Showing papers on "Heat-affected zone published in 1976"

Process for reducing stress corrosion in a weld by applying an overlay weld

Abstract: The stress corrosion tendency of a welded pipe in service in a nuclear reactor water line is reduced by applying to the outside of the pipe a secondary weld bridging the primary weld of the joint beyond the axial extremities of the primary weld heat affected zone and particularly that part of the zone at the inner surface of the pipe.

Arc welding process

Abstract: An arc welding process having a welding arc generated between a consumable electrode and the materials to be welded and a welding torch is oscillated along the welding joint line, wherein the arc length is longer when the welding torch is located at the forward side of the oscillation than when the welding torch is located at the backward side of the oscillation with respect to the weld advancing direction, whereby sufficient penetration is obtained.

Welding flux formulation and process for fume reduction

Abstract: The invention is concerned with a welding flux composition comprising a first alloy including iron, at least two metals reactive with oxygen under welding conditions and selected from the group consisting of aluminum, titanium, zirconium and boron and a weld improving metal selected from the group consisting of magnesium and manganese, said first alloy comprising from about 1 percent to about 4.5 percent by weight of the flux composition. The invention is also concerned with a weld forming composition comprising a metal tube having therewithin a welding flux as set out above. The invention is further concerned with a process for reducing particulate matter produced during the welding operation, comprising a welding flux used in said operation including from about 1 percent to about 4.5 percent by weight of the above first alloy.

Fused flux for submerged arc welding

Abstract: PURPOSE:To form weld metal having high toughness without degrading the refiring characteristics of arcs by controlling the compsn of a fused flux for submerged arc welding adequately and coarsening the grain sizes thereof CONSTITUTION:In order to decrease the content of oxygen in weld metal and to improve toughness in submerged arc welding, the partial pressure of gaseous F in an arc atmosphere is increased by contg CaF2 in the flux used whereby containing of O2 in weld metal is prevented The flux to be used for said purpose is formulated to contain 5-25% SiO2, 05-15% MnO, 5-25% CaO, 5- 20% MgO, 2-20% Al2O3, 2-10% TiO2, 1-5% BaO, 20-60% CaF2, to contain 01-15% B2O3 if necessary, and to contain (CaO+MgO)/SiO2 at 15-30 ratio Such flux is used at grain sizes coarser than 200 meshes specified in ASTM Welding is accomplished with the stable arcs without degrading the refiring characteristics of the arcs owing to an increase in the content of CaF2

Review of the present state-of-the-art in explosive welding

Abstract: A brief review of the history and simplified mechanism of explosive welding is presented. Consideration is then given to the present state of understanding of the parameters which control the explosive-welding process, and the implications of these parameters in relation to thin- and thick-plate cladding. The problem of cladding large thick plate is then considered and experimental data are reported which support the welding parameters proposed, and which allow definite conclusions to be drawn of the set-up required to achieve welding over the whole plate and close to the edges of the parent plate. Applications of explosive welding to cylindrical surfaces are reported including tube-to-tube welding, plugging of heat exchangers, welding of collars to tubes, etc. In particular, the problem of ligament distortion in tube-to-tubeplate welding and plugging is considered. The alternative possibility of placing bungs in the holes adjoining that in which a tube is being welded is examined. Other applicati...

Inert gas welding

Abstract: Welding apparatus for inert gas shielded arc welding comprising a welding gun for holding and controlling a non-consumable electrode and including means for supplying inert gas to the welding arc region by way of a gas cup surrounding but spaced from such an electrode when positioned in the gun, the welding gun being further provided with an extended gas shielding wall arrangement protruding a substantial distance beyond the gas cup and capable, either by itself or in combination with a narrow gap weld preparation, of substantially enclosing an electrode in the gun, except for its tip, when the electrode is protruding for a similar distance beyond the gas cup.

Laser Welding of Dissimilar Metals: Titanium to Nickel Metallurgical study shows why Ti to Ni joints were un­ successful by laser welding

Abstract: Laser welding is sometimes used to weld dissimilar metals when other methods prove unsat isfactory. A number of such cases have been reported in the literature and are listed in Table 1. However, the welding of these pairs of metals was usually done in response to a specific engineering need, and very little has been reported on the relationship between the welding variables, the propert ies of the weldment , and metallurgical structure. No systematic studies of laser welding of dissimilar metals have apparent ly been attempted yet. The present investigation was initiated with the intent of metal lurgical ly character iz ing d issimilar metal welds.

Vertical welding method

Abstract: The present invention relates to a method of vertically upward arc welding for vertical and inclined joints. More particularly, the invention relates to a vertically upward arc welding method which includes the step of feeding a strip electrode in a direction at which the plane including the width direction of the strip electrode crosses the weld line, generating an arc from the strip electrode to a molten pool and/or an upper base metal disposed above the surface of the molten pool, melting the upper base metal disposed above a sliding backing shoe on the front surface side of the groove, and performing welding by expanding the groove and simultaneously dropping the molten metal onto the lower molten pool and depositing the same therein.

