WorldWideScience

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. Effects of shielding gas composition on arc profile and molten pool dynamics in gas metal arc welding of steels

    Science.gov (United States)

    Wang, L. L.; Lu, F. G.; Wang, H. P.; Murphy, A. B.; Tang, X. H.

    2014-11-01

    In gas metal arc welding, gases of different compositions are used to produce an arc plasma, which heats and melts the workpiece. They also protect the workpiece from the influence of the air during the welding process. This paper models gas metal arc welding (GMAW) processes using an in-house simulation code. It investigates the effects of the gas composition on the temperature distribution in the arc and on the molten pool dynamics in gas metal arc welding of steels. Pure argon, pure CO2 and different mixtures of argon and CO2 are considered in the study. The model is validated by comparing the calculated weld profiles with physical weld measurements. The numerical calculations reveal that gas composition greatly affects the arc temperature profile, heat transfer to the workpiece, and consequently the weld dimension. As the CO2 content in the shielding gas increases, a more constricted arc plasma with higher energy density is generated as a result of the increased current density in the arc centre and increased Lorentz force. The calculation also shows that the heat transferred from the arc to the workpiece increases with increasing CO2 content, resulting in a wider and deeper weld pool and decreased reinforcement height.

  3. ARc Welding (Industrial Processing Series).

    Science.gov (United States)

    ARC WELDING , *BIBLIOGRAPHIES), (*ARC WELDS, BIBLIOGRAPHIES), ALUMINUM ALLOYS, TITANIUM ALLOYS, CHROMIUM ALLOYS, METAL PLATES, SPOT WELDING , STEEL...INERT GAS WELDING , MARAGING STEELS, MICROSTRUCTURE, HEAT RESISTANT ALLOYS, HEAT RESISTANT METALS, WELDABILITY, MECHANICAL PROPERTIES, MOLYBDENUM ALLOYS, NICKEL ALLOYS, RESISTANCE WELDING

  4. 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.

  5. Welding arc plasma physics

    Science.gov (United States)

    Cain, Bruce L.

    1990-01-01

    The problems of weld quality control and weld process dependability continue to be relevant issues in modern metal welding technology. These become especially important for NASA missions which may require the assembly or repair of larger orbiting platforms using automatic welding techniques. To extend present welding technologies for such applications, NASA/MSFC's Materials and Processes Lab is developing physical models of the arc welding process with the goal of providing both a basis for improved design of weld control systems, and a better understanding of how arc welding variables influence final weld properties. The physics of the plasma arc discharge is reasonably well established in terms of transport processes occurring in the arc column itself, although recourse to sophisticated numerical treatments is normally required to obtain quantitative results. Unfortunately the rigor of these numerical computations often obscures the physics of the underlying model due to its inherent complexity. In contrast, this work has focused on a relatively simple physical model of the arc discharge to describe the gross features observed in welding arcs. Emphasis was placed of deriving analytic expressions for the voltage along the arc axis as a function of known or measurable arc parameters. The model retains the essential physics for a straight polarity, diffusion dominated free burning arc in argon, with major simplifications of collisionless sheaths and simple energy balances at the electrodes.

  6. Variable polarity arc welding

    Science.gov (United States)

    Bayless, E. O., Jr.

    1991-01-01

    Technological advances generate within themselves dissatisfactions that lead to further advances in a process. A series of advances in welding technology which culminated in the Variable Polarity Plasma Arc (VPPA) Welding Process and an advance instituted to overcome the latest dissatisfactions with the process: automated VPPA welding are described briefly.

  7. 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.

  8. Simulation on Dynamic Characteristic of Negative Resistance Arc in Pulsed TIG Welding

    Institute of Scientific and Technical Information of China (English)

    YANG Lijun; HAN Pengbo; DONG Tianshun; ZHANG Jian; XU Licheng

    2007-01-01

    A mathematical model is established on the basis of the physical characteristic of the negative resistance arc when a low current of 0-50 A is applied in pulsed TIG welding. The simulation model converted from the mathematical model is run in MATLAB environment, and the discussion is focused on the way the peak current ranging from 29 A to 50 A and the time constant of arc in the span of 0.003-0.006 s influence the simulating results and the dynamic characteristic. The simulating data are close to that of welding experiments and correspond to the theoretical conclusion.

  9. Alternating-Polarity Arc Welding

    Science.gov (United States)

    Schwinghamer, R. J.

    1987-01-01

    Brief reversing polarity of welding current greatly improves quality of welds. NASA technical memorandum recounts progress in art of variable-polarity plasma-arc (VPPA) welding, with emphasis on welding of aluminum-alloy tanks. VPPA welders offer important advantages over conventional single-polarity gas/tungsten arc welders.

  10. 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...

  11. Vacuum Gas Tungsten Arc Welding

    Science.gov (United States)

    Weeks, J. L.; Todd, D. T.; Wooten, J. R.

    1997-01-01

    A two-year program investigated vacuum gas tungsten arc welding (VGTAW) as a method to modify or improve the weldability of normally difficult-to-weld materials. After a vacuum chamber and GTAW power supply were modified, several difficult-to-weld materials were studied and key parameters developed. Finally, Incoloy 903 weld overlays were produced without microfissures.

  12. Gas arc constriction for plasma arc welding

    Science.gov (United States)

    McGee, William F. (Inventor); Rybicki, Daniel J. (Inventor)

    1994-01-01

    A welding torch for plasma arc welding apparatus has an inert gas applied circumferentially about the arc column externally of the constricting nozzle so as to apply a constricting force on the arc after it has exited the nozzle orifice and downstream of the auxiliary shielding gas. The constricting inert gas is supplied to a plenum chamber about the body of the torch and exits through a series of circumferentially disposed orifices in an annular wall forming a closure at the forward end of the constricting gas plenum chamber. The constricting force of the circumferential gas flow about the arc concentrates and focuses the arc column into a more narrow and dense column of energy after exiting the nozzle orifice so that the arc better retains its energy density prior to contacting the workpiece.

  13. 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.

  14. Thermal insulation of wet shielded metal arc welds

    Science.gov (United States)

    Keenan, Patrick J.

    1993-06-01

    Computational and experimental studies were performed to determine the effect of static thermal insulation on the quality of wet shielded metal arc welds (SMAW). A commercially available heat flow and fluid dynamics spectral-element computer program was used to model a wet SMAW and to determine the potential effect on the weld cooling rate of placing thermal insulation adjacent to the weld line. Experimental manual welds were made on a low carbon equivalent (0.285) mild steel and on a higher carbon equivalent (0.410) high tensile strength steel, using woven fabrics of alumina-boria-silica fibers to insulate the surface of the plate being welded. The effect of the insulation on weld quality was evaluated through the use of post-weld Rockwell Scale hardness measurements on the surface of the weld heat affected zones (HAZ's) and by visual inspection of sectioned welds at 10 X magnification. The computational simulation demonstrated a 150% increase in surface HAZ peak temperature and a significant decrease in weld cooling rate with respect to uninsulated welds, for welds in which ideal insulation had been placed on the base plate surface adjacent to the weld line. Experimental mild steel welds showed a reduction in surface HAZ hardness attributable to insulation at a 77% significance level. A visual comparison of the cross-sections of two welds made in 0.410 carbon equivalent steel-with approximately equivalent heat input-revealed underbead cracking in the uninsulated weld but not in the insulated weld.

  15. Numerical Simulation of the TIG Welding Arc Behavior

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Achieving an effective utilization and exploitation of TIG welding arcs require a thorough understanding of the plasmaproperties and its physical processes. Through simultaneous solutions of the set of conservation equations for mass,momentum, energy and current, a mathematical model has been developed to predict the velocity, temperature,and current density distributions in argon welding arcs. The predicted temperature fields in arc regions, and thedistribution of current density and heat flux at the anode agree well with measurements reported in literatures. Thiswork could lay the foundation for developing a comprehensive model of the TIG welding process where a dynamic,two-way coupling between the welding arc and the weld pool surface is properly represented.

  16. Feedback Linearization Based Arc Length Control for Gas Metal Arc Welding

    DEFF Research Database (Denmark)

    Thomsen, Jesper Sandberg

    2005-01-01

    In this paper a feedback linearization based arc length controller for gas metal arc welding (GMAW) is described. A nonlinear model describing the dynamic arc length is transformed into a system where nonlinearities can be cancelled by a nonlinear state feedback control part, and thus, leaving only...

  17. 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.

  18. Gas Tungsten Arc Welding. Welding Module 6. Instructor's Guide.

    Science.gov (United States)

    Missouri Univ., Columbia. Instructional Materials Lab.

    This guide is intended to assist vocational educators in teaching a three-unit module in gas tungsten arc welding. The module has been designed to be totally integrated with Missouri's Vocational Instruction Management System. The basic principles involved in gas tungsten arc welding, supplies, and applications are covered. The materials included…

  19. Passive Visual Sensing in Automatic Arc Welding

    DEFF Research Database (Denmark)

    Liu, Jinchao

    For decades much work has been devoted to the research and development of automatic arc welding systems. However, it has remained a challenging problem. Besides the very complex arc welding process itself, the lack of ability to precisely sense the welding process, including the seam geometry...... industrial solutions for seam detection such as using laser scanners suer from several limitations. For instance, it must be positioned some distance ahead to the molten pool and may cause problem when dealing with shiny surfaces. Existing techniques for weld pool sensing mostly rely on auxiliary light...... on the weld pool and the nearby seam as the feedback to adjust the welding torch and/or welding parameters. It is an attractive idea from both academic and industrial point of view to develop a vision system without using any auxiliary light sources which can nevertheless extract relevant information. However...

  20. 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

  1. 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…

  2. Next generation high productivity submerged arc welding

    OpenAIRE

    LANGENOJA, MARKUS; Öhrvall Karlsson, Vincent

    2012-01-01

    The task of designing concepts for the next generation of submerged arc welding heads was given by ESAB. ESAB is a global company manufacturing welding equipment for a wide span of industries and uses. In October 2011, ESAB introduced a new technology called Integrated Cold Electrode™, abbreviated and trademarked as ICE™. ICE™ is a technique which utilizes three electrodes in a highly productive and stable process. The current state of the ICE™ technique focuses on welding thick plates with c...

  3. BASIC THEORY AND APPLICATIONS OF WELDING ARC SPECTRAL INFORMATION

    Institute of Scientific and Technical Information of China (English)

    LI Junyue; XUE Haitao; LI Huan; SONG Yonglun

    2007-01-01

    Welding arc spectral information is a rising welding Information source. In some occasion, it can reflect many physical phenomena of welding process and solve many problems that cannot be done with arc electric information, acoustic information and other arc information. It is of important significance in developing automatic control technique of welding process and other similar process. Many years study work on welding arc spectral information of the anthor are discussed from three aspects of theory, method and application. Basic theory, view and testing methods of welding arc spectral information has been put forward. In application aspects, many applied examples, for example, monitoring of harmful gases in arc (such as hydrogen and nitrogen) with the method of welding arc spectral information; welding arc spectral imaging of thc welding pool which is used in automatic seam tracking; controlling of welding droplet transfer with welding arc spectral information and so on, are introduced. Especially, the successful application in real time controlling of welding droplet transfer in pulsed GMAW is introduced too. These application examples show that the welding arc spectral information has great applied significance and development potentialities. These content will play an important role in applying and spreading welding arc spectral information technology.

  4. 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.

  5. 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 all laser parameters fixed. The welds were quality assessed and hardness measured transversely to the welding direction in the top, middle and root of the seam. In the seams welded by laser alone, hardness values between 275 and 304 HV1 were measured, about the double of the base material, 150 HV1...

  6. Arc-welding robot. 2; Yosetsu robot

    Energy Technology Data Exchange (ETDEWEB)

    Nishikawa, S. [Yaskawa Electric Corp., Kitakyushu (Japan)

    1995-02-01

    This is an introductory lecture on the selection and handling of arc-welding robot and was explained easily in Q and A style. This is the second of its series and extraction examples of Q and A are Q: type of stations for setting works, A: fixed, slide, inversion, rotary types and their combination, Q: station type for constructing a highly universal system for a wide variety of works, A: a highly universal robot was realized owing to external shaft control function. Recently, one robot can control a maximum of 21 shafts to cope with a variety of works, Q: off-line teaching for arc-welding robot, A: yes. It is available but does not spread as much as for spot since arc welding requires a high tracing accuracy. 12 figs.

  7. 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.

  8. 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)

  9. 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.

  10. 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.

  11. Gas Tungsten Arc Welding and Plasma Arc Cutting. Teacher Edition.

    Science.gov (United States)

    Fortney, Clarence; And Others

    This welding curriculum guide treats two topics in detail: the care of tungsten electrodes and the entire concept of contamination control and the hafnium electrode and its importance in dual-air cutting systems that use compressed shop air for plasma arc cutting activities. The guide contains three units of instruction that cover the following…

  12. The arc characteristic of ultrasonic assisted TIG welding

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Many applications of ultrasonic-assisted methods were used during metal solidification, but they could not be introduced into weld pool. In this paper, a way of ultrasonic assisted TIG welding is introduced. By directly imposed ultrasonic vibration on welding arc, the vibration interacts with arc plasma and passes to the weld pool. Measurement results show that arc pressure is significantly increased with the ultrasonic vibration and the arc pressure distribution models are changed. Bead-on-plate welding tests on SUS304 confirm that this technology can influence the style of metal melting and increase weld penetration depth.

  13. Advanced Control Methods for Optimization of Arc Welding

    DEFF Research Database (Denmark)

    Thomsen, J. S.

    Gas Metal Arc Welding (GMAW) is a proces used for joining pieces of metal. Probably, the GMAW process is the most successful and widely used welding method in the industry today. A key issue in welding is the quality of the welds produced. The quality of a weld is influenced by several factors...

  14. 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.

  15. 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...

  16. Robotic Variable Polarity Plasma Arc (VPPA) Welding

    Science.gov (United States)

    Jaffery, Waris S.

    1993-01-01

    The need for automated plasma welding was identified in the early stages of the Space Station Freedom Program (SSFP) because it requires approximately 1.3 miles of welding for assembly. As a result of the Variable Polarity Plasma Arc Welding (VPPAW) process's ability to make virtually defect-free welds in aluminum, it was chosen to fulfill the welding needs. Space Station Freedom will be constructed of 2219 aluminum utilizing the computer controlled VPPAW process. The 'Node Radial Docking Port', with it's saddle shaped weld path, has a constantly changing surface angle over 360 deg of the 282 inch weld. The automated robotic VPPAW process requires eight-axes of motion (six-axes of robot and two-axes of positioner movement). The robot control system is programmed to maintain Torch Center Point (TCP) orientation perpendicular to the part while the part positioner is tilted and rotated to maintain the vertical up orientation as required by the VPPAW process. The combined speed of the robot and the positioner are integrated to maintain a constant speed between the part and the torch. A laser-based vision sensor system has also been integrated to track the seam and map the surface of the profile during welding.

  17. 29 CFR 1926.351 - Arc welding and cutting.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Arc welding and cutting. 1926.351 Section 1926.351 Labor... (CONTINUED) SAFETY AND HEALTH REGULATIONS FOR CONSTRUCTION Welding and Cutting § 1926.351 Arc welding and cutting. (a) Manual electrode holders. (1) Only manual electrode holders which are specifically...

  18. 29 CFR 1915.56 - Arc welding and cutting.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Arc welding and cutting. 1915.56 Section 1915.56 Labor... (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS FOR SHIPYARD EMPLOYMENT Welding, Cutting and Heating § 1915.56 Arc welding and cutting. The provisions of this section shall apply to ship...

  19. 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.

  20. 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.

  1. 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.

  2. Exposure assessment of aluminum arc welding radiation.

    Science.gov (United States)

    Peng, Chiung-yu; Lan, Cheng-hang; Juang, Yow-jer; Tsao, Ta-ho; Dai, Yu-tung; Liu, Hung-hsin; Chen, Chiou-jong

    2007-10-01

    The purpose of this study is to evaluate the non-ionizing radiation (NIR) exposure, especially optical radiation levels, and potential health hazard from aluminum arc welding processes based on the American Conference of Governmental Industrial Hygienists (ACGIH) method. The irradiance from the optical radiation emissions can be calculated with various biological effective parameters [i.e., S(lambda), B(lambda), R(lambda)] for NIR hazard assessments. The aluminum arc welding processing scatters bright light with NIR emission including ultraviolet radiation (UVR), visible, and infrared spectra. The UVR effective irradiance (Eeff) has a mean value of 1,100 microW cm at 100 cm distance from the arc spot. The maximum allowance time (tmax) is 2.79 s according to the ACGIH guideline. Blue-light hazard effective irradiance (EBlue) has a mean value of 1840 microW cm (300-700 nm) at 100 cm with a tmax of 5.45 s exposure allowance. Retinal thermal hazard effective calculation shows mean values of 320 mW cm(-2) sr(-1) and 25.4 mW (cm-2) (380-875 nm) for LRetina (spectral radiance) and ERetina (spectral irradiance), respectively. From this study, the NIR measurement from welding optical radiation emissions has been established to evaluate separate types of hazards to the eye and skin simultaneously. The NIR exposure assessment can be applied to other optical emissions from industrial sources. The data from welding assessment strongly suggest employees involved in aluminum welding processing must be fitted with appropriate personal protection devices such as masks and gloves to prevent serious injuries of the skin and eyes upon intense optical exposure.

  3. Mathematical Modeling of Metal Active Gas (MAG) Arc Welding

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In the present paper, a numerical model for MAG (metal active gas) arc welding of thin plate has been developed. In MAG arc welding, the electrode wire is melted and supplied into the molten pool intermittently. Accordingly, it is assumed on the modeling that the thermal energy enters the base-plates through two following mechanisms, i.e., direct heating from arc plasma and “indirect” heating from the deposited metal. In the second part of the paper, MAG arc welding process is numerically analyzed by using the model, and the calculated weld bead dimension and surface profile have been compared with the experimental MAG welds on steel plate. As the result, it is made clear that the model is capable of predicting the bead profile of thin-plate MAG arc welding , including weld bead with undercutting.

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

    Institute of Scientific and Technical Information of China (English)

    郭振民; 陈善本; 邱涛; 吴林

    2003-01-01

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

  5. On arc efficiency in gas tungsten arc welding

    Directory of Open Access Journals (Sweden)

    Nils Stenbacka

    2013-12-01

    Full Text Available The aim of this study was to review the literature on published arc efficiency values for GTAW and, if possible, propose a narrower band. Articles between the years 1955 - 2011 have been found. Published arc efficiency values for GTAW DCEN show to lie on a wide range, between 0.36 to 0.90. Only a few studies covered DCEP - direct current electrode positive and AC current. Specific information about the reproducibility in calorimetric studies as well as in modeling and simulation studies (considering that both random and systematic errors are small was scarce. An estimate of the average arc efficiency value for GTAW DCEN indicates that it should be about 0.77. It indicates anyway that the GTAW process with DCEN is an efficient welding method. The arc efficiency is reduced when the arc length is increased. On the other hand, there are conflicting results in the literature as to the influence of arc current and travel speed.

  6. Thermocapillary and arc phenomena in stainless steel welds

    Energy Technology Data Exchange (ETDEWEB)

    Pierce, S.W.

    1993-10-01

    Goal was to study effect of power level and distribution on thermocapiilary-induced weld shape and of arc factors on weld shape. Thermocapillarity was apparent in both conduction mode EB welds and GTA welds, particularly in the former. A non-Gaussian arc distribution is suggested for accounting for the differences between the twoss processes. At higher current levels (200--300 A), plasma shear force also contributes to weld shape development. Evidence suggests that thermocapillary flow reversal is not a factor in normal GTA welds; EDB flow reversal occurs only at high power density levels where the keyhole mode is present.

  7. 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...

  8. Influence of Specific Features of Twin Arc Welding on Properties of Weld Joints

    Science.gov (United States)

    Sholokhov, M. A.; Melnikov, A. U.; Fiveyskiy, A. M.

    2016-04-01

    The present article covers the influence of standard and narrow gap twin arc welding on properties of weld joints from high-strength steels. While analyzing microsections we established that distribution of micro structure and phase terms, as well the distribution of micro-hardness, were more homogeneous under narrow gap twin arc welding.

  9. 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.

  10. Improving Weld Quality by Arc-Excited Ultrasonic Treatment

    Institute of Scientific and Technical Information of China (English)

    张春雷; 吴敏生; 杜敬磊

    2001-01-01

    Ultrasonic treatment of the solidifying metal is a promising method for improving the quality of fusion welding. A method to combine the ultrasonic waves to the welding process using arc-excited ultrasonic emission, called arc-ultrasonic, was high frequency modulation of the arc-plasma. The effects of arc-ultrasonic on the weld including the fusion zone, the partially melted zone and the heat-affected zone are described. The arc-ultrasonic energy changes the weld microstructure. In the fusion zone, the primary dendrite arm spacing decreases significantly and more acicular ferrite appears. In the partially melted zone, a large amount of fine grains appear. In the heat-affected zone, the width of the tempered zone increases with increasing modulation frequency and the microstructure is refined. The results show that arc-ultrasonic is a new and effective way for improving weld quality.

  11. Numerical analysis of dynamic variation of weld pool geometry in fully-penetrated TIG welding

    Institute of Scientific and Technical Information of China (English)

    Zhao Ming; Li Ruiying

    2008-01-01

    A mathematical model is developed for numerical analysis of thermal process in TIG welding with a moving arc, which is considered the double-elliptic distribution for both arc heat flux and arc pressure. An adjusting factor is introduced into the expression of arc pressure. The domain within which the arc heat flux is distributed non-symmetrically due to arc moving is selected appropriately, and three conditions for the domain to meet are described. The latent heat is taken into consideration by liquid fraction method. The dynamic development of weld pool geometry during TIG welding is analyzed numerically, and the effect of arc moving on the weld pool geometry is discussed. The experimental results show that the numerical analysis accuracy is obviously improved through taking the above-mentioned measures.

  12. Ultraviolet radiation emitted by CO(2) arc welding.

    Science.gov (United States)

    Okuno, T; Ojima, J; Saito, H

    2001-10-01

    The arcs associated with arc welding emit high levels of ultraviolet radiation (UVR), and this often causes acute injuries in the workplace, particularly photokeratoconjunctivitis. It is important to know the level of UVR emitted by arc welding under various conditions, as this information will help in evaluating potential UVR hazards in welding workplaces and taking protective measures against it. In this study, the ACGIH effective irradiance for UVR was measured experimentally for CO(2) arc welding in order to evaluate its UVR hazards. A welding robot was used in the experiment in order to realize reproducible and consistent welding operations. The effective irradiance at 1 m from the arc was in the range 0.28-7.85 W/m(2) (28-785 microW/cm(2)) under the study conditions. The corresponding permissible exposure time per day is only 4-100 s, suggesting that UVR from CO(2) arc welding is actually hazardous for the eye and skin. It was found that the effective irradiance is inversely proportional to the square of the distance from the arc, is strongly dependent on the direction of emission from the arc with a maximum at 50-60 degrees from the plate surface, and tends to increase with welding current.

  13. 29 CFR 1910.254 - Arc welding and cutting.

    Science.gov (United States)

    2010-07-01

    ... given to safety ground connections of portable machines. (4) Leaks. There shall be no leaks of cooling... Requirements for Electric Arc-Welding Apparatus, NEMA EW-1-1962, National Electrical Manufacturers Association or the Safety Standard for Transformer-Type Arc-Welding Machines, ANSI C33.2—1956,...

  14. Liquid Metal Oscillation and Arc Behaviour during Welding

    NARCIS (Netherlands)

    Yudodibroto, B.Y.B.

    2010-01-01

    The purpose of this research is to obtain insight into the oscillation behaviour of the liquid metal and the arc behaviour during GMA welding. Observations of the weld pool and the arc were undertaken by visual means using a high-speed video and by analysis of the voltage. To deal with the complex p

  15. Realizing precision pulse TIG welding with arc length control and visual image sensing based weld detection

    Institute of Scientific and Technical Information of China (English)

    孙振国; 陈念; 陈强

    2003-01-01

    Methods of arc length control and visual image based weld detection for precision pulse TIG welding were investigated. With a particular all-hardware circuit, arc voltage during peak current stage is sampled and integrated to indicate arc length, deviation of arc length and adjusting parameters are calculated and output to drive a step motor directly. According to the features of welding image grabbed with CCD camera, a special algorithm was developed to detect the central line of weld fast and accurately. Then an application system were established, whose static arc length error is ±0.1 mm with 20 A average current and 1 mm given arc length, static detection precision of weld is 0.01 mm, processing time of each image is less than 120 ms. Precision pulse TIG welding of some given thin stainless steel components with complicated curved surface was successfully realized.

  16. 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...... to weld pool tracking and the presented results verified its feasibility....

  17. Relationship between sound signal and weld pool status in plasma arc welding

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The sound features of the weld pool status in plasma arc welding were systematically investigated after the sound signal was collected with a microphone. The results show that it is difficult to extract information about the weld pool status directly in time domain although the sound signal varies with the weld pool behaviors to some extent. The frequency spectra of the sound signal contain plenty of information about the weld pool behaviors. It is shown from the analysis of the sound generation mechanism that the sound signal of plasma arc welding is mainly caused by the weld pool oscillation, the power source fluctuation and so on. RS algorithm is designed to determine the weld pool status, and it is able to offer the feedback information for the closed-loop control of the penetration quality of plasma arc welding.

  18. Effects of welding wire composition and welding process on the weld metal toughness of submerged arc welded pipeline steel

    Institute of Scientific and Technical Information of China (English)

    De-liang Ren; Fu-ren Xiao; Peng Tian; Xu Wang; Bo Liao

    2009-01-01

    The effects of alloying elements in welding wires and submerged arc welding process on the microstructures and low-temperature impact toughness of weld metals have been investigated.The results indicate that the optimal contents of alloying elements in welding wires can improve the low-temperature impact toughness of weld metals because the proentectoid ferrite and bainite formations can be suppressed,and the fraction of acicular ferrite increases.However,the contents of alloying elements need to vary along with the welding heat input.With the increase in welding heat input,the contents of alloying elements in welding wires need to be increased accordingly.The microstructures mainly consisting of acicular ferrite can be obtained in weld metals after four-wire submerged arc welding using the wires with a low carbon content and appropriate contents of Mn,Mo,Ti-B,Cu,Ni,and RE,resulting in the high low-temperature impact toughness of weld metals.

  19. Study on arc-ultrasonic TIG welding of titanium alloy

    Institute of Scientific and Technical Information of China (English)

    周荣林; 郭德伦; 李从卿; 张银根

    2004-01-01

    TC4 alloy was welded by conventional TIG welding and arc-ultrasonic TIG welding respectively. The microstructure of joint was analyzed by means of optical-microscope, scanning electron microscope in order to study the relationship between the macro-properties of joint and the microstructure. The results show that the joints were all welded successfully by conventional TIG welding and arc-ultrasonic TIG welding. With the increment of ultrasonic frequency and activated voltage, the width of joint became narrow step by step. The microstructure became more and more fine and was inclined to equiaxed crystal. Moreover, the dendrite depredation was not observed obviously. The properties of welded joint were improved markedly compared with that of conventional TIG welding.

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

    OpenAIRE

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

    2011-01-01

    Abstract Experimental and theoretical investigations on fibre-laser assisted plasma arc welding (LAPW) have been performed. Welding experiments were carried out on aluminium and steel sheets. In 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 case of aluminium weldin...

  1. 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.

  2. Computer Control For Gas/Tungsten-Arc Welding

    Science.gov (United States)

    Andersen, Kristinn; Springfield, James F.; Barnett, Robert J.; Cook, George E.

    1994-01-01

    Prototype computer-based feedback control system developed for use in gas/tungsten arc welding. Beyond improving welding technician's moment-to-moment general control of welding process, control system designed to assist technician in selecting appropriate welding-process parameters, and provide better automatic voltage control. Modular for ease of reconfiguration and upgrading. Modularity also reflected in software. Includes rack-mounted computer, based on VME bus, containing Intel 80286 and 80386 processors.

  3. Research on image segmentation of weld seam of oil derrick welded by arc welding robot

    Institute of Scientific and Technical Information of China (English)

    Cai Guangyu; Cui Shilin; Wu Changlin

    2009-01-01

    This paper puts forward a new method of PCNN (pulse-coupled neural networks) image segmentation, in which the binary matrix of the ignition frequency matrix is employed, for the first time, to act as the final result of image segmentation. It gives the principles of PCNN parameter selection under the guidance of this process. The new method reduces the dependence of PCNN on parameters, improves the effect of image segmentation, and produces good results after being applied to image recognition of weld seam of oil derrick welded by arc welding robot.

  4. 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.

  5. 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.

  6. BASIC THEORY AND METHOD OF WELDING ARC SPECTRAL INFORMATION

    Institute of Scientific and Technical Information of China (English)

    Li Junyue; Li Zhiyong; Li Huan; Xue Haitao

    2004-01-01

    Arc spectral information is a rising information source which can solve many problems that can not be done with arc electric information and other arc information.It is of important significance to develop automatic control technique of welding process.The basic theory and methods on it play an important role in expounding and applying arc spectral information.Using concerned equation in plasma physics and spectrum theory,a system of equations including 12 equations which serve as basic theory of arc spectral information is set up.Through analyzing of the 12 equations,a basic view that arc spectral information is the reflection of arc state and state variation,and is the most abundant information resource reflecting welding arc process is drawn.Furthermore,based on the basic theory,the basic methods of test and control of arc spectral information and points out some applications of it are discussesed.

  7. Investigation on the arc light spectrum in GTA welding

    Directory of Open Access Journals (Sweden)

    M.S. Węglowski

    2007-01-01

    Full Text Available Purpose: In the paper there are presented results of the influence of welding parameters on spectral intensity ofthe welding arc in the range of 340÷860 nm. The main goal was checking whether the visible radiation of thearc provides information which might prove to be useful in monitoring of the welding process, similarly as thesignals recorded in the electric circuit of the welding arc.Design/methodology/approach: The experimental station was designed and build. A spectrophotometer, in thevisible spectral range of 340 nm to 860 nm, was used. The investigations were conducted on the automated GTAwelding station. For each welding parameter the arc light spectrum was measuredFindings: Research results presented in this paper indicate that the welding arc radiation contains a number ofinformation concerning the course of the welding process. That signal is much more sensitive to the changes ofwelding conditions and should be used as a tool for monitoring of the TIG welding processResearch limitations/implications: The fiber spectrophotometer in the visible spectral range of 340 nm to860 nm is an expensive instrument and that fore it can be used only as a complementary tool in monitoring ofwelding processes.Practical implications: The gained experience allows directing farther research on the welding arc radiationphenomenon and the possibilities of using this signal for on-line monitoring of the welding process onautomated and robotized stands.This sensing system will be particularly attractive for welded structures manufacturing industry because it couldsignificantly reduce the cost for post weld analysis and repairsOriginality/value: Three fitting functions: Lorentz, Gauss and Voight were investigated as a means to simulatethe spectrum distribution. The mathematical-physical model of the arc light emission and neural networkswere compared

  8. Numerical analysis of transient keyhole shape in pulsed current plasma arc welding

    Institute of Scientific and Technical Information of China (English)

    孙俊华; 武传松

    2014-01-01

    Based on the characteristics of“one keyhole in a pulse”in pulsed current plasma arc welding (PAW),the transient variation process ofweld pool in a pulse cycle is simulated through the establishment ofcorresponding heat source model.And considering the effects ofgravitational force,plasma arc pressure and surface tension on the weld pool surface,the dynamic change features of the keyhole shape in a pulse cycle are calculated by using surface deformation equation. Experiments are conducted and validate that the calculated weld fusion line is in good agreement with the experimental results.

  9. 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.

  10. 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.

  11. Forming Completely Penetrated Welded T-joints when Pulsed Arc Welding

    Science.gov (United States)

    Krampit, N. Yu; Krampit, M. A.; Sapozhkov, A. S.

    2016-04-01

    The paper is focused on revealing the influence of welding parameters on weld formation when pulsed arc welding. As an experimental sample a T-joint over 10 mm was selected. Welding was carried out in flat position, which required no edge preparation but provided mono-directional guaranteed root penetration. The following parameters of welding were subjected to investigation: gap in the joint, wire feed rate and incline angles of the torch along and across the weld axis. Technological recommendations have been made with respect to pulsed arc welding; the cost price of product manufacturing can be reduced on their basis due to reduction of labor input required by machining, lowering consumption of welding materials and electric power.

  12. Comparison on welding mode characteristics of arc heat source for heat input control in hybrid welding of aluminum alloy

    Science.gov (United States)

    Song, Moo-Keun; Kim, Jong-Do; Oh, Jae-Hwan

    2015-03-01

    Presently in shipbuilding, transportation and aerospace industries, the potential to apply welding using laser and laser-arc hybrid heat sources is widely under research. This study has the purpose of comparing the weldability depending on the arc mode by varying the welding modes of arc heat sources in applying laser-arc hybrid welding to aluminum alloy and of implementing efficient hybrid welding while controlling heat input. In the experimental study, we found that hybrid welding using CMT mode produced deeper penetration and sounder bead surface than those characteristics produced during only laser welding, with less heat input compared to that required in pulsed arc mode.

  13. 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.

  14. Arc Behavior and Droplet Transfer of CWW CO2 Welding

    Institute of Scientific and Technical Information of China (English)

    Zhi-dong YANG; Chen-fu FANG; Yong CHEN; Guo-xiang XU; Qing-xian HU; Xiao-yan GU

    2016-01-01

    Cable-type welding wire (CWW)CO2 welding is an innovative process arc welding with high quality,high efficiency and energy saving,in which CWW is used as consumable electrode.The CWW is composed of seven wires with a diameter of 1.2 mm.One is in the center,while others uniformly distribute around it.The diameter of twisted wire is up to 3.6 mm,which can increase the deposition rate significantly.With continual wire-feeding and melting of CWW,the formed rotating arc improved welding quality obviously.The arc behavior and droplet transfer were ob-served by the electrical signal waveforms and corresponding synchronous images,based on the high speed digital camera and electrical signal system.The results showed that the shape of welding arc changed from bell arc to beam arc with the increase of welding parameter.The droplet transfer mode changed from repelled transfer,globular transfer to projected transfer in turn.Droplet transfer frequency increased from 18.17 Hz to 119.05 Hz,while the droplet diameter decreased from 1.5 times to 0.3 times of the CWW diameter.

  15. 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)

  16. 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...

  17. 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.

  18. 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.

  19. 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.

  20. Unique variable polarity plasma arc welding for space shuttle

    Science.gov (United States)

    Schwinghamer, R. J.

    1985-01-01

    Since the introduction of the Plasma Arc Torch in 1955 and subsequent to the work at Boeing in the 1960's, significant improvements crucial to success have been made in the Variable Polarity Plasma Arc (VPPA) Process at the Marshall Space Flight Center. Several very important advantages to this process are given, and the genesis of PA welding, the genesis of VPPA welding, special equiment requirements, weld property development, results with other aluminum alloys, and the eventual successful VPPA transition to production operations are discussed.

  1. Fuzzy logic control strategy for submerged arc automatic welding of digital controlling

    Institute of Scientific and Technical Information of China (English)

    He Kuanfang; Huang Shisheng; Zhou Yiqing; Wang Zhenmin

    2008-01-01

    A microcomputer control system based on 80C320 and a switching regulation of wire feeder were designed. A correction factor based double model fuzzy logic controller (FLC) was introduced to achieve welding digital and intellectualized control by means of wire feeding speed feedback. The controller has many functions such as keyboard input, light emitting diode (LED) display and real-time intellectualized control of welding process etc. The controlling performance influenced by the coefficient of correction function was discussed. It was concluded by the experiments the relation between the coefftcient of correction function and welding quality, when the coefficient of correction function is great, the dynamic character of controller is better, when the coefficient of correction function is small, the sensitivity character of controller is better. Experimental results also show that digital and fuzzy logic control method enable the improvement of appearance of weld and stability of welding process to be achieved in submerged arc automatic welding.

  2. Comparative study on interactions between laser and arc plasma during laser-GTA welding and laser-GMA welding

    Science.gov (United States)

    Chen, Minghua; Xu, Jiannan; Xin, Lijun; Zhao, Zuofu; Wu, Fufa

    2016-10-01

    This paper describes an investigation on differences in interactions between laser and arc plasma during laser-gas tungsten arc (LT) welding and laser-gas metal arc (LM) welding. The characteristics of LT heat source and LM heat source, such as plasma behavior, heat penetration ability and spectral information were comparably studied. Based on the plasma discharge theory, the interactions during plasma discharge were modeled and analyzed. Results show that in both LT and LM welding, coupling discharge between the laser keyhole plasma and arc happens, which strongly enhance the arc. But, the enhancing effect in LT welding is much more sensitive than that in LM welding when parameters are adjusted.

  3. Penetration control by weld pool resonance during gas tungsten arc welding

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Presents penetration control by weld pool resonance which occurs when the natural frequency of weld pool is equal to the frequency of sine wave current while the weld pool is excited into oscillation by superimposing sine wave current with definite frequency or regular fiequency on DC current, and experiments carried out on detecting resonance signals during both stationary and travelling arc welding with variant frequency pulse current, and concludes with ex perimental results that penetration control can be realized by weld pool resonance when welding speed is lower than 80mm/min, and this control method is applicable to welding thin (0.5 ~ 3.0 mm) plates of carbon steel, low alloy steel, high strength steel and superhigh strength steel, and suitable for alternating polarity welding of stainless steel, titanium alloy steel and aluminum alloy.

  4. A NEURAL NETWORK FOR WELD PENETRATION CONTROL IN GAS TUNGSTEN ARC WELDING

    Institute of Scientific and Technical Information of China (English)

    C.S. Wu; J.Q. Gao; Y.H. Zhao

    2006-01-01

    Realizing of weld penetration control in gas tungsten arc welding requires establishment of a model describing the relationship between the front-side geometrical parameters of weld pool and the back-side weld width with sufficient accuracy. A neural network model is developed to attain this aim. Welding experiments are conducted to obtain the training data set (including 973 groups of geometrical parameters of the weld pool and back-side weld width) and the verifying data set (108 groups). Two data sets are used for training and verifying the neural network, respectively.The testing results show that the model has sufficient accuracy and can meet the requirements of weld penetration control.

  5. FINITE DIFFERENCE SIMULATION OF LOW CARBON STEEL MANUAL ARC WELDING

    Directory of Open Access Journals (Sweden)

    Laith S Al-Khafagy

    2011-01-01

    Full Text Available This study discusses the evaluation and simulation of angular distortion in welding joints, and the ways of controlling and treating them, while welding plates of (low carbon steel type (A-283-Gr-C through using shielded metal arc welding. The value of this distortion is measured experimentally and the results are compared with the suggested finite difference method computer program. Time dependent temperature distributions are obtained using finite difference method. This distribution is used to obtain the shrinkage that causes the distortions accompanied with structural forces that act to modify these distortions. Results are compared with simple empirical models and experimental results. Different thickness of plates and welding parameters is manifested to illustrate its effect on angular distortions. Results revealed the more accurate results of finite difference method that match experimental results in comparison with empirical formulas. Welding parameters include number of passes, current, electrode type and geometry of the welding process.

  6. Vision-based weld seam tracking in gas metal arc welding

    Institute of Scientific and Technical Information of China (English)

    GAO Jinqiang; WU Chuansong; LIU Xizhang; XIA Dianxiu

    2007-01-01

    A low-cost visual sensmg system is developed to realize weld seam tracking in gas metal arc welding(GMAW).The system consists of a commercial CCD camera,narrow-band composite filter lens,an image capturing card,an industrial computer,a welding control unit,a GMAW power source,and a worktable.Images of root gap and its vicinity are captured in the GMAW welding process by the system.The captured images arc processed by an algorithm on the basis of the analysis of gray characteristics of the root gap to get the offsetting information between torch and root gap centerline.The offsetting information is then used to realize weld seam tracking in the GMAW process.Welding seam tracking experiment is conducted by a simple proportional(P)controller.The results show that tracking error is basically less than ±0.5 mm.

  7. Electromagnetic Characteristic of Twin-wire Indirect Arc Welding

    Institute of Scientific and Technical Information of China (English)

    SHI Chuanwei; ZOU Yong; ZOU Zengda; WU Dongting

    2015-01-01

    Traditional welding methods are limited in low heat input to workpiece and high welding wire melting rate. Twin-wire indirect arc(TWIA) welding is a new welding method characterized by high melting rate and low heat input. This method uses two wires:one connected to the negative electrode and another to the positive electrode of a direct-current(DC) power source. The workpiece is an independent, non-connected unit. A three dimensional finite element model of TWIA is devised. Electric and magnetic fields are calculated and their influence upon TWIA behavior and the welding process is discussed. The results show that with a 100 A welding current, the maximum temperature reached is 17 758 K, arc voltage is 14.646 V while maximum current density was 61 A/mm2 with a maximum Lorene force of 84.5mN. The above mentioned arc parameters near the cathode and anode regions are far higher than those in the arc column region. The Lorene force is the key reason for plasma velocity direction deviated and charged particles flowed in the channel formed by the cathode, anode and upper part of arc column regions. This led to most of the energy being supplied to the polar and upper part of arc column regions. The interaction between electric and magnetic fields is a major determinant in shaping TWIA as well as heat input on the workpiece. This is a first study of electromagnetic characteristics and their influences in the TWIA welding process, and it is significant in both a theoretical and practical sense.

  8. 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.

  9. Modeling cast IN-738 superalloy gas tungsten arc welds

    Energy Technology Data Exchange (ETDEWEB)

    Bonifaz, E.A. [Department of Mechanical and Manufacturing Engineering, University of Manitoba, E2-327F EITC, Winnipeg, Man., R3T 5V6 (Canada); Universidad San Francisco de Quito, Casilla Postal: 17-12-841 Circulo de Cumbaya, Quito (Ecuador)], E-mail: bonifaz@cc.umanitoba.ca; Richards, N.L. [Department of Mechanical and Manufacturing Engineering, University of Manitoba, E2-327F EITC, Winnipeg, Man., R3T 5V6 (Canada)], E-mail: nrichar@cc.umanitoba.ca

    2009-04-15

    A three-dimensional finite-element thermal model has been developed to generate weld profiles, and to analyze transient heat flow, thermal gradients and thermal cycles in cast IN-738 superalloy gas tungsten arc welds. Outputs of the model (cooling rates, the thermal gradient G and the growth rate R) were used to describe solidification structures found around the weld pool for three different welding speeds at constant heat input. Calculations around the weld pool indicate that the cooling rate increases from the fusion line to the centerline at all welding speeds. It was also observed that the cooling rate (G x R) and the ratio G/R fall with welding speed. For instance, as the welding speed is increased, the cooling rates at the centerline, fusion line and penetration depth decrease. Moreover, it was observed that as the power and welding speed both increase (but keeping the heat input constant), the weld pool becomes wider and more elongated, shifting from circular to elliptical shaped. The calculations were performed using ABAQUS FE code on the basis of a time-increment Lagrangian formulation. The heat source represented by a moving Gaussian power density distribution is applied over the top surface of the specimen during a period of time that depends on the welding speed. Temperature-dependent material properties and the effect of forced convection due to the flow of the shielding gas are included in the model. Numerically predicted sizes of the melt-pool zone and dendrite secondary arm spacing induced by the gas tungsten arc welding process are also given.

