WorldWideScience

Sample records for braze welding technique

  1. Joining of beryllium by braze welding technique: preliminary results

    Energy Technology Data Exchange (ETDEWEB)

    Banaim, P.; Abramov, E. [Ben-Gurion Univ. of the Negev, Beersheba (Israel); Zalkind, S.; Eden, S.

    1998-01-01

    Within the framework of some applications, there is a need to join beryllium parts to each other. Gas Tungsten Arc Braze Welds were made in beryllium using 0.3 mm commercially Aluminum (1100) shim preplaced at the joint. The welds exhibited a tendency to form microcracks in the Fusion Zone and Heat Affected Zone. All the microcracks were backfilled with Aluminum. (author)

  2. Braze welding of cobalt with a silver–copper filler

    Directory of Open Access Journals (Sweden)

    Everett M. Criss

    2015-01-01

    Full Text Available A new method of joining cobalt by braze-welding it with a silver–copper filler was developed in order to better understand the residual stresses in beryllium–aluminum/silicon weldments which are problematic to investigate because of the high toxicity of Be. The base and filler metals of this new welding system were selected to replicate the physical properties, crystal structures, and chemical behavior of the Be–AlSi welds. Welding parameters of this surrogate Co–AgCu system were determined by experimentation combining 4-point bending tests and microscopy. Final welds are 5 pass manual TIG (tungsten inert gas, with He top gas and Ar back gas. Control of the welding process produces welds with full penetration melting of the cobalt base. Microscopy indicates that cracking is minimal, and not through thickness, whereas 4-point bending shows failure is not by base-filler delamination. These welds improve upon the original Be–AlSi welds, which do not possess full penetration, and have considerable porosity. We propose that utilization of our welding methods will increase the strength of the Be–AlSi weldments. The specialized welding techniques developed for this study may be applicable not only for the parent Be–AlSi welds, but to braze welds and welds utilizing brittle materials in general. This concept of surrogacy may prove useful in the study of many different types of exotic welds.

  3. Welding and brazing of the JET machine components

    International Nuclear Information System (INIS)

    The report covers the techniques used for joining the various parts of the machine. The difficulties encountered during the welding and brazing of similar and dissimilar metals are underlined and the solutions adopted to solve them are indicated. The vast experience gained by those involved in the processes of joining the various parts of the JET machine components, and the lessons learnt are summarized in this report. (author)

  4. Improved Assembly for Gas Shielding During Welding or Brazing

    Science.gov (United States)

    Gradl, Paul; Baker, Kevin; Weeks, Jack

    2009-01-01

    An improved assembly for inert-gas shielding of a metallic joint is designed to be useable during any of a variety of both laser-based and traditional welding and brazing processes. The basic purpose of this assembly or of a typical prior related assembly is to channel the flow of a chemically inert gas to a joint to prevent environmental contamination of the joint during the welding or brazing process and, if required, to accelerate cooling upon completion of the process.

  5. Brazing and inertia welding of dissimilar metal tubing

    International Nuclear Information System (INIS)

    A movable pump limiter is currently being built for the Tore Supra tokamak in Cadarace, France. Part of the assembly has dispersion-strengthened Cu cooling tubes joined to an AISI 316L stainless steel transition sleeve. The steel sleeve is subsequently welded into a 315L manifold. This study was made to evaluate the feasibility of brazing or inertia welding the dissimilar metal, tubing-sleeve transition. An alumina-strengthened copper alloy (DSCu) was selected for the module cooling tubes. The 316L transition pieces varied in diameter from the same nominal size as the DSCu pieces when inertial welding, to a 12.7 mm (1/2 in.) O.D. to accommodate a lap joint when brazing. The wall thickness of the inertia welded 316L pieces was varied to determine the overlap effect on the weld quality. Ag-28Cu, Ag-27.6Cu-4.5Ti, Au-37Cu-3In, and Au-18Ni (wt%) filler metals were chosen for brazing and the braze microstructures and strengths were evaluated. The best wetting was achieved with the Au based filler metals. All of the brazed joints were hydrostatically pressure tested to 10.34 MPa (1500 psi) without a failure. In all cases, an excellent metallurgical bond with a relatively small cold worked region was produced. The inertia welded samples were also pressure and tensile tested under the same test conditions that were used to evaluate the brazed samples. The welds passed the 10.34 MPa hydrostatic pressure inspection and failed under a tensile load in the DSCu piece away form the weld interface. Brazing and inertia welding were successfully used to join DSCu to 316L. The Au-based filler metals produced the best brazes with joint strengths of 480 MPa. The inertia welds had slightly higher strengths, but both failed away from the joint in the DSCu tube. All of these samples passed a 10.34 MPa hydrostatic pressure test. These processes allow flexibility in designing and fabricating a dissimilar metal transition joint

  6. THERMAL FIELD MODELING IN THE MIG / MAG - CMT BRAZE-WELDING PROCESS OF GALVANIZED SHEETS

    OpenAIRE

    GHEORGHE SIMA; ELENA STELA MUNCUT

    2013-01-01

    This paper deals with some technical aspects of the optimization process braze-welding of galvanized steel sheet with a thickness of 0.7-1.5 mm. The braze-welding process is presented systemic, highlighting the input and output variables (of the zinc layer and intermetallic layer characteristics). It is presented the test for statistical analysis performed on a four-level factorial experiment aimed at studying the influence of the main simultaneously welding parameters of the welding technolo...

  7. Corrosion Behavior of Aluminum-Steel Weld-Brazing Joint

    Science.gov (United States)

    Shi, Yu; Li, Jie; Zhang, Gang; Huang, Jiankang; Gu, Yufen

    2016-05-01

    Dissimilar metals of 1060 aluminum and galvanized steel were joined with a lap joint by pulsed double-electrode gas metal arc weld brazing with aluminum-magnesium and aluminum-silicon filler metals. The corrosion behavior of the weld joints was investigated with immersion corrosion and electrochemical corrosion tests, and the corrosion morphology of the joints was analyzed with scanning electron microscopy (SEM). Galvanic corrosion was found to occur when the samples were immersed in corrosive media, and the corrosion rate of joints was increased with increased heat input of the workpiece. Comparison of the corrosion properties of weld joints with different filler wires indicated that the corrosion rate of weld joints with aluminum-silicon filler wire was larger than that of weld joints with aluminum-magnesium filler wire. Results also showed that the zinc-rich zone of weld joints was prone to corrosion. The corrosion behavior of zinc-rich zone was analyzed with SEM equipped with an energy-dispersive x-ray spectroscopy analysis system based on the test results.

  8. THERMAL FIELD MODELING IN THE MIG / MAG - CMT BRAZE-WELDING PROCESS OF GALVANIZED SHEETS

    Directory of Open Access Journals (Sweden)

    GHEORGHE SIMA

    2013-10-01

    Full Text Available This paper deals with some technical aspects of the optimization process braze-welding of galvanized steel sheet with a thickness of 0.7-1.5 mm. The braze-welding process is presented systemic, highlighting the input and output variables (of the zinc layer and intermetallic layer characteristics. It is presented the test for statistical analysis performed on a four-level factorial experiment aimed at studying the influence of the main simultaneously welding parameters of the welding technology CMT (Cold Metal Transfer: determining an optimal welding current IS, welding speed vS, boos current Ina and arc length correction factor l0.

  9. Braze Welding TIG of Titanium and Aluminium Alloy Type Al – Mg

    Directory of Open Access Journals (Sweden)

    Winiowski A.

    2016-03-01

    Full Text Available The article presents the course and the results of technological tests related to TIG-based arc braze welding of titanium and AW-5754 (AlMg3 aluminium alloy. The tests involved the use of an aluminium filler metal (Al99.5 and two filler metals based on Al-Si alloys (AlSi5 and AlSi12. Braze welded joints underwent tensile tests, metallographic examinations using a light microscope as well as structural examinations involving the use of a scanning electron microscope and an X-ray energy dispersive spectrometer (EDS. The highest strength and quality of welds was obtained when the Al99.5 filler metal was used in a braze welding process. The tests enabled the development of the most convenient braze welding conditions and parameters.

  10. Ultrasonic inspection of the brazed joint and explosive welds used to repair the PFR evaporators

    International Nuclear Information System (INIS)

    A small number of in-service failures associated with the steam-tube to tube-plate welds of the PFR evaporators led to the decision to protect the welds by sleeving. The philosophy was to insert a sleeve through the tube-plate and into the steam tube, thus bridging the existing weld. The top portion of the sleeve was to be explosively welded to the zone adjacent to the top face of the tube-plate and the lower portion brazed into the steam tube. This paper deals with the development and use of ultrasonics to test both the brazed and explosively welded joints

  11. Brazing handbook

    CERN Document Server

    American Welding Society

    2007-01-01

    By agreement between the American Welding Society C3 Committee on Brazing and Soldering and the ASM Handbook Committee, the AWS Brazing Handbook has been formally adopted as part of the ASM Handbook Series. Through this agreement, the brazing content in the ASM Handbook is significantly updated and expanded. The AWS Brazing Handbook, 5th Edition provides a comprehensive, organized survey of the basics of brazing, processes, and applications. Addresses the fundamentals of brazing, brazement design, brazing filler metals and fluxes, safety and health, and many other topics. Includes new chapters on induction brazing and diamond brazing.

  12. Brazing

    International Nuclear Information System (INIS)

    This report is a compilation of published literature on high temperature brazing covering the period 1973-1978. The references are listed alphabetically with regard to the base material or combination of base materials to be brazed. Trade names are treated as base materials. The report contains approximately 1500 references, of which 300 are to patents

  13. A Recent Welding Technique: Laser Welding

    OpenAIRE

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

    2013-01-01

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

  14. 75 FR 52037 - Welding, Cutting and Brazing Standard; Extension of the Office of Management and Budget's (OMB...

    Science.gov (United States)

    2010-08-24

    ... Order No. 5-2007 (67 FR 31160). Signed at Washington, DC, on August 16, 2010. David Michaels, Assistant... Occupational Safety and Health Administration Welding, Cutting and Brazing Standard; Extension of the Office of... the information collection requirements contained in the Welding, Cutting and Brazing Standard (29...

  15. Joining mechanism of Ti/Al dissimilar alloys during laser welding-brazing process

    International Nuclear Information System (INIS)

    Research highlights: → The microstructures of interfacial zones were confirmed in detail by transmission electron microscope (TEM). Interfacial reaction layers of brazing joint were composed of α-Ti, nanosize granular Ti7Al5Si12 and serration-shaped TiAl3. For the first time, obvious stacking fault structure in intermetallic phase TiAl3 was found when the thickness of the reaction layer was very thin (approximately below 1 μm). → Metallurgical characteristics for laser welding-brazing process in the environment of far from equilibrium was expounded by microstructures of the joints, the characteristics of thermal process and element diffusion behavior. - Abstract: Joining mechanism of Ti/Al dissimilar alloys was investigated during laser welding-brazing process with automated wire feed. The microstructures of fusion welding and brazing zones were analysed in details by transmission electron microscope (TEM). It was found that microstructures of fusion welding zone consist of α-Al grains and ternary near-eutectic structure with α-Al, Si and Mg2Si. Interfacial reaction layers of brazing joint were composed of α-Ti, nanosize granular Ti7Al5Si12 and serration-shaped TiAl3. For the first time, apparent stacking fault structure in intermetallic phase TiAl3 was found when the thickness of the reaction layer was very thin (approximately less than 1 μm). Furthermore, crystallization behavior of fusion zone and mechanism of interfacial reaction were discussed in details.

  16. Reversible brazing process

    Science.gov (United States)

    Pierce, Jim D.; Stephens, John J.; Walker, Charles A.

    1999-01-01

    A method of reversibly brazing surfaces together. An interface is affixed to each surface. The interfaces can be affixed by processes such as mechanical joining, welding, or brazing. The two interfaces are then brazed together using a brazing process that does not defeat the surface to interface joint. Interfaces of materials such as Ni-200 can be affixed to metallic surfaces by welding or by brazing with a first braze alloy. The Ni-200 interfaces can then be brazed together using a second braze alloy. The second braze alloy can be chosen so that it minimally alters the properties of the interfaces to allow multiple braze, heat and disassemble, rebraze cycles.

  17. Dissimilar metals TIG welding-brazing of aluminum alloy to galvanized steel

    Institute of Scientific and Technical Information of China (English)

    San-bao LIN; Jian-ling SONG; Guang-chao MA; Chun-li YANG

    2009-01-01

    Dissimilar metals TIG welding-brazing of aluminum alloy to galvanized steel was investigated, and the wettability and spreadability of aluminum filler metal on the steel surface were analyzed. The resultant joint was characterized in order to determine the brittle intermetallic compound (IMC) in the interfacial layer, and the mechan-ical property of the joint was tested. The results show that the zinc coated layer can improve the wettability and spreadability of liquid aluminum filler metal on the surface of the steel, and the wetting angle can reach less than 20°. The lap joint has a dual characteristic and can be divided into a welding part on the aluminum side and a brazing part on the steel side. The interfacial IMC layer in the steel side is about 9.0 μm in thickness, which transfers from (α-Al + FeAl3) in the welded seam side to (Fe2Al5+ FeAl2) and (FeAl2+ FeAl) in the steel side. The crystal grain of the welded seam is obviously larger in size in the aluminum side. The local incomplete brazing is found at the root of the lap joint, which weakens the property of the joint. The fracture of the joint occurs at the root and the average tensile strength reaches 90 MPa.

  18. Evaluation of Laser Braze-welded Dissimilar Al-Cu Joints

    Science.gov (United States)

    Schmalen, Pascal; Plapper, Peter

    The thermal joining of Aluminum and Copper is a promising technology towards automotive battery manufacturing. The dissimilar metals Al-Cu are difficult to weld due to their different physicochemical characteristics and the formation of intermetallic compounds (IMC), which have reduced mechanical and electric properties. There is a critical thickness of the IMCs where the favored mechanical properties of the base material can be preserved. The laser braze welding principle uses a position and power oscillated laser-beam to reduce the energy input and the intermixture of both materials and therefore achieves minimized IMCs thickness. The evaluation of the weld seam is important to improve the joint performance and enhance the welding process. This paper is focused on the characterization and quantification of the IMCs. Mechanical, electrical and metallurgical methods are presented and performed on Al1050 and SF-Cu joints and precise weld criteria are developed.

  19. Underwater YAG laser welding technique

    International Nuclear Information System (INIS)

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

  20. Improving interfacial reaction nonhomogeneity during laser welding-brazing aluminum to titanium

    International Nuclear Information System (INIS)

    Highlights: → Interfacial reaction nonhomogeneity of laser welding-brazing was improved. → The process window was extended by rectangular spot combined with V-shaped groove. → Mechanical property and its stability of Ti/Al dissimilar joint were enhanced. -- Abstract: Heterogeneous interfacial reactions were easily found along the Ti/Al interface due to high temperature gradient during laser welding-brazing of Ti/Al dissimilar alloys. To improve the nonhomogeneity, relative uniform energy distribution of laser beam and appropriate groove were attempted. The effects of these attempts on the nonhomogeneity of interfacial reactions were investigated by finite element method (FEM) numerical simulation and experimental validation. The results indicate that the V-shaped groove can make the interface roughly parallel to the isotherm of the temperature field. Moreover, the rectangular spot laser can further improve homogenization of the interfacial reaction along the interface in comparison with circular spot laser. Tensile test results show that the combination of rectangular spot laser welding-brazing and V-shaped groove can effectively control the fracture of Ti/Al joints in the seam in a wide processing parameters window, and the average tensile strength reaches 278 MPa.

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

    Directory of Open Access Journals (Sweden)

    J. Matusiak

    2016-04-01

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

  2. Mechanical characteristics of laser braze-welded aluminium-copper connections

    Science.gov (United States)

    Solchenbach, Tobias; Plapper, Peter

    2013-12-01

    The mechanical characteristics of dissimilar Al-Cu connections, joined by a novel, robust laser braze-welding process are reported. A fiber laser is used in combination with a 2D galvoscanner to provide spatial power modulation by superposed circular beam oscillation. With the help of statistical experimental design, a broad range of processing parameters has been investigated in order to understand their effects on the joint characteristics. A maximum shear strength of 121 MPa has been detected within the scope of the experiments.

  3. Control of microstructure in soldered, brazed, welded, plated, cast or vapor deposited manufactured components

    Science.gov (United States)

    Ripley, Edward B.; Hallman, Russell L.

    2015-11-10

    Disclosed are methods and systems for controlling of the microstructures of a soldered, brazed, welded, plated, cast, or vapor deposited manufactured component. The systems typically use relatively weak magnetic fields of either constant or varying flux to affect material properties within a manufactured component, typically without modifying the alloy, or changing the chemical composition of materials or altering the time, temperature, or transformation parameters of a manufacturing process. Such systems and processes may be used with components consisting of only materials that are conventionally characterized as be uninfluenced by magnetic forces.

  4. 78 FR 53159 - Standard for Welding, Cutting, and Brazing; Extension of the Office of Management and Budget's...

    Science.gov (United States)

    2013-08-28

    ... Paperwork Reduction Act of 1995 (44 U.S.C. 3506 et seq.) and Secretary of Labor's Order No. 1-2012 (77 FR... Occupational Safety and Health Administration Standard for Welding, Cutting, and Brazing; Extension of the... Budget's (OMB) approval of the information collection requirements contained in the Standard for...

  5. Brazing techniques for side-coupled electron accelerator structures

    International Nuclear Information System (INIS)

    The collaboration between the Los Alamos National Laboratory and the National Bureau of Standards (NBS), started in 1979, has led to the development of an advanced c-w microtron accelerator design. The four 2380-MHz NBS accelerating structures, containing a total of 184 accelerating cavities, have been fabricated and delivered. New fabrication methods, coupled with refinements of hydrogen-furnace brazing techniques described in this paper, allow efficient production of side-coupled structures. Success with the NBS RTM led to Los Alamos efforts on similar 2450-MHz accelerators for the microtron accelerator operated by the Nuclear Physics Department of the University of Illinois. Two accelerators (each with 17 cavities) have been fabricated; in 1986, a 45-cavity accelerator is being fabricated by private industry with some assistance from Los Alamos. Further private industry experience and refinement of the described fabrication techniques may allow future accelerators of this type to be completely fabricated by private industry

  6. 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.

  7. Welding Techniques for In-Pile Instrumentation at INR Pitesti

    International Nuclear Information System (INIS)

    Welding is widely involved in developing in-pile instrumentation, regarding both attaching sensors and joining components of the in-pile experimental devices. Although new methods were not developed, we combined existing techniques, aiming to master them and to ensure reproducibility, sensitivity, robustness, and fast response (for sensor welding). In this paper we present results regarding thermocouple welded on cladding, and dissimilar joints. Techniques for welding K-type thermocouples on cladding were designated to ensure robust joints able to resist during pressure and temperature transients, to minimize the perturbation on temperature field and on the cladding material structure, to reproduce the joint shape and dimension, and to ensure fast response. Welded or brazed joints between materials with properties suitable to nuclear applications are often required for in-pile instrumentation to allow coupling to other components of the experimental devices. The paper describes work related to Zircaloy-to-Stainless Steel joint through eutectic vacuum brazing. The eutectic was produced by thermal diffusion of the elements in the base materials at their interface, through formation of liquid phases of Zr-Fe and Zr-Ni systems at the Zy-SS interface. Clean, reduced roughness, oxide-free contact interface, and precise temperature control were aimed. The optimal interface was the joint on perfectly matching truncated cone surfaces. Heating to 1030oC was obtained through vacuum induction at 10 kHz frequency, with vacuum between 10-5 and 10-6 mbar. Other dissimilar joints were micro-TIG welds on SS capillary connected to Inconel-Incoloy capsules, for high pressure measurement lines with small internal volume. To evaluate the joints burst tests (for thermocouple welding only) polarized light metallography, macrography, backscattered electron tests, Helium leak test, tensile test, and thermal cycling tests were performed. (author)

  8. The Role of Zinc Layer During Wetting of Aluminium on Zinc-coated Steel in Laser Brazing and Welding

    Science.gov (United States)

    Gatzen, M.; Radel, T.; Thomy, C.; Vollertsen, F.

    The zinc layer of zinc-coated steel is known to be a crucial factor for the spreading of liquid aluminium on the coated surface. For industrial brazing and welding processes these zinc-coatings enable a fluxless joining between aluminium and steel in many cases. Yet, the reason for the beneficial effect of the zinc to the wetting process is not completely understood. Fundamental investigations on the wetting behaviour of single aluminium droplets on different zinc-coated steel surfaces have revealed a distinct difference between coated surfaces at room temperature and at elevated temperature regarding the influence of different coating thicknesses. In this paper the case of continuous laser brazing and welding processes of aluminium and commercial galvanized zinc-coated steel sheets are presented. It is shown that in the case of bead-on-plate laser beam brazing, the coating thickness has a measureable effect on the resulting wetting angle and length but does not have a significant impact in case of overlap laser beam welding. This might be linked to different heat transfer conditions. The results also strongly indicate that proper initialbreakup of oxide layers is still required to accomplish good wetting on zinc-coated surfaces.

  9. Dissimilar Laser Welding/Brazing of 5754 Aluminum Alloy to DP 980 Steel: Mechanical Properties and Interfacial Microstructure

    Science.gov (United States)

    Yang, Jin; Li, Yulong; Zhang, Hua; Guo, Wei; Weckman, David; Zhou, Norman

    2015-11-01

    A diode laser welding/brazing technique was used for lap joining of 5754 aluminum alloy to DP 980 steel with Al-Si filler metal. The correlation between joint interfacial microstructure, wettability of filler metal, and mechanical properties was systematically investigated. At low laser power (1.4 kW), a layer of intermetallic compounds, composed of θ-Fe(Al,Si)3 and τ 5 -Al7.2Fe1.8Si, was observed at the interface between fusion zone and steel. Because of the poor wettability of filler metal on the steel substrate, the joint strength was very low and the joint failed at the FZ/steel interface. When medium laser power (2.0 kW) was applied, the wettability of filler metal was enhanced, which improved the joint strength and led to FZ failure. With further increase of laser power to 2.6 kW, apart from θ and τ 5, a new hard and brittle η-Fe2(Al,Si)5 IMC with microcracks was generated at the FZ/steel interface. The formation of η significantly degraded the joint strength. The failure mode changed back to interfacial failure.

  10. Development of brazing technique for a 1.6 cell BNL/SLAC/UCLA type photocathode guns by hydrogen brazing

    International Nuclear Information System (INIS)

    Two prototypes of a 1.6 cell BNL/SLAC/UCLA type RF photocathode gun, a precision machined RF structure capable of supporting gradients in excess of 80 MV/m, have been successfully brazed and leak rates of 10-10 mbar l/s have been achieved. Brazing, is carried out in two steps in a hydrogen furnace, it involves joining of two RF cavities, 6 cylindrical ports, one rectangular waveguide and one seal plate. The cavities and waveguide are made of copper and the ports and seal plate are of stainless steel. Fixtures were designed and fabricated indigenously to maintain the required assembly tolerances during brazing. This was important for brazing of ports, two of which are brazed to one cavity at an angle of 22.50 at diametrically opposite locations, and the remaining four are brazed to the other cavity in mutually perpendicular orientations. All joints were brazed using copper-silver eutectic (72-28) alloy in foil and wire forms. This paper discusses the brazing requirement, design of fixtures, and the procedure adopted for brazing of the photocathode gun. The paper also discusses results of the tests carried out to qualify the brazed joints. (author)

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

    Directory of Open Access Journals (Sweden)

    Ms. Deepika Harwani

    2014-12-01

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

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

    OpenAIRE

    Ms. Deepika Harwani; Mr. Kapil Banker

    2014-01-01

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

  13. Tensile Strength of Welded Joint of 1Cr18Ni9 Stainless Steel and Nb-1Zr Alloy Jointed by Electron Beam Self-material Brazing

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Compared with Nb-1Zr alloy stainless steels have a quite difference in melting point, thermalphysical and electromagnetism properties etc.. Therefore, it is very difficulty to joint by melting weldingmethod. Electron beam self-brazing method is an accepted method to use for this kind of welding. Make

  14. Low activation brazing materials and techniques for SiC f/SiC composites

    Science.gov (United States)

    Riccardi, B.; Nannetti, C. A.; Petrisor, T.; Sacchetti, M.

    2002-12-01

    A low activation brazing technique for silicon carbide fiber reinforced silicon carbide matrix composites (SiC f/SiC) is presented; this technique is based on the use of the 78Si-22Ti (wt%) eutectic alloy. The joints obtained take advantage of a melting point able to avoid composite fibre-interface degradation. All the joints showed absence of discontinuities and defects at the interface and a fine eutectic structure. Moreover, the joint layer appeared well adherent both to the matrix and the fibre interphase and the brazing alloy infiltration looked sufficiently controlled. The joints of SiC f/SiC composites showed 71±10 MPa almost pure shear strength at RT and up to 70 MPa at 600 °C.

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

    Institute of Scientific and Technical Information of China (English)

    Shujun WANG; Guoliang QIN; Yuhu SU

    2013-01-01

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

  16. 49 CFR 178.51 - Specification 4BA welded or brazed steel cylinders.

    Science.gov (United States)

    2010-10-01

    ... the thickness of shell metal. (iii) Longitudinal seams in shells must be made by copper brazing... least eight times the thickness of plate, laps being held in position, substantially metal to metal, by... table 1 of appendix A to this part, for the particular material under consideration; (ii) One-half...

  17. 异种合金激光熔钎焊研究进展%Progress in Laser Fusion Welding-Brazing of Dissimilar Alloys

    Institute of Scientific and Technical Information of China (English)

    肖荣诗; 董鹏; 赵旭东

    2011-01-01

    激光熔钎焊是利用两种合金熔点的差异,通过激光加热使低熔点材料(母材和填充材料)熔化,在接头界面与固态高熔点母材相互作用达到冶金结合的异种合金连接方法.按激光能量吸收机制对激光熔钎焊进行了分类,并结合所做工作,阐述了激光熔钎焊方法的发展及研究进展.%Laser fusion welding-brazing processes are methods to metallurgically join dissimilar alloys with different melting points by laser heating to melt materials (substrate and filler material) with lower melting point, and by the interaction between the weld pool and the solid substrate with higher melt point at the joint interface. Laser fusion welding-brazing processes of dissimilar alloys are classified according to the laser energy absorption mechanisms. The development and state of the art of laser fusion welding-brazing processes are reviewed.

  18. Techniques for laser welding polymeric devices.

    Science.gov (United States)

    Jones, I A

    2003-04-01

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

  19. Secondary ledeburite formation during various welding techniques

    Directory of Open Access Journals (Sweden)

    Tonkovič M.P.

    2015-01-01

    Full Text Available The occurrence and formation sequence of secondary ledeburite in the heat affected zone of chromium ledeburitic tool steel W.Nr. 1.2379 (OCR12 VM after welding with SAW, TIG, microplasma and laser welding techniques is presented in this paper. Special attention was paid on the behaviour of carbides. The occurrence of secondary ledeburite is a result of local enrichment of the austenite matrix with alloying elements, due to partial or complete dissolution of primary/eutectic carbides. The results show that the largest amount of secondary ledeburite is formed during submerged arc welding, followed by TIG and microplasma welding technique. Welding by laser technique, with appropriate technological parameters, could prevent secondary ledeburite formation.

  20. Nd:YAG Laser Melting-Brazing Welding Between 5052 Aluminum and Galvanized Steel%5052铝/镀锌钢Nd:YAG激光熔-钎焊

    Institute of Scientific and Technical Information of China (English)

    石岩; 邝玉林; 刘佳; 张宏

    2012-01-01

    利用Nd:YAG激光器实现了5052铝/镀锌钢异种金属板材之间的熔-钎焊连接,并对焊缝成形、接头性能及微观形貌做了分析.分析结果表明,合适的热输入能够有效实现5052铝/镀锌钢异种金属之间的熔-钎焊连接,焊接接头中铝合金母材发生熔化与镀锌钢形成钎焊连接,镀锌钢母材并未发生熔化;焊接接头的抗拉强度为128 N/mm;微观形貌分析表明,在焊缝钎接界面处生成了一层薄金属间化合物层,金属间化合物层的厚度为3~4 μm.%The melting-brazing connection of the dissimilar metal 5052 aluminum alloy/galvanized steel was achieved by using the Nd:YAG laser, and the weld formation, joint performance and microstructure of joint was analyzed. The analysis result indicates that, it can achieve successful melting-brazing connection of 5052 aluminum alloy/galvanized steel, the aluminum in the joint melted and formed a brazed joint with galvanized steel, the galvanized steel hadn't melt; tensile strength of welded joint can be high as 128 N/mm; the microstructure showed that, a thin intermetallic compound layer is generated on the welded brazing interface, its thickness is 3~4 μm.

  1. Innovative Tools Advance Revolutionary Weld Technique

    Science.gov (United States)

    2009-01-01

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

  2. Potential and limitations of microanalysis SEM techniques to characterize borides in brazed Ni-based superalloys

    International Nuclear Information System (INIS)

    Brazed Ni-based superalloys containing complex phases of different Boron contents remain difficult to characterize at the micrometer scale. Indeed Boron is a light element difficult to measure precisely. The state-of-the-art microanalysis systems have been tested on a single crystal MC2 based metal brazed with BNi-2 alloy to identify boride precipitates. Effort has been made to evaluate the accuracy in Boron quantitation. Energy-dispersive and wavelength-dispersive X-ray spectroscopy attached to a Scanning Electron Microscope have first been used to determine the elemental composition of Boron-free phases, and then applied to various types of borides. Results have been compared to the ones obtained using a dedicated electron probe microanalysis, considered here as the reference technique. The most accurate method to quantify Boron using EDS is definitely by composition difference. A precision of 5 at.% could be achieved with optimized data acquisition and post-processing schemes. Attempts that aimed at directly quantifying Boron with various standards using EDS or coupled EDS/WDS gave less accurate results. Ultimately, Electron Backscatter Diffraction combined with localized EDS analysis has proved invaluable in conclusively identifying micrometer sized boride precipitates; thus further improving the characterization of brazed Ni-based superalloys. - Highlights: • We attempt to accurately identify Boron-rich phases in Ni-based superalloys. • EDS, WDS, EBSD systems are tested for accurate identification of these borides. • Results are compared with those obtained by electron probe microanalysis. • Boron was measured with EDS by composition difference with a precision of 5 at. %. • Additional EBSD in phase identification mode conclusively identifies the borides

  3. Analysis on interfacial layer of aluminum alloy and non-coated stainless steel joint made by TIG welding-brazing

    Institute of Scientific and Technical Information of China (English)

    Song Jiaaling; Lin Sanbao; Yang Chunli; Ma Guangchao; Wang Yinjie

    2009-01-01

    Dissimilar metals TIG welding-brazing of aluminum alloy and non-coated stainless steel was investigated. The resultant joint was characterized in order to identify the phases and the brittle intermetaUic compounds (IMCs) in the interfacial layer by optical metalloscope (OM), wanning electron microscopy (SEM) and energy dispersive spectrometer (EDS), and the cracked joint was analyzed in order to understand the cracking mechanism of the joint. The results show that the microfusion of the stainless steel can improve the wetting and spreading of liquid aluminum base filler metal on the steel surface and the melted steel accelerates the formation of mass of brittle IMCs in the interracial layer, which causes the joint cracking badly. The whole interfacial layer is 5 - 7 μm thick and comprises approximately 5 μm-thickness reaction layer in aluminum side and about 2 μm-thickness diffusion layer in steel side. The stable Al-rich IMCs are formed in the interfaciallayer and the phases transfer from (Al + FeAl3) in aluminum side to (FeAl3+ Fe2Al5) and (α-Fe + FeAl) in steel side.

  4. Experimental study of W-Eurofer laser brazing for divertor application

    Energy Technology Data Exchange (ETDEWEB)

    Munez, C.J., E-mail: claudio.munez@urjc.es [Dept. de Tecnologia Mecanica, ESCET, Universidad Rey Juan Carlos, C/Tulipan s/n, Mostoles 28933, Madrid (Spain); Garrido, M.A. [Dept. de Tecnologia Mecanica, ESCET, Universidad Rey Juan Carlos, C/Tulipan s/n, Mostoles 28933, Madrid (Spain); Rams, J.; Urena, A. [Dept. de Ciencia e Ingenieria de Materiales, ESCET, Universidad Rey Juan Carlos, C/Tulipan s/n, Mostoles 28933, Madrid (Spain)

    2011-11-15

    Highlights: > Laser brazing system as a suitable technique to joint W and Eurofer alloys. > High residual stresses at the bonding were produced. > Laser brazing of powder metallurgy W alloys added porosity in the solidified pool. > The CSM methodology as a suitable technique to discriminate zones of welding joints. - Abstract: This work can be considered as a preliminary evaluation of the potential of laser brazing for joining tungsten based alloys to reduced activation ferritic-martensitic steels (Eurofer). Brazing of tungsten and EUROFER alloys using a 55Ni-45Ti alloy as a brazer and a high power diode laser (HPDL) as a power source has been investigated. The brazed joints showed solidified pools with good superficial aspect and a high degree of wettability with the both parent sheets, presumably because of the active effect of titanium. Metallurgical brazeability was investigated and nanoindentation measurements were done to evaluate local hardening and stiffness effects associated to dilution phenomena.

  5. Numerical Simulation on Joining of Ceramics with Metal by Friction Welding Technique

    Science.gov (United States)

    Jesudoss Hynes, N. Rajesh; Nagaraj, P.; Basil, S. Joshua

    The joining of ceramic and metals can be done by different techniques such as ultrasonic joining, brazing, transient liquid phase diffusion bonding, and friction welding. Friction Welding is a solid state joining process that generates heat through mechanical friction between a moving workpiece and a stationary component. In this article, numerical simulation on thermal analysis of friction welded ceramic/metal joint has been carried out by using Finite Element Analysis (FEA) software. The finite element analysis helps in better understanding of the friction welding process of joining ceramics with metals and it is important to calculate temperature and stress fields during the welding process. Based on the obtained temperature distribution the graphs were plotted between the lengths of the joint corresponding to the temperatures. To increase the wettability, aluminium sheet was used as an interlayer. Hence, numerical simulation of friction welding process is done by varying the interlayer sheet thickness. Transient thermal analysis had been carried out for each cases and temperature distribution was studied. From the simulation studies, it is found that the increase in interlayer thickness reduces the heat affected zone and eventually improves the joint efficiency of alumina/aluminum alloy joints.

  6. Advances in brazing science, technology and applications

    CERN Document Server

    2013-01-01

    Brazing processes offer enhanced control, adaptability and cost-efficiency in the joining of materials. Unsurprisingly, this has lead to great interest and investment in the area. Drawing on important research in the field, Advances in brazing provides a clear guide to the principles, materials, methods and key applications of brazing. Part one introduces the fundamentals of brazing, including molten metal wetting processes, strength and margins of safety of brazed joints, and modeling of associated physical phenomena. Part two goes on to consider specific materials, such as super alloys, filler metals for high temperature brazing, diamonds and cubic boron nitride, and varied ceramics and intermetallics. The brazing of carbon-carbon (C/C) composites to metals is also explored before applications of brazing and brazed materials are discussed in part three. Brazing of cutting materials, use of coating techniques, and metal-nonmetal brazing for electrical, packaging and structural applications are reviewed, alon...

  7. The quality evaluation of the end-plate welds and brazed joints for CANDU nuclear fuel by an ultrasonic imaging method

    International Nuclear Information System (INIS)

    This paper describes a method for the quality evaluation of spot welds and brazed joints by analysing ultrasonic images (C-scan). A present, the quality control for these joints is made by destructive methods. The authors present the most frequent types of flaw met in their investigations. They have attempted to obtain a dependence of torsion moment, measured by a destructive method against the polar inertia moment, obtained from parameters measured on ultrasound images. The ultrasonic images were analysed off-line using a dedicated software. (author)

  8. Vacuum Brazing of Accelerator Components

    International Nuclear Information System (INIS)

    Commonly used materials for accelerator components are those which are vacuum compatible and thermally conductive. Stainless steel, aluminum and copper are common among them. Stainless steel is a poor heat conductor and not very common in use where good thermal conductivity is required. Aluminum and copper and their alloys meet the above requirements and are frequently used for the above purpose. The accelerator components made of aluminum and its alloys using welding process have become a common practice now a days. It is mandatory to use copper and its other grades in RF devices required for accelerators. Beam line and Front End components of the accelerators are fabricated from stainless steel and OFHC copper. Fabrication of components made of copper using welding process is very difficult and in most of the cases it is impossible. Fabrication and joining in such cases is possible using brazing process especially under vacuum and inert gas atmosphere. Several accelerator components have been vacuum brazed for Indus projects at Raja Ramanna Centre for Advanced Technology (RRCAT), Indore using vacuum brazing facility available at RRCAT, Indore. This paper presents details regarding development of the above mentioned high value and strategic components/assemblies. It will include basics required for vacuum brazing, details of vacuum brazing facility, joint design, fixturing of the jobs, selection of filler alloys, optimization of brazing parameters so as to obtain high quality brazed joints, brief description of vacuum brazed accelerator components etc.

  9. 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…

  10. Optimal parameters determination of the orbital weld technique using microstructural and chemical properties of welded joint

    International Nuclear Information System (INIS)

    The paper deals with the study of the main parameters of thermal cycle in Orbital Automatic Weld, as a particular process of the GTAW Weld technique. Also is concerned with the investigation of microstructural and mechanical properties of welded joints made with Orbital Technique in SA 210 Steel, a particular alloy widely use during the construction of Economizers of Power Plants. A number of PC software were used in this sense in order to anticipate the main mechanical and structural characteristics of Weld metal and the Heat Affected Zone (HAZ). The papers also might be of great value during selection of optimal Weld parameters to produce sound and high quality Welds during the construction / assembling of structural components in high requirements industrial sectors and also to make a reliable prediction of weld properties

  11. RFQ Vacuum brazing at CERN

    CERN Document Server

    Mathot, S

    2008-01-01

    The aim of this paper is to describe the vacuum brazing procedure used at CERN for the brazing of Radio Frequency Quadrupole (RFQ). The RFQ is made of high precision machined OFE copper pieces assembled together. Vacuum brazing is one of the most promising techniques used to join the individual components leading to vacuum tightness and high precision alignment. The RFQ modules brazed at CERN are made of four 100 or 120 cm long vanes (two major and two minor vanes). Our brazing procedure consists of two steps. The first step involves the brazing of the four vanes in a horizontal position. The second step consists of brazing the vacuum stainless steel flanges to the copper structure in a vertical position. The paper describes the problems encountered with the alignment and the vacuum tightness. The difficulties related to the stress relaxation of the machined copper pieces during the brazing heat treatment are discussed. In addition, the solutions developed to improve the alignment of the brazed RFQ’s are...

  12. Laser Brazing of High Temperature Braze Alloy

    Science.gov (United States)

    Gao, Y. P.; Seaman, R. F.; McQuillan, T. J.; Martiens, R. F.

    2000-01-01

    The Space Shuttle Main Engine (SSME) consists of 1080 conical tubes, which are furnace brazed themselves, manifolds, and surrounding structural jacket making almost four miles of braze joints. Subsequent furnace braze cycles are performed due to localized braze voids between the coolant tubes. SSME nozzle experiences extremely high heat flux (180 mW/sq m) during hot fire. Braze voids between coolant tubes may result in hot combustion gas escape causing jacket bulges. The nozzle can be disqualified for flight or result in mission failure if the braze voids exceed the limits. Localized braze processes were considered to eliminate braze voids, however, damage to the parent materials often prohibited use of such process. Being the only manned flight reusable rocket engine, it has stringent requirement on the braze process. Poor braze quality or damage to the parent materials limits the nozzle service life. The objective of this study was to develop a laser brazing process to provide quality, localized braze joints without adverse affect on the parent materials. Gold (Au-Cu-Ni-Pd-Mn) based high temperature braze alloys were used in both powder and wire form. Thin section iron base superalloy A286 tube was used as substrate materials. Different Laser Systems including CO2 (10.6 micrometers, 1kW), ND:YAG (1.06 micrometers, 4kW). and direct diode laser (808nm. 150W) were investigated for brazing process. The laser process variables including wavelength. laser power, travel speed and angle of inclination were optimized according to bead geometry and braze alloy wetting at minimum heat input level, The properties of laser brazing were compared to that of furnace brazing. Microhardness profiles were used for braze joint property comparison between laser and furnace brazing. The cooling rate of laser brazing was compared to furnace brazing based on secondary dendritic arm spacing, Both optical and Scanning Electron Microscope (SEM) were used to evaluate the microstructures of

  13. Development of laser welded appendages to Zircaloy-4 fuel tubing (sheath/cladding)

    International Nuclear Information System (INIS)

    Highlights: • Examines feasibility of laser welding appendages to Zr-4 tubing. • Laser welding minimizes the HAZ and removes toxic Be. • Mechanical properties of laser welds appear competitive with induction brazed joints. • Work appears promising and lays the foundation for further investigations. - Abstract: Laser welding is a potential alternative to the induction brazing process commonly used for appendage attachment in CANDU® fuel fabrication that uses toxic Be as a filler metal, and creates multiple large heat affected zones in the sheath. For this work, several appendages were laser welded to tubing using different laser heat input settings and then examined with a variety of techniques: visual examination, metallography, shear strength testing, impact testing, and fracture surface analysis. Where possible, the examination results are contrasted against production induction brazed joints. The work to date looks promising for laser welded appendages. Further work on joint optimization, corrosion testing, irradiation testing, and post-irradiation examination will be performed in the future

  14. 镁/镀锌钢异种合金单、双光束激光熔钎焊特性%Single and dual beam laser welding-brazing characteristics of magnesium/zinc-coated steel dissimilar alloys

    Institute of Scientific and Technical Information of China (English)

    檀财旺; 梅长兴; 李俐群; 戴景民; 郭伟

    2012-01-01

    以镁焊丝为填充材料,对镁/镀锌钢异种合金进行单、双光束激光熔钎焊试验研究,分析不同工艺参数对焊缝成形的影响规律,获得不同热源作用方式下的界面形态规律及其对界面强度的影响.结果表明:采用单、双光束进行填丝熔钎焊均可获得较满意的外观成形:单光束容易存在未钎合现象,焊接过程不够稳定,而双光束具有更好的温度分布,容易提高润湿铺展能力.剪切强度测试结果表明,单、双光束最大的接头效率分别达到30.9%和42.4%,焊趾处裂纹的存在是导致接头失效的主要原因.%The single and dual laser welding-brazing of AZ31 Mg alloy to DP980 galvanized steel was conducted with Mg filler wire. The effect of different parameters on the weld appearance was analyzed. Moreover, the interfacial pattern under different heat sources and its influence on the interfacial strength were obtained. The results indicate that good weld appearance can be achieved using both single and dual laser beam welding-brazing as filler wire. It tends to produce the lack of fusion defect by single-beam welding and the welding process is unstable. The dual-beam welding has much more uniform temperature distribution, so, the spreading-wetting ability is better than the former. The shear test results show that the highest joint efficiency of single-beam and dual-beam welding are 30.9% and 42.4%, respectively. The crack produced at the toe of weld after laser welding-brazing is the main reason for joint failure.

  15. Infrared sensing techniques for adaptive robotic welding

    International Nuclear Information System (INIS)

    The objective of this research is to investigate the feasibility of using infrared sensors to monitor the welding process. Data were gathered using an infrared camera which was trained on the molten metal pool during the welding operation. Several types of process perturbations which result in weld defects were then intentionally induced and the resulting thermal images monitored. Gas tungsten arc using ac and dc currents and gas metal arc welding processes were investigated using steel, aluminum and stainless steel plate materials. The thermal images obtained in the three materials and different welding processes revealed nearly identical patterns for the same induced process perturbation. Based upon these results, infrared thermography is a method which may be very applicable to automation of the welding process

  16. New techniques in the welding of spherical reactor containments

    International Nuclear Information System (INIS)

    An account is given of the developments if mechanical welding techniques in reactor containment construction. The developments were aimed at improving the technical quality of welds, their reliability with regard to porosity and crack formation, and at reducing the impact of human factors. The contribution particularly discusses the welding of sheet metals in preparatory assembly work using two tandem submerged-arc welding machines working in parallel, and the tandem electrode submerged-arc welding of circumferential weld seams. The material under investigation is the normalized fine-grained steel 15MnNi63 (38 mm thick) with 370 N/mm2 minimum yield point, which has first been used in the construction of Philipsburg nuclear power plant. (orig.)

  17. Induction brazing manual

    Science.gov (United States)

    1971-01-01

    Manual presents standards and techniques which are known or are particular to specific industry, and is useful as guide in closing tolerance brazing. Material and equipment specifications, tool setting tables, and quality control data and instructions are included. Since similar standards are available, manual is supplementary reference.

  18. Induction Brazing

    DEFF Research Database (Denmark)

    Henningsen, Poul

    Induction brazing is a fast and appropriate method for industrial joining of complex geometries and metal combinations. In all types of brazing processes it is important to heat the joint interface of the two materials to the same, high temperature. If one of the specimens is warmer than the other...... materials has large influence on the heating time and temperature distribution in induction heating. In order to ensure high and uniform temperature distribution near the interface of a joint between dissimilar materials the precise coil geometry and position is of great importance. The present report...... presents a combined numerical and experimental method for determination of appropriate/optimiged coil geometry and position in induction brazing tube-to-plate joints of different ratios between tube and plate thickness and different combinations of the materials stainless steel, brass and copper...

  19. Development of Welding Technique for Double Wall Tube

    International Nuclear Information System (INIS)

    A helical-coil-type double wall tube with wire mesh interlayer, is proposed for a steam generator of the new-type small reactor 4S. The 4S, Super-Safe, Small and Simple is a small-sized sodium cooled fast reactor. It is necessary to make a tube-to-tube joint of an independent inner-to-inner and outer-to-outer way without bonding inner and outer walls. So we have been developing the welding techniques to satisfy this requirement. A keyhole type laser welding technique was selected and a small laser welding head, which can weld from the inside the inner tube, was developed. Using this welding head, welding conditions, such as welding speed and laser power were surveyed. As a result of the test, the welding condition, which did not make the inner and outer tubes bonding, was obtained. There was no non-adequate phase change. Tensile strength was satisfied the specification for the base metal. (author)

  20. The use of a video camera in welding. Welding technique to limit the hardness under bead

    International Nuclear Information System (INIS)

    In the nuclear maintenance, the repair or modification works on activated loops or components generally cause problems with the permissible dose for the highly qualified welding operators who have to do these jobs. In order to find a solution of these problems, we are concerned with a great number of such problems, so that we have developed, adapted and applied welding techniques by using a video-camera for remote control. The lecture deals with the following subjects: specific problems of this application, human factors to be considered, and an application example: description of the operation, employed equipment, avoidable dose. In the nuclear maintenance, the repair works by welding are often necessary. When these operations are made on so-called 'black' steel quality, generally the question of stress relieving arises. In fact, if this relieving is justified from the metallurgical point of view, this causes important difficulties in its application and very often produces considerable thermal stressing which are difficult to determine. In order to find a solution of these problems, we have developed and obtained the authorization for welding techniques to limit the hardness under bead, which allows to do repairs by welding without stress relieving. The lecture deals with the following subjects: technical explanation of the welding techniques for limited hardness by welding without stress relieving, specific problems of this application and application examples: description of the operation, process authorization, employed equipment. (orig.)

  1. Brazing of sensors for high-temperature steam instrumentation systems

    International Nuclear Information System (INIS)

    Procedures are developed for brazing a ceramic-to-metal seal and for laser welding of sensor subassemblies into tube walls, induction brazing thermocouples through a tube wall, and furnace brazing triaxial cables, thermocouples, and a vent tube to a guide tube study three-dimensional phenomena in the upper plenum and core of a pressurized water reactor during the reflood stage of a loss-of-coolant accident. 8 refs

  2. Review on Lossless Image Compression Techniques for Welding Radiographic Images

    Directory of Open Access Journals (Sweden)

    B. Karthikeyan

    2013-01-01

    Full Text Available Recent development in image processing allows us to apply it in different domains. Radiography image of weld joint is one area where image processing techniques can be applied. It can be used to identify the quality of the weld joint. For this the image has to be stored and processed later in the labs. In order to optimize the use of disk space compression is required. The aim of this study is to find a suitable and efficient lossless compression technique for radiographic weld images. Image compression is a technique by which the amount of data required to represent information is reduced. Hence image compression is effectively carried out by removing the redundant data. This study compares different ways of compressing the radiography images using combinations of different lossless compression techniques like RLE, Huffman.

  3. Achieving cost savings with innovative welding and examination techniques

    International Nuclear Information System (INIS)

    In an effort to maximize quality and production in both field and shop fabrication while minimizing cost, Fluor has assessed new and innovative welding and examination technologies. Welding applications, power sources, arc transfer modes, and shielding gas mixtures using various semi-automatic processes were compared. The strategies for the selection of these welding variables, as well as the successful application of a modified short-circuiting gas metal arc welding process to carbon, alloy, and stainless steels are discussed. The optimized process combination can achieve three times the deposition rate and one-tenth of the repair rate commonly obtained with traditional processes. In weldment examinations, a modified phased array ultrasonic technique is presented. As an alternate for radiography, phased array technology allows for 10 times lower inspection times and lends itself to an ideal weld-and-check methodology. Additional cost savings and further, productivity improvements have been achieved by combining these novel welding and examination techniques. This technology has demonstrated itself with a supporting track record on several major construction projects in North America

  4. Laser Welding and Syncristallization Techniques Comparison: In Vitro Study

    Directory of Open Access Journals (Sweden)

    C. Fornaini

    2012-01-01

    Full Text Available Background. Laser welding was first reported in 1967 and for many years it has been used in dental laboratories with several advantages versus the conventional technique. Authors described, in previous works, the possibility of using also chair-side Nd : YAG laser device (Fotona Fidelis III, =1064 nm for welding metallic parts of prosthetic appliances directly in the dental office, extra- and also intra-orally. Syncristallisation is a soldering technique based on the creation of an electric arc between two electrodes and used to connect implants to bars intra-orally. Aim. The aim of this study was to compare two different laser welding devices with a soldering machine, all of these used in prosthetic dentistry. Material and Methods. In-lab Nd : YAG laser welding (group A = 12 samples, chair-side Nd : YAG laser welding (group B = 12 samples, and electrowelder (group C = 12 samples were used. The tests were performed on 36 CrCoMo plates and the analysis consisted in evaluation, by microscopic observation, of the number of fissures in welded areas of groups A and B and in measurement of the welding strength in all the groups. The results were statistically analysed by means of one-way ANOVA and Tukey-Kramer multiple comparison tests. Results. The means and standard deviations for the number of fissures in welded areas were 8.12±2.59 for group A and 5.20±1.38 for group B. The difference was statistical significant (=0.0023 at the level 95%. On the other hand, the means and standard deviations for the traction tests were 1185.50±288.56 N for group A, 896.41±120.84 N for group B, and 283.58±84.98 N for group C. The difference was statistical significant (=0.01 at the level 95%. Conclusion. The joint obtained by welding devices had a significant higher strength compared with that obtained by the electrowelder, and the comparison between the two laser devices used demonstrated that the chair-side Nd : YAG, even giving a

  5. Laser welding and syncristallization techniques comparison: in vitro study.

    Science.gov (United States)

    Fornaini, C; Merigo, E; Vescovi, P; Meleti, M; Nammour, S

    2012-01-01

    Background. Laser welding was first reported in 1967 and for many years it has been used in dental laboratories with several advantages versus the conventional technique. Authors described, in previous works, the possibility of using also chair-side Nd : YAG laser device (Fotona Fidelis III, λ = 1064 nm) for welding metallic parts of prosthetic appliances directly in the dental office, extra- and also intra-orally. Syncristallisation is a soldering technique based on the creation of an electric arc between two electrodes and used to connect implants to bars intra-orally. Aim. The aim of this study was to compare two different laser welding devices with a soldering machine, all of these used in prosthetic dentistry. Material and Methods. In-lab Nd : YAG laser welding (group A = 12 samples), chair-side Nd : YAG laser welding (group B = 12 samples), and electrowelder (group C = 12 samples) were used. The tests were performed on 36 CrCoMo plates and the analysis consisted in evaluation, by microscopic observation, of the number of fissures in welded areas of groups A and B and in measurement of the welding strength in all the groups. The results were statistically analysed by means of one-way ANOVA and Tukey-Kramer multiple comparison tests. Results. The means and standard deviations for the number of fissures in welded areas were 8.12 ± 2.59 for group A and 5.20 ± 1.38 for group B. The difference was statistical significant (P = 0.0023 at the level 95%). On the other hand, the means and standard deviations for the traction tests were 1185.50 ± 288.56 N for group A, 896.41 ± 120.84 N for group B, and 283.58 ± 84.98 N for group C. The difference was statistical significant (P = 0.01 at the level 95%). Conclusion. The joint obtained by welding devices had a significant higher strength compared with that obtained by the electrowelder, and the comparison between the two laser devices used demonstrated that the chair-side Nd : YAG, even giving

  6. Fluxless Joining between Aluminium Alloy and Galvanized Steel by Fiber Laser Fusion Welding-Brazing with Filler Powder%铝/钢异种金属无钎剂激光填粉熔钎焊接

    Institute of Scientific and Technical Information of China (English)

    赵旭东; 肖荣诗

    2012-01-01

    The fluxless fusion welding-brazing result between 6061 aluminum alloy and galvanized steel with filler material is studied by using rectangular laser beam. The dependence of the mechanical properties on solidification behavior is established based on the joint formation and the weld microstructure. The results indicate that a fusion welding-brazing weld of AA6061 and galvanized steel without flux can be achieved using the welding with filler powder. By optimizing the welding parameters, the favorable weld without crack and porosity can be achieved. The weld width and the thickness of intermetallic compounds layer increase with laser energy input increasing. The intermetallic in the weld is composed of Al-Fe and Al-Fe-Si system phases. Specimens are fractured at the weld/steel interface with the brittle characteristic during tensile test. The weakness of the joint is the weld interface. The maximum intensity of 152. 5 N/mm is obtained. Al6Fe2Zn0.4 and α-Al are found in the fracture surface on the aluminum side. The intensity of joint is both determined by weld width and the thickness of intermetallic compound layer.%采用宽带激光光斑和填粉焊接技术,在不使用钎剂的情况下进行6061铝合金/镀锌钢板的熔钎焊接实验.分析测试了接头成形、焊缝组织和接头强度,并探讨了影响接头强度的因素.结果表明,采用此方法可实现6061铝合金/镀锌钢板的熔钎焊连接.选用优化的焊接工艺参数获得了成形饱满,无裂纹、气孔等缺陷的焊缝.焊缝熔宽和金属间化合物层厚度随焊接热输入量的增加而增大.熔钎焊缝中金属间化合物由AFFe和Al-Fe-Si系统化合物组成.拉伸试样均断裂在钎料/镀锌钢界面,接头最大机械抗力为152.5 N/mm,断口呈脆性断裂特征,钎料/镀锌钢界面为接头的薄弱环节.拉伸试样铝一侧断裂面由Al5 Fe2 Zno.4和α-Al组成.焊缝熔宽、金属间化合物层厚度共同决定了接头的机械抗力水平.

