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Sample records for advance revolutionary weld

  1. Innovative Tools Advance Revolutionary Weld Technique

    Science.gov (United States)

    2009-01-01

    The iconic, orange external tank of the space shuttle launch system not only contains the fuel used by the shuttle s main engines during liftoff but also comprises the shuttle s backbone, supporting the space shuttle orbiter and solid rocket boosters. Given the tank s structural importance and the extreme forces (7.8 million pounds of thrust load) and temperatures it encounters during launch, the welds used to construct the tank must be highly reliable. Variable polarity plasma arc welding, developed for manufacturing the external tank and later employed for building the International Space Station, was until 1994 the best process for joining the aluminum alloys used during construction. That year, Marshall Space Flight Center engineers began experimenting with a relatively new welding technique called friction stir welding (FSW), developed in 1991 by The Welding Institute, of Cambridge, England. FSW differs from traditional fusion welding in that it is a solid-state welding technique, using frictional heat and motion to join structural components without actually melting any of the material. The weld is created by a shouldered pin tool that is plunged into the seam of the materials to be joined. The tool traverses the line while rotating at high speeds, generating friction that heats and softens but does not melt the metal. (The heat produced approaches about 80 percent of the metal s melting temperature.) The pin tool s rotation crushes and stirs the plasticized metal, extruding it along the seam as the tool moves forward. The material cools and consolidates, resulting in a weld with superior mechanical properties as compared to those weld properties of fusion welds. The innovative FSW technology promises a number of attractive benefits. Because the welded materials are not melted, many of the undesirables associated with fusion welding porosity, cracking, shrinkage, and distortion of the weld are minimized or avoided. The process is more energy efficient, safe

  2. Advanced Welding Concepts

    Science.gov (United States)

    Ding, Robert J.

    2010-01-01

    Four advanced welding techniques and their use in NASA are briefly reviewed in this poster presentation. The welding techniques reviewed are: Solid State Welding, Friction Stir Welding (FSW), Thermal Stir Welding (TSW) and Ultrasonic Stir Welding.

  3. Advanced Welding Applications

    Science.gov (United States)

    Ding, Robert J.

    2010-01-01

    Some of the applications of advanced welding techniques are shown in this poster presentation. Included are brief explanations of the use on the Ares I and Ares V launch vehicle and on the Space Shuttle Launch vehicle. Also included are microstructural views from four advanced welding techniques: Variable Polarity Plasma Arc (VPPA) weld (fusion), self-reacting friction stir welding (SR-FSW), conventional FSW, and Tube Socket Weld (TSW) on aluminum.

  4. Diversionary device history and revolutionary advancements.

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Paul W.; Grubelich, Mark Charles

    2005-04-01

    Diversionary devices also known as flash bangs or stun grenades were first employed about three decades ago. These devices produce a loud bang accompanied by a brilliant flash of light and are employed to temporarily distract or disorient an adversary by overwhelming their visual and auditory senses in order to gain a tactical advantage. Early devices that where employed had numerous shortcomings. Over time, many of these deficiencies were identified and corrected. This evolutionary process led to today's modern diversionary devices. These present-day conventional diversionary devices have undergone evolutionary changes but operate in the same manner as their predecessors. In order to produce the loud bang and brilliant flash of light, a flash powder mixture, usually a combination of potassium perchlorate and aluminum powder is ignited to produce an explosion. In essence these diversionary devices are small pyrotechnic bombs that produce a high point-source pressure in order to achieve the desired far-field effect. This high point-source pressure can make these devices a hazard to the operator, adversaries and hostages even though they are intended for 'less than lethal' roles. A revolutionary diversionary device has been developed that eliminates this high point-source pressure problem and eliminates the need for the hazardous pyrotechnic flash powder composition. This new diversionary device employs a fuel charge that is expelled and ignited in the atmosphere. This process is similar to a fuel air or thermobaric explosion, except that it is a deflagration, not a detonation, thereby reducing the overpressure hazard. This technology reduces the hazard associated with diversionary devices to all involved with their manufacture, transport and use. An overview of the history of diversionary device development and developments at Sandia National Laboratories will be presented.

  5. Advances in welding science and technology

    International Nuclear Information System (INIS)

    Over the years, welding has been more of an art than a science, but in the last few decades major advances have taken place in welding science and technology. With the development of new methodologies at the crossroads of basic and applied sciences, enormous opportunities and potential exist to develop a science-based design of composition, structure, and properties of welds with intelligent control and automation of the welding processes. In the last several decades, welding has evolved as an interdisciplinary activity requiring synthesis of knowledge from various disciplines and incorporating the most advanced tools of various basic applied sciences. A series of international conferences and other publications have covered the issues, current trends and directions in welding science and technology. In the last few decades, major progress has been made in (i) understanding physical processes in welding, (ii) characterization of microstructure and properties, and (iii) intelligent control and automation of welding. This paper describes some of these developments

  6. Advances in welding science - a perspective

    International Nuclear Information System (INIS)

    The ultimate goal of welding technology is to improve the joint integrity and increase productivity. Over the years, welding has been more of an art than a science, but in the last few decades major advances have taken place in welding science and technology. With the development of new methodologies at the crossroads of basic and applied sciences, enormous opportunities and potential exist to develop a science-based tailoring of composition, structure, and properties of welds with intelligent control and automation of the welding processes

  7. Pulsed Magnetic Welding for Advanced Core and Cladding Steel

    Energy Technology Data Exchange (ETDEWEB)

    Cao, Guoping [Univ. of Wisconsin, Madison, WI (United States); Yang, Yong [Univ. of Florida, Gainesville, FL (United States)

    2013-12-19

    To investigate a solid-state joining method, pulsed magnetic welding (PMW), for welding the advanced core and cladding steels to be used in Generation IV systems, with a specific application for fuel pin end-plug welding. As another alternative solid state welding technique, pulsed magnetic welding (PMW) has not been extensively explored on the advanced steels. The resultant weld can be free from microstructure defects (pores, non-metallic inclusions, segregation of alloying elements). More specifically, the following objectives are to be achieved: 1. To design a suitable welding apparatus fixture, and optimize welding parameters for repeatable and acceptable joining of the fuel pin end-plug. The welding will be evaluated using tensile tests for lap joint weldments and helium leak tests for the fuel pin end-plug; 2 Investigate the microstructural and mechanical properties changes in PMW weldments of proposed advanced core and cladding alloys; 3. Simulate the irradiation effects on the PWM weldments using ion irradiation.

  8. Revolutionary Science.

    Science.gov (United States)

    Casadevall, Arturo; Fang, Ferric C

    2016-01-01

    On rare occasions in the history of science, remarkable discoveries transform human society and forever alter mankind's view of the world. Examples of such discoveries include the heliocentric theory, Newtonian physics, the germ theory of disease, quantum theory, plate tectonics and the discovery that DNA carries genetic information. The science philosopher Thomas Kuhn famously described science as long periods of normality punctuated by times of crisis, when anomalous observations culminate in revolutionary changes that replace one paradigm with another. This essay examines several transformative discoveries in the light of Kuhn's formulation. We find that each scientific revolution is unique, with disparate origins that may include puzzle solving, serendipity, inspiration, or a convergence of disparate observations. The causes of revolutionary science are varied and lack an obvious common structure. Moreover, it can be difficult to draw a clear distinction between so-called normal and revolutionary science. Revolutionary discoveries often emerge from basic science and are critically dependent on nonrevolutionary research. Revolutionary discoveries may be conceptual or technological in nature, lead to the creation of new fields, and have a lasting impact on many fields in addition to the field from which they emerge. In contrast to political revolutions, scientific revolutions do not necessarily require the destruction of the previous order. For humanity to continue to benefit from revolutionary discoveries, a broad palette of scientific inquiry with a particular emphasis on basic science should be supported. PMID:26933052

  9. Revolutionary Science

    Science.gov (United States)

    Fang, Ferric C.

    2016-01-01

    ABSTRACT On rare occasions in the history of science, remarkable discoveries transform human society and forever alter mankind’s view of the world. Examples of such discoveries include the heliocentric theory, Newtonian physics, the germ theory of disease, quantum theory, plate tectonics and the discovery that DNA carries genetic information. The science philosopher Thomas Kuhn famously described science as long periods of normality punctuated by times of crisis, when anomalous observations culminate in revolutionary changes that replace one paradigm with another. This essay examines several transformative discoveries in the light of Kuhn’s formulation. We find that each scientific revolution is unique, with disparate origins that may include puzzle solving, serendipity, inspiration, or a convergence of disparate observations. The causes of revolutionary science are varied and lack an obvious common structure. Moreover, it can be difficult to draw a clear distinction between so-called normal and revolutionary science. Revolutionary discoveries often emerge from basic science and are critically dependent on nonrevolutionary research. Revolutionary discoveries may be conceptual or technological in nature, lead to the creation of new fields, and have a lasting impact on many fields in addition to the field from which they emerge. In contrast to political revolutions, scientific revolutions do not necessarily require the destruction of the previous order. For humanity to continue to benefit from revolutionary discoveries, a broad palette of scientific inquiry with a particular emphasis on basic science should be supported. PMID:26933052

  10. Welding advances in power plant construction. Orbital TIG welding

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, T. (Babcock and Wilcox Ltd., Renfrew (UK))

    1984-09-01

    The second in a series of articles outlining areas in which modern welding technology has been applied to the production of components for the power industry. The experience gained in the manufacture of AGR boilers led to work on the development of mechanised orbital TIG welding. Some of this development work, carried out for both fossil fired and nuclear powered stations, is detailed.

  11. Laser welding of advanced high strength steels

    OpenAIRE

    Ahmed, Essam Ahmed Ali

    2011-01-01

    This research work focuses on characterization of CO2 laser beam welding (LBW) of dual phase (DP) and transformation induced plasticity (TRIP) steel sheets based on experimental, numerical simulation and statistical modeling approaches. The experimental work aimed to investigate the welding induced-microstructures, hardness, tensile properties and formability limit of laser welding butt joints of DP/DP, TRIP/TRIP and DP/TRIP steel sheets under different welding speeds. The effects of shieldin...

  12. Resistance Welding of Advanced Materials and Micro Components

    DEFF Research Database (Denmark)

    Friis, Kasper Storgaard

    , thermal, electrical and metallurgical effects all signifcantly in uencing the process. Modelling is further complicated when down-scaling the process for welding micro components or when welding new advanced high strength steels in the automotive industry. The current project deals with three main themes...... resistance is addressed both theoretically and experimentally. Secondly the consequences of downscaling the process is investigated experimentally and discussed in relation to simulation of the process. Finally resistance welding of advanced high strength steels is addressed aimed at improving the simulation...... of the final weld properties. The temperature dependent material rheology of dierent advanced high strength steels and other materials, often resistance welded, were measured using hot tensile testing and hot compression testing. It is found that the Hollomon equation is capable of modelling material...

  13. Fundamentals and advances in the development of remote welding fabrication systems

    Science.gov (United States)

    Agapakis, J. E.; Masubuchi, K.; Von Alt, C.

    1986-01-01

    Operational and man-machine issues for welding underwater, in outer space, and at other remote sites are investigated, and recent process developments are described. Probable remote welding missions are classified, and the essential characteristics of fundamental remote welding tasks are analyzed. Various possible operational modes for remote welding fabrication are identified, and appropriate roles for humans and machines are suggested. Human operator performance in remote welding fabrication tasks is discussed, and recent advances in the development of remote welding systems are described, including packaged welding systems, stud welding systems, remotely operated welding systems, and vision-aided remote robotic welding and autonomous welding systems.

  14. Advanced Gas Tungsten Arc Weld Surfacing Current Status and Application

    Directory of Open Access Journals (Sweden)

    Stephan Egerland

    2015-09-01

    Full Text Available Abstract Gas Shielded Tungsten Arc Welding (GTAW – a process well-known providing highest quality weld results joined though by lower performance. Gas Metal Arc Welding (GMAW is frequently chosen to increase productivity along with broadly accepted quality. Those industry segments, especially required to produce high quality corrosion resistant weld surfacing e.g. applying nickel base filler materials, are regularly in consistent demand to comply with "zero defect" criteria. In this conjunction weld performance limitations are overcome employing advanced 'hot-wire' GTAW systems. This paper, from a Welding Automation perspective, describes the technology of such devices and deals with the current status is this field – namely the application of dual-cathode hot-wire electrode GTAW cladding; considerably broadening achievable limits.

  15. Revolutionary Securitization

    DEFF Research Database (Denmark)

    Holbraad, Martin; Pedersen, Morten Axel

    2012-01-01

    This article proposes an anthropological extension of the so-called Copenhagen School theory of securitization in International Relations. In contrast to existing attempts to show how, suitably elaborated, this model can be ‘applied’ to various non-Western contexts, our anthropological strategy is...... its premises. In its paradigmatic form, we argue, the model is liberal in that its abiding concern with states of emergency turns on an ontological distinction between political subjects (e.g. people) and political structures (e.g. state). By contrast, revolutionary politics in Cuba concertedly...... rescinds just this distinction, to bring about an alternative, non-liberal political ontology. We then go on to use the Cuban case to construct an alternative model of securitization, which we call revolutionary. On this model, the move of securitization pertains, not to a passage from ordinary politics...

  16. Overview of advanced process control in welding within ERDA

    International Nuclear Information System (INIS)

    The special kinds of demands placed on ERDA weapons and reactors require them to have very reliable welds. Process control is critical in achieving this reliability. ERDA has a number of advanced process control projects underway with much of the emphasis being on electron beam welding. These include projects on voltage measurement, beam-current control, beam focusing, beam spot tracking, spike suppression, and computer control. A general discussion of process control in welding is followed by specific examples of some of the advanced joining process control projects in ERDA

  17. Welding advances in power plant construction

    International Nuclear Information System (INIS)

    The second in a series of articles outlining areas in which modern welding technology has been applied to the production of components for the power industry. The experience gained in the manufacture of AGR boilers led to work on the development of mechanised orbital TIG welding. Some of this development work, carried out for both fossil fired and nuclear powered stations, is detailed. (U.K.)

  18. Weldability and weld properties for advanced power plant materials

    Energy Technology Data Exchange (ETDEWEB)

    Cerjak, H.; Letofsky, E. [Graz Univ. of Technology, Graz (Austria); Jochum, C. [Thyssen Schweisstechnik, Hamm (Germany); Nies, H. [Oerlikon Schweisstechnik, Eisenberg (Germany)

    2002-07-01

    This paper shows the contributions of the suppliers of consumables, foundries and research institutes to the European COST program 522 for the development of new Co modified 9-12% Cr-steels. The characterisation of welded joints in advanced high creep resistant steels is of decisive importance in the design of modern power stations. The key to solve these takes in the understanding of the metallurgical behaviour of the different microstructures appearing in the welded joint - base material, heat affected zone and weld deposit under creep exposure conditions. (orig.)

  19. Friction Stir Spot Welding of Advanced High Strength Steels

    Energy Technology Data Exchange (ETDEWEB)

    Hovanski, Yuri; Santella, M. L.; Grant, Glenn J.

    2009-12-28

    Friction stir spot welding was used to join two advanced high-strength steels using polycrystalline cubic boron nitride tooling. Numerous tool designs were employed to study the influence of tool geometry on weld joints produced in both DP780 and a hot-stamp boron steel. Tool designs included conventional, concave shouldered pin tools with several pin configurations; a number of shoulderless designs; and a convex, scrolled shoulder tool. Weld quality was assessed based on lap shear strength, microstructure, microhardness, and bonded area. Mechanical properties were functionally related to bonded area and joint microstructure, demonstrating the necessity to characterize processing windows based on tool geometry.

  20. Einstein's revolutionary paper

    International Nuclear Information System (INIS)

    Although Einstein wrote five fundamental papers in 1905, only one - the article showing that light consists of discrete quantum particles - was truly revolutionary, argues John S. Rigden. Einstein's annus mirabilis of 1905 is rightly a cause for celebration. In less than seven months, Einstein wrote five history-making papers. He proposed the particle theory of light, developed a method to measure molecular dimensions, explained the long-puzzling Brownian motion, developed the theory of special relativity, and he finished his intellectual sprint by producing the world's most famous equation, E = mc2. The creative outpouring that Einstein exhibited in 1905 stands alone in the history of physics. After 100 years of sweeping advances in the subject since then, the content of these papers remains at the bedrock of our discipline. But although all of Einstein's 1905 papers were fundamental, only one paper was truly revolutionary. What makes a physics paper revolutionary? Perhaps the most important requirement is that it contains a 'big idea'. Next, the big idea must contradict the accepted wisdom of its time. Third, physicists capable of judging the intrinsic merit of the big idea typically reject it until they are forced to accept it. Finally, the big idea must survive and eventually become part of the woodwork of physics. Only Einstein's March paper 'On a heuristic point of view concerning the production and transformation of light' (Ann. Phys., Lpz 17 132-148) meets these criteria. (U.K.)

  1. Advanced computer architecture specification for automated weld systems

    Science.gov (United States)

    Katsinis, Constantine

    1994-01-01

    This report describes the requirements for an advanced automated weld system and the associated computer architecture, and defines the overall system specification from a broad perspective. According to the requirements of welding procedures as they relate to an integrated multiaxis motion control and sensor architecture, the computer system requirements are developed based on a proven multiple-processor architecture with an expandable, distributed-memory, single global bus architecture, containing individual processors which are assigned to specific tasks that support sensor or control processes. The specified architecture is sufficiently flexible to integrate previously developed equipment, be upgradable and allow on-site modifications.

  2. Advanced Functions of a Modern Power Source for GMAW Welding of Steel

    OpenAIRE

    Ladislav Kolařík; Marie Kolaříková; Karel Kovanda; Marek Pantůček; Petr Vondrouš

    2012-01-01

    This paper evaluates the use of a modern welding power source equipped with advanced arc control functions. At the Laboratory of Welding Technologies of CTU in Prague we have focused on GMAW welding of steel using Sigma Galaxy, a modern welding power source produced by Migatronic. Sigma Galaxy is equipped with functions called Intelligent Arc Control and Sequence Repeat. According to the manufacturer, controlling an arc by these functions should significantly stabilize the welding process, lo...

  3. Virtual Welded-Joint Design Integrating Advanced Materials and Processing Technologies

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Z.; Dong, P.; Liu, S.; Babu, S.; Olson, G.; DebRoy, T.

    2005-04-15

    The primary goal of this project is to increase the fatigue life of a welded-joint by 10 times and to reduce energy use by 25% through product performance and productivity improvements using an integrated modeling approach. The fatigue strength of a welded-joint is currently the bottleneck to design high performance and lightweight welded structures using advanced materials such as high strength steels. In order to achieve high fatigue strength in a welded-joint it is necessary to manage the weld bead shape for lower stress concentration, produce preferable residual stress distribution, and obtain the desired microstructure for improved material toughness and strength. This is a systems challenge that requires the optimization of the welding process, the welding consumable, the base material, as well as the structure design. The concept of virtual welded-joint design has been proposed and established in this project. The goal of virtual welded-joint design is to develop a thorough procedure to predict the relationship of welding process, microstructure, property, residual stress, and the ultimate weld fatigue strength by a systematic modeling approach. The systematic approach combines five sub-models: weld thermal-fluid model, weld microstructure model, weld material property model, weld residual stress model, and weld fatigue model. The systematic approach is thus based on interdisciplinary applied sciences including heat transfer, computational fluid dynamics, materials science, engineering mechanics, and material fracture mechanics. The sub-models are based on existing models with further development. The results from modeling have been validated with critical experiments. The systematic modeling approach has been used to design high fatigue resistant welds considering the combined effects of weld bead geometry, residual stress, microstructure, and material property. In particular, a special welding wire has been developed in this project to introduce

  4. Virtual Welded - Joint Design Integrating Advanced Materials and Processing Technology

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Zhishang; Ludewig, Howard W.; Babu, S. Suresh

    2005-06-30

    Virtual Welede-Joint Design, a systematic modeling approach, has been developed in this project to predict the relationship of welding process, microstructure, properties, residual stress, and the ultimate weld fatique strength. This systematic modeling approach was applied in the welding of high strength steel. A special welding wire was developed in this project to introduce compressive residual stress at weld toe. The results from both modeling and experiments demonstrated that more than 10x fatique life improvement can be acheived in high strength steel welds by the combination of compressive residual stress from the special welding wire and the desired weld bead shape from a unique welding process. The results indicate a technology breakthrough in the design of lightweight and high fatique performance welded structures using high strength steels.

  5. Overview of welding of oxide dispersion strengthened (ODS) alloys for advanced nuclear reactor applications

    International Nuclear Information System (INIS)

    Oxide dispersion strengthened (ODS) alloys are very promising materials for Generation IV reactors with a potential to be used at elevated temperatures under severe neutron exposure environment. Welding of the ODS alloys is an understudied problem. In this paper, an overview of welding of the ODS alloys useful for advanced nuclear reactor applications is presented. The microstructural changes and the resultant mechanical properties obtained by various solid state welding processes are reviewed. Based on our results on PM2000, an approach for future work on welding of the ODS alloys is suggested. (author)

  6. Towards advanced welding methods for the ITER vacuum vessel sectors

    International Nuclear Information System (INIS)

    The problem of joining the International Thermonuclear Experimental Reactor (ITER) vacuum vessel (VV) sectors, considering the tolerance requirements of the blanket attachments, and the time required for TIG welding, continues to stimulate EU R and D into power beam welding techniques which can yield fewer passes, less welding time and lower distortion. The previous work on reduced pressure e-beam welding showed that penetration varied with position, fit-up, distance and pressure and single-pass weld control was deemed to be not reliable enough so the work direction changed to an all-e-beam welding procedure where the root weld is carried out with rest-current-control and the fill passes by wire-fill. In addition, a novel method of increasing the possible single-pass weld thickness for overhead positions is investigated demonstrated and now patented. Another solution may be offered with wire-fill NdYAG laser welding, which has demonstrated useable and stable results and proved improved performance over TIG. Preliminary work has shown even further advantages with the introduction of hybrid MIG/Laser welding

  7. 'The Relation of Biology to Astronomy' and Theology: Panspermia and Panentheism; Revolutionary Convergences Advanced by Fred Hoyle and Chandra Wickramasinghe

    Science.gov (United States)

    Walker, Theodore, Jr.

    2012-06-01

    In contrast to the Copernican revolution in astro-geometry, the Hoyle-Wickramasinghe contribution to the recent and continuing revolution in astrobiology - "cometary panspermia" - features astronomy and biology converging toward theology. They employed astro-biotic reasoning (often labeled "anthropic" reasoning) to demonstrate that life is made possible by the deliberate controlling influence of the living all-embracing "intelligent universe." This is consistent with panentheism [pan-en-theos-ism, not pantheism]. As advanced by Hoyle and Wickramasinghe, cometary panspermia is panentheistic. Also, neoclassical panentheism requires generic panspermia, and favors cometary panspermia.

  8. Pore formation and its mitigation during hybrid laser/arc welding of advanced high strength steel

    International Nuclear Information System (INIS)

    Highlights: • Possible mechanisms of pores formation in HLAW of AHSS were studied. • Mitigation approaches for removing pores in AHSS welds were introduced. • Dx in HLAW and laser welding assisted with hot wire were alleviating pores. - Abstract: The possible mechanisms of the pores formation and their mitigation during the hybrid laser/arc welding (HLAW) of Advanced High Strength Steel (AHSS) were investigated. Influence of three variables (stand-off distance between the laser and the arc of gas metal arc welding (GMAW), heat input and side shielding gas) in the HLAW for reducing the presence of pores in the weld area was studied. The optimum condition of the welds prepared by the HLAW was compared with the welds made by the laser welding assisted with hot wire. The vision monitoring of the welding processes was performed by a charged coupled device (CCD) camera and mechanical properties of the welds were evaluated by a high energy impact test and microhardness measurement. The joints were characterized by the scanning electron microscopy (SEM) analysis and energy dispersive X-ray spectroscopy (EDS) analysis. The results showed that the optimum stand-off distance between the laser and the tip of wire in the HLAW and laser welding assisted with a hot wire were the most effective approaches for avoiding the pore formation. The fracture surface of the welds was mostly dominated by a brittle fracture with the presence of two types of pores, indicating that there were two mechanisms for the generation of pores in the weld area

  9. Finite element process modelling of inertia friction welding advanced nickel-based superalloy

    International Nuclear Information System (INIS)

    A sequentially coupled thermal and mechanical finite element (FE) model has been developed to describe inertia friction welding (IFW) using the DEFORM 8.2 package. All modelling and experimental work was undertaken on inertia friction welds made from RR1000, which is an advanced high γ' content nickel-based superalloy. The accuracy of the thermal predictions has been assessed by an analysis of γ' distribution across the weld region as compared to those recorded during prescribed thermal simulations, while the mechanical model has been validated by comparing predicted and measured upsets and weld pressures. Finally the residual stress predictions have been compared against measurements (by neutron diffraction). In all cases excellent agreement was found between predicted and experimental data. This exercise revealed that the clamping forces applied during the welding process may have a strong influence on the axial stress field. The validated model was then used to study the effect of welding pressure on material flow, thermal history and residual stresses. The work shows that with increasing weld pressure the width of the heat-affected zone (HAZ) is reduced, while the peak temperature and strain rate is increased. In addition the peak stresses in the hoop direction near the weldline were found to be largely unaffected by the weld pressure. However, for lower welding pressures a broader high tensile hoop stress region was found in accordance with the increased HAZ.

  10. Microstructure and fatigue performance of butt-welded joints in advanced high-strength steels

    International Nuclear Information System (INIS)

    This study presents a comparative analysis of the high-cycle fatigue behaviors of butt weld joints in advanced high-strength steels with different strength levels and weld bead geometry. Welded joints were made using a gas metal arc welding (GMAW) process on dual-phase steels (DP440 and DP590) and martensitic steel (MS) with tensile strengths of 440, 590, and 1500 MPa, respectively. The microstructures with the lowest hardness were found at the base metal, the sub-critical heat-affected zone (HAZ), and the fusion zone for DP440, DP590, and MS weldments, respectively. Fatigue failure of specimens without weld beads occurred at the points of lowest hardness, and fatigue life exhibited the order MS>DP590>DP440, similar to the order of lowest hardness values in each weldment. However, the introduction of high weld beads resulted in very short, similar fatigue lives for all welded joints and fracture occurred at weld toe due to the overwhelming stress concentration effect. A transition from geometry-governed fracture toward microstructure-governed fracture was investigated by varying weld bead heights

  11. Advanced Control Methods for Optimization of Arc Welding

    DEFF Research Database (Denmark)

    Thomsen, J. S.

    the overall welding process; one of these factors are the ability of the welding machine to control the process. The internal control algorithms in GMAW machines are the topic of this PhD project. Basically, the internal control includes an algorithm which is able to keep the electrode at a given...

  12. Formability Analysis of Diode-Laser-Welded Tailored Blanks of Advanced High-Strength Steel Sheets

    Science.gov (United States)

    Panda, S. K.; Baltazar Hernandez, V. H.; Kuntz, M. L.; Zhou, Y.

    2009-08-01

    Currently, advances due to tailored blanking can be enhanced by the development of new grades of advanced high-strength steels (HSSs), for the further weight reduction and structural improvement of automotive components. In the present work, diode laser welds of three different grades of advanced high-strength dual-phase (DP) steel sheets (with tensile strengths of 980, 800, and 450 MPa) to high-strength low-alloy (HSLA) material were fabricated by applying the proper welding parameters. Formability in terms of Hecker’s limiting dome height (LDH), the strain distribution on the hemispherical dome surface, the weld line movement during deformation, and the load-bearing capacity during the stretch forming of these different laser-welded blanks were compared. Finite element (FE) analysis of the LDH tests of both the parent metals and laser-welded blanks was done using the commercially available software package LS-DYNA (Livermore Software Technology Corporation, Livermore, CA); the results compared well with the experimental data. It was also found that the LDH was not affected by the soft zone or weld zone properties; it decreased, however, with an increase in a nondimensional parameter, the “strength ratio” (SR). The weld line movement during stretch forming is an indication of nonuniform deformation resulting in a decrease in the LDH. In all the dissimilar weldments, fracture took place on the HSLA side, but the fracture location shifted to near the weld line (at the pole) in tailor-welded blanks (TWBs) of a higher strength ratio.

  13. Laser welding of an advanced rapidly-solidified titanium alloy

    Science.gov (United States)

    Baeslack, W. A., III; Chiang, S.; Albright, C. A.

    1990-06-01

    The laser weldability of a complex RS titanium alloy containing yttrium is investigated by evaluating comparatively the microstructures, mechanical properties, and fracture characteristics of the base metal and the rapidly solidified weld fusion zone. To prevent atmospheric contamination the specimen was enclosed in a helium-purged plastic bag during the welding process. After welding, the coupons were sectioned transverse to the laser beam direction of traverse, epoxy mounted, polished down to 0.05 micron SiO2 and etched with Kroll's reagent for examination utilizing light and SEM and energy-dispersive X-ray analysis. Results indicate that laser welding is effective in producing a fine fusion zone dispersoid structure in the RS Ti composite.

  14. Effect of oxygen on weld shape and crystallographic orientation of duplex stainless steel weld using advanced A-TIG (AA-TIG) welding method

    International Nuclear Information System (INIS)

    The double-shielded advanced A-TIG (AA-TIG) welding method was adopted in this study for the welding of the SUS329J4L duplex stainless steel with the shielding gases of different oxygen content levels. The oxygen content in the shielding gas was controlled by altering the oxygen content in the outer layer gas, while the inner layer remained pure argon to suppress oxidation on the tungsten electrode. As a result, a deep weld penetration was obtained due to the dissolution of oxygen into the weld metals. Additionally, the microstructure of the weld metal was changed by the dissolution of oxygen. The austenite phase at the ferrite grain boundary followed a Kurdjumov–Sachs (K–S) orientation relationship with the ferrite matrix phase at any oxide content. On the other hand, the orientation relationship between the intragranular austenite phase and the ferrite matrix phase exhibited different patterns under different oxygen content levels. When there was little oxide in the fusion zone, only a limited part of the intragranular austenite phase and the ferrite matrix phase followed the K–S orientation relationship. With the increase of the oxide, the correspondence of the K–S relationship increased and fit very well in the 2.5% O2 shielded sample. The investigation of this phenomenon was carried out along with the nucleation mechanisms of the intragranular austenite phases. - Highlights: • Weld penetration increased with the increase of the oxygen content. • Average diameter and number density of oxide were changed by the oxygen content. • K-S relationship of Widmanstätten austenite/ferrite wasn’t varied by oxide. • Orientation relationship of intragranular austenite/ferrite was varied by oxide

  15. Effect of oxygen on weld shape and crystallographic orientation of duplex stainless steel weld using advanced A-TIG (AA-TIG) welding method

    Energy Technology Data Exchange (ETDEWEB)

    Zou, Ying, E-mail: yingzou@jwri.osaka-u.ac.jp; Ueji, Rintaro; Fujii, Hidetoshi

    2014-05-01

    The double-shielded advanced A-TIG (AA-TIG) welding method was adopted in this study for the welding of the SUS329J4L duplex stainless steel with the shielding gases of different oxygen content levels. The oxygen content in the shielding gas was controlled by altering the oxygen content in the outer layer gas, while the inner layer remained pure argon to suppress oxidation on the tungsten electrode. As a result, a deep weld penetration was obtained due to the dissolution of oxygen into the weld metals. Additionally, the microstructure of the weld metal was changed by the dissolution of oxygen. The austenite phase at the ferrite grain boundary followed a Kurdjumov–Sachs (K–S) orientation relationship with the ferrite matrix phase at any oxide content. On the other hand, the orientation relationship between the intragranular austenite phase and the ferrite matrix phase exhibited different patterns under different oxygen content levels. When there was little oxide in the fusion zone, only a limited part of the intragranular austenite phase and the ferrite matrix phase followed the K–S orientation relationship. With the increase of the oxide, the correspondence of the K–S relationship increased and fit very well in the 2.5% O{sub 2} shielded sample. The investigation of this phenomenon was carried out along with the nucleation mechanisms of the intragranular austenite phases. - Highlights: • Weld penetration increased with the increase of the oxygen content. • Average diameter and number density of oxide were changed by the oxygen content. • K-S relationship of Widmanstätten austenite/ferrite wasn’t varied by oxide. • Orientation relationship of intragranular austenite/ferrite was varied by oxide.

  16. Thick SS316 materials TIG welding development activities towards advanced fusion reactor vacuum vessel applications

    Science.gov (United States)

    Kumar, B. Ramesh; Gangradey, R.

    2012-11-01

    Advanced fusion reactors like ITER and up coming Indian DEMO devices are having challenges in terms of their materials design and fabrication procedures. The operation of these devices is having various loads like structural, thermo-mechanical and neutron irradiation effects on major systems like vacuum vessel, divertor, magnets and blanket modules. The concept of double wall vacuum vessel (VV) is proposed in view of protecting of major reactor subsystems like super conducting magnets, diagnostic systems and other critical components from high energy 14 MeV neutrons generated from fusion plasma produced by D-T reactions. The double walled vacuum vessel is used in combination with pressurized water circulation and some special grade borated steel blocks to shield these high energy neutrons effectively. The fabrication of sub components in VV are mainly used with high thickness SS materials in range of 20 mm- 60 mm of various grades based on the required protocols. The structural components of double wall vacuum vessel uses various parts like shields, ribs, shells and diagnostic vacuum ports. These components are to be developed with various welding techniques like TIG welding, Narrow gap TIG welding, Laser welding, Hybrid TIG laser welding, Electron beam welding based on requirement. In the present paper the samples of 20 mm and 40 mm thick SS 316 materials are developed with TIG welding process and their mechanical properties characterization with Tensile, Bend tests and Impact tests are carried out. In addition Vickers hardness tests and microstructural properties of Base metal, Heat Affected Zone (HAZ) and Weld Zone are done. TIG welding application with high thick SS materials in connection with vacuum vessel requirements and involved criticalities towards welding process are highlighted.

  17. Friction Stir Spot Welding (FSSW) of Advanced High Strength Steel (AHSS)

    Energy Technology Data Exchange (ETDEWEB)

    Santella, M. L.; Hovanski, Yuri; Pan, Tsung-Yu

    2012-04-16

    Friction stir spot welding (FSSW) is applied to join advanced high strength steels (AHSS): galvannealed dual phase 780 MPa steel (DP780GA), transformation induced plasticity 780 MPa steel (TRIP780), and hot-stamped boron steel (HSBS). A low-cost Si3N4 ceramic tool was developed and used for making welds in this study instead of polycrystalline cubic boron nitride (PCBN) material used in earlier studies. FSSW has the advantages of solid-state, low-temperature process, and the ability of joining dissimilar grade of steels and thicknesses. Two different tool shoulder geometries, concave with smooth surface and convex with spiral pattern, were used in the study. Welds were made by a 2-step displacement control process with weld time of 4, 6, and 10 seconds. Static tensile lap-shear strength achieved 16.4 kN for DP780GA-HSBS and 13.2kN for TRIP780-HSBS, above the spot weld strength requirements by AWS. Nugget pull-out was the failure mode of the joint. The joining mechanism was illustrated from the cross-section micrographs. Microhardness measurement showed hardening in the upper sheet steel (DP780GA or TRIP780) in the weld, but softening of HSBS in the heat-affect zone (HAZ). The study demonstrated the feasibility of making high-strength AHSS spot welds with low-cost tools.

  18. 'FOURCRACK' - An investigation of the creep performance of advanced high alloy steel welds

    International Nuclear Information System (INIS)

    Creep failure by 'Type IV' cracking in the weld heat-affected zone (HAZ) is likely to be the life-limiting failure mechanism in high-alloy steel components for advanced power plant. A UK collaborative project, 'FOURCRACK', has therefore been carried out to investigate and compare the cross-weld creep rupture performance of several casts of the advanced steels E911, P92, and P122, and the established steel P91. The experimental matrix included both stress and temperature variations while minimising the testing required to characterise the comparative performance of different welded materials. The results clarify the interplay between weld metal and HAZ failure mechanisms, the relationships between parent material and cross-weld creep strength, and the relative merits of the alternative steels. Finally, problems which arise in the assessment of cross-weld creep test data are discussed, and recommendations put forward to address the risks of biased assessment when failure can take place in different locations within the weldment

  19. Welding IV.

    Science.gov (United States)

    Allegheny County Community Coll., Pittsburgh, PA.

    Instructional objectives and performance requirements are outlined in this course guide for Welding IV, a competency-based course in advanced arc welding offered at the Community College of Allegheny County to provide students with proficiency in: (1) single vee groove welding using code specifications established by the American Welding Society…

  20. Hybrid laser/arc welding of advanced high strength steel in different butt joint configurations

    International Nuclear Information System (INIS)

    Highlights: • Feasibility of joining thick steel by HLAW process was studied. • Design of butt joint configurations satisfied ballistic test requirement. • Heat input and microstructure were changed by groove geometry. - Abstract: An experimental procedure was developed to join thick advanced high strength steel plates by using the hybrid laser/arc welding (HLAW) process, for different butt joint configurations. The geometry of the weld groove was optimized according to the requirements of ballistic test, where the length of the softened heat affected zone should be less than 15.9 mm from the weld centerline. The cross-section of the welds was examined by microhardness test. The microstructure of welds was investigated by scanning electron microscopy and an optical microscope for further analysis of the microstructure of fusion zone and heat affected zone. It was demonstrated that by changing the geometry of groove, and increasing the stand-off distance between the laser beam and the tip of wire in gas metal arc welding (GMAW) it is possible to reduce the width of the heat affected zone and softened area while the microhardness stays within the acceptable range. It was shown that double Y-groove shape can provide the optimum condition for the stability of arc and laser. The dimensional changes of the groove geometry provided substantial impact on the amount of heat input, causing the fluctuations in the hardness of the weld as a result of phase transformation and grain size. The on-line monitoring of HLAW of the advanced high strength steel indicated the arc and laser were stable during the welding process. It was shown that less plasma plume was formed in the case where the laser was leading the arc in the HLAW, causing higher stability of the molten pool in comparison to the case where the arc was leading

  1. Welding.

    Science.gov (United States)

    Cowan, Earl; And Others

    The curriculum guide for welding instruction contains 16 units presented in six sections. Each unit is divided into the following areas, each of which is color coded: terminal objectives, specific objectives, suggested activities, and instructional materials; information sheet; transparency masters; assignment sheet; test; and test answers. The…

  2. Chocolate as a Revolutionary Beverage

    OpenAIRE

    Moats, Jean; Freeman, Rebecca

    2016-01-01

    In terms of chocolate revolutionary can mean many things, from the cultural aspect to the change in the way chocolate is prepared. In this paper revolutionary stands for the idea of change, specifically the change in chocolate beverages over time. This change can be seen especially in the variety of flavours that have been and are currently being added to chocolate. Why has there been such a change in this popular drink? What makes it revolutionary in terms of flavours. This interdisciplinary...

  3. Creep Strength of Dissimilar Welded Joints Using High B-9Cr Steel for Advanced USC Boiler

    Science.gov (United States)

    Tabuchi, Masaaki; Hongo, Hiromichi; Abe, Fujio

    2014-10-01

    The commercialization of a 973 K (700 °C) class pulverized coal power system, advanced ultra-supercritical (A-USC) pressure power generation, is the target of an ongoing research project initiated in Japan in 2008. In the A-USC boiler, Ni or Ni-Fe base alloys are used for high-temperature parts at 923 K to 973 K (650 °C to 700 °C), and advanced high-Cr ferritic steels are planned to be used at temperatures lower than 923 K (650 °C). In the dissimilar welds between Ni base alloys and high-Cr ferritic steels, Type IV failure in the heat-affected zone (HAZ) is a concern. Thus, the high B-9Cr steel developed at the National Institute for Materials Science, which has improved creep strength in weldments, is a candidate material for the Japanese A-USC boiler. In the present study, creep tests were conducted on the dissimilar welded joints between Ni base alloys and high B-9Cr steels. Microstructures and creep damage in the dissimilar welded joints were investigated. In the HAZ of the high B-9Cr steels, fine-grained microstructures were not formed and the grain size of the base metal was retained. Consequently, the creep rupture life of the dissimilar welded joints using high B-9Cr steel was 5 to 10 times longer than that of the conventional 9Cr steel welded joints at 923 K (650 °C).

  4. Hybrid laser/arc welding of advanced high strength steel to aluminum alloy by using structural transition insert

    International Nuclear Information System (INIS)

    Highlights: • A concept welding procedure was presented for joining dissimilar alloys. • Controlling of temperature improved mechanical properties. • Microstructure analysis showed presence of tempered martensite. • Optimum stand-off distance caused stability of molten pool. - Abstract: The present investigation is related to the development of the welding procedure of the hybrid laser/arc welding (HLAW) in joining thick dissimilar materials. The HLAW was applied to join aluminum alloy (AA6061) to an advanced high strength steel (AHSS) where an explosively welded transition joint, TRICLAD®, was used as an intermediate structural insert between the thick plates of the aluminum alloy and AHSS. The welds were characterized by an optical microscope, scanning electron microscope (SEM), tensile test, charged coupled device (CCD) camera, and microhardness measurement. The groove angle was optimized for the welding process based on the allowed amount of heat input along the TRICLAD® interface generated by an explosive welding. The weld was fractured in the heat affected zone of the aluminum side in the tensile test. The microhardness was shown that the temperature variation caused minor softening in the heat affected zone satisfying the requirement that the width of the softened heat affected zone in the steel side falls within 15.9 mm far away from the weld centerline. The microstructure analysis showed the presence of tempered martensite at the vicinity of the weld area, which it was a cause of softening in the heat affected zone

  5. Investigation on dissimilar laser welding of advanced high strength steel sheets for the automotive industry

    Energy Technology Data Exchange (ETDEWEB)

    Rossini, M., E-mail: matteo.rossini@unibz.it [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Spena, P. Russo, E-mail: pasquale.russospena@unibz.it [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Cortese, L., E-mail: luca.cortese@unibz.it [Faculty of Science and Technology, Free University of Bozen-Bolzano, Piazza Università 5, 39100 Bolzano (Italy); Matteis, P., E-mail: paolo.matteis@polito.it [Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy); Firrao, D., E-mail: donato.firrao@polito.it [Department of Applied Science and Technology, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino (Italy)

    2015-03-25

    To support the use of advanced high strength steels in car body design and fabrication, an investigation was carried out on dissimilar butt laser welding between TWinning Induced Plasticity (TWIP) steels, Dual Phase (DP) steels, hot stamping boron (22MnB5) steels, and TRansformation Induced Plasticity (TRIP) steels. The base materials and the weldments were fully characterized by means of metallography, microhardness, and tensile tests. Digital image analysis was also used to provide additional information on the local strain field in the joint during the tensile tests. Fractographic examination was finally performed on the fracture surfaces of the tensile samples. The dissimilar joints between the DP, 22MnB5, and TRIP steels exhibit good resistance properties. On the contrary, the dissimilar joints encompassing the TWIP steel exhibit poor mechanical strength and fail along the weld seam by intergranular fracture, probably due to presence of Mn segregations. Therefore, the laser welding of TWIP steel with other advanced high strength steels is not recommended without the use of proper metal fillers. Dissimilar laser welding of DP, TRIP and 22MnB5 combinations, on the contrary, can be a solution to assemble car body parts made of these steel grades.

  6. Investigation on dissimilar laser welding of advanced high strength steel sheets for the automotive industry

    International Nuclear Information System (INIS)

    To support the use of advanced high strength steels in car body design and fabrication, an investigation was carried out on dissimilar butt laser welding between TWinning Induced Plasticity (TWIP) steels, Dual Phase (DP) steels, hot stamping boron (22MnB5) steels, and TRansformation Induced Plasticity (TRIP) steels. The base materials and the weldments were fully characterized by means of metallography, microhardness, and tensile tests. Digital image analysis was also used to provide additional information on the local strain field in the joint during the tensile tests. Fractographic examination was finally performed on the fracture surfaces of the tensile samples. The dissimilar joints between the DP, 22MnB5, and TRIP steels exhibit good resistance properties. On the contrary, the dissimilar joints encompassing the TWIP steel exhibit poor mechanical strength and fail along the weld seam by intergranular fracture, probably due to presence of Mn segregations. Therefore, the laser welding of TWIP steel with other advanced high strength steels is not recommended without the use of proper metal fillers. Dissimilar laser welding of DP, TRIP and 22MnB5 combinations, on the contrary, can be a solution to assemble car body parts made of these steel grades

  7. ADVANCED INTEGRATION OF MULTI-SCALE MECHANICS AND WELDING PROCESS SIMULATION IN WELD INTEGRITY ASSESSMENT

    Energy Technology Data Exchange (ETDEWEB)

    Wilkowski, Gery M.; Rudland, David L.; Shim, Do-Jun; Brust, Frederick W.; Babu, Sundarsanam

    2008-06-30

    The potential to save trillions of BTU’s in energy usage and billions of dollars in cost on an annual basis based on use of higher strength steel in major oil and gas transmission pipeline construction is a compelling opportunity recognized by both the US Department of Energy (DOE). The use of high-strength steels (X100) is expected to result in energy savings across the spectrum, from manufacturing the pipe to transportation and fabrication, including welding of line pipe. Elementary examples of energy savings include more the 25 trillion BTUs saved annually based on lower energy costs to produce the thinner-walled high-strength steel pipe, with the potential for the US part of the Alaskan pipeline alone saving more than 7 trillion BTU in production and much more in transportation and assembling. Annual production, maintenance and installation of just US domestic transmission pipeline is likely to save 5 to 10 times this amount based on current planned and anticipated expansions of oil and gas lines in North America. Among the most important conclusions from these studies were: • While computational weld models to predict residual stress and distortions are well-established and accurate, related microstructure models need improvement. • Fracture Initiation Transition Temperature (FITT) Master Curve properly predicts surface-cracked pipe brittle-to-ductile initiation temperature. It has value in developing Codes and Standards to better correlate full-scale behavior from either CTOD or Charpy test results with the proper temperature shifts from the FITT master curve method. • For stress-based flaw evaluation criteria, the new circumferentially cracked pipe limit-load solution in the 2007 API 1104 Appendix A approach is overly conservative by a factor of 4/π, which has additional implications. . • For strain-based design of girth weld defects, the hoop stress effect is the most significant parameter impacting CTOD-driving force and can increase the crack

  8. Automated welding of appendages on empty clad tubes: an advanced technique

    International Nuclear Information System (INIS)

    Several developments have been carried out at Atomic Fuels Division related to fabrication of PHWR fuel assemblies. This paper describes the salient features of an automated welding equipment and its design. Special attention was given to ensure integration of equipment in the existing assembly lines with ease. Detailed drawings are made using Autocad-12 and isometric view of the assembly was prepared. The equipment design is a significant step in the advancement of PHWR fuel assembly fabrication

  9. Process Optimization of Dual-Laser Beam Welding of Advanced Al-Li Alloys Through Hot Cracking Susceptibility Modeling

    Science.gov (United States)

    Tian, Yingtao; Robson, Joseph D.; Riekehr, Stefan; Kashaev, Nikolai; Wang, Li; Lowe, Tristan; Karanika, Alexandra

    2016-07-01

    Laser welding of advanced Al-Li alloys has been developed to meet the increasing demand for light-weight and high-strength aerospace structures. However, welding of high-strength Al-Li alloys can be problematic due to the tendency for hot cracking. Finding suitable welding parameters and filler material for this combination currently requires extensive and costly trial and error experimentation. The present work describes a novel coupled model to predict hot crack susceptibility (HCS) in Al-Li welds. Such a model can be used to shortcut the weld development process. The coupled model combines finite element process simulation with a two-level HCS model. The finite element process model predicts thermal field data for the subsequent HCS hot cracking prediction. The model can be used to predict the influences of filler wire composition and welding parameters on HCS. The modeling results have been validated by comparing predictions with results from fully instrumented laser welds performed under a range of process parameters and analyzed using high-resolution X-ray tomography to identify weld defects. It is shown that the model is capable of accurately predicting the thermal field around the weld and the trend of HCS as a function of process parameters.

  10. Development and evaluation of SUS 304H — IN 617 welds for advanced ultra supercritical boiler applications

    Energy Technology Data Exchange (ETDEWEB)

    Pavan, A.H.V., E-mail: pavanahv@bhelrnd.co.in [Metallurgy Department, Corporate R& D Division, Bharat Heavy Electricals Limited, Vikasnagar, Hyderabad 500 093 (India); Vikrant, K.S.N., E-mail: vikrant@bhelrnd.co.in [Metallurgy Department, Corporate R& D Division, Bharat Heavy Electricals Limited, Vikasnagar, Hyderabad 500 093 (India); Ravibharath, R., E-mail: rrbharath@bhelrnd.co.in [Welding Research Institute, Bharat Heavy Electricals Limited, Tiruchirapalli 620 014 (India); Singh, Kulvir, E-mail: kulvir@bhelrnd.co.in [Metallurgy Department, Corporate R& D Division, Bharat Heavy Electricals Limited, Vikasnagar, Hyderabad 500 093 (India)

    2015-08-26

    At moderately high temperature sections of Advanced Ultra Super Critical (AUSC) boilers, welding of superalloys to austenitic steels is inevitable owing to economic aspects of boiler. Welding of SUS 304H and Inconel 617 (IN 617) was attempted using IN 617 filler material employing conventional Gas Tungsten Arc Welding (GTAW) process and the procedure was successfully established along with optimized welding parameters. Microstructural characterization was carried out to identify various zones on either side of the fusion boundaries. Unmixed Zone and Heat Affected Zone (HAZ) were observed towards SUS 304H fusion boundary while no distinct HAZ was observed towards IN 617 fusion boundary. Micro-hardness profiling indicated decrease in hardness at the HAZ towards SUS 304H fusion boundary. Mechanical properties evaluation at both ambient and elevated temperatures was carried out and data obtained was compared with those of base metals. The tensile strength of the cross weld specimens at high temperatures were observed to be marginally lower than that of IN 617 but significantly more than that of SUS 304H, hence, tolerable. Stress-rupture properties of the cross-weld specimens as tested in this study were found to be intermediate to the base metals’ data, thus, suitable for AUSC power plants' boiler applications. Hence, this work gives an insight into welding procedure establishment, microstructural development, variation of mechanical properties at elevated temperatures and stress-rupture properties of the dissimilar metal welds at elevated temperatures. - Highlights: • Procedure establishment & parameters optimization for fabricating defect-free welds. • Characterization of various zones formed during welding. • Mechanical properties evaluation and comparison with those of base metals. • Influence of various zones formed during welding on mechanical properties inferred. • Understanding long term behavior of welds at elevated temperatures.