  10. 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.

  11. Study of issues in difficult-to-weld thick materials by hybrid laser arc welding

    Science.gov (United States)

    Mazar Atabaki, Mehdi

    There is a high interest for the high strength-to-weight ratio with good ductility for the welds of advanced alloys. The concern about the welding of thick materials (Advanced high strength steels (AHSS) and 5xxx and 6xxx series of aluminum alloys) has stimulated the development of manufacturing processes to overcome the associated issues. The need to weld the dissimilar materials (AHSS and aluminum alloys) is also required for some specific applications in different industries. Hence, the requirement in the development of a state-of-the-art welding procedure can be helpful to fulfill the constraints. Among the welding methods hybrid laser/arc welding (HLAW) has shown to be an effective method to join thick and difficult-to-weld materials. This process benefits from both advantages of the gas metal arc welding (GMAW) and laser welding processes. The interaction of the arc and laser can help to have enough penetration of weld in thick plates. However, as the welding of dissimilar aluminum alloys and steels is very difficult because of the formation of brittle intermetallics the present work proposed a procedure to effectively join the alloys. The reports showed that the explosively welded aluminum alloys to steels have the highest toughness, and that could be used as an "insert" (TRICLAD) for welding the thick plates of AHSS to aluminum alloys. Therefore, the HLAW of the TRICLAD-Flange side (Aluminum alloy (AA 5456)) to the Web side (Aluminum alloys (AA 6061 and AA 5456)) and the TRICLAD-Flange side (ASTM A516) to the Web side (AHSS) was studied in the present work. However, there are many issues related to HLAW of the dissimilar steels as well as dissimilar aluminum alloys that have to be resolved in order to obtain sound welds. To address the challenges, the most recent welding methods for joining aluminum alloys to steels were studied and the microstructural development, mechanical properties, and on-line monitoring of the welding processes were discussed as well

  12. 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.

  13. Numerical simulation of gas metal arc welding temperature field

    Institute of Scientific and Technical Information of China (English)

    Zheng Zhentai; Shan Ping; Hu Shengsun; Wei Xinwei; Yang Jinglei

    2006-01-01

    The infrared camera is used to investigate the temperature field of gas metal arc welding. The results show that the temperature distribution of weld pool and adjacent area appears cone shape. A new heat source model combined by Gaussian distribution heat source of the arc and conical distribution heat source of the droplet is set up based on the experimental results,and with the combined boundary conditions, the temperature field of gas metal arc welding is simulated using finite element method. According to the comparison between the results of experiment and simulation in temperature field shows that the new combined heat source model is more accurate and effective than the Gauss heat source model.

  14. Effects of process parameters on arc shape and penetration in twin-wire indirect arc welding

    Institute of Scientific and Technical Information of China (English)

    Shun-shan ZHANG; Mei-qing CAO; Dong-ting WU; Zeng-da ZOU

    2009-01-01

    In this study, the effects of variable parameters on arc shape and depth of penetration in twin-wire indirect arc gas shielded welding were investigated. The variation of arc shape caused by changes of the parameters was recorded by a high-speed camera,and the depths of penetration of specimen were measured after bead welding by an optical microscope. Experiments indicated that proper parameters give birth to a concentrated and compressed welcimg arc, which Would increase the depth of penetration as the incensement of the arc foice Several pnncipal parameters including toe distance ot twin wires intersecting point to base metal,the included angle,and the content of shielding gas were determined. The arc turned more concentrated and the depth of penetration increased obviously as the welding current increased,the arc turned brighter while unobvlous change of penetration occurred as the arc voltage increased,and the deepest penetration was obtained when the welding speed was 10.5 mm/s..

  15. Numerical Analysis of Two-Way Interaction between Weld-Pool and Arc for GTA Welding Process

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A mathematical model to describe the heat transfer and fluid flow in the mutually coupled weld pool and arc by an interactive free surface of the pool for a stationary gas tungsten arc welding (GTAW) is developed. The two sets of governing equations and auxiliary formulas, controlling the weld pool and plasma arc systems respectively, were solved by a finite difference method. A boundary-fitted coordinate system was adopted because the free surface has a curved and unknown shape during welding. The results of this work provide a fundamental basis for predicting the behavior of an integrated weld pool and arc system from first principles.

  16. 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.

  17. 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...

  18. Mathematical Model and the Simulation of Electrical Arc Welding as Moving Source in Protector Gas Welding

    Directory of Open Access Journals (Sweden)

    Lenuta Suciu

    2006-10-01

    Full Text Available The works presents the mathematical model of electrical arc welding, simulation of the electrical arc as a moving source with help programs software Ansys, passing through three stage of simulation: pre- processing, processing (solution and post-processing.

  19. Feature-based Design of Welded Structure for Robotic Arc Welding Off-line Programming

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Feature modeler of welded structure provides both 3D-geographical and non-geographical features for the off-line programming of arc welded robot. Welded structure is regarded as an assembly, the design of welded structure consists of three aspects: plane, joint, and groove design. Each aspect corresponds to a category of features. The plane features are defined by interactive feature definition. A method analogous to the “mating feature” is introduced to represent the joint features. Based on AutoCAD 2000, a B-rep solid modeler, a prototype system is implemented.

  20. Influence of metal vapour on arc temperatures in gas-metal arc welding: convection versus radiation

    Science.gov (United States)

    Murphy, Anthony B.

    2013-06-01

    The presence of metal vapour in gas-metal arc welding has been shown to have two strong effects on the arc plasma: a decrease in temperature throughout the arc, and the formation of a local temperature minimum near the arc axis. These effects have been attributed, on the basis of different computational models, to either the increased radiative emission associated with the presence of metal vapour in the arc plasma, or the influence of the metal vapour influx on convective flow in the arc. This question is investigated using a three-dimensional computational model in which the production and the transport of metal vapour are taken into account self-consistently. Parameters relevant to welding of thin sheets of aluminum are examined. For these conditions, it is found that the first effect (the decrease in temperature throughout the arc) is due to both the increased radiative emission and the influence of the metal vapour influx on flow. The second effect (the local temperature minimum, which in this case occurs just below the wire electrode) is a consequence of the influence of aluminum vapour produced from the wire electrode on flow in the arc. By examining published results and the energy balance in the plasma, it is shown that for welding of steel with higher arc currents, the increased radiative emission can lead to a local temperature minimum at a greater distance from the wire electrode.

  1. Study on heat source model in twin-arc GMAW with a common weld pool

    Institute of Scientific and Technical Information of China (English)

    Zhao Pengcheng; Wang Lulu; Liu Chunting; Huang Shisheng

    2009-01-01

    The heat input from arcs to weld pool in twin-arc gas metal arc welding (GMAW) with a common weld pool is investigated by high-speed photography. The characteristics of arc shapes and droplet transfer are studied and then the models for heat flux distribution on top surface of weld pool and enthalpy distribution of metal droplets transferred into weld pool are established. By using the model, 3-D geometries of weld pools in twin-arc GMAW with a common weld pool are predicted. Corresponding welding experiments on mild steel plates are carried out and the results indicate that the predicted shape of weld bead on cross section shows good agreement with measured one.

  2. Gas metal arc welding in refurbishment of cobalt base superalloys

    Science.gov (United States)

    Shahriary, M. S.; Miladi Gorji, Y.; Kolagar, A. M.

    2017-01-01

    Refurbishments of superalloys which are used in manufacturing gas turbine hot components usually consists of removing cracks and other defects by blending and then repair welding in order to reconstruct damaged area. In this study, the effects of welding parameters on repair of FSX-414 superalloy, as the most applicable cobalt base superalloy in order to manufacture gas turbine nozzles, by use of Gas Metal Arc Welding (GMAW) technic were investigated. Results then were compared by Gas Tungsten Arc Welding (GTAW). Metallographic and SEM studies of the microstructure of the weld and HAZ showed that there are no noticeable defects in the microstructure by use of GMAW. Also, chemical analysis and morphologies of carbide in both methods are similar. Hardness profile of the GM AW structure then also compared with GTAW and no noticeable difference was observed between the profiles. Also, proper tensile properties, compared with GTAW, can be achieved by use of optimum parameters that can be obtained by examining the current and welding speed. Tensile properties of optimized condition of the GMAW then were compared with GTAW. It was seen that the room and high temperature tensile properties of the GMAW structure is very similar and results confirmed that changing the technic did not have any significant influence on the properties.

  3. 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.

  4. Probing Pulsed Current Gas Metal Arc Welding for Modified 9Cr-1Mo Steel

    Science.gov (United States)

    Krishnan, S.; Kulkarni, D. V.; De, A.

    2015-04-01

    Modified 9Cr-1Mo steels are commonly welded using gas tungsten arc welding process for its superior control over the rate of heat input and vaporization loss of the key alloying elements although the rate electrode deposition remains restricted. Recent developments in pulsed current gas metal arc welding have significantly improved its ability to enhance the rate of electrode deposition with a controlled heat input rate while its application for welding of modified 9Cr-1Mo steels is scarce. The present work reports a detailed experimental study on the pulsed current gas metal arc welding of modified 9Cr-1Mo steels. The effect of the shielding gas, welding current, and speed on the weld bead profile, microstructure and mechanical properties are examined. The results show that the pulsed current gas metal arc welding with appropriate welding conditions can provide acceptable bead profile and mechanical properties in welds of modified 9Cr-1Mo steels.

  5. FE MODELING & ANALYSIS OF ARC WELDED T-JOINT

    Directory of Open Access Journals (Sweden)

    S.N.Pilare

    2012-06-01

    Full Text Available Arc welded structures are widely used in automobiles, constructions & power plants. As the main cause of weldment failure is design defect & overload, hence it is necessary to analyze the maximum stresses inthe weldment. In this paper an experimentation is carried out on welded T-joint to determine the breaking stress in the weldment. The FE analysis & analytical estimation of breaking stress is also carried out to verify the experimental results. The stress distribution along weld size & throat thickness is evaluated and also compared with reported findings. Further T-joint weld is analyzed under static tensile & bending load by varying the gap between parent plates with and without chamfer at weldment edges. The fatigue analysis under alternating tensile and bending load is also carried out and fatigue life of weldment is predicted with variation in the gap between parent plates.

  6. ARC welding method for bonding steel with aluminum

    Institute of Scientific and Technical Information of China (English)

    Zhenyang LU; Pengfei HUANG; Wenning GAO; Yan LI; Hanpeng ZHANG; Shuyan YIN

    2009-01-01

    When welding steel with aluminum, the appearance of intermetallic compounds of Fe and A1 will decrease tenacity and increase rigidity, which leads to bad joint performance. A new type of low energy input (LEI) welding technology is introduced which can be used to weld steel with aluminum. Using the technology, brazing was located on the steel side and arc fusion welding on the aluminum side. The less heat input reduces the thickness of intermetallic compounds to 3-4 μm. Tensile strength tests prove that the joint breaks at the heat-affected zone and the strength is higher than 70% of the aluminum's. Thus, the method can lead to a good performance joint.

  7. Optimization of Gas Metal Arc Welding Process Parameters

    Science.gov (United States)

    Kumar, Amit; Khurana, M. K.; Yadav, Pradeep K.

    2016-09-01

    This study presents the application of Taguchi method combined with grey relational analysis to optimize the process parameters of gas metal arc welding (GMAW) of AISI 1020 carbon steels for multiple quality characteristics (bead width, bead height, weld penetration and heat affected zone). An orthogonal array of L9 has been implemented to fabrication of joints. The experiments have been conducted according to the combination of voltage (V), current (A) and welding speed (Ws). The results revealed that the welding speed is most significant process parameter. By analyzing the grey relational grades, optimal parameters are obtained and significant factors are known using ANOVA analysis. The welding parameters such as speed, welding current and voltage have been optimized for material AISI 1020 using GMAW process. To fortify the robustness of experimental design, a confirmation test was performed at selected optimal process parameter setting. Observations from this method may be useful for automotive sub-assemblies, shipbuilding and vessel fabricators and operators to obtain optimal welding conditions.

  8. Physics characteristic of coupling arc of twin-tungsten TIG welding

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guang-jun; LENG Xue-song; WU Lin

    2006-01-01

    Twin-tungsten TIG welding was developed, in which two electrodes were placed in a single welding torch. In order to master this process, the arc physics characteristic was studied. The twin-tungsten coupling arc shape was observed by using CCD camera, and the arc pressure was measured. The results show that the coupling arc includes two arcs that pull each other according to Lorentz force and one big coupling arc is formed; the coupling arc pressure is much lower than that of conventional TIG arc. In the end, a simple welding experiment was carried out. This proves that stable welding process can be achieved by twin-tungsten TIG at higher current than that of conventional TIG because of its low arc pressure and the high efficiency welding is realized.

  9. Heat transfer modeling of double-side arc welding

    CERN Document Server

    Sun Jun Sheng; Zhang Yan Ming

    2002-01-01

    If a plasma arc and a TIG arc are connected in serial and with the plasma arc placed on the obverse side and the TIG arc on the opposite side of the workpiece, a special double-side arc welding (DSAW) system will be formed, in which the PAW current is forced to flow through the keyhole along the thickness direction so as to compensate the energy consumed for melting the workpiece and improve the penetration capacity of the PAW arc. By considering the mechanics factors which influence the DSAW pool geometric shape, the control equations of the pool surface deformation are derived, and the mathematics mode for DSAW heat transfer is established by using boundary-fitted non-orthogonal coordinate systems. With this model, the difference between DSAW and PAW heat transfer is analyzed and the reason for the increase of DSAW penetration is explained from the point of heat transfer. The welding process experiments show that calculated results are in good agreement with measured ones

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

    Energy Technology Data Exchange (ETDEWEB)

    Day, S D; Wong, F M G; Gordon, S R; Wong, L L; Rebak, R B

    2003-09-07

    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.

  11. 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%.

  12. Influence of arc pressure on the forming of molten pool in tungsten inert gas arc butt welding with micro gap for tantalum sheet

    Institute of Scientific and Technical Information of China (English)

    Zhou Fangming; Qian Yiyu

    2006-01-01

    Arc pressure is the key influencing factor to forming of molten pool.Countering the characteristic of tungsten inert gas arc welding with micro gap for tantalum sheet, according to the fundament of arc physics, a distribution model of arc pressure and forming mechanism of molten pool with micro butt gap are proposed, and the influences of arc pressure on forming of molten pool are discussed.Experimental researches for the dynamic formation process of weld molten pool by using high-speed vidicon camera show that when buttgap is appropriate, that is from 0.1 to 0.15 mm, molten metals formed on two workpiece uplift and growup first, then are fused and form uniform molten pool finally.

  13. Comparison of Welding Residual Stresses of Hybrid Laser-Arc Welding and Submerged Arc Welding in Offshore Steel Structures

    DEFF Research Database (Denmark)

    Andreassen, Michael Joachim; Yu, Zhenzhen; Liu, Stephen

    2016-01-01

    In the offshore industry, welding-induced distortion and tensile residual stresses have become a major concern in relation to the structural integrity of a welded structure. Particularly, the continuous increase in size of welded plates and joints needs special attention concerning welding induced...... residual stresses. These stresses have a negative impact on the integrity of the welded joint as they promote distortion, reduce fatigue life, and contribute to corrosion cracking and premature failure in the weld components. This paper deals with the influence and impact of welding method on the welding...... induced residual stresses. It is also investigated whether the assumption of residual stresses up to yield strength magnitude are present in welded structures as stated in the design guidelines. The fatigue strength for welded joints is based on this assumption. The two welding methods investigated...

  14. Mechanical Characteristics of Welded Joints of Aluminum Alloy 6061 T6 Formed by Arc and Friction Stir Welding

    Science.gov (United States)

    Astarita, A.; Squillace, A.; Nele, L.

    2016-01-01

    Butt welds formed by arc welding in inert gas with nonconsumable electrode (tungsten inert gas (TIG) welding) and by friction stir welding (FSW) from aluminum alloy AA6061 T6 are studied. Comparative analysis of the structures and mechanical properties of the welded joints is performed using the results of optical and electron microscopy, tensile tests, tests for residual bending ductility, and measurements of microhardness. The changes in the microstructure in different zones and the degrees of degradation of the mechanical properties after the welding are determined. It is shown that the size of the tool for the friction stir welding affects the properties of the welds. Quantitative results showing the relation between the microscopic behavior of the alloy and the welding-induced changes in the microstructure are obtained. Friction stir welding is shown to provide higher properties of the welds.

  15. Effect of pulsed current and post weld aging treatment on tensile properties of argon arc welded high strength aluminium alloy

    Energy Technology Data Exchange (ETDEWEB)

    Balasubramanian, V. [Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar, Tamil Nadu 608002 (India)], E-mail: visvabalu@yahoo.com; Ravisankar, V. [Department of Manufacturing Engineering, Annamalai University, Annamalai Nagar, Tamil Nadu 608002 (India); Reddy, G. Madhusudhan [Metal Joining Section, Defence Metallurgical Research Laboratory, Kanchanbag (P.O.), Hyderabad 560058 (India)

    2007-06-25

    This paper reveals the effect of pulsed current and post weld aging treatment on tensile properties of argon arc welded AA7075 aluminium alloy. This alloy has gathered wide acceptance in the fabrication of light weight structures requiring high strength-to-weight ratio, such as transportable bridge girders, military vehicles, road tankers and railway transport systems. The preferred welding processes of high strength aluminium alloy are frequently gas tungsten arc welding (GTAW) process and gas metal arc welding (GMAW) process due to their comparatively easier applicability and better economy. Weld fusion zones typically exhibit coarse columnar grains because of the prevailing thermal conditions during weld metal solidification. This often results inferior weld mechanical properties and poor resistance to hot cracking. In this investigation, an attempt has been made to refine the fusion zone grains by applying pulsed current welding technique. Four different welding techniques have been used to fabricate the joints and they are: (i) continuous current GTAW (CCGTAW), (ii) pulsed current GTAW (PCGTAW), (iii) continuous current GMAW (CCGMAW) and (iv) pulsed current GMAW (PCGMAW) processes. As welded joint strength is much lower than the base metal strength and hence, a simple aging treatment has been given to improve the tensile strength of the joints. Current pulsing leads to relatively finer and more equi-axed grain structure in GTA and GMA welds. In contrast, conventional continuous current welding resulted in predominantly columnar grain structures. Post weld aging treatment is accompanied by an increase in tensile strength and tensile ductility.

  16. 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.

  17. 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…

  18. Gas-tungsten arc welding of aluminum alloys

    Science.gov (United States)

    Frye, Lowell D.

    1984-01-01

    A gas-tungsten arc welding method for joining together structures formed of aluminum alloy with these structures disposed contiguously to a heat-damagable substrate of a metal dissimilar to the aluminum alloy. The method of the present invention is practiced by diamond machining the fay surfaces of the aluminum alloy structures to provide a mirror finish thereon having a surface roughness in the order of about one microinch. The fay surfaces are aligned and heated sufficiently by the tungsten electrode to fuse the aluminum alloy contiguous to the fay surfaces to effect the weld joint. The heat input used to provide an oxide-free weld is significantly less than that required if the fay surfaces were prepared by using conventional chemical and mechanical practices.

  19. Influence of Welding Current and Focal Position on the Resonant Absorption of Laser Radiation in a TIG Welding Arc

    Science.gov (United States)

    Emde, B.; Huse, M.; Hermsdorf, J.; Kaierle, S.; Wesling, V.; Overmeyer, L.

    The work presents the influence of welding current and focal position on the resonant absorption of diode laser radiation in a TIG welding arc. The laser beam is guided perpendicular to the electrical arc to avoid an interaction with the electrodes. Laser power measurements have shown a reduction of the measured laser power up to 18% after passing the electrical arc. This reduction results from the interaction of argon shielding gas atoms and laser radiation at 810.4 nm and 811.5 nm. The interaction is strongly affected by the adjusted welding current and the adjustment of the laser beam and the electrical arc. Lowering the welding current or shifting the laser beam out of the centerline of the electrical arc reduces the ionization probability. An increased ionization is necessary to decrease the resistance of the electrical arc.

  20. 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.

  1. An Electrochemical Evaluation on the Corrosion of Weld Zone in Cold Arc Welding of the Cast Iron

    Energy Technology Data Exchange (ETDEWEB)

    Moon, Kyung Man; Lee, Myung Hoon; Kim, Ki Joon [Korea Maritime University, Busan (Korea, Republic of); Kim, Jin Gyeong [Korea Institute of Marine and Frsheries Technology, Busan (Korea, Republic of)

    2008-04-15

    Cold arc welding of cast iron has been widely used with repair welding of metal structures. However its welding is often resulted in the galvanic corrosion between weld metal zone and heat affected zone(HAZ) due to increasing of hardness. In this study, corrosion properties such as hardness, corrosion potential, surface microstructures, and variation of corrosion current density of welding zone with parameters of used electrodes for cast iron welding were investigated with an electrochemical evaluation. Hardness of HAZ showed the highest value compared to other welding zone regardless of kinds of used electrodes for cast iron welding. And its corrosion potential was also shifted to more negative direction than other welding zone. In addition, corrosion current density of WM in polarization cures was qualitatively smaller than that of HAZ. Therefore galvanic corrosion may be apparently observed at HAZ. However galvanic corrosion may be somewhat controlled by using an optimum welding electrode.

  2. 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.

  3. 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.

  4. 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.

  5. Laser guided and stabilized gas metal arc welding processes (LGS-GMA)

    Science.gov (United States)

    Hermsdorf, Jörg; Barroi, Alexander; Kaierle, Stefan; Overmeyer, Ludger

    2013-05-01

    The demands of the industry are cheap and fast production of highly sophisticated parts without compromises in product quality. To realize this requirement, we have developed a laser guided and stabilized gas metal arc process (LGS-GMA welding). The new welding process is based on a gas metal arc process using low power laser radiation for stabilization. The laser stabilization of gas metal arcs welding is applied to joint welding and cladding. With only 400 W laser power and a focal spot of 1.6 mm the laser radiation is mainly interacting with the arc plasma in order to guide and stabilize it. In joint welding up to 100% increase in welding speed is possible, at equal penetration depth. The guidance effect also enables the process to weld in challenging situations like different sheet thicknesses. Used for cladding, the enhanced process stability allows low penetration depth with dilutions of only 3%. Coatings with up to 63 HRC were achieved.

  6. Artificial Optical Radiation photobiological hazards in arc welding.

    Science.gov (United States)

    Gourzoulidis, G A; Achtipis, A; Topalis, F V; Kazasidis, M E; Pantelis, D; Markoulis, A; Kappas, C; Bourousis, C A

    2016-08-01

    Occupational Health and Safety (OHS) is associated with crucial social, economic, cultural and technical issues. A highly specialized OHS sector deals with the photobiological hazards from artificial optical radiation (AOR), which is divided into visible light, UV and IR emitted during various activities and which is legally covered by European Directive 2006/25/EC. Among the enormous amount of sources emitting AOR, the most important non-coherent ones to consider for health effects to the whole optical range, are arcs created during metal welding. This survey presents the effort to assess the complicated exposure limits of the Directive in the controlled environment of a welding laboratory. Sensors covering the UV and blue light range were set to measure typical welding procedures reproduced in the laboratory. Initial results, apart from apparently justifying the use of Personal Protective Equipment (PPE) due to even subsecond overexposures measured, also set the basis to evaluate PPE's properties and support an integrated risk assessment of the complex welding environment. These results can also improve workers' and employer's information and training about radiation hazards, which is a crucial OHS demand.

  7. 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.

  8. Analysis of keyhole geometry in plasma arc welding

    Institute of Scientific and Technical Information of China (English)

    Hu Qingxian; Wu Chuansong

    2006-01-01

    The key problem for numerical simulation of plasma arc welding (PAW) process is to develop a suitable and adaptive volumetric heat source mode which reflects the physical characteristics of keyhole PAW. To this end, the keyhole geometry under different PAW process conditions must be predicted. In this paper, a mathematical model for determining the keyhole shape is developed with considering the mass and momentum conservation of the in-keyhole plasma jet as well as the pressure equilibrium at the plasma jet/liquid metal boundary. A suitable heat source model related to the keyhole shape is applied to the calculation of PAW weld dimensions. The predicted results are in good agreement with the experimental ones.

  9. 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.

  10. FORWARD KINEMATICS ANALYSIS OF 6-DOF ARC WELDING ROBOT

    Directory of Open Access Journals (Sweden)

    DR. ANURAG VERMA

    2010-09-01

    Full Text Available The forward kinematics problem is concerned with the relationship between the individual joints of the robot manipulator and the position and orientation of the tool or end-effector. Stated more formally, the forward kinematics problem is to determine the position and orientation of the end-effector, given the values for the jointvariables of the robot. Present work is an attempt to develop kinematic model of a 6 DOF robot which is used for arc welding operation. Developed model will determine position and orientation of the end-effector with respect to various joint variables. The said analysis is carried out in Matlab.

  11. Specular reflection based sensing surface deformation of gas tungsten arc weld pool

    Institute of Scientific and Technical Information of China (English)

    Zhang Shiliang; Gao Jinqiang; Wu Chuansong; Zhang Yuming

    2007-01-01

    A sensing system is developed to measure the weld pool boundary and pool surface deformation in gas tungsten arc welding. LaserStrobe technique is used to eliminate the strong arc light interference, and specular reflection from the pool surface is sensed to describe the relation between the deformed stripes and pool surface depression. Clear images of both the pool boundary and the deformed stripes edges are obtained during gas tungsten arc welding process, which lays foundation for real-time monitoring the pool surface depression and weld penetration.

  12. Modeling of Fume Formation from Shielded Metal Arc Welding Process

    Science.gov (United States)

    Sivapirakasam, S. P.; Mohan, Sreejith; Santhosh Kumar, M. C.; Surianarayanan, M.

    2017-01-01

    In this study, a semi-empirical model of fume formation rate (FFR) from a shielded metal arc welding (SMAW) process has been developed. The model was developed for a DC electrode positive (DCEP) operation and involves the calculations of droplet temperature, surface area of the droplet, and partial vapor pressures of the constituents of the droplet to predict the FFR. The model was further extended for predicting FFR from nano-coated electrodes. The model estimates the FFR for Fe and Mn assuming constant proportion of other elements in the electrode. Fe FFR was overestimated, while Mn FFR was underestimated. The contribution of spatters and other mechanism in the arc responsible for fume formation were neglected. A good positive correlation was obtained between the predicted and experimental FFR values which highlighted the usefulness of the model.

  13. Modeling of Fume Formation from Shielded Metal Arc Welding Process

    Science.gov (United States)

    Sivapirakasam, S. P.; Mohan, Sreejith; Santhosh Kumar, M. C.; Surianarayanan, M.

    2017-04-01

    In this study, a semi-empirical model of fume formation rate (FFR) from a shielded metal arc welding (SMAW) process has been developed. The model was developed for a DC electrode positive (DCEP) operation and involves the calculations of droplet temperature, surface area of the droplet, and partial vapor pressures of the constituents of the droplet to predict the FFR. The model was further extended for predicting FFR from nano-coated electrodes. The model estimates the FFR for Fe and Mn assuming constant proportion of other elements in the electrode. Fe FFR was overestimated, while Mn FFR was underestimated. The contribution of spatters and other mechanism in the arc responsible for fume formation were neglected. A good positive correlation was obtained between the predicted and experimental FFR values which highlighted the usefulness of the model.

  14. 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....

  15. 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.

  16. 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.

  17. Numerical simulation and experimental validation of arc welding of DMR-249A steel

    OpenAIRE

    2016-01-01

    The thermo-mechanical attributes of DMR-249A steel weld joints manufactured by shielded metal arc welding (SMAW) and activated gas tungsten arc welding (A-GTAW) processes were studied using Finite Element Model (FEM) simulation. The thermal gradients and residual stresses were analyzed with SYSWELD software using double ellipsoidal heat source distribution model. The numerically estimated temperature distribution was validated with online temperature measurements using thermocouples. The pred...

  18. FLUXES FOR MECHANIZED ELECTRIC WELDING,

    Science.gov (United States)

    WELDING FLUXES, WELDING ), (* WELDING , WELDING FLUXES), ARC WELDING , WELDS, STABILITY, POROSITY, WELDING RODS, STEEL, CERAMIC MATERIALS, FLUXES(FUSION), TITANIUM ALLOYS, ALUMINUM ALLOYS, COPPER ALLOYS, ELECTRODEPOSITION

  19. Ballistic-Failure Mechanisms in Gas Metal Arc Welds of Mil A46100 Armor-Grade Steel: A Computational Investigation

    Science.gov (United States)

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

    2014-09-01

    In our recent work, a multi-physics computational model for the conventional gas metal arc welding (GMAW) joining process was introduced. The model is of a modular type and comprises five modules, each designed to handle a specific aspect of the GMAW process, i.e.: (i) electro-dynamics of the welding-gun; (ii) radiation-/convection-controlled heat transfer from the electric-arc to the workpiece and mass transfer from the filler-metal consumable electrode to the weld; (iii) prediction of the temporal evolution and the spatial distribution of thermal and mechanical fields within the weld region during the GMAW joining process; (iv) the resulting temporal evolution and spatial distribution of the material microstructure throughout the weld region; and (v) spatial distribution of the as-welded material mechanical properties. In the present work, the GMAW process model has been upgraded with respect to its predictive capabilities regarding the spatial distribution of the mechanical properties controlling the ballistic-limit (i.e., penetration-resistance) of the weld. The model is upgraded through the introduction of the sixth module in the present work in recognition of the fact that in thick steel GMAW weldments, the overall ballistic performance of the armor may become controlled by the (often inferior) ballistic limits of its weld (fusion and heat-affected) zones. To demonstrate the utility of the upgraded GMAW process model, it is next applied to the case of butt-welding of a prototypical high-hardness armor-grade martensitic steel, MIL A46100. The model predictions concerning 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 prior observations and general expectations.

  20. Gas Tungsten Arc Welding and Plasma Arc Cutting. Teacher Edition [and] Student Edition [and] Student Workbook. Second Edition.

    Science.gov (United States)

    Harper, Eddie; Knapp, John

    This packet of instructional materials for a gas tungsten arc welding (GTAW) and plasma arc cutting course is comprised of a teacher edition, student edition, and student workbook. The teacher edition consists of introductory pages and teacher pages. Introductory pages include training and competency profile, state duty/task crosswalk,…

  1. TRANSIENT FINITE ELEMENT SIMULATION AND MICROSTRUCTURE EVOLUTION OF AA2219 WELD JOINT USING GAS TUNGSTEN ARC WELDING PROCESS

    Directory of Open Access Journals (Sweden)

    Sivaraman Arunkumar

    2016-09-01

    Full Text Available In this study we focus on finite element simulation of gas tungsten arc welding (GTAW of AA2219 aluminum alloy and the behavioral of the microstructure before and after weld. The simulations were performed using commercial COMSOL Multiphysics software. The thermal history of the weld region was studied by initially developed mathematical model. A sweep type meshing was used and transient analysis was performed for one welding cycle. The highest temperature noted was 3568 °C during welding. The welding operation was performed on 200×100×25 mm plates. Through metallurgical characterization, it was observed that a fair copper rich cellular (CRC network existed in the weld region. A small amount of intermetallic compounds like Al2Cu is observed through the XRD pattern.

  2. 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.

  3. 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.

  4. Dynamics of space welding impact and corresponding safety welding study.

    Science.gov (United States)

    Fragomeni, James M; Nunes, Arthur C

    2004-03-01

    This study was undertaken in order to be sure that no hazard would exist from impingement of hot molten metal particle detachments upon an astronauts space suit during any future electron beam welding exercises or experiments. The conditions under which molten metal detachments might occur in a space welding environment were analyzed. The safety issue is important during welding with regards to potential molten metal detachments from the weld pool and cold filler wire during electron beam welding in space. Theoretical models were developed to predict the possibility and size of the molten metal detachment hazards during the electron beam welding exercises at low earth orbit. Some possible ways of obtaining molten metal drop detachments would include an impulse force, or bump, to the weld sample, cut surface, or filler wire. Theoretical models were determined for these detachment concerns from principles of impact and kinetic energies, surface tension, drop geometry, surface energies, and particle dynamics. A weld pool detachment parameter for specifying the conditions for metal weld pool detachment by impact was derived and correlated to the experimental results. The experimental results were for the most part consistent with the theoretical analysis and predictions.

  5. 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)

  6. 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.

  7. The alternate wire-feed control in the automatic CO2 arc welding

    Institute of Scientific and Technical Information of China (English)

    卢亚静; 胡绳荪; 易小林; 单平

    2004-01-01

    In the automatic CO2 arc welding, the alteration of the vertical distance between the welding torch and the workpiece has a strong effect on the welding parameters such as welding current and voltage, with the result that the appearance and quality of weld are not steady. To weaken the influence of the distance alteration, a method is put forward in the paper. The method is that the alternate wire-feed control is used for compensating the welding current. On the basis of theoretical analysis, a static numerical model for alternate wire-feed control is established. The experiments show that the model-based regulation of the wire feed rate can compensate the welding current and ensure the appearance of weld. When the alteration of vertical distance between the torch and the workpiece is greater, not only is the wire feed rate regulated, but the output voltage of the power source is adjusted to ensure the appearance and quality of weld.

  8. 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.

  9. Evaluation model for process stability of short-circuiting arc welding

    Institute of Scientific and Technical Information of China (English)

    Cai Yan; Yang Hailan; Hua Xueming; Wu Yixiong

    2008-01-01

    stability of welding process is the prerequisite and assurance for ideal joint. The structure of stability model and its optimization are the key to on-line evaluation technology of arc welding. Characteristic parameters are extracted from the single transfer period while variation coefficients of the characteristic parameters are concerned for whole welding process of continuous drop transfer. Based on the characteristic parameters and their variation coefficients, stability model of short-circuit arc welding process is established by partial-least-square regression (PLSR) that can overcome multicollinearity of input parameters. The experiment results show that this model can meet the requirement of accuracy.

  10. 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.

  11. Arc sensing system for automatic weld seam tracking (II) ——Signal processing

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Due to violent disturbance of the welding arc, signal processingis the key problem of application of the sensor. By means of the new technique the arc sensor can recognize not only V-groove but also lap joint and butt joint. The sensor has good recognition ability even for welding process with very large current disturbance, e.g. pulsed arc and short circuit welding process, etc. The proposed technique is developed on the basis of modern digital filtering theory and mathematic transformation of the signals from time domain into frequency domain.

  12. 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.

  13. Distribution of Argon Arc Contaminated with Nitrogen as Function of Frequency in Pulsed TIG Welding

    Science.gov (United States)

    Takahashi, Hiroki; Tanaka, Tatsuro; Yamamoto, Shinji; Iwao, Toru

    2016-09-01

    TIG arc welding is the high-quality and much applicable material joining technology. However, the current has to be small because the cathode melting should be prevented. In this case, the heat input to the welding pool becomes low, then, the welding defect sometimes occurs. The pulsed TIG arc welding is used to improve this disadvantage This welding can be controlled by some current parameters such as frequency However, few report has reported the distribution of argon arc contaminated with nitrogen It is important to prevent the contamination of nitrogen because the melting depth increases in order to prevent the welding defects. In this paper, the distribution of argon arc contaminated as function of frequency with nitrogen in pulsed TIG welding is elucidated. The nitrogen concentration, the radial flow velocity, the arc temperature were calculated using the EMTF simulation when the time reached at the base current. As a result, the nitrogen concentration into the arc became low with increasing the frequency The diffusion coefficient decreased because of the decrement of temperature over 4000 K. In this case, the nitrogen concentration became low near the anode. Therefore, the nitrogen concentration became low because the frequency is high.

  14. PENETRATION QUALITY EVALUATION IN ROBOTIZED ARC WELDING BASED ON SUPPORT VECTOR MACHINE

    Institute of Scientific and Technical Information of China (English)

    Ye Feng; Song Yonglun; Li Di; Lai Yizong

    2003-01-01

    A quality monitoring method by means of support vector machines (SVM) for robotized gas metal arc welding (GMAW) is introduced. Through the feature extraction of the welding process signal,a SVM classifier is constructed to establish the relationship between the feature of process parameters and the quality of weld penetration. Under the samples obtained from auto parts welding production line, the learning machine with a radial basis function kernel shows good performance. And this method can be feasible to identify defect online in welding production.

  15. Sensing controlled pulse key-holing condition in plasma arc welding

    Institute of Scientific and Technical Information of China (English)

    JIA Chuan-bao; WU Chuan-song; ZHANG Yu-ming

    2009-01-01

    According to the strategy of controlled pulse key-holing, a new sensing and control system was developed for monitoring and controlling the keyhole condition during plasma arc welding (PAW). Through sensing and processing the efflux plasma voltage signals, the quantitative relationship among the welding current, efflux plasma voltage and backside weld width of the weld was established. PAW experiments show that the efflux plasma voltage can reflect the state of keyhole and backside weld width accurately. The closed-loop control tests validate the stability and reliability of the developed keyhole PAW system.

  16. 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.

  17. Predicting of bead undercut defects in high-speed gas metal arc welding (GMAW)

    Institute of Scientific and Technical Information of China (English)

    Wen-jing XU; Chuan-song WU; De-gang ZOU

    2008-01-01

    In the gas metal arc welding (GMAW) process, when the welding speed reaches a certain threshold, there will be an onset of weld bead undercut defects which limit the further increase of the welding speed. Establishing a mathematical model for high-speed GMAW to predict the tendency of bead undercuts is of great significance to pre-vent such defects. Under the action of various forces, the transferred metal from filler wire to the weld pool, and the geometry and dimension of the pool itself decide if the bead undercut occurs or not. The previous model simpli-fied the pool shape too much. In this paper, based on the actual weld pool geometry and dimension calculated from a numerical model, a hydrostatic model for liquid metal surface is used to study the onset of bead undercut defects in the high-speed welding process and the effects of dif-ferent welding parameters on the bead undercut tendency.

  18. 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.

  19. Double-sided gas tungsten arc welding process on TC4 titanium alloy

    Institute of Scientific and Technical Information of China (English)

    GAO Hong-ming; BAI Yan; YANG Tian-dong

    2005-01-01

    TC4 titanium alloy was welded by double-sided gas tungsten arc welding(GTAW) process in comparison with conventional GTAW process, the microstructure and mechanical performance of weld were also studied. The results indicate that double-sided GTAW is superior over regular single-sided GTAW on the aspects of increasing penetration, reducing welding deformation and improving welding efficiency. Good weld joint was obtained, which can reach 96.14% tensile strength and 70.85 % elongation percentage of the base metal. The grains in heat-affected zone(HAZ) are thin and equiaxed and the degree of grain coarsening increases as one moves to the weld center line,and the interior of grains are α and α' structures. The coarse columned and equiaxed grains, which interlace martensitic structures α' and acicular α structures, are observed in weld zone. The fracture mode is ductile fracture.

  20. 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.

  1. ELECTRIC ARC WELDING DEPOSITION OF METALLIC SURFACES BY VIBRATING ELECTRODE IN PROTECTIVE GAS MEDIUM

    OpenAIRE

    N. Spiridonov; A. Кudina; V. Кurash

    2013-01-01

    The paper presents methods for obtaining qualitative metallic surfaces by electric arc welding deposition while using consumable electrode in a protective gas medium and executing regularized drop transfer of electrode metal. The drop transfer efficiency of electrode metal and productivity of welding deposition are significantly increased due to excitation of lateral vibrations in the consumable electrode with preset amplitude. The paper describes a method and a device for welding deposition ...

  2. Finite element analysis of keyhole plasma arc welding based on an adaptive heat source mode

    Institute of Scientific and Technical Information of China (English)

    Hu Qingxian; Wu Chuansong; Zhang Yuming

    2007-01-01

    An adaptive heat source mode is proposed to account for the keyhole effect and the characteristics of volumetric distribution along the direction of the workpiece thickness. Finite element analysis of the temperature field in keyhole plasma arc welding is conducted and the weld geometry is obtained. The predicted results are in agreement with the measured ones.

  3. Description and Preliminary Training Evaluation of an Arc Welding Simulator. Research Report SRR 73-23.

    Science.gov (United States)

    Abrams, Macy L.; And Others

    A prototype arc welding training simulator was designed to provide immediate, discriminative feedback and the capacity for concentrated practice. Two randomly selected groups of welding trainees were compared to evaluate the simulator, one group being trained using the simulator and the other using conventional practice. Preliminary data indicated…

  4. The radiological risk in arc welding; El riesgo radiologico en la soldadura por arco

    Energy Technology Data Exchange (ETDEWEB)

    Alegria, N.; Campos, M.; Carrion, A.; Herranz, M.; Idoeta, R.; Legarda, F.; Nunez-Lagos, R.; Perez, C.; Rodriguez, S.; Rozas, S.; Sanchez, P.

    2011-07-01

    We present the current status of a project funded by the Nuclear Safety Council, for the study of the potential radiological risk in arc welding. In the coating of filler material of the electrodes and the soul of the continuous tubular wire welding material are located NORM who present a radioactive activity.

  5. The influence of arc plasma parameters on the form of a welding pool

    Science.gov (United States)

    Frolov, V. Ya.; Toropchin, A. I.

    2015-07-01

    The influence of the Marangoni force on the form of a welding pool has been considered. Results of computer simulation of the processes of welding arc generation with a non-consumable tungsten electrode in inert gas are shown. The experimental results are reported and comparatively analyzed. The calculations were carried out in a package of applied programs at various currents.

  6. 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.

  7. [Arc spectrum diagnostic and heat coupling mechanism analysis of double wire pulsed MIG welding].

    Science.gov (United States)

    Liu, Yong-qiang; Li, Huan; Yang, Li-jun; Zheng, Kai; Gao, Ying

    2015-01-01

    A double wire pulsed MIG welding test system was built in the present paper, in order to analyze the heat-coupling mechanism of double wire pulsed MIG welding, and study are temperature field. Spectroscopic technique was used in diagnostic analysis of the are, plasma radiation was collected by using hollow probe method to obtain the arc plasma optical signal The electron temperature of double wire pulsed MIG welding arc plasma was calculated by using Boltzmann diagram method, the electron temperature distribution was obtained, a comprehensive analysis of the arc was conducted combined with the high speed camera technology and acquisition means of electricity signal. The innovation of this paper is the combination of high-speed camera image information of are and optical signal of arc plasma to analyze the coupling mechanism for dual arc, and a more intuitive analysis for are temperature field was conducted. The test results showed that a push-pull output was achieved and droplet transfer mode was a drop in a pulse in the welding process; Two arcs attracted each other under the action of a magnetic field, and shifted to the center of the arc in welding process, so a new heat center was formed at the geometric center of the double arc, and flowing up phenomenon occurred on the arc; Dual arc electronic temperature showed an inverted V-shaped distribution overall, and at the geometric center of the double arc, the arc electron temperature at 3 mm off the workpiece surface was the highest, which was 16,887.66 K, about 4,900 K higher than the lowest temperature 11,963.63 K.

