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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

Manual gas tungsten arc (dc) and semiautomatic gas metal arc welding of 6XXX aluminum. Welding procedure specification

Description: Procedure WPS-1009 is qualified under Section IX of the ASME Boiler and Pressure Vessel Code for manual gas tungsten arc (DC) and semiautomatic gas metal arc (DC) welding of aluminum alloys 6061 and 6063 (P-23), in thickness range 0.187 to 2 in.; filler metal is ER4043 (F-23); shielding gases are helium (GTAW) and argon (GMAW).
Date: August 1, 1985
Creator: Wodtke, C.H.; Frizzell, D.R. & Plunkett, W.A.
Partner: UNT Libraries Government Documents Department


Description: The work performed during the three previous years can be roughly divided into two main categories: (1) development of advanced modeling techniques; and (2) modeling of arc welding process. The work in the first category comprised the development of the Order of Magnitude Scaling (OMS) technique, which is complementary to numerical modeling techniques such as finite elements, but it provides approximate formulas instead of just numerical results. Borrowing concepts from OMS, another modeling technique based on empirical data was also developed. During this stage special software was also developed. The second category comprised the application of OMS to the three main subsystems of arc welding: the weld pool, the arc, and the electrode. For each of these subsystems they found scaling laws and regimes. With this knowledge, they analyzed the generation of weld pool defects during high current arc welding, proposed a mechanistic description of the process, and possible solutions.
Date: January 1, 2003
Creator: MENDEZ,P.F. & EAGAR, T.W.
Partner: UNT Libraries Government Documents Department

Tungsten-Arc Welding of Ames Thorium and Thorium Alloys

Description: This report follows an investigation made on the welding of Ames thorium by the inert-gas-shielded tungsten-arc process as the first part of a program on the joining of thorium. This program is part of a broader research program to develop the technology of thorium.
Date: January 15, 1952
Creator: Monroe, Robert E.; Martin, D. C. & Voldrich, C. B.
Partner: UNT Libraries Government Documents Department

(Development of automated welding process for field fabrication of thick walled pressure vessels). Technical progress report for period ending June 30, 1979

Description: The following activities for this period are reported: five welding processes (GTAW, GMAW, SAW, ESW, and EBW) are reviewed, torch design modifications were completed, improved joint designs were machined, and all wires for the project were ordered. (FS)
Date: January 1, 1979
Partner: UNT Libraries Government Documents Department

Computer modeling of arc welds to predict effects of critical variables on weld penetration

Description: In recent years, there have been several attempts to study the effect of critical variables on welding by computational modeling. It is widely recognized that temperature distributions and weld pool shapes are keys to quality weldments. It would be very useful to obtain relevant information about the thermal cycle experienced by the weld metal, the size and shape of the weld pool, and the local solidification rates, temperature distributions in the heat-affected zone (HAZ), and associated phase transformations. The solution of moving boundary problems, such as weld pool fluid flow and heat transfer, that involve melting and/or solidification is inherently difficult because the location of the solid-liquid interface is not known a priori and must be obtained as a part of the solution. Because of non-linearity of the governing equations, exact analytical solutions can be obtained only for a limited number of idealized cases. Therefore, considerable interest has been directed toward the use of numerical methods to obtain time-dependant solutions for theoretical models that describe the welding process. Numerical methods can be employed to predict the transient development of the weld pool as an integral part of the overall heat transfer conditions. The structure of the model allows each phenomenon to be addressed individually, thereby gaining more insight into their competing interactions. 19 refs., 6 figs., 1 tab.
Date: January 1, 1991
Creator: Zacharia, T. & David, S.A.
Partner: UNT Libraries Government Documents Department

A dimensionless parameter model for arc welding processes

Description: A dimensionless parameter model previously developed for C0{sub 2} laser beam welding has been shown to be applicable to GTAW and PAW autogenous arc welding processes. The model facilitates estimates of weld size, power, and speed based on knowledge of the material`s thermal properties. The dimensionless parameters can also be used to estimate the melting efficiency, which eases development of weld schedules with lower heat input to the weldment. The mathematical relationship between the dimensionless parameters in the model has been shown to be dependent on the heat flow geometry in the weldment.
Date: December 31, 1994
Creator: Fuerschbach, P.W.
Partner: UNT Libraries Government Documents Department

