Showing papers on "Gas metal arc welding published in 1979"

Method and apparatus for arc welding of metal plates from one side only

Abstract: An apparatus for arc welding of a pair of spaced steel plates from one side only using a grooved back-up plate which gives a good weld bead shape on the under side, gives high linear welding speeds, and avoids contamination of the deposited weld metal by the metal from the back-up plate. A pair of consumable electrodes connected in electrical series between the output terminals of the power source and with one connected by an independent connection to the workpiece are advanced into the weld gap on lines of movement which intersect at a point above the lower surfaces of the plates so that an arc is maintained between the electrodes spaced from the base of the back-up plate groove. A separately energized electrode trails the first two electrodes and deposits a weld bead on the first deposited weld metal while it is still hot.

Effects of fume particles from stainless steel welding on sister chromatid exchanges and chromosome aberrations in cultured chinese hamster cells

Abstract: The frequencies of sister chromatid exchanges (SCE) and chromosome aberra-tions were examined in cultured Chinese hamster cells (Don) exposed to two sorts of fume particles collected from different procedures of stainless steel weldingIt was confirmed that the frequencies of SCE and chromosome aberrations in the cells treated with these fume particles increased with increasing fume doses within the range of the fume concentration tested The fume partticles collected from manual metal arc (MMA) welding were more powerful than those from metal inert gas (MIG) welding In order to cause the same increase in SCE frequency the fume particles from MIG welding needed to be about 100 times as much as those from MMA welding The fume particles from MMA welding showed a higher so-lubility of Cr than those from MIG welding The amount of dissolved Cr from the former was about 60 times as much as that from the latter when culture medium was used as a solvent Small amounts of Mn, Ni, Fe and Mg were also detected in the supernatants of both fume suspensions There were no significant differences in the amounts of these metals as was found with Cr when comparing MMA weld-ing with MIG welding The frequencies of SCE and chromosome aberrations were also increased by the addition of the supernatants of these suspensionsFrom these results, it was assumed that dissolved hexavalent Cr may be involved in the cytogenetic effect of the fume particles from stainless steel welding

Cored type welding electrode

Abstract: A cored type welding electrode which enables good penetration, has an improved range of welding voltages, produces low smoke and provides a weld deposit having good impact properties. The flux contains larger than normal quantities of basic oxides, controlled maximum amounts of acidic or amphoteric oxides and deoxidizers, and a very carefully controlled maximum and minimum amount of combined fluorine in the form of a fluoride.

Process and apparatus for exhausting fumes produced by arc welding

Abstract: During arc welding, optical radiation emitted from an arc is detected by means of a photoelectric device, and an electric detection signal from the photoelectric device is used for controlling the travel of a suction hood along a weld line so that the weld fumes may be exhausted through the suction hood and to insure that the weld metal zone is always covered by the suction hood.

Efficiency of tungsten-inert-gas arcs in very-high-speed welding

Abstract: Previous work with high-speed tungsten-inert-gas (t.i.g.) arcs has shown the need for experiments to determine their melting performance. To achieve this, a new apparatus has been built in which the workpiece is of substantial thickness, rather than the earlier tests which used thin shims as the workpiece. The apparatus also has a calorimetric capability, which allows the magnitude of the total heat input to be determined. Data describing the variation of the weld penetration, width and cross-section over a wide range of arcing conditions (current, speed, tip angle, arc gap) have been determined. Additionally, interesting observations have been made concerning the changing distribution of heat input under certain arcing conditions.

Arc welding apparatus with oscillating electrode

Abstract: A welding process, such as a GMA welding process, employs a consumable electrode with the consumable electrode being oscillated back and forth over the surface of an object to which welding material is to be applied or across the gap between two pieces of metal to be welded together. At the ends of the swings of the consumable electrode an impact force is applied to the consumable electrode to interrupt its movement, thereby causing molten metal at the end of the consumable electrode from which the arc is struck to be impelled therefrom.

