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Sample records for arc welding dynamic

  1. Dynamic character analysis for the arc welding power source based on fuzzy logic

    Institute of Scientific and Technical Information of China (English)

    Wang Zhenmin; Xue Jiaxiang; Wang Fuguang

    2007-01-01

    A lot of experimental methods have been brought forth to assess the dynamic character of the arc welding power source, but up to now, this issue has not been solved very well. In this paper, based on the fuzzy logic reasoning method, a dynamic character assessing model for the arc welding power source was established and used to analyze the dynamic character of the welding power source. Three different types of welding machine have been tested, and the characteristic information of the electrical signals such as re-striking arc voltage, low welding current and so on of the welding process were extracted accurately by using a self-developed welding dynamic arc wavelet analyzer. The experimental results indicate that this model can be used as a new assessing method for the dynamic character of the arc welding power source.

  2. An analysis of the dynamic resistance and the instantaneous energy of the CO2 arc welding process

    Institute of Scientific and Technical Information of China (English)

    Wang Zhenmin; Xue Jiaxiang; Dong Fei; Yang Guohua; Lu Xiaoming

    2007-01-01

    A self-developed welding dynamic arc wavelet analyzer was adopted to analyze and assess the welding process of two CO2 arc welding machines. The experimental results indicate that the instantaneous energy can reflect the influence of the welding current and voltage on dynamic arc characteristic synthetically. Through calculating and analyzing the instantaneous energy, the energy during arc ignition and short circuit in CO2 welding process can be confirmed rationally, thus the foundation for the accurate design and control of the welding current and voltage can be provided. By reducing the ripple disturbance of the dynamic resistance, avoiding peak current and voltage waveform,and enhancing the transition frequency of short circuit suitably, the stability of the welding arc and the weld appearance can be improved.

  3. 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)

  4. Application of welding science to welding engineering: A lumped parameter gas metal arc welding dynamic process model

    Energy Technology Data Exchange (ETDEWEB)

    Murray, P.E.; Smartt, H.B.; Johnson, J.A. [Lockheed Martin Idaho Technologies, Idaho Falls, ID (United States)

    1997-12-31

    We develop a model of the depth of penetration of the weld pool in gas metal arc welding (GMAW) which demonstrates interaction between the arc, filler wire and weld pool. This model is motivated by the observations of Essers and Walter which suggest a relationship between droplet momentum and penetration depth. A model of gas metal arc welding was augmented to include an improved model of mass transfer and a simple model of accelerating droplets in a plasma jet to obtain the mass and momentum of impinging droplets. The force of the droplets and depth of penetration is correlated by a dimensionless linear relation used to predict weld pool depth for a range of values of arc power and contact tip to workpiece distance. Model accuracy is examined by comparing theoretical predictions and experimental measurements of the pool depth obtained from bead on plate welds of carbon steel in an argon rich shielding gas. Moreover, theoretical predictions of pool depth are compared to the results obtained from the heat conduction model due to Christensen et al. which suggest that in some cases the momentum of impinging droplets is a better indicator of the depth of the weld pool and the presence of a deep, narrow penetration.

  5. 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.

  6. 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...

  7. Arc Interference Behavior during Twin Wire Gas Metal Arc Welding Process

    Directory of Open Access Journals (Sweden)

    Dingjian Ye

    2013-01-01

    Full Text Available In order to study arc interference behavior during twin wire gas metal arc welding process, the synchronous acquisition system has been established to acquire instantaneous information of arc profile including dynamic arc length variation as well as relative voltage and current signals. The results show that after trailing arc (T-arc is added to the middle arc (M-arc in a stable welding process, the current of M arc remains unchanged while the agitation increases; the voltage of M arc has an obvious increase; the shape of M arc changes, with increasing width, length, and area; the transfer frequency of M arc droplet increases and the droplet itself becomes smaller. The wire extension length of twin arc turns out to be shorter than that of single arc welding.

  8. An approach for optimizing arc welding applications

    International Nuclear Information System (INIS)

    The dynamic and transport mechanisms involved in the arc plasma and the weld pool of arc welding operations are numerous and strongly coupled. They produce a medium the magnitudes of which exhibit rapid time variations and very marked gradients which make any experimental analysis complex in this disrupted environment. In this work, we study the TIG and MIG processes. An experimental platform was developed to allow synchronized measurement of various physical quantities associated with welding (process parameters, temperatures, clamping forces, metal transfer, etc.). Numerical libraries dedicated to applied studies in arc welding are developed. They enable the treatment of a large flow of data (signals, images) with a systematic and global method. The advantages of this approach for the enrichment of numerical simulation and arc process control are shown in different situations. Finally, this experimental approach is used in the context of the chosen application to obtain rich measurements to describe the dynamic behavior of the weld pool in P-GMAW. Dimensional analysis of these experimental measurements allows to identify the predominant mechanisms involved and to determine experimentally the characteristic times associated. This type of approach includes better description of the behavior of a macro-drop of molten metal or the phenomena occurring in the humping instabilities. (author)

  9. 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.

  10. 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.

  11. Sensor Control of Robot Arc Welding

    Science.gov (United States)

    Sias, F. R., Jr.

    1983-01-01

    The potential for using computer vision as sensory feedback for robot gas-tungsten arc welding is investigated. The basic parameters that must be controlled while directing the movement of an arc welding torch are defined. The actions of a human welder are examined to aid in determining the sensory information that would permit a robot to make reproducible high strength welds. Special constraints imposed by both robot hardware and software are considered. Several sensory modalities that would potentially improve weld quality are examined. Special emphasis is directed to the use of computer vision for controlling gas-tungsten arc welding. Vendors of available automated seam tracking arc welding systems and of computer vision systems are surveyed. An assessment is made of the state of the art and the problems that must be solved in order to apply computer vision to robot controlled arc welding on the Space Shuttle Main Engine.

  12. Modeling of Arc Force in Plasma Arc Welding

    Institute of Scientific and Technical Information of China (English)

    GAO Zhonglin; HU Shengsun; YIN Fengliang; WANG Rui

    2008-01-01

    A three. dimensional mathematical model for the transferred-type argon arc was developed to describe arc force on the anode surface. The software ANSYS was employed to solve the model. The model includes a part of torch and tungsten electrode to achieve m ore reasonable results. The arc temperature and flow fields were derived. And the influences of welding parameters on arc force were also studied. The simulated results show that arc pressure at the anode are dependent on the welding current, plasma gas flow rate and electrode neck-in, while not sensitive to arc length.

  13. 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...

  14. 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

  15. Hybrid Laser-Arc Welding Tanks Steels

    Science.gov (United States)

    Turichin, G.; Tsibulskiy, I.; Kuznetsov, M.; Akhmetov, A.; Klimova-Korsmik, O.

    2016-04-01

    The results investigate hybrid laser-arc welding of high strength steels using design responsible metallic construction and the highest strength body of vehicles. Welds from modern high strength steels grade Hardox 400, Hardox 450, Armox 600T and AB were created. High power fiber laser LS-15 with output 15 kW and arc rectifier VDU - 1500 DC were used in the experiment. Results of the metallographic research and mechanical tests are presented.

  16. 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…

  17. ARC length control for plasma welding

    Science.gov (United States)

    Iceland, William F. (Inventor)

    1988-01-01

    A control system to be used with a plasma arc welding apparatus is disclosed. The plasma arc welding apparatus includes a plasma arc power supply, a contactor, and an electrode assembly for moving the electrode relative to a work piece. The electrode assembly is raised or lowered by a drive motor. The present apparatus includes a plasma arc adapter connected across the power supply to measure the voltage across the plasma arc. The plasma arc adapter forms a dc output signal input to a differential amplifier. A second input is defined by an adjustable resistor connected to a dc voltage supply to permit operator control. The differential amplifier forms an output difference signal provided to an adder circuit. The adder circuit then connects with a power amplifier which forms the driving signal for the motor. In addition, the motor connects to a tachometor which forms a feedback signal delivered to the adder to provide damping, therby avoiding servo loop overshoot.

  18. Arc pressure control in GTA welding

    International Nuclear Information System (INIS)

    Relationships are established between the peak current of a pulsed, rectangular current waveform and the pulse current duty cycle under conditions of constant arc power. By appropriate choice of these interrelated parameters, it is shown that the arc pressure may be varied over a wide range even though the arc power is held constant. The methodology is suggested as a means of countering the effect of gravity in 5-G welding, while maintaining constant heat input to the weld. Combined with appropriate penetration sensors, the methodology is additionally suggested as a means of controlling penetration

  19. Exploiting robots in arc welded fabrication

    International Nuclear Information System (INIS)

    This book explores the use of robots for industrial arc welding applications. A number of important issues, such as safety and economics are addressed. A wide range of industrial installation applications are described including production line chassis welding with multiple robots. The use of vision based sensor systems is explained to provide data on joint location and joint volume. Other areas covered include flexible manufacturing systems, computer integrated manufacture and design problems. The book concludes with a review of future trends. (UK)

  20. A study on consumable aided tungsten indirect arc welding

    Institute of Scientific and Technical Information of China (English)

    Wang Jun; Wang Yuxin; Feng Jicai

    2009-01-01

    A consumable aided tungsten indirect arc welding method has been studied. This method is different from the traditional TIG welding because it introduces an MIG welding torch into the traditional TIG welding system. An indirect arc is generated between the consumable electrode of the MIG welding torch and the tungsten electrode of the TIG welding torch, but not generated between the tungsten electrode of the welding torch and the base metal. Welding current flows from the consumable electrode to the tungsten electrode in the free-burning indirect arc. The consumable aided tungsten indirect arc welding not only rapidly melts the welding wire but also effectively restrains the excessive fusion of the base metal. The welding experiment and the theoretical analysis confirm that this method can obtain a high deposition rate and a low dilution ratio during the welding process.

  1. What makes an electric welding arc perform its required function

    Energy Technology Data Exchange (ETDEWEB)

    Correy, T.B.

    1982-09-01

    The physics of direct current and alternating current welding arcs, the heat transfer of direct current welding arcs, the characteristics of dc welding and ac welding power supplies and recommendations for the procurement and maintenance of precision power supplies are discussed. (LCL)

  2. 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.

  3. Modelling of GMA welding in short-arc mode

    International Nuclear Information System (INIS)

    Nowadays there is a lot of welding processes giving an answer to the great diversity of joints to realize and to the characteristics of the metals employed. The first chapter describes the different power sources used in welding. After that, a more detailed explanation of arc welding is given. Finally we present the design of a welding test bed. One can, of course, use an empirical approach to optimize a process. Nevertheless there are advantages in choosing an analytical approach since we can expect significant progress in the understanding of the dynamical interactions in the arc. That's why we present in the second chapter the theoretical knowledge concerning the behaviour of the molten metal transferred during Gas Metal Arc Welding. This work involves as well an experimental aspect required for the elaboration of the databases used to build the model. The recordings were made at CTAS on a test bed equipped with an acquisition system for measuring voltage, current, wire feed speed and high speed videos. The third chapter presents our research of a segmentation method to measure some relevant quantities. We propose a software sensor based on the active contour theory and we show good results on experimental movies. An adjustment step of the model is needed and described in the fourth chapter. The created simulator allows us to interpret some important phenomena in welding, to make a sensitive study 'without risk' and to give theoretical defect signatures. (author)

  4. Numerical modelling of steel arc welding

    International Nuclear Information System (INIS)

    Welding is a highly used assembly technique. Welding simulation software would give access to residual stresses and information about the weld's microstructure, in order to evaluate the mechanical resistance of a weld. It would also permit to evaluate the process feasibility when complex geometrical components are to be made, and to optimize the welding sequences in order to minimize defects. This work deals with the numerical modelling of arc welding process of steels. After describing the industrial context and the state of art, the models implemented in TransWeld (software developed at CEMEF) are presented. The set of macroscopic equations is followed by a discussion on their numerical implementation. Then, the theory of re-meshing and our adaptive anisotropic re-meshing strategy are explained. Two welding metal addition techniques are investigated and are compared in terms of the joint size and transient temperature and stresses. The accuracy of the finite element model is evaluated based on experimental results and the results of the analytical solution. Comparative analysis between experimental and numerical results allows the assessment of the ability of the numerical code to predict the thermomechanical and metallurgical response of the welded structure. The models limitations and the phenomena identified during this study are finally discussed and permit to define interesting orientations for future developments. (author)

  5. Investigation on the stepping arc stud welding process

    Institute of Scientific and Technical Information of China (English)

    Chi Qiang; Zhang Jianxun; Fu Jifei; Zhang Youquan

    2005-01-01

    Through the investigation on traditional arc stud welding process, a new welding gun and its control system were developed in this paper. The stepping arc stud welding gun was mainly made by a stepping motor as actuating unit and a screw-driven device as moving unit. A control system with a MCS-51 single-chip microcomputer as main control component was used to realize the new stud welding procedure. This new welding process with stepping stud welding gun is named as stepping arc stud welding. In the new welding process, the stud action can be looked as constituted by some micro steps. The setting and adjusting of the stepping arc welding gun behavior parameters are accomplished independently. It is indicated from the results of process tests and bending test that the stepping arc stud welding process is practicable.

  6. 49 CFR 195.226 - Welding: Arc burns.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Welding: Arc burns. 195.226 Section 195.226 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Construction § 195.226 Welding: Arc burns. (a) Each arc burn must be repaired. (b) An arc burn...

  7. Effect of arc on radiation thermometry in welding process

    Institute of Scientific and Technical Information of China (English)

    李亮玉; 王燕; 武宝林

    2002-01-01

    The effect of arc on radiation thermometry is analyzed in a field close to the arc during the welding process, and the ratio of signal to noise and other factors are obtained for a small current arc .The method of the temperature measurement is feasible when the arc current is decreased to a smaller value in the welding process.

  8. Plasma Arc Augmented CO2 laser welding

    DEFF Research Database (Denmark)

    Bagger, Claus; Andersen, Mikkel; Frederiksen, Niels;

    2001-01-01

    In order to reduce the hardness of laser beam welded 2.13 mm medium strength steel CMn 250, a plasma arc has been used simultaneously with a 2.6 kW CO2 laser source. In a number of systematic laboratory tests, the plasma arc current, plasma gas flow and distance to the laser source were varied with....... With the addition of a plasma arc, the hardness could overall be reduced to between 200 and 220 HV1, i.e. about 27 percent. In the seam middle, the reduction was 36 percent....

  9. Simultaneous observation of keyhole and weld pool in plasma arc welding with a single cost-effective sensor

    Institute of Scientific and Technical Information of China (English)

    张国凯; 武传松; 刘新锋; 张晨

    2014-01-01

    The dynamic behaviors ofthe keyhole and weld pool are coupled together in plasma arc welding,and the geometric variations ofboth the keyhole and the weld pool determine the weld quality.It is ofgreat significance to simultaneously sense and monitor the keyhole and the weld pool behaviors by using a single low-cost vision sensor in plasma arc welding process.In this study,the keyhole and weld pool were observed and measured under different levels ofwelding current by using the near infrared sensing technology and the charge coupled device (CCD)sensing system.The shapes and relative position ofweld pool and keyhole under different conditions were compared and analyzed.The observation results lay solid foundation for controlling weld quality and understanding the underlying process mechanisms.

  10. Effect of arc distance on temperature field and weld shape during double-sided arc welding

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guangjun; ZHANG Huajun; GAO Hongming; WU Lin

    2009-01-01

    A new high efficiency welding method, double-sided double arc welding with double powers (DSAW-D), is developed for thick plate of low alloy high strength steel in this study. It is well known that the thermal cycles have an important influence on the microstructure, shape, stress, distortion and mechanical property. The DSA W-D method can control the tempernture field on a wide range by regulating the distance between two arcs, improve the rnicrostructure and prevent hot and cold cracking of high strength steel. But at present, the effect of arc distance on the temperature field and shape is not clear. Therefore, the paper researches the effect of arc distance on the temperature field and weld pool during DSA W-D using finite element method. The transient temperature field of different arc distance in DSAW-D is calculated.To verify the numerical results, the temperature is measured by the thermo-couple and the calculated results agree approximately with experimental data. Farther, the thermal property and mutual effect of double-sided arcs are investigated. The temperature distributions and weld pool profile at different arc distances are obtained. The results show that arc distance is a very important factor to affect the heat process.

  11. Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

    OpenAIRE

    Koray Yurtisik; Suha Tirkes; Igor Dykhno; C. Hakan Gur; Riza Gurbuz

    2013-01-01

    Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex mi...

  12. Laser strobe weld pool vision for robotic arc welding

    International Nuclear Information System (INIS)

    This paper describes continuing work in arc light suppression in the viewing of weld pool via a stroboscopic video system. In addition to refining the basic technique, the system has been extended in ways that will enhance its applicability to robotics and the adaptive control of welding processes, as well as provide a general diagnostic tool for welding production and research. In summary, the stroboscopic video technique uses a night vision image intensifier tube to gate video image with the illumination of the weld pool area supplied by a very strong repetitively pulsed light source such as a xenon flash lamp or a laser. Although the average optical power of illuminator is much lower than that of the arc, the peak power is much greater and the gated image almost completely suppresses the light of the arc. The image is then focused into a CCD camera whose video output is conventional and can be viewed in real time, analyzed line-by-line, or recorded on a standard video cassette recorder. The present work has branched in several directions. Two laser illumination sources have been developed. One is a pulsed ultraviolet laser with substantially more peak power than the xenon lamp, used for illuminating the rather difficult video environment found in the high-current GMA welding of aluminum plate. This laser has been mated with an optical fiber which delivers its light to the welding torch, a technique amenable to robotic applications. The other laser illumination source is based on infrared laser diodes; while much less powerful than other pulsed lasers, they are cheap, compact, rugged, and require little auxiliary equipment to operate

  13. Method for defect free keyhole plasma arc welding

    Science.gov (United States)

    Harwig, Dennis D. (Inventor); Hunt, James F. (Inventor); Ryan, Patrick M. (Inventor); Fisher, Walter J. (Inventor)

    1993-01-01

    A plasma arc welding process for welding metal of increased thickness with one pass includes operating the plasma arc welding apparatus at a selected plasma gas flow rate, travel speed and arc current, to form a weld having a penetration ratio to weld height to weld width, and maintaining the penetration ratio at less than 0.74. Parameters for the plasma gas flow rate, travel speed and arc current are adjusted to a steady state condition during a start up period and maintained during the steady state condition to complete a weld. During a terminal stopping period, the travel speed is stopped and instantaneously replaced by filler wire which adds material to fill the keyhole that had been formed by the welding process. Parameters are subsequently adjusted during the stopping period to terminate the weld in a sound manner.

  14. Variable-Polarity Plasma Arc Welding Of Alloy 2219

    Science.gov (United States)

    Walsh, Daniel W.; Nunes, Arthur C., Jr.

    1989-01-01

    Report presents results of study of variable-polarity plasma arc (VPPA) welding of aluminum alloy 2219. Consists of two parts: Examination of effects of microsegregation and transient weld stress on macrosegregation in weld pool and, electrical characterization of straight- and reverse-polarity portions of arc cycle.

  15. Study on DC welding parameters of Al-alloy shaping based on arc-welding robot

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    The Al-alloy arc-welding shaping system based on arc-welding robot is established, and the Al-alloy shaping manufacture is realized with the DC (direct current) gas metal arc welding (GMAW). The research indicates that the metal transfer type of DC GMAW, heat input and the initial temperature of the workpiece greatly affect the Al-alloy shaping based on arc welding robot. On the penetration, the weld width and the reinforcement, the influence of welding parameters is analyzed by generalized regression neural network (GRNN) fitting.

  16. 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.

  17. 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.

  18. Geometric model of robotic arc welding for automatic programming

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Geometric information is important for automatic programming of arc welding robot. Complete geometric models of robotic arc welding are established in this paper. In the geometric model of weld seam, an equation with seam length as its parameter is introduced to represent any weld seam. The method to determine discrete programming points on a weld seam is presented. In the geometric model of weld workpiece, three class primitives and CSG tree are used to describe weld workpiece. Detailed data structure is presented. In pose transformation of torch, world frame, torch frame and active frame are defined, and transformation between frames is presented. Based on these geometric models, an automatic programming software package for robotic arc welding, RAWCAD, is developed. Experiments show that the geometric models are practical and reliable.

  19. Effect of Gravity on Arc Shape in GTA Welding-for Low Electric Arc Current

    Institute of Scientific and Technical Information of China (English)

    Hidetoshi FUJII; Yosuke SUMI; Manabu TANAKA; Kiyoshi NOGI

    2003-01-01

    Gas tungsten arc (GTA) welding was performed both in a microgravity environment and in a terrestrial environment,and the arc shapes in both environments were compared. A microgravity condition was obtained using the free fallsystem at the Japan Microgravi

  20. Gas Contamination In Plasma-Arc-Welded Aluminum

    Science.gov (United States)

    Mcclure, John C.; Torres, Martin R.; Gurevitch, Alan C.; Newman, Robert A.

    1992-01-01

    Document describes experimental investigation on visible and tactile effects of gaseous contaminants in variable-polarity plasma arc (VPPA) welding of 2219 T-87 aluminum alloy. Contaminant gases (nitrogen, methane, oxygen, and hydrogen) introduced in argon arc and in helium shield gas in various controlled concentrations. Report represents results of experiments in form of photographs of fronts, backs, polished cross sections, and etched cross sections of welds made with various contaminants at various concentrations. Provides detailed discussion of conditions under which welds made.

  1. Evaluation of tandem gas metal arc welding for low distortion butt-welds in naval shipbuilding

    International Nuclear Information System (INIS)

    Tandem gas metal arc welding (T-GMAW) had been indentified as a welding process that is potentially capable of increasing productivity and minimizing distortion in the butt-welding of steel panels for the shipbuilding industry. In this study, the T-GMAW process has been used to butt-weld DH36 steel plate in order to determine its suitability as a replacement for submerged arc welding (SAW) or standard gas-metal-arc welding (GMAW) in naval shipbuilding applications. Experiments conducted show that the T-GMAW process is feasible and provides a significant improvement ove the SAW process in several respects, including higher travel speed, reduction in filler material, significantly lower post-weld distortion and residual stress, and a smaller heat affected zone (HAZ) with finer weld metal and HAZ microstructures. Furthermore, similar mechanical properties to those of SAW were obtained in the weld metal and HAZ.

  2. NTWV-based sensing keyhole dimension in plasma arc welding

    Institute of Scientific and Technical Information of China (English)

    Jia Chuanbao; Wu Chuansong; Zhang Yuming

    2008-01-01

    During stable keyhole plasma arc welding, the pilot arc and the transferred arc exist at the meantime, and the arcs can be considered as a composition of two parts inside and outside the nozzle, respectively. Under the mechanical constriction and thermal contraction effects, the inside arc has certain arc length, electron density and arc profile etc. Inducing constant tungsten-to-nozzle voltage. However, the arc outside the nozzle diverges at about 5 degrees and has certain characteristics similar to the free arcs. The nozzle-to-workpiece voltage (NTWV) depends mainly on the length of the arc, which gets bigger as increasing of the weld penetration and keyhole size. The NTWV sensor is developed for monitoring NTWV in real time. The welding experiments are designed to get different penetrations and keyhole sizes. It is found that as the weld penetration and the keyhole size increase, NTWV also increases linearly. The NTWV signals can be used as the feedback variable in automatic control of keyhole plasma arc welding.

  3. 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

  4. 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.

  5. Simulation of temperature fields in arc and beam welding

    Science.gov (United States)

    Mahrle, A.; Schmidt, J.; Weiss, D.

    Heat and mass transfer in arc and beam welding is considered. The main objectives are analysis of the heat transfer in the weld pool and the workpiece and to demonstrate how computer simulation can be used as a tool to predict the temperature distribution as the determining element of the heat effects of welding. Simulation results of two particular welding processes are compared and validated with measurements.

  6. Process characteristics of fibre-laser-assisted plasma arc welding

    Energy Technology Data Exchange (ETDEWEB)

    Mahrle, A; Schnick, M; Rose, S; Demuth, C; Beyer, E; Fuessel, U, E-mail: achim.mahrle@iws.fraunhofer.de [Dresden University of Technology, Institute of Surface and Manufacturing Technology, PO Box, D-01062 Dresden (Germany)

    2011-08-31

    Experimental and theoretical investigations on fibre-laser-assisted plasma arc welding (LAPW) were performed. Welding experiments were carried out on aluminium and steel sheets. In the case of a highly focused laser beam and a separate arrangement of plasma torch and laser beam, high-speed video recordings of the plasma arc and corresponding measurements of the time-dependent arc voltage revealed differences in the process behaviour for both materials. In the case of aluminium welding, a sharp decline in arc voltage and stabilization and guiding of the anodic arc root was observed whereas in steel welding the arc voltage was slightly increased after the laser beam was switched on. However, significant improvement of the melting efficiency with the combined action of plasma arc and laser beam was achieved for both types of material. Theoretical results of additional numerical simulations of the arc behaviour suggest that the properties of the arc plasma are mainly influenced not by a direct interaction with the laser radiation but by the laser-induced evaporation of metal. Arc stabilization with increased current densities is predicted for moderate rates of evaporated metal only whereas metal vapour rates above a certain threshold causes a destabilization of the arc and reduced current densities along the arc axis.

  7. Process characteristics of fibre-laser-assisted plasma arc welding

    Science.gov (United States)

    Mahrle, A.; Schnick, M.; Rose, S.; Demuth, C.; Beyer, E.; Füssel, U.

    2011-08-01

    Experimental and theoretical investigations on fibre-laser-assisted plasma arc welding (LAPW) were performed. Welding experiments were carried out on aluminium and steel sheets. In the case of a highly focused laser beam and a separate arrangement of plasma torch and laser beam, high-speed video recordings of the plasma arc and corresponding measurements of the time-dependent arc voltage revealed differences in the process behaviour for both materials. In the case of aluminium welding, a sharp decline in arc voltage and stabilization and guiding of the anodic arc root was observed whereas in steel welding the arc voltage was slightly increased after the laser beam was switched on. However, significant improvement of the melting efficiency with the combined action of plasma arc and laser beam was achieved for both types of material. Theoretical results of additional numerical simulations of the arc behaviour suggest that the properties of the arc plasma are mainly influenced not by a direct interaction with the laser radiation but by the laser-induced evaporation of metal. Arc stabilization with increased current densities is predicted for moderate rates of evaporated metal only whereas metal vapour rates above a certain threshold causes a destabilization of the arc and reduced current densities along the arc axis.

  8. Process characteristics of fibre-laser-assisted plasma arc welding

    International Nuclear Information System (INIS)

    Experimental and theoretical investigations on fibre-laser-assisted plasma arc welding (LAPW) were performed. Welding experiments were carried out on aluminium and steel sheets. In the case of a highly focused laser beam and a separate arrangement of plasma torch and laser beam, high-speed video recordings of the plasma arc and corresponding measurements of the time-dependent arc voltage revealed differences in the process behaviour for both materials. In the case of aluminium welding, a sharp decline in arc voltage and stabilization and guiding of the anodic arc root was observed whereas in steel welding the arc voltage was slightly increased after the laser beam was switched on. However, significant improvement of the melting efficiency with the combined action of plasma arc and laser beam was achieved for both types of material. Theoretical results of additional numerical simulations of the arc behaviour suggest that the properties of the arc plasma are mainly influenced not by a direct interaction with the laser radiation but by the laser-induced evaporation of metal. Arc stabilization with increased current densities is predicted for moderate rates of evaporated metal only whereas metal vapour rates above a certain threshold causes a destabilization of the arc and reduced current densities along the arc axis.

  9. Relationship between arc voltage current and arc length in TIG welding

    International Nuclear Information System (INIS)

    The relationship between arc voltage, arc length and current in Tungsten Inert Gas welding has been investigated. It was not possible to determine a correlation between arc voltage, current and arc length because of the inherent variability in the experimental results. A typical value for the error in controlling the arc length using arc voltage was calculated and found to be ± 0.5mm. The variation in arc voltage at constant conditions has two components, long term and short term. Long term is the variation in voltage between welds, short term is voltage variation within a few seconds. Both are about 5% of the total arc voltage. Since only a fraction of the arc voltage depends on arc length, this leads to a much larger variation in arc length if Arc Voltage Control (AVC) is used to control arc length (about 15% in each case at 3mm arc length). A weld procedure based on AVC is likely to yield a different variability in weld bead geometry from one based on constant arc length. (author)

  10. Effect of Pulse Parameters on Weld Quality in Pulsed Gas Metal Arc Welding: A Review

    Science.gov (United States)

    Pal, Kamal; Pal, Surjya K.

    2011-08-01

    The weld quality comprises bead geometry and its microstructure, which influence the mechanical properties of the weld. The coarse-grained weld microstructure, higher heat-affected zone, and lower penetration together with higher reinforcement reduce the weld service life in continuous mode gas metal arc welding (GMAW). Pulsed GMAW (P-GMAW) is an alternative method providing a better way for overcoming these afore mentioned problems. It uses a higher peak current to allow one molten droplet per pulse, and a lower background current to maintain the arc stability. Current pulsing refines the grains in weld fusion zone with increasing depth of penetration due to arc oscillations. Optimum weld joint characteristics can be achieved by controlling the pulse parameters. The process is versatile and easily automated. This brief review illustrates the effect of pulse parameters on weld quality.

  11. A unified model of transport phenomena in gas metal arc welding including electrode, arc plasma and molten pool

    International Nuclear Information System (INIS)

    This paper presents a theoretical model for describing globular transfer in gas metal arc welding. The heat and mass transfer in the electrode, arc plasma and molten pool are considered in one unified model. Using the volume of fluid method, the transport phenomena are dynamically studied in the following processes: droplet formation and detachment, droplet flight in arc plasma, impingement of droplets on the molten pool and solidification after the arc extinguishes. The simulation of heat and mass transfer in the arc plasma considers the developing surface profile of the electrode and molten pool and also the effect of the flying droplet inside the arc plasma. Furthermore, the heat inputs to the electrode and the molten pool result from the simulation of the arc plasma. In addition, a He-Ne laser in conjunction with the shadow-graphing technique is used to observe the metal-transfer process. The theoretical predictions and experimental results are shown to be in good agreement

  12. Effects of relative positioning of energy sources on weld integrity for hybrid laser arc welding

    Science.gov (United States)

    Liu, Shuangyu; Li, Yanqing; Liu, Fengde; Zhang, Hong; Ding, Hongtao

    2016-06-01

    This study is concerned with the effects of laser and arc arrangement on weld integrity for the hybrid laser arc welding processes. Experiments were conducted for a high-strength steel using a 4 kW Nd: YAG laser and a metal active gas (MAG) welding facility under two configurations of arc-laser hybrid welding (ALHW) and laser-arc hybrid welding (LAHW). Metallographic analysis and mechanical testing were performed to evaluate the weld integrity in terms of weld bead geometry, microstructure and mechanical properties. The morphology of the weld bead cross-section was studied and the typical macrostructure of the weld beads appeared to be cone-shaped and cocktail cup-shaped under ALHW and LAHW configurations, respectively. The weld integrity attributes of microstructure, phase constituents and microhardness were analyzed for different weld regions. The tensile and impact tests were performed and fracture surface morphology was analyzed by scanning electron microscope. The study showed that ALHW produced joints with a better weld shape and a more uniform microstructure of lath martensite, while LAHW weld had a heterogeneous structure of lath martensite and austenite.

  13. Recent progress on gas tungsten arc welding of vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Grossbeck, M.L.; King, J.F.; Alexander, D.J. [Oak Ridge National Lab., TN (United States)] [and others

    1997-08-01

    Emphasis has been placed on welding 6.4 mm plate, primarily by gas tungsten arc (GTA) welding. The weld properties were tested using blunt notch Charpy testing to determine the ductile to brittle transition temperature (DBTT). Erratic results were attributed to hydrogen and oxygen contamination of the welds. An improved gas clean-up system was installed on the welding glove box and the resulting high purity welds had Charpy impact properties similar to those of electron beam welds with similar grain size. A post-weld heat treatment (PWHT) of 950{degrees}C for two hours did not improve the properties of the weld in cases where low concentrations of impurities were attained. Further improvements in the gas clean-up system are needed to control hydrogen contamination.

  14. Characterization of duplex stainless steel weld metals obtained by hybrid plasma-gas metal arc welding

    Directory of Open Access Journals (Sweden)

    Koray Yurtisik

    2013-09-01

    Full Text Available Despite its high efficiency, autogenous keyhole welding is not well-accepted for duplex stainless steels because it causes excessive ferrite in as-welded duplex microstructure, which leads to a degradation in toughness and corrosion properties of the material. Combining the deep penetration characteristics of plasma arc welding in keyhole mode and metal deposition capability of gas metal arc welding, hybrid plasma - gas metal arc welding process has considered for providing a proper duplex microstructure without compromising the welding efficiency. 11.1 mm-thick standard duplex stainless steel plates were joined in a single-pass using this novel technique. Same plates were also subjected to conventional gas metal arc and plasma arc welding processes, providing benchmarks for the investigation of the weldability of the material. In the first place, the hybrid welding process enabled us to achieve less heat input compared to gas metal arc welding. Consequently, the precipitation of secondary phases, which are known to be detrimental to the toughness and corrosion resistance of duplex stainless steels, was significantly suppressed in both fusion and heat affected zones. Secondly, contrary to other keyhole techniques, proper cooling time and weld metal chemistry were achieved during the process, facilitating sufficient reconstructive transformation of austenite in the ferrite phase.

  15. Role of arc mode in laser-metal active gas arc hybrid welding of mild steel

    International Nuclear Information System (INIS)

    Highlights: • Pulsed arc is more effective to improve the stability of laser-arc hybrid welding. • LCHW has the highest fraction of acicular ferrite and high-angle grain boundaries. • Grain refinement depends on effective current of the arc. • LSHW has the most apparent vestige of texture components. • The microstructure and microtexture formation mechanisms were summarized. - Abstract: Arc mode plays an important role in joint characterizations of arc welding, but it has been seldom considered in laser-arc hybrid welding. This paper investigated the role of arc mode on laser-metal active gas (MAG) arc hybrid welding of mild steel. Three arc modes were employed, which were cold metal transfer (CMT), pulsed spray arc and standard short circuiting arc. Microtexture of the joints were observed and measured via electron back scattering diffraction (EBSD) system to reveal the effect of arc mode on microstructure. Mechanical properties of the joints were evaluated by tensile and Charpy V-notch impact tests. It was found that both the stability and mechanical properties of laser-CMT hybrid welding (LCHW) is the best, while those of laser-standard short circuiting arc welding (LSHW) is the worst. OM and EBSD results showed that the fraction of acicular ferrite and high-angle grain boundaries in fusion zone decreases gradually in the sequence of LCHW, laser-pulsed spray arc welding and LSHW, while the mean grain size increases gradually. Finally, the microstructure formation mechanisms and the relationship between microstructure and mechanical properties were summarized by the loss of alloying element and the stirring effect in molten pool

  16. 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...

  17. Influence of the arc plasma parameters on the weld pool profile in TIG welding

    International Nuclear Information System (INIS)

    Magneto-hydrodynamic simulations of the arc and fluid simulations of the weld pool can be beneficial in the analysis and further development of arc welding processes and welding machines. However, the appropriate coupling of arc and weld pool simulations needs further improvement. The tungsten inert gas (TIG) welding process is investigated by simulations including the weld pool. Experiments with optical diagnostics are used for the validation. A coupled computational model of the arc and the weld pool is developed using the software ANSYS CFX. The weld pool model considers the forces acting on the motion of the melt inside and on the surface of the pool, such as Marangoni, drag, electromagnetic forces and buoyancy. The experimental work includes analysis of cross-sections of the workpieces, highspeed video images and spectroscopic measurements. Experiments and calculations have been performed for various currents, distances between electrode and workpiece and nozzle diameters. The studies show the significant impact of material properties like surface tension dependence on temperature as well as of the arc structure on the weld pool behaviour and finally the weld seam depth. The experimental weld pool profiles and plasma temperatures are in good agreement with computational results

  18. Approximate entropy--a new statistic to quantify arc and welding process stability in short-circuiting gas metal arc welding

    Institute of Scientific and Technical Information of China (English)

    Cao Biao; Xiang Yuan-Peng; Lü Xiao-Qing; Zeng Min; Huang Shi-Sheng

    2008-01-01

    Based on the phase state reconstruction of welding current in short-circuiting gas metal arc welding using carbon dioxide as shielding gas, the approximate entropy of welding current as well as its standard deviation has been calculated and analysed to investigate their relation with the stability of electric arc and welding process. The extensive experimental and calculated results show that the approximate entropy of welding current is significantly and positively correlated with arc and welding process stability, whereas its standard deviation is correlated with them negatively. A larger approximate entropy and a smaller standard deviation imply a more stable arc and welding process, and vice versa. As a result, the approximate entropy of welding current promises well in assessing and quantifying the stability of electric arc and welding process in short-circuiting gas metal arc welding.

  19. Adaptive Real-time Predictive Compensation Control for 6-DOF Serial Arc Welding Manipulator

    Institute of Scientific and Technical Information of China (English)

    WANG Xuanyin; DING Yuanming

    2010-01-01

    Because of long driving chain and great system load inertia, the serial manipulator has a serious time delay problem which leads to significant real-time tracking control errors and damages the welding quality finally. In order to solve the time delay problem and enhance the welding quality, an adaptive real-time predictive compensation control(ARTPCC) is presented in this paper. The ARTPCC technique combines offline identification and online compensation. Based on the neural network system identification technique, the ARTPCC technique identifies the dynamic joint model of the 6-DOF serial arc welding manipulator offline. With the identified dynamic joint model, the ARTPCC technique predicts and compensates the tracking error online using the adaptive friction compensation technique. The ARTPCC technique is proposed in detail in this paper and applied in the real-time tracking control experiment of the 6-DOF serial arc welding manipulator. The tracking control experiment results of the end-effector reference point of the manipulator show that the presented control technique reduces the tracking error, enhances the system response and tracking accuracy efficiently. Meanwhile, the welding experiment results show that the welding seam turns more continuous, uniform and smooth after using the ARTPCC technique. With the ARTPCC technique, the welding quality of the 6-DOF serial arc welding manipulator is highly improved.

  20. 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.

  1. Spectroscopic measurement of hydrogen contamination in weld arc plasmas

    Science.gov (United States)

    Shea, J. E.; Gardner, C. S.

    1983-09-01

    The introduction of hydrogen into metals during welding is known to cause hydrogen assisted cracking and embrittlement in certain situations. It has been shown that the weld metal hydrogen content is directly related to hydrogen concentration in the weld arc plasma. In this paper we describe a simple spectroscopic technique for measuring the arc plasma hydrogen concentration in real time when an argon shield gas is used. This technique is based on the fact that the intensity ratio of the hydrogen Balmer Alpha emission line at 6563 Å and an argon emission line at 6965 Å was observed to be an approximately linear function of hydrogen concentration in the weld arc plasma. This technique was experimentally verified under a variety of welding conditions for gas metal arc welding and found to have an error of less than 10% when measuring hydrogen concentrations in the arc plasma as low as 0.25% by volume. This method of hydrogen measurement is also applicable when welding with shield gases not containing argon so long as a suitable ratioing line is available.

  2. Spectroscopic measurement of hydrogen contamination in weld arc plasmas

    International Nuclear Information System (INIS)

    The introduction of hydrogen into metals during welding is known to cause hydrogen assisted cracking and embrittlement in certain situations. It has been shown that the weld metal hydrogen content is directly related to hydrogen concentration in the weld arc plasma. In this paper we describe a simple spectroscopic technique for measuring the arc plasma hydrogen concentration in real time when an argon shield gas is used. This technique is based on the fact that the intensity ratio of the hydrogen Balmer Alpha emission line at 6563 A and an argon emission line at 6965 A was observed to be an approximately linear function of hydrogen concentration in the weld arc plasma. This technique was experimentally verified under a variety of welding conditions for gas metal arc welding and found to have an error of less than 10% when measuring hydrogen concentrations in the arc plasma as low as 0.25% by volume. This method of hydrogen measurement is also applicable when welding with shield gases not containing argon so long as a suitable ratioing line is available

  3. In-situ weld-alloying plasma arc welding of SiCp/Al MMC

    Institute of Scientific and Technical Information of China (English)

    LEI Yu-cheng; YUAN Wei-jin; CHEN Xi-zhang; ZHU Fei; CHENG Xiao-nong

    2007-01-01

    Plasma arc welding was used to join SiCp/Al composite with titanium as alloying filler material. Microstructure of the weld was characterized by an optical microscope. The results show that the harmful needle-like phase Al4C3 is completely eliminated in the weld of SiCp/Al metal matrix composite(MMC) by in-situ weld-alloying/plasma arc welding with titanium as the alloying element. The wetting property between reinforced phase and Al matrix is improved, a stable weld puddle is gotten and a novel composite-material welded joint reinforced by TiN, AlN and TiC is produced. And the tensile-strength and malleability of the welded joints are improved effectively because of the use of titanium.

  4. 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.

  5. Immunotoxicology of arc welding fume: Worker and experimental animal studies

    OpenAIRE

    Zeidler-Erdely, Patti C; Erdely, Aaron; Antonini, James M.

    2012-01-01

    Arc welding processes generate complex aerosols composed of potentially hazardous metal fumes and gases. Millions of workers worldwide are exposed to welding aerosols daily. A health effect of welding that is of concern to the occupational health community is the development of immune system dysfunction. Increased severity, frequency, and duration of upper and lower respiratory tract infections have been reported among welders. Specifically, multiple studies have observed an excess mortality ...

  6. Modelling of GMA welding in short-arc mode; Modelisation du soudage MIG/MAG en mode short-arc

    Energy Technology Data Exchange (ETDEWEB)

    Planckaert, J.P

    2008-07-15

    Nowadays there is a lot of welding processes giving an answer to the great diversity of joints to realize and to the characteristics of the metals employed. The first chapter describes the different power sources used in welding. After that, a more detailed explanation of arc welding is given. Finally we present the design of a welding test bed. One can, of course, use an empirical approach to optimize a process. Nevertheless there are advantages in choosing an analytical approach since we can expect significant progress in the understanding of the dynamical interactions in the arc. That's why we present in the second chapter the theoretical knowledge concerning the behaviour of the molten metal transferred during Gas Metal Arc Welding. This work involves as well an experimental aspect required for the elaboration of the databases used to build the model. The recordings were made at CTAS on a test bed equipped with an acquisition system for measuring voltage, current, wire feed speed and high speed videos. The third chapter presents our research of a segmentation method to measure some relevant quantities. We propose a software sensor based on the active contour theory and we show good results on experimental movies. An adjustment step of the model is needed and described in the fourth chapter. The created simulator allows us to interpret some important phenomena in welding, to make a sensitive study 'without risk' and to give theoretical defect signatures. (author)

  7. Effect of acoustic field parameters on arc acoustic binding during ultrasonic wave-assisted arc welding.

    Science.gov (United States)

    Xie, Weifeng; Fan, Chenglei; Yang, Chunli; Lin, Sanbao

    2016-03-01

    As a newly developed arc welding method, power ultrasound has been successfully introduced into arc and weld pool during ultrasonic wave-assisted arc welding process. The advanced process for molten metals can be realized by utilizing additional ultrasonic field. Under the action of the acoustic wave, the plasma arc as weld heat source is regulated and its characteristics make an obvious change. Compared with the conventional arc, the ultrasonic wave-assisted arc plasma is bound significantly and becomes brighter. To reveal the dependence of the acoustic binding force on acoustic field parameters, a two-dimensional acoustic field model for ultrasonic wave-assisted arc welding device is established. The influences of the radiator height, the central pore radius, the radiator radius, and curvature radius or depth of concave radiator surface are discussed using the boundary element method. Then the authors analyze the resonant mode by this relationship curve between acoustic radiation power and radiator height. Furthermore, the best acoustic binding ability is obtained by optimizing the geometric parameters of acoustic radiator. In addition, three concave radiator surfaces including spherical cap surface, paraboloid of revolution, and rotating single curved surface are investigated systematically. Finally, both the calculation and experiment suggest that, to obtain the best acoustic binding ability, the ultrasonic wave-assisted arc welding setup should be operated under the first resonant mode using a radiator with a spherical cap surface, a small central pore, a large section radius and an appropriate curvature radius. PMID:26558995

  8. Study of Mechanical Properties and Characterization of Pipe Steel welded by Hybrid (Friction Stir Weld + Root Arc Weld) Approach

    Energy Technology Data Exchange (ETDEWEB)

    Lim, Yong Chae [ORNL; Sanderson, Samuel [MegaStir Technologies LLC; Mahoney, Murray [Consultant; Wasson, Andrew J [ExxonMobil, Upstream Research Company (URC); Fairchild, Doug P [ExxonMobil, Upstream Research Company (URC); Wang, Yanli [ORNL; Feng, Zhili [ORNL

    2015-01-01

    Friction stir welding (FSW) has recently attracted attention as an alternative construction process for gas/oil transportation applications due to advantages compared to fusion welding techniques. A significant advantage is the ability of FSW to weld the entire or nearly the entire wall thickness in a single pass, while fusion welding requires multiple passes. However, when FSW is applied to a pipe or tube geometry, an internal back support anvil is required to resist the plunging forces exerted during FSW. Unfortunately, it may not be convenient or economical to use internal backing support due to limited access for some applications. To overcome this issue, ExxonMobil recently developed a new concept, combining root arc welding and FSW. That is, a root arc weld is made prior to FSW that supports the normal loads associated with FSW. In the present work, mechanical properties of a FSW + root arc welded pipe steel are reported including microstructure and microhardness.

  9. 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.

  10. 30 CFR 75.1106 - Welding, cutting, or soldering with arc or flame underground.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding, cutting, or soldering with arc or... Protection § 75.1106 Welding, cutting, or soldering with arc or flame underground. All welding, cutting, or... conducted in fireproof enclosures. Welding, cutting, or soldering with arc or flame in other than...

  11. 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...

  12. The origins of acicular ferrite in gas metal arc and submerged arc welds

    OpenAIRE

    Brothers, Daniel G.

    1994-01-01

    The nature of weld metal inclusions in relation to the formation of acicular ferrite was investigated. Gas-metal arc welds (GMAW) on High Strength Low Alloy (HSLA) plate with varying amounts of oxygen and/or carbon dioxide added to the argon cover gas and submerged arc welds (SAW) on HY-100 plate with five different fluxes were analyzed. This analysis determined the effect of weld metal composition on non-metallic inclusion composition and the ultimate effects on the formation of acicular fer...

  13. Stud arc welding in a magnetic field - Investigation of the influences on the arc motion

    Science.gov (United States)

    Hartz-Behrend, K.; Marqués, J. L.; Forster, G.; Jenicek, A.; Müller, M.; Cramer, H.; Jilg, A.; Soyer, H.; Schein, J.

    2014-11-01

    Stud arc welding is widely used in the construction industry. For welding of studs with a diameter larger than 14 mm a ceramic ferrule is usually necessary in order to protect the weld pool. Disadvantages of using such a ferrule are that more metal is molten than necessary for a high quality welded joint and that the ferrule is a consumable generally thrown away after the welding operation. Investigations show that the ferrule can be omitted when the welding is carried out in a radially symmetric magnetic field within a shielding gas atmosphere. Due to the Lorentz force the arc is laterally shifted so that a very uniform and controlled melting of the stud contact surface as well as of the work piece can be achieved. In this paper a simplified physical model is presented describing how the parameters welding current, flux density of the magnetic field, radius of the arc and mass density of the shielding gas influence the velocity of the arc motion. The resulting equation is subsequently verified by comparing it to optical measurements of the arc motion. The proposed model can be used to optimize the required field distribution for the magnetic field stud welding process.

  14. Stud arc welding in a magnetic field – Investigation of the influences on the arc motion

    International Nuclear Information System (INIS)

    Stud arc welding is widely used in the construction industry. For welding of studs with a diameter larger than 14 mm a ceramic ferrule is usually necessary in order to protect the weld pool. Disadvantages of using such a ferrule are that more metal is molten than necessary for a high quality welded joint and that the ferrule is a consumable generally thrown away after the welding operation. Investigations show that the ferrule can be omitted when the welding is carried out in a radially symmetric magnetic field within a shielding gas atmosphere. Due to the Lorentz force the arc is laterally shifted so that a very uniform and controlled melting of the stud contact surface as well as of the work piece can be achieved. In this paper a simplified physical model is presented describing how the parameters welding current, flux density of the magnetic field, radius of the arc and mass density of the shielding gas influence the velocity of the arc motion. The resulting equation is subsequently verified by comparing it to optical measurements of the arc motion. The proposed model can be used to optimize the required field distribution for the magnetic field stud welding process

  15. The variable polarity plasma arc welding process: Characteristics and performance

    Science.gov (United States)

    Hung, R. J.; Zhu, G. J.

    1991-01-01

    Significant advantages of the Variable Polarity Plasma Arc (VPPA) Welding Process include faster welding, fewer repairs, less joint preparation, reduced weldment distortion, and absence of porosity. The power distribution was analyzed for an argon plasma gas flow constituting the fluid in the VPPA Welding Process. The major heat loss at the torch nozzle is convective heat transfer; in the space between the outlet of the nozzle and the workpiece; radiative heat transfer; and in the keyhole in the workpiece, convective heat transfer. The power absorbed at the workpiece produces the molten puddle that solidifies into the weld bead. Crown and root widths, and crown and root heights of the weld bead are predicted. The basis is provided for an algorithm for automatic control of VPPA welding machine parameters to obtain desired weld bead dimensions.

  16. Simulation of Weld Depth in A-TIG Welding with Unified Arc-electrode model

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Calculations have been made for weld depths occurring for TIG welding activated by a flux over the surface of the weld pool. In this case, the flux introduces an electrically insulating layer over the outer regions of the weld-pool surface. There is then an increase in the current density at the surface of the centre of the weld-pool with a consequent increase in the J×B forces, which drive a strong convective flow of the molten metal downwards, tending to make a deep weld. For a flux which produces an insulating layer for all but a central region of radius 2 mm, the calculated weld-depth is 7 mm, and an arc spot is predicted at the centre of the weld-pool surface. As yet we have not resolved the reason for significant differences that exist between our measurements of weld depth and the theoretical predictions.

  17. Self-clamping arc light reflector for welding torch

    Science.gov (United States)

    Gordon, Stephen S.

    1987-07-01

    This invention is directed to a coaxial extending metal mirror reflector attached to the electrode housing or gas cup on a welding torch. An electric welding torch with an internal viewing system for robotic welding is provded with an annular arc light reflector to reflect light from the arc back onto the workpiece. The reflector has a vertical split or gap in its surrounding wall to permit the adjacent wall ends forming the split to be sprung open slightly to permit the reflector to be removed or slipped onto the torch housing or gas cup. The upper opening of the reflector is slightly smaller than the torch housing or gas cup and therefore, when placed on the torch housing or gas cup has that springiness to cause it to clamp tightly on the housing or gas cup. The split or gap also serves to permit the feed of weld wire through to the weld area,

  18. In process acoustic emission in multirun submerged arc welding

    International Nuclear Information System (INIS)

    In order to avoid the formation of deep grooves when repairing defects in welded joints in heavy plates, an investigation was made aiming to detect and locate the defects by in-process acoustic emission in multirun submerged arc welding. Twelve defects (lack of penetration, cracks, inclusions, lack of fusion together with inclusions, blowholes) were intentionally introduced when the first plate was welded. A space-time method for processing the acoustic activity during welding allowed the detection and the location of the intentional defects as well as of the most important accidental defects evidenced by ultrasonic testing

  19. Optical emission spectroscopy of metal vapor dominated laser-arc hybrid welding plasma

    International Nuclear Information System (INIS)

    During laser-arc hybrid welding, plasma properties affect the welding process and the weld quality. However, hybrid welding plasmas have not been systematically studied. Here we examine electron temperatures, species densities, and electrical conductivity for laser, arc, and laser-arc hybrid welding using optical emission spectroscopy. The effects of arc currents and heat source separation distances were examined because these parameters significantly affect weld quality. Time-average plasma electron temperatures, electron and ion densities, electrical conductivity, and arc stability decrease with increasing heat source separation distance during hybrid welding. Heat source separation distance affects these properties more significantly than the arc current within the range of currents considered. Improved arc stability and higher electrical conductivity of the hybrid welding plasma result from increased heat flux, electron temperatures, electron density, and metal vapor concentrations relative to arc or laser welding.

  20. Modelling of transport phenomena in gas tungsten arc welding

    Directory of Open Access Journals (Sweden)

    A.H. Kokabi

    2007-07-01

    Full Text Available Purpose: Since numerical heat transfer and fluid flow models have provided significant insight into welding process and welded materials that could not been achieved otherwise, there has been an important interest in the quantitative representation of transport phenomena in the weld pool. On the other hand, the temperature and velocity distributions of the molten metal as well as the cooling rate after welding operation affect the weld geometry, the microstructure, and the mechanical properties of weld zone. This work demonstrates that the application of numerical transport phenomena can significantly add to the quantitative knowledge in welding and help the welding community in solving practical problems.Design/methodology/approach: The temperature and velocity fields are simulated using the solution of the equations of conversation of mass, energy and momentum in three-dimension and under steady-state heat transfer and fluid flow conditions.Findings: The weld pool geometry and various solidification parameters were calculated. The calculated weld pool geometries were in good agreement with the ones obtained using the experiments. The solidification parameters of G and G/R are determined. It is found that as the welding speed increases, the value of G/R at the weld pool centerline decreases.Research limitations/implications: Welding process used is this study is gas tungsten arc (GTA welding and base metal is commercial pure aluminum. This model can be investigated to simulate other materials and welding processes. Also the results of this study such as the temperature field can be used in the simulation of microstructure, mechanical properties, etc of welding zone.Originality/value: In this research the solidification parameters of G, R and G/R can be used for prediction of the solidification morphology and the scale of the solidification structure.

  1. Study on visual image information detection of external angle weld based on arc welding robot

    Science.gov (United States)

    Liu, Xiaorui; Liu, Nansheng; Sheng, Wei; Hu, Xian; Ai, Xiaopu; Wei, Yiqing

    2009-11-01

    Nowadays, the chief development trend in modern welding technology is welding automation and welding intelligence. External angle weld has a certain proportion in mechanical manufacture industries. In the real-time welding process, due to hot deformation and the fixture of workpieces used frequently, torch will detach welding orbit causes deviation, which will affect welding quality. Therefore, elimination weld deviation is the key to the weld automatic tracking system. In this paper, the authors use the self-developed structured light vision sensor system which has significant advantage compared with arc sensors to capture real-time weld images. In the project of VC++6.0 real-time weld image processing, after binaryzation with threshold value seventy, 3*1 median filter, thinning, obtain weld main stripe. Then, using the extraction algorithm this paper proposed to obtain weld feature points, and compute position of weld. Experiment result verified that the extraction algorithm can locate feature points rapidly and compute the weld deviation accurately.

  2. Underwater cladding with laser beam and plasma arc welding

    International Nuclear Information System (INIS)

    Two welding processes, plasma arc (transferred arc) (PTA) and laser beam, were investigated to apply cladding to austenitic stainless steels and Inconel 600. These processes have long been used to apply cladding layers , but the novel feature being reported here is that these cladding layers were applied underwater, with a water pressure equivalent to 24 m (80 ft). Being able to apply the cladding underwater is very important for many applications, including the construction of off-shore oil platforms and the repair of nuclear reactors. In the latter case, being able to weld underwater eliminates the need for draining the reactor and removing the fuel. Welding underwater in reactors presents numerous challenges, but the ability to weld without having to drain the reactor and remove the fuel provides a huge cost savings. Welding underwater in reactors must be done remotely, but because of the radioactive corrosion products and neutron activation of the steels, remote welding would also be required even if the reactor is drained and the fuel removed. In fact, without the shielding of the water, the remote welding required if the reactor is drained might be even more difficult than that required with underwater welds. Furthermore, as shall be shown, the underwater welds that the authors have made were of high quality and exhibit compressive rather than tensile residual stresses

  3. Method to reduce arc blow during DC arc welding of pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Espina-Hernandez, J. H.; Rueda-Morales, G.L.; Caleyo, F.; Hallen, J. M. [Instituto Politecnico Nacional, Mexico, (Mexico); Lopez-Montenegro, A.; Perz-Baruch, E. [Pemex Exploracion y Produccion, Tabasco, (Mexico)

    2010-07-01

    Steel pipelines are huge ferromagnetic structures and can be easily subjected to arc blow during the DC arc welding process. The development of methods to avoid arc blow during pipeline DC arc welding is a major objective in the pipeline industry. This study developed a simple procedure to compensate the residual magnetic field in the groove during DC arc welding. A Gaussmeter was used to perform magnetic flux density measurements in pipelines in southern Mexico. These data were used to perform magnetic finite element simulations using FEMM. Different variables were studied such as the residual magnetic field in the groove or the position of the coil with respect to the groove. An empirical predictive equation was developed from these trials to compensate for the residual magnetic field. A new method of compensating for the residual magnetic field in the groove by selecting the number of coil turns and the position of the coil with respect to the groove was established.

  4. 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

  5. Boosting Active Contours for Weld Pool Visual Tracking in Automatic Arc Welding

    DEFF Research Database (Denmark)

    Liu, Jinchao; Fan, Zhun; Olsen, Søren Ingvor;

    2015-01-01

    Detecting the shape of the non-rigid molten metal during welding, so-called weld pool visual sensing, is one of the central tasks for automating arc welding processes. It is challenging due to the strong interference of the high-intensity arc light and spatters as well as the lack of robust...... approaches to detect and represent the shape of the nonrigid weld pool. We propose a solution using active contours including an prior for the weld pool boundary composition. Also, we apply Adaboost to select a small set of features that captures the relevant information. The proposed method is applied to...... weld pool tracking and the presented results verified its feasibility....