Weld penetration and defect control

Description: Highly engineered designs increasingly require the use of improved materials and sophisticated manufacturing techniques. To obtain optimal performance from these engineered products, improved weld properties and joint reliability are a necessarily. This requirement for improved weld performance and reliability has led to the development of high-performance welding systems in which pre-programmed parameters are specified before any welding takes place. These automated systems however lack the ability to compensate for perturbations which arise during the welding process. Hence the need for systems which monitor and control the in-process status of the welding process. This report discusses work carried out on weld penetration indicators and the feasibility of using these indicators for on-line penetration control.
Date: May 15, 1992
Creator: Chin, B.A.
Partner: UNT Libraries Government Documents Department

Improvement of reliability of welding by in-process sensing and control (development of smart welding machines for girth welding of pipes). Final report

Description: Closed-loop control of the welding variables represents a promising, cost-effective approach to improving weld quality and therefore reducing the total cost of producing welded structures. The ultimate goal is to place all significant weld variables under direct closed-loop control; this contrasts with preprogrammed machines which place the welding equipment under control. As the first step, an overall strategy has been formulated and an investigation of weld pool geometry control for gas tungsten arc process has been completed. The research activities were divided into the areas of arc phenomena, weld pool phenomena, sensing techniques and control activities.
Date: April 1, 1983
Creator: Hardt, D.E.; Masubuchi, K.; Paynter, H.M. & Unkel, W.C.
Partner: UNT Libraries Government Documents Department

SmartWeld working session for the GTS4

Description: Results from SmartWeld`s first working session involving in-progress designs is presented. The Welding Advisor component of SmartWeld was thoroughly exercised, evaluated all eleven welds of the selected part. The Welding Advisor is an expert system implemented with object-oriented techniques for knowledge representation. With two welding engineers in attendance, the recommendations of the Welding Advisor were thoroughly examined and critiqued for accuracy and for areas of improvement throughout the working session. The Weld Schedule Database component of SmartWeld was also exercised. It is a historical archive of proven, successful weld schedules that can be intelligently searched using the current context of SmartWeld`s problem solving state. On all eleven welds, the experts agreed that Welding Advisor recommended the most risk free options. As a result of the Advisor`s recommendation, six welds agreed completely with the experts, two welds had their joint geometry modified for production, and three welds were not modified but extra care was exercised during welding. 25 figs., 3 tabs.
Date: August 1, 1997
Creator: Kleban, S.; Hicken, K.; Ng, R. & Fricke, B.
Partner: UNT Libraries Government Documents Department

Development of filler metals for welding of iron aluminide alloys. Final report

Description: Attempts were made to develop a coating formulation for shielded metal arc (SMA) welding electrodes for iron aluminide alloys. Core wires of various compositions were produced by aspiration casting at ORNL and coating formulation development was conducted by Devasco, Inc. It was found that, except for weld deposit compositions containing less than 10 weight % aluminum, all weld deposits exhibited extensive cold cracking and/or porosity. It was concluded that current coating formulation technology limits successful iron aluminide deposits to less than 10 weight % aluminum.
Date: June 29, 1995
Creator: Goodwin, G. M. & Scott, J. L.
Partner: UNT Libraries Government Documents Department

Closure Welding Design and Justification for Canister S00645 (Bent Flange)

Description: This report provides the design basis and justification for a closure welding technique using the manual Gas Tungsten Are Welding (GTAW) process. Other aspects affecting closure of Canister S00645, e.g., shielding, facility and administrative requirements, etc., are addressed elsewhere.
Date: December 21, 1998
Creator: Cannell, G.R.
Partner: UNT Libraries Government Documents Department

Cellular automata modeling of weld solidification structure

Description: The authors explore the use of cellular automata in modeling arc-welding processes. A brief discussion of cellular automata and their previous use in micro-scale solidification simulations is presented. Macro-scale thermal calculations for arc-welding at a thin plate are shown to give good quantitative and qualitative results. Combining the two calculations in a single cellular array provides a realistic simulation of grain growth in a welding process. Results of simulating solidification in a moving melt pool in a poly-crystalline alloy sheet are presented.
Date: December 31, 1993
Creator: Dress, W.B.; Zacharia, T. & Radhakrishnan, B.
Partner: UNT Libraries Government Documents Department

In-situ spatially resolved x-ray diffraction mapping of the alpha to beta to alpha transformation in commercially pure titanium arc welds