  7. Study on Influence Factors of Transient Behavior of Laser Brazing Weld Pool of Beryllium%铍材钎焊熔池动态行为的影响因素研究

    Institute of Scientific and Technical Information of China (English)

    史平安; 赵朋成; 莫军; 武传松; 郝志明

    2011-01-01

    With considering the geometry characteristic of laser brazing and analyzing the action features of heat source in laser brazing, a transient three-dimensional model of laser welding-brazing weld pool for beryllium is established on the basis of theories of fluid dynamics and heat transfer, in which a composite heat source constituted by double-ellipsoidal area heat source and Rotary-Gaussian body heat source along the z-direction is used to describe the heat flux source of a moving laser. Many factors are considered in the model including the convective heat transfer of liquid metal, solid heat conduction of workpiece outside the weld pool, latent heat in welding process, side assist gas orientation, the structure and properties of bonding interface, material thermo-physical properties as the function of temperature and so on. The program to simulate the transient variations of temperature field and flow field in laser brazing weld pool is developed by using Fortran language, and the effects of latent heat, the pattern of side assist gas and butt gap on fluid flow and heat transfer of weld pool are studied. The results show that the effects of the latent heat of phase change are not always negligible. In particular, the influence of the latent heat is more violent under moving laser beam action than under stationary laser beam. The gas flow rate and direction has an important effect on flow style and shape of weld pool, and the selection of side assist gas orientation can enhance the stability of laser brazing process and increase the depth of weld pool. The existence of gap makes the temperature field uneven and it is the decisive reason that the shape of weld pool looks like a nailhead. If the gap is taken into account, the shape of weld pool obtained from calculation will be in better agreement with the test result.%在综合分析激光钎焊的焊缝形状特征和热源作用特点的基础上,根据流体力学和传热学原理,建立瞬态熔池三维数

  8. 78 FR 75947 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Welding...

    Science.gov (United States)

    2013-12-13

    ...; Welding, Cutting, and Brazing Standard ACTION: Notice. SUMMARY: The Department of Labor (DOL) is... (ICR) titled, ``Welding, Cutting, and Brazing Standard,'' to the Office of Management and Budget (OMB... the Welding, Cutting, and Brazing Standard, regulations 29 CFR part 1910, subpart Q. More...

  9. Laser transmission welding of Clearweld-coated polyethylene glycol terephthalate by incremental scanning technique

    Science.gov (United States)

    Wang, Y. Y.; Wang, A. H.; Weng, Z. K.; Xia, H. B.

    2016-06-01

    Transmission laser welding using Incremental Scanning Technique(TWIST) mode and conventional contour welding mode were adopted to investigate laser transmission welding of 0.5 mm thick PET plate. A 1064 nm fiber laser was used to weld PET at the (TWIST) mode, and an 808 nm diode laser was applied to conduct the conventional contour welding. The Clearweld coating was used as laser absorbing material. The influences of laser parameters (i.e. defocusing distance, distance between two circles) on the quality of weld seams were analyzed by optical microscopy. Moreover, geometry and shear strength of the weld zone were tested to optimize laser parameters. Additionally, the water vapor permeability (WVP) of weld seams was measured to test hermetical capacity. Results show that the shear strength and hermetic capacity of weld seam by TWIST mode are at the same level in comparison with that of the conventional contour welding.

  10. AZ31B镁合金/不锈钢异种合金双光束激光熔钎焊接特性%Welding Characteristics of AZ31B Magnesium Alloy/Stainless Steel Dissimilar Alloys by Dual Beam Laser Welding-Brazing Process

    Institute of Scientific and Technical Information of China (English)

    李俐群; 郭伟; 檀财旺

    2012-01-01

    以镁基焊丝为填充材料,采用双光束激光熔钎焊的方法对AZ31B镁合金/不锈钢的焊接特性进行了研究.分析了不同工艺参数对焊缝成形、接头力学性能和断裂行为的影响.结果表明,采用双光束进行填丝熔钎焊能够获得较满意的外观成形,无明显缺陷,焊接工艺范围较宽.接头拉伸均断裂于熔化焊的镁侧焊缝及热影响区(HAZ),最大剪切强度为193 MPa,达到镁合金母材强度的71%.组织分析发现焊缝和HAZ的晶粒粗大,成为接头的薄弱部位,是接头失效的主要原因.钎焊侧界面发生了冶金反应,界面处生成1~2 μm的反应层.%AZ31B magnesium alloys and 201 stainless steel are joined by laser welding-brazing process with Mg based filler. The welding characteristics including influence of processing parameters on weld appearance, mechanical properties and fracture behavior are studied- Results indicate that satisfactory appearance of welds without evident defects can be achieved by dual beam laser-brazing process with filler. A wide processing window is obtained. The tensile-shear test shows that fracture occurred at two places, weld seam and heat affect zone (HAZ) at the welding side of Mg alloys. The maximum shear strength can reach 193 Mpa, which is 71% of that of Mg base metal. The microstructure observed indicates that seam and HAZ are weak parts, which results in failure of joint due to presence of coarse grains. Metallurgical reaction occurs at the brazing side, where reaction layer with thickness of 1~2 μm forms.

  11. Expulsion characterization in resistance spot welding by means of a hardness mapping technique

    Institute of Scientific and Technical Information of China (English)

    H.Ghazanfari; M.Naderi

    2014-01-01

    Expulsion is an undesired event during resistance spot welding because the weld quality deteriorates. It is the ejection of molten metal from the weld nugget which usually occurs due to applying a high current for a short welding time. Expulsion has a significant impact on the final yield strength of the weld, thus the detection and characterization of expulsion events is significant for the quality assurance of resistance spot welds. In this study, hardness mapping, using a scanning hardness machine, was used as a quality assurance technique for re-sistance spot welding. Hardness tests were conducted on a resistance spot welded sample to prepare a hardness map. The test results showed good correlation between the hardness map and metallographic cross sections. The technique also provided further fundamental understand-ing of the resistance spot welding process, especially regarding the occurrence of expulsion in the nugget.

  12. Microstructural examination of Zr-2.5%Nb alloy welds made by pulsed Nd:YAG laser and TIG welding technique

    International Nuclear Information System (INIS)

    The paper describes the weld microstructure of Zr-2.5%Nb alloy material. Bead on plate welds were made using pulsed Nd:YAG laser and TIG welding technique at different parameters. These welds were characterized at macro and microstructural level. Weld pools of Pulsed Laser and TIG welds were not resolved by optical microscopy. SEM too did not reveal much. Orientation imaging microscopy could reveal the presence of fine martensite. It was observed that microstructure is very sensitive to welding parameters. Microhardness studies suggested formation of martensite in the weld pool. It was also observed that laser welds had very sharp weld pool boundary as compared to TIG welds. Variation in microhardness of the weldment is seen and is influenced by overlapping of weld spots causing thermal treatment of previously deposited spots. (author)

  13. 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.

  14. Influence of brazing parameters and alloy composition on interface morphology of brazed diamond

    Energy Technology Data Exchange (ETDEWEB)

    Klotz, Ulrich E. [Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Joining and Interface Technology, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland)], E-mail: klotz@fem-online.de; Liu Chunlei [Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Joining and Interface Technology, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland); Khalid, Fazal A. [Faculty of Metallurgy and Materials Engineering, GIK Institute, Topi, NWFP (Pakistan); Elsener, Hans-Rudolf [Empa, Swiss Federal Laboratories for Materials Testing and Research, Laboratory for Joining and Interface Technology, Uberlandstrasse 129, CH-8600 Duebendorf (Switzerland)

    2008-11-15

    Active brazing is an effective technique for joining diamond or cBN grit to metallic substrates. This technique is currently used to manufacture superabrasive, high-performance tools. The investigation of interface reactions between diamond and active brazing alloys plays an important role in understanding and improving the brazing process and the resultant tool performance. Focused ion beam (FIB) milling enabled the high resolution investigation of these extremely difficult to prepare metal-diamond joints. The interfacial nanostructure is characterized by the formation of two layers of TiC with different morphologies. First a cuboidal layer forms directly on the diamond and reaches a thickness of approximately 70 nm. Then a second layer with columnar TiC crystals grows on the first layer into the brazing filler metal by a diffusion-controlled process. The combined thickness of both TiC layers varies between 50 nm and 600 nm depending on the brazing temperature and holding time.

  15. Influence of brazing parameters and alloy composition on interface morphology of brazed diamond

    International Nuclear Information System (INIS)

    Active brazing is an effective technique for joining diamond or cBN grit to metallic substrates. This technique is currently used to manufacture superabrasive, high-performance tools. The investigation of interface reactions between diamond and active brazing alloys plays an important role in understanding and improving the brazing process and the resultant tool performance. Focused ion beam (FIB) milling enabled the high resolution investigation of these extremely difficult to prepare metal-diamond joints. The interfacial nanostructure is characterized by the formation of two layers of TiC with different morphologies. First a cuboidal layer forms directly on the diamond and reaches a thickness of approximately 70 nm. Then a second layer with columnar TiC crystals grows on the first layer into the brazing filler metal by a diffusion-controlled process. The combined thickness of both TiC layers varies between 50 nm and 600 nm depending on the brazing temperature and holding time

  16. Development of magnetographic technique for inspecting containment welds through coatings

    International Nuclear Information System (INIS)

    The magnetographic technique was investigated for NDE of containment welds without removing paint. This technique used a magnetic yoke to magnetize a localized region of the steel containment; the leakage field from a flaw was transferred to magnetic tape placed on the containment surface and subsequently read either by means of a magnetic field sensor scanned over the tape or by the visual indications on the tape. Four specimen configurations were fabricated for the experimental evaluations. The first, a flat-plate specimen containing electric discharge machined (EDM) notches, was fabricated for initial evaluations. The three others that contained cracks consisted of one welded flat plate and two simulated containment structures representing, respectively, the longitudinal and circumferential welds in the containment wall and the 90 degree angle encountered at the base of the containment and penetrations. During the project, two types of tape were investigated, magnetic recording and Magnafilm, a tape-like material designed to produce a permanent visual indication of the magnetic leakage field from a flaw. The results show that although the magnetic recording tape did not provide sufficient sensitivity, an inspection using Magnafilm visual indications appears suitable. The latter can reliably detect containment weld cracks 6mm long through paint thicknesses up to 0.23mm and cracks longer than 6mm through paint thicknesses up to 0.38mm. Detection of cracks 6mm long through paint 0.38mm thick can be achieved by scanning the Magnafilm with a magnetic tape head; however, this approach will also tend to produce more false indications

  17. Laser welding-brazing and numerical simulation of zinc-coated steel and 6016 aluminum alloy%镀Zn钢-6016铝合金异种金属的激光熔钎焊及数值模拟

    Institute of Scientific and Technical Information of China (English)

    周惦武; 吴平; 彭利; 张屹; 陈根余

    2012-01-01

    熔钎焊是抑制或减少钢/铝异种金属激光焊接过程中FeAl脆性金属间化合物产生的有效工艺方法.采用光纤激光器,不添加任何钎料,对1.2 mm厚DC56D+ZF镀锌钢和6016铝合金平板试件进行激光搭接焊试验,利用MATLAB软件,针对焊接过程的实际情况,在一定的基本假设下建立准稳态下钢/铝异种金属激光焊接熔池形状的数学模型,基于准稳态形状控制方程数值计算获得的熔池几何形状分布,结合试验来调整焊接工艺参数,获得最佳焊接成形,利用卧式金相显微镜、扫描电镜和X射线衍射仪等手段研究焊接接头各区域的金相组织、主要元素分布与物相组成.结果表明:焊接激光束照射搭接在钢板上的铝板对接焊缝时,焊接功率和焊接速度对熔池几何形状的影响较大,随着激光功率的增大,熔深增加;而随着焊接速度的增加,熔深却变浅.当焊接功率为1 600~1 800W、焊接速度v=30 mm/s、离焦量D=0 mm时,焊缝成形性良好,无明显裂纹、气孔等缺陷,焊接接头区域存在一个台阶状结构,在平台区域,钢/铝两钟金属存在明显的界限,界面结合依靠液态的铝在钢母材表面上的润湿、填充和铺展等作用;下凹区域,钢/铝熔合较好,Fe和Al元素的混合区宽度较大,未形成明显的FeAl脆性金属间化合物,Fe和Al的热扩散是该区域界面结合的主要原因.%The laser welding-brazing is an effective process to inhibit or reduce FeAl brittle intermetallic compound produced during laser welding-brazing of steel and aluminum alloy. The laser lap welding test was carried out based on the DC56D+ZF galvanized steel with thickness of 1.2 mm and the 6016 aluminum alloy with the fiber laser. The Matlab software was used, according to the actual situation of welding process, the steel and aluminum dissimilar metal laser welding pool shapes of the mathematical model in the flight quasi-steady state was established under

  18. Development of technique for laser welding of biological tissues using laser welding device and nanocomposite solder.

    Science.gov (United States)

    Gerasimenko, A; Ichcitidze, L; Podgaetsky, V; Ryabkin, D; Pyankov, E; Saveliev, M; Selishchev, S

    2015-08-01

    The laser device for welding of biological tissues has been developed involving quality control and temperature stabilization of weld seam. Laser nanocomposite solder applied onto a wound to be weld has been used. Physicochemical properties of the nanocomposite solder have been elucidated. The nature of the tissue-organizing nanoscaffold has been analyzed at the site of biotissue welding. PMID:26738200

  19. Sensors Array Technique for Monitoring Aluminum Alloy Spot Welding

    Institute of Scientific and Technical Information of China (English)

    王蕤; 罗震; 单平; 步贤政; 袁书现; 敖三三

    2010-01-01

    In this paper,the sensors array technique is applied to the quality detection of aluminum alloy spot welding.The sensors array has three forms,i.e.,linear magnetic sensors array,annular magnetic sensors array and cross magnetic sensors array.An algorithm based on principal component analysis is proposed to extract the signal eigenvalues.The three types of magnetic sensors array are used in the experiment of monitoring the signal.After the eigenvalues are extracted,they are used to build a relationship with ...

  20. Ultrasonic weld defect sizing using the synthetic aperture focusing technique

    International Nuclear Information System (INIS)

    The synthetic aperture focusing technique (SAFT) has been shown to increase lateral resolution of appropriately acquired B-scan images. The requirements of very accurate transducer position information and a well understood divergent ultrasonic beam can make it difficult to incorporate the technique into conventional inspections or to use it on previously acquired data. By using a reference reflector and an echo locus matching procedure it is possible to ease the latter requirement so that data acquired using conventional focused or flat transducers can be enhanced using the SAFT process. One current application of the SAFT technique is the accurate sizing and monitoring of known defects in a nuclear generating station boiler manway weld. Testing on laboratory samples which duplicate the manway geometry indicate the potential for improved resolution using SAFT

  1. Welding technique research between fuel element Zr-4 end and tantalum tube and its application

    International Nuclear Information System (INIS)

    The author introduces welding technique between fuel element cladding Zr-4 end and tantalum tube which is used to introduce the W/Re thermocouple and water pressure test and corrosion test of the weld. The results show that the welded surface takes form better, lacks metallurgical defect and the weld causes no leakage under 9.0 MPa pressure. There is the corrosion phenomenon in the weld after heating at 450 degree C for 100 h in melting PbBi alloy, but it can retard the corrosion in PbBi alloy after preoxidation film treatment. The adopted measures has been proposed in the design and assemble of irradiation capsule

  2. Ultrasonic examination of stainless steel EB welds by an immersion technique

    International Nuclear Information System (INIS)

    The authors report the development of an ultrasonic examination method of austenitic stainless steel electron beam (EB) welds. This method is based on an automatic immersion technique employing focused transducers and is aimed at detecting both the weld soundness and penetration. The authors describe the examination procedure with a calibration of the ultrasonic equipment, a complete weld scanning, and a repetition of the calibration for matters of verification. They also describe how results are interpreted in terms of wave soundness (attenuation) and weld penetration. They discuss the reliability of the examination procedure. They comment results obtained for EB butt welds in a AISI 304 pipe

  3. Ultrasonic testing of austenitic and austenitic-ferritic welds made possible by NDT-based optimization of welding techniques, illustrated for some circumferential pipe welds at NPP components, and their qualification

    International Nuclear Information System (INIS)

    The paper summarizes practical results of the making and testing of austenitic and austenitic-ferritic welds in compliance with the KTA codes. The subsequent evaluation is based on mechanized ultrasonic testing for longitudinal flaws in pipe welds made by narrow-gap TIG welding. It is shown that NDT of austenitic as well as austenitic-ferritic root welds produced after optimization of welding techniques can be done with shear wave transducers, and yields satisfactory results. (orig./CB)

  4. Development of multifunction laser welding head (3). Surface inspection technique by laser-ultrasonics

    International Nuclear Information System (INIS)

    Multifunction laser welding head has been developed. The head is able to perform not only underwater laser welding as repair, but also laser peening as preventive maintenance and laser ultrasonic testing as inspection. For inspection with multifunction laser welding head, a new method of visualized weld defects in water by laser-ultrasonics has developed. To detect and visualize a surface of weld metal with welding bead, the authors have developed a new detection method by leaky wave induced by interaction with surface acoustic waves and defects. Furthermore, developing Synthetic Aperture Focus Technique (SAFT) for visualized inspection surface 2-dimensionally, we achieve the inspection result alike Penetrant Testing (PT) despite underwater environment with multifunction laser welding head. (author)

  5. Multiple-unit implant frames: one-piece casting vs. laser welding and brazing Sobre estruturas de implantes múltiplos: fundição em monobloco versus soldagem a laser e brasagem

    Directory of Open Access Journals (Sweden)

    Elza Maria Valadares da Costa

    2004-09-01

    Full Text Available The linear distortion of prostheses over implants, one-piece casting and cast in sections followed by laser welding by laser and brazing was evaluated in an edentulous mandibular model with five parallel abutments, with a distance of 10mm from center to center. Seventy five gold cylinders were tightened with screws on the abutments with 10Ncm torque. The cylinder/analogue assemblies were measured by microscopic examination (0.001mm accuracy and the obtained results were compared with the GC (control group. Fifteen metal frames were waxed and cast in a gold alloy (Stabilor, Degussa Hulls, Brazil and divided into three groups with five elements each, as followed: GM (one-piece casting, GB (section and brazing and GL (section and laser welding. In all groups, measurements were taken at the right, left, buccal and lingual sides of the cylinder/analogue interface and the results were submitted to analysis of variance (ANOVA and to the Tukey test (5%. The smallest amount of distortion was seen in the laser group (GL with a mean value of 13.58, followed by the brazing group (GB with a mean value of 24.33 and one-piece (GM with a mean value of 40.00. The greatest distortion was found in the one-piece group (GM.A distorção linear das próteses sobre implantes, fundidas em monobloco e fundidas em secções e soldadas a laser e por brasagem foi avaliada em um modelo de uma mandíbula edêntula com cinco análogos de pilares de implantes, paralelos entre si com distância de 10mm medidos de centro a centro. Sobre estes foram parafusados novos cilindros de ouro, com torque de 10N/cm. Então foram executadas 15 sobre-estruturas metálicas que foram divididas: GC - Adaptação passiva dos cilindros de ouro; GM - monobloco, GB - segmentos soldados por brasagem e, GL - segmentos soldados a laser. Observaram-se as estruturas fixadas com parafusos novos sob microscópio de mensuração. A medição foi realizada na vestibular direita e esquerda e da mesma forma

  6. Sensors Array Technique for Monitoring Aluminum Alloy Spot Welding

    Institute of Scientific and Technical Information of China (English)

    WANG Rui; LUO Zhen; SHAN Ping; BU Xianzheng; YUAN Shuxian; AO Sansan

    2010-01-01

    In this paper, the sensors array technique is applied to the quality detection of aluminum alloy spot weld-ing. The sensors array has three forms, i.e., linear magnetic sensors array, annular magnetic sensors array and cross magnetic sensors array. An algorithm based on principal component analysis is proposed to extract the signal eigen-values. The three types of magnetic sensors array are used in the experiment of monitoring the signal. After the eigen-values are extracted, they are used to build a relationship with the nugget information. The result shows that when the distance between the core of the array and the pole is 60 mm, the arrays work best. In this case, when the eigenvalues' range of the linear array is 0.006 5-0.015 1, the quality of the spots is eligible. To the annular and cross array, when the ranges are 0.082 9—0.131 6 and 0.085 1—0.098 2 respectively, the nugget quality is eligible.

  7. Mg/Cu共晶反应钎焊微观组织及力学特性分析%Microstructure and properties of welded joints of Mg/Cu by eutectic reaction brazing

    Institute of Scientific and Technical Information of China (English)

    王怀建; 白莉

    2013-01-01

    Magnesium alloy (AZ31B) and copper (T2) were bonded by eutectic reaction brazing technology, and effects of temperature on microstructures, tensile properties were studied. The microstructures of joints were investigated using scanning electron microscopy (SEM). And tensile strength test was performed on universal tensile testing machine. Results from the experiment show that when the welding temperature is 500 °C , its tensile strength can reach the maximum of 54 MPa, and the joint shows. brittle fracture.%采用共晶反应钎焊连接工艺对Mg/Cu异种材料进行连接,研究不同温度对接头微观组织及力学特性的影响.采用扫描电镜对焊接接头的微观组织进行研究,采用拉伸试验机研究接头的力学特性.研究表明:在焊接温度为500℃,焊接接头强度最高,最高抗拉强度为54 MPa,断口呈现脆性断裂特性.

  8. Research on the Welding Technology for Flame Brazing of Dissimilar Materials%异种材料火焰钎焊焊接工艺研究

    Institute of Scientific and Technical Information of China (English)

    熊亚

    2016-01-01

    The welding of dissimilar materials involves the welding structure of red copper and mild steel, and it adopts high silver welding flux, 37B, which silver content is 37 %. Because it contains very high proportion of pre-cious metal, silver, it is very costly. In order to solve this problem, this paper researches the welding material. On the condition of guaranteeing the quality, cost reduction is realized.%异种材料焊接,涉及到的紫铜和低碳钢的焊接结构,采用高银焊料37B(含银量37%)焊接,因其含有贵重金属银且占比极高,导致成本极其高昂。为解决此问题,本文对焊接材料进行研究,在保证产品质量的前提下,降低成本。

  9. Development of laser welding techniques for vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Strain, R.V.; Leong, K.H.; Smith, D.L. [Argonne National Laboratory, IL (United States)

    1996-10-01

    Laser welding is potentially advantageous because of its flexibility and the reduced amount of material affected by the weld. Bead-on-plate and butt welds were previously performed to depths of about 4 mm with a 6-kW CO{sub 2} laser on V-4%Cr-4%Ti and V-5%Cr-5%Ti alloys. These welds were made at a speed of 0.042 m/s using argon purging at a flow rate of 2.8 m{sup 3}/s. The purge was distributed with a diffuser nozzle aimed just behind the laser beam during the welding operation. The fusion zones of welds made under these conditions consisted of very fine, needle-shaped grains and were also harder than the bulk metal (230-270 dph, compared to {approx}180 dph for the bulk metal). A limited number of impact tests showed that the as-welded ductile-brittle transition temperatures (DBTT) was above room temperature, but heat treatment at 1000{degrees}C for 1 h in vacuum reduced the DBTT to <{minus}25{degrees}C. Activities during this reporting period focused on improvements in the purging system and determination of the effect of welding speed on welds. A 2-kW continuous YAG laser at Lumonics Corp. in Livonia, MI, was used to make 34 test welds for this study.

  10. 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.

  11. 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....

  12. Development of laser welding techniques for vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

    Strain, R.V.; Leong, K.H.; Smith, D.L.

    1996-04-01

    Laser welding is potentially advantageous because of its flexibility and the reduced amount of material affected by the weld. Lasers do not require a vacuum (as do electron beam welders) and the welds they produce high depth-to-width ratios. Scoping with a small pulsed 50 J YAG laser indicated that lasers could produce successful welds in vanadium alloy (V-5%Cr-5%Ti) sheet (1 mm thick) when the fusion zone was isolated from air. The pulsed laser required an isolating chamber filled with inert gas to produce welds that did not contain cracks and showed only minor hardness increases. Following the initial scoping tests, a series of tests were preformed with a 6 kW continuous CO{sub 2} laser. Successful bead-on-plate welds were made on V-4%Cr-4%Ti and V-5%Cr-5%Ti alloys to depths of about 4 mm with this laser.

  13. Application of acoustic emission technique and friction welding for excavator hose nipple

    International Nuclear Information System (INIS)

    Friction welding is a very useful joining process to weld metals which have axially symmetric cross section. In this paper, the feasibility of industry application was determined by analyzing the mechanical properties of weld region for a specimen of tube-to-tube shape for excavator hose nipple with friction welding, and optimized welding variables were suggested. In order to accomplish this object, friction heating pressure and friction heating time were selected as the major process variables and the experiment was performed in three levels of each parameter. An acoustic emission(AE) technique was applied to evaluate the optimal friction welding conditions nondestructively. AE parameters of accumulative count and event were analyzed in terms of generating trend of AE signals across the full range of friction weld. The typical waveform and frequency spectrum of AE signals which is generated by friction weld were discussed. From this study the optimal welding variables could be suggested as rotating speed of 1300 rpm, friction heating pressure of 15 MPa, and friction heating time of 10 sec. AE event was a useful parameter to estimate the tensile strength of tube-to tube specimen with friction weld.

  14. High temperature brazing of diamond tools

    Institute of Scientific and Technical Information of China (English)

    YAO Zheng-jun; SU Hong-hua; FU Yu-can; XU Hong-jun

    2005-01-01

    A new brazing technique of diamond was developed. Using this new technique optimum chemical and metallurgical bonding between the diamond grits and the carbon steel can be achieved without any thermal damages to diamond grits. The results of microanalysis and X-ray diffraction analysis reveal that a carbide layer exists between the diamond and the matrix, which consists of Cr3C2, Cr7C3 and Cr23C6. Performance tests show that the brazed diamond core-drill has excellent machining performance. In comparison with traditional electroplated diamond core-drill, the brazed diamond core-drill manufactured using the new developed technique has much higher machining efficiency and much longer operating life.

  15. Development of laser welded appendages to Zircaloy-4 fuel tubing (sheath/cladding)

    Energy Technology Data Exchange (ETDEWEB)

    Livingstone, S., E-mail: steve.livingstone@cnl.ca [Canadian Nuclear Laboratories Limited, Chalk River, ON, Canada K0J 1J0 (Canada); Xiao, L. [Canadian Nuclear Laboratories Limited, Chalk River, ON, Canada K0J 1J0 (Canada); Corcoran, E.C.; Ferrier, G.A.; Potter, K.N. [Department of Chemistry and Chemical Engineering, Royal Military College of Canada, Kingston, ON, Canada K7K 7B4 (Canada)

    2015-04-01

    Highlights: • Examines feasibility of laser welding appendages to Zr-4 tubing. • Laser welding minimizes the HAZ and removes toxic Be. • Mechanical properties of laser welds appear competitive with induction brazed joints. • Work appears promising and lays the foundation for further investigations. - Abstract: Laser welding is a potential alternative to the induction brazing process commonly used for appendage attachment in CANDU{sup ®} fuel fabrication that uses toxic Be as a filler metal, and creates multiple large heat affected zones in the sheath. For this work, several appendages were laser welded to tubing using different laser heat input settings and then examined with a variety of techniques: visual examination, metallography, shear strength testing, impact testing, and fracture surface analysis. Where possible, the examination results are contrasted against production induction brazed joints. The work to date looks promising for laser welded appendages. Further work on joint optimization, corrosion testing, irradiation testing, and post-irradiation examination will be performed in the future.

  16. Laser penetration spike welding : A microlaser welding technique enabling novel product designs and constructions

    NARCIS (Netherlands)

    Dijken, DK; Hoving, W; De Hosson, JTM

    2003-01-01

    A novel method for laser penetration microspot welding of sheet metal is presented. With this so called "laser spike-welding," large gap tolerances are allowed. Depending on the ratio of laser spot radius to top plate thickness, gaps of 100% of the top layer thickness and more can be bridged. With c

  17. 防锈铝板/镀锌钢板异种金属冷金属过渡熔钎焊接头的组织与抗拉强度%Microstructure and Tensile Strength of Rust-Proof Aluminum Plate and Zinc-Coated Steel Plates Braze-Weld Joint Prepared by Cold Metal Transfer

    Institute of Scientific and Technical Information of China (English)

    冯曰海; 王克鸿; 高飞; 杜刚

    2013-01-01

    The cold metal transfer (CMT) brazing-welding process was used to weld dissimilar metals of LF21 rust-proof aluminum plate and DD51D+Z zinc-coated steel plate,and the microstructure and tensile strength of the joint were studied.The results show that the compound layer of middle interface zone of the braze-weld joint was intermetallic compound FeAla with thickness of 4-6 μm.The average transverse tensile strength of the joint was up to 77 MPa and strength coefficient was 0.6.%采用冷金属过渡(CMT)熔钎焊接工艺,对LF21防锈铝板和DD51D+Z镀锌钢板进行了异种金属的连接,对接头的显微组织和抗拉强度进行了研究.结果表明:防锈铝板和镀锌钢板的熔钎焊接头的中间界面区化合物为4~6 μm厚的FeAl3金属间化合物,接头的平均横向抗拉强度为77MPa,接头的强度系数为0.6.

  18. Welding technique studies on the "West-East" pipeline project

    Institute of Scientific and Technical Information of China (English)

    Sui Yongli; Du Zeyu; Huang Fuxiang; Qi Lichun

    2006-01-01

    This paper described the work of welding process design for the "West-East" pipeline project, which is high pressure, large diameter and heavy wall thickness. According to the different geographical situation, climate, culture and the flexibility of the welding methods, this work recommended the semi-automatic process at the east and middle sections and automatic process at the west section of the pipeline project. The manual process is recommended on the tie-in joints and repairs. The double joint pipe and the 3 joint pipe are recommended at the water net place and some in-ditch welding place to reduce the welding volume. Also the special redesigned bevels are recommended for the automatic process and the semiautomatic process. Through all destructive tests, the results shows the welds are meet the requirements of related standards,specifications and design documents.

  19. A Study of Friction Stir Welded 2195 Al-Li Alloy by the Scanning Reference Electrode Technique

    Science.gov (United States)

    Donford, M. D.; Ding, R. J.

    1998-01-01

    A study of the corrosion of friction stir welded 2195 Al-Li alloy has been carried out using the scanning reference electrode technique (SRET). The results are compared to those obtained from a study of heterogeneously welded samples.

  20. Welding of Mo-Based Alloy Using Electron Beam and Laser-GTAW Hybrid Welding Techniques

    Science.gov (United States)

    Chatterjee, Anjan; Kumar, Santosh; Tewari, Raghvendra; Dey, Gautam Kumar

    2016-03-01

    In the current study, welding of TZM (molybdenum-based alloy) plates in square-butt configuration was carried out using electron beam and laser-GTAW hybrid power sources. Microstructures of weld joint containing three zones—parent metal, heat-affected zone, and fusion zone—were clearly identified when examined through optical and scanning electron microscopy. The weld joints were found to be sound with very wide fusion and heat-affected zones. The microstructure of the fusion zone was coarse-grained. as-solidified microstructure, while the microstructure of heat-affected zone was the recrystallized microstructure with reduction in grain size as distance from the fusion line increased. Microhardness profile using Vickers hardness tester was obtained across the weld region, and the tensile properties of the weld joints were evaluated by performing room temperature tensile test and fracture was examined using scanning electron microscope. Joint coefficient of the weld joints were ~40 to 45 pct of that of the parent metals with nonmeasurable tensile ductility with predominantly transgranular mode of fracture indicating weakness along the grain boundary. Detailed orientation imaging and transmission electron microscopy were carried out to understand the most dominating factor in introducing weld joint brittleness.

  1. 铝/镀锌钢薄板异种金属CMT熔钎焊接头组织与力学性能%Microstructure and Mechanical Properties of CMT Welding-brazing Joint for Dissimilar Materials between Aluminums and Galvanized Steels

    Institute of Scientific and Technical Information of China (English)

    余刚; 曹睿; 陈剑虹

    2012-01-01

    The dissimilar materials, aluminum alloys and galvanized steels were joined by CMT welding -brazing method. Analyzing the macro feature of cross -section, microstructure, the defects and mechanical properties of welding-brazing joints with SEM, EDAX, tension text, it is shown that the lap joints with better properties and better weld appearance are formed between the aluminum alloys and galvanized steels. From the microstructure and formation of weld metal, the cross-section of the joint can be divided into four zones; weld metal, middle interface, transitional interface and zinc - rich zone. There is a continuous and compact inter -metallic compound layers with a thickness of 3~4μm, which is formed in the brazing interface zone between the weld metal and the galvanized steel sheet. The main components of the layer are Fe3 Al, FeAl2, Fe2 Al5 and FeAl3,then, the zinc-rich zone is mainly composed of aluminum -rich solid solution and residue of Zn. Tensile strength tests show that the joint is fractured in the aluminum heat affect zone, and the joint strength with 204MPa is obtained.%采用冷金属过渡方法对铝合金和镀锌钢板进行了熔钎焊连接,使用扫描电镜、能谱分析和拉伸试验分析了接头的截面形貌、组织特征、焊接缺陷及力学性能.试验结果表明,铝合金和镀锌钢能得到成形美观、性能良好的搭接接头.对焊缝金属的组织特征分析表明,焊接接头由熔化区、中心界面区、过渡界面区和富锌区组成,在焊缝金属和镀锌板的界面区形成厚度为3~4μm的金属间化合物层(主要成分为Fe3Al、FeAl2、Fe2Al5和FeAl3),富锌区由富铝的固溶体和残留的锌组成.在进行拉伸试验时,断裂发生在热影响区,接头强度为204MPa.

  2. Brazing technology of Ti alloy/stainless steel dissimilar metal joint at system integrated modular advanced reactor

    International Nuclear Information System (INIS)

    For the technoldogy development of brazing Ti alloy to stainless steel joints used at SMART, the status of brazing technology development, brazing processes, and the brazing technology of Ti alloy and stainless steel are reviewed. Because fusion welding process cannot be applied due to the formation of intermetallic compounds in the weld metal, brazing joint was selected at the design. The joint part is assembled with a thread composed with male part of Ti alloy tube and female part of stainless tube. The gap in the thread will be filled with brazing filler metal. However, brittle Ti-Fe intermetallic compounds are formed at the surface of stainless steel through the diffusion of Ti at the melt. Brazing conditions should be set-up to reduce the formation of intermetallic compounds. For that, 3 kinds of Ag filler metals were selected as the candidates and heating will be done with induction and electric furnaces. Through measuring of joint strength according to the control of pre- and post-braze treatment, heating rate and heating time, optimal brazing method will be fixed. To qualify the brazing procedure and performance and to check defects in final product, the inspection plan will be established according to the req2wuirements of AWS and ASME

  3. Brazing technology of Ti alloy/stainless steel dissimilar metal joint at system integrated modular advanced reactor

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Sang Chul; Kim, Sung Ho; Kim, Yong Wan; Kim, Jong In

    2001-02-01

    For the technoldogy development of brazing Ti alloy to stainless steel joints used at SMART, the status of brazing technology development, brazing processes, and the brazing technology of Ti alloy and stainless steel are reviewed. Because fusion welding process cannot be applied due to the formation of intermetallic compounds in the weld metal, brazing joint was selected at the design. The joint part is assembled with a thread composed with male part of Ti alloy tube and female part of stainless tube. The gap in the thread will be filled with brazing filler metal. However, brittle Ti-Fe intermetallic compounds are formed at the surface of stainless steel through the diffusion of Ti at the melt. Brazing conditions should be set-up to reduce the formation of intermetallic compounds. For that, 3 kinds of Ag filler metals were selected as the candidates and heating will be done with induction and electric furnaces. Through measuring of joint strength according to the control of pre- and post-braze treatment, heating rate and heating time, optimal brazing method will be fixed. To qualify the brazing procedure and performance and to check defects in final product, the inspection plan will be established according to the req2wuirements of AWS and ASME.

  4. Joining techniques for core flow test loop fuel rod simulators

    International Nuclear Information System (INIS)

    Laser welding and furnace brazing techniques have been developed to join subassemblies for fuel rod simulators (FRSs) that have survived up to 1000-h steady-state operation at 700 to 11000C cladding temperatures and over 5000 thermal transients, ranging from 10 to 500C/s. A pulsed-laser welding procedure uses small diameter filler wire to join one end of a resistance heating element to a tubular conductor. The other end of the heating element is laser welded to an end plug, which in turn is welded to a central conductor. Before these welding operations, the intermediate material conductors (either tubular or rod) are vacuum brazed to matching copper leads. On room temperature tensile testing, 10 of 11 brazements between copper and nickel rods failed in the copper rather than the brazement. The thin walls and ductility of the copper and nickel tubular conductors caused joint machining and fitup problems. Accordingly, it has not been possible to consistently produce tensile test samples of brazed dissimilar metal tubular conductors that will fail outside the joint area. A unique tubular electrode carrier has also been developed for gas tungsten arc welding FRSs to the tubesheet of a test assembly. Two seven-rod mockups of the simulator-to-tubesheet joint area were welded and successfully cycled 500 times from 3700C (6980F) down to 1000C (2120F) with an internal pressure of 11.72 MPa (1700 psi). No leakage was detected by helium mass spectrometry, either before or after testing. Modified versions of the electrode carrier were developed for brazing electrical leads to the upper ends of the FRSs. Satisfactory brazes have been made on both single-rod mockups and arrays of simulators

  5. Plastic welding techniques based on torsional and circular motion.

    Science.gov (United States)

    Kising, J

    2001-05-01

    The torsion ultrasonic welding process and the frequency decoupled circular friction process at low frequencies deliver low particle production. In addition, the even, circular movement of the circular welding process over the whole seam area and the freely selectable frequency open up applications in the medical field that cannot be achieved, or can only be achieved with difficulty, by traditional welding processes. The processes are fast and can be process controlled to a fine degree with a facility to be integrated into automation lines. PMID:11521653

  6. Application of slip-band visualization technique to tensile analysis of laser-welded aluminum alloy

    OpenAIRE

    Muchiar, Ir.; Yoshida, S.; Widiastuti, R.; Kusnovo, A.; Takahashi, K; Sato, S.

    1996-01-01

    Recently we have developed a new optical interferometric technique capable of visualizing slip band occurring in a deforming solid-state object. In this work we applied this technique to a tensile analysis of laser-welded aluminum plate samples, and successfully revealed stress concentration that shows strong relationships with the tensile strength and the fracture mechanism. We believe that this method is a new, convenient way to analyze the deformation characteristics of welded objects and ...

  7. Characteristics of precoating TIG welding-brazing joint of aluminum alloy to stainless steel%铝合金/不锈钢预涂层钨极氩弧熔钎焊接头的特性

    Institute of Scientific and Technical Information of China (English)

    宋建岭; 林三宝; 杨春利; 马广超

    2009-01-01

    通过在不锈钢表面预涂钎剂层,采用铝硅共晶钎料实现铝合金/不锈钢TIG熔钎焊连接,获得具有熔焊与钎焊双重性质的对接接头,运用OM、SEM、EDS分析接头的微观组织及成分,通过拉伸实验评定接头的力学性能.结果表明:铝母材局部熔化,与液态钎料混合后凝固形成焊缝,焊缝组织主要由α(Al)基体和在晶界析出的Al-Si共晶相组成;不锈钢不发生熔化,液态钎料与不锈钢在界面反应形成不均匀分布的金属间化合物层,最大厚度不超过10 μm,界面上部金属间化合物较厚,呈锯齿状,主要相成分为α(τ5)-Al7.4Fe2Si;界面下部金属间化合物较薄,呈细须状,由α(τ5)-Al7.4Fe2Si+α(Al)混合相构成;接头的平均抗拉强度为90.6 MPa,焊缝/不锈钢界面下部为连接的薄弱环节,成为断裂的起始位置.%Dissimilar metals TIG welding-brazing of aluminum alloy to stainless steel was conducted using Al-Si eutectic wire with precoating special flux layer on the steel surface. The microstructure characteristics of aluminum alloy/stainless steel butt joint were analyzed by OM, SEM and EDS, and the tensile strength of the joint was measured by instron-testing machine. The results show that the aluminum base material is melted and mixed with the liquid filler metal to form the welded seam, which consists of α(Al) matrix and Al-Si eutectic phases in the intergranular. The stainless steel is not melted and reacts with the melted metal to form nonuniform intermetallic compound (IMC) at the welded seam/steel interfacial layer, of which the thickness is less than 10 μm. At the upper part of the layer, the IMC is thick and presents serrated-shape and consists of α(τ5)-Al7.4Fe2Si phase, while at the lower part, the IMC is thinner than the upper part and presents thin whiskered-shape and consists of α(τ5)-Al7.4Fe2Si+α(Al) mixed phases. The average tensile strength of joints is 90.6 MPa and the fracture starts at the lower part of

  8. Defocusing Techniques for Multi-pass Laser Welding of Austenitic Stainless Steel

    Science.gov (United States)

    Karhu, Miikka; Kujanpää, Veli

    This study introduces an experimental work carried out in multi-pass laser welding with cold filler wire and laser-arc hybrid welding of thick section austenitic stainless steel. As it has been demonstrated earlier, hybrid and cold wire welding with a keyhole-mode can offer very efficient way to produce multi-pass welds in narrow gap thick section joints. However, when multi-pass welding is applied to one pass per layer method without e.g. scanning or defocusing, the used groove width needs to be very narrow in order to ensure the proper melting of groove side walls and thus to avoid lack of fusion/cold-run defects. As a consequence of the narrow groove, particularly in thick section joints, the accessibility of an arc torch or a wire nozzle into the very bottom of a groove in root pass welding can be considerably restricted. In an alternative approach described in this paper, a power density of a laser beam spot was purposely dispersed by using a defocusing technique. In groove filling experiments, a power density of defocused laser beam was kept in the range, which led the welding process towards to conduction limited regime and thus enabled to achieve broader weld cross-sections. The object was to study the feasibility of defocusing as a way to fill and bridge wider groove geometries than what can be welded with focused keyhole-mode welding with filler addition. The paper covers the results of multi-pass welding of up to 60 mm thick joints with single side preparations.

  9. A non-conventional technique for evaluating welded joints based on the electrical conductivity

    Energy Technology Data Exchange (ETDEWEB)

    Santos, T.G.; Sorger, G., E-mail: telmo.santos@fct.unl.pt, E-mail: lgs18243@campus.fct.unl.pt [Universidade Nova de Lisboa, UNIDEMI, Departamento de Engenharia Mecanica e Industrial, Faculdade de Ciencias e Tecnologia, Caparica (Portugal); Vilaca, P., E-mail: pedro.vilaca@aalto.fi [Aalto Univ., Dept. of Engineering Design and Production, School of Engineering, Aalto (Finland); Miranda, R., E-mail: rmiranda@fct.unl.pt [Universidade Nova de Lisboa, UNIDEMI, Departamento de Engenharia Mecanica e Industrial, Faculdade de Ciencias e Tecnologia, Caparica (Portugal)

    2015-01-15

    Recent studies showed that electrical conductivity is a valuable technique to identify the different zones of solid-state welded joints with a good correlation with the microstructure and hardness. This is a relevant result since this technique is fast and, in some cases, non destructive, The concept was applied to other welding processes such as the ones involving fusion to a wide range of materials, For this, a comprehensive study was performed using friction stir welding, tungsten inert gas (TlG) and gas metal arc (MAG) welding processes in either bead on plate or butt joints in: carbon steel, magnesium and titanium, Eddy current nondestructive testing (NDT) was used to measure the electrical conductivity at different depths in transverse sections of the processed materials. The profiles were compared to the hardness profiles in the same sections. As a result, a correlation was observed in most materials welded by solid state and by fusion processes. The variation of the electrical conductivity closely follows that measured in the hardness. Another interesting conclusion is that, even for fusion welding of carbon steels, the technique has potential to complement the hardness measurements and microstructural observations, allowing the identification of the distinct zones of welds in materials commonly used in industry. (author)

  10. Ultrasonic inspection techniques for two weld closures proposed for RSSF waste storage casks

    International Nuclear Information System (INIS)

    One method being considered for interim storage of high-level radioactive waste materials is to place these materials in large sealed stainless steel canisters and subsequently store these canisters in a second sealed steel storage cask. Weld procedures are proposed as the closure or seal for these vessels. Inspection of these closures to assure initial and long-term integrity of the closure welds presents a challenge to nondestructive testing. The environment is thermally (400 to 10000F) and radioactively (105 R/hr) hot necessitating remote inspection procedures. As a result of research work, ultrasonic test techniques were developed for inspecting the final weld closure of the waste cask. Special transducers, coupling techniques and fixturing were developed and demonstrated in a mockup test facility by remotely examining a 2-in. full penetration weld closure. The examination was performed at room ambient and at a temperature of 2000F. Testing at the desired temperature of 4000F was not completed due to a loss in transducer performance at temperatures in excess of 2000F. Upon completion of the mockup test demonstration, the cask was subjected to a drop test. The ultrasonic results of the pre- and post-examination of two weld closures (the 2-in. full penetration weld and the threaded plug with seal weld) are presented. After the completion of the drop test, both weld closures were radiographed. The radiographs verified the ultrasonic examination and the presence of weld defects in the same areas. Sectioning of the cask closure welds with metallographic verification was not completed at the time of this writing. As a result of the experience gained from the Retrievable Surface Storage Facility (RSSF) storage cask program, recommendations pertaining to the nondestructive engineering development program for Spent Unreprocessed Fuel (SURF) storage casks are presented

  11. Development of Evaluation Technique of GMAW Welding Quality Based on Statistical Analysis

    Institute of Scientific and Technical Information of China (English)

    FENG Shengqiang; TERASAKI Hidenri; KOMIZO Yuichi; HU Shengsun; CHEN Donggao; MA Zhihua

    2014-01-01

    Nondestructive techniques for appraising gas metal arc welding(GMAW) faults plays a very important role in on-line quality controllability and prediction of the GMAW process. On-line welding quality controllability and prediction have several disadvantages such as high cost, low efficiency, complication and greatly being affected by the environment. An enhanced, efficient evaluation technique for evaluating welding faults based on Mahalanobis distance(MD) and normal distribution is presented. In addition, a new piece of equipment, designated the weld quality tester(WQT), is developed based on the proposed evaluation technique. MD is superior to other multidimensional distances such as Euclidean distance because the covariance matrix used for calculating MD takes into account correlations in the data and scaling. The values of MD obtained from welding current and arc voltage are assumed to follow a normal distribution. The normal distribution has two parameters: the meanm and standard deviations of the data. In the proposed evaluation technique used by the WQT, values of MD located in the range from zero tom+3s are regarded as “good”. Two experiments which involve changing the flow of shielding gas and smearing paint on the surface of the substrate are conducted in order to verify the sensitivity of the proposed evaluation technique and the feasibility of using WQT. The experimental results demonstrate the usefulness of the WQT for evaluating welding quality. The proposed technique can be applied to implement the on-line welding quality controllability and prediction, which is of great importance to design some novel equipment for weld quality detection.

  12. Development and validation of predictive simulation model of multi-layer repair welding process by temper bead technique

    International Nuclear Information System (INIS)

    Stress corrosion cracking (SCC) has recently been observed in the nickel base alloy weld metal of dissimilar pipe joint used in pressurized water reactor (PWR) . Temper bead technique has been developed as one of repair procedures against SCC applicable in case that post weld heat treatment (PWHT) is difficult to carry out. In this regard, however it is essential to pass the property and performance qualification test to confirm the effect of tempering on the mechanical properties at repair welds before temper bead technique is actually used in practice. Thus the appropriate welding procedure conditions in temper bead technique are determined on the basis of the property and performance qualification testing. It is necessary for certifying the structural soundness and reliability at repair welds but takes a lot of work and time in the present circumstances. Therefore it is desirable to establish the reasonable alternatives for qualifying the property and performance at repair welds. In this study, mathematical modeling and numerical simulation procedures were developed for predicting weld bead configuration and temperature distribution during multi-layer repair welding process by temper bead technique. In the developed simulation technique, characteristics of heat source in temper bead welding are calculated from weld heat input conditions through the arc plasma simulation and then weld bead configuration and temperature distribution during temper bead welding are calculated from characteristics of heat source obtained through the coupling analysis between bead surface shape and thermal conduction. The simulation results were compared with the experimental results under the same welding heat input conditions. As the results, the bead surface shape and temperature distribution, such as Acl lines, were in good agreement between simulation and experimental results. It was concluded that the developed simulation technique has the potential to become useful for accurate

  13. Application of Ultrasonic inspection Technique on Fuel Rod Seam Weld

    International Nuclear Information System (INIS)

    As of the end of March, 1996, 26 BWR power plants of which station capacity has reached up to 23,000 GW in total are in commercial operation in Japan, Japan Nuclear Fuel (JNF), a BWR fuel fabricator in Japan, has supplied fuels to those power plants for 25 years. This paper presents refinement of inspection technology applied to enhance completeness of fuel rod welding at JNF, which has cumulatively produced approximately 50,000 fuel bundles to the date in Japan. In this operation, TIG method has been employed for plug to tube welding of fuel rod, and X-ray radiography was formerly applied as nondestructive testing (NDT) means in order to verify weld integrity of every fuel rod. As there was limited capabilities of X-ray radiography such as shooting time and direction, and also inspection of fuel rod weld integrity is one of key characteristics of regulatory inspection according to the law, JNF has developed and applied more reliable and effective probe rotation type ultrasonic method. This paper presents refinement of inspection technology applied to enhance completeness of fuel rod welding at JNF

  14. Ultrapulse welding: A new joining technique. [for automotive industry

    Science.gov (United States)

    Anderson, D. G.

