Showing papers on "Heat-affected zone published in 1973"

Deep narrow gap welding torch

Abstract: A welding torch adapted for welding deep narrow gaps wherein shielding gas diffusers fit inside the welding groove, a plastic liner is placed deep inside the torch so electric contact between the filler wire and contact tube is close to the exit, and a zirconia oxide insulation prevents torch contact with the gap walls.

Deep penetration welding using lasers

Abstract: A TEMoo mode laser beam is focused on a material to be welded to a power density sufficiently high, depending upon the material of the workpiece, so that deep penetration welding occurs producing a weld having a depth-to-width ratio substantially greater than 1. To initiate the weld, the incident power density and power must be sufficiently high to overcome the relatively high reflectivity of metallic workpieces. With relative movement between the workpiece and the beam, seam welding can be performed, as well as lap welding and blind welding.

Welding torch for underwater welding

Abstract: The invention relates to a welding torch for welding underwater and to a method of underwater welding using the welding torch. A high speed stream of water is directed from a nozzle on the welding torch obliquely onto a member or members to be welded to form a flared-out curtain of water. Gas is injected into the volume enclosed by the curtain of water to create a gaseous atmosphere and welding is carried out in the gaseous atmosphere.

Method for welding iron steel and nonferrous alloy

Abstract: In welding iron, steel, and nonferrous alloys, the wire feed is changed periodically and in synchronism with periodic changes of the electric welding current to establish a previously defined relation between the welding current value and the arc length. The welding current is varied between one producing a spray transfer arc and a current just maintaining the arc.

Fluxes and slags in welding

Abstract: The complex welding technology of today demands an understanding of the formulation, manufacture, performance and use of welding fluxes. The volume of fluxes used in covered-electrode, submerged-arc, flux-cored wire, electroslag, brazing and oxyacetylene techniques, has grown to a total of probably over 400 million pounds per year in the United States. The fact that in the U.S. today the covering on coated electrodes averages approximately 25% of the 600 to 700-million pound annual production is an indication of the importance of welding fluxes. The technology leading to proper flux formulation has been little understood. It is hoped that a presentation of some of the principles of welding flux technology will provide an appreciation of improved quality of weld metal obtained through slag/metal reactions. The choice of compounds and the exact formulation in the preparation of a flux will depend upon many factors, including both technical and production economies.

Grain refinement control in tig arc welding

Abstract: A method for controlling grain size and weld puddle agitation in a tungsten electrode inert gas welding system to produce fine, even grain size and distribution is disclosed In the method the frequency of DC welding voltage pulses supplied to the welding electrode is varied over a preselected frequency range and the arc gas voltage is monitored At some frequency in the preselected range the arc gas voltage will pass through a maximum By maintaining the operating frequency of the system at this value, maximum weld puddle agitation and fine grain structure are produced

Vertical welding of heavy aluminum alloy plates

Abstract: A system for welding large aluminum alloy plates in a single vertical pass by the gas metal-arc (GMA) process wherein the technique comprises spacing square butt edges of the plates about three-fourths inch to form the welding gap; oscillating between defined dwell limits a welding electrode across the gap at comparatively high rate to deposit thin layers of weld metal, and confining the weld metal by dams having facing surfaces of molded high-density electrographitic material machined to high finish respectively. The dams together with the welding head are moved vertically upward at a smooth, uniform rate to preclude any objectionable jerking movement of the facing surfaces.

Forge welding with induction coil heating

Abstract: Two adjacent re-entrant surfaces of metal parts to be welded together, at least one of the parts having metal extending in a direction away from an edge of its surface, and the metal immediately adjacent to such surfaces are heated to forge welding temperature by an induction coil supplied with an electric current having a magnitude and frequency for a time which will cause such heating without significant melting of the metal or over-heating and consequent damage to the remainder of the parts and after the forge welding temperature is reached, pressure sufficient to forge weld the parts together at such surfaces is applied to the parts.

Method of plasma-MIG-welding

Abstract: A method of plasma-MIG-welding in which welding is carried out with the electrode and the welding wire connected to the positive terminal; by varying the current in the welding wire, a variation of the character of the MIG-arc and of the way of material transfer are obtained; at low current in the welding wire, a MIG-arc with a contracted cylindrical shape and a concentrated material transfer is obtained; at high current a rotating MIG-arc and a controlled, spread material transfer are obtained.

Submerged arc welding process for very low-temperature steel and welded product

Abstract: A submerged arc welding process forming a welded steel joint consisting of said steel pieces joined by weld metal having superior impact resistance at low temperatures, said weld metal consisting essentially of up to 0.1% carbon, less than 0.4% silicon, between 1.2% and 1.7% manganese, between 0.08% and 0.5% molybdenum, between 0.02% and 0.05% titanium, between 0.0012% and 0.004% boron, up to 4% nickel, and less than 0.045% oxygen. The process utilizes specified low-temperature steel base metal which is to be welded; specified welding electrodes; and a flux.