  11. Development and evaluation of SUS 304H — IN 617 welds for advanced ultra supercritical boiler applications

    International Nuclear Information System (INIS)

    At moderately high temperature sections of Advanced Ultra Super Critical (AUSC) boilers, welding of superalloys to austenitic steels is inevitable owing to economic aspects of boiler. Welding of SUS 304H and Inconel 617 (IN 617) was attempted using IN 617 filler material employing conventional Gas Tungsten Arc Welding (GTAW) process and the procedure was successfully established along with optimized welding parameters. Microstructural characterization was carried out to identify various zones on either side of the fusion boundaries. Unmixed Zone and Heat Affected Zone (HAZ) were observed towards SUS 304H fusion boundary while no distinct HAZ was observed towards IN 617 fusion boundary. Micro-hardness profiling indicated decrease in hardness at the HAZ towards SUS 304H fusion boundary. Mechanical properties evaluation at both ambient and elevated temperatures was carried out and data obtained was compared with those of base metals. The tensile strength of the cross weld specimens at high temperatures were observed to be marginally lower than that of IN 617 but significantly more than that of SUS 304H, hence, tolerable. Stress-rupture properties of the cross-weld specimens as tested in this study were found to be intermediate to the base metals’ data, thus, suitable for AUSC power plants' boiler applications. Hence, this work gives an insight into welding procedure establishment, microstructural development, variation of mechanical properties at elevated temperatures and stress-rupture properties of the dissimilar metal welds at elevated temperatures. - Highlights: • Procedure establishment & parameters optimization for fabricating defect-free welds. • Characterization of various zones formed during welding. • Mechanical properties evaluation and comparison with those of base metals. • Influence of various zones formed during welding on mechanical properties inferred. • Understanding long term behavior of welds at elevated temperatures

  12. An evaluation of weldability of the spot-welded guide tube for advanced nuclear fuel (1)

    International Nuclear Information System (INIS)

    This report summarizes the weldabilities of the spot-welded SRA Zirlo thimble/sleeve and of the spot-welded RXA Zircaloy-4 tube/sleeve. The welding performance of the SRA Zircaloy-4 guide thimble and RXA Zircaloy-4 grid welded by TIG- and spot-welding methods were also evaluated in order to obtain the data in relation to the corrosion properties of welded zones in PWR primary coolant condition. Some activities for this research was successfully finished. However, the corrosion tests for prolonged period are required to accurately evaluate the welding performance of the spot-welded SRA Zirlo guide thimble/sleeve for PLUS 7

  13. Advanced nondestructive examination of the reactor vessel head penetration tube welds

    International Nuclear Information System (INIS)

    Beside a referent code examination requirements, appearance of the service induced flaws on the Reactor Vessel Head (RVH) penetration tube welds forced development of remotely operated examination tools and techniques. Several systems were developed for examination of RVH PWR type while only one system for examination of VVER - 440 type RVH has been developed by Inetec. In this article the most advanced RVH VVER - 440 type examination techniques such as ultrasonic, eddy current and visual testing techniques as well as remotely operated tool are described. (author)

  14. Evaluation of weldability of the spot-welded guide tube for advanced nuclear fuel

    International Nuclear Information System (INIS)

    The weld abilities of the spot-welded SRA Zirlo thimble/sleeve (SW ZLO S) and of the spot- welded RXA Zircaloy-4 tube/sleeve (SW Zry S) were evaluated. The welding performance of the SRA Zircaloy-4 guide thimble and RXA Zircaloy-4 grid welded by TIG-and spot-welding (TW Zry G and SW Zry G) methods were also evaluated. The SW ZLO S specimen showed higher welding strength than TW Zry G specimen. The spot-welded sample also showed a different corrosion behavior to the TIG-welded one. It would be attributed to the difference of microstructures in the both samples; the spot-welding provides very fine martensite structure whereas the TIG-welding reveals a little large Widmannstatten structure

  15. 铝及铝合金先进焊接技术%Advanced Welding Technology of Aluminum and Aluminum Alloy

    Institute of Scientific and Technical Information of China (English)

    杨芙; 吕文桂; 张文明

    2012-01-01

    The weldability of aluminum and aluminum alloy and the causes and solutions of welding defects, such as porosity, hot cracks, etc., were analyzed. The research and application of several advanced welding technology for aluminum and aluminum alloy, such as laser welding, electron beam welding, variable polarity plasma arc welding, friction stir welding, etc., were discussed. The development status and tendency for the next few years welding were simply analyzed.%分析了铝及铝合金的焊接性及其在焊接过程中易出缺陷(气孔、热裂纹等)的原因和解决措施;探讨了铝及铝合金的几种先进焊接工艺(激光焊、电子束焊、变极性等离子电弧焊、搅拌摩擦焊等)的研究现状及其应用;分析了铝及铝合金焊接技术的发展状况以及未来几年的前景.

  16. Be an Alumni Relations Revolutionary.

    Science.gov (United States)

    Bickel, Kathy

    2000-01-01

    Presents marketing guru Guy Kawasaki's seven rules for revolutionaries, and examples of alumni relations innovators who are implementing change with cutting-edge programs, services, and business practices. Rules include: "jump curves" (look for new paths); "break down barriers" (challenge roadblocks of ignorance and inertia); and "let a thousand…

  17. Nondestructive testing of welds in steam generators for advanced gas cooled reactors at Heyshamm II and Torness

    International Nuclear Information System (INIS)

    The paper concerns non-destructive testing (NDT) of welds in advanced gas cooled steam generators for Heysham II and Torness nuclear power stations. A description is given of the steam generator. The selection of NDT techniques is also outlined, including the factors considered to ascertain the viability of a technique. Examples are given of applied NDT methods which match particular fabrication processes; these include: microfocus radiography, ultrasonic testing of austenitic tube butt welds, gamma-ray isotope projection system, surface crack detection, and automated radiography. Finally, future trends in this field of NDT are highlighted. (UK)

  18. Advanced characterization techniques in understanding the roles of nickel in enhancing strength and toughness of submerged arc welding high strength low alloy steel multiple pass welds in the as-welded condition

    Science.gov (United States)

    Sham, Kin-Ling

    Striving for higher strength along with higher toughness is a constant goal in material properties. Even though nickel is known as an effective alloying element in improving the resistance of a steel to impact fracture, it is not fully understood how nickel enhances toughness. It was the goal of this work to assist and further the understanding of how nickel enhanced toughness and maintained strength in particular for high strength low alloy (HSLA) steel submerged arc welding multiple pass welds in the as-welded condition. Using advanced analytical techniques such as electron backscatter diffraction, x-ray diffraction, electron microprobe, differential scanning calorimetry, and thermodynamic modeling software, the effect of nickel was studied with nickel varying from one to five wt. pct. in increments of one wt. pct. in a specific HSLA steel submerged arc welding multiple pass weldment. The test matrix of five different nickel compositions in the as-welded and stress-relieved condition was to meet the targeted mechanical properties with a yield strength greater than or equal to 85 ksi, a ultimate tensile strength greater than or equal to 105 ksi, and a nil ductility temperature less than or equal to -140 degrees F. Mechanical testing demonstrated that nickel content of three wt. pct and greater in the as-welded condition fulfilled the targeted mechanical properties. Therefore, one, three, and five wt. pct. nickel in the as-welded condition was further studied to determine the effect of nickel on primary solidification mode, nickel solute segregation, dendrite thickness, phase transformation temperatures, effective ferrite grain size, dislocation density and strain, grain misorientation distribution, and precipitates. From one to five wt. pct nickel content in the as-welded condition, the primary solidification was shown to change from primary delta-ferrite to primary austenite. The nickel partitioning coefficient increased and dendrite/cellular thickness was

  19. Temperature and Material Flow Prediction in Friction-Stir Spot Welding of Advanced High-Strength Steel

    Science.gov (United States)

    Miles, M.; Karki, U.; Hovanski, Y.

    2014-10-01

    Friction-stir spot welding (FSSW) has been shown to be capable of joining advanced high-strength steel, with its flexibility in controlling the heat of welding and the resulting microstructure of the joint. This makes FSSW a potential alternative to resistance spot welding if tool life is sufficiently high, and if machine spindle loads are sufficiently low that the process can be implemented on an industrial robot. Robots for spot welding can typically sustain vertical loads of about 8 kN, but FSSW at tool speeds of less than 3000 rpm cause loads that are too high, in the range of 11-14 kN. Therefore, in the current work, tool speeds of 5000 rpm were employed to generate heat more quickly and to reduce welding loads to acceptable levels. Si3N4 tools were used for the welding experiments on 1.2-mm DP 980 steel. The FSSW process was modeled with a finite element approach using the Forge® software. An updated Lagrangian scheme with explicit time integration was employed to predict the flow of the sheet material, subjected to boundary conditions of a rotating tool and a fixed backing plate. Material flow was calculated from a velocity field that is two-dimensional, but heat generated by friction was computed by a novel approach, where the rotational velocity component imparted to the sheet by the tool surface was included in the thermal boundary conditions. An isotropic, viscoplastic Norton-Hoff law was used to compute the material flow stress as a function of strain, strain rate, and temperature. The model predicted welding temperatures to within 4%, and the position of the joint interface to within 10%, of the experimental results.

  20. Temperature and Material Flow Prediction in Friction-Stir Spot Welding of Advanced High-Strength Steel

    Energy Technology Data Exchange (ETDEWEB)

    Miles, Michael; Karki, U.; Hovanski, Yuri

    2014-10-01

    Friction-stir spot welding (FSSW) has been shown to be capable of joining advanced high-strength steel, with its flexibility in controlling the heat of welding and the resulting microstructure of the joint. This makes FSSW a potential alternative to resistance spot welding if tool life is sufficiently high, and if machine spindle loads are sufficiently low that the process can be implemented on an industrial robot. Robots for spot welding can typically sustain vertical loads of about 8 kN, but FSSW at tool speeds of less than 3000 rpm cause loads that are too high, in the range of 11–14 kN. Therefore, in the current work, tool speeds of 5000 rpm were employed to generate heat more quickly and to reduce welding loads to acceptable levels. Si3N4 tools were used for the welding experiments on 1.2-mm DP 980 steel. The FSSW process was modeled with a finite element approach using the Forge* software. An updated Lagrangian scheme with explicit time integration was employed to predict the flow of the sheet material, subjected to boundary conditions of a rotating tool and a fixed backing plate. Material flow was calculated from a velocity field that is two-dimensional, but heat generated by friction was computed by a novel approach, where the rotational velocity component imparted to the sheet by the tool surface was included in the thermal boundary conditions. An isotropic, viscoplastic Norton-Hoff law was used to compute the material flow stress as a function of strain, strain rate, and temperature. The model predicted welding temperatures to within percent, and the position of the joint interface to within 10 percent, of the experimental results.

  1. Advanced cutting, welding and inspection methods for vacuum vessel assembly and maintenance

    International Nuclear Information System (INIS)

    ITER requires a 316 l stainless steel, double-skinned vacuum vessel (VV), each shell being 60 mm thick. EFDA (European Fusion Development Agreement) is investigating methods to be used for performing welding and NDT during VV assembly and also cutting and re-welding for remote sector replacement, including the development of an Intersector Welding Robot (IWR) [Jones et al. This conference]. To reduce the welding time, distortions and residual stresses of conventional welding, previous work concentrated on CO2 laser welding and cutting processes [Jones et al. Proc. Symp. Fusion Technol., Marseilles, 1998]. NdYAG laser now provides the focus for welding of the rearside root and for completing the weld for overhead positions with multipass filling. Electron beam (E-beam) welding with local vacuum offers a single-pass for most of the weld depth except for overhead positions. Plasma cutting has shown the capability to contain the backside dross and preliminary work with NdYAG laser cutting has shown good results. Automated ultrasonic inspection of assembly welds will be improved by the use of a phased array probe system that can focus the beam for accurate flaw location and sizing. This paper describes the recent results of process investigations in this R and D programme, involving five European sites and forming part of the overall VV/blanket research effort [W. Daenner et al. This conference

  2. Correlation of microstructure and fracture toughness of advanced 9Cr/CrMoV dissimilarly welded joint

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Qian [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Lu, Fenggui, E-mail: Lfg119@sjtu.edu.cn [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Liu, Xia [Shanghai Turbine Plant of Shanghai Electric Power Generation Equipment Co. Ltd., Shanghai 200240 (China); Yang, Renjie [Shanghai Turbine Works Company, Shanghai 200240 (China); Cui, Haichao [Shanghai Key Laboratory of Materials Laser Processing and Modification, School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China); Gao, Yulai, E-mail: ylgao@shu.edu.cn [State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200072 (China)

    2015-06-25

    In this paper, the fracture toughness and the related microstructure characteristics of dissimilarly welded joint manufactured by advanced 9Cr and CrMoV steels were systematically investigated. The dissimilarly welded joint was fabricated by narrow gap submerged arc welding (NG-SAW) applying multi-layer and multi-pass technique. Fracture toughness, as one of the most important property to assess the reliability of welded joint, was studied for different regions including CrMoV base metal (CrMoV-BM), heat affected zone (HAZ) of CrMoV side (CrMoV-HAZ), weld metal (WM), heat affected zone of 9Cr side (9Cr-HAZ) and 9Cr base metal (9Cr-BM). It was found that the fracture toughness of CrMoV-BM, CrMoV-HAZ and WM was better than that of 9Cr-HAZ and 9Cr-BM. In order to illustrate these results, the microstructure of the whole welded joint was observed by optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM) detailedly. It was found that the fine high-temperature tempered martensite and bainite in WM, CrMoV-BM and CrMoV-HAZ contribute to the higher fracture toughness, while lower fracture toughness for 9Cr-BM and HAZ was caused by coarse tempered lath-martensite. Furthermore, the fracture morphology showed that ductile fracture occurred in WM and CrMoV side, while brittle fracture appeared in BM and HAZ of 9Cr side.

  3. Correlation of microstructure and fracture toughness of advanced 9Cr/CrMoV dissimilarly welded joint

    International Nuclear Information System (INIS)

    In this paper, the fracture toughness and the related microstructure characteristics of dissimilarly welded joint manufactured by advanced 9Cr and CrMoV steels were systematically investigated. The dissimilarly welded joint was fabricated by narrow gap submerged arc welding (NG-SAW) applying multi-layer and multi-pass technique. Fracture toughness, as one of the most important property to assess the reliability of welded joint, was studied for different regions including CrMoV base metal (CrMoV-BM), heat affected zone (HAZ) of CrMoV side (CrMoV-HAZ), weld metal (WM), heat affected zone of 9Cr side (9Cr-HAZ) and 9Cr base metal (9Cr-BM). It was found that the fracture toughness of CrMoV-BM, CrMoV-HAZ and WM was better than that of 9Cr-HAZ and 9Cr-BM. In order to illustrate these results, the microstructure of the whole welded joint was observed by optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM) detailedly. It was found that the fine high-temperature tempered martensite and bainite in WM, CrMoV-BM and CrMoV-HAZ contribute to the higher fracture toughness, while lower fracture toughness for 9Cr-BM and HAZ was caused by coarse tempered lath-martensite. Furthermore, the fracture morphology showed that ductile fracture occurred in WM and CrMoV side, while brittle fracture appeared in BM and HAZ of 9Cr side

  4. Advances of orbital gas tungsten arc welding for Brazilian space applications – experimental setup

    Directory of Open Access Journals (Sweden)

    José A. Orlowski de Garcia

    2010-08-01

    Full Text Available The present work describes details of the several steps of the technology involved for the orbital Gas Tungsten Arc Welding (GTAW process of pure commercially titanium tubes. These pieces will be used to connect the several components of the propulsion system of the China-Brazilian Satellite CBERS, and is part of the Brazilian aerospace industry development. The implantation involved the steps of environment control; cut and facing of the base metal; cleaning procedures; piece alignment; choice of the type, geometry and installation of the tungsten electrode; system for the pressure of the purge gas; manual tack welding; choice of the welding parameters; and, finally, the qualification of welding procedures. Three distinct welding programs were studied, using pulsed current with increasing speed, continuous current and pulsed current with decreasing amperage levels. The results showed that the high quality criteria required to the aerospace segment is such that usual welding operations must be carefully designed and executed. The three welding developed programs generated welds free of defects and with adequate morphology, allowing to select the condition that better fits the Brazilian aerospace segment, and to be implanted in the welding of the CBERS Satellite Propulsion System.

  5. History of Resistance Welding Oxide Dispersion Strengthened Cladding and other High Temperature Materials at Center for Advanced Energy Studies

    Energy Technology Data Exchange (ETDEWEB)

    Larry Zirker; Nathan Jerred; Dr. Indrajit Charit; James Cole

    2012-03-01

    Research proposal 08-1079, 'A Comparative Study of Welded ODS Cladding Materials for AFCI/GNEP,' was funded in 2008 under an Advanced Fuel Cycle Initiative (AFCI) Research and Development Funding Opportunity, number DE-PS07-08ID14906. Th proposal sought to conduct research on joining oxide dispersion strengthen (ODS) tubing material to a solid end plug. This document summarizes the scientific and technical progress achieved during the project, which ran from 2008 to 2011.

  6. Microstructure and Hardness Distribution of Resistance Welded Advanced High Strength Steels

    DEFF Research Database (Denmark)

    Pedersen, Kim Richardt; Harthøj, Anders; Friis, Kasper Leth;

    2008-01-01

    simulated numerically and together with the material carbon equivalent, austenization temperatures and the thermal history the simulations were used to estimate the resulting post weld hardness using the commercial FE code SORPAS. The hardness of the welds of dissimilar materials was estimated with a...

  7. Three-Sheet Spot Welding of Advanced High-Strength Steels

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Friis, Kasper Storgaard; Zhang, W.;

    2011-01-01

    The automotive industry has introduced the three-layer weld configuration, which represents new challenges compared to normal two-sheet lap welds. The process is further complicated by introducing high-strength steels in the joint. The present article investigates the weldability of thin, low...

  8. ON INTELLIGENTIZED TECHNOLOGIES FOR MODERN WELDING MANUFACTURING

    Institute of Scientific and Technical Information of China (English)

    Chen Shanben; Qiu Tao; Lin Tao; Wu Yixiong

    2003-01-01

    A short survey on researching and developing status of intelligent technologies in modem welding manufacturing is given. According to the developing trend of advanced manufacturing technology, a concept on intelligentized welding manufacturing engineering (IWME), is presented for systematization of researching and developing domains on welding automation, intelligentized welding,robotic and flexible welding and advanced welding manufacturing technologies. And key technologies of welding intelligent manufacturing and its developing trend in the future are investigated.

  9. Study on pressure resistance spot welding process of guide thimble and grid of AFA 3G advanced fuel assembly skeleton

    International Nuclear Information System (INIS)

    Skeleton spot welding is an important process of manufacturing PWR fuel assembly. In AFA 3G Skeleton spot welding, the pressure resistant spot welding technology of grid and variable thickness guide thimble is a new technical problem. By means of a lot of experiments, it is discussed in detail how different welding parameters impact on weld quality. Welding parameters impact on welding spots tensile force, welding spots diameter and welding spots corrosion performance. Analyzing and comparing with test data can get better welding parameters

  10. Advanced Engineering Methods for Assessing Welding Distortion in Aero-Engine Assemblies

    International Nuclear Information System (INIS)

    Welding remains an attractive fabrication method for aero-engine assemblies, offering high production rates and reduced total cost, particularly for large complex assemblies. However, distortion generated during the welding process continues to provide a major challenge in terms of the control of geometric tolerances and residual stress. The welding distortion is influenced by the sequence and position of joints, the clamping configuration and the design of the assembly. For large complex assemblies the range of these options may be large. Hence the use of numerical simulation at an early stage of the product development process is valuable to enable a wide range of these factors to be explored with the aim of minimising welding distortions before production commences, and thereby reducing the product development time. In this paper, a new technique for simulation of welding distortions based on a shrinkage analysis is evaluated for an aero-engine assembly. The shrinkage simulations were built and solved using the ESI Group software Weld Planner. The rapid simulation speed enabled a wide range of welding plans to be explored, leading to recommendations for the fabrication process. The sensitivity of the model to mesh size and material properties is reported. The results of the shrinkage analysis were found to be similar to those of a transient analysis generated using ESI Group software SysWeld. The solution times were found to be significantly lower for the shrinkage analysis than the transient analysis. Hence it has been demonstrated that shrinkage analysis is a valuable tool for exploring the fabrication process of a welded assembly at an early stage of the product development process.

  11. Advanced Engineering Methods for Assessing Welding Distortion in Aero-Engine Assemblies

    Science.gov (United States)

    Jackson, Kathryn; Darlington, Roger

    2011-12-01

    Welding remains an attractive fabrication method for aero-engine assemblies, offering high production rates and reduced total cost, particularly for large complex assemblies. However, distortion generated during the welding process continues to provide a major challenge in terms of the control of geometric tolerances and residual stress. The welding distortion is influenced by the sequence and position of joints, the clamping configuration and the design of the assembly. For large complex assemblies the range of these options may be large. Hence the use of numerical simulation at an early stage of the product development process is valuable to enable a wide range of these factors to be explored with the aim of minimising welding distortions before production commences, and thereby reducing the product development time. In this paper, a new technique for simulation of welding distortions based on a shrinkage analysis is evaluated for an aero-engine assembly. The shrinkage simulations were built and solved using the ESI Group software Weld Planner. The rapid simulation speed enabled a wide range of welding plans to be explored, leading to recommendations for the fabrication process. The sensitivity of the model to mesh size and material properties is reported. The results of the shrinkage analysis were found to be similar to those of a transient analysis generated using ESI Group software SysWeld. The solution times were found to be significantly lower for the shrinkage analysis than the transient analysis. Hence it has been demonstrated that shrinkage analysis is a valuable tool for exploring the fabrication process of a welded assembly at an early stage of the product development process.

  12. The revolutionary impact of evolving aeronautical technologies

    Science.gov (United States)

    Kayten, G. G.; Driver, C.; Maglieri, D. J.

    1984-01-01

    Recent advances in aeronautical technologies which could produce revolutionary changes in transport aircraft if fully implemented are delineated. Laminar flow control offers a L/D improvement from the current 18 to 22 if used with a 767 configuration. Higher aspect and thickness/chord ratios could yield more efficient structural designs and further drag reduction. High-strength, fiber-reinforced composite structures can reduce structural weight by 10-30 percent. Improved engine cooling methods, higher stage loadings and exhaust temperatures can lower the SFC by 15 percent, engine weight by 15 percent, and the parts count by 50 percent. Aft-mounted counterrotating propellers can potentially decrease the SFC an additional 15-20 percent. Supersonic transport aircraft with L/D ratios of 18 and 70 seat miles/gal fuel efficiency can now be built that weigh half as much as the Concorde and carry the same load. The new SST would have superplastic-molded Al alloy structures.

  13. Use of servo controlled weld head for end closure welding

    International Nuclear Information System (INIS)

    In the PHWR fuel fabrication line resistance welding processes are used for joining various zirconium based alloy components to fuel tube of similar material. The quality requirement of these welding processes is very stringent and has to meet all the product requirements. At present these welding processes are being carried out by using standard resistance welding machines. In the resistance welding process in addition to current and time, force is one of the critical and important parameter, which influences the weld quality. At present advanced feed back type fast response medium frequency weld controllers are being used. This has upslope/down slope, constant and repetitive weld pattern selection features makes this critical welding process more reliable. Compared to weld controllers, squeeze force application devices are limited and normally standard high response pneumatic cylinders are used in the welding process. With this type of devices the force is constant during welding process and cannot be varied during welding process as per the material deformation characteristics. Similarly due to non-availability of feed back systems in the squeeze force application systems restricts the accuracy and quality of the welding process. In the present paper the influence of squeeze force pattern on the weld quality using advanced feed back type servo based force control system was studied. Different squeeze forces were used during pre and post weld heat periods along with constant force and compared with the weld quality. (author)

  14. Advanced Approach of Reactor Pressure Vessel Head Inspection and Repair of CRDM J-Weld

    International Nuclear Information System (INIS)

    The reactor pressure vessel head (RPVH) of Pressurized Water Reactors (PWR's) is an integral part of the reactor coolant pressure boundary. Its integrity is important to the safe operation of the plant. RPVH has penetration nozzles for instrumentation systems and control rod drive mechanisms. The discovery of leaks and nozzle cracking at the US NPP and some other PWR plants has made clear the need for more effective inspections of RPV heads and associated penetration nozzles. Alloy 600 RVHP nozzles and corresponding J-welds cracking and leaking phenomena have been strictly regulated by NRC Order EA-03-009 since 2003. Some additional events on this component (Canopy Seal welds, Thermal sleeve, Control Rods Drive Mechanism...) in nuclear industry have raised concerns about the structural integrity of RPVH and consequently increased extent of Non Destructive Examination employing new state-of-the art NDE and repair methods. This article presents non destructive examination of Reactor Pressure Vessel Head (RPVH) Penetration by various methods. The scope of this examination and repair methods includes Eddy Current examination of RPVH J-weld surface, ultrasound examination of Penetration Tube from inner side and unique method of surface indications removal. These article present details of examination techniques with focus on eddy current and ultrasonic examination, as well as details and approach on AST (Automatic Surface Treatment) method of the RPVH J-weld surface. AST repair method represents new principal approach with combination of design basis justification and As-built measurements which provide to perform repair of J-weld indications without any welding.(author).

  15. Microstructure characteristics and temperature-dependent high cycle fatigue behavior of advanced 9% Cr/CrMoV dissimilarly welded joint

    International Nuclear Information System (INIS)

    Advanced 9% Cr and CrMoV steels chosen as candidate materials are first welded by narrow-gap submerged arc welding (NG-SAW) to fabricate the heavy section rotor. The present work focuses on studying the high-cycle fatigue (HCF) behavior of advanced 9% Cr/CrMoV dissimilarly welded joint at different temperatures. Conditional fatigue strength of this dissimilarly welded joint was obtained by HCF tests at room temperature (RT), 400 °C and 470 °C. It was observed that the failure occurred at the side of CrMoV base metal (BM), weld metal (WM) and heat affected zone (HAZ) of CrMoV side over 5×107 cycles for the specimens tested at RT, 400 °C and 470 °C. The detailed microstructures of BMs, WMs and HAZs as well as fracture appearance were observed by optical microscopy (OM) and scanning electron microscopy (SEM). Precipitation and aggregation of carbides along the grain boundaries were clearly detected with the increase of temperature, which brought a negative effect on the fatigue properties. It is interesting to note that the inclusion size leading to crack initiation became smaller for the HCF test at higher temperature. Therefore, reduction in the inclusion size in a welded joint helps to improve the HCF performance at high temperature

  16. Advanced examination techniques applied to the qualification of critical welds for the ITER correction coils

    CERN Document Server

    Sgobba, Stefano; Libeyre, Paul; Marcinek, Dawid Jaroslaw; Piguiet, Aline; Cécillon, Alexandre

    2015-01-01

    The ITER correction coils (CCs) consist of three sets of six coils located in between the toroidal (TF) and poloidal field (PF) magnets. The CCs rely on a Cable-in-Conduit Conductor (CICC), whose supercritical cooling at 4.5 K is provided by helium inlets and outlets. The assembly of the nozzles to the stainless steel conductor conduit includes fillet welds requiring full penetration through the thickness of the nozzle. Static and cyclic stresses have to be sustained by the inlet welds during operation. The entire volume of helium inlet and outlet welds, that are submitted to the most stringent quality levels of imperfections according to standards in force, is virtually uninspectable with sufficient resolution by conventional or computed radiography or by Ultrasonic Testing. On the other hand, X-ray computed tomography (CT) was successfully applied to inspect the full weld volume of several dozens of helium inlet qualification samples. The extensive use of CT techniques allowed a significant progress in the ...

  17. A Review: Welding Of Dissimilar Metal Alloys by Laser Beam Welding & Friction Stir Welding Techniques

    Directory of Open Access Journals (Sweden)

    Ms. Deepika Harwani

    2014-12-01

    Full Text Available Welding of dissimilar metals has attracted attention of the researchers worldwide, owing to its many advantages and challenges. There is no denial in the fact that dissimilar welded joints offer more flexibility in the design and production of the commercial and industrial components. Many welding techniques have been analyzed to join dissimilar metal combinations. The objective of this paper is to review two such techniques – Laser welding and Friction stir welding. Laser beam welding, a high power density and low energy-input process, employs a laser beam to produce welds of dissimilar materials. Friction stir welding, a solid-state joining process, is also successfully used in dissimilar welding applications like aerospace and ship building industries. This paper summarizes the trends and advances of these two welding processes in the field of dissimilar welding. Future aspects of the study are also discussed.

  18. Advances of orbital gas tungsten arc welding for Brazilian space applications – experimental setup

    OpenAIRE

    José A. Orlowski de Garcia; Nilton Souza Dias; Gérson Luiz de Lima; Wilson D. Bocallão Pereira; Nívio Fernandes Nogueira

    2010-01-01

    The present work describes details of the several steps of the technology involved for the orbital Gas Tungsten Arc Welding (GTAW) process of pure commercially titanium tubes. These pieces will be used to connect the several components of the propulsion system of the China-Brazilian Satellite CBERS, and is part of the Brazilian aerospace industry development. The implantation involved the steps of environment control; cut and facing of the base metal; cleaning procedures; piece alignment; cho...

  19. Friction Stir Welding Technology: Adapting NASA's Retractable Pin Tool

    OpenAIRE

    ECT Team, Purdue

    2007-01-01

    In late 1991, The Welding Institute (TWI), a British research and technology organization, invented and patented a welding process named Friction Stir Welding (FSW). Friction Stir Welding is a highly significant advancement in aluminum welding technology that can produce stronger, lighter, and more efficient welds than any previous process.

  20. Advanced Ultrasonic Inspection Techniques for General Purpose Heat Source Fueled Clad Closure Welds

    Energy Technology Data Exchange (ETDEWEB)

    Moyer, M.W.

    2001-01-11

    A radioisotope thermoelectric generator is used to provide a power source for long-term deep space missions. This General Purpose Heat Source (GPHS) is fabricated using iridium clad vent sets to contain the plutonium oxide fuel pellets. Integrity of the closure weld is essential to ensure containment of the plutonium. The Oak Ridge Y-12 Plant took the lead role in developing the ultrasonic inspection for the closure weld and transferring the inspection to Los Alamos National Laboratory for use in fueled clad inspection for the Cassini mission. Initially only amplitude and time-of-flight data were recorded. However, a number of benign geometric conditions produced signals that were larger than the acceptance threshold. To identify these conditions, a B-scan inspection was developed that acquired full ultrasonic waveforms. Using a test protocol the B-scan inspection was able to identify benign conditions such as weld shield fusion and internal mismatch. Tangential radiography was used to confirm the ultrasonic results. All but two of 29 fueled clads for which ultrasonic B-scan data was evaluated appeared to have signals that could be attributed to benign geometric conditions. This report describes the ultrasonic inspection developed at Y-12 for the Cassini mission.

  1. Microstructural Evolution and Creep-Rupture Behavior of Fusion Welds Involving Alloys for Advanced Ultrasupercritical Power Generation

    Science.gov (United States)

    Bechetti, Daniel H., Jr.

    Projections for large increases in the global demand for electric power produced by the burning of fossil fuels, in combination with growing environmental concerns surrounding these fuel sources, have sparked initiatives in the United States, Europe, and Asia aimed at developing a new generation of coal fired power plant, termed Advanced Ultrasupercritical (A-USC). These plants are slated to operate at higher steam temperatures and pressures than current generation plants, and in so doing will offer increased process cycle efficiency and reduced greenhouse gas emissions. Several gamma' precipitation strengthened Ni-based superalloys have been identified as candidates for the hottest sections of these plants, but the microstructural instability and poor creep behavior (compared to wrought products) of fusion welds involving these alloys present significant hurdles to their implementation and a gap in knowledge that must be addressed. In this work, creep testing and in-depth microstructural characterization have been used to provide insight into the long-term performance of these alloys. First, an investigation of the weld metal microstructural evolution as it relates to creep strength reductions in A-USC alloys INCONELRTM 740, NIMONICRTM 263 (INCONEL and NIMONIC are registered trademarks of Special Metals Corporation), and HaynesRTM 282RTM (Haynes and 282 are registered trademarks of Haynes International) was performed. gamma'-precipitate free zones were identified in two of these three alloys, and their development was linked to the evolution of phases that precipitate at the expense of gamma'. Alloy 282 was shown to avoid precipitate free zone formation because the precipitates that form during long term aging in this alloy are poor in the gamma'-forming elements. Next, the microstructural evolution of INCONELRTM 740H (a compositional variant of alloy 740) during creep was investigated. Gleeble-based interrupted creep and creep-rupture testing was used to

  2. Acoustic emission measurements of PWR weld material with inserted defects using advanced instrumentation

    International Nuclear Information System (INIS)

    Twenty-one steel tensile specimens containing realistic welding defects have been monitored for acoustic emission during loading to failure. A new design of broad frequency bandwidth point contact transducer was used and the resulting signal captured using a high speed transient recording system. The data was analysed using the techniques of statistical pattern recognition to separate different types of signals. The results show that it is possible to separate true acoustic emission from background noise and to distinguish between certain types of defect. (author)

  3. Simulation of welding

    Institute of Scientific and Technical Information of China (English)

    Chuan-Song WU; Michael RETHMEIER; Christopher SCHWENK

    2011-01-01

    @@ Welding has become the most important materials processing technology in manufacturing, and has critical effects on the quality, reliability and life of products as well as production cost, efficiency and response speed to market.As various kinds of high performance metallic materials are widely used in engineering, there are more demands in manufacturing industry for advanced welding technology.

  4. Assessment of Crack Detection in Heavy-Walled Cast Stainless Steel Piping Welds Using Advanced Low-Frequency Ultrasonic Methods

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Michael T.; Crawford, Susan L.; Cumblidge, Stephen E.; Denslow, Kayte M.; Diaz, Aaron A.; Doctor, Steven R.

    2007-03-01

    Studies conducted at the Pacific Northwest National Laboratory in Richland, Washington, have focused on assessing the effectiveness and reliability of novel approaches to nondestructive examination (NDE) for inspecting coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the U.S. Nuclear Regulatory Commission on the effectiveness and reliability of advanced NDE methods as related to the inservice inspection of safety-related components in pressurized water reactors (PWRs). This report provides progress, recent developments, and results from an assessment of low frequency ultrasonic testing (UT) for detection of inside surface-breaking cracks in cast stainless steel reactor piping weldments as applied from the outside surface of the components. Vintage centrifugally cast stainless steel piping segments were examined to assess the capability of low-frequency UT to adequately penetrate challenging microstructures and determine acoustic propagation limitations or conditions that may interfere with reliable flaw detection. In addition, welded specimens containing mechanical and thermal fatigue cracks were examined. The specimens were fabricated using vintage centrifugally cast and statically cast stainless steel materials, which are typical of configurations installed in PWR primary coolant circuits. Ultrasonic studies on the vintage centrifugally cast stainless steel piping segments were conducted with a 400-kHz synthetic aperture focusing technique and phased array technology applied at 500 kHz, 750 kHz, and 1.0 MHz. Flaw detection and characterization on the welded specimens was performed with the phased array method operating at the frequencies stated above. This report documents the methodologies used and provides results from laboratory studies to assess baseline material noise, crack detection, and length-sizing capability for low-frequency UT in cast stainless steel piping.

  5. Assessment of Crack Detection in Heavy-Walled Cast Stainless Steel Piping Welds Using Advanced Low-Frequency Ultrasonic Methods

    International Nuclear Information System (INIS)

    Studies conducted at the Pacific Northwest National Laboratory in Richland, Washington, have focused on assessing the effectiveness and reliability of novel approaches to nondestructive examination (NDE) for inspecting coarse-grained, cast stainless steel reactor components. The primary objective of this work is to provide information to the U.S. Nuclear Regulatory Commission on the effectiveness and reliability of advanced NDE methods as related to the inservice inspection of safety-related components in pressurized water reactors (PWRs). This report provides progress, recent developments, and results from an assessment of low frequency ultrasonic testing (UT) for detection of inside surface-breaking cracks in cast stainless steel reactor piping weldments as applied from the outside surface of the components. Vintage centrifugally cast stainless steel piping segments were examined to assess the capability of low-frequency UT to adequately penetrate challenging microstructures and determine acoustic propagation limitations or conditions that may interfere with reliable flaw detection. In addition, welded specimens containing mechanical and thermal fatigue cracks were examined. The specimens were fabricated using vintage centrifugally cast and statically cast stainless steel materials, which are typical of configurations installed in PWR primary coolant circuits. Ultrasonic studies on the vintage centrifugally cast stainless steel piping segments were conducted with a 400-kHz synthetic aperture focusing technique and phased array technology applied at 500 kHz, 750 kHz, and 1.0 MHz. Flaw detection and characterization on the welded specimens was performed with the phased array method operating at the frequencies stated above. This report documents the methodologies used and provides results from laboratory studies to assess baseline material noise, crack detection, and length-sizing capability for low-frequency UT in cast stainless steel piping

  6. Robot welding process control

    Science.gov (United States)

    Romine, Peter L.

    1991-01-01

    This final report documents the development and installation of software and hardware for Robotic Welding Process Control. Primary emphasis is on serial communications between the CYRO 750 robotic welder, Heurikon minicomputer running Hunter & Ready VRTX, and an IBM PC/AT, for offline programming and control and closed-loop welding control. The requirements for completion of the implementation of the Rocketdyne weld tracking control are discussed. The procedure for downloading programs from the Intergraph, over the network, is discussed. Conclusions are made on the results of this task, and recommendations are made for efficient implementation of communications, weld process control development, and advanced process control procedures using the Heurikon.

  7. Revolutionaries and spies on trees and unicyclic graphs

    CERN Document Server

    Cranston, Daniel W; West, Douglas B

    2011-01-01

    A team of $r$ {\\it revolutionaries} and a team of $s$ {\\it spies} play a game on a graph $G$. Initially, revolutionaries and then spies take positions at vertices. In each subsequent round, each revolutionary may move to an adjacent vertex or not move, and then each spy has the same option. The revolutionaries want to hold an {\\it unguarded meeting}, meaning $m$ revolutionaries at some vertex having no spy at the end of a round. To prevent this forever, trivially at least $\\min\\{|V(G)|,\\FL{r/m}\\}$ spies are needed. When $G$ is a tree, this many spies suffices. When $G$ is a unicyclic graph, $\\min\\{|V(G)|,\\CL{r/m}\\}$ spies suffice, and we characterize those unicyclic graphs where $\\FL{r/m}+1$ spies are needed. \\def\\FL#1{\\lfloor #1 \\rfloor} \\def\\CL#1{\\lceil #1 \\rceil}

  8. Friction stir welding of copper alloys

    Institute of Scientific and Technical Information of China (English)

    Liu Shuhua; Liu Meng; Wang Deqing; Xu Zhenyue

    2007-01-01

    Copper plates,brass plates and copper/brass plates were friction stir welded with various parameters. Experimental results show that the microstructure of the weld is characterized by its much finer grains as contrasted with the coarse grains of parent materials and the heat-affected zones are very narrow. The microhardness of the copper weld is a little higher than that of parent plate. The microhardness of brass weld is about 25% higher than that of parent material. The tensile strength of copper joints increases with increasing welding speed in the test range. The range of parameters to obtain good welds for copper is much wider than that for brass. When different materials were welded, the position of copper plate before welding affected the quality of FSW joints. If the copper plate was put on the advancing side of weld, the good quality of weld could be got under proper parameters.

  9. Welding Curriculum.

    Science.gov (United States)

    Alaska State Dept. of Education, Juneau. Div. of Adult and Vocational Education.

    This competency-based curriculum guide is a handbook for the development of welding trade programs. Based on a survey of Alaskan welding employers, it includes all competencies a student should acquire in such a welding program. The handbook stresses the importance of understanding the principles associated with the various elements of welding.…

  10. Einstein's Revolutionary Light-Quantum Hypothesis

    International Nuclear Information System (INIS)

    Albert Einstein's light-quantum paper was the only one of his great papers of 1905 that he himself called ''very revolutionary''. I sketch his arguments for light quanta, his analysis of the photoelectric effect, and his introduction of the wave-particle duality into physics in 1909. I show that Robert Andrews Millikan, in common with almost all physicists at the time, rejected Einstein's light-quantum hypothesis as an interpretation of his photoelectric-effect experiments of 1915. I then trace the complex experimental and theoretical route that Arthur Holly Compton followed between 1916 and 1922 that led to his discovery of the Compton effect, a discovery that Peter Debye also made virtually simultaneously and independently. Compton's discovery, however, was challenged on experimental grounds by William Duane and on theoretical grounds by Niels Bohr in the Bohr-Kramers-Slater theory of 1924, and only after that theory was disproved experimentally the following year by Walther Bothe and Hans Geiger in Berlin and by Compton and Alfred W. Simon in Chicago was Einstein's light-quantum hypothesis generally accepted by physicists. (author)

  11. Revolutionary impact of nanodrug delivery on neuroscience.

    Science.gov (United States)

    Khanbabaie, Reza; Jahanshahi, Mohsen

    2012-12-01

    Brain research is the most expanding interdisciplinary research that is using the state of the art techniques to overcome limitations in order to conduct more accurate and effective experiments. Drug delivery to the target site in the central nervous system (CNS) is one of the most difficult steps in neuroscience researches and therapies. Taking advantage of the nanoscale structure of neural cells (both neurons and glia); nanodrug delivery (second generation of biotechnological products) has a potential revolutionary impact into the basic understanding, visualization and therapeutic applications of neuroscience. Current review article firstly provides an overview of preparation and characterization, purification and separation, loading and delivering of nanodrugs. Different types of nanoparticle bioproducts and a number of methods for their fabrication and delivery systems including (carbon) nanotubes are explained. In the second part, neuroscience and nervous system drugs are deeply investigated. Different mechanisms in which nanoparticles enhance the uptake and clearance of molecules form cerebrospinal fluid (CSF) are discussed. The focus is on nanodrugs that are being used or have potential to improve neural researches, diagnosis and therapy of neurodegenerative disorders. PMID:23730260

  12. Technology of Laser Welding-recent Advances of Research and Application in Aerospace%激光焊接技术研究进展及其在航天领域的应用

    Institute of Scientific and Technical Information of China (English)

    赵耀邦; 徐爱杰; 姜勇; 成群林; 李中权

    2013-01-01

      High efficient and adaptable laser welding methods, such as high power laser welding, laser-arc hybrid welding, dual beam laser welding, laser welding-brazing were summarized. The application of laser welding technology in aerospace manufacturing such as missile launcher, missile structure and rocket motor etc. were introduced. Recent advances of laser welding and its application in aerospace were comprehensively reviewed.%  综述了大功率光纤激光焊、激光-电弧复合焊、双光束激光焊、激光熔钎焊等高效、高适应激光焊接技术特点及其研究进展,介绍了激光焊接技术在导弹发射箱、导弹弹体结构、火箭发动机等航天领域的工程化应用。全面地梳理和总结了激光焊接技术研究进展及其在航天领域的应用。

  13. Welding process

    International Nuclear Information System (INIS)

    This invention relates to a process for making a large number of weld beads as separate contours, spaced out from each other, by means of an automatic welding head. Under this invention, after striking the arc in the prescribed manner and positioning the torch on the first contour to be welded and having made the first weld bead, the torch current is reduced to bring about a part fade out of the arc. The torch is then moved to the starting position on a second contour to be welded where a static timed pre-fusion is effected by resumption of the welding current to carry out the second weld bead by following the second welding contour in the same manner and so forth. The invention particularly applies to the welding of tube ends to a tube plate

  14. Hyperspectral sounding: a revolutionary advance in atmospheric remote sensing

    Science.gov (United States)

    Smith, W. L., Sr.; Revercomb, Henry E.; Zhou, Daniel K.; Huang, Hung-Lung A.

    2005-01-01

    Hyperspectral remote sounding was introduced with the High spectral resolution Interferometer Sounder (HIS) that flew on the NASA ER-2 aircraft in the mid-1980s. The results from the HIS demonstrated that high vertical resolution sounding information could be achieved using quasi-continuous spectra of the atmosphere"s radiance to space. This has led to a series of research and operational satellite instruments designed to exploit the hyperspectral resolution sounding approach. The experimental versions, the ADEOS IMG (Interferometer for the Measurement of trace Gases) and the Aqua AIRS (Atmospheric InfraRed Sounder) have already been orbited. The IASI (Infrared Atmospheric Sounding Interferometer) and the CrIS (Cross-track Infrared Sounder) instruments are soon to be orbited on the METOP and the NPP/NPOESS operational series of polar orbiting satellites, respectively. Geostationary satellite hyperspectral resolution sounding instrumentation was initiated with the experimental GIFTS (Geostationary Imaging Fourier Transform Spectrometer) instrument whose development is providing risk reduction for the next generation of operational geostationary satellite instruments (e.g., the GOES-R Hyperspectral Environmental Suite, HES). This presentation traces the evolution of the hyperspectral resolution sounding program. Intercomparisons of the different satellite instrument approaches are discussed. Experimental results from the current aircraft and experimental satellite systems are presented to demonstrate the power of the hyperspectral resolution sounding technique.

  15. Revolutionary Transformation in the Macro-Regional Modernities

    Czech Academy of Sciences Publication Activity Database

    Hrubec, Marek

    2015-01-01

    Roč. 11, č. 6 (2015), s. 79-91. ISSN 1841-0464 Institutional support: RVO:67985955 Keywords : macro-regional * modernities * revolutionary transformations * intercultural * global Subject RIV: AA - Philosophy ; Religion

  16. Revolutionary Performance For Ultra Low Reynolds Number Vehicles Project

    Data.gov (United States)

    National Aeronautics and Space Administration — An important mission for NASA is the development of revolutionary flight concepts and technology. The development of Micro unmanned air vehicles (Micro-UAVs) and...

  17. Revolutionary change in Nicaragua and El Salvador : a comparative analysis

    OpenAIRE

    Marti, Werner Johannes

    1988-01-01

    With the success of a leftist revolution in Nicaragua and a civil war against a strong revolutionary movement in El Salvador, Central America has become one of the flash points of world politics. The two revolutionary movements, which adhere to similar ideologies, emerged in countries with similar historical roots and similar socio-economic background. This thesis analyzes the question why the Nicaraguan revolution was successful after one and a half years of general insurrection,...

  18. Steel welding.

    OpenAIRE

    Kučera, Marek

    2011-01-01

    Topic of the thesis concerns the problem of steel welding. The aim was to give acomprehensive overview on the topic, describe the known methods, advantages and disadvantages of welding technology. The introductory part is focused on introducing the basics of the process required to produce high-quality connections. Chapter three offers an overview of known and used welding methods with thein brief description of the method. The next chapter describes steel as material suitable for welding....

  19. Welding Technician

    Science.gov (United States)

    Smith, Ken

    2009-01-01

    About 95% of all manufactured goods in this country are welded or joined in some way. These welded products range in nature from bicycle handlebars and skyscrapers to bridges and race cars. The author discusses what students need to know about careers for welding technicians--wages, responsibilities, skills needed, career advancement…

  20. DOW AGROSCIENCES TODAY AND NEW REVOLUTIONARY SOLUTIONS

    Directory of Open Access Journals (Sweden)

    Slavko Vujević

    2008-09-01

    Full Text Available Dow AgroSciences LLC, based in Indianapolis, Indiana, USA, is a top tier agricultural company providing innovative crop protection, pest and vegetation management, seed, and agricultural biotechnology solutions to serve the world's growing population. Global sales for Dow AgroSciences, a wholly owned subsidiary of The Dow Chemical Company, are $3.8 billion. The company's roots in the agricultural marketplace date back to 1950 as the agricultural unit of The Dow Chemical Company and as part of Eli Lilly and Company's agricultural business. In 1989, the DowElanco joint venture was formed, and the company continued to develop new products and acquire strategic businesses. DowElanco acquired majority ownership in Mycogen Seeds in 1996; in 1997, The Dow Chemical Company acquired 100 percent of DowElanco and the company was renamed Dow AgroSciences. Other significant acquisitions include acetochlor herbicide, Cargill Hybrid Seeds, several Brazilian seed companies and the agricultural chemicals business of Rohm and Haas. Dow AgroSciences is positioned for the future through focused implementation of its strategy which revolves around productivity, portfolio management and innovation. This focus allows the company to grow through an ambitious innovation program that maximizes the products being sold today and creates new, revolutionary solutions that will surprise customers in the future. D Dow AgroSciences is committed to sustainable chemistry and has a competitive advantage in our natural products discovery capability. We've won a prestigious award for technical innovation incorporating "green" chemistry principles into chemical design, manufacture and use. Dow AgroSciences offers a full range of seeds for corn, sunflowers, canola, cotton, soybeans and alfalfa. In addition, we have developed seeds specifically bred for nutritional quality. Dow AgroSciences uses conventional breeding techniques and tools of biotechnology to produce oils that are low in

  1. Resistance welding

    DEFF Research Database (Denmark)

    Bay, Niels; Zhang, Wenqi; Rasmussen, Mogens H.;

    2003-01-01

    Resistance welding comprises not only the well known spot welding process but also more complex projection welding operations, where excessive plastic deformation of the weld point may occur. This enables the production of complex geometries and material combinations, which are often not possible...... to weld by traditional spot welding operations. Such joining processes are, however, not simple to develop due to the large number of parameters involved. Development has traditionally been carried out by large experimental investigations, but the development of a numerical programme system has...... changed this enabling prediction of the welding performance in details. The paper describes the programme in short and gives examples on industrial applications. Finally investigations of causes for failure in a complex industrial joint of two dissimilar metals are carried out combining numerical...

  2. Twenty years of revolutionary democratic Ethiopia, 1991 to 2011

    DEFF Research Database (Denmark)

    Hagmann, Tobias; Abbink, Jon

    2011-01-01

    This paper introduces a special issue of the Journal of Eastern African Studies devoted to a review of Ethiopia's 20 years of “revolutionary democracy”. The collection brings together 11 articles exploring differing aspects of Ethiopia's political experience since 1991. This introduction begins...... with a short summary of these 11 papers, but then moves to a substantive review of Ethiopia's political history over the past two decades, featuring consideration of the extent of transformation and continuity under the ruling Ethiopian Peoples' Revolutionary Democratic Front (EPRDF), the importance of...

  3. Upgraded HFIR Fuel Element Welding System

    Energy Technology Data Exchange (ETDEWEB)

    Sease, John D [ORNL

    2010-02-01

    The welding of aluminum-clad fuel plates into aluminum alloy 6061 side plate tubing is a unique design feature of the High Flux Isotope Reactor (HFIR) fuel assemblies as 101 full-penetration circumferential gas metal arc welds (GMAW) are required in the fabrication of each assembly. In a HFIR fuel assembly, 540 aluminum-clad fuel plates are assembled into two nested annular fuel elements 610 mm (24-inches) long. The welding process for the HFIR fuel elements was developed in the early 1960 s and about 450 HFIR fuel assemblies have been successfully welded using the GMAW process qualified in the 1960 s. In recent years because of the degradation of the electronic and mechanical components in the old HFIR welding system, reportable defects in plate attachment or adapter welds have been present in almost all completed fuel assemblies. In October 2008, a contract was awarded to AMET, Inc., of Rexburg, Idaho, to replace the old welding equipment with standard commercially available welding components to the maximum extent possible while maintaining the qualified HFIR welding process. The upgraded HFIR welding system represents a major improvement in the welding system used in welding HFIR fuel elements for the previous 40 years. In this upgrade, the new inner GMAW torch is a significant advancement over the original inner GMAW torch previously used. The innovative breakthrough in the new inner welding torch design is the way the direction of the cast in the 0.762 mm (0.030-inch) diameter aluminum weld wire is changed so that the weld wire emerging from the contact tip is straight in the plane perpendicular to the welding direction without creating any significant drag resistance in the feeding of the weld wire.

  4. Soldadura (Welding). Spanish Translations for Welding.

    Science.gov (United States)

    Hohhertz, Durwin

    Thirty transparency masters with Spanish subtitles for key words are provided for a welding/general mechanical repair course. The transparency masters are on such topics as oxyacetylene welding; oxyacetylene welding equipment; welding safety; different types of welds; braze welding; cutting torches; cutting with a torch; protective equipment; arc…

  5. Revolutionary Database Technology for Data Intensive Research

    OpenAIRE

    2012-01-01

    The ability to explore huge digital resources assembled in data warehouses, databases and files, at unprecedented speed, is becoming the driver of progress in science. However, existing database management systems (DBMS) are far from capable of meeting the scientists' requirements. The Database Architectures group at CWI in Amsterdam cooperates with astronomers, seismologists and other domain experts to tackle this challenge by advancing all aspects of database technology. The group’s researc...

  6. WELDING TORCH

    Science.gov (United States)

    Correy, T.B.

    1961-10-01

    A welding torch into which water and inert gas are piped separately for cooling and for providing a suitable gaseous atmosphere is described. A welding electrode is clamped in the torch by a removable collet sleeve and a removable collet head. Replacement of the sleeve and head with larger or smaller sleeve and head permits a larger or smaller welding electrode to be substituted on the torch. (AEC)

  7. Virginia Tech's "Liberty" Wins NASA's Revolutionary Vehicles Competition

    OpenAIRE

    Crumbley, Liz

    2003-01-01

    "The Liberty"--an electrically powered, hydrogen-fueled, twin-prop, corporate air taxi aircraft designed by undergraduate aerospace and industrial engineering students from Virginia Tech and Loughborough University in the United Kingdom--has won first place in the NASA Revolutionary Vehicles Concepts and Systems Competition.

  8. American Reading Instruction: Pre-Revolutionary Religious Influences.

    Science.gov (United States)

    Reutzel, Douglas Ray

    To provide some understanding of current reading methodology, this paper traces the history of reading instruction from ancient times to pre-Revolutionary America and examines the influences exerted upon that instruction by religion. The major portion of the paper discusses the cultures, religions, and educational systems of ancient Egypt;…

  9. WELDING METHOD

    Science.gov (United States)

    Cornell, A.A.; Dunbar, J.V.; Ruffner, J.H.

    1959-09-29

    A semi-automatic method is described for the weld joining of pipes and fittings which utilizes the inert gasshielded consumable electrode electric arc welding technique, comprising laying down the root pass at a first peripheral velocity and thereafter laying down the filler passes over the root pass necessary to complete the weld by revolving the pipes and fittings at a second peripheral velocity different from the first peripheral velocity, maintaining the welding head in a fixed position as to the specific direction of revolution, while the longitudinal axis of the welding head is disposed angularly in the direction of revolution at amounts between twenty minutas and about four degrees from the first position.