    1972-01-01

    The ultrapulse process is a resistance welding process that utilizes unidirectional current of high magnitude for a very short time with a precisely controlled dynamic force pulse. Peak currents of up to 220,000 amperes for two to ten milliseconds are used with synchronized force pulses of up to nine thousand pounds. The welding current passing through the relatively high resistance of the interface between the parts that are being joined results in highly localized heating. Described is the UPW process as it applies to the automotive industry.

  15. Nondestructive, in-process inspection of inertia friction welding : an investigation into a new sensing technique.

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, D. A. (Daniel A.); Cola, M. J. (Mark J.); Dave, V. R. (Vivek R.); Dozhier, N. G. (Nathan G.); Carpenter, R. W. (Robert W.)

    2002-01-01

    This paper investigates the capabilities of a new sensor for in-process monitoring of quality during friction welding. The non-contact sensor is composed of microphones that are mounted in an aluminum ring which surrounds the weld joint. The sensor collects the acoustical energy (in the form of sound pressure) that is emitted during the plastic deformation and phase transformations (if applicable) in friction welding processes. The focus in this preliminary investigation is to search for and identify features within the acoustical emission that are indicative of bond quality. Bar-to-bar inertia friction welding (one form of friction welding) of copper to 304L stainless steel is used in this proof-of-concept study. This material combination exhibits only marginal weldability and is ideally suited for validating the capabilities of this new sensing technique. A probabilistic neural network is employed in this work to analyze the acoustical emission's frequency spectrum in an attempt to classify acceptable, conditional, and unacceptable welds. Our preliminary findings indicate that quality-based process features do exist within the frequency spectrum of the acoustical signature. The results from this analysis are presented. Future work in improving the sensing and interpretation of the data is discussed in an effort to develop a robust method of quality-based, in-process monitoring of friction welds.

  16. Metallic glass coating on metals plate by adjusted explosive welding technique

    International Nuclear Information System (INIS)

    Using an adjusted explosive welding technique, an aluminum plate has been coated by a Fe-based metallic glass foil in this work. Scanning electronic micrographs reveal a defect-free metallurgical bonding between the Fe-based metallic glass foil and the aluminum plate. Experimental evidence indicates that the Fe-based metallic glass foil almost retains its amorphous state and mechanical properties after the explosive welding process. Additionally, the detailed explosive welding process has been simulated by a self-developed hydro-code and the bonding mechanism has been investigated by numerical analysis. The successful welding between the Fe-based metallic glass foil and the aluminum plate provides a new way to obtain amorphous coating on general metal substrates.

  17. Welding technique and quality of large diameter X70 line pipe for gas transmission of China

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    X70 grade large diameter line pipe with helical and longitudinal seam SAW was developed and used in West-East Pipeline Project of Petrochina. The operation pressure of the pipeline was designed as 10 MPa, with diameter of 1016 mm OD. This project represents the first high-pressure, large diameter and high strength grade gas pipeline in China. All the factors affecting the safety of the pipeline shall be considered. The welds quality of line pipe is very important for safety of the pipeline. Acicular ferrite type X70 grade pipeline steel was adopted for the base material. The welds performances of X70 line pipes with 1016mm OD and 14.6-21.0 mm WT has reached a very high level, especially of low temperature Charpy V impact toughness of welds metal. Welding technique and quality status of X70 line pipe of China are investigated in this paper.

  18. 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…

  19. Evaluated Plan Stress Of Weld In Pressure Tube Using X Ray Diffraction Technique

    International Nuclear Information System (INIS)

    X ray diffraction is a fundamental technique measuring stress, this technique has determined crystal strain in materials, from that determined stress in materials. This paper presents study of evaluating plane stress of weld in pressure tube, using modern XRD apparatus: X Pert Pro. (author)

  20. Characterisation of nuclear fuel element welds of stainless steel and zircaloy made by GTAW, EBW and LBW techniques

    International Nuclear Information System (INIS)

    Fuel elements are fabricated by welding the end plugs to the fuel tubes. GTAW is widely practiced in view of its simplicity and low cost. EBW and LBW techniques are being developed because of better process control and flexibility. In this paper we have studied the welds made by these techniques. The study includes optical and scanning electron microscopy, microhardness measurements and EPMA of these welds

  1. Development of a pseudo phased array technique using EMATs for DM weld testing

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, Adam C., E-mail: adam.cobb@swri.org; Fisher, Jay L., E-mail: adam.cobb@swri.org [Southwest Research Institute, Sensor Systems and Nondestructive Technology Department, 6220 Culebra Road, San Antonio, TX 78238-5166 (United States); Shiokawa, Nobuyuki; Hamano, Toshiaki; Horikoshi, Ryoichi; Ido, Nobukazu [IHI Corporation, Nuclear Power Operations, Yokohama Engineering Center, 1, Shin-Nakahara-cho, Isogo-ku, Yokohama 235-8501 (Japan)

    2015-03-31

    Ultrasonic inspection of dissimilar metal (DM) welds in piping with cast austenitic stainless steel (CASS) has been an area ongoing research for many years given its prevalence in the petrochemical and nuclear industries. A typical inspection strategy for pipe welds is to use an ultrasonic phased array system to scan the weld from a sensor located on the outer surface of the pipe. These inspection systems generally refract either longitudinal or shear vertical (SV) waves at varying angles to inspect the weld radially. In DM welds, however, the welding process can produce a columnar grain structure in the CASS material in a specific orientation. This columnar grain structure can skew ultrasonic waves away from their intended path, especially for SV and longitudinal wave modes. Studies have shown that inspection using the shear horizontal (SH) wave mode significantly reduces the effect of skewing. Electromagnetic acoustic transducers (EMATs) are known to be effective for producing SH waves in field settings. This paper presents an inspection strategy that seeks to reproduce the scanning and imaging capabilities of a commercial phase array system using EMATs. A custom-built EMAT was used to collect data at multiple propagation angles, and a processing strategy known as the synthetic aperture focusing technique (SAFT) was used to combine the data to produce an image. Results are shown using this pseudo phased array technique to inspect samples with a DM weld and artificial defects, demonstrating the potential of this approach in a laboratory setting. Recommendations for future work to transition the technique to the field are also provided.

  2. Development of a pseudo phased array technique using EMATs for DM weld testing

    Science.gov (United States)

    Cobb, Adam C.; Fisher, Jay L.; Shiokawa, Nobuyuki; Hamano, Toshiaki; Horikoshi, Ryoichi; Ido, Nobukazu

    2015-03-01

    Ultrasonic inspection of dissimilar metal (DM) welds in piping with cast austenitic stainless steel (CASS) has been an area ongoing research for many years given its prevalence in the petrochemical and nuclear industries. A typical inspection strategy for pipe welds is to use an ultrasonic phased array system to scan the weld from a sensor located on the outer surface of the pipe. These inspection systems generally refract either longitudinal or shear vertical (SV) waves at varying angles to inspect the weld radially. In DM welds, however, the welding process can produce a columnar grain structure in the CASS material in a specific orientation. This columnar grain structure can skew ultrasonic waves away from their intended path, especially for SV and longitudinal wave modes. Studies have shown that inspection using the shear horizontal (SH) wave mode significantly reduces the effect of skewing. Electromagnetic acoustic transducers (EMATs) are known to be effective for producing SH waves in field settings. This paper presents an inspection strategy that seeks to reproduce the scanning and imaging capabilities of a commercial phase array system using EMATs. A custom-built EMAT was used to collect data at multiple propagation angles, and a processing strategy known as the synthetic aperture focusing technique (SAFT) was used to combine the data to produce an image. Results are shown using this pseudo phased array technique to inspect samples with a DM weld and artificial defects, demonstrating the potential of this approach in a laboratory setting. Recommendations for future work to transition the technique to the field are also provided.

  3. An Evaluation of Welding Processes to Reduce Hexavalent Chromium Exposures and Reduce Costs by Using Better Welding Techniques

    OpenAIRE

    Keane, Michael J.

    2014-01-01

    A group of stainless steel arc welding processes was compared for emission rates of fume and hexavalent chromium, and costs per meter length of weld. The objective was to identify those with minimal emissions and also compare relative labor and consumables costs. The selection included flux-cored arc welding (FCAW), shielded-metal arc welding (SMAW), and multiple gas metal arc welding (GMAW) processes. Using a conical chamber, fumes were collected, and fume generation rates and hexavalent chr...

  4. MICROSTRUCTURE ANALYSIS OF INTERFACIAL LAYER WITH TUNGSTEN INERT GAS WELDING-BRAZING JOINT OF ALUMINUM ALLOY/STAINLESS STEEL%铝合金/不锈钢钨极氩弧熔-钎焊接头界面层的微观结构分析

    Institute of Scientific and Technical Information of China (English)

    林三宝; 宋建岭; 杨春利; 马广超

    2009-01-01

    Against the background of the required weight reduction in transportation through lightweight construction, the application of hybrid structures, where aluminum alloy and steel are jointed together, has a high technical and economical potential. But jointing of material combinations of aluminum alloy and steel is problematic by fusion welding since brittle intermetallic compounds (IMCs) are formed between aluminum alloy and steel. Nowadays, tungsten inert gas (TIG) welding-brazing offers a great potential for aluminum alloy and steel jointing. In this process, the sheet and filler metal are heated or melted by TIG heat, and the joint has a dual characteristic: in aluminum alloy side it is a welding joint, while in steel side it is a brazing joint. However, in the dynamic heating process, the heating temperature changes so quickly and the reaction time between the liquid filler metal and solid steel is so short that it is more difficult to control the IMC layer's growth, predominantly its thickness and microstructures. Most of past reports about the brazing of aluminum alloy and steel indicate Al-Fe binary IMC layers, e.g., Fe_2Al_5 and FeAl_3, formed in the brazing joint, which are detrimental to the mechanical properties of the joint. Si additions are used to limit the growth of the brittle Al-Fe IMC layer between aluminum alloy and steel by replacing Al-Fe phases with less detrimental Al-Fe-Si phases in aluminizing and furnace brazing of aluminum alloy and steel. By now, there have been few reports of investigating the interfacial layer of TIG welding-brazing joint of aluminum alloy and stainless steel. In this paper, a butt TIG welding-brazing joint of aluminum alloy/stainless steel was formed using Al-Si eutectic filler wire with modified Noclock flux precoated on a steel surface. The microstructure characteristics of the welded seam-steel interfacial layer were analyzed by OM, SEM and EDS and its mechanical properties were measured by dynamic ultra

  5. Micro-focus x-ray inspection of the bearing pad welded by laser for CANDU fuel element

    International Nuclear Information System (INIS)

    To attach the bearing pads on the surface of CANDU fuel element, laser welding technique has been reviewed to replace brazing technology which is complicate process and makes use of the toxic beryllium. In this study, to evaluate the soundness of the weld of the bearing pad of CANDU fuel element, a precise X-ray inspection system was developed using a micro-focus X-ray generator with an image intensifier and a real time camera system. The weld of the bearing pad welded by Nd:YAG laser has been inspected by the developed inspection system. Image processing technique has been applied to reduce random noise and to enhance the contrast of the X-ray image. A few defects on the weld of the bearing pads have been detected by the X-ray inspection process

  6. Al-Si-Mn Alloy Coating on Aluminum Substrate Using Cold Metal Transfer (CMT) Welding Technique

    Science.gov (United States)

    Rajeev, G. P.; Kamaraj, M.; Bakshi, S. R.

    2014-06-01

    The cold metal transfer (CMT) process was explored as a weld overlay technique for synthesizing Al-Si-Mn alloy coating on a commercially pure Al plate. The effect of welding speed on the bead geometry, deposition rate, and the dilution were studied and the best parameter was used to synthesize the coatings. The CMT process can be used to produce thick coatings (>2.5 mm) without porosity and with low dilution levels. The Vickers hardness number of the Al substrate increased from 28 in the bulk to 57 in the coating. It is suggested that the CMT process can be an effective and energy-efficient technique for depositing thick coatings and is useful in weld repair of aluminum alloy components.

  7. Inspection of pipeline girth welds with ultrasonic phased array technique

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A novel automatic ultrasonic system used for the inspection of pipeline girth welds is developed, in which a linear phased array transducer using electronic scan is adopted. Optimal array parameters are determined based on a mathematical model of acoustic field for linear phased array derived from Huygens' principle. The testing method and the system structure are introduced. The experimental results show that the phased array transducer system has the same detectability as that of conventional ultrasonic transducer system, but the system architecture can be simplified greatly, and the testing flexibility and the testing speed can be improved greatly.

  8. Brazing zone structure at active brazing of alumina ceramics

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    @@ Nowadays one of the most effective methods of joining of oxide ceramics with other elements of construction is active brazing based on using of active metals (Ti, Zr), which increase reactivity of brazing alloy relative to ceramic element of a joining.

  9. Brazing zone structure at active brazing of alumina ceramics

    Institute of Scientific and Technical Information of China (English)

    Demchuk; V.; A.; Kalinichenko; B.; B.

    2005-01-01

    Nowadays one of the most effective methods of joining of oxide ceramics with other elements of construction is active brazing based on using of active metals (Ti, Zr), which increase reactivity of brazing alloy relative to ceramic element of a joining.……

  10. Characterization of Nitinol Laser-Weld Joints by Nondestructive Testing

    Science.gov (United States)

    Wohlschlögel, Markus; Gläßel, Gunter; Sanchez, Daniela; Schüßler, Andreas; Dillenz, Alexander; Saal, David; Mayr, Peter

    2015-12-01

    Joining technology is an integral part of today's Nitinol medical device manufacturing. Besides crimping and riveting, laser welding is often applied to join components made from Nitinol to Nitinol, as well as Nitinol components to dissimilar materials. Other Nitinol joining techniques include adhesive bonding, soldering, and brazing. Typically, the performance of joints is assessed by destructive mechanical testing, on a process validation base. In this study, a nondestructive testing method—photothermal radiometry—is applied to characterize small Nitinol laser-weld joints used to connect two wire ends via a sleeve. Two different wire diameters are investigated. Effective joint connection cross sections are visualized using metallography techniques. Results of the nondestructive testing are correlated to data from destructive torsion testing, where the maximum torque at fracture is evaluated for the same joints and criteria for the differentiation of good and poor laser-welding quality by nondestructive testing are established.

  11. 75 FR 74083 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Welding...

    Science.gov (United States)

    2010-11-30

    ... ] additional information, see the related notice published in the Federal Register on August 24, 2010 (75 FR...; Welding, Cutting and Brazing ACTION: Notice. SUMMARY: The Department of Labor (DOL) hereby announces the... request (ICR) titled, ``Welding, Cutting and Brazing,'' to the Office of Management and Budget (OMB)...

  12. Brazing of AM-350 stainless steel LWBR fuel rod support grids (LWBR Development Program)

    Energy Technology Data Exchange (ETDEWEB)

    Ebejer, L.P.

    1979-02-01

    A brazing process has been developed wherein several hundred stamped AM-350 stainless steel sheet metal components, wire components and machined bar components were simultaneously joined together to fabricate about 400 grids of different sizes for the LWBR fuel rod support system. High temperature (2110F +- 20F) vacuum brazing was employed using Ni--Cr--Si braze alloy filler metal in the form of paste. Techniques employed in the assembly, braze alloy application and fixturing of grids to achieve adequate dimensional control are discussed in detail. The brazing thermal cycle as related to the complex metallurgical process of both AM-350 stainless steel and the Ni--Cr--Si braze alloy is also discussed.

  13. Optimization of Thermal Aspects of Friction Stir Welding – Initial Studies Using a Space Mapping Technique

    DEFF Research Database (Denmark)

    Larsen, Anders Astrup; Bendsøe, Martin P.; Schmidt, Henrik Nikolaj Blicher;

    2007-01-01

    The aim of this paper is to optimize a thermal model of a friction stir welding process. The optimization is performed using a space mapping technique in which an analytical model is used along with the FEM model to be optimized. The results are compared to traditional gradient based optimization...

  14. Evaluation of Bending Strength in Friction Welded Alumina/mild Steel Joints by Applying Factorial Technique

    Science.gov (United States)

    Jesudoss Hynes, N. Rajesh; Nagaraj, P.; Vivek Prabhu, M.

    Joining of metal with ceramics has become significant in many applications, because they combine properties like ductility with high hardness and wear resistance. By friction welding technique, alumina can be joined to mild steel with AA1100 sheet of 1mm thickness as interlayer. In the present work, investigation of the effect of friction time on interlayer thickness reduction and bending strength is carried out by factorial design. By using ANOVA, a statistical tool, regression modeling is done. The regression model predicts the bending strength of welded ceramic/metal joints accurately with ± 2% deviation from the experimental values.

  15. Measurement of inhomogeneous strength in weld joint by 3D image correlation technique

    International Nuclear Information System (INIS)

    It is possible for stress corrosion cracking to occur in weld joints and their neighborhood of nuclear power plants. Crack growth prediction and fracture assessment based on fitness-for-service is applied to initiated cracks. Yield point and tensile strength of material is used for fracture assessment. However, the material strength distribution of a welded part is usually not uniform. Therefore, to assess structural integrity correctly, it is important to understand the inhomogeneous strength distribution. In this study, identification of an inhomogeneous material strength distribution of a welded part was tried using a digital image correlation technique (DIC). A specimen was taken from a butt welded joint and the displacement of the specimen surface during a tensile test was measured using the DIC. It was shown that the nominal stress-local strain curves on a specimen surface and 0.2% proof strength distribution around the weld part could be corrected by the DIC. Furthermore, change in the cross-section during the tensile test was estimated by the DIC, and the local stress (true stress) at an arbitrary cross-section of the specimen could be identified. (author)

  16. Active brazed diamond and cubic boron nitride interfacial nanostructure and application

    International Nuclear Information System (INIS)

    Active brazing is an effective technique for joining diamond or cBN grit onto metallic substrates. Current use of this technique is being made for super abrasive, high performance tools. The lecture will give an overview over different aspects such as (i) tool performance in selected applications, (ii) interfacial nanostructure between super abrasive grit and brazing alloys matrix, (iii) attempts to computer model such interface reactions and (iv) recent improvements of the abrasion resistance of the brazing alloy itself. Super abrasive tools with outstanding performance in applications such as grinding, honing or stone cutting can be manufactured by a single-layer of brazed diamond or cBN grit. A method to obtain regular grit patterns will be presented. Examples of prototype tools and their performance in different applications will be shown. The investigation of interface reactions between diamond and active brazing alloys plays an important role to further improve the brazing process and resulting tool performance. The interfacial nanostructure is characterised by a thin reaction layer of Ti with diamond and cBN, respectively. Results for Ag- and Cu-based brazing alloys will be presented and discussed in view of the influence of brazing process parameters and brazing alloy matrix. Computer modelling of the thermodynamics and kinetics of the interface reactions may allow optimising the process parameters. This requires reliable databases currently being built up. The potential of such methods in ceramic to metal joining will be described. The abrasion resistance of brazing alloys itself plays an important role for tool performance. A new method to achieve a dispersion of nano sized TiC precipitates in the alloy matrix by addition of an organic binder, decomposing during brazing will be presented. In an outlook further applications of brazed diamond grit, such as thermal management materials will be discussed. (author)

  17. Ultrasonic inspection of tube to tube plate welds

    International Nuclear Information System (INIS)

    To monitor the deterioration of a weld between a tube and tube plate which has been repaired by a repair sleeve inside the tube and brazed at one end to the tube, ultrasound from a crystal at the end of a rod is launched, in the form of Lamb-type waves, into the tube through the braze and allowed to travel along the tube to the weld and be reflected back along the tube. The technique may also be used for the type of heat exchanger in which, during construction, the tubes are welded to the tube plate via external sleeves in which case the ultrasound is used in a similar manner to inspect the sleeve/tube plate weld. an electromagnetic transducer may be used to generate the ultrasound. The ultrasonic head comprising the crystal and an acoustic baffle is mounted on a Perspex (RTM) rod which may be rotated by a stepping motor. Echo signals from the region of deterioration may be isolated by use of a time gate in the receiver. The device primarily detects circumferentially orientated cracks, and may be used in heat exchangers in nuclear power plants. (author)

  18. The in-service inspection of coated steel welds using Eddy-Current Techniques

    International Nuclear Information System (INIS)

    Traditionally surface crack detection in coated Ferritic Steel Welds with Eddy-Current Techniques has been difficult due to the change in material properties in the Heat Affected Zone. These typically produce signals larger than crack signals. Sophisticated probe design and construction, combined with modern electronic equipment, have largely overcome the traditional problems and now enable the advantages of Eddy-Current Techniques to be applied to In-Service Inspection of Coated Ferritic Steel Structures in the as-welded conditions. Specifically, the advantage of the technique is that under quantifiable conditions an inspection may now be carried out through corrosion protection systems. It is the intention of this paper to review the current information available, establish the limiting parameters of the technique and detail the practical experiments conducted to determine the extent of the limiting parameters. The results of these experiments are detailed. Having determined the limiting factors, outline testing procedures have been established together with relative sensitivity settings.

  19. The story of laser brazing technology

    Science.gov (United States)

    Hoffmann, Peter; Dierken, Roland

    2012-03-01

    This article gives an overview on the development of laser brazing technology as a new joining technique for car body production. The story starts with fundamental research work at German institutes in 1993, continues with the first implementations in automobile production in 1998, gives examples of applications since then and ends with an outlook. Laser brazing adapted design of joints and boundary conditions for a safe processing are discussed. Besides a better understanding for the sensitivity of the process against joint irregularities and misalignment, the key to successful launch was an advanced system technology. Different working heads equipped with wire feeding device, seam tracking system or tactile sensors for an automated teaching are presented in this paper. Novel laser heads providing a two beam technology will allow improved penetration depth of the filler wire and a more ecological processing by means of energy consumption.

  20. Laser fusion-brazing of aluminum alloy to galvanized steel with pure Al filler powder

    Science.gov (United States)

    Liu, Jia; Jiang, Shichun; Shi, Yan; Kuang, Yulin; Huang, Genzhe; Zhang, Hong

    2015-03-01

    The fusion-brazing connection of the dissimilar metal 5052 aluminum alloy/ST07Z steel was achieved by using the Nd:YAG laser with pure Al filler powder, and the effects of the laser power and powder feeding speed on the formation and mechanical properties of the resultant joints were investigated. The experimental results show that melting-brazing connection of 5052 aluminum alloy/galvanized steel can be successfully achieved, and the zinc plating layer has played the role of flux, assuring the brazing properties. The intermetallic compound layer was generated on the welded brazing interface. The joint exhibited a shear strength of 174 N/mm if the thickness of the intermetallic layer at the interface is about 6-7 μm.

  1. Studies on partially melted zone in aluminium-copper alloy welds-effect of techniques and prior thermal temper

    Energy Technology Data Exchange (ETDEWEB)

    Rao, K. Srinivasa [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India)]. E-mail: arunaraok@yahoo.com; Reddy, G. Madhusudan [Defense Metallurgical Research Laboratory, Hyderabad 500258 (India); Rao, K. Prasad [Department of Metallurgical and Materials Engineering, Indian Institute of Technology Madras, Chennai 600036 (India)

    2005-08-25

    Partially melted zone (PMZ) of aluminium alloy welds is an important region and requires careful attention. This is mainly because PMZ in these materials is weak link in the weldments and is significantly affected by welding parameters. Microstructure changes in PMZ are related not only to welding heat input and techniques, but also depend on the initial thermal history of alloy (for example, whether it is in T6 or T87 condition etc.). Interestingly, not many detailed studies were available in this respect. In the present work, effect of prior thermal temper and welding techniques mainly continuous and pulsed current gas tungsten arc welding (GTAW) on the PMZ behaviour of AA2219 alloy was studied. Susceptibility to liquation was found to be high in T6 temper of AA2219 alloy than in T87. Pulsed current technique was found to improve the resistance to the susceptibility to liquation in PMZ.

  2. Characterisation of Ga-coated and Ga-brazed aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Ferchaud, E. [Universite de Nantes, Polytech' Nantes, Laboratoire Genie des Materiaux et Procedes Associes, Rue Christian Pauc, 44306 Nantes Cedex 3 (France); Christien, F., E-mail: frederic.christien@univ-nantes.fr [Universite de Nantes, Polytech' Nantes, Laboratoire Genie des Materiaux et Procedes Associes, Rue Christian Pauc, 44306 Nantes Cedex 3 (France); Barnier, V. [Ecole Nationale Superieure des Mines, MPI, CNRS UMR5146, Centre SMS, 158 Cours Fauriel, 42023 Saint Etienne (France); Paillard, P. [Universite de Nantes, Polytech' Nantes, Laboratoire Genie des Materiaux et Procedes Associes, Rue Christian Pauc, 44306 Nantes Cedex 3 (France)

    2012-05-15

    This work is devoted to the brazing of aluminium using liquid gallium. Gallium was deposited on aluminium samples at {approx} 50 Degree-Sign C using a liquid gallium 'polishing' technique. Brazing was undertaken for 30 min at 500 Degree-Sign C in air. EDS (Energy Dispersive X-ray Spectroscopy) and AES (Auger Electron Spectroscopy) characterisation of Ga-coated samples has shown that the Ga surface layer thickness is of ten (or a few tens of) nanometres. Furthermore, aluminium oxide layer (Al{sub 2}O{sub 3}) was shown to be 'descaled' during Ga deposition, which ensures good conditions for further brazing. Cross-section examination of Ga-coated samples shows that liquid gallium penetrates into the aluminium grain boundaries during deposition. The thickness of the grain boundary gallium film was measured using an original EDS technique and is found to be of a few tens of nanometres. The depth of gallium grain boundary penetration is about 300 {mu}m at the deposition temperature. The fracture stress of the brazed joints was measured from tensile tests and was determined to be 33 MPa. Cross-section examination of brazed joints shows that gallium has fully dissolved into the bulk and that the joint is really autogenous. - Highlights: Black-Right-Pointing-Pointer Aluminium can be brazed using liquid gallium deposited by a 'polishing' technique. Black-Right-Pointing-Pointer The aluminium oxide layer is 'descaled' during liquid Ga 'polishing' deposition. Black-Right-Pointing-Pointer EDS can be used for determination of surface and grain boundary Ga film thickness. Black-Right-Pointing-Pointer The surface and grain boundary Ga film thickness is of a few tens of nm. Black-Right-Pointing-Pointer Surface and grain boundary gallium dissolves in the bulk during brazing.

  3. Remote-welding technique for assembling in-pile IASCC capsule in hot cell

    International Nuclear Information System (INIS)

    In order to investigate behavior of the irradiation assisted stress corrosion cracking (IASCC) caused by the simultaneous effects of neutron irradiation and high temperature water environment in such a light water reactor (LWR), it is necessary to perform crack growth tests in an in-pile IASCC capsule irradiated in the Japan Materials Testing Reactor (JMTR). The development of the remote-welding technique is essential for remotely assembling the in-pile IASCC capsule installing the pre-irradiated CT specimens. This report describes a new remote-welding machine developed for assembling the in-pile IASCC capsule. The remote-welding technique that the capsule tube is rotated light under the fixed torch was applied to the machine for the welding of thick and large-diameter tubes. The assembly work of four in-pile IASCC capsules having pre-irradiated CT specimens in the hot cell was succeeded for performing the crack growth test under the neutron irradiation in JMTR. The irradiation test of two capsules has been already finished in JMTR without problems. (author)

  4. Joining of metal bars by a new process of transformation-diffusion brazing

    Institute of Scientific and Technical Information of China (English)

    Zhang Guifeng; Zhang Jianxun; Pei Yi

    2006-01-01

    Within the bonded interface of metal bars joint produced by conventional solid state bonding process (such as flash welding, resistance butt welding, friction welding and so on ), the inclusions are often present, which degrade the ductility of joint. A new process of transformation-diffusion brazing is proposed, in which an amorphous foil containing melting point depressant is preplaced between the interfaces to be joined, and the assembly is repeatedly heated/cooled without holding time at peak temperature. A low carbon steel bars, BNi-2 amorphous foil and resistance butt welding machine were used. The results show that surface contamination can be disrupted by the dissolution of base metal into molten interlayer in comparison with conventional process, and the ductility of joint can be improved by increasing the times of temperature cycles on line. In addition, transformation-diffusion brazing can be done with relatively simple and inexpensive system in comparison with transient liquid phase bonding.

  5. Synthetic Aperture Focusing Technique for the Ultrasonic Evaluation of Friction Stir Welds

    Science.gov (United States)

    Lévesque, D.; Dubourg, L.; Mandache, C.; Kruger, S. E.; Lord, M.; Merati, A.; Jahazi, M.; Monchalin, J.-P.

    2008-02-01

    An ultrasonic technique using numerical focusing and processing is presented in this paper for the detection of different types of flaws in friction stir welds (FSW). The data is acquired using immersion ultrasonic technique or laser ultrasonics, while the Synthetic Aperture Focusing Technique (SAFT) is used for numerical focusing. Measurements on the top and far sides of the weld for both lap and butt joints of thin aluminum sheets are investigated. Discontinuities such as wormholes, hooking, lack of penetration and voids are found to be easily detected. The limit of detectability and a comparison with mechanical properties are discussed. Also, the detection of joint line remnants or kissing bonds due to entrapped oxide layers seems possible in lap joint structures using high frequency laser-ultrasonics.

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

    CERN Document Server

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

    2015-01-01

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

  7. Online monitoring of the laser brazing of titanium overlap joints

    Science.gov (United States)

    Schmitt, R.; Vielhaber, K.; Donst, D.; Klocke, F.

    2007-06-01

    Image processing and thermography for its own are very versatile and established measurement techniques for many years. However, the combination of these two measurement technologies opens a new field of applications. The online monitoring of the laser-brazing of titanium overlap joints is such a new application. The laser brazing process for overlap joining of formed titanium sheets for the production of heat exchangers is presently being investigated at the Fraunhofer IPT. In comparison to conventional furnace brazing the laser brazing technology decreases substantially the heat impact and thus reduces the thermal material damage in the parts due to local selective heating in a laser beam focal spot. Even though the process is stable, errors in the brazing seam such as pores or unacceptable material oxidation can occur. To ensure a high quality an online process monitoring or even process control is necessary. But since the surface remains unchanged during this brazing process no geometrical inspection of the surface can be conducted. Therefore today's quality assurance performs x-ray or destructive testing. This paper demonstrates how the use of thermography in combination with image processing allows a machine integrated online monitoring of the laser brazing process. First the basic principals are presented which cover the fields of heat coupling, heat transmission and heat distribution as well as the temperature emission of light and the spectral properties of the laser beam shaping optic and so lead to the optical set-up. Then analysis algorithms are derived which characterize the process, detect process failures and make a seam tracking possible.

  8. MICROSTRUCTURE AND PROPERTIES OF 5A03 AND SUS304 IN TRANSITIONAL BRAZING

    Institute of Scientific and Technical Information of China (English)

    Lu Xueqin; Yang Shanglei; Wu Yixiong

    2005-01-01

    Stainless steel is so different from aluminum alloys in physical and chemical characters.When they are welded directly, there tend to be Al-Fe brittle compounds on the joint. This paper investigates the processing performance, interface microstructures and mechanical properties of aluminum alloys/stainless steel by way of brazing after brush plating a Ni/Cu transitional layer on stainless steel. After the joints are brazed with Al-Si-Cu-Mg~Zn foil brazing filler metal on different brazing parameters, both the mechanical properties and the microstructures are satisfactory for application.And the influence of the brazing parameters on bonding quality of the brazed joints is discussed in detail. The results reveal that no brittle Al-Fe intermetallic Compound is found in the interfaces. The Ni/Cu electroplating layer effectively hinders the diffusion of Fe atoms from SUS304 to 5A03.Though a little AlCu3 brittle compound is produced, its quantity is too small to affect the strength of the joint.

  9. 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.

  10. The effect of reconditioning techniques by welding on the quality of deposits on crankshafts, case study SMAW

    Science.gov (United States)

    Chivu, O. R.; Cicic, D. T.; Rontescu, C.; Vasile, I. M.; Petriceanu, C.

    2015-11-01

    Currently, we are searching for a range of solutions for repairing the crankshafts that had snapped during operation. The paper deals with the extension of the two methods for reconditioning by welding in the energy industry in the field of repairing the crankshafts in the automotive industry. The results obtained through the application of methods for reconditioning Weld Toe Tempering Technique and filling layers of sidings, which was used as a welding procedure SMAW. Qualitative and quantitative comparisons between the results of the two methods based on the criterion of rigidity are carried out.

  11. Strength of vacuum brazed joints for repair; Haallfasthet hos reparationer utfoerda med vakuumloedning

    Energy Technology Data Exchange (ETDEWEB)

    Berglin, Leif [Siemens Industrial Turbomachinery AB, Finspaang (Sweden)

    2005-04-01

    Strength data are missing for braze joints. Repaired components cannot fully make use of the strength of the braze, and lifetime will be underestimated. The goal of the project was to generate material data to be able to prolong the lifetime of the components. Two different material combinations were tested, 12% Chromium steel brazed with BNi-2, and a nickel base alloy, IN792 brazed with BNi-5. Tensile testing at room temperature and elevated temperature was performed in the project. Target group is purchasers and suppliers of repaired components. A tensile test specimen with butt joint was developed in the project. The used test specimen worked well for the 12% Chromium steel. The results from testing show that proof stress and tensile strength are strongly depending on the joint gap, particularly at room temperature. High strength, close to base material strength, was achieved with joint gaps smaller than 50{mu}m. For wider joint gaps, strength was lower. Strength was approximately 25% of base material strength for joint gaps over 100{mu}m. The results can be explained by changes in microstructure. Joint gaps wider than 50{mu}m showed evidence of two-phase structure. At 500 deg C, the results also showed a connection between joint gap, microstructure and strength. The generated strength data can be used for calculations of lifetime for repaired components. Two different process errors were discovered in the manufacturing process of the brazed IN792 test specimens. The generated material data are therefor erroneous. The reason for this was two manufacturing errors. The tack welding was done with too high heat input. The surfaces of the joint gap became oxidised and the oxide hindered wetting of the braze. The second reason was that the brazing was done without the prescribed hold time at maximum temperature. The melting of the braze was therefor not completed when cooling started. As a result, the strength of the IN792 specimens was low at both temperatures.

  12. Laser beam active brazing of metal ceramic joints

    Science.gov (United States)

    Haferkamp, Heinz; Bach, Friedrich W.; von Alvensleben, Ferdinand; Kreutzburg, K.

    1996-04-01

    The use of engineering ceramics is becoming more and more important. Reasons for this are the specific properties of these materials, such as high strength, corrosion resistance and wear resistance. To apply the advantages of ceramics, joining techniques of metal ceramic parts are required. In this paper, joining of metal ceramic joints by laser beam brazing is presented. This joining technique is characterized by local heat input, and the minimal thermal stress of the brazed components. During the investigations, an Nd:YAG laser and a vacuum chamber were applied. The advantages of Nd:YAG lasers are the simple mechanical construction, and laser beam guidance via quartz glass fibers, which leads to high handling flexibility. In addition, most of the materials show a high absorption rate for this kind of radiation. As materials, ceramic Al2O3 with a purity of 99.4% and metals such as X5CrNi189 and Fe54Ni29Co17 were used. As a filler material, commercially available silver and silver- copper brazes with chemically active elements like titanium were employed. During this study, the brazing wetting behavior and the formation of diffusion layers in dependence on processing parameters were investigated. The results have shown that high brazing qualities can be achieved by means of the laser beam brazing process. Crack-free joining of metal ceramic parts is currently only possible by the use of metals such as Fe54Ni29Co17 because of its low thermal expansion coefficient, which reduces thermal stresses within the joining zone.

  13. Residual strain evaluation of friction stir welded aluminium using neutron diffraction techniques

    International Nuclear Information System (INIS)

    Residual strain evaluations have been performed in the aluminium plate due to friction stir weld (FSW) using neutron diffraction techniques. The sample size was 130 x 50 x 6 mm3 and the welding done along the side of 50 mm. There are two pieces of samples were evaluated with variations of feeding rate, namely 13 and 7.3 mm/ s. Welding performed on the both surface of the sample using 18 mm in diameter and 4 mm length and tip diameter of steering tool. Residual strain measurements performed by using DN1 installed at beam tube number 6 of RSG-GAS Serpong. The residual strain measurement had been performed on Transverse and Normal direction using hkl plane of (220) with a scattering angle around 79 degrees. Incident slit and the detector used is 2 x 2 and 2 x 10 mm2, respectively. Residual tensile strains was observed in both samples in the direction. Normal to the largest value is 1200 μm/ m on samples with a feeding speed 13 mm/ s, whereas the sample with a feeding speed of 7.3 mm/ s is 800 μm/ m. Compression residual strain was found in both samples in Transverse direction, with the largest value of 900 and 700 μm/ m with feeding speed 13 mm/ s and 7.3 mm/ s, respectively. (Author)

  14. Manufacture of micro fluidic devices by laser welding using thermal transfer printing techniques

    Science.gov (United States)

    Klein, R.; Klein, K. F.; Tobisch, T.; Thoelken, D.; Belz, M.

    2016-03-01

    Micro-fluidic devices are widely used today in the areas of medical diagnostics and drug research, as well as for applications within the process, electronics and chemical industry. Microliters of fluids or single cell to cell interactions can be conveniently analyzed with such devices using fluorescence imaging, phase contrast microscopy or spectroscopic techniques. Typical micro-fluidic devices consist of a thermoplastic base component with chambers and channels covered by a hermetic fluid and gas tight sealed lid component. Both components are usually from the same or similar thermoplastic material. Different mechanical, adhesive or thermal joining processes can be used to assemble base component and lid. Today, laser beam welding shows the potential to become a novel manufacturing opportunity for midsize and large scale production of micro-fluidic devices resulting in excellent processing quality by localized heat input and low thermal stress to the device during processing. For laser welding, optical absorption of the resin and laser wavelength has to be matched for proper joining. This paper will focus on a new approach to prepare micro-fluidic channels in such devices using a thermal transfer printing process, where an optical absorbing layer absorbs the laser energy. Advantages of this process will be discussed in combination with laser welding of optical transparent micro-fluidic devices.

  15. Microstructure and Mechanical Properties of Plasma Arc Brazed AISI 304L Stainless Steel and Galvanized Steel Plates

    Science.gov (United States)

    Jin, Yajuan; Li, Ruifeng; Yu, Zhishui; Wang, Yu

    2016-04-01

    Plasma arc brazing is used to join the AISI 304L stainless steel and galvanized steel plate butt joints with the CuSi3Mn1 filler wire. The effect of parameters on weld surface appearance, interfacial microstructure, and composition distribution in the joint was studied. The microhardness and mechanical tests were conducted to determine the mechanical properties of the welded specimens. The results indicated that good appearance, bead shape, and sufficient metallurgical bonding could be obtained when the brazing process was performed with a wire feeding speed of 0.8 m/min, plasma gas flow rate of 3.0 l/min, welding current of 100 A, and welding speed of 27 cm/min. During plasma arc brazing process, the top corner of the stainless steel and galvanized steel plate were heated and melted, and the melted quantity of stainless steel was much more than that of the galvanized steel due to the thermal conductivity coefficient difference between the dissimilar materials. The microhardness test results shows that the microhardness value gradually increased from the side of the galvanized steel to the stainless steel in the joint, and it is good for improving the mechanical properties of joint. The tensile strength was a little higher than that of the brazing filler, and the fracture position of weld joint was at the base metal of galvanized steel plate.

  16. Induction brazing of complex joints

    DEFF Research Database (Denmark)

    Henningsen, Poul; Zhang, Wenqi; Bay, Niels

    2003-01-01

    Induction brazing is a fast and appropriate method for industrial joining of complex geometries and metal combinations. In all types of brazing processes it is important to heat the joint interface of the two materials to the same, high temperature. If one of the specimens is warmer than the other...... materials has large influence on the heating time and temperature distribution in induction heating. In order to ensure high and uniform temperature distribution near the interface of a joint between dissimilar materials the precise coil geometry and position is of great importance. The present paper...... presents a combined numerical and experimental method for fast determination of appropriate coil geometry and position in induction brazing tube-to-plate joints of different ratios between tube and plate thickness and different combinations of the materials stainless steel, brass and copper. The method has...

  17. Optimization of Welding Parameters of Submerged Arc Welding Using Analytic Hierarchy Process (AHP) Based on Taguchi Technique

    Science.gov (United States)

    Sarkar, A.; Roy, J.; Majumder, A.; Saha, S. C.

    2014-04-01

    The present paper reports a new procedure using an analytic hierarchy process (AHP) based Taguchi method for the selection of the best welding parameters to fabricate submerged arc welding of plain carbon steel. Selection of best welding parameters is an unstructured decision problem involving process parameters for multiple weldments. In the present investigation, three process parameter variables i.e. wire feed rate (Wf), stick out (So) and traverse speed (Ts) and the three response parameters i.e. penetration, bead width and bead reinforcement have been considered. The objective of the present work is thus to improve the quality of the welded elements by using AHP analysis based Taguchi method. Taguchi L16 orthogonal array is used to perform with less number of experimental runs. Taguchi approach is insufficient to solve a multi response optimization problem. In order to overcome this limitation, a multi criteria decision making method, AHP is applied in the present study. The optimal condition to have a quality weld (i.e. bead geometry) is found at 210 mm/min of wire feed rate, 15 mm of stick out and 0.75 m/min of traverse speed and also observed that the effect of wire feed rate on the overall bead geometry properties is more significant than other welding parameters. Finally, a confirmatory test has been carried out to verify the optimal setting so obtained.

  18. Fiber laser welding of dual-phase galvanized sheet steel (DP590): traditional analysis and new quality assessment techniques

    Science.gov (United States)

    Miller, Stephanie; Pfeif, Erik; Kazakov, Andrei; Baumann, Esther; Dowell, Marla

    2016-03-01

    Laser welding has many advantages over traditional joining methods, yet remains underutilized. NIST has undertaken an ambitious initiative to improve predictions of weldability, reliability, and performance of laser welds. This study investigates butt welding of galvanized and ungalvanized dual-phase automotive sheet steels (DP 590) using a 10 kW commercial fiber laser system. Parameter development work, hardness profiles, microstructural characterization, and optical profilometry results are presented. Sound welding was accomplished in a laser power range of 2.0 kW to 4.5 kW and travel speed of 2000 mm/min to 5000 mm/min. Vickers hardness ranged from approximately 2 GPa to 4 GPa across the welds, with limited evidence of heat affected zone softening. Decreased hardness across the heat affected zone directly correlated to the appearance of ferrite. A technique was developed to non-destructively evaluate weld quality based on geometrical criteria. Weld face profilometry data were compared between light optical, metallographic sample, and frequency-modulated continuous-wave laser detection and ranging (FMCW LADAR) methods.

  19. Development of Zn50 Brazing Alloy for Joining Mild Steel to Mild Steel (SAE1018

    Directory of Open Access Journals (Sweden)

    S.C. Nwigbo

    2014-09-01

    Full Text Available This work has developed new brazing alloys for joining mild steel to mild steel (SAE1018 at a lower temperature. The alloys blends and error analysis were done by experimental design software (Design Expert 8.0.7.1. Design of experiments was done by Scheffe quadratic mixture method. The liquidus temperatures were predicted by calculation of phase diagrams of the alloying metals. The brazing alloys were produced by gravity technique and melted using silicon carbide graphite crucible. The quality of the brazing alloys was analyzed by optical microscopy (OM, atomic absorption spectroscopy (AAS and fourier transform infrared spectroscopy (FT-IR. Brazed joints were produced by torch method with a commercial flux. Brazing temperatures (liquidus were tracked by a digital infrared/laser pyrometer. Some mechanical properties studied were tensile strength and hardness. Finally, brazed joints produced from the developed brazing alloys were compared to that produced from muntz brass. Six (6 brazing alloys were successfully developed. Zinc and manganese were the main components, to which were added; 3 to 4 %wt silver and 11 to15 %wt modifying element. The microstructure showed a typical eutectic structure with zinc-rich phase distributed uniformly in the matrix with a combination of different sizes of dendrite, rounded blocks of compounds and hypoeutectic structures. AAS results indicated minimal out-gassing of zinc and FT-IR results indicated very low presence of atmospheric gas. The range of brazing temperature for best results was recorded from 690.90 to 735.10 0C. The joints produced from the developed brazing alloys had acceptable strengths with improved stress-strain behaviour compared to muntz brass.

  20. Interfacial reaction product and mechanical properties of the electron beam brazed K465 Ni-based superalloy joints

    Institute of Scientific and Technical Information of China (English)

    Wang Gang; Zhang Binggang; He Jingshan; Feng Jicai; Wu Yingjie

    2008-01-01

    Ni-based superalloy K465 is brazed with BNi-2 filler metal by vacuum electron beam brazing (VEBB). In process of VEBB, effects of processing primary parameters on shear strength of joints are investigated. Microstructure of the brazed joint with BNi-2 filler metal is studied by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results show that the structure of brazed seam consists of a large amount of Ni-based γ solid solution, Ni3Al (γ′), Ni3B, WB, CrB, and a small quantity of WC, NbC. The maximum shear strength of the joint is 398 MPa when the beam current of welding is 2.6 mA, heating time is 480 s and focused current is 1 800 mA.

  1. Development of depth measurement technique for a flaw in weld area of stainless steel with twin matrix array ultrasonic probe

    International Nuclear Information System (INIS)

    A twin matrix array transducer to make possible to detect and measure a flaw with test direction through weld of austenitic stainless steel has been developed. Each transducer performs as transmitter and receiver and has 2 lines and 16 columns array elements respectively. With this transducer depth measurement tests for cracks by stress corrosion cracking (SCC) and fatigue on austenitic stainless steel weld pipe specimens have been carried out. As the results: (1) Corner echoes and tip echoes from SCCs and fatigue cracks could be detected with test direction through the weld of the 25 mm thickness stainless steel pipe specimens. (2) The depth measurements through the weld and in base metal corresponded well. Therefore we have evaluated that the twin matrix array transducer mode possible to measure flaw depth with both the test direction and was effective ultrasonic testing technique to be able to estimate and evaluate flaw depth with more accuracy and reliability. (author)

  2. Development of welding technique between PNC-FMS wrapper tube and SUS316 steel. 2. Evaluation of welding technique for real size wrapper tube

    International Nuclear Information System (INIS)

    It is necessary to carry out the welding with the austenitic stainless steel in order to apply the high strength Ferritic/Martensitic steel (PNC-FMS) with superior resistance to swelling as wrapper tube in 'Joyo' and Monju'. If the δ ferrite phase would be formed at heat affected zone (HAZ) in welding between PNC-FMS wrapper tube and SUS316 steel, toughness degradation would be suspected. In this study, as the method in which δ ferrite was not formed at the weld zone, the elimination of δ ferrite by the heat treatment was examined, and the heat treatment condition was optimized. The possibility and realization of manufacturing the PNC-FMS wrapper tube with joint structure to SUS316 short length tube were also evaluated. The results obtained are summarized as follows. (1) δ ferrite phase in welding part is successfully eliminated by carrying out the normalizing processing over 1050degC x 10 min as a post-welding heat treatment. (2) As a fabrication process, the following process was selected from the viewpoint of practical application. TIG welding of PNC-FMS round tube and SUS316 round tube → Post-welding heat treatment → Cold drawing (hexagonal tube) → Normalizing, tempering → The dimension adjustment by the cold drawing. (3) As a result of investigation of microstructure and mechanical properties of the weld zone of produced wrapper tube, the satisfied performance of the joint was confirmed. (author)

  3. Building Quakes: Detection of Weld Fractures in Buildings using High-Frequency Seismic Techniques

    Science.gov (United States)

    Heckman, V.; Kohler, M. D.; Heaton, T. H.

    2009-12-01

    Catastrophic fracture of welded beam-column connections in buildings was observed in the Northridge and Kobe earthquakes. Despite the structural importance of such connections, it can be difficult to locate damage in structural members underneath superficial building features. We have developed a novel technique to locate fracturing welds in buildings in real time using high-frequency information from seismograms. Numerical and experimental methods were used to investigate an approach for detecting the brittle fracture of welds of beam-column connections in instrumented steel moment-frame buildings through the use of time-reversed Green’s functions and wave propagation reciprocity. The approach makes use of a prerecorded catalogue of Green’s functions for an instrumented building to detect high-frequency failure events in the building during a later earthquake by screening continuous data for the presence of one or more of the events. This was explored experimentally by comparing structural responses of a small-scale laboratory structure under a variety of loading conditions. Experimentation was conducted on a polyvinyl chloride frame model structure with data recorded at a sample rate of 2000 Hz using piezoelectric accelerometers and a 24-bit digitizer. Green’s functions were obtained by applying impulsive force loads at various locations along the structure with a rubber-tipped force transducer hammer. We performed a blind test using cross-correlation techniques to determine if it was possible to use the catalogue of Green’s functions to pinpoint the absolute times and locations of subsequent, induced failure events in the structure. A finite-element method was used to simulate the response of the model structure to various source mechanisms in order to determine the types of elastic waves that were produced as well as to obtain a general understanding of the structural response to localized loading and fracture.

  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. 铝-镀锌钢板异种金属Pulsed DE-MIG熔钎焊方法研究%Pulsed DE-MIG brazing-welding method of aluminum-galvanized steel dissimilar metals

    Institute of Scientific and Technical Information of China (English)

    顾玉芬; 邵玲; 石玗; 黄健康

    2014-01-01

    A new, high efficiency and low heat input method of Pulsed DE-MIG was put forward to control welding heat input precisely and growth of intermetallic compounds in interface of aluminum-steel. Pulsed DE-MIG process parameters were optimized by plate welding of aluminum alloy welding wire ER5356 welded on galvanized steel. The total current of welding wire remained constant, and Pulsed DE-MIG of aluminum-galvanized steel dissimilar metals was carried out at different Pulsed DE-MIG welding parameters. It indicated that the weld seam width decreased significantly but bead height increased obviously when bypass current increased gradually. OM, SEM and EDS were adopted to observe and characterize the interface microstructures of the joints. Two intermetallic compounds layers of Fe2 Al5 and FeAl3 formed along the interface. When the heat input of base metal was large, many FeAl3 precipicated, and when the heat input of base metal was decreased gradually, the amount of FeAl3 decreased until without FeAl3 .%为精确控制焊接热输入,从而控制铝钢异种金属界面区金属间化合物生长,提出一种新型高效低热输入的脉冲旁路耦合电弧MIG焊(Pulsed DE-MIG)方法,用ER5356铝合金焊丝在镀锌钢板上利用平板堆焊实验对工艺参数进行优化。在焊丝总电流保持不变,不同的Pulsed DE-MIG焊接参数下焊接,结果表明随着旁路电流的增大,焊缝宽度显著变小,且焊缝堆高明显变高。采用OM、SEM、EDS等测试手段观察和分析连接界面区的微观组织,发现在连接界面区形成Fe2 Al5、FeAl3金属间化合物层,且母材热输入大时,FeAl3析出得多,随着母材热输入的减小,FeAl3析出逐步减少直至FeAl3无析出。

  6. High quality joining techniques: in-process assurance (IPA) welding system

    International Nuclear Information System (INIS)

    On July 1, 1995, the Product Liability Law was enforced, and in industrial world, further reliability has been demanded. Recently, accompanying the progress of electronics, the proportion taken by automatic welders and robots increased in welding. By memorizing proper welding conditions, the welding from initial to final passes can be done fully automatically. Also feedback mechanism was equipped to mechanized welders, and the in-process control has become to be feasible. The way of thinking on confirming in process welding quality in arc welding is explained. IPA welding system utilizes the multi-media collecting images and sound, samples the change of welding conditions and the state of arc on a same screen, and monitors the deviation from the range of proper welding conditions. At the time of abnormality, inspector or a computer carries out image diagnosis and welding control, and the system indicates the soundness of welded parts. The basic concept and the flow chart of this system are shown. The experiment of applying the system to arc welding is reported. The correlation of welding phenomena and welding conditions is examined. (K.I.)

