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Sample records for welding research supplement

  1. Welding.

    Science.gov (United States)

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    This curriculum guide is designed for use by South Carolina vocational education teachers as a continuing set of lesson plans for a two-year course on welding. Covered in the individual sections of the guide are the following topics: an orientation to welding, oxyacetylene welding, advanced oxyacetylene welding, shielded metal arc welding, TIG…

  2. Research Progress in Friction Welding of Magnesium Alloy

    Directory of Open Access Journals (Sweden)

    YOU Guo-qiang

    2018-01-01

    Full Text Available The basic principles and features of friction welding were introduced.The research progresses in friction welding of Mg alloys were reviewed. The process, joining mechanism, microstructure and mechanical properties of Mg-Mg similar and Mg-Al dissimilar friction welded joints were primarily discussed. Meanwhile, the current problems were analyzed. It was pointed out that the temperature field, stress-strain field and plastic flow during the friction welding process of Mg alloys require further investigation. Furthermore, the future development should focus on the optimization of process and intermediate layer to obtain high quality joints.

  3. Research of the Resistance of Contact Welding Joint of R65 Type Rail

    Directory of Open Access Journals (Sweden)

    Kęstutis Dauskurdis

    2015-03-01

    Full Text Available In the article the R65 type rail joints that were welded by resistance welding are analysed. Survey methodology of the research consists of the following parts: visual inspection of welded joint, ultrasonic rail inspection, hardness test of upper part of the rail, fusion area research, the measurement hardness test of heat-softened area, the measurement microhardness test, microstructure research of the welded joint, impact strength experiments, chemical analysis of welded joint, wheel-rail interaction research using the finite element method (FEM. The results of the research are analysed and the quality of weld is evaluated. The conclusion is based on the results of this research.

  4. Development of New Materials and Technologies for Welding and Surfacing at Research and Production Center "Welding Processes and Technologies"

    Science.gov (United States)

    Kozyrev, N. A.; Kryukov, R. E.; Galevsky, G. V.; Titov, D. A.; Shurupov, V. M.

    2015-09-01

    The paper provides description of research into the influence of new materials and technologies on quality parameters of welds and added metal carried out at research and production center «Welding processes and technologies». New welding technologies of tanks for northern conditions are considered, as well as technologies of submerged arc welding involving fluxing agents AN - 348, AN - 60, AN - 67, OK. 10.71 and carbon-fluorine containing additives, new flux cored wires and surfacing technologies, teaching programs and a trainer for welders are designed.

  5. Research on stress corrosion behavior of CCSE40 welded by underwater wet welding with austenitic welding rod in seawater

    Science.gov (United States)

    Zou, Y.; Bai, Q.; Dong, S.; Yang, Z. L.; Gao, Y.

    2017-09-01

    The stress corrosion behavior of CCSE40 welded by underwater wet welding with austenitic welding rod in seawater was studied. Microstructure, mechanical property and stress corrosion cracking susceptibility of the underwater wet welding joint were analyzed by metallographic observation, tensile and bending tests, slow strain rate test (SSRT) and SEM. The results indicated that the weld zone (WZ) and the heat affected zone (HAZ) were all sensitive to the stress corrosion, and the WZ was more sensitive than the HAZ.

  6. 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.

  7. Research Activities at IPT, DTU on Resistance Projection Welding

    DEFF Research Database (Denmark)

    Bay, Niels

    2000-01-01

    Resistance welding processes and among these especially the resistance projection welding is considered an industrially strategic process with increasing applications as alternative to other welding processes, soldering, brazing and mechanical assembling. This is due to increasing requirements...

  8. Research Progress in Plasma arc welding of Magnesium Alloys and Magnesium Matrix Composites

    Science.gov (United States)

    Hui, Li; Yang, Zou; Yongbo, Li; Lei, Jiao; Ruijun, Hou

    2017-11-01

    Magnesium alloys and magnesium matrix composites by means of its excellent performance have wide application prospect in electronics, automotive, biotechnology, aerospace field, and welding technology has become a key of restricting its application. This paper describes the welding characteristics of magnesium, the obvious advantages in the application and the domestic and foreign research advance technology of plasma arc welding of magnesium, and summarizes the existing problems and development trends of plasma arc welding technology of magnesium.

  9. Lasers in car body construction - substitution of conventional welding techniques or supplement

    Energy Technology Data Exchange (ETDEWEB)

    Imhoff, R.; Behler, K.; Beyer, E.

    1988-09-01

    In car body construction, laser beam welding competes with resistance spot welding and with projection welding. There are problems concerning the short bridging distance of the laser beam welding, but there are also some advantages, i.e.: lower weight; higher strength and stiffness of the car body; high welding speed (5 to 10 m/min); triple-pass welding; welding at a present depth for attaching reinforcing elements on the inside of visible car parts for the purpose of vibration and noise damping; good process control characteristics. In the long run, laser beam welding is expected to replace conventional welding techniques in car body construction.

  10. 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…

  11. Research on the Effects of Technical Parameters on the Molding of the Weld by A-TIG Welding

    OpenAIRE

    Shi, Kai; Pan, Wu

    2012-01-01

    The effects of welding parameters on the molding of weld by A-TIG welding of a 4mm thickness mild steel plate is studied in the present paper. The results obtained show that: as welding current increases A-TIG welding penetration gets deeper than TIG welding; size and shape of HAZ has remarkable change; A-TIG welding has the narrower weld pool width than TIG welding.

  12. The National Shipbuilding Research Program. Square Butt Pipe Welding

    National Research Council Canada - National Science Library

    Langhelm, J; Scheltens, James

    1996-01-01

    .... X-ray quality full penetration square butt weld joints were expected. Significant cost savings can be achieved through the reduction in pipe fitting and welding man-hours by utilization of a saw cut square butt joint design...

  13. Research on Fracture Failure of the Underwater Welding Joint

    Science.gov (United States)

    Kong, Xiangfeng; Qiu, Feng; Zhang, Jing; Zou, Yan; Chu, Dongzhi

    2017-12-01

    In this paper, by testing welding joints of their metallography and hardness, we analyze the metal structure. And then, the microstructure characteristics, macro and micro fracture morphology of underwater welding joint were investigated by means of metallographical examination and SEM. The fracture failure of the underwater welding joint is discussed here. The cracks are the major factors to fracture failure. The cracks spread along with the crack of the welding line, and this expand process generates dimple. The crack continues to expand under the action of tensile and the fracture fails eventually.

  14. Research on the welding process of aluminum alloy based on high power fiber laser

    Science.gov (United States)

    Zhang, Jian; Zhang, Wei; Pan, Xiaoming; Huang, Shanshi; Liu, Wenwen

    2017-08-01

    To research the formation and variation principle of the weld seam and molten pool for aluminum alloy high power fiber laser welding, the welding experiments for 5052 aluminum alloy were carried out. The influences of laser power, scanning velocity and protection gas on the welding process were systematically researched. The results show that with the increase of power and scanning velocity, the depth to width ratio first increases and then decreases. The ratio reaches the maximum value at 2.6 KW and 30 mm/s, respectively. When the power located at 2.6 KW to 2.8 KW or the velocity located at 25 mm/s to 30 mm/s, stable deep penetration welding can be obtained. The weld seam shows relative flat appearance and the molten pool presents typical "T shape" topography. Moreover, the protection gas also influences the appearance of the weld seam. Using the independently designed fixture, the quality of the weld seam can be well improved.

  15. Research on pipe welding information management system basedon RFID

    Directory of Open Access Journals (Sweden)

    Liu Xun

    2016-01-01

    Full Text Available This paper introduces the construction background, construction target and construction principle of the pipe welding management system based on RFID. Then, describes the specific requirements of the system. The basic principle and key technology of the system are introduced. The structure of the system (including the system design, the selections of handheld devices and high frequency passive RFID tags is described .Then the system management software designs (including software structure, the main functions of the management center system and the main functions of the handheld detection system are described in detail. Finally, the management system is implemented, and it is deployed to several Gas Co, which has chieved good results.

  16. Characterizing Shipyard Welding Emissions and Associated Control Options (The National Shipbuilding Research Program)

    Science.gov (United States)

    1995-08-01

    commbination of flux and gas shielding that protect the weld from nitrogen and oxygen entrapment . Shielding wilI be discussed in the following...Documentation Center The University of Michigan Transportation Research Institute Marine Systems Division 2901 Baxter Road Ann Arbor, MI 48109-2150 Phone: 734-763-2465 Fax: 734-936-1081 E-mail: Doc.Center@umich.edu

  17. Dietary supplement research portfolio at the NIH, 2009-2011.

    Science.gov (United States)

    Garcia-Cazarin, Mary L; Wambogo, Edwina A; Regan, Karen S; Davis, Cindy D

    2014-04-01

    The U.S. dietary supplement market increased by 7.5% in 2012 compared with 2011, reaching $32.5 billion in sales. Therefore, federally supported research on dietary supplements is important to determine their health effects, safety, and efficacy. A portfolio analysis was performed across the NIH and the Office of Dietary Supplements (ODS) for fiscal years (FYs) 2009-2011 by using the databases Human Nutrition Research Information Management (HNRIM) and Computer Access to Research on Dietary Supplements (CARDS). The results indicated that total NIH dietary supplement-related funding for FYs 2009-2011 was $855 million ($295 million in 2009, $311 million in 2010, and $249 million in 2011). The institutes and centers with the highest investment in dietary supplement research were as follows: the National Heart, Lung, and Blood Institute ($135 million); the National Cancer Institute ($188 million); the National Center for Complementary and Alternative Medicine ($99 million); the National Institute of Diabetes and Digestive and Kidney Diseases ($68 million); the National Institute of Environmental Health Sciences ($58 million); and the ODS ($32 million). The dietary supplement ingredients receiving the most funding were botanicals (22%), vitamins (20%), lipids (14%), and minerals and trace elements (10%). The top 3 outcome research areas were cancer (61% of total dietary supplement investment), cardiovascular disease (47%), and women's reproductive health (38%). In FYs 2009, 2010, and 2011, the ODS provided 3.5%, 3.6%, and 4.1%, respectively, of the NIH investment in dietary supplement research. ODS funding focused on cellular, enzymatic, or molecular mechanisms (64% of total ODS funding). This portfolio analysis demonstrates that the NIH has committed substantial funding to dietary supplement research in an effort to expand the scientific knowledge base on the efficacy and safety of dietary supplements.

  18. effect of post-weld heat treatment on the microstructure

    African Journals Online (AJOL)

    user

    among others are shielded metal arc welding, submerge arc welding, gas metal arc welding, plasma arc welding, gas ... welding (SMAW) technique is preferable to the other techniques ..... studies''International Journal of Innovative Research.

  19. Modern Methods of Rail Welding

    Science.gov (United States)

    Kozyrev, Nikolay A.; Kozyreva, Olga A.; Usoltsev, Aleksander A.; Kryukov, Roman E.; Shevchenko, Roman A.

    2017-10-01

    Existing methods of rail welding, which are enable to get continuous welded rail track, are observed in this article. Analysis of existing welding methods allows considering an issue of continuous rail track in detail. Metallurgical and welding technologies of rail welding and also process technologies reducing aftereffects of temperature exposure are important factors determining the quality and reliability of the continuous rail track. Analysis of the existing methods of rail welding enable to find the research line for solving this problem.

  20. Research on the microstructure and properties of laser-MIG hybrid welded joint of Invar alloy

    Science.gov (United States)

    Zhan, Xiaohong; Zhang, Dan; Wei, Yanhong; Wang, Yuhua

    2017-12-01

    In order to solve the problem of large deformation, low production efficiency and high tendency of hot cracking in welding 19.05 mm thick plates of Fe36Ni Invar alloy, laser-MIG hybrid multi-layer welding technique (LMHMW) has been developed. To investigate the influence of different welding parameters on the joint properties, optical microscope observation, SEM, EDS and microhardness measurement were conducted. Experimental results illustrated that different matching of welding parameters significantly affected the depth-to-width ratio, formation of defects and HAZ width. Besides, weld zone were consisted of two regions according to the different grain shape. The region near center of weld seam (region 1) was columnar dendrite induced by laser, while the region far away from weld seam center (region 2) was cellular dendrite which was mainly caused by MIG arc. The peak value of microhardness appeared at the center of weld seam since the grains in region 1 were relatively fine, and the lowest hardness value was obtained in HAZ. In addition, results showed that the sheets can be welded at optimum process parameters, with few defects such as, surface oxidation, porosity, cracks and lack of penetration in the welding seam: laser power of backing weld P = 5500 W, welding current I = 240 A, welding speed v = 1 m/min. laser power of filling weld P = 2000 W, welding current I = 220 A, welding speed v = 0.35 m/min. laser power of cosmetic weld P = 2000 W, welding current I = 300 A, welding speed v = 0.35 m/min.

  1. Research data supporting "Surface residual stresses in multipass welds produced using low transformation temperature filler alloys"

    OpenAIRE

    Ramjaun, TI; Stone, HJ; Karlsson, L.; Gharghouri, M; Dalaei, K; Moat, R.; Bhadeshia, HKDH

    2017-01-01

    Tensile residual stresses at the surface of welded components are known to compromise fatigue resistance through the accelerated initiation of microcracks, especially at the weld toe. Inducement of compression in these regions is a common technique employed to enhance fatigue performance. Transformation plasticity has been established as a viable method to generate such compressive residual stresses in steel welds and exploits the phase transformation in welding filler alloys, that transform ...

  2. Theory research of seam recognition and welding torch pose control based on machine vision

    Science.gov (United States)

    Long, Qiang; Zhai, Peng; Liu, Miao; He, Kai; Wang, Chunyang

    2017-03-01

    At present, the automation requirement of the welding become higher, so a method of the welding information extraction by vision sensor is proposed in this paper, and the simulation with the MATLAB has been conducted. Besides, in order to improve the quality of robot automatic welding, an information retrieval method for welding torch pose control by visual sensor is attempted. Considering the demands of welding technology and engineering habits, the relative coordinate systems and variables are strictly defined, and established the mathematical model of the welding pose, and verified its feasibility by using the MATLAB simulation in the paper, these works lay a foundation for the development of welding off-line programming system with high precision and quality.

  3. Research of the temperature field of welding of saddle branch to polyethylene pipe at low temperatures

    Science.gov (United States)

    Starostin, Nikolai P.; Vasileva, Maria A.; Andreev, Boris I.

    2017-11-01

    The thermal process of welding a saddle branch to a polyethylene pipe is considered with the heat of the phase transition taken into account. The corresponding three-dimensional nonlinear equation of thermal conductivity is solved by the finite element method in a complex domain. The technological operations necessary for welding the saddle branch to the polyethylene pipe at air temperatures below standard are defined based on the study of the dynamics of the temperature field during welding at various ambient temperatures.

  4. Supplement B: Research Networking Systems Characteristics Profiles. A Companion to the OCLC Research Report, Registering Researchers in Authority Files

    Science.gov (United States)

    Smith-Yoshimura, Karen; Altman, Micah; Conlon, Michael; Cristán, Ana Lupe; Dawson, Laura; Dunham, Joanne; Hickey, Thom; Hill, Amanda; Hook, Daniel; Horstmann, Wolfram; MacEwan, Andrew; Schreur, Philip; Smart, Laura; Wacker, Melanie; Woutersen, Saskia

    2014-01-01

    The OCLC Research Report, "Registering Researchers in Authority Files", [Accessible in ERIC as ED564924] summarizes the results of the research conducted by the OCLC Research Registering Researchers in Authority Files Task Group in 2012-2014. Details of this research are in supplementary data sets: (1) "Supplement A: Use Cases. A…

  5. Research on Kinematic Trajectory Simulation System of KUKA Arc Welding Robot System

    Science.gov (United States)

    Hu, Min

    2017-10-01

    In this paper, the simulation trajectory simulation of KUKA arc welding robot system is realized by means of VC platform. It is used to realize the teaching of professional training of welding robot in middle school. It provides teaching resources for the combination of work and study and integration teaching, which enriches the content of course teaching.

  6. Challenges to Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

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

  7. Metallurgical and Mechanical Research on Dissimilar Electron Beam Welding of AISI 316L and AISI 4340

    Directory of Open Access Journals (Sweden)

    A. R. Sufizadeh

    2016-01-01

    Full Text Available Dissimilar electron beam welding of 316L austenitic stainless steel and AISI 4340 low alloy high strength steel has been studied. Studies are focused on effect of beam current on weld geometry, optical and scanning electron microscopy, X-ray diffraction of the weld microstructures, and heat affected zone. The results showed that the increase of beam current led to increasing depths and widths of the welds. The optimum beam current was 2.8 mA which shows full penetration with minimum width. The cooling rates were calculated for optimum sample by measuring secondary dendrite arm space and the results show that high cooling rates lead to austenitic microstructure. Moreover, the metallography result shows the columnar and equiaxed austenitic microstructures in weld zone. A comparison of HAZ widths depicts the wider HAZ in the 316L side. The tensile tests results showed that the optimum sample fractured from base metal in AISI 316L side with the UTS values is much greater than the other samples. Moreover, the fractography study presents the weld cross sections with dimples resembling ductile fracture. The hardness results showed that the increase of the beam current led to the formation of a wide softening zone as HAZ in AISI 4340 side.

  8. Research and Science Today Supplement No. 3/2014

    Directory of Open Access Journals (Sweden)

    Zamfir-Radu IONESCU

    2014-12-01

    Full Text Available RESEARCH AND SCIENCE TODAY is a biannual science journal established in 2011. The journal is an informational platform that publishes assessment articles and the results of various scientific research carried out by academics. We provide the authors with the opportunity to create and/or perfect their science writing skills. Thus, each issue of the journal (two per year and at least two supplements will contain professional articles from any academic field, authored by domestic and international academics. The goal of this journal is to pass on relevant information to undergraduate, graduate, and post-graduate students as well as to fellow academics and researchers; the topics covered are unlimited, considering its multi-disciplinary profile. Regarding the national and international visibility of Research and Science Today, it is indexed in over 30 international databases (IDB and is present in over 200 online libraries and catalogues; therefore, anybody can easily consult the articles featured in each issue by accessing the databases or simply the website.

  9. Research and Science Today Supplement No. 1/2015

    Directory of Open Access Journals (Sweden)

    Adrian Todor

    2015-01-01

    Full Text Available RESEARCH AND SCIENCE TODAY is a biannual science journal established in 2011. The journal is an informational platform that publishes assessment articles and the results of various scientific research carried out by academics. We provide the authors with the opportunity to create and/or perfect their science writing skills. Thus, each issue of the journal (two per year and at least two supplements will contain professional articles from any academic field, authored by domestic and international academics. The goal of this journal is to pass on relevant information to undergraduate, graduate, and post-graduate students as well as to fellow academics and researchers; the topics covered are unlimited, considering its multi-disciplinary profile. Regarding the national and international visibility of Research and Science Today, it is indexed in over 30 international databases (IDB and is present in over 200 online libraries and catalogues; therefore, anybody can easily consult the articles featured in each issue by accessing the databases or simply the website.

  10. Research and Science Today Supplement No. 2/2015

    Directory of Open Access Journals (Sweden)

    Tudor Cosmin CIOCAN

    2015-04-01

    Full Text Available RESEARCH AND SCIENCE TODAY is a biannual science journal established in 2011. The journal is an informational platform that publishes assessment articles and the results of various scientific research carried out by academics. We provide the authors with the opportunity to create and/or perfect their science writing skills. Thus, each issue of the journal (two per year and at least two supplements will contain professional articles from any academic field, authored by domestic and international academics. The goal of this journal is to pass on relevant information to undergraduate, graduate, and post-graduate students as well as to fellow academics and researchers; the topics covered are unlimited, considering its multi-disciplinary profile. Regarding the national and international visibility of Research and Science Today, it is indexed in over 30 international databases (IDB and is present in over 200 online libraries and catalogues; therefore, anybody can easily consult the articles featured in each issue by accessing the databases or simply the website.

  11. Welding Curriculum.

    Science.gov (United States)

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

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

  12. Research on Ultrasonic Flaw Detection of Steel Weld in Spatial Grid Structure

    Science.gov (United States)

    Du, Tao; Sun, Jiandong; Fu, Shengguang; Zhang, Changquan; Gao, Qing

    2017-06-01

    The welding quality of spatial grid member is an important link in quality control of steel structure. The paper analyzed the reasons that the welding seam of small-bore pipe with thin wall grid structure is difficult to be detected by ultrasonic wave from the theoretical and practical aspects. A series of feasible detection methods was also proposed by improving probe and operation approaches in this paper, and the detection methods were verified by project cases. Over the years, the spatial grid structure is widely used the engineering by virtue of its several outstanding characteristics such as reasonable structure type, standard member, excellent space integrity and quick installation. The wide application of spatial grid structure brings higher requirements on nondestructive test of grid structure. The implementation of new Code for Construction Quality Acceptance of Steel Structure Work GB50205-2001 strengthens the site inspection of steel structure, especially the site inspection of ultrasonic flaw detection in steel weld. The detection for spatial grid member structured by small-bore and thin-walled pipes is difficult due to the irregular influence of sound pressure in near-field region of sound field, sound beam diffusion generated by small bore pipe and reduction of sensitivity. Therefore, it is quite significant to select correct detecting conditions. The spatial grid structure of welding ball and bolt ball is statically determinate structure with high-order axial force which is connected by member bars and joints. It is welded by shrouding or conehead of member bars and of member bar and bolt-node sphere. It is obvious that to ensure the quality of these welding positions is critical to the quality of overall grid structure. However, the complexity of weld structure and limitation of ultrasonic detection method cause many difficulties in detection. No satisfactory results will be obtained by the conventional detection technology, so some special

  13. Fine welding with lasers.

    Science.gov (United States)

    MacLellan, D

    2008-01-01

    The need for micro joining metallic alloys for surgical instruments, implants and advanced medical devices is driving a rapid increase in the implementation of laser welding technology in research, development and volume production. This article discusses the advantages of this welding method and the types of lasers used in the process.

  14. WOOD WELDING

    OpenAIRE

    Marcos Theodoro Muller; Rafael Rodolfo de Melo; Diego Martins Stangerlin

    2010-01-01

    The term "wood welding" designates what can be defined as "welding of wood surfaces". This new process, that it provides the joint of wood pieces without the use of adhesives or any other additional material, provokes growing interest in the academic environment, although it is still in laboratorial state. Linear friction welding induced bymechanical vibration yields welded joints of flat wood surfaces. The phenomenon of the welding occurs in less time than 10 seconds, with the temperature in...

  15. The UCAR SOARS Program: Strategies for Supplementing Undergraduate Research Experience

    Science.gov (United States)

    Pandya, R. E.

    2005-12-01

    Many REU programs have a goal of recruiting students to continue in the sciences. Undergraduate research is a successful strategy for engaging talented undergraduates to think about a career in science, encouraging them to purse graduate degrees, and for preparing them to succeed in graduate school. In the Significant Opportunities for Atmospheric Research (SOARS) program, we supplement undergraduate research with several strategies as part of an undergraduate-to-graduate bridge program aimed at broadening participation in the atmospheric and related sciences. In addition to a 10-week research program, SOARS also includes a formal mentoring program, writing workshop, vigorous learning community, and extensive professional development opportunities. Our presentation will describe these research-extending strategies in SOARS in more detail, with an eye toward how such strategies might be adapted for other programs. To do this, we will draw on the results of a major, independent evaluation of the SOARS program to determine the relative importance of these strategies in the overall success of the SOARS program. In the 10 yeas since SOARS creations, 98 students have participated in the program. Of those participants, 18 are still enrolled as undergraduates, and 55 have gone on to purse graduate school in the atmospheric sciences. Overall, this represents a graduate school placement rate of 69% and an overall retention rate of 82%. Of the 27 SOARS participants who have entered the workforce, 23 are in STEM related disciplines. Finally, 3 SOARS participants have already earned their PhD, and 32 have earned Master's. These numbers are especially significant given that SOARS participants come from groups that have been historically under-represented in the atmospheric sciences.

  16. Advanced Welding Concepts

    Science.gov (United States)

    Ding, Robert J.

    2010-01-01

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

  17. Experimental Research on Fatigue Failure for 2219-T6 Aluminum Alloy Friction Stir-Welded Joints

    Science.gov (United States)

    Sun, Guo-Qin; Niu, Jiang-Pei; Chen, Ya-Jing; Sun, Feng-Yang; Shang, De-Guang; Chen, Shu-Jun

    2017-08-01

    The fatigue experiment was executed for the 2219-T6 aluminum alloy friction stir-welded joints at the rotation speed of 800 r/min and the welding velocity of 150 mm/min. Most fatigue failures occurred in the weld nugget zone (WNZ), the thermo-mechanical affected zone and the nearby areas. The experimental results demonstrated that the sudden hardness gradient increases sites corresponding to the fatigue failure locations. The high-angle grain boundaries with the highest concentration were scattered within the WNZ. The microcracks initiated at the intersection of the soft grains. More than one crack initiation site was observed within the WNZ and the thermo-mechanical affected zone, when the fracture occurred in these areas. The rough surface of the welding area should be one of the main reasons for the fatigue failure occurrence. The fatigue crack growth rate in the WNZ at the first stage was fastest in comparison with the fatigue crack growth rate in the other areas of the joint.

  18. Resistance welding

    DEFF Research Database (Denmark)

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

    2003-01-01

    Resistance welding comprises not only the well known spot welding process but also more complex projection welding operations, where excessive plastic deformation of the weld point may occur. This enables the production of complex geometries and material combinations, which are often not possible...... to weld by traditional spot welding operations. Such joining processes are, however, not simple to develop due to the large number of parameters involved. Development has traditionally been carried out by large experimental investigations, but the development of a numerical programme system has changed...

  19. Research of Technological Properties of Steel X6CRNITI18-10 Welded Joints Exploited in Nitric Acid Medium

    Directory of Open Access Journals (Sweden)

    Gediminas Mikalauskas

    2016-04-01

    Full Text Available The repair of chemical industry equipments often requires to replace long time operated pipes or welded inserts with the simi-lar chemical composition. During the study the joints from corro-sion resistant steel X6CrNiTi18-10 were welded by manual metal arc welding with covered electrodes (MMA process 111 and tungsten inert gas welding (TIG process 141 at different welding parameters. The visual, radiographic, penetrant control and ferrite content analysis were carried out. The transverse tensile and bending samples were produced from welded samples; also the macroscopic and microscopic analyse were carried out.

  20. Research of state of metal welded joint by deformation and corrosion surface projection parameters

    Directory of Open Access Journals (Sweden)

    Demchenko Maria Vyacheslavovna

    2017-10-01

    Full Text Available At industrial enterprises in building structures and equipment one can see corrosion damage, as well as damage accumulated during operation period. The areas of stress concentration are welded joints as their structure is heterogeneous. From the point of view of the scale hierarchy, the welded joint represents the welded and base metal zones at the meso-macrolevel, the weld zone, the thermal zone, the base metal at the micro-mesolevel, the grain constituents at the nano-microlevel. Borders are the stress concentrators at different scale levels, thus they becomes the most dangerous places of metal structure. Modeling by the molecular dynamics method at the atomic level has shown nanocracks initiation in triple junctions of grain boundaries and on the ledges of the grain boundaries. Due to active development of nanotechnology, it became possible to evaluate the state of the weld metal at the nanoscale, where irreversible changes take place from the very beginning. Existing methods of nondestructive testing can detect damage only at the meso- and macrolevel. Modern equipment makes it possible to use other methods of control and approaches. For example, according to GOST R55046-2012 and R57223-2016, the analysis of the parameters of the surface projection deformation performed by confocal laser scanning microscopy should be taken into account when the evaluation of state of metal pipelines is carried out. However, there is a problem to monitore it due to various factors affecting the surface during operation. The paper proposes an additional method to estimate the state of weld metal at any stage of deformation that uses 3D analysis of the parameters of the «artificial» corrosion relief of surface. During the operation period changes in the stress-strain state and structure of the metal take place, as the result the character and depth of etching of the grains of the structural components and their boundaries change too. Evaluation of the

  1. Materials participation in welded joints manufacturing

    Science.gov (United States)

    Ghenghea, L. D.

    2016-08-01

    Management of materials dilution to form a joint with higher features asked by complex metallic structures is a problem that took attention and efforts of welding processes researchers and this communication will give a little contribution presenting some scientific and experimental results of dilution processes studied by Welding Research Group from Iasi, Romania, TCM Department. Liquid state welding processes have a strong dependence related to dilution of base and filler materials, the most important are for automatic joining using welding. The paper presents a review of some scientific works already published and their contributions, results of dilution coefficient evaluation using weighing, graphics and software applied for shielded metal arc welding process. Paper results could be used for welders’ qualification, welding procedure specification and other welding processes researchers’ activities. The results of Welding Research Group from Iasi, Romania, TCM Department, show dilution coefficient values between 20-30 % of base material and 70-80 % of filler material for studied welding process.

  2. Welding Technician

    Science.gov (United States)

    Smith, Ken

    2009-01-01

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

  3. 3D friction stir welding with a cost-efficient machine concept at Fraunhofer IWS: Presentation held at 6th Welding Research and Collaboration Colloquium - IIW, Hyderabad, 7th April 2016

    OpenAIRE

    Schulze, Sebastian; Grimm, Andreas; Standfuß, Jens; Beyer, Eckhard

    2016-01-01

    The increasing demand of cost efficiency and lightweight design can be considered as major drivers for the introduction of new materials and material combinations in the aircraft industry. Consequently new joining technologies and welding approaches are needed. Friction stir welding is one of these new joining technologies and can help to overcome typical welding problems, which are present when fusion welding or similar melting based welding technologies are enabled for hard to weld alloys o...

  4. TECHNOLOGICAL ISSUES IN MECHANISED FEED WIG/TIG WELDING SURFACING OF WELDING

    Directory of Open Access Journals (Sweden)

    BURCA Mircea

    2016-09-01

    manual welding tests in the light of using the process for welding surfacing being known that in such applications mechanised operations are recommended whenever possible given the latter strengths i.e. increased productivity and quality deposits. The research also aims at achieving a comparative a study between wire mechanised feed based WIG manual welding and the manual rod entry based manual welding in terms of geometry deposits, deposits aesthetics, operating technique, productivity, etc . In this regard deposits were made by means of two welding procedures, and subsequently welding surfacing was made with the optimum values of the welding parameters in this case.

  5. Experimental research on sealing of boreholes, shafts and ramps in welded tuff

    Energy Technology Data Exchange (ETDEWEB)

    Fuenkajorn, K. [Rock Engineering International, Tucson, AZ (United States)

    1996-04-01

    Laboratory and in-situ experiments have been conducted to determine the mechanical and hydraulic performance of cement borehole seals in densely welded Apache Leap tuff. Test results indicate that under saturated conditions, commercial expansive cement can provide good bond strength and adequate hydraulic performance for borehole seal under changing stress conditions. The cement seal should be installed at the intact portion of the opening, and should have a length-to-diameter ratio greater than four. Drying increases borehole plug permeability and decreases mechanical and hydraulic bonds at the plug-rock interface. In-situ testing indicates that installation procedure may significantly affect the cement plug performance.

  6. Survey of welding processes.

    Science.gov (United States)

    2003-07-01

    The current KYTC SPECIAL PROVISION NO. 4 WELDING STEEL BRIDGES prohibits the use of welding processes other than shielded metal arc welding (SMAW) and submerged arc welding (SAW). Nationally, bridge welding is codified under ANSI/AASHTO/AWS D1....

  7. Networking and Information Technology Research and Development. Supplement of the President's Budget for Fiscal Year 2006

    National Research Council Canada - National Science Library

    2005-01-01

    This Supplement to the President's Budget for Fiscal Year 2006 offers a brief technical outline of the 2006 budget request for the Networking and Information Technology Research and Development (NITRD) Program...

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

    Science.gov (United States)

    Hohhertz, Durwin

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

  9. Using Facebook to Supplement Participant Pools for Class Research Projects: Should We Like It?

    Science.gov (United States)

    Sciutto, Mark J.

    2015-01-01

    In-class research projects are a valuable way of providing research experience for undergraduate students in psychology. This article evaluates the use of online social networks to supplement sample recruitment for in-class research projects. Specifically, this article presents a systematic analysis of seven student research projects that…

  10. WELDING TORCH

    Science.gov (United States)

    Correy, T.B.

    1961-10-01

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

  11. Measuring weld heat to evaluate weld integrity

    Energy Technology Data Exchange (ETDEWEB)

    Schauder, V., E-mail: schauder@hks-prozesstechnik.de [HKS-Prozesstechnik GmbH, Halle (Germany)

    2015-11-15

    Eddy current and ultrasonic testing are suitable for tube and pipe mills and have been used for weld seam flaw detection for decades, but a new process, thermography, is an alternative. By measuring the heat signature of the weld seam as it cools, it provides information about weld integrity at and below the surface. The thermal processes used to join metals, such as plasma, induction, laser, and gas tungsten arc welding (GTAW), have improved since they were developed, and they get better with each passing year. However, no industrial process is perfect, so companies that conduct research in flaw detection likewise continue to develop and improve the technologies used to verify weld integrity: ultrasonic testing (UT), eddy current testing (ET), hydrostatic, X-ray, magnetic particle, and liquid penetrant are among the most common. Two of these are used for verifying the integrity of the continuous welds such as those used on pipe and tube mills: UT and ET. Each uses a transmitter to send waves of ultrasonic energy or electrical current through the material and a receiver (probe) to detect disturbances in the flow. The two processes often are combined to capitalize on the strengths of each. While ET is good at detecting flaws at or near the surface, UT penetrates the material, detecting subsurface flaws. One drawback is that sound waves and electrical current waves have a specific direction of travel, or an alignment. A linear defect that runs parallel to the direction of travel of the ultrasonic sound wave or a flaw that is parallel to the coil winding direction of the ET probe can go undetected. A second drawback is that they don't detect cold welds. An alternative process, thermography, works in a different fashion: It monitors the heat of the material as the weld cools. Although it measures the heat at the surface, the heat signature provides clues about cooling activity deep in the material, resulting in a thorough assessment of the weld's integrity It

  12. Plasma arc welding weld imaging

    Science.gov (United States)

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

    1994-01-01

    A welding torch for plasma arc welding apparatus has a transparent shield cup disposed about the constricting nozzle, the cup including a small outwardly extending polished lip. A guide tube extends externally of the torch and has a free end adjacent to the lip. First and second optical fiber bundle assemblies are supported within the guide tube. Light from a strobe light is transmitted along one of the assemblies to the free end and through the lip onto the weld site. A lens is positioned in the guide tube adjacent to the second assembly and focuses images of the weld site onto the end of the fiber bundle of the second assembly and these images are transmitted along the second assembly to a video camera so that the weld site may be viewed continuously for monitoring the welding process.

  13. WELDING METHOD

    Science.gov (United States)

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

    1959-09-29

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

  14. Influence of the Gap Width on the Geometry of the Welded Joint in Hybrid Laser-Arc Welding

    Science.gov (United States)

    Turichin, G.; Tsibulskiy, I.; Kuznetsov, M.; Akhmetov, A.; Mildebrath, M.; Hassel, T.

    The aim of this research was the experimental investigation of the influence of the gap width and speed of the welding wire on the changes of the geometry in the welded joint in the hybrid laser-arc welding of shipbuilding steel RS E36. The research was divided into three parts. First, in order to understand the influence of the gap width on the welded joint geometry, experimental research was done using continuous wave fiber laser IPG YLS-15000 with arc rectifier VDU-1500DC. The second part involved study of the geometry of the welded joint and hardness test results. Three macrosections from each welded joint were obtained. Influence of the gap width and welding wire speed on the welded joint geometry was researched in the three lines: in the right side of the plates, middle welded joint and in the root welded joint.

  15. EFFECTS OF ELECTRODE DEFORMATION OF RESISTANCE SPOT WELDING ON 304 AUSTENITIC STAINLESS STEEL WELD GEOMETRY

    Directory of Open Access Journals (Sweden)

    Nachimani Charde

    2012-12-01

    Full Text Available The resistance spot welding process is accomplished by forcing huge amounts of current flow from the upper electrode tip through the base metals to the lower electrode tip, or vice versa or in both directions. A weld joint is established between the metal sheets through fusion, resulting in a strong bond between the sheets without occupying additional space. The growth of the weld nugget (bond between sheets is therefore determined from the welding current density; sufficient time for current delivery; reasonable electrode pressing force; and the area provided for current delivery (electrode tip. The welding current and weld time control the root penetration, while the electrode pressing force and electrode tips successfully accomplish the connection during the welding process. Although the welding current and weld time cause the heat generation at the areas concerned (electrode tip area, the electrode tips’ diameter and electrode pressing forces also directly influence the welding process. In this research truncated-electrode deformation and mushrooming effects are observed, which result in the welded areas being inconsistent due to the expulsion. The copper to chromium ratio is varied from the tip to the end of the electrode whilst the welding process is repeated. The welding heat affects the electrode and the electrode itself influences the shape of the weld geometry.

  16. Tailoring defect free fusion welds based on phenomenological modeling

    Science.gov (United States)

    Kumar, Amit

    principles still remains an important milestone in changing welding from almost an empirical art to a mainstream science-based technology. The ability to determine multiple welding variable sets to achieve desired weld attributes, based on scientific principles, would be an important step to achieve this goal. Furthermore, no comprehensive unified theoretical model exists today that can predict the formation of commonly occurring humping defects considering the effects of important welding variables such as the arc current, voltage, welding speed, nature of the shielding gas, electrode geometry, torch angle and ambient pressure. In this research work, a model is developed to achieve desired weld attributes and avoid high speed weld defects like humping. (Abstract shortened by UMI.)

  17. Novel Process Revolutionizes Welding Industry

    Science.gov (United States)

    2008-01-01

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

  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. Cherry Creek Research Natural Area: guidebook supplement 41

    Science.gov (United States)

    Reid Schuller; Jennie Sperling; Tim. Rodenkirk

    2011-01-01

    This guidebook describes Cherry Creek Research Natural Area, a 239-ha (590-ac) area that supports old-growth Douglas-fir-western hemlock (Pseudotsuga menziesii- Tsuga heterophylla) forest occurring on sedimentary materials in the southern Oregon Coast Range. Major plant associations present within the area include the western hemlock/Oregon oxalis...

  20. Citability of Original Research and Reviews in Journals and Their Sponsored Supplements

    Science.gov (United States)

    Citrome, Leslie

    2010-01-01

    Background The contents of pharmaceutical industry sponsored supplements to medical journals are perceived to be less credible than the contents of their parent journals. It is unknown if their contents are cited as often. The objective of this study was to quantify the citability of original research and reviews contained in supplements and compare it with that for the parent journal. Methodology/Principal Findings This was a cohort study of 446 articles published in the Journal of Clinical Psychiatry (JCP) and its supplements for calendar years 2000 and 2005. The total citation counts for each article up to October 5, 2009 were retrieved from the ISI Web of Science database. The main outcome measure was the number of citations received by an article since publication. Regular journal articles included 114 from calendar year 2000 and 190 from 2005. Articles from supplements included 90 from 2000 and 52 from 2005. The median citation counts for the 3 years post-publication were 10 (interquartile range [IQR], 4–20), 14 (IQR, 8–20), 13.5 (IQR, 8–23), and 13.5 (IQR, 8–20), for the 2000 parent journal, 2000 supplements, 2005 parent journal, and 2005 supplements, respectively. Citation counts were higher for the articles in the supplements than the parent journal for the cohorts from 2000 (p = .02), and no different for the year 2005 cohorts (p = .88). The 2005 parent journal cohort had higher citation counts than the 2000 cohort (p = .007), in contrast to the supplements where citation counts remained the same (p = .94). Conclusions/Significance Articles published in JCP supplements are robustly cited and thus can be influential in guiding clinical and research practice, as well as shaping critical thinking. Because they are printed under the sponsorship of commercial interests, they may be perceived as less than objective. A reasonable step to help improve this perception would be to ensure that supplements are peer-reviewed in the same way as

  1. Citability of original research and reviews in journals and their sponsored supplements.

    Directory of Open Access Journals (Sweden)

    Leslie Citrome

    Full Text Available BACKGROUND: The contents of pharmaceutical industry sponsored supplements to medical journals are perceived to be less credible than the contents of their parent journals. It is unknown if their contents are cited as often. The objective of this study was to quantify the citability of original research and reviews contained in supplements and compare it with that for the parent journal. METHODOLOGY/PRINCIPAL FINDINGS: This was a cohort study of 446 articles published in the Journal of Clinical Psychiatry (JCP and its supplements for calendar years 2000 and 2005. The total citation counts for each article up to October 5, 2009 were retrieved from the ISI Web of Science database. The main outcome measure was the number of citations received by an article since publication. Regular journal articles included 114 from calendar year 2000 and 190 from 2005. Articles from supplements included 90 from 2000 and 52 from 2005. The median citation counts for the 3 years post-publication were 10 (interquartile range [IQR], 4-20, 14 (IQR, 8-20, 13.5 (IQR, 8-23, and 13.5 (IQR, 8-20, for the 2000 parent journal, 2000 supplements, 2005 parent journal, and 2005 supplements, respectively. Citation counts were higher for the articles in the supplements than the parent journal for the cohorts from 2000 (p = .02, and no different for the year 2005 cohorts (p = .88. The 2005 parent journal cohort had higher citation counts than the 2000 cohort (p = .007, in contrast to the supplements where citation counts remained the same (p = .94. CONCLUSIONS/SIGNIFICANCE: Articles published in JCP supplements are robustly cited and thus can be influential in guiding clinical and research practice, as well as shaping critical thinking. Because they are printed under the sponsorship of commercial interests, they may be perceived as less than objective. A reasonable step to help improve this perception would be to ensure that supplements are peer-reviewed in the same way as regular

  2. 75 FR 18034 - Defense Federal Acquisition Regulation Supplement; Research and Development Contract Type...

    Science.gov (United States)

    2010-04-08

    ... Regulation Supplement; Research and Development Contract Type Determination (DFARS Case 2006-D053) AGENCY... a major defense acquisition program (MDAP) to select the contract type for a development program... requires DoD to modify regulations regarding the determination of contract type for development programs...

  3. The impact of welding wire on the mechanical properties of welded joints

    Directory of Open Access Journals (Sweden)

    Magdalena Mazur

    2014-06-01

    Full Text Available This paper presents results of the mechanical properties of Hardox 450 steel welded joints. These welded joints were made in accordance with welding procedure specifications (WPS, which was prepared and  applied in the Wielton company. Fillers were provided by welding wires with two different diameters. The welding wire was G4Sil with diameter of 1.0 mm and 1.2 mm. The aim of this study was to examine whether the thickness of the welding wire has a direct effect on the properties of welded joints. Test specimens were made in similar parameters of the welding process. Then they were subjected to macroscopic research, tensile strength, impact strength and hardness

  4. Replacement Nuclear Research Reactor. Supplement to Draft Environmental Impact Statement. Volume 3

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1999-01-01

    The Draft Environmental Impact Statement for a replacement research reactor at Lucas Heights, was available for public examination and comment for some three months during 1998. A Supplement to the Draft Environmental Impact Statement (Draft EIS) has been completed and was lodged with Environment Australia on 18 January 1999. The Supplement is an important step in the overall environmental assessment process. It reviews submissions received and provides the proponent`s response to issues raised in the public review period. General issues extracted from submissions and addressed in the Supplement include concern over liability issues, Chernobyl type accidents, the ozone layer and health issues. Further studies, relating to issues raised in the public submission process, were undertaken for the Supplementary EIS. These studies confirm, in ANSTO`s view, the findings of the Draft EIS and hence the findings of the Final EIS are unchanged from the Draft EIS

  5. Laser welding of micro plastic parts

    Science.gov (United States)

    Haberstroh, E.; Hoffmann, W.-M.

    2007-02-01

    Most welding processes for plastics do not meet the demands of micro technology and thus cannot be applied in this innovative industrial sector. One of the few techniques which are applicable in this sector is the laser transmission welding, which has distinctive advantages like low mechanical and thermal load of the joining parts. This makes the laser particularly suitable for the welding of micro plastics parts. Thereby, contour welding is a process variant of laser transmission welding enabling the welding of complex and even three-dimensional weld contours. But so far it has not yet been applied for welding plastics parts of micro scale in the industrial practice. Recent research at the Institute of Plastics Processing (IKV) at the RWTH Aachen University shows the feasibility of this process to weld small and complex micro parts. Good mechanical properties can be achieved. However, it is necessary to apply measures to reduce the formation of flash. Moreover, it can be shown that there is a strong influence of some material parameters on the laser welding process so that some plastics are more suitable than others for the contour welding in micro technology.

  6. Application of TRIZ Methodology in Diffusion Welding System Optimization

    Science.gov (United States)

    Ravinder Reddy, N.; Satyanarayana, V. V.; Prashanthi, M.; Suguna, N.

    2017-12-01

    Welding is tremendously used in metal joining processes in the manufacturing process. In recent years, diffusion welding method has significantly increased the quality of a weld. Nevertheless, diffusion welding has some extent short research and application progress. Therefore, diffusion welding has a lack of relevant information, concerned with the joining of thick and thin materials with or without interlayers, on welding design such as fixture, parameters selection and integrated design. This article intends to combine innovative methods in the application of diffusion welding design. This will help to decrease trial and error or failure risks in the welding process being guided by the theory of inventive problem solving (TRIZ) design method. This article hopes to provide welding design personnel with innovative design ideas under research and for practical application.

  7. APPLICATION OF TRIZ METHODOLOGY IN DIFFUSION WELDING SYSTEM OPTIMIZATION

    Directory of Open Access Journals (Sweden)

    N. RAVINDER REDDY

    2017-10-01

    Full Text Available Welding is tremendously used in metal joining processes in the manufacturing process. In recent years, diffusion welding method has significantly increased the quality of a weld. Nevertheless, diffusion welding has some extent short research and application progress. Therefore, diffusion welding has a lack of relevant information, concerned with the joining of thick and thin materials with or without interlayers, on welding design such as fixture, parameters selection and inte-grated design. This article intends to combine innovative methods in the application of diffusion welding design. This will help to decrease trial and error or failure risks in the welding process being guided by the theory of inventive problem solving (TRIZ design method. This article hopes to provide welding design personnel with innovative design ideas under research and for practical application.

