Showing papers on "Gas metal arc welding published in 1981"

Low expansion laser welding arrangement

Abstract: An arrangement for laser beam welding wherein at least one of the components being welded is formed of a material which is substantially transparent to radiation at the wavelength of the laser welding beam. A layer of welding material is placed over the surface area of the weld joint, and is a type of material which is substantially absorbent of radiation at the wavelength of the laser welding beam. The welding material is then irradiated by the laser beam through the component which is substantially transparent thereto for a sufficient period of time to cause melting of the welding material and fusion thereof to the two components being welded. The present invention has particular applicability to welding with a Nd-YAG laser of components formed of silica-containing material, such as fused silica or titanium silicate, and wherein the welding material placed at the weld surface area is a titanium based material. The present invention is also particularly attractive for weld locations which are physically inaccessible to direct irradiation, but can be irradiated through the material which is substantially transparent to the laser welding beam.

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

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.

Method of welding for hard surfacing

Abstract: A method of welding for hard surfacing comprises feeding a powdery mixture, prepared by adding at least one of the powders on NbC, VC, and TiC to the powder of an alloy steel containing either Fe, Ni, and Cr, or Fe and Cr as the chief components, to an arc produced between a base metal of iron or steel and a nonconsumable electrode shielded by an inert gas, and thereby forming a weld metal on the base metal.

Welding wire feed device

Abstract: A compact welding wire feed device is provided capable of being mounted directly on a welding head carriage. The device comprises a ball bearing having an inside race with tangential entrance and exit guides to the race adjacent to opposite axial ends of the bearing. A hub member has an outside diameter less than the inside diameter of the race so that the hub member can be coaxially received in the race and a welding wire passed through the entrance guide and wrapped around the hub and out the exit guide. By now side-loading or expanding the hub against the inside of the race and driving the hub rotationally, the welding wire is continuously fed out the exit guide. The coaxial relationship of the hub and race provides for a very compact structure thereby permitting mounting of the wire feed directly on a welding head carriage adjacent to a weld head or even permitting the feed wire itself to be used as an electrode in a MIG welding system. In certain applications, the bearing itself may be used without the hub simply to form a ninety degree bend in the weld wire with substantially no friction for proper positioning and guiding of the wire.

Shielding arrangement and method for TIG

Abstract: A gas shielding arrangement and method is disclosed for use with tungsten inert gas (TIG) welding and the like, consisting of an inner, primary flow of an inert gas such as argon, passing about the electrode and weld area, and an outer radially spaced secondary flow of hydrogen gas, completely enveloping the flow of inert gas and ignited by the welding arc to provide a flow of burning hydrogen gas which consumes the atmospheric oxygen penetrating into the flow to minimize oxidizing of the weld metal. The flow of hydrogen gas also minimizes dissipation of the inert gas to conserve and improve its shielding effect. The heat generated by the burning hydrogen heats the portions of the workpiece surrounding the weld to produce superior welds with improved grain structure by minimizing the quenching effect of the weld created by conduction of the weld heat into the surrounding metal.

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 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.

Two electrode welding with different currents supplied to the electrodes

Abstract: In a two electrode welding method wherein welding is carried out by means of arcs struck between two electrodes and a parent metal, the two electrodes being located in side-by-side, spaced-apart relation in a direction in which the welding surface advances and movable relative to the parent metal, a portion of the parent metal is preheated by the arc struck between the leading electrode and the parent metal, and a preheated portion is melted by the heat of the arc struck between the trailing electrode and the parent metal when the former has moved to a position above the preheated portion of the latter to provide a deposited metal. The method has particular utility in applications where metal of high heat conductivity, such as copper, is welded.

Method and apparatus for plasma welding

Abstract: The invention relates to a method and an apparatus to perform plasma welding, by providing a cooling water temperature detector at the inlet side of cooling water in the plasma welding torch, controlling the temperature at the inlet side of the cooling water running into the plasma welding torch at a set temperature of more than 4° C. and less than 18° C., starting a plasma arc when the temperature of the cooling water reaches a specified point after starting to pass the cooling water, and moving the base metals and the torch relatively upon lapse of a specified time allowed to form a keyhole after start of the plasma arc.