  8. 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.

  9. 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)

  10. ARC+(Registered Trademark) and ARC PC Welding Simulators: Teach Welders with Virtual Interactive 3D Technologies

    Science.gov (United States)

    Choquet, Claude

    2011-01-01

    123 Certification Inc., a Montreal based company, has developed an innovative hands-on welding simulator solution to help build the welding workforce in the most simple way. The solution lies in virtual reality technology, which has been fully tested since the early 90's. President and founder of 123 Certification Inc., Mr. Claude Choquet Ing. Msc. IWE. acts as a bridge between the welding and the programming world. Working in these fields for more than 20 years. he has filed 12 patents world-wide for a gesture control platform with leading edge hardware related to simulation. In the summer of 2006. Mr Choquet was proud to be invited to the annual IIW International Weld ing Congress in Quebec City to launch the ARC+ welding simulator. A 100% virtual reality system and web based training center was developed to simulate multi process. multi-materiaL multi-position and multi pass welding. The simulator is intended to train welding students and apprentices in schools or industries. The welding simulator is composed of a real welding e[eetrode holder (SMAW-GTAW) and gun (GMAW-FCAW). a head mounted display (HMD), a 6 degrees of freedom tracking system for interaction between the user's hands and head. as well as external audio speakers. Both guns and HMD are interacting online and simultaneously. The welding simulation is based on the law of physics and empirical results from detailed analysis of a series of welding tests based on industrial applications tested over the last 20 years. The simulation runs in real-time, using a local logic network to determine the quality and shape of the created weld. These results are based on the orientation distance. and speed of the welding torch and depth of penetration. The welding process and resulting weld bc.1d are displayed in a virtual environment with screenplay interactive training modules. For review. weld quality and recorded process values can be displayed and diagnosed after welding. To help in the le.tming process, a

  11. Microstructures and Plane Energy Spectra of X80 Pipeline Steel Welded Joints by Submerged Arc Automatic Welding

    Institute of Scientific and Technical Information of China (English)

    KONG Dejun; YE Cundong; GUO Wei; WU Yongzhong; LONG Dan

    2014-01-01

    X80 pipeline steel was welded with submerged arc automatic welding, the microstructures, cavity sizes, fusion depths and plane scanning of chemical elements in the welded zone, fusion zone, heat affected zone and base steel were observed with OM (optical microscope) and SEM (scanning electron microscope), respectively. The experimental results show that there is main acicular ferrite in the base steel and welded zone, the microscopic structure of fusion zone is a blocked bainite, and the heat affected zone is composed of multilateral ferrite and pearlite. M-A unit of the welded zone is the main factor to strengthen the welded zone, composed of acicular ferrites. The percentage of cavities in the welded joint is less than that in the base steel, which is beneficial to increasing its mechanical performance and corrosion resistance. The fusion depth in the fusion zone and welded zone is 101.13μm and 115.85μm, respectively, and the distribution of chemical elements in the welded zone is uniform, no enrichment phenomena.

  12. A computer-based control system for keyhole plasma arc welding

    Institute of Scientific and Technical Information of China (English)

    Jia Chuanbao; Wu Chuansong; Zhang Yuming

    2007-01-01

    A new kind of control system for keyhole plasma arc welding (K-PAW) was developed based on the computer and the Graphics Language-LabVIEW. It can set and output the required current waveforms with desired decreasing slopes so that the corresponding "opening and closing" of keyhole can occur periodically. With this control strategy of welding current waveforms, the workpiece is fully penetrated while no burn-through occurs. Keyhole plasma arc welding experiments were conducted to verify the stability and reliability of the developed system.

  13. Effect Of Dynamic Characteristics of Power Supplies on Aerosol Composition While Welding With Coated Electrodes

    Science.gov (United States)

    Il'yaschenko, D. P.; Chinakhov, D. A.; Sadikov, I. D.

    2016-08-01

    In the context of a significant increase in production output and use of welding technologies in the manufacturing of engineering products the problem of hygienic characteristics of working conditions in arc fusion welding is becoming increasingly important. The work represents how the dynamic characteristics of a power supply affect the transfer of alloying elements from a coated electrode into a base metal, a slag phase and a solid component of welding fumes. Short-circuit current limiting in inverters reduces overheating of electrode metal drops by 15%; welding fumes quantitative component - to 38%; manganese - to 30%; thermal radiation intensity - by 37%.

  14. 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.

  15. Ballistic-Failure Mechanisms in Gas Metal Arc Welds of MIL A46100 Armor-Grade Steel: A Computational Investigation

    Science.gov (United States)

    2014-06-12

    P.O. Box 12211 Research Triangle Park, NC 27709-2211 Gas Metal Arc Welding (GMAW) Process Modeling; Ballistic Limit; Welded All-metal Armor REPORT...THE ABOVE ADDRESS. Clemson University 300 Brackett Hall Box 345702 Clemson, SC 29634 -5702 ABSTRACT Ballistic-Failure Mechanisms in Gas Metal Arc ...SECURITY CLASSIFICATION OF: In our recent work, a multi-physics computational model for the conventional Gas Metal Arc Welding (GMAW) joining process was

  16. 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.

  17. 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

    2016-01-01

    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.

  18. 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.

  19. Stability evaluation of short-circuiting gas metal arc welding based on ensemble empirical mode decomposition

    Science.gov (United States)

    Huang, Yong; Wang, Kehong; Zhou, Zhilan; Zhou, Xiaoxiao; Fang, Jimi

    2017-03-01

    The arc of gas metal arc welding (GMAW) contains abundant information about its stability and droplet transition, which can be effectively characterized by extracting the arc electrical signals. In this study, ensemble empirical mode decomposition (EEMD) was used to evaluate the stability of electrical current signals. The welding electrical signals were first decomposed by EEMD, and then transformed to a Hilbert–Huang spectrum and a marginal spectrum. The marginal spectrum is an approximate distribution of amplitude with frequency of signals, and can be described by a marginal index. Analysis of various welding process parameters showed that the marginal index of current signals increased when the welding process was more stable, and vice versa. Thus EEMD combined with the marginal index can effectively uncover the stability and droplet transition of GMAW.

  20. 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

    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 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 source....... It is highly desirable to extract groove features closer to the arc and thus facilitate for a nearly-closed-loop control situation. On the other hand, for performing seam tracking and nearly-closed-loop control it is not necessary to obtain very detailed information about the molten pool area as long as some...

  1. Research on the controller of an arc welding process based on a PID neural network

    Institute of Scientific and Technical Information of China (English)

    Kuanfang HE; Shisheng HUANG

    2008-01-01

    A controller based on a PID neural network(PIDNN)is proposed for an arc welding power source whose output characteristic in responding to a given value is quickly and intelligently controlled in the welding process.The new method syncretizes the PID control strategy and neural network to control the welding process intelligently,so it has the merit of PID control rules and the trait of better information disposal ability of the neural network.The results of simulation show that the controller has the properties of quick response,low overshoot quick convergence and good stable accuracy,which meet the requirements for control of the welding process.

  2. 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.

  3. Numerical simulation and experimental validation of arc welding of DMR-249A steel

    Directory of Open Access Journals (Sweden)

    Rishi Pamnani

    2016-08-01

    Full Text Available The thermo-mechanical attributes of DMR-249A steel weld joints manufactured by shielded metal arc welding (SMAW and activated gas tungsten arc welding (A-GTAW processes were studied using Finite Element Model (FEM simulation. The thermal gradients and residual stresses were analyzed with SYSWELD software using double ellipsoidal heat source distribution model. The numerically estimated temperature distribution was validated with online temperature measurements using thermocouples. The predicted residual stresses profile across the weld joints was compared with the values experimentally measured using non-destructive techniques. The measured and predicted thermal cycles and residual stress profile was observed to be comparable. The residual stress developed in double sided A-GTAW joint were marginally higher in comparison to five pass SMAW joint due to phase transformation associated with high heat input per weld pass for A-GTAW process. The present investigations suggest the applicability of numerical modeling as an effective approach for predicting the thermo-mechanical properties influenced by welding techniques for DMR-249A steel weld joints. The tensile, impact and micro-hardness tests were carried to compare the welds. Considering benefits of high productivity and savings of labor and cost associated with A-GTAW compared to SMAW process, the minor variation in residual stress build up of A-GTAW joint can be neglected to develop A-GTAW as qualified alternative welding technique for DMR-249A steel.

  4. Identification of GMAW dynamic process of arc welding robot based on radiation temperature measurement%基于辐射测温的弧焊机器人GMAW动态过程辨识

    Institute of Scientific and Technical Information of China (English)

    岳建锋; 李亮玉

    2007-01-01

    研究弧焊机器人GMAW(Gas Metal Arc Welding,熔化极气体弧焊)动态过程,采用比色测温仪对温度场特定点温度进行采集,采用面积法对送丝速度和测温点温度之间的模型进行了辨识.仿真结果表明,该模型准确地反映了输入输出的关系,仿真数据与实验数据的均方差仅为3%.

  5. Study on the measure to improve the arc stabilization in smaller current welding for the variable polarity GTAW power source

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The variable polarity power source which incorporates a constant current power and a secondary inverter does not need special apparatus for stabilizing arc. The pulse for stabilizing arc is created by the circuit structure itself. The paper analyzes the principle of acquiring the pulse, provides the better method to improve the arc stabilization under smaller welding current. Test shows the arc is highly stable , and the process has no high-frequency electromagnetic interference, which is suitable for automatic welding case.

  6. On-line quality monitoring in short-circuit gas metal arc welding

    Energy Technology Data Exchange (ETDEWEB)

    Adolfsson, S. [Univ. of Karlskrono/Ronneby (Sweden). Dept. of Signal Processing]|[Lund Univ. (Sweden). Dept. of Production and Materials Engineering; Bahrami, A. [Technology Center of Kronoberg, Vaexjoe (Sweden)]|[Lund Univ. (Sweden); Bolmsjoe, G. [Lund Univ. (Sweden); Claesson, I. [Univ. of Karlskrono/Ronneby (Sweden)

    1999-02-01

    This paper addresses the problems involved in the automatic monitoring of the weld quality produced by robotized short-arc welding. A simple statistical change detection algorithm for the weld quality, the repeated Sequential Probability Ratio Test (SPRT), was used. The algorithm may similarly be viewed as a cumulative sum (CUSUM) type test, and is well-suited to detecting sudden minor changes in the monitored test statistic. The test statistic is based on the variance of the weld voltage, wherein it will be shown that the variance decreases when the welding process is not operating under optimal conditions. The performance of the algorithm is assessed through the use of experimental data. The results obtained from the algorithm show that it is possible to detect changes in weld quality automatically and on-line.

  7. MODEL PEMBELAJARAN PRAKTIK PENGELASAN SHIELED METAL ARC WELDING(SMAW POSISI 1G JURUSAN TEKNIK PENGELASAN

    Directory of Open Access Journals (Sweden)

    Masri Bin Ardin

    2016-08-01

    Full Text Available Penelitian ini bertujuan untuk: (1 mendeskripsikan model pembelajaran praktik yang berlangsung atau disebut model pembelajaran regular praktek pengelasan SMAW posisi 1G di SMK Negeri 2 Pengasih; (2 mengetahui efektifitas dan mendeskripsikan bahan yang digunakan dalam praktek pengelasan SMAW posisi 1G, misalnya: besi plat, mata gerinda, elektroda, dan waktu yang digunakan selama praktek pengelasan SMAW posisi 1G. Penelitian ini merupakan penelitian deskriptif dengan teknik pengumpulan data menggunakan wawancara, dokumentasi, angket dan penilaian skill pengelasan. Asessment skill pengelasan mengacu pada Acean Skill Welding Competition. Hasil penelitian yaitu: (1 model pembelajaran praktek pengelasan SMAW posisi 1G terdiri dari 4 pertemuan teori dan 13 pertemuan praktik; (2 model pembelajaran praktik pengelasan di SMKN 2 Pengasih sudah efektif tetapi untuk rutinitas pengelasan belum efektif untuk membentuk skill pengelasan SMAW posisi 1G dengan sistem assesment Asean Skill Welding Competition. Fasilitas utama dalam praktek pengelasan SMAW posisi 1G adalah mesin las. Sementara itu SMKN 2 pengasih memiliki 6 buah mesin las dengan rasio 1 mesin las untuk 5 orang siswa. Bahan habis pakai untuk 30 orang siswa per semester yang menggunakan model pembelajaran praktek pengelasan adalah besi plat ± 100-150 kg, mata gerinda total ± 5-6 keping, elektroda ± 9-10 box dan total waktunya aktif 77 jam selama satu semester. Kata kunci: pembelajaran Praktik Pengelasan SMAW, Skill Siswa untuk Posisi 1G LEARNING MODEL OF SHIELD METAL ARC WELDING (SMAW PRACTICE OF 1G POSITION AT THE WELDING ENGINEERING DEPARTMENT Abstract This research aimed to: (1 describe the learning model of shield metal arc welding (SMAW practice of 1G position at the Welding Engineering Department of State Vocational High School (SMKN 2 Pengasih; (2 find the effectiveness and describe materials needed in the learning model of shield metal arc welding (SMAW practice of 1G position, for examples

  8. Causal Factors of Weld Porosity in Gas Tungsten Arc Welding of Powder-Metallurgy-Produced Titanium Alloys

    Science.gov (United States)

    Muth, T. R.; Yamamoto, Y.; Frederick, D. A.; Contescu, C. I.; Chen, W.; Lim, Y. C.; Peter, W. H.; Feng, Z.

    2013-05-01

    An investigation was undertaken using gas tungsten arc (GTA) welding on consolidated powder metallurgy (PM) titanium (Ti) plate to identify the causal factors behind observed porosity in fusion welding. Tramp element compounds of sodium and magnesium, residual from the metallothermic reduction of titanium chloride used to produce the titanium, were remnant in the starting powder and were identified as gas-forming species. PM-titanium made from revert scrap, where sodium and magnesium were absent, showed fusion weld porosity, although to a lesser degree. We show that porosity was attributable to hydrogen from adsorbed water on the surface of the powders prior to consolidation. The removal and minimization of both adsorbed water on the surface of titanium powder and the residues from the reduction process prior to consolidation of titanium powders are critical for achieving equivalent fusion welding success similar to that seen in wrought titanium produced via the Kroll process.

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

    Institute of Scientific and Technical Information of China (English)

    G. MADHUSUDHAN REDDY; K. SRINIVASA RAO

    2015-01-01

    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.

  10. 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.

  11. 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.

  12. 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.

  13. 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.)

  14. Process Parameter Optimization of the Pulsed Current Argon Tungsten Arc Welding of Titanium Alloy

    Institute of Scientific and Technical Information of China (English)

    M.Balasubramanian; V.Jayabalan; V.Balasubramanian

    2008-01-01

    The selection of process parameters for obtaining optimal tensile properties in the pulsed current gas tungsten arc welding is presented. The tensile properties include ultimate tensile strength, yield strength and notch tensile strength. All these characteristics are considered together in the selection of process parameters by modified taguchi method to analyse the effect of each welding process parameter on tensile properties. Experimental results are furnished to illustrate the approach.

  15. 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...

  16. The modeling of heat affected zone (HAZ in submerged arc welding (SAW surfacing steel element

    Directory of Open Access Journals (Sweden)

    J. Winczek

    2016-04-01

    Full Text Available In the work the bimodal heat source model in the description of the temperature field is presented. The electric arc was treated physically as one heat source, whose heat was divided: part of the heat is transferred by the direct impact of the electric arc, but another part of the heat is transferred to the weld by the melted material of the electrode. Computations of the temperature field during SAW surfacing of S355 steel element are carried out. The macrographic and metallographic analysis of the weld confirmed the depth and shapes of the fusion line and HAZ defined by the numerical simulation.

  17. Study on motion simulation of arc welding robot based on UG

    Institute of Scientific and Technical Information of China (English)

    Feng Shengqiang; Hu Shengsun; Du Naicheng; Shen Junqi

    2008-01-01

    The motion simulation of arc welding robot is the basis of the system of robot off-line programming, and it has been one of the important research directions. The UGNX4.0 is adopted to establish 3D simulating model of MOTOMAN-HP6 arc welding robot. The kinematic model under link-pole coordinate system is established by the second development function offered by UG/OPEN API and the method of programming using VC+ +6.0. The methods of founding model and operational procedures are introduced, which provides a good basis for off-line programming technique under Unigraphics condition.

  18. 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.

  19. Sensoring fusion data from the optic and acoustic emissions of electric arcs in the GMAW-S process for welding quality assessment.

    Science.gov (United States)

    Alfaro, Sadek Crisóstomo Absi; Cayo, Eber Huanca

    2012-01-01

    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.

  20. 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.

  1. The risk of cataract in relation to metal arc welding

    DEFF Research Database (Denmark)

    Slagor, Rebekka Michaelsen; La Cour, Morten; Bonde, Jens Peter

    2016-01-01

    Objectives: There are indications that solar ultraviolet radiation (UVR) increases the risk of cataract, but there is only circumstantial evidence that metal welding, an important occupational source of UVR exposure, is a risk factor. The objective of this study is to unravel if metal welding...

  2. 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.

  3. ELECTRIC ARC WELDING DEPOSITION OF METALLIC SURFACES BY VIBRATING ELECTRODE IN PROTECTIVE GAS MEDIUM

    Directory of Open Access Journals (Sweden)

    N. Spiridonov

    2013-01-01

    Full Text Available The paper presents methods for obtaining qualitative metallic surfaces by electric arc welding deposition while using consumable electrode in a protective gas medium and executing regularized drop transfer of electrode metal. The drop transfer efficiency of electrode metal and productivity of welding deposition are significantly increased due to excitation of lateral vibrations in the consumable electrode with preset amplitude. The paper describes a method and a device for welding deposition of metallic surfaces by vibrating  electrode where vibrations are excited by ultrasound.

  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. Weld pool temperatures of steel S235 while applying a controlled short-circuit gas metal arc welding process and various shielding gases

    Science.gov (United States)

    Kozakov, R.; Schöpp, H.; Gött, G.; Sperl, A.; Wilhelm, G.; Uhrlandt, D.

    2013-11-01

    The temperature determination of liquid metals is difficult and depends strongly on the emissivity. However, the surface temperature distribution of the weld pool is an important characteristic of an arc weld process. As an example, short-arc welding of steel with a cold metal transfer (CMT) process is considered. With optical emission spectroscopy in the spectral region between 660 and 840 nm and absolute calibrated high-speed camera images the relation between temperature and emissivity of the weld pool is determined. This method is used to obtain two-dimensional temperature profiles in the pictures. Results are presented for welding materials (wire G3Si1 on base material S235) using different welding CMT processes with CO2 (100%), Corgon 18 (18% CO2 + 82% Ar), VarigonH6 (93.5% Ar + 6.5% H2) and He (100%) as shielding gases. The different gases are used to study their influence on the weld pool temperature.

  6. 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.

  7. 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.

  8. Specifics of Pulsed Arc Welding Power Supply Performance Based On A Transistor Switch

    Science.gov (United States)

    Krampit, N. Yu; Kust, T. S.; Krampit, M. A.

    2016-08-01

    Specifics of designing a pulsed arc welding power supply device are presented in the paper. Electronic components for managing large current was analyzed. Strengths and shortcomings of power supply circuits based on thyristor, bipolar transistor and MOSFET are outlined. As a base unit for pulsed arc welding was chosen MOSFET transistor, which is easy to manage. Measures to protect a transistor are given. As for the transistor control device is a microcontroller Arduino which has a low cost and adequate performance of the work. Bead transfer principle is to change the voltage on the arc in the formation of beads on the wire end. Microcontroller controls transistor when the arc voltage reaches the threshold voltage. Thus there is a separation and transfer of beads without splashing. Control strategies tested on a real device and presented. The error in the operation of the device is less than 25 us, it can be used controlling drop transfer at high frequencies (up to 1300 Hz).

  9. 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

  10. Microstructure and Mechanical Properties of Narrow Gap Laser-Arc Hybrid Welded 40 mm Thick Mild Steel

    Directory of Open Access Journals (Sweden)

    Chen Zhang

    2017-01-01

    Full Text Available Both laser-arc hybrid welding and narrow gap welding have potential for the fabrication of thick sections, but their combination has been seldom studied. In this research, 40 mm thick mild steel was welded by narrow gap laser-arc hybrid welding. A weld with smooth layer transition, free of visible defects, was obtained by nine passes at a 6 mm width narrow gap. The lower part of the weld has the lowest mechanical properties because of the lowest amount of acicular ferrite, but its ultimate tensile strength and impact absorbing energy is still 49% and 60% higher than those of base metal, respectively. The microhardness deviation of all filler layers along weld thickness direction is no more than 15 HV0.2, indicating that no temper softening appeared during multiple heat cycles. The results provide an alternative technique for improving the efficiency and quality of welding thick sections.

  11. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Babu, N. Kishore, E-mail: nkishorebabu@gmail.com [Joining Technology Group, Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore); Talari, Mahesh Kumar [Faculty of Applied Sciences, Universiti Teknologi MARA, 40450 Shah Alam (Malaysia); Pan, D.; Sun, Z.; Wei, J. [Joining Technology Group, Singapore Institute of Manufacturing Technology, 71 Nanyang Drive, Singapore 638075 (Singapore); Sivaprasad, K. [Advanced Materials Processing Laboratory, Department of Metallurgical and Materials Engineering, National Institute of Technology, Tiruchirapalli 620015, Tamil Nadu (India)

    2012-12-14

    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 Al{sub 3}Sc particles, which act as heterogeneous nucleation of {alpha}-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 Al{sub 3}Sc precipitates at elevated temperatures were suggested to be responsible for the improved high temperature yield strength of welds made from Sc modified fillers. -- Highlights: Black-Right-Pointing-Pointer Primary Al{sub 3}Sc particles resulted in grain refinement by heterogeneous nucleation. Black-Right-Pointing-Pointer Weld metal strength and hardness improved due to grain refinement caused by Sc. Black-Right-Pointing-Pointer Weld metal responded to post-weld aging treatment due to dilution from base metal. Black-Right-Pointing-Pointer Sc addition improved the high temperature mechanical properties of welds.

  13. 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…

  14. 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

  15. Autogeneous Laser and Hybrid Laser Arc Welding of T-joint Low Alloy Steel with Fiber Laser Systems

    Science.gov (United States)

    Unt, A.; Lappalainen, E.; Salminen, A.

    This paper is focused on the welding of low alloy steels S355 and AH36 in thicknesses 6, 8 and 10 mm in T-joint configuration using either autogeneous laser welding or laser-arc hybrid welding (HLAW) with high power fiber lasers. The aim was to obtain understanding of the factors influencing the size of the fillet and weld geometry through methodologically studying effects of laser power, welding speed, beam alignment relative to surface, air gap, focal point position and order of processes (in case of HLAW) and to get a B quality class welds in all thicknesses after parameter optimization.

  16. Micro Structural Comparison of Friction Stir Weldment and Shielded Metal Arc Welding in API-X65 Pipe Line

    Directory of Open Access Journals (Sweden)

    Amin Shahinfar

    2015-04-01

    Full Text Available The study was conducted to investigate the microstructure and microhardness properties of the friction stir welded zones and shielded metal arc welded. Microstructural analysis of the weld was carried out using optical microscopy. Under FSW process base metal microstructure fully changed. Different heat inputs were obtained using a fix travel (welding speed in combination with several spindle speeds. Heat input during welding process had a significant influence on the microstructure and mechanical proprieties in the various weld regions.it can be concluded that with decrease in heat input the bainitic structure in the hard zone becomes finer and so hard zone hardness increase.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    1997-04-01

    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.

  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. Design of a robust fuzzy controller for the arc stability of CO(2) welding process using the Taguchi method.

    Science.gov (United States)

    Kim, Dongcheol; Rhee, Sehun

    2002-01-01

    CO(2) welding is a complex process. Weld quality is dependent on arc stability and minimizing the effects of disturbances or changes in the operating condition commonly occurring during the welding process. In order to minimize these effects, a controller can be used. In this study, a fuzzy controller was used in order to stabilize the arc during CO(2) welding. The input variable of the controller was the Mita index. This index estimates quantitatively the arc stability that is influenced by many welding process parameters. Because the welding process is complex, a mathematical model of the Mita index was difficult to derive. Therefore, the parameter settings of the fuzzy controller were determined by performing actual control experiments without using a mathematical model of the controlled process. The solution, the Taguchi method was used to determine the optimal control parameter settings of the fuzzy controller to make the control performance robust and insensitive to the changes in the operating conditions.

  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. Synthetically quantitative evaluation function of characteristic parameters on CO2 arc welding process

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The statistical probability and their variation regularity of the measurable characteristic parameters in the CO2 arc welding droplet short-circuiting transfer process have been studied. The statistical analysis shows that the sensitivity of each characteristic parameter with regard to the variation of the short-circuiting transfer process is different. The sensitivity of 4 kinds among these characteristic parameters is more intense than that of the short-circuiting transfer frequency. In order to take account of the synthetic influence of these characteristic parameters, by means of the characteristic parameters synthetic value, a quantitative evaluation function is built up to describe and evaluate the short-circuiting transfer process of CO2 arc welding in real time. The testing shows that the evaluation function can give a suitable synthetic valuation for the short-circuiting transfer process with a variety of welding variables.

  2. Influence of longitudinal magnetic field on metal transfer in MIG arc welding

    Institute of Scientific and Technical Information of China (English)

    Chang Yunlong; Che Xiaoping; He Youyou; Hu Guangxu

    2008-01-01

    Metal transfer is an important phenomenon in metal inert gas (MIG) arc welding with longitudinal alternating magnetic field. It is of great significance to observe the metal transfer modes under different excitatory currents and frequencies. However, it is very difficult to view the metal transfer process directly during welding, due to the strong interference from the arc light. To obtain the relationship between the metal transfer modes and the different magnetic fields, a high-speed video camera was used to acquire the images of globules. Different metal transfer modes under the conditions of different magnetic fields and welding parameters were studied. The experiment shows clear images of droplet transfer as well as influence of longitudinal magnetic field on both metal transfer and globule shape.

  3. Liquation Cracking in Arc and Friction-Stir Welding of Mg-Zn Alloys

    Science.gov (United States)

    Wagner, Dustin C.; Chai, Xiao; Tang, Xin; Kou, Sindo

    2015-01-01

    As compared to Al alloys, which are known to be susceptible to liquation ( i.e., liquid formation) and liquation-induced cracking, most Mg alloys have a lower eutectic temperature and thus are likely to be even more susceptible. The present study was conducted to study liquation and liquation cracking in Mg alloys during arc welding and friction-stir welding (FSW). Binary Mg-Zn alloys were selected as a model material in view of their very low eutectic temperature of 613 K (340 °C). Mg-Zn alloys with 2, 4, and 6 wt pct of Zn were cast and welded in the as-cast condition by both gas-tungsten arc welding (GTAW) and FSW. A simple test for liquation cracking was developed, which avoided interference by solidification cracking in the nearby fusion zone. Liquation and liquation cracking in GTAW were found to be in the decreasing order of Mg-6Zn, Mg-4Zn, and Mg-2Zn. Liquation cracking occurred in FSW of Mg-6Zn but not Mg-4Zn or Mg-2Zn. Instead of a continuous ribbon-like flash connected to the weld edge, small chips, and powder covered the weld surface of Mg-6Zn. The results from GTAW and FSW were discussed in light of the binary Mg-Zn phase diagram and the curves of temperature vs fraction solid during solidification.

  4. Initial Testing for the Recommendation of Improved Gas Metal Arc Welding Procedures for HY-80 Steel Plate Butt Joints at Norfolk Naval Shipyard

    Science.gov (United States)

    2015-12-01

    FOR THE RECOMMENDATION OF IMPROVED GAS METAL ARC WELDING PROCEDURES FOR HY-80 STEEL PLATE BUTT JOINTS AT NORFOLK NAVAL SHIPYARD by Veronika J...FOR THE RECOMMENDATION OF IMPROVED GAS METAL ARC WELDING PROCEDURES FOR HY-80 STEEL PLATE BUTT JOINTS AT NORFOLK NAVAL SHIPYARD 5. FUNDING NUMBERS 6...gas metal arc welding, submarine, hull cut, butt joint, weld, shielding gas, HY-80 steel , plate 15. NUMBER OF PAGES 53 16. PRICE CODE 17

  5. Study for the electric arc of alternative current at the single phase welding machine using the Matlab/Simulink environment

    Science.gov (United States)

    Baciu, I.; Ghiormez, L.; Vasar, C.

    2017-01-01

    In this paper is presented a mathematical model of the electric arc for an alternative current welding machine of low power. The electric arc model is based on dividing the voltage-current characteristic of the electric arc in many functioning zones. For the model of the entire welding machine are used real parameters as the ones of the proper welding machine. The voltage and current harmonics spectrum that is obtained during the welding process is presented. Also, the waveforms for the current and voltage of the electric arc plotted against time and the voltage-current characteristic of the electric arc are illustrated. The electric arc is considered as being supplied by alternative voltage from the electrical power network using a single phase transformer which has the output voltage of 80 volts. The model of the welding machine is developed in Simulink and the variations of some parameters of the electric arc are obtained by modifying of them in a Matlab function. Also, in this paper is presented the total harmonic distortion for the voltage and current of the electric arc obtained during simulation of the welding machine.

  6. Post-weld Tempered Microstructure and Mechanical Properties of Hybrid Laser-Arc Welded Cast Martensitic Stainless Steel CA6NM

    Science.gov (United States)

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

    2016-12-01

    Manufacturing of hydroelectric turbine components involves the assembly of thick-walled stainless steels using conventional multi-pass arc welding processes. By contrast, hybrid laser-arc welding may be an attractive process for assembly of such materials to realize deeper penetration depths, higher production rates, narrower fusion, and heat-affected zones, and lower distortion. In the present work, single-pass hybrid laser-arc welding of 10-mm thick CA6NM, a low carbon martensitic stainless steel, was carried out in the butt joint configuration using a continuous wave fiber laser at its maximum power of 5.2 kW over welding speeds ranging from 0.75 to 1.2 m/minute. The microstructures across the weldment were characterized after post-weld tempering at 873 K (600 °C) for 1 hour. From microscopic examinations, the fusion zone was observed to mainly consist of tempered lath martensite and some residual delta-ferrite. The mechanical properties were evaluated in the post-weld tempered condition and correlated to the microstructures and defects. The ultimate tensile strength and Charpy impact energy values of the fully penetrated welds in the tempered condition were acceptable according to ASTM, ASME, and industrial specifications, which bodes well for the introduction of hybrid laser-arc welding technology for the manufacturing of next generation hydroelectric turbine components.

  7. Nuclear Technology. Course 28: Welding Inspection. Module 28-3, Tungsten Inert Gas (TIG), Metal Inert Gas (MIG) and Submerged Arc Welding.

    Science.gov (United States)

    Espy, John

    This third in a series of ten modules for a course titled Welding Inspection presents the apparatus, process techniques, procedures, applications, associated defects, and inspection for the tungsten inert gas, metal inert gas, and submerged arc welding processes. The module follows a typical format that includes the following sections: (1)…

  8. A Study on Process Characteristics and Performance of Hot Wire Gas Tungsten Arc Welding Process for High Temperature Materials

    OpenAIRE

    Padmanaban MR,Anantha; Neelakandan, Baskar; Kandasamy,Devakumaran

    2016-01-01

    Hot wire gas tungsten arc welding (HW-GTAW) process is the one where the filler wire is pre-heated close to its melting point before it is fed in to the arc. The effect of HW-GTAW parameters such as welding current, hot wire current and the wire feed rate during welding of super ASS 304H stainless steel tubes were evaluated in terms of heat input, voltage-current (V-I) characteristics and weld bead characteristics such as bead weight and geometry. The results obtained indicate that for a cons...

  9. Effects of distance between arc and heat sink on stress and distortion in DC-LSND welding technology

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The characteristics of temperatures, stresses and strains fields have been studied numerically for a titanium alloy sheet welded with an improved gas tungsten arc welding method, in which a trailing spot heat sink is introduced to control the welding stress and distortion. The impinging jet model is employed to describe the intense heat transfer between the cooling media and the top surface of the workpiece. The influence of the distance between arc and heat sink is investigated. Results show that there is an ideal range of distance. Using the ideal distance, a low stress and no distortion welding structure can be derived.

  10. Initial testing for the recommendation of improved gas metal arc welding procedures for HY-80 steel plate butt joints at Norfolk Naval Shipyard

    OpenAIRE

    Rice, Veronika J.

    2015-01-01

    Approved for public release; distribution is unlimited Hull cut welding proficiency is an essential skill maintained by personnel at naval shipyards. This thesis explores arc weld theory to develop ideal submarine hull butt joint designs and recommends preliminary testing to be used to develop improved butt joint welding procedures at Norfolk Naval Shipyard. Pulsed gas metal arc welding (GMAW-P) is the ideal process for shipboard hull welding applications, theoretically. Butt joint samples...

  11. Enhancing Stud Arc Welding Technique Vai Utilizing FuzzyLogic Approach (FLA

    Directory of Open Access Journals (Sweden)

    Nabeel K. Abid AL-Sahib

    2013-01-01

    Full Text Available A fuzzy logic approach (FLA application in the process of stud arc welding environment was implemented under the condition of fuzziness input data. This paper is composed of the background of FLA, related research work review and points for developing in stud welding manufacturing. Then, it investigates thecase of developingstud arc welding process on the controversial certaintyof available equipment and human skills.Five parameters (welding time, sheet thickness, type of coating, welding current and stud shape were studied.A pair of parameter was selected asiteration whichis welding current and welding time and used for verification corresponding with tensile strength as output results and this willconsider it as schema for other cases.The testing result in the case of crisp (exact value verifyingied the uncertainty value of some criteria selected which open the concept to make the decision making process for some advance cases without implementation. This paper applied the proposed methodology using Matlab program, the graphic user interface (GUI fuzzy tool box for the case study of screw DABOTEKSTUD welding machine, for 6 mm diameter stud. The sheet materials are (K14358 and K52355 according to (USN standards, and the stud materials are (54NiCrMoS6 and 4OCrMnMoS8-6 according to (DIN standards.This given information is very inevitable for the conventional crisp determination of the tensile stress for the particular specimens experimented and also for verifying the tensile test value estimate in the case of changing to a fuzzy value for two of the input variables.

  12. Experimental and numerical investigations of hybrid laser arc welding of aluminum alloys in the thick T-joint configuration

    Science.gov (United States)

    Mazar Atabaki, M.; Nikodinovski, M.; Chenier, P.; Ma, J.; Liu, W.; Kovacevic, R.

    2014-07-01

    In the present investigation, a numerical finite element model was developed to simulate the hybrid laser arc welding of different aluminum alloys, namely 5××× to 6××× series. The numerical simulation has been considered two double-ellipsoidal heat sources for the gas metal arc welding and laser welding. The offset distance of the metal arc welding and laser showed a significant effect on the molten pool geometry, the heat distribution and penetration depth during the welding process. It was confirmed that when the offset distance is within the critical distance the laser and arc share the molten pool and specific amount of penetration and dilution can be achieved. The models and experiments show that the off-distance between the two heat sources and shoulder width have considerable influence on the penetration depth and appearance of the weld beads. The experiments also indicate that the laser power, arc voltage and type of the filler metal can effectively determine the final properties of the bonds, specifically the bead appearance and microhardness of the joints. The experiments verified the numerical simulation as the thermocouples assist to comprehend the amount of heat distribution on the T-joint coupons. The role of the welding parameters on the mechanism of the hybrid laser welding of the aluminum alloys was also discussed.

  13. 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.

  14. Fuzzy neural networks for arc welding quality control

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Fuzzy Logic Control (FLC) is a promising control strategy in welding process control due to its ability for solving control problem with uncertainty as well as its independence on the analytical mathematics model. However, in basic FLC, the fuzzy rule relies heavily on the experts' (e.g. advanced welders') experience. In addition to this, the membership function for fuzzy set is non-adaptive, i.e. it remains unchanged as long as they are determined by experience or other means. For welding process, which is time-variable systems and strong disturbance exists in it, fixed membership function may not guarantee the required system performance, and attempts should be made to improve the system performance by adopting adaptive membership function. Therefore, the automatically determination of the fuzzy rule and in-process adaptation of membership function are required for the advanced welding process control. This paper discussed the possibility by using the combination between FLC and neural network (NN) to realize the above propose. The adaptation of membership function as well as the self-organizing of fuzzy rule are realized by the self-learning and competitiveness of the NN. Taking GTAW process welds bead width regulating system as the controlled plant, the proposed algorithm was testified for such a process. Computer simulations showed the improvement of the system characteristics.

  15. 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.

  16. Source profile derivation for an arc welding shop using time sequenced sampling and PIXE analysis

    Science.gov (United States)

    Formenti, P.; Van Den Heever, D. J.; Annegarn, H. J.

    1998-03-01

    Samples of particulate concentration inside a welding shop in Bloemfontein (South Africa) were collected for two weeks during August 1995 using a single stage time sequenced sampler (streaker sampler). Inorganic elemental concentrations (μg/m 3) for 12 metallic rods are melted through electric arc welding to join steel plates. The absence of proper ventilation in the building, due to the closing of doors and windows during winter conditions, results in accumulation of pollutants and in enhanced hazardous conditions for the workers. Analysis of temporal coincidences of elemental concentrations time series formed the basis for extracting the arc welding source profile. Major periodical and episodic contributors to the indoor pollution were qualitatively observed during the sampling period. Due to the hourly time resolution of the sampling, their different time dependence could be identified and isolated. The welding shop activities were found to be characterised by high metal concentrations ([Fe] up to 95 μg/m 3) and variations in the Cu-to-Fe and Mn-to-Fe ratios within 30% over a week period. Cr concentrations up to 7 μg/m 3 were detected over 8-h shift periods. A profile for soil dust in the welding shop air was extracted, and was found to be enriched in Cr, Mn and Fe. This identifies the existence of a secondary source of heavy metal particulate exposure, to which all the workers, not only welders during their shifts, are exposed.

  17. 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

  18. Computer simulation in the design of local exhaust hoods for shielded metal arc welding.

    Science.gov (United States)

    Tum Suden, K D; Flynn, M R; Goodman, R

    1990-03-01

    Computer simulations were used to examine competing exhaust hood configurations for shielded metal arc welding. The welder's breathing zone concentration appears to be an inverse linear function of the computer-predicted hood capture efficiency. Hood aspect ratio, hood flow, and the welder's position relative to the hood all have a significant effect on the breathing zone concentration. The height of the hood above the welding surface showed no significant effect in reducing breathing zone concentration. Further examination of breathing zone concentration as a function of capture efficiency is needed before reliable design methods can be developed using this parameter.

  19. 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.

  20. 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.

  1. Characterization of HAZ of API X70 Microalloyed Steel Welded by Cold-Wire Tandem Submerged Arc Welding

    Science.gov (United States)

    Mohammadijoo, Mohsen; Kenny, Stephen; Collins, Laurie; Henein, Hani; Ivey, Douglas G.

    2017-03-01

    High-strength low-carbon microalloyed steels may be adversely affected by the high-heat input and thermal cycle that they experience during tandem submerged arc welding. The heat-affected zone (HAZ), particularly the coarse-grained heat-affected zone (CGHAZ), i.e., the region adjacent to the fusion line, has been known to show lower fracture toughness compared with the rest of the steel. The deterioration in toughness of the CGHAZ is attributed to the formation of martensite-austenite (M-A) constituents, local brittle zones, and large prior austenite grains (PAG). In the present work, the influence of the addition of a cold wire at various wire feed rates in cold-wire tandem submerged arc welding, a recently developed welding process for pipeline manufacturing, on the microstructure and mechanical properties of the HAZ of a microalloyed steel has been studied. The cold wire moderates the heat input of welding by consuming the heat of the trail electrode. Macrostructural analysis showed a decrease in the CGHAZ size by addition of a cold wire. Microstructural evaluation, using both tint etching optical microscopy and scanning electron microscopy, indicated the formation of finer PAGs and less fraction of M-A constituents with refined morphology within the CGHAZ when the cold wire was fed at 25.4 cm/min. This resulted in an improvement in the HAZ impact fracture toughness. These improvements are attributed to lower actual heat introduced to the weldment and lower peak temperature in the CGHAZ by cold-wire addition. However, a faster feed rate of the cold wire at 76.2 cm/min adversely affected the toughness due to the formation of slender M-A constituents caused by the relatively faster cooling rate in the CGHAZ.

  2. Dissimilar Arc Welding of Advanced High-Strength Car-Body Steel Sheets

    Science.gov (United States)

    Russo Spena, P.; D'Aiuto, F.; Matteis, P.; Scavino, G.

    2014-11-01

    A widespread usage of new advanced TWIP steel grades for the fabrication of car-body parts is conditional on the employment of appropriate welding methods, especially if dissimilar welding must be performed with other automotive steel grades. Therefore, the microstructural features and the mechanical response of dissimilar butt weld seams of TWIP and 22MnB5 steel sheets after metal-active-gas arc welding are examined. The microstructural and mechanical characterization of the welded joints was carried out by optical metallography, microhardness and tensile testing, and fractographic examination. The heat-affected zone on the TWIP side was fully austenitic and the only detectable effect was grain coarsening, while on the 22MnB5 side it exhibited newly formed martensite and tempered martensite. The welded tensile specimens exhibited a much larger deformation on the TWIP steel side than on the 22MnB5. The fracture generally occurred at the interface between the fusion zone and the heat-affected zones, with the fractures surfaces being predominantly ductile. The ultimate tensile strength of the butt joints was about 25% lower than that of the TWIP steel.

  3. 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.

  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. Optimization of arc-start performance by wire-feeding control for GMA welding

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Jong Gu; Ryu, Gyeong Su; Rhee, Se Hun [Hanyang University, Seoul (Korea, Republic of); Kim, Dong Cheol; Kang, Mun Jin [Korea Institute of Industrial Technology, Incheon (Korea, Republic of); Park, Young Whan [Pukyong National University, Busan (Korea, Republic of)

    2013-02-15

    The wire feeding system for gas metal arc welding usually consists of a wire feeder and a torch. In many industries, the distance between the wire feeder and the torch is generally 3 m to 5 m. In a conventional wire feeder, a direct current (DC) motor is used for wire feeding. However, a significant problem with this system is the impossibility of feedback control because of inner or outer impedance. In this paper, a digital wire feeder was developed by using a DC encoder motor and a push-pull torch. An optimized wire-feeding system was also developed by experiment. The welding process was observed using a high-speed camera. The resulting wire-feeding system exhibits low spatter generation and arc stability.

  6. Numerical estimation of structure composition in laser-arc hybrid welded joints

    Directory of Open Access Journals (Sweden)

    W. Piekarska

    2010-10-01

    Full Text Available This work presents results of numerical estimation of the structure composition in laser-arc hybrid welded joints. Temperature field wasobtained by the solution of the heat transfer equation with activity of inner heat sources. Convective motion of liquid metal in the welding pool, latent heat of fusion and latent heat of phase transformation were taken into account in the algorithms for numerical analysis of the temperature field. The volumetric fractions of arising phases were determined on the basis of Johnson - Mehl - Avrami (JMA model for diffusive transformations and Koistinen - Marburger (KM model for martensitic transformation. On the basis of calculated temperature distribution the structure composition in welded joint was numerically estimated, taking into account CHT and CCT diagrams for S355 steel.