  8. Research and Development for Botanical Products in Medicinals and Food Supplements Market

    Directory of Open Access Journals (Sweden)

    Marco Miroddi

    2013-01-01

    Full Text Available Botanical products sold in the health area are generally intended as drugs, medicinal products, food supplements or substances for therapeutic use. Use of botanicals for improving or to care human health has evolved independently in different countries worldwide. Regulatory issues regarding botanical products designed for the food supplements or medicinal market and their influence on research and development are discussed. European Union (EU and United States (US policies regulating these products are focused with comments on the legislations delivered during the last ten years and differences existing in rules between these countries are emphasized. Research and development on botanical products nowdays strongly influenced by the product destination in the market. Addressed and differentiated research for either food supplements or medicinal markets is necessary to purchase data really useful for assessment of safe and effective use for both the categories. The main objective is to catalyze interest of academic and companies' researchers on crucial aspects to be taken into account in the research for the development of botanical products.

  9. Consumable Guide Electroslag Welding of 4 to 24 Inch Thick Carbon Steel Castings (The National Shipbuilding Research Program)

    Science.gov (United States)

    1986-08-01

    graphite inoculation, refractory shoes and combinations of these. Macrographs and micrographs are presented to show the effect on weld metal and HAZ...PER CENT CAD, 13-14 PER CENT AL203, 7-8 PER CENT MGO, 7-65 PER CENT CAF2, AND 7-25 PER CENT MN02. A REFRACTORY FIBRE IS USED TO SEAL THE COOLING SHOE...JOINTS, BUTT WELDS WITH VARIOUS JOINT SHAPES, INCLUDING LAMELLER TEARING AND LACK OF FUS1ON. THE EXAMINATION OF HOT METAL AND TEEMING LADLES , MADE OF

  10. The optimization of welding regime parameters at shielded metal arc welding (SMAW by mathematical modeling

    Directory of Open Access Journals (Sweden)

    V. Petrescu

    2016-04-01

    Full Text Available The realized researches followed the determining of mathematical models that allow the optimization of the welding process in order to obtain welded joints with certain values of the mechanical characteristics. Thus, there were established mathematical models of dependence of mechanical characteristics of welded joints (Rm, Rp02, Z, A, KCV 20°C of each parameter of welding regime (Iw, Uw, and also, mathematical models that offer cumulative dependence of mechanical characteristics of both parameters of welding regime.The researches have been carried out using steel E 36-4 as base material and as filler material basic electrodes, type E7018 and the applied welding procedure was the process: shielded metal arc welding (SMAW.

  11. New materials for welding and surfacing

    Science.gov (United States)

    Kozyrev, N. A.; Galevsky, G. V.; Kryukov, R. E.; Titova, D. A.; Shurupov, V. M.

    2016-09-01

    The paper provides description of research into the influence of new materials and technologies on quality parameters of welds and deposited metal carried out in the research and production centre “Welding processes and technologies”. New welding technologies of tanks for northern conditions are considered, as well as technologies of submerged arc welding involving fluxing agents AN - 348, AN - 60, AN - 67, OK.10.71 and carbon-fluorine containing additives; new flux cored wires and surfacing technologies, teaching programs and a trainer for welders are designed.

  12. Supplement A: Use Cases. A Companion to the OCLC Research Report, Registering Researchers in Authority Files

    Science.gov (United States)

    Smith-Yoshimura, Karen; Altman, Micah; Conlon, Michael; Cristán, Ana Lupe; Dawson, Laura; Dunham, Joanne; Hickey, Thom; Hill, Amanda; Hook, Daniel; Horstmann, Wolfram; MacEwan, Andrew; Schreur, Philip; Smart, Laura; Wacker, Melanie; Woutersen, Saskia

    2014-01-01

    This report is a companion piece to OCLC Research Report, "Registering Researchers in Authority Files" (ED564924). While the main report summarizes the results of the research conducted by the OCLC Research Registering Researchers in Authority Files Task Group in 2012-2014, details of this research are provided in these supplementary…

  13. Evaluation of Residual Stress Measurements Before and After Post-Weld Heat Treatment in the Weld Repairs

    Science.gov (United States)

    Pardowska, Anna M.; Price, John W. H.; Finlayson, Trevor R.; Ibrahim, R.

    2010-11-01

    Welding repairs are increasingly a structural integrity concern for aging pressure vessel and piping components. It has been demonstrated that the residual stress distribution near repair welds can be drastically different from that of the original weld. Residual stresses have a significant effect on the lifetime performance of a weld, and a reduction of these stresses is normally desirable. The aim of this paper is to investigate residual stresses in various weld repair arrangements using the non-destructive neutron diffraction technique. This research is focused on characterization of the residual stress distribution: (i) in the original weld; (ii) in a shallow toe weld repair; and (iii) after conventional post-weld heat treatment. The focus of the measurements is on the values of the subsurface strain/stress variations across the weld.

  14. Distortion Control during Welding

    OpenAIRE

    Akbari Pazooki, A.M.

    2014-01-01

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

  15. Welding process modelling and control

    Science.gov (United States)

    Romine, Peter L.; Adenwala, Jinen A.

    1993-01-01

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

  16. ITER lip seal welding and cutting developments

    Energy Technology Data Exchange (ETDEWEB)

    Levesy, B.; Cordier, J.J.; Jokinen, T. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Kujanpää, V.; Karhu, M. [VTT Technical Research Centre of Finland (Finland); Le Barbier, R. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France); Määttä, T. [VTT Technical Research Centre of Finland (Finland); Martins, J.P.; Utin, Y. [ITER Organization, Route de Vinon sur Verdon, 13115 Saint Paul Lez Durance (France)

    2015-10-15

    Highlights: • Different TIG and Laser welding techniques are tested. • Twin spot laser welding techniques is the best. • Limited heat input gives a stable weld pool in all positions. • Penetrations is achieved. • Lip seal welding and cutting with a robotic arm is successfully performed on a representative mock-up. - Abstract: The welded lip seals form part of the torus primary vacuum boundary in between the port plugs and the vacuum vessel, and are classified as Protection Important Component. In order to refurbish the port plugs or the in-vessel components, port plugs have to be removed from the machine. The lip seal design must enable up to ten opening of the vacuum vessel during the life time operation of the ITER machine. Therefore proven, remote reliable cutting and re-welding are essential, as these operations need to be performed in the port cells in a nuclear environment, where human presence will be restricted. Moreover, the combination of size of the components to be welded (∼10 m long vacuum compatible thin welds) and the congested environment close to the core of the machine constraint the type and size of tools to be used. This paper describes the lip seal cutting and welding development programme performed at the VTT Technical Research Centre, Finland. Potential cutting and welding techniques are analyzed and compared. The development of the cutting, TIG and laser welding techniques on samples are presented. Effects of lip seal misalignments and optimization of the 2 welding processes are discussed. Finally, the manufacturing and test of the two 1.2 m × 1 m representative mock-ups are presented. The set-up and use of a robotic arm for the mock-up cutting and welding operations are also described.

  17. The Effect Of Different Micro-Jet Streams Number On Plastic Properties Of Welds

    OpenAIRE

    Hadryś D.; Węgrzyn T.; Piwnik J.

    2015-01-01

    The main goal of that paper was analysing of plastic properties of welds made with micro-jet cooling. New technology of micro-jet welding could be regarded as a new way to improve plastic properties of welds. It allows to obtain welds with better properties in comparison to ordinary welding method. Moreover, it is possible to steering of weld structure and properties of the weld. During research Erichsen cupping tests and bending tests were carried out for welds made by MIG method with micro-...

  18. Welding and Joining of Titanium Aluminides

    Science.gov (United States)

    Cao, Jian; Qi, Junlei; Song, Xiaoguo; Feng, Jicai

    2014-01-01

    Welding and joining of titanium aluminides is the key to making them more attractive in industrial fields. The purpose of this review is to provide a comprehensive overview of recent progress in welding and joining of titanium aluminides, as well as to introduce current research and application. The possible methods available for titanium aluminides involve brazing, diffusion bonding, fusion welding, friction welding and reactive joining. Of the numerous methods, solid-state diffusion bonding and vacuum brazing have been most heavily investigated for producing reliable joints. The current state of understanding and development of every welding and joining method for titanium aluminides is addressed respectively. The focus is on the fundamental understanding of microstructure characteristics and processing–microstructure–property relationships in the welding and joining of titanium aluminides to themselves and to other materials. PMID:28788113

  19. Welding and Joining of Titanium Aluminides.

    Science.gov (United States)

    Cao, Jian; Qi, Junlei; Song, Xiaoguo; Feng, Jicai

    2014-06-25

    Welding and joining of titanium aluminides is the key to making them more attractive in industrial fields. The purpose of this review is to provide a comprehensive overview of recent progress in welding and joining of titanium aluminides, as well as to introduce current research and application. The possible methods available for titanium aluminides involve brazing, diffusion bonding, fusion welding, friction welding and reactive joining. Of the numerous methods, solid-state diffusion bonding and vacuum brazing have been most heavily investigated for producing reliable joints. The current state of understanding and development of every welding and joining method for titanium aluminides is addressed respectively. The focus is on the fundamental understanding of microstructure characteristics and processing-microstructure-property relationships in the welding and joining of titanium aluminides to themselves and to other materials.

  20. Welding and Joining of Titanium Aluminides

    Directory of Open Access Journals (Sweden)

    Jian Cao

    2014-06-01

    Full Text Available Welding and joining of titanium aluminides is the key to making them more attractive in industrial fields. The purpose of this review is to provide a comprehensive overview of recent progress in welding and joining of titanium aluminides, as well as to introduce current research and application. The possible methods available for titanium aluminides involve brazing, diffusion bonding, fusion welding, friction welding and reactive joining. Of the numerous methods, solid-state diffusion bonding and vacuum brazing have been most heavily investigated for producing reliable joints. The current state of understanding and development of every welding and joining method for titanium aluminides is addressed respectively. The focus is on the fundamental understanding of microstructure characteristics and processing–microstructure–property relationships in the welding and joining of titanium aluminides to themselves and to other materials.

  1. WELDING PROCESS

    Science.gov (United States)

    Zambrow, J.; Hausner, H.

    1957-09-24

    A method of joining metal parts for the preparation of relatively long, thin fuel element cores of uranium or alloys thereof for nuclear reactors is described. The process includes the steps of cleaning the surfaces to be jointed, placing the sunfaces together, and providing between and in contact with them, a layer of a compound in finely divided form that is decomposable to metal by heat. The fuel element members are then heated at the contact zone and maintained under pressure during the heating to decompose the compound to metal and sinter the members and reduced metal together producing a weld. The preferred class of decomposable compounds are the metal hydrides such as uranium hydride, which release hydrogen thus providing a reducing atmosphere in the vicinity of the welding operation.

  2. Repair welding of cast iron coated electrodes

    Science.gov (United States)

    Żuk, M.; Górka, J.; Dojka, R.; Czupryński, A.

    2017-08-01

    Welding cast iron is a complex production procedure. Repair welding was used to repair damaged or poorly made castings. This is due to a tendency to cracking of the material during welding as well as after it. Welding cast iron can be carried out on hot or on cold. Hot welding requires high heat material and the use of welding material in the form of cast iron. In the case of cold welding, it is possible to use different materials. Mostly used filler metals are nickel and copper based. The work shows the course of research concerning repairmen of ductile iron with arc welding method. For the reparation process four types of ESAB company coated electrodes dedicated for cast iron were used with diameter 3.2 and 4 mm: ES 18-8-6B (4mm), EB 150 (4mm), OK NiCl, EŻM. In the cast iron examined during the testing grooves were made using plasma methods, in order to simulate the removed casting flaws. Then the welding process with coated electrodes was executed. The process utilized low welding current row of 100A, so there would only be a small amount of heat delivered to the heat affected zone (HAZ). Short stitches were made, after welding it was hammered, in order to remove stresses. After the repair welding the part of studies commenced which purpose was finding surface defects using visual testing (VT) and penetration testing (PT). In the second part, a series of macro and microscopic studies were executed witch the purpose of disclosuring the structure. Then the hardness tests for welds cross sections were performed. An important aspect of welding cast iron is the colour of the padding weld after welding, more precisely the difference between the base material and padding weld, the use of different materials extra gives the extra ability to select the best variant. The research of four types of coated electrode was executed, based on the demands the best option in terms of aesthetic, strength and hardness.

  3. Laser-TIG Welding of Titanium Alloys

    Science.gov (United States)

    Turichin, G.; Tsibulsky, I.; Somonov, V.; Kuznetsov, M.; Akhmetov, A.

    2016-08-01

    The article presents the results of investigation the technological opportunity of laser-TIG welding of titanium alloys. The experimental stand for implementation of process with the capability to feed a filler wire was made. The research of the nature of transfer the filler wire into the welding pool has been demonstrated. The influence of distance between the electrode and the surface of the welded plates on the stability of the arc was shown. The relationship between welding velocity, the position of focal plane of the laser beam and the stability of penetration of plates was determined.

  4. 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...

  5. Analysis of the Mechanism of Longitudinal Bending Deformation Due to Welding in a Steel Plate by Using a Numerical Model

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Rae; Yan, Jieshen; Kim, Jae-Woong [Yeungnam Univ., Gyeongsan (Korea, Republic of); Song, Gyu Yeong [Gyeongbuk Hybrid Technology Institute, Yeongcheon (Korea, Republic of)

    2017-01-15

    Welding deformation is a permanent deformation that is caused in structures by welding heat. Welding distortion is the primary cause of reduced productivity, due to welded structural strength degradation, low dimensional accuracy, and appearance. As a result, research and numerous experiments are being carried out to control welding deformation. The aim of this study is to analyze the mechanism of longitudinal bending deformation due to welding. Welding experiments and numerical analyses were performed for this study. The welding experiments were performed on 4 mm and 8.5 mm thickness steel plates, and the numerical analysis was conducted on the welding deformation using the FE software MSC.marc.

  6. Friction Stir Welding

    Science.gov (United States)

    Nunes, Arthur C., Jr.

    2008-01-01

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

  7. Effect of Submerged Arc Welding Parameters on the Microstructure of SA516 and A709 Steel Welds

    Science.gov (United States)

    Amanie, James

    The effects of submerged arc welding (SAW) current and speed on the microstructures of SA516 grade 70 and A709 grade 50 steel welds were studied in this research. Steel plates 17 mm-thick were submerged arc welded using different welding currents (from 700 to 850 A) and welding speeds (from 5.3 to 15.3 mm/s). The effect of heat input on the weld metal chemistry, morphologies and chemistry of inclusions and nucleation of acicular ferrite (AF), grain boundary ferrite (GBF) and Widmanstatten ferrite (WF) were evaluated. Optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS) microanalysis and transmission electron microscopy (TEM) were used to examine the microstructures of the developed weld joints. PAX-it image analysis software program was utilized for quantitative analysis of the microstructures. The results showed that it is difficult to ascribe changes in the microstructure that occurred in the heat affected zone (HAZ) and the weld metal regions to a single welding process parameter. Inclusion analysis revealed two types of inclusions formed in the weld metals for both steels. They are spherical and faceted inclusions. It was also observed that acicular ferrite nucleated only on the spherical inclusions. EDS analysis showed that the two inclusions have different chemical compositions. The results further showed that the total oxygen content of the weld metals of both steels generally increased with welding current, but decreased with increasing welding speed. The prior austenite grain width decreased with increasing welding speed, but increased with increasing welding current (increased heat input). For both SA516 and A709 steel welds, the proportion of acicular ferrite (AF) in the weld metals increased initially, while those of grain boundary ferrite (GBF) and Widmanstatten ferrite (WF) decreased with increasing welding current when welding current was increased from 700 A to 800 A. With further increase in the

  8. Original Research: The Effects of Red Yeast Rice Supplementation on Cholesterol Levels in Adults.

    Science.gov (United States)

    Peng, Diane; Fong, Amy; Pelt, Amanda van

    2017-08-01

    : Purpose: Red yeast rice (RYR) supplementation has become a popular alternative to statin therapy in treating hypercholesterolemia. This state-of-the-science review seeks to explore the most recent evidence on the effectiveness and safety of RYR supplementation in treating dyslipidemic adults. This review extends the time frame of a meta-analysis performed by Li and colleagues in 2014; specifically, we looked at the literature published between September 2013 and April 2016. We conducted a search of four electronic databases-PsycINFO, CINAHL, PubMed, and Scopus-using the terms red yeast rice and cholesterol. We excluded studies that included berberine or lovastatin. Fifteen articles met the inclusion criteria. Eleven articles reported on randomized controlled trials, one reported on an open-label pilot study, and one reported on an open-label clinical trial. Two articles were meta-analyses. The 13 studies involved a total of 1,246 participants, with an additional 7,467 participants reported in the two meta-analyses. Significant reductions in low-density lipoprotein cholesterol and total cholesterol levels with RYR supplementation were observed in all trials. There were no significant changes in liver and kidney function, and 10 studies noted no significant changes in creatine kinase levels. Although RYR appears to be a safe and effective lipid-lowering agent, there is insufficient evidence to support the recommendation of RYR supplementation to patients. Further research is needed, including long-term studies, studies that include participants with comorbidities and complex medical histories, and studies that take into account the variability of formulation and dosage of RYR in the marketplace.

  9. Integration and development in schizotypy research: an introduction to the special supplement.

    Science.gov (United States)

    Debbané, Martin; Mohr, Christine

    2015-03-01

    In its fifth decade of existence, the construct of schizotypy is recapturing the early scientific interest it attracted when Paul E. Meehl (1920-2003), who coined the term, pioneered the field of schizotypy research. The International Lemanic Workshop on Schizotypy, hosted at the University of Geneva in December 2013, recently offered an opportunity to address some of the fundamental questions in contemporary schizotypy research and situate the construct in the greater scheme of future scientific projects on schizophrenia and psychological health research. What kind of knowledge has schizotypy research provided in furthering our understanding of schizophrenia? What types of questions can schizotypy research tackle, and which are the conceptual and methodological frameworks to address them? How will schizotypy research contribute to future scientific endeavors? The International Lemanic Workshop brought together leading experts in the field around the tasks of articulating the essential findings in schizotypy research, as well as providing some key insights and guidance to face scientific challenges of the future. The current supplement contains 8 position articles, 4 research articles, and 1 invited commentary that outline the state of the art in schizotypy research today. © The Author 2015. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  10. Introduction to Welding.

    Science.gov (United States)

    Fortney, Clarence; Gregory, Mike

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

  11. Distortion Control during Welding

    NARCIS (Netherlands)

    Akbari Pazooki, A.M.

    2014-01-01

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

  12. Welding of a metal-polymer laminate

    NARCIS (Netherlands)

    Gower, H.L.

    2007-01-01

    The purpose of this work is to investigate the weldability of a metal polymer sandwich structure. The welding of the sandwich material proceeds first by welding of the skin layer. The material selected for this research is Steelite, a sandwich structure developed by Corus, with 0.12 mm thick mild

  13. 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.

  14. A COMPARATIVE STUDY OF GROOVE DESIGN AND WELDING PROCESS ON SHRINKAGE STRESS, RESIDUAL STRESS AND TENSILE PROPERTIES OF P91 STEEL

    OpenAIRE

    Vinay Kumar Pal*, Dr. L. P. Singh, C.Pandey

    2017-01-01

    Present research work deals with the selection of appropriate range of welding parameters and procedure that is used for conventional and narrow groove welding of thick sections at different welding process.The development of narrow gap welding procedure by P-GMAW process is carried out for joining of thick sections by appropriate reduction in number of weld passes and amount of weld metal. Study of the effect of variation in groove design and welding processes was performed by summarizing th...

  15. Effect of post weld impact treatment (PWIT) on mechanical properties of spot-welded joint

    Science.gov (United States)

    Ghazali, F. A.; Salleh, Z.; Hyie, K. M.; Rozlin, N. M. Nik; Hamidi, S. H. Ahmad; Padzi, M. M.

    2017-12-01

    This paper focuses on the study of improvement for spot welding on the tensile shear and hardness by applying post weld impact treatment (PWIT) on the welded joint. The main objective of the research is to characterize and improve the mechanical properties of the joint. The method of PWIT used on the welded joint was Pneumatic Impact Treatment (PIT). The concept of PIT on spot welding is that it improves the mechanical properties of the welded zone. The working sample was undergoing a resistance spot welding of joining two similar in dimension and material of a steel plate before treated. The dimension of both plate are 110 mm × 45 mm × 1.2 mm and the material used were low carbon steel (LCS). All the welded samples were tested for its mechanical properties by performing the tensile-shear and hardness test. Tensile-shear test was conducted on the spot welded, both treated and as-welded samples using crosshead speed of 2 mm/min, while hardness test was performed using 1kgf load via Vickers hardness indenter. The effects of PIT on tensile-shear properties and hardness were evaluated and found that the implementation of PIT has increased tensile shear and hardness significantly.

  16. Does the evidence make a difference in consumer behavior? Sales of supplements before and after publication of negative research results.

    Science.gov (United States)

    Tilburt, Jon C; Emanuel, Ezekiel J; Miller, Franklin G

    2008-09-01

    To determine if the public consumption of herbs, vitamins, and supplements changes in light of emerging negative evidence. We describe trends in annual US sales of five major supplements in temporal relationship with publication of research from three top US general medical journals published from 2001 through early 2006 and the number of news citations associated with each publication using the Lexus-Nexis database. In four of five supplements (St. John's wort, echinacea, saw palmetto, and glucosamine), there was little or no change in sales trends after publication of research results. In one instance, however, dramatic changes in sales occurred following publication of data suggesting harm from high doses of vitamin E. Results reporting harm may have a greater impact on supplement consumption than those demonstrating lack of efficacy. In order for clinical trial evidence to influence public behavior, there needs to be a better understanding of the factors that influence the translation of evidence in the public.

  17. Manganese in occupational arc welding fumes--aspects on physiochemical properties, with focus on solubility.

    Science.gov (United States)

    Taube, Fabian

    2013-01-01

    Physicochemical properties, such as particle sizes, composition, and solubility of welding fumes are decisive for the bioaccessibility of manganese and thereby for the manganese cytotoxic and neurotoxic effects arising from various welding fumes. Because of the diverse results within the research on welding fume solubility, this article aims to review and discuss recent literature on physicochemical properties of gas metal arc welding, shielded metal arc welding, and flux-cored arc welding fumes, with focus on solubility properties. This article also presents a short introduction to the literature on arc welding techniques, health effects from manganese, and occupational exposure to manganese among welders.

  18. Structural and mechanical properties of welded joints of reduced activation martensitic steels

    Energy Technology Data Exchange (ETDEWEB)

    Filacchioni, G. E-mail: gianni.filacchioni@casaccia.enea.it; Montanari, R.; Tata, M.E.; Pilloni, L

    2002-12-01

    Gas tungsten arc welding and electron beam welding methods were used to realise welding pools on plates of reduced activation martensitic steels. Structural and mechanical features of these simulated joints have been investigated in as-welded and post-welding heat-treated conditions. The research allowed to assess how each welding technique affects the original mechanical properties of materials and to find suitable post-welding heat treatments. This paper reports results from experimental activities on BATMAN II and F82H mod. steels carried out in the frame of the European Blanket Project - Structural Materials Program.

  19. Modal testing and finite element model updating of laser spot welds

    Science.gov (United States)

    Abu Husain, N.; Haddad Khodaparast, H.; Snaylam, A.; James, S.; Sharp, M.; Dearden, G.; Ouyang, H.

    2009-08-01

    Spot welds are used extensively in automotive engineering. One of the latest manufacturing techniques for producing spot welds is Laser Welding. Finite element (FE) modelling of laser welds for dynamic analysis is a research issue because of the complexity and uncertainty of the welds and thus formed structures. In this work, FE model of the welds is developed by employing CWELD element in NASTRAN and its feasibility for representing laser spot welds is investigated. The FE model is updated based on the measured modal data of hat-plate structures and cast as a structural minimisation problem by the application of NASTRAN codes.

  20. 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...... and the weld pool, has also prevented the realization of a closed-loop control system for many years, even though a variety of sensors have been developed. Among all the sensor systems, visual sensors have the advantage of receiving visual information and have been drawn more and more attentions. Typical...... 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...

  1. Fine particles in welding workshop; Hitsaamon pienhiukkaset

    Energy Technology Data Exchange (ETDEWEB)

    Haenninen, H.; Koskinen, A. [Helsinki Unviv. of Technology, Materials Sciences and Engineering, Espoo (Finland)

    2006-10-15

    The objectives of the project were to research ultra- fine particles developed in the welding and cutting processes, to classify the particles in the welding fume, as well as to assess how they transform in air and drift in the internal air. Also it was attempted to decrease the amount of ultra-fine particles in the welding processes and in the internal air. Experiments were performed in the laboratory environments so that the results are valid and comparable. The fine particles in the fumes were measured and sampled by cascade impactors (ELPI, DLPI), by SMPS and by filter samplers (personal and area). The composition, size, shape and activity of the particles were determined. During the project efficiency of personal welding helmets, fume extraction welding guns and MFI-precipitator were tested. Tests were carried out in the laboratory and in the industrial workshops. The three-year project started in the beginning of February 2003. (orig.)

  2. Reprocessing weld and method

    Energy Technology Data Exchange (ETDEWEB)

    Killian, M.L.; Lewis, H.E.

    1993-08-03

    A process is described for improving the fatigue resistance of a small primary structural weld at a joint between structural members of a weldment, the weld having been made with the welding energy input of E[sub 1], the process comprising: applying a reprocessing weld on at least a portion of either one or both toes of the primary structural weld, thereby covering said toe portion, the reprocessing weld containing a filler metal and having a cross-sectional area which is less than the corresponding cross-sectional area of the primary structural weld, the reprocessing weld extending onto the face of the primary structural weld at one side of the toe portion covered and onto the structural member at the other side of the toe portion covered, and the total welding energy input, E[sub 2], used in said reprocessing the primary structural weld being less than the welding energy input E[sub 1] of the primary structural weld.

  3. Weld-brazing of titanium

    Science.gov (United States)

    Bales, T. T.; Royster, D. M.; Arnold, W. E., Jr.

    1974-01-01

    A joining process, designated weld-brazing, which combines resistance spotwelding and brazing has been developed at the NASA Langley Research Center. Resistance spot-welding is employed to position and align the parts and to establish a suitable faying surface gap for brazing; it contributes to the integrity of the joint. Brazing enhances the properties of the joint and reduces the stress concentrations normally associated with spotwelds. Ti-6Al-4V titanium alloy joints have been fabricated using 3003 aluminum braze both in a vacuum furnace and in a retort containing an inert gas environment.

  4. Analysis of the Covered Electrode Welding Process Stability on the Basis of Linear Regression Equation

    Directory of Open Access Journals (Sweden)

    Słania J.

    2014-10-01

    Full Text Available The article presents the process of production of coated electrodes and their welding properties. The factors concerning the welding properties and the currently applied method of assessing are given. The methodology of the testing based on the measuring and recording of instantaneous values of welding current and welding arc voltage is discussed. Algorithm for creation of reference data base of the expert system is shown, aiding the assessment of covered electrodes welding properties. The stability of voltage–current characteristics was discussed. Statistical factors of instantaneous values of welding current and welding arc voltage waveforms used for determining of welding process stability are presented. The results of coated electrodes welding properties are compared. The article presents the results of linear regression as well as the impact of the independent variables on the welding process performance. Finally the conclusions drawn from the research are given.

  5. Friction Stir Spot Welding of 6061 Aluminum-to-Copper

    Science.gov (United States)

    Heideman, Robert J.

    Friction stir spot welding (FSSW) between 1.5mm thick 6061 Al on top and 1.5mm thick Cu at bottom was conducted. First, weld parameters and the weld macrostructure that were necessary to form good quality welds, as determined using lap shear weld strength, were identified. Tool rotation speed and tool pin length are key variables that control weld strength. To obtain high quality strong welds, a Cu ring extruded upward from the lower Cu sheet into the upper 6061 Al-sheet, which promoted bonding and interlocking between the sheets, and an Al-rich stir zone between Cu ring and weld keyhole were both necessary. Second, a technique where the tool remained in the sample after FSSW helped determine the material flow that takes place during high quality weld formation and the functions of the welding tool features. The tool threads cause 6061 Al from the upper sheet to move downward into the region near the threads. The tool shoulder causes a counter flow movement of 6061 Al that results in the formation of the Al-rich stir zone and also causes the upward extrusion of the lower Cu sheet. This technique also identified that a Cu-rich material forms on the tool tip, that this material sheds and rebuilds during subsequent welds, and that this material can form large Cu-rich particles that can completely fill the tool threads, impede proper material flow and lead to a low strength, poor quality weld. Third, to further understand welding parameters, weld temperatures, torque, and vertical forces were measured. Temperature data was collected using a tool holder that permitted wireless thermocouple data collection. Through these measurements, rotational plunge weld energy was recognized as important in determining if a quality weld formed, and weld plunge rate was identified as the welding parameter that significantly impacted rotational weld plunge energy. The final phase of research was to improve weld quality consistency. Through repetitive trials with a single tool

  6. Research highlights from the UIC/NIH Center for Botanical Dietary Supplements Research for Women’s Health: Black cohosh from the field to the clinic

    Science.gov (United States)

    Farnsworth, Norman R; Mahady, Gail B.

    2009-01-01

    In 1999, the Department of Medicinal Chemistry and Pharmacognosy at the College of Pharmacy, University of Illinois (UIC) at Chicago was funded to establish a Botanical Dietary Supplements Research Center from the National Institutes of Health (NIH). The emphasis of the UIC/NIH Center for Botanical Dietary Supplements Research (CBDSR) is botanical dietary supplements (BDS) for women's health. Center’s research has focused on BDS that may improve women's health and quality of life, specifically in the areas of menopause, premenstrual syndrome, and persistent urinary tract infections. Center investigators have overcome many challenges associated with botanical dietary supplements research, including acquiring and identifying plant species for investigation, isolating and identifying active constituents, elucidating the mechanisms of action of these botanicals, and conducting phase I and phase II clinical studies. Black cohosh [Actaea racemosa L. (Ranunculaceae)] has been used as a model to illustrate the steps involved in taking a botanical dietary supplement from the field, all the way to clinical trials. Bioassays are described that were necessary to elucidate the pertinent biological studies of plant extracts and their mechanisms of action. The Center has used an innovative multidisciplinary approach to this type of research, and thus has been very successful in fulfilling its specific aims. PMID:20161501

  7. Handbook of Plastic Welding

    DEFF Research Database (Denmark)

    Islam, Aminul

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

  8. Report Summarizing the Effort Required to Initiate Welding of Irradiated Materials within the Welding Cubicle

    Energy Technology Data Exchange (ETDEWEB)

    Frederick, Greg [Electric Power Research Institute (EPRI), Palo Alto, CA (United States); Sutton, Benjamin J. [Electric Power Research Institute (EPRI), Palo Alto, CA (United States); Tatman, Jonathan K. [Electric Power Research Institute (EPRI), Palo Alto, CA (United States); Vance, Mark Christopher [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Smith, Allen W. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Clark, Scarlett R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feng, Zhili [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Miller, Roger G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chen, Jian [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tang, Wei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Hu, Xunxiang [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gibson, Brian T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-06-01

    The advanced welding facility within a hot cell at the Radiochemical Engineering Development Center of Oak Ridge National Laboratory (ORNL), which has been jointly funded by the U.S. Department of Energy (DOE), Office of Nuclear Energy, Light Water Reactor Sustainability Program and the Electric Power Research Institute, Long Term Operations Program and the Welding and Repair Technology Center, is in the final phase of development. Research and development activities in this facility will involve direct testing of advanced welding technologies on irradiated materials in order to address the primary technical challenge of helium induced cracking that can arise when conventional fusion welding techniques are utilized on neutron irradiated stainless steels and nickel-base alloys. This report details the effort that has been required since the beginning of fiscal year 2017 to initiate welding research and development activities on irradiated materials within the hot cell cubicle, which houses welding sub-systems that include laser beam welding (LBW) and friction stir welding (FSW) and provides material containment within the hot cell.

  9. Welding Course Curriculum.

    Science.gov (United States)

    Genits, Joseph C.

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

  10. Instructional Guidelines. Welding.

    Science.gov (United States)

    Fordyce, H. L.; Doshier, Dale

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

  11. Effects of nitrogen and strain age embrittlement on toughness of MMA welds. A final report on the joint reserach project - GKSS Research Centre, Geesthacht, Germany, and Oerlikon Welding Ltd., Zurich, Switzerland

    Energy Technology Data Exchange (ETDEWEB)

    Kocak, M. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Materialforschung; Achar, D.R.G.; Evans, G.M. [OERLIKON Welding Ltd., Zurich (Switzerland)

    1998-12-31

    A detailed literature review has been carried out on the topic to identify the areas requiring further investigations. Based on this investigations have been carried out to evaluate the influence of dissolved nitrogen in weld metals on their toughness and strain aging behaviour through fracture mechanics as well as conventional impact testing approaches. MMA C-Mn steel weld metals bearing nitrogen between 80 to 210 ppm were investigated under four different post-weld conditions, namely: 1. as welded, 2. stress relieved, 3. artificially strain aged and 4. artificially strain aged and stress relieved. Quantitative metallography and low load microhardness studies of microphases were integral part of these investigations. The results demonstrate the highly detrimental effect of nitrogen on the toughness behaviour of C-Mn steel weld metal particularly under strain aging conditions. This is substantiated through decrease of acicular ferrite with the accompanying increase in primary ferrite and ferrite with second phases in the microstructures. Also, there is a distinctive increase in acicular ferrite microhardness. Post-weld stress relieving heat treatment under these conditions effects only marginal improvement in toughness and shifts the fracture behaviour from brittle to ductile or quasi-ductile only in the case of low nitrogen weld metals. Comparing the results of the CTOD and Charpy tests, it is observed that both methods measure the influence of nitrogen on toughness behaviour in the same trend but the magnitudes of the effect measured are different whereby the fracture mechanics method appears very conservative. (orig.) [Deutsch] Untersucht werden der Einfluss von Stickstoff im Bereich von 80-120 ppm auf die Zaehigkeit und Reckalterungsversproedungs-Verhaeltnisse des C-Mn-Strahlschweissgutes. Die Pruefungen erfolgen mit technologischen Kerbschlagbiege- und CTOD-Versuchen an Schweissguetern, die durch mehrlagiges Lichtbogenschweissen hergestellt wurden, unter vier

  12. New welding information system on the internet (Prediction of the properties of weld heat-affected zones

    Directory of Open Access Journals (Sweden)

    M Fujita

    2003-08-01

    Full Text Available To promote continuous transfer and development of welding technology, a new system for predicting the microstructures and mechanical properties of welded joins has been built on the Internet. It combines a database system containing continuous cooling transformation diagrams (CCT diagrams for welding and an expert system for computing weld thermal histories. In addition, this system employs a technique which was invented during the development of another distributed database system called "Data-Free-Way" , which was designed to contain information advanced nuclear materials and materials obtained from other programs of welding research at NIMS in the past. This paper describes the current state of our new system for computing weld thermal histories to predict the properties of welded joints using the CCT diagrams database, which is now available on the Internet. Some problems encountered with the database used in such a system are also referred to.

  13. Design and Optimal Research of a Non-Contact Adjustable Magnetic Adhesion Mechanism for a Wall-Climbing Welding Robot

    Directory of Open Access Journals (Sweden)

    Minghui Wu

    2013-01-01

    Full Text Available Wall-climbing welding robots (WCWRs can replace workers in manufacturing and maintaining large unstructured equipment, such as ships. The adhesion mechanism is the key component of WCWRs. As it is directly related to the robot's ability in relation to adsorbing, moving flexibly and obstacle-passing. In this paper, a novel non-contact adjustably magnetic adhesion mechanism is proposed. The magnet suckers are mounted under the robot's axils and the sucker and wall are in non-contact. In order to pass obstacles, the sucker and the wheel unit can be pulled up and pushed down by a lifting mechanism. The magnetic adhesion force can be adjusted by changing the height of the gap between the sucker and the wall by the lifting mechanism. In order to increase the adhesion force, the value of the sucker's magnetic energy density (MED is maximized by optimizing the magnet sucker's structure parameters with a finite element method. Experiments prove that the magnetic adhesion mechanism has enough adhesion force and that the WCWR can complete wall-climbing work within a large unstructured environment.

  14. An overview of the welding technologies of CLAM steels for fusion application

    Energy Technology Data Exchange (ETDEWEB)

    Chen Xizhang, E-mail: kernel.chen@gmail.com [School of Materials Science and Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China); Huang Yuming [School of Materials Science and Engineering, Jiangsu University, ZhenJiang, Jiangsu 212013 (China); Madigan, Bruce [Montana Tech. of University of Montana, Butte, MT 59701 (United States); Zhou Jianzhong [School of Mechanical Engineering, Jiangsu University, ZhenJiang, Jiangsu 221013 (China)

    2012-09-15

    Highlights: Black-Right-Pointing-Pointer Welding technologies of China Low Activation Martensitic steel is overviewed. Black-Right-Pointing-Pointer Most welding technologies in use are discussed and suggestions are given. Black-Right-Pointing-Pointer Proper welding technologies could ensure weld properties but more detailed work are necessary. - Abstract: China Low Activation Martensitic steel (CLAMs), a kind of RAFM steel with Chinese intellectual property rights, is considered as the primary structural material for the China-designed ITER test blanket module (TBM). As one of the key issues in the fabrication of the fusion reactor, the welding technologies of CLAMs are reviewed. Emphasis is placed on the weldability of CLAMs by different welding methods, and on the properties of as-welded and post-weld heat-treated joints. Recent highlights in research and development for the welding of CLAMs show that proper welding procedure could provide welds with adequate tensile strength but the welds exhibit lower impact toughness compared with the base metal. Post-weld heat treatment (PWHT) and the application of ultrasonic energy during TIG welding could dramatically improve impact toughness. Research also shows that welds in CLAMs have sufficient resistance to swelling under irradiation as well as suitable compatibility with liquid LiPb. The microstructure, mechanical and other physical properties of welds are significantly different from those of the base metal due to the complicated welding thermal cycle. The weld joint is the area most likely to fail one or more of the design requirements within the fusion reactor. Therefore significant additional research is necessary to ensure safe application of welded CLAM steel for fusion reactor construction.

  15. Main alloy elements in covered electrodes in terms of the amount of oxygen in weld metal deposits (WMD

    Directory of Open Access Journals (Sweden)

    T. Węgrzyn

    2012-04-01

    Full Text Available There were investigated properties of WMD, especially metallographic structure, toughness and fatigue strength of welds with various oxygen amount. The connection between the properties of welds with the content of oxygen in WMD were carried out. The research results indicate that it should be limited oxygen content in steel welds. Subsequent researchers could find more precisely the most beneficial oxygen amount in the welds in terms of the amount of acicular ferrite in welds.

  16. Supplemental Educational Services: An Action Science Research Study of Achieving State Standards for Provider Effectiveness

    Science.gov (United States)

    McClintock, Cynthia Collette

    2012-01-01

    Supplemental educational services are designed to contribute tremendous support to local school districts and communities through state-approved provider programs. The state, however, prior to approving supplemental educational services provider programs, must utilize all available resources to assist in the process of screening and approving…

  17. Iron supplements: scientific issues concerning efficacy and implications for research and programs.

    Science.gov (United States)

    Allen, Lindsay H

    2002-04-01

    Iron supplementation remains an important strategy for the prevention and treatment of iron deficiency anemia and can produce substantial improvements in the functional performance of iron deficient individuals and populations. Many potential benefits of iron supplementation require further exploration, including its effect on vitamin A and iodine metabolism. There is strong evidence that vitamin A and riboflavin deficiencies affect iron utilization from supplements and are important on a global scale, but little evidence that folate and vitamin B-12 deficiencies play a major causal role in the global burden of anemia. The efficacy of multiple micronutrient supplements for the prevention and treatment of anemia must be further evaluated. Because weekly supplementation with iron is effective at improving iron status, this option should be thoroughly explored and evaluated in the context of programs for the prevention and the treatment of iron deficiency and anemia. More conformation is warranted concerning the number of tablets that must be consumed in different situations, and the efficacy of supplying other micronutrients weekly with iron. Weekly supplementation programs may improve the logistical and economic constraints that currently limit the provision of supplements to the many target population groups for whom they are recommended, but usually fail to reach. Further work is required to clarify the purpose, delivery and outcomes of iron supplementation programs.

  18. 75 FR 62838 - Award of a Single-Source Expansion Supplement to the Research Foundation of CUNY on Behalf of...

    Science.gov (United States)

    2010-10-13

    ... HUMAN SERVICES Administration for Children and Families Award of a Single-Source Expansion Supplement to the Research Foundation of CUNY on Behalf of Hunter College School of Social Work AGENCY: Children's.... ] Project Period: September 30, 2010 to September 29, 2011. SUMMARY: The Administration for Children and...

  19. Ultrasonic assessment of tension shear strength in resistance spot welding

    Science.gov (United States)

    Moghanizadeh, Abbas

    2015-05-01

    Resistance spot welding is extensively used to join sheet steel in the automotive industry. Ultrasonic non-destructive techniques for evaluation of the mechanical properties of resistance spot welding are presented. The aim of this study is to develop the capability of the ultrasonic techniques as an efficient tool in the assessment of the welding characterization. Previous researches have indicated that the measurements of ultrasonic attenuation are sensitive to grain- size variations in an extensive range of metallic alloys. Other researchers have frequently described grain sizes which are able to have significant effects on the physical characteristics of the material. This research provides a novel method to estimate the tension-shear strengths of the resistance spot welding directly from the ultrasonic attenuation measurements. The effects of spot welding parameters on the ultrasonic waves are further investigated. The results confirm that it is possible to determine the spot welding parameters for individual quality by using ultrasonic test.

  20. Physics of arc welding

    Science.gov (United States)

    Eagar, T. W.

    1982-05-01

    A discussion of the factors controlling the size and shape of the weld fusion zone is presented along with a description of current theories of heat and fluid flow phenomena in the plasma and the molten metal weld pool. Although experimental results confirm that surface tension, plasma jets, and weld pool convection all strongly influence the fusion zone shape; no comprehensive model is available from which to predict welding behavior. It is proposed that the lack of such an understanding is a major impediment to development of automated welding processes. In addition, sensors for weld torch positioning are reviewed in terms of the mechnical and electromagnetic energy spectra which have been used. New developments in this area are also needed in order to advance the technology of automated welding.

  1. Dual wire weld feed proportioner

    Science.gov (United States)

    Nugent, R. E.

    1968-01-01

    Dual feed mechanism enables proportioning of two different weld feed wires during automated TIG welding to produce a weld alloy deposit of the desired composition. The wires are fed into the weld simultaneously. The relative feed rates of the wires and the wire diameters determine the weld deposit composition.

  2. Bringing Pulsed Laser Welding into Production

    DEFF Research Database (Denmark)

    Olsen, Flemmming Ove

    1996-01-01

    In this paper, some research and develop-ment activities within pulsed laser welding technology at the Tech-nical University of Denmark will be described. The laser group at the Insti-tute for Manufacturing Technology has nearly 20 years of experience in laser materials process-ing. Inter......-nationally the group is mostly known for its contri-butions to the development of the laser cutting process, but further it has been active within laser welding, both in assisting industry in bringing laser welding into production in several cases and in performing fundamental R & D. In this paper some research...... activities concerning the weldability of high alloyed austenitic stainless steels for mass production industry applying industrial lasers for fine welding will be described. Studies on hot cracking sensitivity of high alloyed austenitic stainless steel applying both ND-YAG-lasers and CO2-lasers has been...

  3. Microstructures and electrochemical behaviors of the friction stir welding dissimilar weld.

    Science.gov (United States)

    Shen, Changbin; Zhang, Jiayan; Ge, Jiping

    2011-06-01

    By using optical microscope, the microstructures of 5083/6082 friction stir welding (FSW) weld and parent materials were analyzed. Meanwhile, at ambient temperature and in 0.2 mol/L NaHS03 and 0.6 mol/L NaCl solutionby gravimetric test, potentiodynamic polarization curve test, electrochemical impedance spectra (EIS) and scanning electron microscope (SEM) observation, the electrochemical behavior of 5083/6082 friction stir welding weld and parent materials were comparatively investigated by gravimetric test, potentiodynamic polarization curve test, electrochemical impedance spectra (EIS) and scanning electron microscope (SEM) observation. The results indicated that at given processing parameters, the anti-corrosion property of the dissimilar weld was superior to those of the 5083 and 6082 parent materials. Copyright © 2011 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

  4. Creep of service-aged welds

    OpenAIRE

    Sun, Wei

    1996-01-01

    The creep behaviour of welds in service-aged pipes are studied. The aims of the research have been achieved using analytical, numerical and experimental approaches to the relevant subjects. Several features of the work are presented: (i) a systematic parametric study of the creep of two-material test specimens including a stress singularity analysis, (ii) an impression creep testing method using a rectangular indenter, which can be applied to study the creep properties in welds, and (iii) met...

  5. Experimental Studies of Welding Effects on Damping for Undersea Warfare Applications

    National Research Council Canada - National Science Library

    Carey, Agustin

    2002-01-01

    .... The purpose of this research is to study the effects that welding has on damping. Measurements and comparisons of the damping ratios of two welded stiffened plates, two flat plates and one machined stiffened plate are undertaken...

  6. Laser welding of polymers, compatibility and mechanical properties

    DEFF Research Database (Denmark)

    Nielsen, Steen Erik; Strange, Marianne; Kristensen, Jens Klæstrup

    2013-01-01

    Laser welding of polymers is today a commonly used industrial technology. It has shown obvious advantages compared to e.g. adhesive bonding in terms of higher productivity, better quality and easiness for automation. The ongoing development of lasers tailored for polymer welding in coordination...... for research and development. This paper presents some research results related to laser welding of various polymer materials, including weld compatibility investigations related to the joining of different polymers. Theory for bonding mechanisms, strength development, mechanical properties testing and other...