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-01-15

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

  8. Simulation based analysis of laser beam brazing

    Science.gov (United States)

    Dobler, Michael; Wiethop, Philipp; Schmid, Daniel; Schmidt, Michael

    2016-03-01

    Laser beam brazing is a well-established joining technology in car body manufacturing with main applications in the joining of divided tailgates and the joining of roof and side panels. A key advantage of laser brazed joints is the seam's visual quality which satisfies highest requirements. However, the laser beam brazing process is very complex and process dynamics are only partially understood. In order to gain deeper knowledge of the laser beam brazing process, to determine optimal process parameters and to test process variants, a transient three-dimensional simulation model of laser beam brazing is developed. This model takes into account energy input, heat transfer as well as fluid and wetting dynamics that lead to the formation of the brazing seam. A validation of the simulation model is performed by metallographic analysis and thermocouple measurements for different parameter sets of the brazing process. These results show that the multi-physical simulation model not only can be used to gain insight into the laser brazing process but also offers the possibility of process optimization in industrial applications. The model's capabilities in determining optimal process parameters are exemplarily shown for the laser power. Small deviations in the energy input can affect the brazing results significantly. Therefore, the simulation model is used to analyze the effect of the lateral laser beam position on the energy input and the resulting brazing seam.

  9. Successful development of innovative fabrication technique based on laser welding, for superconducting RF cavities - results and path ahead

    International Nuclear Information System (INIS)

    Superconducting radio frequency (SCRF) cavities are the heart of any particle accelerator based on SCRF technology. All over the world, efforts are being made to develop a technique which can bring down the cost and time of fabrication of these cavities. The present day fabrication method of SCRF cavities uses Electron beam welding (EBW) technique. The cavities fabricated by this method turn out to be expensive and take long fabrication time. To overcome such difficulties related with EBW process, an innovative concept for fabrication of SCRF cavities based on laser welding was formulated at RRCAT. International patent application was immediately launched for this work, to protect intellectual property rights of DAE

  10. Applying a nonlinear, pitch-catch, ultrasonic technique for the detection of kissing bonds in friction stir welds.

    Science.gov (United States)

    Delrue, Steven; Tabatabaeipour, Morteza; Hettler, Jan; Van Den Abeele, Koen

    2016-05-01

    Friction stir welding (FSW) is a promising technology for the joining of aluminum alloys and other metallic admixtures that are hard to weld by conventional fusion welding. Although FSW generally provides better fatigue properties than traditional fusion welding methods, fatigue properties are still significantly lower than for the base material. Apart from voids, kissing bonds for instance, in the form of closed cracks propagating along the interface of the stirred and heat affected zone, are inherent features of the weld and can be considered as one of the main causes of a reduced fatigue life of FSW in comparison to the base material. The main problem with kissing bond defects in FSW, is that they currently are very difficult to detect using existing NDT methods. Besides, in most cases, the defects are not directly accessible from the exposed surface. Therefore, new techniques capable of detecting small kissing bond flaws need to be introduced. In the present paper, a novel and practical approach is introduced based on a nonlinear, single-sided, ultrasonic technique. The proposed inspection technique uses two single element transducers, with the first transducer transmitting an ultrasonic signal that focuses the ultrasonic waves at the bottom side of the sample where cracks are most likely to occur. The large amount of energy at the focus activates the kissing bond, resulting in the generation of nonlinear features in the wave propagation. These nonlinear features are then captured by the second transducer operating in pitch-catch mode, and are analyzed, using pulse inversion, to reveal the presence of a defect. The performance of the proposed nonlinear, pitch-catch technique, is first illustrated using a numerical study of an aluminum sample containing simple, vertically oriented, incipient cracks. Later, the proposed technique is also applied experimentally on a real-life friction stir welded butt joint containing a kissing bond flaw. PMID:26921559

  11. Applying a nonlinear, pitch-catch, ultrasonic technique for the detection of kissing bonds in friction stir welds.

    Science.gov (United States)

    Delrue, Steven; Tabatabaeipour, Morteza; Hettler, Jan; Van Den Abeele, Koen

    2016-05-01

    Friction stir welding (FSW) is a promising technology for the joining of aluminum alloys and other metallic admixtures that are hard to weld by conventional fusion welding. Although FSW generally provides better fatigue properties than traditional fusion welding methods, fatigue properties are still significantly lower than for the base material. Apart from voids, kissing bonds for instance, in the form of closed cracks propagating along the interface of the stirred and heat affected zone, are inherent features of the weld and can be considered as one of the main causes of a reduced fatigue life of FSW in comparison to the base material. The main problem with kissing bond defects in FSW, is that they currently are very difficult to detect using existing NDT methods. Besides, in most cases, the defects are not directly accessible from the exposed surface. Therefore, new techniques capable of detecting small kissing bond flaws need to be introduced. In the present paper, a novel and practical approach is introduced based on a nonlinear, single-sided, ultrasonic technique. The proposed inspection technique uses two single element transducers, with the first transducer transmitting an ultrasonic signal that focuses the ultrasonic waves at the bottom side of the sample where cracks are most likely to occur. The large amount of energy at the focus activates the kissing bond, resulting in the generation of nonlinear features in the wave propagation. These nonlinear features are then captured by the second transducer operating in pitch-catch mode, and are analyzed, using pulse inversion, to reveal the presence of a defect. The performance of the proposed nonlinear, pitch-catch technique, is first illustrated using a numerical study of an aluminum sample containing simple, vertically oriented, incipient cracks. Later, the proposed technique is also applied experimentally on a real-life friction stir welded butt joint containing a kissing bond flaw.

  12. Field installed brazed thermocouple feedthroughs for high vacuum experiments

    Science.gov (United States)

    Anderson, P. M.; Messick, C.

    1983-12-01

    In order to reduce the occurrence of vacuum leaks and to increase the availability of the DIII vacuum vessel for experimental operation, effort was applied to developing a vacuum-tight brazed feedthrough system for sheathed thermocouples, stainless steel sheathed conductor cables and tubes for cooling fluids. This brazed technique is a replacement for elastomer O ring sealed feedthroughs that have proven vulnerable to leaks caused by thermal cycling, etc. To date, about 200 feedthroughs were used. Up to 91 were grouped on a single conflat flange mounted in a bulkhead connector configuration which facilitates installation and removal. Investigation was required to select a suitable braze alloy, flux and installation procedure. Braze alloy selection was challenging since the alloy was required to have: (1) melting temperature in excess of the 250 C (482 F) bakeout temperature; (2) no high vapor pressure elements; (3) good wetting properties when used in air with acceptable flux; and (4) good wettability to 300 series stainless steel and Inconel.

  13. 1Cr18Ni9Ti/6A02 Dissimilar Metal Braze Welding Head Structure Analysis%1Cr18Ni9Ti/6A02异种金属钎焊接头结构分析

    Institute of Scientific and Technical Information of China (English)

    孙秀京; 马广超; 马丽翠; 孔兆财; 范波; 柳玲; 陈志凯

    2014-01-01

    The morphology and the microstruc-ture of 1Cr18Ni9Ti stainless steel and 6A02 aluminum alloy dissimilar metal joints obtained by the crucible fur-nace brazing process are analysis in this paper. The macro morphology and the microstructure characteristics of the joints were expounded through metallographic examina-tion;Scanning electron microscopy is used to observe the microstructure and measure the energy spectrum, thus the steel/aluminum dissimilar metal interface layer structure is further analyzed, and the typical defect of the joint is de-scribed and analyzed.%本文针对采用坩锅炉钎焊工艺获得的1Cr18Ni9Ti不锈钢与6A02铝合金异种金属钎焊接头进行了接头形貌及微观组织分析。通过金相检查的方法阐述了接头宏观形貌及界面组织特点;使用扫描电镜进行了高倍组织观察及能谱测量,从而进一步分析了钢/铝异种金属界面层结构,并对接头典型缺陷进行了描述和分析。

  14. 爆炸焊接技术研究进展%Research Development of Explosive Welding Technique

    Institute of Scientific and Technical Information of China (English)

    王克鸿; 张德库; 张文军

    2011-01-01

    爆炸焊接是一种通过在金属表面施加可控的爆炸能量以实现金属连接的固态焊接方法.介绍了爆炸焊接的概念和发展历史,并对近几年国内外在爆炸焊接理论、试验和数值模拟以及应用等方面的研究进展进行了综述,提出了未来爆炸焊接技术发展的几个重要方面,并指出今后爆炸焊接技术的研究要着眼于非晶合金以及具有耐高温、耐腐蚀等优异性能材料的研究,以满足人们对材料性能的要求,并展望了爆炸焊接的发展趋势.%Explosion welding (EXW) is one of the joining methods consisting of a solid state welding process in which controlled explosive detonation on the surface of a metal. This paper introduces the conception and the history of the explosive welding technique. And then a bdef summary is given ,which is about the research development of explosive welding in the aspects such as theoretical analysis,trials and numerical simulation ,practical application. Some important aspects about the future development of explosive welding are pointed out. Future research of explosive welding technique shall focus on the development of non-crystal alloy and material with characteristics such as the ability of bearing high temperature and corruption to satisfy the requirement of new property.At last future developments in explosive welding are predicted and criticized in an outlook.

  15. Influence of the brazing parameters on microstructure and mechanical properties of brazed joints of Hastelloy B2 nickel base alloy; Influencia de los parametros de soldeo fuerte en la microestructura y propiedades mecanicas de la union de la aleacion base niquel Hastelloy B2

    Energy Technology Data Exchange (ETDEWEB)

    Sotelo, J. C.; Gonzalez, M.; Porto, E.

    2014-07-01

    A study of the high vacuum brazing process of solid solution strengthened Hastelloy B2 nickel alloy has been done. A first stage of research has focused on the selection of the most appropriate brazing filler metal to the base material and vacuum furnace brazing process. The influence of welding parameters on joint microstructure constituents, relating the microstructure of the joint to its mechanical properties, has been evaluated. Two gaps of 50 and 200 micrometers, and two dwell times at brazing temperature of 10 and 90 minutes were studied. The braze joint mainly consists of the nickel rich matrix, nickel silicide and ternary compounds. Finally, the results of this study have shown the high bond strength for small gaps and increased dwell times of 90 minutes. (Author)

  16. 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.

  17. Filler alloys for brazing in power industries

    International Nuclear Information System (INIS)

    The problem is discussed of using nickel-based high-temperature brazing solders in nuclear power engineering. Different types of brazing solders are compared with regard to brazing and mechanical properties and oxidation resistance. The advantages of nickel-based brazing solders include their melting temperature which is higher by 150 to 200 degC than the melting temperatures of common solders. The effects of different additions on melting temperature are discussed. It is advisable to use the above brazing solders under hydrogen reduction atmosphere at a temperature of -40 down to -75 degC or at a pressure of 10-3 down to 10-4 Pa. Currently manufactured nickel-based brazing solders may be used at a temperature of up to 1150 degC. (J.B.)

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

    Science.gov (United States)

    Sham, Kin-Ling

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

  19. Possible fabrication techniques and welding specifications for the external cylinder of the CMS coil

    CERN Document Server

    Castoldi, M; Desirelli, Alberto; Favre, G; Losasso, M; Sequeira-Lopes-Tavares, S; Sgobba, Stefano; Tardy, T; Levesy, B; Reytier, M

    2000-01-01

    The Compact Muon Solenoid (CMS) is one of the experiments, which are being designed in the framework of the Large Hadron Collider (LHC) project at CERN. The design field of the CMS magnet is 4 T, the magnetic length is 12.5 m and the free aperture is 6 m in diameter. This is achieved with a 4 layer and 5 module superconducting Al- stabilized coil energized at a nominal current of 20 kA at 4.5 K. In the CMS coil the structural function is ensured, unlike in other existing Al-stabilized thin solenoids, both by the Al-alloy reinforced conductor and the external cylinder. The calculated stress level in the cylinder at operating conditions is particularly severe. In this paper the different possible fabrication techniques are assessed and compared and a possible welding specification for this component is given. (9 refs).

  20. Interface structure and mechanical property of aluminum cooler vacuum brazing joint

    Institute of Scientific and Technical Information of China (English)

    FENG Tao; LOU Song-nian; WU Lu-hai; LI Ya-jiang

    2006-01-01

    A kind of aluminum cooler was manufactured by means of vacuum brazing technique, and the cooler was examined by hydraulic pressure test. The result indicates that the test pressure of the cooler can reach 15 MPa. The fracture of the brazing joint belongs to the mixture type. There are secondary cracks, dimples, cleavage plane and grain-boundary features on the failure surface.The cracking process of aluminum cooler is as follows. The cracks are initiated on the interface, then expand under sub-critical state.When the stress on the remained zone reaches the maximum notch tensile strength of the brazing joint or the crack length reaches the critical value that the brazing joint fracture toughness property permits, the cooler will break sharply.

  1. Investigation on laser brazing AA6056 Al alloy to XC18 low-carbon steel

    Institute of Scientific and Technical Information of China (English)

    Jianjun Ding; Feiqun Li; Feng Qu; Patrice Peyre; Remy Fabbro

    2005-01-01

    @@ Based on the studies of influence of YAG laser heating conditions for Al alloy melt and steel on wettability,the mechanics of the laser overlap braze welding of 6056 Al and XC18 steel sheet has been investigated.Under the temperature range which is above the melting point of the Al alloy and below the melting point of the steel, two dissimilar metals can be joined by means of laser braze welding. There is no crack observed in the joining area, i.e. Al-Fe intermetallic phase (Fe3Al/FeAl/FeAl3/Fe2Al5) layer formed by solution and diffusion between liquid-solid interface. The temperature range can be defined as the process temperatures of laser braze welding of Al-Fe materials. Selecting a higher laser heating temperature can improve the wettability of Al melt to steel surface, but the intermetallic phase layer is also thicker. When the laser heating temperature is so high that the joining surface of steel is melted, there is a crack trend in the joining area.

  2. Processes, Techniques, and Successes in Welding the Dry Shielded Canisters of the TMI-2 Reactor Core Debris

    International Nuclear Information System (INIS)

    The Idaho National Engineering and Environmental Laboratory (INEEL) is operated by Bechtel-BWXT Idaho LLC (BBWI), which recently completed a very successful $100 million Three-Mile Island-2 (TMI-2) program for the Department of Energy (DOE). This complex and challenging program used an integrated multidisciplinary team approach that loaded, welded, and transported an unprecedented 25 dry shielded canisters (DSC) in seven months, and did so ahead of schedule. The program moved over 340 canisters of TMI-2 core debris that had been in wet storage into a dry storage facility at the INEEL. The main thrust of this paper is relating the innovations, techniques, approaches, and lessons learned associated to welding of the DSC's. This paper shows the synergism of elements to meet program success and shares these lessons learned that will facilitate success with welding of dry shielded canisters in other DOE complex dry storage programs

  3. Residual stress in a laser welded EUROFER blanket module assembly using non-destructive neutron diffraction techniques

    Energy Technology Data Exchange (ETDEWEB)

    Hughes, D.J., E-mail: d.hughes@warwick.ac.uk [WMG, University of Warwick, Coventry CV4 7AL (United Kingdom); Koukovini-Platia, E. [CERN, CH-1211 Geneva 23 (Switzerland); Heeley, E.L. [Department of Physical Sciences, Open University, Walton Hall, Milton Keynes MK7 6AA (United Kingdom)

    2014-02-15

    Highlights: • Residual stresses were determined in a welded EUROFER blanket assembly with integrated cooling channels. • Good agreement was seen between experimentally determined and predicted stresses. • We show that microstructure changes that occur in EUROFER steels during welding must be considered for residual stress determination. • An experimental route is proposed for validation of predicted stresses in reactor components using non-destructive diffraction techniques. - Abstract: Whilst the structural integrity and lifetime considerations in welded joints for blanket modules can be predicted using finite element software, it is essential to prove the validity of these simulations. This paper provides detailed analysis for the first time, of the residual stress state in a laser-welded sample with integral cooling channels. State-of-the-art non-destructive neutron diffraction was employed to determine the triaxial stress state and to understand microstructural changes around the heat affected zone. Synchrotron X-ray diffraction was used to probe the variation of strain-free lattice reference parameter around the weld zone allowing correction of the neutron measurements. This paper details an important experimental route to validation of predicted stresses in complex safety-critical reactor components for future applications.

  4. Numerical simulation of copper based filler metal droplets spreading under arc brazing

    Institute of Scientific and Technical Information of China (English)

    YU Zhi-shui; LI Rui-feng; QI Kai; ZHOU Fang-ming

    2005-01-01

    The spreading behavior of copper filler metal droplets under arc brazing was studied by numerical simulation method using Surface Evolver software. The mathematical model in which arc pressure force acceleration was added to the droplet microelement as the form of gravity acceleration was used in numerical simulation. Then the 3D filler metal droplet profile for different welding currents was simulated. The results show that the simulation results and the experimental results are in good accordance. And it can be seen that the spreading height decreases and diameter increases with the increasing welding current in an approximate linear relation.

  5. 焊接技术在金属切削刀具中的应用%Welding technique application in metal machining tool

    Institute of Scientific and Technical Information of China (English)

    马庆文

    2012-01-01

      目前我国刀具焊接基本上分为两种:摩擦焊和闪光对焊。本文主要介绍了焊接技术在金属切削刀具中的应用及其在生产加工中相关的知识。%  At present,domestic machining tool welding is basically divided into friction stir welding and flashing butt welding. This paper mainly describes welding technique application in metal machining tool and relevant knowledge for processing.

  6. METHODS FOR BRAZING UNUSUAL METAL COMBINATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Bertossa, Robert C.

    1963-10-15

    A method for vacuum pressure braze cladding is described. Application of the method to Mo-OFHC Cu-type 316L stainlcss steel, Ta cladding on OFHC Cu, Nb with Ni, Ti and Zr on steels, and pure Be brazing to austenitic stalnless steel are discussed. The advantages of vacuumpressure bonding are also discussed. (P.C.H.)

  7. Cold metal transfer welding–brazing of pure titanium TA2 to magnesium alloy AZ31B

    Energy Technology Data Exchange (ETDEWEB)

    Cao, R., E-mail: caorui@lut.cn; Wang, T.; Wang, C.; Feng, Z.; Lin, Q.; Chen, J.H.

    2014-08-25

    Highlights: • Mg–Ti joints can be successfully performed at suitable welding variables by CMT. • Typical brazing–welding joints can be formed for Mg–Ti joint and Ti–Mg joint. • The brazing interface is mainly composed of Ti{sub 3}Al, Mg{sub 17}Al{sub 12} and Mg{sub 0.97}Zn{sub 0.03}. • Elements Al and Zn are crucial to join successfully Mg and Ti base metals. - Abstract: Pure titanium TA2 was joined to Mg AZ31B by cold metal transfer (CMT) welding–brazing method in the form of two lap-shear joints (Mg–Ti joint and Ti–Mg joint) with Mg AZ61 wire. The microstructure of Ti/Mg CMT joints was identified and characterized by means of optical microscopy (OM), scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The mechanical properties of various welding parameters were compared and analyzed. Desired Ti/Mg CMT joints with satisfied weld appearances and mechanical properties were achieved at suitable welding variables. The Ti/Mg CMT joints had dual characteristics of a welding joint at the Mg side and a brazing joint at the Ti side. Moreover, for two joints, the brazing interfaces were composed of an intermetallic compounds (IMCs) layer including Ti{sub 3}Al, Mg{sub 17}Al{sub 12} and Mg{sub 0.97}Zn{sub 0.03} phases. Mg–Ti joint had the higher tensile load of 2.10 kN, and Ti–Mg joint had the tensile load of 1.83 kN.

  8. Residual stress distribution in austenitic stainless steel pipe butt-welded joint measured by neutron diffraction technique

    International Nuclear Information System (INIS)

    Residual stress is inevitable consequence of welding or manufacturing process, which might greatly affect propagation of high-cycle fatigue or SCC crack. In order to evaluate damages due to the crack, it is required to estimate residual stress and to reflect them to the evaluation process as well. The magnitude and distribution of residual stress greatly depend on the individual process of welding or manufacturing, while the accuracy of prediction or measurement is still insufficient. This paper reports the result of residual stress measurement of butt-welded pipe made of austenitic stainless steel. It also intended to improve prediction and measurement techniques concerning to residual stress. The measurement was conducted by neutron diffraction technique employing the diffractometer for residual stress analysis developed by Japan Atomic Energy Agency. The measured results showed typical characteristics of butt-welded pipe both in decline of stress along axial direction and in radial distribution of bending due to axial stress. The measured result agreed qualitatively with the result predicted by the finite element analysis. A quantitative comparison between measured result and analysis showed a shift of the measured stress toward higher tensile. The measured result was also compared with the results by X-ray diffraction and strain-gauge methods to grasp the distinctive results of the methods. (author)

  9. Wear behavior of the surface alloyed AISI 1020 steel with Fe-Nb-B by TIG welding technique

    Science.gov (United States)

    Kilinc, B.; Durmaz, M.; Abakay, E.; Sen, U.; Sen, S.

    2015-03-01

    Weld overlay coatings also known as hardfacing is a method which involves melting of the alloys and solidification for applied coatings. Recently hardfacing by welding has become a commonly used technique for improvement of material performance in extreme (high temperature, impact/abrasion, erosion, etc.) conditions.In the present study, the coatings were produced from a mixture of ferrous niobium, ferrous boron and iron powders in the ranges of -45µm particle size with different ratio. Fe12Nb5B3 and Fe2NbBalloys were coated on the AISI 1020 steel surface by TIG welding. The phases formed in the coated layer are Fe2B, NbB2, NbFeB and Fe0,2 Nb0,8 phases. The hardness of the presence phases are changing between 1689±85 HV0.01, and 181±7 HV0.1. Microstructural examinations were realized by optical and scanning electron microscopy. The wear and friction behaviors of Fe12Nb5B3 and Fe2NbB realized on the AISI 1020 steel were investigated by the technique of TIG welding by using ball-on-disk arrangement against alumina ball.

  10. Wear behavior of the surface alloyed AISI 1020 steel with Fe-Nb-B by TIG welding technique

    Energy Technology Data Exchange (ETDEWEB)

    Kilinc, B., E-mail: bkilinc@sakarya.edu.tr; Durmaz, M.; Abakay, E. [Department of Metallurgical and Materials Engineering, Institute of Arts and Sciences, SakaryaUniversity, Esentepe Campus, 54187Sakarya (Turkey); Sen, U.; Sen, S. [Department of Metallurgical and Materials Engineering, Engineering Faculty, Sakarya University, Esentepe Campus, 54187 Sakarya (Turkey)

    2015-03-30

    Weld overlay coatings also known as hardfacing is a method which involves melting of the alloys and solidification for applied coatings. Recently hardfacing by welding has become a commonly used technique for improvement of material performance in extreme (high temperature, impact/abrasion, erosion, etc.) conditions.In the present study, the coatings were produced from a mixture of ferrous niobium, ferrous boron and iron powders in the ranges of -45µm particle size with different ratio. Fe{sub 12}Nb{sub 5}B{sub 3} and Fe{sub 2}NbBalloys were coated on the AISI 1020 steel surface by TIG welding. The phases formed in the coated layer are Fe{sub 2}B, NbB{sub 2}, NbFeB and Fe0,2 Nb{sub 0,8} phases. The hardness of the presence phases are changing between 1689±85 HV{sub 0.01}, and 181±7 HV{sub 0.1}. Microstructural examinations were realized by optical and scanning electron microscopy. The wear and friction behaviors of Fe{sub 12}Nb{sub 5}B{sub 3} and Fe2NbB realized on the AISI 1020 steel were investigated by the technique of TIG welding by using ball-on-disk arrangement against alumina ball.

  11. Effect of welding processes on corrosion resistance of UNS S31803 duplex stainless steel

    International Nuclear Information System (INIS)

    An attractive combination of corrosion resistance and mechanical properties in the temperature range -50 to 250 .deg. C is offered by duplex stainless steel. However, undesirable secondary precipitation phase such as σ, γ2 and Cr2N may taken place at the cooling stage from the welding processes. Therefore, this paper describes the influence of different welding procedures such as manual metal arc welding (MMA), tungsten inert gas welding (TIG) and vacuum brazing on corrosion resistance of the welded joint for UNS S31803 duplex stainless steel. Microstructure and chemical compositions of the welded joint were examined. The weight loss of specimens immersed in 6% FeCl3 solution at 47.5 .deg. C for 24-hours was determined and used to evaluate the pitting resistance of duplex stainless steel and their welds. The region of heat-affected zone of specimen obtained by the MMA is much wider than that resulted from TIG, therefore, the weight loss of welds by MMA was larger than that of weld by TIG. The weight loss of brazed specimens cooled from slow cooling rate was larger than those of specimens cooled from high cooling rate, because the precipitation of σ phase. Beside that, the weight loss of brazed specimen is greater than those of the welded specimens. The galvanic corrosion was observed in brazed duplex stainless steel joints in the chloride solution

  12. Laser welding and syncristallization techniques comparison: “Ex vivo” study

    Science.gov (United States)

    Meleti, Marco; Vescovi, Paolo; Merigo, Elisabetta; Rocca, Jean-Paul

    2013-01-01

    Background and aims: Stabilization of implant abutments through electric impulses at high voltage for a very short time (electrowelding) was developed in the Eighties. In 2009, the same procedure was performed through the use of laser (laser welding) The aim of this study is to compare electrowelding and laser welding for intra-oral implant abutments stabilization on “ex vivo models” (pig jaws). Materials and methods: Six bars were welded with two different devices (Nd:YAG laser and Electrowelder) to eighteen titanium implant abutment inserted in three pig jaws. During the welding process, thermal increase was recorded, through the use of k-thermocouples, in the bone close to the implants. The strength of the welded joints was evaluated by a traction test after the removal of the implants. For temperature measurements a descriptive analysis and for traction test “values unpaired t test with Welch's correction” were performed: the significance level was set at PLaser welding gives a lower thermal increase than Electrowelding at the bone close to implants (Mean: 1.97 and 5.27); the strength of laser welded joints was higher than that of Electrowelding even if nor statistically significant. (Mean: 184.75 and 168.29) Conclusion: Electrowelding seems to have no advantages, in term of thermal elevation and strength, while laser welding may be employed to connect titanium implants for immediate load without risks of thermal damage at surrounding tissues. PMID:24511205

  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. A feasibility study on dissimilar metals friction weld strength analysis by ultrasonic techniques

    International Nuclear Information System (INIS)

    Friction welds are formed by the mechanisms of diffusion as well as mechanical inter-locking. The severe plastic flow at the interface by the forge action of the process brings the subsurface so close together that detection of any unbonded area becomes very difficult. No reliable method is available so far to determine the weld quality nondestructively. This paper presents an attempt to determine weld strength quantitatively using the ultrasonic pulse-echo method. The new approach calculates the coefficient of reflection based on measured amplitudes of the echoes. This coefficient provides a single quantitative measurement which involves both acoustic energy reflected at the welded interface as well as transmitted across the interface. As a result, it was known that the quantitative relationship between the coefficient and the weld strength(torsional strength) could be drawn. (Author)

  15. Welding process optimization of nuclear fuel rod using TIG technique for fuel irradiation tests

    International Nuclear Information System (INIS)

    The irradiation test of fuel elements was planned for the evaluation of nuclear fuel performance. To establish fabrication process satisfying the requirements of irradiation test, orbital-TIG welding system for fuel elements was developed, and preliminary welding experiments for optimizing process conditions of fuel element was performed. Fuel elements with 9.5mm diameter and 0.6mm wall thickness of cladding tubes and end caps have been used and optimum conditions of endcap welding have been selected. In this study, the qualification test was performed by tensile tests, helium leak inspections, and metallography examinations to qualify the end cap welding procedure. The soundness of the welds quality of nuclear fuel elements has been confirmed by mechanical tests and microstructural examinations

  16. Re-weldability tests of irradiated 316L(N) stainless steel using laser welding technique

    International Nuclear Information System (INIS)

    SS316L(N)-IG is the candidate material for the in-vessel and ex-vessel components of fusion reactors such as ITER (International Thermonuclear Experimental Reactor). This paper describes a study on re-weldability of un-irradiated and/or irradiated SS316L(N)-IG and the effect of helium generation on the mechanical properties of the weld joint. The laser welding process is used for re-welding of the water cooling branch pipeline repairs. It is clarified that re-welding of SS316L(N)-IG irradiated up to about 0.2 dpa (3.3 appm He) can be carried out without a serious deterioration of tensile properties due to helium accumulation. Therefore, repair of the ITER blanket cooling pipes can be performed by the laser welding process

  17. Theory and modeling of active brazing.

    Energy Technology Data Exchange (ETDEWEB)

    van Swol, Frank B.; Miller, James Edward; Lechman, Jeremy B.; Givler, Richard C.

    2013-09-01

    Active brazes have been used for many years to produce bonds between metal and ceramic objects. By including a relatively small of a reactive additive to the braze one seeks to improve the wetting and spreading behavior of the braze. The additive modifies the substrate, either by a chemical surface reaction or possibly by alloying. By its nature, the joining process with active brazes is a complex nonequilibrium non-steady state process that couples chemical reaction, reactant and product diffusion to the rheology and wetting behavior of the braze. Most of the these subprocesses are taking place in the interfacial region, most are difficult to access by experiment. To improve the control over the brazing process, one requires a better understanding of the melting of the active braze, rate of the chemical reaction, reactant and product diffusion rates, nonequilibrium composition-dependent surface tension as well as the viscosity. This report identifies ways in which modeling and theory can assist in improving our understanding.

  18. Micro-nano filler metal foil on vacuum brazing of SiCp/Al composites

    Science.gov (United States)

    Wang, Peng; Gao, Zeng; Niu, Jitai

    2016-06-01

    Using micro-nano (Al-5.25Si-26.7Cu)- xTi (wt%, x = 1.0, 1.5, 2.0, 2.5 and 3.0) foils as filler metal, the research obtained high-performance joints of aluminum matrix composites with high SiC particle content (60 vol%, SiCp/Al-MMCs). The effect of brazing process and Ti content on joint properties was investigated, respectively. The experimental results indicate that void free dense interface between SiC particle and metallic brazed seam with C-Al-Si-Ti product was readily obtained, and the joint shear strength enhanced with increasing brazing temperature from 560 to 580 °C or prolonging soaking time from 10 to 90 min. Sound joints with maximum shear strength of 112.5 MPa was achieved at 580 °C for soaking time of 90 min with (Al-5.25Si-26.7Cu)-2Ti filler, where Ti(AlSi)3 intermetallic is in situ strengthening phase dispersed in the joint and fracture occured in the filler metal layer. In this research, the beneficial effect of Ti addition into filler metal on improving wettability between SiC particle and metallic brazed seam was demonstrated, and capable welding parameters were broadened for SiCp/Al-MMCs with high SiC particle content.

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

    International Nuclear Information System (INIS)

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

  20. Process parameters optimization for friction stir welding of RDE-40 aluminium alloy using Taguchi technique

    Institute of Scientific and Technical Information of China (English)

    A.K.LAKSHMINARAYANAN; V.BALASUBRAMANIAN

    2008-01-01

    Taguchi approach was applied to determine the most influential control factors which will yield better tensile strength of the joints of friction stir welded RDE-40 aluminium alloy. In order to evaluate the effect of process parameters such as tool rotational speed, traverse speed and axial force on tensile strength of friction stir welded RDE-40 aluminium alloy, Taguchi parametric design and optimization approach was used. Through the Taguchi parametric design approach, the optimum levels of process parameters were determined. The results indicate that the rotational speed, welding speed and axial force are the significant parameters in deciding the tensile strength of the joint. The predicted optimal value of tensile strength of friction stir welded RDE-40 aluminium alloy is 303 MPa. The results were confirmed by further experiments.

  1. Application of Induction Heating for Brazing Parts of Solar Collectors

    Directory of Open Access Journals (Sweden)

    Kristína Demianová

    2012-01-01

    Full Text Available This paper reports on the application of induction heating for brazing parts of solar collectors made of Al alloys. The tube-flange joint is a part of the collecting pipe of a solar collector. The main task was to design an induction coil for this type of joint, and to select the optimum brazing parameters. Brazing was performed with AlSi12 brazing alloy, and corrosive and non-corrosive flux types were also applied. The optimum brazing parameters were determined on the basis of testing the fabricated brazed joints by visual inspection, by leakage tests, and by macro- and micro-analysis of the joint boundary. The following conditions can be considered to be the best for brazing Al materials: power 2.69 kW,brazing time 24 s, flux BrazeTec F32/80.

  2. Microstructure, mechanical properties and chemical degradation of brazed AISI 316 stainless steel/alumina systems

    Energy Technology Data Exchange (ETDEWEB)

    Paiva, O.C. [Instituto Superior de Engenharia do Porto (ISEP), Rua Dr. Antonio Bernardino de Almeida 431, 4200-072 Porto (Portugal)], E-mail: omp@isep.ipp.pt; Barbosa, M.A. [Instituto de Engenharia Biomedica (INEB), Rua do Campo Alegre, 823, 4150-180 Porto (Portugal); Faculdade de Engenharia da Universidade do Porto (FEUP), Rua Roberto Frias s/n, 4200-465 Porto (Portugal)

    2008-05-15

    The main aims of the present study are simultaneously to relate the brazing parameters with: (i) the correspondent interfacial microstructure, (ii) the resultant mechanical properties and (iii) the electrochemical degradation behaviour of AISI 316 stainless steel/alumina brazed joints. Filler metals on such as Ag-26.5Cu-3Ti and Ag-34.5Cu-1.5Ti were used to produce the joints. Three different brazing temperatures (850, 900 and 950 deg. C), keeping a constant holding time of 20 min, were tested. The objective was to understand the influence of the brazing temperature on the final microstructure and properties of the joints. The mechanical properties of the metal/ceramic (M/C) joints were assessed from bond strength tests carried out using a shear solicitation loading scheme. The fracture surfaces were studied both morphologically and structurally using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction analysis (XRD). The degradation behaviour of the M/C joints was assessed by means of electrochemical techniques. It was found that using a Ag-26.5Cu-3Ti brazing alloy and a brazing temperature of 850 deg. C, produces the best results in terms of bond strength, 234 {+-} 18 MPa. The mechanical properties obtained could be explained on the basis of the different compounds identified on the fracture surfaces by XRD. On the other hand, the use of the Ag-34.5Cu-1.5Ti brazing alloy and a brazing temperature of 850 deg. C produces the best results in terms of corrosion rates (lower corrosion current density), 0.76 {+-} 0.21 {mu}A cm{sup -2}. Nevertheless, the joints produced at 850 deg. C using a Ag-26.5Cu-3Ti brazing alloy present the best compromise between mechanical properties and degradation behaviour, 234 {+-} 18 MPa and 1.26 {+-} 0.58 {mu}A cm{sup -2}, respectively. The role of Ti diffusion is fundamental in terms of the final value achieved for the M/C bond strength. On the contrary, the Ag and Cu distribution along the

  3. Detached Melt Nucleation during Diffusion Brazing of a Technical Ni-based Superalloy: A Phase-Field Study

    Science.gov (United States)

    Böttger, B.; Apel, M.; Laux, B.; Piegert, S.

    2015-06-01

    Advanced solidification processes like welding, soldering, and brazing are often characterized by their specific solidification conditions. But they also may include different types of melting processes which themselves are strongly influenced by the initial microstructures and compositions of the applied materials and therefore are decisive for the final quality and mechanical properties of the joint. Such melting processes are often not well- understood because - compared to other fields of solidification science - relatively little research has been done on melting by now. Also, regarding microstructure simulation, melting has been strongly neglected in the past, although this process is substantially different from solidification due to the reversed diffusivities of the involved phases. In this paper we present phase-field simulations showing melting, solidification and precipitation of intermetallic phases during diffusion brazing of directionally solidified and heat-treated high-alloyed Ni- based gas turbine blade material using different boron containing braze alloys. Contrary to the common belief, melting of the base material is not always planar and can be further accompanied by detached nucleation and growth of a second liquid phase inside the base material leading to polycrystalline morphologies of the joint after solidification. These findings are consistent with results from brazed laboratory samples, which were characterized by EDX and optical microscopy, and can be explained in terms of specific alloy thermodynamics and inter-diffusion kinetics. Consequences of the gained new understanding for brazing of high- alloyed materials are discussed.

  4. Development of rapidly quenched nickel-based non-boron filler metals for brazing corrosion resistant steels

    Science.gov (United States)

    Ivannikov, A.; Kalin, B.; Suchkov, A.; Penyaz, M.; Yurlova, M.

    2016-04-01

    Corrosion-resistant steels are stably applied in modern rocket and nuclear technology. Creating of permanent joints of these steels is a difficult task that can be solved by means of welding or brazing. Recently, the use rapidly quenched boron-containing filler metals is perspective. However, the use of such alloys leads to the formation of brittle borides in brazing zone, which degrades the corrosion resistance and mechanical properties of the compounds. Therefore, the development of non-boron alloys for brazing stainless steels is important task. The study of binary systems Ni-Be and Ni-Si revealed the perspective of replacing boron in Ni-based filler metals by beryllium, so there was the objective of studying of phase equilibrium in the system Ni-Be-Si. The alloys of the Ni-Si-Be with different contents of Si and Be are considered in this paper. The presence of two low-melting components is revealed during of their studying by methods of metallography analysis and DTA. Microhardness is measured and X-ray diffraction analysis is conducted for a number of alloys of Ni-Si-Be. The compositions are developed on the basis of these data. Rapidly quenched brazing alloys can be prepared from these compositions, and they are suitable for high temperature brazing of steels.

  5. Position welding using disk laser-GMA hybrid welding

    Directory of Open Access Journals (Sweden)

    C.-H. Kim

    2008-05-01

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

  6. Mechanical and microstructural behavior of brazed aluminum / stainless steel mixed joints

    Science.gov (United States)

    Fedorov, V.; Weis, S.; Wagner, G.

    2016-03-01

    There is a requirement to combine different materials such as aluminum and stainless steel in industrial applications like automotive heat exchangers. Brazing offers the possibility to reduce the joining temperature in comparison to welding due to the lower liquidus temperature of the fillers. In the present work, the mechanical and microstructural behavior of aluminum / stainless steel mixed joints is investigated. The specimens are produced by induction brazing using an AlSi10filler and a non-corrosive flux. To evaluate the mechanical properties of the joints, tensile tests at elevated temperatures are carried out. Additionally, long-term thermal exposure experiments are done in order to investigate the changes in the microstructure.

  7. Fusion welding of Fe-added lap joints between AZ31B magnesium alloy and 6061 aluminum alloy by hybrid laser-tungsten inert gas welding technique

    International Nuclear Information System (INIS)

    Highlights: → Hybrid Laser-TIG fusion welding technique was used for joining Mg to Al alloys. → Laser defocusing amount determined penetration depth inside Al alloy of joints. → The addition of Fe interlayer suppressed Mg-Al intermetallics greatly in joints. → A maximum joint strength with optimum thickness of Fe interlayer was obtained. → Excessive addition of Fe interlayer was adverse for the strength improvement. -- Abstract: AZ31B magnesium alloy and 6061-T6 aluminum alloy were lap joined together with the addition of Fe interlayer by fusion welding of hybrid laser-tungsten inert gas (TIG) technique. The influence of location of laser focal spot (LFS) on joint penetration depth and that of the depth on joint strength were investigated. The results showed that when the LFS was just on the surface of Al plate, the deepest penetration could be obtained, which contributed to the improvement of shear strength of Fe-added joints, but not to the elevation of the strength of Mg/Al direct joints. The addition of Fe interlayer suppressed massive production of Mg-Al intermetallics but produced Fe-Al intermetallics in the fusion zone of the joints, whose micro-hardness was extremely high and was also adverse for the enhancement of joint shear strength. The effect of Fe-interlayer thickness on the joint shear strength was also examined, and the maximum shear strength of Fe-added joint could achieve 100 MPa with 0.13 mm thick Fe interlayer. The fracture modes of 0.07 and 0.13 mm Fe-interlayer-added joints were both quasi-cleavage, while those of direct and 0.22 mm interlayer-added joints were completely cleavage. The theoretical shear strength of the Fe-added joints was also discussed.

  8. Inspection of thin-walled pipe welds using mechanized ultrasonic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Lozev, M.; Spencer, R. [Edison Welding Inst., Columbus, OH (United States); Hodgkinson, D. [TransCanada PipeLines Ltd., Calgary, AB (Canada)

    2004-07-01

    This paper investigated applications of high-frequency single/multiprobe techniques and phased-array (PA) technology for the inspection of thin-walled pipes welds. Ultrasonic testing (UT), modeling and simulation was used as an effective way of determining that the desired calibration reflectors and flaws in thin-walled pipes can be accurately sized. A laboratory experiment was conducted in which simple or complex flaws were virtually split on several segments. Beam profile monitoring and automated ultrasonic testing was performed for non-focused 5, 10 and 15 MHz single elements, a variety of focused MHz elements, and a 10 MHz 32 element linear PA probe. A Mephisto model was used to examine the various echo-formation mechanisms. Beam interactions and connected planar flaws were examined. Two calibration targets were used: (1) a 1.5 mm diameter side-drilled hole; and (2) a 4 per cent deep notch. A thin-walled pipe sample was designed for the validation of modeling results. A commercially available PA system and computer software program was used to create focal laws, as well as to steer the beam, collect data, and perform the analysis. Results of the notch tilt models showed that inspection angles of approximately 58 to 68 degrees were the least sensitive to tilt. Signal amplitude losses of less than 10 decibels were observed when compared with the reference notch. The PA model for complex flaws showed that signal loss arising from tilt and skew stabilized at approximately 10 degrees due to a loss of amplitude. Larger sound beams resulted in a greater echo-dynamic that increased masking effects. It was concluded that the most accurate UT simulations were achieved using a 10 MHz, 32-element linear PA technology. 4 refs., 2 tabs., 8 figs.

  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. Improved diffusion welding and roll welding of titanium alloys

    Science.gov (United States)

    Holko, K. H.

    1973-01-01

    Auto-vacuum cleaning technique was applied to titanium parts prior to welding. This provides oxide-free welding surfaces. Diffusion welding can be accomplished in as little as five minutes of hot pressing. Roll welding can be accomplished with only ten percent deformation.

  11. Brazing of Stainless Steels to Yttria Stabilized Zirconia (YSZ) Using Silver -Base Brazes

    Science.gov (United States)

    Singh, Mrityunjay; Shpargel, Tarah P.; Asthana, Rajiv

    2005-01-01

    Three silver-base brazes containing either noble metal palladium (Palcusil-10 and Palcusil-15) or active metal titanium (Ticusil) were evaluated for high-temperature oxidation resistance, and their effectiveness in joining yttria stabilized zirconia (YSZ) to a corrosion-resistant ferritic stainless steel. Thermogravimetric analysis (TGA), and optical- and scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS) were used to evaluate the braze oxidation behavior and the structure and chemistry of the YSZ/braze/steel joints. The effect of the braze type and processing conditions on the interfacial microstructure and composition of the joint regions is discussed with reference to the chemical changes that occur at the interface. It was found that chemical interdiffusion of the constituents of YSZ, steel and the brazes led to compositional changes and/or interface reconstruction, and metallurgically sound joints.

  12. SiCp/2024Al铝基复合材料表面颗粒暴露及真空钎焊分析%Analysis on SiCp/2024 aluminum matrix composites surface reinforcements exposing and vacuum brazing

    Institute of Scientific and Technical Information of China (English)

    冯涛; 王引真; 楼松年; 张蒙蒙; 李春鹏

    2011-01-01

    Using the particle exposing and surface alloying technique of aluminum matrix composite, taking M6 and BAI88Si as the filler metal, the SiCp/2024Al aluminum matrix composite was brazed. The metallographic analysis, tensile test and Xray diffraction experiment were done. The test results indicate that the surface reinforcements are partly exposed by ( NaOH+HNO3 ) solution. The brazing joint combination state could be improved by depositing Cu element with M6 filler metal. The brazing joint and the base metal combined well with no obvious boundary. The reinforced composite solder joints with SiC particle are formed. There is no SiC particle agglomerated in the brazing joint. The tensile strength of the welded joint can reach 202 MPa. There is no Al4C3 brittleness phase formed in the brazing joint.%采用复合材料表面颗粒暴露及表面合金化工艺,利用M6和BAI88Si钎料对SiCp/2024Al铝基复合材料进行钎焊试验,并进行金相分析、拉伸试验和X射线衍射试验.结果表明:采用(NaOH+HNO3)工艺能将复合材料表面颗粒部分暴露出来;采用表面沉积Cu,使用M6钎料,能改善钎缝的结合状态;钎缝与铝基复合材料间无明显界限,结合良好,并形成了有SiC颗粒增强的复合钎缝,SiC颗粒在钎缝中无团聚现象;钎焊接头强度能达到202 MPa;在钎缝中无Al4C3脆性相生成.

  13. Robust Optimization of Thermal Aspects of Friction Stir Welding Using Manifold Mapping Techniques

    DEFF Research Database (Denmark)

    Larsen, Anders Astrup; Lahaye, Domenico; Schmidt, Henrik Nikolaj Blicher;

    2008-01-01

    The aim of this paper is to optimize a friction stir welding process taking robustness into account. The optimization problems are formulated with the goal of obtaining desired mean responses while reducing the variance of the response. We restrict ourselves to a thermal model of the process...

  14. Design and construction of a 33 GHz brazed accelerator waveguide for high gradient operation

    International Nuclear Information System (INIS)

    This paper discusses design and construction features of a precision machined and brazed traveling wave structure for use as a high gradient 33.3 GHz electron linear accelerator test section in a Two Beam Accelerator. Design emphasis was directed at meeting an RF filling time requirement of 12F<16ns, and at fabricating a test structure that would provide guidelines for demonstrating average accelerating fields of approximately 300 MV/m (maximum surface fields of 650 MV/m). Microwave measurement data, obtained during construction, are described and include a phase dispersion simple cold test technique for accurately predicting the structure filling time. A companion paper discusses plans for high power testing of both this brazed structure and a hybrid brazed/electroformed structure, using the Electron Laser Facility ELF at LLNL

  15. Nondestructive test of brazed cooling tubes of prototype bolometer camera housing using active infrared thermography.

    Science.gov (United States)

    Tahiliani, Kumudni; Pandya, Santosh P; Pandya, Shwetang; Jha, Ratneshwar; Govindarajan, J

    2011-01-01

    The active infrared thermography technique is used for assessing the brazing quality of an actively cooled bolometer camera housing developed for steady state superconducting tokamak. The housing is a circular pipe, which has circular tubes vacuum brazed on the periphery. A unique method was adopted to monitor the temperature distribution on the internal surface of the pipe. A stainless steel mirror was placed inside the pipe and the reflected IR radiations were viewed using an IR camera. The heat stimulus was given by passing hot water through the tubes and the temperature distribution was monitored during the transient phase. The thermographs showed a significant nonuniformity in the brazing with a contact area of around 51%. The thermography results were compared with the x-ray radiographs and a good match between the two was observed. Benefits of thermography over x-ray radiography testing are emphasized. PMID:21280850

  16. Tensometry technique for X-ray diffraction in applied analysis of welding; Tensometria por tecnica de difracao de raios X aplicada na analise de soldagens

    Energy Technology Data Exchange (ETDEWEB)

    Turibus, S.N.; Caldas, F.C.M.; Miranda, D.M.; Monine, V.I.; Assis, J.T., E-mail: snturibus@iprj.uerj.b [Universidade do Estado do Rio de Janeiro (IPRJ/UERJ), Nova Friburgo, RJ (Brazil). Inst. Politecnico

    2010-07-01

    This paper presents the analysis of residual stress introduced in welding process. As the stress in a material can induce damages, it is necessary to have a method to identify this residual stress state. For this it was used the non-destructive X-ray diffraction technique to analyze two plates from A36 steel jointed by metal inert gas (MIG) welding. The stress measurements were made by the sin{sup 2{psi}} method in weld region of steel plates including analysis of longitudinal and transverse residual stresses in fusion zone, heat affected zone (HAZ) and base metal. To determine the stress distribution along the depth of the welded material it was used removing of superficial layers made by electropolishing. (author)

  17. Microstructural Characteristics of a Stainless Steel/Copper Dissimilar Joint Made by Laser Welding

    Science.gov (United States)

    Chen, Shuhai; Huang, Jihua; Xia, Jun; Zhang, Hua; Zhao, Xingke

    2013-08-01

    The microstructures and its formation mechanism of a stainless steel/copper dissimilar joint by laser welding were investigated. It was found that the two modes of joining, i.e., welding-brazing and fusion welding, depend on different processing parameters. In the welding-brazing mode, the interface between copper and the fusion zone has scraggy morphology because the molten pool is frozen by solid copper with high thermal conductivity. The interdiffusion of elements occurs in the neighborhood of the interface, which leads to the metallurgy bond of the mode. In the fusion welding mode, the liquid phase in the fusion zone undergoes not only primary but also secondary liquid separation due to the high cooling rate and high supercooling level of laser welding. Some microcracks generated in the fusion zone by thermal stress mismatch are healed by liquid copper filling.

  18. 不锈钢真空钎焊管板连接微观特征及残余应力有限元分析%Microstructure Characteristics and Finite Element Analysis for Welding Residual Stress of Vacuum Brazed of Stainless Steel Tube Sheet Joint

    Institute of Scientific and Technical Information of China (English)

    吕彪; 熊缨

    2011-01-01

    采用拉伸试验机对304不锈钢管板结构真空钎焊强度进行了试验,运用金相和EDS方法分析了钎焊接头的微观组织特征.运用有限元ANSYS软件对微小尺寸不锈钢管板结构在真空钎焊过程中产生的残余应力进行了模拟.结果表明,应力集中出现在管板连接钎焊接头处,有限元分析获得了该处的残余应力分布规律.%The intensity of vacuum brazed of 304 stainless steel tube sheet structure has been tested with the tensile testing machine. This paper presented the microstructure characters of brazed joint with metallographic analysis and EDS analysis,studied the residual stress of vacuum brazed of the small size stainless steel tube sheet structure with finite element software ANSYS. The experimental results show that the stress concentration occurs at the joint of the brazed tube sheet, finite element analysis obtains the distribution of the residual stress. [ Ch,7 fig. 4 tab. 10 ref.

  19. Aluminum alloy weldability. Identification of weld solidification cracking mechanisms through novel experimental technique and model development

    Energy Technology Data Exchange (ETDEWEB)

    Coniglio, Nicolas

    2008-07-01

    The objective of the present thesis is to make advancements in understanding solidification crack formation in aluminum welds, by investigating in particular the aluminum 6060/4043 system. Alloy 6060 is typical of a family of Al-Mg-Si extrusion alloys, which are considered weldable only when using an appropriate filler alloy such as 4043 (Al-5Si). The effect of 4043 filler dilution (i.e. weld metal silicon content) on cracking sensitivity and solidification path of Alloy 6060 welds are investigated. Afterwards, cracking models are developed to propose mechanisms for solidification crack initiation and growth. Cracking Sensitivity. Building upon the concept that silicon improves weldability and that weldability can be defined by a critical strain rate, strain rate-composition combinations required for solidification crack formation in the Al- 6060/4043 system were determined using the newly developed Controlled Tensile Weldability (CTW) test utilizing local strain extensometer measurements. Results, presented in a critical strain rate - dilution map, show a crack - no crack boundary which reveals that higher local strain rates require higher 4043 filler dilution to avoid solidification cracking when arc welding Alloy 6060. Using the established crack - no crack boundary as a line of reference, additional parameters were examined and their influence on cracking characterized. These parameter influences have included studies of weld travel speed, weld pool contaminants (Fe, O, and H), and grain refiner additions (TiAl{sub 3} + Boron). Each parameter has been independently varied and its effect on cracking susceptibility quantified in terms of strain rate - composition combinations. Solidification Path. Solidification path of the Al-6060/4043 system was characterized using thermal analysis and phase identification. Increasing 4043 filler dilution from 0 to 16% in Alloy 6060 arc welds resulted in little effect on thermal arrests and microstructure, no effect on

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

    International Nuclear Information System (INIS)

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

  1. Inert Welding/Brazing Gas Filters and Dryers

    Science.gov (United States)

    Goudy, Jerry

    2009-01-01

    The use of hybridized carbon/silicon carbide (C/SiC) fabric to reinforce ceramic matrix composite face sheets and the integration of such face sheets with a foam core creates a sandwich structure capable of withstanding high-heat-flux environments (150 W/sq cm) in which the core provides a temperature drop of 1,000 C between the surface and the back face without cracking or delamination of the structure. The composite face sheet exhibits a bilinear response, which results from the SiC matrix not being cracked on fabrication. In addition, the structure exhibits damage tolerance under impact with projectiles, showing no penetration to the back face sheet. These attributes make the composite ideal for leading-edge structures and control surfaces in aerospace vehicles, as well as for acreage thermal protection systems and in high-temperature, lightweight stiffened structures. By tailoring the coefficient of thermal expansion (CTE) of a carbon fiber containing ceramic matrix composite (CMC) face sheet to match that of a ceramic foam core, the face sheet and the core can be integrally fabricated without any delamination. Carbon and SiC are woven together in the reinforcing fabric. Integral densification of the CMC and the foam core is accomplished with chemical vapor deposition, eliminating the need for bond-line adhesive. This means there is no need to separately fabricate the core and the face sheet, or to bond the two elements together, risking edge delamination during use. Fibers of two or more types are woven together on a loom. The carbon and ceramic fibers are pulled into the same "pick" location during the weaving process. Tow spacing may be varied to accommodate the increased volume of the combined fiber tows while maintaining a target fiber volume fraction in the composite. Foam pore size, strut thickness, and ratio of face sheet to core thickness can be used to tailor thermal and mechanical properties. The anticipated CTE for the hybridized composite is managed by the choice of constituents, varying fiber tow sizes and constituent part ratios. This structural concept provides high strength and stiffness at low density 1.06 g/cu cm in panels tested. Varieties of face sheet constructions are possible, including variations in fiber type and weave geometry. The integrated structures possible with this composite could eliminate the need for non-load-bearing thermal protection systems on top of a structural component. The back sheet can readily be integrated to substructures through the incorporation of ribs. This would eliminate weight and cost for aerospace missions.