Welding electrode structure and filler wire mechanism for an automatic welding apparatus

Abstract: In an automatic welding apparatus wherein the welding electrode is to move longitudinally in a prescribed path to produce a weld bead upon a workpiece, the welding electrode and welding electrode housing being pivotally mounted in respect to the welding apparatus housing, a shaft interconnecting the welding electrode housing and the welding apparatus housing, the shaft being movable in predetermined increments to effect precise angular movement of the welding electrode housing with respect to the welding apparatus housing, a filler wire mechanism being universally mounted in respect to the welding apparatus housing, a portion of the filler wire mechanism being pivotal along with the welding electrode housing.

Welding method and materials

Abstract: Methods and materials for submerged arc welding for obtaining a high toughness welded metal containing titanium and boron by using a flux cored wire composed of a steel sheath and a core containing titanium and boron with the addition of a metal fluoride.

Welding of copper and iron

Abstract: A method for welding copper or a copper base alloy and iron or an iron base alloy characterized in that an element for enhancing the mutual miscibility of copper and iron and an element for refining the crystal grains of the weld metal is added to weld metal in a total amount of 1 to 25 percent by weight based on the weld metal, thereby preventing the welded portion from crack formation and segregation.

Welding apparatus with consumable welding wire

Abstract: In welding apparatus employing a consumable welding wire, the wire feed rate and the welding source voltage, as parameters of the required welding energy and for the proper functioning of the welding process, should be precisely adapted to each other if a weld of high quality is to be attained under varying welding conditions. The invention provides a solution for this by measuring the wire feed rate as a parameter and by controlling control devices in the welding circuit by means of this parameter. This considerably simplifies adjustment of the welding equipment, thus enabling remote control, for example, from the welding torch, also during welding. An advantage is that the operator can introduce small, continuous variations of the welding voltage during welding.

Process for welding explosive-clad metal sheets

Abstract: A process for welding explosive-clad metal sheets together with one another and/or with metal pipes, connecting elements, or the like, includes producing at least one unjoined zone between the base metal and the cladding metal in a defined manner during an explosive cladding step, and thereafter welding in the region of at least one of unjoined zones.

Method and means for controlling adjacent arcs

Abstract: This invention relates to arc welding apparatus and describes a method and means for producing welds in which the metal in the weld area is of higher ductility than has been produced in welds made with conventional welding apparatus. Two welding torches are utilized one closely following the other. A magnetic field is directed across the arc formed by each torch so as to produce a force which is directed opposite to the force created by currents flowing in the same direction through the adjacent arcs. This latter force would otherwise cause the arcs to move towards each other and be erratic and inconsistent in their effect.

High frequency vibratory spot welding of sheet metal

Abstract: This disclosure relates to spot welding of sheet metal members by the use of high frequency vibratory energy. One of the members to be welded is provided with weld locations which are vibration isolated to inhibit propagation of vibratory energy between adjacent weld locations during the weld cycle and thereby prevent the rupture of an adjacent and previously made weld.

Considerations about the reliability of nuclear pressure vessels status and research planning

Abstract: Second lnternational Conference on Pressure Vessel Technology. l. New York; American Society of Mechanical Engineers (1973). From 2nd international congress for pressure vessel and piping technology; San Antonio, Texas, USA (1 Oct 1973). See CONF731003-P1. The Research Program Reactor Safety of the government of the Federal Republic of Germany (FRG) consists of two subprograms: Accidents and Engineered Safeguards'' and Improvement of Operational Safety''. A Status Report Reactor Pressure Vessels (RPV) shall analyze the situation in the field of pressure vessels of light water reactors (LWR) and thus provide a basis for research planning. At the end of 1972 a research project Priority Program 22 NiMoCr 37'' has been initiated. Prior to other activities, it is expected to yield information on special welding problems. Nonoptimal fabrication conditions may cause incipient cracks and/or decreased toughness in plates and forgings. Incipient cracks in the heat affected zone (HAZ) of connecting welds, as have been observed, represent a particular problem. The open boundary conditions in the practical application of fracture mechanics technology consist of the exact determination of critical states in the material and, also, in the evaluation of special types of cracking and of residual stresses. (auth)

Weld rod containing manganese

Abstract: A cored wire welding electrode for welding cast iron having an outer sheath made of nickel or a nickel-iron alloy and a powedered core composition containing copresent metallic magnesium and graphite and slag-forming ingredients along with special amounts of manganese. The electrode is particularly useful for open arc welding wherein a high strength weld deposit is required.