Method of welding corrugated metallic materials

Abstract: In an automatic arc welding method for welding metallic materials having a vertically curved weld line, a change in the arc voltage is compared with a arc length setting voltage and the resulting difference signal is used to control the vertical position of a welding torch and hold the same at a predetermined distance from the materials to be welded, while on the other hand in response to a signal generated from an obliquity detector made integral with the torch, the torch is controlled at an angle corresponding to the oblique angle of the materials to be welded and at the same time the welding speed is controlled at a constant value in response to a signal corresponding to the torch angle.

Method of welding utilizing both consumable and non-consumable electrodes

Abstract: A method of welding utilizing consumable and non-consumable electrodes blanketed with inert gas to weld with a minimal amount or no preheating.

Characteristics of high frequency pulsed dc tig welding process

Abstract: As a result of the improved efficiency and quality of the high frequency pulsed DC TIG welding process, much attention has been given to this system. In this paper the effect of pulsed frequency and peak current on arc stiffness and the possibility of increased speed of welding is discussed using low currents. A double switching system makes it possible to obtain higher peak currents at higher pulsed frequencies. Experimental results show that the arc pressure at the arc center is an indication of arc stiffness which increases with increasing pulse frequency and appears to be constant with a pulse frequency more than 5 KHz. Under constant average welding conditions arc pressure is almost proportional to pulse peak current. With a constant width of the weld, the depth of penetration increases with increasing pulse peak current for a constant average welding current. Compared with the penetration of DC TIG process the influence of arc length for the pulsed TIG process is decreased. In the DC TIG process at high speed of travel both fluctuation and discontinuous motion of the anode spot often occurs especially for low welding currents. In the pulsed TIG process, however, with improved arc stiffness fluctuation is reduced and welds can be made with low currents at higher speeds. If the torch is inclined forward the tendency for undercutting along the edge of the bead is reduced permitting even higher speed welding conditions.

Acoustic Emission Weld Monitor System. Data Acquisition and Investigation

Abstract: : The standard weld inspection techniques of radiography and ultrasonics have intrinsic disadvantages The new technology of acoustic emission (AE) has shown an applicability to weld inspection which could overcome such disadvantages This program is directed at utilizing acoustic-emission as a weld monitoring technique on a specific Army welding application The reported work is phase 1 of an Army program to develop a microprocessor-based Acoustic Emission Weld Monitor (AEWM) for the purpose of in-process monitoring of armor plate welding The intended use of this AEWM is to monitor the production welding performed in the fabrication of heavy armored vehicles The objectives of this phase are to: (a) perform laboratory MIG welding of armor plate with controlled induction of critical flaws, (b) collect acoustic emission data generated during the welding, (c) perform a data analysis to correlate the recorded AE data with flaw presence, and (d) predict the accuracy with which AE is able to detect and locate the weld flaws as well as discriminate between flaw types

Method and device of arc starting of electrode consuming arc welding machine

Abstract: PURPOSE: To let initial arc starting be done surely without producing any spatter by short-circuiting a filler core wire and the base metals to be welded while supplying starting electric power of constant electric current between both and changing over the starting electric power to a welding electric power source after the generation of an arc. CONSTITUTION: Sending-out of a filler core wire 16 and spouting of an inert gas 21 are accomplished by switching-on of a welding torch. At the initial arc welding, the core wire 16 is short- circuited to the base metals 18 to be welded, and at this same instant a starting electric power source 32 of constant current is turned on, but predetermined short-circuiting current just flows; therefore the melt-cutting of the core wire 16 does not occur and no spatters are produced. Next, a voltage detecting circuit 36 detects the short-circuit and supplies a reverse run signal of a DC motor 28 to a control electric power source 8, by which the core wire 16 is pulled up and an arc is generated between the same and the base metals 18. When this arc voltage becomes of a proper value, a welding signal is supplied from the circuit 36 to a welding electric power source 22, a starting electric power source 32 and a high-frequency high-voltage circuit 34, by which the core wire 16 is sent out and the electric power source 22 of a constant voltage is turned on in place of the electric power source 32, thus desired MIG welding is started. COPYRIGHT: (C)1981,JPO&Japio

