Showing papers on "Arc welding published in 1981"

Pulse arc welding machine

Abstract: A pulse arc welding machine in which the repetition frequency of the pulse currect is unaffected by the frequency of the power source and the mean value of the pulse current applied can be accurately controlled over a broad range while the arcing is maintained stable. A pulse peak current supplying circuit is connected in series with an arcing region formed between a consumable wire electrode and a material to be welded between the output terminals of a standard direct current source while a base current supplying circuit is connected in parallel with the pulse peak current supplying circuit. The pulse peak current supplying circuit and the base current supplying circuit are both composed of a switching element such as a transistor coupled in series with an inductive element. Diodes are provided for suppressing high voltage transients in the circuit.

Arc welding simulator

Abstract: An arc welding simulator for instructional use includes a handpiece that supports a retractably mounted heat tube. The handpiece and heat tube are sized and shaped to resemble an actual electric arc welding apparatus, including an electrode. The simulator includes a drive mechanism for retracting the heat tube at a predetermined rate that simulates consumption of an actual arc welding electrode. A source of hot, pressurized air provides a stream of hot air through the heat tube. The simulator is used in combination with heat-sensitive paper that is preferably imprinted with a predetermined pattern resembling the pattern of movement that is followed during actual arc welding. A trainee uses the simulator by attempting to superimpose a thermal trace on the imprinted pattern. The resulting trace provides a permanent record of a trainee's success in tracking the imprinted pattern and correctly holding the simulator so as to maintain the tip of the heat tube positioned at a proper angle and distance with respect to the surface of the paper. In preferred embodiments of the welding simulator, a heating element is provided at the tip of the heat tube in combination with a small diameter air orifice tube so as to provide a narrow stream of heated air from the tip of the tube. Additionally, the simulator may be provided with a tilt switch and an acoustic alarm to alert the trainee when the simulator is moved from a predetermined angular position.

Infrared Temperature Sensing of Cooling Rates for Arc Welding Control.

Abstract: : It is known that the weld metal mechanical properties of quenched and tempered steels are dependent upon cooling rate, which is presently indirectly controlled by specification of heat input. A method to directly control weld metal cooling rate would result in more consistency in achieving required mechanical properties. In the present investigation the use of commercial infrared sensing equipment was explored as a means of real-time monitoring of weld metal cooling rate. Infrared equipment has a distinct advantage over other temperature detecting systems in that it requires no physical contact with the work, thus affording a minimum amount of interference with the welding process, and is therefore a potentially useful detector for an adaptive feedback welding control system based on cooling rate. It was found that infrared thermography appears to offer considerable promise for welding control by providing weld metal cooling rates which are: (1) reproducible, (2) sensitive to variations in welding conditions, and (3) relatable to cooling rates as measured by plunged thermocouples. (Author)

Pulse arc welding method and device in which pulse current and background current have a constant current characteristic

Abstract: A pulse arc welding device includes a power source which produces a background current and pulse current imposed on it. A voltage drop across the arc is measured and when such a voltage drop deviates from a predetermined level, either one of background current, frequency of the pulse current and pulse duration of the pulse current is controlled to maintain the voltage drop across the arc constant.

Hot wire type arc welding device

Abstract: PURPOSE: To make the reduction in size at a low cost possible by flowing wire heating current and arc current from one unit of an electric power source by the use of transistors CONSTITUTION: Arc current I 1 flows in a route of an electric power source 13, a transistor TR 1 , base materials 3, a molten pool 8, a non-consumable electrode 1 and a shunt 18, and generates the arc 4 Wire heating current I 2 flows in the route of the power source 13, a transistor TR 2 , a power feed tip 7, a wire 5, the pool 8, the arc 4, the electrode 1, and the shunt 18, and heats the wire 5 These currents are controlled by the TR 1 , TR 2 so that the applied voltage V for wire heating of constant voltage characteristics and the full arc current I 0 of constant current characteristics are obtained COPYRIGHT: (C)1983,JPO&Japio