Electric resistance welding using energy beam in combination

Abstract: PURPOSE:To perform welding of high quality free from welding defects using relatively simple device by irradiating an energy beam to an apex which becomes the welding point of an wedge-shaped object to be welded and making combined use with electric resistance welding. CONSTITUTION:High frequency voltage is applied to contacts 4, 4 disposed on the edge part 2 of a tubular body 1 for manufacturing an electric welded tube etc. to heat the edge part 2, and welding is performed at the apex of the wedge- shape. An energy beam F is irradiated in the direction of the apex of the wedge by a laser irradiating device and mirrors 6, 7, 8, 9 etc., and the corner part 21 and thick central part 22 of the edge part are heated uniformly to prevent occurrence of welding deffects. Efficiency of uniform heating can be increased by supplying highly ionizing gas to a space just in front of the apex of the wedge of the weld zone to generate plasma, and work efficiency of welding can be improved by controlling heat input of welding automatically.

Tube welding method for large diameter steel tube

Abstract: PURPOSE:To efficiently weld a joint with superior low-temperature toughness, by performing the one-run welding of a blank steel plate for a steel tube, which has limited components, under specific edge and welding conditions. CONSTITUTION:A steel plate for a steel tube to be used has a 12-40mm. plate thickness while containing 1 or >=2 kinds among 0.01-0.15wt% C, 0.10-1.30wt% Si, 0.50-2.00wt% Mn, <=0.02wt% P, <=0.02wt% S, <=4.0wt% Ni, <=0.50wt% Mo, <=0.50wt% Cr, <=0.05wt% Al, <=0.05wt% Ti, <=0.15wt% V, <=0.05wt% Nb, and 0.0010-0.0050wt% B, and the balance Fe with impurities. An edge is formed <=1/4 as deep as plate thickness (t) on the internal surface side, 3mm.-<=1/4 as deep as the plate thickness on the route face side, and <=2/4 as deep as the plate thickness (t). On the internal surface side, submerged-arc welding with high current density is employed, and a Ti-B basic flux is used. Then, a successive sealing bead is provided on the external surface of the edge and gas metal arc welding with a high current value is carried out for small-diameter wire; and the surface is treated by one-run submerged-arc welding.

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.

Method and device for production of welded can body

Abstract: PURPOSE:To prevent splashing by peak current and to make stable welding in a wide welding current range possible in welding a can body of a non-ferrous metallic plate or various surface treated steel plates as a blank material, by forming the welding current waveform into a square waveform. CONSTITUTION:In the stage of using thin steel sheets such as tin plates, TFS, zinc plated steel sheets or the like or sheets of non-ferrous metals such as Al, Cu alloys or the like as a blank material, superposing both end edge parts thereof and subjecting said parts to seam welding, a rectifier for voltage controllable DC current, a switching circuit for converting the DC current to square wave AC and a chopping mechanism for controlling the switching circuit are contained in a welding power source. If the welding current is converted to the square wave current having no peaks with said power source, there is no plashing by peak current because of the absence of peak current unlike with ordinary sine wave current, and the stable welding is made possible in a wide current value range.

Covered electrode containing zirconium for shielded metal arc welding

Abstract: A covered electrode for shielded metal 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 covered electrode comprises such amounts of Ni, Si, B, Nb, C and Zr as essential alloying elements that the deposited metal contains at least 40% of Ni, 3-8% of Si, 0.1-0.5% of B, 0.3-2.0% of Nb, 0.2-1.5% of C and 0.01-0.20% of Zr, all by weight. In a preferred form, either Ni wire or Fe--Ni wire is used as the core wire, and the covering contains necessary amounts of all the essential alloying elements except Ni. The deposited metal has high wear resistance and good antifrictional property, and the presence of Zr is highly effective for preventing the occurrence of weld cracks.

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.