Noncoated electrode wire for arc welding

Abstract: PURPOSE:To obtain a noncoated electrode wire being able to avoid any chance for defect welding such as slag enfolding and/or inferior penetration, by filling the powdered flux made of essential elements such as BaF2, iron oxide, Al, Mg and Mn in a metallic sheath at a predetermined ratio to a quantity of the wire. CONSTITUTION:The powdered flux made of essential elements such as 31-75% BaF2, 2-25% iron oxide, 3-15% Al, 3-15% Mg and 0.5-10% Mn is prepared. Next, the required noncoated electrode wire is manufactured by filling the flux in a metallic sheath made of mild steel etc. at a ratio of 15-30% to a total quantity of the wire. If such electrode wire is used for the arc welding, the welding work efficiency at vertical position should be remarkably improved and higher welding current is also applicable.

Steel wire for ar-co2 gas shielded arc welding and welding method

Abstract: PURPOSE:To stabilize the transfer condition of arc and globules at the short circuit transfer welding and improve bead shapes by such things as addition of a suitable amount of S in particular into the welding wire, limitation of Ti and Al to slight amounts and limitation of the remaining of Ca on the wire surface to a slight amount. CONSTITUTION:In the finish wire drawing process after plating of the Ar-CO2 shielded arc welding wire composed of the wire composition comprising C; 0.2% or less, Si; 0.51-1.20%, Mn; 0.8-2.5%, S; 0.016-0.060%, Ti; 0.03% or less, Al; 0.02% or less, N; 0.010% or less, Ca; the total amount of the wire composition and surface pickup is 0.0050% or less and the rest substantially Fe, seed oil is used as a lubricant and the seed oil is let to remain at 0.001-0.05wt% on the wire surface. By this wire composition, the weld bead width is made wider, the deviation in the aiming of the weld line may be covered and the weld metal of superior weld shape and high toughness may be obtained.

Non-marring spot weld tip

Abstract: To prevent buckling and indentation of a panel being spot welded, a welding tip including an electrode of large load bearing and heat conducting surface is used to spread the load and also efficiently cool the workpiece. The large area electrode is a water cooled copper disk of large mass connected to a support arm by a coil spring. An electrical contactor on the support arm releasably engages the electrode to supply welding current thereto when welding pressure is applied to the workpiece by the welding gun. When the pressure is removed, the coil spring separates the electrode from the contactor.

Double shielded tig welding method

Abstract: PURPOSE: To reduce the pure inert gas consumption in the captioned welding by using pure inert gas for cutting-off electrode from the outside air and using crude inert gas or carbonic acid gas for protecting molten pool and arc from the outside air. CONSTITUTION: Inert gas such as pure Ar gas is used as shielding gas for cutting- off an electrode 5 from the outside air within the inner nozzle 2 of a double shielded TIG welding torch and crude Ar gas or carbonic aicd gas is used as the shielding gas for protecting molten pool and arc from the outside air within an outer nozzle 3. In this way, the amount of using pure Ar gas is reduced and the welding cost reduced. COPYRIGHT: (C)1980,JPO&Japio

Electrode method for welding thin steel sheets

Abstract: An electrode method for welding thin steel sheets using the MIG and/or MAG welding process is made from a copper-manganese alloy with 3-35% Mn, 0-15% Ni, 0.02-0.7% Si and the remainder copper.