  7. Arc-Welding Spectroscopic Monitoring based on Feature Selection and Neural Networks

    Directory of Open Access Journals (Sweden)

    Jose M. Lopez- Higuera

    2008-10-01

    Full Text Available A new spectral processing technique designed for application in the on-line detection and classification of arc-welding defects is presented in this paper. A noninvasive fiber sensor embedded within a TIG torch collects the plasma radiation originated during the welding process. The spectral information is then processed in two consecutive stages. A compression algorithm is first applied to the data, allowing real-time analysis. The selected spectral bands are then used to feed a classification algorithm, which will be demonstrated to provide an efficient weld defect detection and classification. The results obtained with the proposed technique are compared to a similar processing scheme presented in previous works, giving rise to an improvement in the performance of the monitoring system.

  8. 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.

  9. Calculation of t8/5 by response surface methodology for electric arc welding applications

    Directory of Open Access Journals (Sweden)

    Meseguer-Valdenebro José Luis

    2014-01-01

    Full Text Available One of the greatest difficulties traditionally found in stainless steel constructions has been the execution of welding parts in them. At the present time, the available technology allows us to use arc welding processes for that application without any disadvantage. Response surface methodology is used to optimise a process in which the variables that take part in it are not related to each other by a mathematical law. Therefore, an empiric model must be formulated. With this methodology the optimisation of one selected variable may be done. In this work, the cooling time that takes place from 800 to 500ºC, t8/5, after TIG welding operation, is modelled by the response surface method. The arc power, the welding velocity and the thermal efficiency factor are considered as the variables that have influence on the t8/5 value. Different cooling times,t8/5, for different combinations of values for the variables are previously determined by a numerical method. The input values for the variables have been experimentally established. The results indicate that response surface methodology may be considered as a valid technique for these purposes.

  10. Microstructure evolution of Al/Mg butt joints welded by gas tungsten arc with Zn filler metal

    Energy Technology Data Exchange (ETDEWEB)

    Liu Fei; Zhang Zhaodong; Liu Liming, E-mail: liulm@dlut.edu.cn

    2012-07-15

    Based on the idea of alloying welding seam, Gas tungsten arc welding method with pure Zn filler metal was chosen to join Mg alloy and Al alloy. The microstructures, phases, element distribution and fracture morphology of welding seams were examined. The results indicate that there was a transitional zone in the width of 80-100 {mu}m between the Mg alloy substrate and fusion zone. The fusion zone was mainly composed of MgZn{sub 2}, Zn-based solid solution and Al-based solid solution. The welding seam presented distinct morphology in different location owning to the quite high cooling rate of the molten pool. The addition of Zn metal could prevent the formation of Mg-Al intermetallics and form the alloyed welding seam during welding. Therefore, the tensile strengths of joints have been significantly improved compared with those of gas tungsten arc welded joints without Zn metal added. Highlights: Black-Right-Pointing-Pointer Mg alloy AZ31B and Al alloy 6061 are welded successfully. Black-Right-Pointing-Pointer Zinc wire is employed as a filler metal to form the alloyed welding seam. Black-Right-Pointing-Pointer An alloyed welding seam is benefit for improving of the joint tensile strength.

  11. Gas Metal Arc Welding Process Modeling and Prediction of Weld Microstructure in MIL A46100 Armor-Grade Martensitic Steel

    Science.gov (United States)

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

    2013-06-01

    A conventional gas metal arc welding (GMAW) butt-joining process has been modeled using a two-way fully coupled, transient, thermal-mechanical finite-element procedure. To achieve two-way thermal-mechanical coupling, the work of plastic deformation resulting from potentially high thermal stresses is allowed to be dissipated in the form of heat, and the mechanical material model of the workpiece and the weld is made temperature dependent. Heat losses from the deposited filler-metal are accounted for by considering conduction to the adjoining workpieces as well as natural convection and radiation to the surroundings. The newly constructed GMAW process model is then applied, in conjunction with the basic material physical-metallurgy, to a prototypical high-hardness armor martensitic steel (MIL A46100). The main outcome of this procedure is the prediction of the spatial distribution of various crystalline phases within the weld and the heat-affected zone regions, as a function of the GMAW process parameters. The newly developed GMAW process model is validated by comparing its predictions with available open-literature experimental and computational data.

  12. 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.

  13. Dissimilar steel welding and overlay covering with nickel based alloys using SWAM (Shielded Metal Arc Welding) and GTAW (Gas Tungsten Arc Welding) processes in the nuclear industry

    Energy Technology Data Exchange (ETDEWEB)

    Arce Chilque, Angel Rafael [Centro Tecnico de Engenharia e Inovacao Empresarial Ltda., Belo Horizonte, MG (Brazil); Bracarense, Alexander Queiroz; Lima, Luciana Iglesias Lourenco [Federal University of Minas Gerais (UFMG), Belo Horizonte, MG (Brazil); Quinan, Marco Antonio Dutra; Schvartzman, Monica Maria de Abreu Mendonca [Nuclear Technology Development Centre (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Marconi, Guilherme [Federal Center of Technological Education (CEFET-MG), Belo Horizonte, MG (Brazil)

    2009-07-01

    This work presents the welding of dissimilar ferritic steel type A508 class 3 and austenitic stainless steel type AISI 316 L using Inconel{sup R} 600 (A182 and A82) and overlay covering with Inconel{sup R} 690 (A52) as filler metal. Dissimilar welds with these materials without defects and weldability problems such as hot, cold, reheat cracking and Ductility Dip Crack were obtained. Comparables mechanical properties to those of the base metal were found and signalized the efficiency of the welding procedure and thermal treatment selected and used. This study evidences the importance of meeting compromised properties between heat affected zone of the ferritic steel and the others regions presents in the dissimilar joint, to elaborate the dissimilar metal welding procedure specification and weld overlay. Metallographic studies with optical microscopy and Vickers microhardness were carried out to justified and support the results, showing the efficiency of the technique of elaboration of dissimilar metal welding procedure and overlay. The results are comparables and coherent with the results found by others. Some alternatives of welding procedures are proposed to attain the efficacy. Further studies are proposed like as metallographic studies of the fine microstructure, making use, for example, of scanning electron microscope (SEM adapted with an EDS) to explain looking to increase the resistance to primary water stress corrosion (PWSCC) in nuclear equipment. (author)

  14. 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.

  15. Real-time monitoring of abnormal conditions based on Fuzzy Kohonen clustering network in gas metal arc welding

    Institute of Scientific and Technical Information of China (English)

    GAO Jinqiang; WU Chuansong; HU Jiakun

    2007-01-01

    A real-time monitoring system based on through-the-arc sensing is developed for detecting abnormal conditions in gas metal arc welding. The transient signals of welding voltage and current during the welding process are sampled and processed by statistical analysis methods. It is found that three statistical parameters (the standard deviation,variance, and kurtosis of welding current) show obvious variations during the step disturbance, which is intentionally introduced into the T-joint test pieces by cutting a gap in the vertical plane. A Fuzzy Kohonen clustering network (FKCN) is put forward to monitor the abnormal conditions in real-time. Ten robotic welding experiments are conducted to verify the real-time monitoring system. It is found that the correct identification rate is above 90%.

  16. Comparison of Three Control Methods in Penetration Control of Pulsed Gas Tungsten Arc Welding

    Institute of Scientific and Technical Information of China (English)

    陈文杰; 陈善本; 林涛

    2003-01-01

    An artificial neural network model for backside bead width was established and three control meth-ods PID, fuzzy and neuron were designed, simulated and tested. The test results of bead-on-plate weld ofGTAW indicate that the artificial neural network (ANN) modeling and learning control method have more advan-tages than the conventional method. They show that the ANN modeling and learning control method is an effectiveapproach to real time control of welding dynamics and ideal quality.

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

    OpenAIRE

    R.V. Krishnarao; G. Madhusudhan Reddy

    2015-01-01

    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...

  18. ELECTRIC WELDING EQUIPMENT AND AUTOMATION OF WELDING IN CONSTRUCTION,

    Science.gov (United States)

    WELDING , *ARC WELDING , AUTOMATION, CONSTRUCTION, INDUSTRIES, POWER EQUIPMENT, GENERATORS, POWER TRANSFORMERS, RESISTANCE WELDING , SPOT WELDING , MACHINES, AUTOMATIC, STRUCTURES, WIRING DIAGRAMS, USSR.

  19. Study on image acquisition in 3-D sensor system of arc welding pool surface shape using grating projection

    Science.gov (United States)

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

    2009-11-01

    Detecting 3-D information on welding pool surface shape is difficult due to the arc light interference, high temperature radiation and pool surface specular reflection. The characteristics of mirror like reflection on pool of liquid surface are studied. Besides the way to obtain clear information-rich image of the pool area is discussed under the strong arc light. Because of the strong arc light above the pool will affect the imaging of the relatively weaker laser stripes seriously, we need to choose a suitable shooting angle and shooting distance to achieve well image. According to all these factors, the optimal combination of the sensing structure parameters in theory is deduced. Based on this work, a vision detecting of arc welding pool surface topography system was putted up in our laboratory, also actual measurement was carried out to obtain more clear images of deformation laser stripes in welding pool. This will provide the three-dimensional reconstruction a strong support.

  20. 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.

  1. Numerical Modeling of Enhanced Nitrogen Dissolution During Gas Tungsten Arc Welding

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, T A

    2001-08-17

    Nitrogen concentrations far in excess of Sieverts' Law calculations and as high as 0.2 wt.% have been obtained in steel welds during arc welding. Such high concentrations of nitrogen in the weld metal can originate from a variety of sources, depending on the welding operation in question. One such mechanism involves the interaction between the surrounding atmosphere, which is about 80% nitrogen, and the plasma phase above the weld pool. Impingement of the surrounding atmosphere into the arc column, which is primarily composed of an inert shielding gas, can be due, in part, to insufficient shielding of the weld metal. In other cases, nitrogen can be purposefully added to the shielding gas to enhance the microstructural evolution of the weld metal. The mechanisms responsible for enhanced nitrogen concentrations are of significant interest. In both arc melting and welding operations, a plasma phase exists above the liquid metal. This plasma phase, which is composed of a number of different species not normally observed in gas-metal systems, significantly alters the nitrogen absorption reaction in liquid iron and steel. Monatomic nitrogen (N) is considered to be the species responsible for the observed enhancements in the nitrogen concentration. This role for monatomic nitrogen is based on its significantly higher solubility in iron with partial pressures many orders of magnitude less than that for diatomic nitrogen. It has also been proposed that the total amount of nitrogen present in the liquid metal is the balance of two independent processes. Monatomic nitrogen is absorbed through the interface between the arc and the liquid metal. Once a saturation level is reached at any location on the metal surface, nitrogen is then expelled from the surface of the liquid metal. This expulsion of nitrogen from the weld pool surface occurs via a desorption reaction, in which bubbles form at the surface and other heterogeneous nucleation sites in the liquid melt. These

  2. Hybrid laser-arc welding of galvanized high-strength steels in a gap-free lap-joint configuration

    Science.gov (United States)

    Yang, Shanglu

    In order to meet the industry demands for increased fuel efficiency and enhanced mechanical and structural performance of vehicles as well as provided excellent corrosion resistance, more and more galvanized advanced high-strength steels (AHSS) have been used to fabricate automobile parts such as panels, bumpers, and front rails. The automotive industry has shown tremendous interest in using laser welding to join galvanized dual phase steels because of lower heat input and higher welding speed. However, the laser welding process tends to become dramatically unstable in the presence of highly pressurized zinc vapor because of the low boiling point of zinc, around 906°C, compared to higher melting point of steel, over 1500°C. A large number of spatters are produced by expelling the liquid metal from the molten pool by the pressurized zinc vapor. Different weld defects such as blowholes and porosities appear in the welds. So far, limited information has been reported on welding of galvanized high strength dual-phase steels in a gap-free lap joint configuration. There is no open literature on the successful attainment of defect-free welds from the laser or hybrid welding of galvanized high-strength steels. To address the significant industry demand, in this study, different welding techniques and monitoring methods are used to study the features of the welding process of galvanized DP steels in a gap-free lap joint configuration. The current research covers: (i) a feasibility study on the welding of galvanized DP 980 steels in a lap joint configuration using gas tungsten arc welding (GTAW), laser welding, hybrid laser/arc welding with the common molten pool, laser welding with the assistance of GTAW preheating source and hybrid laser-variable polarity gas tungsten arc welding (Laser-VPGTAW) techniques (Chapter 2-4); (ii) a welding process monitoring of the welding techniques including the use of machine vision and acoustic emission technique (Chapter 5); (iii

  3. 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.

  4. Study of Radiographic Linear Indications and Subsequent Microstructural Features in Gas Tungsten Arc Welds of Inconel 718

    Science.gov (United States)

    Walley, J. L.; Nunes, A. C.; Clounch, J. L.; Russell, C. K.

    2007-01-01

    This study presents examples and considerations for differentiating linear radiographic indications produced by gas tungsten arc welds in a 0.05-in-thick sheet of Inconel 718. A series of welds with different structural features, including the enigma indications and other defect indications such as lack of fusion and penetration, were produced, radiographed, and examined metallographically. The enigma indications were produced by a large columnar grain running along the center of the weld nugget occurring when the weld speed was reduced sufficiently below nominal. Examples of respective indications, including the effect of changing the x-ray source location, are presented as an aid to differentiation. Enigma, nominal, and hot-weld specimens were tensile tested to demonstrate the harmlessness of the enigma indication. Statistical analysis showed that there is no difference between the strengths of these three weld conditions.

  5. Computational Modeling of Microstructural-Evolution in AISI 1005 Steel During Gas Metal Arc Butt Welding

    Science.gov (United States)

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

    2013-05-01

    A fully coupled (two-way), transient, thermal-mechanical finite-element procedure is developed to model conventional gas metal arc welding (GMAW) butt-joining process. Two-way thermal-mechanical coupling is achieved by making the mechanical material model of the workpiece and the weld temperature-dependent and by allowing the potential work of plastic deformation resulting from large thermal gradients to be dissipated in the form of heat. To account for the heat losses from the weld into the surroundings, heat transfer effects associated with natural convection and radiation to the environment and thermal-heat conduction to the adjacent workpiece material are considered. The procedure is next combined with the basic physical-metallurgy concepts and principles and applied to a prototypical (plain) low-carbon steel (AISI 1005) to predict the distribution of various crystalline phases within the as-welded material microstructure in different fusion zone and heat-affected zone locations, under given GMAW-process parameters. The results obtained are compared with available open-literature experimental data to provide validation/verification for the proposed GMAW modeling effort.

  6. 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.

  7. MECHANICAL PROPERTIES OF LONGITUDINAL SUBMERGED ARC WELDED STEEL PIPES USED FOR GAS PIPELINE OF OFFSHORE OIL

    Institute of Scientific and Technical Information of China (English)

    Z.Z. Yang; W. Tian; Q.R. Ma; Y.L. Li; J.K. Li; J.Z. Gao; H.B. Zhang; Y.H. Yang

    2008-01-01

    Since the development of offshore oil and gas, increased submarine oil and gas pipelines were installed. All the early steel pipes of submarine pipelines depended on importing because of the strict requirements of comprehensive properties, such as,anti-corrosion, resistance to pressure and so on. To research and develop domestic steel pipes used for the submarine pipeline, the Longitudinal-seam Submerged Arc Welded (LSAW) pipes were made of steel plates cut from leveled hot rolled coils by both the JCOE and UOE (the forming process in which the plate like the letter "J", "C", "O" or "U" shape, then expansion) forming processes. Furthermore, the mechanical properties of the pipe base metal and weld metal were tested, and the results were in accordance with the corresponding pipe specification API SPEC 5L or DNV-OS-F101, which showed that domestic LSAW pipes could be used for submarine oil and gas pipelines.

  8. A novel arc welding inverter with unit power factor based on DSP control

    Institute of Scientific and Technical Information of China (English)

    Chen Shujun; Zeng Hua; Du Li; Yin Shuyan; Chen Yonggang

    2006-01-01

    A novel inverter power source is developed characterized with constant output current and unit power factor input.Digital signal processor (DSP) is used to realize power factor correction and control of back-stage inverter bridge of the arc welding inverter. The fore-stage adopts double closed loop proportion and integration (PI) rectifier technique and the backstage adopts digital pulse width modulation (PWM) technique. Simulated waves can be obtained in Matlab/Simulink and validated by experiments. Experiments of the prototype showed that the total harmonic distortion (THD) can be controlled within 10% and the power factor is approximate to 1.

  9. Change of electrical conductivity of Ar welding arc under resonant absorption of laser radiation

    Science.gov (United States)

    Kozakov, R.; Emde, B.; Pipa, A. V.; Huse, M.; Uhrlandt, D.; Hermsdorf, J.; Wesling, V.

    2015-03-01

    Experimental investigations of the impact of resonant laser absorption by a tungsten inert gas welding arc in argon are presented. The intensity increase of the arc’s radiation between the laser entrance height and the anode are observed, as well as the variation of arc voltage due to the presence of the laser beam. High-speed camera recordings from different directions combined with absolutely calibrated spectroscopic measurements allow the reconstruction of the three-dimensional emission coefficient profiles without the assumption of axial symmetry. The obtained data are evaluated within the framework of local thermodynamic equilibrium. The local increase in the temperature and conductivity due to the influence of the laser is determined. Changes in the electrical conductivity obtained from the optical measurements coincide well with the measured voltage drop, and show significant redistribution of the current density profile near the anode in particular.

  10. 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.

  11. Application of arc welding robot on car frame%弧焊机器人在车架焊接上的应用

    Institute of Scientific and Technical Information of China (English)

    倪宝; 吕家友

    2013-01-01

    This paper introduces the FANUC welding robot system in the application of Chery car frame welding.The control system hardware block diagram,instruction,welding,welding parameter setting and system advantages are described from the FANUC arc welding robot.With the use of arc welding robot to weld the frame,to improve the welding quality,stability,efficiency,and to creat conditions for arc welding on the human body injury prevention.With the Application of arc welding robot in welding field, greatly promoted the development of welding automation technology.%介绍了FANUC弧焊机器人系统在奇瑞车架焊接上的应用.从FANUC弧焊机器人焊接控制系统硬件构成、程序框图、焊接指令、焊接参数设置以及系统优点等方面进行了阐述.使用孤焊机器人对车架进行焊接,为提高焊接质量、稳定性、工作效率,预防弧焊对人体的伤害创造了条件.弧焊机器人在焊接领域的应用,大大推动了自动化焊接技术的发展.

  12. Determination of input/output characteristics of full-bridge AC/DC/DC converter for arc welding

    OpenAIRE

    Stefanov, Goce; Karadzinov, Ljupco; Sarac, Vasilija; Cingoski, Vlatko; Gelev, Saso

    2016-01-01

    This paper describes the design and practical implementation of AC/DC/DC converter in mode of arc welding. An analysis of the operation of AC/DC/DC converter and its input/output characteristics are determined with computer simulations. The practical part is consisted of AC/DC/DC converter prototype for arc welding with output power of 3 kW and switching frequency of 64 kHz. The operation of AC/DC/DC converter is validated with experimental measurements.

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

    Energy Technology Data Exchange (ETDEWEB)

    Ramazani, A., E-mail: ali.ramazani@iehk.rwth-aachen.de [Department of Ferrous Metallurgy, RWTH Aachen University, D-52072 Aachen (Germany); Mukherjee, K. [Department of Ferrous Metallurgy, RWTH Aachen University, D-52072 Aachen (Germany); Abdurakhmanov, A. [Welding and Joining Institute, RWTH Aachen University, D-52072 Aachen (Germany); Prahl, U. [Department of Ferrous Metallurgy, RWTH Aachen University, D-52072 Aachen (Germany); Schleser, M.; Reisgen, U. [Welding and Joining Institute, RWTH Aachen University, D-52072 Aachen (Germany); Bleck, W. [Department of Ferrous Metallurgy, RWTH Aachen University, D-52072 Aachen (Germany)

    2014-01-01

    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.

  14. 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.

  15. Parametric studies on tensile strength in joining AA6061- T6 and AA7075-T6 by gas metal arc welding process

    Science.gov (United States)

    Ishak, M.; Noordin, N. F. M.; Shah, L. H.

    2015-12-01

    Proper selection of the welding parameters can result in better joining. In this study, the effects of various welding parameters on tensile strength in joining dissimilar aluminum alloys AA6061-T6 and AA7075-T6 were investigated. 2 mm thick samples of both base metals were welded by semi-automatic gas metal arc welding (GMAW) using filler wire ER5356. The welding current, arc voltage and welding speed were chosen as variables parameters. The strength of each specimen after the welding operations were tested and the effects of these parameters on tensile strength were identified by using Taguchi method. The range of parameter for welding current were chosen from 100 to 115 A, arc voltage from 17 to 20 V and welding speed from 2 to 5 mm/s. L16 orthogonal array was used to obtained 16 runs of experiments. It was found that the highest tensile strength (194.34 MPa) was obtained with the combination of a welding current of 115 A, welding voltage of 18 V and welding speed of 4 mm/s. Through analysis of variance (ANOVA), the welding voltage was the most effected parameter on tensile strength with percentage of contribution at 41.30%.

  16. Dynamic cooling during laser skin welding

    Science.gov (United States)

    Fried, Nathaniel M.; Walsh, Joseph T., Jr.

    1999-06-01

    Cryogen spray cooling of the tissue surface was investigated for laser welding applications. Benefits include reduced thermal damage to the papillary dermis and reduced operation time. Two-cm-long, full-thickness incisions were made on the backs of guinea pigs, in vivo. India ink was used as an absorber and clamps were used to appose the incision edges. Continuous-wave, 1.06-μm, Nd:YAG laser radiation was scanned over the incisions, producing ~100 ms pulses. A 4-mm-diameter laser spot was used with a constant power of 16 W. The total operation time was 60 or 120 s. Cryogen was delivered in spurt durations of 20, 60, or 100 ms, with 2 or 4 s between spurts. The working distance was approximately 12 cm, and the spray covered an area of about 5.0 x 5.0 cm. Control welds were irradiated for 20, 40, or 60 s. Total operation times were reduced from 10 min without dynamic cooling to 1 min with dynamic cooling. Optimal tensile strength was 1.7 +/- 0.7 kg/cm2, comparible to stengths of 2.1 +/- 0.7 kg/cm2 reported in previous studies without cryogen cooling (p>0.25). Thermal damage in the papillary dermis measured 320 +/- 80 μm.

  17. Effect of Weld Characteristic on Mechanical Strength of Laser-Arc Hybrid-Welded Al-Mg-Si-Mn Aluminum Alloy

    Science.gov (United States)

    Zhang, Chen; Gao, Ming; Jiang, Ming; Zeng, Xiaoyan

    2016-11-01

    Laser-arc hybrid welding (LAHW) was employed to improve the tensile properties of the joints of 8-mm-thick Al-Mg-Si-Mn alloy (AA6082) using Al-5Mg filler wire. The weld microstructures were examined by scanning electron microscope, electron backscattered diffraction, and transmission electron microscopy in detail. The LAHW joints with pore-free and high-tensile performances were obtained. The strength enhancement of the fusion zone and heat-affected zone in the LAHW joint was mainly attributed to the grain refinement strengthening and the precipitation strengthening, respectively. The microstructure characteristics were related to the effects of laser-arc interaction on the energy transfer within the molten pool. The arc caused the majority of laser energy to dissipate out of the keyhole, and then it reduced the heat input. The lower heat input refined the grain size, weakened the overaging effect, and thus improved the tensile strength.

  18. Effects of arc-ultrasonic on pores distribution and tensile property in TIG welding joints of MGH956 alloy

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Qiang, E-mail: zhuqiang@ujs.edu.cn [School of Material Science and Engineering, Jiangsu University, Zhenjiang (China); Lei, Yu-cheng [School of Material Science and Engineering, Jiangsu University, Zhenjiang (China); State Key Laboratory of Advanced Welding and Joining, Harbin Institute of Technology, Harbin (China); Wang, Yunlong; Huang, Wei; Xiao, Bo; Ye, Yi-min [School of Material Science and Engineering, Jiangsu University, Zhenjiang (China)

    2014-12-15

    MGH956, a kind of oxide dispersion strengthened (ODS) alloy, which is considered as candidate structural material for advanced nuclear systems because of its excellent radiation resistance and high-temperature capability. However, pores in fusion welding joints seriously reduced the quality and performance of the joint and structure. Arc-ultrasonic technology was applied in this research in order to prevent pores and improve tensile strength. The results showed that the excitation current of arc-ultrasonic has great effect on the pores distribution and tensile property. When it is increased to 20 A or 30 A, few pores are in the joint and the tensile strength (about 550 MPa) is also improved. When the arc-ultrasonic frequency decreased from 60 kHz to 30 kHz, bubbles floated outside more easily, the tensile strength is increased to about 543 MPa. But arc-ultrasonic has little influence on weld joints microhardness change.

  19. 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.

  20. Enhanced narrow gap pipeline welding using computer control and through-the-arc tracking technology

    Energy Technology Data Exchange (ETDEWEB)

    Laing, B.S. [CRC-Evans Automatic Welding, Houston, TX (United States)

    1992-12-31

    The CRC-Evans automatic welding system has been used in the construction of more than 15000 miles of onshore and offshore pipelines. This system has normally employed the short circuit mode of metal transfer. Recent application of computer technology has made it possible to increase welding speed of the root pass by 50 percent. The internal welding machine (IWM) was improved by the use of a computer control system based on the 8 bit, 12 MHz, Intel 80C152 central processing unit (CPU). Serial communication was established among several CPUs with the protocol called carrier sense, multiple access with collision detection (CSMA/CD). It was demonstrated that in ideal summer prairie conditions, daily production rates with use of computer control exceeded past experience. It was estimated that in less favourable conditions, arc time for an NPS 42 pipe would be reduced from 1.46 to 0.92 minutes and an NPS 48 from 1.67 to 1.12 minutes. It was concluded that computer control would not only help reduce construction costs but also help accomplish tasks in the short weather window for winter projects. 5 figs.

  1. 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)

  2. Urinary β2 Microglobulin in Workers Exposed to Arc Welding Fumes

    Directory of Open Access Journals (Sweden)

    Khosro Sadeghniiat-Haghighi

    2011-11-01

    Full Text Available Welding is a process in which two or more metals are attached by the use of heat and, in some cases, pressure. Direct exposure and inhalation of welding fumes causes acute and chronic side effects in humans. Kidney damage is one of these important side effects. β2 microglobulin is an 11.8 kilodalton protein and levels increase in the case of some inflammatory and viral diseases, or kidney malfunction and autoimmune diseases. In this study measurements of β2 microglobulin were used as a criterion for assessing effects on the kidneys of workers exposed to welding fumes. The study population were electric arc welders in an industrial plant in Tehran, Iran. For control we selected workers who did not have any exposure to welding fumes. Both groups were selected on the basis of a questionnaire and the consideration of criteria for inclusion and exclusion. In the end 50 cases and 50 controls were chosen. A urine sample was collected from all participants and urinary pH was set to between 6-8 using NaOH (1M. Sample transportation to the laboratory complied with the related standards. The samples were assessed using the ORG 5BM kit. For quantitative assessment of β2 microglobulin we used the Enzyme-linked Immunosorbent Assay (ELISA method. The ages of the welders ranged from 21 to 48 years (mean=30.5±5.9 yrs and of controls from 23 to 56 years (mean=31.8±5.9 yrs. Mean employment duration was 7.86±5.01years (range 2 to 27 years for welders. Mean β2 microglobulin level was 0.10±0.096 μg/ml in welders and 0.11±0.06 in controls. This difference was not statistically significant (P=0.381. In conclusion we don't find that exposure to electric arc welding fumes cause a significant change in urinary β2 microglobulin compared to the control group.

  3. Characterisation of Dynamic Mechanical Properties of Resistance Welding Machines

    DEFF Research Database (Denmark)

    Wu, Pei; Zhang, Wenqi; Bay, Niels

    2005-01-01

    The dynamic mechanical properties of a resistance welding machine have significant influence on weld quality, which must be considered when simulating the welding process numerically. However, due to the complexity of the machine structure and the mutual coupling of components of the machine system...... characterizing the dynamic mechanical characteristics of resistance welding machines is suggested, and a test set-up is designed determining the basic, independent machine parameters required in the model. The model is verified by performing a series of mechanical tests as well as real projection welds......., it is very difficult to measure or calculate the basic, independent machine parameters required in a mathematical model of the machine dynamics, and no test method has so far been presented in literature, which can be applied directly in an industrial environment. In this paper, a mathematical model...

  4. Two-dimensional time-dependent modelling of fume formation in a pulsed gas metal arc welding process

    Science.gov (United States)

    Boselli, M.; Colombo, V.; Ghedini, E.; Gherardi, M.; Sanibondi, P.

    2013-06-01

    Fume formation in a pulsed gas metal arc welding (GMAW) process is investigated by coupling a time-dependent axi-symmetric two-dimensional model, which takes into account both droplet detachment and production of metal vapour, with a model for fume formation and transport based on the method of moments for the solution of the aerosol general dynamic equation. We report simulative results of a pulsed process (peak current = 350 A, background current 30 A, period = 9 ms) for a 1 mm diameter iron wire, with Ar shielding gas. Results showed that metal vapour production occurs mainly at the wire tip, whereas fume formation is concentrated in the fringes of the arc in the spatial region close to the workpiece, where metal vapours are transported by convection. The proposed modelling approach allows time-dependent tracking of fumes also in plasma processes where temperature-time variations occur faster than nanoparticle transport from the nucleation region to the surrounding atmosphere, as is the case for most pulsed GMAW processes.

  5. 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.

  6. 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.

  7. Influence of Shielding Gas Composition on the Properties of Flux-Cored Arc Welds of Plain Carbon Steel

    Directory of Open Access Journals (Sweden)

    Ramy Gadallah

    2012-01-01

    Full Text Available In this study, the influence of variation in the shielding gas composition on the weld properties of steel ST 37-3 was investigated. Six different shielding gas compositions in addition to pure argon (Ar and pure CO2 were studied in this work using flux cored arc welding (FCAW process. For bead-on-plate (B.O.P specimens pure Ar shielding gas has excellent arc stability; however, with increase of the CO2 percent in the shielding gas compositions, the arc stability becomes noisy (unstable arc especially for pure CO2 . 75% Ar – 25% CO2 shielding gas composition has the optimum deposition rate among other shielding gases for B.O.P. Furthermore, for complete real welded joints, the absorbed energy in the Charpy impact toughness test of weld metal (W.M decreases with increase of the CO2 percent in the shielding gas composition. Additionally, the hardness of W.M decreases with the increase of the CO2 percent in the shielding gas composition.

  8. Development and Testing of an Experimental Polysensory Instructional System for Teaching Electric Arc Welding Processes. Report No. 24. Final Report.

    Science.gov (United States)

    Sergeant, Harold A.

    The population of the study consisted of 15 high school industrial arts students, 10 freshman and sophomore college students, and 10 adults. A polysensory, self-pacing instructional system was developed which included (1) pretests and post tests, (2) a general instruction book, (3) equipment to practice arc welding, (4) programed instruction…

  9. 双丝埋弧焊的应用及发展%Application and Development of Double-wire Submerged Arc Welding

    Institute of Scientific and Technical Information of China (English)

    杨芙; 许强; 柏久阳; 张文明

    2012-01-01

    对单双丝埋弧焊焊接工艺和接头性能进行了对比分析,阐述了双丝埋弧焊替代单丝埋弧焊的可行性.论述了双丝埋弧焊的工艺技术及发展状况,提出了双丝埋弧焊的高效性为其快速发展提供了广泛空间.最后点明了双丝埋弧焊现如今存在的问题和未来的发展方向.%The single and double-wire submerged arc welding process and joint properties were analyzed. The feasibility of two-wire submerged arc welding instead of the single-wire submerged arc welding was elaborated. The double wire submerged arc welding technology and development condition was discussed. The double wire submerged arc welding efficiency of double wire submerged arc welding can provide a broad space for the rapid development. The double wire submerged arc welding of existing problems and future development direction were pointed out.

  10. Dynamic behavior of the weld pool in stationary GMAW

    Directory of Open Access Journals (Sweden)

    Soulié F.

    2010-06-01

    Full Text Available Because hump formation limits welding productivity, better understanding of the humping phenomena during the welding process is needed to access to process modifications that decrease the tendency for hump formation and then allow higher productivity welding. From a physical point of view, the mechanism identified is the Rayleigh instability initiated by strong surface tension gradient which induces a variation of kinetic flow. But the causes of the appearance of this instability are not yet well explained. Because of the phenomena complex and multi-physics, we chose in first step to conduct an analysis of the characteristic times involved in weld pool in pulsed stationary GMAW. The goal is to study the dynamic behavior of the weld pool, using our experimental multi physics approach. The experimental tool and methodology developed to understand these fast phenomena are presented first: frames acquisition with high speed digital camera and specific optical devices, numerical library. The analysis of geometric parameters of the weld pool during welding operation are presented in the last part: we observe the variations of wetting angles (or contact lines angles, the base and the height of the weld pool (macro-drop versus weld time.

  11. Prediction of Welded Joint Strength in Plasma Arc Welding: A Comparative Study Using Back-Propagation and Radial Basis Neural Networks

    Science.gov (United States)

    Srinivas, Kadivendi; Vundavilli, Pandu R.; Manzoor Hussain, M.; Saiteja, M.

    2016-09-01

    Welding input parameters such as current, gas flow rate and torch angle play a significant role in determination of qualitative mechanical properties of weld joint. Traditionally, it is necessary to determine the weld input parameters for every new welded product to obtain a quality weld joint which is time consuming. In the present work, the effect of plasma arc welding parameters on mild steel was studied using a neural network approach. To obtain a response equation that governs the input-output relationships, conventional regression analysis was also performed. The experimental data was constructed based on Taguchi design and the training data required for neural networks were randomly generated, by varying the input variables within their respective ranges. The responses were calculated for each combination of input variables by using the response equations obtained through the conventional regression analysis. The performances in Levenberg-Marquardt back propagation neural network and radial basis neural network (RBNN) were compared on various randomly generated test cases, which are different from the training cases. From the results, it is interesting to note that for the above said test cases RBNN analysis gave improved training results compared to that of feed forward back propagation neural network analysis. Also, RBNN analysis proved a pattern of increasing performance as the data points moved away from the initial input values.

  12. 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.

  13. KEYHOLE IMAGE PROCESSING OF VARIABLE POLARITY PLASMA ARC WELDING BASED ON WAVELET TRANSFORM

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to realize the feedback control for variable polarity plasma arc welding (VPPAW) formation in the welding process, the geometrical sizes of the keyhole image must be extracted. With the properties of multiscale edge through the wavelet theory, the edge points were detected by getting the maximum modules of the gradient vector in the dircetion towards which the gradient vector points in the image plane. At coarse scales, the local maxima of modules have different positions and only detected the sharp edge. At fine scale, there are many maxima created by the image noise. The best scale where the edges are well discriminated from noises is discussed by the multiscale transform. At last, a new method of peak analysis for threshold selection is provided. It is based on the wavelet transform which provides a multiscale analysis of the information of the histogram. Many experiments show these ways are effective for the keyhole image to get the geometry parameters of the keyhole in the real-time VPPAW image processing.

  14. 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.

  15. 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.

  16. Control of Cr6+ emissions from gas metal arc welding using a silica precursor as a shielding gas additive.

    Science.gov (United States)

    Topham, Nathan; Wang, Jun; Kalivoda, Mark; Huang, Joyce; Yu, Kuei-Min; Hsu, Yu-Mei; Wu, Chang-Yu; Oh, Sewon; Cho, Kuk; Paulson, Kathleen

    2012-03-01

    Hexavalent chromium (Cr(6+)) emitted from welding poses serious health risks to workers exposed to welding fumes. In this study, tetramethylsilane (TMS) was added to shielding gas to control hazardous air pollutants produced during stainless steel welding. The silica precursor acted as an oxidation inhibitor when it decomposed in the high-temperature welding arc, limiting Cr(6+) formation. Additionally, a film of amorphous SiO(2) was deposited on fume particles to insulate them from oxidation. Experiments were conducted following the American Welding Society (AWS) method for fume generation and sampling in an AWS fume hood. The results showed that total shielding gas flow rate impacted the effectiveness of the TMS process. Increasing shielding gas flow rate led to increased reductions in Cr(6+) concentration when TMS was used. When 4.2% of a 30-lpm shielding gas flow was used as TMS carrier gas, Cr(6+) concentration in gas metal arc welding (GMAW) fumes was reduced to below the 2006 Occupational Safety and Health Administration standard (5 μg m(-3)) and the efficiency was >90%. The process also increased fume particle size from a mode size of 20 nm under baseline conditions to 180-300 nm when TMS was added in all shielding gas flow rates tested. SiO(2) particles formed in the process scavenged nanosized fume particles through intercoagulation. Transmission electron microscopy imagery provided visual evidence of an amorphous film of SiO(2) on some fume particles along with the presence of amorphous SiO(2) agglomerates. These results demonstrate the ability of vapor phase silica precursors to increase welding fume particle size and minimize chromium oxidation, thereby preventing the formation of hexavalent chromium.

  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.

    2016-05-01

    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.

  18. 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.

  19. 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.

  20. Direct probing of anode arc root dynamics and voltage instability in a dc non-transferred arc plasma jet

    Science.gov (United States)

    Ghorui, S.; Tiwari, N.; Meher, K. C.; Jan, A.; Bhat, A.; Sahasrabudhe, S. N.

    2015-12-01

    The transient dynamics of the anode arc root in a dc non-transferred arc plasma torch is captured through fast photography and directly correlated with the associated voltage instability for the first time. The coexistence of multiple arc roots, the transition to a single arc root, root formation and extinction are investigated for the steady, takeover and re-strike modes of the arc. Contrary to the usual concept, the emerging plasma jet of a dc non-transferred arc plasma torch is found to carry current. An unusually long self-propelled arc plasma jet, a consequence of the phenomenon, is demonstrated.

  1. Weldpool flow visualization studies during gas tungsten arc welding of steel and aluminum.

    OpenAIRE

    Schupp, Peter E.

    1992-01-01

    Approved for public release; distribution is unlimited. A flow visualization study of current distribution effects on weld pool stirring in GTA steel welds is presented using a pulsed ultraviolet laser vision system. Weld pool stirring is almost eliminated in HY-80 steel by the use of symmetric current flow path within the weld samples. Periodic radial surface pulses are observed at low currents in stationary welds while flows of turbulent nature are observed at higher cu...

  2. Measurement of Dynamic Resistance in Resistance Spot Welding

    DEFF Research Database (Denmark)

    Wu, Pei; Zhang, Wenqi; Bay, Niels

    Through years, the dynamic resistance across the electrodes has been used for weld quality estimation and contact resistance measurement. However, the previous methods of determining the dynamic resistance were mostly based on measuring the voltage and current on the secondary side...... of the transformer in resistance welding machines, implying defects from induction noise and interference with the leads connected to the electrodes for measuring the voltage. In this study, the dynamic resistance is determined by measuring the voltage on the primary side and the current on the secondary side......, as another application, the proposed method is used to measure the faying surface contact resistance....

  3. Design for low-cost gas metal arc weld-based aluminum 3-D printing

    Science.gov (United States)

    Haselhuhn, Amberlee S.

    Additive manufacturing, commonly known as 3-D printing, has the potential to change the state of manufacturing across the globe. Parts are made, or printed, layer by layer using only the materials required to form the part, resulting in much less waste than traditional manufacturing methods. Additive manufacturing has been implemented in a wide variety of industries including aerospace, medical, consumer products, and fashion, using metals, ceramics, polymers, composites, and even organic tissues. However, traditional 3-D printing technologies, particularly those used to print metals, can be prohibitively expensive for small enterprises and the average consumer. A low-cost open-source metal 3-D printer has been developed based upon gas metal arc weld (GMAW) technology. Using this technology, substrate release mechanisms have been developed, allowing the user to remove a printed metal part from a metal substrate by hand. The mechanical and microstructural properties of commercially available weld alloys were characterized and used to guide alloy development in 4000 series aluminum-silicon alloys. Wedge casting experiments were performed to screen magnesium, strontium, and titanium boride alloying additions in hypoeutectic aluminum-silicon alloys for their properties and the ease with which they could be printed. Finally, the top performing alloys, which were approximately 11.6% Si modified with strontium and titanium boride were cast, extruded, and drawn into wire. These wires were printed and the mechanical and microstructural properties were compared with those of commercially available alloys. This work resulted in an easier-to-print aluminum-silicon-strontium alloy that exhibited lower porosity, equivalent yield and tensile strengths, yet nearly twice the ductility compared to commercial alloys.

  4. 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.

    2016-10-01

    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.

  5. Investigation in the use of plasma arc welding and alternative feedstock delivery method in additive manufacture

    Science.gov (United States)

    Alhuzaim, Abdullah F.

    The work conducted for this thesis was to investigate the use of plasma arc welding (PAW) and steel shot as a means of additive manufacturing. A robotic PAW system and automatic shot feeder were used to manufacture linear walls approximately 100 mm long by 7 mm wide and 20 mm tall. The walls were built, layer-by-layer, on plain carbon steel substrate by adding individual 2.5 mm diameter plain carbon steel shot. Each layer was built, shot-by-shot, using a pulse of arc current to form a molten pool on the deposit into which each shot was deposited and melted. The deposition rate, a measure of productivity, was approximately 50 g/hour. Three walls were built using the same conditions except for the deposit preheat temperature prior to adding each new layer. The deposit preheat temperature was controlled by allowing the deposit to cool after each layer for an amount of time called the inter-layer wait time. The walls were sectioned and grain size and hardness distribution were measured as a function of wall height. The results indicated that, for all specimens, deposit grain size increased and hardness decreased as wall height increased. Furthermore, average grain size decreased and hardness increased as interlayer wait time increased. An analytical heat flow model was developed to study the influence of interlayer wait time on deposit temperature and therefore grain size and hardness. The results of the model indicated that as wall height increased, the rate of deposit heat removal by conduction to the substrate decreased leading to a higher preheat temperature after a fixed interlayer wait time causing grain size to increase as wall height increased. However, the model results also show that as wall height increased, the deposit surface area from which heat energy is lost via convection and radiation increased. The model also demonstrated that the use of a means of forced convection to rapidly remove heat from the deposit could be an effective way to boost

  6. Waveform control of CO2 arc welding spatter on IGBT inverter arc welding power%IGBT逆变弧焊电源CO2气体保护焊飞溅的波形控制

    Institute of Scientific and Technical Information of China (English)

    蔡建刚; 曹小军; 陈兆兴; 郑复晓

    2013-01-01

    With the development of inverter welding power and the application of digital technology, inverter CO2 gas shielded arc welding power supply can adjust the welding power source output current and voltage to control the droplet transfer, improve weld forming, reduce the spatter. According to the different stage requirements of droplet transfer, the welding current and voltage control signal were produced. By waveform control realizes regulate short -circuit current rising velocity, reduce the short circuit - current peak, reduce the short - circuit explosion energy, reduce the number of instantaneous short -circuit, through the liquid bridge necking voltage rising rate in the short - circuit late to cut short - circuit current, eliminate electrical explosion energy. These can reduce effectively the splashing quantity of CO2 gas shielded arc welding short - circuit transfer, provide powerful guarantee for design and implementation of low spatter CO2 gas shielded arc welding.%随着逆变焊机的发展和数字技术的应用,逆变CO2气体保护焊电源可通过调节焊接电源输出的电流与电压来控制熔滴过渡,改善焊缝成形,降低飞溅.根据熔滴过渡不同阶段的要求产生电流与电压控制信号,进行波形控制可实现调节短路电流上升速度,以减小短路峰值电流,降低短路爆炸能量;减少瞬时短路的次数;通过短路后期液桥颈缩电压上升率切断短路电流,消除电爆炸能量.以此有效减少CO2气体保护焊短路过渡产生的飞溅量,为低飞溅CO2气体保护焊的设计与实现提供有力保证.