  10. A Recent Welding Technique: Laser Welding

    OpenAIRE

    ATİK, Dt.Ezgi; CİĞER, Prof. Dr. Semra

    2013-01-01

    Welding is a process that joins two adjacent metal surfaces with or without using filling material. The latest laser welding technique is a technology based on using infrared light spectrum. Laser welding has numerous advantages considering other conventional welding options used in dentistry and because of these reasons laser welding is used widely. When searching the literature in concern with laser welding, it is observed that this technique is compared with other conventional welding meth...

  11. Periodontio-integrated implants: A revolutionary concept

    Directory of Open Access Journals (Sweden)

    Minkle Gulati

    2014-01-01

    Full Text Available Though the fields of regenerative dentistry and tissue engineering have undergone significant advancements, yet its application to the field of implant-dentistry is lacking; in the sense that presently the implants are being placed with the aim of attaining osseointegration without giving consideration to the regeneration of periodontium around the implant. The following article reveals the clinical benefits of such periodontio-integrated implants and reviews the relevant scientific proofs. A comprehensive research to provide scientific evidence supporting the feasibility of periodontio-integrated implants was carried out using various online resources such as PubMed, Wiley-Blackwell, Elsevier etc., to retrieve studies published between 1980 and 2012 using the following key words: "implant," "tissue engineering," "periodontium," "osseo-integration," "osseoperception," "regeneration" (and their synonyms and it was found that in the past three decades, several successful experiments have been conducted to devise "implant supported by the periodontium"that can maintain form, function and potential proprioceptive responses similar to a natural tooth. Based on these staunch evidences, the possibility of the future clinical use of such implant can be strongly stated which would revolutionize the implant dentistry and will be favored by the patients as well. However, further studies are required to validate the same.

  12. High quality, high efficiency welding technology for nuclear power plants

    International Nuclear Information System (INIS)

    For nuclear power plants, it is required to ensure the safety under the high reliability and to attain the high rate of operation. In the manufacture and installation of the machinery and equipment, the welding techniques which become the basis exert large influence to them. For the purpose of improving joint performance and excluding human errors, welding heat input and the number of passes have been reduced, the automation of welding has been advanced, and at present, narrow gap arc welding and high energy density welding such as electron beam welding and laser welding have been put to practical use. Also in the welding of pipings, automatic gas metal arc welding is employed. As for the welding of main machinery and equipment, there are the welding of the joints that constitute pressure boundaries, the build-up welding on the internal surfaces of pressure vessels for separating primary water from them, and the sealing welding of heating tubes and tube plates in steam generators. These weldings are explained. The welding of pipings and the state of development and application of new welding methods are reported. (K.I.)

  13. Marc Antrop - a revolutionary transdisciplinary scientist or a traditional geographer?

    DEFF Research Database (Denmark)

    Brandt, Jesper

    2009-01-01

    Marc Antrop - a revolutionary transdisciplinary scientist or a traditional geographer? Jesper Brandt, Department of Environmental, Social and Spatial. Change (ENSPAC), Roskilde University, Denmark Few peoples might consider Marc Antrop to be a radical revolutionary. Within his academic life he...... certainly is: always at the edge of the disciplines, where the battles of scientific development and cooperation for the solution of practical problems of the real world are fighted. He has been an outstanding and vigorous fighter for integration in landscape research. Somebody might find this as a surprise...... Europe. Each of these scientific communities developed strongly but separately in the 60ties and 70ties during the cold war.  But it was also due to RUC's landscape ecological research, taking advantage of the special possibilities at this new university, fulfilling many of the expectations...

  14. Postanarchism and space: Revolutionary fantasies and autonomous zones

    OpenAIRE

    Newman, Saul

    2011-01-01

    In this paper, I call for a re-consideration of anarchism and its alternative ways of conceptualising spaces for radical politics. Here I apply a Lacanian analysis of the social imaginary to explore the utopian fantasies and desires that underpin social spaces, discourses and practices – including planning, and revolutionary politics. I will go on to develop – via Castoriadis and others – a distinctly post-anarchist conception of political space based around the project of autonomy and the...

  15. Revolutionary new drive design for Rubber Tired Gantry's

    OpenAIRE

    Kuilboer, R.

    2006-01-01

    Reductions in emissions, noise and operating costs are becoming more and more important in the ports and shipping industry. The nature of the business calls for high power demands, so potential savings are high as well. Rising oil prices and environmental concerns have triggered a huge demand for more economically sound and environmentally friendly container handling equipment. Siemens Cranes and APM Terminals have jointly developed a revolutionary Rubber Tired Gantry’s (RTG's) drive system. ...

  16. The normalization of sexual diversity in revolutionary Cuba

    OpenAIRE

    Kirk, Emily J.

    2015-01-01

    Cuba, once understood to be a highly homophobic country, has been lauded internationally for its attention to sexual diversity rights since 2008. This Thesis examines and analyzes the development of the normalization of attitudes towards sexual diversity in revolutionary Cuba. This includes the evolution of homophobia in Cuba, the Federation of Cuban Women’s development of sexual education, the establishment of the Nation Centre for Sexual Education (CENESEX), and how these elements engage wi...

  17. Tubing weld cracking test

    International Nuclear Information System (INIS)

    A tubing weld cracking (TWC) test was developed for applications involving advanced austenitic alloys (such as modified 800H and 310HCbN). Compared to the Finger hot cracking test, the TWC test shows an enhanced ability to evaluate the crack sensitivity of tubing materials. The TWC test can evaluate the cracking tendency of base as well as filter materials. Thus, it is a useful tool for tubing suppliers, filler metal producers and fabricators

  18. Welding robots

    OpenAIRE

    Pires, J. Norberto; Loureiro, Altino; Godinho, T.; Ferreira, P; Fernando, B; Morgado, J

    2003-01-01

    Using robots in industrial welding operations is common but far from being a streamlined technological process. The problems are with the robots, still in their early design stages and difficult to use and program by regular operators; the welding process, which is complex and not really well known and the human-machine interfaces, which are unnatural and not really working. In this article, these problems are discussed, and a system designed with the double objective of serving R&D efforts o...

  19. Syllabus in Trade Welding.

    Science.gov (United States)

    New York State Education Dept., Albany. Bureau of Secondary Curriculum Development.

    The syllabus outlines material for a course two academic years in length (minimum two and one-half hours daily experience) leading to entry-level occupational ability in several welding trade areas. Fourteen units covering are welding, gas welding, oxyacetylene welding, cutting, nonfusion processes, inert gas shielded-arc welding, welding cast…

  20. Differences between Laser and Arc Welding of HSS Steels

    Science.gov (United States)

    Němeček, Stanislav; Mužík, Tomáš; Míšek, Michal

    Conventional welding processes often fail to provide adequate joints in high strength steels with multiphase microstructures. One of the promising techniques is laser beam welding: working without filler metal and with sufficient capacity for automotive and transportation industry (where the amount of AHSS steels increases each year, as well as the length of laser welds). The paper compares microstructures and properties of HSS (high strength steel) joints made by MAG (Metal Active Gas) and laser welding. The effects of main welding parameters (heat input, welding speed and others) are studied on multiphase TRIP 900 steel tubes and martensitic sheets DOCOL 1200, advanced materials for seat frames and other automotive components. Whereas the strength of conventional welds is significantly impaired, laser welding leaves strength of the base material nearly unaffected. As the nature of fracture changes during loading and depending on the welding method, failure mechanisms upon cross tension tests have been studied as well.

  1. Virtual Reality Simulator Developed Welding Technology Skills

    Science.gov (United States)

    Yunus, Faizal Amin Nur; Baser, Jamil Abd; Masran, Saiful Hadi; Razali, Nizamuddin; Rahim, Bekri

    2011-01-01

    The purpose of this study was to identify the suitability of VR welding simulator application towards CBT in developing welding skills upon new trainees at the Centre of Instructor and Advanced Skills Training (CIAST) Shah Alam Selangor and National Youth Skills Institute (IKBN) Pagoh Johor. The significance of the study was to create a…

  2. Techniques for laser welding polymeric devices.

    Science.gov (United States)

    Jones, I A

    2003-04-01

    Recent advances in laser techniques mean that lasers are now being considered as an alternative to vibration, ultrasonic, dielectric, hot plate or hot bar welding, and adhesive bonding of plastics. The techniques required to put laser welding methods into practice are described for medical devices, tubular systems, films and synthetic fabrics. PMID:12789697

  3. Sensor controlled robotic welding for nuclear power plant operations

    International Nuclear Information System (INIS)

    The objective of the proposed research is to apply real time monitoring, artificial intelligence and on-line correction to dynamically control the depth of weld penetration and weld integrity during the welding process. Welding is a major technique used in the fabrication, construction and maintenance of power generating and energy conversion systems. In the welding process, fluctuations in process variables lead to weld defects such as lack of penetration, cracks, porosity and undesirable metallurgical structures. This research will apply advanced infrared sensing techniques which have been successfully used in seam tracking to the equally complex problem of weld defect and weld puddle penetration control. Thermal temperature distributions of plates being welded will be dynamically measured during welding using infrared techniques. These temperature distributions will be used to interpret changes in the size and shape of the molten metal pool and the presence of conditions that may lead to defects in the solidified weld. The ultimate result of this research will be the development of machines which are capable of sensing and altering process variables to eliminate defective welds and increase the productivity of the welding process. Successful completion of this proposed research will lead to potential major improvements in the fabrication, construction and maintenance of advanced nuclear reactors and promote increased safety and reliability while decreasing construction costs. 47 refs., 50 figs

  4. Desire and the Other in Richard Yates's Revolutionary Road

    Directory of Open Access Journals (Sweden)

    Ljubica Matek

    2011-06-01

    Full Text Available Richard Yates’s novel Revolutionary Road did not receive much academic attention despite the fact that it is an exceptionally refined and capturing piece of fiction. It was critically acclaimed following its publication in 1961, nominated for the National Book Award in 1962 and then forgotten. Not surprisingly, the novel was “rediscovered” once a movie adaptation was made in 2008. Revolutionary Road is typically read – quite expectedly – as a story of suburban malaise and a critique of the American (suburban life in the 1950s. However, in an interview, published in Ploughshares in 1972, Yates stated that although he intended the novel to be an indictment of American life in the 1950s because of a general lust for conformity (DeWitt and Clark 66, he never planned the novel to be anti-suburban in any way. On the contrary, he hoped to make it implicit in the text that he is writing about a particular couple, the Wheelers, and what turns out to be specifically “their delusion, their problem” (DeWitt and Clark 66. In that sense, the novel should be read as a psychological exploration of the universal issues of human desire and the relationship of the individual to the pre-established (social system in which he or she lives. Consequently, it becomes clear that Yates’s novel hardly represents an indictment of a way of life, but quite the opposite: an indictment of the individual unable to adapt to the demands of the Other. In Lacanian terms, Revolutionary Road is a story about the unattainable desire to create one’s identity regardless or in spite of the socially constructed Symbolic order.

  5. Improving fatigue performance of rail thermite welds

    Directory of Open Access Journals (Sweden)

    Winiar L.

    2010-06-01

    Full Text Available Rail transport development offers economic and ecological interests. Nevertheless, it requires heavy investments in rolling material and infrastructure. To be competitive, this transportation means must rely on safe and reliable infrastructure, which requires optimization of all implemented techniques and structure. Rail thermite (or aluminothermic welding is widely used within the railway industry for in-track welding during re-rail and defect replacement. The process provides numerous advantages against other welding technology commonly used. Obviously, future demands on train traffic are heavier axle loads, higher train speeds and increased traffic density. Thus, a new enhanced weld should be developed to prevent accidents due to fracture of welds and to lower maintenance costs. In order to improve such assembly process, a detailed metallurgical study coupled to a thermomechanical modelling of the phenomena involved in the thermite welding process is carried out. Obtained data enables us to develop a new improved thermite weld (type A. This joint is made by modifying the routinely specified procedure (type B used in a railway rail by a standard gap alumino-thermic weld. Joints of type A and B are tested and compared. Based on experimental temperature measurements, a finite element analysis is used to calculate the thermal residual stresses induced. In the vicinity of the weld, the residual stress patterns depend on the thermal conditions during welding as it also shown by litterature [1, 2]. In parallel, X-Ray diffraction has been used to map the residual stress field that is generated in welded rail of types A and B. Their effect on fatigue crack growth in rail welds is studied. An experimental study based on fatigue tests of rails welded by conventional and improved processes adjudicates on the new advances and results will be shown.

  6. Improving fatigue performance of rail thermite welds

    Science.gov (United States)

    Jezzini-Aouad, M.; Flahaut, P.; Hariri, S.; Winiar, L.

    2010-06-01

    Rail transport development offers economic and ecological interests. Nevertheless, it requires heavy investments in rolling material and infrastructure. To be competitive, this transportation means must rely on safe and reliable infrastructure, which requires optimization of all implemented techniques and structure. Rail thermite (or aluminothermic) welding is widely used within the railway industry for in-track welding during re-rail and defect replacement. The process provides numerous advantages against other welding technology commonly used. Obviously, future demands on train traffic are heavier axle loads, higher train speeds and increased traffic density. Thus, a new enhanced weld should be developed to prevent accidents due to fracture of welds and to lower maintenance costs. In order to improve such assembly process, a detailed metallurgical study coupled to a thermomechanical modelling of the phenomena involved in the thermite welding process is carried out. Obtained data enables us to develop a new improved thermite weld (type A). This joint is made by modifying the routinely specified procedure (type B) used in a railway rail by a standard gap alumino-thermic weld. Joints of type A and B are tested and compared. Based on experimental temperature measurements, a finite element analysis is used to calculate the thermal residual stresses induced. In the vicinity of the weld, the residual stress patterns depend on the thermal conditions during welding as it also shown by litterature [1, 2]. In parallel, X-Ray diffraction has been used to map the residual stress field that is generated in welded rail of types A and B. Their effect on fatigue crack growth in rail welds is studied. An experimental study based on fatigue tests of rails welded by conventional and improved processes adjudicates on the new advances and results will be shown.

  7. Revolutionary culture experiment in Lithuania (1927-1935)

    OpenAIRE

    Raškauskas, Kęstutis

    2014-01-01

    The “Trečias frontas” journal (1930-1931) and its group have a wide historiographical layer. Nevertheless, there is a possibility to recreate wider context of the group’s activities and analyse this in the connection with activities of some artists and theatre actors. Therefore, this phenomenon could be named as the “experiment of revolutionary culture” and dated between 1927 and 1935. About twenty persons became the object of this research. Reconstruction of group members’ biographies in com...

  8. Modeling of fundamental phenomena in welds

    Energy Technology Data Exchange (ETDEWEB)

    Zacharia, T.; Vitek, J.M. [Oak Ridge National Lab., TN (United States); Goldak, J.A. [Carleton Univ., Ottawa, Ontario (Canada); DebRoy, T.A. [Pennsylvania State Univ., University Park, PA (United States); Rappaz, M. [Ecole Polytechnique Federale de Lausanne (Switzerland); Bhadeshia, H.K.D.H. [Cambridge Univ. (United Kingdom)

    1993-12-31

    Recent advances in the mathematical modeling of fundamental phenomena in welds are summarized. State-of-the-art mathematical models, advances in computational techniques, emerging high-performance computers, and experimental validation techniques have provided significant insight into the fundamental factors that control the development of the weldment. The current status and scientific issues in the areas of heat and fluid flow in welds, heat source metal interaction, solidification microstructure, and phase transformations are assessed. Future research areas of major importance for understanding the fundamental phenomena in weld behavior are identified.

  9. Pulsed TIG welding in the fabrication of nuclear components and structures

    International Nuclear Information System (INIS)

    TIG welding is an important welding technique in nuclear plant fabrication for the welding of critical components and structures where a high level of weld integrity is demanded. Whilst the process is ideally suited to precision welding, since the arc is a small intense heat source, it has proved to be somewhat intolerant to production variations in 'difficult' applications, such as tube to tube plate welding and orbital tube welding with tube in the fixed position. Whilst the problems directly associated with this intolerance (of the welding process) are less frequently observed when used manually, difficulties are experienced in fully mechanised welding operations particularly when welding to a relatively rigid approved procedure. Pulsing of the welding current was developed as a technique to achieve greater control of the behaviour of the weld pool. Instead of moving the weld pool in a continuous motion around the joint, welding was conducted intermittently in the form of overlapping spots. This technique, which offers significant advantages over continuous current welding has been exploited in nuclear fabrication for welding those components which demand a high level of weld quality. In this paper, the essential features of this technique are described and, in indicating its advantages, examples have been drawn from recent experiences on the welding of two types of joint for the Advanced Gas Cooled Reactor, a tube sheet and a butt joint in the G Position. (author)

  10. Bertolt Brecht and Roger Howard: Revolutionary Theatre and Socio-Political Worries

    Directory of Open Access Journals (Sweden)

    Akram Shalghin

    2014-10-01

    Full Text Available This paper deals with the question of revolutionary literary texts. It examines the painful, or even brutal, measures that could be taken at times when the revolutionary figures depicted in the literary texts are themselves subject to control by a party line.  While this paper shows that the noble intentions would not suffice for conducting revolutionary acts in Brecht, it also argues for the necessity of considering even tiny steps as positive historical contributions in Howard.

  11. Microstructure modeling in weld metal

    International Nuclear Information System (INIS)

    Since microstructure development in the weld metal region is controlled by various physical processes, there is a need for integrated predictive models based on fundamental principles to describe and predict the effect of these physical processes. These integrated models should be based on various tools available for modeling microstructure development in a wide variety of alloy systems and welding processes. In this paper, the principles, methodology, and future directions of modeling thermochemical reactions in liquid, solidification, and solid state transformations are discussed with some examples for low-alloy steel, stainless steel, and Ni-base superalloy. Thermochemical deoxidation reactions in liquid low-alloy steel lead to oxide inclusion formation. This inclusion formation has been modeled by combining principles of ladle metallurgy and overall transformation kinetics. The model's comparison with the experimental data and the ongoing work on coupling this inclusion model with the numerical models of heat transfer and fluid flow are discussed. Also, recent advances in theoretical and physical modeling of the solidification process are reviewed with regard to predicting the solidification modes, grain structure development, segregation effects, and nonequilibrium solidification in welds. The effects of solid state phase transformations on microstructure development and various methods of modeling these transformations are reviewed. Successful models, based on diffusion-controlled growth and plate growth theories, on microstructure development in low-alloy steel and stainless steel weld metals are outlined. This paper also addresses the importance of advanced analytical techniques to understand the solid state transformation mechanisms in welds

  12. Development of a Human and Organizational Factors (HOF) Annex for underwater welding.

    OpenAIRE

    Cullen, Shawn.

    1997-01-01

    CIVINS Recent improvements in underwater welding have led to the increased use of wet and dry hyperbaric welding within the marine construction industry. The general acceptance of underwater welding processes has been further advanced by the standardization of methods, procedures, and certification requirements provided by the American National Standards Institute (ANSI)/American Welding Society (AWS) D3.6 Specification for Underwater Welding. A dedicated effort has been made by the AWS D3...

  13. Improving Fatigue Performance of AHSS Welds

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Zhili [ORNL; Yu, Xinghua [ORNL; ERDMAN III, DONALD L [ORNL; Wang, Yanli [ORNL; Kelly, Steve [ArcelorMittal USA; Hou, Wenkao [ArcelorMittal USA; Yan, Benda [ArcelorMittal USA; Wang, Zhifeng [Colorado School of Mines, Golden; Yu, Zhenzhen [Colorado School of Mines, Golden; Liu, Stephen [Colorado School of Mines, Golden

    2015-03-01

    Reported herein is technical progress on a U.S. Department of Energy CRADA project with industry cost-share aimed at developing the technical basis and demonstrate the viability of innovative in-situ weld residual stresses mitigation technology that can substantially improve the weld fatigue performance and durability of auto-body structures. The developed technology would be costeffective and practical in high-volume vehicle production environment. Enhancing weld fatigue performance would address a critical technology gap that impedes the widespread use of advanced high-strength steels (AHSS) and other lightweight materials for auto body structure light-weighting. This means that the automotive industry can take full advantage of the AHSS in strength, durability and crashworthiness without the concern of the relatively weak weld fatigue performance. The project comprises both technological innovations in weld residual stress mitigation and due-diligence residual stress measurement and fatigue performance evaluation. Two approaches were investigated. The first one was the use of low temperature phase transformation (LTPT) weld filler wire, and the second focused on novel thermo-mechanical stress management technique. Both technical approaches have resulted in considerable improvement in fatigue lives of welded joints made of high-strength steels. Synchrotron diffraction measurement confirmed the reduction of high tensile weld residual stresses by the two weld residual stress mitigation techniques.

  14. Distortion Control during Welding

    OpenAIRE

    Akbari Pazooki, A.M.

    2014-01-01

    The local material expansion and contraction involved in welding result in permanent deformations or instability i.e., welding distortion. Considerable efforts have been made in controlling welding distortion prior to, during or after welding. Thermal Tensioning (TT) describes a group of in-situ methods to control welding distortion. In these methods local heating and/or cooling strategies are applied during welding. Additional heating and/or cooling sources can be implemented either stationa...

  15. Guiding the welding robot to the initial welding position with visual method

    Institute of Scientific and Technical Information of China (English)

    Zhu Zhenyou; Lin Tao; Chen Shanben

    2008-01-01

    Using step pattern match technology with variational resolution can recognize the position and orientation of the weld seam in the image. According to using the image segmentation method based on pattern match, not only advanced the speed and anti-jamming capability, but also captured the edge information of the weld seam and the edge of the workpiece, and the image coordinate of the initial welding position can be obtained. The matrix for hand-eye relationship of the robot can be calculated by adopting the rapid calculation method. According to the depth calculating principle with the special point matching using binocular stereovision, the initial welding position can be confirmed by calculating the middle point of the perpendicular line of two radials in the space, and the function to guide the welding robot to the initial welding position can be realized.

  16. Embrittlement of welded joints

    International Nuclear Information System (INIS)

    The structure of a weld is considered and the role of the main parts of a welded joint in the appearance of defects during welding is determined. Factors greatly affecting hot crack formation (heat removal, impurity redistribution, volume of welding bath, welding rate) are shown. Reasons for the appearance of cracks not related to crystallization process (subsequent heat treatment, plastic working, etc.) are analyzed. The process of cold cracking of welds due to hydrogen absorption and relaxation of high welding stresses, is investigated. Methods to avoid cold cracking are described. Mechanisms of weld embrittlement are considered using as examples steels and high nickel alloys. 248 refs.; 28 figs.; 2 tabs

  17. FEM model and experiments for friction stir spot welding of AA6061-T4

    OpenAIRE

    Iordachescu, Danut; Birsan, Dan; Iordachescu, Mihaela; Ocaña Moreno, Jose Luis; Porro González, Juan Antonio

    2009-01-01

    Despite significant advances in the application of FSW, as a relatively new welding technique for welding aluminium alloys, the fundamental knowledge of such thermal impact and thermomechanical processes are still not completely understood. The paper i

  18. Discussion on Integration of Welding Coordinator in Welding Quality System of KEPIC(Korea Electric Power Industry code)

    Energy Technology Data Exchange (ETDEWEB)

    Joo, Hyun-Jae; Sohn, Myoung-Sung; Cho, Kyoung-Youn; Kim, Jong-Hae [Korea Electric Association, Seoul (Korea, Republic of)

    2015-05-15

    The welding quality system of KEPIC-MQW 'Welding Qualification' referencing ASME BPVC Sec.IX, Part QW requires welding procedures and performance qualification of welder or welding operator excluding welding coordinator. It means that there is potential possibility of any problem in process of welding on nuclear power plants or shop in absence of an welding coordinator who can resolve welding troubles. Therefore, the integration of welding coordinators in the welding quality system of KEPIC can improve welding quality and enhance safety of construction and management of power plants. The introduction of welding coordinator requirement would put economic problems on manufactures for new employment and subsequent management works (eg. training) and field problems making authorized nuclear inspectors to be confused on inspection work scopes. Those predictable problems are expected to be minimized or eliminated through public hearings and/or seminars with regulatory body, the owner, and manufacturers and, most significantly, cooperation with related KEPIC committees. The revision draft was reviewed and discussed with personnel in nuclear industry by holding three workshop and public hearings from 2011 to 2012 and by having a presentation in 2014 KEPIC-Week. Industrial consensus on need for integration of welding coordinators in welding quality system of KEPIC was performed by reasons that it would improve welding quality, guarantee welding reliability, advance expertise, and help export to abroad. However, economic problems on manufacturers for new employment and subsequent management works, for example training, are predicted. Therefore, introduction in stages for minimizing industrial impact regarding manufacturer's scale and permission of utilizing external welding coordinator for small scale manufacturers are required. A new draft version of KEPIC-MQW (if possible, appendices of MQW) including requirements and directives for solving these economic

  19. Discussion on Integration of Welding Coordinator in Welding Quality System of KEPIC(Korea Electric Power Industry code)

    International Nuclear Information System (INIS)

    The welding quality system of KEPIC-MQW 'Welding Qualification' referencing ASME BPVC Sec.IX, Part QW requires welding procedures and performance qualification of welder or welding operator excluding welding coordinator. It means that there is potential possibility of any problem in process of welding on nuclear power plants or shop in absence of an welding coordinator who can resolve welding troubles. Therefore, the integration of welding coordinators in the welding quality system of KEPIC can improve welding quality and enhance safety of construction and management of power plants. The introduction of welding coordinator requirement would put economic problems on manufactures for new employment and subsequent management works (eg. training) and field problems making authorized nuclear inspectors to be confused on inspection work scopes. Those predictable problems are expected to be minimized or eliminated through public hearings and/or seminars with regulatory body, the owner, and manufacturers and, most significantly, cooperation with related KEPIC committees. The revision draft was reviewed and discussed with personnel in nuclear industry by holding three workshop and public hearings from 2011 to 2012 and by having a presentation in 2014 KEPIC-Week. Industrial consensus on need for integration of welding coordinators in welding quality system of KEPIC was performed by reasons that it would improve welding quality, guarantee welding reliability, advance expertise, and help export to abroad. However, economic problems on manufacturers for new employment and subsequent management works, for example training, are predicted. Therefore, introduction in stages for minimizing industrial impact regarding manufacturer's scale and permission of utilizing external welding coordinator for small scale manufacturers are required. A new draft version of KEPIC-MQW (if possible, appendices of MQW) including requirements and directives for solving these economic

  20. Seeds of Resistance: Towards a Revolutionary Critical Ecopedagogy

    Directory of Open Access Journals (Sweden)

    Peter McLaren

    2013-05-01

    Full Text Available The death throes of mother earth are imminent unless we decelerate the planetary ecological crisis. Critical educators, who have addressed with firm commitment topics of race, class, gender, sexuality, disability, and other social justice issues are casting their eyes to the antagonism between capitalism and nature to ask themselves how we can rationally regulate the human metabolic relation with nature. As the global power complex reduces human life and mother earth to mere production and consumption, critical revolutionary ecopedagogy is developing new, unalienated forms of selfpresence. Ecopedagogy is inspired by and inspires a new social arc, rooted in practices of ecological struggles by the working classes and the poor – an unabashedly utopian dreaming of a post-capitalist future.

  1. Revolutionary Climatology: Rings of Saturn, Ringed by Red Lightning

    Directory of Open Access Journals (Sweden)

    Sarah K. Stanley

    2016-05-01

    Full Text Available Walter Benjamin’s concept of historical materialism is considered as a practice of media archaeology invented through literary montage and photo philosophy. The Arcades Project that facilitated this new research methodology involving a mobile archive. The main case involving architectural theory considers how Benjamin redeployed Sigfried Giedion and Laszlo Moholy-Nagy’s Building in France as a media environment, drawing upon its layout design, photo illustrations and textual systems. In terms of his urban writing, a reading of ‘A Berlin Chronicle’ considers how the diagram contributes to Benjamin’s archaeological methods, as a theory to generate site writing. Benjamin’s mode of media archaeology is then employed to map the arcades architecture onto the train stations and libraries in Berlin and Paris, sites that informed The Arcades Project. The final section assembles a set of citations as ‘Revolutionary Climatology’, thought-images as flashes of red lightning.

  2. Mish mabsoota: on teaching with a camera in revolutionary Cairo†

    Directory of Open Access Journals (Sweden)

    Mark R. Westmoreland

    2015-12-01

    Full Text Available Made in the wake of the 2011 Egyptian Revolution, Inti Mabsoota? is an experimental pedagogical video project that draws upon the emerging mobile esthetics of cell phone filmmaking and public encounters with revolutionary spontaneity. Inspired by the landmark cinéma-vérité film, Chronique d'un été (1960, in which participants ask people on the streets of Paris if they are happy, several of my students at the American University in Cairo became mobile film units, asking people the same innocuous question, “Inta mabsoot?/Inti mabsoota?”—Are you happy? Are you content? This seemingly benign exercise belies a variety of conceptual and methodological frictions, which offered productive pedagogical possibilities. Drawing upon the emergent revolutionary visual culture, this student project complicated both the reductive assessments of the “Arab Spring” as a manifestation of digital democracy and the heavy-handed way that western journalism has tended to address the “Arab Street” as a volatile mob. Using an embodied visual approach allowed students to apprehend modes of lived experience that might not register as political in more normative models, but which nonetheless form the basis of how people live and experience political life. Highlighting the non-representational aspects of the encounter also foregrounds the corporeal and visceral dimensions of the students’ experience. Accordingly, the critical video methods employed elucidate the kinds of affective knowledge produced for those on screen, behind the camera, and viewing from a distance.

  3. Welding processes handbook

    CERN Document Server

    Weman, Klas

    2011-01-01

    Offers an introduction to the range of available welding technologies. This title includes chapters on individual techniques that cover principles, equipment, consumables and key quality issues. It includes material on such topics as the basics of electricity in welding, arc physics, and distortion, and the weldability of particular metals.$bThe first edition of Welding processes handbook established itself as a standard introduction and guide to the main welding technologies and their applications. This new edition has been substantially revised and extended to reflect the latest developments. After an initial introduction, the book first reviews gas welding before discussing the fundamentals of arc welding, including arc physics and power sources. It then discusses the range of arc welding techniques including TIG, plasma, MIG/MAG, MMA and submerged arc welding. Further chapters cover a range of other important welding technologies such as resistance and laser welding, as well as the use of welding techniqu...

  4. Guerilla Cuisine: a Comparison of Various Food Provisioning Methods of Revolutionary Forces in the field

    OpenAIRE

    Murphy, Diarmuid

    2016-01-01

    Revolution and food are inextricably linked. the need for food that supplies basic nutritional values to the masses has been at the heart of many political upheavals. Food supply is an important tool for gaining popular support. This paper studies provisioning within revolutionary movements with the aim of investigating the food pathway used by revolutionaries under arms.

  5. Education and Gender in Revolutionary Societies: Insights from Vietnam, Nicaragua, and Eritrea

    Science.gov (United States)

    Muller, Tanja R.

    2007-01-01

    Based on the work of Bourdieu, this paper analyses how far formal education within a revolutionary setting can act as a "strategy-generating" institution in terms of enabling women to aspire to and achieve goals they would not even have envisaged pre-revolution. In making its case, it draws on the examples of three revolutionary societies: Vietnam…

  6. Friction Stir Welding

    Science.gov (United States)

    Nunes, Arthur C., Jr.

    2008-01-01

    Friction stir welding (FSW) is a solid state welding process invented in 1991 at The Welding Institute in the United Kingdom. A weld is made in the FSW process by translating a rotating pin along a weld seam so as to stir the sides of the seam together. FSW avoids deleterious effects inherent in melting and promises to be an important welding process for any industries where welds of optimal quality are demanded. This article provides an introduction to the FSW process. The chief concern is the physical effect of the tool on the weld metal: how weld seam bonding takes place, what kind of weld structure is generated, potential problems, possible defects for example, and implications for process parameters and tool design. Weld properties are determined by structure, and the structure of friction stir welds is determined by the weld metal flow field in the vicinity of the weld tool. Metal flow in the vicinity of the weld tool is explained through a simple kinematic flow model that decomposes the flow field into three basic component flows: a uniform translation, a rotating solid cylinder, and a ring vortex encircling the tool. The flow components, superposed to construct the flow model, can be related to particular aspects of weld process parameters and tool design; they provide a bridge to an understanding of a complex-at-first-glance weld structure. Torques and forces are also discussed. Some simple mathematical models of structural aspects, torques, and forces are included.

  7. Welding and cutting '93. Lectures

    International Nuclear Information System (INIS)

    This volume contains 46 lectures on the following ten groups of subjects: New knowledge and experience for welding firms; European welding process testing; welding developments in Europe - process and equipment; progress in material technique; accreditation and certification in the Single European Market; development of equipment in welding and cutting techniques; quality assurance in welding technique; welding additives and welding aid materials; work and health protection in welding technique; training and qualification of personnel; basis of welding technique in Europe - test technique. (MM)

  8. Investigation of Effect of Welding Current on Welding Penetration in Covered Electrode Arc Welding And MIG Welding

    OpenAIRE

    Bekir ÇEVİK

    2013-01-01

    In this study, the effect of welding current on penetration in covered electrode arc welding and MIG (Metal Inert Gas) welding was investigated. St 37 quality steel materials were used in the experiments. Three different welding current (60, 90 and 120 A with covered electrode arc welding, 100, 125 and 155 A with MIG welding) was selected for welding process and was made 200 mm long weld. The welded specimens were cut particular lengths, then metallographic tests were performed. As a result o...

  9. Laser tissue welding: a urological surgeon's perspective.

    Science.gov (United States)

    Poppas, D P; Scherr, D S

    1998-07-01

    Laser tissue welding has proven its efficacy in the laboratory setting when compared with more traditional modalities of tissue reapproximation. In the clinical environment, several areas including urethral reconstructive surgery have shown great promise. Several technological advancements including solder development, chromophore enhancement and temperature control have improved upon the welding process and have added more precision and reproducibility to the technique. The current potential applications for laser welding in urology are numerous. On a molecular level, growth factor supplementation has certain potential in improving upon weld site healing and wound strength. Laparoscopic surgery with its need for less cumbersome modes of tissue closure is a field that will greatly benefit from the technology of laser tissue welding. Surgical specialties outside of urology are also participating in developing the field of laser welding. In particular, cardiothoracic surgery, otolaryngology, plastic surgery, neurosurgery among others, have utilized the concept of laser tissue welding. There are many ares that have potential use for laser welding that have yet to be explored. Further investigation will likely reveal more applications for this valuable technology. PMID:9873775

  10. Introduction to Welding.

    Science.gov (United States)

    Fortney, Clarence; Gregory, Mike

    This curriculum guide provides six units of instruction on basic welding. Addressed in the individual units of instruction are the following topics: employment opportunities for welders, welding safety and first aid, welding tools and equipment, basic metals and metallurgy, basic math and measuring, and procedures for applying for a welding job.…

  11. Distortion Control during Welding

    NARCIS (Netherlands)

    Akbari Pazooki, A.M.

    2014-01-01

    The local material expansion and contraction involved in welding result in permanent deformations or instability i.e., welding distortion. Considerable efforts have been made in controlling welding distortion prior to, during or after welding. Thermal Tensioning (TT) describes a group of in-situ met

  12. Modelling of damage development and ductile failure in welded joints

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

    This thesis focuses on numerical analysis of damage development and ductile failure in welded joints. Two types of welds are investigated here. First, a study of the localization of plastic flow and failure in aluminum sheets, welded by the relatively new Friction Stir (FS) Welding method, has been......, a study of the damage development in Resistance SpotWelded joints, when subject to the commonly used static shear-lab or cross-tension testing techniques, has been carried out ([P3]-[P6]). The focus in thesis is on the Advanced High Strength Steels, Dual-Phase 600, which is used in for example, the...... conducted ([P1], [P2], [P7]-[P9]). The focus in the thesis is on FS-welded 2xxx and 6xxx series of aluminum alloys, which are attractive, for example, to the aerospace industry, since the 2024 aluminum in particular, is typically classified as un-weldable by conventional fusion welding techniques. Secondly...

  13. Laser welding in space

    Science.gov (United States)

    Kaukler, W. F.; Workman, G. L.

    1991-01-01

    Autogenous welds in 304 stainless steel were performed by Nd-YAG laser heating in a simulated space environment. Simulation consists of welding on the NASA KC-135 aircraft to produce the microgravity and by containing the specimen in a vacuum chamber. Experimental results show that the microgravity welds are stronger, harder in the fusion zone, have deeper penetration and have a rougher surface rippling of the weld pool than one-g welds. To perform laser welding in space, a solar-pumped laser concept that significantly increases the laser conversion efficiency and makes welding viable despite the limited power availability of spacecraft is proposed.

  14. Friction Stir Spot Welding of Polymer Materials

    OpenAIRE

    Bekir ÇEVİK

    2014-01-01

    Polymer materials are engineering materials used for various industrial fields. Polymer processing and fabrication techniques have developed with the advancement of technology. Friction Stir Spot Welding (FSSW) is a solid-state process in joining thermoplastic materials. In the present work, the polymeric material (Polyethylene) has been made to join by FSSW process. 3 mm thickness polyethylene materials were used in the experiments. Welding process was carried out by rotating 460 and 900 rpm...

  15. Development of TIG welding technique for endcap welding of PHWR MOX fuel elements

    International Nuclear Information System (INIS)

    Full text: Fabrication of PHWR fuel elements involves manufacture of fuel pellets, loading them in the zircaloy-4 clad tube and endcap welding of filled zircaloy-4 clad tube by resistance welding technique. This welding technique gives higher production rate but the welds are not amenable to non destructive techniques like radiography. The quality of the weld is assured by the destructive metallographic technique which is statistical in nature. DAE has recently decided to go ahead with plutonium recycling in PHWR in order to increase the burnup to around 10,000 MWD/Te to reduce the fuel cycle cost and reduce the requirement of uranium. The bundle design remains the same as it is being used in 235 MWe PHWR's in India. In the proposed nineteen element, fuel bundle the internal seven elements will contain MOX fuel pellets and external twelve elements will contain standard natural uranium dioxide pellets. MOX fuel elements will be fabricated at Advanced Fuel Fabrication Facility, BARC, Tarapur. It is proposed to make the fuel element by TIG welding technique which has the advantage of using radiography for the evaluation of the end plug weld. Further there will be no machining required over the weld bead which is a must for a resistance weld. However, the use of TIG technique requires change in endcap design and use of these endcaps leads to marginal (<1 %) decrease in stack length to maintain the same fuel element length as used in natural uranium dioxide PHWR, fuel bundle. This paper describes the development work carried out at AFFF on TIG welding of endplugs for PHWR fuel elements with the new plug design, optimisation of welding parameters and the results of the welding trials

  16. Orbital welding technique

    International Nuclear Information System (INIS)

    The TIG (Tungsten-inert gas) orbital welding technique is applied in all areas of pipe welding. The process is mainly used for austenitic and ferritic materials but also for materials like aluminium, nickel, and titanium alloys are commonly welded according to this technique. Thin-walled as well as thick-walled pipes are welded economically. The application of orbital welding is of particular interest in the area of maintenance of thick-walled pipes that is described in this article. (orig.)

  17. Revolutionary optical sensor for physiological monitoring in the battlefield

    Science.gov (United States)

    Kingsley, Stuart A.; Sriram, Sriram; Pollick, Andrea; Marsh, John

    2004-09-01

    SRICO has developed a revolutionary approach to physiological status monitoring using state-of-the-art optical chip technology. The company"s patent pending Photrode is a photonic electrode that uses unique optical voltage sensing technology to measure and monitor electrophysiological parameters. The optical-based monitoring system enables dry-contact measurements of EEG and ECG signals that require no surface preparation or conductive gel and non-contact measurements of ECG signals through the clothing. The Photrode applies high performance optical integrated circuit technology, that has been successfully implemented in military & commercial aerospace, missile, and communications applications for sensing and signal transmission. SRICO"s award winning Photrode represents a new paradigm for the measurement of biopotentials in a reliable, convenient, and non-intrusive manner. Photrode technology has significant applications on the battlefield for rapid triage to determine the brain dead from those with viable brain function. An ECG may be obtained over the clothing without any direct skin contact. Such applications would enable the combat medic to receive timely medical information and to make important decisions regarding identification, location, triage priority and treatment of casualties. Other applications for the Photrode include anesthesia awareness monitoring, sleep medicine, mobile medical monitoring for space flight, emergency patient care, functional magnetic resonance imaging, various biopotential signal acquisition (EMG, EOG), and routine neuro and cardio diagnostics.

  18. Rifaximin: The Revolutionary Antibiotic Approach for Irritable Bowel Syndrome.

    Science.gov (United States)

    Triantafyllou, Konstantinos; Sioulas, Athanasios D; Giamarellos-Bourboulis, Evangelos J

    2015-01-01

    A large number of clinical studies using breath testing and a smaller number of studies using quantitative cultures of the upper small intestine established a link between irritable bowel syndrome (IBS) and small intestinal bacterial overgrowth (SIBO). A series of 12 studies both prospective and retrospective in design in a population of patients with SIBO without IBS showed that the non-absorbable antibiotic rifaximin can eradicate SIBO as proved through decrease of the exhaled hydrogen and methane in breath tests. The efficacy of rifaximin was superior over the comparator treatment in most of these studies. Based on these findings, short course rifaximin was tested in various concentrations in eight open-label trials in patients with IBS and proven SIBO by breath test. Similar efficacy of rifaximin was shown in SIBO eradication; this was accompanied by improvement of the global score for IBS symptoms. Finally, five double-blind randomized clinical trials were conducted in patients with IBS; four were placebo-controlled. The larger trials were TARGET 1 and TARGET 2 studies testing rifaximin at a regimen of 550 mg tid for 14 days. All trials showed a significant superiority of rifaximin over comparator for the improvement of global symptoms of IBS and bloating. Although the aforementioned results render rifaximin a revolutionary therapeutic approach for IBS, several concerns on induction of antimicrobial resistant flora remain. PMID:26202193

  19. CFD Vision 2030 Study: A Path to Revolutionary Computational Aerosciences

    Science.gov (United States)

    Slotnick, Jeffrey; Khodadoust, Abdollah; Alonso, Juan; Darmofal, David; Gropp, William; Lurie, Elizabeth; Mavriplis, Dimitri

    2014-01-01

    This report documents the results of a study to address the long range, strategic planning required by NASA's Revolutionary Computational Aerosciences (RCA) program in the area of computational fluid dynamics (CFD), including future software and hardware requirements for High Performance Computing (HPC). Specifically, the "Vision 2030" CFD study is to provide a knowledge-based forecast of the future computational capabilities required for turbulent, transitional, and reacting flow simulations across a broad Mach number regime, and to lay the foundation for the development of a future framework and/or environment where physics-based, accurate predictions of complex turbulent flows, including flow separation, can be accomplished routinely and efficiently in cooperation with other physics-based simulations to enable multi-physics analysis and design. Specific technical requirements from the aerospace industrial and scientific communities were obtained to determine critical capability gaps, anticipated technical challenges, and impediments to achieving the target CFD capability in 2030. A preliminary development plan and roadmap were created to help focus investments in technology development to help achieve the CFD vision in 2030.

  20. Electron beam, laser beam and plasma arc welding studies

    Science.gov (United States)

    Banas, C. M.

    1974-01-01

    This program was undertaken as an initial step in establishing an evaluation framework which would permit a priori selection of advanced welding processes for specific applications. To this end, a direct comparison of laser beam, electron beam and arc welding of Ti-6Al-4V alloy was undertaken. Ti-6Al-4V was selected for use in view of its established welding characteristics and its importance in aerospace applications.

  1. Residual stresses in zircaloy welds

    International Nuclear Information System (INIS)

    Welds in Zirconium-based alloys are susceptible to hydrogen embrittlement, as H enters the material due to dissociation of water. The yield strain for hydride cracking has a complex dependence on H concentration, stress state and texture. The large thermal gradients produced by the applied heat; drastically changes the texture of the material in the heat affected zone, enhancing the susceptibility to delayed hydride cracking. Normally hydrides tend to form as platelets that are parallel to the normal direction, but when welding plates, hydride platelets may form on cooling with their planes parallel to the weld and through the thickness of the plates. If, in addition to this there are significant tensile stresses, the susceptibility of the heat affected zone to delayed hydride cracking will be increased. Here we have measured the macroscopic and microscopic residual stressed that appear after PLASMA welding of two 6mm thick Zircaloy-4 plates. The measurements were based on neutron and synchrotron diffraction experiments performed at the Isis Facility, UK, and at Advanced Photon Source, USA, respectively. The experiments allowed assessing the effect of a post-weld heat treatment consisting of a steady increase in temperature from room temperature to 450oC over a period of 4.5 hours; followed by cooling with an equivalent cooling rate. Peak tensile stresses of (175± 10) MPa along the longitudinal direction were found in the as-welded specimen, which were moderately reduced to (150±10) MPa after the heat-treatment. The parent material showed intergranular stresses of (56±4) MPa, which disappeared on entering the heat-affected zone. In-situ experiments during themal cyclong of the material showed that these intergranular stresses result from the anisotropy of the thermal expansion coefficient of the hexagonal crystal lattice.

  2. Diffusion welding

    International Nuclear Information System (INIS)

    After a brief recall of the principle, and of the advantages of the method, we give some examples of metallic bonding in a first part where we describe preliminary trials: Ta-Mo, Zr-Zr, Zr-Nb, Nb-stainless steel, Mo-stainless steel, aluminium-aluminium (A5-A5). The second part of the note is devoted to trials on construction elements: on tubular elements for bonding between Mo or Nb on one hand, and stainless steel on the other hand (We indicate in what conditions the bonding are tight and what are their mechanical strength and their resistance to thermic cycles). We indicate, in this chapter, a method to obtain radiation windows in Be welded on an element made of stainless steel. (authors)

  3. Understanding metal vaporizaiton from laser welding.

    Energy Technology Data Exchange (ETDEWEB)

    DebRoy, Tarasankar (The Pennsylvania State University, University Park, PA); Fuerschbach, Phillip William; He, Xiuli (The Pennsylvania State University, University Park, PA); Norris, Jerome T.

    2003-09-01

    The production of metal vapor as a consequence of high intensity laser irradiation is a serious concern in laser welding. Despite the widespread use of lasers in manufacturing, little fundamental understanding of laser/material interaction in the weld pool exists. Laser welding experiments on 304 stainless steel have been completed which have advanced our fundamental understanding of the magnitude and the parameter dependence of metal vaporization in laser spot welding. Calculations using a three-dimensional, transient, numerical model were used to compare with the experimental results. Convection played a very important role in the heat transfer especially towards the end of the laser pulse. The peak temperatures and velocities increased significantly with the laser power density. The liquid flow is mainly driven by the surface tension and to a much less extent, by the buoyancy force. Heat transfer by conduction is important when the liquid velocity is small at the beginning of the pulse and during weld pool solidification. The effective temperature determined from the vapor composition was found to be close to the numerically computed peak temperature at the weld pool surface. At very high power densities, the computed temperatures at the weld pool surface were found to be higher than the boiling point of 304 stainless steel. As a result, vaporization of alloying elements resulted from both total pressure and concentration gradients. The calculations showed that the vaporization was concentrated in a small region under the laser beam where the temperature was very high.

  4. A martyr for modernity: Qiu Jin -- feminist warrior, and revolutionary.

    Science.gov (United States)

    Fan, H; Mangan, J A

    2001-01-01

    Qui Jin, at one level, was an oriental twentieth-century Judith, the mythical Jewish widow from Bethulia who cut off the head of Holofernes, the Assyrian general besieging the city, thus saving the Israelites from destruction. Qui Jin was, as Judith was, a self-reliant heroine who when others seemed 'helpless and demoralized undertook to save them single-handedly', or in her case virtually single-handedly. This, of course, was both her making and her unmaking. In Chinese terms the story of Qui Jin, like the story of Judith if less famous, less publicised, more recent, is the story of an icon at once central and at the same time marginal to tradition. She contradicted the most cherished customs on Confucian Chinese culture. She was a radical force who thrust her way to the centre of the concentric circles of customs surrounding this culture and was pushed back to the margins by conservatism. Nevertheless Qui Jin was not without success. She challenged a long-established mythology of exclusively masterful patriarchy - and created a counter myth of purposeful patriotic feminism. She was a counter-cultural icon who changed perceptions of Chinese femininity. She gave courage, confidence and purpose to those women who came after her and absorbed her ambitions for modern Chinese womanhood. For them she was a modern national heroine and a personification of a modern nation of equal men and women. For Qui Jin the body was an instrument of female revolution to be trained, strengthened and prepared for confrontation. As a revolutionary militant she was a failure; as a revolutionary talisman she was a success. For the Chinese women of the 1911 Revolution hers was an exemplary emancipatory story: subscribe, struggle, sacrifice. Patriotism through feminism is the purpose. Her heroism was firmly outside the historic patriarchal order. Her adulation is thus all the more remarkable because of the profound traditions she rejected, the controversial mannerisms she adopted, the

  5. Colosed-Loop Control of the Thermal Stir Welding Process to Enable Rapid Process/Ppart Qualification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Thermal Stir Welding (TSW) provides advancement over the more conventional Friction Stir Welding (C-FSW) process because it separates the primary processes...

  6. Closed-Loop Control of the Thermal Stir Welding Process to Enable Rapid Process/Part Qualification Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Thermal Stir Welding (TSW) provides advancement over the more conventional Friction Stir Welding (C-FSW) process because it separates the primary processes...

  7. Suburban Narratives Revisited: Problematics of Gender and the American Family in Richard Yates' Revolutionary Road

    OpenAIRE

    2012-01-01

    The thesis examines the postwar author Richard Yates and his novel Revolutionary Road in relation to gender roles, suburbia and the American family. My aim is for Richard Yates to be acknowledged as an author who can offer great insights into both the political, socio- historical and literary landscape of the 1950s, and particularly the struggles of restrictive gender roles within a suburban context. The first chapter revolves around gender roles and masculinity issues in Revolutionary...

  8. Revolutionary Art – Nationalism – Anti-Semitism: The Case of Wagner

    OpenAIRE

    Goran Gretić

    2015-01-01

    The article deals with the political aspects of revolutionary art of Richard Wagner. Through reading of Wagner’s artistic-philosophical project by his most influential interpreters – Friedrich Nietzsche, Thomas Mann and Theodor Adorno – author offers intellectual history of the reception of this project. Discourse on Wagner’s revolutionary art leads to the assessment of the influence Wagner’s cultural anti-Semitism and nationalism had on European politics in 20th century.

  9. Revolutionary Art – Nationalism – Anti-Semitism: The Case of Wagner

    Directory of Open Access Journals (Sweden)

    Goran Gretić

    2015-05-01

    Full Text Available The article deals with the political aspects of revolutionary art of Richard Wagner. Through reading of Wagner’s artistic-philosophical project by his most influential interpreters – Friedrich Nietzsche, Thomas Mann and Theodor Adorno – author offers intellectual history of the reception of this project. Discourse on Wagner’s revolutionary art leads to the assessment of the influence Wagner’s cultural anti-Semitism and nationalism had on European politics in 20th century.

  10. Laser Seam welding method

    International Nuclear Information System (INIS)

    The present invention provides a laser seam welding method for welding spacers to be used in nuclear fuel assemblies at a stable quality. Namely, the laser seam welding method comprises irradiating, while moving, laser beams to a portion to be welded. In this case, data of the shapes and characteristics of the portion to be welded are inputted to restrict the range of the welding of the portion to be welded. The power, moving speed, distance to a focal point and energy of the laser beams are controlled in the midway of the range for the welding. Then, a welding nugget having a shape defined to a portion to be welded can be formed thereby enabling to keep the portion to be welded to stable quality. As a result, failed welding can be eliminated, and strength of joint can be guaranteed. In addition, auxiliary products of portions to be welded, for example, springs are not failed by laser beams. As a result, satisfactory spacers can be provided. (I.S.)

  11. Microstructures in laser welded high strength steels

    Science.gov (United States)

    Rizzi, P.; Bellingeri, S.; Massimino, F.; Baldissin, D.; Battezzati, L.

    2009-01-01

    In this work, the effect of laser welding on the microstructure was studied for three Advanced High Strength Steels: transformation induced plasticity steel (TRIP), dual phase steel (DP) and martensitic steel. Two sheets of the same steel were laser welded and a microstructural study was performed by optical microscopy, scanning electron microscopy and X-ray diffraction. For all samples the welded zone was constituted by martensite and the heat affected zone shows a continuous change in microstructure depending on temperatures reached and on the different cooling rates. The change in mechanical properties in the welded area was followed by Vickers micro-hardness measurements. Quasi binary phase diagrams were calculated and, according to position of T0 lines, it was deduced that austenite is the primary phase forming during rapid solidification for all steels.