Description: Spatially Resolved X-Ray Diffraction (SRXRD) is used to map the {alpha}{r_arrow}{beta}{r_arrow}{alpha} phase transformation in the heat affected zone (HAZ) of commercially pure titanium gas tungsten arc welds. In-situ SRXRD experiments were conducted on arc welds using a 200 pm diameter x-ray beam at Stanford Synchrotron Radiation Laboratory (SSRL). A map was created which identifies six HAZ microstructural regions that exist between the liquid weld pool and the base metal during welding. The first region is single phase {beta}-Ti that forms in a 2- to 3-mm band adjacent to the liquid weld pool. The second region is back transformed {alpha}-Ti that forms behind the portion of the HAZ where {beta}-Ti was once present at higher temperatures. The third region is completely recrystallized {alpha}-Ti that forms in a 2- to 3-mm band surrounding the single phase {beta}-Ti region. Recrystallized {alpha}-Ti was observed by itself and also with varying amounts of {beta}-Ti. The fourth region of the weld is the partially transformed zone where {alpha}-Ti and {beta}-Ti coexist during welding. The fifth region is directly behind the partially transformed zone and consists of a mixture of recrystallized and back transformed {alpha}-Ti The sixth region is farthest from the weld pool and consists of {alpha}-Ti that is undergoing annealing and recrystallization. Annealing of the base metal was observed to some degree in all of the SRXRD patterns, showing that annealing exceeded 13 mm from the centerline of the weld. Although the microstructure consisted predominantly of {alpha}-Ti, both prior to the weld and after the weld, the (002) texture of the starting material was altered during welding to produce a predominantly (101) texture within the resulting HAZ.
Date: May 15, 1998
Creator: Elmer, J. W., LLNL
Partner: UNT Libraries Government Documents Department

Laser assisted non-consumable arc welding process development

Description: The employment of Laser Beam Welding (LBW) for many traditional arc welding applications is often limited by the inability of LBW to compensate for variations in the weld joint gap. This limitation is associated with fluctuations in the energy transfer efficiency along the weld joint. Since coupling of the laser beam to the workpiece is dependent on the maintenance of a stable absorption keyhole, perturbations to the weld pool can lead to decreased energy transfer and resultant weld defects. Because energy transfer in arc welding does not similarly depend on weld pool geometry, it is expected that combining these two processes together will lead to an enhanced fusion welding process that exhibits the advantages of both arc welding and LBW. Laser assisted non-consumable arc welds have been made on thin section aluminum. The welds combine the advantages of arc welding and laser welding, with enhanced penetration and fusion zone size. The use of a pulsed Nd:YAG laser with the combined process appears to be advantageous since this laser is effective in removing the aluminum oxide and thereby allowing operation with the tungsten electrode negative. The arc appears to increase the size of the weld and also to mitigate hot cracking tendencies that are common with the pulsed Nd:YAG laser.
Date: September 1, 1997
Creator: Fuerschach, P.W. & Hooper, F.M.
Partner: UNT Libraries Government Documents Department

Narrow groove welding gas diffuser assembly and welding torch

Description: A diffuser assembly is provided for narrow groove welding using an automatic gas tungsten arc welding torch. The diffuser assembly includes manifold adapted for adjustable mounting on the welding torch which is received in a central opening in the manifold. Laterally extending manifold sections communicate with a shield gas inlet such that shield gas supplied to the inlet passes to gas passages of the manifold sections. First and second tapered diffusers are respectively connected to the manifold sections in fluid communication with the gas passages thereof. The diffusers extend downwardly along the torch electrode on opposite sides thereof so as to release shield gas along the length of the electrode and at the distal tip of the electrode. The diffusers are of a transverse width which is on the order of the thickness of the electrode so that the diffusers can, in use, be inserted into a narrow welding groove before and after the electrode in the direction of the weld operation.
Date: February 4, 2000
Creator: Rooney, Stephen J.
Partner: UNT Libraries Government Documents Department

Proposed GTA welding specification and acceptance criteria for the MC4163

Description: This specification documents the gas tungsten arc (GTA) welding process and production weld acceptance criteria requirements for the MC4163. This document is written specifically to apply to the welds on the MC4163 and is not to be used as a general gas tungsten arc welding specification. All sections of this specification must be complied with unless specifically exempted in writing. There are a total of five welds with three different joint designs required to fabricate the MC4163. In the order of fabrication they are (1) initiator closure disc, (2) nozzle to case girth welds, two and, (3) nozzle closure disc welds, two. This specification will only address the nozzle to case girth welds and the nozzle closure disc welds.
Date: April 12, 1991
Creator: Kwiatkowski, J.J.
Partner: UNT Libraries Government Documents Department

Combining Noise Factors and Process Parameters in a Response Surface

Description: This presentation covers the strategy and analysis of an experiment to characterize a gas tungsten arc welding process. The experiment combined four uncontrolled noise factors and four controlled process parameters. A nontraditional response surface design was employed. Multiple responses were modeled. Optimal settings for the process parameters to successfully weld the widest range of the pertinent product features were identified. Thus, the process was made ''robust'' against ''noise'' factors. Comparisons are made between the experimental and analytical approach taken versus the Taguchi style of experimentation and analysis. This comparison is mainly done with respect to the information gained, such as product design criteria, incoming material specifications, and process adjustments for nonconforming material.
Date: March 19, 1998
Creator: Wyckoff, J.J.
Partner: UNT Libraries Government Documents Department