Shielding gas welding torch for arc welding using a consumable electrode

Abstract: 1. Inert-gas torch (10) for arc welding with a consumable electrode with two concentric, welding current carrying tubes (15, 10), the most central one (15) of which serves for gas supply and electrode feeding and forms a forced circuit for the cooling water with the external tube (16) lying around it, both tubes (15, 16) ending in a receiving part (18) for a current contact nozzle (19), and with a tubular shell (21) which is electrically insulated against both tubes and has a gas nozzle support (22) with an inert-gas nozzle (23) attached to that end which is assigned to the current contact nozzle (19) whereby an electrical insulation (24) is located between the gas nozzle support (22) and the two current-carrying tubes (15, 16), being characterized by the fact that the insulation (24) has an insulating coating (25) out of well heat-conducting metal with a well heat-conducting, highly heat-resistant polyimid foil coating (26) and is coupled by pressing it to gas nozzle support (22) and external, current-carrying, water-cooled tube (16).

Combined arc welding - with plasma arc from tungsten needle partly overlapping consumable electrode arc

Abstract: An electric arc welding system is based on a first arc between a consumable electrode and the workpiece, and a second plasma arc between a non-consumable electrode and the workpiece. The non-consumable electrode is pref. a tungsten needle which is arranged at a distance from the first electrode and causes the plasma arc to merge partly sideways with the first arc. The partial overlap of the two arcs produces a well defined and stabilized high-temp. zone and fuses the electrode wire always at the same distance from the workpiece. The result is a uniform quality of weld by combining the advantage of both arcs.

Gas metal arc welding method for preparing misaligned tube holes

Abstract: A welding apparatus including a nozzle assembly having a contact extension and a contact tip for guiding a consumable welding wire into a tube hole. The consumable welding wire is guided into the tube hole and an electric current is passed to the wire to produce an arc between the tip of the wire and the sidewall of the tube hole, melting the wire and supplying filler weld to the hole. The nozzle assembly has a gas nozzle; and, during the welding process, an inert gas is delivered into the tube hole through the gas nozzle.

Automatic guidance of burner along seam in MIG welding - where temp. of electrode wire is compared with reference values and any difference is used to adjust burner position

Abstract: Automatic guidance of burner along seam in MIG welding. The actual temp. (Ta) of the consumable electrode is monitored during welding, and is compared with a prescribed value (Tref); and difference between the two temps. is used to adjust the position of the burner. The two temps. are pref. converted into electric signals, where Ta is first compared with a horizontal prescribed value (Thref) and then with a desired vertical value (Tvref). Pref. the welding appts. includes a sensor employed to measure the temp. of a consumable electrode wire; and a comparator used to feed signals to adjusting devices altering the horizontal and vertical positions of a burner holder. Used e.g. on numerically controlled coordinate machines used to guide the burner along a desired path, where the invention compensates for variations in dimensional tolerances.

Welding methods and apparatus including alternate weld metal depositions along opposite sides of a weld

Abstract: Welding methods and apparatus, wherein a welding electrode is oscillated by a motor-driven oscillator in back and forth movements transverse to a weld joint, and an alternating welding current is supplied to the welding electrode in timed relation with the welding tip oscillations so that weld metal is deposited along opposite sides of the weld joint in parallel paths without deposit of weld metal at the center of the weld joint.

Forming method for heat and wear resistant coating for blast furnace tuyere

Abstract: PURPOSE:To form a heat and wear resistant coating for a blast furnace tuyere and to elongate the tuyere life by adding one or more kinds of finely divided, specified substrances in formation of a molten layer of a specified metal on the base metal surface of the tuyere. CONSTITUTION:When wire rod 6 made of copper, Ni, Monel metal, titanium or the like is build-up-welded to base metal 11 by means of tip gas nozzle 2 of a welding torch for MIG welding or the like, fin grains 8 of one or more out of tungsten carbide, titanium carbide, boron carbide, etc. of a fixed grain size are added from supply vessel 5 to molten pool 9 through pipe 4 and grain feeding torch 1 fixed to nozzle 2 with jig 3 at a certain angle, forming tough deposited metal 10. Thus, a superior heat and wear resistant coating of high mechanical strength is easily formed by automatic welding to elongate the life of the title tuyere to 2-4 times as long as that of a conventional method.