  12. Microstructures in laser welded high strength steels

    International Nuclear Information System (INIS)

    In this work, the effect of laser welding on the microstructure was studied for three Advanced High Strength Steels: transformation induced plasticity steel (TRIP), dual phase steel (DP) and martensitic steel. Two sheets of the same steel were laser welded and a microstructural study was performed by optical microscopy, scanning electron microscopy and X-ray diffraction. For all samples the welded zone was constituted by martensite and the heat affected zone shows a continuous change in microstructure depending on temperatures reached and on the different cooling rates. The change in mechanical properties in the welded area was followed by Vickers micro-hardness measurements. Quasi binary phase diagrams were calculated and, according to position of T0 lines, it was deduced that austenite is the primary phase forming during rapid solidification for all steels.

  13. Handbook of Plastic Welding

    DEFF Research Database (Denmark)

    Islam, Aminul

    The purpose of this document is to summarize the information about the laser welding of plastic. Laser welding is a matured process nevertheless laser welding of micro dimensional plastic parts is still a big challenge. This report collects the latest information about the laser welding of plastic...... materials and provides an extensive knowhow on the industrial plastic welding process. The objectives of the report include: - Provide the general knowhow of laser welding for the beginners - Summarize the state-of-the-art information on the laser welding of plastics - Find the technological limits in terms...... of design, materials and process - Find the best technology, process and machines adaptive to Sonion’s components - Provide the skills to Sonion’s Design Engineers for successful design of the of the plastic components suitable for the laser welding The ultimate goal of this report is to serve as a...

  14. Position welding using disk laser-GMA hybrid welding

    OpenAIRE

    C.-H. Kim; H.-S. Lim; J.-K. Kim

    2008-01-01

    Purpose: Position welding technology was developed by using disk laser-GMA hybrid welding in this research.Design/methodology/approach: The effect of hybrid welding parameters such as the shielding gas composition and laser-arc interspacing distance were investigated for the bead-on-plate welding. The pipe girth welding was implemented and the adequate arc welding parameters were selected according to the welding position from a flat position to an overhead position.Findings: The optimized sh...

  15. Characteristics of Welding Fumes

    OpenAIRE

    Johansson, Gerd; Malmqvist, Klas; Bohgard, Mats; Akselsson, Roland

    1981-01-01

    The aerosols from 13 common electric arc welding processes have been characterized regarding total emission, particle size distribution, elemental composition and, when applicable, the oxidation state of chromium. The characterizations have been performed systematically for different combinations of welding current and welding voltage.

  16. Instructional Guidelines. Welding.

    Science.gov (United States)

    Fordyce, H. L.; Doshier, Dale

    Using the standards of the American Welding Society and the American Society of Mechanical Engineers, this welding instructional guidelines manual presents a course of study in accordance with the current practices in industry. Intended for use in welding programs now practiced within the Federal Prison System, the phases of the program are…

  17. Welding Course Curriculum.

    Science.gov (United States)

    Genits, Joseph C.

    This guide is intended for use in helping students gain a fundamental background on the major aspects of the welding trade. The course emphasis is on mastery of the manipulative skills necessary to develop successful welding techniques and on acquisition of an understanding of the specialized tools and equipment used in welding. The first part…

  18. Active weld control

    Science.gov (United States)

    Powell, Bradley W.; Burroughs, Ivan A.

    1994-01-01

    Through the two phases of this contract, sensors for welding applications and parameter extraction algorithms have been developed. These sensors form the foundation of a weld control system which can provide action weld control through the monitoring of the weld pool and keyhole in a VPPA welding process. Systems of this type offer the potential of quality enhancement and cost reduction (minimization of rework on faulty welds) for high-integrity welding applications. Sensors for preweld and postweld inspection, weld pool monitoring, keyhole/weld wire entry monitoring, and seam tracking were developed. Algorithms for signal extraction were also developed and analyzed to determine their application to an adaptive weld control system. The following sections discuss findings for each of the three sensors developed under this contract: (1) weld profiling sensor; (2) weld pool sensor; and (3) stereo seam tracker/keyhole imaging sensor. Hardened versions of these sensors were designed and built under this contract. A control system, described later, was developed on a multiprocessing/multitasking operating system for maximum power and flexibility. Documentation for sensor mechanical and electrical design is also included as appendices in this report.

  19. Butt welding characteristics of austenitic 304 stainless steel using a continuous wave Nd:YAG laser beam

    International Nuclear Information System (INIS)

    Laser beam welding is increasingly being used in welding of structural steels. The laser welding process is one of the most advanced manufacturing technologies owing to its high speed and deep penetration. The thermal cycles associated with laser welding are generally much faster than those involved in conventional arc welding processes, leading to a rather small weld zone. Experiments are performed for 304 stainless steel plates changing several process parameters such as laser power, welding speed, shielding gas flow rate, presence of surface pollution, with fixed or variable gap and misalignment between the similar and dissimilar plates, etc. The following conclusions can be drawn that laser power and welding speed have a pronounced effect on size and shape of the fusion zone. Increase in welding speed resulted in an increase in weld depth/ aspect ratio and hence a decease in the fusion zone size. The penetration depth increased with the increase in laser power

  20. Comparing Laser Welding Technologies with Friction Stir Welding for Production of Aluminum Tailor-Welded Blanks

    Energy Technology Data Exchange (ETDEWEB)

    Hovanski, Yuri; Carsley, John; Carlson, Blair; Hartfield-Wunsch, Susan; Pilli, Siva Prasad

    2014-01-15

    A comparison of welding techniques was performed to determine the most effective method for producing aluminum tailor-welded blanks for high volume automotive applications. Aluminum sheet was joined with an emphasis on post weld formability, surface quality and weld speed. Comparative results from several laser based welding techniques along with friction stir welding are presented. The results of this study demonstrate a quantitative comparison of weld methodologies in preparing tailor-welded aluminum stampings for high volume production in the automotive industry. Evaluation of nearly a dozen welding variations ultimately led to down selecting a single process based on post-weld quality and performance.

  1. Effect of Welding Speeds on Mechanical Properties of Level Compensation Friction Stir Welded 6061-T6 Aluminum Alloy

    Science.gov (United States)

    Wen, Quan; Yue, Yumei; Ji, Shude; Li, Zhengwei; Gao, Shuangsheng

    2016-04-01

    In order to eliminate the flash, arc corrugation and concave in weld zone, level compensation friction stir welding (LCFSW) was put forward and successfully applied to weld 6061-T6 aluminum alloy with varied welding speed at a constant tool rotational speed of 1,800 rpm in the present study. The glossy joint with equal thickness of base material can be attained, and the shoulder affected zone (SAZ) was obviously reduced. The results of transverse tensile test indicate that the tensile strength and elongation reach the maximum values of 248 MPa and 7.1% when the welding speed is 600 mm/min. The microhardness of weld nugget (WN) is lower than that of base material. The tensile fracture position locates at the heat affected zone (HAZ) of the advancing side (AS), where the microhardness is the minimum. The fracture surface morphology represents the typical ductile fracture.

  2. HAZ development and accelerated post-weld natural ageing in ultrasonic spot welding aluminium 6111-T4 automotive sheet

    International Nuclear Information System (INIS)

    By careful hardness measurements, supported by electron microscopy, it has been shown that there is a clearly observable heat-affected zone (HAZ) when ultrasonic spot welding (USW) aluminium automotive alloys like AA6111-T4, the severity of which depends on the welding energy. In contrast, it has been previously reported that because of the low-energy input with USW no HAZ can be detected. Immediately after welding, softening is seen in the weld zone relative to the normal T4 starting condition. However, this is rapidly recovered by natural ageing, which masks the presence of a HAZ, and the weld strength over long natural ageing times significantly exceeds that of the parent T4 material. This behaviour is caused by dissolution of the solute clusters and Guinier–Preston zones present in the T4 sheet due to the high weld temperatures, which were recorded to reach over 400 °C at the weld interface, followed by accelerated post-weld natural ageing. Interestingly, the weld zone was found to naturally age faster, and to a more advanced state, than the parent material. Modelling has been used to demonstrate that a large excess vacancy concentration can potentially be generated by the high-strain-rate dynamic deformation in USW, which can accelerate the natural ageing response seen in the weld.

  3. Thermal Stir Welding Development at Marshall Space Flight Center

    Science.gov (United States)

    Ding, Robert J.

    2008-01-01

    Solid state welding processes have become the focus of welding process development at NASA's Marshall Space Flight Center. Unlike fusion weld processes such as tungsten inert gas (TIG), variable polarity plasma arc (VPPA), electron beam (EB), etc., solid state welding processes do not melt the material during welding. The resultant microstructure can be characterized as a dynamically recrystallized morphology much different than the casted, dentritic structure typical of fusion weld processes. The primary benefits of solid state processes over fusion weld processes include superior mechanic properties and the elimination of thermal distortion and residual stresses. These solid state processes attributes have profoundly influenced the direction of advanced welding research and development within the NASA agency. Thermal Stir Welding (TSW) is a new solid state welding process being developed at the Marshall Space Flight Center. Unlike friction stir welding, the heating, stirring and forging elements of the weld process can be decoupled for independent control. An induction coil induces energy into a workpiece to attain a desired plastic temperature. An independently controlled stir rod, captured within non-rotating containment plates, then stirs the plasticized material followed by forging plates/rollers that work the stirred weld joint. The independent control (decoupling) of heating, stirring and forging allows, theoretically, for the precision control of microstructure morphology. The TSW process is being used to evaluate the solid state joining of Haynes 230 for ARES J-2X applications. It is also being developed for 500-in (12.5 mm) thick commercially pure grade 2 titanium for navy applications. Other interests include Inconel 718 and stainless steel. This presentation will provide metallurgical and mechanical property data for these high melting temperature alloys.

  4. Welding repair of a dissimilar weld and respective consequences for other German plants

    International Nuclear Information System (INIS)

    During a regular refueling outage in a German nuclear power plant in year 2000, additional non-destructive examinations have been performed on request of the Authority, to fulfill some recommendations of the independent experts with regard to the retrospective application of the Basic Safety Concept for the ferritic main coolant piping of this plant. During these inspections, indications were found in a dissimilar weld between one of the fifteen MCL (main coolant lines) nozzles and the ECC (emergency core cooling) system piping. By means of on-site metallography and laboratory investigations on three boat samples taken from this weld, it could be shown that the indications were due to hot cracking in the surface layer of the weld. In the course of these investigations, at three locations at the circumference of the weld, dis-bonding defects were found between the ferritic base metal of the nozzle and the austenitic weld butter, which has been applied to join the nozzle to the austenitic safe-end. According to the results of the extensive investigations, the dis-bonding occurred during the manufacturing process after stress-relief heat-treatment of the buttering during the welding of the austenitic safe-end to the butter material. There was no evidence for any crack growth during operation of the plant. Due to the large size of the boat-samples, a weld repair was mandatory. This repair has been performed using the so-called temper-bead technique as specified in the ASME Code, without subsequent stress relief heat treatment, using an advanced automatic orbital TIG welding process. The welding has been successfully performed without the need of further repair work. For those dissimilar welds, all other plants, except one, had used Inconel welding material for buttering the ferritic nozzle instead of stainless steel welding metal. For metallurgical reasons, dis-bonding along the fusion line for Inconel buttered dissimilar welds is unlikely to occur. Nevertheless all

  5. Hybrid Welding Possibilities of Thick Sections for Arctic Applications

    Science.gov (United States)

    Bunaziv, Ivan; Akselsen, Odd M.; Ren, Xiaobo; Salminen, Antti

    The arctic shelf contains about 20% of all undiscovered hydrocarbons on our planet, therefore oil and gas industry requires advanced steels to be used which withstand appropriate fracture toughness up to -60 °C and suitable welding technologies. High brightness laser with combination with arc source can be appropriate joining process even for very high strength advanced steels above 700 MPa for low temperature applications. Hybrid welding has improved each year becoming more standardized and reliable welding process. However, until now, its application was limited to shipbuilding and pipeline industry. Due to many reasonable advantages, hybrid welding, especially when it is combined with MIG/MAG, can be used in every possible industry. Inherent filler wire addition from the MIG/MAG source can improve fracture toughness at lower temperatures and increase overall productivity. This paper provides information about recent breakthrough in hybrid welding of thick section high-strength steels.

  6. Effect of formation and state of interface on joint strength in friction stir spot welding for advanced high strength steel sheets

    Science.gov (United States)

    Taniguchi, Koichi; Matsushita, Muneo; Ikeda, Rinsei; Oi, Kenji

    2014-08-01

    The tensile shear strength and cross tension strength of friction stir spot welded joints were evaluated in the cases of lap joints of 270 N/mm2 grade and 980 N/mm2 grade cold rolled steel sheets with respect to the stir zone area, hardness distribution, and interface condition between the sheets. The results suggested that both the tensile shear strength and cross tension strength were based on the stir zone area and its hardness in both grades of steel. The "hook" shape of the interface also affected the joint strength. However, the joining that occurred across the interfaces had a significant influence on the value of the joint strength in the case of the 270 N/mm2 grade steel.

  7. Effect of welding parameters of Gas Metal Arc welding on weld bead geometry: A Review

    Directory of Open Access Journals (Sweden)

    Pushp Kumar Baghel

    2012-07-01

    Full Text Available Weld quality comprises bead geometry and its microstructure, which influence the mechanical properties of the weld. This brief review illustrates the effect of pulse parameters on weld quality. The responsefactors, namely bead penetration, weld width, reinforcement height, weld penetration shape factor and weld reinforcement form factor as affected by arc voltage, wire feed rate, welding speed, gas flow rate and nozzle-toplate distance has also been analysed

  8. Welding method, and welding device for use therein, and method of analysis for evaluating welds

    OpenAIRE

    Aendenroomer, A.J.; Den Ouden, G.; Xiao, Y.H.; Brabander, W.A.J.

    1995-01-01

    Described is a method of automatically welding pipes, comprising welding with a pulsation welding current and monitoring, by means of a sensor, the variations occurring in the arc voltage caused by weld pool oscillations. The occurrence of voltage variations with only frequency components below 100 Hz indicates excessive welding through; the occurrence of voltage variations with only frequency components above 100 Hz indicates in sufficient welding through; a welding process showing proper we...

  9. Study on Sensor Design Technique for Real-Time Robotic Welding Tracking System

    International Nuclear Information System (INIS)

    Based on visual measurement techniques, the real-time robotic welding tracking system achieves real-time adjustment for robotic welding according to the position and shape changes of a workpiece. In system design, the sensor design technique is so important that its performance directly affects the precision and stability of the tracking system. Through initiative visual measurement technology, a camera unit for real-time sampling is built with multiple-strip structured light and a high-performance CMOS image sensor including 1.3 million pixels; to realize real-time data process and transmission, an image process unit is built with FPGA and DSP. Experiments show that the precision of this sensor reaches 0.3mm, and band rate comes up to 10Mbps, which effectively improves robot welding quality.With the development of advanced manufacturing technology, it becomes an inexorable trend to realize the automatic, flexible and intelligent welding product manufacture. With the advantage of interchangeability and reliability, robotic welding can boost productivity, improve work condition, stabilize and guarantee weld quality, and realize welding automation of the short run products [1]. At present, robotic welding has already become the application trend of automatic welding technology. Traditional welding robots are play-back ones, which cannot adapt environment and weld distortion. Especially in the more and more extensive arc-welding course, the deficiency and limitation of play-back welding technology becomes more prominent because of changeable welding condition. It becomes one of the key technology influencing the development of modern robotic welding technology to eliminate or decrease uncertain influence on quality of welding such as changing welding condition etc [2]. Based on visual measuring principle, this text adopts active visual measuring technology, cooperated with high-speed image process and transmission technology to structure a tracking sensor, to realize

  10. Nuclear pipework - welding and inspection

    International Nuclear Information System (INIS)

    The subject is covered in sections: introduction emphasizing need for perfection in welding nuclear pipework; detailed procedures (British Standards, TIG welding, automatic orbital TIG welding machines); unacceptable faults; improving performance (higher quality of commercially-available grades of stainless steels); auto welding; testing 'nuclear' welding; safe working (standard specifications, radiography); training; radiographic techniques; radiographic procedures; other inspections. (U.K.)

  11. Position welding using disk laser-GMA hybrid welding

    Directory of Open Access Journals (Sweden)

    C.-H. Kim

    2008-05-01

    Full Text Available Purpose: Position welding technology was developed by using disk laser-GMA hybrid welding in this research.Design/methodology/approach: The effect of hybrid welding parameters such as the shielding gas composition and laser-arc interspacing distance were investigated for the bead-on-plate welding. The pipe girth welding was implemented and the adequate arc welding parameters were selected according to the welding position from a flat position to an overhead position.Findings: The optimized shielding gas composition and laser-arc interspacing distance for disk laser-GMA hybrid welding were 80% Ar- 20% CO2 and 2mm, respectively for the bead-on-plate welding. The sound welds could be achieved even in the pipe girth welding, but the proper joint shape should be prepared.Research limitations/implications: The laser-arc hybrid welding was implemented for pipe girth welding as a kind of 3-dimensional laser welding and the process parameters could be optimized according to the various target materials and sizes.Practical implications: The optimized process parameters for the disk laser-arc hybrid welding can extend the application of the laser hybrid welding technology.Originality/value: This research showed the possibility of the disk laser-GMA hybrid welding as new pipe girth welding technique. The behaviour of molten pool and droplet transfer could enhance understanding of the hybrid welding.

  12. Welding characteristics of austenitic 304 stainless steel using a continuous wave Nd:YAG laser beam

    International Nuclear Information System (INIS)

    Laser beam welding is increasingly being used in welding of structural steels. The laser welding process is one of the most advanced manufacturing technologies owing to its high speed and deep penetration. The thermal cycles associated with laser welding are generally much faster than those involved in conventional welding processes, leading to a rather small weld zone. Experiments are performed for 304 stainless steel plates changing several process parameter such as laser power, welding speed, shielding gas flow rate, presence of surface pollution, with fixed or variable gap and misalignment between the similar and dissimilar and plates, etc. The follow conclusions can be drawn that laser power and welding speed have a pronounced effect on size and shape of the fusion zone

  13. Properties of weld deposit for butt weldings of reactor components

    International Nuclear Information System (INIS)

    Mechanical properties of weld deposit type MnNiMo from submerged arc- and manual shielded arc weldings for reactor components, influence of chemical composition and heat treatment condition, proposal for the testing of mechanical properties for weld deposit. (orig.)

  14. Applied Welding Technology. Technical Committee Report.

    Science.gov (United States)

    Idaho State Dept. of Education, Boise. Div. of Vocational Education.

    This Technical Committee Report prepared by industry representatives in Idaho lists the skills currently necessary for an employee in that state to obtain a job in applied welding technology, retain a job once hired, and advance in that occupational field. (Task lists are grouped according to duty areas generally used in industry settings, and are…

  15. The applicability of using low transformation temperature welding wire to minimize unwanted residual stresses and distortions

    International Nuclear Information System (INIS)

    Fusion welding of steel pressure vessels provides one of the most economic methods for creating such structures. However, the highly localised heat distribution, at the fused region gives rise to non-uniform heating/expansion and cooling/contraction of the weld and the surrounding base material, consequently giving rise to residual stresses and distortion. Several techniques are available to minimize welding distortions and residual stresses [1]. One feasible and efficient mitigation technique, that alters the inherent residual stresses developed during welding, includes the use of low transformation start temperature welding wire [2–4]. By altering the filler material and metallurgical transformations developed at the fusion zone and heat affected zone, wielded regions at the weld line can give rise to compressive residual stresses [2]. Consequently by establishing the appropriate chemical composition of the welding wire, a significant reduction in welding distortions can be achieved. This study focuses on establishing the merits of using different filler materials to minimize welding residual stresses and distortion through a thermal-metallurgical-elasto-plastic numerical parametric study. Numerical modelling of butt welded structures using three different filler materials is considered and the applicability of using low transformation temperature welding wire is investigated. The predicted residual stresses and distortions give a significant advance in understanding and control of welding distortion in welded fabrications. The chemical composition of the filler material and ultimately fused zone composition, leading to reductions in residual stresses and distortions is identified

  16. New welding technologies for car body frame welding

    OpenAIRE

    T. Węgrzyn; J. Piwnik; R. Burdzik; G. Wojnar; D. Hadryś

    2012-01-01

    Purpose: of that paper was analysing main welding process for car body welding. The main reason of it was investigate possibilities of getting varied amount of acicular ferrite (AF) in WMD (weld metal deposit). High amount of acicular ferrite influences positively impact toughness of weld. For optimal amount of AF it is necessary to have optimal chemical composition in WMD. Important role plays especially Ni. There were also tested new welding technology: welding with micro-jet cooling.Design...

  17. Development of temper bead welding by under water laser welding

    International Nuclear Information System (INIS)

    Toshiba has developed temper bead welding by under water laser welding as SCC counter measure for aged components in PWR and BWR nuclear power plants. Temper bead welding by under water laser welding technique recovers toughness of low alloy steel reactor vessel by employing proper the number of cladding layers and their welding conditions. In this report, some evaluation results of material characteristics of temper bead welded low alloy steel are presented. (author)

  18. Peculiarities of weld crystallization in the process of laser welding

    International Nuclear Information System (INIS)

    The effect of the process of laser welding of 08Kh18N10T steel on weld formation and crystallization is investigated. It is shown that at vsub(weld.) >= 40 m/h the lower sinked part of the weldpool stretched along the weld axis is crystallized quickly. Improvement in hot cracking resistance of weld metal in the process of laser welding results from the additional feeding with a liquid metal of the crystallizing part of the weldpool

  19. Missouri Agricultural Energy Saving Team-A Revolutionary Opportunity (MAESTRO)

    Energy Technology Data Exchange (ETDEWEB)

    McIntosh, Jane [MDA; Schumacher, Leon [University of Missouri

    2014-10-23

    The Missouri Agricultural Energy Saving Team-A Revolutionary Opportunity (MAESTRO) program brought together a team of representatives from government, academia, and private industry to enhance the availability of energy efficiency services for small livestock producers in the State of Missouri. The Missouri Department of Agriculture (MDA) managed the project via a subcontract with the University of Missouri (MU), College of Agriculture Food and Natural Resources, MU Extension, the MU College of Human Environmental Sciences, the MU College of Engineering, and the Missouri Agricultural and Small Business Development Authority (MASBDA). MU teamed with EnSave, Inc, a nationally-recognized expert in agricultural energy efficiency to assist with marketing, outreach, provision of farm energy audits and customer service. MU also teamed with independent home contractors to facilitate energy audits of the farm buildings and homes of these livestock producers. The goals of the project were to: (1) improve the environment by reducing fossil fuel emissions and reducing the total energy used on small animal farms; (2) stimulate the economy of local and regional communities by creating or retaining jobs; and (3) improve the profitability of Missouri livestock producers by reducing their energy expenditures. Historically, Missouri scientists/engineers conducted programs on energy use in agriculture, such as in equipment, grain handling and tillage practices. The MAESTRO program was the first to focus strictly on energy efficiency associated with livestock production systems in Missouri and to investigate the applicability and potential of addressing energy efficiency in animal production from a building efficiency perspective. A. Project Objectives The goal of the MAESTRO program was to strengthen the financial viability and environmental soundness of Missouri's small animal farms by helping them implement energy efficient technologies for the production facility, farm

  20. Microstructural Development during Welding of TRIP steels

    OpenAIRE

    Amirthalingam, M.

    2010-01-01

    The Advanced High Strength Steels (AHSS) are promising solutions for the production of lighter automobiles which reduce fuel consumption and increase passenger safety by improving crash-worthiness. Transformation Induced Plasticity Steel (TRIP) are part of the advanced high strength steels which offers a high strength and toughness combination with excellent uniform elongation. However, the higher alloying content of these steel limits their weldability and the thermal cycle of a welding proc...

  1. Challenges to Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

    This report originates from the compulsory defense during my Ph.D. study at the Technical University of Denmark. Resistance welding is an old and well-proven technology. Yet the emergence of more and more new materials, new designs, invention off new joining techniques, and more stringent...... requirement in quality have imposed challenges to the resistance welding. More some research and development have to be done to adapt the old technology to the manufacturing industry of the 21st century. In the 1st part of the report, the challenging factors to the resistance welding are reviewed. Numerical...... simulation of resistance welding has been under development for many years. Yet it is no easy to make simulation results reliable and accurate because of the complexity of resistance welding process. In the 2nd part of the report numerical modeling of resistance welding is reviewed, some critical factors to...

  2. Welding by laser beam

    International Nuclear Information System (INIS)

    A laser which does not require a vacuum and the beam from which can be projected over a distance without loss of power is sited outside a welding zone and the beam projected through a replaceable laser transparent window. The window is designed and shaped to facilitate access of the beam of workpiece items to be welded in containment. Either the workpiece or the laser beam may be moved during welding. (author)

  3. Underwater YAG laser welding technique

    International Nuclear Information System (INIS)

    When planning preventive maintenance of reactor components using welding, it is necessary to consider special environments such as narrow space or difficult accessibility while minimizing exposure to radiation in the reactor pressure vessel. Toshiba has developed an underwater neodymium: yttrium-aluminum-garnet (Nd: YAG) laser welding technique. The features of this welding technique are low-heat-input welding and compact welding machine dimensions for welding in narrow spaces. This paper provides a summary of the new welding technique as a reliable welding technology. (author)

  4. Dual wire welding torch and method

    Science.gov (United States)

    Diez, Fernando Martinez; Stump, Kevin S.; Ludewig, Howard W.; Kilty, Alan L.; Robinson, Matthew M.; Egland, Keith M.

    2009-04-28

    A welding torch includes a nozzle with a first welding wire guide configured to orient a first welding wire in a first welding wire orientation, and a second welding wire guide configured to orient a second welding wire in a second welding wire orientation that is non-coplanar and divergent with respect to the first welding wire orientation. A method of welding includes moving a welding torch with respect to a workpiece joint to be welded. During moving the welding torch, a first welding wire is fed through a first welding wire guide defining a first welding wire orientation and a second welding wire is fed through a second welding wire guide defining a second welding wire orientation that is divergent and non-coplanar with respect to the first welding wire orientation.

  5. Electron beam welding

    International Nuclear Information System (INIS)

    Electron-beam equipment is considered along with fixed and mobile electron-beam guns, questions of weld environment, medium and nonvacuum welding, weld-joint designs, tooling, the economics of electron-beam job shops, aspects of safety, quality assurance, and repair. The application of the process in the case of individual materials is discussed, giving attention to aluminum, beryllium, copper, niobium, magnesium, molybdenum, tantalum, titanium, metal alloys, superalloys, and various types of steel. Mechanical-property test results are examined along with the areas of application of electron-beam welding

  6. Electric arc welding gun

    Science.gov (United States)

    Luttrell, Edward; Turner, Paul W.

    1978-01-01

    This invention relates to improved apparatus for arc welding an interior joint formed by intersecting tubular members. As an example, the invention is well suited for applications where many similar small-diameter vertical lines are to be welded to a long horizontal header. The improved apparatus includes an arc welding gun having a specially designed welding head which is not only very compact but also produces welds that are essentially free from rolled-over solidified metal. The welding head consists of the upper end of the barrel and a reversely extending electrode holder, or tip, which defines an acute angle with the barrel. As used in the above-mentioned example, the gun is positioned to extend upwardly through the vertical member and the joint to be welded, with its welding head disposed within the horizontal header. Depending on the design of the welding head, the barrel then is either rotated or revolved about the axis of the vertical member to cause the electrode to track the joint.

  7. Manual tube welding torch

    International Nuclear Information System (INIS)

    In a welding torch which fits over a tube intermediate the ends thereof for welding the juncture between the tube and a boss on the back side of a tube plate, a split housing encloses a tungsten electrode, a filler wire duct and a fiber optic bundle arranged to observe the welding process. A shielding gas duct is provided in the housing. A screw is provided for setting electrode/work distance. Difficult remote tube welding operations can be performed with the apparatus. (author)

  8. Welding irradiated stainless steel

    International Nuclear Information System (INIS)

    Conventional welding processes produced severe underbead cracking in irradiated stainless steel containing 1 to 33 appm helium from n,a reactions. A shallow penetration overlay technique was successfully demonstrated for welding irradiated stainless steel. The technique was applied to irradiated 304 stainless steel that contained 10 appm helium. Surface cracking, present in conventional welds made on the same steel at the same and lower helium concentrations, was eliminated. Underbead cracking was minimal compared to conventional welding methods. However, cracking in the irradiated material was greater than in tritium charged and aged material at the same helium concentrations. The overlay technique provides a potential method for repair or modification of irradiated reactor materials

  9. Re: 3D Printing: A Revolutionary Advance for the Field of Urology?

    Directory of Open Access Journals (Sweden)

    Rebecca Neu

    2015-03-01

    Full Text Available 3D bioprinting based on thermal inkjet has great potential to develop promising approaches in tissue engineering and regenerative medicine for organ replacement. With layer by layer assembly, 3D tissues with complex structures can be printed using scanned CT or MRI images. The traditional tissueengineering approach of seeding the isolated cells to the pre-formed solid and rigid scaffolds was introduced in 1993 by Langer and Vacanti. With the thermal inkjet printers, the viability of printed mammalian cells at the different cell concentrations were varying from 85-95%. Bioprinting is flexible in that it can accommodate abroad variety of materials including organ-specific cells, blood vessels, smooth muscle and endothelial cells. With the 3D bioprinters, vascular or nevre systems can be enabled simultaneously during the organ construction with digital control. The research field of tissueengineering has seen explosive growth over the past five years where testing is stil primarily limited to animal specimens. In the literature, A. Atala and et al. demostared the power of 3D printing in thefield of urology. Especially, at the endstage of renal disease and bladder dysfunctions, tissue enginnering will be hopeful for the part of alternative treatment modality in nearfuture.

  10. Sensor for automatic welding; Sensor ga yosetsu jidoka wo kirihiraku

    Energy Technology Data Exchange (ETDEWEB)

    Sugitani, Y. [NKK Corp., Tokyo (Japan)

    1998-05-01

    This paper explains sensors in welding automating systems, and introduces examples of sensor technologies. Roles of sensors in the automating systems include stabilization of welding phenomena, in-process control of welding processes, remote surveillance for quality assurance, complementing of robot teaching operation, and remote surveillance for operating conditions to control production. Types of sensors that are used most frequently are arc sensors, electrode contact sensors, and probe contact sensors, followed by photo-sensors and electromagnetic sensors. The arc sensor uses welding arc itself as a sensor, being incorporated in most of arc welding robots. A laser sensor irradiates laser light onto an object, and detects reflected light by using a light receiving element to recognize position and shape of the object. For vision sensors, a technology is advancing, which utilizes a CCD camera to detect root gap, molten pond shapes, electrode tip shapes, and arc shapes. 5 refs., 13 figs.

  11. Imagining the Impossible: Revolutionary Critical Pedagogy against the 21st Century American Imperium

    Science.gov (United States)

    Scatamburlo-D'Annibale, Valerie

    2006-01-01

    This article examines some of the major Marxist-humanist themes that animate the revolutionary critical pedagogy delineated by Peter McLaren in recent years. Among these themes are radical universalism, an interrogation of the capitalization and commodification of human labor, and the interrelatedness of American imperialism and neoliberal…

  12. Revolutionary Peacemaking: Using a Critical Pedagogy Approach for Peacemaking with "Terrorists"

    Science.gov (United States)

    Best, Steven; McLaren, Peter; Nocella, Anthony J., II

    2007-01-01

    In this article, the authors note that peacemaking is based on working and dialoguing with radicals and militants, a point which many academics, government, and law enforcement agencies so easily forget. They aim to show that revolutionaries often have legitimate goals, needs, and demands which, if not addressed and respected, can prompt them to…

  13. Critical Revolutionary Pedagogy Is Made by Walking: In a World Where Many Worlds Coexist

    Science.gov (United States)

    McLaren, Peter; Jandric, Petar

    2014-01-01

    This conversation is the first systemic attempt to capture Peter McLaren's ideas about the relationships between critical revolutionary pedagogy and virtuality. It introduces the main problems with educational postmodernism, explains Peter's return towards the Marxist-humanist trajectory, and addresses contemporary challenges to…

  14. latin American literary testimony: historical foreshadowing of gender in the revolutionary discourse of the sixties

    Directory of Open Access Journals (Sweden)

    Victoria García

    2015-06-01

    Full Text Available The foundation of testimonio in Latin American literary field, initiated at the end of the ‘60, makes part of the institutionalization of the Cuban revolution, process where its projection to the rest of Latin America constitued a central problem. This paper studies political preconditions of testimonio. In particular, it analizes certain aspects of Cuban revolutionary discourse that anticipate features eventually developed by the literary genre, in the ways the relation between literature and politics is represented, and in the subjects of discourse that are proposed as embodiments of such relation. The paper introduces the question of Cuban revolution, as regards the exemplary status it acquired in Latin America during the sixties. Then, it examines the literary positioning represented by testimonio, as the corollary of a reflexive reconsideration operated by some Latin American writers and critics, concerning their historical role. Finally, it considers three representative documents of Cuban revolution and its continental projection: History will absolve me, by Fidel Castro, and Reminiscences of the Cuban revolutionary war and Bolivian diary, by Ernesto Guevara. We show the textual configuration of a revolutionary subject whose legitimity emerges not only from a political experience which testimony enunciates, but also from particular ways of living and representing literature in the context of a revolutionary practice. In the end of the sixties, the continental literary field would reaffirm such features as its discourse legitimating criteria, during the institutionalization of testimonio as its privileged genre.

  15. Revolutionary and Christian Ecumenes and Desire for Modernity in the Vietnamese Highlands

    DEFF Research Database (Denmark)

    Salemink, Oscar

    2015-01-01

    scholarship but in such phrases as ‘remote and backward areas’. For postcolonial Vietnam, I show that Highlanders were often motivated by the desire to become modern, and enacted such desires by joining ecumenes that embody modern universals, in particular revolutionary and Christian ecumenes, exemplifying...

  16. Revolutionary America, 1763-1789: A Bibliography. Volume 1 [and] Volume 2.

    Science.gov (United States)

    Gephart, Ronald M., Comp.

    The latest in a series of publications celebrating the bicentennial of American independence, this annotated bibliography lists the Library of Congress holdings concerning America during the Revolutionary War. Listed are the Library's most important primary and secondary sources, including books, manuscripts, serials, maps, and atlases. There are…

  17. Why is revolutionary development possible in materials and only innovative transformation in production procedures and products?

    OpenAIRE

    2004-01-01

    Based on fractal analysis of the past and future of general technology, the prediction of future development of materials technology (material technology and production technology) will be possible. The development of material technology can be revolutionary on the subatomic level. The development of the existing production procedures and products can be only innovative.

  18. Welding machine and welding process for nuclear fuel assembly structures

    International Nuclear Information System (INIS)

    The welding device comprises a mounting jig which receives the guide tubes and the assembly supporting structures in the desired spatial orientation. It also comprises a welding head which can travel on rails along the length of the guide tubes and has at least a welding spring chuck movable in two axes and rotatable relative to the welding machine; the spring chuck can pass between two adjacent tube rows and takes a tubes where a weld is necessary. The welding spring chuck can apply spot-welding pulses. This is used for the assembly of guide tubes and bundles for water-cooled nuclear reactors

  19. Laser Welding in Space

    Science.gov (United States)

    Workman, Gary L.; Kaukler, William F.

    1989-01-01

    Solidification type welding process experiments in conditions of microgravity were performed. The role of convection in such phenomena was examined and convective effects in the small volumes obtained in the laser weld zone were observed. Heat transfer within the weld was affected by acceleration level as indicated by the resulting microstructure changes in low gravity. All experiments were performed such that both high and low gravity welds occurred along the same weld beam, allowing the effects of gravity alone to be examined. Results indicate that laser welding in a space environment is feasible and can be safely performed IVA or EVA. Development of the hardware to perform the experiment in a Hitchhiker-g platform is recomended as the next step. This experiment provides NASA with a capable technology for welding needs in space. The resources required to perform this experiment aboard a Shuttle Hitchhiker-pallet are assessed. Over the four year period 1991 to 1994, it is recommended that the task will require 13.6 manyears and $914,900. In addition to demonstrating the technology and ferreting out the problems encountered, it is suggested that NASA will also have a useful laser materials processing facility for working with both the scientific and the engineering aspects of materials processing in space. Several concepts are also included for long-term optimization of available solar power through solar pumping solid state lasers directly for welding power.

  20. Laser welding in space

    International Nuclear Information System (INIS)

    This paper reports on the design and construction, as well as typical results from performing low gravity laser welding experiments on NASA's KC-135 aircraft flying parabolic maneuvers to simulate low gravity. Results of the experiments are reported and some new concepts regarding the implementation of laser technology suitable for laser welding in space are presented

  1. Sorting Titanium Welding Rods

    Science.gov (United States)

    Ross, W. D., Jr.; Brown, R. L.

    1985-01-01

    Three types of titanium welding wires identified by their resistance to current flow. Welding-wire tester quickly identifies unknown titaniumalloy wire by touching wire with test probe, and comparing meter response with standard response. Before touching wire, tip of test probe dipped into an electrolyte.

  2. Welding Tubes In Place

    Science.gov (United States)

    Meredith, R.

    1984-01-01

    Special welding equipment joins metal tubes that carry pressurized cyrogenic fluids. Equipment small enough to be used in confined spaces in which such tubes often mounted. Welded joints lighter in weight and more leak-proof than joints made with mechanical fittings.

  3. Method for welding beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, R.D.; Smith, F.M.; O`Leary, R.F.

    1995-12-31

    A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon. Beryllium parts made using this method can be used as structural components in aircraft, satellites and space applications.

  4. Method for welding beryllium

    Energy Technology Data Exchange (ETDEWEB)

    Dixon, R.D.; Smith, F.M.; O`Leary, R.F.

    1997-04-01

    A method is provided for joining beryllium pieces which comprises: depositing aluminum alloy on at least one beryllium surface; contacting that beryllium surface with at least one other beryllium surface; and welding the aluminum alloy coated beryllium surfaces together. The aluminum alloy may be deposited on the beryllium using gas metal arc welding. The aluminum alloy coated beryllium surfaces may be subjected to elevated temperatures and pressures to reduce porosity before welding the pieces together. The aluminum alloy coated beryllium surfaces may be machined into a desired welding joint configuration before welding. The beryllium may be an alloy of beryllium or a beryllium compound. The aluminum alloy may comprise aluminum and silicon. 9 figs.

  5. Orbital welding technique; Orbitalschweisstechnik

    Energy Technology Data Exchange (ETDEWEB)

    Hoeschen, W. [Kraftanlagen Nukleartechnik GmbH, Heidelberg (Germany)

    2003-07-01

    The TIG (Tungsten-inert gas) orbital welding technique is applied in all areas of pipe welding. The process is mainly used for austenitic and ferritic materials but also for materials like aluminium, nickel, and titanium alloys are commonly welded according to this technique. Thin-walled as well as thick-walled pipes are welded economically. The application of orbital welding is of particular interest in the area of maintenance of thick-walled pipes that is described in this article. (orig.) [German] Die praktische Anwendung des Wolfram-Inertgas-(WIG-)Orbitalschweissverfahrens erfolgt in allen Sparten des Rohrleitungsbaues. Vorwiegend wird das Verfahren an austenitischen und ferritischen Werkstoffen eingesetzt. Aber auch andere Werkstoffe, wie Aluminium, Nickel- und Titanlegierungen, sind gaengige Praxis. Dabei werden sowohl duenn- als auch dickwandige Rohre wirtschaftlich verschweisst. In der Instandhaltung ist die Anwendung der Orbitaltechnik fuer dickwandige Rohre von besonderem Interesse und wird hier beschrieben. (orig.)

  6. Vacuum welding of metals

    International Nuclear Information System (INIS)

    This new welding process has been developed by the Commissariat a l'Energie Atomique (CEA) in France. The edges of the work-pieces are melted by the impact of an electron beam produced by an electron gun. Welding is carried out in a vacuum of 10-4 to 10-8 mm of mercury. The welding machine consists, diagrammatically, of: a) a metal enclosure in which a vacuum is produced; b) a cathode for electron emission, a high-voltage generator for accelerating these electrons, a focusing device; c) a mechanical device for moving (rotating) the work-piece. Advantages of the process: 1) possible welding of highly oxidizable metals (e.g. zirconium); 2) fabrication of high-vacuum-sealed metal containers; 3) production of very deeply penetrated welds. Therefore, this new process is particularly advantageous for atomic power applications, the fabrication of electron tubes and, more generally, for all industries in which very special metals are used. (author)

  7. Argon Welding Inside A Workpiece

    Science.gov (United States)

    Morgan, Gene E.

    1988-01-01

    Canopies convert large hollow workpiece into inert-gas welding chamber. Large manifold serves welding chamber for attachment of liner parts in argon atmosphere. Every crevice, opening and passageway provided with argon-rich environment. Weld defects and oxidation dramatically reduced; also welding time reduced.

  8. Friction Stir Welding of ODS and RAFM Steels

    Science.gov (United States)

    Yu, Zhenzhen; Feng, Zhili; Hoelzer, David; Tan, Lizhen; Sokolov, Mikhail A.

    2015-09-01

    Advanced structural materials such as oxide dispersion strengthened steels and reduced-activation ferritic/martensitic steels are desired in fusion reactors as primary candidate materials for first wall and blanket structures, due to their excellent radiation and high-temperature creep resistance. However, their poor fusion weldability has been the major technical challenge limiting practical applications. For this reason, solid-state friction stir welding (FSW) has been considered for such applications. In this work, the effect of FSW parameters on joining similar and dissimilar advanced structural steels was investigated. Scanning electron microscopy and electron backscatter diffraction methods were used to reveal the effects of FSW on grain size, micro-texture distribution, and phase stability. Hardness mapping was performed to evaluate mechanical properties. Post weld heat treatment was also performed to tailor the microstructure in the welds in order to match the weld zone mechanical properties to the base material.

  9. Robotic and automatic welding development at the Marshall Space Flight Center

    Science.gov (United States)

    Jones, C. S.; Jackson, M. E.; Flanigan, L. A.

    1988-01-01

    Welding automation is the key to two major development programs to improve quality and reduce the cost of manufacturing space hardware currently undertaken by the Materials and Processes Laboratory of the NASA Marshall Space Flight Center. Variable polarity plasma arc welding has demonstrated its effectiveness on class 1 aluminum welding in external tank production. More than three miles of welds were completed without an internal defect. Much of this success can be credited to automation developments which stabilize the process. Robotic manipulation technology is under development for automation of welds on the Space Shuttle's main engines utilizing pathfinder systems in development of tooling and sensors for the production applications. The overall approach to welding automation development undertaken is outlined. Advanced sensors and control systems methodologies are described that combine to make aerospace quality welds with a minimum of dependence on operator skill.

  10. Revolutionary Concepts for Helicopter Noise Reduction: SILENT Program

    Science.gov (United States)

    Edwards, Bryan; Cox, Charles; Booth, Earl R., Jr. (Technical Monitor)

    2002-01-01

    As part of a NASA initiative to reduce helicopter main rotor noise, a Phase 1 study has been performed of candidate noise reduction concepts. Both conventional and novel design technologies have been analyzed that reduce the community impact of helicopter operations. In this study the noise reduction potential and design implications are assessed for conventional means of noise reduction, e.g., tip speed reduction, tip shapes and airfoil tailoring, and for two innovative design concepts: modulated blade spacing and x-force control. Main rotor designs that incorporate modulated blade spacing are shown to have reduced peak noise levels in most flight operations. X-force control alters the helicopter's force balance whereby the miss distance between main rotor blades and shed vortices can be controlled. This control provides a high potential to mitigate BVI noise radiation. Each concept is evaluated using best practice design and analysis methods, achieving the study's aim to significantly reduce noise with minimal performance degradation and no vibration increase. It is concluded that a SILENT main rotor design, incorporating the modulated blade spacing concept, offers significantly reduced noise levels and the potential of a breakthrough in how a helicopter's sound is perceived and judged. The SILENT rotor represents a definite advancement in the state-of-the-art and is selected as the design concept for demonstration in Phase 2. A Phase 2 Implementation Plan is developed for whirl cage and wind tunnel evaluations of a scaled model SILENT rotor.

  11. RNAi technology: A Revolutionary tool for the colorectal cancer therapeutics

    Institute of Scientific and Technical Information of China (English)

    Wei Lv; Chao Zhang; Jia Hao

    2006-01-01

    With the many changes that have taken place in people's diet and lifestyle, colorectal cancer (CRC) has become a global concern. There were approximately 950000 new cases diagnosed and 500000 deaths recorded worldwide in 2000. It is the second most common type of cancer in the Western world, and it is the third most common type of digestive tumor in China. It is reported that the morbidity of CRC is 4.08/100000 for men and 3.30/100000 for women in China. Despite the rate of improvements in surgery, radiotherapy and chemotherapy, the overall five-year survival is around 50%. Therefore, novel treatment need to be developed in order to add to the therapeutic armamentarium.RNA interference (RNAi) is a sequence-specific posttranscriptional gene silencing mechanism, which is triggered by double-stranded RNA (dsRNA) and causes degradation of mRNA homologous in sequence to the dsRNA.This new approach has been successfully adopted to inhibit virus replication and tumorigenicity. Recent reports have described DNA vector-based strategies for delivery of small interfering RNA (siRNA) into mammalian cells, further expanding the utility of RNAi. With the development of the RNAi technology and deeper understanding of this field, a promising new modality of treatment appeared, which can be used in combination with the existing therapies .We reviewed the proceedings on the actualities and advancement of RNAi technology for colorectal cancer therapeutics.

  12. Welding development for V-Cr-Ti alloys

    Energy Technology Data Exchange (ETDEWEB)

    King, J.F.; Goodwin, G.M.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)

    1995-04-01

    A vanadium structure, cooled with helium, is a favored concept for an advanced breeding blanket for fusion systems. The objective of this task is to develop the metallurgical and technological base for the welding of thick sections of V-Cr-Ti. The subsize Charpy test results for electron beam weld metal from the V-5Cr-5Ti alloy has shown significant improvement in Charpy fracture energy compared to both gas tungsten arc weld metal and the base metal itself. These results are preliminary, however, and additional confirmation testing and analysis will be required to explain this improvement in properties.

  13. Advanced Algal Systems Fact Sheet

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-06-01

    Research and development (R&D) on advanced algal biofuels and bioproducts presents an opportunity to sustainably expand biomass resource potential in the United States. The Bioenergy Technologies Office’s (BETO’s) Advanced Algal Systems Program is carrying out a long-term, applied R&D strategy to lower the costs of algal biofuel production by working with partners to develop revolutionary technologies and conduct crosscutting analyses to better understand the potential

  14. Laser forming and welding processes

    CERN Document Server

    Yilbas, Bekir Sami; Shuja, Shahzada Zaman

    2013-01-01

    This book introduces model studies and experimental results associated with laser forming and welding such as laser induced bending, welding of sheet metals, and related practical applications. The book provides insight into the physical processes involved with laser forming and welding. The analytical study covers the formulation of laser induced bending while the model study demonstrates the simulation of bending and welding processes using the finite element method. Analytical and numerical solutions for laser forming and welding problems are provided.

  15. Elucidation of laser welding phenomena and factors affecting weld penetration and welding defects

    Science.gov (United States)

    Katayama, Seiji; Kawahito, Yousuke; Mizutani, Masami

    The behavior and effect of a plasma plume on the weld penetration are greatly different between CO2 laser welding and YAG, disk or fiber laser welding. The effects of the power and the power density on the weld penetration are elucidated. Spattering leading to the formation of underfilled weld beads is controlled by inclining the laser beam. Porosity is formed from bubbles generated from the tip of the keyhole at low welding speed or from the middle part of the keyhole at high laser power density. Cracking easily occurs in pulsed spot welding of aluminum alloys.

  16. Crisis Culture and the Waning of Revolutionary Politics

    Directory of Open Access Journals (Sweden)

    Steven Best

    2007-10-01

    Full Text Available Since the election of George Bush in 2000 (and his re-election in 2004, the tragedy of 9/11, the US invasion of Iraq in 2003, and ever more indicators of human-induced global climate change, the crisis in the social and natural worlds has sharpened considerably. The deterioration of society and nature demands a profound, systematic, and radical political response, yet in recent decades Left opposition movements have grown weaker in proportion to their importance. As the globe spirals ever deeper into disaster, with all things becoming ever more tightly knit into the tentacles of global capitalism, and as oppositional voices propose programs of reform and moderation at best, there is an urgent need for new conceptual and political maps and compasses to help steer humanity into a viable mode of existence. Karl Marx's 1843 call for a "ruthless criticism of everything existing" has never been more pressing and profound than in contemporary times of predatory global capitalism, neoliberalism, the World Trade Organization (WTO, the North American Free Trade Agreement (NAFTA, the demise of social democracies, the police states of George Bush and Tony Blair, the assault on liberties and the criminalization of dissent, species extinction, rainforest destruction, resource wars, and global warming.Given the advances of capitalism and the cooptation and retreat of radical politics, it is urgent that genuine oppositional viewpoints be kept alive and nurtured in intellectual, public, and political forums. When one considers the paucity of radical viewpoints that still survive, the project of Inclusive Democracy immediately comes to mind as one of the few, if not the only, coherent and comprehensive theoretical and political frameworks for systemic social change. Inclusive Democracy aims to develop a radical theoretical analysis of -- and political solution to -- the catastrophic social and environmental impact of the market economies spawned by Western

  17. Revolutionary systems for catalytic combustion and diesel catalytic particulate traps.

    Energy Technology Data Exchange (ETDEWEB)

    Stuecker, John Nicholas; Witze, Peter O.; Ferrizz, Robert Matthew; Cesarano, Joseph, III; Miller, James Edward

    2004-12-01

    This report is a summary of an LDRD project completed for the development of materials and structures conducive to advancing the state of the art for catalyst supports and diesel particulate traps. An ancillary development for bio-medical bone scaffolding was also realized. Traditionally, a low-pressure drop catalyst support, such as a ceramic honeycomb monolith, is used for catalytic reactions that require high flow rates of gases at high-temperatures. A drawback to the traditional honeycomb monoliths under these operating conditions is poor mass transfer to the catalyst surface in the straight-through channels. ''Robocasting'' is a unique process developed at Sandia National Laboratories that can be used to manufacture ceramic monoliths with alternative 3-dimensional geometries, providing tortuous pathways to increase mass transfer while maintaining low-pressure drops. These alternative 3-dimensional geometries may also provide a foundation for the development of self-regenerating supports capable of trapping and combusting soot particles from a diesel engine exhaust stream. This report describes the structures developed and characterizes the improved catalytic performance that can result. The results show that, relative to honeycomb monolith supports, considerable improvement in mass transfer efficiency is observed for robocast samples synthesized using an FCC-like geometry of alternating rods. Also, there is clearly a trade-off between enhanced mass transfer and increased pressure drop, which can be optimized depending on the particular demands of a given application. Practical applications include the combustion of natural gas for power generation, production of syngas, and hydrogen reforming reactions. The robocast lattice structures also show practicality for diesel particulate trapping. Preliminary results for trapping efficiency are reported as well as the development of electrically resistive lattices that can regenerate the structure

  18. Welding processes handbook

    CERN Document Server

    Weman, Klas

    2003-01-01

    Deals with the main commercially significant and commonly used welding processes. This title takes the student or novice welder through the individual steps involved in each process in an easily understood way. It covers many of the requirements referred to in European Standards including EN719, EN 729, EN 729 and EN 287.$bWelding processes handbook is a concise, explanatory guide to the main commercially significant and commonly-used welding processes. It takes the novice welder or student through the individual steps involved in each process in a clear and easily understood way. It is intended to provide an up-to-date reference to the major applications of welding as they are used in industry. The contents have been arranged so that it can be used as a textbook for European welding courses in accordance with guidelines from the European Welding Federation. Welding processes and equipment necessary for each process are described so that they can be applied to all instruction levels required by the EWF and th...

  19. Numerical simulation of material flow in AA6082 during friction stir spot welding

    OpenAIRE

    Gao, Zeng; Wang, Peng; CHENG, DONGFENG; Niu, Jitai; Sommitsch, Christof

    2015-01-01

    Friction stir spot welding (FSSW) is a new solid state joining technology based on the linear friction stir welding which can be used to replace the conventional resistance spot welding as well as riveting. However, some key problems such as heat transfer and thermoplastic material flow have not yet been studied sufficiently and block the application of this advanced technology. This paper presents the coupled thermo-mechanical viscoplastic finite element formulation based on the character of...