The effect of oxide inclusions on the kinetics of the austenite to ferrite transformation in low alloy steel weld metal

Description: Isothermal transformation kinetics of austenite to acicular ferrite and allotriomorphic ferrite were measured in reheated low alloy steel weld deposits with similar weld compositions and austenite grain size but different inclusion characteristics. Accelerated kinetics of transformation to acicular ferrite were observed in weld metal containing coarser and titanium-rich inclusions. In contrast, kinetics of transformation to allotriomorphic ferrite were not influenced by inclusion characteristics, but, rather, by the austenite grain size and carbon concentration.
Date: September 1, 1994
Creator: Babu, S. S.; David, S. A.; Vitek, J. M. & DebRoy, T.
Partner: UNT Libraries Government Documents Department

Finite element analysis of arc welding

Description: Analytical models of the gas tungsten-arc welding process into finite element computer programs provides a valuable tool for determining the welding thermal cycle, weld bead shape, and penetration characteristics, as well as for evaluating the stresses and distortions generated as a result of the temperature transients. The analysis procedures are applicable to planar or axisymmetric welds with arbitrary cross-sectional geometries, under quasistationary conditions. The method used for determining temperatures features an iteration procedure to accurately account for the latent heat absorbed during melting and liberated during solidification of the weld. By simulating the heat input from the arc to the workpiece by a normal distribution function, temperature transients, weld bead dimensions, and cooling rates are evaluated as functions of both the magnitude and distribution of heat input, weldment geometry, and weld speed (or duration of heating for stationary arcs). Modeling of the welding thermal cycle is a prerequisite to analytical treatments of metallurgical changes in weld metal and heat-affected zone material, residual stresses and distortions, and weld defects. A quasistationary formulation for moving welds enables temperatures to be calculated using a two-dimensional heat conduction computer program. The present limitation of high welding speed can, however, be relaxed without altering the two-dimensional framework of the procedure.
Date: January 1, 1980
Creator: Friedman, E.
Partner: UNT Libraries Government Documents Department

Surface preparation effects on GTA (gas tungsten arc) weld penetration in JBK-75 stainless steel

Description: The results of a study are reported here on the effects of surface preparation on the shape of GTA welds on JBK-75, an austenitic precipitation hardenable stainless steel similar to A286. Minor changes in surface (weld groove) preparation produced substantial changes in the penetration characteristics and welding behavior of this alloy. Increased and more consistent weld penetration (higher d/w ratios) along with improved arc stability and less arc wander result from wire brushing and other abrasive surface preparations, although chemical and machining methods did not produce any improvement in penetration. Abrasive treatments roughen the surface, increase the surface area, and increase the surface oxide thickness. The increased weld d/w ratio is attributed to oxygen added to the weld pool from the surface oxide on the base metal. The added oxygen alters the surface-tension driven fluid flow pattern in the weld pool. Similar results were observed with changes in filler wire surface oxide thickness, caused by changes in wire production conditions. 15 refs., 14 figs., 4 tabs.
Date: January 1, 1989
Creator: Campbell, R.D.; Heiple, C.R.; Sturgill, P.L.; Robertson, A.M. & Jamsay, R.
Partner: UNT Libraries Government Documents Department

Automated welding of nuclear piping systems

Description: Automated welding, or more broadly, automatic and mechanized welding processes, has found a role in nuclear power plant fabrication. This role has expanded from a rare or isolated application to relatively frequent usage in the last five years. More importantly, it is envisioned that use of automated welding will be increasing at an accelerated rate as broader exposure to this technology is achieved. Among the various pipe welding processes, the only one which has been developed for mechanized and automated nuclear piping welding is the gas tungsten arc welding (GTAW) process. This development has occurred in the past 10 to 15 years through the steady improvement and commmercialization of orbiting welding heads. Improvements in GTAW power supplies, control systems, etc., have aided this commercialization but the main element and pacing item has been the welding head itself. In order to review the status of mechanized and automated nuclear pipe welding, the topics of basic process equipment, joint design, fit-up requirements, welding parameters, and producibility will be addressed. In addition, anticipated future developments in automated systems will be discussed.
Date: January 1, 1979
Creator: Hood, D W
Partner: UNT Libraries Government Documents Department