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A Remotely Controlled Welding Device for Joining Stainless Steel Tubes

Description: Abstract: The design and testing of experimental equipment for remotely joining stainless steel tubing by heliarc welding is described. This apparatus consists of a modified heliarc welding torch which is hydraulically controlled to maintain constant arc voltage. A suitable arc voltage sensing and control amplifier circuit was developed for this application.
Date: November 15, 1954
Creator: Mueller, Martin & Hecker, Eugene
Partner: UNT Libraries Government Documents Department

Role of Transport Phenomena in the Evolution of Geometry, Composition and Structure

Description: Abstract Fusion welding is used extensively in industries that support the nation's energy supply, defense, infrastructure, and standard of living. Safety and reliability of the welded joints are affected by their geometry, composition and structure. This report provides an account of the significant advances made in quantitative understanding of the geometry, composition and various aspects of the weldment structure with financial support from DOE/BES. In particular, this report provides an account of the research conducted under the grant DE-FG02-84ER45158 in this important area and lists all the publications that document the details of the technical accomplishments that resulted from the work. Investigations of heat transfer, fluid flow and alloying element vaporization during laser welding resulted in a new technique for the determination of the peak temperature in the weld pool and provided a new method to estimate weld metal composition. Studies on the interfacial phenomena in fusion welding resulted in quantitative understanding of the interrelationship between the weld metal composition and geometry and provided new knowledge as to when the surface active elements would affect the weldment geometry and when these elements would have no effect on the geometry. Partitioning of oxygen nitrogen and hydrogen between the welding environment and the weld metal was affected by the extent of the dissociation of diatomic gaseous species which depended on the nature of the plasma formed during welding. The interfacial tension of the liquid metal was also affected by the plasma and the properties of the plasma affected the concentrations of oxygen, nitrogen and hydrogen in the weld metal. Apart from the understanding of the evolution of composition and geometry of the weldments, application of transport phenomena provided useful information about various features of the weldment structure. Quantitative understanding of microstructure of the fusion zone and heat affected zone and grain structure ...
Date: November 17, 2005
Creator: DebRoy, Tarasankar
Partner: UNT Libraries Government Documents Department

Space Vessels

Description: The submarine and the spaceship fit in perfectly with the ideas of permanence and protection on which my work has been focusing. It is not coincidental that I have long been fascinated with the shapes and mechanisms of these vehicles. They are complex machines designed for a complex function; I find the precision of this to be appealing. I have used their shapes and mechanisms as design aspect in my thesis work. Also, in the studio, I have developed a type of Damascus steel bowl by modifying a technique once used for making gun barrels. I have made three small vessels inspired by spaceships and submarines using this modified technique.
Access: This item is restricted to UNT Community Members. Login required if off-campus.
Date: May 2004
Creator: Herndon, Mark
Partner: UNT Libraries

Special Welding Techniques : Final Summary Report

Description: From foreword: This is the final report on Special Welding Techniques. The work of the third and final year is discussed in detail, and the accomplishments of the first two years are summarized.
Date: January 1957
Creator: Mueller, John; Maxwell, William & Siltanen, James
Partner: UNT Libraries Government Documents Department

Electromagnetic-Acoustic-Transducer/Synthetic-Aperture System for Thick-Weld Inspection

Description: Abstract: This report describes a system based on electromagnetic-acoustic transducers (EMATs) as an approach to automated nondestructive evaluation of thick weldments (>25 mm). Good signal-to-noise ratios, often a problem with EMATs, were possibTe through careful design of the transducers and associated electronic circuits and the use of signal averaging. At 454 kHz, the transducers produce shear-horizontal waves of approximately 7-mm wavelength in steel. The long wavelength permits determination of through-thickness flaw depth from the amplitudes of scattered ultrasonic waves. A minicomputer controlled transducer positioning and acquired the digitized ultrasonic waveforms for synthetic aperture processing. The synthetic aperture technique further improved signal quality and yielded flaw localization through the weld thickness. Measurements on artificial flaws demonstrated a detectability threshold of 0.5 mm (through thickness) and sizing ability up to 2.5 mm, in agreement with theoretical predictions. Details include the design of the transducers and electronics, as well as the mechanical positioner, signal processing algorithms, and complete computer program listing.
Date: 1984
Creator: Fortunko, C. M.; Schramm, R. E.; Moulder, J. C. & McColskey, J. D.
Partner: UNT Libraries Government Documents Department

Computerization of Welding Information

Description: From abstract: The Workshop on Computerization of Welding Information, sponsored by the National Bureau of Standards and the American Welding Institute, was held August 5-6, 1986 in Knoxville, Tennessee. Forty-two welding engineers, welding managers, and computer scientists gathered to discuss the necessity and design of databases for welding information. Each subject was introduced by specialists in that area.
Date: June 1988
Creator: Siewert, T. A. & Jones, J. E.
Partner: UNT Libraries Government Documents Department