  20. A Review: Welding Of Dissimilar Metal Alloys by Laser Beam Welding & Friction Stir Welding Techniques

    OpenAIRE

    Ms. Deepika Harwani; Mr. Kapil Banker

    2014-01-01

    Welding of dissimilar metals has attracted attention of the researchers worldwide, owing to its many advantages and challenges. There is no denial in the fact that dissimilar welded joints offer more flexibility in the design and production of the commercial and industrial components. Many welding techniques have been analyzed to join dissimilar metal combinations. The objective of this paper is to review two such techniques – Laser welding and Friction stir welding. Laser beam we...

  1. Thermal stir welding process

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2012-01-01

    A welding method is provided for forming a weld joint between first and second elements of a workpiece. The method includes heating the first and second elements to form an interface of material in a plasticized or melted state interface between the elements. The interface material is then allowed to cool to a plasticized state if previously in a melted state. The interface material, while in the plasticized state, is then mixed, for example, using a grinding/extruding process, to remove any dendritic-type weld microstructures introduced into the interface material during the heating process.

  2. Thermal stir welding apparatus

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2011-01-01

    A welding method and apparatus are provided for forming a weld joint between first and second elements of a workpiece. The method includes heating the first and second elements to form an interface of material in a plasticized or melted state interface between the elements. The interface material is then allowed to cool to a plasticized state if previously in a melted state. The interface material, while in the plasticized state, is then mixed, for example, using a grinding/extruding process, to remove any dendritic-type weld microstructures introduced into the interface material during the heating process.

  3. Novel Optimization Methodology for Welding Process/Consumable Integration

    Energy Technology Data Exchange (ETDEWEB)

    Quintana, Marie A; DebRoy, Tarasankar; Vitek, John; Babu, Suresh

    2006-01-15

    Advanced materials are being developed to improve the energy efficiency of many industries of future including steel, mining, and chemical, as well as, US infrastructures including bridges, pipelines and buildings. Effective deployment of these materials is highly dependent upon the development of arc welding technology. Traditional welding technology development is slow and often involves expensive and time-consuming trial and error experimentation. The reason for this is the lack of useful predictive tools that enable welding technology development to keep pace with the deployment of new materials in various industrial sectors. Literature reviews showed two kinds of modeling activities. Academic and national laboratory efforts focus on developing integrated weld process models by employing the detailed scientific methodologies. However, these models are cumbersome and not easy to use. Therefore, these scientific models have limited application in real-world industrial conditions. On the other hand, industrial users have relied on simple predictive models based on analytical and empirical equations to drive their product development. The scopes of these simple models are limited. In this research, attempts were made to bridge this gap and provide the industry with a computational tool that combines the advantages of both approaches. This research resulted in the development of predictive tools which facilitate the development of optimized welding processes and consumables. The work demonstrated that it is possible to develop hybrid integrated models for relating the weld metal composition and process parameters to the performance of welds. In addition, these tools can be deployed for industrial users through user friendly graphical interface. In principle, the welding industry users can use these modular tools to guide their welding process parameter and consumable composition selection. It is hypothesized that by expanding these tools throughout welding industry

  4. Hybrid laser-gas metal arc welding (GMAW) of high strength steel gas transmission pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Harris, Ian D.; Norfolk, Mark I. [Edison Welding Institute (EWI), Columbus, Ohio (United States)

    2009-07-01

    Hybrid Laser/arc welding process (HLAW) can complete 5G welds, assure weld soundness, material properties, and an acceptable geometric profile. Combining new lasers and pulsed gas metal arc welding (GMAW-P) has led to important innovations in the HLAW process, increasing travel speed for successful root pass welding. High power Yb fiber lasers allow a 10 kW laser to be built the size of a refrigerator, allowing portability for use on the pipeline right-of-way. The objective was to develop and apply an innovative HLAW system for mechanized welding of high strength, high integrity, pipelines and develop 5G welding procedures for X80 and X100 pipe, including mechanical testing to API 1104. A cost-matched JIP developed a prototype HLAW head based on a commercially available bug and band system (CRC-Evans P450). Under the US Department of Transportation (DOT) project, the subject of this paper, the system was used to advance pipeline girth welding productivity. External hybrid root pass welding achieved full penetration welds with a 4-mm root at a travel speed of 2.3-m/min. Welds were made 'double down' using laser powers up to 10 kW and travel speeds up to 3-m/min. The final objective of the project was to demonstrate the hybrid LBW/GMAW system under simulated field conditions. (author)

  5. Advanced High Power DC-DC Converter using A Novel Type Voltage Source Full-Bridge Soft-Switching PWM Inverter with High Frequency Transformer Link for Arc Welding Applications

    Science.gov (United States)

    Morimoto, Keiki; Doi, Toshimitsu; Manabe, Haruhiko; Ahmed, Tarek; Hiraki, Eiji; Lee, Hyun-Woo; Nakaoka, Mutsuo

    This paper presents a new circuit topology of full-bridge soft-switching PWM inverter linked DC-DC power converter composed of conventional full-bridge high frequency PWM inverter with high frequency transformer and an active quasi-resonant snubber consisting of an additional power switching device in series with DC busline and a lossless capacitor in parallel with DC busline. Under this proposed high frequency soft-switching PWM inverter linked DC-DC converter, four power switches in the full-bridge arms and DC busline series switch can achieve ZVS at turn-off commutation. By developing the advanced soft-switching PWM high frequency inverter type DC-DC converter, although the conduction power loss of DC busline series power switch increases a little, the total turn-off switching loss of full-bridge high frequency inverter power modules can be sufficiently lowered more and more in the higher frequency range of 60kHz. As a result, when the switching frequency of high frequency inverter power stage using IGBT power modules is designed so as to be more than about 10kHz, the more the switching frequency of inverter increases, the more this high frequency soft-switching DC-DC converter has remarkable advantage as for the power conversion efficiency as compared with the conventional hard-switching PWM inverter DC-DC converter. Its practical effectiveness of high power density and high performance is actually proved for TIG arc welding equipment in industry.

  6. Imagining the Impossible: Revolutionary Critical Pedagogy Against the 21st Century American Imperium

    Directory of Open Access Journals (Sweden)

    Valerie Scatamburlo-D’Annibale

    2006-10-01

    Full Text Available This article examines some of the major Marxist-humanist themes that animate the revolutionary critical pedagogy delineated by Peter McLaren in recent years. Among these themes are radical universalism, an interrogation of the capitalization and commodification of human labor, and the interrelatedness of American imperialism and neoliberal globalized capitalism. It argues that McLaren’s scholarship provides progressive educationalists with an alternative to those “post-alized” and liberal humanist versions of critical pedagogy that have virtually abandoned all forms of class analysis. It contends that revolutionary critical pedagogy offers a much-needed narrative capable of challenging the most recent manifestations of empire, wars of aggression, and exploitative capitalist relations.

  7. Hybrid laser-arc welding

    DEFF Research Database (Denmark)

    Hybrid laser-arc welding (HLAW) is a combination of laser welding with arc welding that overcomes many of the shortfalls of both processes. This important book gives a comprehensive account of hybrid laser-arc welding technology and applications. The first part of the book reviews...... the characteristics of the process, including the properties of joints produced by hybrid laser-arc welding and ways of assessing weld quality. Part II discusses applications of the process to such metals as magnesium alloys, aluminium and steel as well as the use of hybrid laser-arc welding in such sectors as ship...... building and the automotive industry. With its distinguished editor and international team of contributors, Hybrid laser-arc welding, will be a valuable source of reference for all those using this important welding technology. Professor Flemming Ove Olsen works in the Department of Manufacturing...

  8. Imagining the Impossible: Revolutionary Critical Pedagogy Against the 21st Century American Imperium

    OpenAIRE

    Valerie Scatamburlo-D’Annibale

    2006-01-01

    This article examines some of the major Marxist-humanist themes that animate the revolutionary critical pedagogy delineated by Peter McLaren in recent years. Among these themes are radical universalism, an interrogation of the capitalization and commodification of human labor, and the interrelatedness of American imperialism and neoliberal globalized capitalism. It argues that McLaren’s scholarship provides progressive educationalists with an alternative to those “post-alized” and liberal h...

  9. The Revolutionary Armed Forces of Colombia (FARC) and the Development of Narco-Submarines

    OpenAIRE

    Michelle Jacome Jaramillo

    2016-01-01

    The Revolutionary Armed Forces of Colombia (FARC) have been one of the world's most consistently formidable violent non-state actors over the last forty years. Unsurprisingly, the group has provided one of the most compelling and concerning examples of the level of technical sophistication attainable by sub-state organizations. Over the last two decades the group has carried out an iterative and innovative process that, in reaction to improved detection capabilities, has brought them from dep...

  10. Revolutionary interdisciplinary cooperation. Effects of short- term regulation studied in a river environment

    Energy Technology Data Exchange (ETDEWEB)

    Saimakallio, H.; Virsu, R.

    1996-11-01

    A three-year study on how short-term regulation affects the river environment provides power plant builders with new capabilities to meet the needs of the riverside population, recreational users and power plants. The study also opens up new perspectives to researchers. Interdisciplinary cooperation between experts on the living environment, vegetation, fish, recreational use and energy has been revolutionary even on the international scale. (orig.)

  11. Alienation and Revolutionary Vision in East African Post-Colonial Dramatic Literature

    OpenAIRE

    Fashina, Nelson O.

    2009-01-01

    This paper is a trans-disciplinary inquiry into the principles of alienation and revolutionary ethos in two East African plays of postcolonial society. It engages literary-textual exegesis and sociological theories to unravel the multi-dimensional forms of alienation as an interrogation of contemporary postcolonial history. The writers, though somewhat in throes and dilemma of exilic consciousness, ‘commodify’ and appropriate the literary enterprise as weapon of active physical revolt and tex...

  12. Features Of The Local Government Development In Pre-Revolutionary Russia

    OpenAIRE

    Lyubov I. Rogacheva

    2014-01-01

    In the present article historical development of the municipal government institutes in the pre-revolutionary Russia are analyzed. Author emphasizes that in Russia at different stages of the statehood historical development a great experience of various forms and institutes of self-government were developed. History shows that municipal government in Russian conditions cannot develop in full in the conditions of weakening government. Without support of the strong state, municipal government h...

  13. About the Modern Historiography of the Pre-Revolutionary Period of Kiev Polytechnic Institute

    OpenAIRE

    M. STEPANOVA

    2016-01-01

    In this paper the problem of coverage of the Kiev Polytechnic Institute in prerevolutionary period in the recent period historiography. The problem of the origin and highlight the main achievements of the technical staff of the Kiev Polytechnic Institute in pre-revolutionary period shown on the basis of documentary and sources, works of a general nature. It is noted that in the recent period, new topics related to the initial period of the university. In these publications indicate veloped an...

  14. Induced Socio-economic Behavior in Long Waves : the Recurrence of Normal and Revolutionary Economic Science

    OpenAIRE

    Orley M. Amos Jr.; Edward O. Price III

    1991-01-01

    This research empirically examines the relationship between economic development and the progression of economic thought. It is based on three propositions: 1) economic development progresses by long waves, 2) long waves induce a cyclical pattern of general entrepreneurial and managerial socio-economic behavior, and 3) economists pursue alternating periods of revolutionary and normal economic science as part of the general socio-economic pattern of behavior. The general hypothesis of this stu...

  15. The investigation of mental health in post-revolutionary Iranian women

    OpenAIRE

    Shanghai, F.

    1998-01-01

    The aim of this thesis is "The Investigation of Mental Health, Family and Religion in Post-Revolutionary Iranian Women". This aim was initially outlined and explored in a Pilot Study, Study 1, which outlined narrative perspectives in the form of life histories as the methodological approach to be adopted whilst drawing on psychoanalytical theory, particularly object relations theory as its underlying theoretical construction. These methodological and theoretical approa...

  16. Revolutionaries, barbarians or war machines?; gangs in Nicaragua and South Africa

    OpenAIRE

    Rodgers, Dennis; Jensen, Steffen

    2008-01-01

    The view of gangs as proto-revolutionary vanguards has continued to inform the analyses of many gang researchers over the past few decades. During the course of our own research on gangs in respectively a poor neighbourhood in Managua, the capital city of Nicaragua, and a coloured township in Cape Town, South Africa, we have found considerable empirical resonance between Fanon's vision and the real-life discourses of many of the gangsters that we have interviewed and spent time with. Although...

  17. Smart KM Model: the integrated knowledge management revolutionary approach for organisational excellence

    OpenAIRE

    Ahmed, Allam; Elhag, Mohamed

    2014-01-01

    The seminar aims to introduce the newly developed Knowledge Management Model (SMART KM) which presents a unique integrated solution for the highly debated subject. SMART KM ensures that knowledge management becomes part of the organisational culture through the appropriate integration with number of organisation facets such as strategy, management systems, ICT and support services. SMART KM is a revolutionary model being driven by best-in-class KM practices from a number of industries in addi...

  18. Welding of tailored blanks of different materials

    OpenAIRE

    Suban, Marjan; Tušek, Janez; Kampuš, Zlatko

    2015-01-01

    This paper treats welding of tailored blanks made of different materials. In general, fusion welding and welding with pressure, practically without fusion, are described. Fusion welding may be carried out with or without the addition of filler material. In Section 3, general characteristics of tailored blanks are described. In Section 4, MIG welding and laser welding of austenitic stainless steel with ferrite non-stainless steel are described. After welding, hardness of the welded joints was ...

  19. Bypassing Islamism and Feminism: Women’s Resistance and Rebellion in Post-revolutionary Iran

    Directory of Open Access Journals (Sweden)

    Fatemeh Sadeghi

    2012-01-01

    Full Text Available This paper explores the reason behind the crisis of representation in post-revolutionary competing Iranian gender discourses. These competing discourses include Islamic fundamentalism, religious revisionism, and secular feminism. The crisis of representation is related to at least three main presuppositions and attendant action programs: first, discrimination against women and possible accommodations should be examined in the context of religious and legal institutions. This approach resulted in the depoliticization of women’s issues, even though most Iranian women have persistently proclaimed equality and citizenship through political participation. This was the case for the 1979 Islamic Revolution, the reform movement and most recently, the Green Movement following the 2009 presidential election. The second presupposition is that individual identity is a fundamental condition for socio-political activism. The third presupposition is that discrimination against women in post-revolutionary Iran is essentially a legalist strategy and has resulted in campaigns that failed to address women’s daily challenges. On the contrary, women’s political participation in post-revolutionary Iran shows that gender issues are always political issues and need to be understood politically and politicized. Such a notion challenges attitudes which relegate gender discrimination and social solutions to the purview of religion or secularism.

  20. Multispot fiber laser welding

    DEFF Research Database (Denmark)

    Schutt Hansen, Klaus

    This dissertation presents work and results achieved in the field of multi beam fiber laser welding. The project has had a practical approach, in which simulations and modelling have been kept at a minimum. Different methods to produce spot patterns with high power single mode fiber lasers have...... been examined and evaluated. It is found that both diamond turned DOE’s in zinc sulphide and multilevel etched DOE’s (Diffractive Optical Elements) in fused silica have a good performance. Welding with multiple beams in a butt joint configuration has been tested. Results are presented, showing it has...... in the weld causing expulsion of the melt pool. Trailing beams were applied to melt additional material and ensure a melt pool. The method showed good results for increasing tolerances to impurities and reduction of scrapped parts from blowouts during laser welding....

  1. Friction stir welding tool

    Science.gov (United States)

    Tolle; Charles R. , Clark; Denis E. , Barnes; Timothy A.

    2008-04-15

    A friction stir welding tool is described and which includes a shank portion; a shoulder portion which is releasably engageable with the shank portion; and a pin which is releasably engageable with the shoulder portion.

  2. Welding Qualification Sharing

    International Nuclear Information System (INIS)

    ASME Section IX, 'Welding Qualifications', requires that each organization qualify its own welders and welding procedures. Qualification responsibility cannot be subcontracted, and qualifications administered by one organization cannot be transferred to another organization. This requirement has become the subject of close scrutiny as the demand for efficiency, particularly among nuclear plant owners, has increased. Two recent Code Cases change procedure and performance qualification requirements for the better. The first, N-573, enables nuclear plant owners to share welding procedure qualifications. The second, N-600, enables nuclear plant owners to share welder performance qualifications. Several owners have reduced costs using N-573. N-600, because it is relatively new, has not yet been implemented. Its potential for cost savings, though, is equivalent to that afforded by N-573. This paper discusses ASME Section IX's procedure and performance qualification philosophy, assesses that philosophy in light of today's welding environment, and discusses implementation of Code Cases N-573 and N-600. (authors)

  3. Laser welding of venotomies.

    Science.gov (United States)

    White, R A; Abergel, R P; Klein, S R; Kopchok, G; Dwyer, R M; Uitto, J

    1986-08-01

    We investigated the histologic and biochemical effects of carbon dioxide and neodymium (Nd)-YAG laser welding on the healing of venotomies. Ten canine femoral venotomies 2 cm in length were approximated and welded with 10 600-nm wavelength, 1-W power over 20 to 25 s for CO2 laser, and 1060-nm wavelength, 1-W power over 30 to 40 s for Nd-YAG laser. On removal at one to three weeks, all veins (4/4 welded by CO2 and 6/6 by Nd-YAG) were patent without hematomas. Histologic and biochemical analyses of the venous tissues demonstrated active healing at the venotomy sites. We conclude that the CO2 and Nd-YAG lasers can be used successfully to weld venotomies and may provide an alternative to conventional suture techniques for repair of vascular lesions. PMID:3089196

  4. Magnetic Pulse Welding Technology

    Directory of Open Access Journals (Sweden)

    Ahmad K. Jassim

    2011-12-01

    Full Text Available In this paper, the benefits of using Magnetic Pulse machine which is belong to Non-conventional machine instead of conventional machine. Magnetic Pulse Technology is used for joining dissimilar metals, and for forming and cutting metals. It is a non contact technique. Magnetic field is used to generate impact magnetic pressure for welding and forming the work piece by converted the electrical energy to mechanical energy. It is enable us to design previously not possible by welding dissimilar materials and allowing to welds light and stronger materials together. It can be used to weld metallic with non metallic materials to created mechanical lock on ceramics, polymers, rubbers and composites. It is green process; there is no heat, no radiation, no gas, no smoke and sparks, therefore the emissions are negligible.

  5. Welding of refractory alloys

    International Nuclear Information System (INIS)

    This review primarily summarizes welding evaluations supported by NASA-Lewis Research Center in the 1960s. A literature search run in preparation for this review indicates that more recent work is modest by comparison. Hence, this review restates these accomplishments briefly and addresses opportunities which have evolved in welding technology (such as lasers) in the intervening decade. Emphasis in this review is given to tantalum- and niobium-base alloys. Considerable work was also done to assure that a consistent comparison was made with tungsten. A wide variety of candidate alloys derived primarily from developments directed at aircraft propulsion applications were available. Early efforts by NASA were directed at screening studies to select promising structural alloys for the space power application. This objective required fine tuning of welding procedures, e.g., the demonstration of stringent standards for control of welding atmosphere to assure good corrosion resistance in liquid alkali metals. 16 figures, 6 tables

  6. LASER NET SHAPE WELDING OF STEELS

    OpenAIRE

    Eghlio, Ramadan Mahmoud

    2012-01-01

    Laser technologies have made distinguished contributions to modern industry. These have typically been realised through the important role played by lasers in the advancement of manufacturing technology in many areas such as welding, which has become an important joining technique and thus promoted the use of lasers in a wide variety of applications in the oil, gas, aerospace, aircraft, automotive, electronics and medical industries.A detailed review of previous work in the use of lasers for ...

  7. Customized orbital welding meets the challenge of titanium welding

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-01

    Titanium has emerged as the material of choice for tubing used in surface condensers around the world in both new and retrofit configurations. A major worldwide supplier of steam surface condensers to the electric utility industry, Senior Engineering is finding an increased use of titanium tubes and tube sheets in condenser specifications. When compared to other alloys, titanium`s light weight is efficient in design, handling, transportation and installation activities. Additionally, it maintains a stable price structure. Senior Engineering implements an orbital welding process using fusion gas tungsten arc welding (GTAW) for its titanium tube-to-tube sheet welding. Orbital welding involves the use of a welding apparatus placed inside a tube or pipe to automatically and precisely weld a 360-deg joint. When welding manually, a welder stops several times during the weld due to the large amount of time and fatigue involved in achieving 360-deg welds, which results in lack of fusion. An automated orbital welding system, however, can accomplish the task as one continuous weld. This reduces process time and decreases lack of fusion. The orbital welding systems, featuring a microprocessor-based controller, an inverter-based power supply, an expandable mandrel and a customized torch shroud, reduced welding labor by 35%. The improved labor efficiency justified the addition of two more of the systems in January 1996.

  8. Customized orbital welding meets the challenge of titanium welding

    International Nuclear Information System (INIS)

    Titanium has emerged as the material of choice for tubing used in surface condensers around the world in both new and retrofit configurations. A major worldwide supplier of steam surface condensers to the electric utility industry, Senior Engineering is finding an increased use of titanium tubes and tube sheets in condenser specifications. When compared to other alloys, titanium's light weight is efficient in design, handling, transportation and installation activities. Additionally, it maintains a stable price structure. Senior Engineering implements an orbital welding process using fusion gas tungsten arc welding (GTAW) for its titanium tube-to-tube sheet welding. Orbital welding involves the use of a welding apparatus placed inside a tube or pipe to automatically and precisely weld a 360-deg joint. When welding manually, a welder stops several times during the weld due to the large amount of time and fatigue involved in achieving 360-deg welds, which results in lack of fusion. An automated orbital welding system, however, can accomplish the task as one continuous weld. This reduces process time and decreases lack of fusion. The orbital welding systems, featuring a microprocessor-based controller, an inverter-based power supply, an expandable mandrel and a customized torch shroud, reduced welding labor by 35%. The improved labor efficiency justified the addition of two more of the systems in January 1996

  9. Numerical simulation of welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær; Thorborg, Jesper

    , good predictions of the thermal field are obtained. This has been verified with experiments. The significance of the right fitting of the model to the topical welding process must be emphasized. With a mechanical model in ABAQUS based on a thermal model as described, distributions of both transient...... welding process. Various circumstances are process dependent and require not only knowledge of the process in practice butalso a thorough experience with the numerical modelling of the problem....

  10. Magnetic Pulse Welding Technology

    OpenAIRE

    Ahmad K. Jassim

    2011-01-01

    In this paper, the benefits of using Magnetic Pulse machine which is belong to Non-conventional machine instead of conventional machine. Magnetic Pulse Technology is used for joining dissimilar metals, and for forming and cutting metals. It is a non contact technique. Magnetic field is used to generate impact magnetic pressure for welding and forming the work piece by converted the electrical energy to mechanical energy. It is enable us to design previously not possible by weld...

  11. Friction Stir Weld Tools

    Science.gov (United States)

    Carter, Robert W. (Inventor); Payton, Lewis N. (Inventor)

    2007-01-01

    A friction stir weld tool sleeve is supported by an underlying support pin. The pin material is preferably selected for toughness and fracture characteristics. The pin sleeve preferably has a geometry which employs the use of an interrupted thread, a plurality of flutes and/or eccentric path to provide greater flow through. Paddles have been found to assist in imparting friction and directing plastic metal during the welding process.

  12. Welding unit - Metallurgical Research Department

    International Nuclear Information System (INIS)

    This report reviews the activities of the Metallurgical Research Department's Welding Unit during 1984. Major research programs during the year included nuclear waste container welding, pulsed-current gas-metal-arc welding procedure development, welding automation and robotics, and repair welding technology, particularly temperbead. Smaller research projects, and the substantial amount of field support and service work performed in 1984, are also summarized. Reports issued by the Welding Unit, as well as externally published papers and presentations are listed. Finally, the proposed activities and objectives for the Unit's 1985 work program are outlined, with particular reference to the major research areas carrying on from 1984

  13. Stress corrosion cracking of austenitic stainless steel core internal weld

    International Nuclear Information System (INIS)

    Microstructural analyses by several advanced metallographic techniques were conducted on austenitic stainless steel mockup and core shroud welds that cracked in boiling water reactors. Contrary to previous beliefs, heat-affected zones of the cracked Type 304L as well as 304 SS core shroud welds and mockup shielded-metal-arc welds were free of grain-boundary carbides, which shows that core shroud failure cannot be explained by classical intergranular stress corrosion cracking. Neither martensite nor delta-ferrite films were present on grain boundaries. However, as a result of exposure to weld fumes, the heat-affected zones of the core shroud welds were significantly contaminated by oxygen and fluorine which migrate to grain boundaries. Significant oxygen contamination seems to promote fluorine contamination and suppress thermal sensitization. Results of slow-strain-rate tensile tests indicate also that fluorine exacerbate the susceptibility of irradiated steels to intergranular stress corrosion cracking. These observations, combined with previous reports on the strong influence of weld flux, indicate that oxygen and fluorine contamination and fluorine-catalyzed stress corrosion play a major role in cracking of core shroud welds

  14. Development of Design Software for Weld Overlay of Pressurizer

    Energy Technology Data Exchange (ETDEWEB)

    Byeon, J. G.; Lee, J. B.; Park, K. S. [Doosan Heavy Industries and Construction Co., Seoul (Korea, Republic of)

    2010-05-15

    As a result of Primary Water Stress Corrosion Cracking (PWSCC) in alloy 600, leaks in dissimilar metal weld (DMW) of pressurizer nozzles were discovered recently in several US plants. The involved companies developed advanced repair techniques to prevent or repair PWSCC applying weld overlay procedures to dissimilar metal welds such as those between pipes and nozzles. Within 2 or 3 years, more than half of the nuclear power plants in Korea will have been in operation for more than 20 years. The weld overlay technology consists of overlay design, design and manufacturing of welding system and procedures. DMW zone in pressurized nozzles has different shapes and sizes. If shape and size of DMW zone in pressurized nozzles is different, the overlay design will be performed again. The welding system also will be designed and manufactured each types of nozzle. In order to minimize the similar works, related tool will be needed. From this background, the 3D Simulation software, dNOSS (doosan NSSS Overlay 3D Simulation Software), has been developed to apply full structural weld overlay for DMW

  15. Weld overlay repairs from conception to long-term qualification

    International Nuclear Information System (INIS)

    Weld overlay repairs serve several design functions. These include: structurally reinforcing the flawed location to restore code margins to failure, providing an IGSCC-resistant barrier to crack growth, and imposing a favorable residual stress distribution in the inner portion of the flawed component to inhibit further flaw initiation and growth. The qualification programs confirm that these design functions are maintained with long-term service. A regulatory barrier to long-term operation with weld overlays was the need periodically to inspect overlays and thereby demonstrate continued integrity. Although IGSCC flaws have generally been detected by ultrasonic methods, the repair of these flaws by weld overlay made continued monitoring of the repaired flaw by conventional ultrasonic techniques difficult. Recent developments in ultrasonic examination equipment and techniques, including surface preparation criteria, have enhanced the inspectability of weld overlay repairs and the underlying base material. The original acceptance of weld overlay repairs by the USNRC was for limited service (one or two fuel cycles of operation). However, more recent regulatory guidance, including the recently issued NUREG-0313, Revision 2, recognizes the above technical advances, and provides criteria for acceptance of weld overlays as long-term repairs. Several US utilities have been successful to date in obtaining USNRC approval for extended operation with weld overlays. Some overlays at these plants are currently entering their fourth successful fuel cycle of operation. (author)

  16. Application of AMI 207A automatic welding to the erection engineering of electric instrument tube of nuclear powre plant

    International Nuclear Information System (INIS)

    The industrial application of automatic, intelligent and high-precision parameter-controlled welding equipment has become true long age in the western developed countries. However, this kind of equipment has been seldom used in China, especially on the erection site of nuclear power construction. In the Phase III of Qinshan Nuclear Power Project, we used the American AMI (Arc Machines, Inc.) 208A automatic welding equipment and technology to have all grooves of the electric instrument tubes automatically welded. The practice has proved that the automatic welding is more advanced, highly effective and more economic compared with other welding processes. (authors)

  17. Precipitation of Niobium Boride Phases at the Base Metal/Weld Metal Interface in Dissimilar Weld Joints

    Science.gov (United States)

    Výrostková, Anna; Kepič, Ján; Homolová, Viera; Falat, Ladislav

    2015-07-01

    In this work, the analysis of failure mechanism in the heat affected zone is described in dissimilar weld joints between advanced martensitic steel T92 and Ni-base weld metal. The joints were treated with two different post-weld heat treatments and tested. For the creep, tensile, and Charpy impact tests, the samples with interfacially located notch were used. Moreover long term aging at 625 °C was applied before the tensile and notch toughness tests. Decohesion fractures ran along carbides at the T92 BM/WM interfaces in case of the modified PWHT, whereas type IV cracking was the prevailing failure mechanism after the classical PWHT in the creep test. In the notch tensile and Charpy impact tests, with the notch at T92 base metal/weld metal interface, fractures ran along the interface with a hard phase on the fracture surface along with the ductile dimple and brittle quasi-cleavage fracture. The phase identified as niobium boride (either NbB and/or Nb3B2) was produced during welding at the end of the solidification process. It was found in the welds regardless of the post-weld heat treatment and long-term aging.

  18. Fluid Flow Phenomena during Welding

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wei [ORNL

    2011-01-01

    MOLTEN WELD POOLS are dynamic. Liquid in the weld pool in acted on by several strong forces, which can result in high-velocity fluid motion. Fluid flow velocities exceeding 1 m/s (3.3 ft/s) have been observed in gas tungsten arc (GTA) welds under ordinary welding conditions, and higher velocities have been measured in submerged arc welds. Fluid flow is important because it affects weld shape and is related to the formation of a variety of weld defects. Moving liquid transports heat and often dominates heat transport in the weld pool. Because heat transport by mass flow depends on the direction and speed of fluid motion, weld pool shape can differ dramatically from that predicted by conductive heat flow. Temperature gradients are also altered by fluid flow, which can affect weld microstructure. A number of defects in GTA welds have been attributed to fluid flow or changes in fluid flow, including lack of penetration, top bead roughness, humped beads, finger penetration, and undercutting. Instabilities in the liquid film around the keyhole in electron beam and laser welds are responsible for the uneven penetration (spiking) characteristic of these types of welds.

  19. WELD FORMATION CONTROL AT ELECTRON BEAM WELDING WITH BEAM OSCILLATIONS

    OpenAIRE

    Trushnikov, Dmitriy; Koleva, Elena; Mladenov, Georgy; Shcherbakov, A.

    2014-01-01

    Electron beam welding is used extensively to produce essential machine parts. The control of the basic beam parameters beam power or beam current at constant accelerating voltage, welding speed, current of focusing lens and distance between electron gun and welded sample surface is not enough to obtain at most of the regimes sound welds. Control of the focus position using analysis of the high frequency component of the current, collected by plasma, at periodic interactions on the beam (the o...

  20. Welding in Space: Lessons Learned for Future In Space Repair Development

    Science.gov (United States)

    Russell, C. K.; Nunes, A. C.; Zimmerman, F. R.

    2005-01-01

    Welds have been made in the harsh environment of space only twice in the history of manned space flight. The United States conducted the M5 12 experiment on Skylab and the former Soviet Union conducted an Extravehicular Activity. Both experiments demonstrated electron beam welding. A third attempt to demonstrate and advance space welding was made by the Marshall Space Flight Center in the 90's but the experiment was demanifested as a Space Shuttle payload. This presentation summarizes the lessons learned from these three historical experiences in the areas of safety, design, operations and implementation so that welding in space can become an option for in space repair applications.

  1. A new welding technique for stainless steel pipe butt welds

    International Nuclear Information System (INIS)

    A modified TIG welding process which uses an accurately machined consumable weld socket ring for aligning pipes and providing filler material has been developed by British Nuclear Fuels and used successfully at Windscale Site Construction. The technique and its practical application at Windscale for automatic orbital TIG welding of stainless steel pipe is described. (author)

  2. Microscopic weld evaluation of FBTR end plug welds

    International Nuclear Information System (INIS)

    SS316 Stainless steel has been chosen as a reference cladding material for Fast Breeder Test Reactor. Both the ends of the clad tubes are encapped with a solid stainless steel plug by Tungsten Inert Gas welding processes. Due to the thick-thin geometry of the end plug and the fuel clad tube, getting defect free weld joint is a challenging task. Microscopic weld evaluation of the weld defects of these end plug welds have been carried out as per standard ASTM metallography practice. Requirement of the good quality weld joint is very essential to contain the fission gas release and to enable it to sustain the high burn up of the fuel in the nuclear reactor. This paper presents the typical weld defects encountered during the development and fabrication of the actual fuel pin and it also shows some of the weld characteristics like multiple weld pool, spherical weld pool, through and through weld penetration, outer edge depression at the tube side and the plug side of the weld pool observed during the pin fabrication campaign. (author)

  3. JPL Advanced Thermal Control Technology Roadmap - 2012

    Science.gov (United States)

    Birur, Gaj; Rodriguez, Jose I.

    2012-01-01

    NASA's new emphasis on human exploration program for missions beyond LEO requires development of innovative and revolutionary technologies. Thermal control requirements of future NASA science instruments and missions are very challenging and require advanced thermal control technologies. Limited resources requires organizations to cooperate and collaborate; government, industry, universities all need to work together for the successful development of these technologies.

  4. Ultrasonic inspection of austenitic welds

    International Nuclear Information System (INIS)

    The ultrasonic examination of austenitic stainless steel weld metal has always been regarded as a difficult proposition because of the large and variable ultrasonic attenuations and back scattering obtained from apparently similar weld deposits. The work to be described shows how the existence of a fibre texture within each weld deposit (as a result of epitaxial growth through successive weld beads) produces a systematic variation in the ultrasonic attenuation coefficient and the velocity of sound, depending upon the angle between the ultrasonic beam and the fibre axis. Development work has shown that it is possible to adjust the welding parameters to ensure that the crystallographic texture within each weld is compatible with improved ultrasonic transmission. The application of the results to the inspection of a specific weld in type 316 weld metal is described

  5. Laser welding of cylindrical parts

    OpenAIRE

    Närhi-Ratkovskaia, Olga

    2011-01-01

    The purpose of this paper is to conduct the laser welding work of the cylindrical parts, particularly fuel filters, according to the safety instructions. The welding was followed by the additional test for a gas resistance of filters. The topic was commissioned by the company Laserplus Oy, located in Hämeenlinna. The aim of the project on laser welding of filters was to find out optimum parameters for the company’s welding. Optimum parameters include the minimum laser power with optimum ...

  6. Creep of welded branched pipes

    OpenAIRE

    Rayner, Glen

    2004-01-01

    Creep failure of welds in high-temperature power plant steam piping systems is known to be a potential cause of plant failure. Creep behaviour of plain pipes with circumferential welds and cross-weld specimens have received fairly extensive attention. However, research into the creep behaviour of welded thick-walled branched steam pipes has received less attention. Consequently, this thesis addresses improving the understanding of the creep behaviour for this type of geometry. Numerical and a...

  7. Multipass autogenous electron beam welding

    International Nuclear Information System (INIS)

    A multipass, autogenous welding procedure was developed for 7.6 mm (0.3 in.) wall thickness Type 304L stainless steel cylinders. The joint geometry has a 1.5 mm (0.06 in.) root-face width and a rectangular stepped groove that is 0.762 mm (0.03 in.) wide at the top of the root face and extends 1.5 mm in height, terminating into a groove width of 1.27 mm which extends to the outside of the 1.27 mm high weld-boss. One weld pass is made on the root, three passes on the 0.762 mm wide groove and three passes to complete the weld. Multipass, autogenous, electron beam welds maintain the characteristic high depth-to-width ratios and low heat input of single-pass, electron beam welds. The increased part distortion (which is still much less than from arc processes) in multipass weldments is corrected by a preweld machined compensation. Mechanical properties of multipass welds compare well with single-pass welds. The yield strength of welds in aluminum alloy 5083 is approximately the same for single-pass or multipass electron beam and gas, metal-arc welds. The incidence and size of porosity is less in multipass electron beam welding of aluminum as compared to gas, metal-arc welds. The multipass, autogenous, electron beam welding method has proven to be a reliable way to make some difficult welds in multilayer parts or in an instance where inside part temperature or weld underbead must be controlled and weld discontinuities must be minimized

  8. A study of electron beam welding of Mo based TZM alloy

    International Nuclear Information System (INIS)

    Mo based TZM alloy is one of the most promising refractory alloy having several unique high temperature properties suitable for structural applications in the new generation advanced nuclear reactors. However, this alloy easily picks up interstitial impurities such as N2, H2 and C from air during welding due to its reactive nature. High melting point of TZM alloy also restricts use of conventional welding technique for welding. Hence, Electron beam welding (EBW) technique with its deep penetration power to produce narrow heat affected zones under high vacuum was employed to overcome the above welding constraints by conducting a systematic study using both processes of bead on plate and butt joint configuration. Uniform and defect free weld joints were produced. Weld joints were subjected to optical characterization, chemical homogeneity analysis and microhardness profile study across the width of welds. Improved grain structure with equiaxed grains was obtained in the weld zone as compared to fibrous base structure. Original chemical composition was retained in the weld zone. The detailed results are described in this report. (author)

  9. Natural aging in friction stir welded 7136-T76 aluminum alloy

    International Nuclear Information System (INIS)

    Highlights: • The study sheds new light on the natural aging of AA7136 friction stir welds. • Natural aging notably influences the mechanical properties of friction stir welds. • The hardness profile can be correlated to the temperature distribution model. • The GP(I) zones formation is responsible for the increased mechanical properties. • Natural aging cannot be neglected in practical applications of the FSW process. - Abstract: The long term natural aging behavior of friction stir welded aluminum 7136-T76 extrusions was investigated. The microstructural characteristics and mechanical properties in the as-welded, three years naturally aged and six years naturally aged conditions were studied and correlated to a coupled thermal/material flow model of the joining process. Hardness profiles taken along the mid-plane thickness of the workpiece displayed the characteristic W-shape typical to friction stir welded aluminum alloys. In the as-welded condition, however, the profile was skewed to the advancing side, such that the advancing side hardness was lower than that on the retreating side. With natural aging, hardness recovery occurred on both sides of the weld, but the position of the hardness minima, particularly on the advancing side, shifted away from the weld centerline. The numerical simulation demonstrated that the temperature profile is also skewed to the advancing side with greater processing temperatures occurring on this side of the weld. When compared to the dissolution temperature of the equilibrium phases, the extent of dissolution was greater on the advancing side and occurred to a greater distance from the centerline than on the retreating side. The hardness behavior upon natural aging, therefore, correlated to the temperature profile developed during welding and the degree to which phase dissolution occurred in the regions adjacent to the stir zone

  10. Welding. Performance Objectives. Basic Course.

    Science.gov (United States)

    Vincent, Kenneth

    Several intermediate performance objectives and corresponding criterion measures are listed for each of eight terminal objectives for a basic welding course. The materials were developed for a 36-week (2 hours daily) course developed to teach the fundamentals of welding shop work, to become familiar with the operation of the welding shop…

  11. Welding. Performance Objectives. Intermediate Course.

    Science.gov (United States)

    Vincent, Kenneth

    Several intermediate performance objectives and corresponding criterion measures are listed for each of nine terminal objectives for an intermediate welding course. The materials were developed for a 36-week (3 hours daily) course designed to prepare the student for employment in the field of welding. Electric welding and specialized (TIG & MIG)…

  12. Laser welding engineering

    International Nuclear Information System (INIS)

    Laser welding was in its early life used mainly for unusual applications where no other welding process would be suitable that was twenty five years ago. Today, laser welding is a fully developed part of the metal working industry, routinely producing welds for common items such as cigarette lighters, which springs, motor/transformer lamination, hermetic seals, battery and pacemaker cans and hybrid circuit packages. Yet very few manufacturing engineering have seriously considers employing lasers in their own operations. Why? There are many reasons, but a main one must be not acquainted with the operation and capabilities of a laser system. Other reasons, such as a relatively high initial cost and a concern about using lasers in the manufacturing environment, also are frequently cited, and the complexity of the component and flexibility of the light delivery system. Laser welding could be used in place of many different standard processes, such as resistance (spot or seam), submerged arc, RF induction, high-frequency resistance, ultrasonic and electronic and electron-beam. while each of these techniques has established an independent function in the manufacturing world, the flexible laser welding approach will operate efficiently and economically in many different applications. Its flexibility will even permit the welding system to be used for other machining function, such as drilling, scribing, sealing and serializing. In this article, we will look at how laser welding works and what benefits it can offer to manufacturing engineers. Some industry observers state that there are already 2,000 laser machine tools being used for cutting, welding and drilling and that the number could reach 30,000 over the next 15 years as manufacturing engineers become more aware of the capabilities of lasers [1). While most laser applications are dedicated to one product or process that involves high-volume, long-run manufacturing, the flexibility of a laser to supply energy to hard

  13. Friction stir welding tool and process for welding dissimilar materials

    Science.gov (United States)

    Hovanski, Yuri; Grant, Glenn J; Jana, Saumyadeep; Mattlin, Karl F

    2013-05-07

    A friction stir welding tool and process for lap welding dissimilar materials are detailed. The invention includes a cutter scribe that penetrates and extrudes a first material of a lap weld stack to a preselected depth and further cuts a second material to provide a beneficial geometry defined by a plurality of mechanically interlocking features. The tool backfills the interlocking features generating a lap weld across the length of the interface between the dissimilar materials that enhances the shear strength of the lap weld.

  14. Integrated sensors for robotic laser welding

    OpenAIRE

    Iakovou, D.; Aarts, R.G.K.M.; Meijer, J.; Beyer, E.; Dausinger, F.; Ostendorf, A.; Otto, A.

    2005-01-01

    A welding head is under development with integrated sensory systems for robotic laser welding applications. Robotic laser welding requires sensory systems that are capable to accurately guide the welding head over a seam in three-dimensional space and provide information about the welding process as well as the quality of the welding result. In this paper the focus is on seam tracking. It is difficult to measure three-dimensional parameters of a ream during a robotic laser welding task, espec...

  15. Comparing weld inspection codes: radiography vs. ultrasonics

    International Nuclear Information System (INIS)

    Requirements for weld quality are continually increasing. This is due to a combination of factors: increased public awareness; bigger legal penalties; improved and thinner steels; better analysis techniques such as Engineering Critical Assessment (ECA); higher material costs. Weld quality is primarily dictated by construction codes, which should reflect the needs of society and industry: safety, the environment, society, and cost-effectiveness. As R and D produces new products, techniques and procedures, ideally these developments should be reflected in the codes. While pressure vessel and structural welding are certainly included here, it is really pipeline weld inspections that are setting the pace on new developments. For pipelines, a major shift was made from radiography to ultrasonics in Alberta some decades ago. This was driven by the 'need for speed', plus the requirement to size defects in the vertical plane for ECA (also called Fracture Mechanics or Fitness-For-Purpose). One of the main objectives of ECA was to benefit from the calculated fracture toughness of materials, and not to rely on the overly conservative workmanship criteria in radiography. In practice, performing repairs on higher quality material often does more harm than good; changing the microstructure can seriously compromise the material properties. Rising steel costs are another major driving force, so higher strength, thinner materials are being used. Under these conditions, ECA and defect sizing are critical. This paper compares where the various North American codes for pipelines, pressure vessels and structural welds stand on using advanced inspection techniques: ultrasonics, phased arrays, ECA, sizing techniques. For those codes which are not using the latest technologies, there are typical routes for incorporating them. (author)

  16. Control of weld quality in large welded populations

    International Nuclear Information System (INIS)

    The use of factorial experimental design during weld procedure development, as a statistical tool for the control of weld quality in large welded populations, is investigated. As an example, it is applied to single pass welds made in the laboratory using the spacer to tube attachment geometry present in AGR boilers. The welds have been deposited using a robotic cold wire TIG technique. A replicated 25 factorial welding trial has been designed and evaluated experimentally. Transverse sections have been examined to determine weld penetration quality features. The means and variances of each quality feature have been calculated. Using a standard factorial analysis program the significant effects have been identified and incorporated into control equations. Using these data and having established minimum acceptance criteria. defect rates have been calculated as a function of weld position. The control equations have also been used to revise working point welding conditions, to achieve acceptable weld quality. These equations have also been used in conjunction with the reproducibility measurements to estimate the amount of weld quality variability that can be attributed to process control. (author)

  17. False, trivial, obvious: why new and revolutionary theories are typically disrespected.

    Science.gov (United States)

    Charlton, Bruce G

    2008-01-01

    An old joke about the response to revolutionary new scientific theories states that there are three phases on the road to acceptance: 1. The theory is not true; 2. The theory is true, but it is unimportant; 3. The theory is true, and it is important - but we knew it all along. The point of this joke is that (according to scientific theorists) new theories are never properly appreciated. The 'false' phase happens because a defining feature of a revolutionary theory is that it contradicts the assumptions of already-existing mainstream theory. The second 'trivial' phase follows from a preliminary analysis which suggests that the new idea is not in fact contradicted by the major existing evidence, but the new theory seems unimportant because its implications do not seem to lead anywhere interesting when explored in the light of current theory. A stronger version of this second phase happens when the implications of a theory are regarded as not merely unimportant but actually dangerous, because a scientific revolution is certainly destructive (especially of established reputations) yet its potential benefits are conjectural. However, once a new and revolutionary theory is in place, its importance is 'obvious' such that it becomes hard to imagine how anybody could ever have believed anything else. Theory for scientists is like water for fish: the invisible medium in which they swim. Observations and experiments, on the other hand, are like toys in the fish tank. New toys are attention-grabbing; but when the tank gets cloudy, its water needs changing. PMID:18434041

  18. Weld pool image sensor for pulsed MIG welding

    Institute of Scientific and Technical Information of China (English)

    Liu Pengfei; Sun Zhenguo; Huang Cao; Chen Qiang

    2008-01-01

    Visual image sensor is developed to detect the weld pool images in pulsed MIG welding. An exposure controller, which is composed of the modules of the voltage transforming, the exposure parameters presetting, the complex programmable logic device (CPLD) based logic controlling, exposure signal processing, the arc state detecting, the mechanical iris driving and so on, is designed at first. Then, a visual image sensor consists of an ordinary CCD camera, optical system and exposure controller is established. The exposure synchronic control logic is described with very-high-speed integrated circuit hardware description language (VHDL) and programmed with CPLD, to detect weld pool images at the stage of base current in pulsed MIG welding. Finally, both bead on plate welding and V groove filled welding are carried out, clear and consistent weld pool images are acquired.

  19. Weld Nugget Temperature Control in Thermal Stir Welding

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2014-01-01

    A control system for a thermal stir welding system is provided. The control system includes a sensor and a controller. The sensor is coupled to the welding system's containment plate assembly and generates signals indicative of temperature of a region adjacent and parallel to the welding system's stir rod. The controller is coupled to the sensor and generates at least one control signal using the sensor signals indicative of temperature. The controller is also coupled to the welding system such that at least one of rotational speed of the stir rod, heat supplied by the welding system's induction heater, and feed speed of the welding system's weld material feeder are controlled based on the control signal(s).

  20. Welding Molecular Crystals.

    Science.gov (United States)

    Adolf, Cyril R R; Ferlay, Sylvie; Kyritsakas, Nathalie; Hosseini, Mir Wais

    2015-12-16

    Both for fundamental and applied sciences, the design of complex molecular systems in the crystalline phase with strict control of order and periodicity at both microscopic and macroscopic levels is of prime importance for development of new solid-state materials and devices. The design and fabrication of complex crystalline systems as networks of crystals displaying task-specific properties is a step toward smart materials. Here we report on isostructural and almost isometric molecular crystals of different colors, their use for fabrication of core-shell crystals, and their welding by 3D epitaxial growth into networks of crystals as single-crystalline entities. Welding of crystals by self-assembly processes into macroscopic networks of crystals is a powerful strategy for the design of hierarchically organized periodic complex architectures composed of different subdomains displaying targeted characteristics. Crystal welding may be regarded as a first step toward the design of new hierarchically organized complex crystalline systems. PMID:26581391

  1. John Punch, Scotist Holy War, and the Irish Catholic Revolutionary Tradition in the Seventeenth Century.

    Science.gov (United States)

    Campbell, Ian W

    2016-07-01

    During the 1640s, the Irish Franciscan theologian John Punch taught his theology students in Rome that war against Protestants was made just by their religion alone. Jesuits like Luis de Molina identified the holy war tradition in which Punch stood as a Scotist one, and insisted that the Scotists had confused the natural and supernatural spheres. Among Irishmen, Punch was unusual. The main Irish Catholic revolutionary tradition employed Jesuit and Thomist theory. They argued that the Stuarts had lost the right to rule Ireland for natural reasons, not supernatural ones; because the Stuarts were tyrants, not because they were Protestants. PMID:27477343

  2. Treatment of cleft lip and palate during the Revolutionary war: bicentennial reflections.

    Science.gov (United States)

    Rogers, B O

    1976-10-01

    Cleft palate surgery was not performed either in Europe or in America during the time of America's Revolutionary War. Cleft lip surgery was performed by the pinning and figure-of-eight thread method of closure in keeping with current European teachings on the subjects. This surgery was frequently performed by itinerant mendicants, charlatans, and also by the more legitimate members of the surgical community living in the 13 states at the time of the Revolution. A brief review of the surgical methods employed form the major portion of the article. PMID:786505

  3. THE CONTRIBUTION MADE BY T.E. LAWRENCE TO THE THEORY OF REVOLUTIONARY WARFARE

    Directory of Open Access Journals (Sweden)

    G.K.B. Barron

    2012-02-01

    Full Text Available Lawrence was basically an academic thrown into the hurly-burly of leading an Arab revolt against Turkish domination. It could be said that the war in the Middle East was a sideshow of the First World War and Lawrence's part was a ' ... sideshow to the sideshow'l Why then has Lawrence been remembered when greater military men have been forgotten? The romanticism of his exploits are surely the reason, and yet the fact that he is the first modern theorist and possibly the "father" of modern revolutionary warfare, tends to be forgotten.

  4. Effect of tool centreline deviation on the mechanical properties of friction stir welded DH36 steel

    International Nuclear Information System (INIS)

    Highlights: • FSW of DH36 was tolerant to a centreline defect induced by tool deviation. • High strength welds up to 2.5 mm centreline tool deviation with ductile PM fracture. • Critical tolerance to centreline tool deviation at 4 mm with ductile weld metal fracture. • Brittle fracture above 4 mm deviation led to significant reduction in yield strength. - Abstract: Friction stir welding of steel has gone through recent tool and optimisation developments allowing the process to be considered as a technically superior alternative to fusion welding. This study expanded the scientific foundation of friction stir welding of DH36 steel to analyse the effect on weld quality when the rotating tool increasingly deviates away from the weld centreline. A centreline defect was deliberately but gradually introduced along the length of the weld seam. The tolerance to tool deviation towards both the advancing side and the retreating side of the weld was measured in terms of the transverse yield strength. Three discrete fracture modes were observed in transverse tensile specimen. Up to a tool deviation of 2.5 mm, ductile fracture in the parent material was observed and there was not a significant reduction in the yield strength of the weldment. The critical tool deviation occurred at 4 mm, where transverse tensile specimens fractured in a high strength ductile mode in the weld metal. Brittle behaviour in specimens above the 4 mm tolerance level resulted in a significant decrease in the transverse yield strength. Fracture within the weld metal was directed along the boundary between the heat-affected zone and thermo-mechanically affected zone, attributable to an abrupt change in the grain size and complexity of the two weld zones at this boundary. Friction stir welding of DH36 was found to be a tolerant joining process to the centreline deviation of the rotating tool

  5. Hybrid laser-Metal Inert Gas welding of Al–Mg–Si alloy joints: Microstructure and mechanical properties

    International Nuclear Information System (INIS)

    Highlights: • Microstructure and mechanical properties of the welded joint have been investigated. • Reasons for the strength loss of the welded joint have been discussed. • The distribution of strengthening elements has been obtained using synchroton radiation X-rays. - Abstract: Hybrid fiber laser-Metal Inert Gas (MIG) welding is an advanced joining technology that is increasingly employed in the modern industry. In this paper, hybrid fiber laser-MIG welding was applied to join 5 mm thick AA6005-T5 alloy used in the carbody of high-speed railway vehicles. The mechanical properties of the hybrid welded joints were investigated. The results showed that the hybrid welded joints have more excellent mechanical properties than that of the MIG joints. However, there is still strength loss in the hybrid welded joins comparing with the base metal. The reason for the loss of the strength was studied from the aspects of microstructure and vaporization of strengthening elements

  6. Welding technologies for nuclear machinery and equipment

    International Nuclear Information System (INIS)

    The main welding methods applied to nuclear machinery and equipment are shielded metal arc welding, submerged arc welding, MAG welding and TIG welding. But in the last 10 years, in order to improve the reliability required for the welding of nuclear machinery and equipment, the welding technologies aiming at the reduction of heat input, the decrease of the number of welding pass and the automatic control of welding factors have been applied for the main purpose of bettering the quality and excluding human errors. The merits and the technology of narrow gap, pulsed MAG welding and melt-through welding are explained. As the automation of TIG welding, image processing type narrow gap, hot wire TIG welding and remote control type automatic TIG welding are described. For the longitudinal welding of active metal sheet products, plasma key-hole welding is applied. Since the concentration of its arc is good, high speed welding with low heat input can be done. For the stainless steel cladding by welding, electroslag welding has become to be employed in place of conventional submerged arc welding. Arc is not generated in the electroslag welding, and the penetration into base metal is small. (K.I.)

