Showing papers on "Shielding gas published in 1978"

Production of glass base material for light transmission

Abstract: PURPOSE:To obtain the title material with little light absorption loss by forming a laminar deposit of glass fine particles by flame hydrolysis after which the deposit is heated in a fluorine cpd. gas atmosphere and sintered in an inert gas atmosphere to reduce the OH group concn. of the glass. CONSTITUTION:Oxygen 2, hydrogen 3, shielding gas 4 and feed gas 5 are fed into coaxial multiple tube burner 1 made of quartz to deposit glass fine particles on the outside of rotating starting material 6 by flame hydrolysis. The resulting laminar deposit of glass fine particles is introduced into a high temp. furnace provided with many gas introduction openings 8 in the inner wall. In the furnace the deposit is heated to 1000 deg.C or below while supplying a fluorine cpd. gas such as fluorocarbon gas or sulfur fluoride gas from gas supply inlet 9 to obtain a glass fine particle body whose outer circumference portion contains much fluorine. This body is then put into high temp. furnace 10 of an inert gas atmosphere and sintered at 1400 deg.C or above to convert it into transparent glass.

Active gas plasma arc torch and a method of operating the same

Abstract: An active gas plasma arc torch and a method of operating the same, said torch including a rod-shaped cathode, a first gas passage formed around said cathode to feed a protecting gas or shielding gas, a second gas passage formed around said first gas passage to feed a plasma gas and a constricted port for discharging the plasma gas, characterized in that at least a part of the shielding gas which flows out from the first gas passage is removed from the inside of the torch at the position short of said constricted port of the torch, whereby the working quality and the working speed are substantially improved while the rod-shaped cathode is satisfactorily protected by the shielding gas.

Method of cold welding using ion beam technology

Abstract: A method for cold welding metal joints. In order to remove the contamination layer on the surface of the metal, an ion beam generator is used in a vacuum environment. A gas, such as xenon or argon, is ionized and accelerated toward the metal surface. The beam of gas effectively sputters away the surface oxides and contamination layer so that clean underlying metal is exposed in the area to be welded. The use of this method allows cold welding with minimal deformation. Both similar and dissimilar metals can be cold welded with this method.

Welding process for production of a steel pipe

Abstract: Disclosed herein is an improvement of a welding process for welding a steel pipe, wherein a gas metal arc welding is performed to form the first welding layer and a submerged arc welding is performed to form the last welding layer. According to the conventional gas metal arc welding process, i.e. the MIG or CO2 welding processes, the combined use of a high welding current and a welding wire having a small diameter is known to bring about the rotation of the welding arc and the formation of an undercut along the toe of the weld metal. The purpose of the present invention is to weld a steel pipe having either a large thickness or an excellent ductility at a temperature of less than -40° C., or both. According to the present invention, the combined use of a high welding current and a wire having a small diameter is possible, by employing a gas mixture containing an inert gas as a major part thereof and CO2 as an additional part thereof as a shielding gas. In addition, by adequately selecting the wire extension, the gas metal arc welding is improved to provide the features of: deep and round penetration; stable arc formation with stiffness of the arc, and; high metal deposition rate.

Gas-shielded flux-cored wire electrodes for high impact weldments

Abstract: A cored wire electrode for use with a shielding gas, particularly in out-of-position welding, said electrode having a core material containing rutile, an arc stabilizer, deoxidizers including from about 5 to 15 weight percent of a manganese and silicon-containing compound, from about 1 to about 7 weight percent of magnesium and/or magnesium-aluminum alloys, from about 3 to about 10 weight percent manganese oxide, from about 5 to 20 weight percent nickel, from about 2 to 15 weight percent silica, and from about 05 to 50 weight percent A1203-Si02-K20 SPECIFICATION

Gas Tungsten Arc Welding

Abstract: Gas tungsten arc welding (GTAW), also known as tungsten inert gas (TIG) welding, is an arc welding process that uses a nonconsumable tungsten electrode to produce the weld. The weld area is protected from atmospheric contamination by a shielding gas (usually an inert gas such as argon), and a filler metal is normally used, though some welds, known as autogenous welds, do not require it. A constant-current welding power supply produces energy which is conducted across the arc through a column of highly ionized gas and metal vapors known as a plasma.

Oxygen and Nitrogen Contamination during Arc Welding.