New process combines plasma with gma welding

Abstract: A process of gas metal-arc welding in a thermally ionized gas is described in which the filler metal is fed along the axis of a plasma stream to the workpiece Two of the most important electrode arrangements that can be employed with this process are discussed The electrical properties and the flexibility of gas metal-arc and plasma-GMA welding are compared Data on deposition rate, welding, speed, penetration and wetting-in are determined Finally, a number of possible applications and some already achieved are described

Overhead submerged arc welding process

Abstract: The present disclosure relates to an overhead submerged arc welding process wherein a flux for the submerged arc welding is supplied from the underside of the welding line while at the same time a consumable electrode is supplied from the underside of the welding line, the process being characterized by maintaining the interrelationship between a flux supply cylinder and the plates to be welded such that the length from the under surfaces of the plates to be welded to the upper end of the open flux supply cylinder and the diameter D of the opening at the end of the flux supply cylinder is represented by the formula 2≦D/I≦15.

Hydrogen cracking in weld metals

Abstract: The crack susceptibility of a wide range of weld metals deposited by various processes was examined. The degree of cracking increased with increasing alloy content and hydrogen level. Weld metals with higher alloy level were not affected as much by changes in hydrogen content as lower alloy weld metals. The results have been analyzed on the basis of a simple model where it is assumed that the sole effect of preheat is in allowing hydrogen to diffuse from the weld before it cools to below 50 C. From the measured cooling history of preheated gapped bead-on-plate tests a diffusion parameter is calculated. Decay of hydrogen content is assumed to be exponential, and an equation relating the diffusion parameter to the composition and hydrogen content is established with the constants determined from the experimental results. Good agreement exists between the final equation and experiment and is independent of the welding process when the hydrogen is expressed in terms of fused metal rather than deposited metal.

Electrical contact element and method of producing the same

Abstract: The contact element is produced by ultrasonic welding one or more contact pieces onto a carrier, an intermediate layer in the form of a metal powder, for example aluminium, being interposed between the contact piece and the carrier prior to such welding in order to assist in the welding of contact pieces made of material which would otherwise be difficult to weld.

Machine for welding aluminum to aluminum

Abstract: A method of welding aluminum to aluminum by thermal resistance welding, providing good electrical and mechanical characteristics. The method uses special electrodes for thermal heat that are hard and have a high electrical resistance, such as molybdenum or tungsten alloy and also relies on the aluminum oxide coating on the aluminum to provide the desired resistance heating of the aluminum to cause welding of the aluminum material. The machine disclosed provides a means for securing aluminum leads to the start and finish end of an aluminum winding automatically and simultaneously.

Low hydrogen welding electrodes

Abstract: An improved welding electrode for producing weld metal having low amounts of hydrogen therein so that hydrogen-assisted cracking in the weld zone is minimized. This is especially beneficial for welding high strength steels having tensile strengths of about 70,000 psi and above. The electrode has a filler wire core and a flux covering of predetermined constituents and low moisture levels such as below about 0.6 percent. The flux is bound together with a binder of hydrolyzed organic silicate (silica) which makes no substantial contribution to the moisture level of the covering and which also makes the covering resistant to hygroscopic moisture pickup before the electrode is used for welding. Thus, this binder minimizes the amount of hydrogen from any moisture in the covering which may be introduced into the weld metal during welding. Additionally, the flux covering contains a source of barium or cesium in an amount effective to reduce the slag/metal reaction temperature during welding. By so reducing this temperature, the amount of hydrogen actually introduced into the weld metal from the electrode covering and binder is minimized. This reduction of the slag/metal reaction temperature during welding has been found to have the additional advantage of reducing the amount of oxygen in the weld metal. This provides increased impact properties for the weld metal.

Welding of laminations of core-plated silicon steel

Abstract: The disclosure is directed to apparatus for and a method of joining a plurality of laminations of electric steel, which are individually core-plated for electrical insulation purposes, to form a laminate structure used in the manufacture of electrical machinery. Joinder of the laminations is accomplished with the laminations in face-to-face relation and arc welding a bead transverse to the stacked lamination edges. To avoid porosity in the weld bead, the arc welding process uses microwire having a diameter of no greater than about 0.050 inches in a moving welding head that maintains the microwire in close proximity to the welding surface. The operating voltage of the arc welding apparatus is controlled to produce an operating welding current of no more than about 170 amperes. The effect of using microwire of such size under such an operating current prevents overheating and degradation of the coreplate, and results in a proper deposition of a strong, non-porous weld bead.

Arc welding apparatus and method

Abstract: An arc welding apparatus and method is described which includes a guide nozzle surrounding a non-consumable electrode and a shielding nozzle disposed outside the guide nozzle so as to feed a protecting inert gas about the electrode from a position within the guide nozzle and to feed a shielding carbon dioxide gas or a mixture of carbon dioxide gas and oxygen or other inert gas from a position within the shielding nozzle, whereby the electrode is protected by means of the guide nozzle and the protecting gas supplied therethrough and the outer portion of the arc is cooled to restrict the radial extent thereof by the shielding gas, while a deoxidizing reaction with the melted metal may be performed by means of the carbon dioxide gas and a deoxidizing agent within a welding rod when the latter is employed between the electrode and a base metal, or in the vicinity of the welding arc.