  7. Measurement of Laser Weld Temperatures for 3D Model Input

    Energy Technology Data Exchange (ETDEWEB)

    Dagel, Daryl [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Grossetete, Grant [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Maccallum, Danny O. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-10-01

    Laser welding is a key joining process used extensively in the manufacture and assembly of critical components for several weapons systems. Sandia National Laboratories advances the understanding of the laser welding process through coupled experimentation and modeling. This report summarizes the experimental portion of the research program, which focused on measuring temperatures and thermal history of laser welds on steel plates. To increase confidence in measurement accuracy, researchers utilized multiple complementary techniques to acquire temperatures during laser welding. This data serves as input to and validation of 3D laser welding models aimed at predicting microstructure and the formation of defects and their impact on weld-joint reliability, a crucial step in rapid prototyping of weapons components.

  8. Automated generation of weld path trajectories.

    Energy Technology Data Exchange (ETDEWEB)

    Sizemore, John M. (Northrop Grumman Ship Systems); Hinman-Sweeney, Elaine Marie; Ames, Arlo Leroy

    2003-06-01

    AUTOmated GENeration of Control Programs for Robotic Welding of Ship Structure (AUTOGEN) is software that automates the planning and compiling of control programs for robotic welding of ship structure. The software works by evaluating computer representations of the ship design and the manufacturing plan. Based on this evaluation, AUTOGEN internally identifies and appropriately characterizes each weld. Then it constructs the robot motions necessary to accomplish the welds and determines for each the correct assignment of process control values. AUTOGEN generates these robot control programs completely without manual intervention or edits except to correct wrong or missing input data. Most ship structure assemblies are unique or at best manufactured only a few times. Accordingly, the high cost inherent in all previous methods of preparing complex control programs has made robot welding of ship structures economically unattractive to the U.S. shipbuilding industry. AUTOGEN eliminates the cost of creating robot control programs. With programming costs eliminated, capitalization of robots to weld ship structures becomes economically viable. Robot welding of ship structures will result in reduced ship costs, uniform product quality, and enhanced worker safety. Sandia National Laboratories and Northrop Grumman Ship Systems worked with the National Shipbuilding Research Program to develop a means of automated path and process generation for robotic welding. This effort resulted in the AUTOGEN program, which has successfully demonstrated automated path generation and robot control. Although the current implementation of AUTOGEN is optimized for welding applications, the path and process planning capability has applicability to a number of industrial applications, including painting, riveting, and adhesive delivery.

  9. 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.

  10. A CMOS Visual Sensing System for Welding Control and Information Acquirement in SMAW Process

    Science.gov (United States)

    Anren, Yao; Zhen, Luo; Sansan, Ao

    A sequential research work on visual information of manual arc welding pool dynamics are presented in this paper. An optical inspection system, for monitoring the shielded manual arc welding (SMAW) process is described. The system consisted of a vision sensor that consisted of a Complementary Metal Oxide Semiconductor (CMOS) camera and lenses, image processing algorithms, and a computer controller. During welding, an image of the weld pool and its vicinity was captured when basic current of welding power. Experimental results showed that the temperature signal varies greatly in the case of instabilities of the weld pool that cause weld defects. The visual information acquirement methods are focused in computer vision sensing, image processing and characteristic extraction of the weld pool surface from the single-item pool images by particular algorithms control strategies are developed to control welding pool dynamics during SMAW.

  11. Fabrication of niobium superconducting accelerator cavity by electron beam welded joints

    Science.gov (United States)

    Saha, T. K.; Mondal, J.; Mittal, K. C.; Bhushan, K. G.; Bapat, A. V.

    2012-11-01

    Fabrication of superconducting cavities has been taken up as a part of the development of accelerator driven sub critical system (ADSS) by Bhabha Atomic Research Centre. Large grain (RRR>99) pure niobium was chosen as the material for the cavity. Niobium,for its application as superconductor requires extremely high quality joints, feasible only by electron beam welding at high vacuum environment. An indigenously developed 100kV, 4kW high vacuum electron beam welding machine has been utilized to carry out the welding operations. Planning of the weld sequences was chalked out. Holding fixtures for the cavity, consists of seven numbers of joints have been fabricated beforehand. A few coupons were welded for optimization of the weld parameters and for inspection of the weld purity by indigenously developed secondary ion mass spectroscopy. The report describes the welding equipment and the stage wise joining operations of the cavity in details and also discusses the qualification testing of the welded cavity.

  12. Welding skate with computerized controls

    Science.gov (United States)

    Wall, W. A., Jr.

    1968-01-01

    New welding skate concept for automatic TIG welding of contoured or double-contoured parts combines lightweight welding apparatus with electrical circuitry which computes the desired torch angle and positions a torch and cold-wire guide angle manipulator.

  13. Computerized adaptive control weld skate with CCTV weld guidance project

    Science.gov (United States)

    Wall, W. A.

    1976-01-01

    This report summarizes progress of the automatic computerized weld skate development portion of the Computerized Weld Skate with Closed Circuit Television (CCTV) Arc Guidance Project. The main goal of the project is to develop an automatic welding skate demonstration model equipped with CCTV weld guidance. The three main goals of the overall project are to: (1) develop a demonstration model computerized weld skate system, (2) develop a demonstration model automatic CCTV guidance system, and (3) integrate the two systems into a demonstration model of computerized weld skate with CCTV weld guidance for welding contoured parts.

  14. Monitoring and Control of the Hybrid Laser-Gas Metal-Arc Welding Process

    Energy Technology Data Exchange (ETDEWEB)

    Kunerth, D. C.; McJunkin, T. R.; Nichol, C. I.; Clark, D.; Todorov, E.; Couch, R. D.; Yu, F.

    2013-07-01

    Methods are currently being developed towards a more robust system real time feedback in the high throughput process combining laser welding with gas metal arc welding. A combination of ultrasonic, eddy current, electronic monitoring, and visual techniques are being applied to the welding process. Initial simulation and bench top evaluation of proposed real time techniques on weld samples are presented along with the concepts to apply the techniques concurrently to the weld process. Consideration for the eventual code acceptance of the methods and system are also being researched as a component of this project. The goal is to detect defects or precursors to defects and correct when possible during the weld process.

  15. Aluminum Lithium Alloy 2195 Fusion Welding Improvements with New Filler Wire

    Science.gov (United States)

    Russell, C.

    2001-01-01

    The objective of this research was to assess the B218 weld filler wire for Super Lightweight External Tank production, which could improve current production welding and repair productivity. We took the following approaches: (1) Perform a repair weld quick look evaluation between 4043/B218 and B218/B218 weld filler wire combinations and evaluation tensile properties for planished and unplanished conditions; and (2) Perform repair weld evaluation on structural simulation panel using 4043-B218 and B218/B218 weld filler wire combinations and evaluation tensile and simulated service fracture properties for planished and unplanished conditions.

  16. The Study of Complex (Ti, Zr, Cs) Nanopowder Influencing the Effective Ionization Potential of Arc Discharge When Mma Welding

    Science.gov (United States)

    Sapozhkov, S. B.; Burakova, E. M.

    2016-08-01

    Strength is one of the most important characteristics of a weld joint. Mechanical properties of a weld metal can be improved in a variety of ways. One of the possibilities is to add a nanopowder to the weld metal. Authors of the paper suggest changing the production process of MMA welding electrodes via adding nanopowder Ti, Zr, Cs to electrode components through liquid glass. Theoretical research into the nanopowder influence on the effective ionization potential (Ueff) of welding arc discharge is also necessitated. These measures support arcing stability, improve strength of a weld joint, as the consequence, ensure quality enhancing of a weld joint and the structure on the whole.

  17. Ultrasonic Stir Welding

    Science.gov (United States)

    Nabors, Sammy

    2015-01-01

    NASA Marshall Space Flight Center (MSFC) developed Ultrasonic Stir Welding (USW) to join large pieces of very high-strength metals such as titanium and Inconel. USW, a solid-state weld process, improves current thermal stir welding processes by adding high-power ultrasonic (HPU) energy at 20 kHz frequency. The addition of ultrasonic energy significantly reduces axial, frictional, and shear forces; increases travel rates; and reduces wear on the stir rod, which results in extended stir rod life. The USW process decouples the heating, stirring, and forging elements found in the friction stir welding process allowing for independent control of each process element and, ultimately, greater process control and repeatability. Because of the independent control of USW process elements, closed-loop temperature control can be integrated into the system so that a constant weld nugget temperature can be maintained during welding.

  18. Simulation of Temperature Distribution in TIG Spot Welds of(Al-Mg) Alloy Using Finite Element Method

    OpenAIRE

    Ahlam Abid Ameer Alkhafajy; Abdul Hussain G. Al-Maliky; Muna K Abbas

    2008-01-01

    This research concern to analyse and simulate the temperature distribution in the spot welding joints using tungsten arc welding shielded with inert gas (TIG Spot) for the aluminum-magnesium alloy type (5052-O). The effect of and the quantity of the heat input that enter the weld zone has been investigated welding current, welding time and arc length on temperature distribution. The finite element method (by utilizing programme ANSYS 5.4) is presented the temperature distribution in a circula...

  19. Dual wire welding torch and method

    Science.gov (United States)

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

    2009-04-28

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2009-07-01

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

  1. Complete Report on the Development of Welding Parameters for Irradiated Materials

    Energy Technology Data Exchange (ETDEWEB)

    Frederick, Greg [Electric Power Research Inst. (EPRI), Knoxville, TN (United States); Sutton, Benjamin J. [Electric Power Research Inst. (EPRI), Knoxville, TN (United States); Tatman, Jonathan K. [Electric Power Research Inst. (EPRI), Knoxville, TN (United States); Vance, Mark Christopher [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Clark, Scarlett R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feng, Zhili [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Miller, Roger G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Chen, Jian [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Tang, Wei [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Gibson, Brian T. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-11-01

    The advanced welding facility at the Radiochemical Engineering Development Center of Oak Ridge National Laboratory, which was conceived to enable research and development of weld repair techniques for nuclear power plant life extension, is now operational. The development of the facility and its advanced welding capabilities, along with the model materials for initial welding trials, were funded jointly by the U.S. Department of Energy, Office of Nuclear Energy, Light Water Reactor Sustainability Program, the Electric Power Research Institute, Long Term Operations Program and the Welding and Repair Technology Center, with additional support from Oak Ridge National Laboratory. Welding of irradiated materials was initiated on November 17, 2017, which marked a significant step in the development of the facility and the beginning of extensive welding research and development campaigns on irradiated materials that will eventually produce validated techniques and guidelines for weld repair activities carried out to extend the operational lifetimes of nuclear power plants beyond 60 years. This report summarizes the final steps that were required to complete weld process development, initial irradiated materials welding activities, near-term plans for irradiated materials welding, and plans for post-weld analyses that will be carried out to assess the ability of the advanced welding processes to make repairs on irradiated materials.

  2. Studies of welded joints

    Directory of Open Access Journals (Sweden)

    J. M. Krupa

    2010-07-01

    Full Text Available Studies of a welded joint were described. The joint was made as a result of the reconstruction of a truss and one of the possible means to make a repair. The studies were of a simulation character and were targeted at the detection of welding defects and imperfections thatshould be eliminated in a real structure. A model was designed and on this model the tests and examinations were carried out. The modelwas made under the same conditions as the conditions adopted for repair. It corresponded to the real object in shape and dimensions, and in the proposed technique of welding and welding parameters. The model was composed of five plates joined together with twelve beads.The destructive and non-destructive tests were carried out; the whole structure and the respective welds were also examined visually. Thedefects and imperfections in welds were detected by surface methods of inspection, penetration tests and magnetic particle flaw detection.The model of the welded joint was prepared by destructive methods, a technique that would never be permitted in the case of a realstructure. For the investigations it was necessary to cut out the specimens from the welded joint in direction transverse to the weld run. The specimens were subjected to metallographic examinations and hardness measurements. Additionally, the joint cross-section was examined by destructive testing methods to enable precise determination of the internal defects and imperfections. The surface methods were applied again, this time to determine the severity of welding defects. The analysis has proved that, fabricated under proper conditions and with parameters of the welding process duly observed, the welded joint has good properties and repairs of this type are possible in practice.

  3. Hybrid laser arc welding: State-of-art review

    Science.gov (United States)

    Acherjee, Bappa

    2018-02-01

    Hybrid laser arc welding simultaneously utilizes the arc welding and the laser welding, in a common interaction zone. The synergic effects of laser beam and eclectic arc in the same weld pool results in an increase of welding speed and penetration depth along with the enhancement of gap bridging capability and process stability. This paper presents the current status of this hybrid technique in terms of research, developments and applications. Effort is made to present a comprehensive technical know-how about this process through a systematic review of research articles, industrial catalogues, technical notes, etc. In the introductory part of the review, an overview of the hybrid laser arc welding is presented, including operation principle, process requirements, historical developments, benefits and drawbacks of the process. This is followed by a detailed discussion on control parameters those govern the performance of hybrid laser arc welding process. Thereafter, a report of improvements of performance and weld qualities achieved by using hybrid welding process is presented based on review of several research papers. The succeeding sections furnish the examples of industrial applications and the concluding remarks.

  4. 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.

  5. Robot welding process control

    Science.gov (United States)

    Romine, Peter L.

    1991-01-01

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

  6. Explosive Welding of Pipes

    Science.gov (United States)

    Drennov, Oleg; Drennov, Andrey; Burtseva, Olga

    2013-06-01

    For connection by welding it is suggested to use the explosive welding method. This method is rather new. Nevertheless, it has become commonly used among the technological developments. This method can be advantageous (saving material and physical resources) comparing to its statical analogs (electron-beam welding, argon-arc welding, plasma welding, gas welding, etc.), in particular, in hard-to-reach areas due to their geographic and climatic conditions. Explosive welding of cylindrical surfaces is performed by launching of welded layer along longitudinal axis of construction. During this procedure, it is required to provide reliable resistance against radial convergent strains. The traditional method is application of fillers of pipe cavity, which are dense cylindrical objects having special designs. However, when connecting pipes consecutively in pipelines by explosive welding, removal of the fillers becomes difficult and sometimes impossible. The suggestion is to use water as filler. The principle of non-compressibility of liquid under quasi-dynamic loading is used. In one-dimensional gasdynamic and elastic-plastic calculations we determined non-deformed mass of water (perturbations, which are moving in the axial direction with sound velocity, should not reach the layer end boundaries for 5-7 circulations of shock waves in the radial direction). Linear dimension of the water layer from the zone of pipe coupling along axis in each direction is >= 2R, where R is the internal radius of pipe.

  7. Practical significance of weld strength matching

    Energy Technology Data Exchange (ETDEWEB)

    Sloterdijk, W. [N.V. Nederlandse Gasunie, Groningen (Netherlands); Schipaanboord, W.N. [N.V. Nederlandse Gasunie, Groningen (Netherlands)

    1996-10-01

    Defect tolerance in welds in pipelines constructed in modern high strength material depends on the balance in strength between weld material and pipe material. The Guidelines on the assessment of girth weld defects published by the European Pipeline Research Group (EPRG) define in Tier 2 defect limits assuming that the (actual) weld metal yield strength is equal or greater than the yield strength of the parent material. The defect limits according to Tier 2 exceed the defect limits in `workmanship standards` (l>25 mm). Nevertheless, the draft European welding standard EN 288 does not yet require a test to measure and verify the weld metal yield strength. Gasunie has performed a test program with the aim to look at the practical significance of weld strength matching in a strain controlled situation and to verify the relevance of limits given in the European welding and line pipe codes, in combination with the EPRG Guidelines. It is concluded that the results of the tests confirm the defect acceptance limits according to Tier 2 of the EPRG Guidelines. (orig.) [Deutsch] Die Zulaessigkeit von Fehlern in Rundschweissnaehten in Rohrleitungen aus modernen hochfesten Baustaehlen haengt von dem Verhaeltnis der Werkstofffestigkeit des Schweissgutes zu der des Grundwerkstoffs ab. Die von der European Pipeline Research Group (EPRG) veroeffentlichte Richtlinie zur Bewertung von Schweissnahtfehlern gibt in der zweiten Bewertungsstufe (Tier 2) Werte fuer zulaessige Schweissnahtfehlergroessen unter der Bedingung an, dass die Dehngrenze des Schweissgutes groesser oder gleich der Dehngrenze des Grundwerkstoffs ist. Die nach Tier 2 zulaessigen Fehler sind groesser als die in `Good-workmanship`-Regelwerken angegebenen Fehlerlaenge (l>25 mm). Demgegenueber fehlt im Entwurf der europaeischen Schweissnorm EN 288 bislang ein solcher Dehngrenzennachweis. Gasunie hat ein Versuchsprogramm durchgefuehrt, um die Bedeutung der Schweissgutfestigkeit bei dehnungskontrollierter Belastung sowie

  8. Friction stir welding of Aluminium matrix composites – A Review

    Directory of Open Access Journals (Sweden)

    Subramanya Prabhu

    2018-01-01

    Full Text Available Friction stir welding (FSW is established as one of the prominent welding techniques to join aluminium matrix composites (AMCs. It is a solid state welding process, takes place well below the melting temperature of the material, eliminates the detrimental effects of conventional fusion welding process. Although the process is capable to join AMCs, challenges are still open that need to be fulfill to widen its applications. This paper gives the outline of the friction stir welding technique used to join AMCs. Effect of process variables on the microstructure and mechanical properties of the joints, behavior of reinforcing materials during welding, effect of tool profiles on the joint strength are discussed in detail. Few improvements and direction for future research are also proposed.

  9. Pulse current gas metal arc welding characteristics, control and applications

    CERN Document Server

    Ghosh, Prakriti Kumar

    2017-01-01

    This monograph is a first-of-its-kind compilation on high deposition pulse current GMAW process. The nine chapters of this monograph may serve as a comprehensive knowledge tool to use advanced welding engineering in prospective applications. The contents of this book will prove useful to the shop floor welding engineer in handling this otherwise critical welding process with confidence. It will also serve to inspire researchers to think critically on more versatile applications of the unique nature of pulse current in GMAW process to develop cutting edge welding technology.

  10. Weld-brazing of titanium. [resistance spot welding combined with brazing

    Science.gov (United States)

    Bales, T. T.; Royster, D. M.; Arnold, W. E., Jr.

    1973-01-01

    A joining process, designated weld-brazing, which combines resistance spot-welding and brazing has been developed at the NASA Langley Research Center. Resistance spot-welding is employed to position and aline the parts and to establish a suitable faying surface gap for brazing and contributes to the integrity of the joint. Brazing enhances the properties of the joint and reduces the stress concentrations normally associated with spotwelds. Ti-6Al-4V titanium alloy joints have been fabricated using 3003 aluminum braze both in a vaccum furnace and in a retort containing an inert gas environment.

  11. Intelligent Control of Modular Robotic Welding Cell

    Energy Technology Data Exchange (ETDEWEB)

    Smartt, Herschel Bernard; Kenney, Kevin Louis; Tolle, Charles Robert

    2002-04-01

    Although robotic machines are routinely used for welding, such machines do not normally incorporate intelligent capabilities. We are studying the general problem of formulating usable levels of intelligence into welding machines. From our perspective, an intelligent machine should: incorporate knowledge of the welding process, know if the process is operating correctly, know if the weld it is making is good or bad, have the ability to learn from its experience to perform welds, and be able to optimize its own performance. To this end, we are researching machine architecture, methods of knowledge representation, decision making and conflict resolution algorithms, methods of learning and optimization, human/machine interfaces, and various sensors. This paper presents work on the machine architecture and the human/machine interface specifically for a robotic, gas metal arc welding cell. Although the machine control problem is normally approached from the perspective of having a central body of control in the machine, we present a design using distributed agents. A prime goal of this work is to develop an architecture for an intelligent machine that will support a modular, plug and play standard. A secondary goal of this work is to formulate a human/machine interface that treats the human as an active agent in the modular structure.

  12. An integrated approach for predictive control of extrusion weld seams: experimental support

    NARCIS (Netherlands)

    Bakker, A.J. den; Werkhoven, R.J.; Sillekens, W.H.; Katgerman, L.

    2010-01-01

    In hollow aluminium extrusions, longitudinal weld-seams are formed through a solid-state bonding process at elevated temperatures and under conditions of interfacial pressure and plastic deformation. For structurally loaded components, sound weld seams are imperative. In our research, a weld seam

  13. Modeling of plasma and thermo-fluid transport in hybrid welding

    Science.gov (United States)

    Ribic, Brandon D.

    processes parameters on heat transfer, fluid flow, and plasma characteristics for arc and laser welding. However, numerical modeling of laser/GTA hybrid welding is just beginning. Arc and laser welding plasmas have been previously analyzed successfully using optical emission spectroscopy in order to better understand arc and laser plasma properties as a function of plasma radius. Variation of hybrid welding plasma properties with radial distance is not known. Since plasma properties can affect arc and laser energy absorption and weld integrity, a better understanding of the change in hybrid welding plasma properties as a function of plasma radius is important and necessary. Material composition influences welding plasma properties, arc and laser energy absorption, heat transfer, and fluid flow. The presence of surface active elements such as oxygen and sulfur can affect weld pool fluid flow and bead geometry depending upon the significance of heat transfer by convection. Easily vaporized and ionized alloying elements can influence arc plasma characteristics and arc energy absorption. The effects of surface active elements on heat transfer and fluid flow are well understood in the case of arc and conduction mode laser welding. However, the influence of surface active elements on heat transfer and fluid flow during keyhole mode laser welding and laser/arc hybrid welding are not well known. Modeling has been used to successfully analyze the influence of surface active elements during arc and conduction mode laser welding in the past and offers promise in the case of laser/arc hybrid welding. A critical review of the literature revealed several important areas for further research and unanswered questions. (1) The understanding of heat transfer and fluid flow during hybrid welding is still beginning and further research is necessary. (2) Why hybrid welding weld bead width is greater than that of laser or arc welding is not well understood. (3) The influence of arc power and

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

    Science.gov (United States)

    2015-11-01

    to the 24–25 ksi YS of friction stir welds of 5059, which are not proportionally efficient to 5059 YS. High levels of YS are important to maintain...Technology Organisation, Materials Research Laboratories; 1983 June. Report No.: MRL-R-888. 8. Hori H. Tensile properties of friction stir welded ...joints – studies on characteristics of friction stir welded joints in structural aluminum alloys (Report 3). Welding International. 2007;21(9):626

  15. Laser Welding in Space

    Science.gov (United States)

    Workman, Gary L.; Kaukler, William F.

    1989-01-01

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

  16. DC arc weld starter

    Science.gov (United States)

    Campiotti, Richard H.; Hopwood, James E.

    1990-01-01

    A system for starting an arc for welding uses three DC power supplies, a high voltage supply for initiating the arc, an intermediate voltage supply for sustaining the arc, and a low voltage welding supply directly connected across the gap after the high voltage supply is disconnected.

  17. A Probabilistic Damage Tolerance Concept for Welded Joints

    DEFF Research Database (Denmark)

    Lassen, T.; Sørensen, John Dalsgaard

    2002-01-01

    The first part of this paper presented the required statistics and stochastic models for reliability analysis of the fatigue fracture of welded plate joints. This present Part 2 suggests a probabilistic damage tolerance supplement to the design S–N curves for welded joints. The goal is to provide...... are presented as dimensionless matrices and suggested for use in support of decision-making at the design stage, without any advanced fracture mechanics modelling and stochastic simulation. One important advantage of this format is that the probability levels are presented regardless of actual weld class...... and target service life (TSL). This is obtained by introducing the FDF as a key parameter to the results. This parameter is defined as the ratio of predicted fatigue life over TSL. FDF is always calculated in the S–N approach which is mandatory in fatigue life prediction. Various welded details (classes...

  18. Press releases issued by supplements industry organisations and non-industry organisations in response to publication of clinical research findings: a case-control study.

    Science.gov (United States)

    Wang, Michael T M; Gamble, Greg; Bolland, Mark J; Grey, Andrew

    2014-01-01

    Dietary supplement use is increasing despite lack of evidence of benefits, or evidence of harm. Press releases issued by the supplements industry might contribute to this situation by using 'spin' (strategies to hype or denigrate findings) to distort the results of clinical studies. We assessed press releases issued in response to publication of clinical studies on dietary supplements. We analyzed 47 supplements industry press releases and 91 non-industry press releases and news stories, generated in response to 46 clinical studies of dietary supplements published between 1/1/2005 and 5/31/2013. The primary outcome was 'spin' content and direction. We also assessed disposition towards use of dietary supplements, reporting of study information, and dissemination of industry press releases. More supplements industry press releases (100%) contained 'spin' than non-industry media documents (55%, Pindustry than non-industry media documents for studies reporting benefit of supplements (median 'spin' score 3.3, 95% CI 1.0-5.5 vs 0.5, 0-1.0; Pindustry than non-industry media documents for studies reporting no effect (6.0, 5.0-7.0 vs 0, 0-0; PIndustry press releases advocated supplement use in response to >90% of studies that reported no benefit, or harm, of the supplement. Industry press releases less frequently reported study outcomes, sample size, and estimates of effect size than non-industry media documents (all PIndustry press releases were referenced by 148 news stories on the websites of 6 organizations that inform manufacturers, retailers and consumers of supplements. Dietary supplements industry press releases issued in response to clinical research findings are characterized by 'spin' that hypes results that are favourable to supplement use and denigrates results that are not.

  19. 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

  20. Optimization of process parameters during vibratory welding technique using Taguchi's analysis

    Directory of Open Access Journals (Sweden)

    Pravin Kumar Singh

    2016-09-01

    Full Text Available With an aim to improve the mechanical properties of a weld joint, a new concept of vibratory setup has been designed which is capable to stir the molten weld pool before it solidifies during shielded metal arc welding (SMAW operation. Mechanical vibration having resonance frequency of 300 Hz and amplitude of 0.5 mm was transferred to the molten weld pool of 6 mm thick mild steel butt-welded joints during the welding operation. The experimental work was conducted at various ranges of frequencies, welding current and welding speed. Taguchi's analysis technique has been applied to optimize the process parameters; the response values for analysis are yield strength and micro-hardness. The test results showed that with the application of the vibratory treatment the values of hardness and tensile properties increased. The auxiliary vibrations induced into the weld pool resulted in increased micro-hardness of the weld metal which indicates the orientation of the crystal and refinement of grains took place. This study shows that vibration applied into the weld pool can be successfully improved the mechanical properties of welded joints. Thus this research attempt provided an alternative welding technique for grain refinement of weldments.

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

    Science.gov (United States)

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

    1989-01-01

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

  2. 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

  3. Thermoplastic welding apparatus and method

    Science.gov (United States)

    Matsen, Marc R.; Negley, Mark A.; Geren, William Preston; Miller, Robert James

    2017-03-07

    A thermoplastic welding apparatus includes a thermoplastic welding tool, at least one tooling surface in the thermoplastic welding tool, a magnetic induction coil in the thermoplastic welding tool and generally encircling the at least one tooling surface and at least one smart susceptor in the thermoplastic welding tool at the at least one tooling surface. The magnetic induction coil is adapted to generate a magnetic flux field oriented generally parallel to a plane of the at least one smart susceptor.

  4. Laser forming and welding processes

    CERN Document Server

    Yilbas, Bekir Sami; Shuja, Shahzada Zaman

    2013-01-01

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

  5. Physical characteristics of welding arc ignition process

    Science.gov (United States)

    Shi, Linan; Song, Yonglun; Xiao, Tianjiao; Ran, Guowei

    2012-07-01

    The existing research of welding arc mainly focuses on the stable combustion state and the research on the mechanism of welding arc ignition process is quite lack. The tungsten inert gas(TIG) touch arc ignition process is observed via a high speed camera and the high time resolution spectral diagnosis system. The changing phenomenon of main ionized element provided the electrons in the arc ignition is found. The metallic element is the main contributor to provide the electrons at the beginning of the discharging, and then the excitated shielding gas element replaces the function of the metallic element. The electron density during the period of the arc ignition is calculated by the Stark-broadened lines of Hα. Through the discussion with the repeatability in relaxation phenomenon, the statistical regularity in the arc ignition process is analyzed. The similar rules as above are observed through the comparison with the laser-assisted arc ignition experiments and the metal inert gas(MIG) arc ignition experiments. This research is helpful to further understanding on the generation mechanism of welding arc ignition and also has a certain academic and practical significance on enriching the welding physical theoretical foundation and improving the precise monitoring on automatic arc welding process.

  6. Translating formative research findings into a behaviour change strategy to promote antenatal calcium and iron and folic acid supplementation in western Kenya.

    Science.gov (United States)

    Martin, Stephanie L; Seim, Gretchen L; Wawire, Salome; Chapleau, Gina M; Young, Sera L; Dickin, Katherine L

    2017-01-01

    The World Health Organization now recommends integrating calcium supplements into antenatal micronutrient supplementation programmes to prevent pre-eclampsia, a leading cause of maternal mortality. As countries consider integrating calcium supplementation into antenatal care (ANC), it is important to identify context-specific barriers and facilitators to delivery and adherence. Such insights can be gained from women's and health workers' experiences with iron and folic acid (IFA) supplements. We conducted in-depth interviews with 22 pregnant and post-partum women and 20 community-based and facility-based health workers in Kenya to inform a calcium and IFA supplementation programme. Interviews assessed awareness of anaemia, pre-eclampsia and eclampsia; ANC attendance; and barriers and facilitators to IFA supplement delivery and adherence. We analyzed interviews inductively using the constant comparative method. Women and health workers identified poor diet quality in pregnancy as a major health concern. Neither women nor health workers identified pre-eclampsia, eclampsia, anaemia or related symptoms as serious health threats. Women and community-based health workers were unfamiliar with pre-eclampsia and eclampsia and considered anaemia symptoms normal. Most women had not received IFA supplements, and those who had received insufficient amounts and little information about supplement benefits. We then developed a multi-level (health facility, community, household and individual) behaviour change strategy to promote antenatal calcium and IFA supplementation. Formative research is an essential first step in guiding implementation of antenatal calcium supplementation programmes to reduce pre-eclampsia. Because evidence on how to implement successful calcium supplementation programmes is limited, experiences with antenatal IFA supplementation can be used to guide programme development. © 2016 John Wiley & Sons Ltd.

  7. Low temperature impact testing of welded structural wrought iron

    Science.gov (United States)

    Rogers, Zachary

    During the second half of the 19th century, structural wrought iron was commonly used in construction of bridges and other structures. Today, these remaining structures are still actively in use and may fall under the protection of historic preservation agencies. Continued use and protection leads to the need for inspection, maintenance, and repair of the wrought iron within these structures. Welding can be useful to achieve the appropriate repair, rehabilitation, or replacement of wrought iron members. There is currently very little published on modern welding techniques for historic wrought iron. There is also no pre-qualified method for this welding. The demand for welding in the repair of historic structural wrought iron has led to a line of research investigating shielded metal arc welding (SMAW) of historic wrought iron at the University of Colorado Denver. This prior research selected the weld type and other weld specifications to try and achieve a recognized specific welding procedure using modern SMAW technology and techniques. This thesis continues investigating SMAW of historic wrought iron. Specifically, this thesis addresses the toughness of these welds from analysis of the data collected from performing Charpy V-Notch (CVN) Impact Tests. Temperature was varied to observe the material response of the welds at low temperature. The wrought iron used in testing was from a historic vehicle bridge in Minnesota, USA. This area, and many other areas with wrought iron structures, can experience sustained or fluctuating temperatures far below freezing. Investigating the toughness of welds in historic wrought iron at these temperatures is necessary to fully understand material responses of the existing structures in need of maintenance and repair. It was shown that welded wrought iron is tougher and more ductile than non-welded wrought iron. In regards to toughness, welding is an acceptable repair method. Information on wrought iron, low temperature failure

  8. Effect of Strength Matching on Mechanical Properties of WELDOX 960 Steel Welded Joint

    Science.gov (United States)

    Wang, Zhiling

    2017-10-01

    In this paper, WELDOX 960 high strength steel sheet was used as the research object, and the welding method was adopted with Ar-CO2 mixed gas welding method. The change of microstructure and properties under different strength matching was studied by changing the strength matching method of welded joint. The main research contents are as follows: The comprehensive mechanical properties of the weld are tested, including the tensile, impact and microhardness tests. The changes of the comprehensive mechanical properties of the welds under different strength matching are obtained, and the selection of the best strength matching under different application conditions is put forward.

  9. Welding processes handbook

    CERN Document Server

    Weman, Klas

    2003-01-01

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

  10. Thermal stir welding process

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2012-01-01

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

  11. Thermal stir welding apparatus

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2011-01-01

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

  12. Solar array welding developement

    Science.gov (United States)

    Elms, R. V., Jr.

    1974-01-01

    The present work describes parallel gap welding as used for joining solar cells to the cell interconnect system. Sample preparation, weldable cell parameter evaluation, bond scheduling, bond strength evaluation, and bonding and thermal shock tests are described. A range of weld schedule parameters - voltage, time, and force - can be identified for various cell/interconnect designs that will provide adequate bond strengths and acceptably small electrical degradation. Automation of solar array welding operations to a significant degree has been achieved in Europe and will be receiving increased attention in the U.S. to reduce solar array fabrication costs.

  13. Review of Welding Terminology

    Directory of Open Access Journals (Sweden)

    Angelika Petrėtienė

    2011-04-01

    Full Text Available The paper discusses welding terms in accordance with the Lithuanian standard LST EN 1792 „Welding. The multilingual list of welding terms and similar processes”, „The Russian–Lithuanian dictionary of the terms of mechanical engineering technology and welding“ and the examples from postgraduates‘ final works. It analyses the infringement of lexical, word-building and morphological rules. First-year students should already be familiar with the standardized terms of their speciality. More active propagation of the terms should help to avoid terminology mistakes in various scientific spheres.

  14. 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...

  15. The development of a quality prediction system for aluminum laser welding to measure plasma intensity using photodiodes

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Ji Young [Technical Research Center, Hyundai Steel Company, Dangjin (Korea, Republic of); Sohn, Yong Ho [Dept. of Materials Science and Engineering, University of Central Florida, Orlando (United States); Park, Young Whan; Kwak, Jae Seob [Dept. of Mechanical Engineering, Pukyong National University, Busan (Korea, Republic of)

    2016-10-15

    Lightweight metals have been used to manufacture the body panels of cars to reduce the weight of car bodies. Typically, aluminum sheets are welded together, with a focus on weld quality assurance. A weld quality prediction system for the laser welding of aluminum was developed in this research to maximize welding production. The behavior of the plasma was also analyzed, dependent on various welding conditions. The light intensity of the plasma was altered with heat input and wire feed rate conditions, and the strength of the weld and sensor signals correlated closely for this heat input condition. Using these characteristics, a new algorithm and program were developed to evaluate the weld quality. The design involves a combinatory algorithm using a neural network model for the prediction of tensile strength from measured signals and a fuzzy multi-feature pattern recognition algorithm for the weld quality classification to improve predictability of the system.

  16. Multispot fiber laser welding

    DEFF Research Database (Denmark)

    Schutt Hansen, Klaus

    This dissertation presents work and results achieved in the field of multi beam fiber laser welding. The project has had a practical approach, in which simulations and modelling have been kept at a minimum. Different methods to produce spot patterns with high power single mode fiber lasers have...... been examined and evaluated. It is found that both diamond turned DOE’s in zinc sulphide and multilevel etched DOE’s (Diffractive Optical Elements) in fused silica have a good performance. Welding with multiple beams in a butt joint configuration has been tested. Results are presented, showing it has...... been possible to control the welding width in incremental steps by adding more beams in a row. The laser power was used to independently control the keyhole and consequently the depth of fusion. An example of inline repair of a laser weld in butt joint configuration was examined. Zinc powder was placed...

  17. Friction stir welding tool

    Science.gov (United States)

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

    2008-04-15

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

  18. Metal flow of a tailor-welded blank in deep drawing process

    Science.gov (United States)

    Yan, Qi; Guo, Ruiquan

    2005-01-01

    Tailor welded blanks were used in the automotive industry to consolidate parts, reduce weight, and increase safety. In recent years, this technology was developing rapidly in China. In Chinese car models, tailor welded blanks had been applied in a lot of automobile parts such as rail, door inner, bumper, floor panel, etc. Concerns on the properties of tailor welded blanks had become more and more important for automobile industry. A lot of research had shown that the strength of the welded seam was higher than that of the base metal, such that the weld failure in the aspect of strength was not a critical issue. However, formability of tailor welded blanks in the stamping process was complex. Among them, the metal flow of tailor welded blanks in the stamping process must be investigated thoroughly in order to reduce the scrap rate during the stamping process in automobile factories. In this paper, the behavior of metal flow for tailor welded blanks made by the laser welding process with two types of different thickness combinations were studied in the deep drawing process. Simulations and experiment verification of the movement of weld line for tailor welded blanks were discussed in detail. Results showed that the control on the movement of welded seam during stamping process by taking some measures in the aspect of blank holder was effective.

  19. Effect of Multipass TIG and Activated TIG Welding Process on the Thermo-Mechanical Behavior of 316LN Stainless Steel Weld Joints

    Science.gov (United States)

    Ganesh, K. C.; Balasubramanian, K. R.; Vasudevan, M.; Vasantharaja, P.; Chandrasekhar, N.

    2016-04-01

    The primary objective of this work was to develop a finite element model to predict the thermo-mechanical behavior of an activated tungsten inert gas (ATIG)-welded joint. The ATIG-welded joint was fabricated using 10 mm thickness of 316LN stainless steel plates in a single pass. To distinguish the merits of ATIG welding process, it was compared with manual multipass tungsten inert gas (MPTIG)-welded joint. The ATIG-welded joint was fabricated with square butt edge configuration using an activating flux developed in-house. The MPTIG-welded joint was fabricated in thirteen passes with V-groove edge configuration. The finite element model was developed to predict the transient temperature, residual stress, and distortion of the welded joints. Also, microhardness, impact toughness, tensile strength, ferrite measurement, and microstructure were characterized. Since most of the recent publications of ATIG-welded joint was focused on the molten weld pool dynamics, this research work gives an insight on the thermo-mechanical behavior of ATIG-welded joint over MPTIG-welded joint.

  20. Concurrent ultrasonic weld evaluation system

    Science.gov (United States)

    Hood, Donald W.; Johnson, John A.; Smartt, Herschel B.

    1987-01-01

    A system for concurrent, non-destructive evaluation of partially completed welds for use in conjunction with an automated welder. The system utilizes real time, automated ultrasonic inspection of a welding operation as the welds are being made by providing a transducer which follows a short distance behind the welding head. Reflected ultrasonic signals are analyzed utilizing computer based digital pattern recognition techniques to discriminate between good and flawed welds on a pass by pass basis. The system also distinguishes between types of weld flaws.

  1. Mechanical Behaviour Investigation Of Aluminium Alloy Tailor Welded Blank Developed By Using Friction Stir Welding Technique

    Science.gov (United States)

    Dwi Anggono, Agus; Sugito, Bibit; Hariyanto, Agus; Subroto; Sarjito

    2017-10-01

    The objective on the research was to investigate the mechanical properties and microstructure of tailor welded blank (TWB) made from AA6061-T6 and AA1100 using friction stir welding (FSW) process. Due to the dissimilar mechanical properties of the two aluminium alloys, microhardness test was conducted to measure the hardness distribution across the weld nugget. The mixing of two distinct materials was influenced by tool rotation speed. Therefore, microstructure analysis was carried out to investigate the grain size and shape. The grain size of AA6061-T6 has increased in the heat affected zone (HAZ) while for AA1100 has decreased. In the weld nugget, it has found a hook defects in the dissimilar aluminium joining. By using monotonic tensile load, the different weld line direction was observed with the expansion in tool rotation. The joints failure were consistently on the area of AA1100 series. Furthermore, two specimens were investigated, one through the dissimilar aluminium and the other through similiar material. Inspection of the weld nugget hardness was shown that nonhomogen material intermixing during the stiring process as confirmed by microhardness measurement.

  2. Experimental investigation of the thickness effect for large as-welded SAW S355 steel specimens

    DEFF Research Database (Denmark)

    Ólafsson, Ólafur Magnús; Jensen, Jørgen Juncher; Berggreen, Christian

    2016-01-01

    The presented work aims to investigate and establish a pre-cise, thorough and detailed database from series of experi-mental testing of submerged arc welded (SAW) specimens of various thicknesses typically applied in ships and offshore structures and foundations. Welded structures of all sizes...... and shapes exhibit fatigue failure primarily in the welded region, rather than in the base material, due to imperfections and flaws relating to the welding procedure. The welded region has therefore received much attention from universities, re-search institutions along with industry as it is of significant...

  3. Pin Tool Geometry Effects in Friction Stir Welding

    Science.gov (United States)

    Querin, J. A.; Rubisoff, H. A.; Schneider, J. A.

    2009-01-01

    In friction stir welding (FSW) there is significant evidence that material can take one of two different flow paths when being displaced from its original position in front of the pin tool to its final position in the wake of the weld. The geometry of the pin tool, along with the process parameters, plays an important role in dictating the path that the material takes. Each flow path will impart a different thermomechanical history on the material, consequently altering the material microstructure and subsequent weld properties. The intention of this research is to isolate the effect that different pin tool attributes have on the flow paths imparted on the FSWed material. Based on published weld tool geometries, a variety of weld tools were fabricated and used to join AA2219. Results from the tensile properties and microstructural characterization will be presented.

  4. Metal arc welding and the risk of skin cancer

    DEFF Research Database (Denmark)

    Heltoft, K N; Slagor, R M; Agner, T

    2017-01-01

    OBJECTIVES: Arc welding produces the full spectrum of ultraviolet radiation and may be a contributory cause of skin cancer; however, there has been little research into this occupational hazard. The aim of this study is to explore if metal arc welding increases the risk of malignant melanoma and...... >30 years (n = 5). No statistically significant difference was observed for SCC. The risk of CMM at the neck was also significantly elevated after 30 years of welding, but this is based upon only one exposed case. CONCLUSION: This study indicates that long-term exposure to metal arc welding may...... be related to increased risk of BCC and AK located exclusively at the neck. The study provides no support for the hypothesis that welding exposure increases the risk for skin cancer at other locations....

  5. Heat flow in variable polarity plasma arc welds

    Science.gov (United States)

    Abdelmessih, Amanie N.

    1992-01-01

    The space shuttle external tank and the space station Freedom are fabricated by the variable polarity plasma arc (VPPA) welding. Heat sink effects (taper) are observed when there are irregularities in the work-piece configuration especially if these irregularities are close to the weld bead. These heat sinks affect the geometry of the weld bead, and in extreme cases they could cause defects such as incomplete fusion. Also, different fixtures seem to have varying heat sink effects. The objective of the previous, present, and consecutive research studies is to investigate the effect of irregularities in the work-piece configuration and fixture differences on the weld bead geometry with the ultimate objective to compensate automatically for the heat sink effects and achieve a perfect weld.

  6. Ultra fine particles from the welding process; Hitsaamon pienhiukkaset - HIPHI

    Energy Technology Data Exchange (ETDEWEB)

    Haenninen, H.; Kasurinen, H. [Helsinki Univ. of Technology, Otaniemi (Finland). Laboratory of Engineering Materials

    2004-07-01

    The objects of the project are to research ultra fine particles developed in the welding and cutting processes, to classify the particles in the welding fume, as well as to assess how they transform in air and drift in internal air. Also will be attempted to decrease the amount of ultra fine particles in welding processes and in internal air. Experiments will be performed in the laboratory environments so that the results are valid and comparable. The fine particles in the fumes will be measured and sampled by cascade impactors (ELPI, DLPI) and by SMPS by filter samplers (personal and area). The composition, size, shape and activity of the particles will be determined. During the project both personal welding helmets and fume extraction welding guns will be tested. Tests will be carried out in the laboratory and in industrial workshops. The three-year project started in the beginning of February 2003. (orig.)

  7. Life time assessment and repair of dissimilar metal welds. Part 1; Livslaengdsbedoemning och reparation av blandsvetsskarvar. Etapp 1

    Energy Technology Data Exchange (ETDEWEB)

    Storesund, Jan; Borggreen, Kjeld

    2005-04-01

    Research on the performance of dissimilar metal welds in high temperature plant has been performed for many years. Nevertheless damages are frequent in such welds. In order to decrease the damage problems and make it possible to estimate residual lifetimes of dissimilar metal welds in our Nordic countries it is first essential to i) collect the knowledge in the literature and ii) map current dissimilar metal welds and their condition in Swedish and Danish plants. The present report describes this first part of the work. There is a comprehensive literature of she subject. Most work has been performed on ferritic/austenitic dissimilar welds. In Swedish and Danish plants the dominating type is ferritic/martensitic dissimilar welds. The damage mechanisms are about the same in the two types, creep is the dominating mechanism, but plant experience indicates that the ferritic/austenitic combination is more prone to damage than the ferritic/martensitic one. An important difference between the two types is that Ni-base weld metal generally prolongs the lifetime for ferritic/austenitic dissimilar welds whereas it shows an opposite effect in ferritic/martensitic ones. In the latter case use of a 5 % Cr weld metal seems to be the best choice but the experiences of such welds are limited. The mapping of dissimilar welds indicates that there are predominantly special kinds of welds which fail whereas ordinary butt welds and branch welds are relatively free from damage.

  8. Masquelier's grape seed extract: from basic flavonoid research to a well-characterized food supplement with health benefits.