  6. The temporal nature of forces acting on metal drops in gas metal arc welding

    Energy Technology Data Exchange (ETDEWEB)

    Jones, L.A.; Eagar, T.W.; Lang, J.H. [Massachusetts Institute of Technology, Cambridge, MA (United States)

    1996-12-31

    At moderate and high welding currents, the most important forces in gas metal arc welding acting on the molten electrode are magnetic forces arising from the interaction between the welding current and its own magnetic field. These forces drive the dynamic evolution of the drop and also depend on the instantaneous shape of the drop. In this paper, experimentally observed manifestations of magnetic forces are shown, and a technique for approximating the temporal evolution of these forces from experimentally measured drop shapes is reported. The technique provides quantitative data illustrating the large increase in the magnetic forces as a drop detaches from the electrode.

  7. The Impact of Teaching Oxy-Fuel Welding on Gas Metal Arc Welding Skills

    Science.gov (United States)

    Sgro, Sergio D.; Field, Dennis W.; Freeman, Steven A.

    2008-01-01

    Industrial technology programs around the country must be sensitive to the demands of manufacturing and industry as they continue to replace "vocational" curriculum with high-tech alternatives. This article examines whether or not teaching oxyacetylene welding in the industrial technology classroom is required to learn arc welding processes. The…

  8. Characterization of titanium welded joints by the orbital gas tungsten arc welding process for aerospace application

    OpenAIRE

    José A. Orlowski de Garcia; Gérson Luiz de Lima; Wilson D. Bocallão Pereira; Valdir Alves Guimarães; Carlos de Moura Neto; Ronaldo Pinheiro R. Paranhos

    2010-01-01

    In this work, three welding programs for orbital gas tungsten arc welding (GTAW), previously developed, were used, using pulsed current and increasing speed (#A), constant current (#B) and pulsed current and decreasing current (#C). One of these should be used for the propulsion system of the Satellite CBERS (China – Brazil Earth Resources Satellite). Welded joints using tubes of commercially pure titanium were obtained with these procedures, which were characterized by means of mechanical an...

  9. Recent development of high efficiency arc welding systems in Japan

    Institute of Scientific and Technical Information of China (English)

    USHIO Masao; SUGITANI Yuji; TANAKA Manabu

    2005-01-01

    The paper describes recent trends to carry forward the automation in welding process in Japanese industries.The present situation on the introduction of computer integrated manufacturing is surveyed and its concept and relation among the constituent subsystems are shown.Also recent developments of arc welding processes and related tools are reviewed.They are as follows.1) Schematic image of the structure of computer integrated manufacturing system (CIM).2) Short descriptions for the trend of introducing CIM system.An example of multi-robot welding system in shipyard,virtual factory,network monitoring of welding quality,clarification of welder's skill.3) Development of high efficiency welding processes.Copper-less wire electrode,tandem large fillet welding,tandem pulse GMA welding,digital wire feeder with new push-pull system,overhead horizontal tandem GMA welding for ship bottom shell,one-sided fillet groove GMA welding for construction machinery,ultra-NGW hot wire GTA process,Al-alloy sheet welding with laser assisted AC pulsed MIG process.

  10. Theoretical model and experimental investigation of current density boundary condition for welding arc study

    OpenAIRE

    Boutaghane, A.; Bouhadef, K.; Valensi, F.; Pellerin, S.; Benkedda, Y.

    2011-01-01

    Abstract This paper presents results of theoretical and experimental investigation of the welding arc in Gas Tungsten Arc Welding (GTAW) and Gas Metal Arc Welding (GMAW) processes. A theoretical model consisting in simultaneous resolution of the set of conservation equations for mass, momentum, energy and current, Ohm's law and Maxwell equation is used to predict temperatures and current density distribution in argon welding arcs. A current density profile h...

  11. Gas Tungsten Arc Welding of Copper and Mild Steel

    OpenAIRE

    Daniel T; Timotius P; Maziar R

    2016-01-01

    In this paper, copper and mild steel were welded using a gas tungsten arc welding (GTAW) process. To determine the weldablity factor, tests are needed to provide information on mechanical strength, potential defects in structure, and nature of failure. Mechanical testing included transverse tensile tests, micro hardness tests, and bend tests. The results for the transverse tensile test revealed failure occurred at the copper heat affected zone (HAZ) with an ultimate tensile strength of 220MPa...

  12. ZVS of arc welding inverter in light load

    Institute of Scientific and Technical Information of China (English)

    Fang Chenfu; Yin Shuyan; Hou Runshi; Yu Ming; Wen Yongping

    2005-01-01

    It is very difficult for arc welding inverter to realize Zero-Voltage-Switching (ZVS) because the load of arc welding inverter changes violently. An improved PS-FB-ZVS-PWM (Phase-Shifted Full-Bridge Zero-Voltage-Switching Pulse-WidthModulation) topology is proposed in this paper. A saturate resonant inductor is in series with the primary side of the transformer, while an auxiliary inductor is in parallel with the secondary side of the transformer to increase reactive current in light load or unload state, so the zero voltage switching of power devices is realized during switching course in light load or unload state.

  13. 30 CFR 77.1112 - Welding, cutting, or soldering with arc or flame; safeguards.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding, cutting, or soldering with arc or... WORK AREAS OF UNDERGROUND COAL MINES Fire Protection § 77.1112 Welding, cutting, or soldering with arc or flame; safeguards. (a) When welding, cutting, or soldering with arc or flame near...

  14. A novel soft-switching twin arc pulse MAG welding inverter

    Institute of Scientific and Technical Information of China (English)

    WANG Zhenmin; XUE Jiaxiang; WANG Fuguang; HUANG Shisheng

    2007-01-01

    The high-speed double wire pulse metal-gas arc (MAG)welding process possesses advantages of automation and high efficiency and quality.Thus,it attracts much more attention nowadays.To meet the requirements of the double wire pulse MAG welding process,a novel double wire pulse MAG welding inverter integrated with technologies,such as soft-switching,double closed loop control,and synchronic control,is produced.A complete performance test was done for the pulsed MAG welding power supply by using a computer testing platform.The results of the experiment indicate that the novel welding inverter has an excellent performance both in the dynamic and the static characteristics.Also,the synchronic control between the master inverter and the slave inverter is reliable.

  15. Numerical analysis of weld pool geometry in globular-transfer gas metal arc welding

    Institute of Scientific and Technical Information of China (English)

    XU Guoxiang; WU Chuansong

    2007-01-01

    The weld pool geometry and its dimension in the globular-transfer mode during gas metal arc welding (GMAW) were numerically analyzed by using the thermal conduction model,which considered the influence of the deformation of weld pool surface on heat flow in the quasi-steady state. According to the features of the globular-transfer mode,the additional heat energy from molten metal droplets was treated as a plane or volumetric heat source term to correspond to different welding conditions.The weld pool surface profile was predicted while considering the effect of droplet impinge-ment on the depression of the weld pool.The bead-on-plate GMAW experiments were performed under different welding conditions to validate the model of numerical analysis.It has been found that the predicted results agree well with the measured ones.

  16. Characterization of titanium welded joints by the orbital gas tungsten arc welding process for aerospace application

    Directory of Open Access Journals (Sweden)

    José A. Orlowski de Garcia

    2010-08-01

    Full Text Available In this work, three welding programs for orbital gas tungsten arc welding (GTAW, previously developed, were used, using pulsed current and increasing speed (#A, constant current (#B and pulsed current and decreasing current (#C. One of these should be used for the propulsion system of the Satellite CBERS (China – Brazil Earth Resources Satellite. Welded joints using tubes of commercially pure titanium were obtained with these procedures, which were characterized by means of mechanical and metallographic tests. The obtained results showed that the three welding procedures produce welded joints free of defects and with adequate shape. Although small differences on mechanical properties and on microstructure have been observed, the three welding programs attained compatible results with international standards used in the aerospace segment. The welding program #B, due to the reduced heat input used, was considered to obtain slightly advantage over the others.

  17. Immunotoxicology of arc welding fume: worker and experimental animal studies.

    Science.gov (United States)

    Zeidler-Erdely, Patti C; Erdely, Aaron; Antonini, James M

    2012-01-01

    Arc welding processes generate complex aerosols composed of potentially hazardous metal fumes and gases. Millions of workers worldwide are exposed to welding aerosols daily. A health effect of welding that is of concern to the occupational health community is the development of immune system dysfunction. Increased severity, frequency, and duration of upper and lower respiratory tract infections have been reported among welders. Specifically, multiple studies have observed an excess mortality from pneumonia in welders and workers exposed to metal fumes. Although several welder cohort and experimental animal studies investigating the adverse effects of welding fume exposure on immune function have been performed, the potential mechanisms responsible for these effects are limited. The objective of this report was to review both human and animal studies that have examined the effect of welding fume pulmonary exposure on local and systemic immune responses. PMID:22734811

  18. Numerical investigations of arc behaviour in gas metal arc welding using ANSYS CFX

    Science.gov (United States)

    Schnick, M.; Fuessel, U.; Hertel, M.; Spille-Kohoff, A.; Murphy, A. B.

    2011-06-01

    Current numerical models of gas metal arc welding (GMAW) are trying to combine magnetohydrodynamics (MHD) models of the arc and volume of fluid (VoF) models of metal transfer. They neglect vaporization and assume an argon atmosphere for the arc region, as it is common practice for models of gas tungsten arc welding. These models predict temperatures above 20 000 K and a temperature distribution similar to tungsten inert gas (TIG) arcs. However, current spectroscopic temperature measurements in GMAW arcs demonstrate much lower arc temperatures. In contrast to TIG arcs they found a central local minimum of the radial temperature distribution. The paper presents a GMAW arc model that considers metal vapour and which is in a very good agreement with experimentally observed temperatures. Furthermore, the model is able to predict the local central minimum in the radial temperature and the radial electric current density distributions for the first time. The axially symmetric model of the welding torch, the work piece, the wire and the arc (fluid domain) implements MHD as well as turbulent mixing and thermal demixing of metal vapour in argon. The mass fraction of iron vapour obtained from the simulation shows an accumulation in the arc core and another accumulation on the fringes of the arc at 2000 to 5000 K. The demixing effects lead to very low concentrations of iron between these two regions. Sensitive analyses demonstrate the influence of the transport and radiation properties of metal vapour, and the evaporation rate relative to the wire feed. Finally the model predictions are compared with the measuring results of Zielińska et al.

  19. Argon arc welding of 12Kh18N10T tubes with constricted arc controlled by magnetic fields

    International Nuclear Information System (INIS)

    Agon arc welding of 12Kh18N10T steel pipes by compressed magneto-monitored arc is reported. The arc and the movement of metal in the bath has been performed by simultaneous application of a stationary and a variable magnetic field. The method provides for 2-2.5 times quicker welding thanks to better impact of the plasma flow on the edges being welded

  20. Analysis of hybrid Nd:Yag laser-MAG arc welding processes.

    OpenAIRE

    Le Guen, Emilie; Fabbro, Rémy; CARIN, Muriel; Coste, Frédéric; LE MASSON, Philippe

    2011-01-01

    In the hybrid laser-arc welding process, a laser beam and an electric arc are coupled in order to combine the advantages of both processes: high welding speed, low thermal load and high depth penetration thanks to the laser; less demanding on joint preparation/fit-up, typical of arc welding. So the hybrid laser-MIG/MAG (Metal Inert or Active Gas) arc welding has very interesting properties: the improvement of productivity results in higher welding speeds, thicker welded materials, joint fit-u...

  1. Experimental investigations of the arc MIG-MAG welding

    International Nuclear Information System (INIS)

    The type of the applied shielding gas has a strong influence on quality of the welding process. In particular, increase of the percentage of carbon dioxide in argon, causes increase of the transition current value from the globular to spray mode of metal transfer. Observations by fast camera allows to better characterize the arc column shape in the different working modes. The spectroscopic diagnostic of the welding arc is also necessary to understand the observed changes in the mode of droplet transfer. The use of an original diagnostic method allows to estimate the temperature and the electronic density distributions in the plasma without hypothesis on its equilibrium state. Results of this work seem to show that the observed effects could be linked to the microstructural modifications of the anode tip during the MIG-MAG welding process as a function of the gas composition, and especially to the existence and disappearance of an insulating oxide 'gangue' at the wire extremity

  2. Study on weld formation in a novel rotating arc horizontal GMAW

    Institute of Scientific and Technical Information of China (English)

    Guo Ning; Lin Sanbao; Fan Chenglei; Zhang Yaqi; Yang Chunli

    2009-01-01

    A novel rotating arc horizontal welding process was developed for solving the sagging of the molten pool which bottlenecks the application and the development of the horizontal welding. The principle of the effect of the rotating arc on the molten pool is that the rotating arc process not only can reduce the welding heat input by prolonging the welding path in the same welding distance caused by the arc rotation, but also disperse the arc force to affect the sidewall periodically to support the molten metal near the upper sidewall. The effects of the rotating speed and arc voltage on the weld formation were studied.The results indicate that there is an appropriate range of the rotating speed and the arc voltage to obtain the defect free horizontal welding.

  3. Spectral characteristics of arc plasma during laser-arc double-sided welding for aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Kezhao Zhang; Zhenglong Lei; Xianglong Wang; Yanbin Chen; Yaobang Zhao

    2015-01-01

    In laser-arc double-sided welding,the spectral characteristics of the arc plasma are calculated and analyzed by spectroscopic diagnosis.The results show that,compared with conventional tungsten inert gas (TIG) welding,the introduction of a laser changes the physical characteristics of the arc plasma regardless of whether laser plasma penetration takes place,and that the influence of the laser mainly affects the near-anode region of the arc.When the laser power is relatively low,the arc column tends to compress,and the arc spectral characteristics show no significant difference.When the arc root constricts,compared with pure TIG arc,the electron density increases by ~2.7 times and the electron temperature decreases by ~3000 K.When the arc column expands,the intensities of spectral lines of both the metal and Ar atoms are the strongest.But it is also observed that the electron density reduces,whereas there is no obvious decrease of electron temperature.

  4. Numerical and experimental study of heat transfers in an arc plasma. Application to TIG arc welding

    International Nuclear Information System (INIS)

    The arc welding is used for many industrial applications, especially GTA welding. Given the excellent quality of the produced welds, GTA welding is used for the majority of the interventions (repairs, joined sealing) on the French nuclear park. This work is part of a project carried out by EDF R and D which aims to simulate the whole process and builds a tool able to predict the welds quality. In this study, we focus on the development of a predictive model of the exchanged heat flux at the arc - work piece interface, responsible of the work piece fusion. The modeling of the arc plasma using the electric module of the hydrodynamics software Code Saturne R developed by EDF R and D is required. Two types of experimental tests are jointly carried out to validate this numerical model: i) on density and temperature measurements of plasma by atomic emission spectroscopy and ii) on the evaluation of the heat transfers on the work piece surface. This work also aims at demonstrate that the usual method of using an equivalent thermal source to model the welding process, can be replaced by our plasma model, without the numerous trials inherent to the usual method. (author)

  5. Study on the Autocontrol of Stud Plunge Depth in Stepping Arc Stud Welding

    OpenAIRE

    Qiang Chi; Jianxun Zhang; Youquan Zhang

    2006-01-01

    Stud plunge depth is one of the important welding conditions in arc stud welding. With the analysis of the stud plunge process, the control of stud plunge depth in the stepping arc stud welding was studied. The extrusion pressure between the stud and the workpiece during welding process is acted as the controlled variable. And a control system based on a displacement sensor was developed. It is indicated from the welding test results that the autocontrol of stud plunge depth using displacemen...

  6. Characterization of magnetically impelled arc butt welded T11 tubes for high pressure applications

    OpenAIRE

    R. Sivasankari; V. Balusamy; P.R. Venkateswaran; G. Buvanashekaran; K Ganesh Kumar

    2015-01-01

    Magnetically impelled arc butt (MIAB) welding is a pressure welding process used for joining of pipes and tubes with an external magnetic field affecting arc rotation along the tube circumference. In this work, MIAB welding of low alloy steel (T11) tubes were carried out to study the microstructural changes occurring in thermo-mechanically affected zone (TMAZ). To qualify the process for the welding applications where pressure could be up to 300 bar, the MIAB welds are studied with variations...

  7. On-line control of surface contamination during gas tungsten arc welding

    International Nuclear Information System (INIS)

    The objective of this research is to apply infrared sensing techniques, artificial intelligence, and robotics to improve the welding process by on-line identification and mitigation of weld plate surface contamination. A method of in-process detection of surface contaminants during the gas tungsten arc welding of steel plate has been developed, and rudimentary corrective actions have been implemented to demonstrate closed-loop control. The study employed on-line IR sensing techniques to dynamically monitor the thermal field in front of the molten pool during the welding process. Changes in thermal pattern and in the area under thermal scans taken perpendicular to the weld seam were then used by the controlling computer to identify undesirable surface contaminants. Appropriate corrective actions were generated and employed to displace the contaminants from the welding path. A computer routine was developed that recognized changes in the thermal patterns due to surface contaminants and implemented corrective procedures. The results of this study will aid in the elimination of weld defects due to surface contamination and hence will increase the reliability and productivity of the welding process

  8. ATOM PROBE MICROANALYSIS OF WELD METAL IN A SUBMERGED ARC WELDED CHROMIUM-MOLYBDENUM STEEL

    OpenAIRE

    Josefsson, B.; Kvist, A.; Andrén, H.

    1987-01-01

    A submerged arc welded 2.25Cr - 1Mo steel has been investigated using electron microscopy and atom probe field ion microscopy. The bainitic microstructure of the as-welded steel consisted of ferrite and martensite. During heat treatment at 690°C the martensite transformed to ferrite and cementite and needle-shaped (Cr,Mo)2C carbides precipitated. Together with a substantial decrease in dislocation density, this resulted in an improvement of the toughness.

  9. CO2 laser-micro plasma arc hybrid welding for galvanized steel sheets

    Institute of Scientific and Technical Information of China (English)

    C. H. KIM; Y. N. AHN; J. H. KIM

    2011-01-01

    A laser lap welding process for zinc-coated steel has a well-known unsolved problem-porosity formation. The boiling temperature of coated zinc is lower than the melting temperature of the base metal. which is steel. In the autogenous laser welding,the zinc vapor generates from the lapped surfaces expels the molten pool and the expulsion causes numerous weld defects, such as spatters and blow holes on the weld surface and porosity inside the welds. The laser-arc hybrid welding was suggested as an alternative method for the laser lap welding because the arc can preheat or post-heat the weldment according to the arrangement of the laser beam and the arc. CO2 laser-micro plasma hybrid welding was applied to the lap welding of zinc-coated steel with zero-gap.The relationships among the weld quality and process parameters of the laser-arc arrangement, and the laser-arc interspacing distance and arc current were investigated using a full-factorial experimental design. The effect of laser-arc arrangement is dominant because the leading plasma arc partially melts the upper steel sheets and vaporizes or oxidizes the coated zinc on the lapped surfaces.Compared with the result from the laser-TIG hybrid welding, the heat input from arc can be reduced by 40%.

  10. A unified 3D model for an interaction mechanism of the plasma arc, weld pool and keyhole in plasma arc welding

    Science.gov (United States)

    Jian, Xiaoxia; Wu, ChuanSong; Zhang, Guokai; Chen, Ji

    2015-11-01

    A 3D model is developed to perform numerical investigation on the coupled interaction mechanism of the plasma arc, weld pool and keyhole in plasma arc welding. By considering the traveling of the plasma arc along the welding direction, unified governing equations are solved in the whole domain including the torch, plasma arc, keyhole, weld pool and workpiece, which involves different physical mechanisms in different zones. The local thermodynamic equilibrium-diffusion approximation is used to treat the interface between the plasma arc and weld pool, and the volume-of-fluid method is used to track the evolution of the keyhole wall. The interaction effects between the plasma arc, keyhole and weld pool as well as the heat, mass and pressure transport phenomena in the whole welding domain are quantitatively simulated. It is found that when the torch is moving along the joint line, the axis of the keyhole channel tilts backward, and the envelope of molten metal surrounding the keyhole wall inside the weld pool is unsymmetrical relative to the keyhole channel. The plasma arc welding tests are conducted, and the predicted keyhole dimensions and the fusion zone shape are in agreement with the experimentally measured results.

  11. Electrochemical Testing of Gas Tungsten Arc Welded and Reduced Pressure Electron Beam Welded Alloy 22

    International Nuclear Information System (INIS)

    Alloy 22 (N06022) is the material selected for the fabrication of the outer shell of the nuclear waste containers for the Yucca Mountain high-level nuclear waste repository site. A key technical issue in the Yucca Mountain waste package program has been the integrity of container weld joints. The currently selected welding process for fabricating and sealing the containers is the traditional gas tungsten arc welding (GTAW) or TIG method. An appealing faster alternative technique is reduced pressure electron beam (RPEB) welding. Standard electrochemical tests were carried on GTAW and RPEB welds as well as on base metal to determine their relative corrosion behavior in SCW at 90 C (alkaline), 1 M HCl at 60 C (acidic) and 1 M NaCl at 90 C (neutral) solutions. Results show that for all practical purposes, the three tested materials had the electrochemical behavior in the three tested solutions

  12. Gas Tungsten Arc Welding of Copper and Mild Steel

    Directory of Open Access Journals (Sweden)

    Daniel T

    2016-06-01

    Full Text Available In this paper, copper and mild steel were welded using a gas tungsten arc welding (GTAW process. To determine the weldablity factor, tests are needed to provide information on mechanical strength, potential defects in structure, and nature of failure. Mechanical testing included transverse tensile tests, micro hardness tests, and bend tests. The results for the transverse tensile test revealed failure occurred at the copper heat affected zone (HAZ with an ultimate tensile strength of 220MPa. The weld metal produced the highest average hardness value of 173HV. The bend tests revealed small cracks on the surfaces of each bend and the nature of the bend, bent around the copper HAZ. Metallography revealed ferrite (α and copper (ε cellular and dendritic shaped microstructure in the weld metal. Post weld heat treatment (PWHT was attempted to observe if any improvements on strength could be achieved. Tensile and micro hardness tests revealed the copper base metal increased in ductility significantly and in the weld metal slightly increased in ductility

  13. Occupational asthma due to gas metal arc welding on mild steel.

    OpenAIRE

    Vandenplas, O.; Dargent, F.; Auverdin, J. J.; Boulanger, J; Bossiroy, J. M.; Roosels, D.; Vande Weyer, R.

    1995-01-01

    Occupational asthma has been documented in electric arc welders exposed to manual metal arc welding on stainless steel. A subject is described who developed late and dual asthmatic reactions after occupational-type challenge exposure to gas metal arc welding on uncoated mild steel.

  14. Passive Visual Sensing in Automatic Arc Welding

    DEFF Research Database (Denmark)

    Liu, Jinchao

    the weld pool, has also prevented the realization of a closed-loop control system for many years, even though a variety of sensors have been developed. Among all the sensor systems, visual sensors have the advantage of receiving visual information and have been drawn more and more attentions. Typical...... possibilities and thoroughly investigated the development of a passive vision system which is only equipped with a single o-the-shelf CCD camera and optical lters, yet capable of extracting sucient information for the control purpose. From the hardware side, we have studies the selection of proper optical lters...

  15. Numerical Simulation of Current Density Distribution in Keyhole Double-Sided Arc Welding

    Institute of Scientific and Technical Information of China (English)

    Junsheng SUN; Chuansong WU; Min ZHANG; Houxiao WANG

    2004-01-01

    In the double-sided arc welding system (DSAW) composing of PAW+TIG arcs, the PAW arc is guided by the TIG arc so that the current mostly flows through the direction of the workpiece thickness and the penetration is greatly improved. To analyze the current density distribution in DSAW is beneficial to understanding of this process.Considering all kinds of dynamic factors acting on the weldpool, this paper discusses firstly the surface deformation of the weldpool and the keyhole formation in PAW+TIG DSAW process on the basis of the magnetohydrodynamic theory and variation principles. Hence, a model of the current density distribution is developed. Through numerical simulation, the current density distribution in PAW+TIG DSAW process is quantitatively analyzed. It shows that the minimal radius of keyhole formed in PAW+TIG DSAW process is 0.5 mm and 89.5 percent of current flows through the keyhole.

  16. Safety and health for welding. ; Skin and eye protections for arc welding light. Yosetsu no anzen eisei. ; Arc ko kara no me oyobi hifu no hogo

    Energy Technology Data Exchange (ETDEWEB)

    Ogasawara, H. (Fujiki Tekko Co. Ltd., Niigata (Japan))

    1991-09-01

    Arc welding, such as CO {sub 2} arc welding and shielding arc welding, generates welding arc light during the welding work, which is hazardous as it may cause injuries in eyes and skin of a human body. This paper describes the injuries and symptoms caused by this welding arc light, and eye protectors. The lights radiated from welding include ultraviolet rays of 280 mm or less, and are visible and infrared rays. The ultraviolet light is an electromagnetic wave easily absorbable into eyes, causing injuries on the surface layer of a cornea. The light is thought to have some relation with skin cancers. The blue light with wave length from 400 to 570 nm in the visible light is under discussion for its relation with retina injuries. The symptoms of injuries from ultraviolet rays appear in several hours to ten and odd hours after an exposure, while those from the blue light and infrared rays appear much later. The paper also describes the relationship between arc current values used in various arc welding processes and the radiation amount of ultraviolet rays, as well as the ultraviolet ray transmitting rate of filter lenses used for light shielding goggles. 7 refs., 6 figs., 5 tabs.

  17. Keyhole behavior and liquid flow in molten pool during laser-arc hybrid welding

    Science.gov (United States)

    Naito, Yasuaki; Katayama, Seiji; Matsunawa, Akira

    2003-03-01

    Hybrid welding was carried out on Type 304 stainless steel plate under various conditions using YAG laser combined with TIG arc. During arc and laser-arc hybrid welding, arc voltage variation was measured, and arc plasma, laser-induced plume and evaporation spots as well as keyhole behavior and liquid flow in the molten pool were observed through CCD camera and X-ray real-time transmission apparatus. It was consequently found that hybrid welding possessed many features in comparison with YAG laser welding. The deepest weld bead could be produced when the YAG laser beam of high power density was shot on the molten pool made beforehand stably with TIG arc. A keyhole was long and narrow, and its behavior was rather stable inside the molten pool. It was also confirmed that porosity was reduced by the suppression of bubble formation in hybrid welding utilizing a laser of a moderate power density.

  18. A comparative study on welding temperature fields, residual stress distributions and deformations induced by laser beam welding and CO2 gas arc welding

    International Nuclear Information System (INIS)

    Highlights: • The welding distortions induced by laser beam welding and CO2 welding are compared. • Large deformation theory is recommended to simulate welding distortion for thin-plate joint. • The welding deformation of thin plate joint can be reduced using laser beam welding. - Abstract: Welding-induced distortion in thin-plate structure is a serious problem which not only hinders the assembling process but also negatively affects the performance of product. Therefore, how to control welding deformation is a key issue both at design stage and at manufacturing stage. During welding process, there are a number of factors which can significantly affect manufacturing accuracy. Among these factors, the heat input is one of the largest contributors to the final deformation. Generally, when laser beam welding (LBW) is used to join parts the total heat input is far less than that used in a conventional welding method such as gas metal arc welding, so it is expected that LBW can significantly reduce welding distortion especially for thin-plate joints. As a fundamental research, we investigated the welding deformations in low carbon steel thin-plate joints induced by LBW and CO2 gas arc welding by means of both numerical simulation technology and experimental method in the current study. Based on the experimental measurements and simulation results, we quantitatively compared the welding deformation as well as residual stress induced by LBW and those due to CO2 gas arc welding. The results indicate that the out-of-plane deformation of thin-plate joint can be largely reduced if CO2 gas arc welding method is replaced by LBW. Moreover, the numerical results indicate that the residual stresses induced by LBW are superior to those produced by CO2 gas arc welding both in distribution and in magnitude

  19. Measurement of three-dimensional welding torch orientation for manual arc welding process

    International Nuclear Information System (INIS)

    Torch orientation plays an important role in welding quality control for a manual arc welding process. The detection of the torch orientation can facilitate weld monitoring, welder training, and may also open a door to many other interesting and useful applications. Yet, little research has been done in measuring the torch orientation in the manual arc welding process. This paper introduces a torch orientation measurement scheme that can be conveniently incorporated both in a real manual arc welding process and in a welder training system. The proposed measurement employs a miniature wireless inertial measurement unit (WIMU), which includes a tri-axial accelerometer and a tri-axial gyroscope. A quaternion-based unscented Kalman filter (UKF) has been designed to estimate the three-dimensional (3D) torch orientation, in which the quaternion associated with the orientation is included in the state vector, as is the angular rate measured by the gyroscope. In addition, an auto-nulling procedure has been developed where the WIMU drift and measurement noise are captured and adaptively compensated in-line to ensure the measurement accuracy. The performance of the proposed scheme has been evaluated by simulations and welding experiments with different types of processes and fit-ups. The simulation results show that the inclination (x- and y-axes) of the torch has been accurately measured with a root-mean-square error (RMSE) in the order of 0.3°. The major error obtained in the heading (z-axis) measurement has been reduced significantly by the proposed auto-nulling procedure. Statistics from welding experiments indicate the proposed scheme is able to provide a complete 3D orientation measurement with the RMSE in the order of 3°. (paper)

  20. 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.

  1. Computer-based sensing and visualizing of metal transfer mode in gas metal arc welding

    Institute of Scientific and Technical Information of China (English)

    Chen Maoai; Wu Chuansong; Lü Yunfei

    2008-01-01

    Using Xenon lamp lights to overcome the strong interference from the welding arc, a computer-based system is developed to sense and visualize the metal transfer in GMAW. This system combines through-the-arc sensing of the welding current and arc voltage with high speed imaging of the metal transfer. It can simultaneously display the metal transfer processes and waveforms of electrical welding parameters in real-time The metal transfer videos and waveforms of electrical welding parameters can be recorded. Metal transfers under various welding conditions have been investigated with the system developed.

  2. GMAW (Gas Metal Arc Welding) process development for girth welding of high strength pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Rajan, Vaidyanath; Daniel, Joe; Quintana, Marie [The Lincoln Electric Company, Cleveland, OH (United States); Chen, Yaoshan [Center for Reliable Energy Systems (CRES), Dublin, OH (United States); Souza, Antonio [Lincoln Electric do Brasil, Guarulhos, SP (Brazil)

    2009-07-01

    This paper highlights some of the results and findings from the first phase of a consolidated program co-funded by US Department of Transportation Pipeline and Hazardous Materials Safety Administration (PHMSA) and Pipeline Research Council Inc (PRCI) to develop pipe weld assessment and qualification methods and optimize X 100 pipe welding technologies. One objective of the program is to establish the range of viable welding options for X 100 line pipe, and define the essential variables to provide welding process control for reliable and consistent mechanical performance of the weldments. In this first phase, a series of narrow gap girth welds were made with pulsed gas metal arc welding (GMAW), instrumented with thermocouples in the heat affected zone (HAZ) and weld metal to obtain the associated thermal profiles, and instrumented to measure true energy input as opposed to conventional heat input. Results reveal that true heat input is 16%-22% higher than conventional heat input. The thermal profile measurements correlate very well with thermal model predictions using true energy input data, which indicates the viability of treating the latter as an essential variable. Ongoing microstructural and mechanical testing work will enable validation of an integrated thermal-microstructural model being developed for these applications. Outputs from this model will be used to correlate essential welding process variables with weld microstructure and hardness. This will ultimately enable development of a list of essential variables and the ranges needed to ensure mechanical properties are achieved in practice, recommendations for controlling and monitoring these essential variables and test methods suitable for classification of welding consumables. (author)

  3. Electrochemical Testing of Gas Tungsten ARC Welded and Reduced Pressure Electron Beam Welded Alloy 22

    Energy Technology Data Exchange (ETDEWEB)

    S. Daniel Day; Frank M.G. Wong; Steven R. Gordon; Lana L. Wong; Raul B. Rebak

    2006-05-08

    Alloy 22 (N06022) is the material selected for the fabrication of the outer shell of the nuclear waste containers for the Yucca Mountain high-level nuclear waste repository site. A key technical issue in the waste package program has been the integrity of the container weld joints. The currently selected welding process for fabricating and sealing the containers is the traditional gas tungsten arc welding (GTAW) or TIC method. An appealing faster alternative technique is reduced pressure electron beam (RPEB) welding. It was of interest to compare the corrosion properties of specimens prepared using both types of welding techniques. Standard electrochemical tests were carried on GTAW and RPEB welds as well as on base metal (non-welded) to determine their relative corrosion behavior in simulated concentrated water (SCW) at 90 C (alkaline), 1 M HCI at 60 C (acidic) and 1 M NaCl at 90 C (neutral) solutions. Results show that for all practical purposes, the three tested materials had the same electrochemical behavior in the three tested electrolytes.

  4. Electrochemical Testing of Gas Tungsten Arc Welded and Reduced Pressure Electron Beam Welded Alloy 22

    International Nuclear Information System (INIS)

    Alloy 22 (N06022) is the material selected for the fabrication of the outer shell of the nuclear waste containers for the Yucca Mountain high-level nuclear waste repository site. A key technical issue in the waste package program has been the integrity of the container weld joints. The currently selected welding process for fabricating and sealing the containers is the traditional gas tungsten arc welding (GTAW) or TIG method. An appealing faster alternative technique is reduced pressure electron beam (RPEB) welding. It was of interest to compare the corrosion properties of specimens prepared using both types of welding techniques. Standard electrochemical tests were carried on GTAW and RPEB welds as well as on base metal (non-welded) to determine their relative corrosion behavior in simulated concentrated water (SCW) at 90 C (alkaline), 1 M HCl at 60 C (acidic) and 1 M NaCl at 90 C (neutral) solutions. Results show that for all practical purposes, the three tested materials had the same electrochemical behavior in the three tested electrolytes

  5. Weld metal microstructures of hardfacing deposits produced by self-shielded flux-cored arc welding

    International Nuclear Information System (INIS)

    The molten pool weld produced during self-shielded flux-cored arc welding (SSFCAW) is protected from gas porosity arising from oxygen and nitrogen by reaction ('killing') of these gases by aluminium. However, residual Al can result in mixed micro-structures of δ-ferrite, martensite and bainite in hardfacing weld metals produced by SSFCAW and therefore, microstructural control can be an issue for hardfacing weld repair. The effect of the residual Al content on weld metal micro-structure has been examined using thermodynamic modeling and dilatometric analysis. It is concluded that the typical Al content of about 1 wt% promotes δ-ferrite formation at the expense of austenite and its martensitic/bainitic product phase(s), thereby compromising the wear resistance of the hardfacing deposit. This paper also demonstrates how the development of a Schaeffler-type diagram for predicting the weld metal micro-structure can provide guidance on weld filler metal design to produce the optimum microstructure for industrial hardfacing applications.

  6. Development of a process model for intelligent control of gas metal arc welding

    International Nuclear Information System (INIS)

    This paper discusses work in progress on the development of an intelligent control scheme for arc welding. A set of four sensors is used to detect weld bead cooling rate, droplet transfer mode, weld pool and joint location and configuration, and weld defects during welding. A neural network is being developed as the bridge between the multiple sensor set a conventional proportional-integral controller that provides independent control of process variables. This approach is being developed for the gas metal arc welding process. 20 refs., 8 figs

  7. A DYNAMIC HEAT SOURCE MODEL WITH RESPECT TO KEYHOLE EVOLUTION IN PLASMA ARC WELDING%考虑小孔演变的等离子弧焊接动态热源模型及验证

    Institute of Scientific and Technical Information of China (English)

    李岩; 冯妍卉; 张欣欣; 武传松

    2013-01-01

    建立了等离子弧焊接熔池传热、流动和相变的三维数学模型,基于小孔动态演变过程与热源模型的相互耦合作用,研究了焊接熔池内传热和流动的发展过程.开发出随小孔深度动态变化的体积热源模型,上部采用Gauss平面热源,下部采用耦合小孔增长的动态锥体热源.应用体积流函数(VOF)方法追踪小孔的形状尺寸,并将小孔深度作为热源高度参数调控热源分布,从而实现热源模型与小孔变化的动态耦合,获得等离子弧焊接熔池温度场、流场和小孔的动态演变规律.进行了等离子弧焊接的实验测试,验证了焊件横断面熔池形状尺寸和底部小孔的穿孔形状尺寸.%Most of the familiar objects in modern society,from buildings and bridges,to vehicles,computers,and medical devices,could not be produced without the use of welding.Especially,with the rising development of advanced manufacturing industry,such as aircraft and aerospace industries,shipbuilding and marine industries and automotive industries,cost-effective high-efficiency high-quality welding processes are being progressively required for increasing performance requirements and enhancements in product quality.Thus,the plasma arc welding (PAW) provides a means for these process demands by using a high power density heat source.The keyhole effect is commonly recognized as the primary attribute to the deep-penetration welding.Compared to electron beam welding and laser welding,PAW is more cost effective and more tolerant of joint gaps and misalignment.However,the mechanism of keyhole formation in PAW process differs from that in other high power density welding processes.In PAW the keyhole is produced and maintained mainly by the pressure of the plasma arc,rather than by the recoil pressure of the evaporating metal in electron beam and laser welding.Considerable research has been focused on keyhole tracking and effective heat source models for PAW process

  8. Workplace exposure to nanoparticles from gas metal arc welding process

    International Nuclear Information System (INIS)

    Workplace exposure to nanoparticles from gas metal arc welding (GMAW) process in an automobile manufacturing factory was investigated using a combination of multiple metrics and a comparison with background particles. The number concentration (NC), lung-deposited surface area concentration (SAC), estimated SAC and mass concentration (MC) of nanoparticles produced from the GMAW process were significantly higher than those of background particles before welding (P < 0.01). A bimodal size distribution by mass for welding particles with two peak values (i.e., 10,000–18,000 and 560–320 nm) and a unimodal size distribution by number with 190.7-nm mode size or 154.9-nm geometric size were observed. Nanoparticles by number comprised 60.7 % of particles, whereas nanoparticles by mass only accounted for 18.2 % of the total particles. The morphology of welding particles was dominated by the formation of chain-like agglomerates of primary particles. The metal composition of these welding particles consisted primarily of Fe, Mn, and Zn. The size distribution, morphology, and elemental compositions of welding particles were significantly different from background particles. Working activities, sampling distances from the source, air velocity, engineering control measures, and background particles in working places had significant influences on concentrations of airborne nanoparticle. In addition, SAC showed a high correlation with NC and a relatively low correlation with MC. These findings indicate that the GMAW process is able to generate significant levels of nanoparticles. It is recommended that a combination of multiple metrics is measured as part of a well-designed sampling strategy for airborne nanoparticles. Key exposure factors, such as particle agglomeration/aggregation, background particles, working activities, temporal and spatial distributions of the particles, air velocity, engineering control measures, should be investigated when measuring workplace

  9. Optimizing the Pulsed Current Gas Tungsten Arc Welding Parameters

    Institute of Scientific and Technical Information of China (English)

    M. Balasubramanian; V. Jayabalan; V. Balasubramanian

    2006-01-01

    The selection of process parameter in the gas tungsten arc (GTA) welding of titanium alloy was presented for obtaining optimum grain size and hardness. Titanium alloy (Ti-6Al-4V) is one of the most important non-ferrous metals which offers great potential application in aerospace, biomedical and chemical industries,because of its low density (4.5 g/cm3), excellent corrosion resistance, high strength, attractive fracture behaviour and high melting point (1678℃). The preferred welding process for titanium alloy is frequent 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. Many considerations come into the picture and one needs to carefully balance various pulse current parameters to reach an optimum combination. Four factors, five level, central composite, rotatable design matrix were used to optimize the required number of experimental conditions. Mathematical models were developed to predict the fusion zone grain size using analysis of variance (ANOVA) and regression analysis. The developed models were optimized using the traditional Hooke and Jeeve's algorithm. Experimental results were provided to illustrate the proposed approach.

  10. Effect of Submerged Arc Welding Flux Component on Softening Temperature

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Based on simplex algorithm of optimal design, the multicomponent mixture regression model was used to investigate physical properties of submerged arc welding flux. The effect of complex interaction of seven components in agglomerated flux on softening temperature was analyzed. The results indicate that the interaction of MgO-TiO2-CaCO3-Al2O3 increases the softening temperature of flux, but the additions of CaF2 and ZrO2 can decrease the softening temperature.

  11. Optimization of Weld Bead Parameters of Nickel Based Overlay Deposited by Plasma Transferred Arc Surfacing with Adequacy Test

    OpenAIRE

    Bhaskarananda Dasgupta; Pinaky Bhadury

    2014-01-01

    Plasma Transferred Arc surfacing is a kind of Plasma Transferred Arc Welding process. Plasma Transferred Arc surfacing (PTA) is increasingly used in applications where enhancement of wear, corrosion and heat resistance of materials surface is required. The shape of weld bead geometry affected by the PTA Welding process parameters is an indication of the quality of the weld. In this paper the analysis and optimization of weld bead parameters, during deposition of a Nickel based...

  12. Correction factor based double model fuzzy logic control strategy of arc voltage in pulsed MIG welding

    Institute of Scientific and Technical Information of China (English)

    Wu Kaiyuan; Huang Shisheng; Meng Yongmin

    2005-01-01

    According to the feature of arc voltage control in welding steel using pulsed MIG welding, a correction factor based double model fuzzy logic controller (FLC) was developed to realize the arc voltage control by means of arc voltage feedback.When the error of peak arc voltage was great, a coarse adjusting fuzzy logic control rules with correction factor was designed,in the controller, the peak arc voltage was controlled by the wire feeding speed by means of arc voltage feedback. When the error of peak arc voltage was small, a fine adjusting fuzzy logic control rules with correction factor was designed, in this controller, the peak arc voltage was controlled by the background time by means of arc voltage feedback. The FLC was realized in a Look-Up Table ( LUT) method. Experiments had been carried out aiming at implementing the control strategy to control the arc length change in welding process. Experimental results show that the controller proposed enables the consistency of arc length and the stabolity of arc voltage and welding process to be achieved in pulsed MIG welding process.

  13. 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.

  14. Digital control of pulsed gas metal arc welding inverter using TMS320LF2407A

    Institute of Scientific and Technical Information of China (English)

    Wu Kaiyuan; Huang Shisheng; Li Xinglin; Wu Shuifeng

    2008-01-01

    A digital control of pulsed gas metal arc welding inverter was proposed. A control system consisting of analogue parts was replaced with a new digital control implemented in a TMS320LF2407A DSP chip. The design and constructional features of the whole digital control were presented. The resources of the DSP chip were efficiently utilized and the circuits are very concise, which can enhance the stability and reliability of welding inverter. Experimental results demonstrate that the developed digital control has the ability to accomplish the excellent pulsed gas metal arc welding process and the merits of the developed digital control are stable welding process, little spatter and perfect weld appearance.

  15. Vision of the Arc for Quality Documentation and for Closed Loop Control of the Welding Process

    DEFF Research Database (Denmark)

    Kristiansen, Morten; Kristiansen, Ewa; Jensen, Casper Houmann;

    2014-01-01

    For gas metal arc welding a vision system was developed, which was robust to monitor the position of the arc. The monitoring documents the welding quality indirectly and a closed loop fuzzy control was implemented to control an even excess penetration. For welding experiments on a butt......-joint with a V-groove with varying root gapthe system demonstrated increased welding quality compared to the system with no control. The system was implemented with a low cost vision system, which makes the system interesting to apply in industrial welding automation systems....

  16. Modelling of the bead formation during multi pass hybrid laser/gas metal arc welding

    OpenAIRE

    Desmaison, Olivier; Guillemot, Gildas; Bellet, Michel

    2012-01-01

    A three dimensional finite element model has been developed to simulate weld bead formation in multi pass hybrid laser/gas metal arc welding. The model considers both a gas metal arc welding (GMAW) electrode and a laser beam moving along a workpiece. A Eulerian approach is used in which the interface between the metal and the surrounding gas or plasma is defined by a level set function. Therefore heat transfer boundary conditions are applied through a "Continuum Surface Force" model. An origi...

  17. Characterization of magnetically impelled arc butt welded T11 tubes for high pressure applications

    Directory of Open Access Journals (Sweden)

    R. Sivasankari

    2015-09-01

    Full Text Available Magnetically impelled arc butt (MIAB welding is a pressure welding process used for joining of pipes and tubes with an external magnetic field affecting arc rotation along the tube circumference. In this work, MIAB welding of low alloy steel (T11 tubes were carried out to study the microstructural changes occurring in thermo-mechanically affected zone (TMAZ. To qualify the process for the welding applications where pressure could be up to 300 bar, the MIAB welds are studied with variations of arc current and arc rotation time. It is found that TMAZ shows higher hardness than that in base metal and displays higher weld tensile strength and ductility due to bainitic transformation. The effect of arc current on the weld interface is also detailed and is found to be defect free at higher values of arc currents. The results reveal that MIAB welded samples exhibits good structural property correlation for high pressure applications with an added benefit of enhanced productivity at lower cost. The study will enable the use of MIAB welding for high pressure applications in power and defence sectors.

  18. Energy Characterization of Short-Circuiting Transfer of Metal Droplet in Gas Metal Arc Welding

    Science.gov (United States)

    Yi, Luo; Yang, Zhu; Xiaojian, Xie; Rui, Wan

    2015-08-01

    The structure-borne acoustic emission (AE) signals were detected in real time in gas metal arc (GMA) welding and pulse GMA (P-GMA) welding. According to the AE signals, the mode of short-circuiting transfer was analyzed, and the energy gradient and total energy were calculated. The calculation to the AE signals of one metal droplet transfer (MDT) showed that the energy gradient increased with increasing welding heat input not only in GMA welding but also in P-GMA welding. The energy gradient of one MDT in P-GMA welding was higher than that in GMA welding, which indicated that a high energy gradient was the basic reason for the additional vibration energy provided by pulse effect in P-GMA welding. The total energy of AE signals increased with increasing welding heat input not only in GMA welding but also in P-GMA welding. The total energy of AE signals in P-GMA welding was higher than that in GMA welding, which indicated that the additional vibration energy provided by welding pulses was the main cause of the grain structure refining in P-GMA welding. So, the results provided another means to predict the weld grain size and optimize the welding process by AE signals detected in welding.

  19. Influencing the arc and the mechanical properties of the weld metal in GMA-welding processes by additive elements on the wire electrode surface

    Science.gov (United States)

    Wesling, V.; Schram, A.; Müller, T.; Treutler, K.

    2016-03-01

    Under the premise of an increasing scarcity of raw materials and increasing demands on construction materials, the mechanical properties of steels and its joints are gaining highly important. In particular high- and highest-strength steels are getting in the focus of the research and the manufacturing industry. To the same extent, the requirements for filler metals are increasing as well. At present, these low-alloy materials are protected by a copper coating (film coatings on solid wire electrodes for Gas Metal Arc welding. The influences are regarding the stability of the arc, the properties of the weld metal in terms of geometric expression, chemical composition and mechanical properties, the composition of the arc-plasma and the dynamics of the molten metal.

  20. A comparison of residual stresses in multi pass narrow gap laser welds and gas-tungsten arc welds in AISI 316L stainless steel

    OpenAIRE

    Elmesalamy, Ahmed; Francis, John Anthony; LI, Lin

    2014-01-01

    Thick-section austenitic stainless steels have widespread industrial applications, especially in nuclear power plants. The joining methods used in the nuclear industry are primarily based on arc welding processes. However, it has recently been shown that narrow gap laser welding (NGLW) can weld ma- terials with thicknesses that are well beyond the capabilities of single pass autogenous laser welding. The heat input for NGLW is much lower than for arc welding, as are the expected levels of res...

  1. Self-adjusting dynamic characteristics of pulsed MIG welding for aluminum alloys

    Institute of Scientific and Technical Information of China (English)

    包晔峰; 周昀; 吴毅雄; 楼松年

    2004-01-01

    Pulsed MIG welding is suitable for aluminum alloys welding, because spray transfer and excellent profile can be arrived during whole welding current range, and the energy of droplet can be controlled to overcome losing of alloy elements with lower melting and steam point by controlling pulse current and pulse time. Because of the special physic properties of aluminum alloys, there are different requirements for pulsed MIG welding between starting arc short circuit and drop transfer short circuit, pulse period and base period. In order to satisfy the need of aluminum alloys MIG welding, self-adjusting dynamic characteristics are designed to output different dynamic characteristics in different welding startes. The self-adjusting dynamic characteristics of pulsed MIG welding are achieved through a short circuit controller and a dynamic electronic inductor. The welding machine(AL-MIG 350) with self-adjusting dynamic characteristics has a high rate of successfully starting arc up to 96%, and the short circuit time during transfer is less than 1 ms, in the mean time, the arc is stiffness, spatter is low and weld appearance is good.

  2. Comparative study on transverse shrinkage, mechanical and metallurgical properties of AA2219 aluminium weld joints prepared by gas tungsten arc and gas metal arc welding processes

    OpenAIRE

    Arunkumar, S.; P.Rangarajan; K. Devakumaran; P.Sathiya

    2015-01-01

    Aluminium alloy AA2219 is a high strength alloy belonging to 2000 series. It has been widely used for aerospace applications, especially for construction of cryogenic fuel tank. However, arc welding of AA2219 material is very critical. The major problems that arise in arc welding of AA2219 are the adverse development of residual stresses and the re-distribution as well as dissolution of copper rich phase in the weld joint. These effects increase with increase in heat input. Thus, special atte...

  3. Fatigue assessment of a double submerged arc welded gas pipeline

    Energy Technology Data Exchange (ETDEWEB)

    Fazzini, Pablo; Otegui, Jose Luis [Universidad Nacional Mar del Plata, Mar del Plata (Argentina). Instituto de Ciencia y Tecnologia de Materiales (INTEMA); Teutonico, Mauricio; Manfredi, Carlos [GIE S.A., Mar del Plata (Argentina)

    2005-07-01

    An uncommon blowout in a 24'' diameter, 7 mm thick API 5L X52 gas pipeline was due to fracture at the longitudinal double submerged arc weld. Oddly enough for gas pipelines, it was found that fatigue cracks had propagated from a large embedded weld defect of lack of fusion resulting from severe geometrical mismatch between inner and outer weld passes. What makes this failure particularly interesting is that: previous in line inspections failed to detect any defect, no evidence of third party damage was found, and very few large pressure cycles had been recorded during the last 5 years of service, which were believed to be representative of the entire service life of the pipeline. Fatigue tests were carried out to characterize propagation of fatigue cracks in weld metal, it was found that a large Paris exponent made the few large amplitude cycles most contributing to crack propagation. Crack growth path and striation patterns were studied. Fatigue growth was modelled by integrating experimental results and by extrapolating striation spacing in the fracture surface of the failed pipe. Crack growth path and striation patterns were studied. It was found that microstructure discontinuities govern propagation at low {delta}K, but one striation per cycle was produced at large {delta}K, due to a mostly ductile propagation mode. Fatigue growth was modelled by integrating experimental results and by extrapolating striation spacing in the fracture surface of the failed pipe. It was found that in the early life of the line many more large pressure cycles than expected had occurred. Good correspondence between predicted and actual fatigue lives was in this way obtained (author)

  4. Fluid Flow Behaviour under Different Gases and Flow Rate during Gas Metal Arc Welding

    OpenAIRE

    Jaison Peter

    2013-01-01

    Gas metal arc welding (GMAW) is a highly efficient and fast process for fabricating high quality weld. High quality welds are fabricated by proper selection of consumable includes gas and filler metals. The optimum flow rate of gas will ensure the proper quality of weld. In this project, a fluid flow behavior of different flow rate is modeled and the change quality will be studied.

  5. Sub-arc narrow gap welding of Atucha 2 RPV closure head

    International Nuclear Information System (INIS)

    Narrow gap technology was used for reasons of design and fabrication when welding the closure-head dome to its flange. Preliminary tests had yielded the necessary improvements of the well-proven sub-arc practice. New facilities had to be developed for welding proper and for the accompanying machining work (finishing in the narrow gap). Special measures were adopted for monitoring the welding process and for recording the welding parameters. The new method was tried out on several large test coupons before welding of the final product was started. No difficulties were encountered during the welding job. Fabrication of the closure head is shown in a short film sequence. (orig.)

  6. Submerged arc narrow gap welding of the steel DIN 20MnMoNi55

    International Nuclear Information System (INIS)

    The methodology for submerged arc narrow gap welding for high thickness rolled steel DIN 20MnMoNi55 was developed, using din S3NiMo1 04 mm and 05 mm wires, and DIN 8B435 flux. For this purpose, submerged arc narrow gap welded joints with 50 mm and 120 mm thickness were made aiming the welding parameters optimization and the study of the influence of welding voltage, wire diameter and wire to groove face distance on the operational performance and on the welded joint quality, specially on the ISO-V impact toughness. These welded joints were checked by non-destructive mechanical and metallographic tests. Results were compared with those obtained by one 120 mm thickness submerged arc conventional gap welded joint, using the same base metal and consumables (05 mm wire). The analysis of the results shows that the increasing of the wire to groove face distance and the welding voltage increases the hardness and the ISO-V impact toughness of the weld metal. It shows that the reduction of the gap angle is the main cause for the obtained of a heat affected zone free from coarse grains, the reduction of the welding voltage, the increasing of the wire to groove face distance, and the grounding optimization also contribute for that. It was also concluded that the quality and the execution complexity level of a narrow gap welded joint are identical to a conventional gap welded joint. (author)

  7. Effect of Autogenous Arc Welding Processes on Tensile and Impact Properties of Ferritic Stainless Steel Joints

    Institute of Scientific and Technical Information of China (English)

    A K Lakshminarayanan; K Shanmugam; V Balasubramanian

    2009-01-01

    The effect of autogeneous arc welding processes on tensile and impact properties of ferritic stainless steel conformed to AISI 409M grade is studied.Rolled plates of 4 mm thickness have been used as the base material for preparing single pass butt welded jointa.Tensile and impact properties,microhardness,microstructure,and fracture surface morphology of continuous current gas tungsten arc welding (CCGTAW),pulsed current gas tungsten arc welding (PCGTAW),and plasma arc welding (PAW) joints are evaluated and the results are compared.It is found that the PAW joints of ferritic stainless steel show superior tensile and impact properties when compared with CCGTAW and PCGTAW joints,and this is mainly due to lower heat input,finer fusion zone grain diameter,and higher fusion zone hardness.

  8. System design of welding dynamic displacement measurement using laser ESPI

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Based on the advantages of electronic speckle pattern interferometry(ESPI), such as non-contact, high precision, strong parasitic light resistance, and full-field measurement, a system for measuring welding dynamic displacement fields using ESPI was designed. The system consists of a 70mW He-Ne laser source, an optical path system, a computer-assisted frame grabber and a processing system. By measuring dynamic displacement fields on one LY2 aluminum alloy plate during an argon arc point welding, it can be proved that using ESPI to measure welding dynamic displacement fields is fully feasible, and this method can offer a solid experimental base for the structure mechanics.

  9. Improvements of the welding performance of plasma arcs by a superimposed fibre laser beam

    Science.gov (United States)

    Mahrle, Achim; Rose, Sascha; Schnick, Michael; Pinder, Thomas; Beyer, Eckhard; Füssel, Uwe

    2012-03-01

    Details and results of experimental investigations of a laser-supported plasma arc welding process are presented. The particular feature of the realized experimental set-up is the coaxial arrangement of a single-mode fibre laser beam through a hollow tungsten electrode in combination with a modified plasma welding torch. The analysis of the welding capabilities of the combined laser-arc source comprises high-speed video recordings of the arc shape and size, corresponding simultaneous measurements of the arc voltage as well as an evaluation of the resultant weld seam geometries. Results of welding trials on different types of steel and aluminum alloys are discussed. The corresponding investigations reveal that a fibre laser beam with a wavelength of 1.07 microns can have a crucial impact on the arc and welding characteristics for both categories of materials even at very low laser power output levels. Beneficial effects are especially observed with high welding speeds. In that particular case the arc root and therefore arc column can be substantially stabilized and guided by the laser-induced hot spot.