METALLURGY DIVISION QUARTERLY PROGRESS REPORT FOR PERIOD ENDING JANUARY 31, 1953

Description: A study was made of the effect of the addition of V aad Si on the properties of Th; corrosion of stainless steel in uranyl sulfate; corrosion, brazing, and welding of stainless steel; properties of Ti; method of combining deuterium and O for return to the reactor; spot welding of fuel elements; fabrication of reactor fuel elements; mechanical testing of U, Th, and stainless steel; surface rearrangements on a single crystal of Cu in contact with a saturated solution of Cu in Bi; development of cermets for reactor components; fabrication of Th-U fuel elements and Al-U alloy componerts. (J.E.D.)
Date: April 1, 1953
Creator: Bridges, W.H. ed.
Partner: UNT Libraries Government Documents Department

JOINING OF BERYLLIUM-A SURVEY OF THE UNCLASSIFIED LITERATURE

Description: The unclassified literature on the joining of beryllium was surveyed and is summarized. The fields covered are fusion welding, self-welding (diffusion- or pressure-welding), and brazing. The most successful attempts in each field are outlined and other work is referenced. (aauth)
Date: June 1, 1958
Creator: Brown, N.A.
Partner: UNT Libraries Government Documents Department

WELDING THIN-WALLED URANIUM CYLINDERS

Description: One of Its Monograph Series, The Industrial Atom.'' The development of a satisfactory process for the fusion welding of thin-walled uranium cylinders is discussed. Optimum results were obtained using the inert-gas shielded-arc method without the use of filler metal. The ductility of the welded joints, however, was lower than that of cast metal. Surface conditions and and the purity of the inert gas used affected the weld soundness. Straight polarity direct current was used for welding to achieve maximum penetration and to provide are stability. Welding must be done in the flat position. (auth)
Date: January 1, 1957
Creator: Brundige, E.L.; Taub, J.M.; Hanks, G.S. & Doll, D.T.
Partner: UNT Libraries Government Documents Department

Pulse shaping effects on weld porosity in laser beam spot welds : contrast of long- & short- pulse welds.

Description: Weld porosity is being investigated for long-pulse spot welds produced by high power continuous output lasers. Short-pulse spot welds (made with a pulsed laser system) are also being studied but to a much small extent. Given that weld area of a spot weld is commensurate with weld strength, the loss of weld area due to an undefined or unexpected pore results in undefined or unexpected loss in strength. For this reason, a better understanding of spot weld porosity is sought. Long-pulse spot welds are defined and limited by the slow shutter speed of most high output power continuous lasers. Continuous lasers typically ramp up to a simmer power before reaching the high power needed to produce the desired weld. A post-pulse ramp down time is usually present as well. The result is a pulse length tenths of a second long as oppose to the typical millisecond regime of the short-pulse pulsed laser. This study will employ a Lumonics JK802 Nd:YAG laser with Super Modulation pulse shaping capability and a Lasag SLS C16 40 W pulsed Nd:YAG laser. Pulse shaping will include square wave modulation of various peak powers for long-pulse welds and square (or top hat) and constant ramp down pulses for short-pulse welds. Characterization of weld porosity will be performed for both pulse welding methods.
Date: October 1, 2007
Creator: Ellison, Chad M. (Honeywell FM&T, Kansas City, MO); Perricone, Matthew J. (R.J. Lee Group, Inc., Monroeville, PA); Faraone, Kevin M. (BWX Technologies, Inc., Lynchburg, VA) & Norris, Jerome T.
Partner: UNT Libraries Government Documents Department

Welding Plutonium-Containing Fuel Elements

Description: Report discussing the manual and automatic welding techniques for fuel elements containing plutonium with Zircaloy-2 aluminum, and stainless steel cladding, 0.013 to 0.0889 cm (0.005 to 0.350 in.) thick" (p. 3).
Date: June 1964
Creator: Lemon, L. C.; Ross, W. T. & Bailey, W. J.
Partner: UNT Libraries Government Documents Department

Friction Stir Welding of High Strength Precipitation Strengthened Aluminum Alloys