    Science.gov (United States)

    Weseler, Antje R; Bast, Aalt

    2017-01-19

    Careful characterization and standardization of the composition of plant-derived food supplements is essential to establish a cause-effect relationship between the intake of that product and its health effect. In this review we follow a specific grape seed extract containing monomeric and oligomeric flavan-3-ols from its creation by Jack Masquelier in 1947 towards a botanical remedy and nutraceutical with proven health benefits. The preparation's research history parallels the advancing insights in the fields of molecular biology, medicine, plant and nutritional sciences during the last 70 years. Analysis of the extract's flavanol composition emerged from unspecific colorimetric assays to precise high performance liquid chromatography - mass spectrometry and proton nuclear magnetic resonance fingerprinting techniques. The early recognition of the preparation's auspicious effects on the permeability of vascular capillaries directed research to unravel the underlying cellular and molecular mechanisms. Recent clinical data revealed a multitude of favorable alterations in the vasculature upon an 8 weeks supplementation which summed up in a health benefit of the extract in healthy humans. Changes in gene expression of inflammatory pathways in the volunteers' leukocytes were suggested to be involved in this benefit. The historically grown scientific evidence for the preparation's health effects paves the way to further elucidate its metabolic fate and molecular action in humans.

  9. Carbohydrate supplementation and prolonged intermittent high-intensity exercise in adolescents: research findings, ethical issues and suggestions for the future.

    Science.gov (United States)

    Phillips, Shaun M

    2012-10-01

    In the last decade, research has begun to investigate the efficacy of carbohydrate supplementation for improving aspects of physical capacity and skill performance during sport-specific exercise in adolescent team games players. This research remains in its infancy, and further study would be beneficial considering the large youth population actively involved in team games. Literature on the influence of carbohydrate supplementation on skill performance is scarce, limited to shooting accuracy in adolescent basketball players and conflicting in its findings. Between-study differences in the exercise protocol, volume of fluid and carbohydrate consumed, use of prior fatiguing exercise and timing of skill tests may contribute to the different findings. Conversely, initial data supports carbohydrate supplementation in solution and gel form for improving intermittent endurance running capacity following soccer-specific shuttle running. These studies produced reliable data, but were subject to limitations including lack of quantification of the metabolic response of participants, limited generalization of data due to narrow participant age and maturation ranges, use of males and females within the same sample and non-standardized pre-exercise nutritional status between participants. There is a lack of consensus regarding the influence of frequently consuming carbohydrate-containing products on tooth enamel erosion and the development of obesity or being overweight in adolescent athletes and non-athletes. These discrepancies mean that the initiation or exacerbation of health issues due to frequent consumption of carbohydrate-containing products by adolescents cannot be conclusively refuted. Coupled with the knowledge that consuming a natural, high-carbohydrate diet -3-8 hours before exercise can significantly alter substrate use and improve exercise performance in adults, a moral and ethical concern is raised regarding the direction of future research in order to further

  10. Weld formation control at electron beam welding with beam oscillations

    OpenAIRE

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

    2014-01-01

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

  11. Novel Optimization Methodology for Welding Process/Consumable Integration

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-01-15

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

  12. Experimental assessment of the influence of welding process parameters on Lamb wave transmission across ultrasonically welded thermoplastic composite joints

    Science.gov (United States)

    Ochôa, Pedro; Fernandez Villegas, Irene; Groves, Roger M.; Benedictus, Rinze

    2018-01-01

    One of the advantages of thermoplastic composites relative to their thermoset counterparts is the possibility of assembling components through welding. Ultrasonic welding in particular is very promising for industrialization. However, uncertainty in the fatigue and fracture behaviour of composites is still an obstacle to the full utilisation of these materials. Health monitoring is then of vital importance, and Lamb wave techniques have been widely recognised as some of the most promising approaches for that end. This paper presents the first experimental study about the influence of welding travel on the transmission of Lamb waves across ultrasonically welded thermoplastic composite joints in single-lap configuration. The main aim of this research is to start to understand how guided waves interact with the internal structure of ultrasonic welds, so that benign, manufacturing-related structural features can be distinguished from damaging ones in signal interpretation. The power transmission coefficient and the correlation coefficient proved to be suitable for analysing the wave propagation phenomena, allowing quantitative identification of small variations of weld-line thickness and intermolecular diffusion at the weld interface. The conclusions are used to develop a tentative damage detection criterion which can later on assist the design of a Lamb wave based structural health monitoring system for thermoplastic composite structures. The Lamb wave test results are backed up by phased-array inspections, which also provide some extra insight on the internal structure of ultrasonic welds.

  13. Alternate Welding Processes for In-Service Welding

    Science.gov (United States)

    2009-04-24

    Conducting weld repairs and attaching hot tap tees onto pressurized pipes has the advantage of avoiding loss of service and revenue. However, the risks involved with in-service welding need to be managed by ensuring that welding is performed in a rep...

  14. Certification of a weld produced by friction stir welding

    Science.gov (United States)

    Obaditch, Chris; Grant, Glenn J

    2013-10-01

    Methods, devices, and systems for providing certification of friction stir welds are disclosed. A sensor is used to collect information related to a friction stir weld. Data from the sensor is compared to threshold values provided by an extrinsic standard setting organizations using a certification engine. The certification engine subsequently produces a report on the certification status of the weld.

  15. Welding defects at friction stir welding

    Directory of Open Access Journals (Sweden)

    P. Podržaj

    2015-04-01

    Full Text Available The paper presents an overview of different types of defects at friction stir welding. In order to explain the reasons for their occurrence a short theoretical background of the process is given first. The main emphasis is on the parameters that influence the process. An energy supply based division of defects into three disjoint groups was used. The occurring defects are demonstrated on various materials.

  16. Workmanship standards for fusion welding

    Science.gov (United States)

    Phillips, M. D.

    1967-01-01

    Workmanship standards manual defines practices, that adhere to rigid codes and specifications, for fusion welding of component piping, assemblies, and systems. With written and pictorial presentations, it is part of the operating procedure for fusion welding.

  17. Welding and Brazing Silicon Carbide

    Science.gov (United States)

    Moore, T. J.

    1986-01-01

    Hot isostatic pressing and conventional furnace brazing effective under right conditions. Study performed showed feasibility of welding SiC using several welding and brazing techniques. Use of SiC improves engine efficiency by allowing increase in operating temperature. SiC successfully hot-pressure-welded at 3,550 degrees F (1,950 degrees C) in argon. Refinements of solid-state welding and brazing procedures used sufficient for some specific industrial applications.

  18. Hybrid/Tandem Laser-Arc Welding of Thick Low Carbon Martensitic Stainless Steel Plates =

    Science.gov (United States)

    Mirakhorli, Fatemeh

    High efficiency and long-term life of hydraulic turbines and their assemblies are of utmost importance for the hydropower industry. Usually, hydroelectric turbine components are made of thick-walled low carbon martensitic stainless steels. The assembly of large hydroelectric turbine components has been a great challenge. The use of conventional welding processes involves typical large groove design and multi-pass welding to fill the groove which exposes the weld to a high heat input creating relatively large fusion zone and heat affected zone. The newly-developed hybrid/tandem laser-arc welding technique is believed to offer a highly competitive solution to improve the overall hydro-turbine performance by combining the high energy density and fast welding speed of the laser welding technology with the good gap bridging and feeding ability of the gas metal arc welding process to increase the productivity and reduce the consumable material. The main objective of this research work is to understand different challenges appearing during hybrid laser-arc welding (HLAW) of thick gauge assemblies of low carbon 13%Cr- 4%Ni martensitic stainless steel and find a practical solution by adapting and optimizing this relatively new welding process in order to reduce the number of welding passes necessary to fill the groove gap. The joint integrity was evaluated in terms of microstructure, defects and mechanical properties in both as-welded and post-welded conditions. A special focus was given to the hybrid and tandem laser-arc welding technique for the root pass. Based on the thickness of the low carbon martensitic stainless steel plates, this work is mainly focused on the following two tasks: • Single pass hybrid laser-arc welding of 10-mm thick low carbon martensitic stainless steel. • Multi-pass hybrid/tandem laser-arc welding of 25-mm thick martensitic stainless steel.

  19. 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

  20. [A tentative research of testosterone supplement therapy on male senile dementia].

    Science.gov (United States)

    Li, Hong-Jun; Zhou, Bao-Lin; Bai, Li-Li; Liu, Jun-Sheng; Huang, Yu-Feng

    2003-06-01

    To understand the hormone levels in male senile dementia patients and the effects of testosterone supplement theraphy (TST) on male senile dementia. The general health condition, mental health condition, hormone levels, and some other aspects were evaluated in 9 patients with male senile dementia without significant contradiction for TST. 9 patients were treated with oral testosterone undecanoate 120 mg per day for six weeks, and relative changes were observed, detected and recorded. In 9 cases of male senile dementia, the average score was 5.33 in mini-mental state examination (MMSE), 14.56 in Hamilton depression scale (HAMD), 5.0 in geriatric depression scale (GDS), 32.56 in partial androgen deficiency of the aging male (PADAM) measuring form. The volume of testis was small (8.33 ml on average). After 1 week of having finished TST, the levels of serum testosterone (T) dropped significantly (dropped from average 2.88 ng/ml to 2.47 ng/ml, P Physical strength and psychological status improved significantly, but vasomotor symptoms and sexual function failed response to the treatment. The levels of androgen is low, and the symptoms of androgen deficiency are readily seen in male senile dementia. TST can improve life quality of most patients to some extent.

  1. Investigation on edge joints of Inconel 625 sheets processed with laser welding

    Science.gov (United States)

    Caiazzo, F.; Alfieri, V.; Cardaropoli, F.; Sergi, V.

    2017-08-01

    Laser welding of Inconel 625 edge joint beads in square groove configuration was investigated. The use of different weld geometries in new aerospace solutions explains research on edge joints. A structured plan was carried out in order to characterize the process defining the influence of laser power and welding speed and to study possible interactions among the governing factors. As weld pool protection is crucial in order to obtain sound joints when processing superalloys, a special glove box for gas supply was designed to upgrade the welding head. Welded joints were characterized referring to bead profile, microstructure and X-rays. It was found that heat input plays an important role as it affects welding stability, porosity content and bead shape. Results suggest operating with low values of heat input to reduce porosity and guarantee stable bead conformation. Furthermore, a decrease in the grain size has been observed as a consequence of decreasing heat input.

  2. Statistical modeling of laser welding of DP/TRIP steel sheets

    Science.gov (United States)

    Reisgen, U.; Schleser, M.; Mokrov, O.; Ahmed, E.

    2012-02-01

    In this research work, a statistical analysis of the CO 2 laser beam welding of dual phase (DP600)/transformation induced plasticity (TRIP700) steel sheets was done using response surface methodology. The analysis considered the effect of laser power (2-2.2 kW), welding speed (40-50 mm/s) and focus position (-1 to 0 mm) on the heat input, the weld bead geometry, uniaxial tensile strength, formability limited dome height and welding operation cost. The experimental design was based on Box-Behnken design using linear and quadratic polynomial equations for predicting the mathematical models. The results indicate that the proposed models predict the responses adequately within the limits of welding parameters being used and the welding speed is the most significant parameter during the welding process.

  3. Emission of dust and gases in tubular cored wire welding of steel.

    Science.gov (United States)

    Matusiak, Jolanta; Rams, Beata

    2003-01-01

    The emission of dusts and gases, which are generated during tubular cored wire welding and which are hazardous to health and the environment, were studied. Tests included various kinds of tubular electrode wires used for welding steel, that is, rutile flux cored wires, basic flux cored wires, and metal cored wires for welding unalloyed, low-alloy, and high-alloy steels as well as self-shielded flux cored wires used for welding low-alloy steels. The research results make it possible to assess the influence of the type of wire and welding conditions on the emission volume and to compare chemical hazards generated during tubular cored wire welding with those typical for other arc welding processes.

  4. Welding. Performance Objectives. Basic Course.

    Science.gov (United States)

    Vincent, Kenneth

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

  5. Welding. Performance Objectives. Intermediate Course.

    Science.gov (United States)

    Vincent, Kenneth

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

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

    Science.gov (United States)

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

    2013-05-07

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

  7. Ultrasonic Evaluation of Weld Strength for Aluminum Ultrasonic Spot Welds

    Science.gov (United States)

    Ghaffari, Bita; Hetrick, Elizabeth T.; Mozurkewich, George; Reatherford, Larry V.

    2005-04-01

    The goal of this work is to determine the feasibility of using an ultrasonic, non-destructive technique for post-process evaluation of aluminum ultrasonic spot welds. A focused immersion transducer was utilized to obtain a C-scan of the weld interface, from which a weighted ultrasonic contact area was estimated. Weldments were subsequently tested destructively to determine the weld strength. The square root of the weld contact area displayed a relatively good correlation with weld strength, r2=0.85.

  8. Metal Cutting Theory and Friction Stir Welding Tool Design

    Science.gov (United States)

    Payton, Lewis N.

    2003-01-01

    Friction Stir Welding (FSW) is a relatively new industrial process that was invented at The Weld Institute (TWI, United Kingdom) and patented in 1992 under research funded by in part by the National Aeronautics and Space Administration (NASA). Often quoted advantages of the process include good strength and ductility along with minimization of residual stress and distortion. Less well advertised are the beneficial effects of this solid state welding process in the field of occupational and environmental safety. It produces superior weld products in difficult to weld materials without producing any toxic fumes or solid waste that must be controlled as hazardous waste. In fact, it reduces noise pollution in the workspace as well. In the early days of FSW, most welding was performed on modified machine tools, in particular on milling machines with modified milling cutters. In spite of the obvious milling heritage of the process, the techniques and lessons learned from almost 250 years of successful metalworking with milling machines have not been applied in the field of modern Friction Stir Welding. The goal of the current research was to study currently successful FSW tools and parameterize the process in such a way that the design of new tools for new materials could be accelerated. Along the way, several successful new tooling designs were developed for current issues at the Marshall Space Flight Center with accompanying patent disclosures

  9. Investigation into Interface Lifting Within FSW Lap Welds

    Energy Technology Data Exchange (ETDEWEB)

    K. S. Miller; C. R. Tolle; D. E. Clark; C. I. Nichol; T. R. McJunkin; H. B. Smartt

    2008-06-01

    Friction stir welding (FSW) is rapidly penetrating the welding market in many materials and applications, particularly in aluminum alloys for transportation applications. As this expansion outside the research laboratory continues, fitness for service issues will arise, and process control and NDE methods will become important determinants of continued growth. The present paper describes research into FSW weld nugget flaw detection within aluminum alloy lap welds. We present results for two types of FSW tool designs: a smooth pin tool and a threaded pin tool. We show that under certain process parameters (as monitored during welding with a rotating dynamometer that measures x, y, z, and torque forces) and tooling designs, FSW lap welds allow significant nonbonded interface lifting of the lap joint, while forming a metallurgical bond only within the pin region of the weld nugget. These lifted joints are often held very tightly together even though unbonded, and might be expected to pass cursory NDE while representing a substantial compromise in joint mechanical properties. The phenomenon is investigated here via radiographic and ultrasonic NDE techniques, with a copper foil marking insert (as described elsewhere) and by the tensile testing of joints. As one would expect, these results show that tool design and process parameters significantly affect plactic flow and this lifted interface. NDE and mechanical strength ramifications of this defect are discussed.

  10. Weld bead profile of laser welding dissimilar joints stainless steel

    Science.gov (United States)

    Mohammed, Ghusoon R.; Ishak, M.; Aqida, S. N.; Abdulhadi, Hassan A.

    2017-10-01

    During the process of laser welding, the material consecutively melts and solidifies by a laser beam with a peak high power. Several parameters such as the laser energy, pulse frequency, pulse duration, welding power and welding speed govern the mode of the welding process. The aim of this paper is to investigate the effect of peak power, incident angle, and welding speed on the weld bead geometry. The first investigation in this context was conducted using 2205-316L stainless steel plates through the varying of the welding speed from 1.3 mm/s to 2.1 mm/s. The second investigation was conducted by varying the peak power from 1100 W to 1500 W. From the results of the experiments, the welding speed and laser power had a significant effect on the geometry of the weld bead, and the variation in the diameter of the bead pulse-size. Due to the decrease in the heat input, welding speed affected penetration depth more than bead width, and a narrow width of heat affected zone was achieved ranging from 0.2 to 0.5 mm. Conclusively, weld bead geometry dimensions increase as a function of peak power; at over 1350 W peak power, the dimensions lie within 30 μm.

  11. Weld Nugget Temperature Control in Thermal Stir Welding

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2014-01-01

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

  12. Supplement to the technical assessment of geoscience-related research for geothermal energy technology. Final report

    Energy Technology Data Exchange (ETDEWEB)

    1983-09-01

    Detailed information (e.g., project title, sponsoring organization, research area, objective status, etc.) is presented for 338 geoscience/geothermal related projects. A summary of the projects conducted by sponsoring organization is presented and an easy reference to obtain detailed information on the number and type of efforts being sponsored is presented. The projects are summarized by research area (e.g., volcanology, fluid inclusions, etc.) and an additional project cross-reference mechanism is also provided. Subsequent to the collection of the project information, a geosciences classification system was developed to categorize each project by research area (e.g., isotope geochemistry, heat flow studies) and by type of research conducted (e.g., theoretical research, modeling/simulation). A series of matrices is included that summarize, on a project-by-project basis, the research area addressed and the type of R and D conducted. In addition, a summary of the total number of projects by research area and R and D type is given.

  13. Application of welding simulation to block joints in shipbuilding and assessment of welding-induced residual stresses and distortions

    Directory of Open Access Journals (Sweden)

    Fricke Wolfgang

    2014-06-01

    Full Text Available During ship design, welding-induced distortions are roughly estimated as a function of the size of the component as well as the welding process and residual stresses are assumed to be locally in the range of the yield stress. Existing welding simulation methods are very complex and time-consuming and therefore not applicable to large structures like ships. Simplified methods for the estimation of welding effects were and still are subject of several research projects, but mostly concerning smaller structures. The main goal of this paper is the application of a multi-layer welding simulation to the block joint of a ship structure. When welding block joints, high constraints occur due to the ship structure which are assumed to result in accordingly high residual stresses. Constraints measured during construction were realized in a test plant for small-scale welding specimens in order to investigate their and other effects on the residual stresses. Associated welding simulations were successfully performed with fine-mesh finite element models. Further analyses showed that a courser mesh was also able to reproduce the welding-induced reaction forces and hence the residual stresses after some calibration. Based on the coarse modeling it was possible to perform the welding simulation at a block joint in order to investigate the influence of the resulting residual stresses on the behavior of the real structure, showing quite interesting stress distributions. Finally it is discussed whether smaller and idealized models of definite areas of the block joint can be used to achieve the same results offering possibilities to consider residual stresses in the design process.

  14. Application of welding simulation to block joints in shipbuilding and assessment of welding-induced residual stresses and distortions

    Science.gov (United States)

    Fricke, Wolfgang; Zacke, Sonja

    2014-06-01

    During ship design, welding-induced distortions are roughly estimated as a function of the size of the component as well as the welding process and residual stresses are assumed to be locally in the range of the yield stress. Existing welding simulation methods are very complex and time-consuming and therefore not applicable to large structures like ships. Simplified methods for the estimation of welding effects were and still are subject of several research projects, but mostly concerning smaller structures. The main goal of this paper is the application of a multi-layer welding simulation to the block joint of a ship structure. When welding block joints, high constraints occur due to the ship structure which are assumed to result in accordingly high residual stresses. Constraints measured during construction were realized in a test plant for small-scale welding specimens in order to investigate their and other effects on the residual stresses. Associated welding simulations were successfully performed with fine-mesh finite element models. Further analyses showed that a courser mesh was also able to reproduce the welding-induced reaction forces and hence the residual stresses after some calibration. Based on the coarse modeling it was possible to perform the welding simulation at a block joint in order to investigate the influence of the resulting residual stresses on the behavior of the real structure, showing quite interesting stress distributions. Finally it is discussed whether smaller and idealized models of definite areas of the block joint can be used to achieve the same results offering possibilities to consider residual stresses in the design process.

  15. A Research Elective Course on Dietary Supplements to Engage Doctor of Pharmacy Students in Primary Literature Evaluation and Scholarly Activity.

    Science.gov (United States)

    Islam, Mohammed A; Gunaseelan, Simi; Khan, Seher A

    2015-12-01

    To develop and implement a research elective course to enhance skills of pharmacy students on primary literature evaluation and evidence-based practice on dietary supplements and generate scholarly publications. A 2 credit hour independent research elective course was designed and implemented in the third-year doctor of pharmacy curriculum. The course involved student-led research activities that included formulating research project, reviewing of primary literature, collection and evaluation of data, and writing of review articles for publication in peer-reviewed journals. An online survey was administered to evaluate students' perceptions of the course. Students successfully completed the course. The course resulted in peer-reviewed publications through student-faculty collaboration. Pharmacy students enrolled in the elective course perceived that the course helped them enhance their analytical reasoning, critical thinking and drug-literature evaluation skills, gain evidence-based knowledge, and apply the knowledge into practice during their advanced pharmacy practice experiences community pharmacy rotations. The course provided opportunity to the pharmacy students to not only critically search and evaluate the literature but also publish in peer-reviewed journals. Other pharmacy schools/colleges can adopt this course model to create opportunities for student-faculty collaborations toward scholarly accomplishments. © The Author(s) 2014.

  16. Numerical simulation of welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær; Thorborg, Jesper

    Aim of project:To analyse and model the transient thermal field from arc welding (SMAW, V-shaped buttweld in 15mm plate) and to some extend the mechanical response due to the thermal field. - To implement this model in a general purpose finite element program such as ABAQUS.The simulation...... stress is also taken into account.Work carried out:With few means it is possible to define a thermal model which describes the thermal field from the welding process in reasonable agreement with reality. Identical results are found with ABAQUS and Rosenthal’s analytical solution of the governing heat...... transfer equation under same conditions. It is relative easy tointroduce boundary conditions such as convection and radiation where not surprisingly the radiation has the greatest influence especially from the high temperature regions in the weld pool and the heat affected zone.Due to the large temperature...

  17. Extravehicular activity welding experiment

    Science.gov (United States)

    Watson, J. Kevin

    1989-01-01

    The In-Space Technology Experiments Program (INSTEP) provides an opportunity to explore the many critical questions which can only be answered by experimentation in space. The objective of the Extravehicular Activity Welding Experiment definition project was to define the requirements for a spaceflight experiment to evaluate the feasibility of performing manual welding tasks during EVA. Consideration was given to experiment design, work station design, welding hardware design, payload integration requirements, and human factors (including safety). The results of this effort are presented. Included are the specific objectives of the flight test, details of the tasks which will generate the required data, and a description of the equipment which will be needed to support the tasks. Work station requirements are addressed as are human factors, STS integration procedures and, most importantly, safety considerations. A preliminary estimate of the cost and the schedule for completion of the experiment through flight and postflight analysis are given.

  18. Pulsed welding plasma source

    Science.gov (United States)

    Knyaz'kov, A.; Pustovykh, O.; Verevkin, A.; Terekhin, V.; Shachek, A.; Tyasto, A.

    2016-04-01

    It is shown that in order to form the current pulse of a near rectangular shape, which provides conversion of the welding arc into a dynamic mode, it is rational to connect a forming element made on the basis of an artificial forming line in series to the welding DC circuit. The paper presents a diagram of a pulsed device for welding with a non-consumable electrode in argon which was developed using the forming element. The conversion of the arc into the dynamic mode is illustrated by the current and voltage oscillograms of the arc gap and the dynamic characteristic of the arc within the interval of one pulse generation time in the arc gap. The background current travels in the interpulse interval.

  19. Immersive Virtual Environment Technology to Supplement Environmental Perception, Preference and Behavior Research: A Review with Applications

    Directory of Open Access Journals (Sweden)

    Jordan W. Smith

    2015-09-01

    Full Text Available Immersive virtual environment (IVE technology offers a wide range of potential benefits to research focused on understanding how individuals perceive and respond to built and natural environments. In an effort to broaden awareness and use of IVE technology in perception, preference and behavior research, this review paper describes how IVE technology can be used to complement more traditional methods commonly applied in public health research. The paper also describes a relatively simple workflow for creating and displaying 360° virtual environments of built and natural settings and presents two freely-available and customizable applications that scientists from a variety of disciplines, including public health, can use to advance their research into human preferences, perceptions and behaviors related to built and natural settings.

  20. Integration and Development in Schizotypy Research: An Introduction to the Special Supplement

    OpenAIRE

    Debbané, Martin; Mohr, Christine

    2015-01-01

    In its fifth decade of existence, the construct of schizotypy is recapturing the early scientific interest it attracted when Paul E. Meehl (1920–2003), who coined the term, pioneered the field of schizotypy research. The International Lemanic Workshop on Schizotypy, hosted at the University of Geneva in December 2013, recently offered an opportunity to address some of the fundamental questions in contemporary schizotypy research and situate the construct in the greater scheme of future scient...

  1. Ternary gas plasma welding torch

    Science.gov (United States)

    Rybicki, Daniel J. (Inventor); Mcgee, William F. (Inventor); Waldron, Douglas J. (Inventor)

    1995-01-01

    A plasma arc welding torch is discussed. A first plasma gas is directed through the body of the welding torch and out of the body across the tip of a welding electrode disposed at the forward end of the body. A second plasma gas is disposed for flow through a longitudinal bore in the electrode. The second plasma gas enters one end of the electrode and exits the electrode at the tip thereof for co-acting with the electric welding arc to produce the desired weld. A shield gas is directed through the torch body and circulates around the head of the torch adjacent to the electrode tip.

  2. The mechanical properties of high speed GTAW weld and factors of nonlinear multiple regression model under external transverse magnetic field

    Science.gov (United States)

    Lu, Lin; Chang, Yunlong; Li, Yingmin; He, Youyou

    2013-05-01

    A transverse magnetic field was introduced to the arc plasma in the process of welding stainless steel tubes by high-speed Tungsten Inert Gas Arc Welding (TIG for short) without filler wire. The influence of external magnetic field on welding quality was investigated. 9 sets of parameters were designed by the means of orthogonal experiment. The welding joint tensile strength and form factor of weld were regarded as the main standards of welding quality. A binary quadratic nonlinear regression equation was established with the conditions of magnetic induction and flow rate of Ar gas. The residual standard deviation was calculated to adjust the accuracy of regression model. The results showed that, the regression model was correct and effective in calculating the tensile strength and aspect ratio of weld. Two 3D regression models were designed respectively, and then the impact law of magnetic induction on welding quality was researched.

  3. Research publications of the H.J. Andrews Experimental Forest, Cascade Range, Oregon: 1988 supplement.

    Science.gov (United States)

    T. Blinn; F.J. Swanson; A. McKee

    1988-01-01

    This bibliography updates the list of publications, abstracts, theses, and unpublished reports included in "Research Publications of the H.J. Andrews Experimental Forest, Cascade Range, Oregon, 1948 to 1986," General Technical Report PNW-GTR-201. Citations are referenced under appropriate keywords.

  4. Evaluation of Using Course-Management Software: Supplementing a Course that Requires a Group Research Project

    Science.gov (United States)

    Korchmaros, Josephine D.; Gump, Nathaniel W.

    2009-01-01

    The benefits of course-management software (CMS) will not be realized if it is underused. The authors investigated one possible barrier to CMS use, students' perceptions of using CMS. After taking a course requiring a group research project, college students reported their perceptions of the use of CMS for the course. Overall, students did not…

  5. Integrated sensors for robotic laser welding

    NARCIS (Netherlands)

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

    2005-01-01

    A welding head is under development with integrated sensory systems for robotic laser welding applications. Robotic laser welding requires sensory systems that are capable to accurately guide the welding head over a seam in three-dimensional space and provide information about the welding process as

  6. Sensor integration for robotic laser welding processes

    NARCIS (Netherlands)

    Iakovou, D.; Aarts, Ronald G.K.M.; Meijer, J.; Ostendorf, A; Hoult, A.; Lu, Y.

    2005-01-01

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

  7. Acoustic-Emission Weld-Penetration Monitor

    Science.gov (United States)

    Maram, J.; Collins, J.

    1986-01-01

    Weld penetration monitored by detection of high-frequency acoustic emissions produced by advancing weld pool as it melts and solidifies in workpiece. Acoustic emission from TIG butt weld measured with 300-kHz resonant transducer. Rise in emission level coincides with cessation of weld penetration due to sudden reduction in welding current. Such monitoring applied to control of automated and robotic welders.

  8. Heat sink effects in variable polarity plasma arc welding

    Science.gov (United States)

    Abdelmessih, Amanie N.

    1991-01-01

    The Space Shuttle External Tank is fabricated by the variable polarity plasma arc (VPPA) welding process. In VPPA welding, a noble gas, usually argon, is directed through an arc to emerge from the torch as a hot plasma jet. This jet is surrounded by a shielding gas, usually helium, to protect the weld from contamination with air. The high velocity, hot plasma jet completely penetrates the workpiece (resembling a line heat source) when operated in the 'keyhole' mode. The metal melts on touching the side of the jet, as the torch travels in the perpendicular direction to the direction of the jet, and melted metal moves around the plasma jet in the keyhole forming a puddle which solidifies behind the jet. Heat sink effects are observed when there are irregularities in the workpiece configuration, especially, if these irregularities are close to the weld bead. These heat sinks affect the geometry of the weld bead, i.e., in extreme cases they could cause defects such as incomplete fusion. Also, different fixtures seem to have varying heat sink effects. The objective of this research is to study the effect of irregularities in workpiece configuration and fixture differences (heat sink effects) on the weld bead geometry with the ultimate objective to compensate for the heat sink effects and achieve a perfect weld. Experiments were performed on different workpiece geometries and compared to approximate models.

  9. Weld procedure development with OSLW - optimization software for laser welding

    Energy Technology Data Exchange (ETDEWEB)

    Fuerschbach, P.W.; Eisler, G.R. [Sandia National Labs., Albuquerque, NM (United States); Steele, R.J. [Naval Air Warfare Center, China Lake, CA (United States)

    1998-06-01

    Weld procedure development can require extensive experimentation, in-depth process knowledge, and is further complicated by the fact that there are often multiple sets of parameters that will meet the weld requirements. Choosing among these multiple weld procedures can be hastened with computer models that find parameters to meet selected weld dimensional requirements while simultaneously optimizing important figures of merit. Software is described that performs this task for CO{sub 2} laser beam welding. The models are based on dimensionless parameter correlations that are derived from solutions to the moving heat source equations. The use of both handbook and empirically verified thermophysical property values allows OSLW to be extended to many different materials. Graphics displays show the resulting solution on contour plots that can be used to further probe the model. The important figures of merit for laser beam welding are energy transfer efficiency and melting efficiency. The application enables the user to input desired weld shape dimensions, select the material to be welded, and to constrain the search problem to meet the application requirements. Successful testing of the software at a laser welding fabricator has validated this tool for weld procedure development.

  10. The influence of metallurgy on the formation of welding aerosols.

    Science.gov (United States)

    Zimmer, Anthony T

    2002-10-01

    Recent research has indicated that insoluble ultrafine aerosols (ie., particles whose physical diameters are less than 100 nm) may cause adverse health effects due to their small size, and that toxicological response may be more appropriately represented by particle number or particle surface area. Unfortunately, current exposure criteria and the associated air-sampling techniques are primarily mass-based. Welding processes are high-temperature operations that generate substantial number concentrations of ultrafine aerosols. Welding aerosols are formed primarily through the nucleation of metal vapors followed by competing growth mechanisms such as coagulation and condensation. Experimental results and mathematical tools are presented to illustrate how welding metallurgy influences the chemical aspects and dynamic processes that initiate and evolve the resultant aerosol. This research suggests that a fundamental understanding of metallurgy and aerosol physics can be exploited to suppress the formation of undesirable chemical species as well as the amount of aerosol generated during a welding process.

  11. Welding. Student Learning Guide.

    Science.gov (United States)

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

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

  12. Thermal Stresses in Welding

    DEFF Research Database (Denmark)

    Hansen, Jan Langkjær

    1998-01-01

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

  13. Elementary TIG Welding Skills.

    Science.gov (United States)

    Pierson, John E., III

    The text was prepared to help deaf students develop the skills needed by an employed welder. It uses simplified language and illustrations to present concepts which should be reinforced by practical experience with welding skills. Each of the 12 lessons contains: (1) an information section with many illustrations which presents a concept or…

  14. Electric pulse treatment of welded joint of aluminum alloy

    OpenAIRE

    A.A. Mitiaev; I. P. Volchok; Yu. L. Nadezhdin; V.A. Sokirko; I. A. Vakulenko

    2013-01-01

    Purpose. Explanation of the redistribution effect of residual strengthes after electric pulse treatment of arc welding seam of the aluminum alloy. Methodology. Alloy on the basis of aluminium of АК8М3 type served as the research material. As a result of mechanical treatment of the ingots after alloy crystallization the plates with 10 mm thickness were obtained. After edge preparation the elements, which are being connected were butt welded using the technology of semiautomatic argon arc weldi...

  15. Solid-State Lighting 2017 Suggested Research Topics Supplement: Technology and Market Context

    Energy Technology Data Exchange (ETDEWEB)

    Pattison, Morgan [Solid State Lighting Services, Inc. SSLS (United States)

    2017-09-29

    A 2017 update to the Solid-State Lighting R&D Plan that is divided into two documents. The first document describes a list of suggested SSL priority research topics and the second document provides context and background, including information drawn from technical, market, and economic studies. Widely referenced by industry and government both here and abroad, these documents reflect SSL stakeholder inputs on key R&D topics that will improve efficacy, reduce cost, remove barriers to adoption, and add value for LED and OLED lighting solutions over the next three to five years, and discuss those applications that drive and prioritize the specific R&D.

  16. Self-Reacting Friction Stir Welding for Aluminum Complex Curvature Applications

    Science.gov (United States)

    Brown, Randy J.; Martin, W.; Schneider, J.; Hartley, P. J.; Russell, Carolyn; Lawless, Kirby; Jones, Chip

    2003-01-01

    This viewgraph representation provides an overview of sucessful research conducted by Lockheed Martin and NASA to develop an advanced self-reacting friction stir technology for complex curvature aluminum alloys. The research included weld process development for 0.320 inch Al 2219, sucessful transfer from the 'lab' scale to the production scale tool and weld quality exceeding strenght goals. This process will enable development and implementation of large scale complex geometry hardware fabrication. Topics covered include: weld process development, weld process transfer, and intermediate hardware fabrication.

  17. Modular Power Supply for Micro Resistance Welding

    Directory of Open Access Journals (Sweden)

    Bondarenko Oleksandr

    2017-07-01

    Full Text Available The study is devoted to the important issue of enhancing the circuitry and characteristics of power supplies for micro resistance welding machines. The aim of the research is to provide high quality input current and to increase the energy efficiency of the output pulse generator by means of improving the circuit topologies of the power supply main blocks. In study, the principle of constructing the power supply for micro resistance welding, which provides high values of output welding current and high accuracy of welding pulse formation, makes it possible to reduce energy losses, and provides high quality of consumed input current, is represented. The multiphase topology of the charger with power factor correction based on SEPIC converters is suggested as the most efficient for charging the supercapacitor storage module. The multicell topology of the supercapacitor energy storage with voltage equalizing is presented. The parameters of the converter cells are evaluated. The calculations of energy efficiency of the power supply’s input and output converters based on suggested topologies are carried out and verified in MATLAB Simulink. The power factor value greater than 99 % is derived.

  18. SHADOW: a new welding technique

    Science.gov (United States)

    Kramer, Thorsten; Olowinsky, Alexander M.; Durand, Friedrich

    2002-06-01

    The new welding technique 'SHADOW ' is introduced. SHADOW means the use of a single pulse to generate a quasi continuous weld of several millimeters in length. HET processing time is defined by the pulse duration of the pulsed laser. At present, a state-of-the-art laser is capable of a maximum pulse duration of 20 ms. The variation of the laser power depend on time is a vital capability of the pulsed laser to adapt the energy deposition into the workpiece. Laser beam welds of several watch components were successfully performed. Similar metals like crowns and axes made out of stainless steel have been welded using pulsed laser radiation. Applying a series of about 130 single pulses for the crown-axis combination the total energy accumulates to 19.5 J. The use of the SHADOW welding technique reduces the energy to 2.5 J. While welding dissimilar metals like stainless steel and bras, the SHADOW welding reduces drastically the contamination as well as the distortion. Laser beam welding of copper has a low process reliability due to the high reflection and the high thermal conductivity. SHADOW welds of 3.6 mm length were performed on 250 micrometers thick copper plates with very high reproducibility. As a result, a pilot plant for laser beam welding of copper plates has been set up. The work to be presented has partly been funded by the European Commission in a project under the contract BRPR-CT-0634.

  19. Prediction of the welding distortion of large steel structure with mechanical restraint using equivalent load methods

    Directory of Open Access Journals (Sweden)

    Jeong-ung Park

    2017-05-01

    Full Text Available The design dimension may not be satisfactory at the final stage due to the welding during the assembly stage, leading to cutting or adding the components in large structure constructions. The productivity is depend on accuracy of the welding quality especially at assembly stage. Therefore, it is of utmost importance to decide the component dimension during each assembly stage considering the above situations during the designing stage by exactly predicting welding deformation before the welding is done. Further, if the system that predicts whether welding deformation is equipped, it is possible to take measures to reduce deformation through FE analysis, helping in saving time for correcting work by arresting the parts which are prone to having welding deformation. For the FE analysis to predict the deformation of a large steel structure, calculation time, modeling, constraints in each assembly stage and critical welding length have to be considered. In case of fillet welding deformation, around 300 mm is sufficient as a critical welding length of the specimen as proposed by the existing researches. However, the critical length in case of butt welding is around 1000 mm, which is far longer than that suggested in the existing researches. For the external constraint, which occurs as the geometry of structure is changed according to the assembly stage, constraint factor is drawn from the elastic FE analysis and test results, and the magnitude of equivalent force according to constraint is decided. The comparison study for the elastic FE analysis result and measurement for the large steel structure based on the above results reveals that the analysis results are in the range of 80–118% against measurement values, both matching each other well. Further, the deformation of fillet welding in the main plate among the total block occupies 66–89%, making welding deformation in the main plate far larger than the welding deformation in the longitudinal

  20. Welding residual stress distributions for dissimilar metal nozzle butt welds in pressurized water reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Soo; Kim, Ju Hee; Bae, Hong Yeol; OH, Chang Young; Kim, Yun Jae [Korea Univ., Seoul (Korea, Republic of); Lee, Kyungsoo [Korea Electric Power Research Institute, Daejeon (Korea, Republic of); Song, Tae Kwang [Korea Institute of Nuclear Safety, Daejeon (Korea, Republic of)

    2012-02-15

    In pressurized water nuclear reactors, dissimilar metal welds are susceptible to primary water stress corrosion cracking. To access this problem, accurate estimation of welding residual stresses is important. This paper provides general welding residual stress profiles in dissimilar metal nozzle butt welds using finite element analysis. By introducing a simplified shape for dissimilar metal nozzle butt welds, changes in the welding residual stress distribution can be seen using a geometry variable. Based on the results, a welding residual stress profile for dissimilar metal nozzle butt welds is proposed that modifies the existing welding residual stress profile for austenitic pipe butt welds.

  1. In-field Welding and Coating Protocols

    Science.gov (United States)

    2009-05-12

    Gas Technology Institute (GTI) and Edison Welding Institute (EWI) created both laboratory and infield girth weld samples to evaluate the effects of weld geometry and hydrogen off-gassing on the performance of protective coatings. Laboratory made plat...

  2. Closed circuit TV system monitors welding operations

    Science.gov (United States)

    Gilman, M.

    1967-01-01

    TV camera system that has a special vidicon tube with a gradient density filter is used in remote monitoring of TIG welding of stainless steel. The welding operations involve complex assembly welding tools and skates in areas of limited accessibility.

  3. Gas Metal Arc Welding Using Novel CaO-Added Mg Alloy Filler Wire

    OpenAIRE

    Minjung Kang; Youngnam Ahn; Cheolhee Kim

    2016-01-01

    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 tr...

  4. Electron Beam Welding: study of process capability and limitations towards development of nuclear components

    Science.gov (United States)

    Vadolia, Gautam R.; Premjit Singh, K.

    2017-04-01

    Electron Beam Welding (EBW) technology is an established and widely adopted technique in nuclear research and development area. Electron beam welding was thought of as a candidate process for ITER Vacuum Vessel Fabrication. Dhruva Reactor at BARC, Mumbai and Niobium superconducting accelerator cavity at BARC has adopted the EB welding technique as a fabrication route. Study of process capability and limitations based on available literature is consolidated in this short review paper.

  5. Factors affecting weld root morphology in laser keyhole welding

    Science.gov (United States)

    Frostevarg, Jan

    2018-02-01

    Welding production efficiency is usually optimised if full penetration can be achieved in a single pass. Techniques such as electron and laser beam welding offer deep high speed keyhole welding, especially since multi-kilowatt lasers became available. However, there are limitations for these techniques when considering weld imperfections such as weld cap undercuts, interior porosity or humps at the root. The thickness of sheets during full penetration welding is practically limited by these root humps. The mechanisms behind root morphology formation are not yet satisfactory understood. In this paper root humping is studied by reviewing previous studies and findings and also by sample examination and process observation by high speed imaging. Different process regimes governing root quality are presented, categorized and explained. Even though this study mainly covers laser beam and laser arc hybrid welding, the presented findings can generally be applied full penetration welding in medium to thick sheets, especially the discussion of surface tension effects. As a final result of this analysis, a map of methods to optimise weld root topology is presented.

  6. 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. c2003 Elsevier Ltd. All rights reserved.

  7. 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.

  8. Experimental Investigation on Laser Impact Welding of Fe-Based Amorphous Alloys to Crystalline Copper.

    Science.gov (United States)

    Wang, Xiao; Luo, Yapeng; Huang, Tao; Liu, Huixia

    2017-05-12

    Recently, amorphous alloys have attracted many researchers' attention for amorphous structures and excellent properties. However, the welding of amorphous alloys to traditional metals in the microscale is not easy to realize in the process with amorphous structures unchanged, which restrains the application in industry. In this paper, a new method of welding Fe-based amorphous alloys (GB1K101) to crystalline copper by laser impact welding (LIW) is investigated. A series of experiments was conducted under different laser energies, during which Fe-based amorphous alloys and crystalline copper were welded successfully by LIW. In addition, the microstructure and mechanical properties of welding joints were observed and measured, respectively. The results showed that the surface wave and springback were observed on the flyer plate after LIW. The welding interface was straight or wavy due to different plastic deformation under different laser energies. The welding interface was directly bonded tightly without visible defects. No visible element diffusion and intermetallic phases were found in the welding interface. The Fe-based amorphous alloys retained amorphous structures after LIW under the laser energy of 835 mJ. The nanoindentation hardness across the welding interface showed an increase on both sides of the welding interface. The results of the lap shearing test showed that the fracture position was on the side of copper coil.

  9. INVESTIGATING SPOT WELD GROWTH ON 304 AUSTENITIC STAINLESS STEEL (2 mm SHEETS

    Directory of Open Access Journals (Sweden)

    NACHIMANI CHARDE

    2013-02-01

    Full Text Available Resistance spot welding (RSW has revolutionized automotive industries since early 1970s for its mechanical assemblies. To date one mechanical assembly out five is welded using spot welding technology in various industries and stainless steel became very popular among common materials. As such this research paper analyses the spot weld growth on 304 austenitic stainless steels with 2mm sample sheets. The growth of a spot weld is primarily determined by its parameters such as current, weld time, electrode tip and force. However other factors such as electrode deformations, corrosions, dissimilar materials and material properties are also affect the weld growth. This paper is intended to analyze only the effects of nuggets growth due to the current and weld time increment with constant force and unchanged electrode tips. A JPC 75kVA spot welder was used to accomplish it and the welded samples were undergone tensile test, hardness test and metallurgical test to characterize the formation of weld nuggets.

  10. Fundamental Laser Welding Process Investigations

    DEFF Research Database (Denmark)

    Bagger, Claus; Olsen, Flemming Ove

    1998-01-01

    In a number of systematic laboratory investigations the fundamental behavior of the laser welding process was analyzed by the use of normal video (30 Hz), high speed video (100 and 400 Hz) and photo diodes. Sensors were positioned to monitor the welding process from both the top side and the rear...... side of the specimen.Special attention has been given to the dynamic nature of the laser welding process, especially during unstable welding conditions. In one series of experiments, the stability of the process has been varied by changing the gap distance in lap welding. In another series...... video pictures (400 Hz), a clear impact on the seam characteristics has been identified when a hump occurs.Finally, a clear correlation between the position of the focus point, the resultant process type and the corresponding signal intensity and signal variation has been found for sheets welded...

  11. Design and Implementation of Software for Resistance Welding Process Simulations

    DEFF Research Database (Denmark)

    Zhang, Wenqi

    2003-01-01

    Based on long time engineering research and dedicated collaborations with industry, a new welding software, SORPAS, has been developed for simulation of resistance projection and spot welding processes applying the powerful finite element method (FEM). In order to make the software directly usable...... by engineers and technicians in industry, all of the important parameters in resistance welding are considered and automatically implemented into the software. With the specially designed graphic user interface for Windows, engineers (even without prior knowledge of FEM) can quickly learn and easily operate...... and utilize the software. All industrial users, including welding engineers from DaimlerChrysler, Volkswangen, PSA Peugeot Citroen, VOLVO, Siemens, ABB and so on, have started using the software just after taking a one-day training course. With the user-friendly facilities for flexible geometric design...

  12. A study on an efficient prediction of welding deformation for T-joint laser welding of sandwich panel PART I : Proposal of a heat source model

    Directory of Open Access Journals (Sweden)

    Jae Woong Kim

    2013-09-01

    Full Text Available The use of I-Core sandwich panel has increased in cruise ship deck structure since it can provide similar bending strength with conventional stiffened plate while keeping lighter weight and lower web height. However, due to its thin plate thickness, i.e. about 4~6 mm at most, it is assembled by high power CO2 laser welding to minimize the welding deformation. This research proposes a volumetric heat source model for T-joint of the I-Core sandwich panel and a method to use shell element model for a thermal elasto-plastic analysis to predict welding deformation. This paper, Part I, focuses on the heat source model. A circular cone type heat source model is newly suggested in heat transfer analysis to realize similar melting zone with that observed in experiment. An additional suggestion is made to consider negative defocus, which is commonly applied in T-joint laser welding since it can provide deeper penetration than zero defocus. The proposed heat source is also verified through 3D thermal elasto-plastic analysis to compare welding deformation with experimental results. A parametric study for different welding speeds, defocus values, and welding powers is performed to investigate the effect on the melting zone and welding deformation. In Part II, focuses on the proposed method to employ shell element model to predict welding deformation in thermal elasto-plastic analysis instead of solid element model.

