Showing papers on "Shielding gas published in 1981"

Laser welding method

Abstract: PURPOSE:To fill perforated holes thoroughly with molten metal and to prevent the formation of blowholes by subjecting iron and steel materials to be welded to laser welding by using shielding gases consisting of inert gases mixed with suitable amts. of active gases according to the kinds of said materials. CONSTITUTION:Iron and steel materials to be welded are subjected to laser welding by using shielding gases consisting of inert gases such as argon and helium mixed with suitable amts. of active gases such as oxygen, nitrogen and carbon dioxide according to the kinds of said materials. For example, if the materials to be welded are carbon steel, low alloy steel, high tensile steel, martensitic stainless steel and ferritic stainless steel, the shielding gases consisting of the compsns. of TableIare used. If the materials to be used are austenitic stainless steel, the shielding gases consisting of the compsns. of Table II are used. Thus the formation of babbles in molten metal is prevented in welding.

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

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.

Narrow groove welding torch

Abstract: A narrow groove welding torch having an internally insulated metallic housing and a rectangular cross section with cooling ducts and shielding gas ducts disposed within the housing.

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.

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.

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.

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...

Gas shielded arc welding method of hydrogenninduced cracking resistance steel

Abstract: PURPOSE:To improve the weldability under the ultimate conditions of hydrogen- induced cracking resistance steels by selecting the proportion of the inert gas in a shielding gas and the Ti content in a welding wire. CONSTITUTION:At the time of subjecting the hydrogen-induced cracking resistance steel base materials of >=0.10 in the value of the parameter A shown by the formula contg. rare earth elements and Ca being hydrogen-induced cracking suppressing components to shielded gas welding at welding current 600-50A, the shielding gas comprising mixed gases of >=20vol% inert gas and CO2 is used. Further, the Ti content in the welding wire composition is increased or decreased from a reference content 0.03% according to the mode of globule migration. If at least one of the proper selections of these wire composition and shielding gas composition is adapted, the good beads having sufficient short-circuiting times are obtained. This method is adapted to circumferential welding etc. of pipes for transferring petroleum and natural gas drawn in areas of extreme cold weather or from deep sea bottoms.

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.

Factors Influencing Stress-Corrosion Cracking of High-Strength Steel Weld Metals

Abstract: The stress-corrosion cracking (SCC) behavior of high-strength steel weld metals, as indexed by KIscc, was examined with emphasis on the relative influences of yield strength, electrochemical potential, welding process, and weld metal composition. The weld metals were from weldments fabricated by the gas metal arc (GMA) or gas tungsten arc (GTA) process. Filler metals with four different compositions—designated 120S, 140S, AX140 and HY-130—were used. The multi-pass welding procedures and their associated thermal cycles produced very complex martensitic-bainitic type microstructures. The GTA weld metals were considerably more fine-grained and more highly tempered than the GMA weld metals. This enhanced the fracture toughness of all four of the higher strength GTA weld metals but improved the SCC properties of only two GTA weld metals—HY-130 and 140S. The effectiveness of microstructural influences on SCC behavior is correlated with the sulfur content of the weld metals assuming that hydrogen is the cause of SCC in these materials. The role of sulfur is presumed to be that of catalytic poison for the hydrogen recombination reaction which increases opportunities for nascent hydrogen absorption. The results show that the weld metals with improved SCC properties contain the lower concentrations of sulfur.

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.

Gas-shielded arc welding torch

Abstract: An arc welding torch having electrode gripping means is located rearward in the torch head and remote from the welding operation which occurs in a carefully formed, unerratic, cooling atmosphere of shielding gas enveloping the electrode and flowing in collimated fashion.