  2. Recent Corrosion Research Trends in Weld Joints

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hwan Tae; Kil, Sang Cheol [Korea Institute of Science and Technology Information, Seoul (Korea, Republic of); Hwang, Woon Suk [Inha University, Incheon (Korea, Republic of)

    2007-04-15

    The increasing interest in the corrosion properties of weld joints in the corrosive environment is placing stringent demands on the manufacturing techniques and performance requirements, and the manufacture employs the high quality and efficiency welding process to produce welds. Welding plays an important role in the fabrication of chemical plants, nuclear power plant, ship construction, and this has led to an increasing attention to the corrosion resistant weld joints. This paper covers recent technical trends of welding technologies for corrosion resistance properties including the COMPENDEX DB analysis of welding materials, welding process, and welding fabrications

  3. Methods to Predict Stresses in Cutting Inserts Brazed Using Iron-Carbon Brazing Alloy

    Science.gov (United States)

    Konovodov, V. V.; Valentov, A. V.; Retuynskiy, O. Yu; Esekuev, Sh B.

    2016-04-01

    This work describes a method for predicting residual and operating stresses in a flat-form tool insert made of tungsten free carbides brazed using iron-carbon alloy. According to the studies’ results it is concluded that the recommendations relating to the limitation of a melting point of tool brazing alloys (950-1100°C according to different data) are connected with a negative impact on tools as a composite made of dissimilar materials rather than on hard alloys as a tool material. Due to the cooling process stresses inevitably occur in the brazed joint of dissimilar materials, and these stresses increase with the higher solidification temperature of the brazing alloy.

  4. X-Ray diffraction technique applied to study of residual stresses after welding of duplex stainless steel plates

    Energy Technology Data Exchange (ETDEWEB)

    Monin, Vladimir Ivanovitch; Assis, Joaquim Teixeira de [Instituto Politecnico do Rio e Janeiro (IPRJ), Nova Friburgo, RJ (Brazil); Lopes, Ricardo Tadeu; Turibus, Sergio Noleto; Payao Filho, Joao C., E-mail: sturibus@nuclear.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)

    2014-08-15

    Duplex stainless steel is an example of composite material with approximately equal amounts of austenite and ferrite phases. Difference of physical and mechanical properties of component is additional factor that contributes appearance of residual stresses after welding of duplex steel plates. Measurements of stress distributions in weld region were made by X-ray diffraction method both in ferrite and austenite phases. Duplex Steel plates were joined by GTAW (Gas Tungsten Arc Welding) technology. There were studied longitudinal and transverse stress components in welded butt joint, in heat affected zone (HAZ) and in points of base metal 10 mm from the weld. Residual stresses measured in duplex steel plates jointed by welding are caused by temperature gradients between weld zone and base metal and by difference of thermal expansion coefficients of ferrite and austenite phases. Proposed analytical model allows evaluating of residual stress distribution over the cross section in the weld region. (author)

  5. Active Metal Brazing and Characterization of Brazed Joints in Titanium to Carbon-Carbon Composites

    Science.gov (United States)

    Singh, M.; Shpargel, T. P.; Morscher, G. N.; Asthana, R.

    2006-01-01

    The Ti-metal/C-C composite joints were formed by reactive brazing with three commercial brazes, namely, Cu-ABA, TiCuNi, and TiCuSiI. The joint microstructures were examined using optical microscopy and scanning electron microscopy (SEM) coupled with energy dispersive spectrometry (EDS). The results of the microstructure analysis indicate solute redistribution across the joint and possible metallurgical bond formation via interdiffusion, which led to good wetting and spreading. A tube-on-plate tensile test was used to evaluate joint strength of Ti-tube/ C-C composite joints. The load-carrying ability was greatest for the Cu-ABA braze joint structures. This system appeared to have the best braze spreading which resulted in a larger braze/C-C composite bonded area compared to the other two braze materials. Also, joint loadcarrying ability was found to be higher for joint structures where the fiber tows in the outer ply of the C-C composite were aligned perpendicular to the tube axis when compared to the case where fiber tows were aligned parallel to the tube axis.

  6. Brazing of photocathode RF gun structures in Hydrogen atmosphere: Process qualification, effect of brazing on RF properties and vacuum compatibility

    International Nuclear Information System (INIS)

    In this paper, we report on the development of a brazing process for an ultra-high vacuum (UHV) compatible photocathode RF gun structure developed at our Centre. The choice of brazing alloy and its form, brazing clearance between parts to be joined and the brazing cycle adopted have been qualified through metallographic examination of identical joints on an OFE copper prototype that was cut open after brazing. The quality of brazed joint not only affects the UHV compatibility of the gun, but also influences the RF parameters finally achieved. A 2-D electromagnetic code, SUPERFISH, was used to predict the variation in RF parameters before and after brazing considering actual brazing clearances provided between the parts to be joined. Results obtained from low power RF measurements on the brazed gun structure confirm the integrity of the brazed joints and show good agreement with those predicted by electromagnetic simulations. The brazed gun structure has been leak-tested and pumped down to a vacuum level limited by the vacuum compatibility of the flange-fittings employed in the setup.

  7. Braze Development of Graphite Fiber for Use in Phase Change Material Heat Sinks

    Science.gov (United States)

    Quinn, Gregory; Beringer, Woody; Gleason, Brian; Stephan, Ryan

    2011-01-01

    Hamilton Sundstrand (HS), together with NASA Johnson Space Center, developed methods to metallurgically join graphite fiber to aluminum. The goal of the effort was to demonstrate improved thermal conductance, tensile strength and manufacturability compared to existing epoxy bonded techniques. These improvements have the potential to increase the performance and robustness of phase change material heat sinks that use graphite fibers as an interstitial material. Initial work focused on evaluating joining techniques from four suppliers, each consisting of a metallization step followed by brazing or soldering of one inch square blocks of Fibercore graphite fiber material to aluminum end sheets. Results matched the strength and thermal conductance of the epoxy bonded control samples, so two suppliers were down-selected for a second round of braze development. The second round of braze samples had up to a 300% increase in strength and up to a 132% increase in thermal conductance over the bonded samples. However, scalability and repeatability proved to be significant hurdles with the metallization approach. An alternative approach was pursued which used a nickel braze allow to prepare the carbon fibers for joining with aluminum. Initial results on sample blocks indicate that this approach should be repeatable and scalable with good strength and thermal conductance when compared with epoxy bonding.

  8. Study of technique and performance of laser beam welding for W18Cr4V and 65Mn

    Institute of Scientific and Technical Information of China (English)

    Jianhua Yao(姚建华); Zhimin Fang(方志民); Wei Zhang(张伟)

    2004-01-01

    In this experiment, we used 7-kW continuous wave (CW) CO2 low order mode laser and YAG impulse laser to deeply weld high-speed steel (W18Cr4V) and spring steel (65Mn). To welded joint, we analyzed its nicrostructure, micro hardness and fracture appearance for different welding technology by metallography microscope, scanning electron microscopy and bending strength test, discussed its action of fracture and the relation between its structural transformation and strength. At last, we offered an optimum welding technology having no welding defect by the comparison and analysis of processing property.

  9. Studies of residual stress measurement and analysis techniques for a PWR dissimilar weld joint

    International Nuclear Information System (INIS)

    For evaluation of the PWSCC crack propagation behavior, a test model was produced using the same fabrication process of Japanese PWR plants and the stress distribution change was measured during a fabrication process such as a hydrostatic test, welding a main coolant pipe to the stainless steel safe end and an operation condition test. For confirmation of validity of the numerical estimation method of the stress distribution, FE analysis was performed to calculate the stress distributions for each fabrication process. From the validation procedure, a standard residual stress evaluation method was established. Furthermore for consideration of characteristics of PWSCC’s propagation behavior of the dissimilar welding joint of the safe end nozzles, the influence coefficients at the deepest point for the stress intensity factors of axial cracks with large aspect ratio a/c (crack depth/half of surface crack length) was prepared. The crack shape was assumed a rectangular shape and the stress intensity factors at the deepest point of the crack were calculated with change of crack depth using FE analysis. By using these stress distribution and influence coefficients, a behavior of a PWSCC crack propagation at the safe end nozzles can be estimated easily and rationally.

  10. Studies of residual stress measurement and analysis techniques for a PWR dissimilar weld joint

    Energy Technology Data Exchange (ETDEWEB)

    Ogawa, Naoki, E-mail: naoki2_ogawa@mhi.co.jp [Mitsubishi Heavy Industries, Ltd., 2-1-1, Shinhama, Arai-cho, Takasago 676-8686 (Japan); Muroya, Itaru; Iwamoto, Youichi; Ohta, Takahiro; Ochi, Mayumi; Hojo, Kiminobu [Mitsubishi Heavy Industries, Ltd., 2-1-1, Shinhama, Arai-cho, Takasago 676-8686 (Japan); Ogawa, Kazuo [Japan Nuclear Energy Safety Organization, 3-17-1, Toranomon, Minato-ku, Tokyo 105-0001 (Japan)

    2012-02-15

    For evaluation of the PWSCC crack propagation behavior, a test model was produced using the same fabrication process of Japanese PWR plants and the stress distribution change was measured during a fabrication process such as a hydrostatic test, welding a main coolant pipe to the stainless steel safe end and an operation condition test. For confirmation of validity of the numerical estimation method of the stress distribution, FE analysis was performed to calculate the stress distributions for each fabrication process. From the validation procedure, a standard residual stress evaluation method was established. Furthermore for consideration of characteristics of PWSCC's propagation behavior of the dissimilar welding joint of the safe end nozzles, the influence coefficients at the deepest point for the stress intensity factors of axial cracks with large aspect ratio a/c (crack depth/half of surface crack length) was prepared. The crack shape was assumed a rectangular shape and the stress intensity factors at the deepest point of the crack were calculated with change of crack depth using FE analysis. By using these stress distribution and influence coefficients, a behavior of a PWSCC crack propagation at the safe end nozzles can be estimated easily and rationally.

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

    Institute of Scientific and Technical Information of China (English)

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

    2004-01-01

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

  12. Design and realization of a welding oscillator

    OpenAIRE

    Özcan, Muciz

    2014-01-01

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

  13. Experimental study of cyclic creep and high-cycle fatigue of welded joints of St3 steel by the DIC technique

    Energy Technology Data Exchange (ETDEWEB)

    Kibitkin, Vladimir V., E-mail: vvk@ispms.tsc.ru; Solodushkin, Andrey I., E-mail: s.ai@sibmail.com; Pleshanov, Vasily S., E-mail: vsp@ispms.tsc.ru [Institute of Strength Physics and Materials Science SB RAS, Tomsk, 634055 (Russian Federation)

    2015-10-27

    In the paper the mechanisms of plastic deformation and fracture of welded joints of steel St3 were investigated at high-cycle fatigue and cyclic creep by the digital image correlation (DIC) technique. The evolution of strain rate is studied for the following regions: base metal, HAZ, and fusion zone. This strain rate evolution can be considered as a mechanical response of material. Three stages of deformation evolution are shown: deformation hardening (I), fatigue crack initiation (II), and the last stage is related to main crack (III). Two criteria are offered to evaluate the current mechanical state of welded joints.

  14. A study on pseudo interface wave technique for CRDM weld defects in nuclear power plants

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jaesun, E-mail: jaesun@pusan.ac.kr, E-mail: jpp@pusan.ac.kr; Park, Junpil, E-mail: jaesun@pusan.ac.kr, E-mail: jpp@pusan.ac.kr [Graduate school, School of Mechanical Engineering, Pusan National University, Pusan (Korea, Republic of); Cho, Younho, E-mail: mechcyh@pusan.ac.kr [School of Mechanical Engineering, Pusan National University, Pusan (Korea, Republic of); Huh, Hyung, E-mail: kbpark2@kaeri.re.kr, E-mail: dokim@kaeri.re.kr; Park, Keun-Bae, E-mail: kbpark2@kaeri.re.kr, E-mail: dokim@kaeri.re.kr; Kim, Dong-Ok, E-mail: kbpark2@kaeri.re.kr, E-mail: dokim@kaeri.re.kr [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-03-31

    The nuclear power plant inspection is very important for the safety issue. However due to some radiation and geometric problems, the detection of CRDM(Control Rod Drive Mechanism) can be very difficult by using conventional Ultrasonic Testing method. Also the shrink fit boundary condition can also be an obstacle for the inspection in this paper, instead of conventional Ultrasonic Testing, guided wave was used for the detection of some complicated structures. The CRDM nozzle was installed in reactor head with perfect shrink fit condition by using stainless steel. The wave amplitude distribution on the circumferential direction was calculated with various boundary conditions and the experimental result shows a possibility of the defect detection on J-groove weld.

  15. A study on pseudo interface wave technique for CRDM weld defects in nuclear power plants

    Science.gov (United States)

    Lee, Jaesun; Park, Junpil; Cho, Younho; Huh, Hyung; Park, Keun-Bae; Kim, Dong-Ok

    2015-03-01

    The nuclear power plant inspection is very important for the safety issue. However due to some radiation and geometric problems, the detection of CRDM(Control Rod Drive Mechanism) can be very difficult by using conventional Ultrasonic Testing method. Also the shrink fit boundary condition can also be an obstacle for the inspection in this paper, instead of conventional Ultrasonic Testing, guided wave was used for the detection of some complicated structures. The CRDM nozzle was installed in reactor head with perfect shrink fit condition by using stainless steel. The wave amplitude distribution on the circumferential direction was calculated with various boundary conditions and the experimental result shows a possibility of the defect detection on J-groove weld.

  16. Interface Behavior of Mg alloy Eutectic Brazing%镁合金共晶钎焊界面行为

    Institute of Scientific and Technical Information of China (English)

    白莉

    2012-01-01

    Magnesium alloy was bonded by eutectic contacting reaction brazing using pure silver interlayer, and the microstructure, interface diffusion behavior of elements of the welded joint was studied. The results from the experiment show that the eutectic contacting reaction brazing can achieve effective connection of magnesium alloy, and the interface has relatively higher content of silver, which has the obvious trend of diffusion for both sides of magnesium alloy.%采用纯银做中间层共晶钎焊工艺对镁合金进行连接,研究了接头微观组织及界面元素扩散行为.结果表明,采用共晶钎焊可以实现镁合金的有效连接,结合界面银元素相对含量较高,有着明显的向两边镁合金扩散的趋势.

  17. Laser Brazing of Aluminum with a New Filler Wire AlZn13Si10Cu4

    Science.gov (United States)

    Tang, Z.; Seefeld, T.; Vollertsen, F.

    Laser brazing processes of aluminum with both single beam and double beam techniques were developed using a new AlZn13Si10Cu4 filler wire which has a lower solidification range comparing to normal AlSi12 filler wire and the base material. Brazing experiments on both bead on plate and flange joints showed that the new wire has a very good wettability on the aluminum samples. Comparing to the AlSi12 wire one needs a lower heat input (in some cases 73% less heat input) for joining the same samples with the new filler wire and reaches a high hardness value in the joint. In addition, brazing with double beam technique showed its potential to increase the joint quality.

  18. Short cycle brazing of an alumina dispersion strengthened copper alloy

    International Nuclear Information System (INIS)

    An alumina dispersion strengthened copper alloy (with 0.07 wt, % alumina) has been proposed for several specialized applications in fusion reactors, such as the stabilizer in superconducting magnets and the structural material for divertors and limiters. In this research, brazed joints of the alumina dispersion strengthened copper alloy were developed using resistance heating brazing. The BCuP-3 brazing alloy was chosen based upon its low activation characteristics. Brazing was conducted using a GLEEBLE 1500 system with which time, temperature, and stress were precisely controlled. Butt-brazed joints with different brazing times were evaluated based on tensile and bending fatigue properties. Results from these tests reveal that the optimum braze time is approximately 1 minute at 8000C with a holding stress of 0.5 MPa. Metallography examinations were conducted on both the as brazed structure and the fracture surfaces. In the former, a transition layer (about 10 μm tick) was formed between the braze metal and the base alloy. Microhardness measurements across the braze did not show any hardening or softening effect due to the brazing process. Metallography of the fractured tensile and fatigue samples showed that cracks always penetrated through the interface between the transition layer and the braze metal. Semiquantitative energy dispersive x-ray spectroscopy (EDS) analysis was also performed across the joint. Profiles of P and Ag showed that P diffused very quickly into base metal along grain boundaries. A strong Al peak (associated with the detection of Al2O3) was found that corresponded with the transition layer. The presence of the alumina particles in the transition zone restricts the grain growth process in this region, resulting in relatively fine grain size

  19. 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.

  20. Challenges to Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

    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......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...

  1. Ultrasonic imaging methods for quality evaluation of the CANDU fuel bundle welds

    International Nuclear Information System (INIS)

    For more than 20 years, the quality control of the end-cap/end-plates welds and of the brazed appendage joints is made by destructive methods (metallographic examinations or mechanical tests) on specimens sampled from production. Having a very limited statistics, these destructive methods are useful only to indicate 'trends' of the production quality, not for detecting infrequent single defect events. It is recognized that nondestructive examination techniques are required to achieve sufficient 'visibility' of the production quality, at a statistically significant sampling rate. For this reason, the INR-Ultra-acoustics R and D has developed the MICROSCAN equipment family for high resolution ultrasonic imaging, with performances close to the Acoustic Microscopy domain. The paper makes a presentation of the performances of the MICROSCAN 02/03 equipment for B and C-scan high-frequency ultrasonic imaging. Experimental results are presented and comparisons are make with metallographic examinations. (Author) 8 Figs., 4 Refs

  2. Developments in tube to tubeplate welding

    International Nuclear Information System (INIS)

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

  3. 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.

  4. Study on alumina-alumina brazing for application in vacuum chambers of proton synchrotron

    International Nuclear Information System (INIS)

    The paper describes an experimental study to standardize vacuum brazing process to obtain satisfactory high purity alumina brazed joints for application in rapid cycle proton synchrotron machine. Two different brazing routes, adopted for making alumina-alumina brazed joints, included (i) multi-step Mo-Mn metallization and brazing with BVAg-8 alloy and (ii) advanced single-step active brazing with CuSil-ABA alloy. Brazed alumina specimens, prepared by both the routes, yielded ultra high vacuum compatible, helium leak tight and bakeable joints. Active-brazed specimens exhibited satisfactory strength values in tensile and four-point bend tests. Metallized-brazed specimens, although exhibited relatively lower tensile strength than the targeted value, displayed satisfactory flexural strength in four-point bend test. The results of the study demonstrated that active brazing is the simple and cost effective alternative to conventional metallization route for producing satisfactory brazed joints for application in rapid cycle proton synchrotron machine. (author)

  5. Application of laser in seam welding of dissimilar steel to aluminium joints for thick structural components

    Science.gov (United States)

    Meco, S.; Pardal, G.; Ganguly, S.; Williams, S.; McPherson, N.

    2015-04-01

    Laser welding-brazing technique, using a continuous wave (CW) fibre laser with 8000 W of maximum power, was applied in conduction mode to join 2 mm thick steel (XF350) to 6 mm thick aluminium (AA5083-H22), in a lap joint configuration with steel on the top. The steel surface was irradiated by the laser and the heat was conducted through the steel plate to the steel-aluminium interface, where the aluminium melts and wets the steel surface. The welded samples were defect free and the weld micrographs revealed presence of a brittle intermetallic compounds (IMC) layer resulting from reaction of Fe and Al atoms. Energy Dispersive Spectroscopy (EDS) analysis indicated the stoichiometry of the IMC as Fe2Al5 and FeAl3, the former with maximum microhardness measured of 1145 HV 0.025/10. The IMC layer thickness varied between 4 to 21 μm depending upon the laser processing parameters. The IMC layer showed an exponential growth pattern with the applied specific point energy (Esp) at a constant power density (PD). Higher PD values accelerate the IMC layer growth. The mechanical shear strength showed a narrow band of variation in all the samples (with the maximum value registered at 31.3 kN), with a marginal increase in the applied Esp. This could be explained by the fact that increasing the Esp results into an increase in the wetting and thereby the bonded area in the steel-aluminium interface.

  6. Microstructural Development and Mechanical Properties for Reactive Air Brazing of ZTA to Ni Alloys using Ag-CuO Braze Alloys

    Energy Technology Data Exchange (ETDEWEB)

    Prevost, Erica; DeMarco, A.Joseph; MacMichael, Beth; Joshi, Vineet V.; Meier, Alan; Hoffman, John W.; Walker, William J.

    2014-12-01

    Reactive air brazing (RAB) is a potential joining technique to join metal alloys to ceramics for a variety of applications. In the current study, nickel (Ni) alloys were heat treated to form an oxide layer prior to RAB joining to zirconia toughened alumina (ZTA). The Ni alloys evaluated were Nicrofer 6025 HT, Inconel 600, Inconel 693, Haynes 214 and Inconel 601. The ZTA studied had compositions of 0 to 15 wt% zirconia and 0 to 14 wt% glass. Four point-bend tests were performed to evaluate the joint strength of ZTA/ZTA and ZTA/nickel alloys brazed with Ag-2wt% CuO braze alloys. It was determined that the joint strength is not a function of the ZTA composition, but that the strength is a strong function of the chemistry and microstructure of the oxide layer formed on the nickel alloy. It was determined that an increase in the aluminum content of the Ni alloy resulted in an increase of the thickness of alumina in the oxide layer and was directly proportional to the bond strength with the exception of Inconel 601 which exhibited relatively high joint strengths even though it had a relatively low aluminum content.

  7. Failure Assessment Diagram for Brazed 304 Stainless Steel Joints

    Science.gov (United States)

    Flom, Yory

    2011-01-01

    Interaction equations were proposed earlier to predict failure in Albemet 162 brazed joints. Present study demonstrates that the same interaction equations can be used for lower bound estimate of the failure criterion in 304 stainless steel joints brazed with silver-based filler metals as well as for construction of the Failure Assessment Diagrams (FAD).

  8. Reactive Boride Brazing on Low-Alloy Automotive Grade Steel

    Science.gov (United States)

    Palanisamy, B.; Upadhyaya, A.

    2011-11-01

    Brazing is a widely used process to improve the performance of steels used in automotive applications. The substrate material is often exposed to harsh conditions in these applications and may affect the service life of the component. Reactive boride brazing aims to improve the mechanical properties of the substrate material by forming a ceramic-metal composite coating in a single-step process in situ. In this study, sintered Ancor 4300 low-alloy steel is used as the substrate with chromium-rich braze and chromium-lean braze materials. The mechanical properties of the brazed samples were studied in detail using microindentation hardness measurements and the transverse rupture test. The results indicate that the brazed superlayer has a 10 times higher hardness. There was a significant improvement in the transverse rupture strength of the steel brazed with the chromium-rich boride as compared to the pure substrate material. In an effort to reduce processing time, green compacts of the substrate were also directly brazed and yielded favorable results.

  9. Brazing of stainless steel; Stainless ko no rozuke

    Energy Technology Data Exchange (ETDEWEB)

    Matsu, T.

    1996-04-01

    This paper explains brazing of stainless steel as to its processing materials, brazing materials, brazing methods, and brazing works. When performing brazing at higher than 800{degree}C on a martensite-based stainless steel represented by the 13Cr steel, attention is required on cracking caused by quenching. When a ferrite-based stainless steel represented by the 18Cr steel is heated above 900{degree}C, crystalline particles grow coarser, causing their tenacity and corrosion resistance to decline. High-temperature long-time heating in brazing in a furnace demands cautions. Austenite-based stainless steel represented by the 18Cr-8Ni steel has the best brazing performance. However, since the steel has large thermal expansion coefficient and low thermal conductivity, attention is required on strain and deformation due to heating, and on localized overheating. Deposition hardened stainless steel made of the Cr-Ni alloy steel added with aluminum and titanium has poor wettability in a brazing work, hence pretreatment is required for the purpose of activation. 9 figs., 7 tabs.

  10. Semi-nondestructive measurement of weld residual stress distribution in austenitic stainless steel using indentation technique without reference load under non-stress state

    International Nuclear Information System (INIS)

    In this study, semi-nondestructive measurement of non-equibiaxial stress using the indentation technique without a reference load under the non-stress state has been applied to low-carbon austenitic stainless steel welds. In order to clarify the material dependency of the applied procedure, two constants (the load ratio and the conversion factor) for stress determination were experimentally quantified and compared with those of high-strength structural steel. The accuracy of stress measurement by the procedure applied to low-carbon austenitic stainless steel welds was verified through a comparison with the X-ray diffraction and stress relief methods. Based on the results, the applied procedure had less dependency on the material properties of these steels and was in good agreement with the conventional techniques in the overall distribution of residual stress. (author)

  11. Microstructure and mechanical properties of MoSi2–MoSi2 joints brazed by Ag–Cu–Zr interlayer

    International Nuclear Information System (INIS)

    Highlights: ► Brazing of MoSi2–MoSi2 using Ag–Cu–Zr interlayer at different temperatures. ► Investigation of shear strength and microstructure of the joint by SEM and XRD. ► Formation of Ag-rich solid solution and various Cu–Zr–Si intermetallic compounds. ► Maximum shear strength for the sample with 830 °C brazing temperature. ► Various fracture path and morphology at different brazing temperatures. - Abstract: The present work investigates joining of two MoSi2 parts through Cusil/Zr/Cusil interlayer with Cusil being a commercial eutectic of Cu–Ag alloy. The joining operation was implemented in an inert gas tube furnace by brazing. The brazing temperature ranged from 800 to 930 °C while the operation lasted for 60 min. Evaluation of joints strength through shear loading identified the maximum strength 60.31 MPa for the brazed sample at 830 °C. Interfacial microstructure was studied by Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS) and X-ray Diffraction (XRD) techniques. Applying the temperature of 830 °C was led to a uniform dense joint consisting of various phases with excellent bonding within the interfaces. XRD and EDS results revealed different phases such as Mo5Si3, Ag-rich solid solution and Cu10Zr7 at the interface. At higher brazing temperatures the amount of intemetallic compounds and residual stresses increased and therefore, mechanical properties of the joint degraded. The fracture analysis by SEM revealed various fracture path and morphology for different brazing temperatures

  12. Fracture strength of different soldered and welded orthodontic joining configurations with and without filling material

    Directory of Open Access Journals (Sweden)

    Jens Johannes Bock

    2008-10-01

    Full Text Available The aim of this study was to compare the mechanical strength of different joints made by conventional brazing, TIG and laser welding with and without filling material. Five standardized joining configurations of orthodontic wire in spring hard quality were used: round, cross, 3 mm length, 9 mm length and 7 mm to orthodontic band. The joints were made by five different methods: brazing, tungsten inert gas (TIG and laser welding with and without filling material. For the original orthodontic wire and for each kind of joint configuration or connecting method 10 specimens were carefully produced, totalizing 240. The fracture strengths were measured with a universal testing machine (Zwick 005. Data were analyzed by ANOVA (p=0.05 and Bonferroni post hoc test (p=0.05. In all cases, brazing joints were ruptured on a low level of fracture strength (186-407 N. Significant differences between brazing and TIG or laser welding (p<0.05, Bonferroni post hoc test were found in each joint configuration. The highest fracture strength means were observed for laser welding with filling material and 3 mm joint length (998 N. Using filling materials, there was a clear tendency to higher mean values of fracture strength in TIG and laser welding. However, statistically significant differences were found only in the 9-mm long joints (p<0.05, Bonferroni post hoc test. In conclusion, the fracture strength of welded joints was positively influenced by the additional use of filling material. TIG welding was comparable to laser welding except for the impossibility of joining orthodontic wire with orthodontic band.

  13. Two-beam Laser Brazing of Thin Sheet Steel for Automotive Industry Using Cu-base Filler Material

    Science.gov (United States)

    Mittelstädt, C.; Seefeld, T.; Reitemeyer, D.; Vollertsen, F.

    This work shows the potential of two-beam laser brazing for joining both Zn-coated steel and 22MnB5. Brazing of Zn-coated steel sheets using Cu-Si filler wire is already state of the art in car manufacturing. New press-hardened steels like 22MnB5 are more and more used in automotive industry, offering high potential to save costs and improve structural properties (reduced weight / higher stiffness). However, for joining of these ultra-high strength steels investigations are mandatory. In this paper, a novel approach using a two-beam laser brazing process and Cu-base filler material is presented. The use of Cu-base filler material leads to a reduced heat input, compared to currently applied welding processes, which may result in benefits concerning distortion, post processing and tensile strength of the joint. Reliable processing at desired high speeds is attained by means of laser-preheating. High feed rates prevent significant diffusion of copper into the base material.

  14. First industrial application of the auto-adaptative MAG STT welding technique with laser joint tracking; Premiere application industrielle du soudage MAG STT avec suivi de joint auto-adaptatif au laser

    Energy Technology Data Exchange (ETDEWEB)

    Tran Tien, Th. [Institut de Soudure, 93 - Villepinte (France)

    2007-05-15

    The Welding Institute has participated to the plan of construction of the Large Hadron Collider. The hoops of the dipolar magnets are composed of two half cylinders 15 m in length in 10 mm 316LN austenitic stainless steel and are assembled around the magnet in a horizontal-vertical position. The Welding Institute has developed a software for carrying out the auto-adaptative welding technique with laser joint tracking, in using the MAG STT (Surface Tension Transfer) process. The modelling of the welding laws and the strategy of filling the joints in multi-paths absorb the physical tolerances of the preparation (clearance, poor alignment, root..) in dynamic welding condition too. (O.M.)

  15. 29 CFR 1910.253 - Oxygen-fuel gas welding and cutting.

    Science.gov (United States)

    2010-07-01

    ... accordance with the regulations of the U.S. Department of Transportation, 49 CFR parts 171-179. (ii... reach them, or fire-resistant shields shall be provided. (J) Cylinders shall not be placed where they...) Joints in brass or copper pipe shall be welded, brazed, threaded, or flanged. If of the socket type,...

  16. 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.…

  17. Welding IV.

    Science.gov (United States)

    Allegheny County Community Coll., Pittsburgh, PA.

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

  18. Effect of the surface preparation techniques on the EBSD analysis of a friction stir welded AA1100-B{sub 4}C metal matrix composite

    Energy Technology Data Exchange (ETDEWEB)

    Guo, J., E-mail: junfeng.guo@cnrc-nrc.gc.ca [University of Quebec at Chicoutimi, Chicoutimi (QC), G7H 2B1 (Canada); Aluminium Technology Centre, National Research Council Canada, Chicoutimi (QC), G7H 8C3 (Canada); Amira, S.; Gougeon, P. [Aluminium Technology Centre, National Research Council Canada, Chicoutimi (QC), G7H 8C3 (Canada); Chen, X.-G. [University of Quebec at Chicoutimi, Chicoutimi (QC), G7H 2B1 (Canada)

    2011-09-15

    Aluminum based metal matrix composites (MMCs) have been used in various automobile, aerospace and military industries. Yet characterization of the microstructure in these materials remains a challenge. In the present work, the grain structure in the matrix of B{sub 4}C particulate reinforced MMCs and their friction stir welds is characterized by using optical metallography and the electron backscatter diffraction (EBSD) technique. Optical metallography can partially reveal the grain structure in the matrix of AA1100-16 vol.% B{sub 4}C composite. The EBSD technique has been successfully applied to characterize the grain structure in the AA1100-16 vol.% B{sub 4}C friction stir welds, which provides a powerful tool to follow the microstructural evolution of MMC materials during friction stir welding (FSW). Both mechanical polishing and ion beam polishing are used for the EBSD sample preparation. The effect of the sample preparation on the EBSD data acquisition quality is studied. Some typical examples, such as the identification of grains and subgrains, grain size distribution, deformation fields and the texture components are given. - Highlights: {yields} EBSD has been used to characterize the grain structure of Al-B{sub 4}C MMCs. {yields} Mechanical and ion beam polishing are compared for EBSD sample preparation of MMCs. {yields} EBSD shows great advantages over optical microscopy for microtexture analysis of MMCs.

  19. Development of Remote Weld Testing Technique for Moisture Separator and Reheater Tubes in Nuclear Power Plants

    International Nuclear Information System (INIS)

    The heat exchanger tube in nuclear power plants is mainly fabricated from nonferromagnetic material such as a copper, titanium, and inconel alloy, but the moisture separator and reheater tube in the turbine system is fabricated from ferromagnetic material such as a carbon steel or ferrite stainless steel which has a good mechanical properties in harsh environments of high pressure and temperature. Especially, the moisture separator and reheater tubes, which use steam as a heat transfer media, typically employ a tubing with integral fins to furnish higher heat transfer rates. The ferromagnetic tube typically shows superior properties in high pressure and temperature environments than a nonferromagnetic material, but can make a trouble during the normal operation of power plants because the ferrous tube has service-induced damage forms including a steam cutting, erosion, mechanical wear, stress corrosion cracking, etc. Therefore, nondestructive examination is periodically performed to evaluate the tube integrity. Now, the remote field testing(RFT) technique is one of the solution for examination of ferromagnetic tube because the conventional eddy current technique typically can not be applied to ferromagnetic tube such as a ferrite stainless steel due to the high electrical permeability of ferrous tube. In this study, we have designed RFT probes, calibration standards, artificial flaw specimen, and probe pusher-puller necessary for field application, and have successfully carry out RFT examination of the moisture separator and reheater tube of nuclear power plants.

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

    International Nuclear Information System (INIS)

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

  1. 基于压电换能器的新型超声波助焊技术%Ultrasonic Welding-promoting Technique Based on Piezoelectric Transducer

    Institute of Scientific and Technical Information of China (English)

    刘婷; 高椿明

    2012-01-01

    Using the mechanical effect of the ultrasonic wave, the ultrasonic welding-promoting technique has been presented. The ultrasonic wave generating device generates a high-frequency oscillation signal; a high-frequency mechanical vibration, converted by the piezoelectric transducer, transmits to the medium; the ultrasonic wave radiates forward in the solder solution, resulting in a strong pressure and an instant oscillation in the solder solution, lowering the surface tension of the solder solution, ensuring the expansion, flow and infiltration of the solder solution on the welding surface, so as to improving the infiltration of the solder solution. Experimental results show that the ultrasonic welding-promoting technique can enhance the infiltration of the solder solution on the wire and the welding quality has been significantly improved.%利用超声波的机械作用,将超声波应用到焊接技术中,提出一种超声波助焊技术.超声波发生装置发出高频振荡信号,通过压电换能器转换成高频机械振荡而传播到介质,超声波在焊锡溶液中向前辐射,产生较强的压力,使焊锡溶液在瞬间有较大的振荡速度,降低焊锡溶液的表面张力,确保焊锡溶液在被焊接物表面顺利扩展、流动、浸润,提高焊锡溶液的浸润度.实验结果表明,超声助焊能明显提高焊锡对导线的浸润,提高导线焊接质量.

  2. 中国古青铜器表面富锡铜鎏镀及鎏焊的工艺探索第三部分——鎏焊%Technological study on amalgam coating and brazing of tin-rich copper on surface of bronze wares of ancient China——Part Ⅲ.Amalgam brazing

    Institute of Scientific and Technical Information of China (English)

    吴元康; 储荣邦

    2012-01-01

    Amalgam brazing is derived from amalgam coating. The definition, characteristics, application, and significance of amalgam brazing were expatiated. A process of amalgam brazing for producing combined bronze wares was developed. The compositions of brazing material and flux were given. The operations of pretreatment, mercury removal by heating, and post-treatment were described. The implementation of amalgam coating and brazing processes was introduced taking the Western Han Dynasty's bronze cowry container with tribute-paying figures excavated in Yunnan as an example. The method for distinguishing whether an antique bronze ware is produced by cast welding after lost-wax casting or by copper brazing with separated small cast parts was presented.%鎏焊是从鎏镀衍生而来的.阐述了鎏焊的定义、特点、应用和意义.设计了用于制作组合青铜器的鎏焊工艺,给出了焊料、焊剂配方,说明了前处理、加热驱汞及后处理的操作方法.以西汉云南纳贡场面青铜贮贝器为例,介绍了鎏镀与鎏焊工艺的具体实施过程.提出了鉴别古青铜器是由失蜡铸造后铸焊而成还是由分铸小件铜焊而成的方法.

  3. Welding process

    International Nuclear Information System (INIS)

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

  4. Brazing of zirconia to titanium using Ag-Cu and Au-Ni filler alloys

    Directory of Open Access Journals (Sweden)

    Jean S. Pimenta

    2013-12-01

    Full Text Available Advanced ceramic is usually joined to metal by the well-known direct brazing process, where costly active filler alloys can be considered a limitation. Brazing using active-metal-free filler alloy as insert between the joint components is an attempt to overcome it. The active metal diffusion from the titanium member through the bulk of molten filler to the ceramic was responsible to produce an active filler alloy in loco and promote reduction of the zirconium oxide to improve wetting on the ceramic surface. Unalloyed titanium was joined in a high-vacuum furnace (<3x10-5 mbar to yttria-tetragonal zirconia polycristals (Y-TZP and zirconia partially stabilized with magnesia (Mg-PSZ, where commercial fillers Ag-28Cu and Au-18Ni with respective thermal cycles were evaluated. Helium gas leak detection test was performed at the ceramic/metal interface at room temperature; samples from reliable vacuum tight joints were examined by microstructural analysis techniques and energy dispersive X-ray analysis at the joint cross-section. Tight joints were produced with eutectic Ag-Cu filler, revealing an intermetallic layer and a dark reaction layer near the ceramic surface; titanium diffusion was efficient for superficial chemical interactions between individual components. Brazing joints were also tested using three-point flexure testing.

  5. Mechanical Design, Brazing and Assembly Procedures of the LINAC4 RFQ

    CERN Document Server

    Mathot, S; Briswalter, A; Callamand, Th; Carosone, J; Favre, N; Geisser, J M; Lombardi, A; Maire, V; Malabaila, M; Pugnat, D; Richerot, Ph; Riffaut, B; Rossi, C; Timmins, M; Vacca, A; Vandoni, G; Vretenar, M

    2010-01-01

    The Linac4 RFQ will accelerate the H- beam from the ion source to the energy of 3 MeV. The RFQ is composed of three sections of one meter each, assembled by means of ultra high vacuum flanges and adjustable centring rings. The complete 3-m long RFQ will be supported isostatically over 3 points like a simple beam in order to minimise the maximum deflection. The ridge line, used to feed the RF power into the RFQ, will be supported via springs and its position adjusted in such way that no strain is introduced into the RFQ at the moment of its connection. The mechanical design has been done at CERN where the modules are completely manufactured, heat treated and brazed also. In that way, all of the processes are carefully controlled and the influence, notably of the heat treatments, has been understood in a better way. Since 2002 several four vanes RFQ modules have been brazed at CERN for the TRASCO and IPHI projects. A two-step brazing procedure has been tested. This technique is actually used for the assembly of...

  6. Residual stress in a laser welded EUROFER blanket module assembly using non-destructive neutron diffraction techniques

    CERN Document Server

    Hughes, D J; Heeley, E L

    2014-01-01

    Whilst the structural integrity and lifetime considerations in welded joints for blanket modules can be predicted using finite element software, it is essential to prove the validity of these simulations. This paper provides detailed analysis for the first time, of the residual stress state in a laser-welded sample with integral cooling channels. State-of-the-art non-destructive neutron diffraction was employed to determine the triaxial stress state and to understand microstructural changes around the heat affected zone. Synchrotron X-ray diffraction was used to probe the variation of strain-free lattice reference parameter around the weld zone allowing correction of the neutron measurements. This paper details an important experimental route to validation of predicted stresses in complex safety-critical reactor components for future applications.

  7. Control of weld quality in large welded populations

    International Nuclear Information System (INIS)

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

  8. Limitation of sheet metal welding——CMT cool metal transition technique%薄板焊接的极限——CMT冷金属过渡焊接技术

    Institute of Scientific and Technical Information of China (English)

    朱宇虹; 耿志卿

    2011-01-01

    在焊接不同壁厚的零部件时,要求具有良好焊缝厚度的厚工件要过渡到薄工件,并且在焊缝厚度过渡区仅有少量的热传导.许多材料无法承受焊接过程中持续不断的热量输入,为了避免熔滴穿透,实现无飞溅熔滴过渡和良好的冶金连接,就必须降低热输入量,在这种要求下,传统的气体保护焊接已经无能为力,而CMT技术实现了这种可能.相对于传统的MIG/MAG焊接过程而言,CMT技术的电弧温度和熔滴温度比较"冷".其特点是冷热循环交替,从而实现焊接机器人在MIG/MAG焊接中的无飞溅焊接以及钎焊0.3 mm超薄板.CMT技术的焊接系统适用于任何薄板、超薄板以及MIG钎焊镀锌板、碳钢与铝板的连接.%Welding of different thickness of the parts,the required thickness of the thick seam with good jobs to the transition to the thin piece,and the thickness of the transition zone in the weld with only a small amount of heat conduction.Some material couldn't help to endure the heating input continually,for avoiding welding penetrate and realize no spatter welding and to get well metal connection,it is necessary to reduce heating input value,CMT technique can satisfied it. Contrast with the traditional MIG/MAG welding technique,the arc temperature and melt spot temperature is lower. Circulate and alternate between cool and hot,consequently robot can realize no spatter welding and brazing sheet only 0.3 mm thickness using MIG/MAG welding technique. CMT technique adapt to welding sheet metal,brazing sheet with zinc coating,welding between carbon steel and aluminum sheet.

  9. Laser brazing with filler wire for galvanized steel sheets

    Institute of Scientific and Technical Information of China (English)

    Feng Xiaosong; Li Liqun; Chen Yanbin; Zhou Shanbao

    2005-01-01

    The process properties and interface behavior of CO2 laser brazing with automatic wire feed for galvanized steel sheets were investigated , in which the brazing filler metal was CuSi3 and no flux was used. As to the appearance quality of the brazing seams, the roles of the processing parameters, such as brazing speed, wire feeding rate, inclination and feeding direction of the wire, laser power, spot diameter and heating position, were assessed. The further investigation indicates that the behavior of the active elements Si, Mn and Zn are significantly influenced by energy input. At the interface, the microstructure of the base metal was composed of columnar crystals and the acicalar α solid solution was found on the filler metal side.

  10. COMPARATION BETWEEN NONDESTRUCTIVE TESTING METHODS FOR THE ALUMINIUM BRAZED PIECES

    Directory of Open Access Journals (Sweden)

    Dan NIŢOI

    2014-05-01

    Full Text Available Presented paper refers to different control methods used in aluminium brazed joining because of possible defects. Low joining complexity permits exact damages position in relation with materials geometry.

  11. Comparison of brazed joints made with BNi-1 and BNi-7 nickel-base brazing alloys

    Directory of Open Access Journals (Sweden)

    Zorc, Borut

    2000-04-01

    Full Text Available Kinetics of the processes are different with different types of brazing alloys. Precipitation processes in the parent metal close to the brazing gap are of great importance. They control the mechanical properties of the joint area when the brittle eutectic has disappeared from the gap. A comparative study of brazed joints on austenitic stainless alloys made with BNi-7 (Ni-P type and BNi-1 (Ni-Si-B type brazing alloys was made. Brazing alloys containing phosphorus behave in a different manner to those containing boron.

    Las aleaciones de níquel se producen mediante tres sistemas de aleación: Ni-P, Ni-Si y Ni-B. Durante las reacciones metalúrgicas con el metal de base, la eutéctica frágil en la separación soldada puede transformarse en la solución dúctil-sólida con todas aleaciones. La cinética del proceso varía según el tipo de aleación. Los procesos de precipitación en el metal de base cerca de la separación soldada son de mucha importancia, ya que controlan las propiedades mecánicas de la área de unión después de desaparecer la eutéctica frágil de la separación. Se ha hecho un análisis comparativo de uniones soldadas en aleaciones austeníticas inoxidables realizadas con aleaciones BNi-7 (tipo Ni-P y BNi-1 (tipo Ni-Si-B. Las aleaciones que contienen fósforo se comportan de una manera diferente, tanto con el cambio de la eutéctica a la solución sólida, como con los procesos de precipitación en el metal de base cerca de la unión soldada.

  12. Issues of low activation brazing of SiC f/SiC composites by using alloys without free silicon

    Science.gov (United States)

    Riccardi, B.; Nannetti, C. A.; Petrisor, T.; Woltersdorf, J.; Pippel, E.; Libera, S.; Pilloni, L.

    2004-08-01

    The paper presents a novel low activation brazing technique for SiC f/SiC composites. The brazing alloy does not contain free silicon and is based on the use of a Si-44Cr at.% eutectic and the intermetallic CrSi 2 (melting temperatures 1390 and 1490 °C, respectively). These are advantageous because the melting point is low enough to avoid degradation of the advanced fibres and of the interphases in the composite, and the Si-Cr intermetallics are chemically compatible with silicon carbide. Both the eutectic and the intermetallic were prepared before brazing operations by melting a Si-Cr mixture. The joining was performed under vacuum (about 10 -4 Pa). Systematic investigations of the microstructure and of the nanochemistry (TEM, EELS, ELNES) of the Si-Cr joints reveal that direct chemical Si-Si, Cr-C and Si-Cr bonds across the interface are responsible for the adhesion: the interfaces were proved to be nearly atomically sharp and adhesive. Altogether, this brazing procedure enables joints with sufficient strength and with a microstructure comparable with that of the starting powders to be obtained.

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

    International Nuclear Information System (INIS)

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

  14. Magnetic Pulse Welding Technology

    OpenAIRE

    Ahmad K. Jassim

    2011-01-01

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

  15. Inhibition of the formation of intermetallic compounds in aluminum-steel welded joints by friction stir welding

    OpenAIRE

    Torres López, Edwar A.; Ramirez, Antonio J.

    2015-01-01

    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 u...

  16. Annular beam shaping system for advanced 3D laser brazing

    Science.gov (United States)

    Pütsch, Oliver; Stollenwerk, Jochen; Kogel-Hollacher, Markus; Traub, Martin

    2012-10-01

    As laser brazing benefits from advantages such as smooth joints and small heat-affected zones, it has become established as a joining technology that is widely used in the automotive industry. With the processing of complex-shaped geometries, recent developed brazing heads suffer, however, from the need for continuous reorientation of the optical system and/or limited accessibility due to lateral wire feeding. This motivates the development of a laser brazing head with coaxial wire feeding and enhanced functionality. An optical system is designed that allows to generate an annular intensity distribution in the working zone. The utilization of complex optical components avoids obscuration of the optical path by the wire feeding. The new design overcomes the disadvantages of the state-of-the-art brazing heads with lateral wire feeding and benefits from the independence of direction while processing complex geometries. To increase the robustness of the brazing process, the beam path also includes a seam tracking system, leading to a more challenging design of the whole optical train. This paper mainly discusses the concept and the optical design of the coaxial brazing head, and also presents the results obtained with a prototype and selected application results.

  17. Brazed aluminum, Plate-fin heat exchangers for OTEC

    Energy Technology Data Exchange (ETDEWEB)

    Foust, H.D.

    1980-12-01

    Brazed aluminum plate-fin heat exchangers have been available for special applications for over thirty years. The performance, compactness, versatility, and low cost of these heat exchangers has been unequaled by other heat exchanger configuration. The application of brazed aluminum has been highly limited because of necessary restrictions for clean non-corrosive atmospheres. Air and gas separation have provided ideal conditions for accepting brazed aluminum and in turn have benefited by the salient features of these plate-fin heat exchangers. In fact, brazed aluminum and cryogenic gas and air separation have become nearly synonymous. Brazed aluminum in its historic form could not be considered for a seawater atmosphere. However, technology presents a new look of significant importance to OTEC in terms of compactness and cost. The significant technological variation made was to include one-piece hollow extensions for the seawater passages. Crevice corrosion sites are thereby entirely eliminated and pitting corrosion attack will be controlled by an integral and sacrificial layer of a zinc-aluminum alloy. This paper on brazed aluminum plate-fin heat exchangers for OTEC will aquaint the reader with the state-of-art and variations suggested to qualify this form of aluminum for seawater use. In order to verify the desirable cost potential for OTEC, Trane teamed with Westinghouse to perform an OTEC system analysis with this heat exchanger. These results are very promising and reported in detail elsewhere.

  18. Brazing of Stainless Steel to Yttria-Stabilized Zirconia Using Gold-Based Brazes for Solid Oxide Fuel Cell Applications

    Science.gov (United States)

    Singh, M.; Shpargel, T. P.; Asthana, R.

    2007-01-01

    Two gold-base active metal brazes (gold-ABA and gold-ABA-V) were evaluated for oxidation resistance to 850 C, and used to join yttria-stabilized zirconia (YSZ) to a corrosion-resistant ferritic stainless steel for possible use in solid oxide fuel cells. Thermogravimetric analysis and optical microscopy and scanning electron microscopy coupled with energy-dispersive spectroscopy were used to evaluate the braze oxidation behavior, and microstructure and composition of the YSZ/braze/steel joints. Both gold-ABA and gold-ABA-V exhibited nearly linear oxidation kinetics at 850 C, with gold-ABA-V showing faster oxidation than gold-ABA. Both brazes produced metallurgically sound YSZ/steel joints due to chemical interactions of Ti and V with the YSZ and steel substrates.

  19. Brazing open cell reticulated copper foam to stainless steel tubing with vacuum furnace brazed gold/indium alloy plating

    Science.gov (United States)

    Howard, Stanley R.; Korinko, Paul S.

    2008-05-27

    A method of fabricating a heat exchanger includes brush electroplating plated layers for a brazing alloy onto a stainless steel tube in thin layers, over a nickel strike having a 1.3 .mu.m thickness. The resultant Au-18 In composition may be applied as a first layer of indium, 1.47 .mu.m thick, and a second layer of gold, 2.54 .mu.m thick. The order of plating helps control brazing erosion. Excessive amounts of brazing material are avoided by controlling the electroplating process. The reticulated copper foam rings are interference fit to the stainless steel tube, and in contact with the plated layers. The copper foam rings, the plated layers for brazing alloy, and the stainless steel tube are heated and cooled in a vacuum furnace at controlled rates, forming a bond of the copper foam rings to the stainless steel tube that improves heat transfer between the tube and the copper foam.

