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

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.

Chromium and nickel aerosols in stainless steel manufacturing, grinding and welding

Abstract: Composition, morphology and solubility of chromium and nickel in fumes from stainless steel manufacturing, based on ferrochrome, and in dusts from grinding of stainless steel, were studied. The results were compared with corresponding analyses of stainless steel welding fumes. In fumes from the melting of ferrochrome and stainless steel, as well as in dusts from the grinding of stainless steel, chromium is only slightly oxidized to the hexavalent state. Therefore, chromates are present in very low concentrations in contrast to manual metal arc welding fumes where chromium is oxidized to CrO3 and reacts with alkali oxides (K2O, CaO) to form respective chromates. Nickel occurs in fumes from stainless steel manufacturing mainly as metallic alloyed element in the iron matrix or in small amounts as oxide (NiO). In stainless steel welding fumes, separate nickel oxide particles have been found. Airborne particles originating from the melt are typically round and possibly covered by a slag layer.

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.

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.

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.

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.

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.

Deep penetration arc welding method for thick walled steel materials by multiple electrodes

Abstract: PURPOSE:To control the component compsns of weld metal and to prevent the generation of microcracks by penetrating a component-controlled ingot block which is interposed within the root surfaces in the groove of a welded joint deep by welding under the conditions of burying the arc CONSTITUTION:In submerged or gas shielded arc welding of multiple electrodes, for example, in the former, an insert 5 of a steel block 5 is held in place between the butt surfaces of steel plates 1, 1' to be welded The arc is generated between a wire 7 and the insert 5 in the flux to melt the insert partially, whereby molten metal 3 is formed After this, the plates 1, 1' are turned over to weld the opposite side similarly and to melt the unmolten insert 5 fully, and this completes the welding of the plates 1, 1' The dependency of the compsn of the metal 3 upon the plates 1, 1' is reduced by this; therefore, the metal 3 of high cracking resistance is formed by controlling the components of the insert 5

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.

Apparatus for electric arc welding

Abstract: The invention relates to an apparatus for electric arc welding of two anschmelzender workpieces, preferably pipe ends, rings od Like On a closed seam path, in which at least two radially disposed in the welding plane, the same pole magnets 1 by a surrounding the weld path magnetic ring are combined In order to increase the field strength at such magnet assemblies, the invention provides that the weld path surrounding ring is formed by the weld path of the facing ends of the magnets Resistances which would otherwise occur with a separate, associated with the magnet ring, are thereby eliminated

Evaluation of shielded metal arc and flux cored metal arc welding consumables for fabrication of stainless steel magnet cases for 4K service

Abstract: Of three highly restrained SMA welds made in the flat-position with large diameter Type E316L-15 welding-electrodes supplied by different vendors, two welds showed adequate combinations of 4K tensile and K/sub IC/ properties to be considered for use in manufacture of MFTF-B superconducting magnet-cases. The poor 4K performance of the third SMA weld is explainable, in part, by a combination of higher ferrite level and N/sub 2/ concentration than in the other two SMA welds. Despite presence of undissolved metallic flux-constituents and porosity in a Type 316L FCMA weld, its 4K K/sub IC/ would be adequate for use on Mirror Fusion Test Facility (MFTF-B). However, its 4K sigmay was slightly below MFTF-B requirements.

Method for the arc cutting of metal

Abstract: Disclosed is an improved method for arc cutting of metal, more specifically a method in which an electric arc is formed between the metal and a cutting torch and gas is blown into the cut during the cutting process. According to the invention a paste is injected through the torch into the region of the arc, said paste containing a finely-divided electrically conducting substance mixed with a carrier and acting as an electrode which causes the electric arc to be struck. The conducting substance may contain e.g. metal powder, such as powder of aluminium or of an aluminium alloy, to which also carbon and phosphorus may be added.

Flux cored wire for arc welding

Abstract: PURPOSE:To form weld beads having excellent shapes, appearance, undercut resistance and releasability of slag in the stage of flat fillet welding and horizontal fillet welding by using a flux cored welding wire electrode contg. TiO2, SiO2, Al2O3, Mn and org. materials as essential components. CONSTITUTION:In the stage of flat fillet welding and horizontal fillet welding, a welding wire wherein a flux contg. 35-70wt% TiO2, 5-30wt% SiO2, 1-5wt% Al2O3, 10-30wt% Mn, and 0.2-6wt% org. materials such as pulp flocs, starch, guar gum as essential components and further contg. 0.5-15wt% in total >=1 kind among CaO, MnO, and MgO in order to improve releasability of slag is packed at 10-25wt% based on the weight of the wire in a mild steel sheath is used. Even in the flat position in the fillet joint parts of a relatively wide gap larger than 3mm. and in horizontal welding, no undercuts are produced and the weld beads having excellent appearance are formed.