  7. Development of multifunction laser welding head (1). Evaluation of under water laser welding with multifunction laser welding head

    International Nuclear Information System (INIS)

    Multifunction laser welding head has been developed. The head is able to perform not only underwater laser welding as repair, but also laser peening as preventive maintenance and laser ultrasonic testing as inspection. Laser transmission test with multifunction laser welding head and optical fiber was carried out. The result showed that laser power needed for welding was transmitted without any damage to them. Under water laser welding onto EDM slits with this welding head was carried out. EDM slits were sealed by deposited weld metal. It was confirmed that multifunction laser welding head was applied to under water laser welding. (author)

  8. New welding technologies for car body frame welding

    Directory of Open Access Journals (Sweden)

    T. Węgrzyn

    2012-12-01

    Full Text Available Purpose: of that paper was analysing main welding process for car body welding. The main reason of it was investigate possibilities of getting varied amount of acicular ferrite (AF in WMD (weld metal deposit. High amount of acicular ferrite influences positively impact toughness of weld. For optimal amount of AF it is necessary to have optimal chemical composition in WMD. Important role plays especially Ni. There were also tested new welding technology: welding with micro-jet cooling.Design/methodology/approach: During research with varied micro-jet parameters the chemical analysis, micrograph tests and Charpy V impact test of the metal weld deposit on pendulum machine were carried out. The Charpy V impact test was prepared according to standard ISO EN 148-1 Metallic materials - Charpy pendulum impact test - Part 1: Test method. Samples for impact testing were prepared according to standard ASTM A370.Findings: Varied amount of acicular ferrite in weld metal deposit (in range 55-75% in terms of microjet cooling parameters (numbers of jet, gas pressure. This high amount of acicular ferrite is unheard in weld metal deposit in another way or other methods of welding like MAG or TIG.Research limitations/implications: That research was made for MIG method (according to PN-EN ISO 4063:2009 only. Another method of welding in this article was not tested. Other methods (for eg. MAG, TIG have not been tested, but it is suspected that similar phenomena are taking place.Originality/value: In this research new method of cooling weld joint during welding was used. At the present time use of micro-jet cooling while MIG is in the testing phase and requires an accurate diagnosis.This method is very promising and capable of industrial application, mainly due to the significant improvement of weld quality and reduces costs.

  9. New Advances in Cytometric Instrumentation

    OpenAIRE

    Lopez, Peter

    2013-01-01

    The growing field of flow cytometry industry continues to produce exciting and innovative developments. Although the CyTOF mass spectrometry flow cytometer is one of the most revolutionary new developments (to be presented in another session), other advances have built upon the original FACS technology. The trends in cytometric instrumentation include smaller, easier to use analyzers and cell sorters, instrumentation capable of detecting multiple fluorescent colors even if their spectra overl...

  10. Fundamental Laser Welding Process Investigations

    DEFF Research Database (Denmark)

    Bagger, Claus; Olsen, Flemming Ove

    1998-01-01

    In a number of systematic laboratory investigations the fundamental behavior of the laser welding process was analyzed by the use of normal video (30 Hz), high speed video (100 and 400 Hz) and photo diodes. Sensors were positioned to monitor the welding process from both the top side and the rear...... side of the specimen.Special attention has been given to the dynamic nature of the laser welding process, especially during unstable welding conditions. In one series of experiments, the stability of the process has been varied by changing the gap distance in lap welding. In another series...

  11. 红船精神在中国革命精神系统中的地位和作用%Position and Function of the Red Boat Spirit in China's Revolutionary Spirit System

    Institute of Scientific and Technical Information of China (English)

    钟昌斌

    2015-01-01

    红船精神是中国革命精神之源,在中国革命精神系统中具有独特的地位和作用。从构成上看,红船精神把马克思主义科学理论因子作为思想内核,为推动中国革命精神始终走在先进思想前列提供了前提条件;继承并纳入中华传统文化的优良成分,奠定了先进的中国革命精神系统的保障基础。从作用看,红船精神是流淌在中国共产党血管中的基本能量,在当今不断发展的中国革命精神研究中充分体现出其特点,为推进中国革命精神系统化研究做出了贡献。从结果看,红船精神在推动中国革命精神建设和中国革命发展中谱写了恢弘的篇章。%The “Red Boat Spirit”,the source of the spirit of the Chinese revolution,holds a unique position in China's revolutionary spirit system.In view of its constitution ,the “Red Boat Spirit”,with the scientific theory of Marxism as its ideological core,provided preconditions to secure the Chinese revolutionary spirit in an advanced state;it inherited and brought in fine ingredients of traditional Chinese culture,and laid a guarantee foundation for the advanced Chinese revolutionary spirit system.In view of its function,the Red Boat Spirit is the basic energy flowing in the blood vessels of the CPC,fully reflecting its characteristics in today's evolving re-search of the Chinese revolution spirit,and contributing to the research of Chinese revolutionary spirit system. Concerning the consequence, the Red Boat Spirit has composed a grand chapter in promoting China's revolutionary spirit construction and the development of Chinese revolution.

  12. The Effect of Welding Speed on the Microstructure and Penetration in Arc Welding

    OpenAIRE

    DURGUTLU, Ahmet; GÜLENÇ, Behçet

    1999-01-01

    The effect of welding speed on the microstructure and penetration in MAG, SMAW and MMA welding was investigated in a low carbon steel. Experimental results revealed that the penetration decreased when the welding speed was lower or higher than the optimum speed. It was also observed that when the welding speed was high, undercuttings occurred at the edge of welding bead and microstructure of weld metals consisted of fine grains, but when the welding speed was low, at the edge of weld...

  13. Ultrasonic inspection of austenitic welds

    International Nuclear Information System (INIS)

    The metallurgical structure of austenitic welds is described and contrasted with that found in ferritic welds. It is shown that this structure imparts a marked elastic anisotropy in the ultrasonic propagation parameters. Measurements of variations in the apparent attenuation of sound and deviations in the beam direction are described. The measurements are interpreted in terms of the measured velocity anisotropy. Two applications of the fundamental work are described. In the first it is shown how, by using short pulse compression wave probes, and with major modification of the welding procedure, a stainless steel fillet weld in an AGR boiler can be inspected. In the second application, alternative designs of a transition butt weld have been compared for ease of ultrasonic inspection. The effects of two different welding processes on such an inspection are described. Finally, the paper examines the prospects for future development of inspection and defect-sizing techniques for austenitic welds. (author)

  14. End plug welding of nuclear fuel elements-AFFF experience

    International Nuclear Information System (INIS)

    Advanced Fuel Fabrication Facility is engaged in the fabrication of mixed oxide (U,Pu)O2 fuel elements of various types of nuclear reactors. Fabrication of fuel elements involves pellet fabrication, stack making, stack loading and end plug welding. The requirement of helium bonding gas inside the fuel elements necessitates the top end plug welding to be carried out with helium as the shielding gas. The severity of the service conditions inside a nuclear reactor imposes strict quality control criteria, which demands for almost defect free welds. The top end plug welding being the last process step in fuel element fabrication, any rejection at this stage would lead to loss of effort prior to this step. Moreover, the job becomes all the more difficult with mixed oxide (MOX) as the entire fabrication work has to be carried out in glove box trains. In the case of weld rejection, accepted pellets are salvaged by cutting the clad tube. This is a difficult task and recovery of pellets is low (requiring scrap recovery operation) and also leads to active metallic waste generation. This paper discusses the experience gained at AFFF, in the past 12 years in the area of end plug welding for different types of MOX fuel elements

  15. Welding technology transfer task/laser based weld joint tracking system for compressor girth welds

    Science.gov (United States)

    Looney, Alan

    1991-01-01

    Sensors to control and monitor welding operations are currently being developed at Marshall Space Flight Center. The laser based weld bead profiler/torch rotation sensor was modified to provide a weld joint tracking system for compressor girth welds. The tracking system features a precision laser based vision sensor, automated two-axis machine motion, and an industrial PC controller. The system benefits are elimination of weld repairs caused by joint tracking errors which reduces manufacturing costs and increases production output, simplification of tooling, and free costly manufacturing floor space.

  16. ICT diagnostic method of beryllium welding quality

    International Nuclear Information System (INIS)

    To avoid the interference of high density material for the quality assay of beryllium welding line, a slice by slice scanning method was proposed based upon the research results of the Industrial Computerized Tomography (ICT) diagnostics for weld penetration, weld width, off-centered deviation and weld defects of beryllium-ring welding seam with high density material inside

  17. Portable machine welding head automatically controls arc

    Science.gov (United States)

    Oleksiak, C. E.; Robb, M. A.

    1967-01-01

    Portable weld tool makes weld repairs out-of-station and on the side opposite the original weld. It provides full automatic control of the arc voltage, current, wire feed, and electrode travel speed in all welding attitudes. The device is readily adaptable to commercially available straight polarity dc weld packs.

  18. Welding Development: Marshall Space Flight Center

    Science.gov (United States)

    Ding, Jeff

    2007-01-01

    This paper presents the basic understanding of the friction stir welding process. It covers process description, pin tool operation and materials, metal flow theory, mechanical properties, and materials welded using the process. It also discusses the thermal stir welding process and the differences between thermal stir and friction stir welding. MSFC weld tools used for development are also presented.

  19. Sensor integration for robotic laser welding processes

    NARCIS (Netherlands)

    Iakovou, Dimitrios; Aarts, Ronald; Meijer, Johan

    2005-01-01

    The use of robotic laser welding is increasing among industrial applications, because of its ability to weld objects in three dimensions. Robotic laser welding involves three sub-processes: seam detection and tracking, welding process control, and weld seam inspection. Usually, for each sub-process,

  20. Deconvoluting the Friction Stir Weld Process for Optimizing Welds

    Science.gov (United States)

    Schneider, Judy; Nunes, Arthur C.

    2008-01-01

    In the friction stir welding process, the rotating surfaces of the pin and shoulder contact the weld metal and force a rotational flow within the weld metal. Heat, generated by the metal deformation as well as frictional slippage with the contact surface, softens the metal and makes it easier to deform. As in any thermo-mechanical processing of metal, the flow conditions are critical to the quality of the weld. For example, extrusion of metal from under the shoulder of an excessively hot weld may relax local pressure and result in wormhole defects. The trace of the weld joint in the wake of the weld may vary geometrically depending upon the flow streamlines around the tool with some geometry more vulnerable to loss of strength from joint contamination than others. The material flow path around the tool cannot be seen in real time during the weld. By using analytical "tools" based upon the principles of mathematics and physics, a weld model can be created to compute features that can be observed. By comparing the computed observations with actual data, the weld model can be validated or adjusted to get better agreement. Inputs to the model to predict weld structures and properties include: hot working properties ofthe metal, pin tool geometry, travel rate, rotation and plunge force. Since metals record their prior hot working history, the hot working conditions imparted during FSW can be quantified by interpreting the final microstructure. Variations in texture and grain size result from variations in the strain accommodated at a given strain rate and temperature. Microstructural data from a variety of FSWs has been correlated with prior marker studies to contribute to our understanding of the FSW process. Once this stage is reached, the weld modeling process can save significant development costs by reducing costly trial-and-error approaches to obtaining quality welds.

  1. Welding in nuclear engineering

    International Nuclear Information System (INIS)

    The 3rd international conference 'Welding in nuclear engineering', organized in 1978 by the Deutscher Verband fuer Schweisstechnik e.V., was, like the two foregoing conferences in 1970 and 1974, an absolute success. The noteworthy echo to this meeting in the international technical world - the number of 650 participants from 26 countries is self-evidence - and this fact, was for the Deutscher Verband fuer Schweisstechnik e.V. occasion and at the same time an obligation now to follow in the same way, the meeting that was started 12 years ago, by organizing the international conference 'Welding in nuclear engineering'. The conference this year offers in addition to the two plenary session lectures, 34 short reports and a further 28 single contributions in the form of two poster-sessions. Unfortunately, it was again not possible to accept all the papers submitted because the conference was limited to 2 days only. Nevertheless, the papers will offer a representative cross-section through the total range of welding engineering. In particular, the poster session, which take place for the first time within the scope of a meeting organized by the Working Group 'Welding in Nuclear Engineering', should contribute to the aim that this time again the discussions will form the main point of the conference. (orig./RW)

  2. Welding. Student Learning Guide.

    Science.gov (United States)

    Palm Beach County Board of Public Instruction, West Palm Beach, FL.

    This student learning guide contains 30 modules for completing a course in welding. It is designed especially for use in secondary schools in Palm Beach County, Florida. Each module covers one task, and consists of a purpose, performance objective, enabling objectives, learning activities keyed to resources, information sheets, student self-check…

  3. Thermal Stresses in Welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær

    1998-01-01

    Studies of the transient temperature fields and the hereby induced deformations and stressses in a butt-welded mild steel plate modelledrespectively in 2D plane stress state (as well as plane strain state) and in full 3D have been done. The model has been implemented in the generalpurpose FE...

  4. Microstructure of welded and weld-simulated modified 9Cr-1Mo (P 91) ferritic steel

    International Nuclear Information System (INIS)

    Within the last 30 years significant advances in materials development have been made which have enhanced the operation temperature of thermal power plants led to an improvement in efficiency. Currently, a great deal of work relating to the modified 9% Cr-1/5 Mo steel (P 91) is in progress. This type of steel was originally considered to be an appropriate candidate for Fast Breeder Applications, and it was designed by Oak Ridge National Laboratory. Up to the present, several modifications of 9% chromium steels have been developed in several labs all over the globe containing different portions of tungsten and molybdenum. This report focuses on the microstructural characterization of a heavy section multi pass weld done on a tube composed of P 91 steel. Weld simulations, using the Gleeble 1500 technology, were successfully applied to aid the microstructural study of the heat affected zone (HAZ). As revealed by the investigations, post weld heat treatment (PWHT) results in a softening of the heat affected zone in an area close to the uninfluenced base metal. According to the observed microstructure and Gleeble simulations, the peak temperature of the soft zone during welding falls within a temperature range between AC1 (= 810 C) and slightly above AC3 typically 900--930 C which was discovered for the first time in a previous investigation

  5. Microstructure of welded and weld-simulated modified 9Cr-1Mo (P 91) ferritic steel

    Energy Technology Data Exchange (ETDEWEB)

    Prader, R.; Cerjak, H. [Graz Univ. of Technology (Austria); David, S.A. [Oak Ridge National Lab., TN (United States)

    1996-12-31

    Within the last 30 years significant advances in materials development have been made which have enhanced the operation temperature of thermal power plants led to an improvement in efficiency. Currently, a great deal of work relating to the modified 9% Cr-1/5 Mo steel (P 91) is in progress. This type of steel was originally considered to be an appropriate candidate for Fast Breeder Applications, and it was designed by Oak Ridge National Laboratory. Up to the present, several modifications of 9% chromium steels have been developed in several labs all over the globe containing different portions of tungsten and molybdenum. This report focuses on the microstructural characterization of a heavy section multi pass weld done on a tube composed of P 91 steel. Weld simulations, using the Gleeble 1500 technology, were successfully applied to aid the microstructural study of the heat affected zone (HAZ). As revealed by the investigations, post weld heat treatment (PWHT) results in a softening of the heat affected zone in an area close to the uninfluenced base metal. According to the observed microstructure and Gleeble simulations, the peak temperature of the soft zone during welding falls within a temperature range between A{sub C1} (= 810 C) and slightly above A{sub C3} typically 900--930 C which was discovered for the first time in a previous investigation.

  6. Flaw evaluation of Nd:YAG laser welding based plume shape by infrared thermal camera

    International Nuclear Information System (INIS)

    In Nd:YAG laser welding evaluation methods of welding flaw are various. But, the method due to plume shape is difficult to classification od welding flaw. The Nd:YAG laser process is known to have high speed and deep penetration capability to become one of the most advanced welding technologies. At the present time, some methods are studied for measurement of plume shape by using high-speed camera and photo diode. This paper describes the machining characteristics of SM45C carbon steel welding by use of an Nd:YAG laser. In spite of its good mechanical characteristics, SM45C carbon steel has a high carbon contents and suffers a limitation in the industrial application due to the poor welding properties. In this study, plume shape was measured by infrared thermal camera that is non-contact/non-destructive thermal measurement equipment through change of laser generating power, speed, focus. Weld was performed on bead-on method. Measurement results are compared as two equipment. Here, two results are composed of measurement results of plume quantities due to plume shape by infrared thermal camera and inspection results of weld bead include weld flaws by ultrasonic inspector.

  7. Qualification Test of End Closure Welding for SFR Metallic Fuel Rod

    International Nuclear Information System (INIS)

    The six systems selected for Gen-IV promising systems and expected to be deployed in 2020. In Korea, the R and D on a sodium-cooled fast reactor (SFR) has been begun since 1997, as one of the national long-term nuclear R and D programs. As a fuel for SFR, metallic fuel, U-Zr alloy fuel, was selected and is being developed. And also the international collaborative research is under way on U-TRU-Zr fuel developments with the closed fuel cycle of full actinide recycling, within Advanced Fuel Project for international generation IV (Gen-IV) SFR. For the fabrication of SFR metallic fuel rods, the end plug welding is a crucial process. The sealing of end plug to cladding tube should be hermetically perfect to prevent a leakage of fission gases and to maintain a good reactor performance. In this study, the qualification test of the end closure welding for SFR metallic fuel rods was carried out based on the developed welding technique, welding equipment, welding conditions and parameters. Through the qualification test, the weld quality of end closure welding of SFR metallic fuel rod was evaluated according to the qualification test plan and satisfied the requirements on the weld. Consequently the qualified welding process is ready to produce SFR metallic fuel rods

  8. Numerical study of the mechanism of explosive/impact welding using Smoothed Particle Hydrodynamics method

    International Nuclear Information System (INIS)

    Highlights: ► SPH method was used in the simulation of explosive welding. ► The phenomenon of jetting and the interfacial waves were reproduced. ► The historical variations of shear stress, effective plastic strain were shown. ► Bonding is more likely to be a solid state welding process. -- Abstract: Metallic explosive welding is a very useful advanced high tech for metals welding and composite production. However, at present, a comprehensive theory which can give an accurate description and prediction of the parameters of explosive welding does not exist. Some investigators considered the welding as a solid state welding process, but others believed that the process is a fusion welding process. The objective of this work is to investigate which theory is more reasonable, in particular to improve understanding of the factors that determine the quality of explosive welded bonds and try to relate the effect of the process variables on the physical parameters. The finite difference engineering package AUTODYN with Smoothed Particle Hydrodynamics (SPH) method has been used in this work, and the phenomenon of jetting and the interfacial waves observed in explosive welding were quite well reproduced in these simulations. The historical changes of shear stress, effective plastic strain of materials were clearly shown in the simulation. It is found that bonding is more likely to be a solid state welding process, however, in some cases, it is likely to be a fusion welding process. The effective plastic strains were greater than the threshold value and the shear stresses were of opposite sign in the simulations of cases where good bonding occurred.

  9. Consideration of weld behaviour in design of high-temperature components

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, M. [IMWF, Univ. Stuttgart (Germany); Maile, K.; Klenk, A.; Roos, E. [MPA, Univ. Stuttgart (Germany)

    2007-07-01

    Fully loaded seams in pressurized components operating in the creep range, require different strategies in design and monitoring. This is due to the particular failure behavior in the HAZ under creep loading which leads - for a number of materials discussed in this paper - to premature fracture in the HAZ. Until the verification, that an additional heat treatment (quench and temper) post welding compensates this particular failure behavior, special measures have to be taken, in order to guarantee a safe operation. These measures primarily consist in the determination of material specific, time and temperature dependent weld strength factors instead of standard reduction factors. Those factors are not included in the established standards and have to be determined experimentally - similarly to the design parameters of the base material. Due to the high risk potential in case of failure of fully loaded components, the monitoring has to be optimized based on additional instrumentation and inelastic numeric analyses to determine the state of damage of a component. Recommendations for finite-element-analysis of welded components in the creep range are given, including advanced constitutive equations and recommendations for modeling of welded components. Furthermore, the necessary steps for consideration of weld behavior in order to be used in modern design procedures are described, such as the understanding of the failure mechanism of welded joints under long term creep loading and the transferability of weld creep strength and weld creep strength factors on components. Specific behavior of similar and dissimilar welds in the creep regime are described besides procedures and criteria to be used for the assessment of welded joints. Here several examples i. e. thin walled, pressurized pipes with circumferential and longitudinal weld respectively as well as thick walled pipes with longitudinal welds are discussed in detail. (orig.)

  10. Measuring revolutionary biomedical science 1992-2006 using Nobel prizes, Lasker (clinical medicine) awards and Gairdner awards (NLG metric).

    Science.gov (United States)

    Charlton, Bruce G

    2007-01-01

    The Nobel prize for medicine or physiology, the Lasker award for clinical medicine, and the Gairdner international award are given to individuals for their role in developing theories, technologies and discoveries which have changed the direction of biomedical science. These distinctions have been used to develop an NLG metric to measure research performance and trends in 'revolutionary' biomedical science with the aim of identifying the premier revolutionary science research institutions and nations from 1992-2006. I have previously argued that the number of Nobel laureates in the biomedical field should be expanded to about nine per year and the NLG metric attempts to predict the possible results of such an expansion. One hundred and nineteen NLG prizes and awards were made during the past fifteen years (about eight per year) when overlapping awards had been removed. Eighty-five were won by the USA, revealing a massive domination in revolutionary biomedical science by this nation; the UK was second with sixteen awards; Canada had five, Australia four and Germany three. The USA had twelve elite centres of revolutionary biomedical science, with University of Washington at Seattle and MIT in first position with six awards and prizes each; Rockefeller University and Caltech were jointly second placed with five. Surprisingly, Harvard University--which many people rank as the premier world research centre--failed to reach the threshold of three prizes and awards, and was not included in the elite list. The University of Oxford, UK, was the only institution outside of the USA which featured as a significant centre of revolutionary biomedical science. Long-term success at the highest level of revolutionary biomedical science (and probably other sciences) probably requires a sufficiently large number of individually-successful large institutions in open competition with one another--as in the USA. If this model cannot be replicated within smaller nations, then it implies

  11. Improvements in and relating to welding

    International Nuclear Information System (INIS)

    This invention concerns apparatus for use in welding, particularly welding which must be effected in a predetermined, for example, inert atmosphere, e.g. the welding of reactive materials such as zircaloy, titanium, magnesium, aluminium, etc. (U.K.)

  12. Horizontal electron beam welding for stainless steels

    International Nuclear Information System (INIS)

    Stainless steel samples have been realized by local vacuum apparatus for electron beam welding applications to reactor core shell realizations. The best welding parameters have been determined by a systematic study. The welds have been characterized by mechanical tests

  13. «FREEDOM OF CONSCIENCE» AND «RELIGIOUS FREEDOM» IN THE UNDERSTANDING OF PRE-REVOLUTIONARY SCIENTISTS

    OpenAIRE

    Nadezhda Yuryevna Zagaynova

    2015-01-01

    The article considers approaches to the understanding of the concepts of «freedom of conscience» and «religious freedom» on the basis of the analysis of works of pre-revolutionary scientists. Allocated General and special traits defining these phenomena.The aim of this article is (based on the works of pre-revolutionary scientists) to analyze ideas about the concept of freedom of conscience and religious liberty. Previously, scientists no attempt has been made to summarize the theoretical asp...

  14. Fundamental Difficulties Associated With Underwater Wet Welding

    OpenAIRE

    Joshua E. Omajene,; Jukka Martikainen

    2014-01-01

    The offshore industries carry out welding activities in the wet environment. It is evident that the wet environments possess difficulties in carrying out underwater welding. Therefore there is the need to improve the quality of weld achieved in underwater welding. This paper investigates the difficulties associated with underwater welding. The objective of this research paper is to identify and analyze the different difficulties in underwater welding so as to make a clear back...

  15. Design and realization of a welding oscillator

    OpenAIRE

    Özcan, Muciz

    2014-01-01

    Welding is one of the most popular methods to combine metal pieces in manufacturing processes. Arc welding, among all welding techniques, is the most commonly used in manufacturing due to its cost and flexibility. During the manufacturing process, arc welding is either performed by an operator or by automatic tools such as welding oscillators. Using automatic tools has advantages over manual use, as the process will be faster, cheaper, and have less welding flaws. In this paper, a homem...

  16. Industrial laser welding evaluation study

    Science.gov (United States)

    Hella, R.; Locke, E.; Ream, S.

    1974-01-01

    High power laser welding was evaluated for fabricating space vehicle boosters. This evaluation was made for 1/4 in. and 1/2 in. aluminum (2219) and 1/4 in. and 1/2 in. D6AC steel. The Avco HPL 10 kW industrial laser was used to perform the evaluation. The objective has been achieved through the completion of the following technical tasks: (1) parameter study to optimize welding and material parameters; (2) preparation of welded panels for MSFC evaluation; and (3) demonstration of the repeatability of laser welding equipment. In addition, the design concept for a laser welding system capable of welding large space vehicle boosters has been developed.

  17. Models of plasma arc welding

    International Nuclear Information System (INIS)

    A complex model of energy transfer from ionized gas through a weld-pool to a heat affected zone (HAZ) is considered here. The model consists of three sub-models: a model of the arc column with skin layers - sheaths coating electrodes, a model of liquid metal flow in a weld-pool, and a model of coupled thermo-mechanical-metallurgical processes in HAZ. These sub-models are descried in three reports. The first report is devoted to a short review of welding plasma models based mostly on the Magneto-Hydro-Dynamics (MHD) theory successfully applied to the simulation of welding process. This report is illustrated by arc models for TIG and PAW welding. The description of thermal energy transfer between three sub-regions of the complex welding domain refers to a large number of processes observed in gaseous electronics, thermodynamics of reacting gases, electro-dynamics of fluid, micro-metallurgy. (author)

  18. Corrosion of carbon steel welds

    International Nuclear Information System (INIS)

    This report assesses the factors which cause preferential attack to occur in carbon steel fusion welds. It was concluded that the main factors were: the inclusion content of the weld metal, the potential of the weld metal being less noble than that of the parent, and the presence of low-temperature transformation products in the heat-affected zone of the weld. These factors should be minimized or eliminated as appropriate so that the corrosion allowances determined for carbon steel waste drums is also adequate for the welds. An experimental/theoretical approach is recommended to evaluate the relative corrosion resistance of welds prepared from BS 4360 grade 43A steel to that of the parent material. (author)

  19. Overlay welding irradiated stainless steel

    International Nuclear Information System (INIS)

    An overlay technique developed for welding irradiated stainless steel may be important for repair or modification of fusion reactor materials. Helium, present due to n,α reactions, is known to cause cracking using conventional welding methods. Stainless steel impregnated with 3 to 220 appm helium by decay of tritium was used to develop a welding process that could be used for repair. The result was a gas metal arc weld overlay technique with low-heat input and low-penetration into the helium-containing material. Extensive metallurgical and mechanical testing of this technique demonstrated substantial reduction of helium embrittlement damage. The overlay technique was applied to irradiated 304 stainless steel containing 10 appm helium. Surface cracking, present in conventional welds made on the same steel at lower helium concentrations, was eliminated. Underbead cracking, although greater than for tritium charged and aged material, was minimal compared to conventional welding methods

  20. Irradiation stability of welded joints

    International Nuclear Information System (INIS)

    Results are presented of investigations into the neutron irradiation stability of welded joints in two types of steel used for reactor pressure vessels. Details are given of the materials used, method of welding and tests applied. The effect of irradiation on the notch toughness transition curve is shown. The results of the studies into irradiation embrittlement of all the welded joints and parent materials of the steels for the pressure vessels are summarized. (U.K.)

  1. Residual stresses in welded structures

    International Nuclear Information System (INIS)

    The nature of residual stresses in welded structures is discussed in terms of their magnitude, directionality, spatial distribution, range and variability. The effects of the following factors on the residual stresses are considered: material properties, material manufacture, structural geometry, fabrication procedure, welding procedure, post-weld treatments and service conditions. Examples are given of residual stress distributions in plate butt welds, circumferential butt welds and weld cladding. These illustrate the different magnitudes and distributions of residual stress that can be found in different joint geometries, and demonstrate the effects of the mechanical, thermal and metallurgical properties of the constituent materials and the sensitivity of residual stresses to pass sequence and to the restraints applied during welding. Further examples for the common case of circumferential butt welds in pipes and pressure vessels are used to illustrate the extent of residual stresses as a function of distance from the weld and the effects of post-weld heat treatment. Measurements or analytical predictions of residual stresses are often subject to significant scatter or variability. This scatter may be due to systematic factors such as variability in measurement location or material properties, or to experimental error in measured data, erroneous assumptions in analytical modelling or unknown factors such as pre-existing residual stresses, inadequately documented welding or fabrication procedures or unrecorded local repairs. Improved prediction and reduction of uncertainty of residual stresses will require better recording of the whole manufacturing and service history of the welded structure and its component materials and better understanding and analysis of the many processes that may affect the residual stresses

  2. Pulsed ultrasonic stir welding system

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

    An ultrasonic stir welding system includes a welding head assembly having a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. During a welding operation, ultrasonic pulses are applied to the rod as it rotates about its longitudinal axis. The ultrasonic pulses are applied in such a way that they propagate parallel to the longitudinal axis of the rod.

  3. Collection of arc welding process data

    Directory of Open Access Journals (Sweden)

    K. Luksa

    2006-04-01

    Full Text Available Purpose: The aim of the research was to examine the possibility of detecting welding imperfections by recording the instant values of welding parameters. The microprocessor controlled system for real-time collection and display of welding parameters was designed, implemented and tested.Design/methodology/approach: The system records up to 4 digital or analog signals collected from welding process and displays their run on the LCD display. To disturb the welding process artificial disturbances were introduced.Findings: The occurrence of some welding imperfections is followed by changes of the welding parameters. In this case they can be revealed by the analysis of the instant values of the welding parameters.Research limitations/implications: In the paper results of monitoring manual metal arc welding and gas metal arc welding are presented.Practical implications: Monitoring of gas metal arc welding is a good tool for evaluation of the quality of weld. All introduced, artificial disturbances of the welding process destabilize the welding arc and produce changes in the instant values of the welding parameters.Originality/value: The paper presents a modern microprocessor controlled system for real-time collection and display of welding parameters. Results of tests show that simple statistical approach to welding parameters can help in evaluation of weld quality.

  4. Fuel rod welding (LWBR development program)

    International Nuclear Information System (INIS)

    Procedures were developed to weld both ends of approximately 25,000 fuel rods for the Light Water Breeder Reactor (LWBR) core. The rods were welded using the gas tungsten arc (GTA) method in high-purity helium at 1 atmosphere. Welding parameters, including weld current, arc gap, and speed of rotation, were established to control the size of the weld. Electrode and chill positioning with respect to the endclosure/tube joint controlled the location of the weld. Weld quality of the fuel rods was ensured by 100-percent nondestructive testing by ultrasonic and radiographic inspection and the destructive evaluation of process control samples in each weld lot

  5. Welding zircaloy thin tubes to end plugs

    International Nuclear Information System (INIS)

    This work aimed at optimizing parameters while welding zircaloy-2 tubes with end plugs, as a simulation of a part of the fabrication of the nuclear fuel pins. Samples were welded by tungsten-inert gas-arc welding (TIC) process under controlled atmosphere of pure argon. Some samples were welded using electron beam (EB) welding process. For samples welded using TIC process both the design of the welding chamber (size and tightness) , and the purity of the shielding atmosphere were found to have appreciable effect on the quality of the welded joint. Increasing the are length and/or the welding current increases grain growth and extends both fusion and heat-affected zones. However, heat input (are length and welding current) must be high enough to give complete penetration welds. Optimum are length of 1.2 mm was found to give good welds with the smallest possible heat affected and fusion zones. Optimum parameters of EB welding process (vacuum, welding current and EB amplitude) were determined. welds prepared by EB welding were found to have finer grain size and less extended fusion and heat-affected zones. Welds prepared by both TIC and EB processes were inspected visually, metallo graphically and by using X-ray radiography. Welds integrity were tested using helium leak and pressure tests. 7 figs

  6. Quantitative characterization of porosity in laser welds of stainless steel

    International Nuclear Information System (INIS)

    Standing-edge joints made by a continuous-wave Nd:YAG laser are examined in 304L stainless steel to advance understanding of the linkage between processing and microstructure in high-rate solidification events. Microcomputed tomography combined with traditional metallography has provided qualitative and quantitative characterization of welds in this material system of broad use and applicability. Pore presence and variability have been examined three-dimensionally for average values, spatial distributions and morphology, and related to processing parameters such as weld speed, delivered power and focal lens.

  7. Properties and Microstructural changes in T24 Weld Metal in 0.5Cr/2.5Cr/9Cr Dissimilar Welds During Annealing

    Czech Academy of Sciences Publication Activity Database

    Výrostková, A.; Jedináková, M.; Kroupa, Aleš

    Bratislava : Výskumný ústav zváračský, 2004, 4 KB. [Advanced Metallic Materials and Their Joining. Bratislava (SK), 25.10.2004-27.10.2004] R&D Projects: GA ČR GA106/03/1354 Institutional research plan: CEZ:AV0Z2041904 Keywords : welding * modelling of weld * microstructure Subject RIV: BM - Solid Matter Physics ; Magnetism

  8. The ethnic roots of class universalism: rethinking the "Russian" revolutionary elite.

    Science.gov (United States)

    Riga, Liliana

    2008-11-01

    This article retrieves the ethnic roots that underlie a universalist class ideology. Focusing empirically on the emergence of Bolshevism, it provides biographical analysis of the Russian Revolution's elite, finding that two-thirds were ethnic minorities from across the Russian Empire. After exploring class and ethnicity as intersectional experiences of varying significance to the Bolsheviks' revolutionary politics, this article suggests that socialism's class universalism found affinity with those seeking secularism in response to religious tensions, a universalist politics where ethnic violence and sectarianism were exclusionary, and an ethnically neutral and tolerant "imperial" imaginary where Russification and geopolitics were particularly threatening or imperial cultural frameworks predominated. The claim is made that socialism's class universalism was as much a product of ethnic particularism as it was constituted by it. PMID:19569395

  9. Experimental Investigation of the Corrosion Behavior of Friction Stir Welded AZ61A Magnesium Alloy Welds under Salt Spray Corrosion Test and Galvanic Corrosion Test Using Response Surface Methodology

    OpenAIRE

    Dhanapal, A.; Boopathy, S. Rajendra; Balasubramanian, V.; Chidambaram, K; Zaman, A. R. Thoheer

    2013-01-01

    Extruded Mg alloy plates of 6 mm thick of AZ61A grade were butt welded using advanced welding process and friction stir welding (FSW) processes. The specimens were exposed to salt spray conditions and immersion conditions to characterize their corrosion rates on the effect of pH value, chloride ion concentration, and corrosion time. In addition, an attempt was made to develop an empirical relationship to predict the corrosion rate of FSW welds in salt spray corrosion test and galvanic corrosi...

  10. Pulsed ultrasonic stir welding method

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

    A method of performing ultrasonic stir welding uses a welding head assembly to include a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. In the method, the rod is rotated about its longitudinal axis during a welding operation. During the welding operation, a series of on-off ultrasonic pulses are applied to the rod such that they propagate parallel to the rod's longitudinal axis. At least a pulse rate associated with the on-off ultrasonic pulses is controlled.

  11. Diffusion welding multifilament superconductive composites

    Energy Technology Data Exchange (ETDEWEB)

    Witherell, C.E.

    1978-02-27

    Diffusion welding is shown to be a feasible method for joining composites of niobium-titanium superconductor alloy filaments in a pure copper matrix. Good results were repeatedly obtained using 15/sup 0/ scarf joints welded with externally heated tooling and simple uniaxial compression loading in a conventional hydraulic press. Weld cycles of less than one hour total elapsed time were readily attainable. Through proper closed-die design, it was possible to increase welding pressure sufficiently to use relatively low temperatures to coincide with the optimum aging heat treatment of the superconductor alloy. This temperature limitation is important to retain optimal superconductor properties. Confirming measurements of critical current density of welded joints at 4.2/sup 0/K are in progress. In the welded joints made under optimum conditions, there is bonding of all constituents, including superconductor filaments. Weld tooling which effectively contains the relatively fluid matrix, and resists deformation during repeated weld cycles, is essential to the successful application of the diffusion welding process to these composites.

  12. Weld process study for 316L stainless steel weld metal for liquid helium service

    International Nuclear Information System (INIS)

    This study was conducted to determine the effects of welding process choice on the cryogenic properties of 316L stainless steel welds. Six weldments were impact tested down to 77 K and tensile and fracture toughness tested down to 4 K. The best properties obtained were from a GTA weld, followed by GMA welds; SA welds had the poorest properties. This variation in properties was attributed to the cleanliness of the weld metal, which is dependent on the welding process and parameters selected

  13. Spot Welding Parameter Optimization to Improve Weld Characteristics for Dissimilar Metals

    OpenAIRE

    Aravinthan Arumugam; MohdAmizi Nor

    2015-01-01

    Abstract Resistance spot welding is a process which is widely used in the automotive industry to join steel parts of various thicknesses and types. The current practice in the automotive industry in determining the welding schedule which will be used in the welding process is based on welding table or experiences. This however may not be the optimum welding schedule that will give the best spot weld quality. This work concentrates on the parameter optimization when spot welding steels with di...

  14. Nondestructive testing of weldings

    International Nuclear Information System (INIS)

    Today the nondestructive testing of materials with transverse weldings would be often neglect. Because the production of this parts will get more expensive it is interesting to test the parts eg. cans with ultrasound. Within this research program we developed a testing device for automatically testing of materials with transverse weldings, e.g. tubes. Functional characteristics: after putting in the test tube in the testing device the transducer is adjusted automatically to the best adjustment. This takes place with three step motors. The mechanic of adjustments gets its information from an optimal computer. The optimal computer processes the signals, which it gets from the automatic evaluator during the adjustment and stores the optimal adjustment parameters. With an additional equipment on can identify the exact source of error, if the testing device turns out and the repairing of the part can take place very fast. With an appropiate mechanical science the devide is useable in a production line with high flow rate. (orig.)

  15. Welding of Prosthetic Alloys

    OpenAIRE

    Wojciechowska M.; Wołowiec E.; Klimek L.

    2015-01-01

    This paper presents the techniques of joining metal denture elements, used in prosthetic dentistry: the traditional soldering technique with a gas burner and a new technique of welding with a laser beam; the aim of the study was to make a comparative assessment of the quality of the joints in view of the possibility of applying them in prosthetic structures. Fractographic examinations were conducted along with tensile strength and impact strength tests, and the quality of the joints was asses...

  16. Steels and welding nuclear

    International Nuclear Information System (INIS)

    This ENEA Data-Base regards mechanical properties, chemical composition and heat treatments of nuclear pressure vessel materials: type A533-B, A302-B, A508 steel plates and forgings, submerged arc welds and HAZ before and after nuclear irradiation. Irradiation experiments were generally performed in high flux material test reactors. Data were collected from international available literature about water nuclear reactors pressure vessel materials embrittlement

  17. Formation mechanism for the nanoscale amorphous interface in pulse-welded Al/Fe bimetallic systems

    Science.gov (United States)

    Li, Jingjing; Yu, Qian; Zhang, Zijiao; Xu, Wei; Sun, Xin

    2016-05-01

    Pulse or impact welding traditionally has been referred to as "solid-state" welding. By integrating advanced interface characterizations and diffusion calculations, we report that the nanoscale amorphous interface in the pulse-welded Al/Fe bimetallic system is formed by rapid heating and melting of a thin Al layer at the interface, diffusion of iron atoms in the liquid aluminum, and subsequent rapid quenching with diffused iron atoms in solution. This finding challenges the commonly held belief regarding the solid-state nature of the impact-based welding process for dissimilar metals. Elongated ultra-fine grains with high dislocation density and ultra-fine equiaxed grains also are observed in the weld interface vicinity on the steel and aluminum sides, respectively, which further confirms that melting and the subsequent recrystallization occurred on the aluminum side of the interface.

  18. Welding technology in TF coil of international thermonuclear experimental reactor (ITER) project

    International Nuclear Information System (INIS)

    Japan Atomic Energy Agency is responsible for 9 TF coils and 19 TF coil structures as Japanese domestic agency in the ITER project. To apply the special environment, which is the high magnetic field and the cryogenic temperature of 4 K, high strength and high toughness are required for materials of the superconducting coil. Thus, fully austenite stainless steel is selected. Advanced welding technology is needed to control the crack sensitivity by welding and ensure high reliability of welding. To solve these issues, trials for the optimization of the chemical composition and the welding condition are conducted. As a result, high quality of welding for fully austenite stainless steel was successfully achieved. By applying this result, manufacturing of actual TF coils for the ITER was started. (author)

  19. Method of welding nuclear reactor fuel assemblies

    International Nuclear Information System (INIS)

    Disclosed is a method of welding tabs projecting outwardly from grip straps in a fuel assembly grid to a control rod guide thimble positioned in a cell in the grid including providing a weld guide having openings therein which receive dimples on the strap when the weld guide is placed in a cell adjacent to the cell containing the control rod guide thimble. The weld guide includes an opening which falls into alignment with a tab so that when a welding gun electrode is placed through the opening and into contact with a tab, the other electrode is automatically centered on its tab thus permitting accurate spot welding of the parts. To make a second spot weld on the same tab but at a point outwardly from the first spot weld, a second weld guide having an opening therein displaced a greater distance from a reference point on the weld guide, is placed in the same cell and the welding process repeated

  20. Welding of carbon steel vessels without post weld heat treatment

    International Nuclear Information System (INIS)

    The methods available for the repair welding of carbon steel vessels without post weld heat treatment and with particular reference to service in a sour environment have been reviewed. All the available techniques have the common aim of providing adequate properties in the weld metal and heat affected zone without the need for a full post weld stress relief. The heat that is required to provide the necessary metallurgical changes comes, therefore, from an alternate source. The two sources used are heat from suitably placed subsequent weld passes or from localized external heat sources. The technique presently being used by Ontario Hydro to repair vessels subject to sour service utilizes both a high preheat and a welding technique which is designed to temper the heat affected zone formed in the base material by the first weld pass. This technique is an improvement over the 'half bead' techniques given in the ASME X1 code and has been shown to be capable of reducing the hardness of the heat affected zone to an acceptable level. Certain recommendations have been made which could improve control of the technique presently used by Ontario Hydro and provide measurable parameters between procedural tests and the actual weld repairs

  1. Comparison Between Keyhole Weld Model and Laser Welding Experiments

    Energy Technology Data Exchange (ETDEWEB)

    Wood, B C; Palmer, T A; Elmer, J W

    2002-09-23

    A series of laser welds were performed using a high-power diode-pumped continuous-wave Nd:YAG laser welder. In a previous study, the experimental results of those welds were examined, and the effects that changes in incident power and various welding parameters had on weld geometry were investigated. In this report, the fusion zones of the laser welds are compared with those predicted from a laser keyhole weld simulation model for stainless steels (304L and 21-6-9), vanadium, and tantalum. The calculated keyhole depths for the vanadium and 304L stainless steel samples fit the experimental data to within acceptable error, demonstrating the predictive power of numerical simulation for welds in these two materials. Calculations for the tantalum and 21-6-9 stainless steel were a poorer match to the experimental values. Accuracy in materials properties proved extremely important in predicting weld behavior, as minor changes in certain properties had a significant effect on calculated keyhole depth. For each of the materials tested, the correlation between simulated and experimental keyhole depths deviated as the laser power was increased. Using the model as a simulation tool, we conclude that the optical absorptivity of the material is the most influential factor in determining the keyhole depth. Future work will be performed to further investigate these effects and to develop a better match between the model and the experimental results for 21-6-9 stainless steel and tantalum.

  2. Effect of sulfur on weld geometry in pulsed laser welds

    International Nuclear Information System (INIS)

    The primary goal of the present study was to determine whether compositional differences in a surface active element in austenitic stainless steel can alter the geometry of pulsed laser welds. Clearly, much less time is available during pulse laser welding for convection cells to form and influence heat transfer. A two-dimensional heat-transfer code has been developed for pulsed Nd:YAG laser welding that only incorporates heat transfer by conduction for the molten metal. For fluences that do not result in significant evaporation, this code generally yields good predictions of weld geometries, if appropriate corrections are made for surface absorptivity. At higher fluences, significant differences are found between predicted and observed weld pool shapes. This study is a portion of a larger program to determine the causes of these differences. Earlier work has produced direct experimental evidence that convection cells can develop during pulsed laser welding. However, experimental evidence that convection is present during welding is not sufficient to indicate whether convection is a dominant heat transfer mechanism. More recently, modeling of transient two-dimensional Marangoni flow in a pulsed laser weld pool was attempted

  3. Gas Metal Arc Welding. Welding Module 5. Instructor's Guide.

    Science.gov (United States)

    Missouri Univ., Columbia. Instructional Materials Lab.

    This guide is intended to assist vocational educators in teaching an eight-unit module in gas metal arc welding. The module is part of a welding curriculum that has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The following topics are covered in the module: safety and testing, gas metal arc…

  4. The treatment of surface oxide for reactor repair welding

    International Nuclear Information System (INIS)

    A description is presented of potential methods for the treatment of surface oxide in magnox reactors in preparation for repair welding. Advanced weld process fluxing techniques together with mechanical, thermal and chemical cleaning methods are examined in relation to their state of development and feasibility. It is considered that in the short term, mechanical cleaning methods are most likely to be applicable. Weld process fluxing is shown to be a viable technique where the oxide thickness is low, and could form the basis of a medium term development. Possible longer term developments include chemical and thermal cleaning techniques. Recommendations are made for a number of work areas with a view to developing a strategy applicable to the magnox repair programme. (author)

  5. Orbital welding technology speeds riser construction of offshore platforms

    Energy Technology Data Exchange (ETDEWEB)

    Henon, B.K. (Arc Machines, Inc., Pacoima, CA (United States))

    1994-05-01

    Strategically situated adjacent to the North Sea oil fields, Haugesund Mekaniske Versted (HMV) has become one of Norway's leading construction yards for the oil and gas-related industry. In keeping with its leadership role in offshore construction, HMV has just completed its first project using advanced orbital GTA welding technology. The project, which was begun in August 1992 and completed in January 1993, was the construction of risers for the Draugen platform, owned by Shell Oil, and the Statfjord platform, owned by Statoil. The risers are the piping that extends from the well head on the seabed up to the platform hull. This hull is supported above the water level by concrete towers. This paper discusses the welding equipment used and the weld procedure qualifications.

  6. Heat Control via Torque Control in Friction Stir Welding

    Science.gov (United States)

    Venable, Richard; Colligan, Kevin; Knapp, Alan

    2004-01-01

    In a proposed advance in friction stir welding, the torque exerted on the workpiece by the friction stir pin would be measured and controlled in an effort to measure and control the total heat input to the workpiece. The total heat input to the workpiece is an important parameter of any welding process (fusion or friction stir welding). In fusion welding, measurement and control of heat input is a difficult problem. However, in friction stir welding, the basic principle of operation affords the potential of a straightforward solution: Neglecting thermal losses through the pin and the spindle that supports it, the rate of heat input to the workpiece is the product of the torque and the speed of rotation of the friction stir weld pin and, hence, of the spindle. Therefore, if one acquires and suitably processes data on torque and rotation and controls the torque, the rotation, or both, one should be able to control the heat input into the workpiece. In conventional practice in friction stir welding, one uses feedback control of the spindle motor to maintain a constant speed of rotation. According to the proposal, one would not maintain a constant speed of rotation: Instead, one would use feedback control to maintain a constant torque and would measure the speed of rotation while allowing it to vary. The torque exerted on the workpiece would be estimated as the product of (1) the torque-multiplication ratio of the spindle belt and/or gear drive, (2) the force measured by a load cell mechanically coupled to the spindle motor, and (3) the moment arm of the load cell. Hence, the output of the load cell would be used as a feedback signal for controlling the torque (see figure).

  7. Optimization of Gas Metal Arc Welding (GMAW) Process for Maximum Ballistic Limit in MIL A46100 Steel Welded All-Metal Armor

    Science.gov (United States)

    Grujicic, M.; Ramaswami, S.; Snipes, J. S.; Yavari, R.; Yen, C.-F.; Cheeseman, B. A.

    2015-01-01

    Our recently developed multi-physics computational model for the conventional gas metal arc welding (GMAW) joining process has been upgraded with respect to its predictive capabilities regarding the process optimization for the attainment of maximum ballistic limit within the weld. The original model consists of six modules, each dedicated to handling a specific aspect of the GMAW process, i.e., (a) electro-dynamics of the welding gun; (b) radiation-/convection-controlled heat transfer from the electric arc to the workpiece and mass transfer from the filler metal consumable electrode to the weld; (c) prediction of the temporal evolution and the spatial distribution of thermal and mechanical fields within the weld region during the GMAW joining process; (d) the resulting temporal evolution and spatial distribution of the material microstructure throughout the weld region; (e) spatial distribution of the as-welded material mechanical properties; and (f) spatial distribution of the material ballistic limit. In the present work, the model is upgraded through the introduction of the seventh module in recognition of the fact that identification of the optimum GMAW process parameters relative to the attainment of the maximum ballistic limit within the weld region entails the use of advanced optimization and statistical sensitivity analysis methods and tools. The upgraded GMAW process model is next applied to the case of butt welding of MIL A46100 (a prototypical high-hardness armor-grade martensitic steel) workpieces using filler metal electrodes made of the same material. The predictions of the upgraded GMAW process model pertaining to the spatial distribution of the material microstructure and ballistic limit-controlling mechanical properties within the MIL A46100 butt weld are found to be consistent with general expectations and prior observations.

  8. Research on TIG weld machine of the upper side ring slot of Gd-rod technology reconstruct

    International Nuclear Information System (INIS)

    The research on TIG weld machine of the upper side ring slot of Gd-rod existent matter: seal electrical source got up difficulty; control system had graveness aging; space between was adjusted precision lowness; welding torch lay mode and structure were not in reason. carried through all around technology reconstruct: had chosen the best of TIG weld machine; designed ignite arc device, designed optics imaging device, designed tungsten mighty axis direction auto conditioning, was provided with arc slot, adopted PLC to control the whole system and realization auto control. After TIG weld machine of the upper side ring slot of Gd-rod technology reconstruct research , provided with arc slot the first time in the Gd-rod of nuclear fuel, optimized the weld technics, improved welding line melt width and deep equality, stability, and great breadth advanced nuclear fuel product line technology and throughput. (authors)

  9. Residual strains and microstructure development in single and sequential double sided friction stir welds in RQT-701 steel

    International Nuclear Information System (INIS)

    Single and double sided partial penetration friction stir butt welds, in a rolled, quenched and tempered steel (RQT-701), were produced at The Welding Institute (TWI) under controlled process conditions. The residual strain distributions in the longitudinal and transverse directions have been measured using energy dispersive synchrotron X-ray diffraction. The measured strains were indicative of longitudinal tensile residual stresses at levels greater than the 0.2% yield stress of the parent metal in both the single and double pass welds. In both cases, the maximum tensile strain was found in the parent metal at the boundary of the heat affected zone (HAZ). Microstructural analysis of the welds was carried out using optical microscopy and hardness variations were also mapped across the weld-plate cross-section. The maximum hardness was observed in the mixed bainite/martensite structure of the weld nugget on the advancing side of the stir zone. The minimum hardness was observed in the HAZ

  10. Orbital TIG (GTAW) welding for highest weld joint quality requirements

    International Nuclear Information System (INIS)

    Due to its many advantages orbital TIG (GTAW) welding has become the major standard for mechanised tube and pipe weldings in various industries such as: Semiconductor, food and beverage, dairy and brewery, chemical and bio-/pharmaceutical industry, vessel construction, aerospace, offshore and shipbuilding, heat-exchanger, fossil and nuclear power generation. Today's state-of-the-art technology allows orbital weldings of tubes, pipes, fittings or similar parts from 2,3 mm O.D. up to unlimited sizes (including flat plate). Wall thicknesses from 0,3 mm to 175 mm (narrow groove) can easily be accommodated. For difficult applications like inbore weldings, valve seat repairs or video-controlled remote welds, special equipment can be provided or individually manufactured on customer's demand. (orig.)