  10. Cracking generated by arc welding; La fissuration consecutive a l'operation de soudage a l'arc

    Energy Technology Data Exchange (ETDEWEB)

    Carpreau, J.M. [LaMSID UMR EDF-CNRS-CEA 2832, 78 - Chatou (France)

    2010-07-01

    During welding, rapid localized heat transients lead to thermal cycles, resulting in changes in the local metallurgy and mechanical loading of the components to be joined. Depending on the materials, these changes may generate cracks, making the weld structure unable to resist in-service loading. Analysis of various cracking mechanisms showed the role of the thermomechanical loading of the weld or HAZ during cooling after arc welding. Hence, prediction of cracking is based on the calculation of the thermomechanical stress, which often gives an estimated range, or from a mechanistically-based phenomenological approach. (author)

  11. High-power laser and arc welding of thorium-doped iridium alloys

    International Nuclear Information System (INIS)

    The arc and laser weldabilities of two Ir-0.3% W alloys containing 60 and 200 wt ppM Th have been investigated. The Ir-.03% W alloy containing 200 wt ppM Th is severely prone to hot cracking during gas tungsten-arc welding. Weld metal cracking results from the combined effects of heat-affected zone liquation cracking and solidification cracking. Scanning electron microscopic analysis of the fractured surface revealed patches of low-melting eutectic. The cracking is influenced to a great extent by the fusion zone microstructure and thorium content. The alloy has been welded with a continuous-wave high-power CO2 laser system with beam power ranging from 5 to 10 kW and welding speeds of 8 to 25 mm/s. Successful laser welds without hot cracking have been obtained in this particular alloy. This is attributable to the highly concentrated heat source available in the laser beam and the refinement in fusion zone microstructure obtained during laser welding. Efforts to refine the fusion zone structure during gas tungsten-arc welding of Ir-0.3 % W alloy containing 60 wt ppM Th were partially successful. Here transverse arc oscillation during gas tungsten-arc welding refines the fusion zone structure to a certain extent. However, microstructural analysis of this alloy's laser welds indicates further refinement in the fusion zone microstructure than in that from the gas tungsten-arc process using arc oscillations. The fusion zone structure of the laser weld is a strong function of welding speed

  12. Development of ultra-narrow gap welding with constrained arc by flux band

    Institute of Scientific and Technical Information of China (English)

    Zhu Liang; Zheng Shaoxian; Chen Jianhong

    2006-01-01

    Narrow gap welding has merits of lower residual stress and distortion, and superior mechanical properties of joints.A major problem of this process is the lack of fusion in sidewalls, hence many methods of weaving arc have been developed to increase heating effect of arc to the sidewalls. In this work, a new approach without weaving arc is attempted to ensure the penetration of sidewall, and ultra-narrow gap welding with the gap of less than 5 mm was executed successfully. In this approach, the width of gap is decreased further, so that the sidewalls are made within range of arc heating to obtain the enough heat. Inorder to prevent the arc from being attracted by sidewall and going up alongthe sidewalls, two pieces of flux bands consisting of the specified aggregates are adhered to the sidewalls to constrain the arc. In addition, when flux band being heated by the arc, slag and gases are formed to shield the arc and the weld pool. This technique was tested on the welding experiment of pipeline steel with thickness of 20 mm. The involved welding parameters were obtained, that is, the width of gap is 4 mm, the welding current 250 A, and the heat input 0. 5 k J/mm, the width of heat-affected zone is 1 - 2mm.

  13. Microstructure and properties of Mg/Al joint welded by gas tungsten arc welding-assisted hybrid ultrasonic seam welding

    International Nuclear Information System (INIS)

    Graphical abstract: Gas tungsten arc welding (GTAW) was introduced into ultrasonic seam welding of Mg and Al dissimilar metals for the first time as shown in (a). The preceding GTAW can preheat the sheet metal to enhance the weldability. Without improving the ultrasonic power, the direct joining of 1 mm thick Al and Mg alloys sheets was accomplished and the maximum lap shear strength was 1 kN at a GTAW current of 30 A, approximately 40% of AZ31B Mg alloy base metal, as shown in (b). - Highlights: • Mg and Al were joined in solid state by hybrid ultrasonic seam welding. • The preceding GTAW heat source enhanced the acoustic bonding effect. • The maximum lap shear strength was 1 kN at a GTAW current of 30 A. - Abstract: A novel gas tungsten arc welding (GTAW) assisted hybrid ultrasonic seam welding MgAZ31B and Al6061 alloy sheets with satisfactory joint strength were successfully achieved using a previous GTAW preheating heat source. The preceding GTAW reduced the sheet hardness but enhanced the acoustic softening effect and materials plasticity. Therefore, the direct joining of 1 mm thick MgAZ31B and Al6061 alloy sheets can be obtained without improving the ultrasonic power. The effect of GTAW current on the microstructure and mechanical properties was investigated. The tensile shear strength of the joint increased with GTAW current up to a maximum strength and then decreased dramatically with higher GTAW current. The maximum lap shear strength was 1 kN at a GTAW current of 30 A, approximately 40% of AZ31B Mg alloy base metal. The failure occurred by interface fracture mode, and the fracture patterns exhibited brittle fracture mode with cleavage facet feature

  14. Formation Mechanism of Inclusion in Self-Shielded Flux Cored Arc Welds

    Institute of Scientific and Technical Information of China (English)

    YU Ping; LU Xiao-sheng; PAN Chuan; XUE Jin; LI Zheng-bang

    2005-01-01

    The formation mechanism of inclusion in welds with different aluminum contents was determined based on thermodynamic equilibrium in self-shielded flux cored arc welds. Inclusions in welds were systematically studied by optical microscopy, scanning microscopy and image analyzer. The results show that the average size and the contamination rate of inclusions in low-aluminum weld are lower than those in high-aluminum weld. Highly faceted AlN inclusions with big size in the high-aluminum weld are more than those in low-aluminum weld. As a result,the low temperature impact toughness of low-aluminum weld is higher than that of high-aluminum weld. Finally,the thermodynamic analysis indicates that thermodynamic result agrees with the experimental data.

  15. Selection of arc welding parameters of micro alloyed HSLA steel

    OpenAIRE

    M. Dunđer; Ž. Ivandić; Samardžić, I.

    2008-01-01

    In order to ensure performance reliability of a welded product, its quality has to be ensured by proper setting of welding parameters and welding cycle. A quality weld – a weld with no manufacturing, structural or geometric flaws, i.e. with necessary mechanical properties - is achieved only by correct parameter definition and adherence. The knowledge of various effects and relations between welding parameters and their repetition enable an optimal choice of welding parameters.

  16. Selection of arc welding parameters of micro alloyed HSLA steel

    Directory of Open Access Journals (Sweden)

    M. Dunđer

    2008-10-01

    Full Text Available In order to ensure performance reliability of a welded product, its quality has to be ensured by proper setting of welding parameters and welding cycle. A quality weld – a weld with no manufacturing, structural or geometric flaws, i.e. with necessary mechanical properties - is achieved only by correct parameter definition and adherence. The knowledge of various effects and relations between welding parameters and their repetition enable an optimal choice of welding parameters.

  17. Simulation of droplet transfer process and current waveform control of CO2 arc welding

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A simulation system used in the arc welding short-circuit transfer process and current waveform control process was developed in this paper. The simulation results are basically consistent with welding technical experiments. The simulation system can be used to simulate and test the current waveform control parameters with welding variables. By this simulation system, the influence regularities of the current waveform control parameters in the CO2 arc welding droplet short-circuit transfer process can be got. Moreover, the basic mode of real-time current waveform control can be also established by the simulation testing.

  18. Study on arc and laser powers in the hybrid welding of AA5754 Al-alloy

    International Nuclear Information System (INIS)

    Highlights: • 5754 Al-alloy weldability with a hybrid welding source was assessed. • Weld porosity sensitiveness to laser and arc powers was demonstrated. • Microstructure, residual stress and the mechanical properties were evaluated. • The best levels of welding parameters were given in the investigated range. - Abstract: In this paper a new generation of fiber laser assisted by a MIG source was used to weld AA5754-H111 aluminum alloy in 3 mm thick butt configuration. The effects of laser and arc powers on the weld geometry and properties were studied. Weld geometry and porosity were measured. The microstructure was investigated by optical microscope and Vickers micro-hardness was taken. The residual stress close to the heat affected zone was measured by the incremental hole-drilling method. Eventually, the tensile test was conducted in order to compare the mechanical properties of the weld with those of the parent metal. For the first time the sensitiveness of the hybrid welding of the 5754 aluminum alloy to the arc and laser powers was demonstrated. Higher laser power favored the stability of the process and provided good structural and geometrical properties of the weld. Further investigation can be performed in order to optimize the weld soundness and the energy efficiency of hybrid welding an aluminum alloy using a fiber laser

  19. Stainless steel submerged arc weld fusion line toughness

    International Nuclear Information System (INIS)

    This effort evaluated the fracture toughness of austenitic steel submerged-arc weld (SAW) fusion lines. The incentive was to explain why cracks grow into the fusion line in many pipe tests conducted with cracks initially centered in SAWS. The concern was that the fusion line may have a lower toughness than the SAW. It was found that the fusion line, Ji. was greater than the SAW toughness but much less than the base metal. Of greater importance may be that the crack growth resistance (JD-R) of the fusion line appeared to reach a steady-state value, while the SAW had a continually increasing JD-R curve. This explains why the cracks eventually turn to the fusion line in the pipe experiments. A method of incorporating these results would be to use the weld metal J-R curve up to the fusion-line steady-state J value. These results may be more important to LBB analyses than the ASME flaw evaluation procedures, since there is more crack growth with through-wall cracks in LBB analyses than for surface cracks in pipe flaw evaluations

  20. Stainless steel submerged arc weld fusion line toughness

    Energy Technology Data Exchange (ETDEWEB)

    Rosenfield, A.R.; Held, P.R.; Wilkowski, G.M. [Battelle, Columbus, OH (United States)

    1995-04-01

    This effort evaluated the fracture toughness of austenitic steel submerged-arc weld (SAW) fusion lines. The incentive was to explain why cracks grow into the fusion line in many pipe tests conducted with cracks initially centered in SAWS. The concern was that the fusion line may have a lower toughness than the SAW. It was found that the fusion line, Ji. was greater than the SAW toughness but much less than the base metal. Of greater importance may be that the crack growth resistance (JD-R) of the fusion line appeared to reach a steady-state value, while the SAW had a continually increasing JD-R curve. This explains why the cracks eventually turn to the fusion line in the pipe experiments. A method of incorporating these results would be to use the weld metal J-R curve up to the fusion-line steady-state J value. These results may be more important to LBB analyses than the ASME flaw evaluation procedures, since there is more crack growth with through-wall cracks in LBB analyses than for surface cracks in pipe flaw evaluations.

  1. Theoretical model and experimental investigation of current density boundary condition for welding arc study

    Science.gov (United States)

    Boutaghane, A.; Bouhadef, K.; Valensi, F.; Pellerin, S.; Benkedda, Y.

    2011-04-01

    This paper presents results of theoretical and experimental investigation of the welding arc in Gas Tungsten Arc Welding (GTAW) and Gas Metal Arc Welding (GMAW) processes. A theoretical model consisting in simultaneous resolution of the set of conservation equations for mass, momentum, energy and current, Ohm's law and Maxwell equation is used to predict temperatures and current density distribution in argon welding arcs. A current density profile had to be assumed over the surface of the cathode as a boundary condition in order to make the theoretical calculations possible. In stationary GTAW process, this assumption leads to fair agreement with experimental results reported in literature with maximum arc temperatures of ~21 000 K. In contrast to the GTAW process, in GMAW process, the electrode is consumable and non-thermionic, and a realistic boundary condition of the current density is lacking. For establishing this crucial boundary condition which is the current density in the anode melting electrode, an original method is setup to enable the current density to be determined experimentally. High-speed camera (3000 images/s) is used to get geometrical dimensions of the welding wire used as anode. The total area of the melting anode covered by the arc plasma being determined, the current density at the anode surface can be calculated. For a 330 A arc, the current density at the melting anode surface is found to be of 5 × 107 A m-2 for a 1.2 mm diameter welding electrode.

  2. High power fiber laser arc hybrid welding of AZ31B magnesium alloy

    International Nuclear Information System (INIS)

    Highlights: ► Fiber laser–metal inert gas arc hybrid welding of AZ31B Mg alloy was developed. ► The maximum tensile strength efficiency of 5 mm thick welds is up to 109%. ► Grain size of fusion zone and width of PMZ both increase with heat input. ► Hall–Petch relationship between microhardness and grain size is obtained. ► Strength difference between 5 mm and 8 mm thick welds is summarized and discussed. -- Abstract: High power fiber laser–metal inert gas arc hybrid welding of AZ31B magnesium alloy was studied. The fusion zone consisted of hexagonal dendrites, where the secondary particle of Al8Mn5 was found at the center of dendrite as a nucleus. Within hybrid weld, the arc zone had coarser grain size and wider partial melted zone compared with the laser zone. The tensile results showed the maximum strength efficiency of 5 mm thick welds was up to 109%, while that of 8 mm thick welds was only 88%. The fracture surface represented a ductile–brittle mixed pattern characterized by dimples and quasi-cleavages. On the fracture surface some metallurgical defects of porosity and MgO inclusions around with secondary cracks were observed. Meanwhile, a strong link between the joint strength and weld porosity were demonstrated by experimental results, whose relevant mechanism was discussed by the laser–arc interaction during hybrid welding.

  3. Reflection of illumination laser from gas metal arc weld pool surface

    International Nuclear Information System (INIS)

    The weld pool is the core of the welding process where complex welding phenomena originate. Skilled welders acquire their process feedback primarily from the weld pool. Observation and measurement of the three-dimensional weld pool surface thus play a fundamental role in understanding and future control of complex welding processes. To this end, a laser line is projected onto the weld pool surface in pulsed gas metal arc welding (GMAW) and an imaging plane is used to intercept its reflection from the weld pool surface. Resultant images of the reflected laser are analyzed and it is found that the weld pool surface in GMAW does specularly reflect the projected laser as in gas tungsten arc welding (GTAW). Hence, the weld pool surface in GMAW is also specular and it is in principle possible that it may be observed and measured by projecting a laser pattern and then intercepting and imaging the reflection from it. Due to high frequencies of surface fluctuations, GMAW requires a relatively short time to image the reflected laser

  4. Structure and properties of welded joints produced by pulsating and stationary arcs

    International Nuclear Information System (INIS)

    Comparison studies of the structure and properties of welded joints were carried out for the 245x45 mm pipeline made of the 15Kh1M1F steel and produced by manual welding with pulsating and stationary arcs. Service behaviour of welded joints was evaluated from the metal structure, cold resistance, fracture toughness and heat resistance. The manual welding by pulsating arc is shown to provide formation of 15Kh1M1F steel tube joints with more favourable structure and properties and also with higher cold resistance, deformability and heat resistance. High tempering (710-740 deg C, 3 h) is required for the welded joints produced both by pulsating and stationary arcs

  5. Sub-arc narrow gap welding of the Atucha 2 reactor pressure vessel closure head

    Energy Technology Data Exchange (ETDEWEB)

    Hantsch, H.; Million, K.; Zimmermann, H.; Cerjak, H.; Pellkofer, D.; Schmidt, J.

    1983-01-01

    Narrow-gap technology was used for reasons of design and fabrication when dome of the Atucha 2 reactor pressure vessel was welded to its flange. Preliminary tests has yielded the necessary improvements to the well-established sub-arc practice. New facilities had to be developed for the welding and the accompanying machining work (finishing in the narrow gap). Special measures were adopted for monitoring the welding process and for recording the welding parameters. The new method was tried out on several large test coupons before the welding of the final product was started. No difficulties were encountered during the work.

  6. Sub-arc narrow gap welding of the Atucha 2 reactor pressure vessel closure head

    International Nuclear Information System (INIS)

    Narrow-gap technology was used for reasons of design and fabrication when dome of the Atucha 2 reactor pressure vessel was welded to its flange. Preliminary tests has yielded the necessary improvements to the well-established sub-arc practice. New facilities had to be developed for the welding and the accompanying machining work (finishing in the narrow gap). Special measures were adopted for monitoring the welding process and for recording the welding parameters. The new method was tried out on several large test coupons before the welding of the final product was started. No difficulties were encountered during the work. (orig.)

  7. Improving Processes of Mechanized Pulsed Arc Welding of Low-Frequency Range Variation of Mode Parameters

    Science.gov (United States)

    Saraev, Yu N.; Solodskiy, S. A.; Ulyanova, O. V.

    2016-04-01

    A new technology of low-frequency modulation of the arc current in MAG and MIG welding is presented. The technology provides control of thermal and crystallization processes, stabilizes the time of formation and crystallization of the weld pool. Conducting theoretical studies allowed formulating the basic criteria for obtaining strong permanent joints for high-duty structures, providing conditions for more equilibrium structure of the deposited metal and the smaller width of the HAZ. The stabilization of time of the formation and crystallization of the weld pool improves the formation of the weld and increases productivity in welding thin sheet metal.

  8. Cold Cracking of Flux Cored Arc Welded Armour Grade High Strength Steel Weldments

    Institute of Scientific and Technical Information of China (English)

    G.Magudeeswaran; V.Balasubramanian; G.Madhusudhan Reddy

    2009-01-01

    In this investigation, an attempt has been made to study the influence of welding consumables on the factors that influence cold cracking of armour grade quenched and tempered (Q&T) steel welds. Flux cored arc welding (FCAW) process were used making welds using austenitic stainless steel (ASS) and low hydrogen ferritic steel (LHF) consumables. The diffusible hydrogen levels in the weld metal of the ASS and LHF consumables were determined by mercury method. Residual stresses were evaluated using X-ray stress analyzer and implant test was carried out to study the cold cracking of the welds. Results indicate that ASS welds offer a greater resistance to cold cracking of armour grade Q&T steel welds.

  9. The effect of impurity gasses on variable polarity plasma arc welded 2219 aluminum

    Science.gov (United States)

    Mcclure, John C.; Torres, Martin R.; Gurevitch, Alan C.; Newman, Robert A.

    1989-01-01

    Variable polarity plasma arc (VPPA) welding has been used with considerable success by NASA for the welds on the Space Shuttle External Tank as well as by others concerned with high quality welded structures. The effects of gaseous contaminants on the appearance of VPPA welds on 2219 aluminum are examined so that a welder can recognize that such contamination is present and take corrective measures. There are many possible sources of such contamination including, contaminated gas bottles, leaks in the gas plumbing, inadequate shield gas flow, condensed moisture in the gas lines or torch body, or excessive contaminants on the workpiece. The gasses chosen for study in the program were nitrogen, oxygen, methane, and hydrogen. Welds were made in a carefully controlled environment and comparisons were made between welds with various levels of these contaminants and welds made with research purity (99.9999 percent) gasses. Photographs of the weld front and backside as well as polished and etched cross sections are presented.

  10. Influence of flux-cored wire composition on arc combustion process stability in wet underwater welding

    OpenAIRE

    Kakhovskyi, Mykola Yu.; Maksimov, Serhii Yu.

    2015-01-01

    The components-stabilizers, which increase the stability of the arc combustion process have been investigated. The aim of research was to introduce the components-stabilizers in the welding wire to determine the component which provides the most optimal stability process of the arc combustion. The welding wire characteristics were experimentally studied. They are the quantity of short circuits, the deviations of current and the voltage and nature of the electrode metal transfer. The most stab...

  11. A novel wavelet method for electric signals analysis in underwater arc welding

    Institute of Scientific and Technical Information of China (English)

    Zhang Weimin; Wang Guorong; Shi Yonghua; Zhong Biliang

    2009-01-01

    Electric signals are acquired and analyzed in order to monitor the underwater arc welding process. Voltage break point and magnitude are extracted by detecting arc voltage singularity through the modulus maximum wavelet (MMW) method. A novel threshold algorithm, which compromises the hard-threshold wavelet (HTW) and soft-threshold wavelet (STW) methods, is investigated to eliminate welding current noise. Finally, advantages over traditional wavelet methods are verified by both simulation and experimental results.

  12. Method of plasma-arc welding and properties of welded joints of the 12Kh18N10T steel tubes

    International Nuclear Information System (INIS)

    The aim of the work was to improve the plasma-arc welding of 12Kh18N10T steel pipes for service at temperatures up to 350 deg C under cyclic loading. The quality of welds was checked by metallographic means and by tests for tensile and impact strengths, small-cycle fatigue and hardness. A method was developed for plasma-arc welding of pivoting pipe joints with wall thicknesses of 6-10 mm in a single pass without bevelling of edges and without additive. Welds made by the above procedure possess a higher resistance to failure as compared to manual electric-arc welds

  13. Operation reliability of plasma arc-welded joints for NPP pipings

    International Nuclear Information System (INIS)

    A technology has been developed of plasma-arc welding joints of pipe of steel 12Kh18N10T to replace the factory welding technology using the electrodes EA-400/10 t. It is established that the decisive influence of the formation and microcontinuity of the welded joint is produced by satisfying the optimum values of current and welding rate. Deviation from these values results in nonpenetrations and burnings. A study has been made of the welded joint strength properties at temperatures of 20, 200, 350 deg C and low-cycle fatigue at 350 deg C. The joints made by plasma-arc welding are shown to have higher cyclic strength and resistance to brittle fracture than those made by the former technology

  14. One-knob self-optimizing fuzzy control of CO2 arc welding process

    Institute of Scientific and Technical Information of China (English)

    俞建荣; 蒋力培

    2002-01-01

    A new one-knob self-optimizing fuzzy control system of CO2 arc welding is established based on the synthetic performance evaluation of droplet transfer process. It includes two kinds of self-optimizing fuzzy controllers: the arc voltage controller and the current waveform controller. The fuzzy control principle and the key points of the control patterns are presented. Through on-line detecting, computing of characteristic parameters and one-knob self-optimizing adjusting, the characteristic parameters and welding variables can be adjusted to suitable ranges under the control of the arc voltage controller. Meanwhile the current waveform controller is active in the rear-time stage of the short-circuiting and the instant of re-triggering arc. The experiment results show that the control and its algorithm can improve the synthetic performance of arc welding process apparently.

  15. Numerical study of arc plasmas and weld pools for GTAW with applied axial magnetic fields

    International Nuclear Information System (INIS)

    A 3D numerical model containing the welding arc and the weld pool for gas tungsten arc welding (GTAW) with applied axial magnetic fields is established. The model is validated by comparing the calculated arc temperature with the measured ones. The influence of the magnetic field on the welding process is studied by changing the magnetic inductions, from 0 T to 0.06 T. For welding arcs, a radial spread is discovered, and a reverse flow appears over the anode. The distribution of temperature, heat flux, current density and pressure on the anode surface becomes double-peaked, while the voltage distributes in a double-valley type. For weld pools, the fluid flow cycle brings about a wide and shallow pool. In the circumferential direction, the fluid in the centre areas rotates in an opposite direction to that in the outer regions; in the axial direction, the fluid flows upwards at the centre while downwards in the edge area of the weld pool. All the driving forces including the surface tension, the shear stress from the arc plasma, the electromagnetic force and the buoyancy force that influence the fluid flow are analysed to explain these phenomena. The mechanism of how the applied axial magnetic field regulates the GTAW process is thus clarified. (paper)

  16. 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)

  17. Study on full automatic arc welding machine for spherical tank

    Institute of Scientific and Technical Information of China (English)

    蒋力培; 张甲英; 俞建荣

    2002-01-01

    A full automatic welding machine for spherical tanks' all position multi-layer welds has been developed. This machine is mainly composed of a two-dimension seam tracking system based on microcomputer's memory and a welding tractor as well as rail. The main features of the machine are: while welding the first layer of a seam, its microcomputer system can analyze and store the tracing information from a two-dimension sensor, and control the welding head device to realize two-dimension real time tracing; while welding the second layer up to the top layer of the seam, it can realize two-dimension tracing based on the memorial data, automatically determine the layer number and continually sway the welding head. The welding test shows that the machine has good tracing and welding behavior, and is suitable for spherical tank's all position multi-layer welds.

  18. 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...

  19. Numerical modelling of steel arc welding; Modelisation numerique du soudage a l'arc des aciers

    Energy Technology Data Exchange (ETDEWEB)

    Hamide, M

    2008-07-15

    Welding is a highly used assembly technique. Welding simulation software would give access to residual stresses and information about the weld's microstructure, in order to evaluate the mechanical resistance of a weld. It would also permit to evaluate the process feasibility when complex geometrical components are to be made, and to optimize the welding sequences in order to minimize defects. This work deals with the numerical modelling of arc welding process of steels. After describing the industrial context and the state of art, the models implemented in TransWeld (software developed at CEMEF) are presented. The set of macroscopic equations is followed by a discussion on their numerical implementation. Then, the theory of re-meshing and our adaptive anisotropic re-meshing strategy are explained. Two welding metal addition techniques are investigated and are compared in terms of the joint size and transient temperature and stresses. The accuracy of the finite element model is evaluated based on experimental results and the results of the analytical solution. Comparative analysis between experimental and numerical results allows the assessment of the ability of the numerical code to predict the thermomechanical and metallurgical response of the welded structure. The models limitations and the phenomena identified during this study are finally discussed and permit to define interesting orientations for future developments. (author)

  20. Double-Sided Single-Pass Submerged Arc Welding for 2205 Duplex Stainless Steel

    Science.gov (United States)

    Luo, Jian; Yuan, Yi; Wang, Xiaoming; Yao, Zongxiang

    2013-09-01

    The duplex stainless steel (DSS), which combines the characteristics of ferritic steel and austenitic steel, is used widely. The submerged arc welding (SAW) method is usually applied to join thick plates of DSS. However, an effective welding procedure is needed in order to obtain ideal DSS welds with an appropriate proportion of ferrite (δ) and austenite (γ) in the weld zone, particularly in the melted zone and heat-affected zone. This study evaluated the effectiveness of a high efficiency double-sided single-pass (DSSP) SAW joining method for thick DSS plates. The effectiveness of the converse welding procedure, characterizations of weld zone, and mechanical properties of welded joint are analyzed. The results show an increasing appearance and continuous distribution feature of the σ phase in the fusion zone of the leading welded seam. The converse welding procedure promotes the σ phase to precipitate in the fusion zone of leading welded side. The microhardness appears to significantly increase in the center of leading welded side. Ductile fracture mode is observed in the weld zone. A mixture fracture feature appears with a shear lip and tears in the fusion zone near the fusion line. The ductility, plasticity, and microhardness of the joints have a significant relationship with σ phase and heat treatment effect influenced by the converse welding step. An available heat input controlling technology of the DSSP formation method is discussed for SAW of thick DSS plates.

  1. 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

  2. Narrow gap mechanised arc welding in nuclear components manufactured by AREVA NP

    International Nuclear Information System (INIS)

    Nuclear components require welds of irreproachable and reproducible quality. Moreover, for a given welding process, productivity requirements lead to reduce the volume of deposited metal and thus to use narrow gap design. In the shop, narrow gap Submerged Arc Welding process (SAW) is currently used on rotating parts in flat position for thicknesses up to 300 mm. Welding is performed with one or two wires in two passes per layer. In Gas Tungsten Arc Welding process (GTAW), multiple applications can be found because this process presents the advantage of allowing welding in all positions. Welding is performed in one or two passes per layer. The process is used in factory and on the nuclear sites for assembling new components but also for replacing components and for repairs. Presently, an increase of productivity of the process is sought through the use of hot wire and/or two wires. Concerning Gas Metal Arc Welding process (GMAW), its use is growing for nuclear components, including narrow gap applications. This process, limited in its applications in the past on account of the defects it generated, draws benefit from the progress of the welding generators. Then it is possible to use this efficient process for high security components such as those of nuclear systems. It is to be noted that the process is applicable in the various welding positions as it is the case for GTAW, while being more efficient than the latter. This paper presents the state of the art in the use of narrow gap mechanised arc welding processes by AREVA NP units. (author)

  3. Microstructure and pitting corrosion of shielded metal arc welded high nitrogen stainless steel

    Directory of Open Access Journals (Sweden)

    Raffi Mohammed

    2015-09-01

    Full Text Available The present work is aimed at studying the microstructure and pitting corrosion behaviour of shielded metal arc welded high nitrogen steel made of Cromang-N electrode. Basis for selecting this electrode is to increase the solubility of nitrogen in weld metal due to high chromium and manganese content. Microscopic studies were carried out using optical microscopy (OM and field emission scanning electron microscopy (FESEM. Energy back scattered diffraction (EBSD method was used to determine the phase analysis, grain size and orientation image mapping. Potentio-dynamic polarization testing was carried out to study the pitting corrosion resistance in aerated 3.5% NaCl environment using a GillAC electrochemical system. The investigation results showed that the selected Cr–Mn–N type electrode resulted in a maximum reduction in delta-ferrite and improvement in pitting corrosion resistance of the weld zone was attributed to the coarse austenite grains owing to the reduction in active sites of the austenite/delta ferrite interface and the decrease in galvanic interaction between austenite and delta-ferrite.

  4. 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.

  5. Hazard of ultraviolet radiation emitted in gas tungsten arc welding of aluminum alloys.

    Science.gov (United States)

    Nakashima, Hitoshi; Utsunomiya, Akihiro; Fujii, Nobuyuki; Okuno, Tsutomu

    2016-03-28

    Ultraviolet radiation (UVR) emitted during arc welding frequently causes keratoconjunctivitis and erythema. The extent of the hazard of UVR varies depending on the welding method and conditions. Therefore, it is important to identify the levels of UVR that are present under various conditions. In this study, we experimentally evaluated the hazard of UVR emitted in gas tungsten arc welding (GTAW) of aluminum alloys. The degree of hazard of UVR is measured by the effective irradiance defined in the American Conference of Governmental Industrial Hygienists guidelines. The effective irradiances measured in this study are in the range 0.10-0.91 mW/cm(2) at a distance of 500 mm from the welding arc. The maximum allowable exposure times corresponding to these levels are only 3.3-33 s/day. This demonstrates that unprotected exposure to UVR emitted by GTAW of aluminum alloys is quite hazardous in practice. In addition, we found the following properties of the hazard of UVR. (1) It is more hazardous at higher welding currents than at lower welding currents. (2) It is more hazardous when magnesium is included in the welding materials than when it is not. (3) The hazard depends on the direction of emission from the arc. PMID:26632121

  6. Rotating arc horizontal narrow gap welding of high strength quenched and tempered steel

    Institute of Scientific and Technical Information of China (English)

    Guo Ning; Yang Chunli; Han Yanfei; Jia Chuanbao; Du Yongpeng; Zhang Linlin

    2010-01-01

    Rotating arc horizontal narrow gap welding of quenched & tempered ( Q&T) steel was innovatively performed for solving the bottleneck that the molten pool sagged due to the gravity. The shapely multilayer single pass horizontal joint could be obtained by using the rotating arc welding process. The cold crack was not observed in the joint without controlling the heat input and selecting the consumables intentionally. Mkrostructure of the joint could be divided into three zones:base metal zone ( BMZ) , heat-affected zone (HAZ) and weld zone ( WZ). Because of the characteristic of the rotating arc horizontal welding process, the defects in the joints were slag inclusion formed at the inUrlayer of lower side wall. The tensile strength and hardness of HAZ and WZ were larger than those of BMZ. The impact toughness in WZ, HAZ and BM at 0℃ is equal to 115, 212 and 236 J, respectively.

  7. 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

  8. An adaptive control system for off-line programming in robotic gas metal arc welding.

    OpenAIRE

    Carvalho, G. C.

    1997-01-01

    The aim of this work was to develop an integration concept for using off-line programming in robotic gas metal arc welding of thin sheet steel. Off line -welding parameter optimization and on-line monitoring and adaptive control of process stability and torch-to-workpiece relative distance were used to ensure weld consistency. The concept developed included four main aspects: a) the use of a CAD system to design the workpiece; b) the use of a welding off-line programming ...

  9. Microstructure and mechanical properties of aluminum 5083 weldments by gas tungsten arc and gas metal arc welding

    International Nuclear Information System (INIS)

    Highlights: ► Welding zones by GTAW and GMAW are softer than the parent material Al5083. ► GTAW for Al5083 are mechanically more reliable than that welded by GMAW. ► GTAW welds fail by shear, but GMAW welds show mixed shear and normal failure. - Abstract: The mechanical properties and microstructural features of aluminum 5083 (Al5083) weldments processed by gas tungsten arc welding (GTAW) and gas metal arc welding (GMAW) are investigated. Weldments processed by both methods are mechanically softer than the parent material Al5083, and could be potential sites for plastic localization. It is revealed that Al5083 weldments processed by GTAW are mechanical more reliable than those by GMAW. The former bears higher strength, more ductility, and no apparent microstructure defects. Perceivable porosity in weldments by GMAW is found, which could account for the distinct mechanical properties between weldments processed by GTAW and GMAW. It is suggested that caution should be exercised when using GMAW for Al5083 in the high-speed-train industry where such light weight metal is broadly used.

  10. Interfacial microstructure and properties of copper clad steel produced using friction stir welding versus gas metal arc welding

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Z.; Chen, Y. [Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo (Canada); Haghshenas, M., E-mail: mhaghshe@uwaterloo.ca [Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo (Canada); Nguyen, T. [Mechanical Systems Engineering, Conestoga College, Kitchener (Canada); Galloway, J. [Welding Engineering Technology, Conestoga College, Kitchener (Canada); Gerlich, A.P. [Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo (Canada)

    2015-06-15

    A preliminary study compares the feasibility and microstructures of pure copper claddings produced on a pressure vessel A516 Gr. 70 steel plate, using friction stir welding versus gas metal arc welding. A combination of optical and scanning electron microscopy is used to characterize the grain structures in both the copper cladding and heat affected zone in the steel near the fusion line. The friction stir welding technique produces copper cladding with a grain size of around 25 μm, and no evidence of liquid copper penetration into the steel. The gas metal arc welding of copper cladding exhibits grain sizes over 1 mm, and with surface microcracks as well as penetration of liquid copper up to 50 μm into the steel substrate. Transmission electron microscopy reveals that metallurgical bonding is produced in both processes. Increased diffusion of Mn and Si into the copper cladding occurs when using gas metal arc welding, although some nano-pores were detected in the FSW joint interface. - Highlights: • Cladding of steel with pure copper is possible using either FSW or GMAW. • The FSW yielded a finer grain structure in the copper, with no evidence of cracking. • The FSW joint contains some evidence of nano-pores at the interface of the steel/copper. • Copper cladding by GMAW contained surface cracks attributed to high thermal stresses. • The steel adjacent to the fusion line maintained a hardness value below 248 HV.

  11. Interfacial microstructure and properties of copper clad steel produced using friction stir welding versus gas metal arc welding

    International Nuclear Information System (INIS)

    A preliminary study compares the feasibility and microstructures of pure copper claddings produced on a pressure vessel A516 Gr. 70 steel plate, using friction stir welding versus gas metal arc welding. A combination of optical and scanning electron microscopy is used to characterize the grain structures in both the copper cladding and heat affected zone in the steel near the fusion line. The friction stir welding technique produces copper cladding with a grain size of around 25 μm, and no evidence of liquid copper penetration into the steel. The gas metal arc welding of copper cladding exhibits grain sizes over 1 mm, and with surface microcracks as well as penetration of liquid copper up to 50 μm into the steel substrate. Transmission electron microscopy reveals that metallurgical bonding is produced in both processes. Increased diffusion of Mn and Si into the copper cladding occurs when using gas metal arc welding, although some nano-pores were detected in the FSW joint interface. - Highlights: • Cladding of steel with pure copper is possible using either FSW or GMAW. • The FSW yielded a finer grain structure in the copper, with no evidence of cracking. • The FSW joint contains some evidence of nano-pores at the interface of the steel/copper. • Copper cladding by GMAW contained surface cracks attributed to high thermal stresses. • The steel adjacent to the fusion line maintained a hardness value below 248 HV

  12. Improvement of weld material for automatic or semi-automatic welding of creep resistant steel casting compared with manual arc welding. Project D37

    International Nuclear Information System (INIS)

    In cooperation with the projects CH7, D16 and D36 (leadership), project D37 deals with the evaluation of the low cycle fatigue (LCF) behaviour of improved welded joints of heat resistant 1 CrMoV-cast steel (GS-17 CrMoV 5 11). The aim of the whole project is the qualification of automatic welding techniques as shielded metal arc (SMA) and submerged arc (SA) compared to manual arc (MA) and the determination of the optimum postweld heat treatment in respect to sufficient properties. LCF-tests, carried out at 550 C and at total strain ranges of 0, 3 to 2% show that the different welding techniques (MA, SMA, SA) and postweld heat treatments (tempering, hardening, diffusion annealing) result in a common scatterband. All investigated variants seem to have sufficient LCF-properties for practical purpose. (orig.)

  13. Analisa Ketangguhan dan Struktur Mikro pada Daerah Las dan HAZ Hasil Pengelasan Sumerged Arc Welding pada Baja SM 490

    OpenAIRE

    Yusa Asra Yuli Wardana; Anang Setiawan

    2006-01-01

    Submerged Arc Welding (SAW) is one of method for welding process which used for the extensions of heavy construction, for example bridge construction. Broadness usage of SAW caused by welding process can be done automatically and have high reliability. Microstructure and toughness properties of weld metal were influenced by many factors such as chemical composition, heat input, filler, fluks, etc. This research aim to study influence of heat input. Welding Process was carried out using SAW wi...

  14. Gas metal arc welding of butt joint with varying gap width based on neural networks

    DEFF Research Database (Denmark)

    Christensen, Kim Hardam; Sørensen, Torben

    2005-01-01

    This paper describes the application of the neural network technology for gas metal arc welding (GMAW) control. A system has been developed for modeling and online adjustment of welding parameters, appropriate to guarantee a certain degree of quality in the field of butt joint welding with full...... penetration, when the gap width is varying during the welding process. The process modeling to facilitate the mapping from joint geometry and reference weld quality to significant welding parameters, has been based on a multi-layer feed-forward network. The Levenberg-Marquardt algorithm for non-linear least...... squares has been used with the back-propagation algorithm for training the network, while a Bayesian regularization technique has been successfully applied for minimizing the risk of inexpedient over-training. Finally, a predictive closed-loop control strategy based on a so-called single-neuron self...

  15. Occupational asthma due to manual metal-arc welding of special stainless steels.

    Science.gov (United States)

    Hannu, T; Piipari, R; Kasurinen, H; Keskinen, H; Tuppurainen, M; Tuomi, T

    2005-10-01

    Occupational asthma (OA) can be induced by fumes of manual metal-arc welding on stainless steel. In recent years, the use of special stainless steels (SSS) with high chromium content has increased. This study presents two cases of OA caused by manual metal-arc welding on SSS. In both cases, the diagnosis of OA was based on respiratory symptoms, occupational exposure and positive findings in the specific challenge tests. In the first case, a 46-yr-old welder had experienced severe dyspnoea while welding SSS (SMO steel), but not in other situations. Challenge tests with both mild steel and stainless steel using a common electrode were negative. Welding SSS with a special electrode caused a delayed 37% drop in forced expiratory volume in one second (FEV1). In the second case, a 34-yr-old male had started to experience dyspnoea during the past few years, while welding especially SSS (Duplex steel). The workplace peak expiratory flow monitoring was suggestive of OA. Challenge tests with both mild steel and stainless steel using a common electrode did not cause bronchial obstruction. Welding SSS with a special electrode caused a delayed 31% drop in FEV1. In conclusion, exposure to manual metal-arc welding fumes of special stainless steel should be considered as a new cause of occupational asthma. PMID:16204606

  16. Study of welding velocity and pulse frequency on microstructure and mechanical properties of pulsed gas metal arc welded high strength low alloy steel

    International Nuclear Information System (INIS)

    Highlights: • Effect of welding velocity and pulse frequency in GMAW of HSLA steel. • Dependency of weldment microstructure on the welding velocity and pulse. • Reduction of hardness in the weld zone and HAZ with increasing of heat input. • The higher strength due to the higher amount of martensite. • Deterioration of impact properties with formation of grain boundary ferrite. - Abstract: The microstructure analysis and mechanical properties evaluation of pulsed gas metal arc and conventional gas metal arc welded high strength low alloy (HSLA) steel joints were investigated. Welding was carried out at welding velocity of 10 and 15 cm/min and pulse frequency of 50 and 100 Hz. The joints were subjected to optical microscope, scanning electron microscope, hardness, tensile test and Charpy impact toughness testing. Results showed that at high welding velocity the microstructure of the weld metal consisted mainly of acicular ferrite and lath martensite. At low welding velocity, small amounts of allotriomorphic and Widmanstatten ferrite were also observed. Results also showed that good mechanical properties can be obtained through the pulsed gas metal arc welding with welding velocity of 15 cm/min and pulse frequency of 50 Hz. Furthermore, with decreasing of welding velocity and increasing of the pulse frequency, impact energy decreased. This can be attributed to the formation of grain boundary ferrite and higher volume fraction of inclusion in weld metal. Results of fractography showed ductile fracture as a result of the equiaxed microvoids

  17. Influence of copper content of steel welding wires on the fume formation rate in gas metal arc welding

    International Nuclear Information System (INIS)

    Increase in the fume formation rate (FFR) during welding with copper-coated wires has been attributed to the copper coating. However, instability during the welding process can have an influence on the FFR. To overcome this problem, the University of Wollongong has developed an auto-control system that can minimise the influence of the instability and thus allow more accurate determination of the FFR in the 'drop-spray' mode of transfer. Investigation of the FFR associated with gas metal arc welding using copper-coated wires in the drop-spray mode confirmed that an increase in the FFR of copper-coated welding wires does occur, but the increase was not found to be directly proportional to the increase in copper content of the wire.

  18. Achieving High Strength Joint of Pure Copper Via Laser-Cold Metal Transfer Arc Hybrid Welding

    Science.gov (United States)

    Chen, Yulong; Chen, Cong; Gao, Ming; Zeng, Xiaoyan

    2016-06-01

    Fiber laser-cold metal transfer arc hybrid welding of pure copper was studied. Weld porosity was tested by X-ray nondestructive testing. Microstructure and fracture features were observed by scanning electron microscopy. Mechanical properties were evaluated by cross weld tensile test. Full penetrated and continuous welds were obtained by hybrid welding once the laser power reached 2 kW, while they could not be obtained by laser welding alone, even though the laser power reached 5 kW. The ultimate tensile strength (UTS), the yield strength (YS), and the elongation of the best hybrid weld material were up to 227, 201 MPa, and 21.5 pct, respectively. The joint efficiencies in UTS and YS of hybrid weld were up to 84 and 80 pct of the BM, respectively. The fracture location changes from the fusion zone to the heat-affected zone with the increase of laser power. Besides, the mechanisms of process stability and porosity suppression were clarified by laser-arc interaction and pool behavior. The strengthening mechanism was discussed by microstructure characteristics.

  19. Achieving High Strength Joint of Pure Copper Via Laser-Cold Metal Transfer Arc Hybrid Welding

    Science.gov (United States)

    Chen, Yulong; Chen, Cong; Gao, Ming; Zeng, Xiaoyan

    2016-04-01

    Fiber laser-cold metal transfer arc hybrid welding of pure copper was studied. Weld porosity was tested by X-ray nondestructive testing. Microstructure and fracture features were observed by scanning electron microscopy. Mechanical properties were evaluated by cross weld tensile test. Full penetrated and continuous welds were obtained by hybrid welding once the laser power reached 2 kW, while they could not be obtained by laser welding alone, even though the laser power reached 5 kW. The ultimate tensile strength (UTS), the yield strength (YS), and the elongation of the best hybrid weld material were up to 227, 201 MPa, and 21.5 pct, respectively. The joint efficiencies in UTS and YS of hybrid weld were up to 84 and 80 pct of the BM, respectively. The fracture location changes from the fusion zone to the heat-affected zone with the increase of laser power. Besides, the mechanisms of process stability and porosity suppression were clarified by laser-arc interaction and pool behavior. The strengthening mechanism was discussed by microstructure characteristics.

  20. A numerical simulation method of arc welding; Une methode de simulation numerique du soudage a l arc

    Energy Technology Data Exchange (ETDEWEB)

    Chau, T.T. [AREVA TA (Technicatome), Centre Jean-Louis Andrieu, BP34000, 13791 Aix-en-Provence Commission Simulation Numerique du Soudage (AFM / SNS), Paris La Defense (France)

    2006-07-01

    Nowadays, in metal industries, are more and more used weak thicknesses steel sheets to reduce the mass and optimize the resistance of the structures to make with the electric arc welding which remains always the most used and most economical technique. Deformations and residual stresses of most or less important levels are introduced too in the assembling thus welded. The methodology presented here can help the designer-manufacturer engineer to estimate the levels of these effects and to optimize the design and manufacture parameters for reaching the wanted performances in his plans with few computer time on 3D numerical models of great sizes. (O.M.)

  1. Microstructure and corrosion behaviour of gas tungsten arc welds of maraging steel

    Directory of Open Access Journals (Sweden)

    G. Madhusudhan Reddy

    2015-03-01

    Full Text Available Superior properties of maraging steels make them suitable for the fabrication of components used for military applications like missile covering, rocket motor casing and ship hulls. Welding is the main process for fabrication of these components, while the maraging steels can be fusion welded using gas tungsten arc welding (GTAW process. All these fabricated components require longer storage life and a major problem in welds is susceptible to stress corrosion cracking (SCC. The present study is aimed at studying the SCC behaviour of MDN 250 (18% Ni steel and its welds with respect to microstructural changes. In the present study, 5.2 mm thick sheets made of MDN 250 steel in the solution annealed condition was welded using GTAW process. Post-weld heat treatments of direct ageing (480 °C for 3 h, solutionizing (815 °C for 1 h followed by ageing and homogenizing (1150 °C for 1 h followed by ageing were carried out. A mixture of martensite and austenite was observed in the microstructure of the fusion zone of solutionized and direct aged welds and only martensite in as-welded condition. Homogenization and ageing treatment have eliminated reverted austenite and elemental segregation. Homogenized welds also exhibited a marginal improvement in the corrosion resistance compared to those in the as-welded, solutionized and aged condition. Constant load SCC test data clearly revealed that the failure time of homogenized weld is much longer compared to other post weld treatments, and the homogenization treatment is recommended to improve the SCC life of GTA welds of MDN 250 Maraging steel.

  2. Development of Process Maps in Two-Wire Tandem Submerged Arc Welding Process of HSLA Steel

    Science.gov (United States)

    Kiran, D. V.; Alam, S. A.; De, A.

    2013-04-01

    Appropriate selection of welding conditions to guarantee requisite weld joint mechanical properties is ever difficult because of their complex interactions. An approach is presented here to identify suitable welding conditions in typical two-wire tandem submerged arc welding (SAW-T) that involves many welding variables. First, an objective function is defined, which depicts the squared error between the mechanical properties of weld joint and of base material. A set of artificial neural network (ANN)-based models are developed next to estimate the weld joint properties as function of welding conditions using experimentally measured results. The neural network model-based predictions are used next to create a set of process map contours that depict the minimum achievable values of the objective function and the corresponding welding conditions. In typical SAW-T of HSLA steel, welding speed from 9.0 to 11.5 mm/s, leading wire current from 530 to 580 A, and trailing wire negative current from 680 to 910 A are found to be the most optimal.

  3. Improvements of welding characteristics of aluminum alloys with YAG laser and TIG arc hybrid system

    Science.gov (United States)

    Fujinaga, Shigeki; Ohashi, Ryoji; Katayama, Seiji; Matsunawa, Akira

    2003-03-01

    In high power YAG laser welding of steels, a rectangularly modulated beam with high peak power is usually used to get deep penetration. On the other hand, many spatters and solidification cracks are generated when some aluminum alloys are welded with a rectangularly modulated beam because of its high heat conductivity, high reflectivity, low surface tension, large contraction, wide solidification temperature range, etc. Therefore, a properly modulated beam or a continuous beam is usually used in aluminum alloy welding, although the penetration depth is shallow. In this research, sinusoidal wave or rectangularly modulated wave of YAG laser combined with TIG arc was tried to improve the weldability of A6061 aluminum alloy. As a result, when TIG arc was superimposed behind the YAG laser beam, deeply penetrated weld beads with good surface appearances were produced without spatter losses and cracks.

  4. Using active contour models for feature extraction in camera-based seam tracking of arc welding

    DEFF Research Database (Denmark)

    Liu, Jinchao; Fan, Zhun; Olsen, Søren;

    2009-01-01

    the processes requires the extraction of characteristic parameters of the welding groove close to the molten pool, i.e. in an environment dominated by the very intense light emission from the welding arc. The typical industrial solution today is a laser-scanner containing a camera as well as a laser......In the recent decades much research has been performed in order to allow better control of arc welding processes, but the success has been limited, and the vast majority of the industrial structural welding work is therefore still being made manually. Closed-loop and nearly-closed-loop control of...... source illuminating the groove by a light curtain and thus allowing details of the groove geometry to be extracted by triangulation. This solution is relatively expensive and must act several centimetres ahead of the molten pool. In addition laser-scanners often show problems when dealing with shiny...

  5. Hybrid Visual Servoing Control for Robotic Arc Welding Based on Structured Light Vision

    Institute of Scientific and Technical Information of China (English)

    XUDe; WANGLin-Kun; TUZhi-Guo; TANMin

    2005-01-01

    A novel hybrid visual servoing control method based on structured light vision is proposed for robotic arc welding with a general six degrees of freedom robot. It consists of a position control inner-loop in Cartesian space and two outer-loops. One is position-based visual control inCartesian space for moving in the direction of weld seam, i.e., weld seam tracking, another is imagebased visual control in image space for adjustment to eliminate the errors in the process of tracking.A new Jacobian matrix from image space of the feature point on structured light stripe to Cartesian space is provided for differential movement of the end-effector. The control system model is simplified and its stability is discussed. An experiment of arc welding protected by gas CO2 for verifying is well conducted.

  6. Experience and Applications Up-date: Automation of Arc-Welding Operations Using Robot-Technology

    International Nuclear Information System (INIS)

    In a short introduction, the important criteria for the correct choice of a robot cell, taking into account the given application, are highlighted. Furthermore, important hints are listed in terms of management decisions. The second chapter shows the main features of a welding robot cell in line with the present state of the art and describes some new developments with the aim of extending the arc-welding system to new applications such as flame cutting and beveling. The third chapter as centre piece gives an overall view of a brand new network control with many outstanding features for the users of arc-welding robots. the fourth and last chapter shows a recent realisation of a highly sophisticated F.M.S. system for welding, in random sequence, different large and heavy components. (Author) 1 ref

  7. Examination of the physical processes associated with the keyhole region of variable polarity plasma arc welds in aluminum alloy 2219

    Science.gov (United States)

    Walsh, Daniel W.

    1987-01-01

    The morphology and properties of the Variable Polarity Plasma Arc (VPPA) weld composite zone are intimately related to the physical processes associated with the keyhole. This study examined the effects of oxide, halide, and sulfate additions to the weld plate on the keyhole and the weld pool. Changes in both the arc plasma character and the bead morphology were correlated to the chemical environment of the weld. Pool behavior was observed by adding flow markers to actual VPPA welds. A low temperature analog to the welding process was developed. The results of the study indicate that oxygen, even at low partial pressures, can disrupt the stable keyhole and weld pool. The results also indicate that the Marangoni surface tension driven flows dominate the weld pool over the range of welding currents studied.

  8. Metallurgical characterization of pulsed current gas tungsten arc, friction stir and laser beam welded AZ31B magnesium alloy joints

    International Nuclear Information System (INIS)

    This paper reports the influences of welding processes such as friction stir welding (FSW), laser beam welding (LBW) and pulsed current gas tungsten arc welding (PCGTAW) on mechanical and metallurgical properties of AZ31B magnesium alloy. Optical microscopy, scanning electron microscopy, transmission electron microscopy and X-Ray diffraction technique were used to evaluate the metallurgical characteristics of welded joints. LBW joints exhibited superior tensile properties compared to FSW and PCGTAW joints due to the formation of finer grains in weld region, higher fusion zone hardness, the absence of heat affected zone, presence of uniformly distributed finer precipitates in weld region.

  9. Microstructure and pitting corrosion of shielded metal arc welded high nitrogen stainless steel

    OpenAIRE

    Raffi Mohammed; G. Madhusudhan Reddy; K. Srinivasa Rao

    2015-01-01

    The present work is aimed at studying the microstructure and pitting corrosion behaviour of shielded metal arc welded high nitrogen steel made of Cromang-N electrode. Basis for selecting this electrode is to increase the solubility of nitrogen in weld metal due to high chromium and manganese content. Microscopic studies were carried out using optical microscopy (OM) and field emission scanning electron microscopy (FESEM). Energy back scattered diffraction (EBSD) method was used to determine t...

  10. Effect of different electrode tip angles with tilted torch in stationary gas tungsten arc welding: A 3D simulation

    International Nuclear Information System (INIS)

    In this study, the effect of different tip angles (30°, 60°, 90° and 120°) on the arc and weld pool behavior is analyzed in 2 mm and 5 mm arc lengths with tilted (70°) torch. Arc temperature, velocity, current density, heat flux and gas shear are investigated in the arc region and pool convection and puddle shapes are studied in the weld pool region. The arc temperature at the tungsten electrode is found the maximum with sharp tip and decreases as the tip angle increases. The arc temperature on the anode (workpiece) surface becomes concentrated with increase in tip angle. The arc velocity and gas shear stress are observed large with sharp tip and decreasing as the tip angle increases. Current density on the anode surface does not change with tip angle and observed almost the same in all the tip angles in both 2 mm and 5 mm arc lengths. Heat flux due to conduction and convection is observed more sensitive to the tip angle and decreases as the tip angle increases. The electromagnetic force is slightly observed increasing and the buoyancy force is observed slightly decreasing with increase in tip angle. Analyzing each driving force in the weld pool individually shows that the gas drag and Marangoni forces are much stronger than the electromagnetic and buoyancy forces. The weld pool shape is observed wide and shallow in sharp and narrow and deep in large tip angle. Increasing the arc length does not change the weld pool width; however, the weld pool depth significantly changes with arc length and is observed deep in short arc length. The arc properties and weld pool shapes are observed wide ahead of the electrode tip in the weld direction due to 70° torch angle. Good agreement is observed between the numerical and experimental weld pool shapes

  11. A comparison of residual stresses in multi pass narrow gap laser welds and gas-tungsten arc welds in AISI 316L stainless steel

    International Nuclear Information System (INIS)

    Thick-section austenitic stainless steels have widespread industrial applications, especially in nuclear power plants. The joining methods used in the nuclear industry are primarily based on arc welding processes. However, it has recently been shown that narrow gap laser welding (NGLW) can weld materials with thicknesses that are well beyond the capabilities of single pass autogenous laser welding. The heat input for NGLW is much lower than for arc welding, as are the expected levels of residual stress and distortion. This paper reports on a preliminary investigation of the through-thickness 2D residual stresses distributions, distortions, and plastic strain characteristics, for the NGLW process using material thicknesses up to 20 mm. The results are compared with those obtained with gas-tungsten arc (GTA) welding. While further work is required on thicker test pieces, preliminary results suggest that the longitudinal tensile residual stresses in NGLW joints are 30–40% lower than those for GTA welds. -- Highlights: • The magnitude of the residual stresses is 30–40% lower in the Narrow Gap Laser Welds NGLW in comparison to those for GTA welding. • NGLW technique resulted in a very narrow tensile stress region. • The welding strategy has a significant influence on the induced residual stress for the NGLW technique. • The distortion angle of GTA welds is approximately 3 times higher than for NGLW. • The accumulation of plastic strain due to thermo-mechanical cycling in GTA welding is higher than for NGLW

  12. Automatic all position welding for horizontally fixed tubes by tungsten inert gas arc welding method

    International Nuclear Information System (INIS)

    The welding of fixed tubes is mostly all position welding in restricted places, accordingly much skill is required. The automation of welding is necessary because of the requirement for the reliability of welded joints, the difficulty of securing skilled workers, and welding quality. The development and production of the automatic welders for TIG welding of tubes have been carried out by Mitsubishi Electric Corp., and the application to various purposes was attempted. The TIG welding for the automatic welding of tubes is advantageous, because backside bead can be formed stably, spatter does not arise, welding is stable for every metal, and the mechanism of the automatic welders is simple. But it is not suitable for the welding of zinc-plated tubes, and the rate of deposition is relatively small. It is applied to the welding of boiler tubes, nuclear energy equipments and pipings, chemical equipments and pipings, and aluminum pipings. The specifications and the construction of the TIG tube welders are shown. The preparation of joints and the control of welding conditions are important for guaranteeing the welding results in automatic welding, therefore sufficient consultation with welder makers about these points is required. The welding defects apt to arise are the bad form of backside beads, blowholes, and the insufficient melting of intermediate layers, and the countermeasures to them must be taken. (Kako, I.)

  13. Phase analysis of fume during arc weld brazing of steel sheets with protective coatings

    Directory of Open Access Journals (Sweden)

    J. Matusiak

    2016-04-01

    Full Text Available The article presents the results of research of the phase identification and of the quantitative phase analysis of fume generated during Cold Metal Transfer (CMT, ColdArc and Metal Inert Gas / Metal Active Gas (MIG / MAG weld brazing. Investigations were conducted for hot - dip coated steel sheets with zinc (Zn and zinc-iron (Zn - Fe alloy coatings. Arc shielding gases applied during the research-related tests were Ar + O2, Ar + CO2, Ar + H2 and Ar + CO2 + H2 gas mixtures. The analysis of the results covers the influence of the chemical composition of shielding gas on the chemical composition of welding fume.

  14. Application of pulsed tandem gas metal arc welding for fabrication of high strength steel panels in naval surface vessels

    International Nuclear Information System (INIS)

    Pulsed tandem gas metal arc welding (PT-GMAW) has been identified as a process that is potentially capable of increasing productivity and minimising distortion in the fabrication of surface ship panels. For this study, the PT-GMAW process was used in pulse pulse mode to butt-weld 8 MM HSLA65 steel plate in order to determine its suitability as a replacement for standard gas-metal-arc welding (GMAW) and submerged-arc welding (SAW) in naval shipbuilding. In the pulse-pulse mode, the leading and trailing welding wires alternately transfer metal into a single molten weld pool at deposition rates or travel speeds greater than those used in conventional single-wire arc welding processes. The results showed that the lowest level of distortion occurred in a single-bead butt weld using PT-GMAW. Higher levels of distortion were measured after square-butt welding using double-bead PT-GMAW, with one bead per side; and applying standard GMAW multiple-bead butt welding with a single-V preparation. Although the magnitude of the maximum tensile residual stresses was similar for all welds, the single-bead weld rising PT-GMAW resulted in the largest region of high tensile residual stresses (>500 MPa) in the longitudinal direction. Nevertheless, it showed the lowest distortion and the strength, hardness and impact toughness were similar to those of the double-bead PT-GMAW weldment and the standard GMAW weldment.

  15. 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...