  20. Steel welding.

    OpenAIRE

    Kučera, Marek

    2011-01-01

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

  1. 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…

  2. Mechanism of laser welding on dissimilar metals between stainless steel and W-Cu alloy

    Institute of Scientific and Technical Information of China (English)

    Kai Chen; Zhiyong Wang; Rongshi Xiao; Tiechuan Zuo

    2006-01-01

    @@ CO2 laser is employed to join a piece of powder metallurgical material (PMM) to a stainless steel in butt joint welding mode. The powder Ni35, as a filler powder, is used. The weld metal comes from three parts of stainless steel, powder Ni35, and Cu in W-Cu PMM. It is indicated that some parts of the W-Cu base metal are heated by laser and the metal Cu at the width of 0.06-0.12 mm from the edge is melted into the melting pool in the laser welding process. The formation of firm weld joint is just because that the melting liquid metal could fill the position occupied by metal Cu and surround the metal W granules fully. The analysis results indicate that the mechanism of the laser welding for stainless steel and W-Cu alloy is a special mode of fusion-brazing welding.

  3. Laser-welded Dissimilar Steel-aluminum Seams for Automotive Lightweight Construction

    Science.gov (United States)

    Schimek, M.; Springer, A.; Kaierle, S.; Kracht, D.; Wesling, V.

    By reducing vehicle weight, a significant increase in fuel efficiency and consequently a reduction in CO 2 emissions can be achieved. Currently a high interest in the production of hybrid weld seams between steel and aluminum exists. Previous methods as laser brazing are possible only by using fluxes and additional materials. Laser welding can be used to join steel and aluminum without the use of additives. With a low penetration depth increases in tensile strength can be achieved. Recent results from laser welded overlap seams show that there is no compromise in strength by decreasing penetration depth in the aluminum.

  4. EMAT weld inspection and weld machine diagnostic system for continuous coil processing lines

    Science.gov (United States)

    Latham, Wayne M.; MacLauchlan, Daniel T.; Geier, Dan P.; Lang, Dennis D.

    1996-11-01

    Weld breaks of steel coil during cold rolling and continuous pickling operations are a significant source of lost productivity and product yield. Babcock and Wilcox Innerspec Technologies has developed a weld process control system which monitors the key variables of the welding process and determines the quality of the welds generated by flash butt welding equipment. This system is known as the Temate 2000 Automated Flash Butt Weld Inspection and Weld Machine Diagnostic System. The Temate 2000 system utilizes electro- magnetic acoustic transducer (EMAT) technology as the basis for performing on-line, real-time, nondestructive weld quality evaluation. This technique accurately detects voids, laps, misalignment and over/under trim conditions in the weld. Results of the EMAT weld inspection are immediately presented to the weld machine operator for disposition. Welding process variables such as voltage, current, platen movements and upset pressures are monitored and collected with the high speed data acquisition system. This data is processed and presented in real-time display to indicate useful welding process information such as platen crabbing, upset force, peak upset current, and many others. Alarming for each variable is provided and allows detailed maintenance reports and summary information to be generated. All weld quality and process parameter data are stored, traceable to each unique weld, and available for post process evaluation. Installation of the Temate 2000 system in a major flat rolled steel mill has contributed to near elimination of weld breakage and increased productivity at this facility.

  5. 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.

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

    International Nuclear Information System (INIS)

    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

  7. Magnetic Pulse Welding Technology

    Directory of Open Access Journals (Sweden)

    Ahmad K. Jassim

    2011-12-01

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

  8. Laser welding of venotomies.

    Science.gov (United States)

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

    1986-08-01

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

  9. CIVA workstation for NDE: mixing of NDE techniques and modeling

    Energy Technology Data Exchange (ETDEWEB)

    Benoist, P.; Besnard, R. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Procedes et Systemes Avances; Bayon, G. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Reacteurs Experimentaux; Boutaine, J.L. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. des Applications et de la Metrologie des Rayonnements Ionisants

    1994-12-31

    In order to compare the capabilities of different NDE techniques, or to use complementary inspection methods, the same components are examined with different procedures. It is then very useful to have a single evaluation tool allowing direct comparison of the methods: CIVA is an open system for processing NDE data; it is adapted to a standard work station (UNIX, C, MOTIF) and can read different supports on which the digitized data are stored. It includes a large library of signal and image processing methods accessible and adapted to NDE data (filtering, deconvolution, 2D and 3D spatial correlations...). Different CIVA application examples are described: brazing inspection (neutronography, ultrasonic), tube inspection (eddy current, ultrasonic), aluminium welds examination (UT and radiography). Modelling and experimental results are compared. 16 fig., 7 ref.

  10. Resistance welding

    DEFF Research Database (Denmark)

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

    2003-01-01

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

  11. Method of temperature rising velocity and threshold control of electron beam brazing

    Institute of Scientific and Technical Information of China (English)

    Xuedong Wang; Shun Yao

    2005-01-01

    In order to accommodate electron beam to the brazing of the joints with various curve shapes and the brazing of thermo sensitive materials, the method of electron beam scanning and brazing temperature control was developed, in which electron beam was controlled to scan according to predefined scanning track, and the actual temperature rising velocity of the brazed seam was limited in an allowed scope by detecting the brazed seam temperature, calculating the temperature rising velocity and adjusting the beam current during the brazing process; in addition, through the setting of the highest allowed temperature, the actual temperature of the brazed seam could be controlled not exceeding the threshold set value, and these two methods could be employed alone or jointly. It is shown that high precision temperature control in electron beam brazing could be realized and the productivity be increased by the proposed method.

  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. Primary water stress corrosion cracks in nickel alloy dissimilar metal welds: Detection and sizing using established and emerging nondestructive examination techniques

    International Nuclear Information System (INIS)

    The U.S. Nuclear Regulatory Commission has established the Program to Assess the Reliability of Emerging Nondestructive Techniques (PARENT) as a follow-on to the international cooperative Program for the Inspection of Nickel Alloy Components (PINC). The goal of PINC was to evaluate the capabilities of various nondestructive evaluation (NDE) techniques to detect and characterize surface-breaking primary water stress corrosion cracks in dissimilar-metal welds (DMW) in bottom-mounted instrumentation (BMI) penetrations and small-bore (∼400-mm diameter) piping components. A series of international blind round-robin tests were conducted by commercial and university inspection teams. Results from these tests showed that a combination of conventional and phased-array ultrasound techniques provided the highest performance for flaw detection and depth sizing in dissimilar metal piping welds. The effective detection of flaws in BMIs by eddy current and ultrasound shows that it may be possible to reliably inspect these components in the field. The goal of PARENT is to continue the work begun in PINC and apply the lessons learned to a series of open and blind international round-robin tests that will be conducted on a new set of piping components including large-bore (∼900-mm diameter) DMWs, small-bore DMWs, and BMIs. Open round-robin testing will engage universities and industry worldwide to investigate the reliability of emerging NDE techniques to detect and accurately size flaws having a wide range of lengths, depths, orientations, and locations. Blind round-robin testing will invite testing organizations worldwide, whose inspectors and procedures are certified by the standards for the nuclear industry in their respective countries, to investigate the ability of established NDE techniques to detect and size flaws whose characteristics range from easy to very difficult to detect and size. This paper presents highlights of PINC and reports on the plans and progress for

  14. Effects of Rare Earths on Properties of Ti-Zr-Cu-Ni Base Brazing Filler Alloys

    Institute of Scientific and Technical Information of China (English)

    Ma Tianjun; Kang Hui; Wu Yongqin; Qu Ping

    2004-01-01

    The effects of the addition of rare earths on the properties of Ti-Zr-Cu-Ni base brazing filler alloys and the mechanical microstructure and properties were studied for the brazed-joints in the vacuum brazing of TC4 by comparing synthetical properties of two kinds of filler metals.The results indicate that the filler metals added with rare earths have lower melting point, better wettability and higher mechanical properties in the brazing joints.

  15. Local zone wise elastic and plastic properties of electron beam welded Ti-6Al-4V alloy using digital image correlation technique: A comparative study between uniform stress and virtual fields method

    Science.gov (United States)

    Saranath, K. M.; Ramji, M.

    2015-05-01

    Joining of materials using welding results in the formation of material zones with varying microstructure across the weld. Extraction of the mechanical properties of those individual heterogeneous zones are important in designing components and structures comprised of welds. In this study, the zone wise local extraction of the elastic and plastic properties of an electron beam welded Ti-6Al-4V titanium alloy has been carried out using both the uniform stress method (USM) and the virtual fields method (VFM) involving digital image correlation (DIC) technique. The surface strain field obtained using DIC technique from a transverse weld specimen tensile testing is used for extracting the zone wise strain evolution. Initially, using uniform stress assumption, zone wise full range stress-strain curves are extracted. In USM methodology, the elastic and plastic material models are fitted to the zone wise stress-strain curves and required parameters are extracted from it. But inherent disadvantage is lot of images need to be processed for the parameter extraction. Recently, VFM is gaining lot of popularity in characterization domain as it is robust, accurate and faster. VFM is based on the principle of virtual work where, the weak form of local equilibrium equations and kinematically admissible virtual displacement fields are utilized for parameter extraction. Hollomon's power law is used here as the hardening rule. Young's modulus, Poisson's ratio, yield stress, strength coefficient and strain hardening exponent are the parameters extracted zone wise using both USM and VFM. A Vicker's microhardness measurement is also conducted across the weld zone towards mapping the strength behavior. Fusion zone has reported higher yield strength, strength coefficient and Poisson's ratio. Young's modulus value is found decreasing from base metal towards the fusion zone. The trend observed in parameter variation across the weld zone obtained by both USM and VFM compares very well. Due

  16. Microstructure and fatigue properties of Mg-to-steel dissimilar resistance spot welds

    International Nuclear Information System (INIS)

    Highlights: ► Mg/steel dissimilar spot weld had the same fatigue strength as Mg/Mg similar weld. ► Crack propagation path of Mg/Mg and Mg/steel welds was the same. ► Penetration of Zn into the Mg base metal led to crack initiation of Mg/steel weld. ► HAZ weakening and stress concentration led to crack initiation of Mg/Mg weld. -- Abstract: The structural application of lightweight magnesium alloys in the automotive industry inevitably involves dissimilar welding with steels and the related durability issues. This study was aimed at evaluating the microstructural change and fatigue resistance of Mg/steel resistance spot welds, in comparison with Mg/Mg welds. The microstructure of Mg/Mg spot welds can be divided into: base metal, heat affected zone and fusion zone (nugget). However, the microstructure of Mg/steel dissimilar spot welds had three different regions along the joined interface: weld brazing, solid-state joining and soldering. The horizontal and vertical Mg hardness profiles of Mg/steel and Mg/Mg welds were similar. Both Mg/steel and Mg/Mg welds were observed to have an equivalent fatigue resistance due to similar crack propagation characteristics and failure mode. Both Mg/steel and Mg/Mg welds failed through thickness in the magnesium sheet under stress-controlled cyclic loading, but fatigue crack initiation of the two types of welds was different. The crack initiation of Mg/Mg welds was occurred due to a combined effect of stress concentration, grain growth in the heat affected zone (HAZ), and the presence of Al-rich phases at HAZ grain boundaries, while the penetration of small amounts of Zn coating into the Mg base metal stemming from the liquid metal induced embrittlement led to crack initiation in the Mg/steel welds.

  17. Technical specifications on the welding in fuel reprocessing plants

    Energy Technology Data Exchange (ETDEWEB)

    Karino, Motonobu; Uryu, Mitsuru; Matsui, N.; Nakazawa, Fumio; Imanishi, Makoto; Koizumi; Kazuhiko; Sugawara, Junichi; Tanaka, Hideo

    1999-04-01

    The past specifications SGN of the welding in JNC was reexamined for the reprocessing plants in order to further promote the quality control. The specification first concerns the quality of raw materials, items of the quality tests, material management, and qualification standards of the welders. It extends over details of the welding techniques, welding design, welding testings, inspection and the judgment standards. (H. Baba)

  18. Estimation of weld nugget temperature by thermography method in resistance projection welding process

    International Nuclear Information System (INIS)

    In the Pressurized Heavy Water Reactor (PHWR) fuel manufacturing, zirconium alloy appendages like spacer and bearing pads are welded to the thin wall zirconium alloy fuel tubes by using resistance projection welding process. Out of many joining processes available, resistance-welding process is reliable, environment friendly and best suitable for mass production applications. In the fuel assembly, spacer pads are used to get the required inter-element spacing and Bearing pads are used to get the required load-bearing surface for the fuel assembly. Performance of the fuel assembly in the reactor is greatly influenced by these weld joint's quality. Phase transformation from α to β phase is not acceptable while welding these tiny appendages. At present only destructive metallography test is available for this purpose. This can also be achieved by measuring weld nugget temperature where in the phase transformation temperature for zirconium alloy material is 853oC. The temperature distribution during resistance welding of tiny parts cannot be measured by conventional methods due to very small space and short weld times involved in the process. Shear strength, dimensional accuracy and weld microstructures are some of the key parameters used to measure the quality of appendage weld joints. Weld parameters were optimized with the help of industrial experimentation methodology. Individual projection welding by split electrode concept, and during welding on empty tube firm support is achieved on inner side of the tube by using expandable pneumatic mandrel. In the present paper, an attempt was made to measure the weld nugget temperature by thermography technique and is correlated with standard microstructures of zirconium alloy material. The temperature profiles in the welding process are presented for different welding conditions. This technique has helped in measuring the weld nugget temperature more accurately. It was observed that in the present appendage welding

  19. Welding of plastic parts of electric pumps

    Energy Technology Data Exchange (ETDEWEB)

    Dreishner, E.P.; Belen' kii, M.Kh.

    1987-03-01

    The authors propose a new welding technique and machinery for the thermal contact welding thermoplastic parts of electric oil well pumps which efficiently creates welds of higher quality than those resulting from ultrasonic welding and also permits the use of cheaper and more readily available thermoplastics such as polyethylene and polypropylene which do not lend themselves to ultrasonic welding. The annual savings to the industry as a result of the implementation of their technique, and of the substitution of polypropylene for polyamide, amounts to 150,000 rubles.

  20. Microstructural Changes in Brazing Sheet due to Solid-Liquid Interaction

    NARCIS (Netherlands)

    Wittebrood, A.J.

    2009-01-01

    Aluminium brazing sheet is the material of choice to produce automotive heat exchangers. Although in Dutch the official translation of aluminium brazing sheet is “aluminium hardsoldeerplaat” the English name is used in the industry. Aluminium brazing sheet is basically a sandwich material and consis

  1. [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.

  2. High-temperature brazing for reliable tungsten-CFC joints

    International Nuclear Information System (INIS)

    The joining of tungsten and carbon-based materials is demanding due to the incompatibility of their chemical and thermophysical properties. Direct joining is unfeasible by the reason of brittle tungsten carbide formation. High-temperature brazing has been investigated in order to find a suitable brazing filler metal (BFM) which successfully acts as an intermediary between the incompatible properties of the base materials. So far only low Cr-alloyed Cu-based BFMs provide the preferential combination of good wetting action on both materials, tolerable interface reactions, and a precipitation free braze joint. Attempts to implement a higher melting metal (e.g. Pd, Ti, Zr) as a BFM have failed up to now, because the formation of brittle precipitations and pores in the seam were inevitable. But the wide metallurgical complexity of this issue is regarded to offer further joining potential

  3. Alloy 800 welding experience at UKAEA Springfields

    International Nuclear Information System (INIS)

    Investigatins into the welding of alloy 800 at the Reactor Fuel Element Laboratories, Springfields, commenced about three years ago following an extended development programme on tube to tube plate welding of low alloy and stainless steels for the Prototype Fast Reactor. The techniques and approach developed for critical fuel element welding applications had proved equally suitable for the precision welding requirements on the much heavier sections of heat exchangers. It had been demonstrated that the same control of weld quality and profile could be achieved with consistency and the permissible range of critical parameters could be readily defined. Because of this, development work was continued to include other materials, such as alloy 800, which might be of potential use. The tungsten inert gas (T.I.G.) arc welding process is used, and the equipment, including the control system, is described. Tube to tube-plate welding, and tube to tube butt welding, are discussed. (author)

  4. 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)

  5. Optimization of weld bead geometry in laser welding with filler wire process using Taguchi’s approach

    Science.gov (United States)

    dongxia, Yang; xiaoyan, Li; dingyong, He; zuoren, Nie; hui, Huang

    2012-10-01

    In the present work, laser welding with filler wire was successfully applied to joining a new-type Al-Mg alloy. Welding parameters of laser power, welding speed and wire feed rate were carefully selected with the objective of producing a weld joint with the minimum weld bead width and the fusion zone area. Taguchi approach was used as a statistical design of experimental technique for optimizing the selected welding parameters. From the experimental results, it is found that the effect of welding parameters on the welding quality decreased in the order of welding speed, wire feed rate, and laser power. The optimal combination of welding parameters is the laser power of 2.4 kW, welding speed of 3 m/min and the wire feed rate of 2 m/min. Verification experiments have also been conducted to validate the optimized parameters.

  6. TOFD Technique Applied to Weld Inspection of Special Strartures%TOFD技术在特殊结构焊缝检测中的应用

    Institute of Scientific and Technical Information of China (English)

    洪作友; 唐兴军

    2009-01-01

    The working principle of TOFD technique was described. The testing effects were compared between radiographic testing and ultrasonic testing method for the detection of volute plate and seam weld. The actual weld section showed that the planar defects, which were difficult to detect by conventional ultrasonic testing and radiographic testing method, were easy to TOFD technique, but there was some error for the porosity, inclusions and such as volume-like defects between TOFD testing and actual section. Due to its high defect detection rate,sensitive to planar defects, less limits by direction, fast testing speed, intuitive scanning image and with no radiation and so on, TOFD technique had good prospect on the safety evaluation at petrochemical installations and so on special equipments.%叙述了TOFD技术的工作原理.在蜗壳焊缝试板及焊缝检测中将超声波和射线检测技术进行了对比.焊缝的缺陷解剖试验表明,TOFD技术能检出常规超声和射线检测方法难以检出的平面状缺陷,对气孔、夹杂等体积状缺陷的检测结果与实际解剖结果有出入.鉴于TOFD技术缺陷检出率高,对面状缺陷灵敏、不受方向性限制、检测速度快、扫描图显示直观并且无辐射等优点,因此在石化装置等在役特种设备的安全评定中具有很好的推广价值.

  7. Inspection and Repair Techniques and Strategies for Alloy 600 PWSCC in Reactor Vessel Head CRD Nozzles and Welds

    International Nuclear Information System (INIS)

    As a result of the Alloy 600 PWSCC CRD nozzle leaks discovered in the fall of 2000 and spring of 2001 in several US plants, the NRC has recommended a more pro-active effort by U.S. utilities to inspect similarly susceptible nozzles in all US plants. The primary safety concern is circumferential cracks that can permit the nozzle to separate from the head at high velocity and produce a large-break leak in the reactor vessel. A secondary concern is head leakage from any through-wall cracks in the nozzle or J-groove weld area. Although the fundamental weld and seal design are similar for all US PWR plants, the various surrounding geometry and repair probability considerations require multiple inspection and repair alternatives. Geometry issues include the head insulation design that influences the ability to perform visual examinations from above the head, and the presence or absence of thermal sleeves and funnels governing the type of NDE probes than can be used. Repair probability considerations primarily include the likelihood for repair of a small or large number of nozzles and the length of time the repair must last before a head replacement. This paper discusses the various inspection and repair alternatives offered by one service vendor and discusses a decision process for planning the inspection and repair effort. (authors)

  8. Study of the mechanical properties of welded joints by wet sub sea welding technique with tubular electrode; Estudo das propriedades mecanicas de juntas soldadas pela tecnica de soldagem subaquatica molhada com eletrodo tubular

    Energy Technology Data Exchange (ETDEWEB)

    Teichmann, Erwin Werner; Baixo, Carlos Eduardo Iconomos; Dutra, Jair Carlos [Santa Catarina Univ., Florianopolis, SC (Brazil). Dept. de Engenharia Mecanica. Lab. de Soldagem e Mecatronica - LABSOLDA]. E-mail: erwin@labsolda.ufsc.br; Santos, Valter Rocha dos [Centro Federal de Educacao Tecnologica (CEFET), Rio de Janeiro, RJ (Brazil); Teixeira, Jose Claudio [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas

    1997-07-01

    Some experiments conducted at LABSOLDA/UFSC - a welding laboratory of Santa Catarina Univ., Florianopolis, Brazil - in order to identify mechanical properties, weld bead geometry and the quantity and dimensions of pores in weld beads produced by sub sea wet FCAW are described. Welding in shallow water with power source adjusted to operate in constant current characteristic mode and a set of parameters to establish an open arc transfer mode it was obtained weld beads with regular geometry and an acceptable profile, with low level of defects incidence, no pores and crack free. The tenacity measured by Charpy tests (0C) was 34 J and hardness of 119 HV-10 measured by Vickers tests. The methodology used in the experiments and the results obtained are discussed in the paper. (author)

  9. Numerical simulation of filler metal droplets spreading in laser brazing

    Institute of Scientific and Technical Information of China (English)

    Yanbin Chen; Xiaosong Feng; Liqun Li

    2007-01-01

    A finite element model was constructed using a commercial software Fidap to analyze the Cu-base filler metal droplet spreading process in laser brazing, in which the temperature distribution, droplet geometry,and fluid flow velocity were calculated. Marangoni and buoyancy convection and gravity force were considered, and the effects of laser power and spot size on the spreading process were evaluated. Special attention was focused on the free surface of the droplet, which determines the profile of the brazing spot.The simulated results indicate that surface tension is the dominant flow driving force and laser spot size determines the droplet spreading domain.

  10. Numerical simulation of filler metal droplets spreading in laser brazing

    Science.gov (United States)

    Chen, Yanbin; Feng, Xiaosong; Li, Liqun

    2007-11-01

    A finite element model was constructed using a commercial software Fidap to analyze the Cu-base filler metal droplet spreading process in laser brazing, in which the temperature distribution, droplet geometry, and fluid flow velocity were calculated. Marangoni and buoyancy convection and gravity force were considered, and the effects of laser power and spot size on the spreading process were evaluated. Special attention was focused on the free surface of the droplet, which determines the profile of the brazing spot. The simulated results indicate that surface tension is the dominant flow driving force and laser spot size determines the droplet spreading domain.

  11. Investigation of Brazed Plate Heat Exchangers With Variable Chevron Angles

    Directory of Open Access Journals (Sweden)

    S. Muthuraman

    2013-08-01

    Full Text Available - Experiments to measure the condensation heat transfer coefficient and the pressure drop in brazed plate heat exchangers (BPHEs were performed with the refrigerants R410A and R22. Brazed plate heat exchangers with different chevron angles of 45°, 35°, and 20° were used. Varying the mass flux, the condensation temperature, and the vapor quality of the refrigerant, we measured the condensation heat transfer coefficient and the pressure drops. Both the heat transfer coefficient and the pressure drop increased proportionally with the mass flux and the vapor quality and inversely with the condensation temperature and the chevron angle.

  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. EFFECT OF MIG WELDING INPUT PROCESS PARAMETERS ON WELD BEAD GEOMETRY ON HSLA STEEL

    OpenAIRE

    MOHD. SHOEB; Prof. Mohd. Parvez; Prof. Pratibha Kumari

    2013-01-01

    The various welding parameters such as welding speed, voltage and gas flow rate were varied on HSLA steel and the effects of these parameters on weld bead geometry such as penetration, width & height have been studied. Mathematical equations have been developed using factorial technique. And the result of various effects are shown in tables. (Numerical Values).

  14. EFFECT OF MIG WELDING INPUT PROCESS PARAMETERS ON WELD BEAD GEOMETRY ON HSLA STEEL

    Directory of Open Access Journals (Sweden)

    MOHD. SHOEB

    2013-01-01

    Full Text Available The various welding parameters such as welding speed, voltage and gas flow rate were varied on HSLA steel and the effects of these parameters on weld bead geometry such as penetration, width & height have been studied. Mathematical equations have been developed using factorial technique. And the result of various effects are shown in tables. (Numerical Values.

  15. Towards Real Time Diagnostics of Hybrid Welding Laser/GMAW

    Energy Technology Data Exchange (ETDEWEB)

    Timothy Mcjunkin; Dennis C. Kunerth; Corrie Nichol; Evgueni Todorov; Steve Levesque; Feng Yu; Robert Danna Couch

    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.

  16. Towards real time diagnostics of Hybrid Welding Laser/GMAW

    Energy Technology Data Exchange (ETDEWEB)

    McJunkin, T. R.; Kunerth, D. C.; Nichol, C. I. [Idaho National Laboratory, Idaho Falls, ID 83415-3570 (United States); Todorov, E.; Levesque, S. [Edison Welding Institute, Columbus, OH (United States)

    2014-02-18

    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.

  17. Microwave-assisted brazing of alumina ceramics for electron tube applications

    Indian Academy of Sciences (India)

    2016-04-01

    Alumina was joined with alumina using microwave-assisted and conventional brazing methods at 960$^{\\circ}$C for 15 min using TiCuSil (68.8Ag–26.7Cu–4.5Ti in wt.%) as the brazing alloy. The brazed joints were characterizedby X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis, Vickers microhardness evaluation, brazing strength measurement and helium leak test. X-ray diffraction analysis confirmed the formationof Ti-based compounds at the substrate-filler alloy interfaces of the microwave and conventionally brazed joints. The elemental compositions at the joint cross-section were determined by energy dispersive X-ray analysis. Vickers microhardness measurement indicated reliable joint performance for the microwave-assisted brazed joints during actual application in an electron tube. Brazing strength measurement and helium leak test provided the evidence forgood alumina-alumina joint formation.

  18. Evolution of a Laser Hybrid Welding Map

    Science.gov (United States)

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

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

  19. Laser welding of thermoplastic materials.

    Science.gov (United States)

    Chipperfield, F A; Jones, I A

    2001-06-01

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

  20. The effect of thermal properties and weld efficiency on residual stresses in welding

    OpenAIRE

    E. Armentani; Esposito, R.; R. Sepe

    2007-01-01

    Purpose: A parametric model is adopted and the technique of element “birth and death” is used to estimate theeffect of thermal properties and weld efficiency on residual stresses in butt weld joints.Design/methodology/approach: Residual stresses and distortions on butt welded joints are numericallyevaluated by means of finite element method. The FE analysis allows to highlight and evaluate the stress fieldand its gradient around the fusion zone of welded joints, higher than any other located ...

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

    Directory of Open Access Journals (Sweden)

    Saritprava Sahoo

    2013-08-01

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

  2. Qualification of electron-beam welded joints between copper and stainless steel for cryogenic application

    Science.gov (United States)

    Lusch, C.; Borsch, M.; Heidt, C.; Magginetti, N.; Sas, J.; Weiss, K.-P.; Grohmann, S.

    2015-12-01

    Joints between copper and stainless steel are commonly applied in cryogenic systems. A relatively new and increasingly important method to combine these materials is electron-beam (EB) welding. Typically, welds in cryogenic applications need to withstand a temperature range from 300K down to 4K, and pressures of several MPa. However, few data are available for classifying EB welds between OFHC copper and 316L stainless steel. A broad test program was conducted in order to qualify this kind of weld. The experiments started with the measurement of the hardness in the weld area. To verify the leak-tightness of the joints, integral helium leak tests at operating pressures of 16 MPa were carried out at room- and at liquid nitrogen temperature. The tests were followed by destructive tensile tests at room temperature, at liquid nitrogen and at liquid helium temperatures, yielding information on the yield strength and the ultimate tensile strength of the welds at these temperatures. Moreover, nondestructive tensile tests up to the yield strength, i.e. the range in which the weld can be stressed during operation, were performed. Also, the behavior of the weld upon temperature fluctuations between room- and liquid nitrogen temperature was tested. The results of the qualification indicate that EB welded joints between OFHC copper and 316L stainless steel are reliable and present an interesting alternative to other technologies such as vacuum brazing or friction welding.

  3. 硬质合金刀具钎焊后性能变化的研究%Changes in properties of carbide cutting tools after being brazed

    Institute of Scientific and Technical Information of China (English)

    赵丽杰; 王贵成; 王冬

    2001-01-01

    对硬质合金刀具钎焊前后的硬度、裂纹形成及变化、焊缝质量和切削性能等进行了大量的试验研究.结果表明:硬质合金刀具钎焊后硬度下降范围在HRA1以内;采用延长钎焊后保温时间和增加补偿垫片均可以减少或避免刀具表面裂纹的产生;对18CrMnTi渗碳淬火齿轮(HRC55~58)单齿侧刃铣削中钎焊刀具的切削性能同机夹刀具相比无明显差异.它为硬质合金钎焊刀具在精密切削FMS和其他自动化加工中的广泛应用提供了实验和理论依据.%Presents the experimental tests run on hardness of carbide cutting tools before and after being brazed, initiation and propagation of cracks in them, quality of weld and cutting performance of these cutting tools, and the experimental test results which show that the reduction in hardness of carbide cutting tools after being brazed is within HRA1, the initiation of cracks in the surface of cutting tools can be reduced or eliminated by prolonging the holding time for the cutting tools after being brazed and adding shims, and the cutting performance of brazed cutting tools with single cutting edge made of 18CrMnTi is similar to that of fixed machining cutting tool.

  4. Enhanced corrosion protection by microstructural control of aluminium brazing sheet

    NARCIS (Netherlands)

    Norouzi Afshar, F.

    2013-01-01

    Aluminium brazing sheet is a sandwich material made out of two aluminium alloys (AA4xxx/AA3xxx) and is widely used in automotive heat exchangers. One of the main performance criteria for heat exchanger units is the lifetime of the product. The lifetime of the heat exchanger units is determined by th

  5. Resistance welding equipment manufacturing capability for exports

    International Nuclear Information System (INIS)

    Indian Pressurised Heavy Water Reactor (PHWR) fuel bundle is fully welded and is unique in its design. Appendage welding, end closure welding, and end plate welding is carried out using resistance welding technique. Out of many joining processes available, resistance-welding process is reliable, environment friendly and best suitable for mass production applications. Nuclear Fuel Complex (NFC), an industrial unit is established in Hyderabad, under the aegis of the Dept of Atomic Energy to manufacture fuel for Pressurised Heavy Water Reactors. From inception, NFC has given importance for self-reliance and indigenization with respect to manufacturing process and equipment. Sintering furnaces, centreless grinders, appendage-welding machines, end-closure welding equipment and end-plate welding equipments, which were initially imported, are either indigenized or designed and manufactured in house. NFC has designed, manufactured a new appendage-welding machine for manufacturing 37 element fuel bundles. Recently NFC has bagged an order from IAEA through international bidding for design, manufacture, supply, erection and commissioning of end-closure welding equipment. The paper gives in detail the salient features of these welding equipment. (author)

  6. Resistance welding equipment manufacturing capability for exports

    Energy Technology Data Exchange (ETDEWEB)

    Sastry, V.S.; Raju, Y.S.; Somani, A.K.; Setty, D.S.; Rameswara Raw, A.; Hermantha Rao, G.V.S.; Jayaraj, R.N. [Nuclear Fuel Complex, Dept. of Atomic Energy, Hyderbad (India)

    2010-07-01

    Indian Pressurised Heavy Water Reactor (PHWR) fuel bundle is fully welded and is unique in its design. Appendage welding, end closure welding, and end plate welding is carried out using resistance welding technique. Out of many joining processes available, resistance-welding process is reliable, environment friendly and best suitable for mass production applications. Nuclear Fuel Complex (NFC), an industrial unit is established in Hyderabad, under the aegis of the Dept of Atomic Energy to manufacture fuel for Pressurised Heavy Water Reactors. From inception, NFC has given importance for self-reliance and indigenization with respect to manufacturing process and equipment. Sintering furnaces, centreless grinders, appendage-welding machines, end-closure welding equipment and end-plate welding equipments, which were initially imported, are either indigenized or designed and manufactured in house. NFC has designed, manufactured a new appendage-welding machine for manufacturing 37 element fuel bundles. Recently NFC has bagged an order from IAEA through international bidding for design, manufacture, supply, erection and commissioning of end-closure welding equipment. The paper gives in detail the salient features of these welding equipment. (author)

  7. Fundamentals of evaluation and diagnostics of welded structures

    CERN Document Server

    Nedoseka, Anatoliy Yakovlevich

    2012-01-01

    Provides an essential guide to the key principles and problems involved in the analysis of welded structures. This title discusses design issues, key equations and calculations, and the effects of varied heat sources in relation to the temperature field in welding. It goes on to explore welding stresses and strains.$bFundamentals of evaluation and diagnostics of welded structures provides an essential guide to the key principles and problems involved in the analysis of welded structures. Chapter one discusses design issues, key equations and calculations, and the effects of varied heat sources in relation to the temperature field in welding. Chapter two goes on to explore welding stresses and strains. Fracture mechanics and the load-carrying capacity of welded structures are the focus of chapter three. Chapter four considers diagnostics and prediction of the residual life of welded structures, whilst acoustic emission techniques for the analysis of welded structures are reviewed in Chapter five. Finally, chap...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-01-01

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

  9. Vacuum brazing of TiAl48Cr2Nb2 casting alloys based on TiAl (γ intermetallic compound

    Directory of Open Access Journals (Sweden)

    Z. Mirski

    2010-01-01

    Full Text Available A growing interest in modern engineering materials characterised by increasingly better operational parameters combined with a necessity to obtain joints of such materials representing good operation properties create important research and technological problems of today. These issues include also titanium joints or joints of titanium alloys based on intermetallic compounds. Brazing is one of the basic and sometimes even the only available welding method used for joining the aforesaid materials in production of various systems, heat exchangers and, in case of titanium alloys based on intermetallic compounds, turbine elements and space shuttle plating etc. This article presents the basic physical and chemical properties as well as the brazability of alloys based on intermetallic compounds. The work also describes the principle and mechanisms of diffusion-brazed joint formation as well as reveals the results of metallographic and strength tests involving diffusion-welded joints of TiAl48Cr3Nb2 casting alloy based on TiAl (γ phase with the use of sandwich-type layers of silver-based parent metal (grade B- Ag72Cu-780 (AG 401 and copper (grade CF032A. Structural examination was performed by means of light microscopy, scanning electron microscope (SEM and energy dispersion spectrometer (EDS. Furthermore, the article reveals the results of shear strength tests involving the aforementioned joints.

  10. Step brazing a multi-target TRAX

    International Nuclear Information System (INIS)

    Fabrication of a target holder for a multi-target transmission anode x-ray tube (TRAX) involved joining of five different materials. The TRAX will generate a nearly mono-energetic x-ray beam useful for instrument calibration and dosimetry studies. Each of three different targets will provide a different energy. The design will allow the experimenter to place a different target in front of the electron beam without breaking vacuum each time. The procedure is described for attaching three 12.7 mm (1/2 in.) diameter targets - made of tungsten, gold and uranium 238 (D-38) - to an OFHC copper support bar. The joining of the copper bar to a welded stainless steel bellows and flange is also described

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

    International Nuclear Information System (INIS)

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

  12. Development of high productivity pipeline girth welding

    International Nuclear Information System (INIS)

    The trend for increased oil and gas consumption implies a growth of long-distance pipeline installations. Welding is a critical factor in the installation of pipelines, both onshore and offshore, and the rate at which the pipeline can be laid is generally determined by the speed of welding. This has resulted in substantial developments in pipeline welding techniques. Arc welding is still the dominant process used in practice, and forge welding processes have had limited successful application to date, in spite of large investments in process development. Power beam processes have also been investigated in detail and the latest laser systems now show promise for practical application. In recent years the use of high strength steels has substantially reduced the cost of pipeline installation, with X70 and X80 being commonly used. This use of high strength pipeline produced by thermomechanical processing has also been researched. They must all meet three requirments, high productivity, satisfactory weld properties, and weld quality

  13. Bringing Pulsed Laser Welding into Production

    DEFF Research Database (Denmark)

    Olsen, Flemmming Ove

    1996-01-01

    production of hermetic weld seams produced on radiator thermostats applying pulsed laser welding. This application has now been running in several years. 2 laser systems are currently welding each serving two welding stations. Another case story is describing a high precision assembly technique of a product......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...

  14. Laser welding engineering

    International Nuclear Information System (INIS)

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

  15. 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…

  16. Heating coil welding technique for connection of large-diameter PE pipes using universally applicable, flexible taped joints; Heizwendelschweissverfahren fuer die Verbindung von PE-Grossrohren mittels universal anwendbarer, flexibler Wickelmuffen

    Energy Technology Data Exchange (ETDEWEB)

    Baudrit, Benjamin; Kraus, Eduard; Heidemeyer, Peter; Bastian, Martin [Sueddeutsche Kunststoff-Zentrum, Wuerzburg (Germany); Kern, Juergen; Neufeld, Wjatscheslaw [Frank und Krah Wickelrohr GmbH, Woelfersheim (Germany)

    2011-07-01

    This research project (Heating coil welding technique for connection of large-diameter PE pipes using universally applicable, flexible taped joints) was carried out by SKZ (Sueddeutsches Kunststoff-Zentrum) in close coopearation with Messrs. Frank and Krah Wickelrohr GmbH with the intention to develop a high-quality, economically efficient joining process for large-diameter pipes. The technique is based on the new technology of heating coil joints which permits the use of any desired joint geometries at acceptable cost. The new technique was validated for joints up to a diameter of 1,000 mm. With the welding parameters calculated in the project, even larger diameter joints are possible in theory.

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

    International Nuclear Information System (INIS)

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

  18. Welding robots

    OpenAIRE

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

    2003-01-01

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

  19. Effect of Welding Current on the Structure and Properties of Resistance Spot Welded Dissimilar (Austenitic Stainless Steel and Low Carbon Steel) Metal Joints

    Science.gov (United States)

    Shawon, M. R. A.; Gulshan, F.; Kurny, A. S. W.

    2015-04-01

    1.5 mm thick sheet metal coupons of austenitic stainless steel and plain low carbon steel were welded by resistance spot welding technique. The effects of welding current in the range 3-9 kA on the structure and mechanical properties of welded joint were investigated. The structure was studied by macroscopic, microscopic and scanning electron microscopy techniques. Mechanical properties were determined by tensile testing and microhardness measurements. Asymmetrical shape weld nugget was found to have formed in the welded joint which increased in size with an increase in welding current. The fusion zone showed cast structure with coarse columnar grain and dendritic with excess delta ferrite in austenitic matrix. Microhardness of the weld nugget was maximum because of martensite formation. An increase in welding current also increased tensile strength of the weld coupon. An attempt has also been made to relate the mode of fracture with the welding current.

  20. Effects of conventional welding and laser welding on the tensile strength, ultimate tensile strength and surface characteristics of two cobalt-chromium alloys: a comparative study.

    Science.gov (United States)

    Madhan Kumar, Seenivasan; Sethumadhava, Jayesh Raghavendra; Anand Kumar, Vaidyanathan; Manita, Grover

    2012-06-01

    The purpose of this study was to evaluate the efficacy of laser welding and conventional welding on the tensile strength and ultimate tensile strength of the cobalt-chromium alloy. Samples were prepared with two commercially available cobalt-chromium alloys (Wironium plus and Diadur alloy). The samples were sectioned and the broken fragments were joined using Conventional and Laser welding techniques. The welded joints were subjected to tensile and ultimate tensile strength testing; and scanning electron microscope to evaluate the surface characteristics at the welded site. Both on laser welding as well as on conventional welding technique, Diadur alloy samples showed lesser values when tested for tensile and ultimate tensile strength when compared to Wironium alloy samples. Under the scanning electron microscope, the laser welded joints show uniform welding and continuous molt pool all over the surface with less porosity than the conventionally welded joints. Laser welding is an advantageous method of connecting or repairing cast metal prosthetic frameworks. PMID:23858281

  1. 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.

  2. A new simulation model and its application in CO2 short-circuiting transfer welding

    Institute of Scientific and Technical Information of China (English)

    胡连海; 李桓; 李俊岳; 杨立军

    2002-01-01

    A new simulation model of CO2 short-circuiting transfer welding may be employed to develop a new pattern of welding machine and to predict welding process parameters to obtain the optimum welding technology properties. In this paper, a new simulating model is developed according to the AWP (adapting welding physics process) waveform control method. Good agreement is shown between the predicted and experimentally determined results. The model will make an important promotion in the development of CO2 arc welding technique.

  3. Evaluation of the Low Heat Input Process for Weld Repair of Nickel-Base Superalloys

    Science.gov (United States)

    Durocher, J.; Richards, N. L.

    2011-10-01

    The repair of turbine blades and vanes commonly involves gas tungsten arc welding or an equivalent process, but unfortunately these components are often susceptible to heat-affected zone (HAZ) cracking during the weld repair process. This is a major problem especially in cast alloys due to their coarse-grain size and where the (Al + Ti) contents is in excess of 3-4%; vacuum brazing is also used but mainly on low stress non-rotating components such as vanes. Micro-welding has the potential to deposit small amounts of filler at low heat input levels with minimum HAZ and thus is an attractive process for depositing a quality weld. As with conventional fusion processes, the filler alloy is deposited by the generation of a low power arc between a consumable electrode and the substrate. The low heat input of this process offers unique advantages over more common welding processes such as gas tungsten arc, plasma arc, laser, and electron beam welding. In this study, the low heat input characteristic of micro-welding has been used to simulate weld repair using Inconel (IN) (Inconel and IN are trademarks of INCO Alloys International) 625, Rene (Rene is a trademark of General Electric Company) 41, Nimonic (Nimonic is a trademark of INCO Alloys International) 105 and Inconel 738LC filler alloys, to a cast Inconel 738LC substrate. The effect of micro-welding process parameters on the deposition rate, coating quality, and substrate has been investigated.

  4. Interface characteristics and fracture behavior of brazed polycrystalline CBN grains using Cu-Sn-Ti alloy

    Energy Technology Data Exchange (ETDEWEB)

    Ding, Wen-Feng, E-mail: dingwf2000@vip.163.com [College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China); Xu, Jiu-Hua; Chen, Zhen-Zhen; Miao, Qing; Yang, Chang-Yong [College of Mechanical and Electrical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016 (China)

    2013-01-01

    Polycrystalline CBN grains were brazed onto AISI 1045 steel matrix using Cu-Sn-Ti brazing alloy. Brazing temperature was 880 Degree-Sign C, 900 Degree-Sign C, 920 Degree-Sign C respectively, and the holding time was 8 min. Interface characteristics, elemental distribution and fracture behavior were analyzed in detail by means of scanning electron microscopy, energy dispersive spectroscopy and testing machine for grain compressive strength. The maximum value of the mean compressive strength of brazed PCBN grains reached 879.3 MPa when the brazing temperature was 900 Degree-Sign C. The resultants layer composed of TiN, TiB{sub 2}, TiB and TiAl{sub 3} was formed at grain/alloy interface. Elemental distribution showed that Ti mainly concentrated within the interface zone. The intercrystalline fracture along the CBN/CBN particle boundary was the main fracture modes of brazed polycrystalline CBN grains.

  5. Dissimilar joint characteristics of SiC and WC-Co alloy by laser brazing

    Science.gov (United States)

    Nagatsuka, K.; Sechi, Y.; Nakata, K.

    2012-08-01

    SiC and WC-Co alloys were joined by laser brazing with an active braze metal. The braze metal based on eutectic Ag-Cu alloy with additional Ti as an active element ranging from 0 to 2.8 mass% was sandwiched by the SiC block and WC-Co alloy plate. The brazing was carried out by selective laser beam irradiation on the WC-Co alloy plate. The content of Ti in the braze metal was required to exceed 0.6 mass% in order to form a brazed joint with a measurable shear strength. The shear strength increased with increasing Ti content up to 2.3 mass%Ti and decreased with a higher content.

  6. Rapid Fabrication Techniques for Liquid Rocket Channel Wall Nozzles

    Science.gov (United States)

    Gradl, Paul R.

    2016-01-01

    The functions of a regeneratively-cooled nozzle are to (1) expand combustion gases to increase exhaust gas velocity while, (2) maintaining adequate wall temperatures to prevent structural failure, and (3) transfer heat from the hot gases to the coolant fluid to promote injector performance and stability. Regeneratively-cooled nozzles are grouped into two categories: tube-wall nozzles and channel wall nozzles. A channel wall nozzle is designed with an internal liner containing a series of integral coolant channels that are closed out with an external jacket. Manifolds are attached at each end of the nozzle to distribute coolant to and away from the channels. A variety of manufacturing techniques have been explored for channel wall nozzles, including state of the art laser-welded closeouts and pressure-assisted braze closeouts. This paper discusses techniques that NASA MSFC is evaluating for rapid fabrication of channel wall nozzles that address liner fabrication, slotting techniques and liner closeout techniques. Techniques being evaluated for liner fabrication include large-scale additive manufacturing of freeform-deposition structures to create the liner blanks. Abrasive water jet milling is being evaluated for cutting the complex coolant channel geometries. Techniques being considered for rapid closeout of the slotted liners include freeform deposition, explosive bonding and Cold Spray. Each of these techniques, development work and results are discussed in further detail in this paper.

  7. Effect of Heat Treatment on High Temperature Stress Rupture Strength of Brazing Seam for Nickel-base Superalloy

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    In order to enhance the high-temperature stress rupture strength of brazing seam by heat treatment, it was diffusion treated, then solution heat treated, and finally aging treated. The microstructure of brazing seam especially morphology of phase and boride was observed and the strength of brazing seam was measured in this process. The results show that heat treatment can enhance high-temperature stress rupture strength by improving the microstructure of brazing seam. The strength of brazing seam after solution heat treatment decreases in comparison with that only after diffusion treatment while aging treatment after solution heat treatment increases the strength of brazing seam.

  8. 铝钢异种材料电弧熔钎焊接技术的研究%Investigation on Arc Brazing Technology of Aluminum and Steel

    Institute of Scientific and Technical Information of China (English)

    尹兰礼; 雷永平; 林健; 王培中; 钟毅

    2011-01-01

    为了减轻车身重量,铝合金正被广泛的应用到汽车车身用中.而铝合金与汽车用钢板的连接问题是铝合金得以广泛应用的关键.本研究通过钨极氩弧焊和冷金属过渡焊两种电弧熔钎焊接方法实现铝合金与低碳钢的连接,研究了两种焊接方法的焊缝成型、接头拉剪强度以及金属间化合物的成分差异,并与传统的铆接接头进行比较.研究表明,电弧熔钎焊具有较高的接头拉剪强度和较小的接头重量.由于冷金属过渡焊的热输入量低,使得其焊缝成型相对较好,且其接头拉剪强度值已达到母材强度的85%.%Aluminum is being widely applied to automobile body to reduce the weight The key problem is connecting aluminum alloy to steel of car-body. In this paper, aluminum and steel are connected by Tungsten Inert Gas (TIG) arc brazing and Cold Metal Transfer (CMT) arc brazing. The weld formation of the two welding methods and component of intermetallic compounds (IMC) are investigated, and compared the joint's tensile-shear strength with traditional Self-piercing riveting. The results show that the joints made by arc brazing have higher tensile-shear strength and lighter weight. Due to the low welding heat input, the weld formation of CMT is better than that of TIG. And the tensile-shear strength of CMT joint has reached 85% of the base metal strength.

  9. Microstructural characteristics of WC-Co and tool steel brazed joint

    Energy Technology Data Exchange (ETDEWEB)

    Young-Sub, K.; Sook-Hwan, K. [Reliability Assessment Team, Research Institute of Industrial Science and Technology, Pohang (Korea)

    2001-07-01

    The current study used Ni base alloys, which reveals the excellent high temperature properties, as filler metals for brazing of WC-Co and tool steel to get the solid joint strength. The strength and the microstructures of brazed joints for different filler metals were examined. The optimum brazing condition and heat treatment condition were obtained through precipitation reaction and microstructural characteristics at the joints. (orig.)

  10. Nondestructive Ultrasonic Inspection of Friction Stir Welds

    Science.gov (United States)

    Tabatabaeipour, M.; Hettler, J.; Delrue, S.; Van Den Abeele, K.

    Friction Stir Welding (FSW) is a relatively new solid-state welding procedure developed at The Welding Institute (TWI-UK) and the technique is widely employed for welding aluminum alloys in various applications. In order to examine the quality of the welds and to detect a variety of welding flaws such as wormholes and root-flaws, it is required to develop a methodical inspection technique that can be used for the identification and localization of such defects. The most prevalent and risky defect in this type of welding is the barely visible root flaw with a length varying from 100-700 μm. Due to the extreme characteristics of the flaw, off-the-shelf ultrasonic weld inspection methods are not always able to readily detect this type of minute defect feature. Here, we propose a novel approach to characterize root flaws using an oblique incident ultrasonic C-scan backscattering analysis. The implementation consists of an immersion ultrasonic testing method in pulse echo (i.e. backscatter) mode with a 3.5 MHz transducer, and makes use of an empirical procedure to engender of a shear wave dominated excitation at the root surface, and to properly gate the received signal for root flaw examination. By scanning the surface above the welded component, a C-scan image displaying the backscatter response from the root surface of the nugget zone can be obtained which allows a simple interpretation of the root flaw status of the weld.

  11. Low vapor pressure braze alloys for thermionic energy converters

    Science.gov (United States)

    Bair, V. L.

    1976-01-01

    Preliminary results in the use of some low-vapor-pressure braze alloys are reported; these are binary alloys of refractory metals (Th, Zr, Hf, Ru, Nb, Ir, Mo, Ta, Os, Re, W) with vapor pressures below 0.1 nanotorr at 1500 K or 10 microtorr at 2000 K. The melting point minima or eutectics of the alloys range from 1510 K to above 3000 K. Melting points and surface wetting on a Ta base are given. Results are presented on brazing of Ir, LaB6, Nb, Re, W, and ZrO2 (with 22 wt % Zr) into a Ta base or a Nb-1% Zr base. The results are applicable in electrode screening programs for thermionic cesium diodes.

  12. An unconventional set-up for fluxless brazing of aluminium

    CERN Document Server

    Loos, Robert

    1999-01-01

    In order to successfully braze aluminium alloy assemblies without the use of oxide-removing fluxes, an evironment with very low contaminant level is mandatory. This is mostly achieved by using a vacuum furnace. Brazing under inert gas of sufficient purity is also possible. The method reported upon here makes use of a stainless steel bag which can enter a traditional air furnace. The bag is evacuated, giving a well distributed mechanical pressure on the parts to join. The intrinsic handicap of poor vacuum is compensated by regular inert gas flushing, even at high temperatures. The set-up works rather well, and the idea is believed to yield a valuable strategic and economic option, for the realization of special equipment as well as for prototyping work. We intend to use the principle for the CMS Preshower cooling screens.

  13. DSC Analysis of LT-3 Aluminum Alloy Vacuum Brazing

    Institute of Scientific and Technical Information of China (English)

    FENG Tao; WU Lu-hai; LOU Song-nian; LI Ya-jiang

    2005-01-01

    LT-3 aluminum alloy is a kind of two-side cladding aluminum special used in vacuum brazing. Differential Scanning Calorimeter (DSC) was used to measure the exothermic and endothermic reaction during the brazing process that the cortex metal and the base metal are melted and re-crystal. The analysis results inidicate that eutectic reaction is the main reaction in the melted cortex metal crystallization process. But the main reaction in the melted base metal crystallization process is the reaction that a-A1 segregated out. According to the experimental details, the critical work of nucleation is 3.82 × 1017J, the critical radius of nucleation is 8.69 × 1010 m, the volume of critical crystal nucleus is 2.75× 10-27 m3 and the per unit cell in critical crystal nucleus is 43.

  14. New hermetic sealing material for vacuum brazing of stainless steels

    Science.gov (United States)

    Hildebrandt, S.; Wiehl, G.; Silze, F.

    2016-03-01

    For vacuum brazing applications such as in vacuum interrupter industry Hermetic Sealing Materials (HSM) with low partial pressure are widely used. AgCu28 dominates the hermetic sealing market, as it has a very good wetting behavior on copper and metallized ceramics. Within recent decades wetting on stainless steel has become more and more important. However, today the silver content of HSMs is more in focus than in the past decades, because it has the biggest impact on the material prices. Umicore Technical Materials has developed a new copper based HSM, CuAg40Ga10. The wettability on stainless steel is significantly improved compared to AgCu28 and the total silver content is reduced by almost 44%. In this article the physical properties of the alloy and its brazed joints will be presented compared to AgCu28.

  15. Laser Brazing with Beam Scanning: Experimental and Simulative Analysis

    Science.gov (United States)

    Heitmanek, M.; Dobler, M.; Graudenz, M.; Perret, W.; Göbel, G.; Schmidt, M.; Beyer, E.