Method for controlling the shape of a molten pool in gas shield arc welding

Abstract: A method is disclosed in which gas shield arc welding is carried out while applying a gas at a higher pressure than the shield gas to the rear part of the surface of molten metal during welding. By this method, welding proceeds while the molten pool is being maintained in the desirable shape, and the welding can be performed at high currents and speeds without causing bead defects such as undercut formation or humping.

Laser beam welding using small dia beam - provides short welding times without altering props. near the weld

Abstract: In a process for the welding together of two or more materials, each possessing special physical properties, the materials are melted by a laser beam at the desired junction so that the molten zones are mixed together, but the materials outside the junction retain their original physical properties. For welding, one or more elements which are not present in the materials being welded, or only present in a minor amt., may be mixed in the molten zone. To restrict the radial spread of heat, the laser is pref. operated in the transverse TEM. mode, and the molten zone is pref. 0.1mm dia. using operational times of ca. 1 msec. Prevents the formation of zones adjacent to the weld which have different properties to those possessed by the materials being joined, e.g. transition zones. The materials being welded are pref. spring- or magneic-materials, plastics, dielectrics, ceramics, or a combination of SmCO5 with iron. The additional element(s) may improve weldability or weld-strength, or prevent cracking, and are pref. Nb, Ti or Ta when an Fe/Ni or a Cr/Fe/Ni alloy is being welded.

Apparatus for welding articles of thermoplasts

Abstract: The apparatus for welding articles of thermoplasts using additional welding material is provided with a special melting device for the welding material. The melting device comprises a guide channel for the supply and preheating of the welding material, which channel merges into a melting channel of diminishing cross section closed at one end. The melting channel is provided with lateral bores which discharge into a melting chamber of low height in communication with a collecting zone for the plasticized welding material, which collecting zone is connected with the outlet opening of the welding shoe.

Parallel Gap Welding to Thick-Film Metallization

Abstract: This study was directed at the parallel gap welding response of a series of gold and platinum-gold thick-film conductor materials which were subjected to various peak temperature/belt speed firing profiles. The parallel gap welding was conducted using a variety of weld voltage/pulse duration settings and a nominal 0.05-mm-thick by 0.38-mm-wide pure gold ribbon. Evaluation of the welds was determined through a 90° peel test. From the resulting data the following conclusions were reached. 1) Parallel gap welding is a viable approach to gold ribbon interconnection to thick film. 2) In general, thicker fired films respond better to parallel gap welding. 3) Sensitivity to firing profile, as reflected by parallel gap weld strength, is a characteristic of each specific thick-film material which must be determined and properly optimized. 4) Sensitivity to weld parameters is a characteristic of each specific material and should be optimized with firing profile. 5) The Pure gold conductor materials are not as satisfactory as platinum-gold conductors for parallel gap welding.

Flux for the submerged arc welding of ordinary, semi-alloyed or special steels

Abstract: Flux for welding ordinary, semi-alloyed, alloyed or special steels with a high rate of efficiency and high rate of speed and containing a relatively high amount of Fe powder.

Method for welding lead wires together

Abstract: A method for welding lead wires together by twisting into a strand a plurality of lead wires of electrical parts or the like, producing an arc between the strand and a carbon electrode, thereby melting and welding the strand by the heat from the arc to obtain a weld of high quality.

Fracture toughness of electroslag welded a537g steel

Abstract: This paper reports an investigation of the properties of a 2 in. thick electroslag weldment in A537G steel plate using both conventional Charpy impact tests and fracture mechanics testing methods. It was found that A537 steel normalized and stress relieved in 2 in. thickness showed good properties in notch toughness and fracture toughness tests above 100 F. In the as-welded condition, the weld metal and heat-affected zone of an electroslag weldment exhibited transition temperatures more than 100 F above the base metal and suffered corresponding losses in fracture toughness. Stress relieving erased a large fraction of the differences and normalizing plus stress relieving removed nearly all the differences in Charpy V-notch toughness of the weld metal and HAZ compared to base metal. The results of this study suggest that electroslag weldments will not provide the notch toughness expected of low temperature steels such as A537, unless heat treatment is subsequently applied.

Liquation cracking in the vveld heat-affected zone of highstrength ferritic steels

Abstract: An investigation has been made of the effect of composition and welding variables on liquation cracking in the weld heat-affected zone of low-alloy steels to specifications SAE 4130, En 24, and ASTMA 387B. It involved examination of bead-on-plate cracking tests made using the metal-inert-gas arc welding process. It was shown that cracking occurred in a discrete zone adjacent to the fusion boundary in which liquation of inclusions had taken place. The severity of cracking proved to be a function of both composition and welding variables. Under fixed welding conditions, cracking severity was related quantitatively to composition (in wt-%) by a linear regression equation of the form crack index=5·47C +27·27S+75·29P+2·79Si-2·77 In addition to confirming that increasing carbon and sulphur increased cracking, it was shown that phosphorus was a cracking promoter in its own right. For a steel of constant composition, cracking increased with (a) increased heat input/length, (b) increased depth offinger pen...