  13. Pulsed ultrasonic stir welding system

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

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

  14. A Review of Dissimilar Welding Techniques for Magnesium Alloys to Aluminum Alloys

    Directory of Open Access Journals (Sweden)

    Liming Liu

    2014-05-01

    Full Text Available Welding of dissimilar magnesium alloys and aluminum alloys is an important issue because of their increasing applications in industries. In this document, the research and progress of a variety of welding techniques for joining dissimilar Mg alloys and Al alloys are reviewed from different perspectives. Welding of dissimilar Mg and Al is challenging due to the formation of brittle intermetallic compound (IMC such as Mg17Al12 and Mg2Al3. In order to increase the joint strength, three main research approaches were used to eliminate or reduce the Mg-Al intermetallic reaction layer. First, solid state welding techniques which have a low welding temperature were used to reduce the IMCs. Second, IMC variety and distribution were controlled to avoid the degradation of the joining strength in fusion welding. Third, techniques which have relatively controllable reaction time and energy were used to eliminate the IMCs. Some important processing parameters and their effects on weld quality are discussed, and the microstructure and metallurgical reaction are described. Mechanical properties of welds such as hardness, tensile, shear and fatigue strength are discussed. The aim of the report is to review the recent progress in the welding of dissimilar Mg and Al to provide a basis for follow-up research.

  15. A Review of Dissimilar Welding Techniques for Magnesium Alloys to Aluminum Alloys

    Science.gov (United States)

    Liu, Liming; Ren, Daxin; Liu, Fei

    2014-01-01

    Welding of dissimilar magnesium alloys and aluminum alloys is an important issue because of their increasing applications in industries. In this document, the research and progress of a variety of welding techniques for joining dissimilar Mg alloys and Al alloys are reviewed from different perspectives. Welding of dissimilar Mg and Al is challenging due to the formation of brittle intermetallic compound (IMC) such as Mg17Al12 and Mg2Al3. In order to increase the joint strength, three main research approaches were used to eliminate or reduce the Mg-Al intermetallic reaction layer. First, solid state welding techniques which have a low welding temperature were used to reduce the IMCs. Second, IMC variety and distribution were controlled to avoid the degradation of the joining strength in fusion welding. Third, techniques which have relatively controllable reaction time and energy were used to eliminate the IMCs. Some important processing parameters and their effects on weld quality are discussed, and the microstructure and metallurgical reaction are described. Mechanical properties of welds such as hardness, tensile, shear and fatigue strength are discussed. The aim of the report is to review the recent progress in the welding of dissimilar Mg and Al to provide a basis for follow-up research. PMID:28788646

  16. 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...

  17. The effect of post-welding conditions in friction stir welds: From weld simulation to Ductile Failure

    DEFF Research Database (Denmark)

    Hattel, Jesper Henri; Nielsen, Kim Lau; Tutum, Cem Celal

    2012-01-01

    effect of the post-welding conditions when subjecting a friction stir weld to loading transverse to the weld line. The numerical model of the friction stir welded joint, employs a step-wise modeling approach to combine an in-situ weld simulation with a post-welding failure analysis. Using the commercial......The post-welding stress state, strain history and material conditions of friction stir welded joints are often strongly idealized when used in subsequent modeling analyses, typically by neglecting one or more of the features above. But, it is obvious that the conditions after welding do influence...... the weld performance. The objective of this paper is to discuss some of the main conflicts that arise when taking both the post-welding material conditions and stressestrain state into account in a subsequent structural analysis. The discussion is here based on a preliminary numerical study of the possible...

  18. Pulsed ultrasonic stir welding method

    Science.gov (United States)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

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

  19. Reconditioning medical prostheses by welding

    Science.gov (United States)

    Rontescu, C.; Cicic, D. T.; Vasile, I. M.; Bogatu, A. M.; Amza, C. G.

    2017-08-01

    After the technological process of making, some of the medical prostheses may contain imperfections, which can lead to framing the product in the spoilage category. This paper treats the possibility of reconditioning by welding of the prosthesis made of titanium alloys. The paper presents the obtained results after the reconditioning by welding, using the GTAW process, of a intramedullary rod type prosthesis in which was found a crack after the non-destructive examination. The obtained result analysis, after the micrographic examination of the welded joint areas, highlighted that the process of reconditioning by welding can be applied successfully in such situations.

  20. Portable electron beam weld chamber

    Science.gov (United States)

    Lewis, J. R.; Dimino, J. M.

    1972-01-01

    Development and characteristics of portable vacuum chamber for skate type electron beam welding are discussed. Construction and operational details of equipment are presented. Illustrations of equipment are provided.

  1. Performance improvement and development of design and manufacturing technology of KAERI type laser welding tool

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ki Soo; Kim, Heung Cheol; Im Wan Seong [Chungnam National University, Taejon(Korea)

    1998-04-01

    Laser welding technology for repair of steam generator in nuclear power plants is an important research issue for the development of nuclear industry. In order to make credible laser repair welding inside steam generator pipe, it is necessary to device a welding tool which will succeed in accurate laser welding. There have been accomplished drawing including assembly drawing, isometric perspective drawing, dimension of parts, machining accuracy, materials, and machining methods of 3/4 inch laser welding tool to repair steam generator pipe, and also manufacture specification mentioning methods, machining process, test standard, and test methods. The design drawing and manufacture specification will contribute to producing laser welding tool. (author). 6 refs., 5 figs.

  2. Finite Element and Experimental Study of Shunting in Resistance Spot Welding

    DEFF Research Database (Denmark)

    Seyyedian Choobi, M.; Nielsen, C. V.; Bay, N.

    2015-01-01

    conducted to investigate the effect of shunting on nugget size in spot welding of HSLA steel sheets. Different cases with different spacing between weld spots have been examined. The nugget sizes have been measured by metallographic examination and have been compared with 3D finite element simulations......This research is focused on one of the problems frequently encountered in spot welding in industry. In many applications several spot welds are made close to each other. The spots made after the first spot may become smaller in size due to shunt effect. A numerical and experimental study has been....... The results of this study revealed that the shunt effect becomes negligible when the minimum weld spacing is about six times the electrode diameter. The results showed that the weld nugget diameter is more sensitive to shunt effect than the nugget height....

  3. Microstructural evolution during friction stir welding of AlSi1MgMn alloy

    Directory of Open Access Journals (Sweden)

    M. Janjić

    2012-01-01

    Full Text Available This paper provides the research of the infl uence of geometric and kinematic parameters on the microstructure and mechanical properties of welded joint of aluminum alloy AlSi1MgMn (6082-T6 obtained through the Friction Stir Welding (FSW process. The experiment parameters were welding speed, rotation speed, angle of pin slope, pin diameter and shoulder diameter. On the obtained welded workpieces the dynamic testing on the impact toughness, and determination of microstructural zones were carried out.

  4. Underwater Wet Repair Welding of API 5L X65M Pipeline Steel

    Directory of Open Access Journals (Sweden)

    Rogalski Grzegorz

    2017-04-01

    Full Text Available This paper presents results of the research of effect of polymer insulation of pipeline made of API 5L X65M steel as well as underwater wet welding parameters on properties of joints made by covered electrodes. Effect of heat input on structure and hardness of joints during repair of underwater pipeline was analyzed. Welding defects like microcracks, micro-lacks of fusion, slag inclusions, as well as HAZ hardness increase over an assumed acceptance criterion for welded joints in pipes without anticorrosion polymer insulation, were identified. A significant effect of polimer insulation on structure and properties of welded joints, was found.

  5. 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…

  6. Networking and Information Technology Research and Development Program. Supplement to the President’s Budget for Fiscal Year 2011

    Science.gov (United States)

    2010-02-01

    framework and mechanisms for coordination among Federal agencies that support R&D in advanced networking and information technology . The NITRD...Supplement describes the FY 2011 networking and information technology R&D plans and current technical and coordination activities of the 13 Federal member...This Supplement to the President’s Fiscal Year (FY) 2011 Budget provides a technical summary of the budget request for the Networking and Information

  7. Inhibition of the formation of intermetallic compounds in aluminum-steel welded joints by friction stir welding; Inhibicion de la formacion de compuestos intermetalicos en juntas aluminio-acero soldadas por friccion-agitacion

    Energy Technology Data Exchange (ETDEWEB)

    Torres Lopez, E. A.; Ramirez, A. J.

    2015-07-01

    Formation of deleterious phases during welding of aluminum and steel is a challenge of the welding processes, for decades. Friction Stir Welding (FSW) has been used in an attempt to reduce formation of intermetallic compounds trough reducing the heat input. In this research, dissimilar joint of 6063-T5 aluminum alloy and AISI-SAE 1020 steel were welded using this technique. The temperature of welded joints was measured during the process. The interface of the welded joints was characterized using optical microscopy, scanning and transmission electron microscopy. Additionally, composition measurements were carried out by X-EDS and DRX. The experimental results revealed that the maximum temperature on the joint studied is less than 360 degree centigrade. The microstructural characterization in the aluminum-steel interface showed the absence of intermetallic compounds, which is a condition attributed to the use of welding with low thermal input parameters. (Author)

  8. Omega-3 Supplements: An Introduction

    Science.gov (United States)

    ... 3 Supplements in the United States What the Science Says If You Are Considering Omega-3 Supplements NCCIH-Funded Research For More Information Key References ©Thinkstock Introduction Omega-3 fatty acids (omega-3s) are a ...

  9. Preventative lipid-based nutrient supplements (LNS) and young child feeding practices: findings from qualitative research in Haiti.

    Science.gov (United States)

    Lesorogol, Carolyn; Jean-Louis, Sherlie; Green, Jamie; Iannotti, Lora

    2015-12-01

    To prevent undernutrition in an urban slum in Haiti, a lipid-based nutrient supplement (LNS) was introduced through a randomised control trial. Food supplementation for young child nutrition has a long history in Haiti, but there is little empirical information regarding the effects of supplementation on young child feeding practices. One of the concerns raised by supplementation is that it may disrupt other positive feeding practices such as breastfeeding and use of other complementary foods, with negative consequences for child nutrition. We conducted 29 in-depth interviews with mother-baby pairs from the three comparison groups: control, 3-month LNS supplementation and 6-month LNS supplementation. Findings from those in the LNS groups indicated high acceptance and satisfaction with LNS and perceptions that it positively affects child health and development. LNS was integrated into and enhanced ongoing complementary feeding practices. The effects of LNS use on duration and perceived quantity of breastfeeding were variable, but generally, breastfeeding was maintained during and after the intervention. Interviews generated insights into beliefs regarding infant and young child feeding practices such as introduction and use of complementary foods, and breastfeeding duration, exclusivity and cessation. Implications for the use of LNS in public health nutrition programmes are discussed. © 2014 John Wiley & Sons Ltd.

  10. [New welding processes and health effects of welding].

    Science.gov (United States)

    La Vecchia, G Marina; Maestrelli, Piero

    2011-01-01

    This paper describes some of the recent developments in the control technology to enhance capability of Pulse Gas Metal Arc Welding. Friction Stir Welding (FSW) processing has been also considered. FSW is a new solid-state joining technique. Heat generated by friction at the rotating tool softens the material being welded. FSW can be considered a green and energy-efficient technique without deleterious fumes, gas, radiation, and noise. Application of new welding processes is limited and studies on health effects in exposed workers are lacking. Acute and chronic health effects of conventional welding have been described. Metal fume fever and cross-shift decline of lung function are the main acute respiratory effects. Skin and eyes may be affected by heat, electricity and UV radiations. Chronic effects on respiratory system include chronic bronchitis, a benign pneumoconiosis (siderosis), asthma, and a possible increase in the incidence of lung cancer. Pulmonary infections are increased in terms of severity, duration, and frequency among welders.

  11. Laser Welding of Ultrahigh Strength Steels at Subzero Temperatures

    Science.gov (United States)

    Gerhards, Benjamin; Reisgen, Uwe; Olschok, Simon

    Ultrahigh strength steels like press hardened 22MnB5 and S1100QL make good construction materials, however when fusion welded they bring the disadvantage of softening in heat affected zones (HAZ). State of the art research of Laser welding ultrahigh strength steels shows that neither increasing the welding velocity, nor post weld heat treatment have an effect on the strength and hardness drop in the HAZ. The key to improving these material characteristics is to increase heat dissipation out of the workpiece. To do so, the cooling conditions while laser welding press hardened 22MnB5 and S1100QL were dramatically increased. Experiments were carried out at subzero temperatures down to -98°C by using a mixture of liquid and gaseous nitrogen. To further improve heat dissipation, the clamping jaws were entirely made of copper. Hardness measurements and tensile tests were conducted to compare joints welded at room temperature with those welded at -98°C. Whilst an improvement of the hardness values could be achieved for the press hardened 22MnB5 and the S1100, no change in the mechanical behavior regarding tensile tests could be observed. Thus, it can be noticed that there is no possibility to improve the strength levels of martensitic steels throughout varying process parameters (like welding velocity) or utilizing an active cooling, even if subzero temperatures down to -98°C are applied. A further improvement at lower temperatures is unlikely because heat dissipation in the work piece itself is the limiting factor.

  12. Numerical Simulation of Heat and Flow Behaviors in Butt-fusion Welding Process of HDPE Pipes with Curved Fusion Surface

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Jae Hyun; Ahn, Kyung Hyun [Seoul National University, Seoul (Korea, Republic of); Choi, Sunwoong; Oh, Ju Seok [Hannam University, Daejeon (Korea, Republic of)

    2017-08-15

    Butt-fusion welding process is used to join the polymeric pipes. Recently, some researchers suggest the curved surface to enhance a welding quality. We investigated how curved welding surface affects heat and flow behaviors of polymer melt during the process in 2D axisymmetric domain with finite element method, and discussed the effect to the welding quality. In this study, we considered HDPE pipes. In heat soak stage, curved phase interface between the melt and solid is shown along the shape of welding surface. In jointing stage, squeezing flow is generated between curved welding surface and phase interface. The low shear rate in fusion domain reduces the alignment of polymer to the perpendicular direction of pipes, and then this phenomenon is expected to help to enhance the welding quality.

  13. The Investigation of Structure Heterogeneous Joint Welds in Pipelines

    Directory of Open Access Journals (Sweden)

    Lyubimova Lyudmila

    2016-01-01

    Full Text Available Welding joints of dissimilar steels don’t withstand design life. One of the important causes of premature destructions can be the acceleration of steel structural degradation due to cyclic mechanical and thermal gradients. Two zones of tube from steel 12H18N9T, exhibiting the structural instability at early stages of the decomposition of a supersaturated solid austenite solution, were subjected to investigation. Methods of x-ray spectral and structure analysis, micro hardnessmetry were applied for the research. Made the following conclusions, inside and outside tube wall surfaces of hazardous zones in welding joint have different technological and resource characteristics. The microhardness very sensitive to changes of metal structure and can be regarded as integral characteristic of strength and ductility. The welding processes are responsible for the further fibering of tube wall structure, they impact to the characteristics of hot-resistance and long-term strength due to development of ring cracks in the welding joint of pipeline. The monitoring of microhardness and structural phase conversions can be used for control by changes of mechanical properties in result of post welding and reductive heat treatment of welding joints.

  14. Resistance welding of aluminium diecasting; Widerstandspressschweissen von Aluminiumdruckguss

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, K.; Grobelin, K. [Hess Engineering AG, Frauenfeld (Switzerland)

    2001-07-01

    Components consist of die cast with aluminium are used in many machines and vehicles. From economical point of view die casting is a very interesting method to produce moulded components. Aluminium belongs to the most important materials utilized for lightweight construction. It is possible to produce components having high strengths as well as high elongation at rupture by applying new die cast alloys. Since about ten years ago, one is able to weld aluminium die cast successfully. This has become possible because of the improvement of the die cast process after extensive research work. Now components contain only less than the prior common quantities of gas. Resistance suits very well for assembling components consisting of aluminium die cast. High strength is in existence. The porosity has less influence on quality of weld while applying the method of butt welding than applying that one of fusion welding because of occurrences of pressure during butt welding. From the economical view of point, the methods are very suitable for series manufacturing because of the short execution time. Moreover it is an advantage that knowledge gathered for resistance welding of aluminium wrought materials can be mostly applied to aluminium die cast. (orig.)

  15. The effect of pre-diagnostic vitamin D supplementation on cancer survival in women: a cohort study within the UK Clinical Practice Research Datalink.

    Science.gov (United States)

    Jeffreys, Mona; Redaniel, Maria Theresa; Martin, Richard M

    2015-10-12

    There remains uncertainty in whether vitamin D status affects cancer survival. We investigated whether vitamin D (± calcium) supplementation affects cancer survival in women. Participants were women aged ≥55 years identified from the UK Clinical Practice Research Datalink (CPRD) with a first diagnosis of breast, colorectal, lung, ovarian or uterine cancer between 2002 and 2009, and at least 5 years of CPRD data prior to diagnosis. Cox proportional hazards were used to estimate hazard ratios (HR) and 95 % confidence intervals (CI) of the relationship between pre-diagnostic vitamin D supplementation and all-cause mortality. To avoid confounding by indication, the primary analysis compared women with 3+ to 1-2 (but no more) vitamin D prescriptions. Models were adjusted for pre-diagnostic body mass index, smoking, alcohol and deprivation. A sensitivity analysis excluded supplements prescribed in the year prior to diagnosis. Exposure to 3 or more versus 1 to 2 prescriptions of vitamin D was not associated with survival from any of the cancers studied. Any vitamin D prescription, compared to never having been prescribed one, was associated with a better survival from breast cancer (HR 0.78, 95 % CI 0.70 to 0.88). The sensitivity analysis suggested a possible detrimental effect of vitamin D supplementation on lung cancer outcomes (HR for 3 versus 1 or 2 prescriptions 1.22 (95 % CI 0.94 to 1.57); HR for any versus no prescriptions 1.09 (0.98 to 1.22)). We found no evidence that vitamin D supplementation is associated with survival among women with cancer. Previous observational findings of beneficial effects of vitamin D supplementation on cancer survival may be confounded.

  16. Modeling Stress-Strain State in Butt-Welded Joints after TIG Welding

    Directory of Open Access Journals (Sweden)

    V. Atroshenko

    2015-09-01

    Full Text Available In this paper mathematical model was developed for definition of thermal-welding cycle influence on welding deformations distribution in flat samples of austenitic steels after TIG welding and developed recommendations to reduce the welding deformation on o the machinery for welding with a copper backing.

  17. The effect of interlayers on dissimilar friction weld properties

    Science.gov (United States)

    Maldonado-Zepeda, Cuauhtemoc

    The influence of silver interlayers on the metallurgical and mechanical properties of dissimilar aluminium alloy/stainless steel friction welds are investigated. An elastic contact model is proposed that explains the conditions at and close to the contact surface, which produce Al2O3 particle fracture in dissimilar MMC/AISI 304 stainless steel friction welds. Intermixed (IM) and particle dispersed (PD) regions are formed in Ag-containing dissimilar friction welds. These regions form very early in the joining operation and both contain Ag3Al. Therefore, an interlayer (Ag) introduced with the specific aim of preventing FexAly compound formation in MMC/AISI 304 stainless steel friction welds promotes the formation of another intermetallic phase at the bondline. Since IM and PD regions are progressively removed as the friction welding operation proceeds thinner intermetallic layers are produced when long friction welding times are applied. This type of behavior is quite different from that observed in silver-free dissimilar MMC/AISI 304 stainless steel welds. Nanoparticles of silver are formed in dissimilar MMC/Ag/AISI 304 stainless steel welds produced using low friction pressures. Nanoparticle formation in dissimilar friction welds has never been previously observed or investigated. The introduction of silver interlayers decreases heat generation during welding, produces narrower softened zone regions and improved notch tensile strength properties. All research to-date has assumed per se that joint mechanical properties wholly depend on the mechanical properties and width of the intermetallic layer formed at the dissimilar joint interface. However, it is shown in this thesis that the mechanical properties of MMC/AISI 304 stainless steel joints are determined by the combined effects of intermetallic formation at the bondline and softened zone formation in MMC base material immediately adjacent to the joint interface. A methodology for calculating the notch tensile

  18. Welding--Trade or Profession?

    Science.gov (United States)

    Albright, C. E.; Smith, Kenneth

    2006-01-01

    This article discusses a collaborative program between schools with the purpose of training and providing advanced education in welding. Modern manufacturing is turning to automation to increase productivity, but it can be a great challenge to program robots and other computer-controlled welding and joining systems. Computer programming and…

  19. Metal Working and Welding Operations.

    Science.gov (United States)

    Marine Corps Inst., Washington, DC.

    This student guide, one of a series of correspondence training courses designed to improve the job performance of members of the Marine Corps, deals with the skills needed by metal workers and welders. Addressed in the six individual units of the course are the following topics: weldable metals and their alloys, arc welding, gas welding,…

  20. Weld bonding of stainless steel

    DEFF Research Database (Denmark)

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

    2004-01-01

    This paper presents a comprehensive theoretical and experimental investigation of the weld bonding process with the purpose of evaluating its relative performance in case of joining stainless steel parts, against alternative solutions based on structural adhesives or conventional spot-welding. Th...

  1. Extending the value of police crash reports for traffic safety research: collecting supplemental data via surveys of drivers.

    Science.gov (United States)

    Durbin, Dennis R; Myers, Rachel K; Curry, Allison E; Zonfrillo, Mark R; Arbogast, Kristy B

    2015-04-01

    Police crash reports have been used to advance motor vehicle safety research, though their value is limited by their focus on the crash event rather than outcomes of the crash. To develop and evaluate the effect of enhanced recruitment methods, including a monetary incentive, on response rates of drivers identified on police reports in a national MVC surveillance system. The National Automotive Sampling System-General Estimates System (NASS-GES) was used to identify passenger vehicle crashes between 1 July and 30 October 2012 involving drivers ≥16 years old with at least one child occupant ≤17 years old. We collected data from the driver via self-administered hardcopy or interviewer-administered telephone surveys. Within each survey mode, half the drivers were randomly assigned to receive a small monetary incentive. Response rates were calculated overall, and by mode of survey administration and incentive condition. 495 drivers were eligible, and 127 completed the survey, yielding an overall response rate of 25.7% (95% CI 21.8% to 29.5%). The response rate across the two modes was higher for those who received an incentive than for those who did not (35.6% vs 15.7%, p<0.01). The highest response rate (45.9%) was for drivers allocated to the telephone survey who received an incentive. The NASS-GES provides a surveillance system from which cases of interest can be identified and supplemental data collected via surveys of drivers identified on police reports. We adapted procedures commonly used in public health surveillance systems, including monetary incentives and branded recruitment materials, to improve driver response rates. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

  2. EB-welding of the copper canister for the nuclear waste disposal. Final report of the development programme 1994-1997

    Energy Technology Data Exchange (ETDEWEB)

    Aalto, H. [Outokumpu Oy Poricopper, Pori (Finland)

    1998-10-01

    to investigations the creep strength of the copper material is sufficient for repository conditions. The ultrasonic inspection of the weld is very challenging because of large and orientated grain structure of the material. Some additional work is needed to optimise the material grain structure and ultrasonic probes which will be used in full scale canister inspection. The whole research work confirm the applicability of copper as a canister material and gives good basis on manufacture of full size canisters applying EB-welding technique. (author) 12 refs.

  3. Experimental characterization of fatigue strength in butt welded joint considering the geometry and the effect of cooling rate of the weld

    Science.gov (United States)

    Arzola, Nelson; Hernández, Edgar

    2017-05-01

    In this work the experimental characterization of fatigue strength in butt welded joints considering the geometry and the post-weld cooling cycle was performed. ASTM A-36 structural steel was used as the base metal for the shielded metal arc welding process, with welding electrode E6013. Two experimental factors were established: weld bead geometry and the post-weld cooling rate. Two levels for each factor, the welding reinforcement (1 and 3 mm), and the rate of cooling, slow (quiet air) and fast (immersion in water) are evaluated respectively. For the uniaxial fatigue tests, 8 samples were selected for each treatment for a total of 32 specimens. The mechanical and fractomechanical properties of fusion zone, heat affected zone and base metal in relation to the analysis of failure mechanisms were analysed. The fatigue crack growth rates were estimated based on the counting of microstrations. Furthermore, experimental tests, such as uniaxial tension, microindentation hardness, Charpy impact and metallographic analysis, were made to know the influence of the experimental factors in the fatigue strength. On this research, about the 78.13% of the samples obtained a resistance higher than the recommended one by class FAT 100. The results showed that the geometry of the joint is the factor of greatest influence on fatigue strength for butt welded joints; the greater the weld reinforcement the lower the fatigue strength of the joint. Although it is also important to consider other geometric factors of less impact as it is the weld toe radius and the welding chord width.

  4. The effects of welding parameters on ultra-violet light emissions, ozone and CrVI formation in MIG welding.

    Science.gov (United States)

    Dennis, J H; Mortazavi, S B; French, M J; Hewitt, P J; Redding, C R

    1997-01-01

    This paper describes the relationships between ultra-violet emission, ozone generation and CrVI production in MIG welding which were measured as a function of shield gas flow rate, welding voltage, electrode stick-out and shield gas composition using an automatic welding rig that permitted MIG welding under reproducible conditions. The experimental results are interpreted in terms of the physico-chemical processes occurring in the micro- and macro-environments of the arc as part of research into process modification to reduce occupational exposure to ozone and CrVI production rates in MIG welding. We believe the techniques described here, and in particular the use of what we have termed u.v.-ozone measurements, will prove useful in further study of ozone generation and CrVI formation and may be applied in the investigation of engineering control of occupational exposure in MIG and other welding process such as Manual Metal Arc (MMA) and Tungsten Inert Gas (TIG).

  5. 29 CFR 1910.255 - Resistance welding.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Resistance welding. 1910.255 Section 1910.255 Labor... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Welding, Cutting and Brazing § 1910.255 Resistance welding. (a.... Ignitron tubes used in resistance welding equipment shall be equipped with a thermal protection switch. (3...

  6. 46 CFR 154.660 - Pipe welding.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Pipe welding. 154.660 Section 154.660 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS FOR... § 154.660 Pipe welding. (a) Pipe welding must meet Part 57 of this chapter. (b) Longitudinal butt welds...

  7. 49 CFR 179.300-9 - Welding.

    Science.gov (United States)

    2010-10-01

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

  8. METHOD AND SYSTEM FOR LASER WELDING

    DEFF Research Database (Denmark)

    2008-01-01

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

  9. Magnetic Deflection Of Welding Electron Beam

    Science.gov (United States)

    Malinzak, R. Michael; Booth, Gary N.

    1991-01-01

    Electron-beam welds inside small metal parts produced with aid of magnetic deflector. Beam redirected so it strikes workpiece at effective angle. Weld joint positioned to where heavy microfissure concentration removed when subsequent machining required, increasing likelihood of removing any weld defects located in face side of electron-beam weld.

  10. Clamp and Gas Nozzle for TIG Welding

    Science.gov (United States)

    Gue, G. B.; Goller, H. L.

    1982-01-01

    Tool that combines clamp with gas nozzle is aid to tungsten/inert-gas (TIG) welding in hard-to-reach spots. Tool holds work to be welded while directing a stream of argon gas at weld joint, providing an oxygen-free environment for tungsten-arc welding.

  11. An Investigation of the Perception of Professional Development among Mississippi's Secondary Welding Teachers

    Science.gov (United States)

    Ferguson, Douglas Forrest

    2012-01-01

    This research study originated as a result of a paucity of information available regarding how secondary welding teachers in Mississippi perceive the value of professional development they have received within the previous two years. The purpose of this study was to examine the perceptions of Mississippi's secondary welding teachers regarding how…

  12. Spectroscopic closed loop control of penetration depth in laser beam welding process

    NARCIS (Netherlands)

    Beyer, Eckhard; Sibillano, Teresa; Ancona, Antonio; Morris, Timothy; Rizzi, Domenico; Mezzapesa, Francesco; Konuk, A.R.; Aarts, Ronald G.K.M.; Huis in 't Veld, Bert; Lugara, Pietro Mario

    2012-01-01

    In-process monitoring and feedback control are fundamental actions for stable and good quality laser welding process. In particular, penetration depth is one of the most critical features to be monitored. In this research, overlap welding of stainless steel is investigated to stably reproduce a

  13. Mechanistic understanding of hydrogen in steel welds

    Energy Technology Data Exchange (ETDEWEB)

    Suh, D.; Eagar, T.W. [Massachusetts Inst. of Technology, Boston, MA (United States)

    1999-07-01

    Moisture in the flux or the shielding gases, water in the form of hydrated oxides, hydrocarbons, oil, dirt, etc. represent the main sources of hydrogen in welding consumables. Monoatomic and diatomic hydrogen are present in the arc plasma, regardless of the source. The author used the viewpoint of a new absorption model based on the monoatomic and diatomic hydrogen to describe the behaviour of hydrogen in steel welds. The model indicated that the monoatomic hydrogen was absorbed more readily than diatomic hydrogen. The results of the study also indicated that the cooler outer edge represented the main absorption zone of the weld pool, and not the high-temperature central region. This new theory, based on monoatomic hydrogen yielded predictions that are in sharp contrast to those obtained using Sievert's law. Future research is required for the design and development of testing procedures that would allow to differentiate between these theories. Additional research is also required in the field of hydrogen diffusion. 14 refs., 4 figs.

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

    OpenAIRE

    Andreassen, Michael Joachim; Yu, Zhenzhen; Liu, Stephen; Guerrero-Mata, Martha Patricia

    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 fail...

  15. Multi Objective Optimization of Weld Parameters of Boiler Steel Using Fuzzy Based Desirability Function

    Directory of Open Access Journals (Sweden)

    M. Satheesh

    2014-01-01

    Full Text Available The high pressure differential across the wall of pressure vessels is potentially dangerous and has caused many fatal accidents in the history of their development and operation. For this reason the structural integrity of weldments is critical to the performance of pressure vessels. In recent years much research has been conducted to the study of variations in welding parameters and consumables on the mechanical properties of pressure vessel steel weldments to optimize weld integrity and ensure pressure vessels are safe. The quality of weld is a very important working aspect for the manufacturing and construction industries. Because of high quality and reliability, Submerged Arc Welding (SAW is one of the chief metal joining processes employed in industry. This paper addresses the application of desirability function approach combined with fuzzy logic analysis to optimize the multiple quality characteristics (bead reinforcement, bead width, bead penetration and dilution of submerged arc welding process parameters of SA 516 Grade 70 steels(boiler steel. Experiments were conducted using Taguchi’s L27 orthogonal array with varying the weld parameters of welding current, arc voltage, welding speed and electrode stickout. By analyzing the response table and response graph of the fuzzy reasoning grade, optimal parameters were obtained. Solutions from this method can be useful for pressure vessel manufacturers and operators to search an optimal solution of welding condition.

  16. Experimental investigations of tungsten inert gas assisted friction stir welding of pure copper plates

    Science.gov (United States)

    Constantin, M. A.; Boșneag, A.; Nitu, E.; Iordache, M.

    2017-10-01

    Welding copper and its alloys is usually difficult to join by conventional fusion welding processes because of high thermal diffusivity of the copper, alloying elements, necessity of using a shielding gas and a clean surface. To overcome this inconvenience, Friction Stir Welding (FSW), a solid state joining process that relies on frictional heating and plastic deformation, is used as a feasible welding process. In order to achieve an increased welding speed and a reduction in tool wear, this process is assisted by another one (WIG) which generates and adds heat to the process. The aim of this paper is to identify the influence of the additional heat on the process parameters and on the welding joint properties (distribution of the temperature, hardness and roughness). The research includes two experiments for the FSW process and one experiment for tungsten inert gas assisted FSW process. The outcomes of the investigation are compared and analysed for both welding variants. Adding a supplementary heat source, the plates are preheated and are obtain some advantages such as reduced forces used in process and FSW tool wear, faster and better plasticization of the material, increased welding speed and a proper weld quality.

  17. Constitutive model of friction stir weld with consideration of its inhomogeneous mechanical properties

    Science.gov (United States)

    Zhang, Ling; Min, Junying; Wang, Bin; Lin, Jianping; Li, Fangfang; Liu, Jing

    2016-03-01

    In practical engineering, finite element(FE) modeling for weld seam is commonly simplified by neglecting its inhomogeneous mechanical properties. This will cause a significant loss in accuracy of FE forming analysis, in particular, for friction stir welded(FSW) blanks due to the large width and good formability of its weld seam. The inhomogeneous mechanical properties across weld seam need to be well characterized for an accurate FE analysis. Based on a similar AA5182 FSW blank, the metallographic observation and micro-Vickers hardness analysis upon the weld cross-section are performed to identify the interfaces of different sub-zones, i.e., heat affected zone(HAZ), thermal-mechanically affected zone(TMAZ) and weld nugget(WN). Based on the rule of mixture and hardness distribution, a constitutive model is established for each sub-zone to characterize the inhomogeneous mechanical properties across the weld seam. Uniaxial tensile tests of the AA5182 FSW blank are performed with the aid of digital image correlation(DIC) techniques. Experimental local stress-strain curves are obtained for different weld sub-zones. The experimental results show good agreement with those derived from the constitutive models, which demonstrates the feasibility and accuracy of these models. The proposed research gives an accurate characterization of inhomogeneous mechanical properties across the weld seam produced by FSW, which provides solutions for improving the FE simulation accuracy of FSW sheet forming.

  18. Hybrid Laser-Arc Welding of the High-Strength Shipbuilding Steels: Equipment and Technology

    Science.gov (United States)

    Turichin, G.; Kuznetsov, M.; Tsibulskiy, I.; Firsova, A.

    Hybrid laser-arc welding (HLAW) allows getting weld joints with thickness up to 35 mm for one pass, provide good quality formation of joints, minimal thermal deformations, the productivity in 10 times more in comparison with arc welding. In addition, replacement arc welding to the HLAW allows economizing filler materials, shielding gas and consumable electricity more than 4 times. Therefore, HLAW is actually technology for basic engineering branches and especially for shipbuilding. The Institute of Laser and Welding Technologies (ILWT) developed laser and hybrid laser-arc welding technologies for different type of steels and alloys including high-strength shipbuilding steels. Also ILWT produced portal and robotic systems for HLAW process realization. Portal system for hybrid laser-arc welding of panels with dimensions 6x6 m using at the manufacturing of flat curvilinear sections in the shipbuilding is depicted in the article. Results of experimental researches of the hybrid laser-arc welding parameters influence on the formation and mechanical properties of weld joint are described at the publication also. Experimental part was made with using of the portal system.

  19. Automatic welding of stainless steel tubing

    Science.gov (United States)

    Clautice, W. E.

    1978-01-01

    The use of automatic welding for making girth welds in stainless steel tubing was investigated as well as the reduction in fabrication costs resulting from the elimination of radiographic inspection. Test methodology, materials, and techniques are discussed, and data sheets for individual tests are included. Process variables studied include welding amperes, revolutions per minute, and shielding gas flow. Strip chart recordings, as a definitive method of insuring weld quality, are studied. Test results, determined by both radiographic and visual inspection, are presented and indicate that once optimum welding procedures for specific sizes of tubing are established, and the welding machine operations are certified, then the automatic tube welding process produces good quality welds repeatedly, with a high degree of reliability. Revised specifications for welding tubing using the automatic process and weld visual inspection requirements at the Kennedy Space Center are enumerated.

  20. Automatic welding systems for large ship hulls

    Science.gov (United States)

    Arregi, B.; Granados, S.; Hascoet, JY.; Hamilton, K.; Alonso, M.; Ares, E.

    2012-04-01

    Welding processes represents about 40% of the total production time in shipbuilding. Although most of the indoor welding work is automated, outdoor operations still require the involvement of numerous operators. To automate hull welding operations is a priority in large shipyards. The objective of the present work is to develop a comprehensive welding system capable of working with several welding layers in an automated way. There are several difficulties for the seam tracking automation of the welding process. The proposed solution is the development of a welding machine capable of moving autonomously along the welding seam, controlling both the position of the torch and the welding parameters to adjust the thickness of the weld bead to the actual gap between the hull plates.

  1. Microstructure and Mechanical Properties of an Ultrasonic Spot Welded Aluminum Alloy: The Effect of Welding Energy

    National Research Council Canada - National Science Library

    He Peng; Daolun Chen; Xianquan Jiang

    2017-01-01

    The aim of this study is to evaluate the microstructures, tensile lap shear strength, and fatigue resistance of 6022-T43 aluminum alloy joints welded via a solid-state welding technique-ultrasonic spot welding (USW...

  2. Versatile Friction Stir Welding/Friction Plug Welding System

    Science.gov (United States)

    Carter, Robert

    2006-01-01

    A proposed system of tooling, machinery, and control equipment would be capable of performing any of several friction stir welding (FSW) and friction plug welding (FPW) operations. These operations would include the following: Basic FSW; FSW with automated manipulation of the length of the pin tool in real time [the so-called auto-adjustable pin-tool (APT) capability]; Self-reacting FSW (SRFSW); SR-FSW with APT capability and/or real-time adjustment of the distance between the front and back shoulders; and Friction plug welding (FPW) [more specifically, friction push plug welding] or friction pull plug welding (FPPW) to close out the keyhole of, or to repair, an FSW or SR-FSW weld. Prior FSW and FPW systems have been capable of performing one or two of these operations, but none has thus far been capable of performing all of them. The proposed system would include a common tool that would have APT capability for both basic FSW and SR-FSW. Such a tool was described in Tool for Two Types of Friction Stir Welding (MFS- 31647-1), NASA Tech Briefs, Vol. 30, No. 10 (October 2006), page 70. Going beyond what was reported in the cited previous article, the common tool could be used in conjunction with a plug welding head to perform FPW or FPPW. Alternatively, the plug welding head could be integrated, along with the common tool, into a FSW head that would be capable of all of the aforementioned FSW and FPW operations. Any FSW or FPW operation could be performed under any combination of position and/or force control.

  3. Real time computer controlled weld skate

    Science.gov (United States)

    Wall, W. A., Jr.

    1977-01-01

    A real time, adaptive control, automatic welding system was developed. This system utilizes the general case geometrical relationships between a weldment and a weld skate to precisely maintain constant weld speed and torch angle along a contoured workplace. The system is compatible with the gas tungsten arc weld process or can be adapted to other weld processes. Heli-arc cutting and machine tool routing operations are possible applications.

  4. Corrosion Properties of Laser Welded Stainless Steel

    DEFF Research Database (Denmark)

    Weldingh, Jakob; Olsen, Flemmming Ove

    1997-01-01

    In this paper the corrosion properties of laser welded AISI 316L stainless steel are examined. A number of different welds has been performed to test the influence of the weld parameters of the resulting corrosion properties. It has been chosen to use the potential independent critical pitting...... temperature (CPT) test as corrosion test. The following welding parameters are varied: Welding speed, lsser power, focus point position and laser operation mode (CW or pulsed)....

  5. Effects of nitrogen in shielding gas on microstructure evolution and localized corrosion behavior of duplex stainless steel welding joint

    Science.gov (United States)

    Zhang, Zhiqiang; Jing, Hongyang; Xu, Lianyong; Han, Yongdian; Zhao, Lei; Zhou, Chao

    2017-05-01

    The effects of nitrogen addition in shielding gas on microstructure evolution and localized corrosion behavior of duplex stainless steel (DSS) welds were studied. N2-supplemented shielding gas facilitated the primary austenite formation, suppressed the Cr2N precipitation in weld root, and increased the microhardnesses of weld metal. Furthermore, N2-supplemented shielding gas increased pitting resistance equivalent number (PREN) of austenite, but which decreased slightly PREN of ferrite. The modified double loop electrochemical potentiokinetic reactivation in 2 M H2SO4 + 1 M HCl was an effective method to study the localized corrosion of the different zones in the DSS welds. The adding 2% N2 to pure Ar shielding gas improved the localized corrosion resistance in the DSS welds, which was due to compensation for nitrogen loss and promoting nitrogen further solution in the austenite phases, suppression of the Cr2N precipitation in the weld root, and increase of primary austenite content with higher PREN than the ferrite and secondary austenite. Secondary austenite are prone to selective corrosion because of lower PREN compared with ferrite and primary austenite. Cr2N precipitation in the pure Ar shielding weld root and heat affected zone caused the pitting corrosion within the ferrite and the intergranular corrosion at the ferrite boundary. In addition, sigma and M23C6 precipitation resulted in the intergranular corrosion at the ferrite boundary.

  6. Control of Welding Processes.

    Science.gov (United States)

    1987-01-01

    Structures, Office of Deputy Under Secretary of Defense for R&E (ET), Department of Defense, Washington, D.C. CHARLES ZANIS, Assistant Director for Platform... CHARLES NULL, Head, Metals Branch, Naval Sea Systems Command, Washington, D.C. ROBERT A. WEBER, Welding Engineering and Metallurgy, U.S. Army Corps of...Needs. Pp. 487-90. in Papers Presented at the August 3-8, 1Q80, AIME Syi,.posium. Essers, W . ., and R. Walter. Heat transfer and penet ration

  7. Pulmonary fibrosis and exposure to steel welding fume.

    Science.gov (United States)

    Cosgrove, M P

    2015-12-01

    Arc welders who have been exposed to high concentrations of steel welding fume for prolonged periods of time may develop pulmonary fibrosis but the nature of the fibrotic changes has been debated over the last 80 years without any clear international consensus. To characterize the nature of the pulmonary fibrosis that develops in response to steel welding fume exposure and to provide a working hypothesis that would explain the findings of the existing research, to provide a platform for future research and to inform future occupational and clinical management of welders with pulmonary effects from welding fume. Review of the world literature on pulmonary fibrosis and welding of steel in all languages using PubMed, with further secondary search of references in the articles found in the primary search. Google and Reference Manager were used as further confirmatory search tools. Only case series and case reports were found but these provided consistent evidence that the consequence of exposure to steel welding fume at high levels for a prolonged period of time is a type of pulmonary fibrosis similar to, and possibly the same as, respiratory bronchiolitis which eventually develops into desquamative interstitial pneumonia with ongoing exposure. Steel welding fume may cause an occupational respiratory bronchiolitis which may develop into de squamative interstitial pneumonia with ongoing exposure. This concept may explain the difficulties in interpreting the wider literature on welding fume and lung function at lower exposures and may also explain the increased risk of lung cancer in welders. © The Author 2015. Published by Oxford University Press on behalf of the Society of Occupational Medicine. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. The effect of friction welding self-regulation process on weld structure and hardness

    Directory of Open Access Journals (Sweden)

    W. Ptak

    2010-07-01

    Full Text Available The self-regulation phenomenon that occurs during friction welding process was characterised, and the effect of the self-regulation of theenergy-related parameters on structure and hardness distribution in SW7Mo steel – 55 steel welded joint was determined experimentally.The structure and hardness of the weld zone were examined, the energy required for the stable run of a friction welding process wascalculated, and a relationship between the welding energy and weld hardness was derived.

  9. Calcium supplements

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/007477.htm Calcium supplements To use the sharing features on this page, please enable JavaScript. WHO SHOULD TAKE CALCIUM SUPPLEMENTS? Calcium is an important mineral for the ...

  10. 10,170 flawless welds

    CERN Multimedia

    Antonella Del Rosso

    2014-01-01

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

  11. Laser welding of fused quartz

    Science.gov (United States)

    Piltch, Martin S.; Carpenter, Robert W.; Archer, III, McIlwaine

    2003-06-10

    Refractory materials, such as fused quartz plates and rods are welded using a heat source, such as a high power continuous wave carbon dioxide laser. The radiation is optimized through a process of varying the power, the focus, and the feed rates of the laser such that full penetration welds may be accomplished. The process of optimization varies the characteristic wavelengths of the laser until the radiation is almost completely absorbed by the refractory material, thereby leading to a very rapid heating of the material to the melting point. This optimization naturally occurs when a carbon dioxide laser is used to weld quartz. As such this method of quartz welding creates a minimum sized heat-affected zone. Furthermore, the welding apparatus and process requires a ventilation system to carry away the silicon oxides that are produced during the welding process to avoid the deposition of the silicon oxides on the surface of the quartz plates or the contamination of the welds with the silicon oxides.

  12. Effect of Weld Properties on the Crush Strength of the PWR Spacer Grid

    Directory of Open Access Journals (Sweden)

    Kee-nam Song

    2012-01-01

    Full Text Available Mechanical properties in a weld zone are different from those in the base material because of different microstructures. A spacer grid in PWR fuel is a structural component with an interconnected and welded array of slotted grid straps. Previous research on the strength analyses of the spacer grid was performed using base material properties owing to a lack of mechanical properties in the weld zone. In this study, based on the mechanical properties in the weld zone of the spacer grid recently obtained by an instrumented indentation technique, the strength analyses considering the mechanical properties in the weld zone were performed, and the analysis results were compared with the previous research.

  13. Susceptibility testing for welding of AlMg alloys intended for extrusion

    Directory of Open Access Journals (Sweden)

    J. Borowski

    2016-07-01

    Full Text Available The objective of research was to determine the weldability, using Tungsten Inert Gas (TIG of extruded sections made of hard-deformable 5xxx series aluminum alloys with differing magnesium content, i.e. AlMg3, AlMg4,5, AlMg5, AlMg7. Welded joints were obtained as a result of a welding process consisting of several steps. Only welds characterized by very good appearance and quality were selected for tests. As a result of conducted research, TIG welding parameters were determined for sections with a thickness of 8 mm. It was observed that alloys of differing Mg content are characterized by high weldability and do not exhibit a significant reduction of the yield point. Moreover, joints exhibit uniform hardness distribution in the welded joint and heat-affected zone. Tensile strength is reduced.

