Showing papers on "Arc welding published in 1982"

Electronic welding apparatus

Abstract: An electric welding apparatus which, for controlling at least one welding parameter, such as welding voltage or welding current, comprises a switching mode power supply (SMPS) as control element, the switching mode power supply preferably being regulated on the primary. The actual values of voltage and current are taken from the output of the switching mode power supply and fed to an analog control circuit. The set values of voltage and current are fed to a microprocessor via an entry keyboard, and in the microprocessor they are stored in a memory and passed on in analogous form to the analog control circuit which carries out a comparison of set value and actual value and, in dependence thereon, produces an error signal that is fed to a pulse width modulator of the switching mode power supply. The pulse width modulator is connected to the driver stages of the switching stages of the switching mode power supply, which switching stages are designed as boost regulator of buck regulator, and thus a pulse width modulation of the current pulses of the switching stages is effected in dependence on the difference between actual and nominal value. The converter section of the switching mode power supply preferably is designed as a modified single-ended buck regulator or as a push-pull full bridge, wherein it is operated at a fixed clock frequency of about 25 kHz. The secondary coil of the transformer of the switching mode power supply being either direct in connection with the output connection terminals of the switching mode power supply, or a secondary rectifier is connected between the secondary coil and the output connection terminals, whereby the secondary rectifier can be bridged by switch means.

Acoustic measurement of the arc voltage applicable to arc welding and arc furnaces

Abstract: A new technique is proposed for determining the time evolution of the voltage in the column of an electric arc. It is based on measurement of the sound wave produced by the arc, which is shown to depend on the rate of change of the electrical power fed to the arc column. There is no electrical connection to the arc circuit so that the errors usually caused by the voltages induced by the arc DI/dt's and ohmic drops in the arc electrodes are avoided. The technique is of interest for controlling the voltage or length of the arc and offers applications in arc welding and the operation of arc furnaces.

Arc welding guide tube with non-adhesive tip

Abstract: A guide tube for guiding a wire (23) of filler metal in an arc welding machine and for applying arc current thereto comprises a metal body (80) having a longitudinal bore (82) through which the wire passes. Near the front end of the tube there are two transverse passages (95) housing respective ball (96) which are urged to project into the bore by respective spiral compression springs (97). These serve to keep the wire pressed against the opposite side of the bore to maintain good electrical contact. The springs are held in by a sheath (100) fitted over the end of the tube. The sheath also serves to keep an end piece (50) in place. Both the sheath and the end piece are made of refractory material which is electrically insulating and which is non-adhesive to spattering metal from the weld melt. This helps to prevent the front of the tube getting clogged up in operation.

Arc welder power supply with fail-safe voltage reducing circuit

Abstract: A fail-safe voltage reducing circuit for an arc welder. The welding transformer has two primary windings connected in parallel across a power source. After an arc is struck, if the arc is then broken for a predetermined time period, the circuit automatically disconnects one of the primary windings from the power source, thereby reducing the voltage across the welder's output terminals to a safe standby voltage lower than the full open circuit voltage. If the voltage has not been reduced after a second predetermined time period, the fail-safe feature of the circuit automatically disconnects both primary windings from the power source, thereby completely removing all power from the welder.

Arc welding robot control system

Abstract: An arc welding robot control system in which a control console stores the welding conditions upon the completion of a welding cycle. When a suspension of the welding cycle is commanded during its execution, the welding cycle is effected under the stored welding conditions and its robot is stopped at a suspension point. The control console may further include two memories for respectively storing the position of the suspension point and a current and the next position of the robot with coefficients for a linear interpolation. When the welding cycle is restarted after the robot has been displaced from the suspension point to another point, the torch is automatically returned back to the suspension point along a line passed through the two points and points interpolated through calculations of the content of the memories. The torch is moved through taught points and a similarly interpolated point.