Nozzle for narrow groove mig welding

Abstract: PURPOSE:To obtain a titled nozzle which consists in coupling a welding core opposing to the groove, a contact tube, supply and return pipes for cooling water, a shielding gas supply pipe and impurity gas suction and discharge pipes into one row plate shape and which makes narrow groove welding easy even for plates. CONSTITUTION:A shielding gas supply pipe 4 and suction and discharge pipes 5, 6 for impurity gas are disposed in one row, by holding a contact tube 1 for feeding a welding core 9 to the groove and a cooling water feed pipe 2 and its return pipe 3 for the purpose of cooling water circulation at the center. The outside surface of the entire part of this configuration is covered with a heat-resistant electrical insulator 10, whereby the nozzle for narrow groove MIG welding is formed. According to this nozzle for welding, the groove width that can be welded may made extremely small. In addition, the flow alignment to the groove bottom is accomplished despite the suction and exhausting of the impurity gas around the weld zone and the spouting of the shielding gas supplied 4 from the fine diameter injection port. Hence, the purity of the shielding gas may be increased.

Narrow groove three o'clock arc welding method of al or al alloy

Abstract: PURPOSE:To prevent joint defects and improve welding efficiency by converting the direction of the magnetic line of force in synchronization with the oscillation in the thickness direction of an electrode while supplying a shielding gas thereby directing the arc to the top and under groove faces and performing three o'clock welding. CONSTITUTION:An electrode 4 is fed at an angle theta3 of intersection >90 deg. which a consumable electrode A and the weld line assume within the three o'clock groove of the narrow groove butt joint of Al or Al alloy. Thence, a pure gaseous He or a shielding gas mixed with >=50% gaseous He and <=50% gaseous Ar is supplied to around the electrode 4. In welding the under face 2b side of the groove, a magnetic field is formed in the space including an arm column 5, so that the arc column 5 is directed to the lower groove face 2b direction. In welding the upper face 2a side of the groove, the angle of intersection of the electrode 4 and the top face 2a of the groove is kept at 0-15 deg., and the electrode 4 is oscillated in the thickness direction; at the same time, a magnetic field is formed and the direction of the magnetic line of force is converted in synchronization with the changing-over of the insertion direction stroke and the extraction direction stroke in the oscillation, whereby the arc column 5 is directed in the top, and under groove directions 2a, 2b and the welding is thus accomplished.

Monitoring method for shielding gas for welding

Abstract: PURPOSE:To prevent the cocurrence of welding defects by detecting the amount of the inclusion of air into a shielding gas from the amount of NO2 obtained by oxidizing the sample of the shielding gas and controlling said amount rapidly and accurately in a shielding gas welding method. CONSTITUTION:The arc 3 is generated between a W electrode 1 and the material 2 to be welded, and the circumference of a weld zone 2A is shielded by an Ar gas 5 released from a shielding gas nozzle 4. During welding, a part of the shielding gas 5 is sampled by a sampling probe 7, and is sent into a reactor 8 made of quartz glass. The NOx in the shielding gas in the reactor 8 is oxidized to NO2 by the ultraviolet rays 9 radiated from the welding arc 3 and the amount thereof is measured with a visible absorption type NO2 measuring device 10. From the value thus measured, the amount of the air included in the shielding gas 5 is estimated, and the amount of the included air is decreased, whereby the occurrence of welding defects is prevented.

Gas shielded arc welding method

Abstract: PURPOSE: To stabilize the welding arc, to reduce the generation of spatters, and to obtain beautiful bead appearance by generating the welding arc between zinc coatd steel materials and a consumable electrode in a specific shielding gaseous atmosphere CONSTITUTION: A gaseous mixture consisting of argon for the greater part (more preferably 95W99%) and a small amt (more preferably 5W1%) of gaseous oxygen is used as a shielding gas, and welding is executed by generating the welding arc between zinc coated steel materials and a consumable electrode The oxide of zinc is generated by this Since the sublimation point of zinc oxide is about 1,725°C and that of molten metal is about 1,400°C, the zinc oxide solidifies before the molten metal solidifies, and this makes it possible to decrease the influence that zinc vapor gives upon the shielding gaseous welding atmosphere COPYRIGHT: (C)1982,JPO&Japio

Inert gas shielded arc welding method

Abstract: PURPOSE:To achieve welding of higher performance by letting the globule transfer mode of MIG welding be granular transfer smaller than electrode diameter and weaving and feeding the separately provided two filler metals at arbitrary periods to the right and left centering at the molten pool in the welding advance direction. CONSTITUTION:An MIG welding wire 1 is set in the welding position of the weldwork 6 and an electric power source 8 is turned ON. The wire shorts to the welding work via the feed rollers 2 and welding tip 3, thereby generating arc. At the same time, shielding gas 15 is fed through a shielding gas sealing port 5. The welding conditions under which globule diameter becomes of granular form smaller than the wire diameter are selected by the electric power source. Filler metals 10, 10' are fed to welding pool 16 by being controlled by filler metal control units 12, 12' and are oscillated at arbitrary periods by weaving mechanisms 14, 14'. The filler metals are melted by the MIG arc heat and join with deposited metal, thereby yielding the good weld zone.