  14. The technology and welding joint properties of hybrid laser-tig welding on thick plate

    Science.gov (United States)

    Shenghai, Zhang; Yifu, Shen; Huijuan, Qiu

    2013-06-01

    The technologies of autogenous laser welding and hybrid laser-TIG welding are used on thick plate of high strength lower alloy structural steel 10CrNiMnMoV in this article. The unique advantages of hybrid laser-TIG welding is summarized by comparing and analyzing the process parameters and welding joints of autogenous laser welding laser welding and hybrid laser-TIG welding. With the optimal process parameters of hybrid welding, the good welding joint without visible flaws can be obtained and its mechanical properties are tested according to industry standards. The results show that the hybrid welding technology has certain advantages and possibility in welding thick plates. It can reduce the demands of laser power, and it is significant for lowering the aspect ratio of weld during hybrid welding, so the gas in the molten pool can rise and escape easily while welding thick plates. Therefore, the pores forming tendency decreases. At the same time, hybrid welding enhances welding speed, and optimizes the energy input. The transition and grain size of the microstructure of hybrid welding joint is better and its hardness is higher than base material. Furthermore, its tensile strength and impact toughness is as good as base material. Consequently, the hybrid welding joint can meet the industry needs completely.

  15. The Welding Institute has developed the strategy of the LHC magnets welding; L' institut de soudure a developpe la strategie de soudage des aimants du LHC

    Energy Technology Data Exchange (ETDEWEB)

    Champigny, F

    2008-11-15

    The Welding Institute has participated to the realization of the Large Hadron Collider (LHC) in the framework of two expert missions, the first one in research and development and the other one in inspection. (O.M.)

  16. Review of laser hybrid welding

    DEFF Research Database (Denmark)

    Bagger, Claus

    2004-01-01

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

  17. Convection in arc weld pools

    Energy Technology Data Exchange (ETDEWEB)

    Oreper, G.M.; Eagar, T.W.; Szekely, J.

    1982-11-01

    A mathematical model was developed to account for convection and temperature distributions in stationary arc weld pools driven by buoyancy, electromagnetic and surface tension forces. It is shown that the electromagnetic and surface tension forces dominate the flow behavior. In some cases, these forces produce double circulation loops, which are indirectly confirmed by experimental measurements of segregation in the weld pool. It is also shown that the surface tension driven flows are very effective in dissipating the incident energy flux on the pool surface which, in turn, reduces the vaporization from the weld pool.

  18. Plasticity Theory of Fillet Welds

    DEFF Research Database (Denmark)

    Hansen, Thomas

    2005-01-01

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

  19. Specification and qualification of welding procedures for metallic materials : welding procedure test : part 1 : arc and gas welding of steels and arc welding of nickel and nickel alloys : technical corrigendum 1

    CERN Document Server

    International Organization for Standardization. Geneva

    2005-01-01

    Specification and qualification of welding procedures for metallic materials : welding procedure test : part 1 : arc and gas welding of steels and arc welding of nickel and nickel alloys : technical corrigendum 1

  20. Automated Variable-Polarity Plasma-Arc Welding

    Science.gov (United States)

    Numes, A. C., Jr.; Bayless, E. O., Jr.; Jones, S. C., III; Munafo, P.; Munafo, A.; Biddle, A.; Wilson, W.

    1984-01-01

    Variable-polarity plasma-arc methods produces better welds at lower cost than gas-shielded tungsten-arc welding in assemblies. Weld porosity very low and costs of joint preparation, depeaking, inspection, and weld repair minimized.

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

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Z. (Nuclear Engineering Division)

    2012-04-03

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

  2. Spectral diagnostics of a vapor-plasma plume produced during welding titanium with a high-power ytterbium fiber laser

    Science.gov (United States)

    Uspenskiy, S. A.; Petrovskiy, V. N.; Bykovskiy, D. P.; Mironov, V. D.; Prokopova, N. M.; Tret'yakov, E. V.

    2015-03-01

    This work is devoted to the research of welding plume during high power ytterbium fiber laser welding of a titanium alloy in the Ar shielding gas environment. High speed video observation of a vapor-plasma plume for visualization of processes occurring at laser welding was carried out. The coefficient of the inverse Bremsstrahlung absorption of laser radiation is calculated for a plasma welding plume by results of spectrometer researches. The conclusion deals with the impact of plasma on a high-power fiber laser radiation.

  3. Filler wire for aluminum alloys and method of welding

    Science.gov (United States)

    Bjorkman, Jr., Gerald W. O. (Inventor); Cho, Alex (Inventor); Russell, Carolyn K. (Inventor)

    2003-01-01

    A weld filler wire chemistry has been developed for fusion welding 2195 aluminum-lithium. The weld filler wire chemistry is an aluminum-copper based alloy containing high additions of titanium and zirconium. The additions of titanium and zirconium reduce the crack susceptibility of aluminum alloy welds while producing good weld mechanical properties. The addition of silver further improves the weld properties of the weld filler wire. The reduced weld crack susceptibility enhances the repair weldability, including when planishing is required.

  4. Predicting welding residual stresses in a dissimilar metal girth welded pipe using 3D finite element model with a simplified heat source

    Energy Technology Data Exchange (ETDEWEB)

    Deng, Dean, E-mail: deandeng@cqu.edu.c [College of Materials Science and Engineering, Chongqing University, Shazheng Street 174, Shapingba, Chongqing 400044 (China); Kiyoshima, Shoichi [Research Center of Computational Mechanics, Inc., Togoshi NI-Bldg., 1-7-1 Togoshi, Shinagawa-ku, Tokyo 142-0041 (Japan); Ogawa, Kazuo [Japan Nuclear Energy Safety Organization, TOKYU REIT Toranomon Bldg, 3-17-1, Toranomon, Minato-ku, Tokyo 105-0001 (Japan); Yanagida, Nobuyoshi [Hitachi Ltd. 1-1, Saiwa-cho 3-chome, Hitachi-shi, Ibaraki-ken 317-8511 (Japan); Saito, Koichi [Hitachi-GE Nuclear Energy, Ltd. 2-2, Omika-cho, 5-chome, Hitachi-shi, Ibaraki-ken 319-1221 (Japan)

    2011-01-15

    Research highlights: Welding residual stresses have asymmetrical distributions in the dissimilar metal pipe. Variable length heat source model can largely save computing time. Besides welding, other thermal processes also affect residual stresses. - Abstract: Dissimilar metal welds are commonly used in nuclear power plants to connect low alloy steel components and austenitic stainless steel piping systems. The integrity assessment and life estimation for such welded structures require consideration of residual stresses induced by manufacturing processes. Because the fabrication process of dissimilar metal weld joints is considerably complex, it is very difficult to accurately predict residual stresses. In this study, both numerical simulation technology and experimental method were used to investigate welding residual stress distribution in a dissimilar metal pipe joint with a medium diameter, which were performed by a multi-pass welding process. Firstly, an experimental mock-up was fabricated to measure the residual stress distributions on the inside and the outside surfaces. Then, a time-effective 3-D finite element model was developed to simulate welding residual stresses through using a simplified moving heat source. The simplified heat source method could complete the thermo-mechanical analysis in an acceptable time, and the simulation results generally matched the measured data near the weld zone. Through comparing the simulation results and the experimental measurements, we can infer that besides the multi-pass welding process other key manufacturing processes such as cladding, buttering and heat treatment should also be taken into account to accurately predict residual stresses in the whole range of the dissimilar metal pipe.

  5. MFDC - technological improvement in resistance welding controls

    Energy Technology Data Exchange (ETDEWEB)

    Somani, A.K.; Naga Bhaskar, V.; Chandramouli, J.; Rameshwara Rao, A. [Nuclear Fuel Complex, Dept. of Atomic Energy, Hyderabad (India)

    2008-07-01

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

  6. Gas Shielding Technology for Welding and Brazing

    Science.gov (United States)

    Nunes, Arthur J.; Gradl, Paul R.

    2012-01-01

    Welding is a common method that allows two metallic materials to be joined together with high structural integrity. When joints need to be leak-tight, light-weight, or free of contaminant-trapping seams or surface asperities, welding tends to be specified. There are many welding techniques, each with its own advantages and disadvantages. Some of these techniques include Forge Welding, Gas Tungsten Arc Welding, Friction Stir Welding, and Laser Beam Welding to name a few. Whichever technique is used, the objective is a structural joint that meets the requirements of a particular component or assembly. A key practice in producing quality welds is the use of shielding gas. This article discusses various weld techniques, quality of the welds, and importance of shielding gas in each of those techniques. Metallic bonds, or joints, are produced when metals are put into intimate contact. In the solid-state "blacksmith welding" process, now called Forge Welding (FOW), the site to be joined is pounded into intimate contact. The surfaces to be joined usually need to be heated to make it easier to deform the metal. The surfaces are sprinkled with a flux to melt surface oxides and given a concave shape so that surface contamination can be squeezed out of the joint as the surfaces are pounded together; otherwise the surface contamination would be trapped in the joint and would weaken the weld. In solid-state welding processes surface oxides or other contamination are typically squeezed out of the joint in "flash."

  7. Welding and Production Metallurgy Facility

    Data.gov (United States)

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

  8. Thermomechanical Modelling of Resistance Welding

    DEFF Research Database (Denmark)

    Bay, Niels; Zhang, Wenqi

    2007-01-01

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

  9. Laser Welding of Ship Steel

    National Research Council Canada - National Science Library

    Brayton, W. C; Banas, C. M; Peters, G. T

    1979-01-01

    ... joint cleanliness and fitup conditions. In the current program, welds were formed between surfaces with nonperfect fitup, between plasma-cut surfaces, between surfaces deliberately mismatched to provide a varging joint gap and under out...

  10. Supplemental instruction in chemistry

    Science.gov (United States)

    Lundeberg, Mary A.

    This study was designed to measure some effects of supplemental instruction in chemistry. Supplemental instruction is a peer-led cooperative learning program that encourages students to develop conceptual understanding by articulating both understandings and misconceptions in a think-aloud fashion. Supplemental instruction was offered three hours weekly outside of class and lab time for students in four classes of General Organic and Biological Chemistry. Over a two-year period 108 students volunteered to participate in this program; 45 students did not participate. As measured by final grades in chemistry and responses to a questionnaire, supplemental instruction was effective in increasing students' achievement in chemistry. Further research is needed to determine the in-depth effects of supplemental instruction on students' learning, problem solving, and self-esteem.

  11. Resveratrol food supplements

    DEFF Research Database (Denmark)

    Aschemann-Witzel, Jessica; Grunert, Klaus G

    2015-01-01

    Background: Consumers increasingly choose food supplements in addition to their diet. Research on supplement users finds they are likely to be female, older and well-educated; Furthermore, supplement users are often characterised as being especially health-oriented, an observation which is termed...... the ‘inverse supplement hypothesis’. However, results are dependent on the substance in question. Little is known so far about botanicals in general, and more specifically, little is known about resveratrol. The psychographic variables of food supplement users are yet relatively underexplored. By comparing US...... and Danish respondents, we aimed to identify whether sociodemographic variables, health status, health beliefs and behaviour and interest in food aspects specifically relevant to resveratrol (e.g., naturalness, indulgence, and Mediterranean food) explain favourable attitudes and adoption intentions toward...

  12. An investigation on capability of hybrid Nd:YAG laser-TIG welding technology for AA2198 Al-Li alloy

    Science.gov (United States)

    Faraji, Amir Hosein; Moradi, Mahmoud; Goodarzi, Massoud; Colucci, Pietro; Maletta, Carmine

    2017-09-01

    This paper surveys the capability of the hybrid laser-arc welding in comparison with lone laser welding for AA2198 aluminum alloy experimentally. In the present research, a continuous Nd:YAG laser with a maximum power of 2000 W and a 350 A electric arc were used as two combined welding heat sources. In addition to the lone laser welding experiments, two strategies were examined for hybrid welding; the first one was low laser power (100 W) accompanied by high arc energy, and the second one was high laser power (2000 W) with low arc energy. Welding speed and arc current varied in the experiments. The influence of heat input on weld pool geometry was surveyed. The macrosection, microhardness profile and microstructure of the welded joints were studied and compared. The results indicated that in lone laser welding, conduction mode occurred and keyhole was not formed even in low welding speeds and thus the penetration depth was so low. It was also found that the second approach (high laser power accompanied with low arc energy) is superior to the first one (low laser power accompanied with high arc energy) in hybrid laser-arc welding of Al2198, since lower heat input was needed for full penetration weld and as a result a smaller HAZ was created.

  13. New Method for Mitigating the Tensile Residual Stresses induced on the Inside Wall of Butt Welded Pipes

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Jin; Kim, Kang Soo; Kim, Ki Baik; Kim, Kwang Mo; Lee, Bong Sang [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2009-10-15

    Because dissimilar metal welding between ferritic steel and austenitic stainless steel needs not post weld heat treatment (PWHT), the effect of residual stresses induce during the welding should be investigated to assess the reliability of the weld process. It is known that the A82/182 weld metals, which are used for filler metals of the butt welding between the ferritic steel pipe and the stainless steel pipe, are susceptible to PWSCC (Primary Water Stress Corrosion Cracking) in PWR plant. The tensile residual stresses on the inside wall of the pipe, which are induced during the production welding, tend to be the dominant driving force for the PWSCC initiation and crack growth. In order to prevent the PWSCC the tensile residual stresses should be mitigated or removed. Two methods, weld overlay and mechanical stress improvement process (MSIP) have been considered proper tools to reduce the tensile residual stresses and to mitigate the PWSCC susceptibility of the dissimilar metal welded nozzles and pipes. In this research, new method for mitigating the tensile residual stresses induced on the inside wall of pipe during the production welding between the ferritic steel pipe and the stainless steel pipe was suggested. This new method may be able to apply to the SA508 /A182/SS316 nozzles of the pressure vessels in PWR to prevent PWSCC susceptibility as another substitute method.

  14. Narrow gap HST welding process and its application to candidate pipe material for 700 C USC boiler component

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Gang; Sato, Takashi; Fukuda, Yuji [Babcock-Hitachi K.K., Hiroshima (Japan). Kure Research Lab.; Mitsuhata, Koichi [Babcock-Hitachi K.K., Hiroshima (Japan). Kure Div.

    2008-07-01

    Increasing steam temperature and pressure conditions of 700 C USC (Ultra Super Critical) power plants under consideration require the adoption of Ni-based alloys. One of the most crucial issues for the application of 700 C USC power plants is the establishment of welding technology for the thick-walled components. This paper reports the research results on the practicability of candidate material for the thickwalled components. The weld test was conducted on Ni-based Alloy617 (52Ni-22Cr- 13Co-9Mo-Ti-Al) by using the narrow gap HST (Hot wire Switching TIG) welding process developed by Babcock-Hitachi K.K with the matching filler wire of Alloy617. The weldability and strength properties of weld joint were examined. The sound weld joint was achieved. The advantages of narrow gap HST welding process for the thick-walled components of Ni-based alloy were discussed from the viewpoints of weld metal chemical composition and creep rupture strength. Due to the good shielding effect, the melting loss of alloy elements in the weld consumable during the narrow gap HST welding procedure was suppressed successfully. The narrow gap HST weld joint showed comparable strength with the parent metal. (orig.)

  15. Experiments and simulation for 6061-T6 aluminum alloy resistance spot welded lap joints

    Science.gov (United States)

    Florea, Radu Stefanel

    This comprehensive study is the first to quantify the fatigue performance, failure loads, and microstructure of resistance spot welding (RSW) in 6061-T6 aluminum (Al) alloy according to welding parameters and process sensitivity. The extensive experimental, theoretical and simulated analyses will provide a framework to optimize the welding of lightweight structures for more fuel-efficient automotive and military applications. The research was executed in four primary components. The first section involved using electron back scatter diffraction (EBSD) scanning, tensile testing, laser beam profilometry (LBP) measurements, and optical microscopy(OM) images to experimentally investigate failure loads and deformation of the Al-alloy resistance spot welded joints. Three welding conditions, as well as nugget and microstructure characteristics, were quantified according to predefined process parameters. Quasi-static tensile tests were used to characterize the failure loads in specimens based upon these same process parameters. Profilometer results showed that increasing the applied welding current deepened the weld imprints. The EBSD scans revealed the strong dependency between the grain sizes and orientation function on the process parameters. For the second section, the fatigue behavior of the RSW'ed joints was experimentally investigated. The process optimization included consideration of the forces, currents, and times for both the main weld and post-heating. Load control cyclic tests were conducted on single weld lap-shear joint coupons to characterize the fatigue behavior in spot welded specimens. Results demonstrate that welding parameters do indeed significantly affect the microstructure and fatigue performance for these welds. The third section comprised residual strains of resistance spot welded joints measured in three different directions, denoted as in-plane longitudinal, in-plane transversal, and normal, and captured on the fusion zone, heat affected zone

  16. Automatic Control Of Length Of Welding Arc

    Science.gov (United States)

    Iceland, William F.

    1991-01-01

    Nonlinear relationships among current, voltage, and length stored in electronic memory. Conceptual microprocessor-based control subsystem maintains constant length of welding arc in gas/tungsten arc-welding system, even when welding current varied. Uses feedback of current and voltage from welding arc. Directs motor to set position of torch according to previously measured relationships among current, voltage, and length of arc. Signal paths marked "calibration" or "welding" used during those processes only. Other signal paths used during both processes. Control subsystem added to existing manual or automatic welding system equipped with automatic voltage control.

  17. Ship construction and welding

    CERN Document Server

    Mandal, Nisith R

    2017-01-01

    This book addresses various aspects of ship construction, from ship types and construction materials, to welding technologies and accuracy control. The contents of the book are logically organized and divided into twenty-one chapters. The book covers structural arrangement with longitudinal and transverse framing systems based on the service load, and explains basic structural elements like hatch side girders, hatch end beams, stringers, etc. along with structural subassemblies like floors, bulkheads, inner bottom, decks and shells. It presents in detail double bottom construction, wing tanks & duct keels, fore & aft end structures, etc., together with necessary illustrations. The midship sections of various ship types are introduced, together with structural continuity and alignment in ship structures. With regard to construction materials, the book discusses steel, aluminum alloys and fiber reinforced composites. Various methods of steel material preparation are discussed, and plate cutting and form...

  18. Welding of Prosthetic Alloys

    Directory of Open Access Journals (Sweden)

    Wojciechowska M.

    2015-04-01

    Full Text Available This paper presents the techniques of joining metal denture elements, used in prosthetic dentistry: the traditional soldering technique with a gas burner and a new technique of welding with a laser beam; the aim of the study was to make a comparative assessment of the quality of the joints in view of the possibility of applying them in prosthetic structures. Fractographic examinations were conducted along with tensile strength and impact strength tests, and the quality of the joints was assessed compared to the solid metal. The experiments have shown that the metal elements used to make dentures, joined by the technique which employs a laser beam, have better strength properties than those achieved with a gas burner.

  19. Ultrasound influence on materials structure in parts reconditioned by welding with ultrasonic field

    Directory of Open Access Journals (Sweden)

    D. Dobrotă

    2013-01-01

    Full Text Available Research presented in the paper refers to the structural analysis of materials that are thermally influenced for loading by welding of pieces in the classical variant of manual coated electric arc welding and the version that in which the welding bath is activated by ultrasounds. The structural analysis made refer to: the size of the grains of the structure obtained under certain loading conditions through welding, grain size variation on the submission of a single layer in the ultrasonic field, the mode of solidification and fragmentation of grains when loaded in welding in a ultrasonic field, acceleration of the diffusion process for ultrasonic activation, the appearance of hard carbides between grains.

  20. Yb-fibre Laser Welding of 6 mm Duplex Stainless Steel 2205

    Science.gov (United States)

    Bolut, M.; Kong, C. Y.; Blackburn, J.; Cashell, K. A.; Hobson, P. R.

    Duplex stainless steel (DSS) is one of the materials of choice for structural and nuclear applications, having high strength and good corrosion resistance when compared with other grades of stainless steel. The welding process used to join these materials is critical as transformation of the microstructure during welding directly affects the material properties. High power laser welding has recently seen an increase in research interest as it offers both speed and flexibility. This paper presents an investigation into the important parameters affecting laser welding of DSS grade 2205, with particular focus given to the critical issue of phase transformation during welding. Bead-on-plate melt-run trials without filler material were performed on 6mm thick plates using a 5 kW Yb-fibre laser. The laser beam was characterized and a Design of Experiment approach was used to quantify the impact of the process parameters. Optical metallographic methods were used to examine the resulting microstructures.

  1. A review of literature from the First International Conference on Friction Stir Welding

    Energy Technology Data Exchange (ETDEWEB)

    Bowyer, W.H. [Meadow End Farm, Farnham (United Kingdom)

    2000-06-15

    The papers from the first international conference on Friction Stir Welding (FSW) have been reviewed. Taken together the papers provide a very optimistic picture for the development and application of friction stir welding in general and to the case of the copper canister in particular. Whilst a considerable development effort is in progress the process has been industrialised for joining of aluminium sheet and it is accepted by Lloyds register for this purpose. Development of procedures and equipment to weld thicker materials and a wider range of materials is progressing ahead of the research activity to aid the understanding of the process at this stage. Nevertheless, well-established weld assessment procedures are being applied to experimental welds with very encouraging results. Summaries of the key papers are presented in an appendix.

  2. Neurological risks associated with manganese exposure from welding operations--a literature review.

    Science.gov (United States)

    Flynn, Michael R; Susi, Pam

    2009-09-01

    Exposure to manganese dusts and fumes may cause a clinical neurological syndrome called manganism. Welders are frequently exposed to manganese-containing fumes generated by electric arcs and thermal torches. This paper reviews studies on the association between exposure to such welding fumes and neurological disease. Using the IRSST expert panel criteria, 78 cases of probable/possible, and 19 additional cases of possible occupational manganism were identified in the literature among manganese-exposed workers involved in welding processes. Epidemiological evidence linking welding exposures to Parkinson's disease is still controversial. Although more research is needed to clarify the risks of neurological impairment from welding, control measures including ventilation and adequate respiratory protection, should be implemented to minimize welding fume exposures. The significance of fume transport into the central nervous system via the olfactory nerve, which by-passes the blood-brain barrier, also needs to be assessed.

  3. Modern fiber laser beam welding of the newly-designed precipitation-strengthened nickel-base superalloys

    Science.gov (United States)

    Naffakh Moosavy, Homam; Aboutalebi, Mohammad-Reza; Seyedein, Seyed Hossein; Goodarzi, Massoud; Khodabakhshi, Meisam; Mapelli, Carlo; Barella, Silvia

    2014-04-01

    In the present research, the modern fiber laser beam welding of newly-designed precipitation-strengthened nickel-base superalloys using various welding parameters in constant heat input has been investigated. Five nickel-base superalloys with various Ti and Nb contents were designed and produced by Vacuum Induction Melting furnace. The fiber laser beam welding operations were performed in constant heat input (100 J mm-2) and different welding powers (400 and 1000 W) and velocities (40 and 100 mm s-1) using 6-axis anthropomorphic robot. The macro- and micro-structural features, weld defects, chemical composition and mechanical property of 3.2 mm weldments were assessed utilizing optical and scanning electron microscopes equipped with EDS analysis and microhardness tester. The results showed that welding with higher powers can create higher penetration-to-width ratios. The porosity formation was increased when the welding powers and velocities were increased. None of the welds displayed hot solidification and liquation cracks in 400 and 1000 W welding powers, but liquation phenomenon was observed in all the heat-affected zones. With increasing the Nb content of the superalloys the liquation length was increased. The changing of the welding power and velocity did not alter the hardness property of the welds. The hardness of welds decreased when the Ti content declined in the composition of superalloys. Finally, the 400 and 1000 W fiber laser powers with velocity of 40 and 100 m ms-1 have been offered for hot crack-free welding of the thin sheet of newly-designed precipitation-strengthened nickel-base superalloys.

  4. On the use of slag from silicomanganese production for welding flux manufacturing

    Science.gov (United States)

    Kozyrev, N. A.; Kryukov, R. E.; Lipatova, U. I.; Kozyreva, O. E.

    2016-09-01

    The technologies for manufacturing of welding fluxes with the use of slag from silicomanganese production and dust of gas purification from aluminum production are developed. The new compositions and production technology of welding fluxes are offered. The comparative evaluation of the new compositions and widely used AN-348 flux is provided. It is shown that the quality of submerged arc welding with the use of the developed flux composition is significantly better than the submerged arc welding with AN-348 flux. The effect of fractional composition on high-quality performance of the weld is investigated. The macro- and microstructures, nonmetallic inclusions and the mechanical properties of the weld are examined. It is shown that the introduction of carbon-fluorine containing additive into the flux, based on the dust of gas purification from aluminum production, can significantly improve the whole complex of mechanical properties of the weld, especially characteristics of impact hardness at low temperatures. The conducted research served as a basis for development of submerged arc welding technologies protected by the patents of the Russian Federation.

  5. Overview on the welding technologies of CLAM steel and the DFLL TBM fabrication

    Directory of Open Access Journals (Sweden)

    Junyu Zhang

    2016-12-01

    Full Text Available Dual Functional Lithium Lead (DFLL blanket was proposed for its advantages of high energy exchange efficiency and on-line tritium extraction, and it was selected as the candidate test blanket module (TBM for China Fusion Engineering Test Reactor (CFETR and the blanket for Fusion Design Study (FDS series fusion reactors. Considering the influence of high energy fusion neutron irradiation and high heat flux thermal load on the blanket, China Low Activation Martensitic (CLAM steel was selected as the structural material for DFLL blanket. The structure of the blanket and the cooling internal components were pretty complicated. Meanwhile, high precision and reliability were required in the blanket fabrication. Therefore, several welding techniques, such as hot isostatic pressing diffusion bonding, tungsten inner gas welding, electron beam welding and laser beam welding were developed for the fabrication of cooling internals and the assembly of the blanket. In this work, the weldability on CLAM steel by different welding methods and the properties of as-welded and post-weld heat-treated joints were investigated. Meanwhile, the welding schemes and the assembly strategy for TBM fabrication were raised. Many tests and research efforts on scheme feasibility, process standardization, component qualification and blanket assembly were reviewed.

  6. The high frequency characteristics of laser reflection and visible light during solid state disk laser welding

    Science.gov (United States)

    Gao, Xiangdong; You, Deyong; Katayama, Seiji

    2015-07-01

    Optical properties are related to weld quality during laser welding. Visible light radiation generated from optical-induced plasma and laser reflection is considered a key element reflecting weld quality. An in-depth analysis of the high-frequency component of optical signals is conducted. A combination of a photoelectric sensor and an optical filter helped to obtain visible light reflection and laser reflection in the welding process. Two groups of optical signals were sampled at a high sampling rate (250 kHz) using an oscilloscope. Frequencies in the ranges 1-10 kHz and 10-125 kHz were investigated respectively. Experimental results showed that there was an obvious correlation between the high-frequency signal and the laser power, while the high-frequency signal was not sensitive to changes in welding speed. In particular, when the defocus position was changed, only a high frequency of the visible light signal was observed, while the high frequency of the laser reflection signal remained unchanged. The basic correlation between optical features and welding status during the laser welding process is specified, which helps to provide a new research focus for investigating the stability of welding status.

  7. Laser welding study for further development in essential power plant part repairs

    Directory of Open Access Journals (Sweden)

    Isarawit Chaopanich

    2015-06-01

    Full Text Available The objective of this research work was to study the effects of laser welding when compared with shield metal arc welding (SMAW process on the heat input, welded deposit rate, residual stress, distortion, microstructure and micro hardness. The martensitic stainless steel grade 431 specimens were overlay welded with the stainless steel filler metals. From the results, the heat input of 0.26 kJ/mm in laser welding calculated was significantly lower than that of 1.66 kJ/mm in SMAW, and contributed to low level residual stress, minimal distortion, very small penetration depth and heat affected zone (HAZ of less than 100 µm. The micro hardness results indicated that the maximum value from laser welding in the HAZ was 370.2 HV lower than the value from SMAW of 525.5 HV. The welded deposit rate for laser welding was with 26.5 mm3 /min remarkably lower than the rate for SMAW of 1,800 mm3 /min.

  8. Numerical analysis of weld pool for galvanized steel with lap joint in GTAW

    Energy Technology Data Exchange (ETDEWEB)

    Jeong, Hunchul; Park, Kyungbae; Kim, Yougjun; Cho, Jungho [Chungbuk National University, Cheongju (Korea, Republic of); Kim, Dong-Yoon; Kang, Moon-Jin [Korea Institute of Industrial Technology, Incheon (Korea, Republic of)

    2017-06-15

    Galvanized steel is widely used and its demand is growing in automotive industry due to high quality requirement for corrosion resistance. Although there are a lot of demands on using galvanized steel as automotive parts especially for outer body, it has a grave flaw in its welding process. The difficulty is low weldability due to various defects such as porosities and blow holes in weldment, which occurred during welding. A solution to prevent these defects is using hybrid welding process, with two more welding processes. One of the hybrid solutions is using Gas tungsten arc welding (GTAW) as leading position in order to remove the zinc (Zn) coating on the surface before the followed practical fusion welding process. In this research, a numerical analysis model which can predict the eliminated Zn coated layers and the area of Fusion zone (FZ). Developed numerical analysis model was validated through comparing experiment to simulation. Basically, arc heat flux, arc pressure, electromagnetic force and Marangoni flow were employed as the boundary conditions and body force terms. Governing equations such as the continuity, momentum, Volume of fluid (VOF) and energy equations were adopted as usual. In addition to previous model, concentrated arc heat flux and contact thermal conductance models are newly suggested and showed successful result. They are adopted to realize edge concentrated arc and interfacial thermal conductance in lap joint fillet arc welding. Developed numerical analysis model successfully simulated the weld pool and temperature profile therefore the predicted Zn removed area considerably coincided with experimental result.

  9. Development of the new physical method for real time spot weld quality evaluation using ultrasound

    Science.gov (United States)

    Chertov, Andriy M.

    Since the invention of resistance spot welding, the manufacturers have been concerned about the quality assurance of the joints. One of the most promising directions in quality inspection is the real time ultrasonic nondestructive evaluation. In such a system, the acoustic signals are sent through the spot weld during welding and then analyzed to characterize the quality of the joint. Many research groups are currently working to develop a reliable inspection method. In this dissertation the new physical method of resistance spot weld quality monitoring is presented. It differs from all other ultrasonic methods by the physical principles of inspection. The multilayered structure of the spot weld with varying physical properties is investigated with short pulses of longitudinal ultrasonic waves. Unlike other methods, the developed technology works in reflection mode. The waves bring back the information which, after careful analysis, can be used to evaluate the weld quality. The complex structure of the weldment modifies the waves in different ways which, makes it hard to accurately measure the physical properties of the weldment. The frequency-dependent attenuation of the sound, diffraction, and beam divergence - all contribute to the signal distraction. These factors are fully studied, and ways to minimize them are presented. After application of pattern recognition routines, the weld characteristics are submitted to fuzzy logic algorithm, and the weld is characterized. The current level of the system development allowed the installation of two prototype machines at one assembly plant. The technology is now under thorough evaluation for robustness and accuracy in an industrial environment.

  10. A comparison of the physics of Gas Tungsten Arc Welding (GTAW), Electron Beam Welding (EBW), and Laser Beam Welding (LBW)

    Science.gov (United States)

    Nunes, A. C., Jr.

    1985-01-01

    The physics governing the applicability and limitations of gas tungsten arc (GTA), electron beam (EB), and laser beam (LB) welding are compared. An appendix on the selection of laser welding systems is included.

  11. Upgraded HFIR Fuel Element Welding System

    Energy Technology Data Exchange (ETDEWEB)

    Sease, John D [ORNL

    2010-02-01

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

  12. A study of processes for welding pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Weston, J. (ed.)

    1991-07-01

    A review was made of exisiting and potential processes for welding pipelines: fusion welding (arc, electron beam, laser, thermit) and forge welding (friction, flash, magnetically impelled arc butt, upset butt, explosive, shielded active gas, gas pressure). Consideration of J-lay operations gave indications that were reflections of the status of the processes in terms of normal land and offshore S-lay operation: forge welding processes, although having promise require considerable development; fusion welding processes offer several possibilities (mechanized GMA welding likely to be used in 1991-2); laser welding requires development in all pipeline areas: a production machine for electron beam welding will involve high costs. Nondestructive testing techniques are also reviewed. Demand for faster quality assessment is being addressed by speeding radiographic film processing and through the development of real time radiography and automatic ultrasonic testing. Conclusions on most likely future process developments are: SMAW with cellulosic electrodes is best for tie-ins, short pip runs; SMAW continues to be important for small-diameter lines, although mechanized GMA could be used, along with mechanical joining, MIAB, radial fraction, and flash butt; mechanized GMA welding is likely to predominate for large diameter lines and probably will be used for the first J-lay line (other techniques could be used too); and welding of piping for station facilities involves both shop welding of sub-assemblies and on-site welding of pipe and sub-assemblies to each other (site welding uses both SMAW and GMAW). Figs, tabs.

  13. A Survey on Friction Stir Welding Of Dissimilar Magnesium Alloys

    Science.gov (United States)

    Unnikrishnan, M. A.; Raja, Dhas. J. Edwin

    2017-10-01

    There is a consistent demand for superior materials in every industry. The areas on demand are automobile and aerospace sectors in major.. The most commonly used material in these fields is Aluminium.Though it possess all the properties up to some extent constant demand is pushing for alternate materials. Dissimilar alloys have been a relatively new approach towards these fields.. Friction stir welding dissimilar alloys is a big leap in Automobile sector. In this paper a detailed review of Friction stir welding of Dissimilar Magnesium alloys has been done. This work will serve as a reference to subsequent researchers.

  14. Economic evaluation for use of advanced welding equipment

    Science.gov (United States)

    Petrov, P. Y.; Alekseev, I. V.; Kolesnik, E. A.

    2017-10-01

    Stable and sustainable predicted development of industrial enterprises within global competition is ensured by regular improvement of technologies and introduction of innovative technological equipment. In terms of comparative analysis of the various power supplies application in the welding production, the equality of relative resource efficiency of various equipment and specific economic effect has been calculated. The research showed that the costs per 1 meter are the smallest for semiautomatic welding in a protective gas environment using inverter power supplies, contributing to the economic benefit during its application.

  15. Numerical simulation of electron beam welding with beam oscillations

    Science.gov (United States)

    Trushnikov, D. N.; Permyakov, G. L.

    2017-02-01

    This research examines the process of electron-beam welding in a keyhole mode with the use of beam oscillations. We study the impact of various beam oscillations and their parameters on the shape of the keyhole, the flow of heat and mass transfer processes and weld parameters to develop methodological recommendations. A numerical three-dimensional mathematical model of electron beam welding is presented. The model was developed on the basis of a heat conduction equation and a Navier-Stokes equation taking into account phase transitions at the interface of a solid and liquid phase and thermocapillary convection (Marangoni effect). The shape of the keyhole is determined based on experimental data on the parameters of the secondary signal by using the method of a synchronous accumulation. Calculations of thermal and hydrodynamic processes were carried out based on a computer cluster, using a simulation package COMSOL Multiphysics.

  16. SORPAS – The Professional Software for Simulation of Resistance Welding

    DEFF Research Database (Denmark)

    Zhang, Wenqi

    2002-01-01

    Based on long time engineering research and dedicated collaborations with industry, the professional welding software, SORPAS, has been developed for simulation of resistance projection and spot welding processes applying the powerful finite element method (FEM). In order to make the software...... directly usable by engineers and technicians in industry, all of the important parameters in resistance welding are considered and automatically implemented into the software. With the specially designed graphic user interface for Windows, engineers (even without prior knowledge of FEM) can quickly learn...... and easily operate and utilize the software. With the user-friendly facilities for flexible geometric design of work pieces and electrodes as well as process parameter settings similar to real machine parameter settings, the software has been readily applied in industry for supporting product development...

  17. Multiaxial fatigue of aluminium friction stir welded joints: preliminary results

    Directory of Open Access Journals (Sweden)

    D. G. Hattingh

    2015-07-01

    Full Text Available The aim of the present research is to check the accuracy of the Modified Wöhler Curve Method (MWCM in estimating the fatigue strength of friction stir (FS welded tubular joints of Al 6082-T6 subjected to in-phase and out-of-phase multiaxial fatigue loading. The welded samples being investigated were manufactured by equipping an MTS I-STIR process development system with a retracting tool that was specifically designed and optimised for this purpose. These specimens were tested under proportional and non-proportional tension and torsion, the effect of non-zero mean stresses being also investigated. The validation exercise carried out by using the generated experimental results allowed us to prove that the MWCM (applied in terms of nominal stresses is highly accurate in predicting the fatigue strength of the tested FS welded joints, its usage resulting in estimates falling with the uniaxial and torsional calibration scatter bands.

  18. Weld procedure produces quality welds for thick sections of Hastelloy-X

    Science.gov (United States)

    Flens, F. J.; Fletcher, C. W.; Glasier, L. F., Jr.

    1967-01-01

    Welding program produces premium quality, multipass welds in heavy tube sections of Hastelloy-X. It develops semiautomatic tungsten/inert gas procedures, weld wire procurement specifications material weld properties, welder-operator training, and nondestructive testing inspection techniques and procedures.

  19. Laser welding of aluminium-magnesium alloys sheets process optimization and welds characterization

    Energy Technology Data Exchange (ETDEWEB)

    Mayer, C. [GEMPPM (CALFETMAT), 69 - Villeurbanne (France); Fouquet, F. [GEMPPM (CALFETMAT), 69 - Villeurbanne (France); Robin, M. [GEMPPM (CALFETMAT), 69 - Villeurbanne (France)

    1996-12-31

    The purpose of the present study was to obtain good quality welds using a CO2 laser with Al-Mg alloys sheet. Defects formation mechanisms were analyzed and a welding procedure was defined, using several characterization technics, in order to realize low defects welding seams. After laser welding optimization, comparative tensile tests and microstructural analysis were carried out. (orig.)

  20. 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

  1. Theoretical and experimental contributions regarding the impact on work environment of welding processes in MIG / MAG protective gas medium

    Directory of Open Access Journals (Sweden)

    Gh. Amza

    2013-07-01

    Full Text Available This paper presents the main factors that cause environmental pollution in the case of the welding procedure in a protective gas environment. In the research the MIG and MAG welding processes were taken into account. The materials used in the experiments were 8TiCr170 stainless steel as the base material and as filler materials 4 types of welding wires were used, characterized by different chemical compositions. To assess the impact on the work environment of such welding processes the pollution coefficient Cp was defined based on the material balance equation as the ratio of the mass of all materials used in the welding process Mt and the effective mass of the welded performed Mu.

  2. Hexavalent chromium exposure and control in welding tasks.

    Science.gov (United States)

    Meeker, John D; Susi, Pam; Flynn, Michael R

    2010-11-01

    Studies of exposure to the lung carcinogen hexavalent chromium (CrVI) from welding tasks are limited, especially within the construction industry where overexposure may be common. In addition, despite the OSHA requirement that the use of engineering controls such as local exhaust ventilation (LEV) first be considered before relying on other strategies to reduce worker exposure to CrVI, data on the effectiveness of LEV to reduce CrVI exposures from welding are lacking. The goal of the present study was to characterize breathing zone air concentrations of CrVI during welding tasks and primary contributing factors in four datasets: (1) OSHA compliance data; (2) a publicly available database from The Welding Institute (TWI); (3) field survey data of construction welders collected by the Center for Construction Research and Training (CPWR); and (4) controlled welding trials conducted by CPWR to assess the effectiveness of a portable LEV unit to reduce CrVI exposure. In the OSHA (n = 181) and TWI (n = 124) datasets, which included very few samples from the construction industry, the OSHA permissible exposure level (PEL) for CrVI (5 μg/m(3)) was exceeded in 9% and 13% of samples, respectively. CrVI concentrations measured in the CPWR field surveys (n = 43) were considerably higher, and 25% of samples exceeded the PEL. In the TWI and CPWR datasets, base metal, welding process, and LEV use were important predictors of CrVI concentrations. Only weak-to-moderate correlations were found between total particulate matter and CrVI, suggesting that total particulate matter concentrations are not a good surrogate for CrVI exposure in retrospective studies. Finally, in the controlled welding trials, LEV reduced median CrVI concentrations by 68% (p = 0.02). In conclusion, overexposure to CrVI in stainless steel welding is likely widespread, especially in certain operations such as shielded metal arc welding, which is commonly used in construction. However, exposure could be

  3. Supplements for exotic pets.

    Science.gov (United States)

    Mejia-Fava, Johanna; Colitz, Carmen M H

    2014-09-01

    The use of supplements has become commonplace in an effort to complement traditional therapy and as part of long-term preventive health plans. This article discusses historical and present uses of antioxidants, vitamins, and herbs. By complementing traditional medicine with holistic and alternative nutrition and supplements, the overall health and wellness of exotic pets can be enhanced and balanced. Further research is needed for understanding the strengths and uses of supplements in exotic species. Going back to the animals' origin and roots bring clinicians closer to nature and its healing powers. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Nitrogen And Oxygen Amount In Weld After Welding With Micro-Jet Cooling

    Directory of Open Access Journals (Sweden)

    Węgrzyn T.

    2015-06-01

    Full Text Available Micro-jet cooling after welding was tested only for MIG welding process with argon, helium and nitrogen as a shielded gases. A paper presents a piece of information about nitrogen and oxygen in weld after micro-jet cooling. There are put down information about gases that could be chosen both for MIG/MAG welding and for micro-jet process. There were given main information about influence of various micro-jet gases on metallographic structure of steel welds. Mechanical properties of weld was presented in terms of nitrogen and oxygen amount in WMD (weld metal deposit.

  5. Supplemental Colleges

    Data.gov (United States)

    Department of Homeland Security — The Supplemental Colleges layer attempts to capture additional Post Secondary Education campuses of colleges and universities associated with a single campus listed...

  6. Effects of welding parameters on the mechanical properties of inert gas welded 6063 Aluminium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ertan, Taner [MAKO Corporation (Turkey); Uguz, Agah [Uludag Univ. (Turkey). Mechnical Engineering Dept.; Ertan, Rukiye

    2012-07-01

    The influence of welding parameters, namely welding current and gas flow rate, on the mechanical properties of Gas Tungsten Arc Welding (GTAW) and Shielded Metal Arc Welding (SMAW) welded 6063 Aluminum alloy (AA 6063) has been investigated. In order to study the effect of the welding current and gas flow rate, microstructural examination, hardness measurements and room temperature tensile tests have been carried out. The experimental results show that the mechanical properties of GTAW welded joints have better mechanical properties than those of SMAW welded joints. Increasing the welding current appeared to have a beneficial effect on the mechanical properties. However, either increasing or decreasing the gas flow rate resulted in a decrease of hardness and tensile strength. It was also found that, the highest strength was obtained in GTAW welded samples at 220 A and 15 l/min gas flow rate.

  7. Strength analysis of welded corners of PVC window profiles

    Science.gov (United States)

    Postawa, P.; Stachowiak, T.; Gnatowski, A.

    2017-08-01

    The article presents the results of researches which main purpose was to define the influence of welding parameters on strength of welded corners of PVC window profile. PVC profiles of a branded name GENEO® produced by Rehau Company were used for this research. The profiles were made by using a co-extrusion method. The surface of the profile was made of PVC mixture with no additives. Its main task was to get a smooth surface resistant to a smudge. The use of an unfilled polyester provides an aesthetic look and improves the resistance of extrudate to water getting into inner layers. The profile's inner layers have been filled up with glass fibre in order to improve its stiffness and mechanical properties. Window frames with cut corners used for this research, were produced on technological line of EUROCOLOR Company based in Pyskowice (Poland). The main goal of this analysis was to evaluate the influence of the main welding parameter (temperature upsetting) on hardness of welds we received in whole process. A universal testing machine was used for the research.

  8. production of manual arc welding electrodes with local raw materials

    African Journals Online (AJOL)

    CHUKSSUCCESS 4 LOVE

    formulated to satisfy three major objectives: to form fusible slags, to stabilize the arc and to produce an inert gas shielding during welding. In the research carried out, several flux samples of various local raw materials were collected, their chemical compositions were determined and the results utilized in producing manual ...

  9. Fatigue classification of welded joints in orthotropic steel bridge decks

    NARCIS (Netherlands)

    Kolstein, M.H.

    2007-01-01

    This dissertation presents the research into fatigue classifications of welded joints in orthotropic steel bridge decks. These classifications are needed to calculate the fatigue life of these joints and should be included in the design codes. For years bridge design was mainly based on static

  10. Electron Gun for Computer-controlled Welding of Small Components

    Czech Academy of Sciences Publication Activity Database

    Dupák, Jan; Vlček, Ivan; Zobač, Martin

    2001-01-01

    Roč. 62, 2-3 (2001), s. 159-164 ISSN 0042-207X R&D Projects: GA AV ČR IBS2065015 Institutional research plan: CEZ:AV0Z2065902 Keywords : Electron beam-welding machine * Electron gun * Computer- control led beam Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.541, year: 2001

  11. Automatic monitoring of vibration welding equipment

    Science.gov (United States)

    Spicer, John Patrick; Chakraborty, Debejyo; Wincek, Michael Anthony; Wang, Hui; Abell, Jeffrey A; Bracey, Jennifer; Cai, Wayne W

    2014-10-14

    A vibration welding system includes vibration welding equipment having a welding horn and anvil, a host device, a check station, and a robot. The robot moves the horn and anvil via an arm to the check station. Sensors, e.g., temperature sensors, are positioned with respect to the welding equipment. Additional sensors are positioned with respect to the check station, including a pressure-sensitive array. The host device, which monitors a condition of the welding equipment, measures signals via the sensors positioned with respect to the welding equipment when the horn is actively forming a weld. The robot moves the horn and anvil to the check station, activates the check station sensors at the check station, and determines a condition of the welding equipment by processing the received signals. Acoustic, force, temperature, displacement, amplitude, and/or attitude/gyroscopic sensors may be used.

