automatically optimum welding conditions even if a work condition and an environment are varied by calculating a weldability index from welding current and welding voltage waveform data, and controlling an output of an welding power source or a wire feed quantity so that the exponential value becomes minimum. CONSTITUTION:As current I0 and voltage waveform data in case of CO2 or MAG welding, an index W for grasping quantitatively the weldability from a short-circuit time TS, an arc time Ta, an average value Is.ave of a current of the short circuit period, an average value Ia.ave of a current of the arc period, etc. is calculated, and by its value, an output of a welding power source or a wire feed quantity is controlled. In this regard, the weldability index W can be derived from an expression I which has used the short circuit time, the arc time, sigmaTS, sigmaTa, sigmaIs-ave and sigmaIa-ave being standard deviations of an average value of the current of the short circuit period and an average value of the current of the arc period, a constant K being the product of those values in a reference welding condition, an average value Ra.ave of a resistance in the arc period, an electric power Pa in the arc period, Ra.ave in optimum conditions, and a regression expression Ri and Pi.

Arc melting and casting method and apparatus thereof

Abstract: Metal material is melted by moving the magnetic flux of electromagnets virtually perpendicular to an arc column to apply Lorentz force to the arc column and the metal material so that the arc column can move over the metal material surface. The movement direction and speed of the arc column are determined by detecting the arc voltage of the arc column. Feed back control is performed by comparing the obtained detection data with preset data so that optimum control is performed, and the molten metal is poured into a casting mold.

Effects of Ultrasonic Vibration on Diffusion Welding of Aluminum(Materials, Metallurgy & Weldability)

Abstract: The ultrasonic vibration has been applied in the diffusion welding of aluminum in an attempt to break up the superficial oxide film of the bond interface. The ultrasonic vibration and subsequent welding have been carried out in a vacuum of 10-2 Pa at 875 K to 893 K under a welding pressure of 1 to 3 MPa. The bond strength increased with the increase in the input power to the transducer and working time of ultrasonic vibration. The increase in pressure to the bond interface during the vibration, however, lowered the bond strength. TEM observation and electric resistance measurement of the bond interface revealed that the application of ultrasonic vibration had the effect of breaking up and dispersing the oxide film, which was closely related to the increase in bond strength. On the fractured surface of joint, dimple patterns, increased with the rise of bond strength. These portions may be regarded as places where the application of ultrasonic vibration promotes breaking up and dispersing the oxide film.

Wire for gas shielded arc welding of stainless steel

Abstract: PURPOSE:To improve weldability and the quality of a weld metal by specifying the contents of Si and S in a wire compsn. and limiting the contents of Al, Ca, and Mg. CONSTITUTION:The compsn. of the wire for welding is made to contain, weight %, = (SiX0.03%) Al, <=0.005% Ca, <=0.005% Mg and is composed of the balance mainly Fe. N is further added at <=0.50% thereto according to need. A stable arc is obtd. in MIG welding and a good bead shape is obtd. if the wire for gas shielded arc welding of stainless steels having such compsn. is used. The generation of the slag in TIG welding is decreased and the strength and corrosion resistance of the deposited metal are improved.

Process for striking an arc in electric welding and welding torch employing said process

Abstract: The invention relates to a process for striking an arc and to a torch employing said process. An electronic ignitor located at a maximum distance of 8 meters from the torch has a high-voltage conductor which leads to a spark gap adjacent the part to be welded. The high-voltage circuit is closed in the region of the zone to be ionized between the welding electrode and the part.

Wire for gas shielded arc welding

Abstract: PURPOSE: To enable the welding work having high depositing speed and excellent arc stability by specifying the containing amount of the metalic powder of the inside of a flux ≥ the prescribed amount and the flux filling rate CONSTITUTION: The more is the metalic powder included in a flux, the better for stabilizing the arc, and in case of the containing amount being ≤ 95 wt%, the stabilized arc sufficiently satisfying is unobtainable and the deposition efficiency is therefore reduced as well, so the lower limit value is prescribed for ≥95 wt% When the filling rate of the flux included in the wire is reduced, the arc becomes unstable and the bead external appearance becomes inferior, and in case of the filling rate being too high spatters and humes are caused and the welding work is deteriorated, so the flux filling rate is prescribed for at 10W40 wt% With the use of this wire the welding of high efficiency having excellent welding operability of high deposition speed and arc stability, atc and high deposition efficiency, is enabled COPYRIGHT: (C)1987,JPO&Japio