Abstract: : The sources, mechanisms, and expected levels of oxygen and nitrogen contamination during gas tungsten arc, gas metal arc, shielded metal arc, self-shielded metal arc, and submerged arc welding are reviewed. Calculations indicating the importance of decomposition of SiO2 into silicon monoxide and oxygen are presented, indicating that silicon transfer between the slag and metal occurs by a gas-metal rather than a slag-metal reaction mechanism. A model suggesting that arc stabilizing additions to fluxes should provide volatile subspecies upon heating is also discussed. (Author)

Surface hardening build-up welding method

Abstract: PURPOSE: To form weld metal of higher hardness than before and free from production of weld cracks by supplying the mixed powder comprising adding powder of one or more kinds of NbC and VC to alloy steel powder containing Fe and Cr into the arc generated between the iron or steel base metal shielded with inert gas and a non-consumable electrode. CONSTITUTION: While Ar gas is being supplied to a shielding gas nozzle 4, a DC arc is generated between the carbon steel base metal 1 to be welded and a tungsten electrode 2 from a power source 7. In this state, Ar gas is supplied to a powder hopper 8 to let the mixed metal powder to fall into the arc, thereby letting weld metal form on the surface of the base metal 1 while letting the powder melt. The powder mixture comprising adding one or more kinds of NbC powder, VC powder, TiC powder at ratios of 35 to 85vol% to the alloy steel powder composed primarily of Fe, Ni, Cr or Fe, Cr is used as the mixed metal powder of this case. The Vickers hardness of the weld metal by this method becomes 900 to 1000 but production of cracks in the weld zone will not occur and penetration of the base metal to be welded does not occur at all. COPYRIGHT: (C)1980,JPO&Japio

Method for electroslag welding of metals

Abstract: A method for electroslag welding of metals whose density is less than thatf welding fluxes, is provided. The method is based on floating-up of drops of molten metal of the edges being welded and of the electrode in a slag whose density exceeds that of the metal. The floating-up metal drops form a metal bath on the surface of the slag bath, and crystallization of the metal bath produces a weld. In the course of welding, the electrode metal is fed into the slag bath in the upward direction, while the electrode metal melts and the weld is built up in the downward direction.

Method and device for welding in a thermally ionized gas

Abstract: A plasma-MIG welding system in which the power for establishing the MIG-arc is supplied to the consumable electrode at a point downstream of the non-consumable electrode.

Inconel welding method of dissimilar material joint

Abstract: PURPOSE: To improve the strength of weld zone and welding efficiency by controlling the temperature of weld pass through water cooling at the time of Inconel welding the dissimilar material joints of austenite base stainless steel and ferrite steel. CONSTITUTION: A weld torch nozzle 1 and electrode 3 are disposed in the joint part and an Inconel welding material 6 is welded by generating arc between the joint part and electrode while blowing Ar gas 2. At this time, cooling water 9 is sprayed through the water injection holes 8 of a water supply pipe 7 disposed on the side opposite from the torch nozzle in the entire stage or part of the stage of the welding work to water cool the weld zone and weld side end part of the austenite base stainless steel 4. Thereby, the thermal stress affecting the low alloy steel material 5 such as of Cr-Mo steel or other may be eliminated and cracking and degradation of material quality may be prevented. COPYRIGHT: (C)1980,JPO&Japio

Dual-gas shielding method

Abstract: The disclosure of the present application relates to an improved method of open-arc welding. According to the present method, the outer shield of a double-shield welding system consists of a stream of gas formed in a shield concentric with the inner shield. This method is distinguished by the fact that atmospheric air may be used as the outer shield gas because the outer-shield velocity is so regulated and so positioned as to prevent the air from being drawn into the weld area, the outer shield gas velocity nearly approximating the inner shield gas velocity.

Solid wire for gas shielded arc welding and production thereof

Abstract: PURPOSE: To obtain a defectless deposited metal by holding and sticking a specified amt. of an oily lubricating oil contg. potash soap or soda soap on a wire surface, thereby preventing the adhesion of the deposits of an antifriction compsn. or the like which exert adverse influence on the deposited metal. CONSTITUTION: The oily lubricating oil contg. the potash soap or soda soap is held and stuck at 0.2 to 10g per 10kg wire on the surface of the wire for a gas shielded arc welding to be used at the time of executing the arc welding while automatically supplying the wire in a shielding gas atmosphere. As a result, the deposits of the antifriction compsn. or the like which exert adverse influence on the deposited metal are not stuck to the wire surface and, therefore, the deflectless deposited metal is obtd. Since the metal having a low potential gradient can be uniformly stuck to the wire surface, good wire stability is obtd. Further, the oily lubricating oil can be uniformly stuck to the wire surface and, therefore, the good wire feedability and wire rust preventiveness are obtd. COPYRIGHT: (C)1990,JPO&Japio