    Laser beam brazing with copper based filler wire is a widely established technology for joining zinc-coated steel plates in the body-shop. Successful applications are the divided tailgate or the zero-gap joint, which represents the joint between the side panel and the roof-top of the body-in-white. These joints are in direct view to the customer, and therefore have to fulfil highest optical quality requirements. For this reason a stable and efficient laser brazing process is essential. In this paper the current results on quality improvement due to one dimensional laser beam deflections in feed direction are presented. Additionally to the experimental results a transient three-dimensional simulation model for the laser beam brazing process is taken into account. With this model the influence of scanning parameters on filler wire temperature and melt pool characteristics is analyzed. The theoretical predictions are in good accordance with the experimental results. They show that the beam scanning approach is a very promising method to increase process stability and seam quality.

  16. Differences between Laser and Arc Welding of HSS Steels

    Science.gov (United States)

    Němeček, Stanislav; Mužík, Tomáš; Míšek, Michal

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

  17. Pulsed Magnetic Welding for Advanced Core and Cladding Steel

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-12-19

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

  18. Sensor controlled robotic welding for nuclear power plant operations

    International Nuclear Information System (INIS)

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

  19. Controlling phase formation during aluminium/steel Nd:YAG laser brazing

    Directory of Open Access Journals (Sweden)

    Rodriguez, L.

    2006-12-01

    Full Text Available The reduction of fuel consumption of internal combustion motors, imposed by the new anti-pollution and energy saving laws may be attained by reducing the weight of vehicles, introducing, for example, aluminium sections into the main steel car-body. Laser brazing is a process which can be used to perform such a junction. The main problem of welding this kind of materials combination with conventional processes is the potential formation of inter-metallic phases, which reduces the good performance of the joint. Laser brazing allows a very good control of the thermal development of the joint, with a limited precipitation of these brittle phases. This paper presents the results of a feasibility study made with ZnAl-30 as filler metal. The study shows that the type of configuration used for the assembly has a particular influence on the formation of brittle phases and consequently on the mechanical performance of the joint.

    La reducción en el consumo de combustibles fósiles y las emergentes leyes mundiales anti-contaminación, obligan a prever una reducción en el peso de los vehículos de transporte. Esta condición se puede cumplir por ejemplo, introduciendo componentes de Aluminio en el cuerpo de la carrocería principal de acero de los mencionados vehículos. El principal problema que se presenta al realizar este tipo de ensamblaje es la formación de fases íntermetálicas frágiles que pueden comprometer el buen desenvolvimiento de la unión. La soldadura con rayo láser permite un buen control de calor aportado y una formación muy limitada de este tipo de fases. Este trabajo presenta los resultados preliminares de los estudios realizados en uniones soldadas con ZnAl-30 como material de aportación. El estudio muestra que el tipo de configuración utilizada para realizar la soldadura tiene una influencia importante sobre la posibilidad de formación de estas fases ínter-metálicas.

  20. Friction Pull Plug Welding in Aluminum Alloys

    Science.gov (United States)

    Brooke, Shane A.; Bradford, Vann

    2012-01-01

    NASA's Marshall Space Flight Center (MSFC) has recently invested much time and effort into the process development of Friction Pull Plug Welding (FPPW). FPPW, is a welding process similar to Friction Push Plug Welding in that, there is a small rotating part (plug) being spun and simultaneously pulled (forged) into a larger part. These two processes differ, in that push plug welding requires an internal reaction support, while pull plug welding reacts to the load externally. FPPW was originally conceived as a post proof repair technique for the Space Shuttle fs External Tank. FPPW was easily selected as the primary weld process used to close out the termination hole on the Constellation Program's ARES I Upper Stage circumferential Self-Reacting Friction Stir Welds (SR-FSW). The versatility of FPPW allows it to also be used as a repair technique for both SR-FSW and Conventional Friction Stir Welds. To date, all MSFC led development has been concentrated on aluminum alloys (2195, 2219, and 2014). Much work has been done to fully understand and characterize the process's limitations. A heavy emphasis has been spent on plug design, to match the various weldland thicknesses and alloy combinations. This presentation will summarize these development efforts including weld parameter development, process control, parameter sensitivity studies, plug repair techniques, material properties including tensile, fracture and failure analysis.

  1. Research on CMT welding of nickel-based alloy with stainless steel

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Cold Metal Transfer (CMT) welding technique is a new welding technique introduced by Fronius company. CMT welding of nickel-based alloy with stainless steel was carried out using CuSi3 filler wire in this paper. Effects of welding parameters, including welding current, welding speed, etc, on weld surface appearance were tested. Microstructure and mechanical properties of CMT weld were studied. The results show that the thickness of interface reaction layer of the nickel-based alloy is 14.3μm, which is only 4.33% of base material. The weld is made up of two phases,α-copper and iron-based solid solution. Rupture occurs initially at the welded seam near the edge of stainless steel in shear test. The maximum shear strength of the CuSi3 welded joint is 184.9MPa.

  2. Research status and development tendency of welding technology of AZ31B magnesium alloy%AZ31B镁合金焊接技术研究现状及发展方向

    Institute of Scientific and Technical Information of China (English)

    刘奋军; 王憨鹰

    2013-01-01

    Welding characteristics of magnesium alloy are analyzed,and welding processes of AZ31B magnesium alloy are introduced,including laser welding,brazing,diffusion welding,friction stir welding,TIG,electron beam welding and so on. The future directions of welding technology of AZ31B magnesium alloy are pointed out.%分析镁合金的焊接特点,综述了近年来AZ31B镁合金的焊接方法,包括激光焊、钎焊、扩散焊、搅拌摩擦焊、TIG焊、电子束焊等,展望了AZ31B镁合金的焊接研究方向。

  3. Welding Curtains

    Science.gov (United States)

    1984-01-01

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

  4. EFFECT OF CARBON MIGRATION ON CREEP PROPERTIES OF Cr5Mo DISSIMILAR WELDED JOINTS WITH Ni-BASED AND AUSTENITIC WELD METAL

    Institute of Scientific and Technical Information of China (English)

    J.M. Gong; Y. Jiang; S.T. Tu

    2004-01-01

    In this paper, the effect of carbon migration on creep properties of Cr5Mo dissimilar welded joints with Ni-based (Inconel 182) and Cr23Ni13 (A302) austenitic weld metal was investigated. Carbon migration near the weld metal/ferritic steel interface of Cr5Mo dissimilar welded joints was analyzed by aging method. Local creep deformations of the dissimilar welded joints were measured by a long-term local creep deformation measuring technique. The creep rupture testing was performed for Cr5Mo dissimilar welded joints with Inconel 182 and A302 weld metal. The research results show that the maximum creep strain rate occurs in the decarburized zone located on heat affect zone (HAZ) of Cr5Mo ferritic steel. The creep rupture life of Cr5Mo dissimilar welded joints with A302 weld metal decreases due to carbon migration and is about 50% of that welded with Inconel 182 weld metal.

  5. Welding in space and the construction of space vehicles by welding; Proceedings of the Conference, New Carrollton, MD, Sept. 24-26, 1991

    Science.gov (United States)

    The present conference discusses such topics in spacecraft welding as the NASA Long Duration Exposure Facility's evidence on material properties degradation, EVA/telerobotic construction techniques, welding of the superfluid helium on-orbit transfer flight demonstration tanks and hardware, electron-beam welding of aerospace vehicles, variable-polarity plasma arc keyhole welding of Al, aircraft experiments of low-gravity fusion welding, flash-butt welding of Al alloys, and a computer-aided handbook for space welding fabrication. Also discussed are the welded nozzle extension for Ariane launch vehicles, the existence of on-orbit cold-welding, structural materials performance in long-term space service, high-strength lightweight alloys, steels, and heat-resistant alloys for aerospace welded structures, the NASA-Goddard satellite repair program, and the uses of explosion welding and cutting in aerospace engineering.

  6. Use of laser cutting and welding in nuclear industry

    International Nuclear Information System (INIS)

    General data on peculiarities of laser welding and cutting procedure are reviewed. Specific examples of laser application for fuel assembly production and reprocessing, for welding of heat exchangers and pipelines etc are considered to show the advantages of the technique. A series of patents, dealing with laser cutting and welding is being discussed

  7. A Computer Aided System for Simulating Weld Metal Solidification Crack

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A computer-aided system for simulating weld solidification crack has been developed by which a welding engineer can carry out the welding solidification crack simulation on the basis of a commercial finite element analysis software package. Its main functions include calculating the heat generations of the moving arc, mesh generation, calculating stress-strain distributions with element rebirth technique.

  8. A study on brazing of Glidcop® to OFE Cu for application in Photon Absorbers of Indus-2

    International Nuclear Information System (INIS)

    The paper describes an experimental study aimed at standardizing brazing procedure for joining Glidcop to OFE Cu for its application in upgraded photon absorbers of 2.5 GeV synchrotron radiation source, Indus-2. Two different brazing routes, involving brazing with silver base (BVAg-8) and gold base (50Au/50Cu) alloys, were studied to join Glidcop to OFE Cu. Brazing with both alloys yielded helium leak tight and bakeable joints with acceptable shear strengths.

  9. Friction Stir.Welding is an advance metal joining process: A Review

    OpenAIRE

    Umasankar Das,; Dr. Vijay Toppo

    2015-01-01

    The friction stir welding is recently developed solid state welding process which overcome the problem associated with fusion welding technology. The properties achieved by friction stir welding is better than that achieve by fusion welding technique It has been invented as a solid-state joining technique and initially applied to aluminum alloys. FSW is used to replace rivets joints in the aeronautical industry. Recently the aircraft and military industries widely have been using ...

  10. 多元平行流式冷凝器炉中钎焊工艺研究%Study on Brazing Process for Condenser in Controlled Atmosphere Brazing Furnace

    Institute of Scientific and Technical Information of China (English)

    郭艳; 凌泽民; 李金阁

    2011-01-01

    The optimum technological parameters of brazing condenser in controlled atmosphere brazing(CAB) furnace were obtained by simulating 3-D temperature distribution of micro-joint between fin and flat tube of the condenser using ANSYS software. The process experiment, temperature measurement and properties testing were carried out. The results show that the real thermal cycle curve fits well with the initial simulation one. The morphology of the welded joint has no defects and the microstructure is dense and mainly a(Al)+Al-Si. The leaking has no slightly leaking. It can be obtained that it is a meaningful method to put FEM employ into the process design.%采用ANSYS软件,通过对温度场的模拟,确定了较佳的工艺参数,并进行了工艺实验、温度检测及相关性能测试.温度检测结果表明,模拟曲线与实测曲线吻合较好,说明模拟的温度场是正确的.通过对钎焊接头显微组织分析表明,接头无缺陷,组织致密,显微组织主要以a(Al)+Al-Si共晶组织为主;相关性能测试表明,接头无微漏,达到了使用要求.说明采用有限元软件进行工艺指导是可行的.

  11. BASIC THEORY AND APPLICATIONS OF WELDING ARC SPECTRAL INFORMATION

    Institute of Scientific and Technical Information of China (English)

    LI Junyue; XUE Haitao; LI Huan; SONG Yonglun

    2007-01-01

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

  12. 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.

  13. 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. PMID:25322246

  14. Pearson's Functions to Describe FSW Weld Geometry

    International Nuclear Information System (INIS)

    Friction stir welding (FSW) is a relatively new joining technique particularly for aluminium alloys that are difficult to fusion weld. In this study, the geometry of the weld has been investigated and modelled using Pearson's functions. It has been demonstrated that the Pearson's parameters (mean, standard deviation, skewness, kurtosis and geometric constant) can be used to characterize the weld geometry and the tensile strength of the weld assembly. Pearson's parameters and process parameters are strongly correlated allowing to define a control process procedure for FSW assemblies which make radiographic or ultrasonic controls unnecessary. Finally, an optimisation using a Generalized Gradient Method allows to determine the geometry of the weld which maximises the assembly tensile strength.

  15. Knowledge based process development of bobbin tool friction stir welding

    OpenAIRE

    Hilgert, Jakob

    2012-01-01

    Over the last twenty years Friction Stir Welding (FSW) has proven to be a very promising new joining technique. Especially high strength aluminium alloys can be welded with large advantages as compared to conventional fusion welding processes. For some joint configurations and desired applications bobbin tool welding is a process variant that can circumvent limitations arising from the high process forces in conventional tool FSW. As bobbin tools are highly mechanically loaded, in-depth under...

  16. Digital Laser Welding System for Automobile Side Panel

    OpenAIRE

    Park, Hong-Seok; Choi, Hung-Won

    2010-01-01

    The laser as economical and flexible tool has established a solid ground in industrial manufacturing area. Specially at welding BIW (Body In White) in automobile industry, the importance of it has been increased due to the technological characteristics such as high process speed, slim seam and good capability of automation and so on. For application of laser welding technique, welding principle and influential factors were investigated based on the analysis of laser welding processes. With th...

  17. Improving Fatigue Performance of AHSS Welds

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-03-01

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

  18. Numerical modelling of steel arc welding

    International Nuclear Information System (INIS)

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

  19. 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.

  20. Improving fatigue performance of rail thermite welds

    Science.gov (United States)

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

    2010-06-01

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

  1. Interfacial microstructure and performance of brazed diamond grits with Ni-Cr-P alloy

    International Nuclear Information System (INIS)

    The reaction mechanism of the interface among diamond, commercial Ni-Cr-P alloy and steel substrate has been studied by optical microscopy, scanning electron microscope, X-ray diffraction and Raman spectroscopy. The reaction layers formed among diamond, brazing alloy and steel substrate produced good wettability of diamond grits for achieving better quality tools. The reaction layer between diamond and brazing alloy comprised a reaction layer of brazing alloy and a reaction layer of diamond. Cr7C3 and Cr3C2 formed in the reaction layer of brazing alloy was the main reason for improving the bonding strength of Ni-Cr alloy to the diamond grits. A reaction layer of diamond may be a graphitization layer formed on the surface of diamond under high temperature brazing. The reaction layer of brazing alloy and steel substrate was the co-diffusion of Ni, Cr and Fe between the brazing alloy and the steel substrate. The life and sharpness of brazed diamond boring drill bits fabricated in this study were superior to the electroplated one in the market owing to its high protrusion and bonding strength.

  2. Research on overall assembling and welding process of steel box girder tuyere blocks of Taizhou Bridge

    Institute of Scientific and Technical Information of China (English)

    Yan Shiguang; Li Hongtao; Wang Chao

    2012-01-01

    This article presents in detail the assembling and welding process technique of the steel box girder tuyere blocks of Taizhou Bridge. The application of this process technique effectively solves the problem of welding stress release in tuyere block assembling and welding without increasing the number of turns of the blocks and overhead welding, thus avoiding possible structural deformation due to excessive accumulation of internal welding stress, greatly reducing the repeated deformation and correction work during assembling and welding, and ensuring the weld seam quality and overall dimensions of tuvere blocks of Taizhou Bridze.

  3. Study of the electron beam welding of tubes to exchanger plates using a portable gun

    International Nuclear Information System (INIS)

    The purpose of the study, was to develop equipments and techniques allowing on the one hand, electron beam welding and, on the other hand, inspection of welds joining tubes to exchanger plates. Electron beam welding makes it possible to obtain very high penetration bead width ratios, very varied and reproducible thermal cycles, fast operating rates, welding on vertical walls with no difficulty

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

    Directory of Open Access Journals (Sweden)

    Koray Yurtisik

    2013-09-01

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

  5. Development of brazing foils to join monocrystalline tungsten alloys with ODS-EUROFER steel

    Energy Technology Data Exchange (ETDEWEB)

    Kalin, B.A. [Moscow Engineering Physics Institute (State University), 31 Kashirskoye Sh., Moscow 115409 (Russian Federation)]. E-mail: BAKalin@mephi.ru; Fedotov, V.T. [Moscow Engineering Physics Institute (State University), 31 Kashirskoye Sh., Moscow 115409 (Russian Federation); Sevrjukov, O.N. [Moscow Engineering Physics Institute (State University), 31 Kashirskoye Sh., Moscow 115409 (Russian Federation); Kalashnikov, A.N. [Moscow Engineering Physics Institute (State University), 31 Kashirskoye Sh., Moscow 115409 (Russian Federation); Suchkov, A.N. [Moscow Engineering Physics Institute (State University), 31 Kashirskoye Sh., Moscow 115409 (Russian Federation); Moeslang, A. [Forschungszentrum Karlsruhe, Institut fuer Materialforschung I, 76021 Karlsruhe (Germany); Rohde, M. [Forschungszentrum Karlsruhe, Institut fuer Materialforschung I, 76021 Karlsruhe (Germany)

    2007-08-01

    Results on rapidly solidified filler metals for brazing W with W and monocrystalline W with EUROFER steel (FS) are presented. Rapidly quenched powder-type filler metals based on Ti{sub bal}-V-Cr-Be were developed to braze polycrystalline W with monocrystalline W. In addition, Fe{sub bal}-Ta-Ge-Si-B-Pd alloys were developed to braze monocrystalline W with FS for helium gas cooled divertors and plasma-facing components. The W to FS brazed joints were fabricated under vacuum at 1150 {sup o}C, using a Ta spacer of 0.1 mm in thickness to account for the different thermal expansions. The monocrystalline tungsten as well as the related brazed joints withstood 30 cycles between 750 {sup o}C/20 min and air cooling/3-5 min.

  6. Development of dissimilar welding technique between PNC-FMS wrapper tube and SUS316 steel. 1. Investigation of δ ferrite formation and evaluation of Charpy impact property

    International Nuclear Information System (INIS)

    Ferritic/Martensitic steel (PNC-FMS) with superior resistance to swelling is being developed as wrapper tube for the long-life core of large-scale fast breeder reactor. If the δ ferrite phase would be formed at heat affected zone (HAZ) in welding between PNC-FMS wrapper tube and SUS316 steel, and thus toughness degradation would be suspected due to δ ferrite formation. In this study, the formation of the δ ferrite in applying TIG welding and EB welding are investigated using base metal of 3 types, which are Nieq max./Creq min., Nieq min./Creq max. and the center of chemical composition in the specification. The effect of the amount of the δ ferrite formation and characteristics of toughness change with thermal aging were evaluated. The results are summarized as follows. 1. The δ ferrite generation can be suppressed in the combination of welding process and chemical composition. (1) In case of specification center, the δ ferrite formation can be suppressed about 1% by EB welding. (2) In case of Nieq max./Creq min. in the specification, the δ ferrite formation can be perfectly suppressed even in TIG welding or EB welding. 2. The relationship between δ ferrite content and Charpy impact value was investigated using 3 types of chemical composition in the specification. (1) Ductile Brittle Transition Temperature (DBTT) increased, when δ ferrite content increases. (2) DBTT shift by aging is within about 23degC. (3) DBTT is influenced by grain size and it is lower as the fine grain (grain no.11). (4) Upper Shelf Energy (USE) is not dependent on the δ ferrite content. (author)

  7. Novel characterization of welding fumes

    International Nuclear Information System (INIS)

    Complete text of publication follows. The lung deposition of welding fume comprised of a large number of primary nanoparticles, occurs predominantly in the alveolar region. The particle size distribution of welding fumes is an important factor determining the bioaccessibility of metal components and the hazard potential of pro-inflammatory effects driven largely by soluble and insoluble transition metals. Several techniques are frequently used for determining the particle size distribution of different welding fumes. A scanning mobility particle sizer (SMPS) offers the opportunity of temporal particle-size distribution measurements and to follow the changes in particle number concentration, a transmission electron microscope (TEM) is capable of visualizing the individual particle morphology and measuring the particle size of primary particles. Are the results obtained with these two techniques comparable? To answer this question welding fumes were generated by different welding methods and examined by a SMPS in the range of 10 to 487 nanometers. The SMPS instrument measures the size distribution of fine particles by separating particles based on electrical-mobility. Particles of a selected size are detected optically, using a detection technology in which small particle visibility is enhanced by growing the particles in a condensing butyl alcohol vapour. Samples were collected on TEM grids made of nickel, copper and silicon for primary particle characterization by TEM. Particle size distributions with both analytical techniques were determined. The most obvious features of the TEM analysis were that the primary welding fume particles had a tendency to form chainlike agglomerates in case of all welding, and almost no individual primary particles were found. It is quite unclear how these agglomerates are detected by the SMPS. An important finding of the chemical analysis of the particles by TEM was that the larger particles contained cores of more volatile components

  8. End plug welding of FBTR fuel element by Nd-YAG CW laser

    International Nuclear Information System (INIS)

    Currently thin walled SS-316 FBTR fuel element is closed at both ends with SS solid plug using TIG welding at Radiometallurgy Division, Bhabha Atomic Research Centre. This welding is involved with material of non uniform thickness. The tube is thinner whereas solid plug is thicker material. Precise control of welding parameters and positioning of torch is necessary during welding to get satisfactory penetration without any major defect. In order to meet the objective of achieving good quality weld heat input during welding has to be kept minimal. Of late in Radiometallurgy Division, Bhabha Atomic Research Centre Nd-YAG CW laser welding has been introduced for end plug welding of the fuel element. Necessary experiments have been done to evaluate the performance of laser welding process for the welding of FBTR fuel elements. Laser welding of fuel element has been done at different power level and speeds. The depth of penetration, fusion zone shape, overall weld profile and weld bead thickness have been evaluated. The amount of liquid metal formed during welding has been calculated theoretically by fitting the overall weld profile in mathematical function. The weld profile area has been estimated by image analysis technique. From these data, the heat absorption by the weld pool have been calculated and thermal efficiency has been estimated. Attempt has been made to optimize laser welding parameters. (author)

  9. Microstructure characterization of Friction Stir Spot Welded TRIP steel

    DEFF Research Database (Denmark)

    Lomholt, Trine Colding; Adachi, Yoshitaka; Peterson, Jeremy;

    2012-01-01

    Transformation Induced Plasticity (TRIP) steels have not yet been successfully joined by any welding technique. It is desirable to search for a suitable welding technique that opens up for full usability of TRIP steels. In this study, the potential of joining TRIP steel with Friction Stir Spot...... Welding (FSSW) is investigated. The aim of the study is to investigate whether acceptable welds can be produced, and additionally, to obtain an understanding of the microstructural changes during welding. The microstructure was investigated with a combination of microscopical techniques with the aim...... of identifying the transformations occurring during welding. Reflected light microscopy, scanning electron microscopy, and electron backscatter diffraction were among the methods applied for detailed investigations. The microstructure adjacent to the welds can generally be subdivided in two thermo...

  10. 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...

  11. Laser Welding in Electronic Packaging

    Science.gov (United States)

    2000-01-01

    The laser has proven its worth in numerous high reliability electronic packaging applications ranging from medical to missile electronics. In particular, the pulsed YAG laser is an extremely flexible and versatile too] capable of hermetically sealing microelectronics packages containing sensitive components without damaging them. This paper presents an overview of details that must be considered for successful use of laser welding when addressing electronic package sealing. These include; metallurgical considerations such as alloy and plating selection, weld joint configuration, design of optics, use of protective gases and control of thermal distortions. The primary limitations on use of laser welding electronic for packaging applications are economic ones. The laser itself is a relatively costly device when compared to competing welding equipment. Further, the cost of consumables and repairs can be significant. These facts have relegated laser welding to use only where it presents a distinct quality or reliability advantages over other techniques of electronic package sealing. Because of the unique noncontact and low heat inputs characteristics of laser welding, it is an ideal candidate for sealing electronic packages containing MEMS devices (microelectromechanical systems). This paper addresses how the unique advantages of the pulsed YAG laser can be used to simplify MEMS packaging and deliver a product of improved quality.

  12. 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.

  13. Laser based spot weld characterization

    Science.gov (United States)

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

    2016-02-01

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

  14. Double global optimum genetic algorithm-particle swarm optimization-based welding robot path planning

    Science.gov (United States)

    Wang, Xuewu; Shi, Yingpan; Ding, Dongyan; Gu, Xingsheng

    2016-02-01

    Spot-welding robots have a wide range of applications in manufacturing industries. There are usually many weld joints in a welding task, and a reasonable welding path to traverse these weld joints has a significant impact on welding efficiency. Traditional manual path planning techniques can handle a few weld joints effectively, but when the number of weld joints is large, it is difficult to obtain the optimal path. The traditional manual path planning method is also time consuming and inefficient, and cannot guarantee optimality. Double global optimum genetic algorithm-particle swarm optimization (GA-PSO) based on the GA and PSO algorithms is proposed to solve the welding robot path planning problem, where the shortest collision-free paths are used as the criteria to optimize the welding path. Besides algorithm effectiveness analysis and verification, the simulation results indicate that the algorithm has strong searching ability and practicality, and is suitable for welding robot path planning.

  15. Polyethylene welding by pulsed visible laser irradiation

    International Nuclear Information System (INIS)

    Laser welding of plastics is a relatively new process that induces locally a fast polymer heating. For most applications, the process involves directing a pulsed beam of visible light at the weld joint by going through one of the two parts. This is commonly referred to as 'through transmission visible laser welding'. In this technique, the monochromatic visible light source uses a power ns pulsed laser in order to irradiate the joint through one part and the light is absorbed in the vicinity of the other part. In order to evaluate the mechanical resistance of the welded joint, mass quadrupole spectrometry, surface profilometry, microscopy techniques and mechanical shear tests were employed. The welding effect was investigated as a function of the laser irradiation time, nature of the polyethylene materials and temperature.

  16. Ultrasonic testing of the depth of penetration of electron beam welds on heat exchanger tubes to tube plate assemblies

    International Nuclear Information System (INIS)

    A focused beam ultrasonic testing method is described, which controls weld penetration and more precisely welded zone depth. This technique has been applied to the control of electron beam welds of tube to plate assemblies on heat exchangers; electron beam welding, interesting from economical and technical points of view, induces irregularities in weld penetration. Used as a quality control method, it allows to precisely record some welding parameters (penetration depth, compactness defects, root shape...)

  17. Design strategy of intelligent CAD for welding positioner scheme design

    Institute of Scientific and Technical Information of China (English)

    林三宝; 杨春利; 吴林; 黎明

    2002-01-01

    Traditional CAD technique does not support the design processes such as function definition, conceptual design and preliminary design, which are most creative and play significant roles on the design quality. Because scheme design has close relationship with product structure, performance and technology cost, it is important for applying the intelligent CAD of scheme design to improve the quality and competitive level of the product. The definition and function of welding positioner are discussed in this paper. The new definition of welding positioner extends the research scope of welding positioner to welding fixture and welding positioning motion mechanism. The design process of welding fixture and positioning motion system is described, and the cased-based and knowledge-based design strategy of welding positioner scheme design intelligent CAD is then put forward, which lays foundation for developing proto-type system of welding positioner scheme design.

  18. Fatigue resistance of titanium laser and hybrid welded joints

    International Nuclear Information System (INIS)

    This paper presents a detailed study on fatigue strength of welded joints made of two titanium alloys, grade 2 and grade 5, and welded by laser or hybrid process. Fatigue strength curves obtained for each alloy and each welding technique are compared in terms of safety factors with fatigue design curves of welded joints provided by standards. Material and welding process effects on fatigue strength are discussed; the influence of the weld seam geometry is assessed by evaluating the fatigue strength reduction factor. This parameter is computed by using the Volumetric Method of the Notch Fracture Mechanics and defined as the ratio of the effective stress and the gross stress. Effective stress is defined on the weld toe stress distribution by the minimum of relative stress gradient method. Distribution of opening stress at weld toe is analysed also with the finite element analysis.

  19. Welding of the A1 reactor pressure vessel

    International Nuclear Information System (INIS)

    As concerns welding, the A-1 reactor pressure vessel represents a geometrically complex unit containing 1492 welded joints. The length of welded sections varies between 10 and 620 mm. At an operating temperature of 120 degC and a pressure of 650 N/cm2 the welded joints in the reactor core are exposed to an integral dose of 3x1018 n/cm2. The chemical composition is shown for pressure vessel steel as specified by CSN 413090.9 modified by Ni, Ti and Al additions, and for the welding electrodes used. The requirements are also shown for the mechanical properties of the base and the weld metals. The technique and conditions of welding are described. No defects were found in ultrasonic testing of welded joints. (J.B.)

  20. Seam Tracking Technology for Hyperbaric Underwater Welding

    Institute of Scientific and Technical Information of China (English)

    JIAO Xiangdong; YANG Yongyong; ZHOU Canfeng

    2009-01-01

    Automatic weld seam tracking technology to be used in hyperbaric underwater damaged pipeline repair welding is much more important, because of poor bevel preparation and severe working condition. A weld seam tracking system based on digital signal processing(DSP) passive light weld image processing technology has been established. A convenient charge coupled device(CCD) camera system was used in the high pressure environment with the help of an aperture and focus altering mechanism to guarantee overall image visibility in the scope of pressure below 0.7 MPa. The system can be used in the hyperbaric environment to pick up the real welding image of both the welding arc and the welding pool. The newly developed DSP technology was adopted to achieve the goal of system real time characteristics. An effective weld groove edge recognition technique including narrow interesting window opening, middle value wave filtering, Sobel operator weld edge detecting and edge searching in a defined narrow area was proposed to remove the guide error and system accuracy was ensured. The results of tracking simulation and real tracking application with arc striking have proved the validity and the accuracy of the mentioned system and the image processing method.

  1. Numerical simulation of friction stir welding

    Directory of Open Access Journals (Sweden)

    Mijajlović Miroslav

    2014-01-01

    Full Text Available Friction stir welding is a solid-state welding technique that utilizes thermo-mechanical influence of the rotating welding tool on parent material resulting with monolith joint-weld. On the contact of welding tool and parent material, significant stirring and deformation of parent material appears, and during this process mechanical energy is partially transformed into heat. The paper describes the software for the numerical simulation of friction stir welding developed at Mechanical Engineering Faculty, University of Nis. Numerical solution for estimation of welding plates temperature is estimated using finite difference method-explicit scheme with adaptive grid, considering influence of temperature on material's conductivity, contact conditions between welding tool and parent material, material flow around welding tool etc. The calculated results are in good agreement with the experimental results. [Projekat Ministarstva nauke Republike Srbije, br. TR35034: The research of modern non-conventional technologies application in manufacturing companies with the aim of increase efficiency of use, product quality, reduce of costs and save energy and materials

  2. Laser beam welding and friction stir welding of 6013-T6 aluminium alloy sheet

    International Nuclear Information System (INIS)

    Butt welds of 1.6 mm thick 6013-T6 sheet were produced using laser beam welding and friction stir welding processes. Employing the former joining technique, filler powders of the alloys Al-5%Mg and Al-12%Si were used. Microstructure, hardness profiles, tensile properties and the corrosion behaviour of the welds in the as-welded condition were investigated. The hardness in the weld zone was lower compared to that of the base material in the peak-aged temper. Hardness minima were measured in the fusion zone and in the thermomechanically affected zone for laser beam welded and friction stir welded joints, respectively. Metallographic and fractographic examinations revealed pores in the fusion zone of the laser beam welds. Porosity was higher in welds made using the filler alloy Al-5%Mg than using the filler metal Al-12%Si. Transmission electron microscopy indicated that the β'' (Mg2Si) hardening precipitates were dissolved in the weld zone due to the heat input of the joining processes. Joint efficiencies achieved for laser beam welds depended upon the filler powders, being about 60 and 80% using the alloys Al-5%Mg and Al-12%Si, respectively. Strength of the friction stir weld approached over 80% of the ultimate tensile strength of the 6013-T6 base material. Fracture occurred in the region of hardness minima unless defects in the weld zone led to premature failure. The heat input during welding did not cause a degradation of the corrosion behaviour of the welds, as found in continuous immersion tests in an aqueous chloride-peroxide solution. In contrast to the 6013-T6 parent material, the weld zone was not sensitive to intergranular corrosion. Alternate immersion tests in 3.5% NaCl solution indicated high stress corrosion cracking resistance of the joints. For laser beam welded sheet, the weld zone of alternately immersed specimens suffered severe degradation by pitting and intergranular corrosion, which may be associated with galvanic coupling of filler metal and

  3. Advanced Laser Transmission Welding Strategies for Fibre Reinforced Thermoplastics

    Science.gov (United States)

    Wippo, V.; Jaeschke, P.; Brueggmann, M.; Suttmann, O.; Overmeyer, L.

    Laser transmission welding can be used to join endless fibre reinforced thermoplastics. The welding temperature is affected by the heat conduction along carbon fibresand depends on the local orientation of the fibres in the weld seam and the laser welding technique itself. In these investigations the heat development during the welding with quasi-static temperature fields, which is a combination of two laser welding techniques, is evaluated and compared to welding with a homogenized intensity distribution. In order to optimize the temperature distribution over the weld seam width for both linear and curved weld seams, different scanning structures have beenadapted. The experiments were conducted with a diode laser emitting at a wavelength of 940 nm and the process was monitored by aninfrared camera. The used thermoplastics consist of laminates based on unidirectional carbon fibre reinforced polyphenylenesulfide. With the developed scanning structures, a near-homogeneous temperature distribution was generated over the width of the weld seam for curved weld seams, which is not possible by welding with a homogenized laser radiation intensity distribution.

  4. Optical monitoring of laser-generated plasma during laser welding

    Science.gov (United States)

    Connolly, John O.; Beirne, Gareth J.; O'Connor, Gerard M.; Glynn, Thomas J.; Conneely, Alan J.

    2000-03-01

    Process monitoring is a vital part of industrial laser applications that enables intelligent control of processes by observing acoustic, optical, thermal and other emissions. By monitoring these emission during laser processing, it is possible to ascertain characteristics that help diagnose features of the laser processed material and hence to optimize the technique. An experimental set up of observing plasmas during laser spot welding is described here. A pulsed Nd:YAG laser was used to spot-weld a variety of materials of different thickness, the plasmas generated during welding were monitored by a number of techniques, and the data obtained was used to characterize the welds. In the study photodiodes were set at different angles and observed the intensity and generation of the plasmas during the laser spot-welding process thereby giving a weld 'signature.' A portable spectrometer was used off-axis to obtain spectra of the emissions from the plasmas. Post process analysis was performed on the materials by mechanical polishing and chemical etching and observations of weld penetration depth and weld quality were correlated with the data collected on the plasmas. Different cover gases were also used during laser welding and the results of the effects of the various gases on the plasma are shown. The results indicate the relationship between laser weld generated plasma characteristics and weld features such as penetration depth. A direct correlation between the intensities of the photodiode and portable spectrometer signals was observed with weld penetration depth.

  5. Mg/Cu异种材料共晶反应钎焊连接研究%Dissimilar Metals Between Copper and Magnesium Alloy in Eutectic Contacting Reaction Brazing

    Institute of Scientific and Technical Information of China (English)

    王怀建; 袁苗达; 白莉

    2012-01-01

    Magnesium alloy (AZ31B) and Copper (T2) were bonded by eutectic contacting reaction brazing. The microstructural features and mechanical properties of the welded joint was studied by scanning electron microscopy (SEM), energy dispersive spectrometer (EDS). The results show that when the welding process is at 500 °C for 5 min, under the pressure of 2MPa, the tensile strength of the welded joint reaches 42MPa.%采用共晶钎焊工艺对Mg/Cu异种材料进行连接,焊后利用扫描电镜和EDS对焊接接头的微观组织及元素扩散行为进行了研究.在焊接温度为500℃,焊接时间为5min,焊接压力为2MPa的工艺下,焊接接头最高抗拉强度为42 MPa.

  6. Microstructure and phase constitution near the interface of Cu/3003 torch brazing using Al Si La Sr filler

    International Nuclear Information System (INIS)

    It has been mainly studied in this paper on brazing of Cu to Al using Al.Si filler metal. The optimized scanning rate of 2.5 mm/s is first obtained through simulating the temperature field of Cu Al brazing process based on ANSYS software. Then the brazing of Cu C11000 to Al 3003 using Al.Si.La.Sr filler is carried out by torch brazing technology. It is found that the brazing seam region is mainly consisted of α Al solid solution and CuAl2 IMC. Further experimental results also show that the rare earth element La in filler metal can not only refine the grain, but also promote the dispersion of intermetallic compounds into the brazing seam, which significantly improves the brazing seam microstructure and mechanical properties of the joints

  7. Microstructure and strength of brazed joints of TiB2 cermet to TiAl-based alloys

    Institute of Scientific and Technical Information of China (English)

    李卓然; 冯吉才; 曹健

    2003-01-01

    In this study, TiB2 cermet and TiAl-based alloy are vacuum brazed successfully by using Ag-Cu-Ti filler metal. The microstructural analyses indicate that two reaction products, Ti(Cu, Al)2 and Ag based solid solution (Ag(s.s)), are present in the brazing seam, and the interface structure of the brazed joint is TiB2/TiB2+ Ag(s.s) /Ag(s.s)+Ti(Cu, Al)2/Ti(Cu, Al)2/TiAl. The experimental results show that the shear strength of the brazed TiB2/TiAl joints decreases as the brazing time increases at a definite brazing temperature. When the joint is brazed at 1 223 K for 5 min, a joint strength up to 173 MPa is achieved.

  8. Hardness, Microstructure, and Residual Stresses in Low Carbon Steel Welding with Post-weld Heat Treatment and Temper Bead Welding

    Science.gov (United States)

    Aloraier, Abdulkareem S.; Joshi, Suraj; Price, John W. H.; Alawadhi, Khaled

    2014-04-01

    This paper investigates the effects of post-weld heat treatment (PWHT) and temper bead welding (TBW) on hardness, microstructure and residual stresses in multi-layer welding on low carbon steel specimens made with two different weld geometries, viz. (1) smooth-contoured and (2) U-shaped. It was found that the PWHT technique gave overall lower hardness than the TBW technique, but the hardness values in both techniques were acceptable. Microscopy analysis showed that the TBW technique was more effective in tempering the heat affected zone as the grain size decreased slightly at the fusion line in spite of the higher temperature at the fusion line. Residual stresses measured using the hole-drilling method showed that the residual stress is not reduced below yield stress near the last bead solidified in TBW. Only PWHT gives low residual stress results in this area. High tensile residual stresses may result in sensitivity to fatigue loading.

  9. 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.

  10. Characterization of the Micro-Welding Process for Repair of Nickel Base Superalloys

    Science.gov (United States)

    Durocher, J.; Richards, N. L.

    2007-12-01

    Micro-welding is a low-heat input process whereby a metal or cermet, is deposited by the generation of a low-power arc between a consumable electrode and a substrate. The low-heat input of this process offers unique advantages over more common welding processes such as gas tungsten arc, plasma arc, laser, and electron beam welding. At present, the repair of turbine blades and vanes commonly involves gas tungsten arc welding and these components are susceptible to heat affected zone cracking during the weld repair process; vacuum brazing is also used but mainly on low-stress components such as stators. In this study, the low-heat input characteristic of micro-welding has been utilized to simulate repair of Inconel (Trade Mark of Special Metals) 625, Inconel 718, and Inconel 722 filler alloys to a cast Inconel 738 substrate. The effect of micro-welding process parameters on the deposition rate, coating quality, and substrate has been investigated.

  11. Interfacial microstructure and mechanical property of Ti6Al4V/A6061 dissimilar joint by direct laser brazing without filler metal and groove

    Energy Technology Data Exchange (ETDEWEB)

    Song, Zhihua, E-mail: zhsong@jwri.osaka-u.ac.jp [Joining and Welding Research Institute, Osaka University, Osaka, Ibaraki 567-0047 (Japan); Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education (China); Nakata, Kazuhiro [Joining and Welding Research Institute, Osaka University, Osaka, Ibaraki 567-0047 (Japan); Wu, Aiping [Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education (China); Liao, Jinsun [Kurimoto Ltd., Osaka 559-0021 (Japan)

    2013-01-10

    Laser brazing of Ti6Al4V and A6061-T6 alloys with 2 mm thickness was conducted by focusing laser beam on aluminum alloy side, and the effect of laser offset distance on microstructure and mechanical properties of the dissimilar butt joint was investigated. Laser offset has a great influence on the thickness of interfacial intermetallic compound (IMC) layer and the mechanical property of joint. The thickness of interfacial IMC layer is less than 500 nm, and the average tensile strength of the joint reaches 64% of aluminum base material strength, when suitable welding conditions are used. The interfacial IMC is TiAl{sub 3}. The formation of interfacial IMC layer and its effect on mechanical property of the joint are discussed in the present study.

  12. Combined Laser Beam Welding and Brazing Process for Aluminium Titanium Hybrid Structures

    Science.gov (United States)

    Möller, F.; Grden, M.; Thomy, C.; Vollertsen, F.

    The current state of the art in light-weight construction is - for the case of aircraft structures - the use of either aluminium or titanium. Whereas aluminium is light-weight and less expensive, titanium offers superior corrosion properties at higher cost. In order to combine the advantages of both materials, a hybrid Ti-Al structure is proposed for e.g. seat-track application. In this paper, an overview of the results from this research work and the accompanying thermo-mechanical simulations will be reported and discussed. On the basis of the development of an appropriate system technology, the process development will be described, focusing on the main influencing parameters of the process on joint properties.

  13. 49 CFR 178.50 - Specification 4B welded or brazed steel cylinders.

    Science.gov (United States)

    2010-10-01

    ... calculated shear strength at least 10 times the test pressure of the cylinder; gaskets required, adequate to... as the finished cylinder. (k) Physical test. A physical test must be conducted to determine yield strength, tensile strength, elongation, and reduction of area of material as follows: (1) The test...

  14. 49 CFR 178.55 - Specification 4B240ET welded or brazed cylinders.

    Science.gov (United States)

    2010-10-01

    ... tight fit and calculated shear strength at least 10 times the test pressure of the cylinder; gaskets... between knife edges, wedge shaped, 60° angle, rounded to 1/2 inch radius. (k) Physical test. A physical test must be conducted to determine yield strength, tensile strength, elongation, and reduction of...

  15. Characterization of Microstructure and Mechanical Properties of Resistance Spot Welded DP600 Steel

    OpenAIRE

    Ali Ramazani; Krishnendu Mukherjee; Aydemir Abdurakhmanov; Mahmoud Abbasi; Ulrich Prahl

    2015-01-01

    Resistance spot welding (RSW) as a predominant welding technique used for joining steels in automotive applications needs to be studied carefully in order to improve the mechanical properties of the spot welds. The objectives of the present work are to characterize the resistance spot weldment of DP600 sheet steels. The mechanical properties of the welded joints were evaluated using tensile-shear and cross-tensile tests. The time-temperature evolution during the welding cycle was measured. T...

  16. An Approach to Maximize Weld Penetration During TIG Welding of P91 Steel Plates by Utilizing Image Processing and Taguchi Orthogonal Array

    Science.gov (United States)

    Singh, Akhilesh Kumar; Debnath, Tapas; Dey, Vidyut; Rai, Ram Naresh

    2016-06-01

    P-91 is modified 9Cr-1Mo steel. Fabricated structures and components of P-91 has a lot of application in power and chemical industry owing to its excellent properties like high temperature stress corrosion resistance, less susceptibility to thermal fatigue at high operating temperatures. The weld quality and surface finish of fabricated structure of P91 is very good when welded by Tungsten Inert Gas welding (TIG). However, the process has its limitation regarding weld penetration. The success of a welding process lies in fabricating with such a combination of parameters that gives maximum weld penetration and minimum weld width. To carry out an investigation on the effect of the autogenous TIG welding parameters on weld penetration and weld width, bead-on-plate welds were carried on P91 plates of thickness 6 mm in accordance to a Taguchi L9 design. Welding current, welding speed and gas flow rate were the three control variables in the investigation. After autogenous (TIG) welding, the dimension of the weld width, weld penetration and weld area were successfully measured by an image analysis technique developed for the study. The maximum error for the measured dimensions of the weld width, penetration and area with the developed image analysis technique was only 2 % compared to the measurements of Leica-Q-Win-V3 software installed in optical microscope. The measurements with the developed software, unlike the measurements under a microscope, required least human intervention. An Analysis of Variance (ANOVA) confirms the significance of the selected parameters. Thereafter, Taguchi's method was successfully used to trade-off between maximum penetration and minimum weld width while keeping the weld area at a minimum.

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

    DEFF Research Database (Denmark)

    Nielsen, Kim Lau

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

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

    OpenAIRE

    Bekir ÇEVİK

    2013-01-01

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

  19. Using Taguchi method to optimize welding pool of dissimilar laser-welded components

    Science.gov (United States)

    Anawa, E. M.; Olabi, A. G.

    2008-03-01

    In the present work, CO 2 continuous laser welding process was successfully applied and optimized for joining a dissimilar AISI 316 stainless-steel and AISI 1009 low carbon steel plates. Laser power, welding speed and defocusing distance combinations were carefully selected with the objective of producing welded joint with complete penetration, minimum fusion zone size and acceptable welding profile. Fusion zone area and shape of dissimilar austenitic stainless-steel with ferritic low carbon steel were evaluated as a function of the selected laser welding parameters. Taguchi approach was used as statistical design of experiment (DOE) technique for optimizing the selected welding parameters in terms of minimizing the fusion zone. Mathematical models were developed to describe the influence of the selected parameters on the fusion zone area and shape, to predict its value within the limits of the variables being studied. The result indicates that the developed models can predict the responses satisfactorily.

  20. Influence of laser power on microstructure and mechanical properties of fiber laser-tungsten inert gas hybrid welded Mg/Cu dissimilar joints

    International Nuclear Information System (INIS)

    Highlights: • Mg and Cu were joined successfully by laser-TIG hybrid welding process. • Effect of laser power on welded-brazed joints was investigated. • Different newly formed compounds were identified at the Mg/Cu interface. • Al from Mg base metal played an important role in Mg–Al–Cu ternary compound. • Mg–Cu eutectic structure did little harm to mechanical properties. - Abstract: Fiber laser-tungsten inert gas (TIG) hybrid welding technique has been developed for lap joining of dissimilar metals AZ31B Mg alloy to pure copper (T2). The influence of laser power on microstructure and mechanical properties of joints was investigated. The results indicated that acceptable joints could be obtained by adjusting the laser power to the range of 2000–3000 W. In particular, at the laser power of 2500 W the average tensile shear strength reached a maximum of 45.3 MPa, representing a 57% joint efficiency relative to the Mg sheet. Greater or less than 2500 W would cause over or under reaction at the interface, which resulted in the poor joint strength. The different morphologies including Mg–Cu eutectic structure, Mg–Cu intermetallic compound and Mg–Al–Cu ternary intermetallic compound were identified at the Mg/Cu interface. All the joints fractured at the Mg/Cu interface. However, the fracture mode was found to differ. For 2500 W the surface was characterized by tearing edge, while that with poor joint strength was almost dominated by smooth surface or flat tear pattern

  1. Laser strobe weld pool vision for robotic arc welding

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

    Husain, N Abu; Khodaparast, H Haddad; Snaylam, A; James, S; Sharp, M; Dearden, G; Ouyang, H, E-mail: h.ouyang@liverpool.ac.u [Department of Engineering, Harrison Hughes Building, University of Liverpool, L69 3GH (United Kingdom)

    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.

  3. Interfacial metallurgy study of brazed joints between tungsten and fusion related materials for divertor design

    International Nuclear Information System (INIS)

    Highlights: • We created brazed joints between tungsten and EUROFER 97, Cu and SS316L with Au80Cu19Fe1 filler. • No elemental transitions were detected between the W and the AuCuFe filler in either direction. • Transition regions between filler to EUROFER97/316L showed similar elastic modulus and hardness to the filler. • Smooth elemental and mechanical properties transition were detected between the filler and Cu. - Abstract: In the developing DEMO divertor, the design of joints between tungsten to other fusion related materials is a significant challenge as a result of the dissimilar physical metallurgy of the materials to be joined. This paper focuses on the design and fabrication of dissimilar brazed joints between tungsten and fusion relevant materials such as EUROFER 97, oxygen-free high thermal conductivity (OFHC) Cu and SS316L using a gold based brazing foil. The main objectives are to develop acceptable brazing procedures for dissimilar joining of tungsten to other fusion compliant materials and to advance the metallurgical understanding within the interfacial region of the brazed joint. Four different butt-type brazed joints were created and characterised, each of which were joined with the aid of a thin brazing foil (Au80Cu19Fe1, in wt.%). Microstructural characterisation and elemental mapping in the transition region of the joint was undertaken and, thereafter, the results were analysed as was the interfacial diffusion characteristics of each material combination produced. Nano-indentation tests are performed at the joint regions and correlated with element composition information in order to understand the effects of diffused elements on mechanical properties. The experimental procedures of specimen fabrication and material characterisation methods are presented. The results of elemental transitions after brazing are reported. Elastic modulus and nano-hardness of each brazed joints are reported

  4. Modeling of fundamental phenomena in welds

    Energy Technology Data Exchange (ETDEWEB)

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

    1993-12-31

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

  5. 铝制冷却器真空钎焊接头界面结构及断口分析%Interface Structure and Fracture Analysis of Aluminum Cooler Vacuum Brazing Joint

    Institute of Scientific and Technical Information of China (English)

    许敬年; 曹秀丽; 冯涛

    2012-01-01

    采用真空钎焊技术研制了一种用于高级轿车的铝制冷却器.采用LT-3铝复合板材进行了焊接试验,分析了钎焊接头的组织,并对所试制的铝制板翅式冷却器进行了水压试验及其断口分析.结果表明,钎焊接头中生成了网状共晶组织,接头中生成了金属间化合物.焊接完成的板翅式冷却器水压试验压力可达到15 kg/cm2以上,钎焊接头断口属于混合断裂,断口表面分布有二次裂纹、韧窝、解理面、沿晶断裂等断裂特征.%A kind of aluminum cooler used for advanced car by adopting vacuum brazing technology was developed. Welding test was conducted by Utilizing LT-3 aluminum composite plate. The structure of brazing joint was analyzed, and hydrostatic test and fracture analysis on fin type cooler of trial produced aluminum composite plate were carried out. The results showed that there are some reticular eutectic structures and intermetallic compound in the brazing joint. The hydrostatic test pressure of fine type cooler can reach more than 15 kg/cm2, the fracture type of the brazing joint is mixed fracture, and secondary cracks, dimples, cleavage planes and intergranular fracture etc. distribute on the surface of the fracture.

  6. 保温时间对Mg/Cu共晶反应钎焊连接的影响%Effects of Holding Time on Eutectic Contacting Reaction Brazing of Mg/Cu

    Institute of Scientific and Technical Information of China (English)

    王怀建; 白莉

    2012-01-01

    Magnesium alloy and copper were bonded by eutectic contacting reaction brazing, and the effects of holding time on the microstructure and tensile properties were studied. The results from the experiment show that when the welding process is 500℃ keeping for 30 min, welding pressure is 2MPa, the tensile strength can reach 54MPa.%采用共晶钎焊工艺对Mg/Cu异种材料进行连接,研究了不同保温时间对接头微观组织及力学性能的影响.结果表明,在焊接温度为500℃、保温时间为30 min、焊接压力为2MPa的工艺下,焊接接头最高抗拉强度为54 MPa.

  7. Distortion Control during Welding

    NARCIS (Netherlands)

    Akbari Pazooki, A.M.

    2014-01-01

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

  8. 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.…

  9. Diffusion bonding and brazing of high purity copper for linear collider accelerator structures

    Science.gov (United States)

    Elmer, J. W.; Klingmann, J.; van Bibber, K.

    2001-05-01

    Diffusion bonding and brazing of high purity copper were investigated to develop procedures for joining precision machined copper components for the Next Linear Collider (NLC). Diffusion bonds were made over a range of temperatures from 400 °C to 1000 °C, under two different loading conditions [3.45 kPa (0.5 psi) and 3.45 MPa (500 psi)], and on two different diamond machined surface finishes. Brazes were made using pure silver, pure gold, and gold-nickel alloys, and different heating rates produced by both radiation and induction heating. Braze materials were applied by both physical vapor deposition (PVD) and conventional braze alloy shims. Results of the diffusion bonding experiments showed that bond strengths very near that of the copper base metal could be made at bonding temperatures of 700 °C or higher at 3.45 MPa bonding pressure. At lower temperatures, only partial strength diffusion bonds could be made. At low bonding pressures (3.45 kPa), full strength bonds were made at temperatures of 800 °C and higher, while no bonding (zero strength) was observed at temperatures of 700 °C and lower. Observations of the fracture surfaces of the diffusion bonded samples showed the effects of surface finish on the bonding mechanism. These observations clearly indicate that bonding began by point asperity contact, and flatter surfaces resulted in a higher percentage of bonded area under similar bonding conditions. Results of the brazing experiments indicated that pure silver worked very well for brazing under both conventional and high heating rate scenarios. Similarly, pure silver brazed well for both the PVD layers and the braze alloy shims. The gold and gold-containing brazes had problems, mainly due to the high diffusivity of gold in copper. These problems led to the necessity of overdriving the temperature to ensure melting, the presence of porosity in the joint, and very wide braze joints. Based on the overall findings of this study, a two-step joining method

  10. Finite element analysis on electron beam brazing temperature and stresses of stainless steel radiator

    Institute of Scientific and Technical Information of China (English)

    Chen Furong; Liu Jun; Xie Ruijun; Liu Fangjun; Hu Gang

    2006-01-01

    Based on thermal-elasto-plastic finite element theory, a two-dimensional finite element model for calculating electron beam brazing temperature and residual stress fields of stainless steel radiator are presented.The distributions of temperature and residual stress are studied.The results showed that temperature distribution on brazing surface is rather uniform, ranging from 1026 ℃ to 1090 ℃.The residual stresses are varied from initial compressive to tensile , and the variation of residual stress is very little in total zone of brazing surface.