Hydrogenassisted Cracking in HY-130 Weldments.

Abstract: : The relative susceptibility to hydrogen-assisted cracking of AX-140 welds on HY-130 plate material and on AX-140 all-weld-metal specimens was investigated. Controlled amounts of diffusible hydrogen were introduced into these weldments by using the pulsed-current gas metal arc welding process with additions of hydrogen or moisture to the shielding gas. The critical hydrogen content required for crack initiation and propagation was determined by the augmented strain cracking (ASC) test. Crack initiation and propagation were monitored with acoustic-emission techniques. Although hydrogen-assisted cracking invariably initiated in the fusion zone, it frequently propagated into the heat-affected zone. Crack propagation through the weld metal was not always related to the solidification structure. The critical hydrogen content to initiate cracking in AX-140 welds on HY-130 plate was approximately 1 ppm, whereas in AX-140 welds on AX-140 all-weld-metal the critical hydrogen content was approximately 3 ppm. This difference is cracking susceptibility was ascribed to the difference between the base-metal and the fusion-zone analyses.

Method and device for underwater arc cutting in nuclear reactor

Abstract: PURPOSE:To prevent gas from assuming radioactivity and escaping to the atmosphere at the time of under water cutting having radioactivity by capturing the decomposed gas of the water produced during consumable electrode type arc cutting which feeds only the injection water of a minimum amount of gas formation, burning the same and returning it into the water in the reactor. CONSTITUTION:In order to cut a material M to be cut in the water W in a nuclear reactor pressure vessel V, a wire is fed from a device 17 to the torch 14 of a consumable electrode type arc cutter 1, and jet water is fed by a pump 19. At this time, no shielding gas is fed. Then, the arc is produced between the member M and the end part of a wire, the part melted by the heat thereof is blown off by the jet water, and the member M is propressively cut by the advancing of a traveler 12 and the moving of the jet water. During the cutting, the water is decomposed by the arc heat to produce H2 and O2, and bubbles G ascend. These are captured by a gas capturing part 2, and the accumulated gas is successively ignited and burned by the nozzle above the water of a condensate part 3. The produced water is cooled by being prevented from escaping to the atmosphere by the enclosing wall of a return water part 4, flows down and returns into the water.

Welding method for sintered hard alloy heat resisting material

Abstract: PURPOSE:To enable welding with a weld zone excellent in quality and free from cracks by welding an Ni base sintered hard alloy heat resisting steel combining solution welding by arc welding method and specified heat treatment after welding. CONSTITUTION:In manufacturing a turbine blade by welding using an Ni base sintered hard alloy heat resisting steel, the material to be welded is heated beforehand to 500-650 deg.C, and TIG welding is performed while inserting a filler wire in inert atmosphere using Ar gas as shield gas. Minimum necessary welding current to melt the material to be welded is used and welding is performed in a short time. Before temperature of the weld zone drops to below 850 deg.C (point A), the material is put in a heating furnace set at 850 deg.C beforehand, heated to 1,100-1,200 deg.C and kept for 1-5hr. Then, after slow cooling to room temperature (point B), the material is aged by heating to 820-860 deg.C and keeping for 10-30hr. No cracking due to deposition of carbide occurs in the weld zone, and welding of Ni base sintered hard alloy heat resisting steel can be put to practical use.