Narrow gap arc welding process and apparatus therefor

Abstract: A narrow gap arc welding process comprises steps of defining a narrow gap between a pair of members to be welded arranged so as to face each other at a predetermined distance, feeding a consumable electrode into a guide cylinder which is movable along the narrow gap, and generating electric arc between the tip of the consumable electrode and the members to be welded to unite them with each other, wherein the consumable electrode, while being deformed plastically to have a wave-like pattern with a pitch of about 10 to 30 mm and a molding width of about 2 to 5 mm depending on welding conditions, is fed into the narrow gap with the direction of the molding width being in line with the direction of the width of the narrow gap and the direction of the tip of the consumable electrode being changed so as to point out one after the other facing edge of the members to be welded alternately at a high frequency. Also, an apparatus for practicing the process is described.

Automatic device for changing an electric welding gun, operated by the arm of a programmable manipulator

Abstract: An automatic device for changing an electric welding gun, operated by the arm (11) of a manipulator, in which two elements (10, 50), one carried by the manipulator arm and the other by the gun, can be connected together by the first element being made to approach and fit into the second; each element is provided with ducts (13) for passage of the liquid for cooling and controlling the opening of the electrodes (63); valve units (31) connect said ducts (13) to each other when the two elements (10, 50) are fitted together; the approach of the two elements is guided and checked, and hydraulically controlled hook portions (42, 71) lock together and separate the elements in accordance with the programming of the manipulator; each element is also provided with male cones (66) and female cones (16) provided on or in copper units (14) in order to fit into each other and establish electrical contact between the manipulator and gun.

Arc welding gun with handle assembly

Abstract: A welding gun handle assembly connectable to a supply cable supplying a consumable welding electrode, shielding gas and electrical power, all under the control of a trigger operated switch in the handle assembly including a relocatable thumb rest which may be attached on either side of the handle assembly above the trigger of the switch so that the trigger may be operated in a natural manner by both right and left handed operators, a grip portion having finger grooves for placing at least one finger over the trigger of the switch, cooling vents through the handle assembly to permit circulation of cooling air therethrough, connection apparatus for connecting the welding gun to the supply cable, a gooseneck assembly and an adapter on the handle for connection therewith and a replaceable liner for guiding the consumable welding electrode from the connection apparatus to the welding gun, through the removable gooseneck

Control apparatus for an arc welder

Abstract: An arc welder is provided with a phase control circuit by rectifying elements to simplify the construction of the arc welder and improve the performance and operability. The arc welder is further provided with a storage control circuit to enable the retrieval of stored data of the same welding conditions. A union/individual control circuit is provided to eliminate troublesome adjustment of potentiometers.

Method of making a filled electrode for arc welding

Abstract: A welding electrode of the filling type for machine or hand welding is formed by providing a longitudinally extending stepped ridge along one edge of a strip which is then bent transversely so that the opposite edge lies in the step and is a projecting portion of the step, underlies the gap, the resulting tubular member receiving the filling. The junction is then welded by tungsten inert gas or electron beam welding to close the shell and seal the latter.

Effect of Residual Tensile Stresses on Threshold Level for Fatigue Crack Propagation in Welded Joints of SM50B Steel

Abstract: The fatigue crack propagation rate and the stress intensity threshold level were measured on welded joints which were made by three kinds of welding processes, manual arc welding with covered electrode, gas metal arc welding, and submarged arc welding The specimens were 200 mm wide center notched type The material was a SM50B steel 20 mm in thickness The fatigue crack propagation properties of the weld metal and the heat affected zone of these welded joints were found to be quite similar to each other and inferior to that of the base metal The stress intensity threshold level of welded joints was about one fourth of that of the base metal It is assumed that the inferiority of welded joints in crack propagation properties may be caused from the tensile residual stresses distributed in the middle part of the specimens The removal of the tensile residual stresses by postweld heat treatment could improve welded joints in the fatigue crack propagation properties The fatigue crack propagation properties and the stress intensity threshold level of welded joints after the postweld heat treatment are similar to those of the base metal