Power source for arc welding

Abstract: PROBLEM TO BE SOLVED: To reduce the equipment cost by arbitrarily setting the length of a connection means of a power source unit output terminal to a welding control unit input terminal to reduce the weight of a cable and to facilitate adjustment of the output voltage. SOLUTION: A power source unit 51 converts the commercial AC voltage input 100V into the DC voltage 141V by a transformer 2 and a rectifier 3, and outputs between output terminals 52, 53 through a DC reactor 7. A smoothing capacitor 4 is connected between input terminals 55, 56 of a welding control unit 54, and a switching element 6 is chopper-controlled by a chopper control circuit 5 to output the welding voltage through the DC reactor 7. The output terminal 52 is connected to the input terminal 55 and the output terminal 53 is connected to the input terminal 56 through cables 57, 58. The weight of the cables can be reduced to 30% that of the conventional cables, the workability is improved, a coaxial cable can be dispensed with even when the pulse current is used, adjustment of the output voltage can be facilitated, and the power loss can be reduced. COPYRIGHT: (C)1997,JPO

Method of controlling a weaving path of a welding torch in arc welding with a consumable electrode

Abstract: A method for controlling a weaving path of a welding torch to trace a welding line in consumable electrode arc welding, including: detecting in a rightward weaving stroke of weaving motion a welding current level IL1 at the left end position of the weaving motion and a minimum current level IL2 during the period of the rightward weaving stroke and in a leftward weaving stroke of weaving a welding current level IR1 at the right end position of the weaving motion and a minimum current level IR2 during the period of the leftward weaving stroke; calculating the values of differential current (IL1 -IL2) and (IR1 -IR2) in the rightward and leftward weaving strokes, respectively; comparing and computing a disparity, if any, between the differential current values; and shifting the position of a median point of weaving motion according to the extent of the disparity in the differential current values.

Controller for arc welding robot

Abstract: PURPOSE:To eliminate the laboriousness of teaching and to improve the working efficiency of welding by the constitution wherein only the control commands of specific operations except the common operations of welding modes in an arc welding robot are taught to the robot CONSTITUTION:In the case of MIG welding, if welding conditions for the time T1 until a robot body operates and a crater treating time T2 are inputted by shifting an external selecting switch 32 to an MIG welding position, a current command and a voltage command are outputted to a welding power source 4 from an apparatus control part 23 In the case when WIG welding is required, the timers necessary for welding sequence are T1 and T2 as well as a timer T3 until a wire is fed, and the teaching of the positions and attitude information as well as other welding conditions may be the teaching which is beforehand inputtedThus all required for the operator is to shift the switch 32 to a TIG welding position and to teach only the T1, T2 and T3 Thereupon a current command and a wire feed command are outputted from the part 23 to the power source 4 according to the welding sequence

A new approach to the weldability of nickel-base As-cast and power metallurgy superalloys

Abstract: The repair of nickel-base superalloys such as those used in the first and second stages of the rotating sections of a gas turbine is examined. Welding is affected by stress and temperature levels of the blade, wall thickness, and material composition. Steps to achieve crack-free welds include preheating above 600C (1112F) for GTA and plasma arc welding and above 900C (1652F) for EB welding. It is concluded that crack formation can be prevented by controlling the cooling rate during welding; that hardness measurements provide useful results for crack-free welding using GTA, plasma, friction, and electron beams; and that small differences in chemical composition and homogeneity can have a decisive effect on weld behavior.

Consumable electrode type arc welding power source

Abstract: A power source includes first and second control circuit for controlling the current provided during short-circuit and arc intervals, respectively. A transistor in series with the power supply is controlled in response to either of the control circuits.

Method of welding titanium alloy parts with titanium insert

Abstract: A method of welding opposite end surfaces of two titanium alloy parts kept in alignment by a high energy-density welding process such as electron beam welding, laser beam welding or TIG arc welding, characterized by closely interposing an insert member of either practically pure titanium or Ti-Al binary alloy containing up to 3 Wt % of Al. Owing to thorough alloying of the inserted titanium with the constituents of the fused base metal, the weld metal in a weld joint obtained by this method is sufficiently high in both strength and toughness. By an optional postwelding heat treatment, the strength of the weld metal can further be enhanced.