  16. Macroscopic Segregation and Stress Corrosion Cracking in 7xxx Series Aluminum Alloy Arc Welds

    Science.gov (United States)

    Borchers, Tyler E.; McAllister, Donald P.; Zhang, Wei

    2015-05-01

    Arc welds of Al-Zn-Mg alloy with Al-Mg filler wire have shown a preferential macroscopic segregation of Mg and Zn to the weld toes. Islands of large precipitates, which are observed in those solute-enriched weld toes, are identified as T phase (Mg32(Al,Zn)49) using diffraction pattern analysis. The location of T precipitates consistently coincides with the initiation site for stress corrosion cracking. Therefore, it is hypothesized that they induce the crack initiation due to preferential dissolution.

  17. Sensoring Fusion Data from the Optic and Acoustic Emissions of Electric Arcs in the GMAW-S Process for Welding Quality Assessment

    Directory of Open Access Journals (Sweden)

    Eber Huanca Cayo

    2012-05-01

    Full Text Available The present study shows the relationship between welding quality and optical-acoustic emissions from electric arcs, during welding runs, in the GMAW-S process. Bead on plate welding tests was carried out with pre-set parameters chosen from manufacturing standards. During the welding runs interferences were induced on the welding path using paint, grease or gas faults. In each welding run arc voltage, welding current, infrared and acoustic emission values were acquired and parameters such as arc power, acoustic peaks rate and infrared radiation rate computed. Data fusion algorithms were developed by assessing known welding quality parameters from arc emissions. These algorithms have showed better responses when they are based on more than just one sensor. Finally, it was concluded that there is a close relation between arc emissions and quality in welding and it can be measured from arc emissions sensing and data fusion algorithms.

  18. High-strength, high-fracture toughness submerged-arc weld for arctic line pipe

    International Nuclear Information System (INIS)

    In this study, the development of a high-strength, high-fracture toughness double submerged-arc weld for X-70 arctic grade line pipe is documented. The weld was made with a two-wire DC/AC tandem setup at a speed of 27.5 mm/s (65 in./min.). A fused, semi-neutral, fine grained (32 x 200) flux was used. The resulting weld metal microstructure was at least 95% acicular ferrite. The weld had excellent fracture toughness with not less than 60 joules at -600C and 50% FATT at -500C. The formation of acicular ferrite was interpreted as the result of suppression of proeutectoid ferrite owing to the high molybdenum content of the wire and the presence of TiO2 inclusions. The properties were consistently achieved during the manufacture of spirally welded pipes 1067 mm 0.D x 14 mm W.T

  19. Application of RVM for prediction of bead shape in underwater rotating arc welding

    Institute of Scientific and Technical Information of China (English)

    Du Jianhui; Shi Yonghua; Wang Guorong; Huang Guoxing

    2010-01-01

    Bead shape in underwater rotating arc welding was affected by several welding parameters.RVM(relevance vector machine)was used to build a model to predict weld bead shape.The training data set of RVM consists of the welding parameters which are rotational frequency,rotational radius,height of torch and welding current and the features of the bead shape.The maximum error and mean error for prediction of width are 0.10 mm and 0.09 mm,respectively,and the maximum error and mean error for prediction of penetration are 0.31 nun and 0.12 mm,respectively,which are showed that the prediction model can achieve higher prediction precision at reasonably small size of training data set.

  20. Microstructure and Mechanical Properties of Hybrid Welded Joints with Laser and CO2-Shielded Arc

    Science.gov (United States)

    Wahba, M.; Mizutani, M.; Katayama, S.

    2016-06-01

    With the objective of reducing the operating costs, argon-rich shielding gas was replaced by 100% CO2 gas in hybrid laser-arc welding of shipbuilding steel. The welding parameters were optimized to obtain buried-arc transfer in order to mitigate spatter formation. Sound butt joints could be successfully produced for plates of 14 and 17 mm thickness in one welding pass. Subsequently, the welded joints were subjected to different tests to evaluate the influence of CO2 shielding gas on the mechanical properties of the welded joints. All tensile-tested specimens failed in the base material, indicating the higher strength of the welded joints. The impact toughness of the welded joints, measured at -20 °C, reached approximately 76% of that of the base material, which was well above the limit set by the relevant standard. The microstructure of the fusion zone consisted of grain boundary ferrite and acicular ferrite uniformly over the plate thickness except for the joint root where the microstructure was chiefly ferrite with an aligned second phase. This resulted in higher hardness in the root region compared with the top and middle parts of the fusion zone.

  1. Microstructure and corrosion behavior of multipass gas tungsten arc welded 304L stainless steel

    International Nuclear Information System (INIS)

    Highlights: • Multipass gas tungsten arc welding of 304L stainless steel was successfully done. • All welds were austenitic with the presence of a small amount of δ-ferrite. • The morphology of δ-ferrite showed the lathy and skeletal δ-ferrite in the welds. • Hardness and corrosion resistance were improved by multipass welding. • The best joint properties were obtained after three passes welding. - Abstract: The purpose of this study was to discuss the effect of single pass and multipass (double and triple pass) gas tungsten arc welding (GTAW) on microstructure, hardness and corrosion behavior of 304L stainless steel. In this investigation, 308 stainless steel filler metal was used. Microstructures and hardness of the weldments were investigated using optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction analysis (XRD) and Vickers microhardness (HV0.5). A ferritescope was also used in the non-destructive evaluation to observe the ferrite content on the weldments. Corrosion behavior of weldments in 1 M H2SO4 solution at 25 ± 1 °C was investigated using potentiodynamic polarization and immersion tests. Results indicated that the microstructure of fusion zones exhibited dendritic structure contained lathy and skeletal δ-ferrite. The contents of δ-ferrite in the weld zone increased by increasing the number of passes. Therefore, as the number of passes increased, the hardness and corrosion resistance increased

  2. Microstructure and Mechanical Properties of Hybrid Welded Joints with Laser and CO2-Shielded Arc

    Science.gov (United States)

    Wahba, M.; Mizutani, M.; Katayama, S.

    2016-07-01

    With the objective of reducing the operating costs, argon-rich shielding gas was replaced by 100% CO2 gas in hybrid laser-arc welding of shipbuilding steel. The welding parameters were optimized to obtain buried-arc transfer in order to mitigate spatter formation. Sound butt joints could be successfully produced for plates of 14 and 17 mm thickness in one welding pass. Subsequently, the welded joints were subjected to different tests to evaluate the influence of CO2 shielding gas on the mechanical properties of the welded joints. All tensile-tested specimens failed in the base material, indicating the higher strength of the welded joints. The impact toughness of the welded joints, measured at -20 °C, reached approximately 76% of that of the base material, which was well above the limit set by the relevant standard. The microstructure of the fusion zone consisted of grain boundary ferrite and acicular ferrite uniformly over the plate thickness except for the joint root where the microstructure was chiefly ferrite with an aligned second phase. This resulted in higher hardness in the root region compared with the top and middle parts of the fusion zone.

  3. Analysis and application of partial least square regression in arc welding process

    Institute of Scientific and Technical Information of China (English)

    YANG Hai-lan; CAI Yan; BAO Ye-feng; ZHOU Yun

    2005-01-01

    Because of the relativity among the parameters, partial least square regression(PLSR)was applied to build the model and get the regression equation. The improved algorithm simplified the calculating process greatly because of the reduction of calculation. The orthogonal design was adopted in this experiment. Every sample had strong representation, which could reduce the experimental time and obtain the overall test data. Combined with the formation problem of gas metal arc weld with big current, the auxiliary analysis technique of PLSR was discussed and the regression equation of form factors (i.e. surface width, weld penetration and weld reinforcement) to process parameters(i.e. wire feed rate, wire extension, welding speed, gas flow, welding voltage and welding current)was given. The correlativity structure among variables was analyzed and there was certain correlation between independent variables matrix X and dependent variables matrix Y. The regression analysis shows that the welding speed mainly influences the weld formation while the variation of gas flow in certain range has little influence on formation of weld. The fitting plot of regression accuracy is given. The fitting quality of regression equation is basically satisfactory.

  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. Narrow groove gas tungsten arc welding of ASTM A508 Class 4 steel for improved toughness properties

    Energy Technology Data Exchange (ETDEWEB)

    Penik, M.A. Jr. [Rensselaer Polytechnic Inst., Troy, NY (United States)

    1997-04-01

    Welding of heavy section steel has traditionally used the automatic submerged arc welding (ASAW) process because of the high deposition rates achievable. However, the properties, particularly fracture toughness, of the weld are often inferior when compared to base material. This project evaluated the use of narrow groove gas tungsten arc welding (GTAW) to improve weld material properties. The welding procedures were developed for ASTM A508 Class 4 base material using a 1% Ni filler material complying to AWS Specification A.23-90-EF3-F3-N. A narrow groove joint preparation was used in conjunction with the GTAW process so competitive fabrication rates could be achieved when compared to the ASAW process. Weld procedures were developed to refine weld substructure to achieve better mechanical properties. Two heaters of weld wire were used to examine the effects of minor filler metal chemistry differences on weld mechanical properties. Extensive metallographic evaluations showed excellent weld quality with a refined microstructure. Chemical analysis of the weld metal showed minimal weld dilution by the base metal. Mechanical testing included bend and tensile tests to ensure weld quality and strength. A Charpy impact energy curve versus temperature and fracture toughness curve versus temperature were developed for each weld wire heat. Results of fracture toughness and Charpy impact testing indicated an improved transition temperature closer to that of the base material properties.

  6. The influence of electric ARC activation on the speed of heating and the structure of metal in welds

    Directory of Open Access Journals (Sweden)

    Savytsky Oleksandr M.

    2016-01-01

    Full Text Available This paper presents the results of a research related to the impact of electric arc activation onto drive welding energy and metal weld heating speed. It is confirmed that ATIG and AMIG methods, depending on metal thickness, single pass weldability and chemical composition of activating flux, enable the reduction of welding energy by 2-6 times when compared to conventional welding methods. Additionally, these procedures create conditions to increase metal weld heating speed up to 1,500-5,500°C/s-1. Steel which can be rapidly heated, allows for a hardened structure to form (with carbon content up to 0.4%, together with a released martensitic structure or a mixture of bainitic-martensitic structures. Results of the research of effectiveness of ATIG and AMIG welding showed that increase in the penetration capability of electric arc, which increases welding productivity, is the visible side of ATIG and AMIG welding capabilities.

  7. Gas Metal Arc Welding and Flux-Cored Arc Welding. Third Edition. Teacher Edition [and] Student Edition [and] Student Workbook.

    Science.gov (United States)

    Knapp, John; Harper, Eddie

    This packet, containing a teacher's edition, a student edition, and a student workbook, introduces students to high deposition welding and processes for "shielding" a weld. In addition to general information, the teacher edition consists of introductory pages and teacher pages, as well as unit information that corresponds to the materials in the…

  8. Microstructural characterization and grain refinement of AA6082 gas tungsten arc welds by scandium modified fillers

    International Nuclear Information System (INIS)

    The refinement in weld metal grain size and shape results in both improved mechanical properties (ductility and toughness) as well as a significant improvement in weldability. In the present study, the influence of scandium (Sc) additions to the fillers on the structure and mechanical properties of AA6082 gas tungsten arc (GTA) weldments were investigated. Controlled amounts of scandium as grain refiner were introduced into the molten pool of AA6082 by pre-deposited cast inserts (AA4043 and AA5356) by GTA welding. Full penetration GTA welds were prepared using alternating current (AC). It was observed that grain size decreased with increasing amounts of scandium. The grain refinement is mainly caused by the Al3Sc particles, which act as heterogeneous nucleation of α-Al grains. It has been shown that welds prepared with AA5356 cast insert exhibited high strength and ductility when compared with other welds. The observed grain refinement was shown to result in an appreciable increase in fusion zone hardness, strength and ductility. Post-weld aging treatment resulted in improved tensile strength and hardness of the weldments and this aging response could be attributed to the weld dilution from the base metal. The slow diffusion of Sc in Al matrix and stability of Al3Sc precipitates at elevated temperatures were suggested to be responsible for the improved high temperature yield strength of welds made from Sc modified fillers. -- Highlights: ► Primary Al3Sc particles resulted in grain refinement by heterogeneous nucleation. ► Weld metal strength and hardness improved due to grain refinement caused by Sc. ► Weld metal responded to post-weld aging treatment due to dilution from base metal. ► Sc addition improved the high temperature mechanical properties of welds.

  9. 可夹持焊枪的氩弧焊自动焊接装置%Argon Arc Welding Automatic Welding Device with Clamping Welding Torch

    Institute of Scientific and Technical Information of China (English)

    张春红; 高开熠; 张宁; 常浩; 陈志伟

    2014-01-01

    针对人工焊接时由于焊接接头的熔深不同、焊缝宽度不同以及焊缝各处差异等人为因素所导致的焊接缺陷,设计了一种可夹持焊枪的氩弧焊自动焊接装置。介绍了可夹持焊枪的氩弧焊自动焊接装置的机械结构、控制模块及功能。该装置保证了稳定的焊接速度和焊接高度,实现了焊枪的三维移动和焊接过程的自动化,提高了焊接效率和焊接质量。利用此装置进行氩弧熔覆耐磨复合涂层的验证试验,试验结果表明该装置可实现组织均匀且与基底实现冶金结合的复合涂层,熔覆层硬度是基体Q235钢的6.4倍,耐磨性和表面质量良好。%During manual welding, aiming at the different fusion of welded joint, weld seam width and weld difference etc. factors which can cause welding defects, a kind of argon arc automatic welding device with clamping welding torch was designed. In this article, it introduced mechanical structure, control module and function of this device. This device can ensure stable welding speed and welding height, realize three-dimension movement of welding torch and welding process automation, and can increase welding efficiency and welding quality. Using this device to conduct verification test for argon arc cladding wear-resistant composite coating, the test results showed that the device can realize uniform organization and base metallurgical bonding confound coating, the coating layer hardness is 6.4 times that of the substrate Q235 steel, wear resistance and surface quality are good.

  10. Recent progress on gas tungsten arc welding of vanadium alloys

    International Nuclear Information System (INIS)

    This is a progress report on a continuing research project to acquire a fundamental understanding of the metallurgical processes in the welding of vanadium alloys. It also has the goal of developing techniques for welding structural vanadium alloys. The alloy V-4Cr-4Ti is used as a representative alloy of the group; it is also the prime candidate vanadium alloy for the U.S. Fusion Program at the present time. However, other alloys of this class were used in the research as necessary. The present work focuses on recent findings of hydrogen embrittlement found in vanadium alloy welds. It was concluded that the atmosphere in the inert gas glove box was insufficient for welding 6mm thick vanadium alloy plates

  11. Relationship between geometric welding parameters and optical-acoustic emissions from electric arc in GMAW-S process

    Directory of Open Access Journals (Sweden)

    E. Huanca Cayo

    2011-05-01

    Full Text Available Purpose: Show the relationship between geometric characteristics of the weld bead and the optical-acoustic emissions from electric arc during welding in the GMAW-S process.Design/methodology/approach: Bead on plate welding experiments was carried out setting different process parameters. Every welding parameter group was set aiming to reach a high stability level what guarantee a geometrical uniformity in the weld beads. In each experiment was simultaneously acquired arc voltage, welding current, infrared and acoustic emissions; from them were computed parameters as arc power, acoustic peaks rate and infrared radiation rate. It was used a tri-dimensional LASER scanner for to acquire geometrical information from the weld beads surface as width and height of the bead. Depth penetration was measured from sectional cross cutting of weld beads.Findings: Previous analysis showed that the arc emission parameters reach a stationary state with different characteristic for each experiment group which means that there is some correlation level between them. Posterior analysis showed that from infrared parameter is possible to monitoring external weld bead geometry and principally its penetration depth. From acoustic parameter is possible to monitoring principally the external weld bead geometry. Therefore is concluded that there is a close relation between the arc emissions and the weld bead geometry and that them could be used to measuring the welding geometrical parameters.Research limitations/implications: After analysis it was noticed that the infrared sensing has a better performance than acoustic sensing in the depth penetration monitoring. Infrared sensing also sources some information about external geometric parameters that in conjunction with the acoustic sensing is possible to have reliable information about weld bead geometry. This method of sensing geometric parameters could be applied in other welding processes, but is necessary to have

  12. Gas tungsten arc and laser beam welding processes effects on duplex stainless steel 2205 properties

    International Nuclear Information System (INIS)

    Highlights: ► LBW results in considerable variation in the ferrite–austenite balance of FZ. ► LBW produces smaller FZ size than GTAW. ► The effect of FZ size is more pronounced than that of ferrite–austenite balance. ► Satisfactory mechanical properties were obtained using both GTAW and LBW. ► LBW process has produced welded joint properties comparable to BM. - Abstract: A comparative study on the influence of gas tungsten arc welding (GTAW) and carbon dioxide laser beam welding (LBW) processes on the size and microstructure of fusion zone FZ then, on the mechanical and corrosion properties of duplex stainless steel DSS grade 2205 plates of 6.4 mm thickness was investigated. Autogenous butt welded joints were made using both GTAW and LBW. The GTA welded joint was made using well established welding parameters (i.e., current ampere of 110 A, voltage of 12 V, welding speed of 0.15 m/min and argon shielding rate of 15 l/min). While optimum LBW parameters were used (i.e., welding speed of 0.5 m/min, defocusing distance of 0.0 mm, argon shielding flow rate of 20 l/min and maximum output laser power of 8 kW). The results achieved in this investigation disclose that welding process play an important role in obtaining satisfactory weld properties. In comparison with GTAW, LBW has produced welded joint with a significant decrease in FZ size and acceptable weld profile. The ferrite–austenite balance of both weld metal WM and heat affected zone (HAZ) are influenced by heat input which is a function of welding process. In comparison with LBW, GTAW has resulted in ferrite–austenite balance close to that of base metal BM due to higher heat input in GTAW. However, properties of LB welded joint, particularly corrosion resistance are much better than that of GTA welded joint. The measured corrosion rates for LBW and GTAW joints are 0.05334 mm/year and 0.2456 mm/year, respectively. This is related to the relatively small size of both WM and HAZ produced in the case

  13. Gas tungsten arc and laser beam welding processes effects on duplex stainless steel 2205 properties

    Energy Technology Data Exchange (ETDEWEB)

    Mourad, A-H.I., E-mail: ahmourad@uaeu.ac.ae [Mechanical Engineering Department, Faculty of Engineering, United Arab Emirates University, Al-Ain, P.O. Box. 17555 (United Arab Emirates); Khourshid, A.; Sharef, T. [Mechanical Design and Production Department, Faculty of Engineering, Tanta University, Tanta (Egypt)

    2012-07-15

    Highlights: Black-Right-Pointing-Pointer LBW results in considerable variation in the ferrite-austenite balance of FZ. Black-Right-Pointing-Pointer LBW produces smaller FZ size than GTAW. Black-Right-Pointing-Pointer The effect of FZ size is more pronounced than that of ferrite-austenite balance. Black-Right-Pointing-Pointer Satisfactory mechanical properties were obtained using both GTAW and LBW. Black-Right-Pointing-Pointer LBW process has produced welded joint properties comparable to BM. - Abstract: A comparative study on the influence of gas tungsten arc welding (GTAW) and carbon dioxide laser beam welding (LBW) processes on the size and microstructure of fusion zone FZ then, on the mechanical and corrosion properties of duplex stainless steel DSS grade 2205 plates of 6.4 mm thickness was investigated. Autogenous butt welded joints were made using both GTAW and LBW. The GTA welded joint was made using well established welding parameters (i.e., current ampere of 110 A, voltage of 12 V, welding speed of 0.15 m/min and argon shielding rate of 15 l/min). While optimum LBW parameters were used (i.e., welding speed of 0.5 m/min, defocusing distance of 0.0 mm, argon shielding flow rate of 20 l/min and maximum output laser power of 8 kW). The results achieved in this investigation disclose that welding process play an important role in obtaining satisfactory weld properties. In comparison with GTAW, LBW has produced welded joint with a significant decrease in FZ size and acceptable weld profile. The ferrite-austenite balance of both weld metal WM and heat affected zone (HAZ) are influenced by heat input which is a function of welding process. In comparison with LBW, GTAW has resulted in ferrite-austenite balance close to that of base metal BM due to higher heat input in GTAW. However, properties of LB welded joint, particularly corrosion resistance are much better than that of GTA welded joint. The measured corrosion rates for LBW and GTAW joints are 0.05334 mm

  14. Fatigue cracking of hybrid plasma gas metal arc welded 2205 duplex stainless steel

    Energy Technology Data Exchange (ETDEWEB)

    Yurtisik, Koray; Tirkes, Suha [Middle East Technical Univ., Ankara (Turkey). Welding Technology and Nondestructive Testing Research/Application Center

    2014-10-01

    Contrary to other keyhole welding applications on duplex stainless steels, a proper cooling time and a dilution were achieved during hybrid plasma gas metal arc welding that provided sufficient reconstructive transformation of austenite without sacrificing its high efficiency and productivity. Simultaneous utilization of keyhole and metal deposition in the hybrid welding procedure enabled us to get an as-welded 11 mm-thick standard duplex stainless steel plate in a single pass. Metallographic examination on hybrid plasma-gas metal arc weldments revealed only primary austenite in ferrite matrix, whereas in addition to reconstructive transformation of primary austenite during solidification, secondary austenite was also transformed in a displacive manner due to successive thermal cycles during multi-pass gas metal arc welding. On the one hand, secondary austenite provided barriers and retarded the crack propagation during the tests in laboratory air. On the other hand, chromium and molybdenum depletion in the neighborhood of secondary austenite precipitates yielded relatively high crack propagation rates in multi-pass weldments under chloride attack.

  15. Fatigue cracking of hybrid plasma gas metal arc welded 2205 duplex stainless steel

    International Nuclear Information System (INIS)

    Contrary to other keyhole welding applications on duplex stainless steels, a proper cooling time and a dilution were achieved during hybrid plasma gas metal arc welding that provided sufficient reconstructive transformation of austenite without sacrificing its high efficiency and productivity. Simultaneous utilization of keyhole and metal deposition in the hybrid welding procedure enabled us to get an as-welded 11 mm-thick standard duplex stainless steel plate in a single pass. Metallographic examination on hybrid plasma-gas metal arc weldments revealed only primary austenite in ferrite matrix, whereas in addition to reconstructive transformation of primary austenite during solidification, secondary austenite was also transformed in a displacive manner due to successive thermal cycles during multi-pass gas metal arc welding. On the one hand, secondary austenite provided barriers and retarded the crack propagation during the tests in laboratory air. On the other hand, chromium and molybdenum depletion in the neighborhood of secondary austenite precipitates yielded relatively high crack propagation rates in multi-pass weldments under chloride attack.

  16. Critical Analysis of Moving Heat Source Shape for ARC Welding Process of High Deposition Rate

    Czech Academy of Sciences Publication Activity Database

    Ghosh, A.; Hloch, Sergej; Chattopadhyaya, S.

    2014-01-01

    Roč. 21, č. 1 (2014), s. 95-98. ISSN 1330-3651 Institutional support: RVO:68145535 Keywords : Gaussian heat distribution * oval heat source shape * Submerged Arc Welding Subject RIV: JQ - Machines ; Tools Impact factor: 0.579, year: 2014 http://hrcak.srce.hr/index.php?show=clanak&id_clanak_jezik=172337

  17. Detection and location of artificial defects during submerged-arc welding

    International Nuclear Information System (INIS)

    Using the acoustic emission source location system LOCAMAT 32 developed at CEA (France), artificial defects (flaws) were successfully detected and located during submerged-arc welding of A533B steel plates. More than 1000 events per pass were detected by each group of 4 sensors. The significant events were sorted out, considering their origin in time and space

  18. Microstructure and mechanical properties of laser-arc hybrid welding joint of GH909 alloy

    Science.gov (United States)

    Liu, Ting; Yan, Fei; Liu, Sang; Li, Ruoyang; Wang, Chunming; Hu, Xiyuan

    2016-06-01

    In this paper, laser-arc hybrid welding of 10 mm thick low-thermal-expansion superalloy GH909 components was carried out to obtain a joint with good performance. This investigation was conducted using an optical microscope, scanning electron microscope, energy diffraction spectrum and other methodologies. The results showed that weld joints with a desirable wineglass-shaped weld profile can be obtained employing appropriate process parameters. The different grains in between the upper central seam and the bottom seam were associated with the temperature gradient, the pool's flow and the welding thermal cycle. MC-type carbides and eutectic phases (γ+Laves) were produced at grain boundaries due to the component segregation during the welding process. In addition, γ‧ strengthening phase presented in the interior of grains, which kept a coherent relationship with the matrix. The lowest hardness value occurred in the weld center, which indicated that it was the weakest section in the whole joint. The average tensile strength of the joints reached to 632.90 MPa, nearly 76.84% of the base metal. The fracture analysis revealed that the fracture mode of the joint was ductile fracture and the main reason for joint failure was as a result of the occurrence of porosities produced in the weld during the welding process.

  19. Tests of arc-welding-related EMI effects on startup instrumentation

    International Nuclear Information System (INIS)

    The tests described in this paper were conducted to characterize the effects that electromagnetic interference (EMI), from arc welding, has on startup instrumentation (SUI). This paper reviews the results of a literature search on EMI resulting from arc welding and gives the objective and scope of the tests conducted and describes the test equipment and setting, and test procedure and results. Are-welding-related EMI levels in an SUI system were measured to determine the dominant source of interference, the coupling path and the susceptible part of the SUI system. The effectiveness of easily implemented improvements in reducing the level of EMI in the SUI system were also tested. Recommendations are provided on how to eliminate or reduce the EMI effects on sensitive nuclear instruments. (author)

  20. Study on general inverse kinematics of rotating/tilting positioner for robotic arc welding off-line programming

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Off-line programming provides an essential link between CAD and CAM, whose development will result in greater use of robotic arc welding. An arc welding system with a robot and a rotating/tilting positioner is one of the most typical workcells. The inverse kinematics of robot and positioner is the foundation of the off-line programming system. The previous researchers only focused on a special solution of the positioner inverse kinematics, which is the solution at down-hand welding position. In this paper, we introduce a method for representing welding position. Then a general algorithm of rotating/tilting positioner inverse kinematics is presented, and an approach to find the unique solution of the inverse kinematics is discussed. The simulation experiment results show that the general algorithm can improve the ability of robotic arc welding off-line programming system to program all types of welding positions.

  1. Factors affecting the hydrogen content of weld metal deposited by flux cored arc welding consumables

    International Nuclear Information System (INIS)

    This paper present the results of an investigation of weld metal diffusible hydrogen levels in a range of flux cored wired suitable for welding of C and C-Mn steels. Both basis and rutile wires have been investigated to assess the effect of the heat input (achieved by altering welding current and traverse speed), the contact-tip to workpiece distance (CTWD), the shielding gas type and the atmospheric exposure of the wires. The main focus of the project is to expand the current knowledge of hydrogen assisted cold cracking (HACC) in flux cored wires. The paper reports the results of diffusible hydrogen levels in single run bead-on-plate welds as a function of welding conditions. This work is a contribution to the aim of defining industrial welding conditions which minimise or eliminate the risk of HACC in weld metal deposited by flux cored wires

  2. Optimization of Weld Bead Parameters of Nickel Based Overlay Deposited by Plasma Transferred Arc Surfacing with Adequacy Test

    Directory of Open Access Journals (Sweden)

    Bhaskarananda Dasgupta

    2014-07-01

    Full Text Available Plasma Transferred Arc surfacing is a kind of Plasma Transferred Arc Welding process. Plasma Transferred Arc surfacing (PTA is increasingly used in applications where enhancement of wear, corrosion and heat resistance of materials surface is required. The shape of weld bead geometry affected by the PTA Welding process parameters is an indication of the quality of the weld. In this paper the analysis and optimization of weld bead parameters, during deposition of a Nickel based alloy Colmonoy on stainless steel plate by plasma transferred arc surfacing, are made and values of process parameters to produce optimal weld bead geometry are estimated. The experiments are conducted based on a five input process parameters and mathematical models are developed using multiple regression technique. The direct effects of input process parameters on weld bead geometry are discussed using graphs. Finally, optimization of the weld bead parameters, that is minimization of penetration and maximization of reinforcement and weld bead width, are made with a view to economize the input process parameters to achieve the desirable welding joint.

  3. Dynamic Arc-Flags in Road Networks

    OpenAIRE

    D 'angelo, Gianlorenzo; Frigioni, Daniele; Vitale, Camillo

    2011-01-01

    International audience In this work we introduce a new data structure, named Road-Signs, which allows us to efficiently update the Arc-Flags of a graph in a dynamic scenario. Road-Signs can be used to compute Arc-Flags, can be efficiently updated and do not require large space consumption for many real-world graphs like, e.g., graphs arising from road networks. In detail, we define an algorithm to preprocess Road-Signs and an algorithm to update them each time that a weight increase operat...

  4. A comparative study of the microstructure and mechanical properties of HTLA steel welds obtained by the tungsten arc welding and resistance spot welding

    International Nuclear Information System (INIS)

    Highlights: ► Hardness mapping is a novel method to identify different phases. ► Surface hardness mapping, tabulates the hardness of a large area of weld. ► Hardness maps can be used to depict the strength map through the specimen. ► Hardness mapping is an easy way to identify the phase fractions within the specimen. - Abstract: Hardness tests are routinely employed as simple and efficient methods to investigate the microstructure and mechanical properties of steels. Each microstructural phase in steel has its own hardness level. Therefore, using surface hardness mapping data over a large area of weld zone would be a reasonable method to identify the present phases in steel. The microstructure distribution and mechanical properties variation through welded structures is inhomogeneous and not suitable for certain applications. So, studying the microstructure of weld zone has a significant importance. 4130 steel is classified in HTLA steels and it is widely used in marine industry due to its superior hardenability, good corrosion resistance and high strength. Gas tungsten arc and resistance spot welding are the most usable processes in joining of 4130 sheets. In this work a series of welds have been fabricated in 4130 steel tube by gas tungsten arc and resistance spot welding. The tube was subjected to quench-tempered heat treatment. Slices from the welds before and after heat treatment were polished and etched and the macrostructure and microstructure were observed. Hardness maps were then determined over the large area of weld zone, including the heat affected zone and base plate. Results show good relations between the various microstructures, strength and hardness values. It is also proved that this method is precise and applicable to estimate phase fraction of each phase in various regions of weld. In the current study some equations were proposed to calculate the ultimate tensile stress and yield stress from the weld. The calculated data were compared

  5. Effect of laser parameters on arc behavior of laser-TIG double-side welding for aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Miao Yugang; Li Liqun; Zhang Xinge; Chen Yanbin; Wu Lin

    2010-01-01

    The influence of laser parameters on arc behavior of laser-TIG double-side welding was investigated by utilizing CCD sensor and image processing methods. It was found that arc images had an obvious transformation from laser preheating to laser plasma ejected from the keyhole bottom, resulting in the phenomena of arc column convergence and arc root constriction. The attraction phenomenon of the laser and the arc is also found in laser-TIG double-side welding. More noteworthy is that the behavior of arc attraction or constriction became much obvious at a lower current or laser plasma ejected from the keyhole bottom. The decrease in arc voltage had a certain relation with the improvement of arc stability.

  6. Arc welding quality monitoring by means of near infrared imaging spectroscopy

    Science.gov (United States)

    Garcia-Allende, P. B.; Mirapeix, J.; Cobo, A.; Conde, O. M.; Lopez-Higuera, J. M.

    2008-03-01

    The search for an efficient on-line monitoring system focused on the real-time analysis of the welding quality is an active area of research, mainly due to the widespread use of both arc and laser welding processes in relevant industrial scenarios such as aeronautics or nuclear. In this work, an improvement in the performance of a previously designed monitor system is presented. This improvement is accomplished by the employment of a dual spatial-spectral technique, namely imaging spectroscopy. This technique allows the simultaneous determination of the optical spectrum components and the spatial location of an object in a surface. In this way, the spatially characterization of the plasma emitted during a tungsten inert gas (TIG) welding is performed. The main advantage of this technique is that the spectra of all the points in the line of vision are measured at the same time. Not only are all the spectra captured simultaneously, but they are also processed as a batch, allowing the investigation of the welding quality. Moreover, imaging spectroscopy provides the desired real-time operation. To simultaneously acquire the information of both domains, spectral and spatial, a passive Prism-Grating-Prism (PGP) device can be used. In this paper the plasma spectra is captured during the welding test by means of a near infrared imaging spectroscopic system which consists of input optics, an imaging spectrograph and a monochrome camera. Technique features regarding on-line welding quality monitoring are discussed by means of several experimental welding tests.

  7. Interfacial welding of dynamic covalent network polymers

    Science.gov (United States)

    Yu, Kai; Shi, Qian; Li, Hao; Jabour, John; Yang, Hua; Dunn, Martin L.; Wang, Tiejun; Qi, H. Jerry

    2016-09-01

    Dynamic covalent network (or covalent adaptable network) polymers can rearrange their macromolecular chain network by bond exchange reactions (BERs) where an active unit replaces a unit in an existing bond to form a new bond. Such macromolecular events, when they occur in large amounts, can attribute to unusual properties that are not seen in conventional covalent network polymers, such as shape reforming and surface welding; the latter further enables the important attributes of material malleability and powder-based reprocessing. In this paper, a multiscale modeling framework is developed to study the surface welding of thermally induced dynamic covalent network polymers. At the macromolecular network level, a lattice model is developed to describe the chain density evolution across the interface and its connection to bulk stress relaxation due to BERs. The chain density evolution rule is then fed into a continuum level interfacial model that takes into account surface roughness and applied pressure to predict the effective elastic modulus and interfacial fracture energy of welded polymers. The model yields particularly accessible results where the moduli and interfacial strength of the welded samples as a function of temperature and pressure can be predicted with four parameters, three of which can be measured directly. The model identifies the dependency of surface welding efficiency on the applied thermal and mechanical fields: the pressure will affect the real contact area under the consideration of surface roughness of dynamic covalent network polymers; the chain density increment on the real contact area of interface is only dependent on the welding time and temperature. The modeling approach shows good agreement with experiments and can be extended to other types of dynamic covalent network polymers using different stimuli for BERs, such as light and moisture etc.

  8. Gravitational effects on weld pool shape and microstructural evolution during gas tungsten arc and laser beam welding on 304 stainless steel, nickel, and aluminum-4 wt.% copper alloy

    Science.gov (United States)

    Kang, Namhyun

    The objective of the present work was to investigate effects of gravitational (acceleration) level and orientation on Ni 200 alloy (99.5% Ni purity), 304 stainless steel, and Al-4 wt.% Cu alloy during gas tungsten arc welding (GTAW) and laser beam welding (LBW). Main characterization was focused on the weld pool shape, microstructure, and solute distribution as a function of gravitational level and orientation. The welds were divided into two classes, i.e., 'stable' and 'unstable' welds, in view of the variation of weld pool shape as a function of gravitational level and orientation. In general, higher arc current and translational GTAW produced more significant effects of gravitational orientation on the weld pool shape than the case of lower arc current and spot welding. Cross-sectional area (CSA) was a secondary factor in determining the stability of weld pool shape. For the 'stable' weld of 304 stainless steel GTAW, the II-U weld showed less convexity in the pool bottom and more depression of the free surface, therefore producing deeper penetration (10--20%) than the case of II-D weld. The II-D weld of 304 stainless steel showed 31% deeper penetration, 28% narrower width, and more hemispherical shape of the weld pool than the case of II-U weld. For GTAW on 304 stainless steel, gravitational level variation from low gravity (LG ≈ 1.2 go) to high gravity (HG ≈ 1.8 go) caused 10% increase in width and 10% decrease in depth while maintaining the overall weld pool volume. Furthermore, LBW on 304 stainless steels showed mostly constant shape of weld pool as a function of gravitational orientation. GTAW on Ni showed similar trends of weld pool shape compared with GTAW on 304 stainless steel, i.e., the weld pool became unstable by showing more penetration in the II-D weld for slower arc translational velocity (V a) and larger weld pool size. However, the Ni weld pool shape had greater stability of the weld pool shape with respect to the gravitational orientation

  9. Laser-ultrasonic inspection of hybrid laser-arc welded HSLA-65 steel

    International Nuclear Information System (INIS)

    The hybrid laser-arc welding (HLAW) process is a relatively low heat input joining technology that combines the synergistic qualities of both the high energy density laser beam for deep penetration and the arc for wide fit-up gap tolerance. This process is especially suitable for the shipbuilding industry where thick-gauge section, long steel plates have been widely used in a butt joint configuration. In this study, preliminary exploration was carried out to detect and visualize the welding defects using laser ultrasonics combined with the synthetic aperture focusing technique (SAFT). Results obtained on 9.3 mm thick butt-welded HSLA-65 steel plates indicated that the laser-ultrasonic SAFT inspection technique can successfully detect and visualize the presence of porosity, lack of fusion and internal crack defects. This was further confirmed by X-ray digital radiography and metallography. The results obtained clearly show the potential of using the laser-ultrasonic technology for the automated inspection of hybrid laser-arc welds

  10. Laser-ultrasonic inspection of hybrid laser-arc welded HSLA-65 steel

    Science.gov (United States)

    Lévesque, D.; Rousseau, G.; Wanjara, P.; Cao, X.; Monchalin, J.-P.

    2014-02-01

    The hybrid laser-arc welding (HLAW) process is a relatively low heat input joining technology that combines the synergistic qualities of both the high energy density laser beam for deep penetration and the arc for wide fit-up gap tolerance. This process is especially suitable for the shipbuilding industry where thick-gauge section, long steel plates have been widely used in a butt joint configuration. In this study, preliminary exploration was carried out to detect and visualize the welding defects using laser ultrasonics combined with the synthetic aperture focusing technique (SAFT). Results obtained on 9.3 mm thick butt-welded HSLA-65 steel plates indicated that the laser-ultrasonic SAFT inspection technique can successfully detect and visualize the presence of porosity, lack of fusion and internal crack defects. This was further confirmed by X-ray digital radiography and metallography. The results obtained clearly show the potential of using the laser-ultrasonic technology for the automated inspection of hybrid laser-arc welds.

  11. Microstructure and Tensile Behavior of Laser Arc Hybrid Welded Dissimilar Al and Ti Alloys

    Directory of Open Access Journals (Sweden)

    Ming Gao

    2014-02-01

    Full Text Available Fiber laser-cold metal transfer arc hybrid welding was developed to welding-braze dissimilar Al and Ti alloys in butt configuration. Microstructure, interface properties, tensile behavior, and their relationships were investigated in detail. The results show the cross-weld tensile strength of the joints is up to 213 MPa, 95.5% of same Al weld. The optimal range of heat input for accepted joints was obtained as 83–98 J·mm−1. Within this range, the joint is stronger than 200 MPa and fractures in weld metal, or else, it becomes weaker and fractures at the intermetallic compounds (IMCs layer. The IMCs layer of an accepted joint is usually thin and continuous, which is about 1μm-thick and only consists of TiAl2 due to fast solidification rate. However, the IMCs layer at the top corner of fusion zone/Ti substrate is easily thickened with increasing heat input. This thickened IMCs layer consists of a wide TiAl3 layer close to FZ and a thin TiAl2 layer close to Ti substrate. Furthermore, both bead shape formation and interface growth were discussed by laser-arc interaction and melt flow. Tensile behavior was summarized by interface properties.

  12. Dry hyperbaric gas metal arc welding of subsea pipelines: experiments and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Azar, Amin S.

    2012-07-01

    Ambitions in exploration of oil and gas fields at deeper water depth require continuous investigation and maintenance. The transportation pipelines laid in deep waters are both subjected to corrosion and buckling due to environmental phenomena. They may also often undergo branching (namely hot tapping) to redirect (or add to) the transportation paths. Mechanical joints and welding are both considered as available alternatives when sectioning and replacement of the pipes at shallow waters is necessary, yet, welding is more promising for deep waters where remote operation is central. Fusion welding on the other hand comprises several technological detractions for sound operations under high ambient pressures disregarding its low cost and flexibility. The foremost detracting phenomenon in the arc welding is called 'arc root constriction', which is defined as arc geometry shrinkage under the increased pressure. Consequently, the power delivery to the weld pool at different pressure levels is a major worry. Effects of ionization and dissociation energies of different gases and mixtures, partial pressure of environmental gases including hydrogen and oxygen, gasification and degasification of the weld metal, inclusions that affect the phase transformation, absorption and desorption kinetics, oxidation and deoxidation reactions and many more are the phenomena that can possibly be altered by the gas type and ambient pressure level. Spattering and fume generation is a problematic issue since the arc is rather unstable under high pressure. Thus, seeking the effect of different chamber gas mixtures on welding parameters, final microstructure and mechanical properties is the main objective of this work.Statistical analysis of the collected voltage and current waveforms is carried out to identify the source of arc misbehavior and instability (discussed in Paper I). The stochastic parameters is related to the electrical stability and resolved into a number of varying

  13. Key technology of robotic welding (present status and future subjects of technology). Characteristic of the arc sensor and its future technology; Robot yosetsu no key technology gijutsu no genjo to shorai eno kadai. Arc sensor no tokusei to shorai gijutsu no kadai

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-10-01

    This paper describes basic characteristics of arc sensors and adaptive control of weld pool phenomena in the GMA welding. The arc sensor, utilizing the basic characteristic where change in torch height alters the current-voltage characteristics of the arc, serves for copying the groove and controlling the torch height. Therefore, to utilize the arc sensor, it is necessary to understand the dynamic characteristics of the current/voltage waveforms. The groove copy technology using the arc sensor now reaches the stage of practical use and expanded application, and thus the important future study subject is an adaptive control of weld pool. The adaptive control of the weld pool in the key hole type one-side GMA welding was studied, and it has been found that when the amount of deposition is controlled only using the wire feed rate, and the torch voltage is controlled so that the heat generation of the arc (current {times} voltage) is constant, the key hole profile and weld bead shape can be constant regardless of widely changed groove shape. The future subject is a study of the globule transition phenomenon. 30 refs., 14 figs.

  14. Microstructure and corrosion behavior of shielded metal arc-welded dissimilar joints comprising duplex stainless steel and low alloy steel

    Science.gov (United States)

    Srinivasan, P. Bala; Muthupandi, V.; Sivan, V.; Srinivasan, P. Bala; Dietzel, W.

    2006-12-01

    This work describes the results of an investigation on a dissimilar weld joint comprising a boiler-grade low alloy steel and duplex stainless steel (DSS). Welds produced by shielded metal arc-welding with two different electrodes (an austenitic and a duplex grade) were examined for their microstructural features and properties. The welds were found to have overmatching mechanical properties. Although the general corrosion resistance of the weld metals was good, their pitting resistance was found to be inferior when compared with the DSS base material.

  15. X80埋弧焊管焊接接头冲击韧性数值研究%Numerical Simulation of Welding Joints Impact Toughness for X80 Submerged Arc Welded Pipe

    Institute of Scientific and Technical Information of China (English)

    张建勋; 杨中娜; 熊庆人; 郑莉

    2011-01-01

    Aim at impact toughness of submerged arc welded pipe welding joints, it predicted HAZ structure of submerged arc welding through CCT chart and temperature field,determined HAZ mechanical property combined with microhardness,established entity model in impact test by using finite element dynamic analysis software ANSYS/LS -DYNA,and carried out numerical simulation for dynamic impact procedure of welding joints. The absorbed energies which groove located in weld,HAZ and base metal were calculated separately. It also analyzed the variation of impaet toughness.%针对管线钢埋弧焊焊接接头的冲击韧性问题,采用CCT图和温度场结合法预测了埋弧焊接HAZ组织,结合显微硬度确定了HAZ力学性能,利用有限元法ANSY/LS-DYNA显式动力学分析软件,建立了冲击试验过程的实体模型,并对焊接接头动态冲击过程进行了数值模拟.分别计算了缺口位于焊缝、HAZ以及母材时的冲击过程中的吸收功,分析了冲击韧性的变化.

  16. 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.

  17. A General Algorithm of Rotating/tilting Positioner InverseKinematics for Robotic Arc Welding Off-line Programming

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Off-line programming provides an essential link between CAD and CAM, whose development should result in greater use of robotic arc welding. An arc welding system with a robot and a rotating/tilting positioner is a major application area, where manual programming is a very tedious job. Off-line programming is a constructive way to solve the problem. The inverse kinematics algorithm of robot and positioner is the foundation of the off-line programming system. Although previously there were some researchers who studied the positioner inverse kinematics algorithm, they only focused on a special solution of the positioner inverse kinematics, which is the solution at down-hand welding position. However, in welding production, welding position other than down-hand position is also needed. A method for representing welding position was introduced. Then a general algorithm of rotating/tilting positioner inverse kinematics is presented.

  18. Parameters optimization of hybrid fiber laser-arc butt welding on 316L stainless steel using Kriging model and GA

    Science.gov (United States)

    Gao, Zhongmei; Shao, Xinyu; Jiang, Ping; Cao, Longchao; Zhou, Qi; Yue, Chen; Liu, Yang; Wang, Chunming

    2016-09-01

    It is of great significance to select appropriate welding process parameters for obtaining optimal weld geometry in hybrid laser-arc welding. An integrated optimization approach by combining Kriging model and GA is proposed to optimize process parameters. A four-factor, five-level experiment using Taguchi L25 is conducted considering laser power (P), welding current (A), distance between laser and arc (D) and traveling speed (V). Kriging model is adopted to approximate the relationship between process parameters and weld geometry, namely depth of penetration (DP), bead width (BW) and bead reinforcement (BR). The constructed Kriging model was used for parameters optimization by GA to maximize DP, minimize BW and ensure BR at a desired value. The effects of process parameters on weld geometry are analyzed. Microstructure and micro-hardness are also discussed. Verification experiments demonstrate that the obtained optimum values are in good agreement with experimental results.

  19. Study on Surface Depression of Ti-6Al-4V with Ultrahigh-Frequency Pulsed Gas Tungsten Arc Welding

    Science.gov (United States)

    Mingxuan, Yang; Zhou, Yang; Bojin, Qi

    2015-08-01

    Molten pool surface depression was observed with the arc welding process that was caused by arc pressure. It was supposed to have a significant effect on fluid in the molten pool that was important for the microstructure and joint properties. The impact of arc force was recognized as the reason for the surface depression during arc welding. The mathematical distribution of arc force was produced with the exponent and parabola models. Different models showed different concentrations and attenuations. The comparison between them was discussed with the simulation results. The volume of fluid method was picked up with the arc force distribution model. The surface depression was caused by the arc force. The geometry of the surface depression was discussed with liquid metal properties. The welding process was carried out with different pulsed frequencies. The results indicated the forced depression exists in molten pool and the geometry of depression was hugely due to the arc force distribution. The previous work calculated the depression in the center with force balance at one point. The other area of gas shielding was resistant by the reverse gravity from the feedback of liquid metal that was squeezed out. The article discusses the pressure effect with free deformation that allowed resistance of liquid and was easy to compare with different distributions. The curve profiles were studied with the arc force distributions, and exponent model was supposed to be more accurate to the as-weld condition.

  20. Joint properties of dissimilar Al6061-T6 aluminum alloy/Ti–6%Al–4%V titanium alloy by gas tungsten arc welding assisted hybrid friction stir welding

    International Nuclear Information System (INIS)

    Highlights: • Hybrid friction stir welding for Al alloy and Ti alloy joint has been carried out. • Mechanical strength of dissimilar joint by HFSW and FSW has been compared. • Microstructure of dissimilar joint by HFSW and FSW has been compared. - Abstract: Hybrid friction stir butt welding of Al6061-T6 aluminum alloy plate to Ti–6%Al–4%V titanium alloy plate with satisfactory acceptable joint strength was successfully achieved using preceding gas tungsten arc welding (GTAW) preheating heat source of the Ti alloy plate surface. Hybrid friction stir welding (HFSW) joints were welded completely without any unwelded zone resulting from smooth material flow by equally distributed temperature both in Al alloy side and Ti alloy side using GTAW assistance for preheating the Ti alloy plate unlike friction stir welding (FSW) joints. The ultimate tensile strength was approximately 91% in HFSW welds by that of the Al alloy base metal, which was 24% higher than that of FSW welds without GTAW under same welding condition. Notably, it was found that elongation in HFSW welds increased significantly compared with that of FSW welds, which resulted in improved joint strength. The ductile fracture was the main fracture mode in tensile test of HFSW welds

  1. Effects of pulse parameters on arc characteristics and weld penetration in hybrid pulse VP-GTAW of aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Cong Baoqiang; Yang Mingxuan; Qi Bojin; Wang Lexiao; Li Wei

    2010-01-01

    A novel ultrafast-convert hybrid pulse variable polarity gas tungsten arc welding process(HPVP-GTAW)is developed.High frequency pulse square-wave current which has a frequency of more than 20 kHz is exactly integrated in the positive polarity current duration.The effects of pulse current parameters on arc characteristics and weld penetration have been studied during the HPVP-GTAW process using Al-5.8 Mg alloy plates.The arc characteristics studied by arc voltage and its profile,weld penetration noted by the ratio of weld depth to width have been found to be influenced significantly by the pulse current.The experimental results show that the HPVP-GTAW process can improve the arc profile predominantly and obtain the higher weld penetration with lower heat input.The observation may help in understanding the weld characteristics with respect to variation in the pulse current parameters which may be beneficial in using the novel HPVP-GTAW process to produce the better weld quality of aluminum alloy plates.

  2. Visualizing the influence of the process parameters on the keyhole dimensions in plasma arc welding

    International Nuclear Information System (INIS)

    The keyhole status and its dimensions are critical information determining both the process quality and weld quality in plasma arc welding (PAW). It is of great significance to measure the keyhole shape and size and to correlate them with the main process parameters. In this study, a low-cost vision system is developed to visualize the keyhole at the backside of the test-pieces in PAW. Three stages of keyhole evolution, i.e. initial blind stage (non-penetrated keyhole), unstable stage with momentarily disappeared keyhole and quasi-steady open keyhole stage (fully-penetrated keyhole), are measured in real-time during the PAW tests on stainless steel test-pieces of thickness 8 mm. Based on the captured images of keyhole under different welding conditions, the correlations of the main welding process parameters (welding current, welding speed, plasma gas flow rate) with the keyhole length, width and area are visualized through vision measurement. It lays a solid foundation for implementing keyhole stability control and process optimization in keyhole PAW. (paper)

  3. [Impact of introduction of O2 on the welding arc of gas pool coupled activating TIG].

    Science.gov (United States)

    Huang, Yong; Wang, Yan-Lei; Zhang, Zhi-Guo

    2014-05-01

    In the present paper, Boltzmann plot method was applied to analyze the temperature distributions of the are plasma when the gas pool coupled activating TIG welding was at different coupling degrees with the outer gas being O2. Based on this study of temperature distributions, the changing regularities of are voltage and are appearance were studied. The result shows that compared with traditional TIG welding, the introduction of O2 makes the welding arc constricted slightly, the temperature of the are center build up, and the are voltage increase. When argon being the inner gas, oxygen serving as the outer gas instead of argon makes the are constricted more obviously. When the coupling degree increases from 0 to 2, the temperature of the are center and the are voltage both increase slightly. In the gas pool coupled activating TIG welding the are is constricted not obviously, and the reason why the weld penetration is improved dramatically in the welding of stainless steel is not are constriction. PMID:25095400

  4. XRD and DTA Analysis of Developed Agglomerated Fluxes for Submerged Arc Welding

    Directory of Open Access Journals (Sweden)

    Ajay Kumar

    2013-01-01

    Full Text Available A unique study of structural and chemical analysis of crystalline phases in developed agglomerated fluxes was carried out. Thirty-two fluxes were developed by using a mixture of oxides, halides, carbonates, silicates, and ferroalloys for submerged arc welding. The present paper focuses on only ten (out of thirty-two fluxes which were analyzed by X-ray diffraction (XRD to know the different types of oxides formed and changed in oxidation number of metallic centers after sintering process at around 850∘C. To know the effect of temperature over phase transformation and melting of different compounds, differential thermal analysis (DTA was carried out from 1000 to 1400∘C. This study aims to know the quantity of ions present (percentage and melting behavior of developed agglomerated fluxes for submerged arc welding process.

  5. Welding stability assessment in the GMAW-S process based on fuzzy logic by acoustic sensing from arc emissions

    Directory of Open Access Journals (Sweden)

    E. Huanca Cayo

    2012-11-01

    Full Text Available Purpose: The present research work has as purpose detecting perturbations, measuring and assessing the welding stability in GMAW process in short circuit mode named hereafter as GMAW-S process.Design/methodology/approach: Welding trials were performed with a set of optimal input welding parameters. During experiments were induced some perturbations on the welding trajectory. It causes alteration on the stability of welding resulting as consequence geometrical shape deformations. During each experiments, acoustic emission signal coming from electric arc as well as arc voltage and welding current were acquired aided by a card acquisition and virtual instrumentation software. A heuristic model was performed as knowledge base rules of a fuzzy logic system. This system has two inputs and one output. Some additional welding trials were performed for assessing its performance.Findings: It was performed a welding stability assessment system based on fuzzy logic. As well as, this system is based on non-contact sensing what reduces the loading effects on the welding process.Research limitations/implications: In the present work was monitored just the acoustic emissions coming from arc. Although that, the results were satisfactory, an approach on data fusion of sensors including electromagnetic emission sensors could improve the quality assessments system.Originality/value: The non-contact welding stability assessment methods have reduces loading effects and a heuristic approach on the relations between arc emissions and welding stability allows quantifying nonlinear variables such as knowledge and experience of skilled welders, such that, it is possible to represent linguistic terms numerically what could be used as an on-line monitoring system of welding processes.

  6. Effect Of Pulsed Current Micro Plasma Arc Welding Process Parameters On Fusion Zone Grain Size And Ultimate Tensile

    OpenAIRE

    Kondapalli Siva Prasad; Chalamalasetti Srinivasa Rao; Damera Nageswara Rao

    2012-01-01

    AISI 304L is an austenitic Chromium-Nickel stainless steel offering the optimum combination of corrosion resistance, strength and ductility. These attributes make it a favorite for many mechanical components. The low carbon content reduces susceptibility to carbide precipitation during welding. In case of single pass welding of thinner section of this alloy, pulsed current micro plasma arc welding was found beneficial due to its advantages over the conventional continuous current process. The...

  7. Arc-welding process control based on back face thermography: application to the manufacturing of nuclear steam generators

    OpenAIRE

    Cobo García, Adolfo; Mirapeix Serrano, Jesús María; Conde Portilla, Olga María; García Allende, Pilar Beatriz; Madruga Saavedra, Francisco Javier; López Higuera, José Miguel

    2007-01-01

    The possibility of reducing defects in the arc welding process has attracted research interest, particularly, in the aerospace and nuclear sectors where the resulting weld quality is a major concern and must be assured by costly, time-consuming, non-destructive testing (NDT) procedures. One possible approach is the analysis of a measurand correlated with the formation of defects, from which a control action is derived. Among others, the thermographic analysis of the weld pool and the heat-aff...

  8. 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...

  9. Spectroscopic Polymer Optical Fiber sensor for orbital arc-welding on-line monitoring

    OpenAIRE

    Cobo García, Adolfo; Mirapeix Serrano, Jesús María; Valdiande Gutiérrez, José Julián; García Allende, Pilar Beatriz; Conde Portilla, Olga María; López Higuera, José MIguel

    2007-01-01

    Plasma optical spectroscopy has proved to be a promising solution for the on-line monitoring of both laser and arc-welding processes, where quality assurance plays a mayor role, especially in some particular industrial scenarios like aeronautics. Despite the robustness provided by these spectroscopic analysis techniques, the implementation of an efficient and non-invasive optical sensor system is not always feasible. Input optics based on optical collimators are commonly employed, but when co...

  10. Fatigue Crack Growth Behavior of Gas Metal Arc Welded AISI 409 Grade Ferritic Stainless Steel Joints

    Science.gov (United States)

    Lakshminarayanan, A. K.; Shanmugam, K.; Balasubramanian, V.

    2009-10-01

    The effect of filler metals such as austenitic stainless steel, ferritic stainless steel, and duplex stainless steel on fatigue crack growth behavior of the gas metal arc welded ferritic stainless steel joints was investigated. Rolled plates of 4 mm thickness were used as the base material for preparing single ‘V’ butt welded joints. Center cracked tensile specimens were prepared to evaluate fatigue crack growth behavior. Servo hydraulic controlled fatigue testing machine with a capacity of 100 kN was used to evaluate the fatigue crack growth behavior of the welded joints. From this investigation, it was found that the joints fabricated by duplex stainless steel filler metal showed superior fatigue crack growth resistance compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Higher yield strength and relatively higher toughness may be the reasons for superior fatigue performance of the joints fabricated by duplex stainless steel filler metal.

  11. Shielding and filtering techniques to protect sensitive instrumentation from electromagnetic interference caused by arc welding

    International Nuclear Information System (INIS)

    Electromagnetic interference (EMI) caused by arc welding is a concern for sensitive CANDU instrumentation and control equipment, especially start-up instrumentation (SUI) and ion chamber instruments used to measure neutron flux at low power. Measurements of the effectiveness of simple shielding and filtering techniques that may be applied to limit arc welding electromagnetic emissions below the interference threshold are described. Shielding configurations investigated include an arrangement in which the welding power supply, torch (electrode holder), interconnecting cables and welder operator were housed in a single enclosure and a more practical configuration of separate shields for the power supply, cables and operator with torch. The two configuration were found to provide 30 dB and 26 dB attenuation, respectively, for arc welder electric-field emissions and were successful in preventing EMI in SUI set up just outside the shielding enclosures. Practical improvements that may be incorporated in the shielding arrangement to facilitate quick setup in the field in a variety of application environments, while maintaining adequate EMI protection, are discussed. (author)

  12. Finite Element Simulation of Plasma Transferred ARC Welding [PTAW] of Structural Steel

    Directory of Open Access Journals (Sweden)

    PV Senthiil

    2014-10-01

    Full Text Available Plasma transferred Arc welding is one of the most widely used welding process, in which the metals are fused just above the melting point, and makes the metal to fuse. It is employed in many applications like tool die and metal casting, strip metal welding etc. This investigation is to analyze temperature distribution residual stress and distortion by varying the heat source parameter in SYSWELD, and compared the results with ANSYS. The simulation of Plasma Transferred Arc welding was of structural steel plate performed using a non-linear transient heat transfer analysis. Heat losses due to convection and variation of material properties with temperature were considered in this analysis. To incorporate the heat developed the Gaussian distribution was considered. Finite element simulations were performed using ANSYS Parametric Design Language (APDL code and using SYSWELD. The temperatures obtained were compared with experimental results for validation. It was found that the predicted values of temperature agree very well with the experimental values. Residual Stress and Distortion were also predicted for various heat Input. The effect of heat input on residual stress and distortion was investigated.