Welding method for forming thick walled steel pipe

Abstract: PURPOSE: to obtain high quality weld zone excellent in the low temperature toughness at high efficiency, by employing the thin wire with the high current at welding the thick walled steel pipe, by preparing the mixed gas atmosphere from the inert gas added with CO 2 , and by giving a fast fine oscillation to the arc. CONSTITUTION: At welding work for forming the thick walled steel pipe, by first executing the MIG welding for the root layer and then by executing the SAW welding for obtaining the flush weld as the final layer; the mixed shielding gas atmosphere is prepared by adding CO 2 to the main mass of the inert gas, and the thin welding wire of diameter 0.8W2.4mm is employed. The distance l(mm) between the feeding tip and the groove bottom is set at l>10d+5, and the welding current I is set against the wire diameter (d) at the range, 500d≥I≥500d-150. Furthermore, a fast oscillation of frequency 3W30 cycle/sec and amplitude 1W15mm is given to the arc. Hereby, the arc is generated in the state of being throttled to thin and stiffened, the resistance against the magnetic blowout is improved, the directivity of the arc in the direction of wire extension is improved, and the smooth appearance of beads is obtained. COPYRIGHT: (C)1980,JPO&Japio

Arc modeling for welding analysis

Abstract: A one-dimensional model of the welding arc that considers heat generation by the Joule effect and heat losses by radiation and conduction has been used to study the effects of various gases and gas mixtures currently employed for welding applications. Minor additions of low ionization potential impurities to these gases are shown to significantly perturb the electrical properties of the parent gas causing gross changes in the radial temperature distribution of the arc discharge. Such changes are reflected in the current density distribution and ultimately in the input energy distribution to the weldment. The result is observed as a variation in weld penetration. Recently published experiments and analyses of welding arcs are also evaluated and shown to contain erroneous data and results. Contrary to previous beliefs, the inclusion of a radiation loss term in the basic energy balance equation is important and cannot be considered as negligible in an argon arc at temperatures as low as 10,000/sup 0/K. The one-dimensional analysis of the welding arc as well as the evaluation of these earlier published reports helps to explain the effects of various gases used for welding, improves our understanding of the physics of the welding arc, and provides a steppingmore » stone for a more elaborate model which can be applied to help optimize welding parameters.« less

Tandem system high speed arc welding method

Abstract: PURPOSE:To form an excellent weld bead at high speed, by melting and smoothing the bead surface layer by TIG welding after forming a bead on the steel plate by MIG welding in a shielding gas containing O2 and H2 by specified contents in Ar. CONSTITUTION:While feeding Ar containing O2 by 0.2-2wt% and H2 by 0.4- 4% from a gas feed hole 4 in a trailer shield nozzle 3 as shielding gas, non-oxidation weld bead 7 is formed on a steel plate by means of a MIG welding torch 1 having an electrode wire 2. A TIG welding torch 5 which is connected to said torch 1 in a position behind the same MIG welding torch 1 and has W electrode 6 is moved to the left at high speed, and the surface layer of the non-oxidation weld bead 7 is melted and smoothed by the torch 5. In this method, high-speed welding may be performed stably, and an excellent weld bead free of undercut may be easily obtained.

Steel welding method

Abstract: PURPOSE:To weld a steel material to be welded by a welding material having a strength lower than the strength of said steel undergoing restraint by welding, to cool the same, and thereafter to heat the welded part and to subject the welded parts to aging thereby to increase the strength of the soft welding joint more than the strength of the material to be welded. CONSTITUTION:A steel material to be welded such as a structure steel or the like is welded by a welding material having a strength lower than that of the steel material. In this case, welding is carried out preferably by use of a shield gas prepared by mixing 0.2 to 5% by volume of a nitrogen gas into a gas consisting more than a member selected from the group consisting of argon, helium and a carbonic acid gas. Then, the welded steel is cooled, and thereafter the welded part is heated and held at a temperature in the range of from 200 to 300 deg.C and then subjected to aging.

Consumable welding electrode

Abstract: A consumable welding electrode, a method of electroslag welding using such an electrode, and an electroslag weld deposit produced by the use of the welding electrode and welding method of the invention. The welding electrode, while not restricted thereto, has particular utility for use in the electroslag welding of high tensile strength members formed of low alloy steels of the family of steels which includes American Society of Testing Materials designation ASTM A516-76. The welding electrode has a chemical composition in which the carbon content and contaminants have been reduced to the very minimum possible, resulting in greater impact strength of the electroslag weld deposit. The welding electrode includes constituents of manganese, silicon, nickel and iron. The nickel and manganese content of the electrode are so proportioned as to compensate for loss of tensile strength in the electroslag weld deposit which would otherwise be caused by the minimal carbon content of the welding electrode, this proportioning of the nickel and manganese content of the welding electrode also maximizing impact strength and ductility of the weld deposit. When the electrode of the invention is used for the electroslag welding of low alloy, high tensile strength steel members, such as steels of the ASTM A516-76 family, the resulting electroslag weld deposit has a characteristic microstructure resulting in good tensile strength, high impact strength, and good ductility characteristics over a wide range of dilution of the weld deposit by the base metal, all without the necessity of an expensive and energy-consuming post-weld "normalizing" heat treatment as has been required in the prior art.