New fluxes of improved weld metal toughness for HSLA steels

Abstract: Weld metals which are microalloyed with Ti and B can show excellent properties even at low temperature. However, welding consumables which can consistently add optimum amounts of Ti and B to weld metal were relatively unknown. Therefore, new TiO/sub 2/-B/sub 2/O/sub 3/ bearing fluxes, which can add Ti and B to weld metal by reduction of their oxides in the fluxes, were developed. When TiO/sub 2/ was a main component, it was necessary to substitute BaO, MgO or some other basic component for CaO in order to eliminate the precipitation of perovskite (CaTiO/sub 3/) and have a good weldability. The new fluxes were shown to be able to consistently microalloy weld metals with optimum amounts of Ti and B (about 0.02% and 0.0045%, respectively). Fracture appearance transition temperature of the weld metals was sufficiently low and only slightly deteriorated with the addition of Nb in the as-welded metal. The new fluxes were successfully applied to the welding of node cans of offshore platforms, a sea berth, LPG tanks and ships.

Arc welding gun with gas diffuser and external cooling conduit

Abstract: A welding wire gun operable in the high temperature environment of a high current density welding system. The welding gun includes a tubular member through which welding wire and shielding gas are adapted to pass. A gas diffuser member is mounted upon one end of the tubular member and, in turn, supports a welding tip therein such that the end of the welding tip projects beyond the diffuser in the direction of the joint to be welded. Additionally, the welding gun is constructed to provide for flowing of a coolant material around the tubular member proximate the diffuser member for maintaining the welding tip below its melting or distortion temperature. A tubular nozzle member is supported at one end from the diffuser member and extends beyond both the diffuser member and the welding tip in such a way as to define an annular shielding gas chamber about the diffuser and welding tip. Gas passages formed through the diffuser communicate with the annular gas chamber and are angularly oriented with the central axis of the diffuser and welding tip so as to maximize the velocity and minimize turbulence of the gas flow through the gun to thereby maintain a high energy shielding gas envelope around the welding wire and weld puddle.

Arc welding method and electrode for narrow groove welding

Abstract: A narrow groove arc welding process includes angular oscillation of a non-consumable electrode having a tip which is radially displaced with respect to the central axis of the electrode. This provides for improved arc sweep and can be combined with prior art lateral and pivotal electrode oscillation techniques. A non-consumable electrode for use in this process is provided with a radially displaced tip. The electrode can be easily replaced by detaching it from a permanent rod electrode.

Flux cored wire for self-shielded arc welding

Abstract: PURPOSE: To improve welding workability and resistance to blowholing and to obtain good bending performance by filling a specific amt. of a powdery and granular flux contg. a specific ratio each of metallic fluoride, Al, Mg, rare earth element in the form of an oxide and alloy, C and Mn into a steel sleeve. CONSTITUTION: The granular flux contg. weight % each of 0.3W1.8 metallic fluoride except rare erarth, 1.5W3.5 Al, 0.2W1 Mg, 0.1W0.5 rare earth element of ≥1 kinds among Ce, La, Sm, Sc, Y, Pr and Nd in the form of the oxide and alloy, 0.01W0.3C and 0.20W2 Mn is packed into the steel sleeve 1 at 5W25% by the total weight of the wire. More specifically, the flux components and the compounding ratios thereof as well as the rate of filling the flux into the metallic sleeve are adequately adjusted. The resistance to blowholing in particular in addition to mechanical properties such as strength and toughness required generally for the weld metal are thereby improved. The wire of which the spatters are smaller-grained and are decreased and which has the good bead appearance and shape is obtd. COPYRIGHT: (C)1986,JPO&Japio

Tubular composite arc welding electrode for vertical up welding of stainless steel and nickel-base alloys

Abstract: In a tubular composite electrode for depositing stainless steel or nickel-base alloy weld metal, satisfactory performance in vertical up welding is achieved through the inclusion in the electrode core of a slag mix comprising 15 to 60% weight percent zirconium dioxide.

Hot wire arc welding torch assembly

Abstract: A hot wire welding torch assembly includes a nonconsumable metal electrode 12, a filler metal 6 fed to a weld puddle 11 fomed by an arc 10, a collet body 15 for holding the electrode, a shielding gas nozzle 3, and a torch body 1 molded from a synthetic resin for coaxially mounting the collet body and shielding gas nozzle. A highly dielectric and heat-proof insulating bushing 14 is provided between the torch body and a clamping holder 2 for mounting the torch body 1 to a filler metal torch 4 to prevent any relative slippage between the two torches and avoid electrical shock hazards.