  13. Methods of calculation of weldpool surface form on the reverse side of plate under welding by impulse penetrative arc

    International Nuclear Information System (INIS)

    Model of calculating formation of camber and surface of welded point under welding by impulse penetrative arc is presented. The specific feature of the model lies in the fact, that it takes into account two simultaneous processes: metal movement to equilibrium state and crystallizatin of liquid metal of a pool . Correlation of calculation and experimental results shows the sufficient adequacy of the model and real processes. The model can be used for analyzing the process of welding by pulse penetrative arc and for evaluating camber and shape of the surface of crystallized metal in a pool

  14. Study of the welding gas influence on a controlled short-arc GMAW process by optical emission spectroscopy

    OpenAIRE

    Wilhelm, G; Gött, G; Schöpp, H; Uhrlandt, D

    2010-01-01

    Abstract The controlled short arc processes, variants of the Gas Metal Arc Welding (GMAW) process, which have recently been developed, are used to reduce the heat input into the workpiece. Such a process with a wire feeding speed which varies periodically, using a steel wire and a steel workpiece to produce bead on plate welds has been investigated. As welding gases CO 2 and a mixture of Ar and O 2 have been used. Depending on the gas the properties of the plasma change, and as a consequen...

  15. Microstructure and mechanical properties of SA508-3 steel weldments with submerged arc welding

    International Nuclear Information System (INIS)

    The present study was to investigate the effect of energy input on the microstructure, tensile properties and toughness of single-pass submerged arc bead-in-groove welds produced on RPV SA508 class 3 steels. The heat input was varied in the range of 1.6, 3.2 and 5.0 kJ/mm. The toughness of weld metals was evaluated by using subsize Charpy V-notch specimens in the temperature range of -190 .deg. C to 20 .deg. C. The weld microstructure and fractography were observed by optical and scanning electron microscopies, respectively. With increasing heat inputs, tensile strength and hardness of weld metals were decreased while elongation was increased. The poor notch toughness at 1.6 kJ/mm was attributed to the formation of ferrite with aligned second phase and banitic microstructure with high yield strength while that at 5.0 kJ/mm was due to the presence of grain boundary and polygonal ferrites. The microstructure of the intermediate energy input welds consisted of a high proportion of acicular ferrite with limited polygonal ferrites, which provide improved notch toughness

  16. Processing and structure of in situ Fe-Al alloys produced by gas tungsten arc welding

    Energy Technology Data Exchange (ETDEWEB)

    Banovic, S.W.; DuPont, J.N.; Marder, A.R. [Lehigh Univ., Bethlehem, PA (United States). Energy Research Center

    1997-02-14

    Iron aluminide weld overlays are being investigated for corrosion and erosion protection of boiler tubes in low NOx burners. The primary objective of the research is to identify overlay compositions which can be deposited in a crack-free condition and provide corrosion protection in moderately reducing environments. In the current phase of work, Fe-Al alloy weld overlays were produced by depositing commercially pure aluminum wire on to low carbon steel substrates using Gas Tungsten Arc Welding. A systematic variation of the wire feed speed and current, two major factors affecting dilution, resulted in a variation in aluminum contents of the welds ranging from 3--42 wt% aluminum. The aluminum content was observed to increase with wire feed speed and a decrease in the current. The aluminum content was also found to affect the cracking susceptibility of the overlays. At 10wt% aluminum, few to no cracks were observed in the deposits. Above this value, cracking was prevalent throughout the weld. In addition, two types of microstructures were found correlating to different concentrations of aluminum. A homogeneous matrix with second phase particles consisting of coarse columnar grains was found for low aluminum concentrations. With higher aluminum contents, a two-phase constituent was observed to surround primary dendrites growing from the substrate. The transition of the microstructures occurred between 24 and 32 wt% Al.

  17. The-state-of-the-art and the subjects of arc welding automation in vessel and pipe

    International Nuclear Information System (INIS)

    Recently, due to the shortage of skilled workers, the rationalization of production technology has become urgently necessary. Welding technology has achieved the remarkable progress, such as the functions of high precision sensing, control of welding conditions with computers, self diagnosis of the equipment and so on. As for the electric power source, the power output control changed from thyristor phase control to transistor inverter system, and it has contributed largely to the heightening of welding performance. Narrow groove MAG welding and narrow groove submerged arc welding (SAW) for vessels, and the electroslag cladding welding for the austenitic stainless steel lining of vessels are explained. Due to the progress of welding technology, the welding of piping can be done by leaving it without watch to some extent, by unskilled workers, and by operating several welding machines by one worker. Pulsed TIG welding is used for stainless steel and high alloy materials, and pulsed MAG welding is used for others. The internal bare welder for welding heat exchanger tubes and tube plates is shown. (K.I.)

  18. Optimization of Process Parameters of Hybrid Laser-Arc Welding onto 316L Using Ensemble of Metamodels

    Science.gov (United States)

    Zhou, Qi; Jiang, Ping; Shao, Xinyu; Gao, Zhongmei; Cao, Longchao; Yue, Chen; Li, Xiongbin

    2016-08-01

    Hybrid laser-arc welding (LAW) provides an effective way to overcome problems commonly encountered during either laser or arc welding such as brittle phase formation, cracking, and porosity. The process parameters of LAW have significant effects on the bead profile and hence the quality of joint. This paper proposes an optimization methodology by combining non-dominated sorting genetic algorithm (NSGA-II) and ensemble of metamodels (EMs) to address multi-objective process parameter optimization in LAW onto 316L. Firstly, Taguchi experimental design is adopted to generate the experimental samples. Secondly, the relationships between process parameters ( i.e., laser power ( P), welding current ( A), distance between laser and arc ( D), and welding speed ( V)) and the bead geometries are fitted using EMs. The comparative results show that the EMs can take advantage of the prediction ability of each stand-alone metamodel and thus decrease the risk of adopting inappropriate metamodels. Then, the NSGA-II is used to facilitate design space exploration. Besides, the main effects and contribution rates of process parameters on bead profile are analyzed. Eventually, the verification experiments of the obtained optima are carried out and compared with the un-optimized weld seam for bead geometries, weld appearances, and welding defects. Results illustrate that the proposed hybrid approach exhibits great capability of improving welding quality in LAW.

  19. Optimization of Process Parameters of Hybrid Laser-Arc Welding onto 316L Using Ensemble of Metamodels

    Science.gov (United States)

    Zhou, Qi; Jiang, Ping; Shao, Xinyu; Gao, Zhongmei; Cao, Longchao; Yue, Chen; Li, Xiongbin

    2016-04-01

    Hybrid laser-arc welding (LAW) provides an effective way to overcome problems commonly encountered during either laser or arc welding such as brittle phase formation, cracking, and porosity. The process parameters of LAW have significant effects on the bead profile and hence the quality of joint. This paper proposes an optimization methodology by combining non-dominated sorting genetic algorithm (NSGA-II) and ensemble of metamodels (EMs) to address multi-objective process parameter optimization in LAW onto 316L. Firstly, Taguchi experimental design is adopted to generate the experimental samples. Secondly, the relationships between process parameters (i.e., laser power (P), welding current (A), distance between laser and arc (D), and welding speed (V)) and the bead geometries are fitted using EMs. The comparative results show that the EMs can take advantage of the prediction ability of each stand-alone metamodel and thus decrease the risk of adopting inappropriate metamodels. Then, the NSGA-II is used to facilitate design space exploration. Besides, the main effects and contribution rates of process parameters on bead profile are analyzed. Eventually, the verification experiments of the obtained optima are carried out and compared with the un-optimized weld seam for bead geometries, weld appearances, and welding defects. Results illustrate that the proposed hybrid approach exhibits great capability of improving welding quality in LAW.

  20. The submerged-arc welding in narrow chamfer of steel DIN 20MnMoNi55 with nuclear quality

    International Nuclear Information System (INIS)

    A procedure for welding thick plates (140 mm) of steel DIN 20MnMoNi55 (ASTM A 533 grB cl1) of nuclear quality by submerged-arc process in narrow chamfer using wire S3NiMol of 0.5 mm diameter was developed. A head of specific welding was constructed, and samples were welded aiming to optimize the welding parameters and to investigate the influence of the length from wire to chamfer face in quality of joint. The joints were evaluated by mechanical and metallographic tests. The results were compared with a joint of the same thickness welded by submerged-arc process in conventional chamfer. (M.C.K.)

  1. Hybrid Laser-Arc Welding of 10-mm-Thick Cast Martensitic Stainless Steel CA6NM: As-Welded Microstructure and Mechanical Properties

    Science.gov (United States)

    Mirakhorli, Fatemeh; Cao, Xinjin; Pham, Xuan-Tan; Wanjara, Priti; Fihey, Jean-Luc

    2016-04-01

    Cast CA6NM martensitic stainless steel plates, 10 mm in thickness, were welded using hybrid laser-arc welding. The effect of different welding speeds on the as-welded joint integrity was characterized in terms of the weld bead geometry, defects, microstructure, hardness, ultimate tensile strength, and impact energy. Significant defects such as porosity, root humping, underfill, and excessive penetration were observed at a low welding speed (0.5 m/min). However, the underfill depth and excessive penetration in the joints manufactured at welding speeds above 0.75 m/min met the specifications of ISO 12932. Characterization of the as-welded microstructure revealed untempered martensite and residual delta ferrite dispersed at prior-austenite grain boundaries in the fusion zone. In addition, four different heat-affected zones in the weldments were differentiated through hardness mapping and inference from the Fe-Cr-Ni ternary phase diagram. The tensile fracture occurred in the base metal for all the samples and fractographic analysis showed that the crack path is within the martensite matrix, along primary delta ferrite-martensite interfaces and within the primary delta ferrite. Additionally, Charpy impact testing demonstrated slightly higher fracture energy values and deeper dimples on the fracture surface of the welds manufactured at higher welding speeds due to grain refinement and/or lower porosity.

  2. Hybrid Laser-Arc Welding of 10-mm-Thick Cast Martensitic Stainless Steel CA6NM: As-Welded Microstructure and Mechanical Properties

    Science.gov (United States)

    Mirakhorli, Fatemeh; Cao, Xinjin; Pham, Xuan-Tan; Wanjara, Priti; Fihey, Jean-Luc

    2016-07-01

    Cast CA6NM martensitic stainless steel plates, 10 mm in thickness, were welded using hybrid laser-arc welding. The effect of different welding speeds on the as-welded joint integrity was characterized in terms of the weld bead geometry, defects, microstructure, hardness, ultimate tensile strength, and impact energy. Significant defects such as porosity, root humping, underfill, and excessive penetration were observed at a low welding speed (0.5 m/min). However, the underfill depth and excessive penetration in the joints manufactured at welding speeds above 0.75 m/min met the specifications of ISO 12932. Characterization of the as-welded microstructure revealed untempered martensite and residual delta ferrite dispersed at prior-austenite grain boundaries in the fusion zone. In addition, four different heat-affected zones in the weldments were differentiated through hardness mapping and inference from the Fe-Cr-Ni ternary phase diagram. The tensile fracture occurred in the base metal for all the samples and fractographic analysis showed that the crack path is within the martensite matrix, along primary delta ferrite-martensite interfaces and within the primary delta ferrite. Additionally, Charpy impact testing demonstrated slightly higher fracture energy values and deeper dimples on the fracture surface of the welds manufactured at higher welding speeds due to grain refinement and/or lower porosity.

  3. RAPID COMMUNICATION: Observation of a dynamic specular weld pool surface

    Science.gov (United States)

    Zhang, Y. M.; Song, H. S.; Saeed, G.

    2006-06-01

    Observation and measurement of a weld pool surface is a key towards the development of next generation intelligent welding machines which can mimic a skilled human welder to a certain extent. However, the bright arc radiation and the specular surface complicate the observation and measurement task. This paper proposes a novel method to turn the difficulty of the specular surface into an advantage by exploiting the difference between propagation of an illumination laser and the arc plasma. The governing law is simply the reflection law which can provide the base for the computation of the weld pool surface. Experimental results verified the effectiveness of the proposed method in acquiring clear images in the presence of the bright arc.

  4. NUMERICAL MODELING OF HEAT TRANSFER AND FLUID FLOW IN KEYHOLE PLASMA ARC WELDING OF DISSIMILAR STEEL JOINTS

    Directory of Open Access Journals (Sweden)

    M. A. Daha

    2012-02-01

    Full Text Available The evolution of temperature profiles and weld pool geometry during dissimilar welding between 2205 duplex stainless steel and A36 low carbon steel using keyhole plasma arc welding has been simulated using a three dimensional numerical heat transfer and fluid flow model. An adaptive heat source is proposed as a heat source model for performing a non-linear transient thermal analysis, based on the configuration feature of keyhole plasma arc welds. Temperature profiles and solidified weld pool geometry are presented for three different welding heat input. The reversed bugle shape parameters (width of fusion zone at both top and bottom surfaces of the weld pool geometry features for a dissimilar 2205–A36 weld joint are summarized to successfully explain the observations. The model was also applied to keyhole plasma welding of 6.8 mm thick similar 2205 duplex stainless steel joint for validation. The simulation results were compared with independently obtained experimental data and good agreements have been obtained.

  5. Effect of heat input on dilution and heat affected zone in submerged arc welding process

    Indian Academy of Sciences (India)

    Hari Om; Sunil Pandey

    2013-12-01

    Submerged arc welding (SAW) is a fusion joining process, known for its high deposition capabilities. This process is useful in joining thick section components used in various industries. Besides joining, SAW can also be used for surfacing applications. Heat Affected Zone (HAZ) produced within the base metal as a result of tremendous heat of arc is of big concern as it affects the performance of welded/surfaced structure in service due to metallurgical changes in the affected region. This work was carried out to investigate the effect of polarity and other SAW parameters on HAZ size and dilution and to establish their correlations. Influence of heat input on dilution and heat affected zone was then carried out. Four levels of heat input were used to study their effect on % dilution and HAZ area at both the electrode positive and electrode negative polarities. Proper management of heat input in welding is important, because power sources can be used more efficiently if one knows how the same heat input can be applied to get the better results. Empirical models have been developed using statistical technique.

  6. On the choice of electromagnetic model for short high-intensity arcs, applied to welding

    International Nuclear Information System (INIS)

    We have considered four different approaches for modelling the electromagnetic fields of high-intensity electric arcs: (i) three-dimensional, (ii) two-dimensional axi-symmetric, (iii) the electric potential formulation and (iv) the magnetic field formulation. The underlying assumptions and the differences between these models are described in detail. Models (i) to (iii) reduce to the same limit for an axi-symmetric configuration with negligible radial current density, contrary to model (iv). Models (i) to (iii) were retained and implemented in the open source CFD software OpenFOAM. The simulation results were first validated against the analytic solution of an infinite electric rod. Perfect agreement was obtained for all the models tested. The electromagnetic models (i) to (iii) were then coupled with thermal fluid mechanics, and applied to axi-symmetric gas tungsten arc welding test cases with short arc (2, 3 and 5 mm) and truncated conical electrode tip. Models (i) and (ii) lead to the same simulation results, but not model (iii). Model (iii) is suited in the specific limit of long axi-symmetric arc with negligible electrode tip effect, i.e. negligible radial current density. For short axi-symmetric arc with significant electrode tip effect, the more general axi-symmetric formulation of model (ii) should instead be used. (paper)

  7. Detection of short circuit in pulse gas metal arc welding process

    Directory of Open Access Journals (Sweden)

    P.K.D.V. Yarlagadda

    2007-09-01

    Full Text Available Purpose: The paper discusses several methods of detecting occurrence of short circuit and short circuit severity in pulse gas metal arc welding process (GMAW-P.Design/methodology/approach: Welding experiments with different values of pulsing parameter and simultaneous recording of high speed camera pictures and welding signals (such as current and voltage were used to identify the occurrence of short circuit and its severity in GMAW-P process. The investigation is based on the measurement of welding signals specifically current and voltage signals and their synchronization with high speed camera to investigate the short circuit phenomenon in GMAW-P process.Findings: The results reveal that short circuit can be detected using signal processing techniques and its severity can be predicted by using statistical models and artificial intelligence techniques in GMAW-P process.Research limitations/implications: Several factors are responsible for short circuit occurrence in GMAW-P process. The results show that voltage and current signal carry rich information about the metal transfer and especially short circuit occurrence in GMAW-P process. Hence it’s possible to detect short circuit occurrence in GMAW-P process. Future work should concentrate on development of advance techniques to improve reliability of techniques mentioned in this paper for short circuit detection and prediction in GMAW-P process.Originality/value: For achieving atomization of the welding processes, implementation of real time monitoring of weld quality is essential. Specifically for GMAW-P process which is widely used for light weight metal which is widely gaining popularity in manufacturing industry. However, in case of GMAW-P process hardly any attempt is made to analyse techniques to detect and predict occurrence of short circuit. This paper analyses different techniques that can be employed for real time monitoring and prediction of short circuit and its severity in the

  8. Effect of aluminum on the Ti-O-B-N balance in submerged arc welding

    International Nuclear Information System (INIS)

    The arguments explaining the interplay of titanium and boron during welding essentially depend on a weld metal gas absorption/reaction phenomenon, i.e., on the Ti-O-B-N balance. Although increasing deposit nitrogen content is generally associated with inferior toughness properties, this is not always the case. Recent work has indicated that lowering deposit nitrogen content from 70 to 30 ppm can actually increase fracture appearance transition temperature (FATT) values. These results were interpreted using a model depending on the reaction sequence, Ti/O, Ti/N and B/N. Optimum toughness occurred when TiN and BN formations left an active boron content of 8 ppm at prior austenite grain boundaries. This emphasis on TiN formation prior to BN formation and the necessity of BN formation in order to prevent excess boron (and borocarbide formation) has important consequences. This paper evaluates the interaction of aluminum and nitrogen content during submerged arc welding and confirms the critical role of TiN formation in the performance of TiB-containing welding consumables

  9. Stress corrosion cracking behaviour of gas tungsten arc welded super austenitic stainless steel joints

    Directory of Open Access Journals (Sweden)

    M. Vinoth Kumar

    2015-09-01

    Full Text Available Super 304H austenitic stainless steel with 3% of copper posses excellent creep strength and corrosion resistance, which is mainly used in heat exchanger tubing of the boiler. Heat exchangers are used in nuclear power plants and marine vehicles which are intended to operate in chloride rich offshore environment. Chloride stress corrosion cracking is the most likely life limiting failure with austenitic stainless steel tubing. Welding may worsen the stress corrosion cracking susceptibility of the material. Stress corrosion cracking susceptibility of Super 304H parent metal and gas tungsten arc (GTA welded joints were studied by constant load tests in 45% boiling MgCl2 solution. Stress corrosion cracking resistance of Super 304H stainless steel was deteriorated by GTA welding due to the formation of susceptible microstructure in the HAZ of the weld joint and the residual stresses. The mechanism of cracking was found to be anodic path cracking, with transgranular nature of crack propagation. Linear relationships were derived to predict the time to failure by extrapolating the rate of steady state elongation.

  10. Digital arc welding power supply based on real-time operating system

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A digital arc welding power supply was designed with the advanced reduced instruction set computer machine (ARM) and embedded real-time multi-task operating system micro C/OS-Ⅱ. The ARM, with its powerful calculating speed and complete peripheral equipments, is very suitable to work as the controller of the digital power supply. The micro C/OS-Ⅱ transplanted in ARM, helps to improve the respondent speed against various welding signals, as well as the reliability of the controlling software. The welding process consists of nine tasks. The tasks of great significance on reliability of the welder, for example, the A/D conversion of current and voltage, enjoy top priority. To avoid simultaneous-sharing on A/D converter and LCD module, two semaphores are introduced in to ensure the smooth performance of the welding power supply. Proven by experiments,the ARM and the micro C/OS-Ⅱ can greatly improve both the respondent speed and the reliability of the digital welder.

  11. The influence of hydrogen on the fatigue behaviour of base and gas tungsten arc welded Eurofer

    International Nuclear Information System (INIS)

    Room temperature hydrogen embrittlement susceptibility of Eurofer base-metal and gas-tungsten-arc-welded joint has been investigated by fully-reversed load-control low cycle fatigue. The tests were run on specimens subjected to electrochemical charging before and during cyclic stressing. Compared to the uncharged condition, increasing amounts of hydrogen in base-steel caused fatigue life reduction by promoting premature cracking of either grain boundaries or cleavage planes. Examination of fracture morphologies indicated that the underlying embrittlement mechanisms likely correlated with plastic flow alteration and interatomic bond decohesion, both induced by hydrogen. Specimen-to-specimen response variability by test replication was accounted for in terms of Eurofer material heterogeneity, based on relevant experimental indexes. This interpretation was consistent with the well known sensitivity to microstructure of hydrogen embrittlement processes, and explained the large scatter of fatigue lives and failure modes subsequently observed in equivalently charged Eurofer weld samples

  12. The influence of hydrogen on the fatigue behaviour of base and gas tungsten arc welded Eurofer

    Science.gov (United States)

    Maday, Marie-Françoise; Pilloni, Luciano

    2007-08-01

    Room temperature hydrogen embrittlement susceptibility of Eurofer base-metal and gas-tungsten-arc-welded joint has been investigated by fully-reversed load-control low cycle fatigue. The tests were run on specimens subjected to electrochemical charging before and during cyclic stressing. Compared to the uncharged condition, increasing amounts of hydrogen in base-steel caused fatigue life reduction by promoting premature cracking of either grain boundaries or cleavage planes. Examination of fracture morphologies indicated that the underlying embrittlement mechanisms likely correlated with plastic flow alteration and interatomic bond decohesion, both induced by hydrogen. Specimen-to-specimen response variability by test replication was accounted for in terms of Eurofer material heterogeneity, based on relevant experimental indexes. This interpretation was consistent with the well known sensitivity to microstructure of hydrogen embrittlement processes, and explained the large scatter of fatigue lives and failure modes subsequently observed in equivalently charged Eurofer weld samples.

  13. Research and engineering application of the arc welding pulsed controller technology

    Institute of Scientific and Technical Information of China (English)

    Li Huan; Cui Jia; Niu Yong; Du Naicheng

    2005-01-01

    The tenacity of heat-affected zone (HAZ) will decline and the size of grains will increase, because of the overheating on HAZ when submerged arc welding (SAW) is used to thick plate with high heat input. The shaping will worsen when SAW is used to thin plate with high current at high speed. A new SAW technology, the pulsed direct current (DC)automatic SAW, will be put forward in this paper in order to overcome the above shortcomings. And a pulsed controller with micro-controller unit (MCU) as the core, nixie tube (NT) and keyboard as the man-machine conversation interface is developed. The main functions of the pulsed controller include the output of pulsed welding current and the working with twinwire. The research has widely prospects in application with significant meanings in theory and practical engineering.

  14. An approach to measure the pose of RHJD4-1 arc welding robot for calibration

    Institute of Scientific and Technical Information of China (English)

    宋月娥; 吴林; 田劲松; 戴明

    2002-01-01

    A measurement setup used for robot calibration was designed to meet the requirement of off-line programming technique. The robot end-effector pose (position and orientation) can be calculated indirectly by using this setup. The setup has been applied to RHJD4-1 arc welding robot. The experimental results show the method of pose measuring using the measurement setup is simple and reliable to finish pose measuring for robot calibration. In addition, the setup can measure the position repeatability of robot.

  15. Study on chaos in short circuit gas metal arc welding process

    Institute of Scientific and Technical Information of China (English)

    Lü Xiaoqing; Cao Biao; Zeng Min; Wang Zhenmin; Huang Shisheng

    2007-01-01

    Based on the chaos theory, an idea is put forward to analyze the short circuit Gas Metal Arc Welding (GMAW-S) process. The theory of phase space reconstruction and related algorithms such as mutual information and so on, are applied to analyze the chaos of the GMAW-S process. The largest Lyapunov exponents of some current time series are calculated, and the results indicate that chaos exists in the GMAW-S process. The research of the chaos in the GMAW-S process can be help to get new knowledge of the process.

  16. Dynamic simulations of tissue welding

    Energy Technology Data Exchange (ETDEWEB)

    Maitland, D.J.; Eder, D.C.; London, R.A.; Glinsky, M.E. [and others

    1996-02-01

    The exposure of human skin to near-infrared radiation is numerically simulated using coupled laser, thermal transport and mass transport numerical models. The computer model LATIS is applied in both one-dimensional and two-dimensional geometries. Zones within the skin model are comprised of a topical solder, epidermis, dermis, and fatty tissue. Each skin zone is assigned initial optical, thermal and water density properties consistent with values listed in the literature. The optical properties of each zone (i.e. scattering, absorption and anisotropy coefficients) are modeled as a kinetic function of the temperature. Finally, the water content in each zone is computed from water diffusion where water losses are accounted for by evaporative losses at the air-solder interface. The simulation results show that the inclusion of water transport and evaporative losses in the model are necessary to match experimental observations. Dynamic temperature and damage distributions are presented for the skin simulations.

  17. Pojavi pri varjenju z večžično elektrodo za povečanje talilnega učinka: Phenomena in arc welding with a multiple-wire electrode increasing energy efficiency:

    OpenAIRE

    Tušek, Janez

    2002-01-01

    Arc welding with a multiple-wire electrode, particularly with a twin-wire electrode, has lately found increasing application in practice. We know submerged-arc and gas-shielded arc welding processes with a twin-wire electrode and submerged arc welding with a multiple-wire (triple wire, quadruple wire) electrode. A unit for multiple-wire welding allows welding and surfacing. A principle of multiple-wire welding is that a single welding current source, a joint wire feed mechanism, and common re...

  18. Plasma diagnostics in gas metal arc welding by optical emission spectroscopy

    International Nuclear Information System (INIS)

    The plasma column in a metal inert gas welding process is investigated by optical emission spectroscopy and high-speed imaging. The concentration and repartition of iron vapours are measured and correlated with the plasma and electrode geometric configuration. Plasma temperatures and electron densities are also measured for each studied position in the plasma. The temperatures are calculated using two different methods, allowing validation of the local thermodynamic equilibrium state of the plasma. The results show a maximum temperature of 12 500 K in the upper part of the arc, away from the arc axis. The iron concentration reaches a maximum of 0.3% close to the anode and strongly decreases along both the vertical and radial directions. The plasma thermophysical properties, calculated from this plasma composition, are then discussed regarding the metal transfer mode.

  19. Plasma diagnostics in gas metal arc welding by optical emission spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Valensi, F; Pellerin, S; Zielinska, S [GREMI, Universite d' Orleans (Site de Bourges)/CNRS, BP 4043, 18028 Bourges cedex (France); Boutaghane, A [Universite des Sciences et de la Technologie Houari Boumediene, Alger (Algeria); Dzierzega, K [Marian Smoluchowski Institute of Physics, Jagellonian University, Krakow (Poland); Pellerin, N [CNRS, UPR3079 CEMHTI, 1D av. de la Recherche Scientifique, 45071 Orleans cedex 2 (France); Briand, F, E-mail: flavien.valensi@laplace.univ-tsle.f, E-mail: stephane.pellerin@univ-orleans.f, E-mail: aboutaghane@yahoo.f, E-mail: krzycho@netmail.if.uj.edu.p, E-mail: sylwia.zielinska@airliquide.co, E-mail: nadia.pellerin@univ-orleans.f, E-mail: francis.briand@airliquide.co [CTAS-Air Liquide Welding, Saint Ouen l' Aumone, 95315 Cergy-Pontoise cedex (France)

    2010-11-03

    The plasma column in a metal inert gas welding process is investigated by optical emission spectroscopy and high-speed imaging. The concentration and repartition of iron vapours are measured and correlated with the plasma and electrode geometric configuration. Plasma temperatures and electron densities are also measured for each studied position in the plasma. The temperatures are calculated using two different methods, allowing validation of the local thermodynamic equilibrium state of the plasma. The results show a maximum temperature of 12 500 K in the upper part of the arc, away from the arc axis. The iron concentration reaches a maximum of 0.3% close to the anode and strongly decreases along both the vertical and radial directions. The plasma thermophysical properties, calculated from this plasma composition, are then discussed regarding the metal transfer mode.

  20. 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

  1. Inclusions and Microstructure of Ce-Added Weld Metal Coarse Grain Heat-Affected Zone in Twin-Wire Submerged-Arc Welding

    Science.gov (United States)

    Yu, S. F.; Yan, N.; Chen, Y.

    2016-06-01

    In high heat-input multi-pass twin-wire submerged-arc welding, weld metal of previous pass will be affected by the heat input of subsequent one and form coarse-grained heat-affected zone (CGHAZ). This study focused on the effects of welding thermal cycle on the inclusions and microstructure of Ce-alloyed weld metal CGHAZ. According to the study of inclusions and microstructure of weld metal CGHAZ, it was found that the composition and type of the inclusions did not change under the effect of welding thermal cycle. Although the inclusions were coarsened slightly, the promoting ability to acicular ferrite (AF) was not deprived after thermal cycling. There are three types of AF in weld metal CGHAZ, which include oxy-sulfides of Ce inclusions-promoted AF, home-position-precipitated AF, and sympathetic AF. Results showed more than 80% of microstructure was AF, which greatly benefited the mechanical properties of weld metal CGHAZ, even though granular bainite and M-A constituents were generated.

  2. Corrosion evaluation of multi-pass welded nickel–aluminum bronze alloy in 3.5% sodium chloride solution: A restorative application of gas tungsten arc welding process

    International Nuclear Information System (INIS)

    Highlights: • Corrosion of GTA welded nickel–aluminum bronze (C95800) was studied. • Drastic microstructural changes occurred during the welding operations. • The β′ and α phases acts as anode and cathode, correspondingly, in weld region. • A few nanoamperes couple current was measured in ZRA test as galvanic corrosion. • Corrosion resistance of weld parts could not be weakened in marine environments. - Abstract: In this research, the corrosion behavior of a gas tungsten arc welded nickel–aluminum bronze (NAB) alloy is investigated by DC and AC electrochemical techniques in 3.5% sodium chloride solution. Regarding the electrochemical impedance spectroscopy and potentiodynamic results, uniform corrosion resistance of instantly immersed weld and base samples are almost analogous and increased (more in weld region) during the immersion times. Moreover, zero resistant ammeter results demonstrated that the few nanoampere galvanic currents are attributed to microstructural and morphological differences between these two regions. Therefore, the welding procedure could not deteriorate the general corrosion resistance of the restored damaged NAB parts operating in marine environments

  3. Relation between various chromium compounds and some other elements in fumes from manual metal arc stainless steel welding.

    OpenAIRE

    Matczak, W; Chmielnicka, J

    1993-01-01

    For the years 1987-1990 160 individual samples of manual metal arc stainless steel (MMA/SS) welding fumes from the breathing zone of welders in four industrial plants were collected. Concentrations of soluble and insoluble chromium (Cr) III and Cr VI compounds as well as of some other welding fume elements (Fe, Mn, Ni, F) were determined. Concentration of welding fumes in the breathing zone ranged from 0.2 to 23.4 mg/m3. Total Cr amounted to 0.005-0.991 mg/m3 (including 0.005-0.842 mg/m3 Cr V...

  4. SIMULATION AND EXPERIMENTATION OF THE ARC WELDING INVERTER USING THE SOFT SWITCHING TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    Chen Shujun; Wang Jun; Huang Pengfei; L(u) Yaohui; Yin Shuyan

    2004-01-01

    The FB-ZVZCS-PWM converter is realized by the way of subjoining block-capacitor into the FB-ZVS-PWM converter.At the freewheeling interval, the primary current is attenuated fast to zero and maintained.And then, power device of the static leg becomes a zero-current-switch (ZCS), power device of the shifted leg becomes a zero-voltage-switch(ZVS).Thus, on one hand IGBT (Insulated gate bipolar transistor) with tail current can be easily used in full-bridge soft-switching converter; on the other hand additional circuiting energy is greatly reduced.At the same time, less duty cycle loss, lower secondary parasitic resonance, wider soft-switching load range can be achieved.Based on the existing component models in the Pspice software package, a combined model of IGBT is established, in which a non-linear capacitor is introduced to replace the parasitic capacitor.Using this model, computerized simulation is conducted for the FB-ZVZCS-PWM soft-switching converter, the switching and energy-transferring characteristics of the power device are analyzed.Finally, based on the achievement above, a 10 kW arc welding inverter with FB-ZVZCS-PWM converter is deve- loped.The simulation results are testified by experiments.It is proved that by adopting appropriate models, computerized simulation is an effective and useful tool for the development of the arc welding inverter.

  5. Structure and properties of welded joints under laser and arc welding of Zr-2.5%Nb alloy

    International Nuclear Information System (INIS)

    Laser welding was used for improving plasticity of welded joints of Zr-2.5%Nb compositions. It is noted that laser welding of Zr-2.5%Nb alloy at 100-120 m/h rate allows to produce joints featuring high quality, high strength and plasticity of welds whose bend angel equals 160-180 deg. Corrosion resistance of joints in sulphuric, nitric and acetic acids is at the level of basic metal resistance. Decrease of weld width, heat contribution and chemical inhomogeneity of weld metal and HAZ under laser welding conditions reduces the tendency of weld joints to intercrystal corrosion in a 70% solution of sulphuric acid

  6. Interaction between laser-induced plasma/vapor and arc plasma during fiber laser-MIG hybrid welding

    International Nuclear Information System (INIS)

    Hybrid plasma is an important physical phenomenon in fiber laser-MIG hybrid welding. It greatly affects the stability of the process, the quality of the weld, and the efficiency of energy coupling. In this paper, clear and direct proofs of these characteristics are presented through high-speed video images. Spectroscopic analysis is used to describe the characterization of hybrid plasma. The hybrid plasma forms a curved channel between the welding wire and the keyhole during the fiber laser-MIG hybrid welding process. The curved channel is composed of two parts. The laser-induced plasma/vapor expands due to the combined effect of the laser and the MIG arc, forming an ionization duct, which is one part of the curved channel. The resistance of the duct is smaller than that of other locations because of the rise in electrical conductivity. Consequently, the electrical arc is guided through the duct to the surface of the material, which is the other part of the curved channel. The spectral intensities of metal elements in laser-MIG hybrid welding are much stronger than those in MIGonly welding, whereas the spectral intensities of shielding gas element in laser-MIG hybrid welding are much weaker

  7. Micro–macro-characterisation and modelling of mechanical properties of gas metal arc welded (GMAW) DP600 steel

    International Nuclear Information System (INIS)

    Dual-phase (DP) steels show combined high strength and adequate formability. However, during welding, their microstructural feature of dispersion of hard martensite islands in the soft ferrite matrix is lost and the properties deteriorate. The current research aims to study the mechanical properties of the welded joint, taking into account the effect of features of all regions, such as microstructure, chemical composition and the area fraction, on the macroscopic mechanical properties of the welded joint. Hot rolled DP 600 steel was gas metal arc welded (GMAW) and tensile specimens were made with a welded joint. In the heat-affected zone (HAZ), the microstructure varied from bainite to coarse grained ferrite and tempered martensite. Chemical composition of every quantified region in the welded specimen was also identified using electron probe microanalysis (EPMA). Macromechanical FE modelling was employed to simulate the mechanical properties of the welded tensile specimen. 2D representative volume elements (RVE) for different parts of the welded region were constructed from real microstructure. 2D simulated flow curves were corrected to 3Ds using a developed correlation factor. Finally, the tensile test of welded material with inhomogeneous morphology was simulated and good agreement between experimental and predicted flow curve was achieved

  8. Effect of Gas Tungsten Arc Welding Parameters on Hydrogen-Assisted Cracking of Type 321 Stainless Steel

    Science.gov (United States)

    Rozenak, Paul; Unigovski, Yaakov; Shneck, Roni

    2016-05-01

    The susceptibility of AISI type 321 stainless steel welded by the gas tungsten arc welding (GTAW) process to hydrogen-assisted cracking (HAC) was studied in a tensile test combined with in situ cathodic charging. Specimen charging causes a decrease in ductility of both the as-received and welded specimens. The mechanical properties of welds depend on welding parameters. For example, the ultimate tensile strength and ductility increase with growing shielding gas (argon) rate. More severe decrease in the ductility was obtained after post-weld heat treatment (PWHT). In welded steels, in addition to discontinuous grain boundary carbides (M23C6) and dense distribution of metal carbides MC ((Ti, Nb)C) precipitated in the matrix, the appearance of delta-ferrite phase was observed. The fracture of sensitized specimens was predominantly intergranular, whereas the as-welded specimens exhibited mainly transgranular regions. High-dislocation density regions and stacking faults were found in delta-ferrite formed after welding. Besides, thin stacking fault plates and epsilon-martensite were found in the austenitic matrix after the cathodic charging.

  9. Laser-Arc Hybrid Welding of Dissimilar Titanium Alloy and Stainless Steel Using Copper Wire

    Science.gov (United States)

    Gao, Ming; Chen, Cong; Wang, Lei; Wang, Zemin; Zeng, Xiaoyan

    2015-05-01

    Laser-arc hybrid welding with Cu3Si filler wire was employed to join dissimilar Ti6Al4V titanium alloy and AISI316 stainless steel (316SS). The effects of welding parameters on bead shape, microstructure, mechanical properties, and fracture behavior were investigated in detail. The results show that cross-weld tensile strength of the joints is up to 212 MPa. In the joint, obvious nonuniformity of the microstructure is found in the fusion zone (FZ) and at the interfaces from the top to the bottom, which could be improved by increasing heat input. For the homogeneous joint, the FZ is characterized by Fe67- x Si x Ti33 dendrites spreading on α-Cu matrix, and the two interfaces of 316SS/FZ and FZ/Ti6Al4V are characterized by a bamboo-like 316SS layer and a CuTi2 layer, respectively. All the tensile samples fractured in the hardest CuTi2 layer at Ti6Al4V side of the joints. The fracture surface is characterized by river pattern revealing brittle cleavage fracture. The bead formation mechanisms were discussed according to the melt flow and the thermodynamic calculation.

  10. Twin-wire Submerged Arc Welding Process of a High-strength Low-alloy Steel

    Institute of Scientific and Technical Information of China (English)

    YANG Xiuzhi; XU Qinghua; YIN Niandong; XIAO Xinhua

    2011-01-01

    The measurement of thermal cycle curves of a high-strength low-alloy steel (HSLA)subjected twin-wire submerged arc welding (SAW) was introduced. The thermal simulation test was performed by using the obtained curves. The impact toughness at -50 ℃ temperature of the simulated samples was also tested. OM, SEM and TEM of the heat-affected zone (HAZ) of some simulation specimens were investigated. The results showed that the HSLA endured the twin-wire welding thermal cycle, generally, the low-temperature toughness values of each part of HAZ was lower than that of the parent materials, and the microstructure of coarse-grained zone(CGHAZ) mainly made up of granular bainite is the reason of the toughness serious deterioration. Coarse grain, grain boundary carbide extract and M-A island with large size and irregular polygon, along the grain boundary distribution, are the reasons for the toughness deterioration of CGHAZ. The research also showed that selected parameters of twin-wire SAW can meet the requirements to weld the test steel.

  11. Development of an encapsulation method using plasma arc welding to produce iodine-125 seeds for brachytherapy

    International Nuclear Information System (INIS)

    The prostate cancer, which is the second cause of death by cancer in men, overcome only by lung cancer is public health problem in Brazil. Brachytherapy is among the possible available treatments for prostate cancer, in which small seeds containing Iodine-125 radioisotope are implanted into the prostate gland. The seed consists of a titanium sealed capsule with 0.8 mm external diameter and 4.5 mm length, containing a central silver wire with adsorbed Iodine-125. The Plasma Arc Welding (PAW) is one of the viable techniques for sealing process. The equipment used in this technique is less costly than in other processes, such as, Laser Beam Welding (LBW). The main purpose of this work was the development of an encapsulation method using PAW. The development of this work has presented the following phases: cutting and cleaning titanium tube, determination of the welding parameters, development of a titanium tube holding device for PAW, sealed sources validation according to ISO 2919 - Sealed Radioactive Sources - General Requirements and Classification, and metallographic assays. The developed procedure to seal Iodine-125 seeds using PAW has shown high efficiency, satisfying all the established requirements of ISO 2919. The results obtained in this work will give the possibility to establish a routine production process according to the orientations presented in resolution RDC 17 - Good Manufacturing Practices to Medical Products defined by the ANVISA - National Agency of Sanitary Surveillance. (author)

  12. Development of an encapsulation method using plasma arc welding to produce iodine-125 seeds for brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Feher, Anselmo; Calvo, Wilson A.P.; Rostelato, Maria E.C.M.; Zeituni, Carlos A.; Somessari, Samir L.; Costa, Osvaldo L.; Moura, Joao A.; Moura, Eduardo S.; Souza, Carla D.; Rela, Paulo R., E-mail: afeher@ipen.b, E-mail: wapcalvo@ipen.b, E-mail: elisaros@ipen.b, E-mail: somessar@ipen.b, E-mail: olcosta@ipen.b, E-mail: esmoura@ipen.b, E-mail: cdsouza@ipen.b, E-mail: prela@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

    2011-07-01

    The prostate cancer, which is the second cause of death by cancer in men, overcome only by lung cancer is public health problem in Brazil. Brachytherapy is among the possible available treatments for prostate cancer, in which small seeds containing Iodine-125 radioisotope are implanted into the prostate gland. The seed consists of a titanium sealed capsule with 0.8 mm external diameter and 4.5 mm length, containing a central silver wire with adsorbed Iodine-125. The Plasma Arc Welding (PAW) is one of the viable techniques for sealing process. The equipment used in this technique is less costly than in other processes, such as, Laser Beam Welding (LBW). The main purpose of this work was the development of an encapsulation method using PAW. The development of this work has presented the following phases: cutting and cleaning titanium tube, determination of the welding parameters, development of a titanium tube holding device for PAW, sealed sources validation according to ISO 2919 - Sealed Radioactive Sources - General Requirements and Classification, and metallographic assays. The developed procedure to seal Iodine-125 seeds using PAW has shown high efficiency, satisfying all the established requirements of ISO 2919. The results obtained in this work will give the possibility to establish a routine production process according to the orientations presented in resolution RDC 17 - Good Manufacturing Practices to Medical Products defined by the ANVISA - National Agency of Sanitary Surveillance. (author)

  13. Gas tungsten arc welding assisted hybrid friction stir welding of dissimilar materials Al6061-T6 aluminum alloy and STS304 stainless steel

    International Nuclear Information System (INIS)

    Highlights: ► GTAW assisted hybrid friction stir welding (HFSW) has been carried out for dissimilar butt joint. ► Mechanical strength of dissimilar butt joint by HFSW and FSW has been investigated and compared. ► Microstructure of dissimilar butt joint by HFSW and FSW has been investigated and compared. -- Abstract: The aim of this research is to evaluate the potential for using the gas tungsten arc welding (GTAW) assisted hybrid friction stir welding (HFSW) process to join a stainless steel alloy (STS304) to an aluminum alloy (Al6061) in order to improve the weld strength. The difference in mechanical and microstructural characteristics of dissimilar joint by friction stir welding (FSW) and HFSW has been investigated and compared. Transverse tensile strength of approximately 93% of the aluminum alloy (Al6061) base metal tensile strength is obtained with HFSW, which is higher than the tensile strength of FSW welds. This may be due to the enhanced material plastic flow and partial annealing effect in dissimilar materials due to preheating of stainless steel surface by GTAW, resulting in significantly increased elongation of welds. The results indicate that HFSW that integrates GTAW preheating to FSW is advantageous in joining dissimilar combinations compared to conventional FSW.

  14. The effect of varying the MnO content of the flux used for the submerged arc welding of Navy HY-100 steel

    OpenAIRE

    Clark, Allen L.

    1995-01-01

    Weld metal strength and toughness are determined by its microstructure, which is in turn determined by the concentration of various alloying elements and impurities as well as the welding thermal cycle. This study investigated the effects of systematically varying the manganese oxide content in the flux used for HY-l00 submerged arc welds. A trial addition of cerium oxide was also performed. Specimens were compared using mechanical properties, weld metal chemistry, inclusion chemistry, and mi...

  15. Modelling of binary alloy (Al–Mg) anode evaporation in arc welding

    International Nuclear Information System (INIS)

    A simple analytical model of binary alloy anode evaporation in gas–tungsten arc and gas–metal arc welding is proposed. The model comprises the model of evaporation in convective and diffusive regimes, model of anode processes and allows one to calculate basic physical properties of multicomponent arc plasma near the anode surface as functions of the anode surface temperature, anode chemical composition, electron temperature and electric current density at the anode surface. Evaporation of binary Al–Mg alloys with different magnesium mass fraction into argon plasma is considered on the basis of the proposed model. The dependences of the alloy boiling temperature on the magnesium mass fraction and electron temperature are presented. Several physical parameters, which are important from the technological point of view (magnesium mass flux, heat loss due to evaporation, anode potential drop, anode heat flux), are calculated for a wide range of anode surface temperature and different values of the magnesium mass fraction. In addition, the influence of heat loss due to evaporation on the total heat flux coming to the anode surface is demonstrated. (paper)

  16. Optimizing pulsed current gas tungsten arc welding parameters of AA6061 aluminium alloy using Hooke and Jeeves algorithm

    Institute of Scientific and Technical Information of China (English)

    S. BABU; T. SENTHIL KUMAR; V. BALASUBRAMANIAN

    2008-01-01

    Though the preferred welding process to weld aluminium alloy is frequently constant current gas tungsten arc welding (CCGTAW), it resulted in grain coarsening at the fusion zone and heat affected zone(HAZ). Hence, pulsed current gas tungsten arc welding(PCGTAW) was performed, to yield finer fusion zone grains, which leads to higher strength of AA6061 (Al-Mg-Si) aluminium alloy joints. In order to determine the most influential control factors which will yield minimum fusion zone grain size and maximum tensile strength of the joints, the traditional Hooke and Jeeves pattern search method was used. The experiments were carried out based on central composite design with 31 runs and an algorithm was developed to optimize the fusion zone grain size and the tensile strength of pulsed current gas tungsten arc welded AA6061 aluminium aUoy joints. The results indicate that the peak current (Ip) and base current (IB) are the most significant parameters, to decide the fusion zone grain size and the tensile strength of the AA6061 aluminum alloy joints.

  17. Dynamic behaviour of an electric arc gas discharge

    International Nuclear Information System (INIS)

    The time-dependent energy and circuit equations are solved numerically to obtain temperature profiles, current-voltage characteristics and electric field strength vs axial temperature diagrams in the asymptotic region of a wall-stabilized electric arc operated in nitrogen. Dynamic current-voltage characteristics and transient phenomena of steady state formation during the spark ignition phase are studied. The arc time-constant for free decay is computed and compared with approximate analytical results. It is found that for fixed initial conditions, the arc response to the variable applied voltage is several times longer than the arc time-constant for free decay. (author) 4 figs., 11 refs

  18. Gas tungsten arc welding of ZrB2–SiC based ultra high temperature ceramic composites

    Directory of Open Access Journals (Sweden)

    R.V. Krishnarao

    2015-09-01

    Full Text Available The difficulty in fabricating the large size or complex shape limits the application of ZrB2–SiC composites. Joining them by fusion welding without or with preheating, controlled cooling under protective gas shield leads to thermal shock failure or porosity at the weld interface. In the present work, a filler material of (ZrB2–SiC–B4C–YAG composite with oxidation resistance and thermal shock resistance was produced in the form of welding wire. Using the filler, gas tungsten arc welding (GTAW was performed without employing preheating, post controlled cooling and extraneous protective gas shield to join hot pressed ZrB2–SiC (ZS, and pressureless sintered ZrB2–SiC–B4C–YAG (ZSBY composites to themselves. The fusion welding resulted in cracking and non-uniform joining without any filler material. The weld interfaces of the composites were very clean and coherent. The Vickers micro-hardness across the weld interface was found to increase due to the increase in the volume % of both SiC and B4C in the filler material. The shear strength of the weld was about 50% of the flextural strength of the parent composite.

  19. Effect of Ti on hot cracking and mechanical performance in the gas tungsten arc welds of copper thick plates

    International Nuclear Information System (INIS)

    Highlights: ► The new welding material – ERCuTi fillers are designed special for copper welding. ► The observation is the first confirmation that the eutectic is the cracking source. ► The mechanical performance of the welds in BTR is improved by adding Ti in fillers. ► The amount of Ti in fillers has the influences on hot cracking susceptibility. -- Abstract: The new welding material – ERCuTi alloys filler metals were developed for gas tungsten arc welding (GTAW) of copper. The cracking susceptibility of the welds with ERCuTi and ERCu separately in GTAW of 10 mm copper thick plates was investigated. The formation causes of hot cracking was researched by using ERCu and the suppression mechanism of hot cracking when using ERCuTi alloy filler was proposed. It has been found that, when element Ti is added into the welding pool, the Ti will combine with O preferentially rather than Cu to generate TiO2, which process can suppress the formation of Cu2O. The hot cracking force and the hot ductility of the welds in brittle temperature range (BTR) could be improved effectively by adding Ti in filler metal compared with that of the welds without Ti. But the degree of addition of Ti (2–4 wt%) is critical when the susceptibility of cracking is to be suppressed. If the level is allowed to exceed 4 wt%, more low-melting point eutectics (β-TiCu4 and TiCu2) will be formed in the welds, and cracking susceptibility will be increased again. Results of mechanical properties tests show that although adding Ti increases the hardness and strength of the weld compared to the base metal, the impact ductility and the plastic properties are not decreased significantly.

  20. Magneto-plasma-dynamic arc thruster

    Science.gov (United States)

    Burkhart, J. A. (Inventor)

    1973-01-01

    The performance of a magnetoplasmadynamic arc thruster, in the 600 to 2,100 seconds specific impulse range, was improved by locating its cathode in the exhaust beam downstream of the anode and main propellant injection point.

  1. 3D reconstruction of worn parts for flexible remanufacture based on robotic arc welding

    Institute of Scientific and Technical Information of China (English)

    Yin Ziqiang; Zhang Guangjun; Gao Hongming; Wu Lin

    2010-01-01

    3D reconstruction of worn parts is the foundation for remanufacturing system based on robotic arc welding,because it can provide 3D geometric information for robot task plan.In this investigation,a nocwl 3D reconstruction system based on linear structured light vision sensing is developed,This system hardware consists of a MTC368-CB CCD camera,a MLH-645laser projector and a DH-CG300 image grabbing card.This system software is developed to control the image data capture.In order to reconstruct the 3D geometric information from the captured image,a two steps rapid calibration algorithm is proposed.The 3D reconstruction experiment shows a satisfactory result.

  2. Effects of neutron irradiation on fracture toughness of A533-B Class 1 plate and four submerged-arc welds

    International Nuclear Information System (INIS)

    An irradiation program was carried out with four submerged-arc welds and one plate of A533-B Class 1 pressure vessel steel. The welds were made by commercial vendors using current welding practice and contained relatively low copper levels. The target fluence was 2 X 1023 neutrons (n)/m2 (E > 1 MeV). The program was administered by Oak Ridge National Laboratory (ORNL) through the Heavy Section Steel Technology Program Office, and the testing was shared by ORNL and Materials Engineering Associates, Inc. (MEA). The results of the test program indicated that the welds had generally very good properties (tension, Charpy V-notch, and fracture toughness) prior to irradiation and with the exception of tearing modulus all five materials were relatively insensitive to irradiation on the upper shelf. The data further indicated that shifts of the transition region to higher temperature with irradiation is directly related to the copper and nickel content

  3. #A #study of the cold cracking in multi-pass weld metal made by a submerged-arc welding process

    OpenAIRE

    Praunseis, Zdravko; Toyoda, Masao

    2012-01-01

    One of the weldability problems with HSLA steels is the cold cracking phenomenon. In this research special attention has been paid to cold cracks appearing in the multi pass weld metal. Cold cracking is prevented by the preheating of steel prior to welding in order to achieve a beneficial microstructure, and by the drying of the welding flux and the post heating of a welded joint for the expulsion of dissolved hydrogen. An accurate determination of the preheating temperature is necessary beca...

  4. Numerical modeling of a hybrid arc / laser welding process in a level set framework : application to multipass welding of high thickness steel sheets

    OpenAIRE

    Desmaison, Olivier

    2013-01-01

    Hybrid arc / laser welding represents the solution for high thickness steel sheets assembly. The laser heat source added to the MIG torch improves the process productivity while respecting quality standards. Nevertheless, the phenomenology of the process remains complex and not totally understood. This is the thrust for the development of numerical simulation. The present study has been carried out as part of the "SISHYFE" Material and Process ANR project.For that purpose, a new non stationar...

  5. Evolution of weld metal microstructure in shielded metal arc welding of X70 HSLA steel with cellulosic electrodes: A case study

    Energy Technology Data Exchange (ETDEWEB)

    Ghomashchi, Reza, E-mail: reza.ghomashchi@adelaide.edu.au; Costin, Walter; Kurji, Rahim

    2015-09-15

    The microstructure of weld joint in X70 line pipe steel resulted from shielded metal arc welding with E6010 cellulosic electrodes is characterized using optical and electron microscopy. A range of ferritic morphologies have been identified ranging from polygonal inter- and intra-prior austenite grains allotriomorphic, idiomorphic ferrites to Widmanstätten, acicular and bainitic ferrites. Electron Backscatter Diffraction (EBSD) analysis using Image Quality (IQ) and Inverse Pole Figure (IPF) maps through superimposition of IQ and IPF maps and measurement of percentages of high and low angle grain boundaries was identified to assist in differentiation of acicular ferrite from Widmanstätten and bainitic ferrite morphologies. In addition two types of pearlitic structures were identified. There was no martensite detected in this weld structure. The morphology, size and chemistry of non-metallic inclusions are also discussed briefly. - Highlights: • Application of EBSD reveals orientation relationships in a range of phases for shielded metal arc welding of HSLA steel. • Nucleation sites of various ferrite morphologies identified • Formation of upper and lower bainite and their morphologies.

  6. Multi-objective optimization of weld geometry in hybrid fiber laser-arc butt welding using Kriging model and NSGA-II

    Science.gov (United States)

    Gao, Zhongmei; Shao, Xinyu; Jiang, Ping; Wang, Chunming; Zhou, Qi; Cao, Longchao; Wang, Yilin

    2016-06-01

    An integrated multi-objective optimization approach combining Kriging model and non-dominated sorting genetic algorithm-II (NSGA-II) is proposed to predict and optimize weld geometry in hybrid fiber laser-arc welding on 316L stainless steel in this paper. A four-factor, five-level experiment using Taguchi L25 orthogonal array is conducted considering laser power ( P), welding current ( I), distance between laser and arc ( D) and traveling speed ( V). Kriging models are adopted to approximate the relationship between process parameters and weld geometry, namely depth of penetration (DP), bead width (BW) and bead reinforcement (BR). NSGA-II is used for multi-objective optimization taking the constructed Kriging models as objective functions and generates a set of optimal solutions with pareto-optimal front for outputs. Meanwhile, the main effects and the first-order interactions between process parameters are analyzed. Microstructure is also discussed. Verification experiments demonstrate that the optimum values obtained by the proposed integrated Kriging model and NSGA-II approach are in good agreement with experimental results.

  7. Evolution of weld metal microstructure in shielded metal arc welding of X70 HSLA steel with cellulosic electrodes: A case study

    International Nuclear Information System (INIS)

    The microstructure of weld joint in X70 line pipe steel resulted from shielded metal arc welding with E6010 cellulosic electrodes is characterized using optical and electron microscopy. A range of ferritic morphologies have been identified ranging from polygonal inter- and intra-prior austenite grains allotriomorphic, idiomorphic ferrites to Widmanstätten, acicular and bainitic ferrites. Electron Backscatter Diffraction (EBSD) analysis using Image Quality (IQ) and Inverse Pole Figure (IPF) maps through superimposition of IQ and IPF maps and measurement of percentages of high and low angle grain boundaries was identified to assist in differentiation of acicular ferrite from Widmanstätten and bainitic ferrite morphologies. In addition two types of pearlitic structures were identified. There was no martensite detected in this weld structure. The morphology, size and chemistry of non-metallic inclusions are also discussed briefly. - Highlights: • Application of EBSD reveals orientation relationships in a range of phases for shielded metal arc welding of HSLA steel. • Nucleation sites of various ferrite morphologies identified • Formation of upper and lower bainite and their morphologies

  8. A dynamic model of droplet formation in GMA welding

    International Nuclear Information System (INIS)

    A comparative analysis of different approaches is carried out, which mathematically describes the metal droplet formation process in an electrode during gas metal arc (GMA) welding. It was shown that a hydrostatical model of the droplet's free surface could not correctly describe the formation and transfer of electrode metal droplets. The complete hydrodynamic model, which uses the whole system of Navier–Stokes equations, requires significant computer resources for numerical realization. This limits its application to small computational experiments. As an alternative for this model, the approximate hydrodynamic model adapted to GMA welding conditions is considered. It is shown that this model allows the prediction of droplet geometry right up to its detachment. The influence of the welding current and magnetic pressure on the droplet size and detachment frequency is studied. (paper)

  9. Influence of Tacking Sequence on Residual Stress and Distortion of Single Sided Fillet Submerged Arc Welded Joint

    Institute of Scientific and Technical Information of China (English)

    Arpan Kumar Mondal; Pankaj Biswas; Swarup Bag

    2015-01-01

    Submerged arc welding (SAW) is advantageous for joining high thickness materials in large structure due to high material deposition rate. The non-uniform heating and cooling generates the thermal stresses and subsequently the residual stresses and distortion. The longitudinal and transverse residual stresses and angular distortion are generally measured in large panel structure of submerged arc welded fillet joints. Hence, the objective of this present work is to quantify the amount of residual stress and distortion in and around the weld joint due to positioning of stiffeners tack. The tacking sequence influences the level of residual stress and proper controlling of tacking sequences is required to minimize the stress. In present study, an elasto-plastic material behavior is considered to develop the thermo mechanical model which predicts the residual stress and angular distortion with varying tacking sequences. The simulated result reveals that the tacking sequence heavily influences the residual stress and deformation pattern of the single sided fillet joint. The finite element based numerical model is calibrated by comparing the experimental data from published literature. Henceforth, the angular distortions are measured from an in-house developed experimental set-up. A fair agreement between the predicted and experimental results indicates the robustness of the developed numerical model. However, the most significant conclusion from present study states that tack weld position should be placed opposite to the fillet weld side to minimize the residual stress.