Pulse arc welding method

Abstract: PURPOSE:To eliminate the over-thrust at the starting and to cause transfer to the arc in a short time by setting >=1 of the respective set values of the peak current, background current, pulse width and pulse frequency of the pulses at the arc starting larger than the set values in a steady time. CONSTITUTION:Before a wire 1 arrives at base materials 3, the pulse-like voltage of which only the set value of the background current is set larger than the set value in a steady time is applied to the wire and the wire feeding is started. When the wire 1 short-circuits to the base materials 3, the set value of the background current in particular is set larger and therefore the input heat to be applied upon the wire 1 is larger than that in the prior art, whereby the wire 1 is melt-cut easily and is transferred to the arc in a short time. In the case when the pulse width and the pulse frequency are increased similarly, the heat input upon the wire 1 is also increased and the wire 1 is easily melt-cut and is transferred to the arc in a short time. According to these methods, the wire feed troubles such as buckling of the wire owing to the failure in the arc starting are eliminated.

Optoelectronic weld travel speed sensor

Abstract: The sensor of the present invention is adapted for use on the electrode holder of a manual arc welding apparatus. The sensor comprises a first optical fiber having a receiving end disposed in a first zone adjacent to the weld puddle produced by the arc welder so as to receive radiation indicative of the weld temperature in that zone, and a second optical fiber having a receiving end disposed in a second zone rearward of the first zone so as to receive radiation indicative of the weld temperature in the second zone. Each optical fiber transmits received radiation to a respective photosensor, which produces an analog electrical signal in accordance with the level of the radiation. These two signals are processed and compared continuously to produce an output signal indicative of the travel speed of the weld bead produced by the manual arc welding apparatus.

Welding wire for automatic arc welding

Abstract: A welding wire for automatic arc welding, which is particularly suitable for use in build-up welding operation for the purpose of providing hard surface to a metal die. The welding wire consists of a continuous tubular metal casing and a core composition charged in the interior of the casing and comprises such amounts of Ni, Si, B, Nb and C as essential alloying elements that the deposited metal contains at least 40% of Ni, 3-8% of Si, 0.1-0.4% of B, 0.3-1.8% of Nb and 0.2-1.5% of C, all by weight. Preferably, either a practically pure Ni strip or an Fe-Ni alloy strip is used as the material of the casing, and the core composition in the form of a powder mixture contains necessary amounts of Ni, Si, B, Nb and C, optionally with the addition of a small amount of Zr. The deposited metal given by this welding wire has high wear resistance and good antifrictional property and seldom suffers from weld cracks.

Rotary arc-welding method

Abstract: In a rotary arc-welding method which comprises: directing a nozzle substantially vertically toward a weld zone of objects of welding; feeding a consumable welding electrode through said nozzle eccentrically from the center axis of said nozzle toward said weld zone; feeding welding current to said consumable welding electrode to produce an arc between the tip of said consumable welding electrode and said weld zone to weld said objects of welding with each other by means of the arc heat; rotating said nozzle to cause a circular movement of said arc from the tip of said consumable welding electrode corresponding to the eccentricity thereof; and, feeding a shielding gas toward said weld zone to shield said arc and said weld zone from the open air; the improvement characterized in that: the diameter of said consumable welding electrode is limited within the range of from 0.8 to 1.2 mm; said welding current is limited within the range of from 400 to 800 amperes; and, the number of rotation of said nozzle is limited within the range of from 3,000 to 6,000 r.p.m.