Plasma ARC Welding of High-Performance-Ship Materials

Abstract: : The plasma arc welding process has been evaluated for use in the fabrication of high-performance-ship materials, which include HY steels, PH stainless steels, and titanium and aluminum alloys Welding parameters and mechanical properties of plasma arc keyhole mode welds in varying thicknesses were determined for the above materials Additional information was generated through an evaluation of the commercial practice of plasma arc welding It was found that this type of welding is a viable fabrication technique for the intended application The materials of interest can be welded from one side in one or two passes in thicknesses of 1/2-in (125-mm) or less with less distortion than conventional arc welding processes Filler metal consumption is minimal, mechanical properties are satisfactory, and required operator skill levels are not exceptionally high The highly cost effective plasma arc welding process could be implemented with existing technology in the fabrication of high-performance-ship materials

Welding apparatus including means for depositing the weld metal along parallel paths

Abstract: Improved methods and apparatus for welding, wherein during welding the welding electrode is oscillated laterally of the weld path, and the welding current pulse frequency and oscillation frequency are correlated whereby weld metal droplets are deposited when the electrode is at its limit of movement away from center at each side of the weld path. During each cycle of oscillation of the welding electrode, a controlled number of weld metal droplets is deposited at each side of the weld path. An electrical circuit controls the electrode oscillation frequency and the welding current pulse frequency to be in correlation, and controls the number of weld metal droplets deposited at the opposite sides of the weld during each oscillation of the welding electrode.

Nickel foil to aluminium component connection - uses combined ultrasonic and resistance welding

Abstract: The aluminium component is a sheet metal cathode element for an electron tube, and the nickel foil forms the connecting tag for this element which has to be secured to its contacting point by thermal treatment. The connection of the foil and the element is carried out by resistance-ultrasonic welding. The metal parts to be welded are preheated prior to welding by a voltage between 2 to 4 V and a pulsed current of 150-500 A. During welding the sonotrode pressure force is limited to 100 N/sq. mm.

A method of and an apparatus for marking metal objects

Abstract: A method of and an apparatus for marking metal objects, especially metal billets at high temperature. The marking will enable selective identification of the object in question. A marking head (3) is utilized, having at least one electrode (4) for providing characters built up in a matrix form on the object (1) by means of an electric arc process. The characters consist of matrix parts in the form of welded-on projections, in which case a consumable electrode is utilized preferably in conjunction with the principles for gas metal arc welding, or alternatively of matrix parts in the form of recesses, in which case a non-consumable electrode is utilized, preferably in conjunction with the principles for plasma are cutting. The marking head (3) preferably comprises a sequence of electrodes (4) which are activated selectively in conjunction with relative displacement between the marking head and the metal object (1) to provide the desired character matrix parts. By sensing that necessary electrode current has been consumed in conjunction with an activation of an electrode, a confirmation can be obtained that the desired character matrix part has actually been provided.

Welding a copper-nickel clad ship -- copper mariner ii

Abstract: Welding is carried out using the SMAW process by welding the steel first with E7018 electrodes and then welding from the clad side with Enicu-2 filler metal. An antifouling and corrosion resisting material can be used for a nearly maintenance-free ship hull with improved fuel economy.

Multielectrode arc welding method

Abstract: PURPOSE:To make possible welding of superior efficiency and the toughness of weld-heat-affected zone by employing an AC MIG welding method and performing multilayer welding of a plural pool system. CONSTITUTION:Preceding beads W3 are formed by the molten pool W1 relating to a preceding composite wire 1f, and the succeeding beads W4 are successively formed on the upper layer of the preceding beads W3 by the molten pool W2 relating to a succeeding composite wire 1r. Slag W5 is formed on the preceding beads W3 in front of the succeeding composite wire 1r, but since this slag W5 is thin, it is melted away without any problem by the arc of the succeeding composite wire 1r. In this way, the preceding and succeeding beads are formed approximately simultaneously by the respectively independent plural molten pools W1, W2 and the multilayer welding in one run is performed, hence the quantity of heat input is dispersed to the wires 1f, 1r and the low temperature toughness of the weld-heat affected zone is improved.