  12. Experimental and simulated strength of spot welds

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Bennedbæk, Rune A.K.; Larsen, Morten B.

    2014-01-01

    Weld strength testing of single spots in DP600 steel is presented for the three typical testing procedures, i.e. tensile-shear, cross-tension and peel testing. Spot welds are performed at two sets of welding parameters and strength testing under these conditions is presented by load......-elongation curves revealing the maximum load and the elongation at break. Welding and strength testing is simulated by SORPAS® 3D, which allows the two processes to be prepared in a combined simulation, such that the simulated welding properties are naturally applied to the simulation of strength testing. Besides...... the size and shape of the weld nugget, these properties include the new strength of the material in the weld and the heat affected zone based on the predicted hardness resulting from microstructural phase changes simulated during cooling of the weld before strength testing. Comparisons between overall...

  13. Design of welded aluminium connections (Entwurf und Berechnung von Aluminium Schweissverbindungen)

    NARCIS (Netherlands)

    Soetens, F.

    1998-01-01

    In the past two decades considerable research effort has been put into welded aluminium connections in order to better understand their structural behaviour and to up-date the design rules in the existing standards at the time [1].

  14. Underwater Wet Repair Welding of API 5L X65M Pipeline Steel

    National Research Council Canada - National Science Library

    Grzegorz Rogalski; Dariusz Fydrych; Jerzy Łabanowski

    2017-01-01

    This paper presents results of the research of effect of polymer insulation of pipeline made of API 5L X65M steel as well as underwater wet welding parameters on properties of joints made by covered electrodes...

  15. Effects of Metal Types on Residual Stress in Electron-Beam Welding Joints with Sheet Metals

    National Research Council Canada - National Science Library

    Nagai, Takuya; Kasai, Ryu; Ueno, Kunika; Mochizuki, Masahito; Suga, Tetsuo

    2015-01-01

    The effect of metal types on the residual stresses has been researched through X-ray stress measurement for the electron-beam welding joints made of sheet metals with a thickness of approximately 10 mm...

  16. Vitamin Supplement - Editorial

    OpenAIRE

    Jakobsen, Jette; Bysted, Anette

    2012-01-01

    This Vitamin Supplement presents some of the main information presented at The First International Vitamin Conference in Copenhagen, May, 2010. The theme of the conference was ‘Vitamins in foods and supplements: Analytical possibilities versus nutritional needs in human research, food databases, and labeling’. All 13 vitamins were represented. Although vitamin D and folate that in recent years have been heavily debated, also were the one in focus and is represented in 8 of the 17 papers inclu...

  17. Thermal treatment of dissimilar steels' welded joints

    Science.gov (United States)

    Nikulina, A. A.; Denisova, A. S.; Gradusov, I. N.; Ryabinkina, P. A.; Rushkovets, M. V.

    2016-04-01

    In this paper combinations of chrome-nickel steel and high-carbon steel, produced by flash butt welding after heat treatment, are investigated. Light and electron microscopic studies show that the welded joints after heat treatment have a complex structure consisting of several phases as initial welded joints. A martensite structure in welded joints after thermal treatment at 300... 800 °C has been found.

  18. Closed circuit television welding alignment system

    Energy Technology Data Exchange (ETDEWEB)

    Darner, G.S.

    1976-09-01

    Closed circuit television (CCTV) weld targeting systems were developed to provide accurate and repeatable positioning of the electrode of an electronic arc welder with respect to the parts being joined. A sliding mirror electrode holder was developed for use with closed circuit television equipment on existing weld fixturing. A complete motorized CCTV weld alignment system was developed to provide weld targeting for even the most critical positioning requirements.

  19. Preventing Contamination In Electron-Beam Welds

    Science.gov (United States)

    Goodin, Wesley D.; Gulbrandsen, Kevin A.; Oleksiak, Carl

    1990-01-01

    Simple expedient eliminates time-consuming, expensive manual hand grinding. Use of groove and backup tube greatly reduces postweld cleanup in some electron-beam welding operations. Tube-backup method developed for titanium parts, configurations of which prevents use of solid-block backup. In new welding configuration, tube inserted in groove to prevent contact between alumina beads and molten weld root. When welding complete and beads and tube removed, only minor spatter remains and is ground away easily.

  20. Performance of mesh seam welds in tailor welded blanks; Terado blank yo mash seam yosetsubu no tokusei

    Energy Technology Data Exchange (ETDEWEB)

    Uchihara, M.; Takahashi, M.; Kurita, M.; Hirose, Y.; Fukui, K. [Sumitomo Metal Industries, Ltd., Osaka (Japan)

    1997-10-01

    Formability, fatigue properties and corrosion behavior of mash seam welded steel sheets were investigated and the results were compared with laser weld. The stretch formability of mash seam weld and laser weld were same level. Mash seam weld however, showed slightly smaller formability in hole expansion test. The fatigue strength of mash seam welds was lower than that of laser welds in case of differential thickness joints. Corrosion was apt to initiate at weld in both mash seam and laser weld with E-coat. The corrosion resistance of welds was improved by using zinc coated steel. 3 refs., 14 figs., 2 tabs.

  1. Comparative study on laser welding and TIG welding of semi-solid high pressure die cast A356 aluminium alloy

    CSIR Research Space (South Africa)

    Govender, G

    2007-07-01

    Full Text Available components. The low porosity levels in SSM high pressure die castings (HPDC) improves the weldability of these components. The aim of the current research was to perform a comparative study of laser and TIG welding of SSM HPDC aluminium alloy A356. SSM...

  2. 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.

  3. 49 CFR 195.224 - Welding: Weather.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Welding: Weather. 195.224 Section 195.224 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY... PIPELINE Construction § 195.224 Welding: Weather. Welding must be protected from weather conditions that...

  4. 49 CFR 179.100-9 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.100-9 Section 179.100-9... Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-9 Welding. (a) All..., appendix W (IBR, see § 171.7 of this subchapter). Welding procedures, welders and fabricators shall be...

  5. 49 CFR 179.220-10 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.220-10 Section 179.220-10... Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-10 Welding. (a) All joints... of this subchapter). Welding procedures, welders, and fabricators shall be approved. (b) Radioscopy...

  6. 49 CFR 179.400-11 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.400-11 Section 179.400-11...-11 Welding. (a) Except for closure of openings and a maximum of two circumferential closing joints in... subchapter). (d) Each welding procedure, welder, and fabricator must be approved. [Amdt. 179-32, 48 FR 27708...

  7. 49 CFR 179.200-10 - Welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding. 179.200-10 Section 179.200-10... Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-10 Welding. (a) All joints... W (IBR, see § 171.7 of this subchapter). Welding procedures, welders and fabricators shall be...

  8. 30 CFR 77.408 - Welding operations.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding operations. 77.408 Section 77.408 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH... for Mechanical Equipment § 77.408 Welding operations. Welding operations shall be shielded and the...

  9. 30 CFR 75.1729 - Welding operations.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Welding operations. 75.1729 Section 75.1729 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR COAL MINE SAFETY AND HEALTH MANDATORY SAFETY STANDARDS-UNDERGROUND COAL MINES Miscellaneous § 75.1729 Welding operations. Welding...

  10. Friction welding thermal and metallurgical characteristics

    CERN Document Server

    Yilbas, Bekir Sami

    2014-01-01

    This book provides insight into the thermal analysis of friction welding incorporating welding parameters such as external, duration, breaking load, and material properties. The morphological and metallurgical changes associated with the resulting weld sites are analysed using characterization methods such as electron scanning microscope, energy dispersive spectroscopy, X-ray Diffraction, and Nuclear reaction analysis.

  11. Welding Using Chilled-Inert-Gas Purging

    Science.gov (United States)

    Mcgee, William F.; Rybicki, Daniel J.

    1995-01-01

    Report describes study of fusion welding using chilled inert gas. Marked improvement shown in welding of aluminum using chilled helium gas. Chilling inert gas produces two additional benefits: 1) creation of ultradense inert atmosphere around welds; 2) chilled gas cools metal more quickly down to temperature at which metals not reactive.

  12. 49 CFR 179.11 - Welding certification.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Welding certification. 179.11 Section 179.11 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY... Design Requirements § 179.11 Welding certification. (a) Welding procedures, welders and fabricators shall...

  13. 46 CFR 154.665 - Welding procedures.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Welding procedures. 154.665 Section 154.665 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS... Construction § 154.665 Welding procedures. Welding procedure tests for cargo tanks for a design temperature...

  14. Low Speed Control for Automatic Welding

    Science.gov (United States)

    Iceland, W. E.

    1982-01-01

    Amplifier module allows rotating positioner of automatic welding machine to operate at speeds below normal range. Low speeds are precisely regulated by a servomechanism as are normal-range speeds. Addition of module to standard welding machine makes it unnecessary to purchase new equipment for low-speed welding.

  15. 49 CFR 195.214 - Welding procedures.

    Science.gov (United States)

    2010-10-01

    ... accordance with welding procedures qualified under Section 5 of API 1104 or Section IX of the ASME Boiler and Pressure Vessel Code (incorporated by reference, see § 195.3) . The quality of the test welds used to... 49 Transportation 3 2010-10-01 2010-10-01 false Welding procedures. 195.214 Section 195.214...

  16. Welding multiple plies with an electron beam

    Science.gov (United States)

    Kiluk, F. J.

    1980-01-01

    Method for electron-beam welding of multi-ply metal sheets eliminates ply separation and minimizes porosity. Method was developed for assembling bellows made of four plies of iron/nickel alloy sheets. Method consists of making successive stitch welds with electron beam until weld seam is completely filled in and all plies have been penetrated.

  17. Viewing electron-beam welds in progress

    Science.gov (United States)

    Armenoff, C. T.

    1980-01-01

    With aid of optical filter, operator of electron-beam welding machine can view TV image of joint that is being welded and can make corrections as necessary. Operator can see when weld bead gets out of alinement, for example, and compensate for deflection of electron beam caused by changes in magnetic field.

  18. [Dental welding titanium and its clinical usage].

    Science.gov (United States)

    Li, H; Xiao, M; Zhao, Y

    1998-09-01

    Due to its excellent biocompatibility, desirable chemical and mechanical properties, Titanium has been used for implant denture, RPD and FPD, where welding techniques were indispensable. This paper introduces 5 useful modern ways to weld Titanium and their clinical usage. They are: laser, plasma welding, TIG, infraned brazing and Hruska electrowelding.

  19. Technology of welding aluminum alloys-III

    Science.gov (United States)

    Harrison, J. R.; Kor, L. J.; Oleksiak, C. E.

    1978-01-01

    Control of porosity in weld beads was major objective in development of aluminum welding program. Porosity, most difficult defect to control, is caused by hydrogen gas unable to escape during solidification. Hard tooling allows hotter bead than free-fall tooling so hydrogen bubbles can boil out instead of forming pores. Welding position, moisture, and cleanliness are other important factors in control of porosity.

  20. Laser weld process monitoring and control using chromatic filtering of thermal radiation from a weld pool

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Cheol Jung; Kim, Min Suk; Baik, Sung Hoon; Chung, Chin Man

    2000-06-01

    The application of high power Nd: YAG lasers for precision welding in industry has been growing quite fast these days in diverse areas such as the automobile, the electronics and the aerospace industries. These diverse applications also require the new developments for the precise control and the reliable process monitoring. Due to the hostile environment in laser welding, a remote monitoring is required. The present development relates in general to weld process monitoring techniques, and more particularly to improved methods and apparatus for real-time monitoring of thermal radiation of a weld pool to monitor a size variation and a focus shift of the weld pool for weld process control, utilizing the chromatic aberration of focusing lens or lenses. The monitoring technique of the size variation and the focus shift of a weld pool is developed by using the chromatic filtering of the thermal radiation from a weld pool. The monitoring of weld pool size variation can also be used to monitor the weld depth in a laser welding. Furthermore, the monitoring of the size variation of a weld pool is independent of the focus shift of a weld pool and the monitoring of the focus shift of a weld pool is independent of the size variation of a weld pool.

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

    Science.gov (United States)

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

    2009-11-01

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

  2. Dietary Supplements

    Science.gov (United States)

    ... keeping bones strong. Pregnant women can take the vitamin folic acid to prevent certain birth defects in their babies. To take a supplement as safely as possible Tell your health care provider about any dietary supplements you use Do not take a bigger dose ...

  3. Collision Welding of Dissimilar Materials by Vaporizing Foil Actuator: A Breakthrough Technology for Dissimilar Metal Joining

    Energy Technology Data Exchange (ETDEWEB)

    Daehn, Glenn S. [The Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering; Vivek, Anupam [The Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering; Liu, Bert C. [The Ohio State Univ., Columbus, OH (United States). Dept. of Materials Science and Engineering

    2016-09-30

    This work demonstrated and further developed Vaporizing Foil Actuator Welding (VFAW) as a viable technique for dissimilar-metal joining for automotive lightweighting applications. VFAW is a novel impact welding technology, which uses the pressure developed from electrically-assisted rapid vaporization of a thin aluminum foil (the consumable) to launch and ultimately collide two of more pieces of metal to create a solid-state bond between them. 18 dissimilar combinations of automotive alloys from the steel, aluminum and magnesium alloy classes were screened for weldability and characterized by metallography of weld cross sections, corrosion testing, and mechanical testing. Most combinations, especially a good number of Al/Fe pairs, were welded successfully. VFAW was even able to weld combinations of very high strength materials such as 5000 and 6000 series aluminum alloys to boron and dual phase steels, which is difficult to impossible by other joining techniques such as resistance spot welding, friction stir welding, or riveting. When mechanically tested, the samples routinely failed in a base metal rather than along the weld interface, showing that the weld was stronger than either of the base metals. As for corrosion performance, a polymer-based protective coating was used to successfully combat galvanic corrosion of 5 Al/Fe pairs through a month-long exposure to warm salt fog. In addition to the technical capabilities, VFAW also consumes little energy compared to conventional welding techniques and requires relatively light, flexible tooling. Given the technical and economic advantages, VFAW can be a very competitive joining technology for automotive lightweighting. The success of this project and related activities has resulted in substantial interest not only within the research community but also various levels of automotive supply chain, which are collaborating to bring this technology to commercial use.

  4. Effects of welding fumes on nuclear air cleaning system carbon adsorber banks

    Energy Technology Data Exchange (ETDEWEB)

    Roberson, P.W. [Duke Power Company, Huntersville, NC (United States)

    1997-08-01

    Standard Technical Specifications for nuclear air cleaning systems include requirements for surveillance tests following fire, painting, or chemical release in areas communicating with the affected system. To conservatively implement this requirement, many plants categorize welding as a chemical release process, and institute controls to ensure that welding fumes do not interact with carbon adsorbers in a filter system. After reviewing research data that indicated welding had a minimal impact on adsorber iodine removal efficiency, further testing was performed with the goal of establishing a welding threshold. It was anticipated that some quantity of weld electrodes could be determined that had a corresponding detrimental impact on iodine removal efficiency for the exposed adsorber. This value could be used to determine a conservative sampling schedule that would allow the station to perform laboratory testing to ensure system degradation did not occur without a full battery of surveillance tests. A series of tests was designed to demonstrate carbon efficiency versus cumulative welding fume exposure. Three series of tests were performed, one for each of three different types of commonly used weld electrodes. Carbon sampling was performed at baseline conditions, and every five pounds of electrode thereafter. Two different laboratory tests were performed for each sample; one in accordance with ASTM 3803/1989 at 95% relative humidity and 30 degrees C, and another using the less rigorous conditions of 70% relative humidity and 80 degrees C. Review of the test data for all three types of electrodes failed to show a significant correlation between carbon efficiency degradation and welding fume exposure. Accordingly, welding is no longer categorized as a `chemical release process` at McGuire Nuclear Station, and limits on welding fume interaction with ventilation systems have been eliminated. 4 refs., 3 figs., 1 tab.

  5. Contamination and solid state welds.

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Bernice E.

    2007-05-01

    Since sensitivity to contamination is one of the verities of solid state joining, there is a need for assessing contamination of the part(s) to be joined, preferably nondestructively while it can be remedied. As the surfaces that are joined in pinch welds are inaccessible and thus provide a greater challenge, most of the discussion is of the search for the origin and effect of contamination on pinch welding and ways to detect and mitigate it. An example of contamination and the investigation and remediation of such a system is presented. Suggestions are made for techniques for nondestructive evaluation of contamination of surfaces for other solid state welds as well as for pinch welds. Surfaces that have good visual access are amenable to inspection by diffuse reflection infrared Fourier transform (DRIFT) spectroscopy. Although other techniques are useful for specific classes of contaminants (such as hydrocarbons), DRIFT can be used most classes of contaminants. Surfaces such as the interior of open tubes or stems that are to be pinch welded can be inspected using infrared reflection spectroscopy. It must be demonstrated whether or not this tool can detect graphite based contamination, which has been seen in stems. For tubes with one closed end, the technique that should be investigated is emission infrared spectroscopy.

  6. Laser welding of selected aerospace alloys

    Science.gov (United States)

    Ebadan, Gracie E.

    The study was aimed at developing an understanding of the microstructural effects of the laser welding process on the alloys, and assessing the structural integrity of the resultant welds. The effect of laser processing parameters such as laser power, laser beam traverse speed, lens focal length, and the manipulation of these parameters on the welding efficiency and weld area integrity was also investigated. Other tasks within the project included a study on the possibility of using an anodic film to enhance the laser weld ability of Al 6061. Finally, attempts were made to identify phases observed in the weld area of the composite materials. Nimonics C263 and PE11 exhibited laser welds free of cracks and porosity. The difference in composition between the two alloys did not result in any significant dissimilarities in their response to the laser welding process. The welds in both alloys exhibited a fine columnar dendritic microstructure, and while carbides were observed in the interdendritic regions of the welds, electron optical analysis did not reveal any gamma' precipitates in this region. It was concluded that for the welding of thin gage materials above a threshold laser power the resultant welding efficiency shows a greater dependence on laser beam mode, and laser spot size, than on laser power, and beam traverse speed. Aluminum 6061 was not easily welded with a laser in its as received form, and the welds showed some degree of porosity. Anodizing was found to improve the welding efficiency in this material. While the presence of an anodic film on the metal surface increased the welding efficiency of the alloy, no relationship was found between the thickness of the anodic film and welding efficiency in the range of film thicknesses investigated. Weld regions were observed to be cellular dendritic in structure, with narrow heat affected zones. No precipitates or low melting point phases could be identified in the weld region. Melt zones were successfully

  7. Analysis and Comparison of Aluminum Alloy Welded Joints Between Metal Inert Gas Welding and Tungsten Inert Gas Welding

    Science.gov (United States)

    Zhao, Lei; Guan, Yingchun; Wang, Qiang; Cong, Baoqiang; Qi, Bojin

    2015-09-01

    Surface contamination usually occurs during welding processing and it affects the welds quality largely. However, the formation of such contaminants has seldom been studied. Effort was made to study the contaminants caused by metal inert gas (MIG) welding and tungsten inert gas (TIG) welding processes of aluminum alloy, respectively. SEM, FTIR and XPS analysis was carried out to investigate the microstructure as well as surface chemistry. These contaminants were found to be mainly consisting of Al2O3, MgO, carbide and chromium complexes. The difference of contaminants between MIG and TIG welds was further examined. In addition, method to minimize these contaminants was proposed.

  8. Electron Beam Welding to Join Gamma Titanium Aluminide Articles

    Science.gov (United States)

    Kelly, Thomas Joseph (Inventor)

    2008-01-01

    A method is provided for welding two gamma titanium aluminide articles together. The method includes preheating the two articles to a welding temperature of from about 1700 F to about 2100 F, thereafter electron beam welding the two articles together at the welding temperature and in a welding vacuum to form a welded structure, and thereafter annealing the welded structure at an annealing temperature of from about 1800 F to about 2200 F, to form a joined structure.

  9. 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.

  10. Upgrading weld quality of a friction stir welded aluminum alloys AMG6

    Science.gov (United States)

    Chernykh, I. K.; Vasil’ev, E. V.; Matuzko, E. N.; Krivonos, E. V.

    2018-01-01

    In the course of introduction of FSW technology into the industry there is a keen interest in this process; there are issues such as how does joining take place, what is the structure of the joint, and where there are dangerous zones. The objective of this research is to obtain information about the structure of the joint, what are the temperatures that arise during the joining, what strength is apply to the tool when joining the material, what tensile strength of joint, and where fracture tended to occur. Specimens were produced at different modes of welding at a tool rotation speed of 315 to 625 rpm and tool travel speed of 40 to 125 mm/min. During the experiment, the strength applied to the tool was measured, which reached 800016000 N (Fz) and 400-1400 N (Fx) and the temperature on the surface of the tool, which is in the range 250-400°C. Before the welding process the tool was heated to a temperature in the range of 100-250 degrees, but the tensile strength is not had a tangible impact. The tensile strength is about 80 % of that of the aluminum alloy base metal tensile strength, and fracture tended is occur not at the line of joint but follow the shape of the tool. In the transverse cross section of a FSW material there is a microstructural regions such as weld nugget, thermomechanically affected zone and heat-affected zone with parent material.

  11. Advanced Welding Tool

    Science.gov (United States)

    1982-01-01

    Accutron Tool & Instrument Co.'s welder was originally developed as a tool specifically for joining parts made of plastic or composite materials in any atmosphere to include the airless environment of space. Developers decided on induction or magnetic heating to avoid causing deformation and it also can be used with almost any type of thermoplastic material. Induction coil transfers magnetic flux through the plastic to a metal screen that is sandwiched between the sheets of plastic to be joined. When welder is energized, alternating current produces inductive heating on the screen causing the adjacent plastic surfaces to melt and flow into the mesh, creating a bond on the total surface area. Dave Brown, owner of Great Falls Canoe and Kayak Repair, Vienna, VA, uses a special repair technique based on operation of the Induction Toroid Welder to fix canoes. Whitewater canoeing poses the problem of frequent gashes that are difficult to repair. The main reason is that many canoes are made of plastics. The commercial Induction model is a self-contained, portable welding gun with a switch on the handle to regulate the temperature of the plastic melting screen. Welder has a broad range of applications in the automobile, appliance, aerospace and construction industries.

  12. Effect of weld spacing on microstructure and mechanical properties of CLAM electron beam welding joints

    Energy Technology Data Exchange (ETDEWEB)

    Zhai, Yutao; Huang, Bo, E-mail: aufa0007@163.com; Zhang, Junyu; Zhang, Baoren; Liu, Shaojun; Huang, Qunying

    2016-11-15

    Highlights: • The welded joints of CLAM steel with different weld spacings have been fabricated with electron beam welding, and a simplified model of CLAM sheet was proposed. • The microstructure and mechanical properties such as microhardness, impact and tensile were investigated at different welding spacing for both conditions of as-welded and post weld heat treatment (PWHT). • The effect of the welding thermal cycle was significantly when the weld spacings were smaller than 4 mm. • When the weld spacing was small enough, the original microstructures would be fragmented with the high heat input. - Abstract: China low activation martensitic (CLAM) steel has been chosen as the primary structural material in the designs of dual function lithium-lead (DFLL) blanket for fusion reactors, China helium cooled ceramic breeder (HCCB) test blanket module (TBM) for ITER and China fusion engineering test reactor (CFETR) blanket. The cooling components of the blankets are designed with high density cooling channels (HDCCs) to remove the high nuclear thermal effectively. Hence, the welding spacing among the channels are small. In this paper, the welded joints of CLAM steel with different weld spacings have been fabricated with electron beam welding (EBW). The weld spacing was designed to be 2 mm, 3 mm, 4 mm, 6 mm and 8 mm. The microstructure and mechanical properties such as microhardness, impact and tensile were investigated at different welding spacing for both conditions of as-welded and post weld heat treatment (PWHT). The PWHT is tempering at 740 °C for 120 min. The results showed that the grain size in the heat affected zone (HAZ) increased with the increasing weld spacing, and the joint with small weld spacing had a better performance after PWHT. This work would give useful guidance to improve the preparation of the cooling components of blanket.

  13. Analysis of the bonding strength and microstructure of AA6082 extrusion weld seams formed during physical simulation

    NARCIS (Netherlands)

    Bai, Sheng Wen; Fang, Gang; Zhou, J.

    2017-01-01

    The research was aimed to determine the effects of extrusion process condition on the weld seam quality of the aluminum alloy AA6082 by using a novel physical simulation method. A weld seam between two bars was formed under hydrostatic pressure in a specially designed die setup to simulate the

  14. 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.

  15. Metal vaporization from weld pools

    Science.gov (United States)

    Block-Bolten, A.; Eagar, T. W.

    1984-09-01

    Experimental studies of alloy vaporization from aluminum and stainless steel weld pools have been made in order to test a vaporization model based on thermodynamic data and the kinetic theory of gases. It is shown that the model can correctly predict the dominant metal vapors that form but that the absolute rate of vaporization is not known due to insufficient knowledge of the surface temperature distribution and subsequent condensation of the vapor in the cooler regions of the metal. Values of the net evaporation rates for different alloys have been measured and are found to vary by two orders of magnitude. Estimated maximum weld pool temperatures based upon the model are in good agreement with previous experimental measurements of electron beam welds.

  16. STUDY AND ANALYSIS OF THE EFFECT OF WELDING PROCESS ON DISTORTION WITH 304L STAINLESS STEEL WELD JOINTS

    OpenAIRE

    Dhananjay Kumar*, Dharamvir mangal

    2017-01-01

    The effect of welding process on the distortion with 304L stainless steel 12thk weld joints made by TIG (tungsten inert gas) and SMAW (Shielded metal arc welding) welding process involving different type joint configuration have been studied. The joint configurations employed were double V-groove edge preparation for double side SMAW welding and square – butt preparation for double side TIG welding. All weld joints passed by radiographic. Distortion measurements were carried out using height ...

  17. The Effect of Vibration during Friction Stir Welding on Corrosion Behavior, Mechanical Properties, and Machining Characteristics of Stir Zone

    Directory of Open Access Journals (Sweden)

    Sajad Fouladi

    2017-10-01

    Full Text Available Different methods have been applied to refine various characteristics of the zone (or nugget obtained by friction stir welding (FSW. In the current research, joining components are vibrated normal to the weld line during FSW to refine the zone microstructure. This process is described as friction stir vibration welding (FSVW. The effect of FSVW on mechanical properties, corrosion behavior, and machining characteristics of the zone are investigated. Al5052 alloy specimens are welded using FSW and FSVW processes and their different characteristics are compared and discussed. The results show that the strength and ductility of the welded parts increase when the vibration is applied. The outcomes also show that corrosion resistance of the nugget for FSV-welded specimens is lower than FS welded samples, and machining force of the former specimens is higher than the latter ones. These are related to smaller grain size in the zone of FSV-welded specimens compared to FS welded parts. Smaller grain size leads to a greater volume fraction of grain boundaries and, correspondingly, higher strength and hardness, as well as lower corrosion resistance.

  18. Laser Beam Submerged Arc Hybrid Welding

    Science.gov (United States)

    Reisgen, Uwe; Olschok, Simon; Jakobs, Stefan; Schleser, Markus; Mokrov, Oleg; Rossiter, Eduardo

    The laser beam-submerged arc hybrid welding method originates from the knowledge that, with increasing penetration depth, the laser beam process has a tendency to pore formation in the lower weld regions. The coupling with the energy-efficient submerged-arc process improves degassing and reduces the tendency to pore formation. The high deposition rate of the SA process in combination with the laser beam process offers, providing the appropriate choice of weld preparation, the possibility of welding plates with a thickness larger than 20° mm in a single pass, and also of welding thicker plates with the double-sided single pass technique.

  19. Peculiarities and future development of space welding

    Science.gov (United States)

    Shulym, V. F.; Lapchinskii, V. F.; Nikitskii, V. P.; Demidov, D. L.; Neznamova, L. O.

    The paper deals with the peculiar features of space as a medium in which welding operations are performed. Studies of different methods of welding carried out both in the plane-laboratory and in space are briefly described, and the comparative characteristics of the most promising methods of welding for space conditions are given. The selection of electron beam as a basic method for space is supported. The paper considers the main welding processes performed in space with the help of an electron beam, such as heating, brazing, welding, cutting and coating.

  20. Grain refinement control in TIG arc welding

    Science.gov (United States)

    Iceland, W. F.; Whiffen, E. L. (Inventor)

    1975-01-01

    A method for controlling grain size and weld puddle agitation in a tungsten electrode inert gas welding system to produce fine, even grain size and distribution is disclosed. In the method the frequency of dc welding voltage pulses supplied to the welding electrode is varied over a preselected frequency range and the arc gas voltage is monitored. At some frequency in the preselected range the arc gas voltage will pass through a maximum. By maintaining the operating frequency of the system at this value, maximum weld puddle agitation and fine grain structure are produced.

  1. Fatigue of weld ends under combined in- and out-of-phase multiaxial loading

    Directory of Open Access Journals (Sweden)

    E. Shams

    2016-10-01

    Full Text Available Weld start and end points are fatigue failure sensitive locations. Their fatigue behaviour especially in thin sheet structures under multiaxial load conditions is not sufficiently explored so far. Therefore, a research project was initiated to increase the knowledge concerning this topic, which is of special interest in the automotive industry. In the present study, fatigue tests on welded joints were conducted. In the numerical part of the study, notch stresses were calculated with an idealised weld end model. A numerical method which combines the geometrical and statistical size effect to an integrated approach was used, in order to consider the size effects

  2. Structural Phase Evolution in Ultrasonic-Assisted Friction Stir Welded 2195 Aluminum Alloy Joints

    Science.gov (United States)

    Eliseev, A. A.; Fortuna, S. V.; Kalashnikova, T. A.; Chumaevskii, A. V.; Kolubaev, E. A.

    2017-10-01

    The authors examined the structural and phase state of fixed joints produced by method of friction stir welding (FSW) and ultrasonic-assisted friction stir welding (UAFSW) from extruded profile of aluminum alloy AA2195. In order to identify the role of ultrasonic application in the course of welding, such characteristics, as volume fraction and average size of secondary particles are compared in the base material and stir zones of FSW and UAFSW joints. By applying the methods of SEM and TEM analysis, researchers established the complex character of phase transitions as a result of ultrasonic application.

  3. Advantages of new micro-jet welding technology on weld microstructure control

    Directory of Open Access Journals (Sweden)

    Jan PIWNIK

    2013-01-01

    Full Text Available An innovative apparatus to welding process with micro-jet cooling of the weld made it possible to carry out technological tests, which have proved theoretical considerations about this problem. This project gives real opportunities for professional development in the field of welding with controlling the parameters of weld structure. These tests have proved that the new micro-jet technology has the potential for growth. It may be great achievement of welding technology in order to increase weld metal strength. The new technology with micro-jet cooling may have many practical applications in many fields, for example such as in the transport industry or to repair damaged metal elements. The advantages of the new device over the traditional system are the ability to control the structure of the weld, the weld mechanical performance increases and improve the quality of welded joints.

  4. Experimental Study of the Redistribution of Welding Distortion According to the Partial Removal of Welded Structure

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Yong Rae; Wang, Chao; Kim, Jae Woong [Yeungnam University, Kyungsan (Korea, Republic of)

    2015-07-15

    During the welding process, welding distortion is caused by the non-uniformity of the temperature distribution in the weldment. Welding distortion is redistributed because the residual stress and rigidity change according to the removal of the welded structure. In shipbuilding in particular, this phenomenon may be observed during the cutting process of lugs that are attached to blocks for transfer. The redistribution of welding distortion also causes problems, such as damage to the cutting tool. The aim of this study is to experimentally analyze the redistribution of welding distortion because of the partial removal of the welded structure. In the experiments conducted in this study, fillet welding and cutting were performed, and longitudinal bending and angular distortion in the welded structures were then investigated and analyzed.

  5. Experimental investigation on the weld pool formation process in plasma keyhole arc welding

    Science.gov (United States)

    Van Anh, Nguyen; Tashiro, Shinichi; Van Hanh, Bui; Tanaka, Manabu

    2018-01-01

    This paper seeks to clarify the weld pool formation process in plasma keyhole arc welding (PKAW). We adopted, for the first time, the measurement of the 3D convection inside the weld pool in PKAW by stereo synchronous imaging of tungsten tracer particles using two sets of x-ray transmission systems. The 2D convection on the weld pool surface was also measured using zirconia tracer particles. Through these measurements, the convection in a wide range of weld pools from the vicinity of the keyhole to the rear region was successfully visualized. In order to discuss the heat transport process in a weld pool, the 2D temperature distribution on the weld pool surface was also measured by two-color pyrometry. The results of the comprehensive experimental measurement indicate that the shear force due to plasma flow is found to be the dominant driving force in the weld pool formation process in PKAW. Thus, heat transport in a weld pool is considered to be governed by two large convective patterns near the keyhole: (1) eddy pairs on the surface (perpendicular to the torch axis), and (2) eddy pairs on the bulk of the weld pool (on the plane of the torch). They are formed with an equal velocity of approximately 0.35 m s‑1 and are mainly driven by shear force. Furthermore, the flow velocity of the weld pool convection becomes considerably higher than that of other welding processes, such as TIG welding and GMA welding, due to larger plasma flow velocity.

  6. Residual stress characterization of welds and post-weld processes using x-ray diffraction techniques

    Science.gov (United States)

    Brauss, Michael E.; Pineault, James A.; Eckersley, John S.

    1998-03-01

    This paper illustrates the importance of residual stress characterization in welds and post weld processes. The failure to characterize residual stresses created during welding and/or post weld processes can lead to unexpected occurrences of stress corrosion cracking, distortion, fatigue cracking as well as instances of over design or over processing. The development of automated residual stress mapping and the availability of portable and fast equipment have now made the characterization of residual stresses using x-ray diffraction practical for process control and optimization. The paper presents examples where x-ray diffraction residual stress characterization techniques were applied on various kinds of welds including arc welds, TIG welds, resistance welds, laser welds and electron beam welds. The nondestructive nature of the x-ray diffraction technique has made the residual stress characterization of welds a useful tool for process optimization and failure analysis, particularly since components can be measured before and after welding and post welding processes. Some examples presented show the residual stresses before and after the application of post weld processes such as shot peening, grinding and heat treatment.

  7. Shimmed electron beam welding process

    Science.gov (United States)

    Feng, Ganjiang; Nowak, Daniel Anthony; Murphy, John Thomas

    2002-01-01

    A modified electron beam welding process effects welding of joints between superalloy materials by inserting a weldable shim in the joint and heating the superalloy materials with an electron beam. The process insures a full penetration of joints with a consistent percentage of filler material and thereby improves fatigue life of the joint by three to four times as compared with the prior art. The process also allows variable shim thickness and joint fit-up gaps to provide increased flexibility for manufacturing when joining complex airfoil structures and the like.

  8. TIG welding power supply with improved efficiency

    Directory of Open Access Journals (Sweden)

    Сергій Володимирович Гулаков

    2015-03-01

    Full Text Available In the article, the influence of the DC component of the welding current during TIG (Tungsten Inert Gas welding is discussed. Known methods of DC current cancellation are reviewed, such as capacitor bank or diode/thyristor network insertion in the secondary circuit of the welding transformer. A new method of controlling the magnitude and shape of the TIG welding current is proposed. The idea is to insert a controlled voltage source in the secondary circuit of the welding transformer. This controlled voltage source is realized using a full-bridge voltage source inverter (VSI. VSI control system design issues are discussed. VSI is controlled by a three-level hysteretic current controller, while current reference is generated using lookup table driven by PLL (Phase Locked Loop locked to the mains frequency. Simulation results are shown. The proposed topology of TIG power supply allows to provide magnitude and shape control of the welding current, with the limitation that its DC component must be zero. Thus, some capabilities of professional AC-TIG welders are obtained using substantially lower cost components: VSI built using high-current low voltage MOSFETs with control system based on 32-bit ARM microcontroller. The use of proposed TIG welding power supply will eliminate the DC component of the welding current, improve welding transformer’s power factor and improve welding technology by increasing the welding arc stability

  9. Experimental analysis of cut welding in aluminium

    DEFF Research Database (Denmark)

    Dorph, Pernille; De Chiffre, Leonardo; Bay, Niels

    1993-01-01

    Cut welding is a newly developed cold pressure welding process. In the present work, an experimental investigation was carried out analyzing the mechanisms involved in cut welding of a block to a strip. Experiments were carried out in technically pure aluminium. The investigation has involved...... tensile testing and metallographic investigations of the welds. The results show that this variant of cut welding is a very reproducible process giving a weld strength equal to 30-40% the strength of the parent material. The experiments have shown that the reason for this relatively low strength...... is an uneven pressure distribution along the weld due to a wave formed during sliding. Attempts to alter the material flow during sliding are presented....

  10. Welding of gamma titanium aluminide alloys

    Science.gov (United States)

    Smashey, Russell W. (Inventor); Kelly, Thomas J. (Inventor); Snyder, John H. (Inventor); Sheranko, Ronald L. (Inventor)

    1998-01-01

    An article made of a gamma titanium aluminide alloy is welded, as for example in the weld repair of surface cracks, by removing foreign matter from the area to be welded, first stress relieving the article, cooling the entire article to a welding temperature of from about 1000.degree. F. to about 1400.degree. F., welding a preselected region in an inert atmosphere at the welding temperature, and second stress relieving the article. Welding is preferably accomplished by striking an arc in the preselected region so as to locally melt the alloy in the preselected region, providing a filler metal having the same composition as the gamma titanium aluminide alloy of the article, and feeding the filler metal into the arc so that the filler metal is melted and fused with the article to form a weldment upon solidification.

  11. Numerical Simulation of Duplex Steel Multipass Welding

    Directory of Open Access Journals (Sweden)

    Giętka T.

    2016-12-01

    Full Text Available Analyses based on FEM calculations have significantly changed the possibilities of determining welding strains and stresses at early stages of product design and welding technology development. Such an approach to design enables obtaining significant savings in production preparation and post-weld deformation corrections and is also important for utility properties of welded joints obtained. As a result, it is possible to make changes to a simulated process before introducing them into real production as well as to test various variants of a given solution. Numerical simulations require the combination of problems of thermal, mechanical and metallurgical analysis. The study presented involved the SYSWELD software-based analysis of GMA welded multipass butt joints made of duplex steel sheets. The analysis of the distribution of stresses and displacements were carried out for typical welding procedure as during real welding tests.

  12. Residual stress simulation of circumferential welded joints

    Directory of Open Access Journals (Sweden)

    Melicher R.

    2007-11-01

    Full Text Available Residual stresses are an important consideration in the component integrity and life assessment of welded structure. The welding process is very complex time dependent physical phenomenon with material nonlinearity. The welding is a thermal process with convection between fluid flow and welding body, between welding bodyand environment. Next type of boundary conditions is radiation and thermo-mechanical contact on the outer surface of gas pipe in the near of weld. The temperature variation so obtained is utilised to find the distribution of the stress field.In this paper, a brief review of weld simulation and residual stress modelling using the finite element method (FEM by commercial software ANSYS is presented. Thermo-elastic-plastic formulations using a von Mises yield criterion with nonlinear kinematics hardening has been employed. Residual axial and hoop stresses obtained from the analysis have been shown. The commercial FEM code ANSYS was used for coupled thermalmechanical analysis.

  13. Yield load solutions of heterogeneous welded joints

    Energy Technology Data Exchange (ETDEWEB)

    Kozak, D., E-mail: dkozak@sfsb.h [Mechanical Engineering Faculty in Slavonski Brod, Josip Juraj Strossmayer University of Osijek, Trg Ivane Brlic-Mazuranic 2, Hr-35000 Slavonski Brod (Croatia); Gubeljak, N. [Faculty of Mechanical Engineering, University of Maribor, Smetanova 17, SI-2000 Maribor (Slovenia); Konjatic, P.; Sertic, J. [Mechanical Engineering Faculty in Slavonski Brod, Josip Juraj Strossmayer University of Osijek, Trg Ivane Brlic-Mazuranic 2, Hr-35000 Slavonski Brod (Croatia)

    2009-12-15

    The aim of this paper is to establish yield load solutions when the materials inhomogeneity within the weld is present, which is usually the case in repair welding. The effect of yield strength mismatch of welded joints performed with different geometry on the yield load value has been investigated in the context of single edge notched fracture toughness specimen subjected to bending SE(B) using the finite element method. The crack was located in the center of the weld and the two most important geometrical parameters were identified as: crack length ratio a/W as well as slenderness of the welded joint, which were systematically varied. One practical and four additional combinations of filler materials, with the same portion of overmatched part and undermatched part of the weld, were analyzed, and plane strain FE solutions for the case when the crack is located in the overmatched half of the heterogeneous weld were obtained.

  14. Influence of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel welding joints

    Science.gov (United States)

    Zhang, Zhiqiang; Jing, Hongyang; Xu, Lianyong; Han, Yongdian; Zhao, Lei; Zhang, Jianli

    2017-02-01

    The influences of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel joints welded by gas tungsten arc welding (GTAW) and flux-cored arc welding (FCAW) with different shielding gas compositions were studied by optical microscopy, electron backscatter diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, electron probe microanalysis, and potentiostatic and potentiodynamic polarization methods The adding 2% N2 in shielding gas facilitated primary austenite formation in GTAW weld metal (WM) and suppressed Cr2N precipitation in GTAW weld root. In the HAZ, the banded microstructure disappeared while the coarse ferrite grains maintained same orientation as the banded ferrite in the BM. In the WM, the ferrite had one single orientation throughout a grain, whereas several families of austenite appeared. The austenite both in BM and WM enriched in Ni and nitro`gen, while Cr and Mo were concentrated in the ferrite and thus no element showed clear dendritic distribution in the WM (ER2209 and E2209T1). In addition, the secondary austenite had higher Ni content but lower Cr and Mo content than the primary austenite. The N2-supplemented shielding gas promoted nitrogen solid-solution in the primary and secondary austenite. Furthermore, the secondary austenite had relatively lower pitting resistance equivalent number (PREN) than the ferrite and primary austenite, thereby resulting in its preferential corrosion. The Cr2N precipitation led to relatively poor resistance to pitting corrosion in three HAZs and pure Ar shielding GTAW weld root. The N2-supplemented shielding gas improved pitting corrosion resistance of GTAW joint by increasing PREN of secondary austenite and suppressing Cr2N precipitation. In addition, the FCAW WM had much poorer resistance to pitting corrosion than the GTAW WM due to many O-Ti-Si-Mn inclusions. In the BM, since the austenite with lower PREN compared

  15. Mechanical Properties of Plug Welds after Micro-Jet Cooling

    Directory of Open Access Journals (Sweden)

    Hadryś D.

    2016-12-01

    Full Text Available New technology of micro-jet welding could be regarded as a new way to improve mechanical properties of plug welds. The main purpose of that paper was analyzing of mechanical properties of plug welds made by MIG welding method with micro-jet cooling. The main way for it was comparison of plug welds made by MIG welding method with micro-jet cooling and plug welds made by ordinary MIG welding method. It is interesting for steel because higher amount of acicular ferrite (AF in weld metal deposit (WMD is obtained in MIG welding method with micro-jet cooling in relation to ordinary MIG welding method. This article presents the influence of the cooling medium and the number of micro-jet streams on mechanical properties of the welded joint. Mechanical properties were described by force which is necessary to destroy weld joint.

  16. A Brief Introduction to the Theory of Friction Stir Welding

    Science.gov (United States)

    Nunes, Arthur C., Jr.

    2008-01-01

    Friction stir welding (FSW) is a solid state welding process invented in 1991 at The Welding Institute in the United Kingdom. A weld is made in the FSW process by translating a rotating pin along a weld seam so as to stir the sides of the seam together. FSW avoids deleterious effects inherent in melting and is already an important welding process for the aerospace industry, where welds of optimal quality are demanded. The structure of welds determines weld properties. The structure of friction stir welds is determined by the flow field in the weld metal in the vicinity of the weld tool. A simple kinematic model of the FSW flow field developed at Marshall Space Flight Center, which enables the basic features of FSW microstructure to be understood and related to weld process parameters and tool design, is explained.

  17. Mechanical Properties of Plug Welds after Micro-Jet Cooling

    OpenAIRE

    Hadryś D.

    2016-01-01

    New technology of micro-jet welding could be regarded as a new way to improve mechanical properties of plug welds. The main purpose of that paper was analyzing of mechanical properties of plug welds made by MIG welding method with micro-jet cooling. The main way for it was comparison of plug welds made by MIG welding method with micro-jet cooling and plug welds made by ordinary MIG welding method. It is interesting for steel because higher amount of acicular ferrite (AF) in weld metal deposit...

  18. 49 CFR 192.235 - Preparation for welding.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Preparation for welding. 192.235 Section 192.235... BY PIPELINE: MINIMUM FEDERAL SAFETY STANDARDS Welding of Steel in Pipelines § 192.235 Preparation for welding. Before beginning any welding, the welding surfaces must be clean and free of any material that...

  19. 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 in...

  20. Mathematical Model Of Variable-Polarity Plasma Arc Welding

    Science.gov (United States)

    Hung, R. J.

    1996-01-01

    Mathematical model of variable-polarity plasma arc (VPPA) welding process developed for use in predicting characteristics of welds and thus serves as guide for selection of process parameters. Parameters include welding electric currents in, and durations of, straight and reverse polarities; rates of flow of plasma and shielding gases; and sizes and relative positions of welding electrode, welding orifice, and workpiece.

  1. Nutritional supplements

    DEFF Research Database (Denmark)

    Petersen, Gry Bjerg; Andersen, Jens Rikardt

    2015-01-01

    Background: Several studies have indicated that cancer patients have significantly altered taste sensitivity without specifying the preferences. One of the related problems is low compliance to nutritional therapy with oral nutritional supplements (ONS) in patients suffering severe weight loss...

  2. Supplemental information

    Data.gov (United States)

    U.S. Environmental Protection Agency — Supplemental information showing results of inter-comparison between C-PORT, AERMOD and R-LINE dispersion algorithms. This dataset is associated with the following...