Pulse width modulated pulsed DC arc welding

Abstract: A method of arc welding is disclosed. Specifically, a method of pulsed DC arc welding is disclosed wherein the pulse width of the current pulses are modulated to maintain a constant time averaged power flow to the work pieces being welded. This method of arc welding is especially useful with a type of pulsed DC arc welding wherein the ratio of peak current to maintenance current is maintained at a selected high value and the current is cycled in a time duration whereby oxides on the surface of the work pieces are dissipated as the weld is made. When used with this type of pulsed DC arc welding the present method is especially suited for fluxless welding of aluminum work pieces, such as thin wall aluminum tubing used in making heat exchangers for air conditioning systems.

Ultraviolet emissions from the arc-welding of aluminum-magnesium alloys

Abstract: Measurements of the ultraviolet radiation from gas tungsten arc welding (GTAW) and gas metal spray arc welding (GMAW) of various alloys of aluminum and magnesium were made using a microcomputer controlled rapid scan spectroradiometer. Low concentrations of magnesium in aluminum were found to yield radiation of considerably greater biological activity than non-magnesium alloys and, at a distance of one meter from the arc, up to a thousand times that of sunlight at the earth's surface. The use of GMAW consumable electrode wire containing 5% magnesium led to an order of magnitude greater biological activity than non-magnesium wire. “Biological activity” in this regard refers to the effectiveness in producing skin-shielded DNA response, and as such may be related to the potential for carcinogenicity. Magnesium in small concentrations was found to be important to radiation emission owing to the ease of vaporization into the arc and to the existence of magnesium emissions in the ultraviolet. Emission dependenci...

Mig welding method

Abstract: PURPOSE:To prevent short circuit of a wire and base metals and to maintain arcs stably by detecting MIG voltage at all times and increasing MIG current when said voltage drops below the set voltage. CONSTITUTION:MIG current is set with a potentiometer 16 for setting of main current, and the current to be added to the main current when an arc length becomes short is set by a current potentiometer 17. An arc voltage for preventing short circuiting is set by a potentiometer 20 for setting voltage, and is compared with the voltage from a voltage detecting circuit 28 by a comparator 19. When said arc voltage is lower than the set value, a switch S3 of an analog switch 15 is closed, and the current value from the potentiometer 17 is added to the current value from the potentiometer 16. The added current value is compared and amplified with the current value from a CT27 for detecting current by a differential amplifier 14, and a transistor 10 for controlling welding current is controlled by the deviation signal obtained by said comparison, whereby the welding current is controlled.

Method of welding using a covered tungsten electrode

Abstract: A method of welding which utilizes a metal electrode core encased within a pre-sintered ceramic insulating sleeve. The method comprising, preplacing a welding wire in the welding kerf formed between the pieces to be welded, tacking the welding wire in place such that the wire abuts the surface of the pieces to be welded, guiding the metal core electrode rod encased in a ceramic pre-sintered sleeve over the welding wire, and simultaneously, torching the welding wire so that a uniform weld deposit is formed.

Welding method for metallic tube of small diameter

Abstract: PURPOSE:To weld a metallic tube smoothly without generating any pinhole in the stage of TIG welding of a metallic strip to a cylindrical shape by controlling the mixing ratio of gaseous argon and helium as shielding gases at the start of welding and at the stationary state. CONSTITUTION:A metallic strip is formed to a cylindrical shape to make a metallic tube 1 of small diameter, and the joining edges 1a thereof are subjected to DC TIG welding by a welding torch 10. At this time, gaseous He and gaseous Ar are supplied as shielding gases to the torch 10 through pressure valves 16, 18 and throttling valves 20, 22. The mixing ratio of He with Ar is so controlled as to be made small prior to starting of welding and to be made large at the steady time. The quantity of the Ar to be used is set at >=80% at the start of welding and <=30% at the steady time. The gases are controlled by converting the pressure detected with pressure sensors 32, 34 to flow rates with pressure- flow rate converters 36, 38, and regulating the openings of the valves 20, 22 by means of controllers 28, 29.