Control system for pulsed DC arc welding power supply

Abstract: A control system for a pulsed DC arc welding system power supply is disclosed. The control system operates to automatically adjust the pulse width of the current pulses supplied at the arc gap by the power supply to control the power flow to the work pieces at the arc gap. An example of such a control system for a conventional pulsed DC arc welding system power supply comprises a variable resistance device connected in parallel with a normally closed time delay switch. This system is electrically connected in an impulsar control circuit of the power supply. The control system automatically changes the resistance within the conventional impulsar control circuit to provide an adjustment within the control circuit to alter the impulsar output signal which controls the pulse width of the current pulses supplied by the power supply.

Method of producing an axially symmetrical hollow shaft

Abstract: Within the spindles made of several parts (1, 2) assembled for the construction of machines, engines and gear boxes, there is provided within the spindle a sealed chamber (4, 5) which is symmetrical in rotation. Parts (1, 2) are obtained through creep extrusion and welded together approximately in their radial plane. This bond may be achieved by means of friction welding, electron bombardment welding, arc welding, shrink ring fitting, force fitting or caulking. The lightening and the facilitation of the manufacture as well as the strength of the spindles are thereby achieved, in particular for the spindles having extremities with decreasing diameters and for which conventional processes produce a considerable amount of worthless turning chips or similar.

Rotating arc welding method.

Abstract: A welding method for rotating a nozzle (3) within a groove (2) by deflecting a welding electrode (9) from the central axis (a), which comprises the steps of bringing the central axis (a) of the nozzle to the center of the groove (2) by smoothing the varying value of welding current or voltage at every half clockwise or counterclockwise rotation of the nozzle and controlling so as to move the nozzle horizontally at a right angle of the welding direction, and maintaining the height with respect to the groove (2) at a prescribed distance by smoothing the varying value of the welding current or voltage and controlling so as to move the nozzle (3) vertically so that the difference between the value and the set value becomes zero.

Plasma-jets in arc welding

Abstract: Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1981.

Micro-arc welding/brazing of metal to metal and metal to ceramic joints

Abstract: Method and apparatus for micro-arc brazing and welding of metal to metal or ceramic. The control of arc heat flux density is accomplished by controlling the ambient gas pressure and providing an argon, argon/5% hydrogen or other inert gas atmosphere. The discharge current is controlled so as to provide an arc which is operable at 100 microamps to 20 amps. Prior to welding or brazing, the work is cleaned by high frequency electrical discharge cleaning techniques using high energy ions from either the ambient gas or from an electrode. By providing a small amount of DC during the high frequency discharge a "tinning" capability is established. The welding or brazing may be formed in a closed chamber so that arc stabilization can be accomplished.

Consumable electrode type arc welding machine

Abstract: PURPOSE:To provide a titled welding machine which permits the reduction in size and capacity of a main transformer and is stable in welding performance, by converting AC of a commercial frequency to AC of a high frequency with a converter and an inverter, and supplying the same to the primary side of a high frequency transformer. CONSTITUTION:After the AC of a commercial frequency supplied to input terminals 100, 100' upon starting of welding is converted to DC with a converter 12, an inverter 14 is operated to convert the DC output of the converter 12 to high frequency AC. This high frequency AC is dropped in voltage with a high frequency transformer 18 and is supplied to a bridge circuit 20, which supplies the rectified current to terminals 101, 101' by firing the 1st, 2nd thyristors 20a, 20b or firing the 2nd, 3rd thyristors 20b, 20c. Since no large welding current can flow to the converter 14 and the inverter 12, the converter and the inverter of small capacity having intricate functions are usable, and the consumable electrode type arc welding machine which is small in size, light in weight and is in expensive is obtained.

Consumable arc welding torch

Abstract: An arc welding apparatus that imparts a rotational movement to the tip of the consumable electrode to cause drops of molten metal to be thrown by centrifugal force against the sidewall of the slot between the two metal workpieces being welded.