Structure and phase composition of weldments in the Zr−2.5Nb alloy

Abstract: 1. The structure and phase composition of the heat-affected zone and the weld seam of electron-beam weldments in a zirconium alloy with 2.5% Nb are different from those in the base metal and result from quenching of the alloy from the β and α+β regions that occurs in the process of welding. 2. Annealing causes equalization of the phase composition in all areas of the weld. The annealing time required is ≥28 h at 550°, ≥10 h at 590°, and ≥1 h at 700°.

Process of welding a high tension steel

Abstract: A process of welding a high tension steel comprising welding said high tension steel by the Metal-arc-Inert-Gas welding method with an electrode by which a metastable austenitic steel weld metal is obtained and, thereafter, subjecting said welded high tension steel to (1) a sub-zero cooling to transform the austenitic steel into martensitic steel and (2) an aging treatment at a temperature and for a period of time sufficient to improve the tensile strength and yield strength of the product.

Weld Optimisation and Fatigue Tests on Low Voltage Electron Beam Welded 2in (51mm) Thick Ti-6A1-4V Alloy

Abstract: Welding trials have been carried out on 2 in thick Ti-6A1-4V bar using a 60kV 15kW Sciaky electron beam welding machine. Optimum single pass, butt welding conditions were determined using visual, radiographic, ultrasonic and metallographic inspection, across weld hardness surveys and tensile tests. Narrow, full penetration welds with almost parallel cross sections were produced. A stress relieving treatment for the joints was determined from the results of stress relaxation tests on weld metal and on parent metal.

Plasma Arc Welding for Thick Plate (Report 1)

Abstract: This study was conducted as a preliminary research for further development of some plasma arc welding methods for thick plate above 10 mm.The large plasma torch and the control equipment designed to be proof against up to 1000 A with straight polarity connection have been fabricated especially for this study in our laboratory. With the ues of these equipments a series of experiments was carried out on the arc characteristics, welding conditions and welding sound.Conclusions obtained are summarized as follows:1) Thermal efficiency of plasma arc is in range of 53-60% and its heat losses to cathode, nozzle, shield cover and the other parts are 2, 20, 9-11 and 7-11% respectively at 500 A arc current.2) The Va-I (arc voltage vs. arc current), Va-Qp (arc voltage vs. plasma gas flow rate), and Va-la (arc voltage vs. arc length) characteristics of plasma arc at 300-500 A have been obtained as linear relationships whose slopes are in range of 0.02-0.05 V/A, 0.4-0.6 V/l/min and 0.4-0.6 V/mm respectively.3) The optimum welding conditions for plasma arc welding of 6, 8 and 10 mm thick mild steel plates have been evaluated in connection with welding speed, welding current, and arc constricting wall length of nozzle.4) In plasma arc welding of 16 mm thick mild steel plates, weld beads were produced as burn through or incomplete penetration beads. When the plates were backed up with copper plates, unstable plasma arc and sometimes series arcing occured and resulted in a defective bead.5) The frequency characteristic evaluation of plasma arc welding sound reveals that welding sound consists of mainly 300 Hz frequency as fundamental tone and its higher harmonics due to current pulsating (300 Hz frequency) in full wave rectification, and also that frequency characteristic is subject to the influence of welding condition mainly in above 2kHz frequency range.

Method of submerged arc welding of high tension steel workpieces

Abstract: Submerged arc welding of high tension steel workpieces by using bonded flux capable of generating at least 7 percent by weight of carbon dioxide gas during welding operation and producing slag with a basicity B L of not smaller than 1.0, in conjunction with a welding wire capable of providing alloying elements to weld metal, so as to produce weld metal having a high toughness and a high crack-resistivity.

AN IMPROVED DIFFUSION WELDING TECHNIQUE FOR TD-NiCr SHEET

Abstract: An improved diffusion-welding technique was developed to join TD-N-Cr sheet. Compared with results of previous work, this improved technique has the advantages of shonter welding time, lower welding temperature, lower welding pressure (in the most preferred form), and a simpler and more reproducible surfacepreparation procedure. Weldments were made that had base metal creep- rupture shear strength at 1100 deg C of 20 MN/m/sup 2/. Specially processed (unrecrystallized) and commercial TD-NiCr were effectively welded using the improved welding technique. However, the specially processed material was preferred over the commercial material since the weld line could be eliminated, creep-rupture fracture of weldments took place in the base metal away from weld line, and the creep-rupture shear strength of weldments was higher than that of welds made in commercial TD-NiCr. With the commercial TD-NiCr, a semi-continuous weld line resulted and creep-rupture shear fracture took place at this weld line indicating a plane of weakness. Specially processed material was also welded to commercial material with the improved technique. These welds looked very promising and performed similarly to the welds in specially processed material. Previous work resulted in the recommendation that a 600 grit sanded plus electropolished surface preparation be used prior to diffusion weldingmore » either specially processed or commercial TD-NiCr. (auth)« less