  3. Analysis of factors affecting fractures of rails welded by alumino-thermic welding

    OpenAIRE

    Sergejs MIKHAYLOVS; Dijs SERGEJEVS

    2008-01-01

    On Latvian Railway, the use of the thermic welding is widespread using the ELECTRO-THERMIT Company technology. Today it is a basic method for rail joints. Experience of the operation of rails welded by the thermic welding showed that every year occur from 2 to 3 fractures of thermic joints on the main tracks between stations of Latvian Railway.Such emergence of cracks in the weld joint alongside the scores indicates of great residual stresses in the weld joints made by the thermic welding.

  4. Nitrogen And Oxygen Amount In Weld After Welding With Micro-Jet Cooling

    OpenAIRE

    Węgrzyn T.; Piwnik J.

    2015-01-01

    Micro-jet cooling after welding was tested only for MIG welding process with argon, helium and nitrogen as a shielded gases. A paper presents a piece of information about nitrogen and oxygen in weld after micro-jet cooling. There are put down information about gases that could be chosen both for MIG/MAG welding and for micro-jet process. There were given main information about influence of various micro-jet gases on metallographic structure of steel welds. Mechanical properties of weld was pr...

  5. Resistance spot welding of galvanized steel: Part II. Mechanisms of spot weld nugget formation

    Science.gov (United States)

    Gedeon, S. A.; Eagar, T. W.

    1986-12-01

    Dynamic inspection monitoring of the weld current, voltage, resistance, electrode displacement, and force was performed in conjunction with a detailed study of the effects of material variations and weld process parameter modifications on resistance spot welding of coated and uncoated steels. In order to determine the mechanisms of weld nugget formation and growth, scanning electron microscopy photos were taken of the developing nugget. These physical changes were then related to the dynamic inspection curves and the welding current lobe. The effects of material variations and weld process modifications, the results of which were presented in Part I, can be explained through an understanding of these mechanisms.

  6. Experimental studies of parameters affecting the heat generation in friction stir welding process

    Directory of Open Access Journals (Sweden)

    Mijajlović Miroslav M.

    2012-01-01

    Full Text Available Heat generation is a complex process of transformation of a specific type of energy into heat. During friction stir welding, one part of mechanical energy delivered to the welding tool is consumed in the welding process, another is used for deformational processes etc., and the rest of the energy is transformed into heat. The analytical procedure for the estimation of heat generated during friction stir welding is very complex because it includes a significant number of variables and parameters, and many of them cannot be fully mathematically explained. Because of that, the analytical model for the estimation of heat generated during friction stir welding defines variables and parameters that dominantly affect heat generation. These parameters are numerous and some of them, e. g. loads, friction coefficient, torque, temperature, are estimated experimentally. Due to the complex geometry of the friction stir welding process and requirements of the measuring equipment, adequate measuring configurations and specific constructional solutions that provide adequate measuring positions are necessary. This paper gives an overview of the process of heat generation during friction stir welding, the most influencing parameters on heat generation, constructional solutions for the measuring equipment needed for these experimental researches and examples of measured values.

  7. INVESTIGATION OF SINGLE-PASS/DOUBLE-PASS TECHNIQUES ON FRICTION STIR WELDING OF ALUMINIUM

    Directory of Open Access Journals (Sweden)

    N.A.A. Sathari

    2014-12-01

    Full Text Available The aim of this research is to study the effects of single-pass/ double-pass techniques on friction stir welding of aluminium. Two pieces of AA1100 with a thickness of 6.0 mm were friction stir welded using a CNC milling machine at rotational speeds of 1400 rpm, 1600 rpm and 1800 rpm respectively for single-pass and double-pass. Microstructure observations of the welded area were studied using an optical microscope. The specimens were tested by using a tensile test and Vickers hardness test to evaluate their mechanical properties. The results indicated that, at low rotational speed, defects such as ‘surface lack of fill’ and tunnels in the welded area contributed to a decrease in mechanical properties. Welded specimens using double-pass techniques show increasing values of tensile strength and hardness. From this investigation it is found that the best parameters of FSW welded aluminium AA1100 plate were those using double-pass techniques that produce mechanically sound joints with a hardness of 56.38 HV and 108 MPa strength at 1800 rpm compared to the single-pass technique. Friction stir welding, single-pass/ double-pass techniques, AA1100, microstructure, mechanical properties.

  8. A review of micro/nano welding and its future developments.

    Science.gov (United States)

    Guo, Kelvii W

    2009-01-01

    A review is given about the current state-of-the-art surrounding micro/nano scale welding/joining used in miniaturization or microsystems. Except for reviewing the applications of micro/nano welding/joining in various fields, such as microelectromechanical system (MEMS), micro total-analysis systems (microTAS), carbon nanotubes (CNTs) etc., the optimal equipments for micro/nano welding/joining, its corresponding future applications and research directions are discussed. Moreover, an extensive part of the paper is devoted to the introduction of new techniques, micro/nano laser and electron beam welding/joining. In turn, it is anticipated these techniques will be used in future micro/nano welding/joining applications. Meanwhile, because even smallest particles of dust can influence the results, more considerations are given to machine improvements that are required for its corresponding nano welding/joining. It will be one challenge for R&D efforts to combine the progress in micro/nano scales with that in miniaturization. This review provides a timely explanation of the literature surrounding the factors required for successful micro and nano welding/joining.

  9. 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.

  10. Twin-spot laser welding of advanced high-strength multiphase microstructure steel

    Science.gov (United States)

    Grajcar, Adam; Morawiec, Mateusz; Różański, Maciej; Stano, Sebastian

    2017-07-01

    The study addresses the results concerning the laser welding of TRIP (TRansformation Induced Plasticity) steel using a beam focused at two spots (also referred to as twin-spot laser welding). The analysis involved the effect of variable welding thermal cycles on the properties and microstructure of welded joints. The tests were performed using a linear energy of 0.048 and 0.060 kJ/mm and the laser beam power distribution of 50%:50%, 60%:40% and 70%:30%. The tests also involved welding performed using a linear energy of 0.150 kJ/mm and the laser beam power distribution of 70%:30%. In addition, the research included observations of the microstructure of the fusion zone, heat affected zone and the transition zone using light microscopy and scanning electron microscopy. The fusion zone was composed of blocky-lath martensite whereas the HAZ (heat-affected zone) was characterised by the lath microstructure containing martensite, bainite and retained austenite. The distribution of twin-spot laser beam power significantly affected the microstructure and hardness profiles of welded joints. The highest hardness (480-505 HV), regardless of welding variants used, was observed in the HAZ.

  11. Brittle crack arrestability of thick steel plate welds in large structure

    Science.gov (United States)

    An, Gyu Baek; Park, Joon Sik

    2011-10-01

    Recently, there has been such a critical issue in shipbuilding industry that much larger and stronger ships are required to develop oil and gas in the Arctic region. Attention has been paid to obtaining high strength, good toughness at low temperature, and good weldability. An experimental study was performed to evaluate the brittle crack arrest toughness value (Kca) and brittle crack arrest method of welded joints using EH40 grade steel with a thickness of 80 mm. The test specimens were made by both flux cored arc welding (FCAW) and combined welding (EGW+FCAW) processes. Temperature gradient ESSO test was performed to measure the Kca of the base metal. Also, a constant temperature (-10 °C) ESSO test was performed to establish a brittle crack arrest method using high toughness welding consumable with real structural specimens. The research aims in this study were to investigate the effect of joint design and welding consumable for the crack arrestability of thick steel plates using EH40 grade shipbuilding steel of straight block joint weld line with two kinds of welding processes.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-03-31

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

  13. Mechanics Model of Plug Welding

    Science.gov (United States)

    Zuo, Q. K.; Nunes, A. C., Jr.

    2015-01-01

    An analytical model has been developed for the mechanics of friction plug welding. The model accounts for coupling of plastic deformation (material flow) and thermal response (plastic heating). The model predictions of the torque, energy, and pull force on the plug were compared to the data of a recent experiment, and the agreements between predictions and data are encouraging.

  14. Fundamentals of Welding. Teacher Edition.

    Science.gov (United States)

    Fortney, Clarence; And Others

    These instructional materials assist teachers in improving instruction on the fundamentals of welding. The following introductory information is included: use of this publication; competency profile; instructional/task analysis; related academic and workplace skills list; tools, materials, and equipment list; and 27 references. Seven units of…

  15. Electrode cartridge for pulse welding

    Energy Technology Data Exchange (ETDEWEB)

    Bonnen, John Joseph Francis; Golovashchenko, Sergey Fedorovich; Mamutov, Alexander; Maison, Lloyd Douglas

    2017-06-14

    A cartridge assembly for a tool includes a cartridge body or casing that contains a conductor. A conductor is connected to a pulse generator or source of stored charge that is discharged to vaporize the conductor and create an electro-hydraulic or electro-magnetic shockwave that is used to impact or pulse weld two parts together.

  16. Mixing weld gases offers advantages

    Science.gov (United States)

    May, J. L.; Mendenhall, M. M.

    1969-01-01

    Argon added to helium during gas tungsten arc cover-pass welding in the horizontal position results in a better controlled wider bead width, increased arc stability, and reduction in heat input. Adequate filler material wetness and penetration pass coverage is possible with only one pass.

  17. Welding the CNGS decay tube

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    3.6 km of welds were required for the 1 km long CERN Neutrinos to Gran Sasso (CNGS) decay tube, in which particles produced in the collision with a proton and a graphite target will decay into muons and muon neutrinos. Four highly skilled welders performed this delicate task.

  18. Investigate The Effect Of Welding Parameters On Mechanical Properties During The Welding Of Al-6061 Alloy

    Directory of Open Access Journals (Sweden)

    Rajendra Prasad

    2017-10-01

    Full Text Available Friction welding is a solid state welding technique which is being used in recent times to weld similar as well as dissimilar metals for getting defect free weld. Many combinations like low carbon to stainless steel austenitic to ferrite stainless steel aluminium to copper and titanium to aluminium or steel have been tried out by various solid state welding processes with quite good results. In the present work the 3 level full factorial design has been employed to investigate the effect of welding parameters on tensile strength toughness and heat generation during the welding of Al-6061 alloy. Mathematical relationships between friction welding parameters and mechanical properties like heat generation tensile strength and toughness have also been developed. An attempt has also been made to examine the fracture surfaces of test specimens using SEM. It has been found that welding speed is the most significant parameter thats affect the heat generation tensile strength and toughness. it has been found that tensile strength and toughness during welding increases with increased in welding speed while tensile strength and toughness initially increased as the welding time increases after that it decreased with increase in welding time. The difference in weight of alloying elements can be clearly seen by analyzing spectrum of elements.

  19. Welded joints integrity analysis and optimization for fiber laser welding of dissimilar materials

    Science.gov (United States)

    Ai, Yuewei; Shao, Xinyu; Jiang, Ping; Li, Peigen; Liu, Yang; Liu, Wei

    2016-11-01

    Dissimilar materials welded joints provide many advantages in power, automotive, chemical, and spacecraft industries. The weld bead integrity which is determined by process parameters plays a significant role in the welding quality during the fiber laser welding (FLW) of dissimilar materials. In this paper, an optimization method by taking the integrity of the weld bead and weld area into consideration is proposed for FLW of dissimilar materials, the low carbon steel and stainless steel. The relationships between the weld bead integrity and process parameters are developed by the genetic algorithm optimized back propagation neural network (GA-BPNN). The particle swarm optimization (PSO) algorithm is taken for optimizing the predicted outputs from GA-BPNN for the objective. Through the optimization process, the desired weld bead with good integrity and minimum weld area are obtained and the corresponding microstructure and microhardness are excellent. The mechanical properties of the optimized joints are greatly improved compared with that of the un-optimized welded joints. Moreover, the effects of significant factors are analyzed based on the statistical approach and the laser power (LP) is identified as the most significant factor on the weld bead integrity and weld area. The results indicate that the proposed method is effective for improving the reliability and stability of welded joints in the practical production.

  20. Intelligent hybrid system of welding parameters for robotic arc-welding task-level offline programming

    Science.gov (United States)

    Peng, Pai; Tian, Jiansong; Wu, Lin; Dai, Ming

    2000-10-01

    Welding process parameters are indispensable to program arc welding robot. To simplify off-line programming (OLP) for robotic arc welding, we develop an arc welding expert system whcih can generate welding process parameters automatically. Its input data came from the feature database of welding part, which is set up by our feature modeling system. The expert system has become an important module of our RAWTOLPS (Robotic Arc Welding Task-level Off-Line System). It combines case-based reasoning with heuristic rule-based reasoning methods to deal with the welding process design. Moreover, artificial neural networks are introduced to the systems for reasoning and machine learning, and several network modules are developed to learn from welding process database, based on back-propagation neural networks. After some groups of actual welding process data were used to train the network models, several network models are established to both design the welding process and to predict the weld bead shape. Besides the ANN-based learning, cased-based learning are used in the expert system. These two methods have respectively their own characteristics, and can meet qualifications of different users. The experimental data show that the system can accomplish re-learning and expanding of welding process knowledge, and satisfy the command of the off-line programming system.

  1. A unified model of coupled arc plasma and weld pool for double electrodes TIG welding

    Science.gov (United States)

    Wang, Xinxin; Fan, Ding; Huang, Jiankang; Huang, Yong

    2014-07-01

    A three-dimensional model containing tungsten electrodes, arc plasma and a weld pool is presented for double electrodes tungsten inert gas welding. The model is validated by available experimental data. The distributions of temperature, velocity and pressure of the coupled arc plasma are investigated. The current density, heat flux and shear stress over the weld pool are highlighted. The weld pool dynamic is described by taking into account buoyance, Lorentz force, surface tension and plasma drag force. The turbulent effect in the weld pool is also considered. It is found that the temperature and velocity distributions of the coupled arc are not rotationally symmetrical. A similar property is also shown by the arc pressure, current density and heat flux at the anode surface. The surface tension gradient is much larger than the plasma drag force and dominates the convective pattern in the weld pool, thus determining the weld penetration. The anodic heat flux and plasma drag force, as well as the surface tension gradient over the weld pool, determine the weld shape and size. In addition, provided the welding current through one electrode increases and that through the other decreases, keeping the total current unchanged, the coupled arc behaviour and weld pool dynamic change significantly, while the weld shape and size show little change. The results demonstrate the necessity of a unified model in the study of the arc plasma and weld pool.

  2. Automatic orbital GTAW welding: Highest quality welds for tomorrow's high-performance systems

    Science.gov (United States)

    Henon, B. K.

    1985-01-01

    Automatic orbital gas tungsten arc welding (GTAW) or TIG welding is certain to play an increasingly prominent role in tomorrow's technology. The welds are of the highest quality and the repeatability of automatic weldings is vastly superior to that of manual welding. Since less heat is applied to the weld during automatic welding than manual welding, there is less change in the metallurgical properties of the parent material. The possibility of accurate control and the cleanliness of the automatic GTAW welding process make it highly suitable to the welding of the more exotic and expensive materials which are now widely used in the aerospace and hydrospace industries. Titanium, stainless steel, Inconel, and Incoloy, as well as, aluminum can all be welded to the highest quality specifications automatically. Automatic orbital GTAW equipment is available for the fusion butt welding of tube-to-tube, as well as, tube to autobuttweld fittings. The same equipment can also be used for the fusion butt welding of up to 6 inch pipe with a wall thickness of up to 0.154 inches.

  3. CONTRIBUTIONS FROM SMOKE ON IMPACT OF WELDING PROCEDURES HEALTH OPERATORS WELDER

    Directory of Open Access Journals (Sweden)

    Gheorghe AMZA

    2012-05-01

    Full Text Available This paper presents research conducted on the contents of fumes resulting from welding processes with emphasis on micro various metallic and nonmetallic elements involved in these fumes. It also presents the main health effects of welders and operators working in the welding stations. Are risks that may occur due to micro chromium, nickel, iron, manganese, silicon, fluorine, zinc, aluminum, copper, cadmium, lead, molybdenum, cobalt, vanadium and others.

  4. The prediction of risk of welding defects at the procedure stage using computer knowledge based systems.

    OpenAIRE

    da Costa, S. C.

    1992-01-01

    The purpose of this research was to develop a methodology to evaluate the likelihood of defective welds as a procedure proposal is entered into a computerised database system. The approach developed was assessed for hydrogen induced cold cracking (HICC) since this defect is a major problem in welding technology. An expert system was used to implement the methodology. The information for the expert system knowledge base was partly gathered from previous work in this area. The...

  5. Calculation of the technological parameters of electrofusion welding of polyethylene pipes at low temperatures

    Science.gov (United States)

    Starostin, N. P.; Ammosova, O. A.

    2017-12-01

    The thermal process of electrofusion welding of polyethylene gas pipelines at air temperatures below the standard is investigated. The mathematical model used in the research takes into account the heat of the phase transition in the temperature interval. Computational experiments show the possibility of regulating the temperature regime for welding at low ambient air temperatures and providing the same temperature field variation in the thermal zone as with the permissible air temperatures.

  6. Identifying Combination of Friction Stir Welding Parameters to Maximize Strength of Lap Joints of AA2014-T6 Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Rajendrana C.

    2017-01-01

    Full Text Available AA2014 aluminum alloy (Al-Cu alloy has been widely utilized in fabrication of lightweight structures like aircraft structures, demanding high strength to weight ratio and good corrosion resistance. The fusion welding of these alloys will lead to solidification problems such as hot cracking. Friction stir welding is a new solid state welding process, in which the material being welded does not melt and recast. Lot of research works have been carried out by many researchers to optimize process parameters and establish empirical relationships to predict tensile strength of friction stir welded butt joints of aluminum alloys. However, very few investigations have been carried out on friction stir welded lap joints of aluminum alloys. Hence, in this investigation, an attempt has been made to optimize friction stir lap welding (FSLW parameters to attain maximum tensile strength using statistical tools such as design of experiment (DoE, analysis of variance (ANOVA, response graph and contour plots. By this method, it is found that maximum tensile shear fracture load of 12.76 kN can be achieved if a joint is made using tool rotational speed of 900 rpm, welding speed of 110 mm/min, tool shoulder diameter of 12 mm and tool tilt angle of 1.5°.

  7. Tomographical process monitoring of laser transmission welding with OCT

    Science.gov (United States)

    Ackermann, Philippe; Schmitt, Robert

    2017-06-01

    Process control of laser processes still encounters many obstacles. Although these processes are stable, a narrow process parameter window during the process or process deviations have led to an increase on the requirements for the process itself and on monitoring devices. Laser transmission welding as a contactless and locally limited joining technique is well-established in a variety of demanding production areas. For example, sensitive parts demand a particle-free joining technique which does not affect the inner components. Inline integrated non-destructive optical measurement systems capable of providing non-invasive tomographical images of the transparent material, the weld seam and its surrounding areas with micron resolution would improve the overall process. Obtained measurement data enable qualitative feedback into the system to adapt parameters for a more robust process. Within this paper we present the inline monitoring device based on Fourier-domain optical coherence tomography developed within the European-funded research project "Manunet Weldable". This device, after adaptation to the laser transmission welding process is optically and mechanically integrated into the existing laser system. The main target lies within the inline process control destined to extract tomographical geometrical measurement data from the weld seam forming process. Usage of this technology makes offline destructive testing of produced parts obsolete. 1,2,3,4

  8. Laser welding of tailored blanks

    Directory of Open Access Journals (Sweden)

    Peças, P.

    1998-04-01

    Full Text Available Laser welding has an incrising role in the automotive industry, namely on the sub-assemblies manufacturing. Several sheet-shape parts are laser welded, on a dissimilar combination of thicknesses and materials, and are afterwards formed (stamped being transformed in a vehicle body component. In this paper low carbon CO2 laser welding, on the thicknesses of 1,25 and 0,75 mm, formability investigation is described. There will be a description of how the laser welded blanks behave in different forming tests, and the influence of misalignment and undercut on the formibility. The quality is evaluated by measuring the limit strain and limit effective strain for the laser welded sheets and the base material, which will be presented in a forming limit diagram.

    A soldadura laser assume um papel cada vez mais importante na indústria automóvel, principalmente para a fabricação de sub-conjuntos constituídos por varias partes de chapa de diferentes espessuras (e diferentes materiais, que depois de estampados constituem um componente para integrar num veículo. Descreve-se neste artigo o trabalho de investigação de enformabilidade de chapa de ac.o de baixo carbono soldada por laser de CO2, nas espessuras de 1,25 e 0,75 mm. Apresenta-se uma descrição do comportamento das chapas soldadas por laser em diferentes testes de enformação, e a influência dos defeitos das soldaduras (desalinhamento e queda do banho-undercut no comportamento à enformação. A qualidade é avaliada pela medição da extensão limite e da extensão limite efectiva no material base e no material soldado, que serão representadas num diagrama de limite de enformabilidade.

  9. Electric pulse treatment of welded joint of aluminum alloy

    Directory of Open Access Journals (Sweden)

    A.A. Mitiaev

    2013-08-01

    Full Text Available Purpose. Explanation of the redistribution effect of residual strengthes after electric pulse treatment of ark welding seam of the aluminum alloy. Methodology. Alloy on the basis of aluminium of АК8М3 type served as the research material. As a result of mechanical treatment of the ingots after alloy crystallization the plates with 10 mm thickness were obtained. After edge preparation the elements, which are being connected were butt welded using the technology of semiautomatic argon arc welding by the electrode with a diameter of 3 mm of AK-5 alloy. Metal structure of the welded joint was examined under the light microscope at a magnification of 200 and under the scanning electronic microscope «JSM-6360 LA». The Rockwell hardness (HRF was used as a strength characteristic of alloy. Hardness measuring of the phase constituents (microhardness was carried out using the device PМТ-3, with the indenter loadings 5 and 10 g. The crystalline structure parameters of alloy (dislocation density, second kind of the crystalline grid distortion and the scale of coherent scattering regions were determined using the methods of X-ray structural analysis. Electric pulse treatment (ET was carried out on the special equipment in the conditions of the DS enterprise using two modes A and В. Findings. On the basis of researches the previously obtained microhardness redistribution effect in the area of welded connection after ET was confirmed. As a result of use of the indicated treatment it was determined not only the reduction of microhardness gradient but also the simultaneous hardening effect in the certain thermal affected areas near the welding seam. During study of chemical composition of phase constituents it was discovered, that the structural changes of alloy as a result of ET first of all are caused by the redistribution of chemical elements, which form the connections themselves. By the nature of the influence the indicated treatment can be

  10. Improving fatigue performance of rail thermite welds

    Directory of Open Access Journals (Sweden)

    Winiar L.

    2010-06-01

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

  11. Characterization of the Multi-Pass Weld Metal and the Effect of Post-Weld Heat Treatment on Its Microstructure and Toughness

    Science.gov (United States)

    Wang, Xuelin; Shang, Chengjia; Wang, Xuemin

    In multi-pass welding process, various thermal cycle of both weld metal (WM) and heat affected zone (HAZ) will be subjected several times. This will make the initial microstructure occur an irreversible transformation. As the transformed microstructure become extremely complex, the mechanical properties, especially the low temperature toughness are very much fluctuant. In this research, the microstructure and low temperature toughness of WM obtained from a real multi-pass weld joint (up to 55 mm) by submerged arc welding have been elaborated. The results indicated that the necklace-type coarse martensite-austenite (M-A) constituent formed in interlayer heat affected zone (IHAZ) of WM and the impact energy of WM at -40 °C was only 39 J. Furthermore, by conventional tempering with holding time of 30 min, the toughness of WM can't be effectively improved. However, by a new developed heat treatment process, the toughness of WM could be significantly improved, and it is believed to be caused by the composition of weld metal and the post-welding heat treatment process. It also shows that the decomposition of M-A constituent and formation of the retained austenite are the mechanism of the improvement of low temperature toughness.

  12. Welding of titanium and nickel alloy by combination of explosive welding and spark plasma sintering technologies

    Science.gov (United States)

    Malyutina, Yu. N.; Bataev, A. A.; Mali, V. I.; Anisimov, A. G.; Shevtsova, L. I.

    2015-10-01

    A possibility of titanium and nickel-based alloys composite materials formation using combination of explosive welding and spark plasma sintering technologies was demonstrated in the current research. An employment of interlayer consisting of copper and tantalum thin plates makes possible to eliminate a contact between metallurgical incompatible titanium and nickel that are susceptible to intermetallic compounds formation during their interaction. By the following spark plasma sintering process the bonding has been received between titanium and titanium alloy VT20 through the thin powder layer of pure titanium that is distinguished by low defectiveness and fine dispersive structure.

  13. 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.

  14. Simplified welding distortion analysis for fillet welding using composite shell elements

    Directory of Open Access Journals (Sweden)

    Mingyu Kim

    2015-05-01

    Full Text Available This paper presents the simplified welding distortion analysis method to predict the welding deformation of both plate and stiffener in fillet welds. Currently, the methods based on equivalent thermal strain like Strain as Direct Boundary (SDB has been widely used due to effective prediction of welding deformation. Regarding the fillet welding, however, those methods cannot represent deformation of both members at once since the temperature degree of freedom is shared at the intersection nodes in both members. In this paper, we propose new approach to simulate deformation of both members. The method can simulate fillet weld deformations by employing composite shell element and using different thermal expansion coefficients according to thickness direction with fixed temperature at intersection nodes. For verification purpose, we compare of result from experiments, 3D thermo elastic plastic analysis, SDB method and proposed method. Compared of experiments results, the proposed method can effectively predict welding deformation for fillet welds.

  15. 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.

  16. Risk Communication Concerning Welding Fumes for the Primary Preventive Care of Welding Apprentices in Southern Brazil

    OpenAIRE

    Cezar-Vaz, Marta Regina; Bonow, Clarice Alves; Cezar Vaz, Joana

    2015-01-01

    This study’s aim was to assess the perceptions of welding apprentices concerning welding fumes being associated with respiratory and cardiovascular disorders and assess the implementation of risk communication as a primary prevention tool in the welding training process. This quasi-experimental, non-randomized study with before-and-after design was conducted with 84 welding apprentices in Southern Brazil. Poisson Regression analysis was used. Relative Risk was the measure used with a 95% co...

  17. Analysis of factors affecting fractures of rails welded by alumino-thermic welding

    Directory of Open Access Journals (Sweden)

    Sergejs MIKHAYLOVS

    2008-01-01

    Full Text Available On Latvian Railway the use of the alumino-thermic welding is widespread using the Elektro-Thermit Company technology. Today it is a basic method for rail joints on railway switches. The analysis of the metal structure in the thermic welding and in the thermic welded zone of rails showed that the weld metal had inclusions small pores and nonmetallics. Pores and nonmetallics are not reduce hardness but it is concentrators of stresses and sources of cracks development.

  18. Prediction of numerical distortion after welding with various welding sequences and clampings

    Directory of Open Access Journals (Sweden)

    S. Kastelic

    2010-10-01

    Full Text Available Welding simulation of a test cover for hydropower plant was made due to very large dimensions of the cover. The main aim was to predict distortion after welding in order to avoid machining the cover. Welding process was simulated with the Sysweld program to keep distortion in desired limits. Various welding sequences and clamping conditions were calculated to reduce the distortion. Calculation of microstructure constituents in virtual complex geometry of joints was also analyzed.

  19. Influence of the Initial Fiber Orientation on the Weld Strength in Welding of Glass Fiber Reinforced Thermoplastics

    Directory of Open Access Journals (Sweden)

    Isabel Fiebig

    2016-01-01

    Full Text Available The welding factors are significantly lower in welding of fiber reinforced thermoplastics than in welding of unreinforced thermoplastics due to the fiber orientation in the weld. This paper presents results from investigations on the influence of the initial fiber orientation on the weld strength in hot plate and vibration welding for glass fiber reinforced polypropylene and polyamide 6. Injection molded specimens are compared to specimens with main initial fiber orientation being longitudinal and transverse to the joining direction. The results of CT analysis of the fiber orientation in the weld show the opportunity to achieve a higher weld strength by using specimens with fibers being initially oriented longitudinally to the joining direction. The influence of the initial fiber orientation in the parts to be welded on the weld strength in hot plate welding is more distinct than in vibration welding.

  20. Laser Peening Effects on Friction Stir Welding

    Science.gov (United States)

    Hatamleh, Omar

    2011-01-01

    Friction Stir Welding (FSW) is a welding technique that uses frictional heating combined with forging pressure to produce high strength bonds. It is attractive for aerospace applications. Although residual stresses in FSW are generally lower when compared to conventional fusion welds, recent work has shown that significant tensile residual stresses can be present in the weld after fabrication. Therefore, laser shock peening was investigated as a means of moderating the tensile residual stresses produced during welding. This slide presentation reviews the effect of Laser Peening on the weld, in tensile strength, strain, surface roughness, microhardness, surface wear/friction, and fatigue crack growth rates. The study concluded that the laser peening process can result in considerable improvement to crack initiaion, propagation and mechanical properties in FSW.

  1. Structural degradation of heterogeneous welded joints

    Directory of Open Access Journals (Sweden)

    Eva Schmidová

    2012-09-01

    Full Text Available Developing the techniques of welding materials with higher dynamic strength onto the rolling surfaces of rails is one of the options for increasing their operational endurance. The subject of this paper is an analyses of heterogeneous weld interfaces experimentally manufactured by welding medium-carbon austenitic steels onto high-carbon unalloyed pearlitic steels. The analyses focus on examinations of the marginal mixing of the materials at the weld interface and the circumstances under which intercrystalline cracks form in the weld deposit layers. Structural analyses, chemical microanalyses and a hardness assessment were performed in order to identify the corresponding structural changes. The proportion of zonal vs. interdendritic segregation of the alloying elements in the degradation of the welded joint was distinguished. We described the nature of the structural heterogeneities produced, locally connected with the martensitic transformation. The chemical heterogeneity leading to the formation of martensite at grain boundaries was identified as the limiting effect.

  2. Femtosecond fiber laser welding of dissimilar metals.

    Science.gov (United States)

    Huang, Huan; Yang, Lih-Mei; Bai, Shuang; Liu, Jian

    2014-10-01

    In this paper, welding of dissimilar metals was demonstrated for the first time, to the best of our knowledge, by using a high-energy high-repetition-rate femtosecond fiber laser. Metallurgical and mechanical properties were investigated and analyzed under various processing parameters (pulse energy, repetition rate, and welding speed). Results showed that the formation of intermetallic brittle phases and welding defects could be effectively reduced. Strong welding quality with more than 210 MPa tensile strength for stainless steel-aluminum and 175 MPa tensile strength for stainless steel-magnesium has been demonstrated. A minimal heat affected zone and uniform and homogenous phase transformation in the welding region have been demonstrated. This laser-welding technique can be extended for various applications in semiconductor, automobile, aerospace, and biomedical industries.

  3. Passively damped vibration welding system and method

    Science.gov (United States)

    Tan, Chin-An; Kang, Bongsu; Cai, Wayne W.; Wu, Tao

    2013-04-02

    A vibration welding system includes a controller, welding horn, an anvil, and a passive damping mechanism (PDM). The controller generates an input signal having a calibrated frequency. The horn vibrates in a desirable first direction at the calibrated frequency in response to the input signal to form a weld in a work piece. The PDM is positioned with respect to the system, and substantially damps or attenuates vibration in an undesirable second direction. A method includes connecting the PDM having calibrated properties and a natural frequency to an anvil of an ultrasonic welding system. Then, an input signal is generated using a weld controller. The method includes vibrating a welding horn in a desirable direction in response to the input signal, and passively damping vibration in an undesirable direction using the PDM.

  4. Friction Stir Welding of Steel Alloys

    Science.gov (United States)

    Ding, R. Jeffrey; Munafo, Paul M. (Technical Monitor)

    2001-01-01

    The friction stir welding process has been developed primarily for the welding of aluminum alloys. Other higher melting allows such, as steels are much more difficult to join. Special attention must be given to pin tool material selection and welding techniques. This paper addresses the joining of steels and other high melting point materials using the friction stir welding process. Pin tool material and welding parameters will be presented. Mechanical properties of weldments will also be presented. Significance: There are many applications for the friction stir welding process other than low melting aluminum alloys. The FSW process can be expanded for use with high melting alloys in the pressure vessel, railroad and ship building industries.

  5. Influence of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel welding joints

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhiqiang; Jing, Hongyang [School of Materials Science and Engineering, Tianjin University, Tianjin 300350 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300350 (China); Xu, Lianyong, E-mail: xulianyong@tju.edu.cn [School of Materials Science and Engineering, Tianjin University, Tianjin 300350 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300350 (China); Han, Yongdian; Zhao, Lei [School of Materials Science and Engineering, Tianjin University, Tianjin 300350 (China); Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300350 (China); Zhang, Jianli [Welding laboratory, Offshore Oil Engineering (Qing Dao) Company, Qing Dao 266520 (China)

    2017-02-01

    Highlights: • N{sub 2}-supplemented shielding gas promoted nitrogen solid-solution in the austenite. • Secondary austenite had higher Ni but lower Cr and Mo than primary austenite. • Pitting corrosion preferentially occurred at secondary austenite and Cr{sub 2}N. • Adding N{sub 2} in shielding gas improved pitting corrosion resistance of GTAW joint. • E2209T{sub 1} weld metal had very poor pitting corrosion resistance due to inclusions. - Abstract: The influences of microstructure and elemental partitioning on pitting corrosion resistance of duplex stainless steel joints welded by gas tungsten arc welding (GTAW) and flux-cored arc welding (FCAW) with different shielding gas compositions were studied by optical microscopy, electron backscatter diffraction, scanning electron microscopy, transmission electron microscopy, energy dispersive spectroscopy, electron probe microanalysis, and potentiostatic and potentiodynamic polarization methods The adding 2% N{sub 2} in shielding gas facilitated primary austenite formation in GTAW weld metal (WM) and suppressed Cr{sub 2}N precipitation in GTAW weld root. In the HAZ, the banded microstructure disappeared while the coarse ferrite grains maintained same orientation as the banded ferrite in the BM. In the WM, the ferrite had one single orientation throughout a grain, whereas several families of austenite appeared. The austenite both in BM and WM enriched in Ni and nitrogen, while Cr and Mo were concentrated in the ferrite and thus no element showed clear dendritic distribution in the WM (ER2209 and E2209T{sub 1}). In addition, the secondary austenite had higher Ni content but lower Cr and Mo content than the primary austenite. The N{sub 2}-supplemented shielding gas promoted nitrogen solid-solution in the primary and secondary austenite. Furthermore, the secondary austenite had relatively lower pitting resistance equivalent number (PREN) than the ferrite and primary austenite, thereby resulting in its preferential

  6. Control of welding distortion during gas metal arc welding of AH36 plates by stress engineering

    NARCIS (Netherlands)

    Pazooki, A.M.A.; Hermans, M.J.M.; Richardson, I.M.

    2017-01-01

    Welding residual stress and distortion are strongly linked together. One of the ways to control or reduce the welding distortions is the manipulation of the generated stresses during welding, and final residual stresses exist in the workpiece (stress engineering). In this paper, the control of gas

  7. Prediction of the weld pool geometry of TIG arc welding by using ...

    African Journals Online (AJOL)

    The present paper describes fuzzy logic simulation of tungsten inert gas welding (TIG) process to predict the weldment macrostructure zones' shape profile characteristics. The prediction of the weld pool geometry together with the shape of the heat affected zone (HAZ) was accomplished taking into account of TIG welding ...

  8. Numerical evaluation of multipass welding temperature field in API 5L X80 steel welded joints

    Directory of Open Access Journals (Sweden)

    J Nóbrega

    2016-10-01

    Full Text Available Many are the metallurgical changes suffered by materials when subjected to welding thermal cycle, promoting a considerable influence on the welded structures thermo mechanical properties. In project phase, one alternative for evaluating the welding cycle variable, would be the employment of computational methods through simulation. So, this paper presents an evaluation of the temperature field in a multipass welding of API 5L X80 steel used for oil and gas transportation, using the ABAQUS ® software, based on Finite Elements Method (FEM. During the simulation complex phenomena are considerable including: Variation in physical and mechanical properties of materials as a function of temperature, welding speed and the different mechanisms of heat exchange with the environment (convection and radiation were used. These considerations allow a more robust mathematical modeling for the welding process. An analytical heat source proposed by Goldak, to model the heat input in order to characterize the multipass welding through the GTAW (Gas Tungsten Arc Welding process on root and the SMAW (Shielded Metal Arc Welding process for the filling passes were used. So, it was possible to evaluate the effect of each welding pass on the welded joint temperature field, through the temperature peaks and cooling rates values during the welding process.

  9. The application of fuzzy theory for the control of weld line positions in injection-molded part.

    Science.gov (United States)

    Chen, Mei-Yung; Tzeng, Huan-Wen; Chen, Yi-Cheng; Chen, Shia-Chung

    2008-01-01

    This research proposes the fuzzy theory for the control of weld lines in plastic injection molding. The weld line occurs as a result of geometrical changes in molded parts in the injection molding process. The weld line is one of the defects present in plastic injection-molded parts; the line affects the quality of parts as well as the strength of the products. In the present study, fuzzy theory was applied in the design of injection molding. First, expert experiences were transformed into IF approximately THEN approximately rules to establish the knowledge base for developing fuzzy inference rules. The rules were then used to adjust the molding parameters, which in turn were applied to control the weld line position in the injection molding process. The results indicate that fuzzy theory exhibited favorable applicability in the control of the weld line as well as decreased the simulation time, thereby accelerating the design process of injection molding.

  10. Parameter optimization of flux-aided backing-submerged arc welding by using Taguchi method

    Science.gov (United States)

    Pu, Juan; Yu, Shengfu; Li, Yuanyuan

    2017-07-01

    Flux-aided backing-submerged arc welding has been conducted on D36 steel with thickness of 20 mm. The effects of processing parameters such as welding current, voltage, welding speed and groove angle on welding quality were investigated by Taguchi method. The optimal welding parameters were predicted and the individual importance of each parameter on welding quality was evaluated by examining the signal-to-noise ratio and analysis of variance (ANOVA) results. The importance order of the welding parameters for the welding quality of weld bead was: welding current > welding speed > groove angle > welding voltage. The welding quality of weld bead increased gradually with increasing welding current and welding speed and decreasing groove angle. The optimum values of the welding current, welding speed, groove angle and welding voltage were found to be 1050 A, 27 cm/min, 40∘ and 34 V, respectively.

  11. Width Criterion For Weld-Seam-Tracking Data

    Science.gov (United States)

    Lincir, Mark R.

    1993-01-01

    Image-processing algorithm in "through-torch-vision" (T3V) system developed to guide gas/tungsten arc welding robot along weld seam modified, according to proposal, reducing incidence of inaccurate tracking of weld seam. Developmental system intended to provide closed-loop control of motion of welding robot along weld seam on basis of lines in T3V image identified by use of image-processing algorithm and assumed to coincide with edges of weld seam. Use of width criterion prevents tracking of many false pairs of lines, with consequent decrease in incidence of inaccurate tracking and increase in confidence in weld-tracking capability of robotic welding system.

  12. A System for Complex Robotic Welding

    DEFF Research Database (Denmark)

    Madsen, Ole; Sørensen, Carsten Bro; Olsen, Birger

    2002-01-01

    This paper presents the architecture of a system for robotic welding of complex tasks. The system integrates off-line programming, control of redundant robots, collision-free motion planning and sensor-based control. An implementation for pipe structure welding made at Odense Steel Shipyard Ltd......., Denmark, demonstrates the system can be used for automatic welding of complex products in one-of-a-kind production....

  13. Numerical methods in simulation of resistance welding

    DEFF Research Database (Denmark)

    Nielsen, Chris Valentin; Martins, Paulo A.F.; Zhang, Wenqi

    2015-01-01

    Finite element simulation of resistance welding requires coupling betweenmechanical, thermal and electrical models. This paper presents the numerical models and theircouplings that are utilized in the computer program SORPAS. A mechanical model based onthe irreducible flow formulation is utilized...... a resistance welding point of view, the most essential coupling between the above mentioned models is the heat generation by electrical current due to Joule heating. The interaction between multiple objects is anothercritical feature of the numerical simulation of resistance welding because it influences...

  14. Heavy multi-pass TIG welding

    OpenAIRE

    Maske, Tomas

    2017-01-01

    This study aims to find the maximum, usable, feed limit at different arc-energies and use the findings in multi-pass welding planning for robotic welding, taking into consideration the high controllability of robot movements. A combined studies using numerical analyses and practical experiments to calculate the feed limits for different arc energies. Each weld where analysed both mathematical, physical and thru observation. The combined results for one experiment will form the bases for th...

  15. Occupational rhinitis due to steel welding fumes.

    Science.gov (United States)

    Castano, Roberto; Suarthana, Eva

    2014-12-01

    Exposure to welding fumes is a recognized respiratory hazard. Occupational asthma but not occupational rhinitis has been documented in workers exposed to steel welding fumes. We report a 26-year-old male with work-related rhinitis symptoms as well as lower airways symptoms suggestive of occupational asthma and metal fume fever associated with exposure to steel welding fumes. The diagnosis of occupational rhinitis was confirmed by specific inhalation challenge. © 2014 Wiley Periodicals, Inc.

  16. Effects Of Heat Sinks On VPPA Welds

    Science.gov (United States)

    Nunes, Arthur C.; Steranka, Paul O., Jr.

    1991-01-01

    Report describes theoretical and experimental study of absorption of heat by metal blocks in contact with metal plate while plate subjected to variable-polarity plasma-arc (VPPA) welding. Purpose of study to contribute to development of comprehensive mathematical model of temperature in weld region. Also relevant to welding of thin sheets of metal to thick blocks of metal, heat treatment of metals, and hotspots in engines.

  17. Controlling Arc Length in Plasma Welding

    Science.gov (United States)

    Iceland, W. F.

    1986-01-01

    Circuit maintains arc length on irregularly shaped workpieces. Length of plasma arc continuously adjusted by control circuit to maintain commanded value. After pilot arc is established, contactor closed and transfers arc to workpiece. Control circuit then half-wave rectifies ac arc voltage to produce dc control signal proportional to arc length. Circuit added to plasma arc welding machines with few wiring changes. Welds made with circuit cleaner and require less rework than welds made without it. Beads smooth and free of inclusions.

  18. Structural health monitoring of multi-spot welded joints using a lead zirconate titanate based active sensing approach

    Science.gov (United States)

    Yao, Ping; Kong, Qingzhao; Xu, Kai; Jiang, Tianyong; Huo, Lin-sheng; Song, Gangbing

    2016-01-01

    Failures of spot welded joints directly reduce the load capacity of adjacent structures. Due to their complexity and invisibility, real-time health monitoring of spot welded joints is still a challenge. In this paper, a lead zirconate titanate (PZT) based active sensing approach was proposed to monitor the structural health of multi-spot welded joints in real time. In the active sensing approach, one PZT transducer was used as an actuator to generate a guided stress wave, while another one, as a sensor, detected the wave response. Failure of a spot welded joint reduces the stress wave paths and attenuates the wave propagation energy from the actuator to the sensor. A total of four specimens made of dual phase steel with spot welds, including two specimens with 20 mm intervals of spot welded joints and two with 25 mm intervals, were designed and fabricated for this research. Under tensile tests, the spot welded joints successively failed, resulting in the PZT sensor reporting decreased received energy. The energy attenuations due to the failures of joints were clearly observed by the PZT sensor signal in both the time domain and frequency domain. In addition, a wavelet packet-based spot-weld failure indicator was developed to quantitatively evaluate the failure condition corresponding to the number of failed joints.

  19. The effect of laser surface melting on microstructure and corrosion behavior of friction stir welded aluminum alloy 2219

    Science.gov (United States)

    Ma, Shengchong; Zhao, Yong; Zou, Jiasheng; Yan, Keng; Liu, Chuan

    2017-11-01

    This study aimed to explore the electrochemical properties and microstructure of friction stir welds to understand the correlation between their properties and processing. Friction stir welding is a promising solid-state joining process for high-strength aluminum alloys (AA). Although friction stir welding (FSW) eliminates the problems of fusion welding due to the fact that it is performed below Tm, it causes severe plastic deformation in the material. Some AA welded by FSW exhibit relatively poor corrosion resistance. In this research, the corrosion resistance of such welds was enhanced through laser surface melting. A friction stir weld of AA 2219 was laser melted. The melt depth and microstructure were observed using optical and scanning electron microscopy. The melt zone exhibited epitaxially grown columnar grains. The redistribution of elemental composition was analyzed using energy-dispersive spectroscopy. The anticorrosion properties of both laser-melted and original welds were studied in aqueous 3.5% NaCl solution using cyclic potentiodynamic polarization. The results indicated a noticeable increase in the pitting corrosion resistance after the laser treatment on the surface. The repassivation potential was nobler than the corrosion potential after the laser treatment, confirming that the resistance to pitting growth improved.

  20. Effects of heat input on mechanical properties of metal inert gas welded 1.6 mm thick galvanized steel sheet

    Science.gov (United States)

    Rafiqul, M. I.; Ishak, M.; Rahman, M. M.

    2012-09-01

    It is usually a lot easier and less expensive to galvanize steel before it is welded into useful products. Galvanizing afterwards is almost impossible. In this research work, Galvanized Steel was welded by using the ER 308L stainless steel filler material. This work was done to find out an alternative way of welding and investigate the effects of heat input on the mechanical properties of butt welded joints of Galvanized Steel. A 13.7 kW maximum capacity MIG welding machine was used to join 1.6 mm thick sheet of galvanized steel with V groove and no gap between mm. Heat inputs was gradually increased from 21.06 to 25.07 joules/mm in this study. The result shows almost macro defects free welding and with increasing heat input the ultimate tensile strength and welding efficiency decrease. The Vickers hardness also decreases at HAZ with increasing heat input and for each individual specimen; hardness was lowest in heat affected zone (HAZ), intermediate in base metal and maximum in welded zone. The fracture for all specimens was in the heat affected zone while testing in the universal testing machine.