Description: Rising demand for improved fuel economy and structural efficiency are the key factors for use of aluminum alloys for light weighting in aerospace industries. Precipitation strengthened 2XXX and 7XXX aluminum alloys are the key aluminum alloys used extensively in aerospace industry. Welding and joining is the critical step in manufacturing of integrated structures. Joining of precipitation strengthened aluminum alloys using conventional fusion welding techniques is difficult and rather undesirable in as it produces dendritic microstructure and porosities which can undermine the structural integrity of weldments. Friction stir welding, invented in 1991, is a solid state joining technique inherently benefitted to reduces the possibility of common defects associated with fusion based welding techniques. Weldability of various 2XXX and 7XXX aluminum alloys via friction stir welding was investigated. Microstructural and mechanical property evolution during welding and after post weld heat treatment was studied using experimental techniques such as transmission electron microscopy, differential scanning calorimetry, hardness testing, and tensile testing. Various factors such as peak welding temperature, cooling rate, external cooling methods (thermal management) which affects the strength of the weldment were studied. Post weld heat treatment of AL-Mg-Li alloy produced joint as strong as the parent material. Modified post weld heat treatment in case of welding of Al-Zn-Mg alloy also resulted in near 100% joint efficiency whereas the maximum weld strength achieved in case of welds of Al-Cu-Li alloys was around 80-85% of parent material strength. Low dislocation density and high nucleation barrier for the precipitates was observed to be responsible for relatively low strength recovery in Al-Cu-Li alloys as compared to Al-Mg-Li and Al-Zn-Mg alloys.
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Date: August 2016
Creator: Sidhar, Harpreet
Partner: UNT Libraries

Video Game Device Haptic Interface for Robotic Arc Welding

Description: Recent advances in technology for video games have made a broad array of haptic feedback devices available at low cost. This paper presents a bi-manual haptic system to enable an operator to weld remotely using the a commercially available haptic feedback video game device for the user interface. The system showed good performance in initial tests, demonstrating the utility of low cost input devices for remote haptic operations.
Date: May 1, 2009
Creator: Nichol, Corrie I. & Manic, Milos
Partner: UNT Libraries Government Documents Department

Weldability and microstructure development in nickel-base superalloys

Description: The integrity of nickel-base superalloy single-crystal welds depends on the weld cracking tendency, weld metal dendrite selection process, stray crystal formation, and macro- and microstructure development. These phenomena have been investigated in commercial nickel-base superalloy single crystal welds. During electron beam and laser beam welding, transverse and longitudinal weld cracking occurred. However, the weld cracking tendency was reduced with preheating. Most of the dendritic growth pattern development in these welds can be explained by a geometric model. However, the welds also contained misoriented stray crystals, which were frequently associated with weld cracks. The formation of stray crystals was related to thermal and constitutional supercooling effects. Fine-scale elemental partitioning between {gamma} and {gamma}{prime} phase was measured with atom-probe field-ion microscopy. Marked differences in partitioning characteristics in two welds were observed and are related to differences in cooling rates. In this paper, the modeling tools available to describe the above are reviewed.
Date: November 1, 1997
Creator: David, S.A.; Babu, S.S. & Vitek, J.M.
Partner: UNT Libraries Government Documents Department

Fatique Resistant, Energy Efficient Welding Program, Final Technical Report

Description: The program scope was to affect the heat input and the resultant weld bead geometry by synchronizing robotic weave cycles with desired pulsed waveform shapes to develop process parameters relationships and optimized pulsed gas metal arc welding processes for welding fatique-critical structures of steel, high strength steel, and aluminum. Quality would be addressed by developing intelligent methods of weld measurement that accurately predict weld bead geometry from process information. This program was severely underfunded, and eventually terminated. The scope was redirected to investigate tandem narrow groove welding of steel butt joints during the one year of partial funding. A torch was designed and configured to perform a design of experiments of steel butt weld joints that validated the feasability of the process. An initial cost model estimated a 60% cost savings over conventional groove welding by eliminating the joint preparation and reducing the weld volume needed.
Date: May 25, 2006
Creator: Egland, Keith & Ludewig, Howard
Partner: UNT Libraries Government Documents Department

Rapid thermal outgassing of component samples

Description: This paper/presentation describes the rapid thermal outgassing tests that were ran to provide an inventory of all gasses present in the weld channel during the weld. The component samples tested were of all materials that are exposed to the channel during the temperature excursion due to the welding operation. The temperature ramps were determined from previous weld tests. The test equipment, test procedures, and the data collection system is described. They present the data and their interpretation of it.
Date: March 26, 1999
Creator: Beat, T G & Moffitt, K
Partner: UNT Libraries Government Documents Department

Welding Development W87 Baseline

Description: This report covers the development activities used to qualify the Gas Tungsten Arc (FTA) girth weld and the resistance stem attachments on the W87 Base Line (W87BL). Design of experiments was used throughout the development activities.
Date: November 1, 1998
Creator: Newman, A.; Gibbs, G. & Hicken, G. K.
Partner: UNT Libraries Government Documents Department