  10. Characteristics and performance of the variable polarity plasma arc welding process used in the Space Shuttle external tank

    Science.gov (United States)

    Hung, R. J.; Lee, C. C.; Liu, J. W.

    1990-01-01

    Significant advantages of the Variable Polarity Plasma Arc (VPPA) Welding Process include faster welding, fewer repairs, less joint preparation, reduced weldment distortion, and absence of porosity. Flow profiles and power distribution of argon plasma gas as a working fluid to produce plasma arc jet in the VPPA welding process was analyzed. Major loss of heat transfer for flow through the nozzle is convective heat transfer; for the plasma jet flow between the outlet of the nozzle and workpiece is radiative heat transfer; and for the flow through the keyhole of the workpiece is convective heat transfer. The majority of the power absorbed by the keyhole of the workpiece is used for melting the solid metal workpiece into a molten metallic puddle. The crown and root widths and the crown and root heights can be predicted. An algorithm for promoting automatic control of flow parameters and the dimensions of the final product of the welding specification to be used for the VPPA Welding System operated at MSFC are provided.

  11. Influence of tacking sequence on residual stress and distortion of single sided fillet submerged arc welded joint

    Science.gov (United States)

    Mondal, Arpan Kumar; Biswas, Pankaj; Bag, Swarup

    2015-07-01

    Submerged arc welding (SAW) is advantageous for joining high thickness materials in large structure due to high material deposition rate. The non-uniform heating and cooling generates the thermal stresses and subsequently the residual stresses and distortion. The longitudinal and transverse residual stresses and angular distortion are generally measured in large panel structure of submerged arc welded fillet joints. Hence, the objective of this present work is to quantify the amount of residual stress and distortion in and around the weld joint due to positioning of stiffeners tack. The tacking sequence influences the level of residual stress and proper controlling of tacking sequences is required to minimize the stress. In present study, an elasto-plastic material behavior is considered to develop the thermo mechanical model which predicts the residual stress and angular distortion with varying tacking sequences. The simulated result reveals that the tacking sequence heavily influences the residual stress and deformation pattern of the single sided fillet joint. The finite element based numerical model is calibrated by comparing the experimental data from published literature. Henceforth, the angular distortions are measured from an in-house developed experimental set-up. A fair agreement between the predicted and experimental results indicates the robustness of the developed numerical model. However, the most significant conclusion from present study states that tack weld position should be placed opposite to the fillet weld side to minimize the residual stress.

  12. Study and development of solid fluxes for gas tungsten arc welding applied to titanium and its alloys and stainless steels

    International Nuclear Information System (INIS)

    Gas Tungsten Arc Welding uses an electric arc between the refractory tungsten electrode and the plates to be welded under an argon shielding gas. As a result, the joint quality is excellent, no pollution nor defects are to be feared, consequently this process is used in nuclear, aeronautic, chemical and food industries. Despite of this good qualities, GTAW is limited because of, on the one side, a poor penetrating weld pool and, on the other side, a week productivity rate. Indeed, up to 3 mm thick plates, machining and filler metal is needed. Multiple runs increase the defect's risks, the manufactory time and increase the deformations and the heat affected zone. The goal of this study is to break through this limits without any device investment. Active GTA welding (or ATIG) is a new technique with GTA device and an activating flux to be spread on the upper plate before welding. The arc, by plasma electrochemical equilibrium modifications, and the pool with the inner connective flows inversion, allow 7 mm thick joints in one run without edges machining or filler metal for both stainless steel and titanium alloys. This manuscript describes the development of these fluxes, highlights the several phenomena and presents the possibilities of this new process. This work, in collaboration with B.S.L. industries, leads to two flux formulations (stainless steel and titanium alloys) now in a commercial phase with CASTOLIN S.A. Moreover, B.S.L.industries produces a pressure device (nitrate column) with the ATIG process using more than 2800 ATIG welds. (author)

  13. Determining chaotic invariant properties of short-circuiting gas metal arc welding from an observed time series

    Institute of Scientific and Technical Information of China (English)

    Xiang Yuanpeng; Cao Biao; Zeng Min; Huang Shisheng; Shao Lanjuan

    2008-01-01

    The experimental time series of welding current produced by carbon dioxide gas metal arc welding with shortcircuiting transfer were recorded and subsequently evaluated. Based on phase space reconstruction, the correlation dimensions and Kolmogorov entropies of the corresponding system have been numerically calculated using the Grassberger-Procaccia algorithm at different time delays. It was found out that the time delay has little effect on the estimation of correlation dimension; conversely,it plays a key role in producing precise results on the estimation of Kolmogorov entropy.

  14. Analisa Ketangguhan dan Struktur Mikro pada Daerah Las dan HAZ Hasil Pengelasan Sumerged Arc Welding pada Baja SM 490

    Directory of Open Access Journals (Sweden)

    Yusa Asra Yuli Wardana

    2006-01-01

    Full Text Available Submerged Arc Welding (SAW is one of method for welding process which used for the extensions of heavy construction, for example bridge construction. Broadness usage of SAW caused by welding process can be done automatically and have high reliability. Microstructure and toughness properties of weld metal were influenced by many factors such as chemical composition, heat input, filler, fluks, etc. This research aim to study influence of heat input. Welding Process was carried out using SAW with the material is SM 490, filler type used was EH 14 and the heat input were varied at 2,1 kJ/mm, 3,16 kJ/mm and 4,3 kJ/mm. The Results of this research show that an increase on heat input leads to coarsening the microstructure on the weld metal. A maximum percentage of Acicular Ferrite and hence the highest impact toughness were achieved at weld metal with heat input 2,1 kJ/mm where it's 50 joule with transition temperature -10 oC. The highest toughness with transition temperature 20 oC were obtained at heat input 3,16 kJ/mm where toughness was 117 joule. Abstract in Bahasa Indonesia : Pengelasan dengan menggunakan metode Sumerged Arc Welding (SAW adalah pengelasan yang banyak digunakan untuk penyambungan konstruksi berat, misalnya jembatan, perpipaan den bangunan. Luasnya penggunaan metode ini dikarenakan dapat dilakukan secara otomatis dan memiliki keandalan yang tinggi. Struktur mikro dan ketangguhan las dipengaruhi oleh banyak faktor seperti komposisi kimia logam las, input panas, filler, fluks dan lain-lain. Penelitian ini bertujuan untuk menganalisa struktur mikro dan ketangguhan hasil pengelasan SAW pada bahan baja karbon rendah. Percobaan dilakukan menggunakan bahan baja SM 490 dan filler jenis EH 14 sedangkan input panas yang digunakan adalah 2,1 kJ/mm, 3,16 kJ/mm, dan 4,3 kJ/mm. Hasil penelitian menunjukkan terjadinya pembesaran ukuran butir logam induk untuk setiap penaikan input panas. Pada heat input 2,1 kJ/mm menunjukkan jumlah Ferit Accicular

  15. Microstructure and abrasive wear properties of M(Cr,Fe)7C3 carbides reinforced high-chromium carbon coating produced by gas tungsten arc welding (GTAW) process

    OpenAIRE

    Buytoz, Soner; M.Mustafa YILDIRIM

    2010-01-01

    In the present study, high-chromium ferrochromium carbon hypereutectic alloy powder was coated on AISI 4340 steel by the gas tungsten arc welding (GTAW) process. The coating layers were analyzed by optical microscopy, X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), X-ray energy-dispersive spectroscopy (EDS). Depending on the gas tungsten arc welding pa-rameters, either hypoeutectic or hypereutectic microstructures were produced. Wear tests of the coatings were c...

  16. The Effect of Constant and Pulsed Current Gas Tungsten Arc Welding on Joint Properties of 2205 Duplex Stainless Steel to 316L Austenitic Stainless Steel

    Science.gov (United States)

    Neissi, R.; Shamanian, M.; Hajihashemi, M.

    2016-05-01

    In this study, dissimilar 316L austenitic stainless steel/2205 duplex stainless steel (DSS) joints were fabricated by constant and pulsed current gas tungsten arc welding process using ER2209 DSS as a filler metal. Microstructures and joint properties were characterized using optical and electron scanning microscopy, tensile, Charpy V-notch impact and micro-hardness tests, and cyclic polarization measurements. Microstructural observations confirmed the presence of chromium nitride and delta ferrite in the heat-affected zone of DSS and 316L, respectively. In addition, there was some deviation in the austenite/ferrite ratio of the surface welding pass in comparison to the root welding pass. Besides having lower pitting potential, welded joints produced by constant current gas tungsten arc welding process, consisted of some brittle sigma phase precipitates, which resulted in some impact energy reduction. The tensile tests showed high tensile strength for the weld joints in which all the specimens were broken in 316L base metal.

  17. The Effect of Constant and Pulsed Current Gas Tungsten Arc Welding on Joint Properties of 2205 Duplex Stainless Steel to 316L Austenitic Stainless Steel

    Science.gov (United States)

    Neissi, R.; Shamanian, M.; Hajihashemi, M.

    2016-04-01

    In this study, dissimilar 316L austenitic stainless steel/2205 duplex stainless steel (DSS) joints were fabricated by constant and pulsed current gas tungsten arc welding process using ER2209 DSS as a filler metal. Microstructures and joint properties were characterized using optical and electron scanning microscopy, tensile, Charpy V-notch impact and micro-hardness tests, and cyclic polarization measurements. Microstructural observations confirmed the presence of chromium nitride and delta ferrite in the heat-affected zone of DSS and 316L, respectively. In addition, there was some deviation in the austenite/ferrite ratio of the surface welding pass in comparison to the root welding pass. Besides having lower pitting potential, welded joints produced by constant current gas tungsten arc welding process, consisted of some brittle sigma phase precipitates, which resulted in some impact energy reduction. The tensile tests showed high tensile strength for the weld joints in which all the specimens were broken in 316L base metal.

  18. Tensile properties and strain-hardening behavior of double-sided arc welded and friction stir welded AZ31B magnesium alloy

    International Nuclear Information System (INIS)

    Microstructures, tensile properties and work hardening behavior of double-sided arc welded (DSAWed) and friction stir welded (FSWed) AZ31B-H24 magnesium alloy sheet were studied at different strain rates. While the yield strength was higher, both the ultimate tensile strength and ductility were lower in the FSWed samples than in the DSAWed samples due to welding defects present at the bottom surface in the FSWed samples. Strain-hardening exponents were evaluated using the Hollomon relationship, the Ludwik equation and a modified equation. After welding, the strain-hardening exponents were nearly twice that of the base metal. The DSAWed samples exhibited stronger strain-hardening capacity due to the larger grain size coupled with the divorced eutectic structure containing β-Mg17Al12 particles in the fusion zone, compared to the FSWed samples and base metal. Kocks-Mecking type plots were used to show strain-hardening stages. Stage III hardening occurred after yielding in both the base metal and the welded samples. At lower strains a higher strain-hardening rate was observed in the base metal, but it decreased rapidly with increasing net flow stress. At higher strains the strain-hardening rate of the welded samples became higher, because the recrystallized grains in the FSWed and the larger re-solidified grains coupled with β particles in the DSAWed provided more space to accommodate dislocation multiplication during plastic deformation. The strain-rate sensitivity evaluated via Lindholm's approach was observed to be higher in the base metal than in the welded samples.

  19. Shielding gas effects on flux cored arc welding of AISI 316L (N) austenitic stainless steel joints

    International Nuclear Information System (INIS)

    Highlights: ► The effects of shielding gasses are analyzed. ► The impact strength increases with increasing of percentage of CO2 in shielding gas mixtures. ► The ferrite percentage decreases with increasing of percentage of CO2 in shielding gas mixtures. ► Microhardness values increases with increasing of ferrite percentage in the weld metal. -- Abstract: This paper deals with the flux cored arc welding (FCAW) of AISI 316L (N) austenitic stainless steel with 1.2 mm diameter of flux cored 316LT filler wire. The welding was carried out with different shielding gas mixtures like 100% Ar, 95% Ar + 05% CO2, 90% Ar + 10% CO2, 80% Ar + 20% CO2, 75% Ar + 23% CO2 + 2% O2 and 70% Ar + 25% CO2 + 5% O2 and 100% CO2. The main aim of the work is to study the effect of various shielding gas mixtures on mechanical properties and metallurgical characters. The microstructures and ferrite content of the welds were analyzed. The mechanical characteristics such as impact test, microhardness and ductility of welds were carried out. The fracture surface impact samples were analyzed through scanning electron microscope (SEM). The fracture surface revealed a ductile rupture at room temperature and ductile rupture with a few cleavages at lower temperatures occurred. The toughness and ferrite percentages of the welds were decreased for increase of the CO2 in shielding gas mixtures.

  20. Effects of mechanical heterogeneity on the tensile and fatigue behaviours in a laser-arc hybrid welded aluminium alloy joint

    International Nuclear Information System (INIS)

    Highlights: • Full field strain evolution was characterized using DIC method in fatigue test. • The differences of fatigue failure mechanism between HAZ and FZ were discussed. • Porosity in FZ significantly influenced high cycle fatigue behaviours of the weld. - Abstract: The effects of mechanical heterogeneity on the tensile and high cycle fatigue (104–107 cycles) properties were investigated for laser-arc hybrid welded aluminium alloy joints. Tensile–tensile cyclic loading with a stress ratio of 0.1 was applied in a direction perpendicular to the weld direction for up to 107 cycles. The local mechanical properties in the tensile test and the accumulated plastic strain in the fatigue test throughout the weld’s different regions were characterized using a digital image correlation technique. The tensile results indicated heterogeneous tensile properties throughout the different regions of the aluminium welded joint, and the heat affected zone was the weakest region in which the strain localized. In the fatigue test, the accumulated plastic strain evolutions in different subzones of the weld were analyzed, and slip bands could be clearly observed in the heat affected zone. A transition of fatigue failure locations from the heat affected zone caused by accumulated plastic strain to the fusion zone induced by fatigue crack at pores could be observed under different cyclic stress levels. The welding porosity in the fusion zone significantly influences the high cycle fatigue behaviour

  1. Comparative Analysis on Welding Residual Stress of SS400 Sheet Metal Between Manual Electric Arc Welding and Argon Arc Welding%SS400薄板手工电弧焊和氩弧焊残余应力对比分析

    Institute of Scientific and Technical Information of China (English)

    麻相湑; 麻永林; 邢淑清; 陈重毅; 陆恒昌; 贺鸿臻

    2014-01-01

    In order to study the distribution rule of SS400 sheet under different welding residual stress, manual electric arc welding and argon arc welding method were used to weld 4 mm low alloy high strength steel. The residual stress of steel plate after welding was measured by the blind hole method, and the distribution curve of residual stress was obtained. The experimental results showed that: for manual electric arc welding the maximum value of residual stress in welding zone vertical direction is 387 MPa, the residual stress is compressive stress beside weld both sides, the compressive stress value is the maximum in the distance of 12 mm from weld both sides. The residual stress is tensile stress in center position in parallel welding direction;it is compressive stress beside both sides of weldments, and the compressive stress increases close to edge. For argon arc welding, the maximum value of tensile stress in vertical direction is 328 MPa, the compressive stress value is the maximum in the distance of 7 mm from weld both sides. The residual stress curve in parallel welding direction of argon arc welding is similar to that of manual electric arc welding, and welding deformation of argon arc welding is less than manual electric arc welding.%为了研究SS400钢板不同焊接方法残余应力的分布规律,分别对4 mm厚的低合金高强钢采用手工电弧焊和氩弧焊进行焊接,焊接后采用盲孔法测量钢板的残余应力,得到了残余应力的分布曲线。试验结果表明:手工电弧焊在焊接区垂直焊接方向的残余应力最大值为387 MPa,在焊缝两侧为压应力,距离焊缝两侧12 mm处,压应力最大;平行焊接方向上的残余应力在中间位置为拉应力,在工件两边为压应力,靠近边缘压应力增大。氩弧焊垂直于焊接方向上的最大拉应力为328 MPa,在焊缝两侧的距离为7 mm处,压应力最大;平行于焊接方向上的残余应力曲线与手工电弧焊

  2. Television system for automatic control of electrode position during argon arc welding of large-sized components

    International Nuclear Information System (INIS)

    The article deals with a TV system designed for controlling the position of electrode during argon-arc welding of butt joints with deep bevelling (levelling depth exceeds 10 mm). The operation of the system is based on the processing of bevelling images. The application of the system ensures the travel of the electrode along bevelling axis with an accuracy ±1 mm, minimum. 2 refs., 3 figs

  3. The role of Ti carbonitride precipitates on fusion zone strength-toughness in submerged arc welded linepipe joints

    Energy Technology Data Exchange (ETDEWEB)

    Aucott, L., E-mail: la126@le.ac.uk [Department of Engineering, University of Leicester (United Kingdom); Wen, S.W., E-mail: shuwen.wen@tatasteel.com [Department of Engineering, University of Leicester (United Kingdom); Tata Steel, Swinden Technology Centre, Rotherham (United Kingdom); Dong, H., E-mail: hd38@le.ac.uk [Department of Engineering, University of Leicester (United Kingdom)

    2015-01-12

    The role of micro-alloying in the submerged arc welding (SAW) of high strength low alloy steel linepipe is paramount in facilitating the high strength properties of the linepipe. In this study, transmission electron microscopy analysis revealed the presence of large (0.85 µm) Ti (C,N) precipitates within the predominantly acicular ferrite SAW joint. Cross-weld Vickers hardness and Charpy impact tests revealed that the fusion zone has high hardness and low toughness properties in relation to the base metal and heat affected zone. Fractography observations made on the ductile fracture surface of the fusion zone revealed a high number of the large Ti (C,N) precipitates to be located within the microvoids – suggesting their role in nucleating microvoids. Finally, fracture micro-mechanics are used to evaluate the relationship between the coarse precipitates and reduced strength-toughness properties in the SAW weld of the API-5L grade X65 linepipe steel.

  4. The role of Ti carbonitride precipitates on fusion zone strength-toughness in submerged arc welded linepipe joints

    International Nuclear Information System (INIS)

    The role of micro-alloying in the submerged arc welding (SAW) of high strength low alloy steel linepipe is paramount in facilitating the high strength properties of the linepipe. In this study, transmission electron microscopy analysis revealed the presence of large (0.85 µm) Ti (C,N) precipitates within the predominantly acicular ferrite SAW joint. Cross-weld Vickers hardness and Charpy impact tests revealed that the fusion zone has high hardness and low toughness properties in relation to the base metal and heat affected zone. Fractography observations made on the ductile fracture surface of the fusion zone revealed a high number of the large Ti (C,N) precipitates to be located within the microvoids – suggesting their role in nucleating microvoids. Finally, fracture micro-mechanics are used to evaluate the relationship between the coarse precipitates and reduced strength-toughness properties in the SAW weld of the API-5L grade X65 linepipe steel

  5. Nitrogen and oxygen concentration in zirconium alloy with 2,5 % niobium after arc welding in controlled atmosphere

    International Nuclear Information System (INIS)

    Results on investigation of kinetics and mechanism of nitrogen and oxygen interaction with Zr alloy with 2.5% niobium are presented for the process of arc welding at partial pressure of nitrogen and oxygen in helium within the 10-5000 Pa pressure range. It is established that equilibrium gas concentration is achieved after 16-20 s of melting. Nitrogen absorption is governed by the basic Siverts law and oxygen - by the Henry law. Increase of welding rate from 0.28 up to 1.68 cm/s decreases a degree of weld metal saturation with nitrogen and oxygen. Equations allowing to calculate concentrations of nitrogen and oxygen absorbed by melted weldpool metal are suggested

  6. Effect of Included Angle in V-Groove Butt Joints on Shrinkages in Submerged Arc Welding Process

    Directory of Open Access Journals (Sweden)

    N. LAKSHMANA SWAMY

    2012-04-01

    Full Text Available The problems of distortion, residual stresses and reduced strength of structure in and around a welded joint are of major concern in the shipbuilding industry and in other similar manufacturing industries. The predictions of the degree of shrinkages in ship panels due to welding are of great importance from the point of view of dimensional control and it is important to analyze transverse and longitudinal shrinkage. This paper deals with the experimental analysis of transverse and longitudinal shrinkage in single and double V-groove butt joints in submerged arc welding by varying included angle and keeping process parameters constant. It is found that, the maximum shrinkage was at the centre of the plate and minimum at the ends. It is also found that, the transverse and longitudinal shrinkage increase with increase in the included angle. There is a significant increase in the transverse shrinkage and small variation in longitudinal shrinkage.

  7. Edge detection and its application to recognition of arc weld image

    Institute of Scientific and Technical Information of China (English)

    Chen Xizhang; Lin Tao; Lang Yuyou; Chen Shanben

    2007-01-01

    Image sensor has been one of the key technologies in intellectualized robotics welding. Edge detection plays an important role when the vision technology is applied in intellectualized welding robotics technologies. There are all kinds of noises in welding environment. The algorithms in common use cannot be applied to the recognition of welding environment directly. The edge of images can be fell into four types. The weld images are classified by the characteristic of welding environment in this paper. This paper analyzes some algorithms of edge detection according to the character of welding image, some relative advantages and disadvantages are pointed out when these algorithms are used in this field, and some suggestions are given. The feature extraction of weld seam and weld pool are two typical problems in the realization of intellectualized welding. Their edge features are extracted and the results show the applicability of different edge detectors. The tradeoff between precision and calculated time is also considered for different application.

  8. Microstructural changes of a thermally aged stainless steel submerged arc weld overlay cladding of nuclear reactor pressure vessels

    International Nuclear Information System (INIS)

    The effect of thermal aging on microstructural changes in stainless steel submerged arc weld-overlay cladding of reactor pressure vessels was investigated using atom probe tomography (APT). In as-received materials subjected to post-welding heat treatments (PWHTs), with a subsequent furnace cooling, a slight fluctuation of the Cr concentration was observed due to spinodal decomposition in the δ-ferrite phase but not in the austenitic phase. Thermal aging at 400 °C for 10,000 h caused not only an increase in the amplitude of spinodal decomposition but also the precipitation of G phases with composition ratios of Ni:Si:Mn = 16:7:6 in the δ-ferrite phase. The degree of the spinodal decomposition in the submerged arc weld sample was similar to that in the electroslag weld one reported previously. We also observed a carbide on the γ-austenite and δ-ferrite interface. There were no Cr depleted zones around the carbide.

  9. Gas shielded metal arc welding with fusible electrode wire. First returns on experience and opportunities in nuclear maintenance and fabrication

    International Nuclear Information System (INIS)

    In a brief text and a Power Point Presentation, the authors report a return on experience for the implementation of two applications using gas shielded metal arc welding process (GMAW): the on-site welding of the final joint of steam generators, and the coating of a tubing flare. In the first case, the authors analyze not only the compliance with specified technical requirements, but also outline the need to support the process with new verification methods in real time, associated development and validation efforts, and organisational and decisional measures to guarantee a good implementation of the process on site. In the second case, they analyze the process ability to meet technical specifications requiring dilution control, a perfect reproducibility, as well a good control of the welding bath. The authors outline that these two applications which are both using the same term (gas shielded metal arc welding with fusible electrode wire), implement two different transfer regimes and processes. They also discuss operational constraints, and technical opportunities and constraints of fusible electrode wire

  10. Real time error detection in metal arc welding process using Artificial Neural Netwroks

    OpenAIRE

    Sharma, Prashant; Shaju K. Albert; Rajeswari, S.

    2016-01-01

    Quality assurance in production line demands reliable weld joints. Human made errors is a major cause of faulty production. Promptly Identifying errors in the weld while welding is in progress will decrease the post inspection cost spent on the welding process. Electrical parameters generated during welding, could able to characterize the process efficiently. Parameter values are collected using high speed data acquisition system. Time series analysis tasks such as filtering, pattern recognit...

  11. Joining of Materials with Diferent Properties Through Submerged Arc Welding Process and Destructive and Non-Destructive Testing of the Joints

    Directory of Open Access Journals (Sweden)

    Yakup Kaya

    2013-01-01

    Full Text Available In this study, X60, X65 and X70 steels used in petroleum and natural gas pipeline were joined with Submerged Arc Welding by using different type of welding fluxes (LN761 and P223 and wires (S1 and S2Mo. Initially, visual and radiographic inspection techniques were subjected to welded joints for determining surface and subsurface defects. After that, spectral analyses were carried out in order to determine the compositions of wire-flux-base metal on the joints. Impact toughness test were performed for determining toughness properties the joints. Furthermore, hardness and microstructure studies were also carried out on the samples. As a result of the visual and radiographic inspection on the welded samples, there were no weld defects on joints were observed. It was clearly understood that carbon ratio in the compositions of weld metal higher than base metal but lower than filler metal in terms of spectral analyses results. According to impact toughness test results, the joints obtained by using S2Mo welding wire and P223 welding flux had better impact toughness value than the joints obtained by S1 welding wire and LN 761 welding flux. With respect to hardness test, the highest hardness values were measured on weld metal. When the microstructure images were examined, it is clearly understood that similar images for all the joints were shown adjacent zones to weld metals heat affected zones and welding boundary, due to heat input constant.

  12. 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.

  13. Effect of Post-Weld Heat Treatment on Mechanical and Electrochemical Properties of Gas Metal Arc-Welded 316L (X2CrNiMo 17-13-2) Stainless Steel

    Science.gov (United States)

    Muhammad, F.; Ahmad, A.; Farooq, A.; Haider, W.

    2016-08-01

    In the present research work, corrosion behavior of post-weld heat-treated (PWHT) AISI 316L (X2CrNiMo 17-13-2) specimens joined by gas metal arc welding is compared with as-welded samples by using potentiodynamic polarization technique. Welded samples were PWHT at 1323 K for 480 s and quenched. Mechanical properties, corrosion behavior and microstructures of as-welded and PWHT specimens were investigated. Microstructural studies have shown grain size refinement after PWHT. Ultimate tensile strength and yield strength were found maximum for PWHT samples. Bend test have shown that PWHT imparted ductility in welded sample. Fractographic analysis has evidenced ductile behavior for samples. Potentiodynamic polarization test was carried out in a solution composed of 1 M H2SO4 and 1 N NaCl. Corrosion rate of weld region was 127.6 mpy, but after PWHT, it was decreased to 13.12 mpy.

  14. Reinforcements affect mechanical properties and wear behaviors of WC clad layer by gas tungsten arc welding

    International Nuclear Information System (INIS)

    Highlights: ► WC particles react completely with the steel matrix during the GTAW process. ► The same specimen has different morphologies under the SEM and OM. ► The evolution of this microstructure is proposed. ► Fe3W3C and M7C3 phases clearly affected the hardness and wear performance. -- Abstract: This work deals with the surface analysis, mechanical properties and wear performances of the clad layer, which is made from tungsten carbide (WC) powders on SKD61 die steel by the gas tungsten arc welding method. According to the experimental results, due to the high hardness and elastic modulus reinforcements (Fe3W3C and M7C3) existing in the WC clad layer, the WC clad specimen has excellent wear performance at different sliding speeds. According to the wear analysis, wear behaviors of the WC clad layer are two-body abrasion and oxidation wear. In addition, oxidation wear dominates the wear behaviors of the SKD61 die steel specimen at different sliding speeds.

  15. 锅炉筒体内环焊缝埋弧自动焊机%Research on submerged arc welding machine designed on inner circular welding for the boiler

    Institute of Scientific and Technical Information of China (English)

    沙玉章; 张晓明; 邢铁刚

    2011-01-01

    普通的埋孤焊接小车和焊接操作架无法进入锅炉筒体内实施焊接,锅炉筒体组合最后一道内环焊缝的焊接一直采用手工焊接.研发的锅炉筒体内环焊缝埋弧自动焊机的核心部分为焊接小车、焊缝跟踪器和焊枪调整机构,焊接电源、筒体转胎和焊丝盘为常规设备.其创新之处在于:一是焊接小车体积小、质量轻,一个工人即可将其搬出、入筒体人孔;二是焊接小车配置了功能完善的机械式焊缝跟踪器,保证焊接小车始终准确可靠地与焊缝平行等距行走,即保证在焊接过程中焊枪始终不偏离焊缝.实现了焊缝的优质高效自动化焊接,焊缝探伤合格率达98%以上,焊缝宽度均匀,表面光滑美观,填补了此项焊接专机在国内的空白.%Because ordinary submerged arc welding carriage and welding operation frame could not go into the boiler the cylinder for inner welding,the final inner welding seam has been using manual welding.The core part of developed boiler cylindrical shell inner weld seam submerged arc welder are the welding carriage,seam tracking device and welding torch regulator,the welding power source,barrel turn tire and wire reel are conventional equipments.The innovation of this research are those:First,welding carriage has small size, lightweight, only one worker can move into and out of the cylinder manhole; Second, the welding carriage is configured a fully functioning mechanical welding seam tracker,ensuring that the car always reliable way and weld parallel isometric moving, namely that welding torch always not deviating from the welding seam in the welding process.Realize the welding line of automatic welding quality and efficient,weld qualified rate above 98%,and the weld width uniformity,the surface is smooth and beautiful,fill the welding machine in domestic blank.

  16. Plasma arc welding of AISI316Ti (EN 1.4571) stainless steel. Mechanical, microstructural, corrosion aspects

    Energy Technology Data Exchange (ETDEWEB)

    Taban, Emel; Kaluc, Erdinc [Kocaeli Univ. (Turkey). Dept. of Mechanical Engineering

    2014-03-01

    AISI316Ti (EN1.4571) austenitic stainless steel plates with a thickness of 7 mm were welded by plasma arc welding (PAW) process. Joints were obtained using 316L type of filler metal as well as without filler metal called as Weld 1 and Weld 2, respectively. Tensile and bend testing of the joints were carried out. Impact toughness tests carried out at temperatures from 20 C down to -60 C have shown encouraging results. Chemical analysis of the weld deposits were made by glow discharge optical emission spectrometry (GDOES). Photomacrographs and photomicrographs of the cross-sections were used to determine ferrite content and hardness. Intergranular corrosion tests in accordance with TSEN 3157/ENISO 3651-2 were carried out. No corrosion sign was reported. The effect of the consumable has the most influence on the toughness properties. Promising mechanical, toughness and corrosion results are useful, considering the implementation of an innovative process, thus PAW of 316Ti stainless steel. (orig.)

  17. Fatigue crack growth behaviour of gas tungsten arc, electron beam and laser beam welded Ti-6Al-4V alloy

    International Nuclear Information System (INIS)

    Highlights: → The available data focus on stress ratio, microstructure and residual stress on crack growth. → No literature available on fatigue behaviour of GTAW, LBW and EBW joints of Ti-Al-4V alloys. → This study compares the fatigue crack growth rate of GTAW, LBW and EBW joints of Ti-6Al-4V alloy. -- Abstract: The present investigation is aimed to evaluate fatigue crack growth parameters of gas tungsten arc, electron beam and laser beam welded Ti-6Al-4V titanium alloy for assessing the remaining service lives of existing structure by fracture mechanics approach. Center cracked tensile specimens were tested using a 100 kN servo hydraulic controlled fatigue testing machine under constant amplitude uniaxial tensile load. Crack growth curves were plotted and crack growth parameters (exponent and intercept) were evaluated. Fatigue crack growth behavior of welds was correlated with mechanical properties and microstructural characteristics of welds. Of the three joints, the joint fabricated by laser beam welding exhibited higher fatigue crack growth resistance due to the presence of fine lamellar microstructure in the weld metal.

  18. Plasma arc welding of AISI316Ti (EN 1.4571) stainless steel. Mechanical, microstructural, corrosion aspects

    International Nuclear Information System (INIS)

    AISI316Ti (EN1.4571) austenitic stainless steel plates with a thickness of 7 mm were welded by plasma arc welding (PAW) process. Joints were obtained using 316L type of filler metal as well as without filler metal called as Weld 1 and Weld 2, respectively. Tensile and bend testing of the joints were carried out. Impact toughness tests carried out at temperatures from 20 C down to -60 C have shown encouraging results. Chemical analysis of the weld deposits were made by glow discharge optical emission spectrometry (GDOES). Photomacrographs and photomicrographs of the cross-sections were used to determine ferrite content and hardness. Intergranular corrosion tests in accordance with TSEN 3157/ENISO 3651-2 were carried out. No corrosion sign was reported. The effect of the consumable has the most influence on the toughness properties. Promising mechanical, toughness and corrosion results are useful, considering the implementation of an innovative process, thus PAW of 316Ti stainless steel. (orig.)

  19. In-Situ Phase Mapping and Direct Observations of Phase Transformations During Arc Welding of 1045 Steel

    Energy Technology Data Exchange (ETDEWEB)

    Elmer, J; Palmer, T

    2005-09-13

    In-situ Spatially Resolved X-Ray Diffraction (SRXRD) experiments were performed during gas tungsten arc (GTA) welding of AISI 1045 C-Mn steel. Ferrite ({alpha}) and austenite ({gamma}) phases were identified and quantified in the weld heat-affected zone (HAZ) from the real time x-ray diffraction data. The results were compiled along with weld temperatures calculated using a coupled thermal fluids weld model to create a phase map of the HAZ. This map shows the {alpha} {yields} {gamma} transformation taking place during weld heating and the reverse {gamma} {yields} {alpha} transformation taking place during weld cooling. Superheating is required to complete the {alpha} {yields} {gamma} phase transformation, and the amount of superheat above the A3 temperature was shown to vary with distance from the centerline of the weld. Superheat values as high as 250 C above the A3 temperature were observed at heating rates of 80 C/s. The SRXRD experiments also revealed details about the {gamma} phase not observable by conventional techniques, showing that {gamma} is present with two distinct lattice parameters as a result of inhomogeneous distribution of carbon and manganese in the starting pearlitic/ferritic microstructure. During cooling, the reverse {gamma} {yields} {alpha} phase transformation was shown to depend on the HAZ location. In the fine grained region of the HAZ, at distances greater than 2 mm from the fusion line, the {gamma} {yields} {alpha} transformation begins near the A3 temperature and ends near the A1 temperature. In this region of the HAZ where the cooling rates are below 40 C/s, the transformation occurs by nucleation and growth of pearlite. For HAZ locations closer to the fusion line, undercoolings of 200 C or more below the A1 temperature are required to complete the {gamma} {yields} {alpha} transformation. In this region of the HAZ, grain growth coupled with cooling rates in excess of 50 C/s causes the transformation to occur by a bainitic mechanism.

  20. Dynamic Resource Allocation with the arcControlTower

    Science.gov (United States)

    Filipčič, A.; Cameron, D.; Nilsen, J. K.

    2015-12-01

    Distributed computing resources available for high-energy physics research are becoming less dedicated to one type of workflow and researchers workloads are increasingly exploiting modern computing technologies such as parallelism. The current pilot job management model used by many experiments relies on static dedicated resources and cannot easily adapt to these changes. The model used for ATLAS in Nordic countries and some other places enables a flexible job management system based on dynamic resources allocation. Rather than a fixed set of resources managed centrally, the model allows resources to be requested on the fly. The ARC Computing Element (ARC-CE) and ARC Control Tower (aCT) are the key components of the model. The aCT requests jobs from the ATLAS job management system (PanDA) and submits a fully-formed job description to ARC-CEs. ARC-CE can then dynamically request the required resources from the underlying batch system. In this paper we describe the architecture of the model and the experience of running many millions of ATLAS jobs on it.

  1. CHEP2015: Dynamic Resource Allocation with arcControlTower

    CERN Document Server

    Filipcic, Andrej; The ATLAS collaboration; Nilsen, Jon Kerr

    2015-01-01

    Distributed computing resources available for high-energy physics research are becoming less dedicated to one type of workflow and researchers’ workloads are increasingly exploiting modern computing technologies such as parallelism. The current pilot job management model used by many experiments relies on static dedicated resources and cannot easily adapt to these changes. The model used for ATLAS in Nordic countries and some other places enables a flexible job management system based on dynamic resources allocation. Rather than a fixed set of resources managed centrally, the model allows resources to be requested on the fly. The ARC Computing Element (ARC-CE) and ARC Control Tower (aCT) are the key components of the model. The aCT requests jobs from the ATLAS job mangement system (Panda) and submits a fully-formed job description to ARC-CEs. ARC-CE can then dynamically request the required resources from the underlying batch system. In this paper we describe the architecture of the model and the experience...

  2. Dynamic Resource Allocation with the arcControlTower

    CERN Document Server

    Filipcic, Andrej; The ATLAS collaboration; Nilsen, Jon Kerr

    2015-01-01

    Distributed computing resources available for high-energy physics research are becoming less dedicated to one type of workflow and researchers’ workloads are increasingly exploiting modern computing technologies such as parallelism. The current pilot job management model used by many experiments relies on static dedicated resources and cannot easily adapt to these changes. The model used for ATLAS in Nordic countries and some other places enables a flexible job management system based on dynamic resources allocation. Rather than a fixed set of resources managed centrally, the model allows resources to be requested on the fly. The ARC Computing Element (ARC-CE) and ARC Control Tower (aCT) are the key components of the model. The aCT requests jobs from the ATLAS job management system (PanDA) and submits a fully-formed job description to ARC-CEs. ARC-CE can then dynamically request the required resources from the underlying batch system. In this paper we describe the architecture of the model and the experienc...

  3. Pengaruh Proses Quenching Pada Sambungan Las Shielded Metal Arc Welding (Smaw) Terhadap Kekerasan Impak Struktur Mikro Dan Kekerasan Baja St37

    OpenAIRE

    Halim, Jumain

    2015-01-01

    Toughness of a material is influenced by the physical and mechanical properties of these materials. However, the joining by using the welding process cause a change in the properties. Has been conducted research by using welding shielded metal arc welding (SMAW) in the process of joining St37 steel to determine the physical and mechanical properties with variation of electrode diameter (2.6 mm, 3,2mm and 4,0 mm) and different cooling processes. After the welding treatment, the specimen is sub...

  4. 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…

  5. Modeling Arcs

    CERN Document Server

    Insepov, Zeke; Veitzer, Seth; Mahalingam, Sudhakar

    2011-01-01

    Although vacuum arcs were first identified over 110 years ago, they are not yet well understood. We have since developed a model of breakdown and gradient limits that tries to explain, in a self-consistent way: arc triggering, plasma initiation, plasma evolution, surface damage and gra- dient limits. We use simple PIC codes for modeling plasmas, molecular dynamics for modeling surface breakdown, and surface damage, and mesoscale surface thermodynamics and finite element electrostatic codes for to evaluate surface properties. Since any given experiment seems to have more variables than data points, we have tried to consider a wide variety of arcing (rf structures, e beam welding, laser ablation, etc.) to help constrain the problem, and concentrate on common mechanisms. While the mechanisms can be comparatively simple, modeling can be challenging.

  6. STUDY ON DYNAMIC J-INTEGRAL OF MECHANICAL HETEROGENEOUS WELDED JOINT

    Institute of Scientific and Technical Information of China (English)

    F.Q. Tian; D.Y. He; X.Y. Li; Y.W. Shi; D. Zhang

    2004-01-01

    Welded joint is a mechanical heterogeneous body, and mechanical heterogeneity has great effect on dynamic fracture behaviour of welded joints. In the present investigation, dynamic response curve and dynamic J-integral of practical undermatched welded joint and whole base and whole weld three-point-bend (TPB) models containing longitudinal crack are computed. Dynamic J-integral is evaluated using virtual crack extension (VCE) method and the computation is performed using MARC finite element code. Because of the effect of inertia,dynamic load response curve of computed model waves periodically. Dynamic J-integral evaluated by VCE method is path independent. The effect of inertia has little influence on dynamic J-integral curve. The value of dynamic J-integral of undermatched welded joint is lower than that of whole base metal and higher than that of whole weld metal. The results establish the foundation of safety evaluation for dynamic loaded welded structures.

  7. Multitasking the code ARC3D. [for computational fluid dynamics

    Science.gov (United States)

    Barton, John T.; Hsiung, Christopher C.

    1986-01-01

    The CRAY multitasking system was developed in order to utilize all four processors and sharply reduce the wall clock run time. This paper describes the techniques used to modify the computational fluid dynamics code ARC3D for this run and analyzes the achieved speedup. The ARC3D code solves either the Euler or thin-layer N-S equations using an implicit approximate factorization scheme. Results indicate that multitask processing can be used to achieve wall clock speedup factors of over three times, depending on the nature of the program code being used. Multitasking appears to be particularly advantageous for large-memory problems running on multiple CPU computers.

  8. 船舶电气支件焊接中电弧螺柱焊技术的应用%Application of Arc Stud Welding Technology in Marine Electrical Branch Welding

    Institute of Scientific and Technical Information of China (English)

    郭佳

    2015-01-01

    The arc stud welding technology is a widely used welding method,has high stud welding efficiency and many advantages,such as: easy to realize automative control,high welding efficiency. While as for the marine electrical branch welding,in order to avoid the damage of traditional welding technology to the ship pre-coating,we must use special welding technology to replace the traditional shielded metal arc welding. Therefore,this paper studied the machine type selection,parameters selection and other aspects,proved that the arc stud welding technology can effectively improve the efficiency of welding and control the welding quality.%电弧螺柱焊接技术是一种被广泛应用的焊接方法,拥有很高的螺柱焊接效率,具有很多优点,比如:容易实现自动化控制、焊接效率高等。而对船舶电气支件焊接来说,要想避免传统焊接技术对船舶预涂层的破坏,就要采用专用的焊接技术来代替传统的焊条电弧焊。因此,本文对机器的选型、参数的选定等进行了研究,证明电弧螺柱焊接技术能够有效地提高焊接效率,控制焊接质量。

  9. Experimental and theoretical studies on keyhole dynamics in laser welding

    Energy Technology Data Exchange (ETDEWEB)

    Matsunawa, Akira; Katayama, Seiji; Kim, Jong-Do [Osaka Univ. (Japan); Semak, V.V. [Univ. of Tennessee Space Institute, Tullahoma, TN (United States)

    1996-12-31

    The present paper describes the results of high speed photography, acoustic emission (AE) detection and plasma light emission (LE) measurement during CO{sub 2} laser welding of 304 stainless steel in different processing conditions. Video images with high spatial and temporal resolution allowed observation of the melt dynamics and keyhole evolution. The existence of a high speed melt flow which originated from the front part of weld pool and flowed along the sides wall of keyhole was confirmed by the slag motion on the weld pool. The characteristic frequencies of flow instability and keyhole fluctuations at different welding speed were measured and compared with the results of Fourier analyses of temporal AE and LE spectra. The experimental results were compared with the newly developed numerical model of keyhole dynamics. The model is based on the assumption that the propagation of front part of keyhole into material is due to the melt ejection driven by laser induced surface evaporation. The calculations predict that a high speed melt flow is induced at the front part of keyhole when the sample travel speed exceeds several 10 mm/s. The numerical analysis also shows the hump formation on the front keyhole wall surface. Experimentally observed melt behavior and transformation of the AE and LE spectra with variation of welding speed are qualitatively in good agreement with the model predictions.

  10. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    International Nuclear Information System (INIS)

    Highlights: • Electromagnetic interaction in welding improved localised corrosion resistance. • Electromagnetic interaction in welding enhanced γ/δ phase balance of DuplexSS. • Welding under Electromagnetic interaction repress formation and growth of detrimental phases. • Welds made with gas protection (2% O2 + 98% Ar) have better microstructural evolution during welding. - Abstract: The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O2 (M1) and 97% Ar + 3% N2 (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack

  11. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    Energy Technology Data Exchange (ETDEWEB)

    García-Rentería, M.A., E-mail: crazyfim@gmail.com [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); López-Morelos, V.H., E-mail: vhlopez@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); García-Hernández, R., E-mail: rgarcia@umich.mx [Instituto de Investigación en Metalurgia y Materiales, Universidad Michoacana de San Nicolás de Hidalgo, A.P. 888, CP 58000, Morelia, Michoacán (Mexico); Dzib-Pérez, L., E-mail: luirdzib@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); García-Ochoa, E.M., E-mail: emgarcia@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico); González-Sánchez, J., E-mail: jagonzal@uacam.mx [Centre for Corrosion Research, Autonomous University of Campeche, Av. Agustín Melgar s/n, Col. Buenavista, CP 24039, Campeche, Cam (Mexico)

    2014-12-01

    Highlights: • Electromagnetic interaction in welding improved localised corrosion resistance. • Electromagnetic interaction in welding enhanced γ/δ phase balance of DuplexSS. • Welding under Electromagnetic interaction repress formation and growth of detrimental phases. • Welds made with gas protection (2% O{sub 2} + 98% Ar) have better microstructural evolution during welding. - Abstract: The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O{sub 2} (M1) and 97% Ar + 3% N{sub 2} (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  12. Measurement of Dynamic Resistance in Resistance Spot Welding

    DEFF Research Database (Denmark)

    Wu, Pei; Lu, J.; Zhang, Wenqi;

    2007-01-01

    The conventional methods of determining the dynamic resistance were mostly done by measuring the voltage and current at secondary side of transformer in resistance welding machines, in which the measuring set-up normally interferes with the movement of electrode, and the measuring precision is in...

  13. Mechanical properties of API X80 steel pipe joints welded by Flux Core Arc Weld Process; Propriedades mecanicas de juntas de tubos de aco API X80 soldadas com arame tubulares

    Energy Technology Data Exchange (ETDEWEB)

    Ordonez, Robert E. Cooper; Silva, Jose Hilton F.; Trevisan, Roseana E. [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Engenharia de Fabricacao

    2003-07-01

    Flux Core Arc Welding processes (FCAW) are beginning to be applied in pipeline welds, however, very limited experimental data regarding mechanical properties of pipeline weld joints with these processes are available in the literature. In this paper, the effects of preheat temperature and type of FCAW on mechanical properties (microhardness and tensile strength) of API X80 weld joint steel are presented. FCAW processes with gas protection and self-shielded were used. Multipasses welding were applied in 30'' diameter and 0,625'' thickness tubes. Influence factors were: FCAW type and preheat temperature. Acceptance criteria of welded joints were evaluated by API 1104 standard for tensile strength test and ASTM E384-99 for microhardness test. The results obtained showed that FCAW type and preheat temperature have no influence on mechanical properties of API X80 joint steel. (author)

  14. In situ droplet surface tension and viscosity measurements in gas metal arc welding

    International Nuclear Information System (INIS)

    In this paper, we present an adaptation of a drop oscillation technique that enables in situ measurements of thermophysical properties of an industrial pulsed gas metal arc welding (GMAW) process. Surface tension, viscosity, density and temperature were derived expanding the portfolio of existing methods and previously published measurements of surface tension in pulsed GMAW. Natural oscillations of pure liquid iron droplets are recorded during the material transfer with a high-speed camera. Frame rates up to 30000 fps were utilized to visualize iron droplet oscillations which were in the low kHz range. Image processing algorithms were employed for edge contour extraction of the droplets and to derive parameters such as oscillation frequencies and damping rates along different dimensions of the droplet. Accurate surface tension measurements were achieved incorporating the effect of temperature on density. These are compared with a second method that has been developed to accurately determine the mass of droplets produced during the GMAW process which enables precise surface tension measurements with accuracies up to 1% and permits the study of thermophysical properties also for metals whose density highly depends on temperature. Thermophysical properties of pure liquid iron droplets formed by a wire with 1.2 mm diameter were investigated in a pulsed GMAW process with a base current of 100 A and a pulse current of 600 A. Surface tension and viscosity of a sample droplet were 1.83 ± 0.02 N m-1 and 2.9 ± 0.3 mPa s, respectively. The corresponding droplet temperature and density are 2040 ± 50 K and 6830 ± 50 kg m-3, respectively. (paper)

  15. Improvement of localised corrosion resistance of AISI 2205 Duplex Stainless Steel joints made by gas metal arc welding under electromagnetic interaction of low intensity

    Science.gov (United States)

    García-Rentería, M. A.; López-Morelos, V. H.; García-Hernández, R.; Dzib-Pérez, L.; García-Ochoa, E. M.; González-Sánchez, J.

    2014-12-01

    The resistance to localised corrosion of AISI 2205 duplex stainless steel plates joined by Gas Metal Arc Welding (GMAW) under the effect of electromagnetic interaction of low intensity (EMILI) was evaluated with sensitive electrochemical methods. Welds were made using two shielding gas mixtures: 98% Ar + 2% O2 (M1) and 97% Ar + 3% N2 (M2). Plates were welded under EMILI using the M1 gas with constant welding parameters. The modified microstructural evolution in the high temperature heat affected zone and at the fusion zone induced by application of EMILI during welding is associated with the increase of resistance to localised corrosion of the welded joints. Joints made by GMAW using the shielding gas M2 without the application of magnetic field presented high resistance to general corrosion but high susceptibility to undergo localised attack.

  16. OPTIMIZATION OF PROCESS PARAMETERS TO MINIMIZE ANGULAR DISTORTION IN GAS TUNGSTEN ARC WELDED STAINLESS STEEL 202 GRADE PLATES USING PARTICLE SWARM OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    R. SUDHAKARAN

    2012-04-01

    Full Text Available This paper presents a study on optimization of process parameters using particle swarm optimization to minimize angular distortion in 202 grade stainless steel gas tungsten arc welded plates. Angular distortion is a major problem and most pronounced among different types of distortion in butt welded plates. The process control parameters chosen for the study are welding gun angle, welding speed, plate length, welding current and gas flow rate. The experiments were conducted using design of experiments technique with five factor five level central composite rotatable design with full replication technique. A mathematical model was developed correlating the process parameters with angular distortion. A source code was developed in MATLAB 7.6 to do the optimization. The optimal process parameters gave a value of 0.0305° for angular distortion which demonstrates the accuracy of the model developed. The results indicate that the optimized values for the process parameters are capable of producing weld with minimum distortion.

  17. 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.)

  18. Irradiation effects on fracture toughness of two high-copper submerged-arc welds, HSSI Series 5

    International Nuclear Information System (INIS)

    The Fifth Irradiation Series in the Heavy-Section Steel Irradiation Program obtained a statistically significant fracture toughness data base on two high-copper (0.23 and 0.31 wt %) submerged-arc welds to determine the shift and shape of the KIc curve as a consequence of irradiation. Compact specimens with thicknesses to 101.6 mm (4 in) in the irradiated condition and 203.2 mm (8 in) in the unirradiated condition were tested, in addition to Charpy impact, tensile, and drop-weight specimens. Irradiations were conducted at a nominal temperature of 288 degree C and an average fluence of 1.5 x 1019 neutrons/cm2 (>l MeV). The Charpy 41-J temperature shifts are about the same as the corresponding drop-weight NDT temperature shifts. The irradiated welds exhibited substantial numbers of cleavage pop-ins. Mean curve fits using two-parameter (with fixed intercept) nonlinear and linearized exponential regression analysis revealed that the fracture toughness 100 MPa lg-bullet √m shifts exceeded the Charpy 41-J shifts for both welds. Analyses of curve shape changes indicated decreases in the slopes of the fracture toughness curves, especially for the higher copper weld. Weibull analyses were performed to investigate development of lower bound curves to the data, including the use of a variable Kmin parameter which affects the curve shape

  19. Developing mathematical models to predict tensile properties of pulsed current gas tungsten arc welded Ti-6Al-4V alloy

    International Nuclear Information System (INIS)

    Titanium (Ti-6Al-4V) alloy has gathered wide acceptance in the fabrication of light weight structures requiring a high strength-to-weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. 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. Many considerations come into the picture and one need to carefully balance various pulse current parameters to arrive at an optimum combination. Hence, in this investigation an attempt has been made to develop mathematical models to predict tensile properties of pulsed current GTA welded titanium alloy weldments. Four factors, five level, central composite, rotatable design matrix is used to optimise the required number of experiments. The mathematical models have been developed by response surface method (RSM). The adequacy of the models has been checked by ANOVA technique. By using the developed mathematical models, the tensile properties of the joints can be predicted with 99% confidence level

  20. Effect of laser-arc hybrid welding on fracture and corrosion behaviour of AA6061-T6 alloy

    International Nuclear Information System (INIS)

    Research highlights: → A dendritic cellular structure was formed in the weld fusion zone (WFZ) and caused alloying element segregation. → The precipitation of intermetallic phases and the formation of galvanic corrosion couplings contribute to the improving pitting susceptibility in the WFZ. → The intergranular corrosion nucleates on pit walls and spreads from them. - Abstract: The welding condition of the hybrid laser-gas metal arc (GMA) welding for AA6061-T6 alloy was optimized by tensile test. Formability performance was checked by the bend test. Fractographic analysis indicates a large number of fine ductile type voids in the fracture surface. The microstructure measurements exhibit a dendritic cellular structure in the weld fusion zone (WFZ) and a partially melted zone adjacent to the fusion boundaries. The corrosion behaviour of the weldment and the base alloy were investigated by weight-loss test in nitric acid solution. The WFZ suffers more severe pitting than the rest regions in the weldment. It shows that corrosion cracking is owing to the precipitation of intermetallic phases and the formation of galvanic corrosion couplings in the weldment of AA6061-T6 alloy.

  1. Material property evaluations of bimetallic welds, stainless steel saw fusion lines, and materials affected by dynamic strain aging

    Energy Technology Data Exchange (ETDEWEB)

    Rudland, D.; Scott, P.; Marschall, C.; Wilkowski, G. [Battelle Memorial Institute, Columbus, OH (United States)

    1997-04-01

    Pipe fracture analyses can often reasonably predict the behavior of flawed piping. However, there are material applications with uncertainties in fracture behavior. This paper summarizes work on three such cases. First, the fracture behavior of bimetallic welds are discussed. The purpose of the study was to determine if current fracture analyses can predict the response of pipe with flaws in bimetallic welds. The weld joined sections of A516 Grade 70 carbon steel to F316 stainless steel. The crack was along the carbon steel base metal to Inconel 182 weld metal fusion line. Material properties from tensile and C(T) specimens were used to predict large pipe response. The major conclusion from the work is that fracture behavior of the weld could be evaluated with reasonable accuracy using properties of the carbon steel pipe and conventional J-estimation analyses. However, results may not be generally true for all bimetallic welds. Second, the toughness of austenitic steel submerged-arc weld (SAW) fusion lines is discussed. During large-scale pipe tests with flaws in the center of the SAW, the crack tended to grow into the fusion line. The fracture toughness of the base metal, the SAW, and the fusion line were determined and compared. The major conclusion reached is that although the fusion line had a higher initiation toughness than the weld metal, the fusion-line J-R curve reached a steady-state value while the SAW J-R curve increased. Last, carbon steel fracture experiments containing circumferential flaws with periods of unstable crack jumps during steady ductile tearing are discussed. These instabilities are believed to be due to dynamic strain aging (DSA). The paper discusses DSA, a screening criteria developed to predict DSA, and the ability of the current J-based methodologies to assess the effect of these crack instabilities. The effect of loading rate on the strength and toughness of several different carbon steel pipes at LWR temperatures is also discussed.

  2. Evaluation of human exposure to complex waveform magnetic fields generated by arc-welding equipment according to european safety standards

    International Nuclear Information System (INIS)

    In this paper, a procedure is described for the assessment of human exposure to magnetic fields with complex waveforms generated by arc-welding equipment. The work moves from the analysis of relevant guidelines and technical standards, underlining their strengths and their limits. Then, the procedure is described with particular attention to the techniques used to treat complex waveform fields. Finally, the procedure is applied to concrete cases encountered in the workplace. The discussion of the results highlights the critical points in the procedure, as well as those related to the evolution of the technical and exposure standards. (authors)

  3. Combination of self-shielded and gas-shielded flux-cored arc welding

    OpenAIRE

    Lian, Atle Korsnes

    2011-01-01

    This master thesis have consisted of experimental and theoretical studies of the change in microstructure and mechanical properties in intermixed weld metal from self-shielded and gas-shielded flux-cored welding wires. The main objective of the present thesis has been to do detailed metallographic analysis on different weld metal combinations, and find out and give an explanation why satisfying values were achieved or not achieved.The report is divided into four parts. Part one consists of re...