Floating zone melting process

Abstract: 1. Process for the non-crucible zone melting of a silicon rod which is supported at its ends, in which an induction heating coil which surrounds the rod in annular fashion and which produces a molten zone in the rod is moved relative to the rod in the axial direction thereof within a container which contains a predetermined gas mixture consisting of oxygen and a shielding gas, the partial pressure of the oxygen being maintained at a value which is at least equal to the vapour pressure of the silicon at the melting temperature, characterised in that the gas mixture is fed to the molten zone as a flowing gas ; that the speed of the gas mixture is selected to be directly proportional to the vapour pressure sent in the container (5) ; and that the flow rate of the gas mixture is so selected that reaction products produced are carried away from the region of the molten zone.

Pulsed direct current arc welding

Abstract: A method of arc welding is disclosed. Specifically, a method of pulsed direct current (DC) arc welding is disclosed wherein special pulses of positive direct current are used to weld together work pieces. The special DC pulses are capable of dissipating difficult to reduce oxides which may be present on the surfaces of the work pieces without using a flux. The method is especially useful for fluxless arc welding of aluminum, particularly thin wall aluminum tubing used in making heat exchangers for air conditioning systems.

Automatic welding equipment of pipe and tube plate

Abstract: PURPOSE:To prevent shielding gas from flowing out and a W electrode from being oxidized and burned by mounting a flange-shaped jig for preventing the flow-out of shielding gas on the pipe end side of a sleeve-shaped jig for tracing pipe inside diameter at the time of joining a pipe body into the insertion hole of a tube plate by automatic TIG welding CONSTITUTION:A flange part 8 for hermetically sealing a pipe hole by abutting its end edge to a tube plate 2 is provided to the pipe end side of a welding torch 6 which functions as a sleeve-shaped jig for tracing pipe inside diameter The axial size (a) of the flange part 8 is so adjusted that a predetermined welding position is automatically set in a W electrode 3 The welding torch 6 mounted with the flange part 8 is inserted into a pipe 1 until the leading end of the flange part 8 contacts the tube plate surface to prevent the shielding gas such as Ar led into between the welding torch 6 and an electrode holder 4 from flowing to the outside at the welding and hermetically seal the weld zone The welding work is performed in the atmosphere substituted completely by the shielding gas, whereby the W electrode is prevented from being oxidized and burned

Shielding device for multiple-electrode gas shielded consumable electrode type arc welding

Abstract: PURPOSE:To maintain good gas shielding condition in titled welding and improve quality of weld zone by arranging properly side walls and a partition wall consisting of a main nozzle for main shield gas, a subsidiary nozzle for after shield gas, and water cooling walls made of copper. CONSTITUTION:A main nozzle for main shield gas 11 supplies main shield gas 12 from the front of a torch 9 of direction D of progress of welding to the torch 9. Gas 12 shields the circumference of an arc 14 to stabilize the arc 14 and shelter molten metal 15 from atmosphere without dispersing in the direction perpendicular to the direction of welding being intercepted by side walls 13 built parallel to the direction of welding on the side of the torch 9. After shield gas 17 supplied from the subsidiary nozzle 16 fills up a cover box 18, and shelters the metal 15 and high temperature metal 19 just after solidification from atmosphere. A partition wall 20 is provided to prevent collision and interference of gas 12 and gas 17. The side walls 13 and the partition wall 20 are made of copper to enable continual use as water cooling walls.

Metal strip welding method

Abstract: PURPOSE:To contrive reduction of down time of welding process and to improve welding accuracy simultaneously, by performing the strip cutting, welding, and heat treatment in the metal strip welding process in one stage with the laser beam. CONSTITUTION:A required amount of rear end of preceding strip 12a and the front end of succeeding strip 12b (the strip is called as board hereinafter) are lapped to each other, and they are fixed with double clamp 13. Then head 10 for laser working is moved along the direction perpendicular to the surface of paper, and boards 12a and 12b are piled up and cut by irradiating beam 11. After removing unnecessary materials and raising clamp 13a by the height equal to the thickness of board 12b, clamps 13b and 13a are moved for a minute distance forward and backward along the advancing direction of board, and an I-shaped beveling butt joint of 0mm. root gap is formed. This part is welded by running beam 11. Then, head 10 is raised and is made run by avoiding the focal point of beam 11 from the surface of boards 12a and 12b, and the welding part is softened. Moreover, oxygen 16 and shield gas 19 are supplied when the cutting and welding are performed, respectively.