  11. Effect Of Process Parameters On Mechanical Properties Of Friction Stir.Welded Joint Of Two Similar &Dissimilar Al-Alloys

    Directory of Open Access Journals (Sweden)

    Umasankar Das,

    2015-09-01

    Full Text Available Friction Stir Welding (FSW is an advance joining process for different similar and dissimilar materials. It is commonly used for joining of Aluminum alloys. However it is necessary to overcome some challenges for its wide-spread uses. Tool design and the selection of process parameters are critical issues in the usage of this process. This study focuses on the process parameters that is required for producing effective friction stir welding of two similar aluminum alloys (AA6101T6 to AA6101T6 and dissimilar Aluminum alloys (AA6101T6 alloy to AA6351T6 . Three different tool diameters such as 20 mm, 25 mm and 30 mm with three different tool rotational speeds such as 600 rpm, 800 rpm and 1200 rpm have been used to weld the joints. The welded samples were tested for mechanical properties as well as microstructure. It was observed that 30 mm tool gives better weld quality for friction stir welding of similar aluminum alloy but 25 mm tool with 1200 rpm rotational speed gave satisfactory weld quality for friction stir welding of dissimilar aluminum alloys. It is one of the important welding process that can adopted for welding of aluminum alloys with excellent mechanical properties. The results were confirmed by further experiments.

  12. Experimental determination of the critical welding speed in high speed MAG welding

    Institute of Scientific and Technical Information of China (English)

    Hu Zhikun; Wu Chuansong

    2008-01-01

    In high speed MAG welding process, some weld formation defects may be encountered. To get good weld quality, the critical welding speed beyond which humping or undercutting weld bead can occur must be known for different conditions. In this research, high speed MAG welding tests were carried out to check out the effects of different factors on the critical welding speed. Through observing the weld bead profiles and the macrographs of the transverse sections of MAG welds, the occurrence tendency of humping weld was analyzed, and the values of critical welding speed were determined under different levels of welding current or voltage, and the effect of shielding gas compositions on the critical welding speed was also investigated.

  13. A control system for uniform bead in fillet arc welding on tack welds

    International Nuclear Information System (INIS)

    Positioning a workpiece accurately and preventing weld distortion, tack welding is often adopted before main welding in the construction of welded structures. However, this tack weld deteriorates the final weld bead profile, so that the grinding process is usually performed for a uniform weld bead profile. In this study, a control system for uniform weld bead is proposed for the fillet arc welding on tack welds. The system consists of GMA welding machine, torch manipulator, laser vision sensor for measuring the tack weld size and the database for optimal welding conditions. Experiments have been performed for constructing the database and for evaluating the control capability of the system. It has been shown that the system has the capability to smooth the bead at the high level of quality

  14. Effects of Fusion Tack Welds on Self-Reacting Friction Stir Welds

    Science.gov (United States)

    Nunes, A. C., Jr.; Pendleton, M. L.; Brooke, S. A.; Russell, C. K.

    2012-01-01

    In order to know whether fusion tack welds would affect the strength of self-reacting friction stir seam welds in 2195-T87 aluminum alloy, the fracture stresses of 144 tensile test coupons cut from 24 welded panels containing segments of friction stir welds were measured. Each of the panels was welded under unique processing conditions. A measure of the effect of the tack welds for each panel was devised. An analysis of the measures of the tack weld effect supported the hypothesis that fusion tack welds do not affect the strength of self-reacting friction stir welds to a 5% level of confidence.

  15. Enhanced methodologies used for the assessment of high-temperature header girth welds

    International Nuclear Information System (INIS)

    Inspections performed during 2003 and 2004, have shown a significant increase in the number of occurrences of advanced cracking in superheater and reheat header girth welds. These cracks have been observed:- at several plants within different utilities; - in both header body girth welds and header-to-tee girth welds; - in headers of different manufacturers and - in headers with and without ligament or stub tube weld cracking. In addition, there has also been an increase in the number of main steam and hot reheat piping girth weld failures that exhibit characteristics similar to the aforementioned header girth weld cracking. In a number of incidences cracking has been confirmed to have initiated mid-wall and in some cases propagated to through-wall failure. The use of linear phased array ultrasonic testing (UT) has been shown to be effective: - in determining girth weld profiles, - in the detection and sizing of macro-cracking, and - in locating macro-damage relative to the weld geometry. Similarly, annular phased array UT has been shown to be effective in the detection of incipient creep cavity development before the onset of microcracking. In addition, long-range guided wave UT has been used on piping systems to determine the location and type (e.g., field or shop) welds without extensive scaffolding or insulation removal and with the anticipated advantage of being a screening technology for welds with extensive cracking. This paper will present Structural Integrity Associates (SI) experience with high-temperature header girth weld cracking and the enhanced non-destructive examination (NDE) techniques applied to the detection and quantification of damage

  16. Development of micro machining tools for finishing weld joint

    International Nuclear Information System (INIS)

    GE, Hitachi and Toshiba are jointly constructing advanced boiling water reactor (ABWR) Units 6 and 7 at Kashiwazaki Kariwa Nuclear Power Plant Station, Tokyo Electric Power Co. The ABWR features enhanced operability and safety as a whole plant through simplicity and improved performance. To achieve these improvement, one of the key features of technical innovation adopted in the ABWR design, ten reactor internal pumps (RIP) are adopted as the reactor recirculation system. The RIP casing to hold the RIP constituting the primary pressure boundary together with a RPV is welded to the nozzle on a RPV lower shell with Gas Tungsten Arc Welding (GTAW). The welding is on V-groove using automatic GTAW technique from the inside of the casing. The penetration bead (the back side of the weld) therefore needs to be finished with machining tools to inspect the qualification of the welding. This paper summarizes the development of the special purpose micro machines which are installed inside the narrow gap being provided between the RIP casing and the RPV (skirt) to finish the penetration bead. (author)

  17. Modeling corrosion behavior of gas tungsten arc welded titanium alloy

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The pitting corrosion characteristics of pulse TIG welded Ti-6Al-4V titanium alloy in marine environment were explained.Besides the rapid advance of titanium metallurgy, this is also due to the successful solution of problems associated with the development of titanium alloy welding. The preferred welding process of titanium alloy is frequently gas tungsten arc(GTA) welding due to its comparatively easier applicability and better economy. In the case of single pass GTA welding of thinner section of this alloy, the pulsed current has been found beneficial due to its advantages over the conventional continuous current process. The benefit of the process is utilized to obtain better quality titanium weldments. Four factors, five levels, central composite, rotatable design matrix are used to optimize the required number of experiments. The mathematical models have been developed by response surface method(RSM). The results reveal that the titanium alloy can form a protective scale in marine environment and is resistant to pitting corrosion. Experimental results are provided to illustrate the proposed approach.

  18. Residual stress reduction in the penetration nozzle weld joint by overlay welding

    International Nuclear Information System (INIS)

    Highlights: • Residual stress reduction in penetration weld nozzle by overlay welding was studied. • The overlay weld can decrease the residual stress in the weld root. • Long overlay welding is proposed in the actual welding. • Overlay weld to decrease residual stress is more suitable for thin nozzle. - Abstract: Stress corrosion cracking (SCC) in the penetration nozzle weld joint endangers the structural reliability of pressure vessels in nuclear and chemical industries. How to decrease the residual stress is very critical to ensure the structure integrity. In this paper, a new method, which uses overlay welding on the inner surface of nozzle, is proposed to decrease the residual stresses in the penetration joint. Finite element simulation is used to study the change of weld residual stresses before and after overlay welding. It reveals that this method can mainly decrease the residual stress in the weld root. Before overlay welding, large tensile residual stresses are generated in the weld root. After overlay weld, the tensile hoop stress in weld root has been decreased about 45%, and the radial stress has been decreased to compressive stress, which is helpful to decrease the susceptibility to SCC. With the increase of overlay welding length, the residual stress in weld root has been greatly decreased, and thus the long overlay welding is proposed in the actual welding. It also finds that this method is more suitable for thin nozzle rather than thick nozzle

  19. Health hazards of welding fumes

    International Nuclear Information System (INIS)

    Even in the twenty -first century , welding is still a common and high skilled occupation. The hazardous agents associated with welding processes are acetylene, carbomonoxide, oxides of nitrogen, ozone, phosgene, tungsten, arsenic, beryllium, cadmium, iron, copper, lead, manganese, nickel, silver,tin and zinc.All welding processes involve the potential hazards for inhalation exposures that may lead to acute or chronic respiratory diseases. According to literature described earlier it has been suggested that welding fumes cause the lung function impairment, obstructive and restrictive,lungs diseases diseases, cough, dyspnea, rhinitis, asthama, pneumoconiosis, carcinoma of the lungs. In additon,welding workers suffer from eye problems like irritation, phtokeratitis, cataract, skin irritation, erythema, petrygium, non-melanosytic skin cancer, malignant melanoma, reduced sperm count , motility and infertility. Most of the studies have been attempted previously to evaluate the effects of weldig fumes.However no cllectively effort illuminating the general effects of welding fumes on differnt organs or systems or both in humans has not been published. Therefore, the aim of this review is to gather the potential toxic effects of welding fumes documented by individual efforts and provides information to community on hazards of welding. (author)

  20. Single mode glass fiber welding

    Science.gov (United States)

    Nelson, M. D.; Fearnehough, H. T.; Goldstein, R.; Goss, W. C.

    1979-01-01

    The electric-arc welding of commercially available single-mode optical fiber has been demonstrated. A mean transmission of 92% and a maximum transmission of 98% are reported for welds of fiber waveguide of 4.5 microns core diameter.

  1. Vision-based detection of MAG weld pool

    Institute of Scientific and Technical Information of China (English)

    Gao Jinqiang; Wu Chuansong; Zhang Min; Zhao Yanhua

    2007-01-01

    Weld pool contains significant information about the welding process. The weld pool images of MAG welding are detected by LaserStrobe system. An algorithm for extracting weld pool edge is proposed according to the characteristics of MAG weld pool images. The maximum weld pool length and width are calculated. The measurement data can be used to verify the results of welding process simulation and to provide a good foundation for automatic control of MAG welding process.

  2. Inverter DC resistance spot welding of magnesium alloy AZ31

    OpenAIRE

    Hwang, I. S.; D. C. Kim; Kang, M. J.

    2011-01-01

    Purpose: The welding lobes of AC resistance spot welding and inverter DC resistance spot welding for the magnesium alloy sheet AZ31 were compared and analyzed.Design/methodology/approach: Using the welding lobe in terms of electrode force, weld time, and weld current which are process variables of the resistance spot welding, optimal welding conditions were determined. The lower limit of the range of the optimal welding condition was decided by minimum shear tension strength for the magnesium...

  3. A review on the welding technology for the sealing of irradiation test fuel element

    Energy Technology Data Exchange (ETDEWEB)

    Lee, J. W.; Kang, Y. H.; Kim, B. G.; Joo, K. N.; Oh, J. M.; Park, S. J.; Shin, Y. T

    2000-02-01

    For the irradiation test of nuclear fuel in a research reactor, the fuel manufacturing technology should be developed in advance. Highly radioactive fission products are produced and can be released from the fuel materials during irradiation. Therefore, The sealing of the test is one of the most important procedure among the test fuel manufacturing processes, considering its impacts on the safety of a reactor operation.many welding techniques such as TIG, EBW, LBW, upset butt welding and flash welding are applied in sealing the end of fuel elements. These welding techniques are adopted in conjunction with the weld material, weldability, weld joint design and cost effectiveness. For fuel irradiation test, the centerline temperature of fuel pellets is one of the important item to be measured. For this, a thermocouple is installed into the center of the fuel pellet. The sealing of the penetration hole of the thermocouple sheath should be conducted and the hole should be perfectly sealed using the dissimilar metal joining technique. For this purpose, the dissimilar metal welding between zircaloy-4 and Inconel or stainless steel is needed to be developed. This report describes the techniques sealing the end cap and the penetration of a thermocouple sheath by welding. (author)

  4. Simulation and experimental study on distortion of butt and T-joints using WELD PLANNER

    International Nuclear Information System (INIS)

    This paper investigates the capability of linear thermal elastic numerical analysis to predict the welding distortion that occurs due to GMAW process. Distortion is considered as the major stumbling block that can adversely affect the dimensional accuracy and thus lead to expensive corrective work. Hence, forecast of distortion is crucially needed and ought to be determined in advance in order to minimize the negative effects, improve the quality of welded parts and finally to reduce the production costs. In this study, the welding deformation was simulated by using relatively new FEM software WELD PLANNER developed by ESI Group. This novel Welding Simulation Solution was employed to predict welding distortion induced in butt and T-joints with thickness of 4 mm. Low carbon steel material was used for the simulation and experimental study. A series of experiments using fully automated welding process were conducted for verification purpose to measure the distortion. By comparing between the simulation and experimental results, it was found out that this program code offered fast solution analysis time in estimating weld induced distortion within acceptable accuracy

  5. Pulsed Nd-YAG laser welding of Prototype Fast Breeder Reactor fuel elements

    International Nuclear Information System (INIS)

    End plug welding of Prototype Fast Breeder Reactor (PFBR) fuel elements involves welding of fully Austenitic Stainless Steel (ASS) of grade D9 clad tube with 316M end plug. Pulsed Gas Tungsten Arc Welding (GTAW) is being used for the production of PFBR fuel elements at Advanced Fuel Fabrication Facility (AFFF). GTAW is an established process for end plug welding and hence adopted by many countries. GTAW has got certain limitations like heat input, arc gap sensitivity and certain sporadic defects like tungsten inclusion. Experiments have been carried out at AFFF to use Laser Beam Welding (LBW) technique as LBW offers a number of advantages over the former process. This report mainly deals with the optimization of laser parameters for welding of PFBR fuel elements. To facilitate pulsed Nd-YAG laser spot welding, parameters like peak power, pulse duration, pulse energy, frequency and defocusing of laser beam on to the work piece have been optimized. On the basis of penetration requirement laser welding parameters have been optimized. (author)

  6. Material Flow and Oxide Particle Distributions in Friction-Stir Welded F/M-ODS Sheets

    International Nuclear Information System (INIS)

    It is well known that uniform nano-oxide dispersoids act as pinning points to obstruct dislocation and grain boundary motion in ODS(Oxide dispersion strengthened) steel. However, these advantages will disappear while the material is subjected to the high temperature of conventional fusion welding. There is only limited literature available on the joining of ODS steels. Friction stir welding (FSW) is considered to be the best welding technique for welding ODS steels as the technique helps in retaining the homogeneous nano-oxide particles distributions in matrix. FSW is a solid.state, hot.shear joining process in which a rotating tool with a shoulder and terminating in a threaded pin, moves along the butting surfaces of two rigidly clamped plates placed on a backing plate. Heat generated by friction at the shoulder and to a lesser extent at the pin surface, softens the material being welded. Severe plastic deformation and flow of this plasticised metal occurs as the tool is translated along the welding direction. Material is transported from the front of the tool to the trailing edge where it is forged into a joint. Friction stir welding appears to be a very promising technique for the welding of FMS and ODS steels. This study found that, during FSW, the forward movement of the tool pin results in loose contact between the tool pin and the receding material on the advancing side

  7. Material Flow and Oxide Particle Distributions in Friction-Stir Welded F/M-ODS Sheets

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Suk Hoon; Noh, Sanghoon; Jin, Hyun Ju; Kim, Tae Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    It is well known that uniform nano-oxide dispersoids act as pinning points to obstruct dislocation and grain boundary motion in ODS(Oxide dispersion strengthened) steel. However, these advantages will disappear while the material is subjected to the high temperature of conventional fusion welding. There is only limited literature available on the joining of ODS steels. Friction stir welding (FSW) is considered to be the best welding technique for welding ODS steels as the technique helps in retaining the homogeneous nano-oxide particles distributions in matrix. FSW is a solid.state, hot.shear joining process in which a rotating tool with a shoulder and terminating in a threaded pin, moves along the butting surfaces of two rigidly clamped plates placed on a backing plate. Heat generated by friction at the shoulder and to a lesser extent at the pin surface, softens the material being welded. Severe plastic deformation and flow of this plasticised metal occurs as the tool is translated along the welding direction. Material is transported from the front of the tool to the trailing edge where it is forged into a joint. Friction stir welding appears to be a very promising technique for the welding of FMS and ODS steels. This study found that, during FSW, the forward movement of the tool pin results in loose contact between the tool pin and the receding material on the advancing side.

  8. Effect of Preheating in Hybrid Friction Stir Welding of Aluminum Alloy

    Science.gov (United States)

    Yaduwanshi, D. K.; Bag, S.; Pal, S.

    2014-10-01

    The controlled energy input into the system by introducing an extra heat source to enhance the material flow along with reduction of the plunging force remains a potential area of considerate for the development of hybrid friction stir welding (FSW) process. Hence, the effect of preheating on the weld joint properties is evaluated using plasma-assisted friction stir welding (P-FSW) process for joining aluminum alloy. A comparative study of mechanical and macro-microstructural characterizations of weld joint by FSW and P-FSW has been performed. Transverse tensile strength of weld joint is approximately 95% of base metal produced by P-FSW and is 8% more than conventional FSW welds. The effect of preheating enhances material flow and dissolution of fine oxide particles by plasma arc results in increase of strength and marginal modification of deformation behavior. The preheating brings uniformly distributed hardness in weld zone and the magnitude is higher in the advancing side with overall increase in average hardness value. Grain sizes are much finer due to the pinning effect of Al2O3 particles that retarded grain growth following recrystallization during P-FSW and thus led to more pronounced reduction in grain size and relatively brittle fracture during tensile loading of welded joint. Overall, the influence of preheating acts quite homogeneously throughout the structure as compared to conventional FSW. However, the results reveal that the development of P-FSW is still in initial stage and needs to improve in various aspects.

  9. Development of PRW welding technology for 9Cr-ODS cladding tube

    International Nuclear Information System (INIS)

    Oxide dispersion strengthened (ODS) ferritic steel is a very promising advanced cladding material for sodium-cooled fast reactors. Its excellent swelling resistance and high temperature strength are expected to allow a target discharge average burn-up of 150 GWd/t to be attained. Conventional TIG welding technology cannot be applied to ODS welding, because the necessary mechanical strength is not obtained due to the formation of pores and coarse oxide particles in the weld zone. Therefore development of pressurized resistance welding (PRW) technology for ODS cladding was developed. For post welding technologies, high frequency inducement heating equipment for heat treatment and a high frequency point focus type ultrasonic testing device were also developed. Mechanical strength tests such as tensile tests, burst tests, internally pressurized creep rupture tests, and rotating bending fatigue tests were conducted to verify the integrity of the weld zone by the PRW. Totally twelve PRW weld ODS fuel pins were irradiated in the BOR-60 under the framework of collaborative work by the Japan Atomic Energy Agency and Research Institute of Atomic Reactors. Integrity of the weld zone up to 25 dpa was demonstrated from post irradiation examination results. (author)

  10. Laser welding of tailored blanks

    International Nuclear Information System (INIS)

    Laser welding has an increasing role in the automotive industry, namely on the sub-assemblies manufacturing. Several sheet-shape parts are laser welded, on a dissimilar combination of thicknesses and materials, and are afterwards formed (stamped) being transformed in a vehicle body component. In this paper low carbon CO2 laser welding, on the thicknesses of 1,25 and 0.75 mm, formability investigation is described. There will be a description of how the laser welded blanks behave in different forming tests, and the influence of misalignment and undercut on the formability. The quality is evaluated by measuring the limit strain and limit effective strain for the laser welded sheets and the base material, which will be presented in a forming limit diagram. (Author) 14 refs

  11. Reduction of Biomechanical and Welding Fume Exposures in Stud Welding.

    Science.gov (United States)

    Fethke, Nathan B; Peters, Thomas M; Leonard, Stephanie; Metwali, Mahmoud; Mudunkotuwa, Imali A

    2016-04-01

    The welding of shear stud connectors to structural steel in construction requires a prolonged stooped posture that exposes ironworkers to biomechanical and welding fume hazards. In this study, biomechanical and welding fume exposures during stud welding using conventional methods were compared to exposures associated with use of a prototype system that allowed participants to weld from an upright position. The effect of base material (i.e. bare structural beam versus galvanized decking) on welding fume concentration (particle number and mass), particle size distribution, and particle composition was also explored. Thirty participants completed a series of stud welding simulations in a local apprenticeship training facility. Use of the upright system was associated with substantial reductions in trunk inclination and the activity levels of several muscle groups. Inhalable mass concentrations of welding fume (averaged over ~18 min) when using conventional methods were high (18.2 mg m(-3) for bare beam; 65.7 mg m(-3) for through deck), with estimated mass concentrations of iron (7.8 mg m(-3) for bare beam; 15.8 mg m(-3) for through deck), zinc (0.2 mg m(-3) for bare beam; 15.8 mg m(-3) for through deck), and manganese (0.9 mg m(-3) for bare beam; 1.5 mg m(-3) for through deck) often exceeding the American Conference of Governmental Industrial Hygienists Threshold Limit Values (TLVs). Number and mass concentrations were substantially reduced when using the upright system, although the total inhalable mass concentration remained above the TLV when welding through decking. The average diameters of the welding fume particles for both bare beam (31±17 nm) through deck conditions (34±34 nm) and the chemical composition of the particles indicated the presence of metallic nanoparticles. Stud welding exposes ironworkers to potentially high levels of biomechanical loading (primarily to the low back) and welding fume. The upright system used in this study improved exposure

  12. Friction Stir Welding of Aluminum Alloys

    Institute of Scientific and Technical Information of China (English)

    FU Zhi-hong; HE Di-qiu; WANG Hong

    2004-01-01

    Friction stir welding(FSW), a new solid-state welding technology invited in the early 1990s,enables us weld aluminum alloys and titanium alloys etc. The processing of FSW, the microstructure in FSW alloysand the factors influencing weld quality are introduced. The complex factors affecting the properties are researched.

  13. 49 CFR 179.300-9 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.300-9 Section 179.300-9... Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-9 Welding. (a) Longitudinal... fusion welded on class DOT-110A tanks. Welding procedures, welders and fabricators must be approved...

  14. CLASSIFICATION OF PULSE ARC WELDING PROCESSES

    OpenAIRE

    KRAMPIT A.G.; KRAMPIT N.Y.; KRAMPIT M.A.; DMITRIEVA A.V.

    2012-01-01

    Pulse welding processes improve productivity; also they allow welding of thin sheets of metal without penetration. Splashing and expenses for cleaning surfaces from droplets are also reduced. Pulse welding processes have a wholesome effect on seam formation at the expenses of thermal exposure on welding puddle and HAZ.

  15. METHOD AND SYSTEM FOR LASER WELDING

    DEFF Research Database (Denmark)

    2008-01-01

    The invention relates to laser welding of at least two adjacent, abutting or overlapping work pieces in a welding direction using multiple laser beams guided to a welding region, wherein at least two of the multiple laser beams are coupled into the welding region so as to form a melt and at least...

  16. 29 CFR 1910.255 - Resistance welding.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Resistance welding. 1910.255 Section 1910.255 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Welding, Cutting and Brazing § 1910.255 Resistance welding. (a.... Ignitron tubes used in resistance welding equipment shall be equipped with a thermal protection switch....

  17. Temperature comparison of initial, middle and final point of polypropylene friction stir welded

    Science.gov (United States)

    Kusharjanta, Bambang; Raharjo, Wahyu P.; Triyono

    2016-03-01

    Friction Stir Welding is known as a new solid state joining process. This process is applied in thermoplastic polymers material recently. One of member thermoplastic polymer is polypropylene. Polypropylene sheet 6 mm thick was friction stir welded with a cone cut steel pin. Tool rotation, travelling speed, and plunge depth, as welding parameters were 620 rpm, 7.3 mm/minutes and 0.02 mm respectively. Temperature at the initial, middle, and final point of advance side working piece were measured and compared. Measurement were done by thermocouple and recorded by data acquisition. Based on this research, it is concluded that temperature at the initial, middle and final point of friction stir welding process are different. The highest temperature peak reach at the middle point on the advance side which affects face bending strength.

  18. Weld-cost saving accomplished by replacing single-wire submerged arc welding with triple-wire welding

    OpenAIRE

    Bajcer, Božidar; Umek, I.; Tušek, Janez

    2015-01-01

    A comparison is made of different submerged arc welding processes, that is ones using singlewire, twin-wire and triple-wire electrodes, applied to welding of two webs consisting of L sections 16x90x4100 mm in size. Experimental welding, measurement of welding parameters, calculation of the melting rate, measurement and calculation of shielding flux consumption, a visual examination of the welds made, an analysis of macro sections, and an economic calculation of the respective total cost of th...

  19. Porosity in millimeter-scale welds of stainless steel : three-dimensional characterization.

    Energy Technology Data Exchange (ETDEWEB)

    Aagesen, Larry K. (University of Michigan, Ann Arbor, MI); Madison, Jonathan D.

    2012-05-01

    A variety of edge joints utilizing a continuous wave Nd:YAG laser have been produced and examined in a 304-L stainless steel to advance fundamental understanding of the linkage between processing and resultant microstructure in high-rate solidification events. Acquisition of three-dimensional reconstructions via micro-computed tomography combined with traditional metallography has allowed for qualitative and quantitative characterization of weld joints in a material system of wide use and broad applicability. The presence, variability and distribution of porosity, has been examined for average values, spatial distributions and morphology and then related back to fundamental processing parameters such as weld speed, weld power and laser focal length.

  20. Friction Stir Welding: Standards and Specifications in Today's U.S. Manufacturing and Fabrication

    Science.gov (United States)

    Ding, Robert Jeffrey

    2008-01-01

    New welding and technology advancements are reflected in the friction stir welding (FSW) specifications used in the manufacturing sector. A lack of publicly available specifications as one of the reasons that the FSW process has not propagate through the manufacturing sectors. FSW specifications are an integral supporting document to the legal agreement written between two entities for deliverable items. Understanding the process and supporting specifications is essential for a successful FSW manufacturing operation. This viewgraph presentation provides an overview of current FSW standards in the industry and discusses elements common to weld specifications.

  1. Development of automatic laser welding system

    International Nuclear Information System (INIS)

    Laser are a new production tool for high speed and low distortion welding and applications to automatic welding lines are increasing. IHI has long experience of laser processing for the preservation of nuclear power plants, welding of airplane engines and so on. Moreover, YAG laser oscillators and various kinds of hardware have been developed for laser welding and automation. Combining these welding technologies and laser hardware technologies produce the automatic laser welding system. In this paper, the component technologies are described, including combined optics intended to improve welding stability, laser oscillators, monitoring system, seam tracking system and so on. (author)

  2. Developments in tube to tubeplate welding

    International Nuclear Information System (INIS)

    The paper deals with the development of a bore welding technique that has been applied in the production of boilers for nuclear power stations. After a description of the weld geometry and the basic welding process, the discussion covers the work necessary to establish the welding parameters and the associated development of welding torches and welding programme controllers. An account is given of some methods that have been employed to overcome certain metallurgical/ welding process problems together with the development of non-destructive testing techniques. (author)

  3. Plasma spot welding of ferritic stainless steels

    International Nuclear Information System (INIS)

    Plasma spot wedding of ferritic stainless steels studied. The study was focused on welding parameters, plasma and shieldings and the optimum welding equipment. Plasma-spot welded overlap joints on a 0.8 mm thick ferritic stainless steel sheet were subjected to a visual examination and mechanical testing in terms of tension-shear strength. Several macro specimens were prepared Plasma spot welding is suitable to use the same gas as shielding gas and as plasma gas , i. e. a 98% Ar/2% H2 gas mixture. Tension-shear strength of plasma-spot welded joint was compared to that of resistance sport welded joints. It was found that the resistance welded joints withstand a somewhat stronger load than the plasma welded joints due to a large weld sport diameter of the former. Strength of both types of welded joints is approximately the same. (Author) 32 refs

  4. Devices for on-site maintenance allows an increased availability of supplies of orbital welding systems

    International Nuclear Information System (INIS)

    Until now, energy supplies of orbital welding systems had to be shipped for maintenance. As described in this article, technological advances like portable calibration units allow the owners of such systems to perform themselves maintenance operations. On-site calibration results in a reduction of costs and off-site maintenance, therefore in an increased availability. The article describes the main functions of these portable calibration units which are used to calibrate welding critical variables

  5. Investigation into Variations of Welding Residual Stresses and Redistribution Behaviors for Different Repair Welding Widths

    International Nuclear Information System (INIS)

    In this study, we investigated the variations in welding residual stresses in dissimilar metal butt weld due to width of repair welding and re-distribution behaviors resulting from similar metal welding (SMW) and mechanical loading. To this end, detailed two-dimensional axi-symmetric finite element (FE) analyses were performed considering five different repair welding widths. Based on the FE results, we first evaluated the welding residual stress distributions in repair welding. We then investigated the re-distribution behaviors of the residual stresses due to SMW and mechanical loads. It is revealed that large tensile welding residual stresses take place in the inner surface and that its distribution is affected, provided repair welding width is larger than certain value. The welding residual stresses resulting from repair welding are remarkably reduced due to SMW and mechanical loading, regardless of the width of the repair welding

  6. DETECTION AND ANALYSIS OF WELD POOL SHAPE FOR CO2 SHORT CIRCUITING ARC WELDING

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A general industrial CCD(ICCD) camera is redesigned to detect the weld pool without arc at the period of short circuiting,so that the interference of arc and spatter during CO2 short circuiting arc welding is eliminated. Through the analysis of weld pool image, both size parameters (such as weld pool area A, weld pool length L1, L2 and weld pool breadth b) and contour parameters (bi which describe the curves of weld pool boundany) ,which could indicate the shape features of weld pool, had been defined to express weld pool information quantitatively. The investigation of the relationships between weld pool shape parameters and welding process parameters may be beneficial to the quality control of CO2 welding.

  7. Sensor integration for robotic laser welding processes

    OpenAIRE

    Iakovou, Dimitrios; Aarts, Ronald; Meijer, Johan

    2005-01-01

    The use of robotic laser welding is increasing among industrial applications, because of its ability to weld objects in three dimensions. Robotic laser welding involves three sub-processes: seam detection and tracking, welding process control, and weld seam inspection. Usually, for each sub-process, a separate sensory system is required. The use of separate sensory systems leads to heavy and bulky tools, in contrast to compact and light sensory systems that are needed to reach sufficient accu...

  8. Collection of arc welding process data

    OpenAIRE

    K. Luksa; Z. Rymarski

    2006-01-01

    Purpose: The aim of the research was to examine the possibility of detecting welding imperfections by recording the instant values of welding parameters. The microprocessor controlled system for real-time collection and display of welding parameters was designed, implemented and tested.Design/methodology/approach: The system records up to 4 digital or analog signals collected from welding process and displays their run on the LCD display. To disturb the welding process artificial disturbances...

  9. Mechanical characterisation and modelling of resistance welding

    OpenAIRE

    Van Rymenant, Patrick

    2011-01-01

    Resistance welding is used very extensively in industry for a wide range of applications. Knowledge and measurement of the dynamic characteristics of resistance welding equipment is important in the design of the equipment and in optimization of welding procedures using finite element software. This is especially true for projection welding where accurate measurements of effective lumped mass and damping of the welding head as well as its maximal acceleration and velocity are required for acc...

  10. Fundamental Difficulties Associated With Underwater Wet Welding

    Directory of Open Access Journals (Sweden)

    Joshua E. Omajene,

    2014-06-01

    Full Text Available The offshore industries carry out welding activities in the wet environment. It is evident that the wet environments possess difficulties in carrying out underwater welding. Therefore there is the need to improve the quality of weld achieved in underwater welding. This paper investigates the difficulties associated with underwater welding. The objective of this research paper is to identify and analyze the different difficulties in underwater welding so as to make a clear background for further research to identifying the processes of eliminating these difficulties. The major difficulties in underwater welding are the cooling rate of the weld metal and arc stability during underwater wet welding at a higher depth. Methods of decreasing the cooling rate of weld metal and how to achieve arc stability are the major methods of approach. The result of welds achieved in underwater welding will be much improved as compared to air welding if the effects of the difficulties associated with underwater welding are eliminated. This will lead to a more robust welding activities being carried out underwater.

  11. Study of Gasdynamic Effect Upon the Weld Geometry When Concumable Electrode Welding

    Science.gov (United States)

    Chinakhov, D. A.; Grigorieva, E. G.; Mayorova, E. I.

    2016-04-01

    The paper considers the ways of weld geometry controlling when consumable electrode welding under single-jet and double-jet gas shielding. The authors provide comparative results of experimental studies on the effects of shielding gas supply upon the weld geometry in weld joints produced from construction carbon steel 45. It has been established that gas-dynamic effect of the shielding gas has a significant impact upon shaping and weld geometry when consumable electrode welding under double-jet gas shielding.

  12. A Comparative Study of Welded ODS Cladding materials for AFCI/GNEP Applications

    International Nuclear Information System (INIS)

    This research project involved working on the pressure resistance welding of oxide dispersion strengthened (ODS) alloys which will have a large role to play in advanced nuclear reactors. The project also demonstrated the research collaboration between four universities and one nation laboratory (Idaho National Laboratory) with participation from an industry for developing for ODS alloys. These alloys contain a high number density of very fine oxide particles that can impart high temperature strength and radiation damage resistance suitable for in-core applications in advanced reactors. The conventional fusion welding techniques tend to produce porosity-laden microstructure in the weld region and lead to the agglomeration and non-uniform distribution of the needed oxide particles. That is why two solid state welding methods - pressure resistance welding (PRW) and friction stir welding (FSW) - were chosen to be evaluated in this project. The proposal is expected to support the development of Advanced Burner Reactors (ABR) under the GNEP program (now incorporated in Fuel Cycle R and D program). The outcomes of the concluded research include training of graduate and undergraduate students and get them interested in nuclear related research.

  13. A Comparative Study of Welded ODS Cladding materials for AFCI/GNEP Applications

    Energy Technology Data Exchange (ETDEWEB)

    Indrajit Charit; Megan Frary; Darryl Butt; K.L. Murty; Larry Zirker; James Cole; Mitchell Meyer; Rajiv S. Mishra; Mark Woltz

    2011-03-31

    This research project involved working on the pressure resistance welding of oxide dispersion strengthened (ODS) alloys which will have a large role to play in advanced nuclear reactors. The project also demonstrated the research collaboration between four universities and one nation laboratory (Idaho National Laboratory) with participation from an industry for developing for ODS alloys. These alloys contain a high number density of very fine oxide particles that can impart high temperature strength and radiation damage resistance suitable for in-core applications in advanced reactors. The conventional fusion welding techniques tend to produce porosity-laden microstructure in the weld region and lead to the agglomeration and non-uniform distribution of the neededoxide particles. That is why two solid state welding methods - pressure resistance welding (PRW) and friction stir welding (FSW) - were chosen to be evaluated in this project. The proposal is expected to support the development of Advanced Burner Reactors (ABR) under the GNEP program (now incorporated in Fuel Cycle R&D program). The outcomes of the concluded research include training of graduate and undergraduate students and get them interested in nuclear related research.

  14. Optimisation of laser welding parameters for welding of P92 material using Taguchi based grey relational analysis

    Directory of Open Access Journals (Sweden)

    Shanmugarajan B.

    2016-08-01

    Full Text Available Creep strength enhanced ferritic (CSEF steels are used in advanced power plant systems for high temperature applications. P92 (Cr–W–Mo–V steel, classified under CSEF steels, is a candidate material for piping, tubing, etc., in ultra-super critical and advanced ultra-super critical boiler applications. In the present work, laser welding process has been optimised for P92 material by using Taguchi based grey relational analysis (GRA. Bead on plate (BOP trials were carried out using a 3.5 kW diffusion cooled slab CO2 laser by varying laser power, welding speed and focal position. The optimum parameters have been derived by considering the responses such as depth of penetration, weld width and heat affected zone (HAZ width. Analysis of variance (ANOVA has been used to analyse the effect of different parameters on the responses. Based on ANOVA, laser power of 3 kW, welding speed of 1 m/min and focal plane at −4 mm have evolved as optimised set of parameters. The responses of the optimised parameters obtained using the GRA have been verified experimentally and found to closely correlate with the predicted value.

  15. 10,170 flawless welds

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

    The welding of tubes containing the principal current-carrying busbars in the LHC magnets was one of the main activities of the SMACC project. After a year of preparation and another of intense activity in the tunnel, the last weld was completed on Wednesday 14 May. Over 10,170 welds have been inspected and not a single fault has been found.    The welder (above) creates the weld using an orbital welding machine (below) specifically designed for CERN. Each of the eight sectors of the LHC contains around 210 interconnects between the superconducting magnets. Consolidating these interconnections was the SMACC project’s primary objective. One of the last jobs before closing the interconnects is the welding of the M lines: each has a 104 mm diameter and a radial clearance of just 45 mm. In total: 10,170 welds carried out in a single year of activities. A true challenge, which was carried out by a team of 30 highly specialised welders, working under the supervision o...

  16. The Revolutionary Armed Forces of Colombia (FARC and the Development of Narco-Submarines

    Directory of Open Access Journals (Sweden)

    Michelle Jacome Jaramillo

    2016-03-01

    Full Text Available The Revolutionary Armed Forces of Colombia (FARC have been one of the world's most consistently formidable violent non-state actors over the last forty years. Unsurprisingly, the group has provided one of the most compelling and concerning examples of the level of technical sophistication attainable by sub-state organizations. Over the last two decades the group has carried out an iterative and innovative process that, in reaction to improved detection capabilities, has brought them from depending on disposable go-fast boats to transport drugs to possessing fully submersible and reusable covert vessels for transportation. The following case study will discuss the development of narco-submarines and the underlying motivations behind the pursuit of this complex engineering task. The case study will outline the different phases of the narco-submarine development and highlight FARC’s determination to overcome the challenges present in each design. This discussion will show how FARC’s systematized acquiring of information and expertise has resulted in the accomplishment of fully submersible vessels, capable of transporting more than 10 tons of illicit product.

  17. Reifications of the intellectual: representations, organization and agency in revolutionary China.

    Science.gov (United States)

    U, Eddy

    2013-12-01

    How did 'intellectuals' evolve from a class of subjects in Marxian thoughts to highly visible populations under communism? Such 'reifications of the intellectual' have deeply affected subjectivity, conflict and organization, but received little attention in the political sociology of communism. This essay draws on research on classifications and social boundaries to address the objective and subjective foundations of the reifications and their impact on communist rule. The intellectual is viewed as an identification formed and performed around multiple social axes (most notably family background, educational achievement, occupational history, institutional affiliation and revolutionary rank) that reflected broader patterns of communist political domination. I use the Chinese Communist movement to demonstrate that (1) interaction of political contests, ruling strategies and institutional developments turned a diversity of persons into 'intellectuals' who were allegedly imbued with reprehensible interests and habits linked to privileged economic classes; (2) constant competitions for power and organizational changes led to classificatory ambiguities and, in turn, allowed individuals some control over their identifications; and (3) the developments profoundly influenced identity, state and class formation. Focusing on the dynamics that produced a highly visible but fluid population of 'intellectuals' opens new pathways for comparative research on communism. PMID:24320069

  18. Educational Reform and the Birth of a Mathematical Community in Revolutionary France, 1790 1815

    Science.gov (United States)

    Glas, Eduard

    Resulting from of a communal practice, scientific development is to some extent shaped by the particular conceptions of the problems, aims and methods of a field that are shared by the members of the scientific community concerned. Regrouping of scientists and the formation of a new community of practitioners reflect differentiation of the said conceptions of methods, aims and problems. In this connection, educational reform may be a key factor in the formation and consolidation of a new socio-cognitive constellation that may decisively affect the development of a discipline. A case in point is provided by the French Revolution, when radically changed social conditions gave birth to a new community of mathematical practitioners - ingénieurs savants - who shared a common education at the newly founded Ecole Polytechnique. This entirely new type of scientific institute was created in 1794 by the revolutionary Comité de Salut Public, on the instigation of its prominent member Lazare Carnot and a lobby of scientists led by Gaspard Monge, who was largely responsible for the teaching programme of the School.

  19. THE MODERN MEDIA AND THEIR EFFECT ON THE REVOLUTIONARY PROCESS «ARAB SPRING»

    Directory of Open Access Journals (Sweden)

    Murad Mohammed Ba Alawi

    2015-02-01

    Full Text Available The article is about the role that played the Internet in the organization of the occurred events of 2011 in the Arab world, the so-called «Arab spring».It has been shown how they used new media as an instrument of calls, organizing protests and exchanging information and the import of revolution from one country to another. It is revealed how the Arab events have demonstrated the importance and high efficiency of modern technologies.Purpose. To reveal the role of modern media and their influence on the revolutionary process in the Arab countries.Methodology. Applied general scientific methods of analysis and synthesis, system approach. In the process of preparations the article carried out an analysis of factual material, scientific sources, used statistical data.Results. It has been shown the absence of trust in the traditional media that belongs to the state, and mastering new technological facilities have led to an active use of the Internet as a political instrument during the «Arab Spring».

  20. Work Analysis And Autonomy - Socialisme ou Barbarie's Concept of Revolutionary Work Research

    Directory of Open Access Journals (Sweden)

    Gabler, Andrea

    2008-12-01

    Full Text Available Cornelius Castoriadis hardly fits the stereotype of the isolated thinker, who develops theories in private, far away from the world. When reading his stimulating texts, we should have in mind that they were written in a specific political context, as part of Castoriadis' own revolutionary activism. Until the mid-1960s the French group "Socialisme ou Barbarie" (hereafter: "SouB"; "SB" is used hereafter with reference to their journal with the same name was Castoriadis' political background. His works from that period were the direct expression of the group's discussions and activities.The following article deals with an example of Castoriadis' political-theoretical collaboration with SouB. After a short view at the Marxist context at that time (1., follows the description of SouB's work analysis, its main concept, results and limitations (2., from which unfolds directly Castoriadis' theory (3.. By way of conclusion I shall show some implications for today's discussions about work (4..

  1. Random Conformal Weldings

    CERN Document Server

    Astala, K; Kupiainen, A; Saksman, E

    2009-01-01

    We construct a conformally invariant random family of closed curves in the plane by welding of random homeomorphisms of the unit circle. The homeomorphism is constructed using the exponential of $\\beta X$ where $X$ is the restriction of the two dimensional free field on the circle and the parameter $\\beta$ is in the "high temperature" regime $\\beta<\\sqrt 2$. The welding problem is solved by studying a non-uniformly elliptic Beltrami equation with a random complex dilatation. For the existence a method of Lehto is used. This requires sharp probabilistic estimates to control conformal moduli of annuli and they are proven by decomposing the free field as a sum of independent fixed scale fields and controlling the correlations of the complex dilation restricted to dyadic cells of various scales. For uniqueness we invoke a result by Jones and Smirnov on conformal removability of H\\"older curves. We conjecture that our curves are locally related to SLE$(\\kappa)$ for $\\kappa<4$.

  2. Socket welding method

    International Nuclear Information System (INIS)

    Upon joining of metal tubes having a same composition, a metal having a corrosion potential higher by from 50 to 300mV than that of the metal which constitutes the metal tube is disposed at the periphery of the joint portion of the metal tubes in order to improve corrosion resistance of the joint portion of pipelines in a plant such as a nuclear reactor. In a socket joint in which metal tubes having a greater outer diameter than the inner diameter of the other are fitted to each other at the joint portion, more remarkable effect can be obtained. This is because the area of the gap portion is greater than in the case of butt welding. Further, it is preferred that a metal having a corrosion potential greater by from 50 to 300mV than that of the metal tube is interposed at least to a portion of the overlapped portion of the tubes in order to prevent corrosion of the gap portion. Then, a carbon steel pipe weld-joint having sufficiently high resistance to temperature and pressure water SCC can be attained in a BWR reactor water circumstance, and the safety of the BWR can be ensured, as well as the working life of the reactor plant can be attained. (N.H.)

  3. Friction stir welding of dissimilar joint between semi-solid metal 356 and AA 6061-T651 by computerized numerical control machine

    OpenAIRE

    Muhamad Tehyo; Prapas Muangjunburee; Somchai Chuchom

    2011-01-01

    The objective of this research is to investigate the effect of welding parameters on the microstructure and mechanicalproperties of friction stir welded butt joints of dissimilar aluminum alloy sheets between Semi-Solid Metal (SSM) 356 and AA6061-T651 by a Computerized Numerical Control (CNC) machine. The base materials of SSM 356 and AA 6061-T651 werelocated on the advancing side (AS) and on the retreating side (RS), respectively. Friction Stir Welding (FSW) parameterssuch as tool pin profil...

  4. A method of initial welding position guiding for arc welding robot based on visual servo control

    Institute of Scientific and Technical Information of China (English)

    郭振民; 陈善本; 邱涛; 吴林

    2003-01-01

    In order to solve the visual guiding task of initial welding position for arc welding robot, this paper presents a practice-prone image-based visual servo control strategy without calibration, and we perform validating experiments on a nine-DOF arc welding robot system. Experimental results illustrate presented method has the function to fulfill the task of welding robot initial positioning with certain anti-jamming ability. This method provides a basis for guiding welding gun to initial welding pose with real typical seam's image properties to replace flag block properties, and is a significant exploit to realize visual guiding of initial welding position and seam tracing in robot welding system.

  5. A study of weld quality in ultrasonic spot welding of similar and dissimilar metals

    International Nuclear Information System (INIS)

    Several difficulties are faced in joining thinner sheets of similar and dissimilar materials from fusion welding processes such as resistance welding and laser welding. Ultrasonic metal welding overcomes many of these difficulties by using high frequency vibration and applied pressure to create a solid-state weld. Ultrasonic metal welding is an effective technique in joining small components, such as in wire bonding, but is also capable of joining thicker sheet, depending on the control of welding conditions. This study presents the design, characterisation and test of a lateral-drive ultrasonic metal welding device. The ultrasonic welding horn is modelled using finite element analysis and its vibration behaviour is characterised experimentally to ensure ultrasonic energy is delivered to the weld coupon. The welding stack and fixtures are then designed and mounted on a test machine to allow a series of experiments to be conducted for various welding and ultrasonic parameters. Weld strength is subsequently analysed using tensile-shear tests. Control of the vibration amplitude profile through the weld cycle is used to enhance weld strength and quality, providing an opportunity to reduce part marking. Optical microscopic examination and scanning electron microscopy (SEM) were employed to investigate the weld quality. The results show how the weld quality is particularly sensitive to the combination of clamping force and vibration amplitude of the welding tip.

  6. Residual solidification stress in plug welds

    International Nuclear Information System (INIS)

    Installation of the plugs in Steam Generators and Heat Exchangers is performed using GTAW process with filler metal. During the cooling phase of the weld puddle residual stresses will be generated in the weld. The residual stresses together with the stresses from the primary and secondary loads will define the total stress in the weld. The level of total stress is important for the reliability of the plug joints. Typically, the welding procedures prescribe a range of values for each welding parameters, therefore the welder has the option to select a relative wide range of combinations of parameters based on test results, welding position, experience, etc. Manual welding processes are more susceptible to larger variation of the heat input than the automatic welding processes. The combination of the welding parameters may be controlled by a generic parameter called welding heat input. The net effect of the heat input is to control the energy introduced by an arc at weld joint such that adequate weld puddle is produced. The heat input along with the thermal properties of the materials control the temperature distribution in the welded joint. Ultimately, the response of the structure to the thermal loads resulted from the non-uniform distribution of temperature is a non-uniform distribution of the plastic strains that results in residual stresses. This paper presents the effect of variation of welding heat input on distribution of residual stresses. Finite element method is used to simulate the welding process for various heat inputs that may be encountered during plug welding. The analysis is performed in two steps. In the first step a thermal transient analysis is performed in which the temperature distribution due to a moving heat source is obtained. The resulting thermal field is used as input data for structural analysis. It is shown that the extent of residual stresses in the weld joint is affected by the energy used to produce the weld and can be related to the

  7. Phenomenological evaluation of laser-irradiated welding processes with a combined use of higher-accuracy experiments and computational science methodologies. (5) Numerical simulation of the welding processes with a multi-dimensional multi-physics analysis code SPLICE

    International Nuclear Information System (INIS)

    It is quite important that the establishing the welding and solidification processes, generation of the residual stress, in a laser welding for various reactor components. In order to standardize laser welding repair processes and controlling a residual stress which is induced by laser welding, we constructed the fully parallelized laser welding simulation code using one-fluid model (solid, liquid and gas phases are simultaneously calculated by one set of governing equations) and some advanced numerical models, e.g., VSIA (Volume and Surface Integrated Average) based CIP finite volume method for the discretization, the THINC/WLIC scheme for an accurate interface capturing and the robust and stable pressure Poisson equation solver, AMG preconditioned BiCGSTAB method. In the simulation, the base material is a pure aluminum which was included to the code as a physical parameter and we considered the surface tension force and its effect of a temperature gradient named Marangoni effect. As a result, reasonable results were obtained that is welding bead which is one of the representative behavior of a low power density laser welding and the appropriate shape of the vertical cross section of the molten pool. Therefore, the model can be applied to practical laser welding problems and contribute the standardization of a laser welding repair technology. (author)

  8. Plasticity Theory of Fillet Welds

    DEFF Research Database (Denmark)

    Hansen, Thomas

    2005-01-01

    This paper deals with simple methods for calculation of fillet welds based on the theory of plasticity. In developing the solutions the lower-bound theorem is used. The welding material and parts of the base material are subdivided into triangular regions with homogeneous stress fields; thereby a...... safe and statically admissible stress distribution is established. The plasticity solutions are compared with tests carried out at the Engineering Academy of Denmark, Lyngby, in the early nineties, and old fillet weld tests. The new failure conditions are in very good agreement with the yield load...

  9. Novel Process Revolutionizes Welding Industry

    Science.gov (United States)

    2008-01-01

    Glenn Research Center, Delphi Corporation, and the Michigan Research Institute entered into a research project to study the use of Deformation Resistance Welding (DRW) in the construction and repair of stationary structures with multiple geometries and dissimilar materials, such as those NASA might use on the Moon or Mars. Traditional welding technologies are burdened by significant business and engineering challenges, including high costs of equipment and labor, heat-affected zones, limited automation, and inconsistent quality. DRW addresses each of those issues, while drastically reducing welding, manufacturing, and maintenance costs.

  10. Weld bonding of stainless steel

    DEFF Research Database (Denmark)

    Santos, I. O.; Zhang, Wenqi; Goncalves, V.M.;

    2004-01-01

    This paper presents a comprehensive theoretical and experimental investigation of the weld bonding process with the purpose of evaluating its relative performance in case of joining stainless steel parts, against alternative solutions based on structural adhesives or conventional spot-welding. The...... overall assessment of the weld bonding process is made using several commercial adhesives with varying working times under different surface conditions. The quality of the resulting joints is evaluated by means of macroetching observations, tension-shear tests and peel tests. The theoretical investigation...

  11. Review of laser hybrid welding

    DEFF Research Database (Denmark)

    Bagger, Claus

    In this artucle an overview og the hybrid welding process is given. After a short historic overview, a review of the fundamental phenomenon taking place when a laser (CO2 or Nd:YAG) interacts in the same molten pool as a more conventional source of energy, e.g. tungsten in-active gas, plasma, or...... metal inactive gas/metal active gas.This is followed by reports of how the many process parameters governing the hybrid welding process can be set and how the choice of secondary energy source, shielding gas, etc. can affect the overall welding process....