  4. The development of the underwater welding arc control system%水下焊接电弧控制系统的研制

    Institute of Scientific and Technical Information of China (English)

    梁明; 王国荣; 钟继光; 石永华; 廖宵

    2001-01-01

    At the special request of the flux-cored wire welding underwater,the welding arc control system is developed. The current waveform of the inverter power source is controlled by a microcomputer. The stability of arc and the formation of weld in underwater welding are improved, while the spatter is reduced.%根据药芯焊丝水下焊接的要求,研制了一套水下焊接电弧控制系统。本系统通过单片微机实时控制焊接电流波形,在进行水下短路过渡焊接时可以提高焊接电弧稳定性,减少飞溅,同时改善焊缝成型。

  5. The study of measuring technology on the dynamic mechanical properties of welded joint with high strain rate

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    In this paper, to meet the needs of studying work of dynamic mechanical properties of welded joint, the dynamic mechanical properties of welded joint were measured by means of SHPB(Split Hopkinson Pressure Bar).The dynamic mechanical property's curves of every part of welded joint were obtained. For studying the dynamic behavior of mechanical heterogeneity of welded joint, important data were offered. The method of test creates a new way of studying dynamic mechanical properties of welded joint.

  6. 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

  7. 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…

  8. Role of pulsed current on metallurgical and mechanical properties of dissimilar metal gas tungsten arc welding of maraging steel to low alloy steel

    International Nuclear Information System (INIS)

    Highlights: • Effect of current pulsing on weldability of maraging steel and low alloy steel. • Pensive discussions on the role of ErNiCrMo-3 filler on weld mechanical properties. • Improved strength and toughness on using pulsed gas tungsten arc welding. - Abstract: This research work encompasses the investigations carried out on the mechanical and metallurgical properties of maraging steel and AISI 4340 aeronautical steel weldments. The materials were joined by continuous current gas tungsten arc welding (CCGTA) and pulse current (PCGTA) gas tungsten arc welding processes using ErNiCrMo-3 filler wire. Cross sectional macrostructures confirmed proper deposition of the fillers and lack of discontinuities. Optical microscopy studies revealed that at the maraging steel–weld interface, martensite in distorted and block forms prevailed in CCGTA and PCGTA weldments whereas tempered martensite was predominant at the low alloy–weld interfaces of both the welds. Scanning electron microscopy (SEM) with energy dispersive analysis of X-rays (EDAX) analysis apparently showed less elemental migration in PCGTA weldments as compared to the other. Results of X-ray diffraction analysis recorded possible phase formations in various zones of the weldments. Microhardness profiles in either weld zones followed a constant trend whereas it showed a downtrend in the heat affected zones (HAZ) of the maraging steel and very high hardness profiles were observed in the low alloy steel side. Tensile studies on various factors and impact testing showed that PCGTA weldments outperformed the continuous ones in terms of strength, ductility and toughness. Fractograph analysis depicted the nature of failures of tensile and impact tested specimens. Comparison analyses involving influence and nature of pulsed current welds over continuous ones were done to determine the possibility of implementing these joining processes in aerospace applications. Weldments fabricated using PCGTA technique

  9. Dynamic process of angular distortion between aluminum and titanium alloys with TIG welding

    Institute of Scientific and Technical Information of China (English)

    WANG Rui; LIANG Zhen-xin; ZHANG Jian-xun

    2008-01-01

    The dynamic process of welding angular distortion in the overlaying welding of 5A12 aluminum alloy and BT20 titanium alloy was investigated. Information of dynamic distortion was got via self-made welding dynamic measuring system. Research results show that the characteristics of dynamic distortions at various positions of the plate edge parallel to the weld of 5A12 and BT20 alloy are different. Comparison between 5A12 and BT20 alloy shows that transverse shrinkage and downward longitudinal bending are main factors influencing the dynamic angular distortion processes of 5A12 and BT20 alloy under welding heat input of 0.32 kJ/mm. The angular distortion of 5A12 alloy is completely inversed with welding heat input increasing to 0.4 kJ/mm, and the position of weld center and buckling distortion become the primary factors.

  10. Investigations of the contact bounce behaviors and relative dynamic welding phenomena for electromechanical relay

    Science.gov (United States)

    Ren, Wanbin; He, Yuan; Jin, Jianbing; Man, Sida

    2016-06-01

    Dynamic welding, being the principal mechanism of sticking failure, correlates closely with the contact bounce of electromechanical relay. The typical waveforms of dynamic contact force and contact voltage at making and breaking process are obtained with the use of a new designed test rig. The variations in bounce time, bounce numbers, last bounce duration, and relevant welding force are investigated in the electrical endurance test. It is determined that the welding strength and the welding probability are increased with the reduced stationary force. The degradation physical mechanism is present to better understand the relationship between dynamic welding and operation characteristics of electromechanical relay.

  11. Investigations of the contact bounce behaviors and relative dynamic welding phenomena for electromechanical relay.

    Science.gov (United States)

    Ren, Wanbin; He, Yuan; Jin, Jianbing; Man, Sida

    2016-06-01

    Dynamic welding, being the principal mechanism of sticking failure, correlates closely with the contact bounce of electromechanical relay. The typical waveforms of dynamic contact force and contact voltage at making and breaking process are obtained with the use of a new designed test rig. The variations in bounce time, bounce numbers, last bounce duration, and relevant welding force are investigated in the electrical endurance test. It is determined that the welding strength and the welding probability are increased with the reduced stationary force. The degradation physical mechanism is present to better understand the relationship between dynamic welding and operation characteristics of electromechanical relay. PMID:27370500

  12. The characterization investigation of laser-arc-adhesive hybrid welding of Mg to Al joint using Ni interlayer

    International Nuclear Information System (INIS)

    Highlights: • The design idea of hybrid interlayer composed of Ni interlayer and adhesive is put forward in the paper. • The effect of Ni is strengthen by the addition of the adhesive. • The property of the Mg and Al dissimilar joint is improved by the addition of the hybrid interlayer. - Abstract: Laser-arc-adhesive hybrid welding technology is used to merge Mg to Al joints with a Ni interlayer. In this study, the effect of the adhesive on microstructure and intermetallics are analyzed. The adhesive and Ni interlayer restrain the reaction between Mg and Al. The transition zone between Mg and Al is composed of the Mg–Mg2Ni eutectic and Al–Al3Ni peritectic. The function of the Ni interlayer on the fusion zone is strengthened with the addition of the adhesive. The tensile shear test load of the laser-arc-adhesive hybrid welding of Mg to Al joints is 2.15 kN and 118 MPa without curing the adhesive. The harmful effects of the intermetallics are significantly reduced and the property of the joint is improved

  13. 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...

  14. Use of the gapped bead-on-plate test to investigate hydrogen induced cracking of flux cored arc welds of a quenched and tempered steel

    International Nuclear Information System (INIS)

    Gapped bead-on-plate (G-BOP) testing of flux cored arc welds was conducted to assess the susceptibility to hydrogen induced cold cracking (HICC) of weld metal deposited on a high strength quenched and tempered steel. For preheat temperatures higher than 40°C, no weld metal cracking was observed using a shielding gas consisting of argon with 20% carbon dioxide. In contrast, the no-crack condition was not achieved for a shielding gas consisting of argon-5% carbon dioxide for preheat temperatures lower than 100°C. This extraordinary difference in weld metal HICC resistance indicates that, in general, the shielding gas mixture can exert a major influence on weld metal transverse cold cracking behaviour

  15. Effect of the welding profile generated by the modified indirect electric arc technique on the fatigue behavior of 6061-T6 aluminum alloy

    International Nuclear Information System (INIS)

    This paper reports the effect of the welding profile generated by the modified indirect electric arc (MIEA) technique on the fatigue behavior of 6061-T6 welded joints. The calculations are based on the effect of the stress concentration factor produced by the characteristic geometry of the welding profile formed during the welding process. It was found that the fatigue life of welded samples using this welding technique was larger in comparison with data reported in the literature. Also, measurements of microhardness and tension testing were performed to account for the effect of different levels of fatigue damage on the mechanical properties of these welds. Experimental findings reveal that, with reference to undamaged samples, fatigue damage increases the microhardness in the weld metal and heat affected zone (HAZ) whereas it only produces a moderate increase in yield strength of approximately 14% for a 75% of fatigue damage. Tensile and fatigue tests indicate that the thermal affection undergone by the plates during fusion welding dictates failure in the HAZ under tension stress but not under fatigue. The failure mechanism under fatigue is discussed in terms of theoretical analyses and fractography.

  16. Annealing temperature effect on the pitting corrosion resistance of plasma arc welded joints of duplex stainless steel UNS S32304 in 1.0 M NaCl

    Energy Technology Data Exchange (ETDEWEB)

    Tan Hua [Department of Materials Science, Fudan University, Shanghai 200433 (China); Wang Zhiyu [Research and Development Center, Baosteel Co., Ltd., Shanghai 201900 (China); Jiang Yiming; Han Dong; Hong Jufeng; Chen Lindou [Department of Materials Science, Fudan University, Shanghai 200433 (China); Jiang Laizhu [Research and Development Center, Baosteel Co., Ltd., Shanghai 201900 (China); Li Jin, E-mail: corrosion@fudan.edu.c [Department of Materials Science, Fudan University, Shanghai 200433 (China)

    2011-06-15

    Highlights: {yields} Welding, heat treatment, microstructure and pitting corrosion were studied. {yields} The weakest region of DSS welded joints was determined. {yields} The optimum annealing temperature for DSS welded joints was determined. {yields} Cause of degradation and improvement of pitting corrosion was analyzed. - Abstract: Pitting corrosion resistance of 2304 duplex stainless steels after autogenous plasma-arc welding and subsequent short-time post-weld heat treatment at different temperatures, determined by critical pitting temperature in 1.0 M NaCl solution, has been investigated. The results showed that the as-welded joint displayed impaired pitting corrosion resistance and that pitting preferentially occurred at ferrite grain in heat-affected zone near the fusion line. Short-time annealing treatment at 1020-1120 {sup o}C has a beneficial effect on the pitting corrosion resistance of welded joint. The most favorable annealing temperature for the analyzed welded joints was found to be 1080 {sup o}C, at which the joint restored the pitting corrosion resistance lost during welding entirely.

  17. Analysis of effect of temperature gradients on surface-tension phenomena in gas-tungsten-arc welds

    International Nuclear Information System (INIS)

    Fluid motion directed by surface tension is considered as a contributor to heat penetration in a weld pool. The potential phenomena at the gas-liquid interface were analyzed, and the dependence of surface motion on temperature in the gas-tungsten-arc (GTA) welding process was examined. An existing heat-transfer model was used and was able to predict weld size to +- 50% of the actual value. A momentum-transfer equation was derived by considering the contribution of Lorentz force. The momentum boundary condition was developed and was able to predict the Marangoni effect. The magnitude of surface-tension-driven force is comparable to the gravitational force on one gram. An empirical approach was proposed to couple heat-transfer and momentum-transfer phenomena. A dimensional analysis identified the pertinent dimensionless groups as Reynolds, Weber, Froude, Peclet, and Power numbers and a dimensionless velocity. A simplified form of the correction was developed by combining dimensionless groups to yield a correlation with the Bond, Prandtl, and modified power numbers. Future experimental work was proposed to test the functionality of the dimensionless groups

  18. Low-Cost Open-Source Voltage and Current Monitor for Gas Metal Arc Weld 3D Printing

    Directory of Open Access Journals (Sweden)

    A. Pinar

    2015-01-01

    Full Text Available Arduino open-source microcontrollers are well known in sensor applications for scientific equipment and for controlling RepRap 3D printers. Recently low-cost open-source gas metal arc weld (GMAW RepRap 3D printers have been developed. The entry-level welders used have minimal controls and therefore lack any real-time measurement of welder voltage or current. The preliminary work on process optimization of GMAW 3D printers requires a low-cost sensor and data logger system to measure welder current and voltage. This paper reports on the development of a low-cost open-source power measurement sensor system based on Arduino architecture. The sensor system was designed, built, and tested with two entry-level MIG welders. The full bill of materials and open source designs are provided. Voltage and current were measured while making stepwise adjustments to the manual voltage setting on the welder. Three conditions were tested while welding with steel and aluminum wire on steel substrates to assess the role of electrode material, shield gas, and welding velocity. The results showed that the open source sensor circuit performed as designed and could be constructed for <$100 in components representing a significant potential value through lateral scaling and replication in the 3D printing community.

  19. Gas Metal Arc Welding Using Novel CaO-Added Mg Alloy Filler Wire

    Directory of Open Access Journals (Sweden)

    Minjung Kang

    2016-07-01

    Full Text Available Novel “ECO Mg” alloys, i.e., CaO-added Mg alloys, which exhibit oxidation resistance during melting and casting processes, even without the use of beryllium or toxic protection gases such as SF6, have recently been introduced. Research on ECO Mg alloys is still continuing, and their application as welding filler metals was investigated in this study. Mechanical and metallurgical aspects of the weldments were analysed after welding, and welding behaviours such as fume generation and droplet transfer were observed during welding. The tensile strength of welds was slightly increased by adding CaO to the filler metal, which resulted from the decreased grain size in the weld metal. When welding Mg alloys, fumes have been unavoidable so far because of the low boiling temperature of Mg. Fume reduction was successfully demonstrated with a wire composed of the novel ECO Mg filler. In addition, stable droplet transfer was observed and spatter suppression could be expected by using CaO-added Mg filler wire.

  20. Remote automatic plasma arc-closure welding of a dry-storage canister for spent nuclear fuel and high-level radioactive waste

    International Nuclear Information System (INIS)

    A carbon steel storage canister has been designed for the dry encapsulation of spent nuclear fuel assemblies or of logs of vitrified high level radioactive waste. The canister design is in conformance with the requirements of the ASME Code, Section III, Division 1 for a Class 3 vessel. The canisters will be loaded and sealed as part of a completely remote process sequence to be performed in the hot bay of an experimental encapsulation facility at the Nevada Test Site. The final closure to be made is a full penetration butt weld between the canister body, a 12.75-in O.D. x 0.25-in wall pipe, and a mating semiellipsoidal closure lid. Due to a combination of design, application and facility constraints, the closure weld must be made in the 2G position (canister vertical). The plasma arc welding system is described, and the final welding procedure is described and discussed in detail. Several aspects and results of the procedure development activity, which are of both specific and general interest, are highlighted; these include: The critical welding torch features which must be exactly controlled to permit reproducible energy input to, and gas stream interaction with, the weld puddle. A comparison of results using automatic arc voltage control with those obtained using a mechanically fixed initial arc gap. The optimization of a keyhole initiation procedure. A comparison of results using an autogenous keyhole closure procedure with those obtained using a filler metal addition. The sensitivity of the welding process and procedure to variations in joint configuration and dimensions and to variations in base metal chemistry. Finally, the advantages and disadvantages of the plasma arc process for this application are summarized from the current viewpoint, and the applicability of this process to other similar applications is briefly indicated

  1. 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

  2. Arc force self-adapt control system of invert arc welding machine%逆变弧焊机电弧推力自适应控制系统

    Institute of Scientific and Technical Information of China (English)

    朱志明; 罗小锋; 吴文楷

    2001-01-01

    When welding current is fixed,some important information such as length and section area of welding cable,connection of ground wire can be shown by output voltage of instantaneous arc-striking.The arc force self-adapt control system of invert arc welding machine is based on single-chip micro-processor MC68HC11.First,detecting the output voltage of arc-striking in the real-time,the arc force voltage can be auto-adjusted along with the ch anging of the length and section area of welding cable.Then inspecting welding v oltage in the real-time and controlling welding current by fuzzy process, there fore the arc force control of manual metal arc welding is provided with powe rful self-adaptability.%在焊接电流确定的条件下,引弧瞬间的焊机输出电压反映了焊接电缆长度、截面积以及地线连接情况等重要信息。本研究装置是基于MC68HC11单片机控制的逆变焊机电弧推力自适应控制系统,首先通过对引弧瞬间焊机输出电压的实时检测,实现了电弧推力拐点电压随焊接电流及焊接电缆长度、截面积等改变而自动调节;然后通过对焊接电弧电压的实时检测与模糊处理控制焊机的输出电流,从而使MMA手工电弧焊的电弧推力控制具有很强的自适应能力。

  3. Advantages of reduced heat input during ChopArc-welding and brazing for coated and combined metals for light weight vehicles; Vorteile des waermearmen ChopArc-Schweissens und - Loetens bei beschichteten und artverschiedenen Blechen fuer Leichtfahrzeuge

    Energy Technology Data Exchange (ETDEWEB)

    Dorn, L.; Goecke, S.F. [Inst. fuer Werkzeugmaschinen und Fabrikbetrieb, TU-Berlin (Germany)

    2001-07-01

    In conventional MAG-short-arc-welding the arc burns after ignition non-defined with continuously energy input until the next short circuit. Thereby, stochastically process fluctuations are caused by the non controlled melting of the electrode tip. In the recently developed ChopArc process, after a defined extinguishing a non arcing phase follows without any energy input until the next short circuiting on the controlled melting of the electrode tip. Hence, with the ChopArc it is possible to realize a sticky melt for thin sheet, root pass and out-of-position welding, as well as a low melt viscosity for sufficient capillary effect in MAG-brazing. (orig.) [German] Beim herkoemmlichen MAG-Kurzlichtbogen-Schweissen brennt der Lichtbogen nach seiner Zuendung bis zum naechsten Kurzschluss undefiniert mit einem kontinuierlichen Energieeintrag weiter. Aus dem dabei unkontrollierten Aufschmelzen der Elektrodenspitze resultieren stochastische Prozessschwankungen. Dagegen folgt beim neuen ChopArc-Verfahren einem gesteuerten Aufschmelzen des Elektrodendrahtes in der Brennphase mit definierter Abschaltung des Lichtbogens eine Unterbrechungsphase ohne Energieeintrag bis zum naechsten Kurzschlusseintritt. Mit dem ChopArc ist es nun moeglich, sowohl eine zaehe Schmelze fuer Duennblech-, Wurzel- oder Zwangslagenschweissen, als auch eine niedrige Schmelzbadviskositaet fuer eine gute Kapillarwirkung des Lotes beim MAG-Loeten zu erzielen. (orig.)

  4. Simulation of the Effectiveness of Dynamic Cooling for Controlling Residual Stresses in Friction Stir Welds

    OpenAIRE

    D.G. Richards, P.B. Prangnell, P.J. Withers, S.W. Williams, A. Wescott, E.C Oliver

    2008-01-01

    An FE model has been used to study the effect of localised dynamic cooling on the residual stresses developed during friction stir welding. The main aim of the work was to see if the cooling power and source positions required, to achieve significant residual stress reductions in friction stir welds, were compatible with the FSW process and recent developments in CO2 cooling systems. Comparisons were made between welds produced with a single cold spot placed over the weld line, either ahead o...

  5. Numerical modelling of hybrid arc/laser welding: a coupled approach to weld bead formation and residual stresses

    OpenAIRE

    Desmaison, Olivier; Guillemot, Gildas; Bellet, Michel

    2013-01-01

    The joining of high thickness steel sheets by means of hybrid Laser/GMAW welding processes is studied in this paper. A three dimensional finite element model has been developed to simulate this process. Through an ALE framework, a level set approach is used to model the interface between the metal and the surrounding gas. Even though the physics of the plasma is not modelled, both thermal and material supply phenomena are taken into account: (i) The laser and GMAW heat sources are simulated a...

  6. Arc welding of high strength aluminium alloys for armour systems applications

    OpenAIRE

    Pickin, Craig Graeme

    2011-01-01

    The ternary Al-Cu-Mg system 2xxx series aluminium alloys were examined as construction materials for armour system applications based upon comparable ballistic properties to the currently employed Al-7xxx series alloys. Utilising MIG welding solidification cracking was evident when welding constrained Al-2024 candidate base material using Al-2319 filler, the only available consumable wire for this series. A previously developed thermodynamic model suggested that an incompatible...

  7. A new method to estimate heat source parameters in gas metal arc welding simulation process

    International Nuclear Information System (INIS)

    Highlights: •A new method for accurate simulation of heat source parameters was presented. •The partial least-squares regression analysis was recommended in the method. •The welding experiment results verified accuracy of the proposed method. -- Abstract: Heat source parameters were usually recommended by experience in welding simulation process, which induced error in simulation results (e.g. temperature distribution and residual stress). In this paper, a new method was developed to accurately estimate heat source parameters in welding simulation. In order to reduce the simulation complexity, a sensitivity analysis of heat source parameters was carried out. The relationships between heat source parameters and welding pool characteristics (fusion width (W), penetration depth (D) and peak temperature (Tp)) were obtained with both the multiple regression analysis (MRA) and the partial least-squares regression analysis (PLSRA). Different regression models were employed in each regression method. Comparisons of both methods were performed. A welding experiment was carried out to verify the method. The results showed that both the MRA and the PLSRA were feasible and accurate for prediction of heat source parameters in welding simulation. However, the PLSRA was recommended for its advantages of requiring less simulation data

  8. 焊缝形貌对埋弧焊缝自动超声波探伤结果的影响分析%Analysis on Effect of Weld Profile on Submerged Arc Weld Automatic Ultrasonic Testing Results

    Institute of Scientific and Technical Information of China (English)

    桂光正

    2011-01-01

    The weld internal quality of double side submerged arc welding is mainly detected by automatic ultrasonic testing system. In this article, it introduced weld automatic ultrasonic testing equipment and weld tracking principle which was imported from the abroad and used in production line. Through analysis on structure of sampled pipe detected by ultrasonic testing, it explained effect factors to the accuracy of ultrasonic testing results from several aspects, such as outside weld profile, inside and outside weld width, center misalignment of inside and outside weld, anomaly weld profile resulted from edge offset, and so on. Finally, it gave measures and methods of improving ultrasonic testing accuracy for submerged arc welded pipe.%双面埋弧焊管焊缝的内部质量主要通过自动超声波探伤系统来检测.介绍了宝钢股份UOE生产线引进的管体焊缝自动超声波探伤设备及其焊缝跟踪原理.通过对该系统及超声波探伤样管结构等的分析,指出外焊缝形貌、内外焊缝宽度、内外焊缝中心偏移以及错边导致的焊缝形貌不规则等均会影响自动超声波探伤结果的准确性.最后,给出了提高埋弧焊管焊缝自动超声波探伤准确性的措施及方法.

  9. Cardiac Exposure in the Dynamic Conformal Arc Therapy, Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy of Lung Cancer

    OpenAIRE

    Xin Ming; Yuanming Feng; Huan Liu; Ying Zhang; Li Zhou; Jun Deng

    2015-01-01

    Purpose To retrospectively evaluate the cardiac exposure in three cohorts of lung cancer patients treated with dynamic conformal arc therapy (DCAT), intensity-modulated radiotherapy (IMRT), or volumetric modulated arc therapy (VMAT) at our institution in the past seven years. Methods and Materials A total of 140 lung cancer patients were included in this institutional review board approved study: 25 treated with DCAT, 70 with IMRT and 45 with VMAT. All plans were generated in a same commercia...

  10. 双丝埋弧焊焊接工艺参数对焊缝成形的影响%Study on parameters of twin-wire submerged arc welding process to impact the weld shape and quality

    Institute of Scientific and Technical Information of China (English)

    杨秀芝; 余圣甫; 姚润钢; 霍光瑞; 周强

    2011-01-01

    A detailed study of how twin-wire submerged arc welding process to impact the welding forming quality on low alloy high strength steel.The experimental results show that when welding current and voltage is certain ,double-wire with a change from two-wire serial,parallel to the staggered approach,from analysis of forming and mechanical properties of welding joint,only dual-wire submerged arc welding process of the two-wire serial is adapt to butt welding for low-alloy high-strength steel;To ensure that the joints forming quality, double-wire spacing, welding speed and welding current, voltage should be controlled within reasonable range;General ,when a high welding speed is used ,distance between pairs of wire should be selected smaller,while when welding speed is in the middle, the two-wire spacing should be controlled at the range of 20~100 mm;at the same time,welding speed should be controlled at 60~100 cm/min.The results has a certain reference value to the study of the multi-wire welding process and the welding of other types steel.%为了研究双丝埋弧焊这种高效焊接工艺对低合金高强钢焊接成形质量的影响,进行了双丝理弧焊对接试验.试验结果表明,电流、电压一定时,改变双丝排列方式从双丝串列、并列到错开方式,从接头成形和力学性能分析来看,只有双丝串列的双丝埋弧焊工艺适合低合金高强钢的时接焊接;为确保接头成形质量,双丝间距、焊接速度以及焊接电流、电压应控制在合理的范围内.采用大的焊接速度应选用较小的双丝间距,在中等焊接速度下,双丝间距应控制在20~100mm,同时焊接速度应控制在60~100cm/min.该研究结果对多丝焊工艺的研究和其他合金钢种的焊接有一定的参考价值.

  11. Observation of the mechanisms causing two kinds of undercut during laser hybrid arc welding

    Energy Technology Data Exchange (ETDEWEB)

    Karlsson, Jan, E-mail: jan.karlsson@ltu.se [Lulea University of Technology, Dept. TVM, SE-971 87 Lulea (Sweden); Norman, Peter; Kaplan, Alexander F.H. [Lulea University of Technology, Dept. TVM, SE-971 87 Lulea (Sweden); Rubin, Per [Rubin-Materialteknik, Gullhoenevaegen 13 97596 Lulea (Sweden); Lamas, Javier [Lulea University of Technology, Dept. TVM, SE-971 87 Lulea (Sweden); Centro Tecnoloxico do Naval Galego, Ferrol 15590 (A Coruna) (Spain); Yanez, Armando [Centro de Investigacions Tecnoloxicas, Universidade da Coruna, Ferrol 15403 (A Coruna) (Spain)

    2011-06-15

    Two different kinds of undercut were identified when laser hybrid welding hot rolled HSLA-steel in either the as-rolled condition or with the top surface mill scale removed. The presence of mill scale on the steel surface was found to give a sharp angled undercut combined with a sharp oxide inclusion at the edge of the weld which would have the same mechanical effect as a crack in this position. Removal of the surface oxides before welding resulted in the elimination of the oxide inclusions and a more rounded undercut geometry indicative of superior mechanical properties, particularly fatigue life. The mechanisms of the formation of both types of undercut have been analysed by high speed photography and SEM.

  12. Observation of the mechanisms causing two kinds of undercut during laser hybrid arc welding

    Science.gov (United States)

    Karlsson, Jan; Norman, Peter; Kaplan, Alexander F. H.; Rubin, Per; Lamas, Javier; Yañez, Armando

    2011-06-01

    Two different kinds of undercut were identified when laser hybrid welding hot rolled HSLA-steel in either the as-rolled condition or with the top surface mill scale removed. The presence of mill scale on the steel surface was found to give a sharp angled undercut combined with a sharp oxide inclusion at the edge of the weld which would have the same mechanical effect as a crack in this position. Removal of the surface oxides before welding resulted in the elimination of the oxide inclusions and a more rounded undercut geometry indicative of superior mechanical properties, particularly fatigue life. The mechanisms of the formation of both types of undercut have been analysed by high speed photography and SEM.

  13. SENSORING DROPLET SPRAY TRANSFER IN MIG WELDING BASED ON ARC SPECTRUM SIGNAL

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The method to detect droplet transfer by means of arc spectrum, while the experiment sets, testing principle and data processing procedure, are presented. The experiment and analysis results show that arc spectrum signal can be utilized to detect and measure the transfer procedure, the transfer modes and the transfer parameters. The arc spectrum signal enjoys excellent quality with high signal amplitude. Each transfer mode has its specific typical signal mode, and the pulse outline corresponds to an integrated transferring procedure of one droplet. All these features of arc spectrum signal can be easily applied in the control of transfer procedure,the identification and stabilization of transfer mode and the measurement of transfer parameters.

  14. A three-dimensional sharp interface model for self-consistent keyhole and weld pool dynamics in deep penetration laser welding

    Energy Technology Data Exchange (ETDEWEB)

    Pang Shengyong; Chen Liliang; Zhou Jianxin; Yin Yajun; Chen Tao, E-mail: ChenLL@mail.hust.edu.cn [State Key Laboratory of Materials Processing and Die and Mould Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2011-01-19

    A three-dimensional sharp interface model is proposed to investigate the self-consistent keyhole and weld pool dynamics in deep penetration laser welding. The coupling of three-dimensional heat transfer, fluid flow and keyhole free surface evolutions in the welding process is simulated. It is theoretically confirmed that under certain low heat input welding conditions deep penetration laser welding with a collapsing free keyhole could be obtained and the flow directions near the keyhole wall are upwards and approximately parallel to the keyhole wall. However, significantly different weld pool dynamics in a welding process with an unstable keyhole are numerically found. Many flow patterns in the welding process with an unstable keyhole, verified by x-ray transmission experiments, were successfully simulated and analysed. Periodical keyhole collapsing and bubble formation processes are also successfully simulated and believed to be in good agreement with experiments. The mechanisms of keyhole instability are found to be closely associated with the behaviour of humps on the keyhole wall, and it is found that the welding speed and surface tension are closely related to the formation of humps on the keyhole wall. It is also shown that the weld pool dynamics in laser welding with an unstable keyhole are closely associated with the transient keyhole instability and therefore modelling keyhole and weld pool in a self-consistent way is significant to understand the physics of laser welding.

  15. A three-dimensional sharp interface model for self-consistent keyhole and weld pool dynamics in deep penetration laser welding

    International Nuclear Information System (INIS)

    A three-dimensional sharp interface model is proposed to investigate the self-consistent keyhole and weld pool dynamics in deep penetration laser welding. The coupling of three-dimensional heat transfer, fluid flow and keyhole free surface evolutions in the welding process is simulated. It is theoretically confirmed that under certain low heat input welding conditions deep penetration laser welding with a collapsing free keyhole could be obtained and the flow directions near the keyhole wall are upwards and approximately parallel to the keyhole wall. However, significantly different weld pool dynamics in a welding process with an unstable keyhole are numerically found. Many flow patterns in the welding process with an unstable keyhole, verified by x-ray transmission experiments, were successfully simulated and analysed. Periodical keyhole collapsing and bubble formation processes are also successfully simulated and believed to be in good agreement with experiments. The mechanisms of keyhole instability are found to be closely associated with the behaviour of humps on the keyhole wall, and it is found that the welding speed and surface tension are closely related to the formation of humps on the keyhole wall. It is also shown that the weld pool dynamics in laser welding with an unstable keyhole are closely associated with the transient keyhole instability and therefore modelling keyhole and weld pool in a self-consistent way is significant to understand the physics of laser welding.

  16. Spectroscopic analysis of the plasma continuum radiation for on-line arc-welding defect detection

    International Nuclear Information System (INIS)

    When plasma optical spectroscopy is applied to on-line welding quality monitoring, the plasma electronic temperature is commonly selected as the spectroscopic parameter to determine. However, several processing stages have to be considered in this case, including plasma emission line identification, which is significantly costly in terms of computational performance. In this paper, the wavelength associated with the maximum intensity of the plasma background emission is proposed as the new monitoring signal, as it will be demonstrated that there is a clear correlation between this parameter and the welding quality. The resulting processing scheme is clearly simpler, and experimental and field tests will prove the feasibility of the proposed technique

  17. 直缝埋弧焊管生产线焊接车输送系统的改进%Improvement of Welding Carriage Transport System in Longitudinal Submerged Arc Welded (SAWL) Pipe

    Institute of Scientific and Technical Information of China (English)

    施俊杰; 耿亮; 王占理; 徐刚; 刘增强; 李建忠

    2014-01-01

    直缝埋弧焊管生产线内外焊机组在焊接过程中会产生断弧烧穿缺陷,其主要原因为焊接车卡阻爬行和预焊及预焊修补焊缝浅等。分析了焊接车卡阻爬行的原因,并采取了相应的改进措施,即分别对焊接车道轨与横移车道轨、焊接车车体以及横移车减速机等进行了改造。改造后的实际使用结果表明,此次对焊接车输送系统的改造不仅直接降低了断弧烧穿缺陷的产生概率,而且使焊速更为稳定,也减少了咬边、夹渣等缺陷的出现几率。%The arc breaking burn through defects may generate in inside and outside unit of SAWL pipe production line, the main causes are welding carriage crawling, pre-welding and repair welding shallow for weld etc. In this article, it analyzed the reason of crawling, and adopted according improvement measures, that is conducting transform for welding carriage tracks, transverse carriage tracks, welding carriage body and reducer of transverse carriage. The modified actual use results showed that transportation system transform of welding carriage not only reduced probability of arc breaking burn through, but also decreased appear probability of undercut, slag inclusion etc., as well as welding speed more stable.

  18. 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...

  19. Factors Affecting the Capture Efficiency of a Fume Extraction Torch for Gas Metal Arc Welding.

    Science.gov (United States)

    Bonthoux, Francis

    2016-07-01

    Welding fumes are classified as Group 2B 'possibly carcinogenic' and this prompts to the implementation of local exhaust ventilation (LEV). The fume extraction torch with LEV integrated into the tool is the most attractive solution but its capture efficiency is often disappointing in practice. This study assesses the main parameters affecting fume capture efficiency namely the extraction flow rate, the positioning of the suction openings on the torch, the angle of inclination of the torch to the workpiece during welding, the metal transfer modes, and the welding deposition rate. The theoretical velocity induced by suction, estimated from the extraction flow rate and the position of the suction openings, is the main parameter affecting effectiveness of the device. This is the design parameter and its value should never be Welding with high deposition rates (>1.1g s(-1)) and spray transfer leads to low capture efficiency if induced velocities are <0.5 m s(-1) The results of the study can be used in the design of integrated on-torch extraction systems and provide information for fixing system objectives. PMID:27074798

  20. Microstructures and mechanical properties of Gas Tungsten Arc Welded joints of new Al–Mg–Sc and Al–Mg–Er alloy plates

    International Nuclear Information System (INIS)

    The effect of microalloy element Sc and Er on Gas Tungsten Arc Welded (GTAW) joints of Al–Mg alloy was studied by comparative method. The microstructures and mechanical properties of Al–Mg–Sc and Al–Mg–Er alloy welded joint were examined by microhardness measurement, tensile test, optical microscopy and transmission electron microscope. The strength of Al–Mg–Sc welded joint is higher than that of Al–Mg–Er welded joint. The differences of the two welded joints can be attributed to the different thermal stability and the effect of Al3(Sc1−x,Zrx) particles and Al3(Er1−x,Zrx) particles. Al3(Sc1−x,Zrx) particles, which have higher thermal stability, are still coherent with Al matrix in the HAZ, can strongly pin dislocations and subgrain boundaries of the HAZ. There are strain strengthening and precipitation strengthening in the HAZ of Al–Mg–Sc welded joints. Notable coarsening of Al3(Er1−x,Zrx) particles and recrystallization in the HAZ of Al–Mg–Er welded joint lead to the reduction and disappearance of strain strengthening and precipitation strengthening

  1. Microstructures and mechanical properties of Gas Tungsten Arc Welded joints of new Al–Mg–Sc and Al–Mg–Er alloy plates

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Le [Key Laboratory of Super-Microstructure and Ultrafast Process in Advanced Materials of Hunan Province, School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China); Peng, Yongyi, E-mail: pengyongyi@126.com [Key Laboratory of Super-Microstructure and Ultrafast Process in Advanced Materials of Hunan Province, School of Physics and Electronics, Central South University, Changsha, Hunan 410083 (China); Huang, Jiwu; Deng, Ying; Yin, Zhimin [School of Materials Science and Engineering, Central South University, Changsha, Hunan 410083 (China)

    2015-01-03

    The effect of microalloy element Sc and Er on Gas Tungsten Arc Welded (GTAW) joints of Al–Mg alloy was studied by comparative method. The microstructures and mechanical properties of Al–Mg–Sc and Al–Mg–Er alloy welded joint were examined by microhardness measurement, tensile test, optical microscopy and transmission electron microscope. The strength of Al–Mg–Sc welded joint is higher than that of Al–Mg–Er welded joint. The differences of the two welded joints can be attributed to the different thermal stability and the effect of Al{sub 3}(Sc{sub 1−x},Zr{sub x}) particles and Al{sub 3}(Er{sub 1−x},Zr{sub x}) particles. Al{sub 3}(Sc{sub 1−x},Zr{sub x}) particles, which have higher thermal stability, are still coherent with Al matrix in the HAZ, can strongly pin dislocations and subgrain boundaries of the HAZ. There are strain strengthening and precipitation strengthening in the HAZ of Al–Mg–Sc welded joints. Notable coarsening of Al{sub 3}(Er{sub 1−x},Zr{sub x}) particles and recrystallization in the HAZ of Al–Mg–Er welded joint lead to the reduction and disappearance of strain strengthening and precipitation strengthening.

  2. 38: Optimization of electron arc therapy doses by dynamic collimator control

    International Nuclear Information System (INIS)

    The problem of delivering a uniform dose to a large curved surface such as a patient's chest wall has been addressed by the technique of electron arc therapy. Prospective computer simulations show that a dramatic improvement in dose uniformity can, in many clinical situations, be achieved by dynamic shaping of the electron arc collimator, under computer control, as a function of gantry angle and distance superior or inferior to the central plane. Computer optimization techniques applied to the design of a multivane dynamic electron arc collimator is presented, along with representative treatment plans resulting from inclusion of this dynamic technique in electron arc therapy. 17 refs.; 5 figs

  3. Relation between biomarkers in exhaled breath condensate and internal exposure to metals from gas metal arc welding.

    Science.gov (United States)

    Hoffmeyer, Frank; Raulf-Heimsoth, Monika; Weiss, Tobias; Lehnert, Martin; Gawrych, Katarzyna; Kendzia, Benjamin; Harth, Volker; Henry, Jana; Pesch, Beate; Brüning, Thomas

    2012-06-01

    Concerning possible harmful components of welding fumes, besides gases and quantitative aspects of the respirable welding fumes, particle-inherent metal toxicity has to be considered.The objective of this study was to investigate the effect markers leukotriene B4 (LTB4),prostaglandin E2 (PGE2) and 8-isoprostane (8-Iso PGF2α) as well as the acid–base balance(pH) in exhaled breath condensate (EBC) of 43 full-time gas metal arc welders (20 smokers) in relation to welding fume exposure. We observed different patterns of iron, chromium and nickel in respirable welding fumes and EBC. Welders with undetectable chromium in EBC(group A, n = 24) presented high iron and nickel concentrations. In this group, higher 8-isoPGF2α and LTB4 concentrations could be revealed compared to welders with detectable chromium and low levels of both iron and nickel in EBC (group B): 8-iso PGF2α443.3 pg mL−1 versus 247.2 pg mL−1; p = 0.001 and LTB4 30.5 pg mL−1 versus 17.3 pgmL−1; p = 0.016. EBC-pH was more acid in samples of group B (6.52 versus 6.82; p = 0.011).Overall, effect markers in welders were associated with iron concentrations in EBC according to smoking habits--non-smokers/smokers: LTB4 (rs = 0.48; p = 0.02/rs = 0.21; p = 0.37),PGE2 (rs = 0.15; p = 0.59/rs = 0.47; p = 0.07), 8-iso PGF2α (rs = 0.18; p = 0.54/rs = 0.59;p = 0.06). Sampling of EBC in occupational research provides a matrix for the simultaneous monitoring of metal exposure and effects on target level. Our results suggest irritative effects in the airways of healthy welders. Further studies are necessary to assess whether these individual results might be used to identify welders at elevated risk for developing a respiratory disease. PMID:22622358

  4. Estimation of dynamic properties of attractors observed in hollow copper electrode atmospheric pressure arc plasma system

    Indian Academy of Sciences (India)

    S Ghorul; S N Sahasrabudhe; P S S Murthy; A K Das; N Venkatramani

    2002-07-01

    Understanding of the basic nature of arc root fluctuation is still one of the unsolved problems in thermal arc plasma physics. It has direct impact on myriads of thermal plasma applications being implemented at present. Recently, chaotic nature of arc root behavior has been reported through the analysis of voltages, acoustic and optical signals which are generated from a hollow copper electrode arc plasma torch. In this paper we present details of computations involved in the estimation process of various dynamic properties and show how they reflect chaotic behavior of arc root in the system.

  5. Dry Hyperbaric Gas Metal Arc Welding of Subsea Pipelines : Experiments and Modeling

    OpenAIRE

    Azar, Amin S.

    2012-01-01

    Ambitions in exploration of oil and gas fields at deeper water depth require continuous investigation and maintenance. The transportation pipelines laid in deep waters are both subjected to corrosion and buckling due to environmental phenomena. They may also often undergo branching (namely hot tapping) to redirect (or add to) the transportation paths. Mechanical joints and welding are both considered as available alternatives when sectioning and replacement of the pipes at shallow waters is n...

  6. Stress corrosion cracking behaviour of gas tungsten arc welded super austenitic stainless steel joints

    OpenAIRE

    M. Vinoth Kumar; Balasubramanian, V.; S. RAJAKUMAR; Shaju K. Albert

    2015-01-01

    Super 304H austenitic stainless steel with 3% of copper posses excellent creep strength and corrosion resistance, which is mainly used in heat exchanger tubing of the boiler. Heat exchangers are used in nuclear power plants and marine vehicles which are intended to operate in chloride rich offshore environment. Chloride stress corrosion cracking is the most likely life limiting failure with austenitic stainless steel tubing. Welding may worsen the stress corrosion cracking susceptibility of t...

  7. Direct Observations of Austenite, Bainite and Martensite Formation During Arc Welding of 1045 Steel using Time Resolved X-Ray Diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Elmer, J; Palmer, T; Babu, S; Zhang, W; DebRoy, T

    2004-02-17

    In-situ Time Resolved X-Ray Diffraction (TRXRD) experiments were performed during stationary gas tungsten arc (GTA) welding of AISI 1045 C-Mn steel. These synchrotron-based experiments tracked, in real time, phase transformations in the heat-affected zone of the weld under rapid heating and cooling conditions. The diffraction patterns were recorded at 100 ms intervals, and were later analyzed using diffraction peak profile analysis to determine the relative fraction of ferrite ({alpha}) and austenite ({gamma}) phases in each diffraction pattern. Lattice parameters and diffraction peak widths were also measured throughout the heating and cooling cycle of the weld, providing additional information about the phases that were formed. The experimental results were coupled with a thermofluid weld model to calculate the weld temperatures, allowing time-temperature transformation kinetics of the {alpha} {yields} {gamma} phase transformation to be evaluated. During heating, complete austenitization was observed in the heat affected zone of the weld and the kinetics of the {alpha} {yields} {gamma} phase transformation were modeled using a Johnson-Mehl-Avrami (JMA) approach. The results from the 1045 steel weld were compared to those of a 1005 low carbon steel from a previous study. Differences in austenitization rates of the two steels were attributed to differences in the base metal microstructures, particularly the relative amounts of pearlite and the extent of the allotriomorphic ferrite phase. During weld cooling, the austenite transformed to a mixture of bainite and martensite. In situ diffraction was able to distinguish between these two non-equilibrium phases based on differences in their lattice parameters and their transformation rates, resulting in the first real time x-ray diffraction observations of bainite and martensite formation made during welding.

  8. 3D transient multiphase model for keyhole, vapor plume, and weld pool dynamics in laser welding including the ambient pressure effect

    Science.gov (United States)

    Pang, Shengyong; Chen, Xin; Zhou, Jianxin; Shao, Xinyu; Wang, Chunming

    2015-11-01

    The physical process of deep penetration laser welding involves complex, self-consistent multiphase keyhole, metallic vapor plume, and weld pool dynamics. Currently, efforts are still needed to understand these multiphase dynamics. In this paper, a novel 3D transient multiphase model capable of describing a self-consistent keyhole, metallic vapor plume in the keyhole, and weld pool dynamics in deep penetration fiber laser welding is proposed. Major physical factors of the welding process, such as recoil pressure, surface tension, Marangoni shear stress, Fresnel absorptions mechanisms, heat transfer, and fluid flow in weld pool, keyhole free surface evolutions and solid-liquid-vapor three phase transformations are coupling considered. The effect of ambient pressure in laser welding is rigorously treated using an improved recoil pressure model. The predicated weld bead dimensions, transient keyhole instability, weld pool dynamics, and vapor plume dynamics are compared with experimental and literature results, and good agreements are obtained. The predicted results are investigated by not considering the effects of the ambient pressure. It is found that by not considering the effects of ambient pressure, the average keyhole wall temperature is underestimated about 500 K; besides, the average speed of metallic vapor will be significantly overestimated. The ambient pressure is an essential physical factor for a comprehensive understanding the dynamics of deep penetration laser welding.

  9. Narrow gap mechanised arc welding in nuclear components manufactured by AREVA NP; Le soudage mecanise a l'arc en chanfrein etroit dans les constructions nucleaires realisees par AREVA NP

    Energy Technology Data Exchange (ETDEWEB)

    Peigney, A. [Departement Soudage AREVA Centre Technique - 71380 Saint-Marcel (France)

    2007-07-01

    Nuclear components require welds of irreproachable and reproducible quality. Moreover, for a given welding process, productivity requirements lead to reduce the volume of deposited metal and thus to use narrow gap design. In the shop, narrow gap Submerged Arc Welding process (SAW) is currently used on rotating parts in flat position for thicknesses up to 300 mm. Welding is performed with one or two wires in two passes per layer. In Gas Tungsten Arc Welding process (GTAW), multiple applications can be found because this process presents the advantage of allowing welding in all positions. Welding is performed in one or two passes per layer. The process is used in factory and on the nuclear sites for assembling new components but also for replacing components and for repairs. Presently, an increase of productivity of the process is sought through the use of hot wire and/or two wires. Concerning Gas Metal Arc Welding process (GMAW), its use is growing for nuclear components, including narrow gap applications. This process, limited in its applications in the past on account of the defects it generated, draws benefit from the progress of the welding generators. Then it is possible to use this efficient process for high security components such as those of nuclear systems. It is to be noted that the process is applicable in the various welding positions as it is the case for GTAW, while being more efficient than the latter. This paper presents the state of the art in the use of narrow gap mechanised arc welding processes by AREVA NP units. (author) [French] Les constructions nucleaires necessitent des soudures de qualite irreprochable et reproductible. Par ailleurs les imperatifs de productivite conduisent, pour un procede donne, a reduire le volume de metal a deposer et donc a utiliser des chanfreins etroits. En atelier, le soudage fil-flux en chanfrein etroit est couramment utilise sur des pieces tournantes en position a plat pour des epaisseurs atteignant 300 mm. On

  10. Computer Control of Weld Shape for Helical Submerged-arc Welding (SAW) Pipe%螺旋埋弧焊管焊缝形状的计算机控制

    Institute of Scientific and Technical Information of China (English)

    高锋; 王高峰; 高聪

    2015-01-01

    In order to further improve the weld shape of SAWH pipe and welding quality, it analyzed 5 process measures affecting SAWH pipe weld shape control in this article, and set up mathematical model of the weld shape curve. It used VB language to establish the module of the description of the welded joint shape, described weld shape subsection, obtained the fitted equation, and set up weld shape evaluation system. It utilized database system and expert system to optimize welding parameter, and select the most reasonable and the most ideal welding scheme, finally realized the weld shape improvement and welding quality enhancement. The database system of weld shape control and expert system can also be used for on-site submerged arc welding process optimization.%为进一步改进埋弧焊焊缝形状及提高焊接质量,分析了影响埋弧焊焊缝形状控制的五个工艺措施,建立了焊缝形状曲线的数学模型,利用VB语言编制描述焊缝形状的模块,对焊缝形状分段描述并得到描述的拟合方程,再建立焊缝形状评价系统,对拟合效果及焊缝形状进行评价,最后利用数据库系统和专家系统,进行焊接参数优化,选出最合理、最理想的焊接方案,最终实现焊缝形状的改进和焊接质量的提高。焊缝形状控制数据库系统和专家系统还可用于现场埋弧焊焊接工艺的优化。

  11. Effect of Welding Mateial on Mechanical Working Properity of Gay Cast-iron by Cold Arc Welding%灰铸铁电弧冷焊时焊材对加工性能的影响

    Institute of Scientific and Technical Information of China (English)

    李日娟

    2011-01-01

    采用Z208、Z248、Z308、Z116四种焊条对灰铸铁进行电弧冷焊试验,对比了焊缝组织、半熔化区白口硬度及宽度,并从焊接冶金角度作出分析.结果表明:Z208 、Z248所焊焊缝同母材一样为灰铸铁,Z208因白口宽度大不能进行后续机加工;Z308、Z116所焊焊缝与母材异质,Z308几乎无白口,具有优良的加工性能.%The welding tests on Gay cast-iron were made with four kinds of electrode by cold arc welding(Z208 Z248 Z308 Zl 16), metallographic microstructure, the width and microhardness of the partial fusion were compared in welding metallurgy. The results show that the welded joint by Z208 and Z248 is same with base metal, the welded joint by Z208 are not matched; the welded joint by Z308 and Zl 16 is not same with the base metal, but the machining property is better.

  12. Influence of Mode of Metal Transfer on Microstructure and Mechanical Properties of Gas Metal Arc-Welded Modified Ferritic Stainless Steel

    Science.gov (United States)

    Mukherjee, Manidipto; Pal, Tapan Kumar

    2012-06-01

    This article describes in detail the effect of the modes of metal transfer on the microstructure and mechanical properties of gas metal arc-welded modified ferritic stainless steel (SSP 409M) sheets (as received) of 4 mm thickness. The welded joints were prepared under three modes of metal transfer, i.e., short-circuit (SC), spray (S), transfer, and mix (M) mode transfer using two different austenitic filler wires (308L and 316L) and shielding gas composition of Ar + 5 pct CO2. The welded joints were evaluated by means of microstructural, hardness, notched tensile strength, Charpy impact toughness, and high cycle fatigue. The dependence of weld metal microstructure on modes of metal transfer and filler wires has been determined by dilution calculation, WRC-1992 diagram, Creq/Nieq ratio, stacking fault energy (SFE), optical microscopy (OM), and transmission electron microscopy (TEM). It was observed that the microstructure as well as the tensile, Charpy impact, and high cycle fatigue of weld metal is significantly affected by the mode of metal transfer and filler wire used. However, the heat-affected zone (HAZ) is affected only by the modes of metal transfer. The results have been correlated with the microstructures of weld and HAZ developed under different modes of metal transfer.

  13. Characterization of Mg/Al butt joints welded by gas tungsten arc filling with Zn–29.5Al–0.5Ti filler metal

    International Nuclear Information System (INIS)

    The multivariate alloying design of a welding joint is used in the Mg to Al welding process. A Zn–29.5Al–0.5Ti alloy is added as filler metal in gas tungsten arc welding of Mg and Al alloy joint based on the analysis of Al and Mg alloy characteristics. The tensile strength, microstructure, and phase constitution of the weld seam are analyzed. The formation of brittle and hard Mg–Al intermetallic compounds is avoided because of the effects of Zn, Al, and Ti. The average tensile strength of the joint is 148 MPa. Al3Ti is first precipitated and functions as the nucleus of heterogeneous nucleation during solidification. Moreover, the precipitated Al–MgZn2 hypoeutectic phase exhibited a feather-like structure, which enhances the property of the Mg–Al dissimilar joint. - Highlights: • Mg alloy AZ31B and Al alloy 6061 are butt welded by fusion welding. • The effect of Ti in filler metal is investigated. • The formation of Mg–Al intermetallic compounds is avoided

  14. Optimization of Process Parameters to Minimize Angular Distortion in Gas Tungsten Arc Welded Stainless Steel 202 Grade Plates Using Genetic Algorithms

    Directory of Open Access Journals (Sweden)

    Sudhakaran .R,

    2010-05-01

    Full Text Available This paper presents a study on optimization of process parameters using genetic algorithm to minimize angular distortion in 202 grade stainless steel gas tungsten arc welded plates. Angular distortion is a major problem and most pronounced among different types of distortion in butt welded plates. The extent of distortion depends onthe welding process control parameters. The important process control parameters chosen for study are gun angle (θ, welding speed (V, plate length (L, welding current (I and gas flow rate (Q. The experiments are conducted based on five factor five level central composite rotatable designs with full replication technique. A mathematical model was developed correlating the process parameters and the angular distortion. The developed model is checked for the adequacy based on ANOVA analysis and accuracy of prediction by confirmatory test. The optimization of process parameters was done using genetic algorithms (GA. A source code was developed using C language to do the optimization. The optimal process parameters gave a value of 0.000379° for angular distortion which demonstrates the accuracy and effectiveness of the model presented and program developed. The obtained results indicate that the optimized parameters are capable of producing weld with minimum distortion.

  15. STUDY ON THE PRESSURE IN PLASMA ARC

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The axial pressure in plasma arc is measured under different conditions. The effects of the parameters, such as welding current, plasma gas flow rate, electrode setback and arc length, on the pressure in plasma arc are investigated and quantitative analyzed to explain the relationship between the quality of weld and the matching of parameters in plasma arc welding process.

  16. Commissioning and quality assurance of Dynamic WaveArc irradiation.

    Science.gov (United States)

    Sato, Sayaka; Miyabe, Yuki; Takahashi, Kunio; Yamada, Masahiro; Nakamura, Mitsuhiro; Ishihara, Yoshitomo; Yokota, Kenji; Kaneko, Shuji; Mizowaki, Takashi; Monzen, Hajime; Hiraoka, Masahiro

    2015-01-01

    A novel three-dimensional unicursal irradiation technique "Dynamic WaveArc" (DWA), which employs simultaneous and continuous gantry and O-ring rotation during dose delivery, has been implemented in Vero4DRT. The purposes of this study were to develop a commissioning and quality assurance procedure for DWA irradiation, and to assess the accuracy of the mechanical motion and dosimetric control of Vero4DRT. To determine the mechanical accuracy and the dose accuracy with DWA irradiation, 21 verification test patterns with various gantry and ring rotational directions and speeds were generated. These patterns were irradiated while recording the irradiation log data. The differences in gantry position, ring position, and accumulated MU (EG, ER, and EMU, respectively) between the planned and actual values in the log at each time point were evaluated. Furthermore, the doses delivered were measured using an ionization chamber and spherical phantom. The constancy of radiation output during DWA irradiation was examined by comparison with static beam irradiation. The mean absolute error (MAE) of EG and ER were within 0.1° and the maximum error was within 0.2°. The MAE of EMU was within 0.7 MU, and maximum error was 2.7 MU. Errors of accumulated MU were observed only around control points, changing gantry, and ring velocity. The gantry rotational range, in which EMU was greater than or equal to 2.0 MU, was not greater than 3.2%. It was confirmed that the extent of the large differences in accumulated MU was negligibly small during the entire irradiation range. The variation of relative output value for DWA irradiation was within 0.2%, and this was equivalent to conventional arc irradiation with a rotating gantry. In conclusion, a verification procedure for DWA irradiation was designed and implemented. The results demonstrated that Vero4DRT has adequate mechanical accuracy and beam output constancy during gantry and ring rotation. PMID:26103177

  17. Short-cycle drawn arc stud welding applications%短周期拉弧式螺柱焊的应用

    Institute of Scientific and Technical Information of China (English)

    何琪; 刘晓锋

    2014-01-01

    对影响短周期拉弧式螺柱焊焊接质量的几项因素进行分析,结合车身焊装车间两种常用螺柱焊接产品,归纳总结几项主要参数调整规范及两种焊接产品的优劣。%On the impact of short-cycle drawn arc stud welding quality analysis of several factors, combined with the two body assembly plant commonly stud welding products, summarizes several key parameters to adjust the specifications and the pros and cons of two welding products.

  18. Short-cycle drawn arc stud welding applications%短周期拉弧式螺柱焊的应用

    Institute of Scientific and Technical Information of China (English)

    何琪; 刘晓锋

    2014-01-01

    On the impact of short-cycle drawn arc stud welding quality analysis of several factors, combined with the two body assembly plant commonly stud welding products, summarizes several key parameters to adjust the specifications and the pros and cons of two welding products.%对影响短周期拉弧式螺柱焊焊接质量的几项因素进行分析,结合车身焊装车间两种常用螺柱焊接产品,归纳总结几项主要参数调整规范及两种焊接产品的优劣。

  19. Analysis of Digital Control Technology of Inverter Arc Welding Power Supply%弧焊逆变电源的数字化控制技术分析

    Institute of Scientific and Technical Information of China (English)

    崔爱玲

    2015-01-01

    This paper discusses the characteristics and operating principle of digital-controlled inverter arc welding power supply,analyzes digital control technology of inverter arc welding power supply using TMS320LF2407 as the con-troller,and finally presents related hardware and software design.With the establishment of informationalized and digital platform,higher performance of inverter arc welding power supply is achieved.%论述了数字化弧焊电源系统的特征及弧焊逆变电源的工作原理,分析了以 TMS320LF2407为控制核心的弧焊逆变电源的数字化控制技术,给出了其数字化控制的硬件设计和软件设计。通过弧焊逆变电源的信息化、数字化平台的建立,实现了弧焊逆变电源更高性能的应用。

  20. Microstructure and abrasive wear properties of M(Cr,Fe7C3 carbides reinforced high-chromium carbon coating produced by gas tungsten arc welding (GTAW process

    Directory of Open Access Journals (Sweden)

    Soner BUYTOZ

    2010-01-01

    Full Text Available In the present study, high-chromium ferrochromium carbon hypereutectic alloy powder was coated on AISI 4340 steel by the gas tungsten arc welding (GTAW process. The coating layers were analyzed by optical microscopy, X-ray diffraction (XRD, field-emission scanning electron microscopy (FE-SEM, X-ray energy-dispersive spectroscopy (EDS. Depending on the gas tungsten arc welding pa-rameters, either hypoeutectic or hypereutectic microstructures were produced. Wear tests of the coatings were carried out on a pin-on-disc apparatus as function of contact load. Wear rates of the all coating layers were decreased as a function of the loading. The improvement of abrasive wear resistance of the coating layer could be attributed to the high hardness of the hypereutectic M7C3 carbides in the microstruc-ture. As a result, the microstructure of surface layers, hardness and abrasive wear behaviours showed different characteristics due to the gas tungsten arc welding parameters.