High current density gas shielded vertical welding method

Abstract: PURPOSE: To obtain the weld zone of superior low temperature toughness with high efficiency by performing welding under the specific conditions for the groove provided to thick steel materials such as double shell tanks or the like for LPG storage by the use of CO 2 or Ar+CO 2 and the use of a small-diameter composite wire of a limited sectional area combining flux and iron powder. CONSTITUTION: The groove of the specified shape is made based on the quantity of welding heat input to steel materials of 6W38mm plate thicknesses such as of double shell tanks or the like for storing LPG of boiling points 0W50°C. Next, welding is done in 1W2 passes according to plate thicknesses to this groove, by using CO 2 or Ar+CO 2 as shielding gas and under the following conditions. Namely, welding is done at welding current densities 220W370A/mm 2 and quantity of heat input 20W50KJ/cm by using the composite wire of 1.2W2mmϕ whose sectional area of the combined flux and iron powder occupies 30W35% based on the total sectional area of the wire. COPYRIGHT: (C)1980,JPO&Japio

Submerged Arc Welding of Titanium.

Abstract: : The submerged arc welding of titanium using CaF2 fluxes has been studied to determine the sources of nitrogen contamination and the effect of flux purity on arc stability and weld bead shape. It is shown that plasma jet entrainment and atmospheric absorption on the hot base plate ahead of the arc prior to flux melting are the primary sources of nitrogen contamination. The arc stability is strongly dependent upon the CaF2 purity. The high weld bead contact angle is a result of the metal transfer mode of the consumable titanium electrode. In addition, the effect of CaF2 flux on gas tungsten arc welds has been briefly studied, indicating enhanced weld penetration in the presence of a flux. A critical review of available information on Soviet titanium fluxes is also presented. (Author)

Non-return devices for welding installations

Abstract: A non-return device for welding installations, of the kind comprising a movable valve arranged so as to free the passage of gas for the normal supply of the torch from a welding gas generator and, by contrast, to block said passage in the case of a back-pressure resulting from an explosion in the region of the torch burner, the said valve including for this purpose closure means co-operating with a seat under the effect of resilient return means, the valve including second closure means operating inversely to the first in such a manner that the displacement of said valve, under the effect of a sudden fall in pressure downstream of the device and against return means conveniently calibrated to this effect, ensures the automatic cut-off of the flow of gas through the assembly.

Fatigue Crack Propagation in A537M Steel

Abstract: Fatigue crack propagation rates are presented for weldments in A537M steel at room temperature. Rates are determined for cracks propagating along the fusion line, in the melt zone of welds made with two shielding gas ratios, and in the base metal. Static tension and Charpy impact tests conducted on specimens from the base material and melt zone also are presented. Results indicate that crack growth resistance of A537M steel is not degraded by proper welding procedures, and the weld zone may impede growth rates. Shielding gas ratios, which affect tensile properties, are shown not to affect fatigue crack growth rates significantly. An interim da/dN versus ΔK design curve is computed for the data sets, and its application to flawed plate life prediction is discussed.

Method of controlling heat source of reverse-polarity plasma arc

Abstract: PURPOSE: To control the energy density of a plasma arc by properly adjusting the amount of oxygen in the shield gas and by controlling the cleaning width arbitrarily. CONSTITUTION: In a device in which plasma arc 4 from reverse-polarity plasma-arc generating device 1 is ejected on base material 3, shield gas 14 is supplied from the neighborhood of electrode 11, and thus cleaning width 5 is formed. By controlling the amount of oxygen in the shield gas suitable at this time, the cleaning width is adjusted arbitrarily. COPYRIGHT: (C)1979,JPO&Japio

Flux-cored electrode for welding steels in carbon dioxide

Abstract: A flux-cored electrode intended for arc welding of steels in carbon dioxides characterized in having a casing of a low-carbon steel filled with a powder flux containing (in weight percent): calcined magnesite: 4-8, feldspar: 6-9, calcium fluoride: 4-5.5, titanium dioxide: 14-20, ferromanganese: 6-10, ferrosilicon: 1.5-3, iron powder: the rest. The flux-cored electrode is practicable if used in semi-automatic and automatic welding of metal structures from structural low-carbon and low-alloy steels and from steels of improved strength. The flux-cored electrode with the above chemical composition of the flux is conducive to reduced separation of fluoride gases harmful to welders, the high welding characteristics of the electrode remaining intact.

Glow-discharge electron beams for pipe welding

Abstract: As an alternative to conventional argon arc and vacuum electron-beam welding, the glow-discharge electron beam offers several advantages, particularly for welding pipes.

Gas shield method in laser welding

Abstract: PURPOSE:To provide the subject method comprising shielding the back bead formed part at the welded section by a high-pressure shield gas, and swinging a laser beam in a direction rectangularly intercrossing the weld line to carry out laser welding, whereby an excellent weld bead is formed and welding efficiency is improved.