Coated electrode for arc welding

Abstract: Disclosed is an electrode comprising a base rod and a hard coating, or a base wire which is coated with a powder or metallic coating of aluminum and optionally of hard coating material that adheres to the electrode and forms a partial pressure of arc activated reactive conductive gas agent in the shielding gas envelope surrounding the arc; and further acts as: an inert agent to shield volatile contaminants; a modifier of the shielding gas envelope's electrical properties; and a heat distributor in the area of the weld puddle by condensation in moisture or oil contaminated environment arc welding.

Mig welding method

Abstract: PURPOSE:To decrease the content of oxygen in a weld metal and to improve low-temp. toughness by magnetizing a welding wire in a welding torch, generating electrostatic attraction force by energization and feeding a welding wire while attracting a flux around the welding wire. CONSTITUTION:An annular electromagnetic coil 21 is provided around the welding wire 1 in the welding torch and a powder adding nozzle 22 is provided below the coil 21 so that the powder of a deoxidizing agent or arc stabilizing agent or a flux 25 contg. said powder is supplied from a supplying port 24, thereto. The wire 1 is magnetized by the coil 21 and welding is executed by supplying continuously the wire to an arc generating part while the powder flux 25 is stuck to the outside circumference of the wire 1 by the electromagnetic force or electromagnetic attraction force around the same and therefore the content of the oxygen in the weld metal 9 is decreased and the low-temp. toughness is improved.

Contact tip for arc welding

Abstract: PURPOSE: To drastically extent the service life of a contact chip by forming the inside periphery part of the tip of a through hole of a welding wire at least of the contact chip for the arc welding of conductive ceramics and preventing the spatter fusion on the welding wire and reducing the hole wear. CONSTITUTION: The inside peripheral surface 2 or the whole of the through hole 4 of the welding wire of the contact chip 7 for the arc welding is formed of the conductive ceramics 2 and 2a with about 1300 Kg/mm 2 hardness. The service life of the contact chip 7 is extended remarkably and the welding productivity is improved drastically because of an infusible characteristic for spatters or the wear resistance of the conductive ceramics 2. COPYRIGHT: (C)1988,JPO&Japio

Burner, in particular electric arc and/or plasma burner for welding and cutting

Abstract: In order to increase the service life of the burners (10), in particular of the burner nozzle (11), the burner (10), which is preferably designed as an electric arc and/or plasma burner, is cooled with a coolant (17) which has a cooling temperature lower than 0 DEG C.

Coated resistance welding sensor

Abstract: The Hall effect current sensor is dipped in a coating of magnetically saturable and electromagnetically saturable material, such as a mixture of powdered nickel in an epoxy binder. The coating has little effect on the sensor's ability to sense the magnetic field attributable to current flow in the welding transformers primary or secondary. The coating shields the Hall effect device from potentially damaging electromagnetic radiation which is produced by the welding apparatus as a by-product of the welding operation.

Lead welding process

Abstract: Two lead members are juxtaposed on an electrically conductive surface forming a first electrode. A direct current electric arc is struck between a second electrode and at least one of the lead members. Inert gas is directed at the area being welded and the arc and work are moved relative to each other. The lead members are typically sheet members and the welds may be of the general types of welds formed with other metals. No metal is added in the welding process.

Tensile and Fracture Properties of an Fe-18Cr-20Ni-5Mn-0.16N Fully Austenitic Weld Metal at 4 K

Abstract: The 4-K tensile and fracture toughess properties of a fully austenitic stainless steel weld are reported. One tensile and two compact tension fracture specimens were tested. The weld was produced by gas metal arc welding using an Fe-18Cr-20Ni-5Mn-0.16N electrode and a 98 percent argon-2 percent oxygen shielding gas mixture. The yield strength of 1015 MPa and average fracture toughness, KIc (J), of 203 MPa•m are higher than those of welds produced with 308L and 316L electrodes and compare favorably with base metal properties. Examination of the fracture surfaces of all samples by scanning electron microscopy showed ductile failure by microvoid coalescence. The suitability of this alloy for welding cryogenic structures is discussed.