Arc-welding seam-tracking applications employing passive infrared sensors

Abstract: In an arc welding operation seam tracking is accomplished by determining the level of infrared radiation in a selected bandwidth, from at least two points lying in a direction forward of the arc torch travel and on opposite sides of the seam. Signal levels from the infrared detectors are compared and the difference signal is used to laterally position the arc torch. In this way, automatic seam tracking is accomplished thus facilitating robotic welding processes.

Consumable electrode type pulse arc welding machine

Abstract: PURPOSE:To prevent the fluctuation in arc length and make globule migration correct by providing circuits which fractionate welding current, determine the integrated value for one pulse period, compare the same with a set value and regulate pulse frequency. CONSTITUTION:The set quantity of a wire feed speed command circuit 1 is put into a function generator 4 which determines the area of a pulse current waveform corresponding to the feed rate and inputs the same to a comparator 5. The welding current from a detecting circuit is amplified 11, and is separated to the current in a base priod and the current in a pulse period by a selecting circuit 12. The peak value of this pulse current is compared with the set value of a peak current command circuit 13 in a comparator 14. The differential signal thereof is inputted to a peak current value setting circuit 15, which controls the peak current value constant. At the same time, the separated pulse current is integrated to the current value of one pulse period in an integrating circuit 6, the output whereof is compared with the integrated value from the function generator 4 in the comparator 5. The differential signal thereof is put into a pulse frequency setting circuit 9 which compares the same with the pulse frequency signal corresponding to the wire feed and decreases the pulse frequency.

Consumable electrode type arc welding device

Abstract: PURPOSE:To provide a titled welding device which improves welding performance and the efficiency in welding work by the constitution wherein the waveform of welding current is pulsed to form a spray arc and a separate filler wire is fed under electrical heating into the arc. CONSTITUTION:Welding current is flowed from a power source 24 through a tip 16 to a consumable electrode 10, which is fed by a roll 12 driven by a motor 14, to generate an arc 20 between the electrode and a base material 60. The adequate pulse waveform corresponding to the feed speed of the electrode 10 is formed in the welding current by a frequency setter 46, a pulse width setter 48 and a switching element 34 to make the droplet from the electrode 10 into a spray. A filler wire 26 is at the same time fed into the arc 20 while it is heated by part of the welding current supplied from a power feeder 32 to adjust the penetration rate of the molten metal. The heating current for the wire 26 is controlled by a frequency setter 46, a pulse width setter 50, a current comparator 59, a switching element 36, etc. so that said current is kept at <=1/2 of the welding current and is made zero during the quiescent period of the pulse.

Arc welding machine

Abstract: PURPOSE:To perform stable welding free from arc breaking by forming the welding current at the AC arc welding into the current waveform approximate to a square wave. CONSTITUTION:The anode of a thyristor S1 and the cathode of a diode D1 are connected to one terminal 2a of the secondary winding 2 of a welding transformer 1, and the anode of a thyristor S2 and the cathode of a diode D2 are connected to the other terminal 2b. The cathode of the thyristor S1 is connected to a welding electrode 3, and the anode of the diode D1 to the electrode 3 by way of one welding L1 of a reactor 6 which is wound with the a pair of windings L1, L2 on the same iron core. The cathode of the thyristor S2 is connected to a base metal 7, and the anode of the diode D2 to the base metal 7 via the winding L2 of the reactor 6. The winding directions of the windings L1, L2 of the reactor 6 and the connections to the windings L2, L2 are so set that the directions of the magnetic flux generated at every half cycle of the welding current supplied to the windings L1, L2 invert alternately. Therefore, the welding current approximate to a square wave is obtained.

Automatic arc welding machine

Abstract: PURPOSE:To improve the end of welding and to form the top end of a wire so as to have a good arc starting characteristic for the succeeding time by controlling antistick timing and pulse output for prohibiting formation of a spherical lump at the top end of the wire when welding ends. CONSTITUTION:A device 1 which feeds automaticaly a wire, a power source 2 which outputs a DC voltage for welding, a transistor (TR) 3 which controls the welding output therefrom and a main control circuit 6 which controls the device 1, the power source 2 and the TR3 are provided to an automatic arc welding machine. The circuit 6 controls the power source 2 to generate the voltage, the device 1 to feed a wire 7 and the TR3 to be driven so that an arc is generated between the wire 7 and base metals 5 to be welded. The circuit 6 feeds a welding stop instruction and a stop signal to the device 1 upon ending of welding but a wire feed motor does not stop on the spot on account of inertia and therefore the circuit 6 retards the voltage stop by as much as the antistick timing to allow the wire 7 to burn up. The sticking of the wire 7 to the base metal 5 is thus prevented.