  7. Improved microstructure and mechanical properties in gas tungsten arc welded aluminum joints by using graphene nanosheets/aluminum composite filler wires.

    Science.gov (United States)

    Fattahi, M; Gholami, A R; Eynalvandpour, A; Ahmadi, E; Fattahi, Y; Akhavan, S

    2014-09-01

    In the present study, different amounts of graphene nanosheets (GNSs) were added to the 4043 aluminum alloy powders by using the mechanical alloying method to produce the composite filler wires. With each of the produced composite filler wires, one all-weld metal coupon was welded using the gas tungsten arc (GTA) welding process. The microstructure, mechanical properties and fracture surface morphology of the weld metals have been evaluated and the results are compared. As the amount of GNSs in the composition of filler wire is increased, the microstructure of weld metal was changed from the dendritic structure to fine equiaxed grains. Furthermore, the tensile strength and microhardness of weld metal was improved, and is attributed to the augmented nucleation and retarded growth. From the results, it was seen that the GNSs/Al composite filler wire can be used to improve the microstructure and mechanical properties of GTA weld metals of aluminum and its alloys.

  8. Some Studies of Optimal Process Parameters For Solid Wire Gas Metal Arc Welding Using Neural Network Technique And Simulation Using Ansys

    Directory of Open Access Journals (Sweden)

    Saritprava Sahoo

    2013-08-01

    Full Text Available GMAW (Gas Metal Arc Welding is an arc welding process which is widely used in industry to join the metals. In this present work we have investigated the effect of varying welding parameters on the weld bead quality of Mild Steel flat having 12mm thickness. The chosen input parameters for the study are Welding Voltage, Welding Current and the travel speed of welding torch. The output parameters chosen are Weld Bead Width, Weld Bead Height, Depth of Penetration and Depth of Heat Affected Zone (HAZ. The four levels of experimental set-ups for each of the input parameters are considered and other process parameters are kept constant for the study. Hence the total numbers of experimental set-ups are 64 and the corresponding values of output parameters are found. As this is a Multi-Response Problem, it is being optimized to Single-Response Problem using Weighted Principal Components (WPC Method. Artificial Neural Networks (sANN, Error Back Propagation Procedure is being used for the prediction of optimal process parameters for GMAW process in this present work. The finite element analysis of residual stresses in butt welding of two similar plates is performed with the ANSYS software.

  9. 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.

  10. Measurement of dynamic resistance in resistance spot welding

    Institute of Scientific and Technical Information of China (English)

    Wu Pei; Lü Jiaheng; Wenqi Zhang; Niels Bay

    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 influenced by inductive noise caused by the high welding current. In this study, the dynamic resistance is determined by measuring the voltage at primary side and current at secondary side. This increases the accuracy of measurement because of higher signal-noise ratio, and allows to apply to in-process system without any wires connected to electrodes.

  11. 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 influenced by inductive noise caused by the high welding current. In this study, the dynamic resistance is determined by measuring the voltage at primary side and current at secondary side. This increases the accuracy of measurement because of higher signal-noise ratio, and allows to apply to in...

  12. 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.

  13. 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.

  14. 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)

  15. 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.

  16. 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.

  17. Multi-modal human-machine interface of a telerobotic system for remote arc welding

    Institute of Scientific and Technical Information of China (English)

    Li Haichao; Gao Hongming; Wu Lin; Zhang Guangjun

    2008-01-01

    In telerobotic system for remote welding, human-machine interface is one of the most important factor for enhancing capability and efftciency. This paper presents an architecture design of human-machine interface for welding telerobotic system: welding multi-modal human-machine interface. The human-machine interface integrated several control modes, which are namely shared control, teleteaching, supervisory control and local autonomous control. Space mouse, panoramic vision camera and graphics simulation system are also integrated into the human-machine interface for welding teleoperation. Finally, weld seam tracing and welding experiments of U-shape seam are performed by these control modes respectively. The results show that the system has better performance of human-machine interaction and complexity environment welding.

  18. 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…

  19. A method to simulate multilayer welding process: Node dynamic relaxation method

    Institute of Scientific and Technical Information of China (English)

    Gao Jiashuang; Yang Jianguo; Fang Hongyuan; Hu Junfeng; Wang Tao

    2009-01-01

    A new method called node dynamic relaxation is proposed to simulate multilayer welding. A two dimensional plane strain model for multilayer welding is simulated and the results show that mesh distortion can be decreased, and it is also found that the node dynamic relaxation is a kind of method to calculate welding deformation accurately by comparing experiment results with simulation results.

  20. 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.

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

    Science.gov (United States)

    Bachmann, B.; Siewert, E.; Schein, J.

    2012-05-01

    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 30 000 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.

  2. Welding arc radiation hazard and protection%电弧焊弧光幅射的危害与防护

    Institute of Scientific and Technical Information of China (English)

    欧泽兵

    2011-01-01

    在分析焊接产生的紫外线、可见光和红外线辐射特点及其危害的基础上,依据标准要求提出防护装备的使用要求以及通过培训以提高焊接操作者自我防护意识的建议,从而最大限度地减少焊接弧光对焊接操作者的危害.%The paper presents suggestion on welding hazards protection based on characteristics of UV.IR,visible lights and related standards.To minimize welding arc hazards via improving welders' safety consciousness by hazards analysis and protection training.

  3. Normalizing effect on fatigue crack propagation at the heat-affected zone of AISI 4140 steel shielded metal arc weldings

    Directory of Open Access Journals (Sweden)

    B. Vargas-Arista

    2013-01-01

    Full Text Available The fractography and mechanical behaviour of fatigue crack propagation in the heat-affected zone (HAZ of AISI 4140 steel welded using the shielded metal arc process was analysed. Different austenitic grain size was obtained by normalizing performed at 1200 °C for 5 and 10 hours after welding. Three point bending fatigue tests on pre-cracked specimens along the HAZ revealed that coarse grains promoted an increase in fatigue crack growth rate, hence causing a reduction in both fracture toughness and critical crack length, and a transgranular brittle final fracture with an area fraction of dimple zones connecting cleavage facets. A fractographic analysis proved that as the normalizing time increased the crack length decreased. The increase in the river patterns on the fatigue crack propagation in zone II was also evidenced and final brittle fracture because of transgranular quasicleavage was observed. Larger grains induced a deterioration of the fatigue resistance of the HAZ.

  4. Experimental Investigation on the Performance of Armour Grade Q&T Steel Joints Fabricated by Flux Cored Arc Welding with Low Hydrogen Ferritic Consumables

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

    Quenched and Tempered (Q&T) steels are widely used in the construction of military vehicles due to its high strength to weight ratio and high hardness. These steels are prone to hydrogen induced cracking (HIC) and softening in the heat affected zone (HAZ) after welding. The use of austenitic stainless steel (ASS) consumables to weld the above steel was the only available remedy to avoid HIC because of higher solubility for hydrogen in austenitic phase. Recent studies revealed that low hydrogen ferritic (LHF) steel consumables can also be used to weld Q&T steels, which can give very low hydrogen levels in the weld deposits and required resistance against cold cracking. Hence, in this investigation an attempt has been made to study the performance of armour grade Q&T steel joints fabricated by flux cored arc welding with LHF steel consumables. Two different consumables namely (i) austenitic stainless steel and (ii) low hydrogen ferritic steel have been used to fabricate the joints by flux cored arc welding (FCAW) process. The joints fabricated by LHF consumable exhibited superior transverse tensile properties due to the presence of ferrite microstructure in weld metal. The joints fabricated by ASS consumable showed higher impact toughness due to the presence of austenitic phase in weld metal microstructure. The HAZ softening in coarse grain heat affected zone (CGHAZ) is less in the joints fabricated using LHF consumable due to the lower heat input involved during fabrication compared to the joints fabricated using ASS consumables.

  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. 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...

  7. Study on Arc Stability Evaluation Index of CO2 Arc Welding Process%CO2气体保护焊电弧稳定性评价指标研究

    Institute of Scientific and Technical Information of China (English)

    李慧敏; 凌泽民; 何建

    2016-01-01

    The Hannover analyzer was used to acquire the signal result of voltage and current.The voltage-current waveform,probability distribution diagram of voltage and current (PDD) and frequency distribution of short-circuit time,arcing time,weighted arcing time,and the short-circuit cycle time (CFD) were automatically generated.The main influenced factors of arc droplet transfer and weld seam formation based on the analysis of the electrical characteristics of the arc process were obtained.The results show that the main factors which influence the arc process characteristics and weld appearance are weld current and arc voltage.Arc voltage influences the droplet diameter,stability of arc,spatter and the width of weld.When the arc voltage is lower,the transition process is unstable and the spatter is bigger.When the arc voltage is higher,mixed transition appears.When the arc voltage is 18V,the stability of arc is better.The welding current can affect wire melting speed,the frequency of transition,spatter,and weld seam quality and so on.When the current is lower,the broken arc phenomenon appears,and the fromation of weld seam is bad.While the higher welding current,the bigger spatter and the bad stability of the arc,and the invalid short circuit appear.When the welding current is 160A,smaller spatter and better weld seam formation can be obtained.%本试验采用汉诺威焊接质量分析仪对电弧电压和焊接电流信号进行采集,并自动生成电压电流波形图、电弧电压和焊接电流的概率密度分布图(PDD图)及短路时间、燃弧时间、加权燃弧时间、短路周期的频次分布图(CFD图),并分析电弧过程的电特性,找到熔滴过渡以及焊缝成形的主要影响因素.结果表明:电弧电压和电流对短路过渡有明显影响.电弧电压影响电弧稳定性、飞溅大小、焊缝熔宽等.电压偏低,过渡过程不稳定,飞溅较大;电压偏高,将会出现混合过渡;当电弧电压在18V时,电弧稳定性

  8. Automatic Submerged ARC Welding With Metal Power Additions to Increase Productivity and Maintain Quality

    Science.gov (United States)

    1986-06-01

    Manager of Welding Engineering PROPOSAL WELDING OF CARBON STEEL AND HY80 UTILIZING THE BULK WELDING PROCESS May 9, 1983 PREPARED BY: NEWPORT NEwS...12 joints with carbon steel and 12 with HY80 , utilizing three The joints will requirements of Benefits 1. Deposition times that different size double...of Joint Variations and Deposition Rates Filler Metal/Base Material Chemical Analyses; Carbon Steel /HIS Filler Metal/Base Material Chemical Analyses

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

    Science.gov (United States)

    Zoppetti, Nicola; Bogi, Andrea; Pinto, Iole; Andreuccetti, Daniele

    2015-02-01

    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.

  10. Economic Comparison of Laser-arc Hybrid Welding and MAG Welding of Steel Sheet%薄板激光-电弧复合焊接与电弧焊接的经济性对比分析

    Institute of Scientific and Technical Information of China (English)

    张欣

    2014-01-01

    laser-arc hybrid welding is combined with two different heat sources of laser and arc,described by the phys-ical processes of energy transport and by the obtained energy flow,which means that laser beam and arc simultaneous-ly act on the welding zone and that they affect and support each other. The research results show that the welding time laser-arc hybrid wielding of steel sheet is 25% of that of MAG welding, and filler wire cost is 23% of that of MAG welding.%激光-电弧复合焊接技术是将激光与电弧两种不同性质的热源复合在一起,同时作用于工件表面的新型焊接技术。研究结果表明,与电弧焊接技术相比,激光-电弧复合焊接具有焊接工时少、焊丝消耗低、经济效益大等特点,在薄板焊接上具有较大的优势。

  11. Laser-MIG Arc Hybrid Brazing-Fusion Welding of Al Alloy to Galvanized Steel with Different Filler Metals

    Institute of Scientific and Technical Information of China (English)

    Shujun WANG; Guoliang QIN; Yuhu SU

    2013-01-01

    Aluminum alloy plates were joined to galvanized steel sheets with lap joint by laser-MIG arc hybrid brazingfusion welding with AlSi5,AlSi12,AlMg5 filler wires,respectively.The influences of Si and Mg on the microstructure and mechanical properties of the brazed-fusion welded joint were studied.The increase of Si element in the fusion weld can make the grain refined,and increase the microhardness of the fusion weld.Therefore,the microhardness in fusion weld made from AlSi12 and AlSi5 filler wires can be up to 98.4 HV0.01and 96.8 HV0.01,which is higher than that from AlMg5 filler wire of 70.4 HV0.01.The highest tensile strength can reach 178.9 MPa made with AlMg5 filler wire.The tensile strength is 172.43 MPa made with AlSi5 filler wire.However,the lowest tensile strength is 144 MPa made with AlSi12 filler wire.The average thicknesses of the intermetallic compounds (IMCs) layer with AlSi5,AlSi12,AlMg5 filler wires are 1.49-2.64 μm.The lMCs layer made from AlSi5,AlSi12 filler wires are identified as FeAl2,Fe2Als,Fe4Al13 and Al0.5Fe3Si0.5,that from AlMg5 filler wire are identified as FeAl2,Fe2Al5 and Fe4Al13.

  12. Dynamic modeling and simulation for nonholonomic welding mobile robot

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Based on the Newton-Euler method, the dynamic behaviors of the left and right driving wheels and the robot body for the welding mobile robot were derived. In order to realize the combination control of body turning and slider adjustment, the dynamic behaviors of sliders were also investigated. As a result, a systematic and complete dynamic model for the welding mobile robot was constructed. In order to verify the effectiveness of the above model, a sliding mode tracking control method was proposed and simulated, the lateral error stabilizes between -0.2 mm and +0.2 mm, and the total distance of travel for the slider is consistently within ±2 mm. The simulation results verify the effectiveness of the established dynamic model and also show that the seam tracking controller based on the dynamic model has excellent performance in terms of stability and robustness. Furthermore, the model is found to be very suitable for practical applications of the welding mobile robot.

  13. 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...

  14. 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...

  15. Welding procedure qualification of automatic submerged arc welding with asbestos gasket for gas liquid separator%液气分离器石棉衬垫法埋弧自动焊焊接工艺评定

    Institute of Scientific and Technical Information of China (English)

    马世辉; 李小棒

    2013-01-01

    板厚8—12 mm的液气分离器筒体采用埋弧焊+焊条电弧焊的焊接工艺,生产效率低,工作量大,焊接质量不稳定.详述改进后的石棉板衬垫法埋弧自动焊焊接工艺评定过程,焊接工艺评定结果合格.继而在多台液气分离器产品推广应用,实践证明此改进工艺可操作性和适用性强,保证了焊接质量,取得了较好的效果.%Gas liquid separator of 8~12 mm plate thickness is welded in automatic submerged arc welding plus SMAW welding to be provided with low production efficiency,heavy workload,unstable welding quality.This paper details welding procedure qualification of automatic submerged arc welding with asbestos gasket and the results proved to be qualified,then popularization and application in the multiple gas liquid separator turned out to be strong maneuverability and applicability,ensured the welding quality and achieved good results.

  16. Effect of Ti-Al on microstructures and mechanical properties of plasma arc in-situ welded joint of SiCp/Al MMCs

    Institute of Scientific and Technical Information of China (English)

    LEI Yu-cheng; ZHANG Zhen; NIE Jia-jun; CHEN Xi-zhang

    2008-01-01

    The effect of Ti-Al on microstructures and mechanical properties of SiCp/Al MMC joints produced by plasma arc in-situ weld-alloying was investigated, in which argon-nitrogen mixture was used as plasma gases and Ti-Al alloy as filling composite. The results show that the formation of needle-like harmful phase Al4C3 is effectively prevented in the weld by in-situ weld-alloying/plasma arc welding with Ti-Al alloy sheet filler whose titanium content is more than 20%. The fluidity of molten pool is improved, and stable molten pool is gained for the addition of the Ti-Al alloy. The mechanical properties of welded joint are effectively enhanced by the compact-grain structure and the new reinforced composites such as Al3Ti, TiN, AlN and TiC welded joint. The test results of mechanical property show that the maximum tensile strength of welded joint gained by adding Ti-60Al alloy is up to 235 MPa. The factors influencing the tensile strength were also investigated.

  17. Research progress of laser welding process dynamic monitoring technology based on plasma characteristics signal

    Directory of Open Access Journals (Sweden)

    Teng WANG

    2017-02-01

    Full Text Available During the high-power laser welding process, plasmas are induced by the evaporation of metal under laser radiation, which can affect the coupling of laser energy and the workpiece, and ultimately impact on the reliability of laser welding quality and process directly. The research of laser-induced plasma is a focus in high-power deep penetration welding field, which provides a promising research area for realizing the automation of welding process quality inspection. In recent years, the research of laser welding process dynamic monitoring technology based on plasma characteristics is mainly in two aspects, namely the research of plasma signal detection and the research of laser welding process modeling. The laser-induced plasma in the laser welding is introduced, and the related research of laser welding process dynamic monitoring technology based on plasma characteristics at home and abroad is analyzed. The current problems in the field are summarized, and the future development trend is put forward.

  18. Numerical investigation of the effects of iron oxidation reactions on the fume formation mechanism in arc welding

    Science.gov (United States)

    Sanibondi, Paolo

    2015-09-01

    Fume formation during arc welding has been modelled using a stochastic approach taking into account iron oxidation reactions. The model includes the nucleation and condensation of Fe and FeO vapours, the reaction of gaseous O2 and O on the nanoparticle surface, the coagulation of the nanoparticles including a sintering time as a function of temperature and composition, assuming chemical equilibrium for species in the gaseous phase. Results suggest that fumes generated in gas metal arc welding with oxidizing shielding mixtures are composed of aggregates of primary particles that are nucleated from gas-phase FeO and further oxidized to Fe3O4 and Fe2O3 in the liquid and solid phase, respectively. The composition of the fumes at the end of the formation process depends on the relative initial concentration of Fe and O2 species in the gas mixture and on the diameter of the primary particles that compose the aggregates: as the oxidation reactions are driven by deposition of oxygen on nanoparticle surface, the oxidation of larger particles is slower than that of smaller particles because of their lower surface to volume ratio. Solid-state diffusion is limiting the oxidation process at temperatures lower than 1500 K, inducing the formation of not fully oxidized particles composed of Fe3O4.

  19. Analysis of effect of temperature gradients on surface-tension phenomena in gas-tungsten-arc welds

    Energy Technology Data Exchange (ETDEWEB)

    Lee, H.A.; Chien, P.S.J.

    1982-10-01

    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.

  20. 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.

  1. Submerged Arc Stainless Steel Strip Cladding—Effect of Post-Weld Heat Treatment on Thermal Fatigue Resistance

    Science.gov (United States)

    Kuo, I. C.; Chou, C. P.; Tseng, C. F.; Lee, I. K.

    2009-03-01

    Two types of martensitic stainless steel strips, PFB-132 and PFB-131S, were deposited on SS41 carbon steel substrate by a three-pass submerged arc cladding process. The effects of post-weld heat treatment (PWHT) on thermal fatigue resistance and hardness were evaluated by thermal fatigue and hardness testing, respectively. The weld metal microstructure was investigated by utilizing optical microscopy, scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). Results showed that, by increasing the PWHT temperature, hardness decreased but there was a simultaneous improvement in weldment thermal fatigue resistance. During tempering, carbide, such as (Fe, Cr)23C6, precipitated in the weld metals and molybdenum appeared to promote (Fe, Cr, Mo)23C6 formation. The precipitates of (Fe, Cr, Mo)23C6 revealed a face-centered cubic (FCC) structure with fine grains distributed in the microstructure, thereby effectively increasing thermal fatigue resistance. However, by adding nickel, the AC1 temperature decreased, causing a negative effect on thermal fatigue resistance.

  2. 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.

  3. 气保焊用药芯焊丝的发展趋势%Trends in development of flux-cored wires for gas-shielded arc welding

    Institute of Scientific and Technical Information of China (English)

    Masayuki NAGAMI; Tetsuya HASHIMOTO

    2007-01-01

    Arc welding technologies in Japan have been advanced steadily since the time when an application of covered electrodes was first examined in the shipbuilding industry about 90 years ago.The history of the arc welding technology has always been the history of the pursuit of higher "efficiency and speed" of welding processes.Welding materials,originally started with covered electrodes,have been developed into more efficient submerged arc welding materials and gas—shielded arc welding materials with which automatic welding and robotic welding can easily be conducted.The gas—shielded arc welding materials can be classified mainly into solid wires and flux—cored wires(FCWs),and of these wires,FCW has been increasing in uses year by year because of its excellent workability and efficiency.This article describes the recent trends in the development of FCWs which now hold the major position in the welding materials.A special focus is put on the FCWs for carbon steels.%90年前,日本的造船业开始使用药皮焊条.自此,日本的弧焊技术取得了长足进步.弧焊技术的历史是焊接工艺"高速度、高效率"的历史.自药皮焊条开始焊接材料已发展成为更高效的埋弧焊焊材和气保焊焊材,并能更容易地结合自动化焊接和机器人焊接.气保焊焊材主要分为实芯焊丝和药芯焊丝,药芯焊丝的应用因其出色的实用性和效率而逐年增加.介绍了药芯焊丝作为主要焊材的发展趋势,尤其是在碳钢焊接上的应用.

  4. Analysis of low energy arc discharge characteristics based on dynamic V-A characteristics model

    Institute of Scientific and Technical Information of China (English)

    JING Li-nan; WANG Li-gong

    2006-01-01

    Low energy arc discharge characteristics was analyzed based on dynamic V-A characteristics model. It draws conclusions that discharge time relates to the source voltage and the product of inductance and stable current, discharge time will increase when the source voltage increases; current reduce rate is in inverse proportion to the value of inductance; arc resistance when the arc occurs is the ratio of minimum arcing voltage to stable current. It also gains the expressions of arc resistance and arc power, arc resistance and arc power both increase as the source voltage increases and decrease as the value of inductance increases. Conclusions above mentioned are helpful to design intrinsically safe circuits.

  5. One Side Welding--Flux Development--and Study of Multiple Arc Behavior

    Science.gov (United States)

    1971-01-01

    containing 19% iron powder (977-39C). The top is flat and has good surface tie-in but the bottom is completely underfilled because of the lack of iron...electrodes in 1 1/2 inch ABS Gd. C. plate are slightly underfilled on top but the bottom has good shape. Cross sections of the welds show good contour...This weld shape should be avoided because of the possibility of voids and entrapped slag particles in the center of the weld between the two

  6. The ways of reliability enhancement of welded metal structures for critical applications in the conditions of low climatic temperatures

    Science.gov (United States)

    Saraev, Yu. N.; Bezborodov, V. P.; Gladkovsky, S. V.; Golikov, N. I.

    2016-11-01

    The paper studies how the energy parameters of an effective welding technology based on adaptive pulse-arc welding method influence the microstructure, mechanical characteristics and fatigue strength of low carbon steel 09G2S welded joint. It is established that the application of the adaptive pulse-arc welding method with modulated current (CMW) as compared to the welding method with direct current (DCW) allows one to obtain a welded joint of this steel with high reserve impact strength, dynamic fracture toughness and fatigue strength of metallic structures at operation temperatures up to -60°C.

  7. Development of an Ultralight Pulse Gas Metal ARC Welding System for Shipyard Applications

    Science.gov (United States)

    2007-07-27

    standard 200A OXO, Model AP20. Instrumentation included a calibrated analog ammeter (shunt, mV meter) and VOM (Simpson 260). Initial testing used...strength predicted based on the same correlation. In both cases, weld metal Charpy V-notch impact test results far exceeded minimum specification...Technology (CNST), work was conducted to specify, build, test , and production prove a light-weight, man-portable welding system as described above. The

  8. Application of Automatic Submerged -arc Welding in Girth Welding of Arch Rib of Tube Arch%埋弧自动焊在钢管拱拱肋环焊缝中的应用

    Institute of Scientific and Technical Information of China (English)

    宇文德成; 张丽惠

    2011-01-01

    Research purposes: According to the structural characteristics of the arch rib of the steel tube of polygonal line (arc shape) , this paper tries to find out the negative factors which affect the welding position, speed changes and structural mass balance when joining the segment of arch rib into the polygonal line (Arc shape) during automatic submerged - arc welding, and offers the solution to the problem with kinematic analysis and calculation for making the processing of arch rib of steel tube in workshop fulfilled by submerged - arc welding.Research conclusions:Based on the theoretical analysis and according to the actual production process, the negative factors were overcome by determining the reasonable support location of roller and properly configuring weight equalizer. Based on it, a method to do girth welding of polygonal line tube with submerged - arc welding was found. With this method, the 100% of automatic welding of girth joint in factory workshop can be realized, which is up to 90% of the full - bridge tube girth joint with features of less welding defects, stable welding quality and improving welding efficiency.%研究目的:根据钢管拱折线(弧形)拱肋的结构特点,找出将拱肋节段对接成折线(弧形)时,影响采用埋弧自动焊时焊点位置、速度变化和结构质量平衡的不利因素.并通过运动学分析与计算,提出解决问题的方法.使钢管拱拱肋厂内加工全部实现采用埋弧自动焊工艺.研究结论:根据理论分析,在实际生产过程中,采取确定滚轮合理的支撑位置及适当配置平衡重物这两种措施,克服了不利因素,摸索出了一套在滚轮架上用自动埋弧焊工艺焊接折线管对接环焊缝的方法,实现了工厂内加工环焊缝100%的自动化焊接,占全桥所有管对接环焊缝的90%以上,焊缝缺陷频率低、质量稳定、提高了工效.

  9. Effect of pulsed current micro plasma arc welding process parameters on fusion zone grain size and ultimate tensile strength of Inconel 625 sheets

    Institute of Scientific and Technical Information of China (English)

    Kondapalli Siva Prasad; Chalamalasetti Srinivasa Rao; Damera Nageswara Rao

    2012-01-01

    The paper focuses on developing mathematical models to predict grain size and ultimate tensile strength of pulsed current micro plasma arc welded Inconel 625 nickel alloy.Four factors,five levels,central composite rotatable design matrix is used to optimize the number of experiments.The mathematical models have been developed by response surface method.The adequacy of the models is checked by analysis of variance technique.By using the developed mathematical models,grain size and ultimate tensile strength of the joints can be predicted with 99%0 confidence level.Contour plots are drawn to study the interaction effect of pulsed current micro plasma arc welding parameters on fusion zone grain size and ultimate tensile strength of Inconel 625 weld ioints.

  10. Study on Control Methods of Welding Porosity in Laser-arc Hybrid Welding for High Nitrogen Steels%高氮钢激光-电弧复合焊接气孔控制方法研究

    Institute of Scientific and Technical Information of China (English)

    王力锋; 刘凤德; 刘薇娜; 田淼磊

    2016-01-01

    In order to master the control methods of welding porosity on laser-arc hybrid welding for high nitrogen steel, the effect of weld porosity on arc energy and laser energy and the vibration frequency are studied. Causes of welding porosity are analyzed in terms of porosity rate, and its effect is investigated on stability of welding processes through waveforms of current and voltage and droplet transfer. There is certain relevance between fluid flow in the melt pool and formation of welding porosity, and the influence on welding porosity is analyzed in terms of fluid flow in the melt pool. The keyhole is generated when laser power reaches up to a certain extent and condition of keyhole will affect porosity rate. Influence of porosity rate on condition of keyhole is analyzed according to keyhole's stress situation. The results shows that porosity rate of welding seam increased first and then decreased with the increasing of arc energy or laser energy, and porosity rate of welding seam is reduced to the lowest for just 0.49% while arc energy is 4 800 J (I=200 A,U=24 V) and the porosity rate of welding seam is only 0.14% when laser power is 2.8 kW, but porosity rate of welding seam is reduced greatly after work pieces are vibrated during hybrid welding. Porosity rate of welding seam decreased first and then increased with the increasing of vibration frequency. The number of welding porosity is inhibited efficiently by suitable arc energy or laser power, and inhibitory effect of welding porosity is best while vibration frequency amount to 35 Hz.%为了掌握高氮钢复合焊接气孔控制的有效方法,研究电弧能量、激光能量和振动频率对焊缝气孔的影响。从气孔率方面分析焊缝气孔的产生原因,并从电流和电压波形及熔滴过渡方面分析其对焊接过程稳定性的影响。熔池流动与焊缝气孔具有一定的关联性,并从熔池流动状态方面分析其对气孔的影响。激光匙孔的形成需要一

  11. Correlation of Arc Sound and Arc-sidewall Position in Narrow Gap MAG Welding%窄间隙MAG焊电弧声与电弧作用位置的相关性

    Institute of Scientific and Technical Information of China (English)

    兰虎; 张华军; 陈善本; 盛凯; 赵德龙

    2014-01-01

    电弧-侧壁距离控制是保证窄间隙熔化极活性气体保护焊(Narrow gap metal active gas welding, NG-MAG)侧壁熔合良好的关键。通过对NG-MAG脉冲立焊过程中电弧声的预处理和分析,发现其时域波形呈周期性“振铃”衰减特性,频率与焊接电源脉冲频率相同;电弧声能量的频域分布范围为0.3~12.0 kHz,且能量主要集中在0.3~3.0 kHz和9.0~12.0 kHz两个频带,频谱分布与电弧-侧壁距离高度相关。在此基础上,采用小波变换(Wavelet transform, WT)和联合时频分析(Joint time-frequency analysis, JTFA)实现对电弧声信号的降噪处理和时频分析,结果发现,伴随电弧-侧壁距离的逐渐增大,电弧声能量的低频分布始终存在,呈现“断续-连续-断续”分布特征;而高频分布出现在电弧-侧壁距离2.6 mm以上,呈现“断续-连续”分布特征。利用 NG-MAG 脉冲立焊电弧声的时频分布规律可实现对电弧作用位置的监测预警,为 NG-MAG 焊接过程状态监控提供一种途径。%The control of arc-sidewall distance is the key to ensure good sidewall fusion in the process of narrow gap metal active gas welding(NG-MAG) welding. Through pretreatment and analysis of arc sound in NG-MAG pulse vertical welding, it is found that there exists periodic “ringing” attenuation phenomenon in the time-domain waveform, and its frequency is equal to the pulse frequency of welding power. The frequency distribution of arc sound energy varies from 0.3 kHz to 12.0 kHz. And energy mainly concentrates in two bands, range of 0.3-3.0 kHz and 9.0-12.0 kHz. Spectrum distribution of arc sound is highly relevant to arc-sidewall distance. On this basis, noise reduction and time-frequency analysis of arc sound are achieved by use of wavelet transform(WT) and joint time-frequency analysis(JTFA). The results show that low-frequency energy distribution of arc sound is always present, show

  12. Microstructures and mechanical properties of Ti3Al/Ni-based superalloy joints arc welded with Ti–Nb and Ti–Ni–Nb filler alloys

    Directory of Open Access Journals (Sweden)

    Bingqing Chen

    2014-08-01

    Full Text Available Dissimilar joining of Ti3Al-based alloy to Ni-based superalloy has been carried out using gas tungsten arc (GTA welding technology with Ti–Nb and Ti–Ni–Nb filler alloys. The joint welded with the Ti–Nb filler alloy contained much less interfacial brittle phases than the one using the Ti–Ni–Nb filler alloy. The average room-temperature tensile strength of the joint welded with Ti–Nb was 202 MPa and the strength value of the one welded with Ti–Ni–Nb was 128 MPa. For both fillers, the weak links of the dissimilar joints were the weld/In718 interfaces. The presence of TiNi, TiNi3 and Ni3Nb intermetallic compounds in the joint welded with Ti–Ni–Nb induced microcracks at the weld/In718 interface and deteriorated the mechanical properties of the joint. And the adoption of the Ti–Nb filler alloy decreased the formation tendency of interfacial brittle phases to some extent and thus enhanced the tensile strength of the joint.

  13. 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.

  14. High Temperature Corrosion studies on Pulsed Current Gas Tungsten Arc Welded Alloy C-276 in Molten Salt Environment

    Science.gov (United States)

    Manikandan, M.; Arivarasu, M.; Arivazhagan, N.; Puneeth, T.; Sivakumar, N.; Murugan, B. Arul; Sathishkumar, M.; Sivalingam, S.

    2016-09-01

    Alloy C-276 is widely used in the power plant environment due to high strength and corrosion in highly aggressive environment. The investigation on high- temperature corrosion resistance of the alloy C-276 PCGTA weldment is necessary for prolonged service lifetime of the components used in corrosive environments. Investigation has been carried out on Pulsed Current Gas Tungsten Arc Welding by autogenous and different filler wires (ERNiCrMo-3 and ERNiCrMo-4) under molten state of K2SO4-60% NaCl environment at 675oC under cyclic condition. Thermogravimetric technique was used to establish the kinetics of corrosion. Weight gained in the molten salt reveals a steady-state parabolic rate law while the kinetics with salt deposits displays multi-stage growth rates. PCGTA ERNiCrMo-3 shows the higher parabolic constant compared to others. The scale formed on the weldment samples upon hot corrosion was characterized by using X-ray diffraction, SEM and EDAX analysis to understand the degradation mechanisms. From the results of the experiment the major phases are identified as Cr2O3, Fe2O3, and NiCr2O4. The result showed that weld fabricated by ERNiCrMo-3 found to be more prone to degradation than base metal and ERNiCrMo-4 filler wire due to higher segregation of alloying element of Mo and W in the weldment

  15. 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.

  16. Vision-based detection of weld pool width in TIG welding of copper-clad aluminum cable

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In order to realize automatic control of the width of weld pool, a visual sensor system for the width of weld pool detection is developed. By initiative arc light, the image of copper plate weld pool is taken back of the torch through the process of weakening and filtering arc light. In order to decrease the time of processing video signals, analog circuit is applied in the processing where video signals is magnified, trimmed and processed into binary on the datum of dynamic average value, therefore the waveform of video signals of weld pool is obtained. The method that is used for detecting the width of weld pool is established. Results show that the vision sensing method for real-time detecting weld pool width to copper-clad aluminum wire TIG welding is feasible. The response cycle of this system is no more than 50ms, and the testing precision is less than0.1mm.

  17. Numerical Simulation of Electromagnetic Force in Double-Sided Arc Welding Process

    Institute of Scientific and Technical Information of China (English)

    Hongming GAO; Lin WU; Honggang DONG

    2003-01-01

    Up till now, most of the researchers believe that there are four kinds of forces in the weld pool convection, they aresurface tension, electromagnetic force, buoyancy and gas shear stress. So electromagnetic force is very important,especially when large c

  18. New technology for production of granular adding material with nanomodifying additives for steel arc welding

    Directory of Open Access Journals (Sweden)

    BOLDYREV Alexander Mikhaylovich

    2016-12-01

    Full Text Available The chemical analysis of metal seam showed that introduction of titanium dioxide with MCA intensifies transition of Al2O3 from slag into metal pool and provides double concentration of titanium in the seam compared to the one which appears in the interaction of bathtub with melted flux AH-47 without TiO2 additives. The presence of oxides of titanium and aluminium of endogenous origin in the melt leads to formation of refractory particles with the center of TiO2 and Al2O3 in it. These particles are the centers of crystallization in the tail part of the molten pool and they remain in seam metal in the form of evenly distributed fine nonmetallic inclusions, which have crystallographic affinity with a matrix (α-iron. That provides the fine-grained seam structure with the raised and stable strength characteristics. This article compares the existing and developed technologies for production of MCA. The granulometric analysis of the powder TiO2 has demonstrated that when MCA is processed in the planetary mill, particles of titanium dioxide are crushed to a nanodimensional order. It is shown that the preparation of MCA in high-energy planetary mill (due to double increase of durability in coupling of the modifier with granulate provides its stable structure, increases the cold resistance (20–25% and stability of strength characteristics along the length of welded seam. Metalgraphic researches determined that the fine-grained structure which linear size of grain is twice smaller than the one obtained in the old technology welding is formed in a seam. However the direct introduction of nanomodifiers in a molten pool through the flux or an electrode wire is not efficient because of their deactivation and high temperature in welding zone. Therefore it was offered to use modifiers in the mix with the cooling macroparticles in case of automatic welding of a bridge metalware under flux using metalchemical additive (MCA. The MCA consists of a chopped

  19. 螺旋埋弧焊管焊接过程的三维数值模拟%Three-dimensional Numerical Simulation of Spiral Welded Pipe Submerged-arc Welding

    Institute of Scientific and Technical Information of China (English)

    晁利宁; 毕宗岳; 鲜林云; 余晗; 张晓峰; 张国超; 李鸿斌; 汪海涛; 马璇

    2014-01-01

    By using large-scale general finite element analysis software ABAQUS, the finite element calculation model of spiral welded pipe two-wire submerged arc welding temperature field was built. The inside and outside welding process of spiral welded pipe two-wire submerged arc welding was simulated based on welding subroutine DFLUX which was compiled by FORTRAN language, combined with the element of birth and death technology in three-dimensional finite element method. It also realized finite element calculation under moving heat source load, and obtained temperature fields distribution in welding process, after cooling down, and in the full pipe body. The results indicated that during welding process, the temperature gradient near weld is large;it is tend to smooth transition far away from the weld. With welding heat source moving, the temperature center also move, the highest temperature can reach the melting point of base metal. Through the experiment, it is consistent with simulation results.%利用大型通用有限元分析软件ABAQUS,建立了螺旋焊管双丝埋弧焊温度场的有限元计算模型。通过ABAQUS软件的FORTRAN语言编写焊接子程序DFLUX,结合“生死”单元技术,模拟了螺旋焊管双丝埋弧焊的内外焊接过程,实现在移动热源载荷下的有限元计算,获得了焊接过程和冷却后的温度场分布,以及在整个管体上的分布情况。结果表明,在焊接过程中焊缝附近温度梯度很大,在远离焊缝的地方温度梯度渐渐趋于平缓;随着热源的移动,温度中心也随之移动,最高温度可达母材的熔点。通过试验验证,与仿真结果比较吻合。

  20. 激光-电弧复合焊接中激光脉冲对电弧正-负半波作用%Effect of Laser Pulse on Positive/negative Waveform of Arc Discharge during Laser-arc Welding

    Institute of Scientific and Technical Information of China (English)

    赵建智; 陈明华; 赵作福; 辛立军

    2016-01-01

    Coupling effect between laser and arc plasma was studied when laser acting at the positive and negative wave-form of the arc discharge during laser-arc hybrid welding of magnesium alloy. By the methods of direct observation, high speed imaging and spectral analysis, the surface status of weld seams after welding, the welding penetration depths, the plasma behav-iors and the spectral characteristics of welding plasma were investigated gradually. Results show that compared with the situa-tion of laser pulse acting at the negative waveform the arc plasma discharge, better weld seam formation can be achieved when laser pulse acts at the positive waveform of the arc discharge. At the same time, the radiation intensity of Mg atoms in arc plasma greatly increases, and however, the welding penetration depth is much weaker. After analysis, it is found that when laser pulse acting at the negative waveform the arc plasma discharge, the position of arc plasma discharge on workpiece can be restrained by the laser acting point, which improves the energy density of the welding arc.%本论文研究了激光-电弧复合热源焊接镁合金过程中激光脉冲作用于交流电弧放电的正、负半波时激光与电弧的耦合作用。本文采用直接观察焊缝表面状态、高速摄像和光谱分析相结合的方式,研究了激光脉冲分别作用于电弧正、负半波时焊缝的成型特点、熔化深度、等离子体行为以及光辐射特性。结果表明,激光脉冲作用于电弧放电正、负半波时,均能实现连续焊接,电弧体积均发生膨胀。相比于激光脉冲作用于电弧放电负半波,激光脉冲作用于正半波时的焊缝成型较好,电弧等离子体中镁原子辐射强度的增加程度较大,但焊接熔深较小。通过分析,发现激光脉冲作用于电弧放电负半波可以固定电弧在板材的放电位置,提高电弧的能量密度。

  1. 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.

  2. 手工电弧焊过程危害及防护研究∗%Study on Harm and Protection of Manual Arc Welding Process

    Institute of Scientific and Technical Information of China (English)

    李学凌

    2016-01-01

    The arc welding is a common metal thermal processing technology, because its operation is simple and flexible, it is widely used in various machinery manufacturing fields, and it plays an important role. Its working principle is to make the metal junction surface melt into the plastic state with the use of heat or pressure, thus to achieve the purpose of permanent firmly adhered. While in the process of manual electric arc welding, there are many contact opportunities for occupational haz-ard factors, such as smoke, gas, noise, and arc radiation, they all would harm the health of operators. Therefore, the working principle of manual electric arc welding will be briefly introduced in this paper, and based on the damage in the process of manual arc welding, the corresponding protective measures will be proposed.%电弧焊是常见的金属热加工的工艺,因其操作简单灵活,因而被广泛应用于机械制造的各个领域,发挥了重要的作用。其工作原理是利用加热或者加压来使金属连接面融化成为塑性状态,从而达到永久牢固粘接的目的。而在手工电弧焊的过程中接触职业病危害因素的机会很多,烟尘、气体、噪声、弧光辐射都会对操作人员的健康带来危害。简要介绍手工电弧焊的工作原理,并基于手工电弧焊接过程中的危害提出相应的防护措施。

  3. Effect of Some Overlay Welding Regime With Longitudinal Magnetic Field on Hardness, Phase Composition And Welded Layer Wear By Arc Method With Flux Metal Wire

    Science.gov (United States)

    Nosov, D. G.; Peremitko, V. V.; Barashkin, M. H.

    2016-08-01

    The paper defines the range of overlay welding current, frequencies and induction of a longitudinal magnetic field that enhance the wear resistance of welded layer additing the flux. The conditions of their mutual influence on the process of structure formation are stated as well as the mathematical models linking the overlay welding current, frequency and induction of a longitudinal magnetic field with hardness, wear resistance and phase composition of the welded layer, the use of which will allow to determine the welding modes to provide the necessary properties of the weld metal.