  12. Strength Evaluation of Heat Affected Zone in Electron Beam Welded ARAA for HCCR TBM in ITER

    International Nuclear Information System (INIS)

    The Korean helium cooled ceramic reflector (HCCR) test blanket module (TBM) has been developed for ITER, and Korean reduced activation ferritic martensitic (RAFM) steel, called advanced reduced activation alloy (ARAA), has also been developed for a structural material of the HCCR TBM. One case of limited optimized electron beam (EB) welding conditions was selected based on previous work, and the weldability of an EB weld was evaluated for TBM fabrication. The micro-hardness was measured from the base to the weld region, and the microstructures were also observed. A small punch (SP) test considering the HAZ was carried out at room and high (550 .deg. C) temperatures. The empirical mechanical properties of HAZ in the EB weld were evaluated, and the fracture behavior was investigated after the SP test. The SP results show that the estimated yield and tensile strength of the HAZ were higher than the base metal at both temperatures. Korean RAFM steel, ARAA, was developed as a TBM structural material. Using one of the program alloys in ARAA (F206), one case of a limited optimized EB welding condition was selected based on previous works, and the weldability of an EB weld using the SP test was evaluated for TBM fabrication at room and high (550 .deg. C) temperatures. From a micro-Vickers hardness evaluation, the HAZ gave the highest values compared with the other regions. The irregular grain boundaries in the HAZ were observed, but its width was narrower than the TIG weld from the previous results. The optimized welding methods such as the TIG, EB, and laser weld, and the welding procedure considering the PWHT are being established, and the weldability evaluation is also progressing according to the development of the ARAA for the fusion material application in Korea

  13. Application of the bead flush method to welded pipes to evaluate residual stresses nondestructively

    International Nuclear Information System (INIS)

    To assess the structural integrity of welded structures during the design and in-service inspection, it is important to evaluate welding residual stresses. Recently, the design process of structures has shifted from 'the design by rule' to 'the design by analysis' using the FEM (finite element method) codes. As the design process advances, analytical processes have formed a link in the chain of manufacturing and in-service inspection procedures. Under this circumstance, authors have proposed a new method called 'the Bead Flush Method', to evaluate the welding residual stresses by utilizing the FEM data constructed during the structural design. In this method, eigenstrains as sources of residual stresses are calculated from released elastic strains after removal of reinforcement of the weld by applying the inverse analysis. Then, residual stresses as well as displacements at any location concerned are evaluated by imposing eigenstrains as initial strains in the FEM analysis. Mechanical properties required through this analysis are the elastic constants at room temperature. No further properties, such as temperature dependencies of the yield strength and the thermal coefficient, are needed. By now, we have confirmed its utility for welded plates by computer simulations and experiments. In this study, further development of this method for application to welded pipes was attempted. Despite its relatively simple shape of pipes (axe symmetrical) compared with welded plates (3-dimentional), welded pipe problems are more complicated than those of welded plates from a view point of the inverse analysis. As a first step, a basic formulization was attempted to overcome this difficulty and future problems to be solved were made clear. Then computer simulations of the bead flush method conducted for a thin walled welded pipe confirmed its utility. Refs. 2 (author)

  14. Acoustic field measurements in austenitic welds and dissimilar welds

    International Nuclear Information System (INIS)

    Acoustic field measurements were performed in identical specimen geometries of NPP components, in order to contribute the results to the interpretation of US testing results and evaluation of the testing reliability. With an electrodynamic probe of type T, the sonic fields were scanned by scanning heads at 45 T, 45 L, 60 L, and 70 L. The following selected groups of measured data are discussed in the paper: (a) acoustic fields in a narrow-gap weld and a dissimilar weld; (b) longitudinal sound impact testing of welds for detection of transverse defects; (c) variation of transmissibility of acoustic waves along a welded seam; (d) strength and range of the secondary creep wave; (e) multiply reflected sonic modes. (orig./CB)

  15. The Revolutionary Movement in the Evaluation of F.M. Dostoevsky: To Understand Conservatism in the Political History of Russia

    Directory of Open Access Journals (Sweden)

    Konstantin A. Lotarev

    2015-12-01

    Full Text Available The article attempts to show the features of the conservative worldview of F. M. Dostoevsky through the prism of his assessments of the revolutionary movement and socialist ideas in Russia. The main focus is on the analysis of artistic creativity, and journalism, especially "Diary of a Writer". This allowed us to identify the political views of F. M. Dostoevsky and the possibility of their practical implementation. It is concluded that the main cause of the political turmoil in the 1860s – early 1880s, the spread of revolutionary ideas the writer felt a deep moral crisis afflicting Russian society. Therefore, the cause of the crisis he saw not in reforming state institutions, and in fundamental moral renewal of Russian life on the basis of Christian Orthodox values.

  16. Dreaming the Chinese Dream. How the People’s Republic of China Moved from Revolutionary Goals to Global Ambitions

    Directory of Open Access Journals (Sweden)

    Stefan R. Landsberger

    2015-01-01

    Full Text Available On 1 October 2014, the People’s Republic of China (PRC will observe the 65th anniversary of its founding which ended a decades’ long period of oppression by imperialism, internal strife and (civil war. Under the Chinese Communist Party (CCP, modernisation became the most important task. Marxism-Leninism and Mao Zedong Thought guided the nation along this path that would lead to modernisation and the recognition of the new, strong China. As the first three decades passed, it became clear that ideological purity and revolutionary motivation did not lead to the realisation of the dream of rejuvenation. In late 1978, the Maoist revolutionary goals were replaced by the pragmatic policies that turned China into today’s economic powerhouse. How has this radical turn from revolution to economic development been realised? How has it affected China’s political, social and artistic cultures? Is China’s present Dream structurally different from the one cherished in 1949?

  17. Laser welding and post weld treatment of modified 9Cr-1MoVNb steel.

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z. (Nuclear Engineering Division)

    2012-04-03

    Laser welding and post weld laser treatment of modified 9Cr-1MoVNb steels (Grade P91) were performed in this preliminary study to investigate the feasibility of using laser welding process as a potential alternative to arc welding methods for solving the Type IV cracking problem in P91 steel welds. The mechanical and metallurgical testing of the pulsed Nd:YAG laser-welded samples shows the following conclusions: (1) both bead-on-plate and circumferential butt welds made by a pulsed Nd:YAG laser show good welds that are free of microcracks and porosity. The narrow heat affected zone has a homogeneous grain structure without conventional soft hardness zone where the Type IV cracking occurs in conventional arc welds. (2) The laser weld tests also show that the same laser welder has the potential to be used as a multi-function tool for weld surface remelting, glazing or post weld tempering to reduce the weld surface defects and to increase the cracking resistance and toughness of the welds. (3) The Vicker hardness of laser welds in the weld and heat affected zone was 420-500 HV with peak hardness in the HAZ compared to 240 HV of base metal. Post weld laser treatment was able to slightly reduce the peak hardness and smooth the hardness profile, but failed to bring the hardness down to below 300 HV due to insufficient time at temperature and too fast cooling rate after the time. Though optimal hardness of weld made by laser is to be determined for best weld strength, methods to achieve the post weld laser treatment temperature, time at the temperature and slow cooling rate need to be developed. (4) Mechanical testing of the laser weld and post weld laser treated samples need to be performed to evaluate the effects of laser post treatments such as surface remelting, glazing, re-hardening, or tempering on the strength of the welds.

  18. Embrittlement of welds produced by pulsed laser welding

    International Nuclear Information System (INIS)

    Welding through radiation of Nd:Yag laser is characterized by hard thermal deformation cycle under action of which the microstructure changes are obtained. These changes exert considerable influence on the mechanical properties. Experimentally investigated the influence of multipulse action on the butt weld strength at static tension. It was found that by increasing multiplicity equalled to increasing of overlapping factor the destroying stresses are decreased up to some

  19. Study of Simulated Temperature of Butt Joint during Friction Stir Welding Of Aluminium Alloy by Using Hyperworks

    Directory of Open Access Journals (Sweden)

    Mohd Anees Siddiqui

    2015-01-01

    Full Text Available Friction stir welding (FSW is one of the latest welding technology that utilizes a special tool for generation of frictional heat in the work piece by its rotation due to which joining occurs without melting of metal. For this reason friction stir welding lies under the category of solid state joining. A part from experimental work, there is large space to work on simulation of FSW by using simulation tools. In the present paper, simulation of friction stir welding of aluminium alloy AA-6061 is done by using HyperWeld module of Altair HyperWorks. The virtual experiment of friction stir welding is conducted for variable tool rotational speeds with constant travelling speed and study of simulation results of variation in temperature distribution along the weld line of butt joint is done. The results of simulation shows that the temperature is symmetrically distributed along the weld line. It is observed that the maximum temperature along the weld line increases with the increase in rotational speed. It is also observed that the temperature at advancing side is greater that retreating side.

  20. Study of laser and electron beam welding of Nb-1Zr-0.1C and TZM alloys

    International Nuclear Information System (INIS)

    The refractory metal alloys Nb-1Zr-0.1C and TZM (0.5 Ti-0.08 Zr-0.04 C) having an excellent combination of high temperature properties; which makes them suitable for structural applications in advanced nuclear reactors operating at high temperature.The applications of these alloys call for their welding in different forms and shapes. Due to their high melting point, thermal conductivity and reactive nature; welding of these alloys is challenging and difficult task. The high energy density welding techniques like laser and electron beam (EB) capable of producing deep penetration welds with minimal heat affected zone (HAZ) are more suitable for welding of these alloys. Both the techniques had some advantages and limitations which need to be studied. The autogeneous laser (Nd:YAG) and EB welds in bead-on-plate (BOP) and butt joint configuration were produced on sheets of Nb-1Zr-0.1C and TZM alloy by systematically varying the process parameters. The laser and EB welds produced on sheets of Nb-1Zr-0.1C alloy were subjected to optical and electron microscopic examination and were characterized in detailed by studying their weld profiles, optical and SEM micrographs of the weld zone and HAZ

  1. The Revolutionary Armed Forces of Colombia - People's Army (FARC-EP) Marxist-Leninist insurgency or criminal enterprise?

    OpenAIRE

    Saskiewicz, Paul E.

    2005-01-01

    Approved for public release; distribution is unlimited This thesis argues that the Revolutionary Armed Forces of Colombia- Peopleâ s Army (FARC-EP), Latin Americaâ s oldest and most powerful guerrilla organization, has not abandoned its ideological beliefs and devolved into a criminal enterprise as a result of its immersion in the drug trade and participation in other illicit activities. Rather, the movement remains an ideologically committed, guerrilla insurgency whose strategic objecti...

  2. Building a democratic education. The Teacher Training College Model in times of revolutionary crisis (1974-1976)

    OpenAIRE

    Luís Mota; António Gomes Ferreira

    2015-01-01

    The present paper attempts to analyze the model and meaning of the reform of ordinary primary education, its ends and goals, and to address the ideological debate and clashes present in Teacher Training Colleges during the Ongoing Revolutionary Process (PREC). Experimental times of «pedagogical experiences», of the democratic construction of education, supported by a logic of equal opportunities and openness and intervention in the community, at a time when the educational system received the...

  3. MFDC - technological improvement in resistance welding controls

    International Nuclear Information System (INIS)

    Among the various Resistance Welding operations carried out in the production line of a fuel bundle end plug welding is the most critical operation. Welding controllers play a very vital role in obtaining consistent weld quality by regulating and controlling the weld current. Conventional mains synchronized welding controllers are at best capable of controlling the weld current at a maximum speed of the mains frequency. In view of the very short welding durations involved in the various stages of a fuel bundle fabrication, a need was felt for superior welding controllers. Medium Frequency Welding Controllers offer a solution to these limitations in addition to offering other advantages. Medium Frequency power sources offer precise welding current control as they regulate and correct the welding current faster, typically twenty times faster when operated at 1000Hz. An MFDC was employed on one of the welding machines and its performance was studied. This paper discusses about the various advantages of MFDCs with other controllers employed at NFC to end plug welding operation. (author)

  4. Welding for the CRBRP steam generators

    International Nuclear Information System (INIS)

    The rationale for selecting weld design, welding procedures and inspection methods was based upon the desire to obtain the highest reliability welds for the CRBRP steam generators. To assure the highest weld reliability, heavy emphasis was placed on the control of material cleanliness and composition substantially exceeding the requirements of the ASME Code for 2-1/4Cr-1Mo. The high tube/tubesheet weld quality was achieved through close material control, an extensive weld development program and the selection of high reliability welding equipment. A pre-production run involving 300 welds demonstrated the ability of the manufacturing team to work with the methods and tools provided during the development stage. Prior to the initiation of manufacturing, control of the process and equipment was demonstrated by a 52 weld qualification run. Shell and nozzle weld fabrication using TIG, MIG, and submerged arc procedures are also being controlled through precise specifications, including preheat and postheat programs, together with radiography and ultrasonic inspection to ascertain the weld quality desired. Details of the tube/tubesheet welding and shell welding are described and results from the weld testing program are discussed. (author)

  5. Current state of the art of mechanized welding of pipework

    International Nuclear Information System (INIS)

    The various chapters of this contribution deal with: (1) Mechanized welding of joints of pipes, bents and fittings (submerged arc welding; combination of submerged arc and TIG welding, TIG orbital welding, MIG/MAG welding). (2) Nozzle welding. (3) Internal tube welding-thermal sleeves. (4) Tube-in-tubeplate welding. The practical examples discussed cover a range of diameters between 4 and 800 mm, wall thickness between 1 and 60 mm, in austenitic or ferritic tube materials. (MM)

  6. «FREEDOM OF CONSCIENCE» AND «RELIGIOUS FREEDOM» IN THE UNDERSTANDING OF PRE-REVOLUTIONARY SCIENTISTS

    Directory of Open Access Journals (Sweden)

    Nadezhda Yuryevna Zagaynova

    2015-02-01

    Full Text Available The article considers approaches to the understanding of the concepts of «freedom of conscience» and «religious freedom» on the basis of the analysis of works of pre-revolutionary scientists. Allocated General and special traits defining these phenomena.The aim of this article is (based on the works of pre-revolutionary scientists to analyze ideas about the concept of freedom of conscience and religious liberty. Previously, scientists no attempt has been made to summarize the theoretical aspects of these categories, this is the novelty of the article.The research methodology consists dialectical view on the process of cognition of objective reality. They are implemented on the basis of a systematic approach. The article relies on the basic provisions of philosophy, theology and law.The research methods are universal, scientific and astronaute methods of cognition.In the study we can conclude that the pre-revolutionary scientists have not developed a unified approach with respect to such legal categories as «freedom of conscience and religious liberty».The results can be used in research work and in the educational process.

  7. ESTABLISHING SUSTAINABLE US HEV/PHEV MANUFACTURING BASE: STABILIZED LITHIUM METAL POWDER, ENABLING MATERIAL AND REVOLUTIONARY TECHNOLOGY FOR HIGH ENERGY LI-ION BATTERIES

    Energy Technology Data Exchange (ETDEWEB)

    Yakovleva, Marina

    2012-12-31

    FMC Lithium Division has successfully completed the project “Establishing Sustainable US PHEV/EV Manufacturing Base: Stabilized Lithium Metal Powder, Enabling Material and Revolutionary Technology for High Energy Li-ion Batteries”. The project included design, acquisition and process development for the production scale units to 1) produce stabilized lithium dispersions in oil medium, 2) to produce dry stabilized lithium metal powders, 3) to evaluate, design and acquire pilot-scale unit for alternative production technology to further decrease the cost, and 4) to demonstrate concepts for integrating SLMP technology into the Li- ion batteries to increase energy density. It is very difficult to satisfy safety, cost and performance requirements for the PHEV and EV applications. As the initial step in SLMP Technology introduction, industry can use commercially available LiMn2O4 or LiFePO4, for example, that are the only proven safer and cheaper lithium providing cathodes available on the market. Unfortunately, these cathodes alone are inferior to the energy density of the conventional LiCoO2 cathode and, even when paired with the advanced anode materials, such as silicon composite material, the resulting cell will still not meet the energy density requirements. We have demonstrated, however, if SLMP Technology is used to compensate for the irreversible capacity in the anode, the efficiency of the cathode utilization will be improved and the cost of the cell, based on the materials, will decrease.

  8. Laser welding of a tube

    International Nuclear Information System (INIS)

    For sleeving PWR steam generator tubes, the welding laser work is made under protection of a primary gas going out by the crossing window of the laser and under a secondary gas flowing axially through the head and the tube

  9. Welding process modelling and control

    Science.gov (United States)

    Romine, Peter L.; Adenwala, Jinen A.

    1993-01-01

    The research and analysis performed, and software developed, and hardware/software recommendations made during 1992 in development of the PC-based data acquisition system for support of Welding Process Modeling and Control is reported. A need was identified by the Metals Processing Branch of NASA Marshall Space Flight Center, for a mobile data aquisition and analysis system, customized for welding measurement and calibration. Several hardware configurations were evaluated and a PC-based system was chosen. The Welding Measurement System (WMS) is a dedicated instrument, strictly for the use of data aquisition and analysis. Although the WMS supports many of the functions associated with the process control, it is not the intention for this system to be used for welding process control.

  10. Welding and Production Metallurgy Facility

    Data.gov (United States)

    Federal Laboratory Consortium — This 6000 square foot facility represents the only welding laboratory of its kind within DA. It is capable of conducting investigations associated with solid state...

  11. Thermomechanical Modelling of Resistance Welding

    DEFF Research Database (Denmark)

    Bay, Niels; Zhang, Wenqi

    2007-01-01

    The present paper describes a generic programme for analysis, optimization and development of resistance spot and projection welding. The programme includes an electrical model determining electric current and voltage distribution as well as heat generation, a thermal model calculating heat...

  12. Laser welding of thermoplastic materials.

    Science.gov (United States)

    Chipperfield, F A; Jones, I A

    2001-06-01

    The capabilities of the three main types of laser are compared and a new technique is introduced, which laser welds plastics using an infrared absorber to create a joint that is almost invisible to the human eye. PMID:11488201

  13. APPLICATION OF SMALL PUNCH TESTS IN WELD CHARACTERIZATION

    Czech Academy of Sciences Publication Activity Database

    Milička, Karel; Sobotka, J.; Dobeš, Ferdinand; Kuboň, Z.

    Bratislava : Výskumný ústav zváračský Priemyselný inštitút SR, 2005, čl. 26. [Advanced Metallic Materials and Their Joining. Bratislava (SK), 25.10.2004-27.10.2004] R&D Projects: GA ČR GA106/03/1353 Institutional research plan: CEZ:AV0Z2041904 Keywords : creep * weld * small punch Subject RIV: JG - Metallurgy

  14. Ship hull plating weld misalignment effects when subjected to tension

    OpenAIRE

    Weaver, M. Cameron

    2001-01-01

    CIVINS Precision fabrication of ships is advancing. Welding is ubiquitous in ship construction and military standards have specified tolerances for joining plates in naval combatants. Precision manufacturing will allow the production of ships with smaller hull plate misalignments. A benefit from this could be improved ship survivability when subjected to underwater explosions. Slip Line Fracture Mechanics interacting with Finite Element Analysis (FEA) gives insight into the deformation, ne...

  15. Video Game Device Haptic Interface for Robotic Arc Welding

    Energy Technology Data Exchange (ETDEWEB)

    Corrie I. Nichol; Milos Manic

    2009-05-01

    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.

  16. Laser based spot weld characterization

    Science.gov (United States)

    Jonietz, Florian; Myrach, Philipp; Rethmeier, Michael; Suwala, Hubert; Ziegler, Mathias

    2016-02-01

    Spot welding is one of the most important joining technologies, especially in the automotive industry. Hitherto, the quality of spot welded joints is tested mainly by random destructive tests. A nondestructive testing technique offers the benefit of cost reduction of the testing procedure and optimization of the fabrication process, because every joint could be examined. This would lead to a reduced number of spot welded joints, as redundancies could be avoided. In the procedure described here, the spot welded joint between two zinc-coated steel sheets (HX340LAD+Z100MB or HC340LA+ZE 50/50) is heated optically on one side. Laser radiation and flash light are used as heat sources. The melted zone, the so called "weld nugget" provides the mechanical stability of the connection, but also constitutes a thermal bridge between the sheets. Due to the better thermal contact, the spot welded joint reveals a thermal behavior different from the surrounding material, where the heat transfer between the two sheets is much lower. The difference in the transient thermal behavior is measured with time resolved thermography. Hence, the size of the thermal contact between the two sheets is determined, which is directly correlated to the size of the weld nugget, indicating the quality of the spot weld. The method performs well in transmission with laser radiation and flash light. With laser radiation, it works even in reflection geometry, thus offering the possibility of testing with just one-sided accessibility. By using heating with collimated laser radiation, not only contact-free, but also remote testing is feasible. A further convenience compared to similar thermographic approaches is the applicability on bare steel sheets without any optical coating for emissivity correction. For this purpose, a proper way of emissivity correction was established.

  17. Welding of turbine rotor materials.

    OpenAIRE

    Richter, Tomáš

    2012-01-01

    In the Visual - Weld and Sysweld programs, a simplified simulation of the welding process of the turbine rotor made of 27NiCrMoV 15-6 substance was performed. The numerical analysis took place at the equal temperature of preheating and it covered both minimal and maximal percent chemical composition. The simulation proved that the percent deviations of elements in the substance change the speed necessary for reaching of the bainitic structure. Simulation results were verified by a practical e...

  18. Modelling of friction stir welding

    OpenAIRE

    Colegrove, Paul Andrew

    2004-01-01

    This thesis investigates the modelling of friction stir welding (FSW). FSW is a relatively new welding process where a rotating non-consumable tool is used to join two materials through high temperature deformation. The aim of the thesis is the development of a numerical model to improve process understanding and to assist in the design of new tools. The early part of the thesis describes the process, defines the modelling problem and describes why a computational fluid dynamics package (FLUE...

  19. Control of Robotic Welding Cell

    OpenAIRE

    Zabukovec, Andraž

    2013-01-01

    Industrial robots are common place in most modern manufacturing plants because the people running these factories are interested in reducing the plants’ dependence on a human workforce and to simultaneously improve productivity and quality. The thesis presents the operation of a robot welding cell project, which was developed at YASKAWA Ristro d.o.o. for the customer Akrapovič. The sub systems of the robot welding cell will be detailed in the thesis including the following topics; safety c...

  20. Robot automated EMPT sheet welding

    OpenAIRE

    Pasquale, Pablo; Schäfer, Ralph

    2012-01-01

    Many industrial applications require sheet to sheet or sheet to tube joints. The electromagnetic pulse technology is capable to produce these kinds of joints. In literature many examples of sheet to sheet solid state welding between similar and dissimilar metals are presented and analyzed in detail. However, the most of the presented welding applications, which are very focussed on the academic level, are simple specimens for example for tensile test. These specimens are usuall...

  1. Hybrid laser-TIG welding, laser beam welding and gas tungsten arc welding of AZ31B magnesium alloy

    International Nuclear Information System (INIS)

    Welding of AZ31B magnesium alloy was carried out using hybrid laser-TIG (LATIG) welding, laser beam welding (LBW) and gas tungsten arc (TIG) welding. The weldability and microstructure of magnesium AZ31B alloy welded using LATIG, LBW and TIG were investigated by OM and EMPA. The experimental results showed that the welding speed of LATIG was higher than that of TIG, which was caught up with LBW. Besides, the penetration of LATIG doubles that of TIG, and was four times that of LBW. In addition, arc stability was improved in hybrid of laser-TIG welding compared with using the TIG welding alone, especially at high welding speed and under low TIG current. It was found that the heat affect zone of joint was only observed in TIG welding, and the size of grains in it was evidently coarse. In fusion zone, the equiaxed grains exist, whose size was the smallest welded by LBW, and was the largest by TIG welding. It was also found that Mg concentration of the fusion zone was lower than that of the base one by EPMA in three welding processes

  2. Welding of Prosthetic Alloys

    Directory of Open Access Journals (Sweden)

    Wojciechowska M.

    2015-04-01

    Full Text Available This paper presents the techniques of joining metal denture elements, used in prosthetic dentistry: the traditional soldering technique with a gas burner and a new technique of welding with a laser beam; the aim of the study was to make a comparative assessment of the quality of the joints in view of the possibility of applying them in prosthetic structures. Fractographic examinations were conducted along with tensile strength and impact strength tests, and the quality of the joints was assessed compared to the solid metal. The experiments have shown that the metal elements used to make dentures, joined by the technique which employs a laser beam, have better strength properties than those achieved with a gas burner.

  3. Welding and reactor safety

    International Nuclear Information System (INIS)

    The high safety requirements which must be demanded of the quality of the welded joints in reactor technique have so far not been fulfilled in all cases. The errors occuring have caused considerable loss of availability and high material costs. They were not, however, so serious that one need have feared any immediate danger to the personnel or to the environment. The safety devices of reactor plants were only called upon in a few cases and to these they responded perfectly. The intensive efforts to complete and improve the specifications are to contribute to that in future, the reactor plants can be counted even more so as one of the safest technical plants ever. (orig./LH)

  4. Status and challenges of dissimilar metal welding

    OpenAIRE

    Simar, Aude; Jimenez Mena, Norberto; Avettand Fénoël, Marie-Noëlle; 10th International Friction Stir Welding Symposium

    2016-01-01

    A review of the status and current challenges of dissimilar metal welding is proposed. By dissimilar metal welding we mean the welding between metals of different primary chemical nature. The FSW scientific research community has been highly focussed on dissimilar metal welding in the past years as lightweighting is a major concern for the transportation (e.g. welding Al to steel, Al to Ti, Al to Mg, etc…) and electrical energy (e.g. welding Cu to Al) industry. Placing the right material at t...

  5. YAG laser welding with surface activating flux

    Institute of Scientific and Technical Information of China (English)

    樊丁; 张瑞华; 田中学; 中田一博; 牛尾诚夫

    2003-01-01

    YAG laser welding with surface activating flux has been investigated, and the influencing factors and mechanism are discussed. The results show that both surface activating flux and surface active element S have fantastic effects on the YAG laser weld shape, that is to obviously increase the weld penetration and D/W ratio in various welding conditions. The mechanism is thought to be the change of weld pool surface tension temperature coefficient, thus, the change of fluid flow pattern in weld pool due to the flux.

  6. Plastic flow pattern and its effect in friction stir welding of A2024 and A1060

    Institute of Scientific and Technical Information of China (English)

    WANG Xi-jing; ZHANG Zhong-ke; LI Jing; DA Chao-bing

    2006-01-01

    During the friction stir welding (FSW), the property of the welding joint is highly affected by the plastic and viscous flow behavior of the softened material. The flow pattern of the welded material was examined through observing the microstructural distribution of friction stir welded joints between dissimilar 2024 and 1060 aluminum alloy. The experimental results show that the flow patterns of material at different locations in the weld are different and can be divided into four layers along the thickness direction: surface flow layer influenced by the shoulder of the tool, in which the material tends to flow as integrity; horizontal flow layer influenced by the surface flow layer, in which the material of surface flow layer enters and flows forwards under the advancing force of the tool; vertical flow layer (plastic flow area induced by stirring of the pin), in which the flow pattern is complex and onion rings can often be observed; unstirred bottom layer because of the length of the pin being shorter than the thickness of the plates. The effect of plastic flow on welding quality was further investigated. The study suggests that welding quantity is significantly influenced by the flow pattern and defects always appear in horizontally lamellar flow region because of the complex flow pattern.

  7. Investigation on Mechanical Properties of 9%Cr/CrMoV Dissimilar Steels Welded Joint

    Science.gov (United States)

    Liu, Xia; Lu, Fenggui; Yang, Renjie; Wang, Peng; Xu, Xiaojin; Huo, Xin

    2015-04-01

    Advanced 9%Cr steel with good heat resistance and CrMoV with good toughness were chosen as candidate materials to fabricate combined rotor for steam turbine operating at over 620 °C. But the great difference in base metals properties presents a challenge in achieving sound defect-free joint with optimal properties in dissimilar welded rotor. In this paper, appropriate selection of filler metal, welding parameters, and post-weld heat treatment was combined to successfully weld 1100-mm-diameter 9%Cr/CrMoV dissimilar experimental rotor through ultra-narrow gap submerge arc welding. Some properties such as hardness, low-cycle fatigue (LCF), and high-cycle fatigue (HCF) combined with microstructural characterization qualify the integrity of the weld. Microstructural analysis indicated the presence of high-temperature tempered martensite as the phase responsible for the improved properties obtained in the weld. The Coffin-Manson parameters were obtained by fitting the data in LCF test, while the conditional fatigue strength was derived from the HCF test based on S-N curve. Analysis of hardness profile showed that the lowest value occurred at heat-affected zone adjacent to base metal which represents the appropriate location of fracture for the samples after LCF and HCF tests.

  8. Development of weld closure stations for plutonium long-term storage containers

    International Nuclear Information System (INIS)

    Weld closure stations for plutonium long-term storage containers have been designed, fabricated, and tested for the Advanced Recovery and Integrated Extraction System (ARIES) at the TA-55 Plutonium Facility of the Los Alamos National Laboratory. ARIES is a processing system used for the dismantlement of the plutonium pits from nuclear weapons. ARIES prepares the extracted-plutonium in a form which is compatible with long-term storage and disposition options and meets international inspection requirements. The processed plutonium is delivered to the canning module of the ARIES line, where it is packaged in a stainless steel container. This container is then packaged in a secondary container for long-term storage. Each of the containers is hermetically sealed with a full penetration weld closure that meets the requirements of the ASME Section IX Boiler and Pressure Vessel Code. Welding is performed with a gas tungsten arc process in an inert atmosphere of helium. The encapsulated helium in the nested containers allows for leak testing the weld closure and container. The storage package was designed to meet packaging requirements of DOE Standard 3013-96 for long-term storage of plutonium metal and oxides. Development of the process parameters, weld fixture, weld qualification, and the welding chambers is discussed in this paper

  9. FEM Analysis and Measurement of Residual Stress by Neutron Diffraction on the Dissimilar Overlay Weld Pipe

    International Nuclear Information System (INIS)

    Much research has been done to estimate the residual stress on a dissimilar metal weld. There are many methods to estimate the weld residual stress and FEM (Finite Element Method) is generally used due to the advantage of the parametric study. And the X-ray method and a Hole Drilling technique for an experimental method are also usually used. The aim of this paper is to develop the appropriate FEM model to estimate the residual stresses of the dissimilar overlay weld pipe. For this, firstly, the specimen of the dissimilar overlay weld pipe was manufactured. The SA 508 Gr3 nozzle, the SA 182 safe end and SA376 pipe were welded by the Alloy 182. And the overlay weld by the Alloy 52M was performed. The residual stress of this specimen was measured by using the Neutron Diffraction device in the HANARO (High-flux Advanced Neutron Application ReactOr) research reactor, KAERI (Korea Atomic Energy Research Institute). Secondly, FEM Model on the dissimilar overlay weld pipe was made and analyzed by the ABAQUS Code (ABAQUS, 2004). Thermal analysis and stress analysis were performed, and the residual stress was calculated. Thirdly, the results of the FEM analysis were compared with those of the experimental methods

  10. About the Modern Historiography of the Pre-Revolutionary Period of Kiev Polytechnic Institute

    Directory of Open Access Journals (Sweden)

    M. Stepanova

    2016-02-01

    Full Text Available In this paper the problem of coverage of the Kiev Polytechnic Institute in prerevolutionary period in the recent period historiography. The problem of the origin and highlight the main achievements of the technical staff of the Kiev Polytechnic Institute in pre-revolutionary period shown on the basis of documentary and sources, works of a general nature. It is noted that in the recent period, new topics related to the initial period of the university. In these publications indicate veloped and implemented technical professions to implement the latest developments unknown at the time fields of science. 1991–2015 is a significant revival of interest in the history Kyiv Politechnical Institute in 1898–1917. This is reflected in the increasing number of scientific papers, including master’s and doctoral dissertations on subjects of this kind, so devoted to the problems of conducting scientific conferences, publication of special scientific collections. This is largely explained by the change in historical research priorities when much more attention than in the previous period were paid ideological processes, the study of cultural background, man. The elimination of ideological and political constraints contributed to a wide range of views on issues of university history, contributed to «nationalization of history» — the fragmentation ever joint historical — cultural space. Among the signs of the times — the revival of journalism familiar to us from the late nineteenth — early twentieth century the conservative image of the university KPI. Some publicistic, which now can be found in the writings in general does not define the characteristics of the period. Innovations time also cause problems setting features a «national model» university that requires a deeper study of the relationship between the university and society. Accordingly, researchers have begun more attention to internal factors of the КPI, although today it is not

  11. Laser Welding in Electronic Packaging

    Science.gov (United States)

    2000-01-01

    The laser has proven its worth in numerous high reliability electronic packaging applications ranging from medical to missile electronics. In particular, the pulsed YAG laser is an extremely flexible and versatile too] capable of hermetically sealing microelectronics packages containing sensitive components without damaging them. This paper presents an overview of details that must be considered for successful use of laser welding when addressing electronic package sealing. These include; metallurgical considerations such as alloy and plating selection, weld joint configuration, design of optics, use of protective gases and control of thermal distortions. The primary limitations on use of laser welding electronic for packaging applications are economic ones. The laser itself is a relatively costly device when compared to competing welding equipment. Further, the cost of consumables and repairs can be significant. These facts have relegated laser welding to use only where it presents a distinct quality or reliability advantages over other techniques of electronic package sealing. Because of the unique noncontact and low heat inputs characteristics of laser welding, it is an ideal candidate for sealing electronic packages containing MEMS devices (microelectromechanical systems). This paper addresses how the unique advantages of the pulsed YAG laser can be used to simplify MEMS packaging and deliver a product of improved quality.

  12. Origin and significance of defects in welds

    International Nuclear Information System (INIS)

    In the past 10 to 15 years significant advances have taken place in the understanding of the origin and nature of weld discontinuities. The furthering of the knowledge of hot cracking, cold cracking, lamellar tearing and porosity formation is due to the development and utilization of sophisticated techniques for microscopy and microanalysis and the concerted efforts of many researchers in the U.S. and abroad. Concurrent with the progress toward better definition of the metallurgical mechanisms for discontinuity formation, the development of the fracture mechanics approach for the assessment of the significance of the discontinuities was brought into focus. It is the marriage of the metallurgical understanding of formation and the mechanics assessment of relevance that permits discontinuities to be treated with a new degree of sophistication. The many types of cracking and porosity formation were the subjects of numerous studies in the intervening years. This presentation will treat the various types of weld discontinuities which have their origin closely related to a metallurgical mechanism. Emphasis will be placed on hot cracking, and porosity formation with information presented on cold cracking, reheat cracking and lamellar tearing. The employment of the newer metallurgical tools will be discussed in terms of their utilization in determining the cause of discontinuity formation

  13. Experimental study on activating welding for aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    Huang Yong; Fan Ding

    2005-01-01

    TIG welding and EB welding for aluminum alloy 3003 were carried out to study the effects of activating flux on weld penetration of activating welding for aluminum alloys. SiO2 was used as the activating flux. It is found that, SiO2 can increase the weld penetration and decrease the weld width of FBTIG when the flux gap is small. For A-TIG welding and EB welding with focused mode, the weld penetrations and the weld widths increase simultaneously. SiO2 has little effect on the weld penetration and weld width of EB welding with defocused mode. It is believed that, change of surface tension temperature gradient is not the main mechanism of SiO2 improving weld penetration of activating welding for aluminum alloys.

  14. A comparison of the physics of Gas Tungsten Arc Welding (GTAW), Electron Beam Welding (EBW), and Laser Beam Welding (LBW)

    Science.gov (United States)

    Nunes, A. C., Jr.

    1985-01-01

    The physics governing the applicability and limitations of gas tungsten arc (GTA), electron beam (EB), and laser beam (LB) welding are compared. An appendix on the selection of laser welding systems is included.

  15. The effect of post-welding conditions in friction stir welds: From weld simulation to Ductile Failure

    DEFF Research Database (Denmark)

    Hattel, Jesper Henri; Nielsen, Kim Lau; Tutum, Cem Celal

    2012-01-01

    possible effect of the post-welding conditions when subjecting a friction stir weld to loading transverse to the weld line. The numerical model of the friction stir welded joint, employs a step-wise modeling approach to combine an in-situ weld simulation with a post-welding failure analysis. Using the...... commercial software ANSYS, a thermo-mechanical model is employed to predict the thermally induced stresses and strains during welding, while an in-house finite element code is used to study the plastic flow localization and failure in a subsequent structural analysis. The coupling between the two models is...... prior to plastic flow localization was observed, with a substantial influence on the specimen elongation at the onset of localization and thereby failure. This influence is, however, shown to be strongly affected by the applied boundary conditions. Specimens cut from the welded plate, transverse to the...

  16. Laser spot welding of electronic micro parts

    Science.gov (United States)

    Ostendorf, Andreas; Temme, Thorsten; Zeadan, Jeihad

    2004-10-01

    This paper deals with parameter optimization and online monitoring of laser spot welding (LSW). Using Nd:YAG laser, a wide range of experiments regarding the welding process have been carried out for both successful and failed welds. The typical failures appearing during packaging of surface mounted devices (SMDs) on flexible printed circuits (FPC) include gaps, a loss of connection between the welded components, and damage of the printed circuit boards. A flip-flop device called SO16 and lead frames as two components of widely used SMDs were packaged on FPCs in the experiments. The reproducibility of the weld quality for SO16 (FeNi) is greater than for lead frames (CuFe2P); this points out the difficulties appearing during copper or copper alloy welding. However, a correlation between the weld quality and the detected emission signals recorded during the weld process has been found for both components. The detected signals of the optical process emission for successful welds depict identical characterisics which are divided into three relevant signal phases. Changes in the signal characteristics, especially in these phases, imply information about the weld quality. While monitoring the welding processes for both components are possible, the detected signals for SO16 are less sensitive to process variations compared to those for lead frames. Based on spectral analysis, the intensity of the detected emission due to SO16 welding is slightly higher than the intensity due to lead frames welding.

  17. Comparative study on CO2 laser overlap welding and resistance spot welding for galvanized steel

    International Nuclear Information System (INIS)

    Highlights: ► Laser welding and resistance welding are respectively researched on galvanized steel. ► The characteristics of the two kinds of welding methods are systematically analyzed. ► Laser welding joint have much more compact structures and smaller heat-affected zones. ► The tensile-shear performance of laser weld joint is superior under certain condition. ► Laser welding test pieces has greater resistance to deformation and corrosion. -- Abstract: The CO2 laser overlap welding and the resistance spot welding are respectively investigated on DC56D galvanized steel used for auto body. The characteristics of the two types of welding methods are systematically analyzed in terms of the weld molding, tensile-shear performance, microstructure, hardness, and corrosion resistance of welding joint. The results show that, the fusion widths of the upper and lower surface are almost the same for the resistance welding joint, and the weld nugget is surrounded by the heat-affected zone. While the laser welding joint belongs to deep penetration welding, the weld fusion width presents wide at the top and narrow at the bottom, and the heat-affected zone is situated on both sides of the weld pool. Compared with resistance spot welding joint, laser welding joints have much more ultrafine microstructures, much smaller heat-affected zones, as well as greater resistance to deformation and corrosion. In addition, the tensile-shear performance of laser weld joints is superior to that of resistance welding joints under certain conditions.

  18. Development of technique for laser welding of biological tissues using laser welding device and nanocomposite solder.

    Science.gov (United States)

    Gerasimenko, A; Ichcitidze, L; Podgaetsky, V; Ryabkin, D; Pyankov, E; Saveliev, M; Selishchev, S

    2015-08-01

    The laser device for welding of biological tissues has been developed involving quality control and temperature stabilization of weld seam. Laser nanocomposite solder applied onto a wound to be weld has been used. Physicochemical properties of the nanocomposite solder have been elucidated. The nature of the tissue-organizing nanoscaffold has been analyzed at the site of biotissue welding. PMID:26738200

  19. ALGORITHM AND IMPLEMENTATION OF AUTO-SEARCHING WELD LINE FOR WELDING MOBILE ROBOT

    Institute of Scientific and Technical Information of China (English)

    ZHANG Ke; L(U) Xueqin; WU Yixiong; LOU Songnian

    2006-01-01

    An algorithm of auto-searching weld line for welding mobile robot is presented.Auto-searching weld line is that the robot can automatically recognize a weld groove according to the characteristics of the weld groove before welding, and then adjust itself posture to the desired status preparing for welding, namely, it is a process that the robot autonomously aligns itself to the center of welding seam. Firstly, the configuration of welding mobile robot with the function of auto-searching weld line is introduced, then the algorithm and implementation of auto-searching weld line are presented on the basis of kinematics model of the robot, at last trajectory planning among auto-searching weld line is investigated in detail. The experiment result shows that the developed welding mobile robot can successfully implement the task of auto-searching weld line before welding, tracking error precision can be controlled to approximate ± 1.5 mm, and satisfy the requirement of practical welding project.

  20. An initial study on welding procedure using tandem MIG welding of high strength aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    林三宝; 刚铁; 杨春利; 崔洪波

    2004-01-01

    The high-speed camera system and data acquisition system of welding parameters were created in tandem MIG welding of high strength aluminum alloy. The experiments were carried out in order to obtain the photos of droplet transfer under different welding parameters in pulsed mode. The droplet transfer mode of "one pulse one droplet" becomes the preferred selection during welding process because of its stable procedure and sound weld form. The parameter ranges for corresponding transfer mode were experimentally achieved, among which the stable droplet transfer mode of "one pulse one droplet" can be realized. These efforts brave the way for control weld heat input and weld formation in the future.

  1. Diffusion welding in air. [solid state welding of butt joint by fusion welding, surface cleaning, and heating

    Science.gov (United States)

    Moore, T. J.; Holko, K. H. (Inventor)

    1974-01-01

    Solid state welding a butt joint by fusion welding the peripheral surfaces to form a seal is described along with, autogenetically cleaning the faying or mating surfaces of the joint by heating the abutting surfaces to 1,200 C and heating to the diffusion welding temperature in air.

  2. Effect of Laser Welding Parameters on Formation of NiTi Shape Memory Alloy Welds

    Directory of Open Access Journals (Sweden)

    Wei Wang

    2014-01-01

    Full Text Available In this work experimental trials of welding of NiTi flat plates with 2.0 mm thickness were conducted using a 4.5 kW continuous wave (CW Nd:YAG laser. The influences of laser output power, welding speed, defocus amount and side-blow shielding gas flow rate on the morphology, welding depth and width, and quality of the welded seam were investigated. Meanwhile, the effects of heat input on the mechanical and functional properties of welded joints were studied. The results show that laser welding can take better formation in NiTi alloys. The matching curves with laser power and welding speed affecting different formation of welds were experimentally acquired, which can provide references for laser welding and engineering application of NiTi alloy. The heat input has obvious effects on the ultimate tensile strength (UTS and shape memory behavior of the welded joints.

  3. Effect of weld reinforcement on axial plastic buckling of welded steel cylindrical shells

    Institute of Scientific and Technical Information of China (English)

    Chu-lin YU; Zhi-ping CHEN; Ji WANG; Shun-juan YAN; Li-cai YANG

    2012-01-01

    The effect of weld reinforcement on axial plastic buckling of welded steel cylindrical shells is investigated through experimental and numerical buckling analysis using six welded steel cylindrical shell specimens.The relationship between the amplitude of weld reinforcement and the axial plastic buckling critical load is explored.The effect of the material yield strength and the number of circumferential welds on the axial plastic buckling is studied.Results show that circumferential weld reinforcement represents a severe imperfect form of axially compressed welded steel cylindrical shells and the axial plastic buckling critical load decreases with the increment of the mean amplitude of circumferential weld reinforcement.The material yield strength and the number of circumferential welds are found to have no significant effect on buckling waveforms; however,the axial plastic buckling critical load can be decreased to some extent with the increase of the number of circumferential welds.

  4. Predicting effects of diffusion welding parameters on welded joint properties by artificial neural network

    Institute of Scientific and Technical Information of China (English)

    刘黎明; 祝美丽; 牛济泰; 张忠典

    2001-01-01

    The static model for metal matrix composites in diffusion welding was established by means of artificial neural network method. The model presents the relationship between weld joint properties and welding parameters such as welding temperature, welding pressure and welding time. Through simulating the diffusion welding process of SiCw/6061Al composite, the effects of welding parameters on the strength of welded joint was studied and optimal technical parameters was obtained. It is proved that this method has good fault-tolerant ability and versatility and can overcome the shortage of the general experiment. The established static model is in good agreement with the actual welding process, so it becomes a new path for studying the weldability of new material.

  5. Online Visual Quality Inspection for Weld Seams

    Science.gov (United States)

    Löhndorf, Maike; Ramoser, Herbert; Cambrini, Luigi

    2007-12-01

    Arc welding is a widely used technology in almost all sectors of industrial production. Many tasks are automatically performed by robots. This paper presents a flexible vision based quality management system to detect defects online during the weld process.

  6. Method and instrument for judging welded joints

    International Nuclear Information System (INIS)

    This non-destructive method works in real time and evaluates the mechanical stress waves going out from the weld. The invention is described using a laser welding instrument as an example. (RW) 891 RW/RW 892 MKO

  7. 49 CFR 192.225 - Welding procedures.

    Science.gov (United States)

    2010-10-01

    ... qualified under section 5 of API 1104 (incorporated by reference, see § 192.7) or section IX of the ASME... § 192.7) to produce welds meeting the requirements of this subpart. The quality of the test welds...

  8. 49 CFR 195.214 - Welding procedures.

    Science.gov (United States)

    2010-10-01

    ... accordance with welding procedures qualified under Section 5 of API 1104 or Section IX of the ASME Boiler and Pressure Vessel Code (incorporated by reference, see § 195.3) . The quality of the test welds used...

  9. Automatic monitoring of vibration welding equipment

    Energy Technology Data Exchange (ETDEWEB)

    Spicer, John Patrick; Chakraborty, Debejyo; Wincek, Michael Anthony; Wang, Hui; Abell, Jeffrey A; Bracey, Jennifer; Cai, Wayne W

    2014-10-14

    A vibration welding system includes vibration welding equipment having a welding horn and anvil, a host device, a check station, and a robot. The robot moves the horn and anvil via an arm to the check station. Sensors, e.g., temperature sensors, are positioned with respect to the welding equipment. Additional sensors are positioned with respect to the check station, including a pressure-sensitive array. The host device, which monitors a condition of the welding equipment, measures signals via the sensors positioned with respect to the welding equipment when the horn is actively forming a weld. The robot moves the horn and anvil to the check station, activates the check station sensors at the check station, and determines a condition of the welding equipment by processing the received signals. Acoustic, force, temperature, displacement, amplitude, and/or attitude/gyroscopic sensors may be used.

  10. Recent developments in underwater repair welding

    International Nuclear Information System (INIS)

    As nuclear plants age and reactor internal components begin to show increased evidence of age-related phenomena such as corrosion and fatigue, interest in the development of cost-effective mitigation and repair remedies grows. One technology currently receiving greater development and application program focus is underwater welding. Underwater welding, as used herein, is the application of weld metal to a substrate surface that is wet, but locally dry in the immediate area surrounding the welding torch. The locally dry environment is achieved by the use of a mechanical device that is specifically designed for water exclusion from the welding torch, surface to be welded, and the welding groove. This paper will explore recent developments in the use of underwater welding as a mitigation and repair technique. (author)

  11. Alloy 800 welding experience at UKAEA Springfields

    International Nuclear Information System (INIS)

    Investigatins into the welding of alloy 800 at the Reactor Fuel Element Laboratories, Springfields, commenced about three years ago following an extended development programme on tube to tube plate welding of low alloy and stainless steels for the Prototype Fast Reactor. The techniques and approach developed for critical fuel element welding applications had proved equally suitable for the precision welding requirements on the much heavier sections of heat exchangers. It had been demonstrated that the same control of weld quality and profile could be achieved with consistency and the permissible range of critical parameters could be readily defined. Because of this, development work was continued to include other materials, such as alloy 800, which might be of potential use. The tungsten inert gas (T.I.G.) arc welding process is used, and the equipment, including the control system, is described. Tube to tube-plate welding, and tube to tube butt welding, are discussed. (author)

  12. Novel characterization of welding fumes

    International Nuclear Information System (INIS)

    Complete text of publication follows. The lung deposition of welding fume comprised of a large number of primary nanoparticles, occurs predominantly in the alveolar region. The particle size distribution of welding fumes is an important factor determining the bioaccessibility of metal components and the hazard potential of pro-inflammatory effects driven largely by soluble and insoluble transition metals. Several techniques are frequently used for determining the particle size distribution of different welding fumes. A scanning mobility particle sizer (SMPS) offers the opportunity of temporal particle-size distribution measurements and to follow the changes in particle number concentration, a transmission electron microscope (TEM) is capable of visualizing the individual particle morphology and measuring the particle size of primary particles. Are the results obtained with these two techniques comparable? To answer this question welding fumes were generated by different welding methods and examined by a SMPS in the range of 10 to 487 nanometers. The SMPS instrument measures the size distribution of fine particles by separating particles based on electrical-mobility. Particles of a selected size are detected optically, using a detection technology in which small particle visibility is enhanced by growing the particles in a condensing butyl alcohol vapour. Samples were collected on TEM grids made of nickel, copper and silicon for primary particle characterization by TEM. Particle size distributions with both analytical techniques were determined. The most obvious features of the TEM analysis were that the primary welding fume particles had a tendency to form chainlike agglomerates in case of all welding, and almost no individual primary particles were found. It is quite unclear how these agglomerates are detected by the SMPS. An important finding of the chemical analysis of the particles by TEM was that the larger particles contained cores of more volatile components

  13. Automatic classification of defects in weld pipe

    International Nuclear Information System (INIS)

    With the advancement of computer imaging technology, the image on hard radiographic film can be digitized and stored in a computer and the manual process of defect recognition and classification may be replace by the computer. In this paper a computerized method for automatic detection and classification of common defects in film radiography of weld pipe is described. The detection and classification processes consist of automatic selection of interest area on the image and then classify common defects using image processing and special algorithms. Analysis of the attributes of each defect such as area, size, shape and orientation are carried out by the feature analysis process. These attributes reveal the type of each defect. These methods of defect classification result in high success rate. Our experience showed that sharp film images produced better results

  14. Thermal treatment of dissimilar steels' welded joints

    Science.gov (United States)

    Nikulina, A. A.; Denisova, A. S.; Gradusov, I. N.; Ryabinkina, P. A.; Rushkovets, M. V.

    2016-04-01

    In this paper combinations of chrome-nickel steel and high-carbon steel, produced by flash butt welding after heat treatment, are investigated. Light and electron microscopic studies show that the welded joints after heat treatment have a complex structure consisting of several phases as initial welded joints. A martensite structure in welded joints after thermal treatment at 300... 800 °C has been found.

  15. Welding of high manganese- and carbon steels

    International Nuclear Information System (INIS)

    Technology and conditions of welding of high manganese and carbon steel by a resistance welding technique using an intermediate part are developed. Austenitic chromium-nickel 12Kh18N10T steel is chosen as a material of the intermediate part. The recommended welding conditions insure a high quality of the weld joint in terms of metal structure and its mechanical properties. It is the basic metal of the joint that fractures under mechanical testing

  16. Managing distortion in welded structures using FEM

    OpenAIRE

    Ghanadi, Mehdi

    2013-01-01

    Welding as high productive joining method is widely employed in automotive, aerospace and shipbuilding industries. In practice, welding distortion brings about undesirable effects on production accuracy, appearance and strength of welded components. Thus, in order to increase the productivity and decrease the cost of the product, prediction and analysis of welding deformation are key factors in industrial context. Distortion of a structure can be measured experimentally; whilst in case of lar...

  17. Qualification of electron beam welding procedure

    International Nuclear Information System (INIS)

    In electron beam welding, the problem of the procedure qualification is quite special. The main results obtained are presented namely: the influence of the welding equipment used, the finding of significant testing to be taken into consideration for the process qualification. The experiments have been made using two different welding machines. Two materials have been selected (austenitic stainless steel and ferritic steel) and two welding positions (flat position and horizontal-vertical position) investigated

  18. Bronchial reactions to exposure to welding fumes.

    OpenAIRE

    Contreras, G R; Chan-Yeung, M.

    1997-01-01

    OBJECTIVES: To study the airway response and its mechanism to welding fumes in six welders with respiratory symptoms. METHODS: Methacholine and welding challenge tests were carried out. The concentration of welding fumes during the exposure test was measured. On two subjects who developed bronchoconstricition to welding challenge, additional tests were carried out including prick, patch, and inhalation challenges with metal salt solutions. RESULTS: Three subjects developed immediate bronchial...

  19. Experimental determination of the weld penetration evolution in keyhole plasma arc welding

    Institute of Scientific and Technical Information of China (English)

    Hu Qingxian; Wu Chuansong; Zhang Yuming

    2007-01-01

    Keyhole plasma arc welding experiments are conducted to measure the weld geometry and penetration at different moments during the initial phase from igniting arc to quasi-steady state. Indirect information on keyhole formation and evolution in plasma arc welding can be extracted based on the weld macrophotograph at cross section. It has laid foundation to verify the mathematical models of keyhole plasma arc welding.

  20. Prospect of Friction Stir Welding in Automobile TWB Production as Alternative of Laser Welding

    OpenAIRE

    Shahriyar, Mohammed Hasan

    2012-01-01

    In some situation, commonly used welding processes (Laser and Seam welding) in car industry do not produce mechanically acceptable Tailor Welded Blanks (TWB). The present work explores whether the Friction Stir welding (FSW) can overcome three major drawbacks of Laser welding process to produce TWB for car industry. It is identified that some types of Aluminum to Aluminum joints, some combinations of High Strength Steels (HSS) to HSS joints and Steel to Aluminum joints are troublesome to prod...