  1. Study of Dynamic Features of Surface Plasma in High-Power Disk Laser Welding

    Science.gov (United States)

    Wang, Teng; Gao, Xiangdong; Katayama, Seiji; Jin, Xiaoli

    2012-03-01

    High-speed photography was used to obtain the dynamic changes in the surface plasma during a high-power disk laser welding process. A color space clustering algorithm to extract the edge information of the surface plasma region was developed in order to improve the accuracy of image processing. With a comparative analysis of the plasma features, i.e., area and height, and the characteristics of the welded seam, the relationship between the surface plasma and the stability of the laser welding process was characterized, which provides a basic understanding for the real-time monitoring of laser welding.

  2. Study of Dynamic Features of Surface Plasma in High-Power Disk Laser Welding

    Institute of Scientific and Technical Information of China (English)

    王腾; 高向东; Katayatna SEIJI; 金小莉

    2012-01-01

    High-speed photography was used to obtain the dynamic changes in the surface plasma during a high-power disk laser welding process. A color space clustering algorithm to extract the edge information of the surface plasma region was developed in order to improve the accuracy of image processing. With a comparative analysis of the plasma features, i.e., area and height, and the characteristics of the welded seam, the relationship between the surface plasma and the stability of the laser welding process was characterized, which provides a basic understanding for the real-time monitoring of laser welding.

  3. Study of Dynamic Features of Surface Plasma in High-Power Disk Laser Welding

    International Nuclear Information System (INIS)

    High-speed photography was used to obtain the dynamic changes in the surface plasma during a high-power disk laser welding process. A color space clustering algorithm to extract the edge information of the surface plasma region was developed in order to improve the accuracy of image processing. With a comparative analysis of the plasma features, i.e., area and height, and the characteristics of the welded seam, the relationship between the surface plasma and the stability of the laser welding process was characterized, which provides a basic understanding for the real-time monitoring of laser welding.

  4. 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…

  5. Dynamics of keyhole and molten pool in high-power CO2 laser welding

    Science.gov (United States)

    Matsunawa, Akira; Seto, Naoki; Kim, Jong-Do; Mizutani, Masami; Katayama, Seiji

    2000-02-01

    A deep cavity called keyhole is formed in the laser weld pool due to the intense recoil pressure of evaporation. The formation of keyhole leads to a deep penetration weld with high aspect ratio. However, a hole drilled in a liquid pool is primarily unstable by its nature and the instability of keyhole also causes the formation of porosity in the weld metal. The porosity formation is one of the serious problems in the very high power laser welding, but its mechanism has not been well understood. The authors have conducted systematic studies on observation of keyhole as well as weld pool dynamics and their related phenomena to reveal the mechanism of porosity formation and its suppression methods. The paper describes the real time observation of keyhole and laser plasma/plume behaviors in the high power CW CO2 laser welding by the high speed optical and X-ray transmission methods, cavity formation process and its suppression measures.

  6. Determination of Informal Sector as Urban Pollution Source : Fume Characterization of Small-scale Manual Metal Arc Welding using Factor Analysis in Bandung City

    Directory of Open Access Journals (Sweden)

    A. Nastiti

    2012-04-01

    Full Text Available In developing countries, the informal sector, particularly small-scale welding activities, are considered to be an important contributor to urban air pollution although studies in this sector are limited. This study aims to identify the composition of small-scale welding fume in order to further investigate the effects and set control strategies and urban pollution abatement policies. Breathing zone air samples were collected from 30 mild steel manual metal arc welders and 17 non-welders in Bandung City, West Java, Indonesia. The respirable particulates in air samples were analyzed using gravimetric method, and Instrumental Neutron Activation Analysis (INAA was employed to identify characteristic of welding fume. It was found that respirable particulates concentration in welders (range : 315.6 and 3,735.93 µgm-3; average 1,545.436 µgm-3 were significantly higher than in non-welders (range : 41.84 and 1,688.03 µgm-3; average : 375.783 µgm-3. Welders’ breathing zones contain Fe>Na>K>Mn>Al >Cr>Ti>Cl>Br>I>Zn>Sb>V>Co>Sc; while non-welders’ breathing zones contain Cr>F>Al>Ti>Na>Br>I>Mn>Cl>Co>Zn>Sc. Inter-species correlation analysis conducted using Statgraphic Ver. 4.0 shows that Fe (range : n.d. – 775.19 µgm-3; average: 0.1674 µgm-3, Co (range : n.d. – 0.51 µgm-3; average: 0.000082 µgm-3, Mn (range : 0.39 – 148.37 µgm-3; average: 0.0374 µgm-3, Na (range: 0.17 and 623.85 µgm-3; average: 0.0973 µgm-3 and K (range : n.d. – 301.15 µgm-3; average: 0.0535 µgm-3 were emitted from welding activity, and thus are considered as components of welding fume which contribute to urban air pollution. Although welding fume and the identified species in welding fume were still below permissible limit, small-scale welding activities have great potential in emitting higher fume concentration due to due to high variability of welding activities, such as welding frequency, materials being welded, and varied environmental conditions

  7. Determination of Informal Sector as Urban Pollution Source : Fume Characterization of Small-scale Manual Metal Arc Welding using Factor Analysis in Bandung City

    International Nuclear Information System (INIS)

    In developing countries, the informal sector, particularly small-scale welding activities, are considered to be an important contributor to urban air pollution although studies in this sector are limited. This study aims to identify the composition of small-scale welding fume in order to further investigate the effects and set control strategies and urban pollution abatement policies. Breathing zone air samples were collected from 30 mild steel manual metal arc welders and 17 non-welders in Bandung City, West Java, Indonesia. The respirable particulates in air samples were analyzed using gravimetric method, and Instrumental Neutron Activation Analysis (INAA) was employed to identify characteristic of welding fume. It was found that respirable particulates concentration in welders (range : 315.6 and 3,735.93 µgm-3; average 1,545.436 µgm-3) were significantly higher than in non-welders (range : 41.84 and 1,688.03 µgm-3; average : 375.783 µgm-3). Welders' breathing zones contain Fe>Na>K>Mn>Al >Cr>Ti>Cl>Br>I>Zn>Sb>V>Co>Sc; while non-welders' breathing zones contain Cr>F>Al>Ti>Na>Br>I>Mn>Cl>Co>Zn>Sc. Inter-species correlation analysis conducted using Statgraphic Ver. 4.0 shows that Fe (range : n.d. - 775.19 µgm-3; average: 0.1674µgm-3), Co (range : n.d. - 0.51 µgm-3; average: 0.000082 µgm-3), Mn (range : 0.39 - 148.37 µgm-3; average: 0.0374 µgm-3), Na (range: 0.17 and 623.85 µgm-3; average: 0.0973 µgm-3) and K (range : n.d. - 301.15 µgm-3; average: 0.0535 µgm-3) were emitted from welding activity, and thus are considered as components of welding fume which contribute to urban air pollution. Although welding fume and the identified species in welding fume were still below permissible limit, small-scale welding activities have great potential in emitting higher fume concentration due to due to high variability of welding activities, such as welding frequency, materials being welded, and varied environmental conditions. (author)

  8. Reasons for superior mechanical and corrosion properties of 2219 aluminum alloy electron beam welds

    International Nuclear Information System (INIS)

    Electron beam welds of aluminum alloy 2219 offer much higher strength compared to gas tungsten arc welds of the same alloy and the reasons for this have not been fully explored. In this study both types of welds were made and mechanical properties were evaluated by tensile testing and pitting corrosion resistance by potentio dynamic polarization tests. It is shown that electron beam welds exhibit superior mechanical and corrosion properties. The weld metals have been characterized by scanning electron microscopy; transmission electron microscopy and electron probe micro analysis. Presence of partially disintegrated precipitates in the weld metal, finer micro porosity and uniform distribution of copper in the matrix were found to be the reasons for superior properties of electron beam welds apart from the fine equiaxed grain structure. Transmission electron micrographs of the heat affected zones revealed the precipitate disintegration and over aging in gas tungsten arc welds

  9. 机器人焊接智能化技术与研究现状%Situation and development of interlligentized techonology for arc welding robot

    Institute of Scientific and Technical Information of China (English)

    陈华斌; 黄红雨; 林涛; 张华军; 陈善本

    2013-01-01

    自动化焊接和智能化焊接是实现高效焊接制造的重要手段.系统阐述初始焊位视觉导引与识别、焊缝跟踪、熔池视觉计算及焊接成形质量控制策略等焊接智能化领域的关键技术,特别是以视觉技术为先导的焊接路径导引与规划、视觉-电弧复合传感的空间曲线焊缝跟踪以及基于知识模型的焊接过程建模与控制策略等方面的基础研究,拓展了机器人焊接智能化技术的研究方向和应用领域.融合智能化焊接技术的最新研究成果,研制了轮足组合越障智能焊接机器人,同时还在航天、船舶和海洋重工装备等领域开展了系统集成方面的工程应用..%Automatic welding and intelligent welding have been an important means of high productivity and quality welding manufacturing.In this paper,the fundamental research of the intelligent technologies was described comprehensively as follows.It includes visual guide and recognition of the initial weld position, the method of three dimensional seam tracking with vision-arc compound sensor, knowledge modeling and intelligent control strategies and so on.The achievements in these fields expand the research and application area of the robotic arc welding.Integration of the latest research achievements, a climbing obstacle with wheel foot combined all position arc welding robot was developed.At the same time,the system integration of welding robot station was carried out in the field of aerospace, shipbuilding and marine heavy industry.

  10. Effect of B2O3 containing fluxes on the microstructure and mechanical properties in submerged arc welded mild steel plates

    Science.gov (United States)

    Gupta, P.; Roy, J.; Rai, R. N.; Prasada Rao, A. K.; Saha, S. C.

    2016-02-01

    This paper represents a study on the effect of B2O3 additions in fluxes on the microstructure and mechanical properties of the weld metal formed during Submerged Arc Welding of Mild Steel plates. Five fluxes with about 2.5, 5, 7.5, 10 and 12.5% B2O3 were used with a low carbon electrode. Welding process parameters were kept constant for all the conditions. The microstructure of weld metal for each flux consisted mainly of acicular ferrite, polygonal ferrite, grain boundary ferrites and equiaxed pearlite. It was noted that the Vicker's hardness value was a function of boron content and shows a mixed trend. Impact Energy and Tensile Strength were increased with the increase in boron content in welds this can be attributed to relation with the higher acicular ferrite percentage. However an optimum level of toughness and tensile strength was available with 7.5% and 5% of B2O3 respectively. A qualitative comparison has also be done with fresh flux by means of full metallography and mechanically.

  11. A mathematical approach based on finite differences method for analyzing the temperature field in arc welding of stainless steel thin sheets

    International Nuclear Information System (INIS)

    This work develops a finite difference method to evaluate the temperature field in the heat affected zone in butt welding applied to AISI 304 stainless steel thin sheet by GTAW process. A computer program has been developed and implemented by Visual Basic for Applications (VBA) in MS-Excel spreadsheet. The results that are obtained using the numerical application foresee the thermal behaviour of arc welding processes. An experimental methodology has been developed to validate the mathematical model that allows to measure the temperature in several points close to the weld bead. The methodology is applied to a stainless steel sheet with a thickness lower than 3 mm, although may be used for other steels and welding processes as MIG/MAG and SMAW. The data which has been obtained from the experimental procedure have been used to validate the results that have been calculated by the finite differences numerical method. The mathematical model adjustment has been carried out taking into account the experimental results. The differences found between the experimental and theoretical approaches are due to the convection and radiation heat losses, which have not been considered in the simulation model.With this simple model, the designer will be able to calculate the thermal cycles that take place in the process as well as to predict the temperature field in the proximity of the weld bead. (Author). 18 refs.

  12. Quality control for automatic submerged-arc welding on containment steel liner of Chashma Nuclear Power Plant project

    International Nuclear Information System (INIS)

    The paper introduces the basic constitution of containment steel liner to Pakistan Chashma nuclear power plant (C-2) project, and analyses the origin for the endless crack in the welding joints of SAW. To prevent occurring of endless cracks in SAW, well match of the main welding parameters is the base way to eliminate the weld of big reinforcement and small width. Correct chose and reuse of granular of welding flux is important for reducing of the blowhole and pit on weld surface. Secondary cutting can mitigate the deformation of the whole plate after welding. (author)

  13. Dynamic processes and kinetic theory of plasma fluctuations: ARCS3

    International Nuclear Information System (INIS)

    Dynamic processes on the ARCS3 fight involve six related coordinate systems: Rocket System, Local Geographic System, Local Geomagnetic System, Global Geographic System, Wave Vector System and Artificial Argon Beam System. The present thesis has found the relationships needed to carry out coordinate transformations between all these six coordinate systems. These coordinate transformations are used to investigate ion trajectories and the directional response of the detector OCTO4. A technique to calculate the 3-component acceleration of the main payload was completed, and the trajectory of the main payload relative to the sub payload was given. A method to use the measured spin plane component of the electric field vector to construct the full 3 dimensional electric field vector in the Local Geomagnetic System has been provided. A model to simulate the artificial argon beam distribution is proposed, and used to calculate the beam's flux, density and evolution. Several kinds of plasma waves were observed by the University of Minnesota ACE detector. To explain the wave observations, a kinetic theory of plasma fluctuations was developed. This theory includes magnetized plasma species with or without parallel streaming. It is also valid for plasma including an unmagnetized two temperature plasma species that is streaming in any direction. As an application of the theory, the thermal fluctuations of the O+ acoustic wave mode was calculated and compared with observations. The O+ - He+ bihybrid mode is also evaluated and compared with the observed wave spectra

  14. 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.

  15. Influencia de la transferencia por arco sobre la microestructura de uniones soldadas usando arco pulsado//Influence of the transfer by arc on the microstructure of welded joint produced by pulsed arc

    Directory of Open Access Journals (Sweden)

    Sandra Patricia Romero-Nieto

    2012-12-01

    Full Text Available Este artículo estudia la influencia de la transferencia de arco pulsado en el proceso de soldadura por arco eléctrico con gas de protección (GMAW, Gas Metal Arc Welding, sobre la microestructura, utilizando dos composiciones de gas de protección y los modos de transferencia de arco pulsado y corto circuito. Se caracterizó la microestructura y las propiedades mecánicas y los resultados indican que se logra una mayor resistencia a la tensión y un perfil de dureza más homogéneo utilizando el modo de transferencia de arco pulsado, debido a que con esta existe una distribución más uniforme del tamaño de grano en lastres zonas de soldadura. La presencia de ferrita acicular fue una constante en todos los tratamientos evaluados, mientras la ferrita widmastatten se presentó con preferencia en la transferencia de arco pulsado.Palabras claves: transferencia en arco pulsado, proceso GMAW, mezclas de gases de protección._______________________________________________________________________________AbstractThis article studies the influence of pulsed arc transfer in the GMAW process on the microstructure, usingtwo shielding gas composition and the pulsed arc and short circuit transfer. The microstructure andmechanical properties was characterized and the results show that is achieved a greater tensile strengthand more homogeneous in the hardness profile using the pulsed arc transfer, because it creates a moreuniform size grain in the three areas of welding. The presence of a circular ferrite was constant in alltreatments tested, while widmastatten ferrite was presented preferably in the pulsed arc transfer.Key words: transfer in pulsed current, GMAW process, shielding gas mixtures

  16. Computational study of flow dynamics from a dc arc plasma jet

    CERN Document Server

    Trelles, Juan Pablo

    2013-01-01

    Plasma jets produced by direct-current (DC) non-transferred arc plasma torches, at the core of technologies ranging from spray coating to pyrolysis, present intricate dynamics due to the coupled interaction of fluid flow, thermal, and electromagnetic phenomena. The flow dynamics from an arc discharge plasma jet are investigated using time-dependent three-dimensional simulations encompassing the dynamics of the arc inside the torch, the evolution of the jet through the discharge environment, and the subsequent impingement of the jet over a flat substrate. The plasma is described by a chemical equilibrium and thermodynamic nonequilibrium (two-temperature) model. The numerical formulation of the physical model is based on a monolithic and fully-coupled treatment of the fluid and electromagnetic equations using a Variational Multiscale Finite Element Method. Simulation results uncover distinct aspects of the flow dynamics, including the jet forcing due to the movement of the electric arc, the prevalence of deviat...

  17. 粗丝CO2气体保护焊在螺旋焊管预焊中的应用%Application in Helical Submerged-arc Welded (SAWH) Pipe Tack-welding of Thick Wire CO2 Gas Shielded Welding

    Institute of Scientific and Technical Information of China (English)

    李伟; 李忠响

    2013-01-01

    介绍了螺旋埋弧焊管预精焊机组中的预焊设备与工艺,分析了进口DC 1500数字化焊接电源的优点.针对目前国内比较成熟的螺旋焊管预焊工艺大都采用Ar+CO2二元保护气体或者Ar+CO2+O2三元保护气体的情况,重点介绍了采用CO2气体保护的预焊工艺的优缺点,对电弧形态和焊接工艺参数进行了分析,提出了CO2气体保护预焊飞溅物和焊缝成形的控制措施.论述了预焊电弧形态和熔滴过渡特点,以及相关工艺参数对焊接过程的影响.%Abstr act:In this paper,it introduced the tack-welding process and equipment of SAWH pipe units,and analyzed the advantages of the imported DC 1500 digital welding power.At present,the Ar+ CO2 binary shielded gas or Ar+ CO2+O2 ternary shielded gas was mostly adopted in SAWH pipe tack-welding process in China domestic,it emphasized on the advantages and disadvantages of CO2 gas shielded welding,analyzed the arc shape and the welding process parameters,and put forward control measures to splash and weld formation of CO2 gas shielded welding tack-welding.In the end,it discussed the arc shape and the characteristics of droplet transfer,and the influence of related process parameters to welding procedure.

  18. Arc Plasma Torch Modeling

    CERN Document Server

    Trelles, J P; Vardelle, A; Heberlein, J V R

    2013-01-01

    Arc plasma torches are the primary components of various industrial thermal plasma processes involving plasma spraying, metal cutting and welding, thermal plasma CVD, metal melting and remelting, waste treatment and gas production. They are relatively simple devices whose operation implies intricate thermal, chemical, electrical, and fluid dynamics phenomena. Modeling may be used as a means to better understand the physical processes involved in their operation. This paper presents an overview of the main aspects involved in the modeling of DC arc plasma torches: the mathematical models including thermodynamic and chemical non-equilibrium models, turbulent and radiative transport, thermodynamic and transport property calculation, boundary conditions and arc reattachment models. It focuses on the conventional plasma torches used for plasma spraying that include a hot-cathode and a nozzle anode.

  19. 厚板铝合金变极性等离子弧焊工艺%Research on VPPA helium arc welding process of thick Al-Mg alloy plate

    Institute of Scientific and Technical Information of China (English)

    薛根奇; 马丽

    2012-01-01

    分析铝镁合金的焊接特性和变极性等离子弧焊的焊接特点及氩-氦电弧的特性,依据8~12 mm板厚5083的焊接经验,选用变极性等离子孤焊,分别采用氩气、氩气+氦气作为保护气体,对16 mm厚的5083铝合金进行焊接试验,通过优化焊接工艺参数,获得良好的焊缝成形;按JB/T 4730《承压设备无损检测》的要求对获得的焊接接头进行射线检测和渗透检测,通过机械性能试验验证焊接接头的机械性能,各项检测及试验结果均符合NB/T 47014《承压设备焊接工艺评定》的要求,获得的焊接工艺规范参数在高压封闭电器外壳筒体的焊接中稳定应用.%Based on the welding properties of aluminum-magnesium alloy,the welding characteristics of variable polarity plasma arc welding (VPPAW)and Argon-helium mixed arc,relay on the practical experience of 8-12mm 5083 alloy in variable polarity plasma arc welding,The variable polarity plasma helium arc welding was used to weld 16mm thick plate 5083 alloy with Argon and Argon-helium gas;Optimized welding parameters by study on die welding process,Gain the welded joints with Excellent weld shape,perfect internal quality and excellent mechanical properties. Use the non-destructive testing of pressure equipment of RT and FT to verify the weld surface and internal quality, verified the mechanical properties of welded joints by mechanical properties tests;The test results in line with the NB/T 47014"welding procedure qualification for pressure equipment",The welding process specification parameters are stable application in the welding of high pressure closed electrical enclosure tube.

  20. Dynamic electron arc radiotherapy (DEAR): a feasibility study

    International Nuclear Information System (INIS)

    Compared to other radiation therapy modalities, clinical electron beam therapy has remained practically unchanged for the past few decades even though electron beams with multiple energies are widely available on most linacs. In this paper, we present the concept of dynamic electron arc radiotherapy (DEAR), a new conformal electron therapy technique with synchronized couch motion. DEAR utilizes combination of gantry rotation, couch motion, and dose rate modulation to achieve desirable dose distributions in patient. The electron applicator is kept to minimize scatter and maintain narrow penumbra. The couch motion is synchronized with the gantry rotation to avoid collision between patient and the electron cone. In this study, we investigate the feasibility of DEAR delivery and demonstrate the potential of DEAR to improve dose distributions on simple cylindrical phantoms. DEAR was delivered on Varian's TrueBeam linac in Research Mode. In conjunction with the recorded trajectory log files, mechanical motion accuracies and dose rate modulation precision were analyzed. Experimental and calculated dose distributions were investigated for different energies (6 and 9 MeV) and cut-out sizes (1×10 cm2 and 3×10 cm2 for a 15×15 cm2 applicator). Our findings show that DEAR delivery is feasible and has the potential to deliver radiation dose with high accuracy (root mean square error, or RMSE of <0.1 MU, <0.1° gantry, and <0.1 cm couch positions) and good dose rate precision (1.6 MU min−1). Dose homogeneity within ±2% in large and curved targets can be achieved while maintaining penumbra comparable to a standard electron beam on a flat surface. Further, DEAR does not require fabrication of patient-specific shields. These benefits make DEAR a promising technique for conformal radiotherapy of superficial tumors. (paper)

  1. Optimization of the pulsed current gas tungsten arc welding (PCGTAW) parameters for corrosion resistance of super duplex stainless steel (UNS S32760) welds using the Taguchi method

    Energy Technology Data Exchange (ETDEWEB)

    Yousefieh, M., E-mail: m.yousefieh@ma.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Shamanian, M., E-mail: shamanian@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Saatchi, A. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

    2011-01-21

    Research highlights: > Among the four factors and three levels tested, it was concluded that the pulse current had the most significant effect on the pitting potential and the background current had the next most significant effect. The effects of pulse frequency and % on time are less important when compared to the other factors. > The percentage contributions of the pulse current, the background current, % on time, and pulse frequency to the corrosion resistance are 66.28%, 25.97%, 2.71% and 5.04%, respectively. > The optimum conditions within the selected parameter values were found as the second level of pulse current (120 A), second level of background current (60 A), third level of % on time (80%) and third level of pulse frequency (5 Hz). > The confirmation test was carried out at optimum working conditions. Pitting potential was increased to 1.06 V{sub SCE} by setting the control factors. Predicted (1.04 V{sub SCE}) and observed (1.06 V{sub SCE}) pitting potential values are close to each other, which are the highest values obtained in the present study. - Abstract: In the present work, a design of experiment (DOE) technique, the Taguchi method, has been used to optimize the pulsed current gas tungsten arc welding (PCGTAW) parameters for the corrosion resistance of super duplex stainless steel (UNS S32760) welds. A L{sub 9} (3{sup 4}) orthogonal array (OA) of Taguchi design which involves nine experiments for four parameters (pulse current, background current, % on time, pulse frequency) with three levels was used. Corrosion resistance in 3.5%NaCl solution was evaluated by anodic polarization tests at room temperature. Analysis of variance (ANOVA) is performed on the measured data and S/N (signal to noise) ratios. The higher the better response category was selected to obtain optimum conditions. The optimum conditions providing the highest pitting potential were estimated. The optimum conditions were found as the second level of pulse current (120 A

  2. 电弧超声技术在焊接工艺中的应用研究%Application Research of Arc Ultrasonic Technology in the Welding Process

    Institute of Scientific and Technical Information of China (English)

    赵波

    2014-01-01

    对电弧超声技术的应用情况进行了综述,分析了电弧超声对焊接接头宏观形貌、焊缝及热影响区金相组织及力学性能的影响规律。分析表明,在电弧超声作用下,显著增强了焊接熔池搅拌作用、加快了焊接热传导,随着激励频率的增加,熔深基本不变,熔宽增大,粗晶区宽度减小,细晶区宽度增大;焊缝、熔合区、粗晶区、细晶区金相组织均明显细化,焊缝区的组织分布更趋均匀化;降低了焊接接头对热输入的敏感性,并使焊接接头在较高的焊接热输入水平下仍能具有良好的冲击韧性,尤其可显著提高焊接接头的低温冲击韧性;能够改善焊缝及其周围区域的残余应力分布,使其分布均匀,变化幅度减小。%The application situation of the arc ultrasonic technology was reviewed. And the influence rules of arc ultrasonic technology on the macrostructure of welded joint, metallurgical structure and mechanical properties of weld & HAZ were summarized and analyzed in this article. The analysis showed that under the effect of the arc ultrasonic technology, the shaking down effect of the molten welding pool is enhanced apparently and the welding heat conduction is accelerated. With the increase of the excitation frequency, the fusion penetration basically remains unchanged, the fusion width is enlarged, the coarse grain zone is narrowed, and the fine grain zone is widened;Meanwhile, the metallurgical structures of the weld, fusion area, coarse grain zone and fine grain zone are all refined obviously, and the microstructure of the weld metal tends to be more homogenized, which reduces the susceptivity of the weld joint to heat input, and ensure a favorable impact toughness (especially the impact toughness at low temperatures) of the weld joint even at a higher welding heat input level;it can also improve the distribution of residual stress in the weld and the area surrounding it and

  3. Use of Aria to simulate laser weld pool dynamics for neutron generator production.

    Energy Technology Data Exchange (ETDEWEB)

    Noble, David R.; Notz, Patrick K.; Martinez, Mario J.; Kraynik, Andrew Michael

    2007-09-01

    This report documents the results for the FY07 ASC Integrated Codes Level 2 Milestone number 2354. The description for this milestone is, 'Demonstrate level set free surface tracking capabilities in ARIA to simulate the dynamics of the formation and time evolution of a weld pool in laser welding applications for neutron generator production'. The specialized boundary conditions and material properties for the laser welding application were implemented and verified by comparison with existing, two-dimensional applications. Analyses of stationary spot welds and traveling line welds were performed and the accuracy of the three-dimensional (3D) level set algorithm is assessed by comparison with 3D moving mesh calculations.

  4. Unified model to the Tungsten inert Gas welding process including the cathode, the plasma and the anode; Modele couple cathode-plasma-piece en vue de la simulation du procede de soudage a l'arc TIG

    Energy Technology Data Exchange (ETDEWEB)

    Brochard, M.

    2009-06-15

    During this work, a 2D axially symmetric model of a TIG arc welding process had been developed in order to predict for given welding parameters, the needed variables for a designer of welded assembly: the heat input on the work piece, the weld pool geometry,... The developed model, using the Cast3M finite elements software, deals with the physical phenomena acting in each part of the process: the cathode, the plasma, the work piece with a weld pool, and the interfaces between these parts. To solve this model, the thermohydraulics equations are coupled with the electromagnetic equations that are calculated in part using the least squares finite element method. The beginning of the model validation consisted in comparing the results obtained with the ones available in the scientific literature. Thus, this step points out the action of each force in the weld pool, the contribution of each heat flux in the energy balance. Finally, to validate the model predictiveness, experimental and numerical sensitivity analyses were conducted using a design of experiments approach. The effects of the process current, the arc gap and the electrode tip angle on the weld pool geometry and the energy transferred to the work piece and the arc efficiency were studied. The good agreement obtained by the developed model for these outputs shows the good reproduction of the process physics. (author)

  5. Effect of optimal weld parameters in the microstructure and mechanical properties of autogeneous gas tungsten arc weldments of super-duplex stainless steel UNS S32750

    International Nuclear Information System (INIS)

    Highlights: • Optimization of process parameters in autogeneous GTA welding of UNS S32750. • Effect of optimal parameters on the metallurgical and mechanical properties. • Pensive discussions on the structure – property relationships. - Abstract: The present study reported the optimization of process parameters such as current and welding speed to achieve maximum penetration in the bead on plate Gas Tungsten Arc Welding (GTAW) of super-duplex stainless steel thick plates by autogeneous-automatic mode. Two factor three level Taguchi L9 orthogonal array was employed to determine the maximum penetration. A maximum penetration of 3.4439 mm with a heat input of 1.17 kJ/mm was obtained on employing a current of 250 A and a welding speed of 150 mm/min. Experimental investigations including microstructure and mechanical properties characterization of the weldments were determined from the established optimal parameters. The results showed that the tensile strength and the impact toughness of the joints obtained from autogeneous GTAW process were found to be 851 MPa and 150 J respectively

  6. Irradiation effects on fracture toughness of two high-copper submerged-arc welds, HSSI Series 5. Volume 1, Main report and Appendices A, B, C, and D

    Energy Technology Data Exchange (ETDEWEB)

    Nanstad, R.K.; Haggag, F.M.; McCabe, D.E.; Iskander, S.K.; Bowman, K.O. [Oak Ridge National Lab., TN (United States); Menke, B.H. [Materials Engineering Associates, Inc., Lanham, MD (United States)

    1992-10-01

    The Fifth Irradiation Series in the Heavy-Section Steel Irradiation Program obtained a statistically significant fracture toughness data base on two high-copper (0.23 and 0.31 wt %) submerged-arc welds to determine the shift and shape of the K{sub Ic} curve as a consequence of irradiation. Compact specimens with thicknesses to 101.6 mm (4 in) in the irradiated condition and 203.2 mm (8 in) in the unirradiated condition were tested, in addition to Charpy impact, tensile, and drop-weight specimens. Irradiations were conducted at a nominal temperature of 288{degree}C and an average fluence of 1.5 {times} 10{sup 19} neutrons/cm{sup 2} (>l MeV). The Charpy 41-J temperature shifts are about the same as the corresponding drop-weight NDT temperature shifts. The irradiated welds exhibited substantial numbers of cleavage pop-ins. Mean curve fits using two-parameter (with fixed intercept) nonlinear and linearized exponential regression analysis revealed that the fracture toughness 100 MPa{lg_bullet}{radical}m shifts exceeded the Charpy 41-J shifts for both welds. Analyses of curve shape changes indicated decreases in the slopes of the fracture toughness curves, especially for the higher copper weld. Weibull analyses were performed to investigate development of lower bound curves to the data, including the use of a variable K{sub min} parameter which affects the curve shape.

  7. Dynamic Interaction between Machine, Tool, and Substrate in Bobbin Friction Stir Welding

    Directory of Open Access Journals (Sweden)

    Mohammad K. Sued

    2016-01-01

    Full Text Available The bobbin friction stir welding (BFSW process has benefits for welding aluminium alloy 6082-T6 in the boat-building industry. However this alloy is difficult to weld in the thin state. There are a large number of process variables and covert situational factors that affect weld quality. This paper investigates how tool holder and machine-type affect BFSW weld quality of 4 mm Al6082-T6. The variables were tool features (three types, machine-controller type (two types, and tool holder (fixed versus floating. Fourier analysis was performed on motor spindle current to determine the frequency response of the machine. An interaction was found between the computer numerical control (CNC, the degrees of freedom of the tool holder, and the substrate (workpiece. The conventional idea that the welding tool has a semisteady interaction with the substrate is not supported. Instead the interaction is highly dynamic, and this materially affects the weld quality. Specific vibrational interactions are associated with poor welding. The CNC machine-type also emerges as a neglected variable that needs to be given attention in the selection of process parameters. Although compliance in the tool holder might seem useful, it is shown to have negative consequences as it introduces tool positioning problems.

  8. Radioactive waste combustion / vitrification under arc plasma: thermal and dynamic modelling

    International Nuclear Information System (INIS)

    This thesis concerns the thermal and dynamic modelling for a combustion/vitrification process of surrogate radioactive waste under transferred arc plasma. The writer presents the confinement processes for radioactive waste using arc plasma and the different software used to model theses processes. This is followed by a description of our experimental equipment including a plasma arc reactor and an inductive system allowing the homogenization of glass temperature. A combustion/vitrification test is described. Thermal and material balances were discussed. The temperature fields of plasma arc and the glass frit conductivity are measured. Finally, the writer describes and clarifies the equations solved for the simulations of the electrically plasma arc and the glass melting including the thin layer of glass frit coating the crucible cold walls. The modelling results are presented in the form of spatial distribution of temperature, velocity and volume power... (author)

  9. Dynamic and spectroscopic characteristics of atmospheric gliding arc in gas-liquid two-phase flow

    International Nuclear Information System (INIS)

    In this study, an atmospheric alternating-current gliding arc device in gas-liquid two-phase flow has been developed for the purpose of waste water degradation. The dynamic behavior of the gas-liquid gliding arc is investigated through the oscillations of electrical signals, while the spatial evolution of the arc column is analyzed by high speed photography. Different arc breakdown regimes are reported, and the restrike mode is identified as the typical fluctuation characteristic of the hybrid gliding arc in air-water mixture. Optical emission spectroscopy is employed to investigate the active species generated in the gas-liquid plasma. The axial evolution of the OH (309 nm) intensity is determined, while the rotational and vibrational temperatures of the OH are obtained by a comparison between the experimental and simulated spectra. The significant discrepancy between the rotational and translational temperatures has also been discussed.

  10. 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...

  11. Investigations on intercrystalline resistance of plasma arc-welded coating materials X 2 CrNiNb 19 9 and S-NiCr 20 Nb

    International Nuclear Information System (INIS)

    The resistance to intercrystalline corrosion (IC) has been tested on single and double layer plasma arc-weldings of austenite steel X2CrNiNb199 as well as the alloy inconel 82 (S-NiCr 20 Nb) using short-term testing methods. The austenite platings can be considered as IC resistant. The inconel alloy tends to selective corrosion in the potential range of -30 to +30 mVEsub(H), the areas of greater precipitation are particularly attacked. (GSCH)

  12. Ultrasonic sensing of GMAW: Laser/EMAT defect detection system. [Gas Metal Arc Welding (GMAW), Electromagnetic acoustic transducer (EMAT)

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, N.M.; Johnson, J.A.; Larsen, E.D. (EG and G Idaho, Inc., Idaho Falls, ID (United States)); Van Clark, A. Jr.; Schaps, S.R.; Fortunko, C.M. (National Inst. of Standards and Technology, Boulder, CO (United States))

    1992-01-01

    In-process ultrasonic sensing of welding allows detection of weld defects in real time. A noncontacting ultrasonic system is being developed to operate in a production environment. The principal components are a pulsed laser for ultrasound generation and an electromagnetic acoustic transducer (EMAT) for ultrasound reception. A PC-based data acquisition system determines the quality of the weld on a pass-by-pass basis. The laser/EMAT system interrogates the area in the weld volume where defects are most likely to occur. This area of interest is identified by computer calculations on a pass-by-pass basis using weld planning information provided by the off-line programmer. The absence of a signal above the threshold level in the computer-calculated time interval indicates a disruption of the sound path by a defect. The ultrasonic sensor system then provides an input signal to the weld controller about the defect condition. 8 refs.

  13. Crustal Genesis and Dynamics in the Jurassic Talkeetna Arc

    Science.gov (United States)

    Kelemen, P.; Amato, J.; Behn, M.; Blusztajn, J.; Christensen, N.; Clift, P.; Debari, S.; Draut, A.; Greene, A.; Hacker, B.; Hanghoj, K.; Hart, S.; Hirth, G.; Mattinson, J.; Mehl, L.; Pavlis, T.; Rioux, M.; Trop, J.

    2005-12-01

    We summarize studies of the accreted Talkeetna arc section in Alaska, focusing on the role of arc crust in continental genesis and arc geodynamics. The 200 to 175 Ma section extends from residual mantle peridotite to volcanics, including - in order of decreasing depth - a few 100 m of pyroxenite, rare garnet granulites, cumulate gabbronorites, and felsic plutonic rocks. Lack of inheritance in zircon and relatively constant, high Nd and low Sr isotope ratios indicate that to first order the crustal rocks differentiated from a common parental melt composition and that magmas did not incorporate older crustal material. Amphibolite formed from arc lava. Metasediment had pelagic protoliths, except on the Alaska Peninsula. The arc probably formed new crust during extension, rather than intruding older rocks. South to north younging of zircon and hornblende ages indicates that the arc migrated northward, so the entire section is not a single, tilted vertical column though the Chugach region alone could be. Total crustal thickness was 25 to 35 km, with 6 to 8 km of volcanics. Mid to lower crust is mainly cumulate gabbronorite formed at NNO+2. The thickness of lavas/cumulates is consistent with crystal fractionation to form average lavas from the most primitive observed melt compositions. The bulk composition of the crust and the most primitive melts has ~ 49 wt% SiO2, 19 wt% Al2O3, 8 wt% MgO, and Mg# ~ 60. Derivation of these melts from magmas in equilibrium with residual mantle (melt Mg# > 70) requires more than 25% crystal fractionation of cumulates with cpx Mg# between 85 and 93, found only in primitive pyroxenite along the Moho, ~ 1% of the crustal thickness. This discrepancy is likely due to foundering of dense pyroxenites (and garnet granulites) into underlying mantle. Flat REE patterns, low K, low Th/La, and low Mg# at a given SiO2 distinguish Talkeetna most samples from continental crust, which is Th-enriched, LREE enriched, HREE depleted, K-rich, high Mg# andesite

  14. Dynamic and control system analysis of two-wheeled robot for welding application

    Institute of Scientific and Technical Information of China (English)

    王晓宇; 赵杰; 蔡鹤皋

    2004-01-01

    Aiming at the welding condition of space complex seam is uncertain and the intelligence of welding robot is unideal, a two-wheeled mobile robot is developed. It not only has the capacity of autonomous decision and avoiding obstacles, but also can flexibly move and strongly adapt variable environment. The composition of the welding robot is described and the dynamic model is established. The feasible control strategy and control algorithm is put forward. The simulation experiments of real world are conducted, the results are satisfying.

  15. Computer simulation of short-circuiting transfer welding under waveform control on inverter power source

    Institute of Scientific and Technical Information of China (English)

    Yang Lijun; Feng Shengqiang; Dong Tianshun; Li Huan

    2007-01-01

    A simulation model is introduced about the non-linearity process of short-circuiting transfer in CO2 arc welding for displaying the interaction between the inverter power source and welding arc under waveform control. In the simulation model, the feedback signals of current and voltage are taken respectively at the different phase in a short circuit periodic time and applied to the PWM(pulse width modulation) module in a model of inverter power source to control the output of power source. The simulation operation about the dynamic process of CO2 short-circuiting transfer welding is implemented on the founded simulation model with a peak arc current of 400 A and a peak voltage of 35 V, producing the dynamic arc waveforms which can embody the effect of inverter harmonic wave. The simulating waveforms are close to that of welding experiments.

  16. 基于结构光的机器人弧焊混合视觉伺服控制%Hybrid Visual Servoing Control for Robotic Arc Welding Based on Structured Light Vision

    Institute of Scientific and Technical Information of China (English)

    徐德; 王麟琨; 涂志国; 谭民

    2005-01-01

    A novel hybrid visual servoing control method based on structured light vision is proposed for robotic arc welding with a general six degrees of freedom robot. It consists of a position control inner-loop in Cartesian space and two outer-loops. One is position-based visual control in Cartesian space for moving in the direction of weld seam, i.e., weld seam tracking, another is imagebased visual control in image space for adjustment to eliminate the errors in the process of tracking.A new Jacobian matrix from image space of the feature point on structured light stripe to Cartesian space is provided for differential movement of the end-effector. The control system model is simplified and its stability is discussed. An experiment of arc welding protected by gas CO2 for verifying is well conducted.

  17. Creating dynamic equivalent PV circuit models with impedance spectroscopy for arc-fault modeling.

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Jay Dean; Kuszmaul, Scott S.; Strauch, Jason E.; Schoenwald, David Alan

    2011-06-01

    Article 690.11 in the 2011 National Electrical Code{reg_sign} (NEC{reg_sign}) requires new photovoltaic (PV) systems on or penetrating a building to include a listed arc fault protection device. Currently there is little experimental or empirical research into the behavior of the arcing frequencies through PV components despite the potential for modules and other PV components to filter or attenuate arcing signatures that could render the arc detector ineffective. To model AC arcing signal propagation along PV strings, the well-studied DC diode models were found to inadequately capture the behavior of high frequency arcing signals. Instead dynamic equivalent circuit models of PV modules were required to describe the impedance for alternating currents in modules. The nonlinearities present in PV cells resulting from irradiance, temperature, frequency, and bias voltage variations make modeling these systems challenging. Linearized dynamic equivalent circuits were created for multiple PV module manufacturers and module technologies. The equivalent resistances and capacitances for the modules were determined using impedance spectroscopy with no bias voltage and no irradiance. The equivalent circuit model was employed to evaluate modules having irradiance conditions that could not be measured directly with the instrumentation. Although there was a wide range of circuit component values, the complex impedance model does not predict filtering of arc fault frequencies in PV strings for any irradiance level. Experimental results with no irradiance agree with the model and show nearly no attenuation for 1 Hz to 100 kHz input frequencies.

  18. 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.

  19. On the dynamics of cutting arc plasmas: the role of the power supply ripple

    Directory of Open Access Journals (Sweden)

    Leandro Prevosto

    2012-08-01

    Full Text Available The power sources used in cutting arc torches are usually poorly stabilized and have a large ripple factor. The strong oscillatory components in the voltage and arc current produce in turn, large fluctuations in the plasma quantities. Experimental observations on the dynamics of the non-equilibrium plasma inside the nozzle of a 30 A oxygen cutting torch with a 7 % ripple level of its power source are reported in this work.

  20. On the dynamics of cutting arc plasmas: the role of the power supply ripple

    OpenAIRE

    Leandro Prevosto

    2012-01-01

    The power sources used in cutting arc torches are usually poorly stabilized and have a large ripple factor. The strong oscillatory components in the voltage and arc current produce in turn, large fluctuations in the plasma quantities. Experimental observations on the dynamics of the non-equilibrium plasma inside the nozzle of a 30 A oxygen cutting torch with a 7 % ripple level of its power source are reported in this work.

  1. Thermal and dynamic effects in electron beam welding cavities

    International Nuclear Information System (INIS)

    An experimental and analytical study of the temperature distributions along the molten metal surface in an electron beam welding cavity is described. Surface temperature distributions in cavities were measured with a narrow band infrared radiation pyrometer. The availability of the cavity temperature measurements allowed estimates to be made for the vapor pressure and surface energy forces as a function of cavity position. The results indicated a force imbalance occurred in the cavity. It is postulated that at the location of the force imbalance a liquid material projection forms periodically and moves into the path of the electron beam. The liquid in this projection is driven towards the bottom, partially filling the cavity. This action is followed by the electron beam pushing the liquid aside to form a maximum depth cavity. This process is then repeated. An analysis for predicting cavity oscillation frequency shows reasonable agreement with frequencies measured at the weld root determined from weld sections. A study of the measured temperature distributions in cavities of varying depth combined with the force imbalance observations led to an interpretation of when spiking might occur. A procedure is proposed for determining the spiking tendency for a given set of weld parameters. The results of this study permit a designer to select apriori the best set of weld parameters to achieve a weld of predictable quality

  2. Mechanical behaviour of Astm A 297 grade Hp joints welded using different processes

    International Nuclear Information System (INIS)

    The influence of different arc welding processes on mechanical behaviour was studied for cast heat resistant stainless steel welded joints, in the as welded conditions. ASTM A 297 grade HP with niobium and niobium/titanium additions were welded following three different welding procedures, using shielded metal arc welding gas tungsten arc welding and plasma arc welding, in six welded joints. The welded joint mechanical behaviour was evaluated by ambient temperature and 870 deg C tensile tests; and creep tests at 900 deg C and 50 MPa. Mechanical test results showed that the welding procedure qualification following welding codes is not suitable for high temperature service applications. (author)

  3. Recently developed technology in narrow gap welding of thick plates using the GMAW and submerged arc processes

    International Nuclear Information System (INIS)

    Device with weaving head for narrow gap welding suitable for the GMAW and SAW processes. Technological properties of welded joints on steels 20 MnMoNi 55 and 15 NiCuMoNb 5 having subjected to different heat treatments. (orig.)

  4. Irradiation behavior of a submerged arc welding material with different copper content; Bestrahlungsverhalten einer UP-Versuchsschweissnaht mit unterschiedlichen Kupfergehalten

    Energy Technology Data Exchange (ETDEWEB)

    Langer, R. [Siemens AG Energieerzeugung KWU, Erlangen (Germany); Bartsch, R. [Kernkraftwerk Obrigheim GmbH (Germany)

    1998-11-01

    Che report presents results of an irradiation program on specimens of submerged arc weldings with copper contents of 0.14% up to 0.42% and a fluence up to 2.2E19 cm{sup -2} (E>1MeV). Unirradiated and irradiated tensile- Charpy-, K{sub lc}- and Pellini-specimens were tested of material with a copper content of 0.22%. On the other materials Charpy tests and tensile tests were performed. The irradiation of the specimens took place in the KWO - ``RPV, a PWR with low flux and in the VAK - RPV, a small BWR with high flux. - The irradiation induced embrittlemnt shows a copper dependence up to about 30%. The specimens with a copper content higher than 0.30% show no further embrittlement. Irradiation in different reactors with different flux (factor > 33) shows the same state of embrittlement. Determination of a K{sub lc}, T-curve with irradiated specimens is possible. The conservative of the RT{sub NDT} - concept could be confirmed by the results of Charpy-V, drop weight- and K{sub lc}-test results. [Deutsch] Zur zusaetzlichen Absicherung des KWO-RDB wurde Ende 1979 eine UP-Versuchsschweissnaht mit vergleichbarer chemischer Zusammensetzung und vergleibaren mechanisch-technologischen Werkstoffen im unbestrahlten Ausgangszustand wie die RDB Core-Rundnaht hergestellt. Teile der Naht wurden durch Verkupfern der Schweissdraehte auf unterschiedliche Gehalte von Cu=0,14% bis 0,42% eingestellt. Aus dieser Schweissverbindung wurden Proben im VAK und KWO-RDB bestrahlt. Im Rahmen der Aktivitaeten zur Absicherung des KWO-RDBs erfolgte 1995 die Pruefung der bestrahlten Proben. Die mechanisch technologischen Werkstoffwerte vor und nach Bestrahlung werden gegenuebergestellt und praesentiert. Mit dem Ergebnis wurde ein weiterer Nachweis fuer die Konservativitaet des RT{sub NDT}-Konzeptes erbracht. Es wurde nachgewiesen, dass fuer den untersuchten Bereich kein Dose-Rate Effekt bzw. Bestrahlungszeiteinfluss existiert. Fuer UP-Schweissungen mit den vorliegenden Fertigungsparametern und bei

  5. 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.)

  6. Dynamic simulation of the temperature field of stainless steel laser welding

    International Nuclear Information System (INIS)

    The distribution of the temperature field in laser welding based on stainless steel 304 sheet was dynamically simulated by the FEA software - ANSYS in this paper. In view of the characters of laser welding, a travel heat source combined with the body loads was designed by analyzing both the temperature relativity of the thermal physical parameters of material and latent heat of fusion and the effect of convection radiation on temperature field. Considering the high nonlinear of the laser welding process, the transition element modeling was adopted. During load history, a residue control method was taken to ensure the precision of node selection. Through the calculation, it was shown that the simulation results of weld shape were in accordance with the experimental results

  7. 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)

  8. Dynamics of cathode spots in low-pressure arc plasma removing oxide layer on steel surfaces

    Science.gov (United States)

    Tang, Z. L.; Yang, K.; Liu, H. X.; Zhang, Y. C.; Li, H.; Zhu, X. D.

    2016-03-01

    The dynamics of cathode spots has been investigated in low-pressure arc plasma for removing oxide layer on low carbon steel surfaces. The motion of cathode spots was observed with a high speed camera, and the arc voltage was analyzed by fast Fourier transform. The spots move on clean steel surface as a random walk, and the low-frequency components dominated the voltage waveform. However, the spots on steel surfaces with oxide layer tend to burn on the rim of the eroded area formed in the previous arcing, and the low-frequency components decrease correspondingly. The "color" of the colored random noise for arc voltage varies from the approximate brown noise for clean steel surface to pink noise for thick oxide layer, where the edge effect of boundary is considered to play a significant role.

  9. 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...

  10. Plasma Processes : Arc root dynamics in high power plasma torches – Evidence of chaotic behavior

    Indian Academy of Sciences (India)

    A K Das

    2000-11-01

    Although plasma torches have been commercially available for about 50 years, areas such as plasma gun design, process efficiency, reproducibility, plasma stability, torch lives etc. have remained mostly unattended. Recent torch developments have been focusing on the basic understanding of the plasma column and its dynamics inside the plasma torch, the interaction of plasma jet and the powders, the interaction of the plasma jet with surroundings and the impingement of the jet on the substrate. Two of the major causes of erratic and poor performance of a variety of thermal plasma processes are currently identified as the fluctuations arising out of the arc root movement on the electrodes inside the plasma torch and the fluid dynamic instabilities arising out of entrainment of the air into the plasma jet. This paper reviews the current state of understanding of these fluctuations as well as the dynamics of arc root movement in plasma torches. The work done at the author’s laboratory on studying the fluctuations in arc voltage, arc current, acoustic emissions and optical emissions are also presented. These fluctuations are observed to be chaotic and interrelated. Real time monitoring and controlling the arc instabilities through chaos characterization parameters can greatly contribute to the understanding of electrode erosion as well as improvement of plasma torch lifetime.

  11. 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.

  12. Soudage hybride Laser-MAG d'un acier Hardox® Hybrid Laser Arc Welding of a Hardox® steel

    Directory of Open Access Journals (Sweden)

    Chaussé Fabrice

    2013-11-01

    Full Text Available Le soudage hybride laser-MAG est un procédé fortement compétitif par rapport aux procédés conventionnels notamment pour le soudage de fortes épaisseurs et les grandes longueurs de soudure. Il connait de ce fait un développement important dans l'industrie. La présente étude s'est portée sur la soudabilité de l'acier Hardox® par ce procédé. Un large panel de techniques de caractérisation a été employé (mesures thermiques, radiographie X, duretés Vickers, macrographie…. L'objectif étant de déterminer l'influence des paramètres du procédé sur la qualité de la soudure et d'étendre notre compréhension des phénomènes se déroulant lors de ce type de soudage. Hybrid Laser Arc Welding (HLAW technology is a highly competitive metal joining process especially when high productivity is needed and for the welding of thick plates. It is a really new technology but its implementation in industry accelerates thanks to recent improvements of high power laser equipment and development of integrated hybrid welding heads. This study focuses on weldability of Hardox® 450 steel by HLAW. Welding tests were conducted by making critical process parameters vary. Then a large panel of characterization techniques (X-Ray radiography, macroscopic examination and hardness mapping was used to determine process parameters influence on weldability of Hardox 450® Steel.

  13. Effect of Included Angle in V-Groove Butt Joints on Shrinkages in Submerged Arc Welding Process

    OpenAIRE

    N. Lakshmana Swamy; G. MAHENDRAMANI

    2012-01-01

    The problems of distortion, residual stresses and reduced strength of structure in and around a welded joint are of major concern in the shipbuilding industry and in other similar manufacturing industries. The predictions of the degree of shrinkages in ship panels due to welding are of great importance from the point of view of dimensional control and it is important to analyze transverse and longitudinal shrinkage. This paper deals with the experimental analysis of transverse and longitudina...

  14. PLC在钉头管埋弧螺柱焊中的应用%The Application of Programmable Logical Controller (PLC) in Submerged Arc Stud Welding for Pin Finned Tube

    Institute of Scientific and Technical Information of China (English)

    周拨云; 梅强

    2011-01-01

    In order to accurately control pin finned tube welding procedure, the PLC was applied into the control of pin finned tube submerged arc stud welding. This article introduced SSAW for pin finned tube composition and control requirements of welding control system, this system selected Emerson EC10-2416BTA programmable logical controller, adopted Emerson Control Start software to workout control procedure, and realized automatic welding for pin finned tube submerged arc stud welding. This system is with high efficiency energy saving, it overcomes some disadvantages of manual welding,such as great labour intensity,bad quality of welding joints and low welding efficiency,at the same time, this system can identify failure, alarm and timely deal with, so it can ensure stable welding quality.%为了对钉头管焊接过程进行精确控制,将PLC应用于钉头管埋弧螺柱焊焊接控制.介绍了钉头管埋弧螺柱焊焊接控制系统的组成及控制要求,选用了艾默生EC10-2416BTA型可编程控制器,采用艾默生编程软件Control Start编制控制程序,实现了钉头管埋弧螺柱焊的自动化焊接.该系统高效节能,并克服了手工焊劳动强度大、接头质量差、焊接效率低等缺点,具有故障诊断和报警功能,并作出相应的处理,保证稳定焊接质量.

  15. EFFECT OF DYNAMIC LOADING ON FRACTURE BEHAVIOR OF WELDED JOINTS OF STRUCTURAL STEEL

    Institute of Scientific and Technical Information of China (English)

    Zhang Li; Zhang Yufeng; Huo Lixing

    2004-01-01

    To investigate the effect of dynamic loading on fracture behavior of welded joints of structural steel Q235B and 16Mn in common use and compare the earthquake resistances of the two kinds of materials, dynamic tension and fracture toughness tests are carried out at room temperature. On the basis of the tests, the stress-strain fields near the crack tip of the compact specimens are analyzed by three-dimensional finite element model. The test results and finite element analysis results show that, the fracture toughness of welds and base metal of 16Mn steel increases with the increment of loading rate. Compared with 16Mn steel, Q235B steel is more sensitive to dynamic loading. The fracture toughness of welds of Q235B is comparatively low under static loading and dynamic loading at room temperature. Compared with the static loading, the fracture toughness of Q235B parent metal under dynamic loading decreases by about four times. Therefore, it can be concluded that compared with 16Mn steel, the earthquake resistances of weld and parent metal of Q235B are rather poor.

  16. Analysis and application of GEWI sleeve weld-ability (Material: C45)

    International Nuclear Information System (INIS)

    Welding may use two kinds of welding process of shielded metal arc welding and CO2 shielded arc welding between inner ring in nuclear island steel lining (material: P265GH) and GEWI sleeve (material:C45).CO2 shielded arc welding is often used because of higher welding efficiency, in particular, in condition of plan press, but quality can come into being some problems if we lack strict measures, for example welding procedure. Shielded metal arc welding control easier quality, but welding efficiency is lower. Comparing and analyzing Weld-ability of C45(Medium carbon Quenched and Tempered Steel.) between of shielded metal arc welding and CO2 shielded arc welding, suggest to use shielded metal arc welding in project practice, and control strict welding procedure measure of pre-heating treatment and Post-heating. (authors)

  17. 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.

  18. Welding process impact on residual stress and distortion

    OpenAIRE

    Colegrove, Paul A.; Ikeagu, C.; Thistlethwaite, A; Williams, Stewart W.; Nagy, T.; Suder, Wojciech; STEUWER, Axel; Pirling, T.

    2009-01-01

    Residual stress and distortion continue to be important issues in shipbuilding and are still subject to large amounts of research. This paper demonstrates how the type of welding process influences the amount of distortion. Many shipyards currently use submerged arc welding (SAW) as their welding process of choice. In this manuscript we compare welds made by SAW with DC gas metal arc welding, pulsed gas metal arc welding, Fronius Cold Metal Transfer (CMT), autogenous laser a...

  19. An Evaluation of Welding Processes to Reduce Hexavalent Chromium Exposures and Reduce Costs by Using Better Welding Techniques

    OpenAIRE

    Keane, Michael J.

    2014-01-01

    A group of stainless steel arc welding processes was compared for emission rates of fume and hexavalent chromium, and costs per meter length of weld. The objective was to identify those with minimal emissions and also compare relative labor and consumables costs. The selection included flux-cored arc welding (FCAW), shielded-metal arc welding (SMAW), and multiple gas metal arc welding (GMAW) processes. Using a conical chamber, fumes were collected, and fume generation rates and hexavalent chr...

  20. Use Of Dynamic Resistance And Dynamic Energy To Compare Two Resistance Spot Welding Equipments For Automotive Industry In Zinc Coated And Uncoated Sheets.

    Directory of Open Access Journals (Sweden)

    Márcio Batista

    2013-01-01

    Full Text Available Resistance spot welding is a fabrication process highly used in the structures assembly. This fact evidences the importance of this welding process control, due to its efficiency, productivity speediness and straightforward simple automation. This work aimed to study the weldability of zinc coated and uncoated steel sheets for automotive industry, comparing the performance of two welding equipments with two current outputkinds: alternating current (AC and medium frequency direct current (DC. The welding parameters were kept constant: 260 kgf (force, 150 ms (time and 7.0 kA (welding current, based upon an optimization parameters methodology. The joints were characterized using optical metallography (spot diameter, indentation depth and weld penetration depth, mechanical tensile-shear tests and electrical measurements: contact electrical resistance, dynamic resistance and dynamic energy. The results showed that welding in medium frequency direct current was more efficient in generating heat in zinc coated sheets and uncoated sheets than alternating current equipment. In welding using AC and DC equipments in zinc coated sheets, the spot weld time formation was 25ms longer than uncoated steel sheets spot weld time. The burn of zinc during welding did not damage the spot weld formation with AC or DC equipments. The electrical contact resistance increased with the roughnessand also presented 52% higher in uncoated sheets than in zinc coated sheets. Finally, the increase in dynamicresistance and dynamic energy augmented the spot weld diameter for both welding equipments. As a final conclusion, the medium frequency direct current equipment presented better results than wave alternating current