  4. 便携式免轨细丝埋弧焊接技术研究%Research on Portable Free Rail Filaments Submerged Arc Welding Technology

    Institute of Scientific and Technical Information of China (English)

    任旭晖

    2015-01-01

    为了解决钢箱梁桥面板加劲肋由于采用CO2 气体保护焊加工而导致的焊丝熔敷率较低、焊缝成型不好、焊接飞溅大、焊接烟尘污染严重及焊后打磨处理量大等问题,并提高焊接作业效率,优化焊缝成型质量,减小变形矫正量,对综合埋弧焊和气体保护焊在应用技术上的优点进行了对比,分析了通过自制曲面反变形胎具,改制设备自动化焊接系统,使用焊剂充当保护焊缝介质来实现板单元件加劲肋的自动焊接,进行了类似结构件加工制作,取得了良好效果.%In order to solve the problems because of using CO2 gas shielded welding processing causes which welding wire deposition rate of steel box girder deck stiffening rib is lower, the weld forming is not good, welding spat-ter is large, welding smoke and dust pollution is serious, after welding polishing handling capacity is large and other, and improves the welding efficiency, optimizes the weld forming quality, reduces deformation correction amount.The advantages of comprehensive submerged arc welding and gas shielded welding in the application technology are com-pared.Through the self-made curved surface anti deformation mould, remanufactured equipment automatic welding system, used flux serve as protecting welding line medium for achieving automatic welding of the plate element stiffe-ning rib are analyzed.The similar structure processing and making are carried out.The good results are achieved.

  5. 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…

  6. Spectrum of MIG arc at different welding parameters%不同参数下MIG焊电弧光谱波动特点

    Institute of Scientific and Technical Information of China (English)

    李志勇; 张文朝; 李岩; 丁京滨

    2013-01-01

    The droplet transfer mode and arc length variation are the significant factors affecting the radiation intensity of arc plasma for MIG welding. It is critical to understand the regularity of the radiation fluctuation in application in industry control of the welding process. Therefore, the spectrum of MIG arc radiation was collected with a spectrometer based system. The spec-trums of welding processes at different welding parameters were analyzed to study the regularity of the radiation variation. Based on the arc physics, the spectral information combining with the droplet transfer mode was used to get a better understanding of the arc radiation. The results show that the arc spectrum with its distinct distribution is different at different welding parameters. The MIG arc emits wavy radiation due to droplet transfer. The spectral signals in different spectrum bands, such as ultraviolet, visible and near infrared band, have totally different variation characteristics during different instance of the droplet transfer.%熔化极惰性气体保护焊(MIG)过程中,熔滴过渡、弧长波动等会引起辐射的剧烈变化,其变化规律对于焊接质量检测具有重要意义.文中通过采集不同参数下的MIG焊电弧光谱分布,研究其在焊接过程中的变化规律;并结合该参数下熔滴过渡特征,基于电弧物理理论,对典型参数下光谱波动的规律进行物理解释.结果表明,不同参数下电弧光谱的分布和变化规律不同,具有各自的光谱分布特征;在MIG焊接过程中,由于熔滴过渡会造成光谱信息的规律波动,但在过渡的不同时间段,光谱信号在不同谱段(紫外区、可见光区、近红外区)的变化规律存在较大差异.

  7. Gas Metal Arc Weld (GMAW) Qualification of 7020-T651 Aluminum

    Science.gov (United States)

    2015-11-01

    5087 and 5556A filler metal alloys have more titanium (Ti) than typically used and necessary in ingot casting of structural alloys. The Ti serves...nucleation of solid from liquid weld metal , to refine the grain size, and modify grain structure to a more equiaxed shape. Table 2 reveals the plate...5 Table 4 details the certified mechanical properties measured in tension of the base metal 7020-T651 25.04- and 39.94-mm-thick plates. The strength

  8. 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

  9. Effect of Continuous and Pulsed Current Gas Tungsten Arc Welding on Dissimilar Weldments Between Hastelloy C-276/AISI 321 Austenitic Stainless Steel

    Science.gov (United States)

    Sharma, Sumitra; Taiwade, Ravindra V.; Vashishtha, Himanshu

    2017-02-01

    In the present investigation, an attempt has been made to join Hastelloy C-276 nickel-based superalloy and AISI 321 austenitic stainless steel using ERNiCrMo-4 filler. The joints were fabricated by continuous and pulsed current gas tungsten arc welding processes. Experimental studies to ascertain the structure-property co-relationship with or without pulsed current mode were carried out using an optical microscope and scanning electron microscope. Further, the energy-dispersive spectroscope was used to evaluate the extent of microsegregation. The microstructure of fusion zone was obtained as finer cellular dendritic structure for pulsed current mode, whereas columnar structure was formed with small amount of cellular structure for continuous current mode. The scanning electron microscope examination witnessed the existence of migrated grain boundaries at the weld interfaces. Moreover, the presence of secondary phases such as P and μ was observed in continuous current weld joints, whereas they were absent in pulsed current weld joints, which needs to be further characterized. Moreover, pulsed current joints resulted in narrower weld bead, refined morphology, reduced elemental segregation and improved strength of the welded joints. The outcomes of the present investigation would help in obtaining good quality dissimilar joints for industrial applications and AISI 321 ASS being cheaper consequently led to cost-effective design also.

  10. Numerical modeling of two-dimensional heat-transfer and temperature-based calibration using simulated annealing optimization method: Application to gas metal arc welding

    Directory of Open Access Journals (Sweden)

    Bjelić Mišo B.

    2016-01-01

    Full Text Available Simulation models of welding processes allow us to predict influence of welding parameters on the temperature field during welding and by means of temperature field and the influence to the weld geometry and microstructure. This article presents a numerical, finite-difference based model of heat transfer during welding of thin sheets. Unfortunately, accuracy of the model depends on many parameters, which cannot be accurately prescribed. In order to solve this problem, we have used simulated annealing optimization method in combination with presented numerical model. This way, we were able to determine uncertain values of heat source parameters, arc efficiency, emissivity and enhanced conductivity. The calibration procedure was made using thermocouple measurements of temperatures during welding for P355GH steel. The obtained results were used as input for simulation run. The results of simulation showed that represented calibration procedure could significantly improve reliability of heat transfer model. [National CEEPUS Office of Czech Republic (project CIII-HR-0108-07-1314 and to the Ministry of Education and Science of the Republic of Serbia (project TR37020

  11. Effect of Continuous and Pulsed Current Gas Tungsten Arc Welding on Dissimilar Weldments Between Hastelloy C-276/AISI 321 Austenitic Stainless Steel

    Science.gov (United States)

    Sharma, Sumitra; Taiwade, Ravindra V.; Vashishtha, Himanshu

    2017-03-01

    In the present investigation, an attempt has been made to join Hastelloy C-276 nickel-based superalloy and AISI 321 austenitic stainless steel using ERNiCrMo-4 filler. The joints were fabricated by continuous and pulsed current gas tungsten arc welding processes. Experimental studies to ascertain the structure-property co-relationship with or without pulsed current mode were carried out using an optical microscope and scanning electron microscope. Further, the energy-dispersive spectroscope was used to evaluate the extent of microsegregation. The microstructure of fusion zone was obtained as finer cellular dendritic structure for pulsed current mode, whereas columnar structure was formed with small amount of cellular structure for continuous current mode. The scanning electron microscope examination witnessed the existence of migrated grain boundaries at the weld interfaces. Moreover, the presence of secondary phases such as P and μ was observed in continuous current weld joints, whereas they were absent in pulsed current weld joints, which needs to be further characterized. Moreover, pulsed current joints resulted in narrower weld bead, refined morphology, reduced elemental segregation and improved strength of the welded joints. The outcomes of the present investigation would help in obtaining good quality dissimilar joints for industrial applications and AISI 321 ASS being cheaper consequently led to cost-effective design also.

  12. 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.

  13. Improved Gas Metal Arc Welding Multi-Physics Process Model and Its Application to MIL A46100 Armor-Grade Steel Butt-welds

    Science.gov (United States)

    2014-01-01

    within the weld. Design/methodology/approach The improved GMAW process model is next applied to the case of butt-welding of MIL A46100 (a...improved GMAW process model pertaining to the spatial distribution of the material microstructure and properties within the MIL A46100 butt-weld are

  14. Welding Technology Research of TIG Arc Hot Wire to Copper and Steel%TIG电弧热丝对铜、钢堆焊的工艺研究

    Institute of Scientific and Technical Information of China (English)

    柳燕; 姜华; 韩家强; 赵广军; 王晰

    2012-01-01

    针对某产品铜带焊接工艺,提出了一种电弧热丝方式应用于TIG堆焊铜、钢工艺的研究。电弧热丝可有效预热低电阻率的焊接材料,如铜;传统的电阻热丝只能加热具有高电阻率的焊接材料,如钢。采用电弧热丝系统,热丝电流小于50A时即可有效预热焊丝,与电阻热丝电流400A相当。在相同焊接电流下,能够大大提高焊接熔敷速度;在相同送丝速度下,降低焊接电流,大大降低焊接设备功率。同时证明2种热丝加热方式对钢基体、铜合金的影响相同,特别是对堆焊层铜合金中泛铁量的影响相当。%A kind of arc hot wire method is put forward to TIG welding copper and steel technology research for copper welding process of a product.Arc hot wire can effectively preheat welding materials with low resistivity,such as copper;while the traditional resistance hot wire can heat welding materials with high resistivity only,such as steel.Using arc hot wire system,wire can be preheated effectively when hot wire current is less than 50 A which is equivalent to resistance hot wire current 400 A.Under the same welding current,the weld speed can be greatly improved;in the same wire feed speed,the welding current can be reduced,which can greatly reduce the welding equipment power.At the same time that two kinds of heating methods have the same effect on steel matrix and copper alloy,especially the effect on the extensive iron content of copper alloy in surfacing layer.

  15. Indirect Prediction of Welding Fume Diffusion inside a Room Using Computational Fluid Dynamics

    Directory of Open Access Journals (Sweden)

    Sujit Dahal

    2016-05-01

    Full Text Available Welding is an important and widely used process in the manufacturing and maintenance of various works involving metals and alloys. While welding has broad applications, the welding fume generated during the process has impacts on workers’ health, which needs to be addressed. One of the major steps that can be undertaken to take care of this issue is the use of ventilation, which requires knowledge of characteristics and dispersion of the welding fume in the workers’ breathing zone. It is difficult to assess welding fume dispersion from manual measurement due to numerous welding processes and sufficient data requirement. Numerical prediction of welding fume is dubious due to several errors. This paper considers the use of numerically predicted CO2 concentrations to indirectly predict welding fume distribution in workshops. This is based on the assumption that if the particles are sufficiently small size, they follow the diffusion pattern of gases. Experiments are carried out in a room with an opening and a welding fume generation system for measurement of CO2 and fume diffusion. The results show high possibility of predicting welding fume concentration based on Computational Fluid Dynamics (CFD simulated CO2 concentration with a correlation coefficient of 0.74.

  16. 双电弧共熔池埋弧焊数字化协同控制系统%Digital Synchronic Control System for Twin-arc Co-pool High Speed Submerged Arc Weld(SAW)

    Institute of Scientific and Technical Information of China (English)

    何宽芳; 黄石生; 李学军; 肖冬明

    2011-01-01

    A digital synchronic control system for twin-arc high-speed SAM was presented by IPC(industrial personal computer) and PLC. By adopting the way of software programming, the functions of parameters optimization settings, digital control for the timing of twin arc-starting and arc-ending were achieved, which was to achieve precise control of arc energy parameters and to guarantee stability of synchronic control among the arcs. The design of hardware and software of the digital synchronic control system was also discussed. The results of weld experiments demonstrate that the developed digital synchronic control system meets the design requirements. The process of the twin-arc high speed SAW are stable, perfect forming of weld seam, which achieves technology of twin- arc high- speed SAW.%应用工控机和PLC建立了双电弧共熔池埋弧焊数字化协同控制系统.采用软件的方式实现了双电弧埋弧焊工艺参数的优化设置、两电弧起弧和收弧的时序数字化控制,从而实现了电弧能量参数的精密控制,保证了双电弧之间的协同稳定工作.阐述了数字化协同控制系统的软硬件设计.双电弧高速埋弧焊试验结果表明,所设计的数字化协同控制系统满足设计要求,焊接过程稳定、焊缝成形美观,能实现良好的双电弧高速埋弧焊工艺.

  17. 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.

  18. A new measurement method for the dynamic resistance signal during the resistance spot welding process

    Science.gov (United States)

    Wang, Lijing; Hou, Yanyan; Zhang, Hongjie; Zhao, Jian; Xi, Tao; Qi, Xiangyang; Li, Yafeng

    2016-09-01

    To measure the dynamic resistance signal during the resistance spot welding process, some original work was carried out and a new measurement method was developed. Compared with the traditional method, using the instantaneous electrode voltage and welding current at peak current point in each half cycle, the resistance curve from the newly proposed method can provide more details of the dynamic resistance changes over time. To test the specific performance of the proposed method, a series of welding experiments were carried out and the tensile shear strengths of the weld samples were measured. Then, the measurement error of the proposed method was evaluated. Several features were extracted from the dynamic resistance curves. The correlations between the extracted features and weld strength were analyzed and the results show that these features are closely related to the weld strength and they can be used for welding quality monitoring. Moreover, the dynamic resistance curve from the newly proposed method can also be used to monitor some abnormal welding conditions.

  19. 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.

  20. Advanced arc-welding robot with laser sensor technology and its application field; Laser sensor wo mochiita yosetsu robot no seigyo gijutsu no kaihatsu to tekiyo

    Energy Technology Data Exchange (ETDEWEB)

    Kugai, K.; Izawa, A. [Daihen Corporation, Osaka (Japan); Muto, S.; Mori, T. [NTT Fanet Systems Corp., Tokyo (Japan)

    1998-05-01

    A welding robot with a laser vision sensor was developed. The sensor used in this welding robot consists of a sensor head, a sensor controller, and a profile control board. The sensor controller calculates shapes of welding lines in the reference coordinates of a robot by processing different measurements, and the control board calculates them by using two-dimensional cross section information measured by the sensor. Distance from the sensor to the measurement point is measured as a result of the spot light injected from the sensor head being diffused and reflected on groove surface, part of which is collected to form an image. In addition, cross section shape of the groove is measured by giving the mirror a reciprocal arc movement in a direction perpendicular to the groove to move the mirror over the measurements points while making measurement. Influence of the arc light can be reduced by making the laser light flash sufficiently quicker than the changing speed of flashing of the arc light, and by removing information available when the light is cancelled from information available when it is lit. Extraction of points from an image as the sensor`s technological feature is performed by using the relationship between edge points and intersecting points in partial curve approximation. 10 figs., 1 tab.

  1. Test research on cold bend of {phi}1219 mm x 22 mm X80 longitudinally submerged-arc welded line pipes

    Energy Technology Data Exchange (ETDEWEB)

    Qiang, Chi; Lingkang, Ji; Yinglai, Liu; Peng, Wang [China National Petroleum Corporation (CNPC), Xi' an (China). Tubular Goods Research Center

    2009-07-01

    The tests of cold bend of {phi}1219 mm x 22 mm X80 longitudinally submerged-arc welded line pipes were done to research the effects of cold bend processes on the configuration and property of X80 steel pipe in this paper. In the filed bend tests, the six kinds radius of curvature consist of 18D, 20D, 24D, 28D, 35D and 47D (D is the diameter of steel pipe) were adopted. The results of welding seam non-destructive and macrograph examination show that the effect of bending process on the quality of welding seam is not obvious. The appearance inspections show that the serious distortions occur on the bend pipes of 18D and 20D radius of curvature. The mechanical property tests results indicate that the change of the transverse tensile property, toughness and hardness of cold bend pipes manufactured by various radius of curvature compare with the mother pipe are smaller. The change of longitudinal tensile property is bigger. Compared with the mother pipe, the yield strength and yield ratio in inner arc of bend pipe decrease, but those in outer arc of bend pipe increase. The longitudinal tensile curves in different sampling locations of bend pipe exhibit a rather large difference. (author)

  2. 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.

  3. 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

  4. 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.

  5. 弧焊机器人工作站协同作业研究%Research on Collaboration of Arc-welding Robot Workstation

    Institute of Scientific and Technical Information of China (English)

    陈美宏; 焦恩璋

    2011-01-01

    Taking coupling planning, the collaborative paths of are-welding robot/positioner workstation and multi-robot welding workstation were planned. By use of self-developed collaborative path planners, the drive functions for simulation models of arc-welding robot workstations were built. Collaborative simulations of saddle-shaped weld seam and twist weld seam were accomplished. The simu lation results show the method of collaborative path planning is correct and feasible.%采用耦合规划方法,对弧焊机器人/变位机工作站和多机器人焊接工作站的协同作业路径进行规划.利用自主开发的协调路径规划器,构建弧焊机器人工作站仿真模型的驱动函数,完成了马鞍型焊缝和螺旋线焊缝的协同作业仿真实验,验证了协同作业路径规划方法的正确性和可行性.

  6. 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.

  7. Tensile and Impact Properties of Shielded Metal Arc Welded AISI 409M Ferritic Stainless Steel Joints

    Institute of Scientific and Technical Information of China (English)

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

    2009-01-01

    The present study is concerned with the effect of filler metals such as austenitic stainless steel, ferritic stainless steel and duplex stainless steel on tensile and impact properties of the ferritic stainless steel conforming to AISI 409M grade. Rolled plates of 4 mm thickness were used as the base material for preparing single pass butt welded joints. Tensile and impact properties, microhardness, microstructure and fracture surface morphology of the joints fabricated by austenitic stainless steel, ferritic stainless steel and duplex stainless steel filler metals were evaluated and the results were reported. From this investigation, it is found that the joints fabricated by duplex stainless steel filler metal showed higher tensile strength and hardness compared to the joints fabricated by austenitic and ferritic stainless steel filler metals. Joints fabricated by austenitic stainless steel filler metal exhibited higher ductility and impact toughness compared with the joints fabricated by ferritic stainless steel and duplex stainless steel filler metals.

  8. Evaluation of erythemal UV effective irradiance from UV lamp exposure and the application in shield metal arc welding processing.

    Science.gov (United States)

    Chang, Cheng-Ping; Liu, Hung-Hsin; Peng, Chiung-Yu; Fang, Hsin-Yu; Tsao, Ta-Ho; Lan, Cheng-Hang

    2008-04-01

    Ultraviolet radiation (UVR) exposure is known to cause potential effects such as erythema in skin. For UV-induced erythema (sunburn), the action spectrum from the Commission Internationale de l'Eclairage, International Commission on Illumination (CIE) was adopted. Erythemal UV effects from UVR lamp exposure were investigated with commercial spectroradiometry devices in this research. Three kinds of portable UV germicidal lamps with broadband UVA (BB UVA, 350-400 nm), broadband UVB (BB UVB, 280-350 nm), and narrowband UVC (NB UVC, 254 nm) wavelengths served as the UVR emission sources. An action spectrum expresses the effectiveness of radiation for assessing the hazard of UVR in the erythemal action spectrum from 250-400 nm. The UV Index (UVI) is an irradiance scale computed by multiplying the CIE erythemal irradiance integral in milliwatts per square meter by 0.04 m mW. A comprehensive approach to detecting erythemal UVR magnitude was developed to monitor the effective exposure from UV lamps. The erythemal UVR measurement was established and the exposure assessment was applied to monitor erythemal UVR magnitude from shield metal arc welding (SMAW) processing. From this study, the erythemal UVR exposures were assessed and evaluated with environmental solar simulation of the UVI exposure.

  9. Influence of the gas shielding method upon the properties of the weld joints

    Science.gov (United States)

    Chinakhov, D. A.; Sapozhkov, A. S.

    2016-11-01

    The authors consider the influence of the gas shielding method under consumable electrode welding and double-jet gas shielding together with its influence upon the processes in the arc zone and the properties of weld joints from high-strength alloyed 30HGSA steel. The authors provide the results of recent experimental research on weld joints properties improvement through changing the gas dynamics of the active shielding gas. It was established that the jet of active shielding gas has a considerable gas-dynamic influence upon weld joints formation, chemical composition, structure and properties of the weld joints from high-strength alloyed steels.

  10. 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.

  11. Predictive Modeling of Mechanical Properties of Welded Joints Based on Dynamic Fuzzy RBF Neural Network

    Directory of Open Access Journals (Sweden)

    ZHANG Yongzhi

    2016-10-01

    Full Text Available A dynamic fuzzy RBF neural network model was built to predict the mechanical properties of welded joints, and the purpose of the model was to overcome the shortcomings of static neural networks including structural identification, dynamic sample training and learning algorithm. The structure and parameters of the model are no longer head of default, dynamic adaptive adjustment in the training, suitable for dynamic sample data for learning, learning algorithm introduces hierarchical learning and fuzzy rule pruning strategy, to accelerate the training speed of model and make the model more compact. Simulation of the model was carried out by using three kinds of thickness and different process TC4 titanium alloy TIG welding test data. The results show that the model has higher prediction accuracy, which is suitable for predicting the mechanical properties of welded joints, and has opened up a new way for the on-line control of the welding process.

  12. 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.

  13. Dynamics of diachronous back-arc extension: insights from 3D thermo-mechanical analogue experiments

    Science.gov (United States)

    Boutelier, D. A.; Cruden, A. R.

    2013-12-01

    Subduction of an old, dense oceanic lithosphere can lead to rifting and extension of the magmatic arc. Such subduction systems are inherently three-dimensional with significant along-strike variations in the timing and style of deformation and magmatism. Geodynamic models used to explain such variations and associated trench curvature generally ignore the role of the overriding plate and its deformation. 3D thermo-mechanical analogue experiments are used to investigate the kinematics and dynamics of diachronous arc rifting and back-arc basin opening. In the models, horizontal tension increases in the upper plate until the magmatic arc lithosphere fails and back-arc opening occurs via slab rollback. This result corresponds well to previous 2D models of arc rifting and subsequent back-arc opening via trench rollback and the mechanics of retreating slabs in fluid dynamic experiments. However, in our experiments arc failure occurs diachronously, initiating near the model edge due to locally higher temperatures and lower strength and then propagating along strike, producing an arcuate plate boundary. The experiments demonstrate that trench rollback rate is limited by the propagation rate of arc failure. Conversely, slab rollback generates additional horizontal tension in the adjacent magmatic arc lithosphere, which drives along-strike propagation of arc failure. Feedback between the rates of trench rollback and arc failure propagation dictates the geometry of the back-arc basin in plan-view. The shape of the back-arc basin obtained in models fits remarkably well with that of the Mariana basin in the western Pacific. Experiments where the strength of the magmatic arc, or forearc varies along strike or where the negative buoyancy of the subducting plate varies along strike explore further the role of the slab edge and the trench-parallel tensile strength of the retreating forearc block.

  14. A Generalized Rough Set Modeling Method for Welding Process

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Modeling is essential, significant and difficult for the quality and shaping control of arc welding process. A generalized rough set based modeling method was brought forward and a dynamic predictive model for pulsed gas tungsten arc welding (GTAW) was obtained by this modeling method. The results show that this modeling method can well acquire knowledge in welding and satisfy the real life application. In addition, the results of comparison between classic rough set model and back-propagation neural network model respectively are also satisfying.

  15. 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.

  16. 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

  17. Application of Submerged Arc Welding Without Back Chipping in Steel Structure Industry%埋弧焊免清根技术在钢结构行业的应用∗

    Institute of Scientific and Technical Information of China (English)

    2015-01-01

    在建筑钢结构制作行业,埋弧焊焊接工艺应用非常普遍。埋弧焊以生产效率高,焊接质量稳定,劳动条件好等优势在钢结构加工行业占有一席之地。埋弧焊免清根技术的应用,对钢结构焊接中的成本控制有着举足轻重的作用。介绍了埋弧焊免清根技术的优点及施工难点,并进行试件试验分析了其施工参数及技术要点。%In the structural steelwork fabrication industry, submerged arc welding is widely used. The submerged arc welding has high production efficiency with stable welding quality and good working condition, thus making it take a place in this industry. With the application of submerged arc welding without back gouging technology, it will play a significant role in the cost control of structural steelwork welding. This paper introduces the advantages and difficulties. Then through components test the construction parameters and technical keys of submerged arc welding are analyzed.

  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. Research for Multiple-electrode Submerged Arc Welding Process with Low Heat Input%低热输入多丝埋弧焊工艺研究

    Institute of Scientific and Technical Information of China (English)

    孙宏; 田鹏; 宗秋丽; 刘振伟; 纪鹏蕊

    2016-01-01

    研究开发出了一种新型高强度、 大壁厚UOE钢管埋弧焊工艺.该工艺采用小直径焊丝作为多丝焊的前丝(第1丝),将焊接热输入降低25%,细化了热影响区原始奥氏体的晶粒尺寸,从而提高了API X65钢级大壁厚管线钢管焊缝热影响区的韧性.试验结果表明,该工艺可以实现焊接接头完全焊透,同时具有充足的熔敷金属,达到了与传统方法相同的熔深.通过超声波和射线检测,焊缝均未发现未焊透、 夹渣等焊接缺陷,焊缝形貌良好.%It developed a new submerged arc welding (SAW) process for high-strength and heavy wall thickness UOE pipes. A new SAW process which can reduce heat input of 25% due to its high deposition rate and deep penetration is performed with multiple electrode SAW using small diameter welding wire on lead electrode. The results show that improvement of heat affected zone(HAZ) toughness in seam welding on API X65 heavy wall linepipe and refinement of prior austenite grain size in HAZ was achieved in order to reduce its heat input by the new process. This process can achieve full penetration of welded joint, has plenty of deposited metal, which can obtain the same penetration as the traditional method. By ultrasonic and X-ray testing, not found defects in weld such as lack of penetration, slag and so on, the weld appearance is good.

  20. 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)

  1. 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.

  2. Control of exposure to hexavalent chromium and ozone in gas metal arc welding of stainless steels by use of a secondary shield gas.

    Science.gov (United States)

    Dennis, John H; French, Michael J; Hewitt, Peter J; Mortazavi, Seyed B; Redding, Christopher A J

    2002-01-01

    Previous work has demonstrated that the shield gas composition in gas metal arc welding can have a considerable effect on hexavalent chromium [Cr(VI)] concentration in the fume and on ozone concentrations near the arc. Normally a single shield gas is used. This paper describes a double shroud torch that allows used of concentric shield gases of different compositions. A solid stainless steel wire was used for welding. The double shroud torch used secondary shield gases containing small amounts of the reducing agents NO and C2H4. The Cr(VI) concentration in the fume and ozone concentration at a fixed point relative to the arc were measured and compared with results when using a single shield gas. Use of the reducing agents in secondary shielding using the double shroud torch was found to offer advantages for ozone concentration reduction compared with use in a conventional torch, but this was not found to be an advantage for reducing Cr(VI) concentrations.

  3. 保护气体对激光-电弧复合焊接的影响%Effects of Shielding Gas in Laser-Arc Hybrid Welding

    Institute of Scientific and Technical Information of China (English)

    曾晓雁; 高明; 严军

    2011-01-01

    Laser-arc hybrid welding has absorbed wide interesting in the past years due to its potential industrial applications, in which shielding gas plays an important role to achieve the effective laser-arc synergy effect and stable process. The effects of the shielding gas on the bead quality for laser-arc hybrid welding are reviewed. The mechanisms about the parameters of the shielding gas on process characteristics, bead shape and joint mechanical properties are discussed.%激光-电弧复合焊接是焊接领域的研究热点,工业应用前景广阔.保护气体是实现激光一电弧有效复合、获得最大效能的关键参数.结合国内外研究及作者的研究工作,综述了保护气体成分、配比、流量等参数对激光一电弧复合焊接工艺特性,焊缝形貌特征和接头力学性能的影响及研究现状.

  4. Optimization of Fusion Zone Grain Size, Hardness, and Ultimate Tensile Strength of Pulsed Current Microplasma Arc Welded AISI 304L Sheets Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Siva Prasad Kondapalli

    2014-01-01

    Full Text Available Austenitic stainless steel sheets have gathered wide acceptance in the fabrication of components, which require high temperature resistance and corrosion resistance, such as metal bellows used in expansion joints in aircraft, aerospace, and petroleum industry. In case of single pass welding of thinner sections of this alloy, Pulsed Current Microplasma Arc Welding (PCMPAW was found beneficial due to its advantages over the conventional continuous current process. The quality of welded joint depends on the grain size, hardness, and ultimate tensile strength, which have to be properly controlled and optimized to ensure better economy and desirable mechanical characteristics of the weld. This paper highlights the development of empirical mathematical equations using multiple regression analysis, correlating various process parameters to grain size, and ultimate tensile strength in PCMPAW of AISI 304L sheets. The experiments were conducted based on a five-factor, five-level central composite rotatable design matrix. A genetic algorithm (GA was developed to optimize the process parameters for achieving the desired grain size, hardness, and ultimate tensile strength.

  5. Mathematical modelling of convective processes in a weld pool under electric arc surfacing

    Science.gov (United States)

    Sarychev, V. D.; Granovskii, A. Yu; Nevskii, S. A.; Konovalov, S. V.

    2017-01-01

    The authors develop the mathematical model of convective processes in a molten pool under electric arc surfacing with flux-cored wire. The model is based on the ideas of how convective flows appear due to temperature gradient and action of electromagnetic forces. Influence of alloying elements in the molten metal was modeled as a non-linear dependence of surface tension upon temperature. Surface tension and its temperature coefficient were calculated according to the electron density functional method with consideration to asymmetric electron distribution at the interface “molten metal / shielding gas”. Simultaneous solution of Navier-Stokes and Maxwell equations according to finite elements method with consideration to the moving heat source at the interface showed that there is a multi-vortex structure in the molten metal. This structure gives rise to a downward heat flux which, at the stage of heating, moves from the centre of the pool and stirs it full width. At the cooling stage this flux moves towards the centre of the pool and a single vortex is formed near the symmetry centre. This flux penetration is ∼ 10 mm. Formation of the downward heat flux is determined by sign reversal of the temperature coefficient of surface tension due to the presence of alloying elements.

  6. The Comparative Effect of Sugarcane Juice on the Abrasion-Corrosion Behavior of Fe-Cr-B Electric Arc Sprayed and Fe-Cr-C Weld Coatings

    Science.gov (United States)

    Buchanan, Vernon E.

    2012-02-01

    Abrasion-corrosion tests were conducted on two commonly Fe-Cr-C shielded metal arc welding (SMAW) hardfacings used in the sugar industry and an arc sprayed Fe-Cr-based coating. The tests were performed on a modified block-on-ring tester with the coatings sliding against compressed sugarcane fiber in the presence of abrasive slurry. The findings showed that, in the presence of sugarcane juice and sand slurry, the SMAW coatings had similar wear performance while the abrasive wear of the arc-sprayed coating was superior to the SMAW coatings. In the presence of a neutral solution, the material loss from the arc-sprayed coating was similar to that obtained in the sugarcane juice while the SMAW coatings showed a marked decrease; this demonstrated that the arc-sprayed coating was more desirable in an abrasive-corrosion environment. The study also showed that the resistance to material does not follow the expected trend, in which wear resistance increases with increasing hardness.

  7. 高性能焊接电弧的研究与应用%Research and development of high performance welding arc

    Institute of Scientific and Technical Information of China (English)

    宋永伦

    2013-01-01

    A proposal for establish high energy density arc in hyper-normal mode under the Gas Tungsten Arc Welding condition is put forward.The main mechanisms for enhancing energy density are according to the effects of self-magnetic convergence and thermal-ionization.The physical structure is based on multi-electrode for arc aggregation.It would enhance argon ionization degree and higher arc energy density under circumstances in the proposal.Furthermore,the efficacy of the arc coupling with high frequency pulsed current is investigated to obtain better joint property.%在原钨极惰性气体保护焊(GTAW)条件下,提出了与高频能量耦合的脉冲电弧效应及其焊接工艺特性;提出以多电极并联聚束为特征、能增强电弧“自磁收缩”和气体“热电离”效应为主导机理的焊接电弧结构,实现电弧能量密度和工艺性能的提高;本研究为推动新一代焊接电弧具有“控形”与“控性”两方面的功能提供了思路.

  8. Optimization Of Pulsed Current Parameters To Minimize Pitting Corrosion İn Pulsed Current Micro Plasma Arc Welded Aısı 304l Sheets Using Genetic Algorithm

    Directory of Open Access Journals (Sweden)

    Kondapalli Siva Prasad

    2013-06-01

    Full Text Available Austenitic stainless steel sheets have gathered wide acceptance in the fabrication of components, which require high temperature resistance and corrosion resistance, such as metal bellows used in expansion joints in aircraft, aerospace and petroleum industry. In case of single pass welding of thinner sections of this alloy, Pulsed Current Micro Plasma Arc Welding (PCMPAW was found beneficial due to its advantages over the conventional continuous current process. This paper highlights the development of empirical mathematical equations using multiple regression analysis, correlating various process parameters to pitting corrosion rates in PCMPAW of AISI 304L sheets in 1 Normal HCl. The experiments were conducted based on a five factor, five level central composite rotatable design matrix. A Genetic Algorithm (GA was developed to optimize the process parameters for minimizing the pitting corrosion rates.

  9. 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.

  10. 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.

  11. 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.

  12. 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.

  13. The Influence of Weld Metal Alloying Additions to Extend the Heat Input Range for the Submerged Arc Welding of High Strength Steels

    Science.gov (United States)

    1993-12-16

    in the weld metal is planned to be two fold. First, the for- mation of niobium carbide precipitates is expected to reduce the amount of free carbon...and niobium carbide ) in the matrix and more uniform mechanical proper- ties are anticipated. Second, The combination of two kinds of precipitates...produced by a consumables manufacturer) will be used to generate welds for mechanical and impact toughness data. Additionally, the e-copper and niobium

  14. Investigation of laser tissue welding dynamics via experiment and modeling.

    Science.gov (United States)

    Small, W; Maitland, D J; Heredia, N J; Eder, D C; Celliers, P M; Da Silva, L B; London, R A; Matthews, D L

    1997-02-01

    An in vitro study of laser tissue welding mediated with a dye-enhanced protein solder was performed. Freshly harvested sections of porcine aorta were used for the experiments. Arteriotomies approximately 4 mm in length were treated using an 805 nm continuous-wave diode laser coupled to a 1-mm diameter fiber. Temperature histories of the surface of the weld site were obtained using a fiberoptic-based infrared thermometer. The experimental effort was complemented by the LATIS (LAser-TISsue) computer code, which numerically simulates the exposure of tissue to near-infrared radiation using coupled Monte Carlo, thermal transport, and mass transport models. Comparison of the experimental and simulated thermal results shows that the inclusion of water transport and evaporative losses in the model is necessary to determine the thermal distributions and hydration state in the tissue. The hydration state of the weld site was correlated with the acute weld strength.

  15. 弧焊机器人焊缝跟踪神经网络控制器%Application of Neural Network Controller in the Seam Tracking of Arc-Welding Robot

    Institute of Scientific and Technical Information of China (English)

    高向东; 黄石生; 毛利彰; 山本元司

    1999-01-01

    介绍一种能提高弧焊机器人焊缝跟踪精度的神经网络控制器.通过神经网络的补偿作用,弥补了由于无法知道机器人精确模型所造成的控制上的误差.不同于机器人控制中传统的神经网络控制器,本文提出并应用了基于笛卡尔空间轨迹控制的机器人焊缝跟踪神经网络,大大简化了控制算法.计算机模拟及实验结果表明,该控制器非常适用于机器人的实际焊接,对于现有的机器人,无须改变其控制器内部结构,即可应用该技术.与常用的机器人关节力矩控制法相比,有效地提高了跟踪精度并具有较强的鲁棒性.%A neural network(NN) controller which improves the accuracy of seam tracking of an arc-welding robot is presented in this paper. The improvement of tracking accuracy can be achieved by applying the NN controller for compensating for model uncertainties of robot manipulator. Unlike the traditional NN compensation of model uncertainties which was carried through by modifying the joint/force of the robot, the proposed NN compensation is used to modify the reference Cartesian seam trajectory, which is easily applied in practice. The required internal signal level of proposed NN for the seam modification is much smaller. Simulations and experiments have been performed on an actual arc-welding robot manipulator to test the effectiveness of NN control scheme. It has been found that NN can generate better tracking performance than the traditional computed torque(CT) control method which is based on the manipulator dynamics only. One goal of this paper is to stimulate further discussion of application of NN in the arc-welding robot control.

  16. Analysis of arc pressure and its weld quality in hybrid ultra-high frequency pulse VP-GTAW process%HPVP-GTAW电弧力及焊接质量分析

    Institute of Scientific and Technical Information of China (English)

    从保强; 齐铂金; 杨明轩; 李伟; 王乐笑; 杨舟; 李玉龙

    2013-01-01

    分别以3种不同材质铝合金平板材料为试验对象,研究分析了复合超高频脉冲方波变极性钨极氩弧焊接(HPVP-GTAW)过程中电弧力的变化及其对焊缝成形特征和接头力学性能的影响.结果表明,与常规变极性氩弧焊工艺相比,脉冲方波电流的加入使得HPVP-GTAW电弧力显著增加,同时焊缝熔透率大幅提高,接头力学性能得到明显改善和提高;保持脉冲电流幅值和占空比基本不变,在10~80 kHz范围内,脉冲电流频率对焊接过程产生了重要影响,频率为40 kHz时,HPVP-GTAW电弧力和焊缝熔透率均达到最大,分别约为常规变极性焊接电弧的1.9倍和1.7倍.%The variations of arc pressure and weld characteristics in the welding of 2219, 2A14 and 5A06 aluminum alloys were investigated based on the hybrid ultrahigh frequency pulse current variable polarity gas tungsten arc welding ( HPVP-GTAW) process. The experimental results show that compared with the conventional VP-GTAW ( variable polarity gas tungsten arc welding) process, arc pressure and weld penetration expressed by the ratio of weld depth to width are enhanced predominantly with the effect of high frequency pulse current. Mechanical properties of welded joints are improved obviously. At the given pulse current amplitude and pulse duty cycle, the welding process is influenced significantly by the pulse current frequency in the range of 10 kHz to 80 kHz. At the given pulse frequency of 40 kHz, arc pressure and weld penetration of welded joints increased by about 90% and 70% , respectively, compared with that of welded joints with no effect of pulse current.

  17. 双丝间接电弧氩气保护焊的熔滴过渡与电弧形态%Relationship between metal transfer and arc shape in twin-wire indirect arc welding

    Institute of Scientific and Technical Information of China (English)

    曹梅青; 邹增大; 曲仕尧

    2012-01-01

    用高速摄像系统及示波器对双丝间接电弧氩弧焊的熔滴过渡及电弧形态和电弧电压之间的关系进行了深入分析.结果表明,熔滴过渡和电弧电压、电弧形态的规律性变化存在密切的对应关系.熔滴形成、长大、脱离焊丝端部的规律性变化使极性斑点间距及弧柱电阻发生变化导致了电弧电压的波动,从而使电弧形态发生由暗到明、由小到大的规律性变化.随着焊接电流的增大熔滴的过渡形式发生变化,熔滴尺寸减小.不同的熔滴过渡形式其电弧电压的波动也有所不同,射流过渡电压波动较小,而短路过渡电弧电压的波动最大.%Relationship between metal transfer,arc shape and arc voltage was investigated with high speed camcorder system and digital oscillograph.Results show that metal transfer has a close relationship with arc voltage and the regular variation of arc shape.It shows that the regular changes of metal transfer make polarity spots spacing and arc beam resistance change and cause the arc voltage fluctuations,so that the arc shape changes regularly.Droplet transfer pattern changes and droplet size dereases with the increasing of welding current,different metal transfer mode has different arc voltage fluctuation,spraying transfer has lower variation of voltage but short transfer's arc voltage variation is bigger.

  18. Study of gas tungsten arc welding procedures for tantalum alloy T-111 (Ta-8 W-2Hf) plate

    Science.gov (United States)

    Gold, R. E.; Kesterson, R. L.

    1973-01-01

    Methods of eliminating or reducing underbread cracking in multipass GTA welds in thick T-111 plate were studied. Single V butt welds prepared using experimental filler metal compositions and standard weld procedures resulted in only moderate success in reducing underbread cracking. Subsequent procedural changes incorporating manual welding, slower weld speeds, and three or fewer fill passes resulted in crack-free single V welds only when the filler metal was free of hafnium. The double V joint design with successive fill passes on opposite sides of the joint produced excellent welds. The quality of each weld was determined metallographically since the cracking, when present, was very slight and undetectable using standard NDT techniques. Tensile and bend tests were performed on selected weldments. The inherent filler metal strength and the joint geometry determined the strength of the weldment. Hardness and electron beam microprobe traverses were made on selected specimens with the result that significant filler metal-base metal dilution as well as hafnium segregation was detected. A tentative explanation of T-111 plate underbread cracking is presented based on the intrinsic effects of hafnium in the weldment.

  19. 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...

  20. Microsegregation and Precipitates in Inconel 625 Arc Weld Overlay Coatings on Boiler Pipes / Mikrosegregacja I Wydzielenia W Powłokach Ze Stopu Inconel 625 Napawanych Łukowo Na Rury Kotłowe

    Directory of Open Access Journals (Sweden)

    Rozmus-Górnikowska M.

    2015-12-01

    Full Text Available The aim of this work was to investigate the microsegregation and precipitates formed due to segregation in Inconel 625 arc weld overlay coatings on boiler pipes. Examination of microsegregation and precipitates were carried out by means of a scanning electron microscope (SEM equipped with an EDS detector as well as a transmission electron microscope (TEM equipped with a HAADF (STEM and an EDS detectors. The presence of precipitations in the weld overlay was also confirmed with X-ray diffraction analysis (XRD of residue in the form of powder that remained after the electrolytic dissolution of weld overlay matrix.

  1. 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

  2. Comparison of microstructure and mechanical properties of ultra-narrow gap laser and gas-metal-arc welded S960 high strength steel

    Science.gov (United States)

    Guo, Wei; Li, Lin; Dong, Shiyun; Crowther, Dave; Thompson, Alan

    2017-04-01

    The microstructural characteristics and mechanical properties, including micro-hardness, tensile properties, three-point bending properties and Charpy impact toughness at different test temperatures of 8 mm thick S960 high strength steel plates were investigated following their joining by multi-pass ultra-narrow gap laser welding (NGLW) and gas metal arc welding (GMAW) techniques. It was found that the microstructure in the fusion zone (FZ) for the ultra-NGLW joint was predominantly martensite mixed with some tempered martensite, while the FZ for the GMAW joint was mainly consisted of ferrite with some martensite. The strength of the ultra-NGLW specimens was comparable to that of the base material (BM), with all welded specimens failed in the BM in the tensile tests. The tensile strength of the GMAW specimens was reduced approximately by 100 MPa when compared with the base material by a broad and soft heat affected zone (HAZ) with failure located in the soft HAZ. Both the ultra-NGLW and GMAW specimens performed well in three-point bending tests. The GMAW joints exhibited better impact toughness than the ultra-NGLW joints.