Method of build up welding of member having cylindrical surface and apparatus for executing the same

Abstract: An electro slag welding process for a cylindrical member such as an iron roll for a steel mill. The purposes of this invention are to solve the problems of (1) what type of electrode should be used to supply the large current to the slag, and (2) how to prevent the tendency of the depth of penetration of the weld into the base metal to increase excessively due to an increased melting of the base metal resulting from increasing the build-up depth, and thus to increase the welding heat supplied, and to decrease the rising speed of the melt (i.e. the welding speed). In this process a plurality of large consumable bar electrodes (12) supply polyphase AC current to the slag; and the base metal (10) and pad (16) are rotated while continuously adding molten metal (13) to the surface of the slag bath (14). This may be utilized for producing and repairing a cylindrical composite member.

Submerged arc welding in inert gas - so weld deposits with high notch impact toughness can be obtd.

Abstract: During submerged arc welding, the powder is covered by a hood filled with inert gas; and the height of the welding powder is 4-5 times the electrode dia. Immediately after the weld deposit has solidified, the slag is removed while it is still molten. The molten slag is pref. removed by brushing. With conventional submerged arc welding, the notch impact toughness (NIT) of the weld deposit is lower than the NIT of the workpieces, one of the causes being the poor temp. control resulting from a powder height of 8-10 times the electrode dia. The invention uses a lower powder height and inert gas so the cooling rate of the weld is increased but not pores are formed in the deposit. Rapid slag removal also increases the cooling rate and further improves the NIT of the deposit.

Method for generating arc in gas shielded metal arc welding

Abstract: PURPOSE:To prevent occurrence of large sized sputters and to improve the operating efficiency, by generating the arc through applying a high frequency high voltage across the base material and wire without contacting the base material with the wire. CONSTITUTION:Welding machine 1, high frequency screening circuit 2, arc generation detecting circuit 3 and high frequency generating circuit 4 are connected in series, and the switch is on to generate the high frequency. The high frequency generates the arc between torch 6 and base material 7 via coupling coil 5 in such state that the arc does not contact between the torch 6 and base material 7. Arc generation detecting circuit 3 detects no-load voltage applied across wire 8 and base material 7, and send the signal of ''In'' to high frequency generating circuit 4, and, when load voltage is applied across wire 8 and base material 7 due to the arc generation, the power source of high frequency generating circuit 4 is turned off and the circuit 3 operates as a normal gas shielded metal arc welding machine. High frequency screening circuit 2 obstructs and absorbs the high frequency inversely flowing to the power source with the coil and condenser, collecting and annihilating the high frequency.

Welding process and electrode therefor.

Abstract: A manual metal arc process for depositing weld metal on a cast iron workpiece is accomplished by using a welding electrode having a cast iron core with a coating of limestone and ferro-silicon. The proportions of limestone and ferrosilicon in the coating are selected so as to give a carbon equivalent value in the deposited weld metal substantially equal to the carbon equivalent value in the workpiece als calculated from the formula t

Continuous submerged arc welding, esp. of steel plates - using one or more consumable electrode wires, and also metal filler powder supplied without electric current

Abstract: During the welding process, an additional filler material is added in the form of granular or powdered metal, which is not supplied with electric current, but which is fed into the molten welding powder covering the weld pool near the roof of the arc cavity. The additional filler is pref. supplied by a tube located in the welding powder. When the additional filler consists of magnetic powder, it is pref. added by one or more tubes which have their bottom, outlet ends above the layer of welding powder in which the arc is submerged. Another alternative feeder for the granular or powdered filler metal is a ring outlet nozzle surrounding a consumable electrode wire. A further 150% of filler metal can be added in addn. to the filler metal obtd. from the consumable electrodes, so welding speeds can be increased without a significant increase in energy consumption; and the quality of the welds is improved.

Acoustic Emission from Structural Steels and Weldments

Abstract: Acoustic emission (AE) burst signals generated by deformation and fracture processes associated with crack growth under monotonic loading have been measured during tests of notched specimens and medium-sized pressure vessels under various testing conditions. A mild C–Mn steel and a Nb-microalloyed and Al-treated C–Mn steel, both normalized, were studied. Weld metals were produced by submerged arc welding, manual metal arc welding, and metal active gas welding. A single-channel AE monitoring system was applied, with attention paid to burst signals sufficiently large to be used during surveillance. The two base metals generated only a small amount of AE burst signals under all testing conditions whereas the number of burst signals generated by some of the weld metals was considerably larger. The number of burst signals increased when the temperature decreased into the toughness transition temperature region. The AE activity of the noisy weld metal during fracture seems associated with a particular f...

Weldin g processe s an d ocula r hazards an d protection

Abstract: There are approximately 60 different forms of welding, but only six of these are commonly used. Shielded metal-arc or stick weld­ ing, gas metal-arc welding, and oxyacetylene welding are the most frequently used. All produce ultraviolet, visible, and infrared radiation at damaging levels. Conventional glass welding shields contain ultraviolet, visible, and infrared absorbers. Infrared ab­ sorbers, however, cause heating and secondary re-radiation. New polycarbonate lenses offer greater impact resistance, and have less tendency to welding spatter. Early abrasion-resistant and reflective coatings on plastics were ineffective. Thin layers of gold with proprietary coatings provide cool reflection and surface resistance. Thermal monitoring of welding indicated that these new shields reduce temperature rises above the ambient by 150% to 175% compared to green glass filter plates without interfering with the welder's vision.