Method and apparatus for positioning a welding torch in automatic electric welding

Abstract: This invention relates to automatic welding of confronting edges of two bodies between which is a groove to be filled with filler material and, more particularly, to conditioning, processing and use of control signals for automatic operation.

Consumable electrode type pulse arc welding method

Abstract: PURPOSE:To suppress irregular rocking of a welding metal and to obtain stable penetration, by periodically varying a peak current value of a welding current having a pulse waveform, in case of consumable pulse arc welding. CONSTITUTION:A peak value Ip of a welding current (i) controlled to a pulse waveform is controlled, for instance, to a sine wave, so that it is varied periodically within a range of a current which is larger than a critical current value Ic. In accordance with this variation period, arc force is varied, a weld metal of a molten pool 7 follows little by little in the advancing direction of a wire 8. Accordingly, stable penetration which scarcely causes variance is obtained.

Apparatus and method for viewing molten pools in arc welding

Abstract: An optical apparatus for use in viewing an arc welding process wherein the view is directly parallel to and around the electrode thus allowing the electrode tip to block the arc from direct view. The light seen is reflected from the mirror-like molten pool revealing the edge of the said pool which is a parameter directly analyzed by video picture analysis to control an arc welding process.

Development and Application of Dabber Gas Tungsten Arc Welding for Repair of Aircraft Engine, Seal Teeth

Abstract: Dabber TIG welding can be defined as a modification of an automatic TIG welding system. Modifications, both mechanical and electronic, combine to cause an intermittent filler wire feed to the molten weld puddle. This interrupted action allows for momentary cooling of the weld puddle. Energy input, as heat, for a given time span is reduced by this action. In addition the interruption allows solidification of the puddle with resultant narrow, uniform bead. This weld mode is characterized by shallow heat affected zones and precise weld build up configurations. This paper describes the application of this procedure to Gas Turbine Seals.Copyright © 1982 by ASME

Gas shielded arc welding method

Abstract: PURPOSE:To perform titled arc welding with good arc stability by bringing the electrodes of multielectrodes using solid wires closer to each other and providing specific phase differences between the alternating currents conducts through the electrodes. CONSTITUTION:In gas shielded arc welding, solid wires of >=3.2mm. diameter are used for electrodes to make multiple electrodes of >= electrodes. The distance between the electrodes is set at =600A alternating currents are flowed to a preceding electrode 11 and a succeeding electrode 12; at the same time, + or -60-120 deg. phase differences of either one is zero, it turns out that always the voltage of a certain prescribed value is applied upon the other electrode. Hence, an arc C is generated between the electrodes 11 and 12 when the arc (a) between the electrode 11 and a base material 2 is broken momentarily upon attainment of zero voltage upon the electrode 11, whereby the gaseous atmosphere of the surroundings is thermally ionized and the extinction arc is refired surely.

Arc welding method

Abstract: PURPOSE:To prevent formation of a projecting bead in the stage of MAG or CO2 buried arc welding by performing TIG welding utilizing a hollow electrode in succession to said welding after a specified interval. CONSTITUTION:A base material 1 is subjected to buried arc welding by an MAG or CO2 buried arc welding electrode 2. A molten metal 5 formed by this welding solidifies with lapse of time thereby forming a weld metal 6. A TIG welding torch 7 having a tungsten electrode 8 of a relatively large diameter having a hole 8' at the central part is performed in succession to said welding at the distance L when the metal 5 is still in a molten or semi-molten state. The electrode 8 has a hole at the central part and therefore the arc is liable to spread and since the arc pressure is decreased by the presence of the hole, the formation of a projecting bead is thoroughly prevented without boiling of the metal 5 and without unstability in the arc.