  3. Effect of ultrasound on plasma arc and experimental research on welding%超声对等离子电弧的影响及焊接试验研究

    Institute of Scientific and Technical Information of China (English)

    范成磊; 谢伟峰; 杨春利; 林三宝; 孙清洁; 范阳阳

    2015-01-01

    With the development of modern industry, the application of ultrasound in materials processing is getting more and more widespread and important. There are many ultrasonund-welding methods, all of those have improved welding quality and production efficiency to a certain degree, and enhance the adaptability of welding. An ultrasonic-arc technique, utilizing external ultrasonic source to regulate plasma arc (welding heat source), is described in detail in this paper. The arc test shows that the shape of the arc modulated by ultrasound is conical instead of bell-shaped, and this compression effect is very obvious. While in the welding test, with ultrasound, the size of welding droplet is smaller than that without ultrasound, and the transition frequency is significantly increased. By using this method, some of the shortcomings in ordinary arc welding can be overcomed, such as arc energy divergence, the low quality of welds and low welding efficiency.%随着现代工业生产技术的发展,超声波在材料加工领域应用越来越广泛,相继出现了多种超声波与焊接相结合的方式,在一定程度上提高了焊接质量和生产效率,增强了焊接的适应性。详细介绍了一种超声电弧技术,即利用外加超声源调控等离子电弧作为相应热源进行焊接的技术。电弧试验研究显示,受超声调制的等离子电弧呈规则的圆锥形,压缩明显,电弧中心区压力增大。在焊接试验中,发现施加超声后,焊接熔滴尺寸更小,过渡频率明显增加,焊缝的熔宽和熔深都不同程度增加。利用该方法可以克服普通电弧焊接熔深浅、电弧能量不集中、焊接效率低等缺点。

  4. Parametric Optimization Of Gas Metal Arc Welding Process By Using Grey Based Taguchi Method On Aisi 409 Ferritic Stainless Steel

    Science.gov (United States)

    Ghosh, Nabendu; Kumar, Pradip; Nandi, Goutam

    2016-10-01

    Welding input process parameters play a very significant role in determining the quality of the welded joint. Only by properly controlling every element of the process can product quality be controlled. For better quality of MIG welding of Ferritic stainless steel AISI 409, precise control of process parameters, parametric optimization of the process parameters, prediction and control of the desired responses (quality indices) etc., continued and elaborate experiments, analysis and modeling are needed. A data of knowledge - base may thus be generated which may be utilized by the practicing engineers and technicians to produce good quality weld more precisely, reliably and predictively. In the present work, X-ray radiographic test has been conducted in order to detect surface and sub-surface defects of weld specimens made of Ferritic stainless steel. The quality of the weld has been evaluated in terms of yield strength, ultimate tensile strength and percentage of elongation of the welded specimens. The observed data have been interpreted, discussed and analyzed by considering ultimate tensile strength ,yield strength and percentage elongation combined with use of Grey-Taguchi methodology.

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

    NARCIS (Netherlands)

    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

  6. Proactive Control Effect of Arc and Weld Pool Behaviors by an External Magnetic Field in High Speed GMAW%外加磁场对高速GMAW电弧和熔池行为的主动调控效应

    Institute of Scientific and Technical Information of China (English)

    王林; 武传松; 杨丰兆; 高进强

    2016-01-01

    在熔化极气体保护焊(Gas metal arc welding, GMAW)过程中,当焊接速度超过临界值后,焊缝成形变差,出现咬边和驼峰焊道,无法满足生产要求。研究证明,熔池中动量很大的后向液体流是产生驼峰焊道的主要原因。自主研发外加磁场发生装置,向熔池施加横向电磁力,对后向液体流进行主动干预,并调控熔池流态,从而抑制驼峰焊道的形成。在Q235低碳钢板上开展焊接工艺试验,获得了不同磁感应强度下的焊缝表面成形;采用高速摄像技术,拍摄焊接过程中的电弧和熔池图像,分析外加磁场对电弧形态、熔池流场和焊缝成形的影响规律,初步揭示外加磁场抑制驼峰焊道的机理。试验结果表明,外加横向磁场能明显调控熔池流态,减小后向液体流的动量,并能有效抑制驼峰焊道和咬边等缺陷,显著改善焊缝成形,提高临界焊接速度。%In high speed gas metal arc welding (GMAW) process, the weld formation quality will get worsen and weld defects like humping bead and undercutting will appear when welding speed exceeds the critical value. The previous investigations have proved that the backward flowing molten jet with high momentum in the weld pool is responsible for the formation of humping bead in high speed GMAW process. An external electromagnetic field generator is developed to conduct proactive control of the backward flowing molten jet in the weld pool, and adjust the weld pool fluid flow field, in order to suppress the occurrence tendency of the humping bead. Bead-on plate welding experiments are performed on mild steel Q235 test-pieces, and the weld bead appearance under different magnetic flux density are obtained. The high speed camera is used to capture the images of the arc and the weld pool during the welding process. The influences of the exerted magnetic flux density to the arc behavior, the fluid flow inside the weld pool, and

  7. 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.

  8. Characterization and Optimization of Ni-WC Composite Weld Matrix Deposited by Plasma-Transferred Arc Process

    Science.gov (United States)

    Tahaei, Ali; Horley, Paul; Merlin, Mattia; Torres-Torres, David; Garagnani, Gian Luca; Praga, Rolando; Vázquez, Felipe J. García; Arizmendi-Morquecho, Ana

    2017-01-01

    This work is dedicated to optimization of carbide particle system in a weld bead deposited by PTAW technique over D2 tool steel with high chromium content. The paper reports partial melting of the original carbide grains of the Ni-based filling powder, and growing of the secondary carbide phase (Cr, Ni)_3 W_3 C in the form of dendrites with wide branches that enhanced mechanical properties of the weld. The optimization of bead parameters was made with design of experiment methodology complemented by a complex sample characterization including SEM, EDXS, XRD, and nanoindentation measurements. It was shown that the preheat of the substrate to a moderate temperature 523 K (250° C) establishes linear pattern of metal flow in the weld pool, resulting in the most homogeneous distribution of the primary carbides in the microstructure of weld bead.

  9. Characterization and Optimization of Ni-WC Composite Weld Matrix Deposited by Plasma-Transferred Arc Process

    Science.gov (United States)

    Tahaei, Ali; Horley, Paul; Merlin, Mattia; Torres-Torres, David; Garagnani, Gian Luca; Praga, Rolando; Vázquez, Felipe J. García; Arizmendi-Morquecho, Ana

    2017-03-01

    This work is dedicated to optimization of carbide particle system in a weld bead deposited by PTAW technique over D2 tool steel with high chromium content. The paper reports partial melting of the original carbide grains of the Ni-based filling powder, and growing of the secondary carbide phase (Cr, Ni)_3W_3C in the form of dendrites with wide branches that enhanced mechanical properties of the weld. The optimization of bead parameters was made with design of experiment methodology complemented by a complex sample characterization including SEM, EDXS, XRD, and nanoindentation measurements. It was shown that the preheat of the substrate to a moderate temperature 523 K (250° C) establishes linear pattern of metal flow in the weld pool, resulting in the most homogeneous distribution of the primary carbides in the microstructure of weld bead.

  10. 焊剂带约束电弧超窄间隙焊接工艺实验%Processing Experiment of Ultra-narrow Gap Welding with Constrained Arc by Flux Strips

    Institute of Scientific and Technical Information of China (English)

    朱亮; 冯志鹏; 李宗志

    2011-01-01

    The behaviors of arc constrained by flux strips were basically understood, which has obvious advantages for ultra-narrow gap welding. With 4 mm wide square groove, 30 mm thick steel plate, a series of multi-layer and single-pass ultra-narrow gap welding experiments were conducted. The welded joint was completed by root welding, filling welding and cover welding, their welding parameters were obtained from the experimental analysis. The results show that the energy input of this processing is low (about 0.6 kJ/mm). The width of heat-affected zone of welded joint was narrow (about 1.3 mm). Using H08Mn2Si wire of carbon-dioxide arc welding, the hardness in weld bead can increase about 60% by adopting ultra-narrow gap welding compared with that of adopting carbon-dioxide arc welding.%焊剂带约束电弧的行为已有基本的认识,用于超窄间隙焊接有明显的优势.在间隙宽度为4mm、钢板厚度为30mm的I形坡口中,进行多层单道焊剂带约束电弧超窄间隙焊接试验.整个焊接接头要通过根焊、填充焊和盖面焊来完成,通过试验分析得到各焊道所对应的焊接工艺参数.这种超窄间隙焊接方法线能量低,约为0.6kJ/mm;所得到焊接接头的热影响区宽度窄,约为1.3 mm;采用常规的CO2气保焊焊丝H08Mn2Si,超窄间隙焊缝硬度比CO2气保焊焊缝硬度提高60%.

  11. 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.

  12. Effects of weld damage on the dynamics of energy absorbing lanyards.

    Science.gov (United States)

    Katona, David N; Bennett, Charlie R; McKoryk, Michael; Brisson, Andre L; Sparrey, Carolyn J

    2017-01-26

    Manufacturers recommend removing fall protection system components from service for any indication of weld spatter or tool damage; however, little is known about the specific effects of lanyard damage on fall arrest dynamics. Thirty-two energy absorbing lanyards were drop tested after being damaged with weld spatter, plasma torches and cutting tools and compared with new, undamaged lanyards. Two lanyards damaged with a plasma torch failed completely without deploying the energy absorber while weld spatter damage and tool cuts, up to 2/3 through the width of the webbing, had no effect on fall arrest dynamics. The results highlight the catastrophic implications of high temperature damage to lanyard webbing resulting from plasma torches - which require immediate removal from service. In addition, the integrated energy absorber design in bungee style lanyards makes them more susceptible to damage anywhere along its length. We therefore recommended against bungee lanyards for ironworkers and welders.

  13. 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

  14. Materials and welding engineering in advanced coal utilization plants

    Energy Technology Data Exchange (ETDEWEB)

    Schuhmacher, D.; Schulze-Frielinghaus, W.; Puetz, J.; Eichhorn, F.; Gaever, E. van

    1983-08-01

    The authors present the findings of studies on welding methods for high-temperature alloys used in advanced coal gasification plants. They discuss weld preparation, automatic TIG welding, MIG welding (also with pulsed arc) and plasma arc welding. The mechanical properties of welded joints before and after age hardening are investigated, and the results of fatigue and corrosion tests are presented. The welding methods are compared with a view to their suitability for high-temperature materials.

  15. Molecular dynamics study on welding a defected graphene by a moving fullerene

    Energy Technology Data Exchange (ETDEWEB)

    Cai, Kun, E-mail: kuncai99@163.com [College of Water Resources and Architectural Engineering, Northwest A& F University, Yangling 712100 (China); Research School of Engineering, The Australian National University, ACT 2601 (Australia); Wan, Jing; Yu, Jingzhou; Cai, Haifang [College of Water Resources and Architectural Engineering, Northwest A& F University, Yangling 712100 (China); Qin, Qinghua [Research School of Engineering, The Australian National University, ACT 2601 (Australia)

    2016-07-30

    Highlights: • Fullerene (FN) is adopted to weld the gap on a graphene (GN) sheet using molecular dynamics simulation. • The mechanism is that the dangling sp{sup 1} carbon atoms on both sides of gap are excited by FN to form new sp{sup 2}-sp{sup 2} carbon bonds. • The velocity of FN influences the welding result due to the fact that the deformation of GN depends on the velocity of FN. • A complex nanostructure, e.g., cone, can be formed by the present method, which will be applicable in nano fabrication/manufacturing. - Abstract: When a composite nanostructure is fabricated through van der Waals interaction only, the interaction among components may be sensitive to environmental conditions. To endow such a structure with relative stability, new covalent bonds should be applied. In this paper, a welding method for welding a circular graphene with a defect gap through a moving fullerene (C240 or C540 buckyball) is presented. When the buckyball moves above the gap, the two faces of the gap are attracted to each other and the distance between the two faces is shortened. When the dangling carbon atoms on both faces of the gap are excited to form new normal sp{sup 2}-sp{sup 2} carbon bonds, the gap can be sewn up quickly. Molecular dynamics simulations are presented to demonstrate the welding process. When the gap is a sector, an ideal cone can be fabricated using the present method.

  16. Fatigue Crack Growth Rate Test Results for Al-Li 2195 Parent Metal, Variable Polarity Plasma Arc Welds and Friction Stir Welds

    Science.gov (United States)

    Hafley, Robert A.; Wagner, John A.; Domack, Marcia S.

    2000-01-01

    The fatigue crack growth rate of aluminum-lithium (Al-Li) alloy 2195 plate and weldments was determined at 200-F, ambient temperature and -320-F. The effects of stress ratio (R), welding process, orientation and thickness were studied. Results are compared with plate data from the Space Shuttle Super Lightweight Tank (SLWT) allowables program. Data from the current series of tests, both plate and weldment, falls within the range of data generated during the SLWT allowables program.

  17. Chronic exposure to the ultraviolet radiation levels from arc welding does not result in obvious damage to the human corneal endothelium.

    Science.gov (United States)

    Oblak, Emil; Doughty, Michael J

    2002-11-01

    Occupational exposure of the cornea to ultraviolet radiation (UVR, e.g. in welding) is a well-known cause of 'arc eye' (photo-keratoconjunctivitis), but has also been considered to be a risk for the development of alterations in the size (polymegethism) and shape (pleomorphism) of the deeper-lying human corneal endothelial cells. Human data are however limited and so a further study was undertaken, with a control group. Non-contact specular micrographs of the central region of the corneal endothelium were obtained from 40 white males aged between 32 and 63 years; 20 were arc welders with an average of 25 +/- 7 years job experience, while the others were office workers (n = 20). All the welders reported occupational exposure to UVR (i.e. welders 'flashes') and up to 3 times per year. None of the subjects had a history of contact lens wear, major eye disease or surgery. The endothelial image was scanned, projected onto an overlay and cell border marking carried out in a masked fashion. The overlay was independently analysed, by a customised semi-automated method, providing cell-border-adjusted data on cell areas and cell shape (sides) on 124 to 260 cells per image. The endothelial cell density (ECD) values were also calculated from individual cell area values. All corneas appeared to be healthy, and showed no fluorescein staining indicating damage to the surface epithelium. Central corneal thickness values were normal at 0.531 +/- 0.031 (mean +/- SD) and 0.527 +/- 0.036 mm in the welders and non-welders respectively. All endothelia appeared healthy, with no evidence of cell oedema. The group-mean endothelial cell area was 393 +/- 35 and 392 +/- 21 microm2, ECD values were 2855 +/- 224 cells mm(-2) and 2852 +/- 210 cells mm(-2), while the percentages of 6-sided cells were 60 +/- 5.2 and 59 +/- 4.1% respectively. Cell area distributions were statistically identical (p > or = 0.8), and cell area-side relationships were marginally, but not statistically different. This

  18. The effect of welding fixtures on welding distortions

    OpenAIRE

    2007-01-01

    Purpose: of this paper is to examine the effect of welding fixture used to prevent the distortions duringcooling process utilizing a robot controlled gas metal arc welding method on cooling rate and distortions ofwelded structures.Design/methodology/approach: Using a specially designed welding fixture for a welded steel structure, sixdifferent types of AISI 1020 steel specimens are tested in three different welding speeds and two differentcooling conditions either at fixture or without using ...

  19. STUDIES OF ACOUSTIC EMISSION SIGNATURES FOR QUALITY ASSURANCE OF SS 316L WELDED SAMPLES UNDER DYNAMIC LOAD CONDITIONS

    Directory of Open Access Journals (Sweden)

    S. V. RANGANAYAKULU

    2016-10-01

    Full Text Available Acoustic Emission (AE signatures of various weld defects of stainless steel 316L nuclear grade weld material are investigated. The samples are fabricated by Tungsten Inert Gas (TIG Welding Method have final dimension of 140 mm x 15 mm x 10 mm. AE signals from weld defects such as Pinhole, Porosity, Lack of Penetration, Lack of Side Fusion and Slag are recorded under dynamic load conditions by specially designed mechanical jig. AE features of the weld defects were attained using Linear Location Technique (LLT. The results from this study concluded that, stress release and structure deformation between the sections in welding area are load conditions major part of Acoustic Emission activity during loading.

  20. Analysis on Characteristic of Ultra High Frequency Pulsed Gas Tungsten Arc Welding Process%超高频脉冲GTAW工艺特性分析

    Institute of Scientific and Technical Information of China (English)

    齐铂金; 杨舟; 杨明轩; 从保强

    2016-01-01

    基于5 mm厚的Ti-6Al-4V钛合金平板,分别采用常规钨极氩弧焊(Conventional gas tungsten arc welding, C-GTAW)和超高频脉冲钨极氩弧焊(Ultra high frequency pulsed GTAW, UHFP-GTAW)工艺,选用相同平均电流(60 A)进行焊接,同时利用FLUKE Ti400红外热像仪对熔池中心温度进行实时监测,分别对电弧定点燃烧时、以50 mm/min焊速移动时采集的熔池中心温度进行分析。由测量结果可知,与相同条件下C-GTAW相比,UHFP-GTAW作用下的熔池中心温度最大值增加了10~40 K,表明该工艺具有更高的能量密度。分析1.5 mm钛合金对接工艺试验的组织性能测试结果发现,焊缝区细小均匀的针状α'马氏体形成的网篮组织含量增加,热影响区组织α'相呈现短且小的针状且排列更为致密,可改善接头的拉伸力学性能、疲劳性能。UHFP-GTAW焊缝的伸长率最小增幅为30%,断面收缩率最小增幅为50%,疲劳寿命至少增加2倍。%Bead-on-plate welding test are carried on 5 mm thickness Ti-6Al-4V titanium alloy plates by the processes both of conventional gas tungsten arc welding (C-GTAW) and the ultra high frequency pulsed GTAW (UHFP-GTAW) in the same average welding current (60 A). The temperature of molten pool center is monitored in real time with thermal infrared imager Fluke Ti400. These measurements before the arc moving and moving at a speed of 50 mm/min are analyzed respectively. The results show that compared with the C-GTAW in same condition, the maximum of the temperature of weld pool center are 10-40 K enhanced by UHFP-GTAW for higher density power with different pulse frequencies. The microstructure and mechanical properties tests are conducted on 1.5 mm thickness Ti-6Al-4V butt joints, verified that the UHFP-GTAW had influences in improving tensile and fatigue properties because of a larger density of basketweave formed by the short and uniform acicularα' martensite in fusion zone and a more

  1. Plasma-MIG hybrid arc welding with PID increment constant current or voltage control algorithm%增量型PID恒流恒压控制的Plasma-MIG复合电弧焊接

    Institute of Scientific and Technical Information of China (English)

    杨涛; 张生虎; 高洪明; 吴林; 许可望; 刘永贞

    2013-01-01

    Plasma-MIG复合电弧焊接对电源的外特性输出及焊接过程控制有着很高的要求,以VC++软件开发工具为平台,推导了适合于Plasma-MIG复合电弧焊接的增量型PID控制算法,实现了对复合电弧焊接过程控制及电源外特性的要求.结果表明,增量型PID恒流恒压控制能够满足Plasma-MIG对电源外特性的输出要求.Plasma电弧和MIG电弧并不是相互独立的,两者以共享的电磁空间、导电气氛和焊丝为媒介建立起耦合关系.Plasma-MIG复合电弧焊接过程中,增量型PID控制下的Plasma电弧能够自发的调节自身电参数,来稳定电弧空间的电流密度,使得焊接过程中无飞溅.采用控制后,Plasma-MIG复合电弧焊焊接过程焊缝铺展好,焊接过程稳定,焊缝成形好.%Output characteristics of the power supply and welding process control are important factors for plasma-MIG hybrid arc welding. PID increment control algorithm suitable for Plasma-MIG hybrid arc welding was developed based on VC + + language in this paper, which optimized the output characteristics of the power supply and welding process control. The results show that the plasma arc and MIG arc were coupled with each other by sharing the electro-magnetic space, gas and filler metal. Plasma are controlled by PID increment control algorithm was capable of stabilizing the current density through the arc due to its self-adjusting function, without sputtering in the welding process. High stability, molten metal with excellent liquidity and weld with smooth surface were realized by plasma-MIG hybrid arc welding with PID increment control algorithm.

  2. Assessment of Corona/Arcing Hazard for Electron Beam Welding in Space Shuttle Bay at LEO for ISWE: Test Results

    Science.gov (United States)

    Nunes, A. C., Jr.; Russell, C.; Vaughn, J.; Stocks, C.; ODell, D.; Bhat, B.

    1996-01-01

    Test welds were made in argon over a range of pressures from 10-5 to 10-3 torr (the latter pressure an order of magnitude above pressures anticipated in the space shuttle bay during welding) with and without plasma on 304 stainless steel, 6Al-4V titanium, and 5456 aluminum in search of any possible unwanted electrical discharges. Only a faint steady glow of beam-excited atoms around the electron beam and sometimes extending out into the vacuum chamber was observed. No signs of current spiking or of any potentially dangerous electrical discharge were found.

  3. Reliability analysis of kinematic accuracy of 6-DOF arc welding robot%六自由度弧焊机器人的运动可靠性分析

    Institute of Scientific and Technical Information of China (English)

    张晓瑾; 谢里阳; 李佳; 武滢; 张宇

    2011-01-01

    Although a few studies have analyzed repeatability, accuracy, errors and safety of robot, little attention has been paid to the stochastic approach with open-loop mechanisms, especially robot manipulators. Considering the random nature of dimensional tolerance and clearance in manufacturing and assembling operations, a stochastic approach to figure out reliabilitv of the robot should be required. In this paper, reliability is used to reflect the ability of 6-DOF arc welding robot in completing tasks safely and accurately. With the assumption that all kinematic parameters are independent random variables following normal distribution, the kinematic accuracy error model and reliability model are presented based on the Denavt-Hartenberg ( D-H) representation and error propagation theory.

  4. 浅析铸铁补焊中CO2气体保护焊的应用%Analysis of Cast Iron Welding in CO2 Gas Shielded Arc Welding Applications

    Institute of Scientific and Technical Information of China (English)

    甘宜坚

    2014-01-01

    在工业生产过程中,传统的补焊铸铁类机件应用的是焊条电弧焊。但是,这种方法的成本较高,且生产效率较低,无法实现对产品质量的准确控制,已经不能满足新时期工业生产的要求。CO2气体保护焊的出现,解决了这一难题,为工业生产的发展提供了有效的保障。%In industrial processes, the traditional cast iron parts welding applications is SMAW. However, the high cost of this approach, and low productivity, can not achieve accurate control of product quality, has been unable to meet the requirements of the new era of industrial production. CO2 gas shielded arc welding appear to solve this problem for the development of industrial production provides effective protection.

  5. Analytical Solution for Model-Based Dynamic Power Factor Measurement in AC Resistance Spot Welding

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    On the basis of welding transformer circuit model, a new measuring method was proposed. This method measures the peak angle of the welding current, and then calculates the dynamic power factor in each half-wave.An artificial neural network is trained and used to generate simulation data for the analytical solution, i.e. a highorder binary polynomial, which can be easily adopted to calculate the power factor online. The tailored sensing and computing system ensures that the method possesses a real-time computational capacity and satisfying accuracy. A DSP-based resistance spot welding monitoring system was developed to perform ANN computation. The experimental results suggest that this measuring method is feasible.

  6. 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.

  7. Microstructure and dynamic tensile behavior of DP600 dual phase steel joint by laser welding

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Danyang, E-mail: dongdanyang@mail.neu.edu.cn [College of Science, Northeastern University, No. 11, Lane 3, WenHua Road, HePing District, Shenyang 110819 (China); Liu, Yang, E-mail: liuyang@mail.neu.edu.cn [Key Laboratory for Anisotropy and Texture of Materials, Ministry of Education, Northeastern University, Shenyang 110819 (China); Yang, Yuling, E-mail: yulingyang@mail.neu.edu.cn [College of Science, Northeastern University, No. 11, Lane 3, WenHua Road, HePing District, Shenyang 110819 (China); Li, Jinfeng, E-mail: lijinfengboda@163.com [College of Science, Northeastern University, No. 11, Lane 3, WenHua Road, HePing District, Shenyang 110819 (China); Ma, Min, E-mail: sharon6789@163.com [College of Science, Northeastern University, No. 11, Lane 3, WenHua Road, HePing District, Shenyang 110819 (China); Jiang, Tao, E-mail: tao.jiang906@yahoo.com [College of Science, Northeastern University, No. 11, Lane 3, WenHua Road, HePing District, Shenyang 110819 (China)

    2014-01-31

    Dual phase (DP) steels have been widely used in the automotive industry to reduce vehicle weight and improve car safety. In such applications welding and joining have to be involved, which would lead to a localized change of the microstructure and property, and create potential safety and reliable issues under dynamic loading. The aim of the present study is to examine the rate-dependent mechanical properties, deformation and fracture behavior of DP600 steel and its welded joint (WJ) produced by Nd:YAG laser welding over a wide range of strain rates (0.001–1133 s{sup −1}). Laser welding results in not only significant microhardness increase in the fusion zone (FZ) and inner heat-affected zone (HAZ), but also the formation of a softened zone in the outer HAZ. The yield strength (YS) of the DP600 steel increases and the ultimate tensile strength (UTS) remains almost unchanged, but the ductility decreases after welding. The DP600 base metal (BM) and WJ are of positive strain rate sensitivity and show similar stress–strain response at all studied strain rates. The enhanced ductility at strain rates ranging from 1 to 100 s{sup −1} is attributed to the retardation of the propagation of plastic strain localization due to the positive strain rate sensitivity and the thermal softening caused by deformation induced adiabatic temperature rise during dynamic tensile deformation. The tensile failure occurs in the inner HAZ of the joint and the distance of failure location from the weld centerline decreases with increasing strain rate. The mechanism for the changing failure location can be related to the different strain rate dependence of the plastic deformation behavior of the microstructures in various regions across the joint. The DP600 WJ absorbs more energy over the whole measured strain rates than that of the BM due to the higher strength at the same strain when the deformation only up to 10% is considered.

  8. The Dynamics and Sliding Mode Control of Multiple Cooperative Welding Robot Manipulators

    OpenAIRE

    Bin Zi; Huihui Sun; Zhencai Zhu; Sen Qian

    2012-01-01

    This paper deals with the design, dynamic modelling and sliding mode control of multiple cooperative welding robot manipulators (MWRMs). The MWRMs can handle complex tasks that are difficult or even impossible for a single manipulator. The kinematics and dynamics of the MWRMs are studied on the basis of the Denavit‐Hartenberg and Lagrange method. Following that, considering the MWRM system with nonlinear and unknown disturbances, a non‐singular terminal sliding mode control strategy is design...

  9. Research on Mechanism of Deformation Reduced by CO2 Gas Shielded Arc Welding%CO2气体保护焊降低焊接变形机理研究

    Institute of Scientific and Technical Information of China (English)

    李汉文; 宗培; 杨铁磊

    2011-01-01

    为了研究CO2气体保护焊强制对流对焊接变形的影响,通过分析多种换热边界条件,分别确定了适用于自然对流和有强制对流效果的气体保护焊的对流辐射边界条件计算公式,计算得出综合换热系数.在此基础上对手工焊和CO2焊焊接应力应变进行计算分析.结果表明,CO2焊保护气体形成的强制对流而形成的冷却环境是其降低焊接变形的重要因素.%The influences of forced convection on the welding deformation of CO2 gas shielded arc welding were investigated. The formula of the combined coefficient, including convection coefficient and radiation coefficient, was obtained by analyzing two convection boundary conditions, which considers natrual convection and force convection, seperately. Based on these two conditions, the deformation of butt welding plate with 3 mm was simulated. The stimulation results show that compared with manual welding, the force convection boundary condition of CO2 gas shielded arc welding is a critical factor to form less deformation.

  10. Effects of laser power density on static and dynamic mechanical properties of dissimilar stainless steel welded joints

    Institute of Scientific and Technical Information of China (English)

    Yan-Peng Wei; Mao-Hui Li; Gang Yu; Xian-Qian Wu; Chen-Guang Huang; Zhu-Ping Duan

    2012-01-01

    The mechanical properties of laser welded joints under impact loadings such as explosion and car crash etc.are critical for the engineering designs. The hardness,static and dynamic mechanical properties of AISI304 and AISI316L dissimilar stainless steel welded joints by CO2 laser were experimentally studied. The dynamic strain-stress curves at the strain rate around 103 s-1 were obtained by the split Hopkinson tensile bar (SHTB).The static mechanical properties of the welded joints have little changes with the laser power density and all fracture occurs at 316 L side.However,the strain rate sensitivity has a strong dependence on laser power density.The value of strain rate factor decreases with the increase of laser power density.The welded joint which may be applied for the impact loading can be obtained by reducing the laser power density in the case of welding quality assurance.

  11. 58SiMn钢手工氩弧焊接常见缺陷及其控制%The common defects and control of 58SiMn steel ahoy manual argon tungsten arc welding

    Institute of Scientific and Technical Information of China (English)

    李胜鑫

    2013-01-01

    58SiMn steel alloy with its high mechanical strength, high, hardness higher characteristic its quench-hardening ability, widely used in weapons industry,and in the weapon design as the major parts of material in the selected dominant.Argon arc welding has its special features about the arc heat concentrated,heat affected zone is very narrow,small the welding stress and deformation is small,the welding process stability,arc energy parameters accuracy can control,good stability and arc the heat loss lesscan stable combustion for welding quality good.Argon is insoluble in the liquid metal,also not with metal up any chemical reaction,effectively preventing the oxygen,nitrogen,invading weld metal,but also to meet the production.%58SiMn钢以其机强度高、淬透性高、硬度高等特点,在弹药行业得到广泛应用,并在设计中作为主要部件材料选择中占据主导地位.氩弧焊具有电弧热量集中,热影响区很窄,焊接应力与变形小,焊接过程稳定,电弧能量参数可精确控制,稳定性好,电弧的热量损失少,能够稳定燃烧,焊接质量好,氩气既不溶于液态金属,也不与金属起任何化学反应,有效阻止氧、氮等侵入焊缝金属等特点,能够满足生产.

  12. 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.

  13. A study on twin-tungsten TIG welding method

    Institute of Scientific and Technical Information of China (English)

    Leng Xuesong; Zhang Guangjun; Gao Hongming; Wu Lin

    2006-01-01

    A new twin-tungsten TIG (T-TIG) welding method was studied. This method differs from the conventional TIG method, it places two electrodes insulated from each other in the same welding torch, and a coupling arc is generated from the two electrodes. The coupling arc pressure was measured and preliminary welding experiment was made. The results show that the coupling arc can keep arc pressure at a low level compared with conventional TIG arc, and welding can be achieved under higher current and high travel speed with sound appearance of weld. Therefore, this new method can applied widely in high efficiency welding.

  14. Comparison of volumetric-modulated arc therapy and dynamic conformal arc treatment planning for cranial stereotactic radiosurgery.

    Science.gov (United States)

    Molinier, Jessica; Kerr, Christine; Simeon, Sebastien; Ailleres, Norbert; Charissoux, Marie; Azria, David; Fenoglietto, Pascal

    2016-01-08

    The aim was to analyze arc therapy techniques according to the number and position of the brain lesions reported by comparing dynamic noncoplanar conformal arcs (DCA), two coplanar full arcs (RAC) with volumetric-modulated arc therapy (VMAT), multiple noncoplanar partial arcs with VMAT (RANC), and two full arcs with VMAT and 10° table rotation (RAT). Patients with a single lesion (n= 10), multiple lesions (n = 10) or a single lesion close to organs at risk (n = 5) and previously treated with DCA were selected. For each patient, the DCA treatment was replanned with all VMAT techniques. All DCA plans were compared with VMAT plans and evaluated in regard to the different quality indices and dosimetric parameters. For single lesion, homogeneity index (HI) better results were found for the RANC technique (0.17 ± 0.05) compared with DCA procedure (0.27± 0.05). Concerning conformity index (CI), the RAT technique gave higher and better values (0.85 ± 0.04) compared with those obtained with the DCA technique (0.77 ± 0.05). DCA improved healthy brain protection (8.35 ± 5.61 cc vs. 10.52 ± 6.40 cc for RANC) and reduced monitor unit numbers (3046 ± 374 MU vs. 4651 ± 736 for RANC), even if global room occupation was higher. For multiple lesions, VMAT techniques provided better HI (0.16) than DCA (0.24 ± 0.07). The CI was improved with RAT (0.8 ± 0.08 for RAT vs. 0.71 ± 0.08 for DCA). The V10Gy healthy brain was better protected with DCA (9.27 ± 4.57 cc). Regarding the MU numbers: RANC < RAT< RAC < DCA. For a single lesion close to OAR, RAT achieved high degrees of homogeneity (0.27 ± 0.03 vs. 0.53 ± 0.2 for DCA) and conformity (0.72± 0.06vs. 0.56 ± 0.13 for DCA) while sparing organs at risk (Dmax = 12.36 ± 1.05Gyvs. 14.12 ± 0.59 Gy for DCA, and Dmean = 3.96 ± 3.57Gyvs. 4.72 ± 3.28Gy for DCA). On the other hand, MU numbers were lower with DCA (2254 ± 190 MUvs. 3438 ± 457 MU for RANC) even if overall time was inferior with RAC. For a single lesion, DCA

  15. Gas tungsten arc welder

    Science.gov (United States)

    Christiansen, D.W.; Brown, W.F.

    A welder for automated closure of fuel pins by a gas tungsten arc process in which a rotating length of cladding is positioned adjacent a welding electrode in a sealed enclosure. An independently movable axial grinder is provided in the enclosure for refurbishing the used electrode between welds.

  16. Research and application of double-wires submerged arc welding in shipbuilding industry%双丝埋弧焊在造船业的应用和探索

    Institute of Scientific and Technical Information of China (English)

    刘海清; 徐雁飞; 吕德华; 胡建华; 汪亮

    2012-01-01

    The efficient double wires submerged arc welding process which was used in shipbuilding industry in certain range of heat input condition,that accurately balance the various parameters for the welding joint according to related code,which welding procedure specification was approved by China Classification Society and fitting the requirement of volume-production in workshop. The obviously changing of molten pool liquid metal crystal angle direction was observed with comparing the single, double wires welding joint microstructure, the phenomenon was speculated as somehow logical function between the welding pool surface tension and temperature, welding pool surface tension depends on the size of the molten pool temperature distribution on the surface, and the surface tension of welding pool is the main driving force to affect the fluidity of liquid metal in the welding pool.When the temperature field from the arc of the superimposing second wire with the relative high voltage and low current cause the new thermal cycle, and transfer the whole molten pool liquid metal crystal angle direction.That is different to the view of single wire submerged arc welding current penetration depth {depth of penetration coefficient) and single molten pool.%造船业采用高效的双丝埋弧焊法,在焊接线能量一定的条件下,针对性很强地匹配各焊接参数以获得符合规范要求的焊接接头,同时满足CCS有关焊接工艺认可要求,并适用于车间大生产.通过单、双丝焊接接头金相对比观察到熔池液体金属结晶角度方向产生很大变化,认为其原因在于焊接熔池的表面张力与温度为函数关系,熔池表面张力大小取决于熔池表面上的温度分布,而熔池表面张力是影响熔池内液体金属流动的主要驱动力,当大电压、小电流的后丝电弧叠加时的温度场形成新的热循环改变了整个熔池液体金属结晶角度方向,不同于单丝埋孤焊焊接电流熔

  17. Multiphysics Modeling and Simulations of Mil A46100 Armor-Grade Martensitic Steel Gas Metal Arc Welding Process

    Science.gov (United States)

    2013-05-23

    structure. To experimentally characterize the microstructure of GMAW joints, the following three real-time and post- mortem techniques have been...generally employed: (a) dila- tometry (Ref 13); (b) spatially and time-resolved x-ray diffraction (Ref 7); and (c) post- mortem weld-region material...the maximum exposure temperature is between Ac1 and Ac3, austenitization becomes incomplete but the attendant austenite pos - sesses higher

  18. Research on Arc Welding Technology of Tube-to-Tube in Sheet Columbium Heat Exchanger%铌制固定管板式换热器换热管与管板的焊接工艺性研究

    Institute of Scientific and Technical Information of China (English)

    毛辉; 叶建林; 董斌; 张成

    2012-01-01

    The difficulties of present studies on welding columbium tube to columbium tube sheet were briefly reviewed. Effects of welding parameters on qualities of welding joints were analyzed. The results show that specific welding structures such as slot and expansion joint change the heat conduction boundary condition of welding joints which had positive effects on welding. He-Ar mixed gas, as shielding gas, can improve the arc stiffness, thermal efficiency and penetration.%介绍了铌换热管与管板的焊接难点及在焊接过程中的解决措施.探讨了不同焊接工艺参数对焊接接头质量的影响.结果表明,采用带焊接槽和贴胀的接头结构可以改变接头的导热边界条件,有利于铌换热管与管板的焊接;采用氩气和氦气的混合气体作保护气可以提高电弧挺度、电弧热效率和焊缝熔深.

  19. NON-EQUILIBRIUM STATIONARY STATE IN CHEMICAL REACTION OF SiO2/Fe AT INTERFACE OF SLAG/METAL AND ITS STABILITY DURING ARC WELDING

    Institute of Scientific and Technical Information of China (English)

    LI Xiaoquan; DU Zeyu; YANG Xuguang

    2007-01-01

    For characteristics of open and far from thermodynamic equilibrium in welding chemical reaction, a new kind of quantitative method, which is used to analyze direction and extent for chemical reaction of SiO2/Fe during quasi-steady state period, is introduced with the concept of non-equilibrium stationary state. The main idea is based on thermodynamic driving forces, which result in non-zero thermodynamic fluxes and lead to chemical reaction far away from thermodynamic equilibrium. There exists certain dynamic equilibrium relationship between rates of diffusion fluxes in liquid phase of reactants or products and the rate equation of chemical reaction when welding is in quasi-steady state. As result of this, a group of non-linear equations containing concentrations of all substances at interface of slag/liquid-metal may be established. Moreover the stability of this non-equilibrium stationary state is discussed using dissipative structure theory and it is concluded theoretically that this non-equilibrium stationary state for welding chemical reaction is of stability.

  20. 钢轨自保护药芯焊丝自动窄间隙电弧焊工艺及装备研究%Technology and equipment development of self-shielded flux cored narrow gap arc rail welding

    Institute of Scientific and Technical Information of China (English)

    宋宏图; 李力; 丁韦; 季关钰

    2011-01-01

    无缝线路建设的大范围展开迫切需要性能、质量、生产效率相匹配的原位焊接方法,目前使用最多的为铝热焊和电弧焊.介绍了窄间陈电弧焊在钢轨焊接中的应用,并重点对电弧位置实时检测技术和自保护药芯焊丝自动钢轨窄间隙电弧焊工艺及装备进行了说明.进行接头性能试验,结果表明:采用钢轨自保护药芯焊丝自动窄间隙电弧焊焊接的接头性能良好,完全超过另外一种原位焊接方法铝热焊的接头性能,能够通过铝热焊不能通过的落锤试验,拉伸性能也强于铝热焊,冲击性能大幅度优于目前使用的闪光焊、气压焊和铝热焊.%Higher joint quality and performance good production efficiency in situ rail welding method should be developed for jointless railway wide construction. Nowadays most ways in used are thermit welding and arc welding. In this paper,narrow gap are welding used in rail welding is introduced,especially on our study of automatic narrow gap are rail welding using self-shielded flux cored wire and based on are position vision detection.Joint properties is overall better than another method thermit welding of in situ welding joint performance,can pass through the drop hammer test,tensile properties is also stronger than thermit welding,the impact performance significantly better than the currently used flash welding, gas pressure welding and thermit welding.

  1. Effects of the laser beam superficial heat treatment on the gas Tungsten arc Ti-6al-4v welded metal microstructure

    Science.gov (United States)

    Voiculescu, I.; Dontu, Octavian; Geanta, V.; Ganatsios, S.

    2008-03-01

    The microstructure of the weld and the extent to which it is different from the thermo-mechanically processed base material is strongly influenced by the thermal cycle of welding. The mechanical properties of composite weld structures in titanium alloys depend on structural characteristics of each region (weld, base material and heat affected area), influenced by the specific thermal cycle imposed during welding and the subsequent post-weld heat treatment. In order to improve the as-welded metal toughness and ductility, the welded metal was subjected to various post weld laser heat treatments, above and below beta transus temperature in a shielding atmosphere of pure argon. Standard micro-hardness measurements and tensile strength techniques showed higher mechanical properties of the heat treated samples in different conditions with respect to the base metal. Metallographic investigations attribute this to the formation of α'phases in heat treated material, especially in the weld metal.

  2. Cardiac Exposure in the Dynamic Conformal Arc Therapy, Intensity-Modulated Radiotherapy and Volumetric Modulated Arc Therapy of Lung Cancer.

    Directory of Open Access Journals (Sweden)

    Xin Ming

    Full Text Available 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.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 commercial treatment planning system and have been clinically accepted and delivered. The dose distribution to the heart and the effects of tumor laterality, the irradiated heart volume and the beam-to-heart distance on the cardiac exposure were investigated.The mean dose to the heart among all 140 plans was 4.5 Gy. Specifically, the heart received on average 2.3, 5.2 and 4.6 Gy in the DCAT, IMRT and VMAT plans, respectively. The mean heart doses for the left and right lung tumors were 4.1 and 4.8 Gy, respectively. No patients died with evidence of cardiac disease. Three patients (2% with preexisting cardiac condition developed cardiac disease after treatment. Furthermore, the cardiac exposure was found to increase linearly with the irradiated heart volume while decreasing exponentially with the beam-to-heart distance.Compared to old technologies for lung cancer treatment, modern radiotherapy treatment modalities demonstrated better heart sparing. But the heart dose in lung cancer radiotherapy is still higher than that in the radiotherapy of breast cancer and Hodgkin's disease where cardiac complications have been extensively studied. With strong correlations of mean heart dose with beam-to-heart distance and irradiated heart volume, cautions should be exercised to avoid long-term cardiac toxicity in the lung cancer patients undergoing radiotherapy.

  3. Thermal Stir Welding Development at Marshall Space Flight Center

    Science.gov (United States)

    Ding, Robert J.