Square wave power supply for arc welding

Abstract: An alternating current constant potential power source suitable for use in a submerged arc welding process. An inductor (Z1) of large value is placed in the D.C. output of thyristor bridge (SCR1 to SCR4) fed from a transformer (T1). The four thyristors (SCR1 to SCR4) and the inductor (Z1) are controlled in such a manner as to provide essentially square wave currents. The square wave is adjustable in amplitude with very rapid zero crossing. The thyristor bridge (SCR1 to SCR4) is controlled in a firing sequence so as to prevent free wheeling of the square wave inductor (Z1) at polarity reversals of the voltage supply. The inductor (Z1) is capable of storing vast amounts of energy, and the thyristor firings are timed to deliver this energy into the arc. Two regulating sub-systems respectively responsive to arc voltage and arc current operate together to control the output. The regulator time response is designed to ignore short instantaneous perturbations and regulate around a long term output voltage with high gain. This voltage loop is active at all times. However, defeating the current feedback on arc starts permits the source to deliver high current on demand during cold starts.

Arc welding process using a consumable stranded wire electrode

Abstract: An arc welding process using a consumable stranded wire electrode which is formed either by integrally intertwisting a plurality of wire elements substantially of the same sectional area such that the lines connecting center points of adjacent wire elements do not form a regular polygon in a sectional plane or by integrally intertwisting a plurality of wire elements of different sectional areas such that the lines connecting center points of wire elements of larger diameter do not form a regular polygon in a sectional plane wherein the consumable electrode is imparted with a bending trait and contacted with a surface on the inner periphery and at the outlet end of a conducting tip, and the arc is directed toward a center weld line to thereby obtain a stable arc.

Granular flux for pipe welding

Abstract: An agglomerated welding flux especially designed to produce tandem arc seam welds having low profiles, increased penetration, and minimal undercutting. The flux includes aluminium oxide and silicon dioxide in the form of kyanite, magnesium oxide, manganese oxide, and sodium silicate as a binder.

Inactive gas shield arc welding material

Abstract: PURPOSE:To make highly efficient the welding work of a 9% Ni steel, by manufacturing a wear electrode wire with a base material in which specific amount of C, Si, Mn, P, S, N, O, REM, and Ca is included to a steel and the ratio of the REM/Ca is taken as a specific range. CONSTITUTION:A steel which includes by weight, 0.01-0.07% C, <0.7 Si, <6% Mn, <0.03% P, <0.03% S, 8-13% Ni, <0.005% N and <0.007% O, and <0.08% REM, <0.008% Ca with the range of 3-10 REM/Ca ratio, and the rest of Fe and inevitable impurities is made. This steel is made in wire through rolling and drawing and wound on a reel for wear electrode wire. The srability of arc is improved in conducting the similar composition MIG welding of 9% Ni steel and the workability can remarkably be improved.

Gas shielded arc welding method

Abstract: PURPOSE:To impart high breakdown toughness value to a vertical joint weld zone by limiting the amount of the O2 gas or CO2 gas contained in an Ar gas of a shieding gas for welding and specifying the wire components of a consumable electrode. CONSTITUTION:As a shielding gas for welding, an Ar gas contg. 2-12% O2 gas or an Ar gas contg. 5-25% CO2 gas is used. A wire controlled to a ragne from 0.15 to 0.35 in carbon equivalent C.E. (formula) of the wire component is used as a consumable electrode. In addition, 0.03-0.12% Ti, 0.003-0.015% B are contained as the components of the wire, and further <=0.08C, 0.3-0.6% Si, 1.0- 2.5% Mn, <=0.10% P, <=0.010% S, <=0.005% N are contained and if necessary, one or two kinds of <=4.0% Ni and <=0.5% Mo are contained. If with this method vertical welding is performed, a high breakdown toughness value is given to the vertical joint weld zone of a low temperature steel used in a low-temp. region.

Pulse arc welding method

Abstract: In a pulse welding method, an optimum pulse current waveform defined by the amplitudes of the current pulse and base current and the width of the current pulse is maintained throughout the welding operation while the average welding current is varied by changing the frequency of the current pulse