Arc welding equipment

Abstract: PURPOSE:To improve the semiautomatic welding sense and uniformity of a bead by promoting shaking of a molten pool overlapping pulse voltage of a speific current crest value, which is lower frequency than the pulse MIG welding method, to said method. CONSTITUTION:The transformer for supplying pulse voltage 1 delivers the first pulse voltage of commercial power supply or its twice frequency to the consumable electrode 11, and gives the current wave form Ip1. Pulses synchronizing with this wave form are inputted to the counter 13, which is set the number of count by the circuit 14, from the generating circuit 12. A count end signal at the time when said count number reaches a set value is added to the wave forming circuit 15, and forming of a wave form is made. On the other hand, with said signal, resetting of the counter 13 is made repeating the same operation again. Also, said signal is added to the gate circuit 16 of SCRs 2 and 3, and the gates G1 and G2 are controlled. Then, the second pulse voltage, which has a lower frequency and its crest value is 1.5-2.0 times comparing with the first pulse, is generated. Thus, the current wave form Ip2 can be obtained, and shaking of a molten pool is promoted.

Electrode for welding

Abstract: PURPOSE:To prevent the swing of a wire during welding by using an electrode of a curved wire insertion hole for the electrode of a welding torch. CONSTITUTION:In a CO2 gas welding method and other MIG welding methods using a fine diameter wire, the degradation in current collecting effect owing to the swing of a wire occuring in the winding habit, etc. of a reel is prevented by curving the wire insertion hole of the electrode in the torch. For example, the curved electrode having the bend (l3) of a fixed direction and fixed amount at all times is used for the electrode 11 having the insertion hole of a wire 5 in a torch 1. As a result of this, even if there is the bend (l3) at the end of the wire 5, the swing of the wire 5 owing to the rotation and tilting of the torch hardly occurs and this enables the elimination of weld defects. Here, the combination use with a curved type torch 12 is more effective than the straight type torch 1.

Rotor of rotary electric machine

Abstract: PURPOSE:To prevent the generation of cracks from a weld padding by inclining the angle of the side of a ring-shaped welding slot by the specified angle with respect to the vertical axis so that the bottom of the slot becomes narrow. Said slot is provided at the periphery of rotor bars and an end ring. CONSTITUTION:A rotor bar 2 is inserted into a slot 3 of an end ring 4, whose shape is the same as that of the rotor bar 2. A slot 5 is provided at the periphery of the rotor bars 2 and the end ring 4 so that the angle theta of the side of said slot is inclined by 10-45 deg. with respect to the vertical axis 9 and the bottom of the slot 5a becomes narrow. A padded portion 6 is provided in the slot 5 by continuous welding or intermittent welding that is applied only in the vicinity of the rotor bar 2 in the MIG welding method and the like. In this method, since the faulty welding at the boundary of the padded portion 6 is eliminated and the angle theta is determined in the range wherein the maximum allowable stress can be obtained, the cracks are not generated on the boundary.

Inert gas metal arc welding method

Abstract: PURPOSE:To achieve the stabilization of the arc and make possible the controlling of globule migration mode, deposition amount, etc. by providing a consumable electrode for MIG welding and plural consumable electrodes for TIG welding respectively to the central part and its circumference and encircling the wire tip and arc of the former by the arc of the latter. CONSTITUTION:For example, consumable electrodes 3, 6 and 7 for MIG and TIG welding are disposed as shown in the figure, and with these as anode, and the welding work 1 as cathode or by making these to the opposite polarities, the welding is performed. This causes the arc A generated by the central electrode 3 to be effectively converged by the arcs B, C having the directivity in the central direction generated by the surrounding electrodes 6, 7, thereby enabling powerful arc throttling power, that is, pinch force, to be obtained. This pinch force and the wire tip are effectively preheated by the surrounding arc and are thereby pointed at the end, by which the stable spray arc may be maintained and globule migration mode is improved. Further, the amount and shape of penetration may be controlled by dispersing the welding current to the electrodes 3 and 6, 7.

Method for submerged-arc welding a very low carbon steel

Abstract: A method for producing line pipe of high strength and high toughness by the submerged-arc welding process in which a welding wire containing 0.18-0.55% C. is used, Ti or B or both are added to the welding wire or flux or both, and a steel containing 0.005-0.06% C. is welded by the submerged-arc welding process, whereby both Ti and B are caused to be present in the weld metal.