    2008-01-01

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

  4. Self-Reacting Friction Stir Welding for Aluminum Alloy Circumferential Weld Applications

    Science.gov (United States)

    Bjorkman, Gerry; Cantrell, Mark; Carter, Robert

    2003-01-01

    Friction stir welding is an innovative weld process that continues to grow in use, in the commercial, defense, and space sectors. It produces high quality and high strength welds in aluminum alloys. The process consists of a rotating weld pin tool that plasticizes material through friction. The plasticized material is welded by applying a high weld forge force through the weld pin tool against the material during pin tool rotation. The high weld forge force is reacted against an anvil and a stout tool structure. A variation of friction stir welding currently being evaluated is self-reacting friction stir welding. Self-reacting friction stir welding incorporates two opposing shoulders on the crown and root sides of the weld joint. In self-reacting friction stir welding, the weld forge force is reacted against the crown shoulder portion of the weld pin tool by the root shoulder. This eliminates the need for a stout tooling structure to react the high weld forge force required in the typical friction stir weld process. Therefore, the self-reacting feature reduces tooling requirements and, therefore, process implementation costs. This makes the process attractive for aluminum alloy circumferential weld applications. To evaluate the application of self-reacting friction stir welding for aluminum alloy circumferential welding, a feasibility study was performed. The study consisted of performing a fourteen-foot diameter aluminum alloy circumferential demonstration weld using typical fusion weld tooling. To accomplish the demonstration weld, weld and tack weld development were performed and fourteen-foot diameter rings were fabricated. Weld development consisted of weld pin tool selection and the generation of a process map and envelope. Tack weld development evaluated gas tungsten arc welding and friction stir welding for tack welding rings together for circumferential welding. As a result of the study, a successful circumferential demonstration weld was produced leading

  5. 连续管管-管对接自动焊电弧偏吹现象的探讨%Discussion on Partial Arc Blow Phenomenon During Continuous Pipe-pipe Butt Welding

    Institute of Scientific and Technical Information of China (English)

    王维亮; 石凯; 刘彦明; 张伟妮

    2011-01-01

    In all-position automatic TIG butt welding for coiled tubing, arc blowing phenomenon often occurs. The analysis show that the main reasons for partial arc blow are small line energy, wire unstable, ground connection uncorrection, poor weld shape, edge preparationing unstandard, convection and other inappropriate welding parameters.The measures for avoiding or reducing the arc blowing partial are put forward.%在连续管全位置自动TIG对接焊中,经常会出现电弧偏吹现象.分析表明,引起电弧偏吹的主要原因有小线能量、送丝不稳定、地线连接不正确、焊道成型差、坡口加工不规范、热对流、焊接工艺参数不合适等.根据分析,提出了避免或减小电弧偏吹的措施.

  6. Assessing the Impact of Sequencing Practicums for Welding in Agricultural Mechanics

    Science.gov (United States)

    Rose, Malcolm; Pate, Michael L.; Lawver, Rebecca G.; Warnick, Brian K.; Dai, Xin

    2015-01-01

    This study examined the impact of sequencing practicums for welding on students' ability to perform a 1F (flat position-fillet lap joint) weld on low-carbon steel. Participants were randomly assigned a specific practice sequence of welding for using gas metal arc welding (GMAW) and shielded metal arc welding (SMAW). A total of 71 participants…

  7. Auto Body Welding 2 (Course Outline), Automotive Body Repair and Refinishing 1: 9033.04.

    Science.gov (United States)

    Dade County Public Schools, Miami, FL.

    The 90-hour course is a foundation quinmester course in welding for the auto body repairman. The outline consists of seven blocks of instruction (orientation, 6 hours; auto body oxyacetylene welding, 10 hours; electric arc welding equipment, 6 hours; auto body electric arc welding, 8 hours; position welding, 40 hours; electric spot welders, 16…

  8. Real-time monitoring of weld penetration quality in roboticarc welding process

    Institute of Scientific and Technical Information of China (English)

    Wu Chuansong; Jia Chuanbao; Duan Xiaoning

    2008-01-01

    It is of great significance to develop an intelligent monitoring system for weld penetration defects such as incomplete penetration and burn-through in real-time during robotic arc welding process. In this paper, robotic gas metal arc welding experiments are carried out on the mild steel test pieces with Vee-type groove. Through-the-arc sensing method is used to capture the transient values of the welding voltage and current. The raw data of the captured welding current and voltage are processed statistically, and the feature vector S10 is extracted to correlate the welding conditions to the weld penetration information. It lays foundation for intelligent monitoring of weld quality in robotic arc welding.

  9. Thermal efficiency on welding of AA6061-T6 alloy by modified indirect electric arc and current signals digitalisation; Eficiencia termica en soldadura de la aleacion AA6061-T6 por arco electrico indirecto modificado y digitalizacion de senales de intensidad de corriente

    Energy Technology Data Exchange (ETDEWEB)

    Ambriz, R. R.; Barrera, G.; Garcia, R.; Lopez, V. H.

    2009-07-01

    The results of the thermal efficiency on welding by modified indirect electric arc technique (MIEA) [1] of the 6061- T6 aluminum alloy are presented. These values are in a range of 90 to 94 %, which depend of the preheating employed. Thermal efficiency was obtained by means of a balance energy which considers the heat input, the amount of melted mass of the welding profiles, and welding parameters during the joining, especially of the arc current data acquisition. Also, some dimensionless parameters were employed in order to determine the approximation grade of the melted pool, the heat affected zone (HAZ), and their corresponding values with the experimental results. (Author) 13 refs.

  10. Welding Curtains

    Science.gov (United States)

    1984-01-01

    Concept of transparent welding curtains made of heavy duty vinyl originated with David F. Wilson, President of Wilson Sales Company. In 1968, Wilson's curtains reduced glare of welding arc and blocked ultraviolet radiation. When later research uncovered blue light hazards, Wilson sought improvement of his products. He contracted Dr. Charles G. Miller and James B. Stephens, both of Jet Propulsion Laboratory (JPL), and they agreed to undertake development of a curtain capable of filtering out harmful irradiance, including ultraviolet and blue light and provide protection over a broad range of welding operation. Working on their own time, the JPL pair spent 3 years developing a patented formula that includes light filtering dyes and small particles of zinc oxide. The result was the Wilson Spectra Curtain.

  11. Welding technology for rails. Rail no setsugo gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    Okumura, M.; Karimine, K. (Nippon Steel Corp., Tokyo (Japan)); Uchino, K.; Sugino, K. (Nippon Steel Corp., Kitakyushu, Fukuoka (Japan). Technical Research Inst. of Yawata Works); Ueyama, K. (JR Railway Technical Research Inst., Tokyo (Japan))

    1993-08-01

    The rail joining technology is indispensable for making long welded rails. Flush butt welding, gas welding, enclosed arc welding, and thermit welding are used properly as the welding methods. A method for improving the joint reliability by controlling the residual stress distribution of welded joint is investigated to prepare high carbon component weld metal similar to the rail. Problems with each of the welding methods and the newly developed technology to solve the problems are outlined. Composition of the coating is improved also, and a high C system welding rod is developed which has satisfactory weldability. High performance and high efficient new enclosed arc welding technology not available by now is developed which utilizes high carbon welding metal as a new EA welding work technology, and put to practical use. As a result of this study, useful guides are obtained for the establishment of satisfactory thermit welding technology. 17 refs., 16 figs., 1 tab.

  12. Wire + Arc Additive Manufacturing

    OpenAIRE

    Williams, Stewart W.; Martina, Filomeno; Addison, Adrian C.; Ding, Jialuo; Pardal, Goncalo; Colegrove, Paul A.

    2016-01-01

    Depositing large components (>10 kg) in titanium, aluminium, steel and other metals is possible using Wire + Arc Additive Manufacturing. This technology adopts arc welding tools and wire as feedstock for additive manufacturing purposes. High deposition rates, low material and equipment costs, and good structural integrity make Wire+Arc Additive Manufacturing a suitable candidate for replacing the current method of manufacturing from solid billets or large forgings, especially with regards to ...

  13. AZ31B镁合金TIG焊接件应力腐蚀性能研究%Research on the Properties of Stress Corrosion Cracking for Tungsten Inert-Gas Arc Welded AZ31B Magnesium Alloy

    Institute of Scientific and Technical Information of China (English)

    葛茂忠; 项建云; 张永康

    2013-01-01

    为了研究AZ31B镁合金钨极氩弧焊接件应力腐蚀性能,室温下采用三点加载的方式,在去离子水中对试样进行应力腐蚀试验.利用光学显微镜(OM)观测试样微观结构,利用扫描电镜(SEM)观测应力腐蚀断口,利用X-350A型X射线应力仪和CHI660B型电化学工作站分别测定试样表面残余应力和动电位极化曲线.试验结果表明:采用单面焊双面成型工艺,在45~50 A的焊接电流及合适的焊接速度条件下,焊接2.2 mm厚AZ31B镁合金薄板时,钨极氩弧焊能够获得理想的焊接接头,抗拉强度达到209 MPa;焊接件热影响区表面残余拉应力为60 MPa;同母材相比,焊接件自腐蚀电位减小27 mV,腐蚀电流增大了41.4%,从而增加焊接件腐蚀倾向;AZ31B焊接件在去离子水中浸没192 h后出现应力腐蚀开裂,属于穿晶型脆性断裂,这表明AZ31B镁合金焊接件在去离子水中具有很高的应力腐蚀敏感性.%In order to study the properties of the stress corrosion cracking (SCO for the tungsten inert-gas (TIG) arc welded AZ31B magnesium alloy sheets, the SCC susceptibility of the welded samples was assessed by three points loading method in deionized water at room temperature. The microstructure of specimens and fracture surfaces were analyzed by OM and SEM, respectively. Surface residual stress and potentiodynamic polarization behaviors of the welded samples were examined by using X-ray diffraction technology and a CHI660B electrochemical workstation, respectively. The results show that when TIG arc welding was used to weld AZ31B Mg alloy plates with the thickness of 2. 2 mm by using single-side welding double-side molding process, the ideal welding joints can be obtained at the welding current range from 45 A to 50 A and appropriate welding speed, the ultimate tensile strength of the welded joints is 209 Mpa; The residual tensile stress is 60 Mpa in the surface of heat effected zone of the welded joints; corrosion potential

  14. CO2气体保护焊短路过渡过程与电参数的关系%RELATIONSHIP BETWEEN SHORT CIRCUIT TRANSFER OF CO2 ARC WELDING AND ITS ELECTRIC PARAMETERS

    Institute of Scientific and Technical Information of China (English)

    李桓; 杨立军; 李俊岳; 邓黎丽; 张宝红

    2001-01-01

    用计算机控制的高性能数据采集系统对CO2焊短路过渡过程的电参数进行了研究.分析认为可利用电弧电压来指示熔滴短路及电弧复燃,利用电弧电压的微分来指示液体小桥缩颈,为CO2焊短路过渡实时控制奠定了基础.%The electric parameters of the short-circuit transfer of CO2 arc welding are examined totally and systematically by using an advanced data-collecting system controlled by a computer.Stadies and analysis of the above data show that the arc voltage can reflect the droplet short circuit and the arc re-start,and its differential signal can indicate the pinch of the liquid bridge.This is a better foundation for developing the real-time control of short-circuit transfer of CO2 arc welding.

  15. Study of mechanism of activating flux increasing weld penetration of AC A-TIG welding for aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    HUANG Yong; FAN Ding; FAN Qinghua

    2007-01-01

    When multi-component flux AF305 is used as surface activating flux for an aluminum alloy, the weld penetration of activating flux-tungsten inert-gas (A-TIG)welding is over two times more than that of conventional TIG welding. Using A-TIG welding with the modes of alternating current (AC), direct current electrode negative (DCEN) and direct current electrode positive (DCEP), respectively, the flux differently affects weld penetration when the polarity is different. After studied the effect of compelled arc constriction on weld penetration of AC welding, it is believed that the constriction of the whole arc root is not the main mechanism that flux AF305 dramatically improves weld penetration. The penetration has a relationship with the separate distribution of slag on the weld surface. Then, an observation of scanning electron microscopy (SEM) and an electronic data systems (EDS) analysis of slag were performed respectively. The separate distribution of slag on the weld pool during welding and the great constriction of arc spots were confirmed by TIG welding with helium shielding gas. The relationship between slag distribution and weld penetration was studied by adding aluminum powder into flux AF305 to change the distribution of slag. During welding, the separate distribution of slag on the weld pool results in the great constriction of arc spots, an increase in arc spot force, and an increase in Lorentz force within the arc and weld pool. Finally, the weld penetration is increased.

  16. Variation of chemical composition of high strength low alloy steels with different groove sizes in multi-pass conventional and pulsed current gas metal arc weld depositions

    Directory of Open Access Journals (Sweden)

    K. Devakumaran

    2015-06-01

    Full Text Available 25 mm thick micro-alloyed HSLA steel plate is welded by multi-pass GMAW and P-GMAW processes using conventional V-groove and suitably designed narrow gap with 20 mm (NG-20 and 13 mm (NG-13 groove openings. The variation of weld metal chemistry in the multi pass GMA and P-GMA weld depositions are studied by spark emission spectroscopy. It is observed that the narrow groove GMA weld joint shows significant variation of weld metal chemistry compared to the conventional V-groove GMA weld joint since the dilution of base metal extends from the deposit adjacent to groove wall to weld center through dissolution by fusion and solid state diffusion. Further, it is noticed that a high rate of metal deposition along with high velocity of droplet transfer in P-GMAW process enhances the dilution of weld deposit and accordingly varies the chemical composition in multi-pass P-GMA weld deposit. Lower angle of attack to the groove wall surface along with low heat input in NG-13 weld groove minimizes the effect of dissolution by fusion and solid state diffusion from the deposit adjacent to groove wall to weld center. This results in more uniform properties of NG-13 P-GMA weld in comparison to those of NG-20 and CG welds.

  17. Contribution For Arc Temperature Affected By Current Increment Ratio At Peak Current In Pulsed Arc

    Science.gov (United States)

    Kano, Ryota; Mitubori, Hironori; Iwao, Toru

    2015-11-01

    Tungsten Inert Gas (TIG) Welding is one of the high quality welding. However, parameters of the pulsed arc welding are many and complicated. if the welding parameters are not appropriate, the welding pool shape becomes wide and shallow.the convection of driving force contributes to the welding pool shape. However, in the case of changing current waveform as the pulse high frequency TIG welding, the arc temperature does not follow the change of the current. Other result of the calculation, in particular, the arc temperature at the reaching time of peak current is based on these considerations. Thus, the accurate measurement of the temperature at the time is required. Therefore, the objective of this research is the elucidation of contribution for arc temperature affected by current increment ratio at peak current in pulsed arc. It should obtain a detail knowledge of the welding model in pulsed arc. The temperature in the case of increment of the peak current from the base current is measured by using spectroscopy. As a result, when the arc current increases from 100 A to 150 A at 120 ms, the transient response of the temperature didn't occur during increasing current. Thus, during the current rise, it has been verified by measuring. Therefore, the contribution for arc temperature affected by current increment ratio at peak current in pulsed arc was elucidated in order to obtain more knowledge of welding model of pulsed arc.

  18. AZ31B镁合金薄板的钨极氩弧焊组织与性能研究%Microstructure and Properties of Argon Tungsten Arc Welding Joints of AZ31 B Magnesium Alloy Plates

    Institute of Scientific and Technical Information of China (English)

    杜双明; 杨亮

    2011-01-01

    The technical characteristics of argon tungsten arc welding for AZ31B magnesium alloy plates with 2 mm thickness were discussed. The microstructure, phase composition, mechanical properties and fracture morphology of welding joints were investigated using metalloscope, X-ray diffractometer, universal tensile testing machine and scanning electron microscopy. The results show that, at 50 A welding currents, the welded joint can get good weld formation and high welding quality, with no pore and crack inside. The tensile strength of the welded joint gets to 210 Mpa, which is about 87% of the base materials. Fractures occurring in weld zones are ductile-brittle fractures. The microstnicture is fine equiaxed grain in welded zone, which mainly consists of ct-Mg and Mg17Al12. The microstructure of heat affected zones is coarser. The results of hardness test show that the hardness of the weld zone is higher than the base materials.%探讨了2mm厚的AZ31B镁合金钨极交流氩弧焊焊接的工艺特点,利用金相显微镜、X射线衍射仪、万能拉伸试验机、扫描电子显微镜等手段对焊接接头显微组织、焊缝相组成、接头力学性能、断口形貌特征等进行了分析.结果表明:焊接电流为50A时,外观成型良好,焊缝质量高,内部几乎无气孔和裂纹等缺陷,焊接接头的抗拉强度达到210 MPa,约为母材强度的87%,断裂发生在焊缝区,表现为韧-脆混合断裂.焊缝区组织呈细小的等轴晶,主要存在α-Mg和Mg17A112两种相,热影响区组织较粗大.硬度测试结果显示,焊缝区域的硬度高于母材.

  19. Modélisation du procédé de soudage hybride Arc / Laser par une approche level set application aux toles d'aciers de fortes épaisseurs A level-set approach for the modelling of hybrid arc/laser welding process application for high thickness steel sheets joining

    Directory of Open Access Journals (Sweden)

    Desmaison Olivier

    2013-11-01

    Full Text Available Le procédé de soudage hybride Arc/Laser est une solution aux assemblages difficiles de tôles de fortes épaisseurs. Ce procédé innovant associe deux sources de chaleur : un arc électrique produit par une torche MIG et une source laser placée en amont. Ce couplage améliore le rendement du procédé, la qualité du cordon et les déformations finales. La modélisation de ce procédé par une approche Level Set permet une prédiction du développement du cordon et du champ de température associé. La simulation du soudage multi-passes d'une nuance d'acier 18MnNiMo5 est présentée ici et les résultats sont comparés aux observations expérimentales. The hybrid arc/laser welding process has been developed in order to overcome the difficulties encountered for joining high thickness steel sheets. This innovative process gathers two heat sources: an arc source developed by a MIG torch and a pre-located laser source. This coupling improves the efficiency of the process, the weld bead quality and the final deformations. The Level-Set approach for the modelling of this process enables the prediction of the weld bead development and the temperature field evolution. The simulation of the multi-passes welding of a 18MnNiMo5 steel grade is detailed and the results are compared to the experimental observations.

  20. Study of modeling and simulation of full digital controlled PMIG/MAG welding system based on Matlab/Simulink

    Institute of Scientific and Technical Information of China (English)

    王伟明; 刘嘉; 苏建中; 殷树言; 马德

    2004-01-01

    This paper presents an integrated simulation model for full digital controlled PMIG/MAG welding system with Matlab/Simulink, and it consists of power inverter, digital control system and dynamic arc-load model. An integrated simulation study was done for full digital PMIG/MAG welding, and a method of connecting dynamic arc-load model to the system with controlled current source was presented, in addition, the simulation results were utilized to study the issues of digital control PMIG/MAG welding in this paper. The experimental results validated the developed simulation model, and this simulation study can be applied in implementation of the full digital PMIG/MAG welding and analysis of system dynamic process.

  1. 混合保护气体成分对不锈钢气保焊焊缝成形的影响%The Influence of Composition of Mixed Shielding Gas on the Weld Appearance of Stainless Steel Gas Shield Arc Welding

    Institute of Scientific and Technical Information of China (English)

    王博

    2012-01-01

    This paper studies the effect of difference of shielding gas composition and proportion of stainless steel melting pole gas shield arc welding on weld appearance, analyzes the advantages and disadvantages of different gases, in order to provide a strong basis for rationally using shielding gas composition and accessing good weld.%本文研究不锈钢熔化极气保焊保护气体成分与比例不同对焊缝成形的影响,分析了不同气体的优缺点,为合理选用保护气体成分、获得优良的焊缝成形提供了有力的依据.

  2. Construction and final assembly of an automatic arc welding machine; Construccion y puesta a punto de una maquina automatica para soldadura remota por arco bajo atmosfera inerte

    Energy Technology Data Exchange (ETDEWEB)

    Herrero Alvarez, J.; Diaz Diaz, J.; Diaz Diaz, J. L.

    1972-07-01

    It has been constructed a remote are welding machine, wholly transistorized, to be used in a Hot Cell of 1.000 Cu. In this work are presented the different parts of the equipment and its electronic description. Finally, some works of final preparation are shown such as ending of irradiation capsules, thermocouples welding, stainless steel cover welding. For these types of welding are quoted its relative programs. (Author)

  3. 'GAIM' - Gas-addition, impedance-matched arc driver. [shock tube gas dynamics

    Science.gov (United States)

    Dannenberg, R. E.

    1980-01-01

    A conceptual view for a GAIM energy/driver system to maximize shock-tube performance through efficient interfacing of the energy source with the gas dynamics of the arc driver is presented. Electrical and arc-chamber requirements are evaluated utilizing two new computer codes. One code calculates the shock wave generated for a selected time rate and magnitude of arc-energy input; the other computes the values of external circuit elements required to produce the selected energy input, with the driver represented as the load element of the electrical discharge circuit. Results indicate that the energy-storage capability and the driver arrangement needed to produce the highest shock Mach number can be achieved by means of driver gas addition and by impedance matching (GAIM). Design criteria are presented for arc energy requirements necessary to produce given shock-wave speeds. Shock velocities as high as the 70 km/sec required for simulating Jovian entry now seem possible in shock-tube operation. Practical implementation of a GAIM system is discussed.

  4. Preparation of carbon nanoparticles by plasma arc discharge under fluidized dynamic equilibrium

    Science.gov (United States)

    Wang, F.; Sun, D. L.; Hong, R. Y.; Kumar, M. R.

    2016-06-01

    Continuous preparation of carbon nanoparticles by dielectric barrier discharge (DBD)-induced non-thermal plasma arc discharge with large spacing in a modified fluidized bed is presented. Discharge arc is generated via the inducement of DBD which provides conductive media in order to realize a large spacing arc discharge. Three kinds of flow conditions defined as full circulation, fluidized dynamic equilibrium, and full collection are determined by the relationship of critical fluidized velocity and the real gas velocity after some modification of the fluidized bed. Movement model of carbon nanoparticles has been proposed to illustrate the flow conditions. A visualized and comprehensive refinement of aggregating processes has been exhibited and proved by high-resolution transmission electron microscopy. Simplified equivalent electrical conductive model of the arc discharge system is successful to generally and perspicuously figure out the discharge process which is impeded by the generated carbon nanoparticles. Effects of flow conditions and flow ratio of carrier gas/carbon source on morphology and yield of nanoparticles have been analyzed by morphology observation and yield calculation along with modeling the process.

  5. An Alternative Frictional Boundary Condition for Computational Fluid Dynamics Simulation of Friction Stir Welding

    Science.gov (United States)

    Chen, Gaoqiang; Feng, Zhili; Zhu, Yucan; Shi, Qingyu

    2016-09-01

    For better application of numerical simulation in optimization and design of friction stir welding (FSW), this paper presents a new frictional boundary condition at the tool/workpiece interface for computational fluid dynamics (CFD) modeling of FSW. The proposed boundary condition is based on an implementation of the Coulomb friction model. Using the new boundary condition, the CFD simulation yields non-uniform distribution of contact state over the tool/workpiece interface, as validated by the experimental weld macrostructure. It is found that interfacial sticking state is present over large area at the tool-workpiece interface, while significant interfacial sliding occurs at the shoulder periphery, the lower part of pin side, and the periphery of pin bottom. Due to the interfacial sticking, a rotating flow zone is found under the shoulder, in which fast circular motion occurs. The diameter of the rotating flow zone is smaller than the shoulder diameter, which is attributed to the presence of the interfacial sliding at the shoulder periphery. For the simulated welding condition, the heat generation due to friction and plastic deformation makes up 54.4 and 45.6% of the total heat generation rate, respectively. The simulated temperature field is validated by the good agreement to the experimental measurements.

  6. Molten pool surface height measurement proj ection system of small current tungsten electrode argon arc welding%小电流钨极氩弧焊熔池表面高度测量投影系统

    Institute of Scientific and Technical Information of China (English)

    范定环; 魏昇; 刘南生

    2013-01-01

    The molten pool deformed grating stripe with enough quantity and good modulation degree was demand when we measured the molten pool surface by Fourier transform profilometry.The area of tung-sten electrode argon arc welding molten pool is small and reflecting property of liquid metal surface is com-plexity that company with strong electric arc interference.The proj ection system with good performance had designed by the overall consideration about the relationship of grating pitch,molten pool surface reflec-tion,arc interference and optical system parameters.Our study had demonstrated that the molten pool con-cussion had caused the dynamic change of normal direction of liquid metal tiny surface element that has the scattering effect on light beam.Therefore,the molten pool images can be captured by use of surface scatter-ing randomly of specular reflection light.The rectangular raster with pitch of 0.4 mm had projected on welding pool surface out of focus with angle of 30 degree.The obtained deformed laser stripes had pro-cessed by computer to acquire pool surface height preliminary.%利用傅里叶变换轮廓术的基本原理测量小电流钨极氩弧焊熔池表面高度,需要获得数量足够,调制度好的熔池变形光栅条纹。钨极氩弧焊熔池面积小,液态金属表面反射性能复杂,有强烈电弧光干扰,要综合考虑光栅节距、熔池表面反射、弧光干扰与光学系统参数之间的关系,设计好投影系统。研究表明,小电流钨极氩弧焊熔池振荡造成液态金属表面各微面元法线方向动态变化,对光束有散射效应,对于投射的结构光束,可以通过随机表面散射的镜面反射光拍摄熔池图像。将节距为0.4 mm的矩形光栅以30°左右的掠射角离焦投射到钨极氩弧焊熔池表面,可获得较好的熔池变形光栅条纹,经后续处理,可初步测量出熔池表面高度。

  7. Characterization of Low Temperature Ferrite/Austenite Transformations in the Heat Affected Zone of 2205 Duplex Stainless Steel Arc Welds

    Energy Technology Data Exchange (ETDEWEB)

    Palmer, T A; Elmer, J W; Babu, S S; Vitek, J M

    2003-08-20

    Spatially Resolved X-Ray Diffraction (SRXRD) has been used to identify a previously unobserved low temperature ferrite ({delta})/austenite({gamma}) phase transformation in the heat affected zone (HAZ) of 2205 Duplex Stainless Steel (DSS) welds. In this ''ferrite dip'' transformation, the ferrite transforms to austenite during heating to peak temperatures on the order of 750 C, and re-transforms to ferrite during cooling, resulting in a ferrite volume fraction equivalent to that in the base metal. Time Resolved X-Ray Diffraction (TRXRD) and laser dilatometry measurements during Gleeble{reg_sign} thermal simulations are performed in order to verify the existence of this low temperature phase transformation. Thermodynamic and kinetic models for phase transformations, including both local-equilibrium and para-equilibrium diffusion controlled growth, show that diffusion of substitutional alloying elements does not provide a reasonable explanation for the experimental observations. On the other hand, the diffusion of interstitial alloying elements may be rapid enough to explain this behavior. Based on both the experimental and modeling results, two mechanisms for the ''ferrite dip'' transformation, including the formation and decomposition of secondary austenite and an athermal martensitic-type transformation of ferrite to austenite, are considered.

  8. Effects of shielding gas on weld shape and arc characteristic in laser+twin-electrode MAG hybrid welding%保护气体对激光+双丝MAG复合焊焊缝形貌和电弧特性的影响

    Institute of Scientific and Technical Information of China (English)

    李明利

    2012-01-01

    在激光+单电弧复合焊工艺的基础上,通过再添加一个电孤的方式,形成激光+双丝脉冲MAG复合焊工艺.研究了保护气体为φ(Ar)80%+φ(CO2)20%(情况A)和φ(Ar)40%+φ(CO2)10%+φ(He)50%(情况B)时对激光+双丝MAG复合焊焊缝表面成形和电弧特性的影响.利用LabVIEW信号采集系统和高速摄像系统同步采集焊接电流、电孤电压波形和电弧形态.结果表明,在焊缝表面和焊道两侧边缘处,肉眼可见斑点状、不连续的氧化物,情况A与情况B相比,情况A氧化物含量高,熔宽小;而情况B焊道平整,鱼鳞纹清晰.情况A中由于CO2含量较高,使其对电弧的冷却作用增强,减弱了激光对电弧的稳定作用,断弧次数比情况B多.%Based on laser+single are welding,the laser-rtwin-electiode MAG hybrid welding is developed by adding the other arc.With the shielding gas of y (Ar)80%+φ(CO2)20%(condition A) and φ(Ar)40%+φ(He)50%+φ(CO2)10%(condition B),the effects of the varying ratio of C02 on weld shape and arc characteristic are studied in laser+twin-electrode MAG hybrid welding.The LabVIEW signal acquisition system and high-speed photography system are used to monitor welding current,arc voltage and arc behavior.The results show that spotted and discontinuous oxides are visible on the surface and both sides of the weld.Compared condition A with condition B,the oxides content under condition A is high and the weld width is small.Then under condition B,the weld is smooth and scaly figure is distinct.Due to the high CO; ratio in condition A.the effect of cooling arcs is enhanced and the effect of stabilizing arcs is weakened.The arc interruption times under condition A is more than under condition B.

  9. Image processing of ESPI based on measurement the welding dynamic displacement fields

    Institute of Scientific and Technical Information of China (English)

    陶军; 李冬青; 范成磊; 刘忠国

    2004-01-01

    A dual-beam electronic speckle pattern interferometry (ESPI) system was adopted to get speckle patterns for the measurement of welding dynamic displacement fields. The mathematical model of this system was described, based on which methods of the ESPI pattern image processing were discussed. Gray transformation and histogram equalization were used to enhance the contrast of speckle patterns. A discrete cosine image processing method was carried out and an exponent low-pass filter was chosen to reduce multiplicative noise in speckle patterns. Speckle grain noise can be eliminated effectively after these processes.

  10. Lung tumor production and tissue metal distribution after exposure to manual metal ARC-stainless steel welding fume in A/J and C57BL/6J mice.

    Science.gov (United States)

    Zeidler-Erdely, Patti C; Battelli, Lori A; Salmen-Muniz, Rebecca; Li, Zheng; Erdely, Aaron; Kashon, Michael L; Simeonova, Petia P; Antonini, James M

    2011-01-01

    Stainless steel welding produces fumes that contain carcinogenic metals. Therefore, welders may be at risk for the development of lung cancer, but animal data are inadequate in this regard. Our main objective was to examine lung tumor production and histopathological alterations in lung-tumor-susceptible (A/J) and -resistant C57BL/6J (B6) mice exposed to manual metal arc-stainless steel (MMA-SS) welding fume. Male mice were exposed to vehicle or MMA-SS welding fume (20 mg/kg) by pharyngeal aspiration once per month for 4 mo. At 78 wk postexposure, gross tumor counts and histopathological changes were assessed and metal analysis was done on extrapulmonary tissue (aorta, heart, kidney, and liver). At 78 wk postexposure, gross lung tumor multiplicity and incidence were unremarkable in mice exposed to MMA-SS welding fume. Histopathology revealed that only the exposed A/J mice contained minimal amounts of MMA-SS welding fume in the lung and statistically increased lymphoid infiltrates and alveolar macrophages. A significant increase in tumor multiplicity in the A/J strain was observed at 78 wk. Metal analysis of extrapulmonary tissue showed that only the MMA-SS-exposed A/J mice had elevated levels of Cr, Cu, Mn, and Zn in kidney and Cr in liver. In conclusion, this study further supports that MMA-SS welding fume does not produce a significant tumorigenic response in an animal model, but may induce a chronic lung immune response. In addition, long-term extrapulmonary tissue alterations in metals in the susceptible A/J mouse suggest that the adverse effects of this fume might be cumulative.

  11. Evolution of a Laser Hybrid Welding Map

    Science.gov (United States)

    Kaplan, Alexander F. H.; Frostevarg, Jan; Ilar, Torbjörn; Bang, Hee-Seon; Bang, Han-Sur

    Laser arc hybrid welding combines the advantages but also the complex physical mechanisms of gas metal arc welding and laser keyhole welding. From manifold mainly experimental but also theoretical research results a map with versatile functions was initiated for the first time. The purpose is to survey the overall context and to facilitate navigation to the various phenomena that are shown through case studies accompanied by theoretical explanations and guidelines for optimization. Though not complete, the map enables systematic and graphical navigation to relevant publications. Based on a fundamental structure of the map, which was decided early, it is inherently extendable in the future by adding existing and new knowledge, also from other research groups, enabling evolution. The fundament of the map structure comprises gouge thickness, joint type and metal grade, in coherence with product and weld designers' starting points. The next hierarchy level of the map offers options in the joint type as well as in hybrid welding techniques. The latter contains techniques like double-sided welding, pulse shaping management of the arc or laser, CMT arcs, tandem arcs, or remelting of undercuts. In addition to laser-arc hybrid welding, other hybrid laser techniques like multilayer hot-wire laser welding of narrow gaps or hybrid laser friction stir welding can be taken into account. At the other end of the hierarchy, the map offers via a database-like archive electronic navigation to research results like weld macrographs, high speed imaging or numerical simulation results of the welding process.

  12. The Dynamics and Sliding Mode Control of Multiple Cooperative Welding Robot Manipulators

    Directory of Open Access Journals (Sweden)

    Bin Zi

    2012-08-01

    Full Text Available This paper deals with the design, dynamic modelling and sliding mode control of multiple cooperative welding robot manipulators (MWRMs. The MWRMs can handle complex tasks that are difficult or even impossible for a single manipulator. The kinematics and dynamics of the MWRMs are studied on the basis of the Denavit‐Hartenberg and Lagrange method. Following that, considering the MWRM system with nonlinear and unknown disturbances, a non‐singular terminal sliding mode control strategy is designed. By means of the Lyapunov function, the stability of the controller is proved. Simulation results indicate that the good control performance of the MWRMs is achieved by the non‐singular terminal sliding mode controller, which also illustrates the correctness of the dynamic modelling and effectiveness of the proposed control strategy.

  13. Evaluation on Fracture Toughness at Dynamic Loading for Welded Joint Based on the Local Approach

    Institute of Scientific and Technical Information of China (English)

    Hongyang JING; Lianyong XU; Lixing HUO; Yufeng ZHANG

    2004-01-01

    The changes in mechanical properties and fracture toughness by dynamic loading were investigated with experiments.The parameter R, which can reflect the effect of the loading rate and the temperature rising during the high loading rate, could be employed to describe the constituent relation for the typical structure steel and its weld metal. The dynamic loading effect on the stress/strain fields and the temperature variation in the vicinity of the crack tip was analyzed by the finite element method, the dynamic fracture behavior was evaluated based on the local approach. It has been found that the Weibull stress is an effective fracture parameter, independent of the temperature and the loading rate.

  14. CO2气体保护焊在水工钢结构制造中的工艺应用%The application of the CO2 gas shielded arc welding in hydraulic steel structures

    Institute of Scientific and Technical Information of China (English)

    方仕庆; 曹振锋

    2012-01-01

    CO2气体保护焊技术已大量的应用于水工钢结构施工工艺中,其具有焊接速度快、效率高、成型好和变形小的突出特点。本篇主要介绍的是CO2气体保护焊在水工钢结构施工中焊材的选用、焊接工艺、实际操作等应用方面的问题。%CO2 gas shielded arc welding technology have been widely used in hydraulic steel structure construction,which has special advantages of the welding speed fast,high efficiency,easy forming and small deformation.This paper describes the selection,welding process,and practical application aspects of CO2 gas shielded welding in the construction of hydraulic steel structures.

  15. Improvement in Fatigue Performance of Aluminium Alloy Welded Joints by Laser Shock Peening in a Dynamic Strain Aging Temperature Regime

    Directory of Open Access Journals (Sweden)

    Chun Su

    2016-09-01

    Full Text Available As a new treatment process after welding, the process parameters of laser shock peening (LSP in dynamic strain aging (DSA temperature regimes can be precisely controlled, and the process is a non-contact one. The effects of LSP at elevated temperatures on the distribution of the surface residual stress of AA6061-T6 welded joints were investigated by using X-ray diffraction technology with the sin2ϕ method and Abaqus software. The fatigue life of the welded joints was estimated by performing tensile fatigue tests. The microstructural evolution in surface and fatigue fractures of the welded joints was presented by means of surface integrity and fracture surface testing. In the DSA temperature regime of AA6061-T6 welded joints, the residual compressive stress was distributed more stably than that of LSP at room temperature. The thermal corrosion resistance and fatigue properties of the welded joints were also improved. The experimental results and numerical analysis were in mutual agreement.

  16. Single arc volumetric-modulated arc therapy is sufficient for nasopharyngeal carcinoma: a dosimetric comparison with dual arc VMAT and dynamic MLC and step-and-shoot intensity-modulated radiotherapy

    OpenAIRE

    NING, ZHONG-HUA; Mu, Jin-Ming; Jin, Jian-Xue; Li, Xiao-Dong; LI, QI-LIN; GU, WEN-DONG; Huang, Jin; Han, Yang; PEI, HONG-LEI

    2013-01-01

    Background The performance of single arc VMAT (VMAT1) for nasopharyngeal carcinoma (NPC) on the Axesse linac has not been well described in previous studies. The purpose of this study is to assess the feasibility of VMAT1 for NPC by comparing the dosimetry, delivery efficiency, and accuracy with dual arc VMAT (VMAT2), dynamic MLC intensity-modulated radiotherapy (dIMRT), and step-and-shoot intensity-modulated radiotherapy (ssIMRT). Methods Twenty consecutive patients with non-metastatic NPC w...

  17. Dosimetry Comparison between Volumetric Modulated Arc Therapy with RapidArc and Fixed Field Dynamic IMRT for Local-Regionally Advanced Nasopharyngeal Carcinoma

    Institute of Scientific and Technical Information of China (English)

    Bao-min Zheng; Xiao-xia Dong; Hao Wu; You-jia Duan; Shu-kui Han; Yan Sun

    2011-01-01

    Objective:A dosimetric study was performed to evaluate the performance of volumetric modulated arc radiotherapy with RapidArc on locally advanced nasopharyngeal carcinoma (NPC).Methods:The CT scan data sets of 20 patients of locally advanced NPC were selected randomly.The plans were managed using volumetric modulated arc with RapidArc and fixed nine-field coplanar dynamic intensity-modulated radiotherapy (IMRT) for these patients.The dosimetry of the planning target volumes (PTV),the organs at risk (OARs) and the healthy tissue were evaluated.The dose prescription was set to 70 Gy to the primary tumor and 60 Gy to the clinical target volumes (CTV) in 33 fractions.Each fraction applied daily,five fractions per week.The monitor unit (MU) values and the delivery time were scored to evaluate the expected treatment efficiency.Results:Both techniques had reached clinical treatment's requirement.The mean dose (Dmean),maximum dose (Dmax) and minimum dose (Dmin) in RapidArc and fixed field IMRT for PTV were 68.4±0.6 Gy,74.8±0.9 Gy and 56.8±1.1 Gy; and 67.6±0.6 Gy,73.8±0.4 Gy and 57.5±0.6 Gy (P<0.05),respectively.Homogeneity index was 78.85±1.29 in RapidArc and 80.34±0.54 (P<0.05) in IMRT.The conformity index (CI:95%) was 0.78±0.01 for both techniques (P>0.05).Compared to IMRT,RapidArc allowed a reduction of Dmean to the brain stem,mandible and optic nerves of 14.1% (P<0.05),5.6% (P<0.05) and 12.2% (P<0.05),respectively.For the healthy tissue and the whole absorbed dose,Dmean of RapidArc was reduced by 3.6% (P<0.05),and 3.7% (P<0.05),respectively.The Dmean to the parotids,the spinal cord and the lens had no statistical difference among them.The mean MU values of RapidArc and IMRT were 550 and 1,379.The mean treatment time of RapidArc and IMRT was 165 s and 447 s.Compared to IMRT,the delivery time and the MU values of RapidArc were reduced by 63% and 60%,respectively.Conclusion:For locally advanced NPC,both RapidArc and IMRT reached

  18. Effects of Surface Alloying and Laser Beam Treatment on the Microstructure and Wear Behaviour of Surfaces Modified Using Submerged Metal Arc Welding

    Directory of Open Access Journals (Sweden)

    Regita BENDIKIENE

    2016-05-01

    Full Text Available In this study, the effects of surface alloying of cheap plain carbon steel using submerged metal arc technique and subsequent laser beam treatment on the microstructure and wear behaviour of surfaced layers were studied. This method is the cheapest one to obtain high alloyed coatings, because there is no need to apply complex technologies of powder making (metal powder is spread on the surface of base metal or inserted into the flux, it is enough to grind, granulate and blend additional materials. On the other hand, strengthening of superficial layers of alloys by thermal laser radiation is one of the applications of laser. Surface is strengthened by concentrated laser beam focused into teeny area (from section of mm till some mm. Teeny area of metal heat up rapidly and when heat is drain to the inner metal layers giving strengthening effect. Steel surface during this treatment exceeds critical temperatures, if there is a need to strengthen deeper portions of the base metal it is possible even to fuse superficial layer. The results presented in this paper are based on micro-structural and micro-chemical analyses of the surfaced and laser beam treated surfaces and are supported by analyses of the hardness, the wear resistance and resultant microstructures. Due to the usage of waste raw materials a significant improvement (~ 30 % in wear resistance was achieved. The maximum achieved hardness of surfaced layer was 62 HRC, it can be compared with high alloyed conventional steel grade. Wear properties of overlays with additional laser beam treatment showed that weight loss of these layers was ~10 % lower compared with overlays after welding; consequently it is possible to replace high alloyed conventional steel grades forming new surfaces or restoring worn machine elements and tools.DOI: http://dx.doi.org/10.5755/j01.ms.22.1.7621

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

    Energy Technology Data Exchange (ETDEWEB)

    Hardt, D.E.; Masubuchi, K.; Paynter, H.M.; Unkel, W.C.

    1983-04-01

    Closed-loop control of the welding variables represents a promising, cost-effective approach to improving weld quality and therefore reducing the total cost of producing welded structures. The ultimate goal is to place all significant weld variables under direct closed-loop control; this contrasts with preprogrammed machines which place the welding equipment under control. As the first step, an overall strategy has been formulated and an investigation of weld pool geometry control for gas tungsten arc process has been completed. The research activities were divided into the areas of arc phenomena, weld pool phenomena, sensing techniques and control activities.

  20. Arc Spectrum Diagnostic and Heat Coupling Mechanism Analysis of Double Wire Pulsed MIG Welding%双丝脉冲MIG焊接电弧光谱诊断及热源耦合机理分析

    Institute of Scientific and Technical Information of China (English)

    刘永强; 李桓; 杨立军; 郑凯; 高莹

    2015-01-01

    A double wire pulsed MIG welding test system was built in the present paper ,in order to analyze the heat-coupling mechanism of double wire pulsed MIG welding ,and study arc temperature field .Spectroscopic technique was used in diagnostic analysis of the arc ,plasma radiation was collected by using hollow probe method to obtain the arc plasma optical signal .The electron temperature of double wire pulsed MIG welding arc plasma was calculated by using Boltzmann diagram method ,the electron temperature distribution was obtained ,a comprehensive analysis of the arc was conducted combined with the high speed camera technology and acquisition means of electricity signal .The innovation of this paper is the combination of high-speed cam-era image information of arc and optical signal of arc plasma to analyze the coupling mechanism for dual arc ,and a more intuitive analysis for arc temperature field was conducted .The test results showed that a push-pull output was achieved and droplet trans-fer mode was a drop in a pulse in the welding process ;Two arcs attracted each other under the action of a magnetic field ,and shifted to the center of the arc in welding process ,so a new heat center was formed at the geometric center of the double arc ,and flowing up phenomenon occurred on the arc ;Dual arc electronic temperature showed an inverted V-shaped distribution overall , and at the geometric center of the double arc ,the arc electron temperature at 3 mm off the workpiece surface was the highest , which was 16 887.66 K ,about 4 900 K higher than the lowest temperature 11 963.63 K .%搭建了双丝脉冲M IG焊接试验系统,为了分析研究双丝脉冲M IG焊接的热源耦合机理以及电弧温度场,采用光谱技术对其电弧进行了诊断分析,采用中空探针法进行等离子体的辐射采集,得到电弧等离子体的光信号,利用Boltzmann图法计算了双丝脉冲M IG焊接电弧等离子体的电子温度,得出了电弧等离子体