  11. Vacuum Brazing of Beryllium Copper Components for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Tyhurst, C.C.; Cunningham, M.A.

    2002-06-04

    A process for vacuum brazing beryllium copper anode assemblies was required for the Plasma Electrode Pockels Cell System, or PEPC, a component for the National Ignition Facility (NIF). Initial problems with the joint design and wettability of the beryllium copper drove some minor design changes. Brazing was facilitated by plating the joint surface of the beryllium copper rod with silver 0.0006 inch thick. Individual air sampling during processing and swipe tests of the furnace interior after brazing revealed no traceable levels of beryllium.

  12. Design of Fully Automatic Nitrogen Protection Brazing Furnace of Automotive Air Conditioning Radiator%汽车空调散热器全自动氮气保护钎焊炉的研制

    Institute of Scientific and Technical Information of China (English)

    陈明非; 汪娜

    2012-01-01

    全自动氮气保护钎焊炉是汽车空调散热器铝材焊接的关键设备.钎焊的工艺是将装配好的汽车空调散热器的芯体送入钎焊炉,经喷淋焊剂、干燥炉烘干、加热炉进行焊接,然后通过水冷室、风冷室进行冷却完成散热器的钎焊.技术关键是加热炉钎焊温度和含氧量的控制.通常采用在钎焊过程中向炉内充氮气,使炉内含氧量控制在70ppm以下.加热炉的进出口设置前室和后室,内置不锈钢幕帘阻挡空气的混入.介绍该设备的结构、部件、主要技术参数以及调试办法等.%The NB type entire automatic nitrogen protection brazing furnace is the essential equipment in aluminum welding. The brazing process includes sending the core of the assembled automotive air conditioning radiator into the brazing furnace, through being sprayed the flux,dried in the drying oven and heating furnace to weld, and then the welding is completed after being cooled in the cooling room and air cooling room.The key technology is the control of the temperature and the oxygen content of furnace braz ing.lt is commonly used to aerate nitrogen during the brazing process into the furnace,to guarantee oxygen content in the furnace is controlled below 70ppm.The import and export of the furnace is set with the front room and after room,with built—in stainless steel curtain to block the air.The structure of the equipment, components, main technical parameters as well as debugging approach is introduced.

  13. Non-destructive Magnetic Evaluation of Laser Weld Quality in Hot Rolled Coils

    Science.gov (United States)

    Mohapatra, J. N.; Chakradhar, I.; Rao, K. R. C.; Rao, V. V. L.; Kaza, Marutiram

    2015-06-01

    Weld quality evaluation was conducted on laser welded thin sectsions (2 mm) of hot-rolled (HR) low-carbon steel coils during cold rolling process. The analysis revealed that the poor welds consisting of the weld defects like incomplete fusion, cluster of porosity, and large difference in hardness between the weld zone and base metal were responsible for the weld failures. Experiments were conducted by varying the welding parameters; laser power and welding speed to optimize the parameters for minimizing the weld defects. The optimized weld process parameters have helped elimination of weld defects and the results are verified with microscopy and microhardness measurements. As destructive evaluation techniques are time consuming and not always permitted in industrial applications, attempts have been made in the present investigation for the utilization of suitable non-destructive techniques for the evaluation of weld quality. Non-destructive magnetic techniques of magnetic hysteresis loop and magnetic Barkhausen emissions were used in the present investigation to establish possible correlations of magnetic properties across the weld seam with the mechanical property (microhardness) for evaluation of weld quality. It is inferred that the magnetic properties of coercivity and inverse of root mean square voltage can be effectively utilized to determine weld quality in HR steel coils.

  14. Laser welding in space

    Science.gov (United States)

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

    1991-01-01

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

  15. “Effect of Tool Geometries on Thermal and Mechanical Behaviour of Friction Stir Welding Welds of Aluminum Alloy”

    Directory of Open Access Journals (Sweden)

    Kuber Singh Patel

    2016-06-01

    Full Text Available Friction stir welding is an advanced solid state joining technique, widely being used in various applications for joining aluminum alloys in aerospace, marine, automotive and many other applications of profitable importance. The welding parameters and tool pin profile play a major role in deciding the weld quality. It is an attempt to being made to analyze the effect of tool geometries, the effect of tool rotation and welding speeds on the mechanical properties of friction stir welded joints made for sample of profitable grade aluminum alloy and ANSYS is used to compare and prove the attempts made for various analyses

  16. 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.

  17. 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

  18. Fatigue properties of laser-brazed joints of Dual Phase and TRansformation Induced Plasticity steel with a copper-aluminium consumable

    International Nuclear Information System (INIS)

    High strength steels combine good formability with excellent mechanical properties and have developed continuously in recent years. Joining these materials is however increasingly difficult as fusion joining processes destroy the carefully constructed microstructure. To counteract this problem, joining processes which require less heat input have been investigated. Laser brazing is a relatively new technique and a potential candidate which has found application in the automotive industry. In this paper the fatigue lifetime properties of laser-brazed Dual Phase (DP600) and TRansformation Induced Plasticity (TRIP700) steel joints made with a copper-aluminium consumable are reported. Joints created with DP600 steel showed fracture through the steel due to a brass present in the stress concentration region at the edge of the reinforcement. TRIP700 steels show similar results if the applied maximum stress is in excess of 280 MPa. However, at maximum stresses of 230 MPa, failure occurred across the interface between the braze metal and the steel. A basic fatigue crack path model is presented for the two competing failure mechanisms.

  19. Active Metal Brazing and Characterization of Brazed Joints in C-C and C-SiC Composites to Copper-Clad-Molybdenum System

    Science.gov (United States)

    Singh, M.; Asthana, R.

    2008-01-01

    Carbon/carbon composites with CVI and resin-derived matrices, and C/SiC composites reinforced with T-300 carbon fibers in a CVI SiC matrix were joined to Cu-clad Mo using two Ag-Cu braze alloys, Cusil-ABA (1.75% Ti) and Ticusil (4.5% Ti). The brazed joints revealed good interfacial bonding, preferential precipitation of Ti at the composite/braze interface, and a tendency toward delamination in resin-derived C/C composite. Extensive braze penetration of the inter-fiber channels in the CVI C/C composites was observed. The Knoop microhardness (HK) distribution across the C/C joints indicated sharp gradients at the interface, and a higher hardness in Ticusil than in Cusil-ABA. For the C/SiC composite to Cu-clad-Mo joints, the effect of composite surface preparation revealed that ground samples did not crack whereas unground samples cracked. Calculated strain energy in brazed joints in both systems is comparable to the strain energy in a number of other ceramic/metal systems. Theoretical predictions of the effective thermal resistance suggest that such joined systems may be promising for thermal management applications.

  20. Inspection of thick welded joints using laser-ultrasonic SAFT.

    Science.gov (United States)

    Lévesque, D; Asaumi, Y; Lord, M; Bescond, C; Hatanaka, H; Tagami, M; Monchalin, J-P

    2016-07-01

    The detection of defects in thick butt joints in the early phase of multi-pass arc welding would be very valuable to reduce cost and time in the necessity of reworking. As a non-contact method, the laser-ultrasonic technique (LUT) has the potential for the automated inspection of welds, ultimately online during manufacturing. In this study, testing has been carried out using LUT combined with the synthetic aperture focusing technique (SAFT) on 25 and 50mm thick butt welded joints of steel both completed and partially welded. EDM slits of 2 or 3mm height were inserted at different depths in the multi-pass welding process to simulate a lack of fusion. Line scans transverse to the weld are performed with the generation and detection laser spots superimposed directly on the surface of the weld bead. A CCD line camera is used to simultaneously acquire the surface profile for correction in the SAFT processing. All artificial defects but also real defects are visualized in the investigated thick butt weld specimens, either completed or partially welded after a given number of passes. The results obtained clearly show the potential of using the LUT with SAFT for the automated inspection of arc welds or hybrid laser-arc welds during manufacturing.

  1. Inspection of thick welded joints using laser-ultrasonic SAFT.

    Science.gov (United States)

    Lévesque, D; Asaumi, Y; Lord, M; Bescond, C; Hatanaka, H; Tagami, M; Monchalin, J-P

    2016-07-01

    The detection of defects in thick butt joints in the early phase of multi-pass arc welding would be very valuable to reduce cost and time in the necessity of reworking. As a non-contact method, the laser-ultrasonic technique (LUT) has the potential for the automated inspection of welds, ultimately online during manufacturing. In this study, testing has been carried out using LUT combined with the synthetic aperture focusing technique (SAFT) on 25 and 50mm thick butt welded joints of steel both completed and partially welded. EDM slits of 2 or 3mm height were inserted at different depths in the multi-pass welding process to simulate a lack of fusion. Line scans transverse to the weld are performed with the generation and detection laser spots superimposed directly on the surface of the weld bead. A CCD line camera is used to simultaneously acquire the surface profile for correction in the SAFT processing. All artificial defects but also real defects are visualized in the investigated thick butt weld specimens, either completed or partially welded after a given number of passes. The results obtained clearly show the potential of using the LUT with SAFT for the automated inspection of arc welds or hybrid laser-arc welds during manufacturing. PMID:27062646

  2. Parametric optimization of seam welding of stainless steel (SS 304) sheets

    Energy Technology Data Exchange (ETDEWEB)

    Krishnan, Muthuraman Pandi; Sait, Abdullah Naveen; Ravichandran, Manickam [Chendhuran College of Engineering and Technology, Pudukkottai, Tamilnadu (India)

    2015-06-01

    In the present study, seam welding process parameters were optimized for joining 306 stainless steel plates. Welding pressure, welding speed and welding temperature combinations were carefully selected with the objective of producing a weld joint with maximum impact strength and hardness. Taguchi technique was applied for optimizing the selected welding parameters. The factors used in this study consisted of pressure, welding speed and welding temperature, each of which had three levels in the study. L{sub 27} orthogonal array and corresponding levels were selected according to the aforementioned factors and experimental tests were performed. Signal-to-noise (S/N) ratio was used to evaluate the experimental results. The results indicate that the welding speed has the greatest influence on impact strength, followed by welding pressure and temperature. Experiments have also been conducted to validate the optimized parameters.

  3. Effect of beam oscillation on borated stainless steel electron beam welds

    International Nuclear Information System (INIS)

    Borated stainless steels are used in nuclear power plants to control neutron criticality in reactors as control rods, shielding material, spent fuel storage racks and transportation casks. In this study, bead on plate welds were made using gas tungsten arc welding (GTAW) and electron beam welding (EBW) processes. Electron beam welds made using beam oscillation technique exhibited higher tensile strength values compared to that of GTA welds. Electron beam welds were found to show fine dendritic microstructure while GTA welds exhibited larger dendrites. While both processes produced defect free welds, GTA welds are marked by partially melted zone (PMZ) where the hardness is low. EBW obviate the PMZ failure due to low heat input and in case of high heat input GTA welding process failure occurs in the PMZ.

  4. Laser welding of the 12Kh18N10T steel

    International Nuclear Information System (INIS)

    A possibility of laser welding of 5 and 6 mm thick butt joints of the 12Kh18N10T stainless steel has been studied. The laser beam power constituted 5 and 23 kW and rates-75 and 250 m/h, respectively. Both two-sided air blasting of the molten pool by helium and the AN-60 flux were used for the weld metal protection from oxidation. The quality of welding was assessed on the basis of the results metallographic and X-ray structural analyses of welds and mechanical tests. The effect of welding parameters and weld metal protection technique on the quality of welded joints has been shown. The mechanical properties of welded joints are satisfactory. It has been made the conclusion on the possibility of laser welding of the above steel for the weld metal protection from oxidation using fluxes and inert gases

  5. Progress in welding studies for Canadian nuclear fuel waste disposal containers

    International Nuclear Information System (INIS)

    This report describes the progress in the development of closure-welding technology for Canadian nuclear fuel waste disposal containers. Titanium, copper and Inconel 625 are being investigated as candidate materials for fabrication of these containers. Gas-tungsten-arc welding, gas metal-arc-welding, resistance-heated diffusion bonding and electron beam welding have been evaluated as candidate closure welding processes. Characteristic weldment properties, relative merits of welding techniques, suitable weld joint configurations and fit-up tolerances, and welding parameter control ranges have been identified for various container designs. Furthermore, the automation requirements for candidate welding processes have been assessed. Progress in the development of a computer-controlled remote gas-shielded arc welding system is described

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

    Science.gov (United States)

    Poppas, D P; Scherr, D S

    1998-07-01

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

  7. Prediction of Welding Deformation and Residual Stresses in Fillet Welds Using Indirect Couple Field FE Method

    Directory of Open Access Journals (Sweden)

    Asifa Khurram

    2013-03-01

    Full Text Available Fillet welds are extensively used in shipbuilding, automobile and other industries. Heat concentrated at a small area during welding induces distortions and residual stresses, affecting the structural strength. In this study, indirect coupled-field method is used to predict welding residual stresses and deformation in a fillet joint due to welding on both sides. 3-D nonlinear thermal finite element analysis is performed in ANSYS software followed by a structural analysis. Symmetrical boundary conditions are applied on half of the model for simplification. Results of FE structure analysis predict residual stresses in the specimen. A comparison of simulation results with experimental values proves the authenticity of the technique. The present study can be extended for complex structures and welding techniques.

  8. Development of Induction Brazing System for Sealing Instrumentation Feed through Part of Nuclear Fuel Test Rig

    International Nuclear Information System (INIS)

    To test the performance of nuclear fuels, coolant needs to be circulated through the test rig installed in the test loop. Because the pressure and temperature of the coolant is 15.5 MPa and 300 .deg. C respectively, coolant sealing is one of the most important processes in fabricating a nuclear fuel test rig. In particular, 15 instrumentation cables installed in a test rig pass through the pressure boundary, and brazing is generally applied as a sealing method. In this study, an induction brazing system has been developed using a high frequency induction heater including a vacuum chamber. For application in the nuclear field, BNi2 should be used as a paste, and optimal process variables for Ni brazing have been found by several case studies. The performance and soundness of the brazed components has been verified by a tensile test, cross section test, and sealing performance test

  9. An Investigation on Corrosion Behavior of a Multi-layer Modified Aluminum Brazing Sheet

    Directory of Open Access Journals (Sweden)

    Liu Wei

    2016-01-01

    Full Text Available The corrosion behavior of a multi-layer modified aluminum brazing sheet (AA4045/3003Mod./AA7072/AA4045 was investigated. The results shows that, the existence of BDP, which forms at the interface between clad and core layer during brazing, changes the corrosion form of the air side of the material from inter-granular corrosion to local exfoliation corrosion. The addition of anti-corrosion layer makes the corrosion form of the water side from inter-granular corrosion into uniform exfoliation corrosion. Compared to the normal triple-layer brazing sheet at the same thickness, the time to perforation of the modified four-layer brazing sheet is increased by more than 200%.

  10. Evaluation of the adhesion strength of diamond films brazed on K-10 type hard metal

    Directory of Open Access Journals (Sweden)

    Sérgio Ivan dos Santos

    2004-06-01

    Full Text Available The coating of cutting tools with diamond films considerably increases the tool performance due to the combination of the unique tribological properties of diamond with the bulk properties of the substrate (toughness. The tool performance, however, is strongly related to the adhesion strength between the film and the substrate. In this work our main goal was to propose and to test a procedure, based on a tensile strength test, to evaluate the adhesion strength of a diamond wafer brazed on a hard metal substrate, taking into account the effect of the brazing temperature and time. The temperature range studied was from 800 to 980 °C and the brazing time ranged from 3 to 40 min. The obtained results could be used to optimize the costs and time required to the production of high performance cutting tools with brazed diamond wafers.

  11. Studies and research on the microstructure of brazed aluminum alloys in the repair process

    Science.gov (United States)

    Dimitescu, A.; Amza, Gh; Niţoi, D. F.; Amza, C. Gh; Apostolescu, Z.

    2016-08-01

    In aeronautical industry, in recent years, brazing joints got a growing spread. Therefore, it is necessary a detailed study on the microstructure of the assembly base and filler material brazed in conditions of reconditioning operation [1]. The methods of destructive examination are not associated with any particular type of test piece but lay down the general principles of the types of testing described. It is emphasized that a satisfactory examination method can only be developed and used after taking into account all the relevant factors regarding the equipment to be used and the characteristics of the test pieces being examined. [1, 2]. Brazing joints are most often systematically designed to be resistant to shearing, and the size of the joint influences the shear strength more than the tensile strength. Studies and researches on the microstructure may be necessary to determine the effects of brazing process or of any subsequent heat treatment on the characteristics of the joint.

  12. Simulation on Thermal Integrity of the Fin/Tube Brazed Joint of Heat Exchangers

    Institute of Scientific and Technical Information of China (English)

    Yiyu QIAN; Feng GAO; Fengjiang WANG; Hui ZHAO

    2003-01-01

    In the applications of heat exchangers, the fin efficiency of heat transfer is the key issue. Thermal distribution withinthe brazed joints in heat exchanger under loading conditions is investigated in this paper. Simulated results showedthat the therma

  13. Researches and studies regarding brazed aluminium alloys microstructure used in aeronautic industry

    Directory of Open Access Journals (Sweden)

    A. Dimitrescu

    2015-04-01

    Full Text Available Brazing is applied to the merge of the pieces which are most required, tensile strength of the solder can reach high values. By brazing there can be assembled pieces of most metals and ferrous and nonferrous alloys, with high melting temperature. This paper presents an analysis of the microstructure of materials from a brazed merge of aluminum alloy L103 which is often used to produce pieces of aeronautical industry. Brazing material was performed using several technologies, and after examination of the microstructure of materials from the merge area it was established as optimal technology the technology which consist of pickling in Aloclene 100 solution with the deposition of filler material on both sides of the base material and the use of spectral acetylene and neutral flame.

  14. Electrochemical depth profiling of multilayer metallic structures: An aluminum brazing sheet

    DEFF Research Database (Denmark)

    Afshar, F. Norouzi; Ambat, R.; Kwakernaak, C.;

    2012-01-01

    Combinatory localized electrochemical cell and glow discharge optical emission spectrometry (GDOES) measurements were performed to obtain a thorough in depth electrochemical characterization of an aluminum brazing sheet. By defining electrochemical criteria i.e. breakdown potential, corrosion pot...

  15. Nano-Phase Powder Based Exothermic Braze Repair Technology For RCC Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — MRi is proposing, with its partner, Exotherm Corp (Camden, NJ) to demonstrate the feasibility of using exothermic brazing to join RCC (or C:SiC) composites to...

  16. Nano-Phase Powder Based Exothermic Braze Repair Technology For RCC Materials Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Phase II project will advance innovative, cost effective and reliable nano-phase exothermic RCC joining processes (ExoBrazeTM) in order to be able to reinforce...

  17. Residual stress study by neutron diffraction in the Charpy specimens reconstructed by various welding methods

    International Nuclear Information System (INIS)

    The investigation of welding residual stress is very important for nuclear industry since it can considerably affect the structural integrity of various components and products and their lifetime. In order to evaluate the applicability of various welding methods the residual stress in test Charpy specimens welded by various techniques were analysed using high resolution neutron diffraction. The experiments show that the level of residual stress in welds can be quite high and this fact should be considered when choosing an appropriate welding technique. Key words: neutron diffraction, residual stress, welding

  18. The Studies of the Welding Processes and Procedures on the West-East Pipeline Project

    Institute of Scientific and Technical Information of China (English)

    SuiYongli; HuangFuxiang; ZhaoHaihong; YinChanghua

    2004-01-01

    The West-East pipeline project attracted the attention from all over the world for its long distance, huge diameter, complex geographic conditions, and diversified welding techniques being applied. In this paper the detail welding process and procedures used in the project are discussed and the distinguished achievements on welding techniques of China pipeline construction are described.

  19. Brazing of 14-5 PH steel and WC-Co sinterson considerable dimension surfaces

    Directory of Open Access Journals (Sweden)

    J. Nowacki

    2007-03-01

    Full Text Available Purpose: of this paper is study of structure properties of considerable surfaces vacuum brazed joints of WC-Co sinters and precipitation hardened stainless steel of 14-5 PH using copper and silver-copper as the brazing filler metal.Design/methodology/approach: the joints are used in large dimension spinning nozzles of a die for polyethylene granulation, in that considerable strength and ductility of the joints are required. Structure and mechanical properties of joints have been described. Shear strength Rt and tensile strength Rm of the joints have been defined.Findings: to have been state, that the basic factors decreasing quality of the joint, which can occur during vacuum brazing of the WC-Co ISO K05 sinter – Cu or Ag-Cu brazing filler metal – 14-5 PH steel joints are diffusive processes leading to exchange of elements of cermets and the brazing filler metal and creation of intermetalics in the joint. It can have an unfavourable influence on ductility of sinters and quality of joint. As a result of brazing tests the influence of means and parameters of the brazing on quality of a joint was determined.Research limitations/implications: as a result of the experiments scheme of the joint structure WC-Co ISO K05 sinter – Cu brazing filler metal – 14-5 PH steel joint and WC-Co ISO K05 sinter – Cu brazing filler metal – 14-5 PH have been described.Practical implications: as a result of conducted experiments a production of spinning nozzle of a die for polyethylene granulation with a vacuum-brazed with a WC-Co ISO K05 sinters plates cutting surface of large surfaces on precipitation hardened stainless steel 14-5 PH have been worked out and industrial applied.Originality/value: the basic factors decreasing quality of the joint, which can occur while vacuum brazing of stainless steels and cermets have been determined.

  20. Analysis and Comparison of Friction Stir Welding and Laser Assisted Friction Stir Welding of Aluminum Alloy

    Directory of Open Access Journals (Sweden)

    Sabina Luisa Campanelli

    2013-12-01

    Full Text Available Friction Stir Welding (FSW is a solid-state joining process; i.e., no melting occurs. The welding process is promoted by the rotation and translation of an axis-symmetric non-consumable tool along the weld centerline. Thus, the FSW process is performed at much lower temperatures than conventional fusion welding, nevertheless it has some disadvantages. Laser Assisted Friction Stir Welding (LAFSW is a combination in which the FSW is the dominant welding process and the laser pre-heats the weld. In this work FSW and LAFSW tests were conducted on 6 mm thick 5754H111 aluminum alloy plates in butt joint configuration. LAFSW is studied firstly to demonstrate the weldability of aluminum alloy using that technique. Secondly, process parameters, such as laser power and temperature gradient are investigated in order to evaluate changes in microstructure, micro-hardness, residual stress, and tensile properties. Once the possibility to achieve sound weld using LAFSW is demonstrated, it will be possible to explore the benefits for tool wear, higher welding speeds, and lower clamping force.

  1. Brazing of 14-5 PH steel and WC-Co sinterson considerable dimension surfaces

    OpenAIRE

    J. Nowacki

    2007-01-01

    Purpose: of this paper is study of structure properties of considerable surfaces vacuum brazed joints of WC-Co sinters and precipitation hardened stainless steel of 14-5 PH using copper and silver-copper as the brazing filler metal.Design/methodology/approach: the joints are used in large dimension spinning nozzles of a die for polyethylene granulation, in that considerable strength and ductility of the joints are required. Structure and mechanical properties of joi...

  2. Low temperature friction stir welding of P91 steel

    Directory of Open Access Journals (Sweden)

    Prasad Rao Kalvala

    2016-08-01

    Full Text Available Bead-on-plate friction stir welds were made on P91 alloy with low and high rotational speeds (100 and 1000 RPM to study their effects on weld microstructural changes and impression creep behavior. Temperatures experienced by the stir zone were recorded at the weld tool tip. Different zones of welds were characterized for their microstructural changes, hardness and creep behavior (by impression creep tests. The results were compared with submerged arc fusion weld. Studies revealed that the stir zone temperature with 100 RPM was well below Ac1 temperature of P91 steel while it was above Ac3 with 1000 RPM. The results suggest that the microstructural degradation in P91 welds can be controlled by low temperature friction stir welding technique.

  3. High power Nd:YAG laser welding in manufacturing of vacuum vessel of fusion reactor

    International Nuclear Information System (INIS)

    Laser welding has shown many advantages over traditional welding methods in numerous applications. The advantages are mainly based on very precise and powerful heat source of laser light, which change the phenomena of welding process when compared with traditional welding methods. According to the phenomena of the laser welding, penetration is deeper and thus welding speed is higher. Because of the precise power source and high-welding speed, the heat input to the workpiece is small and distortions are reduced. Also, the shape of laser weld is less critical for distortions than traditional welds. For welding thick sections, the usability of lasers is not so practical than with thin sheets, because with power levels of present Nd:YAG lasers depth of penetration is limited up to about 10 mm by single-pass welding. One way to overcome this limitation is to use multi-pass laser welding, in which narrow gap and filler wire is applied. By this process, thick sections can be welded with smaller heat input and then smaller distortions and the process seems to be very effective comparing 'traditional' welding methods, not only according to the narrower gap. Another way to increase penetration and fill the groove is by using the so-called hybrid process, in which laser and GMAW (gas metal arc welding) are combined. In this paper, 20-mm thick austenitic stainless steel was welded using narrow gap configuration with a multi-pass technique. Two welding procedures were used: Nd:YAG laser welding with filler wire and with addition of GMAW, the hybrid process. In the welding experiments, it was noticed that both processes are feasible for welding thicker sections with good quality and with minimal distortions. Thus, these processes should be considered when the evaluation of the welding process is done for joining vacuum vessel sectors of ITER

  4. High power Nd:YAG laser welding in manufacturing of vacuum vessel of fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Jokinen, Tommi E-mail: tommi.jokinen@vtt.fi; Kujanpaeae, Veli E-mail: veli.kujanpaa@lut.fi

    2003-09-01

    Laser welding has shown many advantages over traditional welding methods in numerous applications. The advantages are mainly based on very precise and powerful heat source of laser light, which change the phenomena of welding process when compared with traditional welding methods. According to the phenomena of the laser welding, penetration is deeper and thus welding speed is higher. Because of the precise power source and high-welding speed, the heat input to the workpiece is small and distortions are reduced. Also, the shape of laser weld is less critical for distortions than traditional welds. For welding thick sections, the usability of lasers is not so practical than with thin sheets, because with power levels of present Nd:YAG lasers depth of penetration is limited up to about 10 mm by single-pass welding. One way to overcome this limitation is to use multi-pass laser welding, in which narrow gap and filler wire is applied. By this process, thick sections can be welded with smaller heat input and then smaller distortions and the process seems to be very effective comparing 'traditional' welding methods, not only according to the narrower gap. Another way to increase penetration and fill the groove is by using the so-called hybrid process, in which laser and GMAW (gas metal arc welding) are combined. In this paper, 20-mm thick austenitic stainless steel was welded using narrow gap configuration with a multi-pass technique. Two welding procedures were used: Nd:YAG laser welding with filler wire and with addition of GMAW, the hybrid process. In the welding experiments, it was noticed that both processes are feasible for welding thicker sections with good quality and with minimal distortions. Thus, these processes should be considered when the evaluation of the welding process is done for joining vacuum vessel sectors of ITER.

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

    OpenAIRE

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

    2009-01-01

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

  6. Welded solar cell interconnection

    Science.gov (United States)

    Stofel, E. J.; Browne, E. R.; Meese, R. A.; Vendura, G. J.

    1982-01-01

    The efficiency of the welding of solar-cell interconnects is compared with the efficiency of soldering such interconnects, and the cases in which welding may be superior are examined. Emphasis is placed on ultrasonic welding; attention is given to the solar-cell welding machine, the application of the welding process to different solar-cell configurations, producibility, and long-life performance of welded interconnects. Much of the present work has been directed toward providing increased confidence in the reliability of welding using conditions approximating those that would occur with large-scale array production. It is concluded that there is as yet insufficient data to determine which of three methods (soldering, parallel gap welding, and ultrasonic welding) provides the longest-duration solar panel life.

  7. Tensile fracture characterization of braze joined copper-to-CFC coupon assemblies

    Science.gov (United States)

    Trester, P. W.; Valentine, P. G.; Johnson, W. R.; Chin, E.; Reis, E. E.; Colleraine, A. P.

    1996-10-01

    A vacuum brazing process was used to join a broad spectrum of carbon-fiber reinforced carbon matrix composite (CFC) materials, machined into cylindrical coupons, between coupons of oxygen-free copper, the braze alloy was a copper-base alloy which contained only low activation elements (Al, Si, and Ti) relative to a titanium baseline specification. This demonstration was of particular importance for plasma facing components (PFCs) under design for use in the Tokamak Physics Experiment (TPX); the braze investigation was conducted by General Atomics for the Princeton Plasma Physics Laboratory. A tensile test of each brazed assembly was conducted. The results from the braze processing, testing, and fracture characterization studies of this reporting support the use of CFC's of varied fiber architecture and matrix processing in PFC designs for TPX. Further, the copper braze alloy investigated is now considered to be a viable candidate for a low-activation bond design. The prediction of plasma disruption-induced loads on the PFCs in TPX requires that joint strength between CFC tiles and their copper substrate be considered in design analysis and CFC selection.

  8. JOINING OF MOLYBDENUM DISILICIDE TO STAINLESS STEEL USING AMORPHOUS METAL BRAZES-RESIDUAL STRESS ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    VAIDYA, RAJENDRA U [Los Alamos National Laboratory; KAUTZ, DOUGLAS D. [Los Alamos National Laboratory; GALLEGOS, DAVID E. [Los Alamos National Laboratory

    2007-01-30

    Molybdenum disilicide (MoSi{sub 2})/stainless steel 316 L jOints were produced by high temperature brazing using a cobalt-based metallic-glass (METGLAS{trademark} 2714A). Successful joining was completed in two different ways; either by feeding excess braze into the braze gap upon heating or by constraining the MoSi{sub 2}/stainiess steel assembly with an alumina (Al{sub 2}O{sub 3}) fixture during the heating cycle. These steps were necessary to ensure the production of a high quality void free joint. Residual stress measurements were completed on these joints. Indentation results show higher tensile residual stresses in the stainless steel for the joint with the external constraint, in comparison to the unconstrained state. In contrast, the compressive residual stresses In the MoSi{sub 2} (as measured by X-ray diffraction) were lower in the constrained state relative to the unconstrained state. These results and a lack of residual stress balance indicate that the stress state in the braze is significantly different under the two joining conditions and the volume of the braze plays an important role in the development of the residual stresses. Push-out tests carried out on these joints gave higher joint strengths in the unconstrained as compared to the constrained condition. The results of this study have important implications on the selection of the appropriate joining process (use of constraint versus extra braze).

  9. Laser brazing of inconel 718 alloy with a silver based filler metal

    Science.gov (United States)

    Khorram, A.; Ghoreishi, M.; Torkamany, M. J.; Bali, M. M.

    2014-03-01

    In the presented study laser brazing of an inconel 718 alloy with silver based filler metal using 400 W pulsed Nd:YAG laser is investigated. Laser brazing was performed with varying laser frequency, pulse width, process speed and gap distance. The effect of preheating on wetting and spreading also was studied. Brazing geometrical images were observed using an optical microscope. The composition analysis and microstructure of the filler metal and brazed joints were examined using X-ray diffraction analyzer (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Micro-hardness and tensile test were performed for investigation of mechanical properties. The experimental observations show that filler metal consist of α-Ag solid solution, ά-Cu solid solution surround by the α-Ag solid solution and eutectic structure. Phases of the brazed joint are similar to the filler metal. The results indicate that the filler metal has adequate wetting and spreading on inconel 718 and the wetting angle depends on the heat input significantly. Interdiffusion occurs in laser brazing and the average thickness of reaction layer is approximately 2.5 μm. Whenever the gap is big, it is needed to use longer pulse width in order to have a better melting flow. Preheating has significant influence on wetting and spreading of the filler metal.

  10. Joining and fabrication techniques for high temperature structures including the first wall in fusion reactor

    International Nuclear Information System (INIS)

    The materials for PFC's (Plasma Facing Components) in a fusion reactor are severely irradiated with fusion products in facing the high temperature plasma during the operation. The refractory materials can be maintained their excellent properties in severe operating condition by lowering surface temperature by bonding them to the high thermal conducting materials of heat sink. Hence, the joining and bonding techniques between dissimilar materials is considered to be important in case of the fusion reactor or nuclear reactor which is operated at high temperature. The first wall in the fusion reactor is heated to approximately 1000 .deg. C and irradiated severely by the plasma. In ITER, beryllium is expected as the primary armour candidate for the PFC's; other candidates including W, Mo, SiC, B4C, C/C and Si3N4. Since the heat affected zones in the PFC's processed by conventional welding are reported to have embrittlement and degradation in the sever operation condition, both brazing and diffusion bonding are being considered as prime candidates for the joining technique. In this report, both the materials including ceramics and the fabrication techniques including joining technique between dissimilar materials for PFC's are described. The described joining technique between the refractory materials and the dissimilar materials may be applicable for the fusion reactor and Generation-4 future nuclear reactor which are operated at high temperature and high irradiation

  11. Joining and fabrication techniques for high temperature structures including the first wall in fusion reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Jin; Lee, B. S.; Kim, K. B

    2003-09-01

    The materials for PFC's (Plasma Facing Components) in a fusion reactor are severely irradiated with fusion products in facing the high temperature plasma during the operation. The refractory materials can be maintained their excellent properties in severe operating condition by lowering surface temperature by bonding them to the high thermal conducting materials of heat sink. Hence, the joining and bonding techniques between dissimilar materials is considered to be important in case of the fusion reactor or nuclear reactor which is operated at high temperature. The first wall in the fusion reactor is heated to approximately 1000 .deg. C and irradiated severely by the plasma. In ITER, beryllium is expected as the primary armour candidate for the PFC's; other candidates including W, Mo, SiC, B4C, C/C and Si{sub 3}N{sub 4}. Since the heat affected zones in the PFC's processed by conventional welding are reported to have embrittlement and degradation in the sever operation condition, both brazing and diffusion bonding are being considered as prime candidates for the joining technique. In this report, both the materials including ceramics and the fabrication techniques including joining technique between dissimilar materials for PFC's are described. The described joining technique between the refractory materials and the dissimilar materials may be applicable for the fusion reactor and Generation-4 future nuclear reactor which are operated at high temperature and high irradiation.

  12. Appliances and technologies on mechanical welding of reactor shells

    International Nuclear Information System (INIS)

    Nowadays, welded joints of spherical reactor safety shells are generally and to a large extent produced by manual arc-welding. Mechanized welding methods are to be developed aiming at obtaining better technological quality values, more safety with regard to susceptibility to pores and cracks and more independence from human insufficiency. Due to the lack of special machinery for the required purpose and due to the fact that expensive machinery developments should be avoided, a worldwide search on the market has been effected on the basis of given specifications in order to find convenient welding appliances which can be modified. The problems of the search for machinery as well as of laboratory experiments are shown in this report. An electro-gas/slag vertical welding method shall be developed being economic and assuring the quality values required for the vertical welding. For the welding of the upper and lower parts of the sphere a MIG/MAG-shielded arc-welding method with weld centerline and height-control is required which has to meet the same demands as well as a proper guiding on the shell. The initial experiments at the selected appliances shows the possibility to improve the welding quality considerably by mechanizing. The following topics are discussed in detail: sensor systems, oscillating systems, subsequent systems, electro-slag-high-speed-welding in single pass technique, machinery developments, pass and capping pass electro-slag-high-speed welding. Analysis of the used starting-, admixture- and auxilary material, testing conditions and welding parameters, quality values achieved at electro-slag-welds. Automatic MIG/MAG oscillating machines with electronic weld centerline and height control. Systems with the electric arc acting as sensor. Sources of current. (orig.)

  13. 换热器管板角焊缝相控阵自动超声检测技术研究%Research on Phased Array Automatically Ultrasonic Testing Technique of Tube to Tube-sheet Welds in Heat Exchanger

    Institute of Scientific and Technical Information of China (English)

    郭伟灿; 钱盛杰; 凌张伟

    2015-01-01

    在换热器的制作过程中,换热管与管板常采用焊接形式,焊缝的质量是保证换热器长期正常运行的关键。常规的超声检测方法具有系统复杂、检测效率低等缺点。因此,提出了相控阵超声检测技术,并开发了相控阵超声检测系统,以实现对管板角焊缝的自动超声检测。系统由周向步进电机实现周向扫查,纵向扫查采用相控阵探头电子线扫查,从而实现超声 C 扫描检测。通过带有气孔、未熔合等典型缺陷对检测系统进行试验研究。结果表明,该技术可以有效地检测出换热器管板角焊缝中的典型缺陷。%In the process of produce heat exchangers,heat exchanger′s tube and tube sheet conjunction adopt the form of welding,the quality of welding is the key insurance for the long and normal operation of the heat exchangers.The conventional ultrasonic testing method has many disadvantages like complicated system and low efficiency of detection.Thus,it puts forward the phased array ultrasonic testing technique and develops the ultrasonic testing system to accomplish the automatically ultrasonic testing of the tube to tube-sheet welds.The ultrasonic C-scan was carried out by the ultrasonic testing system with its circumfer-ential scanning by a mechanical scanning device while the axial electronic linear scanning by the phased array probe.At last,the tests on samples with typical flaws such as porosity flaws and the incomplete fu-sion flaws were performed by the ultrasonic testing system.Experiment results showed that the phased ar-ray ultrasonic technique could effectively detect the typical flaws in the tube to tube-sheet welds of heat exchanger.

  14. Inhibition of the formation of intermetallic compounds in aluminum-steel welded joints by friction stir welding

    International Nuclear Information System (INIS)

    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)

  15. A review on TIG welding for optimizing process parameters on dissimilar joints

    OpenAIRE

    Prashant Kumar Singh; Pankaj Kumar

    2015-01-01

    Tungsten Inert Gas Welding (TIG) is relatively high strength welding technique. This technique are mostly used in fabrication and other industries to join the either similar or dissimilar materials. In particular, it can be used to join high-quality strength of metal and alloys.In this paper we discuss abouttheTungsten Inert Gas welding of joining heat treatableof stainless steel and mild steel.These welded joints have higher tensile strength to weight ratio and finer micro struct...

  16. Determination of the sensitization of two coatings by steel welding 308l by the EPR-Dl and Astm A-262 practice A techniques; Determinacion de la sensibilizacion de dos revestimientos por soldadura de acero 308L por las tecnicas EPR-DL y ASTM A-262 practica A

    Energy Technology Data Exchange (ETDEWEB)

    Arganis J, C. R.; Zenteno S, J. C.; Robles F, J. L.; Rodriguez M, E.; Vazquez P, A., E-mail: carlos.arganis@inin.gob.mx [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)

    2014-10-15

    A stainless steel 308l coating was deposited by the shielded metal arc welding (SMAW) on steel A36 with a thickness of 4.726 mm in three layers. The sensitization was measured with the technique of Electrochemical Potentiodynamic Reactivation of Double-loop (EPR-Dl), using a portable cell and other of conventional window. The standard Astm A-262, practice A was used to verify the sensitization values. Two samples were used, a welding on a plate of 323 x 172 x 76.2 mm and the second welding on the end of a plate of 12.7 mm of thickness and 280 mm of longitude, with a post-welding process with gas tungsten arc welding (GTAW) with electrode ERNiCr{sub 3} and a process SMAW with electrode ENICRFe{sub 3}. The coating on the plate showed low values of sensitization grade (DOS) in all the points, indicating a very quick heat extraction and an inter dendritic structure type step. The second sample presented DOS values that are related with a structure of low sensitization and the influence of the heat of the post-welding process and a structure of recrystallized grains. (Author)

  17. Measurement of nugget size of spot weld by digital shearography

    Science.gov (United States)

    Yang, Lianxiang; Samala, Praveen R.; Liu, Sheng; Long, Kah Wah; Lee, Yung-Li

    2005-08-01

    Resistance spot welding is now widely used in the fabrication of sheet metals, mainly due to the cost and time considerations. Friction stir spot welding is getting more and more acceptance in the automotive industries. Such spot welds are found in nearly all products where sheet metal is joined. Obviously the quality of the spot weld has a direct impact on the quality of the product. The most important quality target of spot welds is the size of the weld nuggets. If the weld nuggets are improperly or incompletely formed, or the area surrounding the nugget is smaller than required, the structural integrity of the entire part may be uncertain. Furthermore these inconsistencies are usually internal and are seldom visible to optical inspection. This study is focused on the quality analysis of the spot welds by using "Digital Shearography". The paper mainly focuses on developing a novel, whole field technique for non-destructive inspecting the size of spot-welds, both for the resistance spot weld and the friction stir spot weld.

  18. MODELLING AND CHARACTERIZATION OF LASER WELDED INCOLOY 800 HT JOINTS

    Directory of Open Access Journals (Sweden)

    Sathiya Paulraj

    2016-06-01

    Full Text Available This study aims at finding the effect of laser welding speed on incoloy 800 HT. This alloy is one of the potential materials for Generation IV nuclear plants. Laser welding has several advantages over arc welding such as low fusion zone, low heat input and concentrated heat intensity. Three different welding speeds were chosen and CO2 laser welding was performed. 2D modeling and simulation were done using ANSYS 15 to find out the temperature distribution at different welding speeds and it was found that an increase in the welding speed decreased the temperature. Mechanical properties such as tensile strength, toughness and hardness were evaluated. The effect of welding speed on metallurgical characteristics was studied using optical microscopy (OM, Scanning Electron Microscopy (SEM with EDS, X-Ray Diffraction (XRD technique and fractographic analysis. From the results it was found that high welding speed (1400 mm/min decreased the joint strength. The M23C6 and Ni3Ti carbides were formed in a discrete chain and in a globular form along the grain boundaries of the weld region which increased the strength of the grain boundaries. Fractographic evaluations of the tested specimens for welding speed (1000 and 1200 mm/min showed deep and wide dimples indicating ductile failures.

  19. Polyethylene welding by pulsed visible laser irradiation

    Science.gov (United States)

    Torrisi, L.; Caridi, F.; Visco, A. M.; Campo, N.

    2011-01-01

    Laser welding of plastics is a relatively new process that induces locally a fast polymer heating. For most applications, the process involves directing a pulsed beam of visible light at the weld joint by going through one of the two parts. This is commonly referred to as “through transmission visible laser welding”. In this technique, the monochromatic visible light source uses a power ns pulsed laser in order to irradiate the joint through one part and the light is absorbed in the vicinity of the other part. In order to evaluate the mechanical resistance of the welded joint, mass quadrupole spectrometry, surface profilometry, microscopy techniques and mechanical shear tests were employed. The welding effect was investigated as a function of the laser irradiation time, nature of the polyethylene materials and temperature.

  20. Electron beam welding of heat exchangers

    International Nuclear Information System (INIS)

    For a long time neither qualitative, nor quantitative criteria have been available that would have allowed choosing the most suitable welding techniques from the three stated below: 1) electron gun rotates relative to stationary tube; 2) electron beam is magnetically deviated relative to stationary tube; 3) permanent deviation magnet is rotated mechanically relative to stationary tube and gun. To our experience, the 2nd technique is most promising when welding 16x1.5 diameter stainless tubes. The e-b welds are vulnerable to root defects. With welding done in a movable manner, the root defect area will be found to locate in the tube plate body and, hence, the weldment, as a whole, will not be impaired

  1. Diffusion welding

    International Nuclear Information System (INIS)

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

  2. Torch Brazing Methods for Cast Iron QT500-7 and Its Influence on Performance of Brazed Joints%QT500—7铸铁火焰钎焊方法及其对接头性能的影响

    Institute of Scientific and Technical Information of China (English)

    王振波; 陈春焕

    2012-01-01

    Using B-Ag40CuZnCdNi alloy as filler metal, cast iron QT500 7 was connected by torch brazing. The effect of filler metal placement method and heating time on the shear strength of the brazed joints was studied by shear test and microstructure observation. The results showed that when sandwich method was used to place the filler metal, the joint was likely to cause welding defects, and the carrying capacity of the joint was lower than that of base metal. When capillary method was used in enough heating time, the filling process of the liquid metal had also played a role of cleaning the gap of brazing seam, which was helpful to get the joint with thin and straight brazing seam and less defects, so the shear strength had been improved, when the heating time was more than 5 min, the carrying capacity of the joint was higher than that of base metal, but it will be not as good as sandwich method if the heating time was insufficient.%以B-Ag40CuZnCdNi合金为钎料,采用火焰钎焊方法实现了QT500—7铸铁的连接。研究了“三明治”法和毛细法两种钎料放置方式及不同加热时间对钎焊接头抗剪强度的影响,并对连接界面的微观组织进行了分析。结果表明:用“三明治”法放置钎料时,接头容易产生焊接缺陷,接头的承载能力低于母材;用毛细法放置钎料时,在足够长的加热时间条件下,液态钎料的填缝过程同时具有清洁钎缝间隙的作用,有利于得到钎缝细小平直且缺陷少的接头,因此抗剪强度得到提高,加热时间大于5min时,接头承载能力高于母材,但加热时间不足时反而不如“三明治”法的施焊效果。

  3. Laser Seam welding method

    International Nuclear Information System (INIS)

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

  4. Friction Stir Spot Welding of Polymer Materials

    OpenAIRE

    Bekir ÇEVİK

    2014-01-01

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

  5. Sensor-guided robotic laser welding

    OpenAIRE

    Graaf, de, Joost

    2007-01-01

    Robotic laserwelding is a promising joining technique for welding of continuous seams in 3D products. High quality joints can be realised provided that the manipulation of the laser beam and the product tolerances meet strict criteria. The requirements for the positioning accuracy of the laser beamcan be fulfilled using seam-tracking sensors. This thesis describes how such sensors can be integrated in a robotic laser welding system for automatic teaching of the seam trajectory, but also to co...

  6. Improving fatigue performance of rail thermite welds

    OpenAIRE

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

    2010-01-01

    Rail transport development offers economic and ecological interests. Nevertheless, it requires heavy investments in rolling material and infrastructure. To be competitive, this transportation means must rely on safe and reliable infrastructure, which requires optimization of all implemented techniques and structure. Rail thermite (or aluminothermic) welding is widely used within the railway industry for in-track welding during re-rail and defect replacement. The process provides numerou...

  7. The non-destructive testing of transition welds

    International Nuclear Information System (INIS)

    This paper reviews C.E.G.B. experience of the NDT of transition butt welds joining tubes, pipes and thick plates. Pre-service inspection has been predominantly by radiography, while dye penetrants have been most frequently used for the in-service inspection of pipe to pipe welds. Some ultrasonic inspection has been performed with conventional techniques but its value was uncertain because of high attenuation and scatter in the weld metal. Nevertheless, ultrasonics is potentially the most useful technique, particularly for in-service inspection. Recent laboratory work is described which shows that the ultrasonic inspection of transition welds presents essentially the same problems as for austenitic welds of similar geometry, and that a limited sensitivity inspection is usually possible. The welding process used and the thickness of the weldment are identified as the most important factors governing the inspection capability. (author)

  8. Numerical and experiment study of residual stress and strain in multi-pass GMA welding

    Directory of Open Access Journals (Sweden)

    R.R. Chand

    2013-03-01

    Full Text Available Purpose: Recently, manufacturing industries have been concentrated on selection an optimal of welding parameter and condition that reduces the risk of mechanical failures on weld structures should be required in manufactory industry. In robotic GMA (Gas Metal Arc welding process, heat and mass inputs are coupled and transferred by the weld arc to the molten weld pool and by the molten metal that is being transferred to the weld pool. The amount and distribution of the input energy are basically controlled by the obvious and careful choices of welding process parameters in order to accomplish the optimal bead geometry and the desired mechanical properties of the quality weldment. The residual stress and welding deformation have the large impact on the failure of welded structures.Design/methodology/approach: To achieve the required precision for welded structures, it is required to predict the welding distortions at the early stages. Therefore, this study represented 2D Finite Element Method (FEM to predict residual stress and strain on thick SS400 steel metal plate.Findings: The experiment for Gas Metal Arc (GMA welding process is also performed with similar welding condition to validate the FE results. The simulated and experiment results provide good evidence that heat input is main dependent on the welding parameter and residual stress and distortions are mainly affected by amount on heat input during each weld-pass.Practical implications: This present study on based on the numerical analysis using ansys software, for a thick multi-pass GMA welding. A birth and death technique is employed to control the each weld pass welding.Originality/value: The developed 2D multi-pass model employs Goldak’s heat distribution, to simulate welding on SS400 steel butt-weld joint with a thickness of 16mm. moreover the numerical results are validated with experiment results.

  9. Weld repair of helium degraded reactor vessel material

    International Nuclear Information System (INIS)

    Welding methods for modification or repair of irradiated nuclear reactor vessels are being evaluated at the Savannah River Site. A low-penetration weld overlay technique has been developed to minimize the adverse effects of irradiation induced helium on the weldability of metals and alloys. This technique was successfully applied to Type 304 stainless steel test plates that contained 3 to 220 appm helium from tritium decay. Conventional welding practices caused significant cracking and degradation in the test plates. Optical microscopy of weld surfaces and cross sections showed that large surface toe cracks formed around conventional welds in the test plates but did not form around overlay welds. Scattered incipient underbead cracks (grain boundary separations) were associated with both conventional and overlay test welds. Tensile and bend tests were used to assess the effect of base metal helium content on the mechanical integrity of the low-penetration overlay welds. The axis of tensile specimens was perpendicular to the weld-base metal interface. Tensile specimens were machined after studs were resistance welded to overlay surfaces

  10. Effects of Conventional Welding and Laser Welding on the Tensile Strength, Ultimate Tensile Strength and Surface Characteristics of Two Cobalt–Chromium Alloys: A Comparative Study

    OpenAIRE

    Madhan Kumar, Seenivasan; Sethumadhava, Jayesh Raghavendra; Anand Kumar, Vaidyanathan; Manita, Grover

    2012-01-01

    The purpose of this study was to evaluate the efficacy of laser welding and conventional welding on the tensile strength and ultimate tensile strength of the cobalt–chromium alloy. Samples were prepared with two commercially available cobalt–chromium alloys (Wironium plus and Diadur alloy). The samples were sectioned and the broken fragments were joined using Conventional and Laser welding techniques. The welded joints were subjected to tensile and ultimate tensile strength testing; and scann...

  11. 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...

  12. Position welding using disk laser-GMA hybrid welding

    OpenAIRE

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

    2008-01-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2003-09-07

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

  14. PCA and Clustering based Weld Flaw Detection from Radiographic Weld Images

    Directory of Open Access Journals (Sweden)

    Dr.V. Vaithiyanathan

    2013-06-01

    Full Text Available Pattern recognition of weld defects can be done by partitioning the data points into clusters.The weld defect arises due to various types of adverse conditions and carelessness at the time of welding which leads to major disasters at the later stage. This paper proposes a method for detection of Burn Through, Slag Inclusion and Lack of Penetration weld defects in radiographic images which follow a specific pattern for each type. The image is preprocessed using Histogram equalization and segmented using Region growing methodology. The feature dimension reduction is performed using PCA, which is an unsupervised dimension reduction methodology which chooses the dimensions with the largest variance. K-Means clustering is used for clustering a cohesive group from a set of patterns after performing dimensionality reduction using Principal Component Analysis. The result of classification using this technique is providing a very accurate classification of weld defect.

  15. Cold metal transfer spot plug welding of AA6061-T6-to-galvanized steel for automotive applications

    Energy Technology Data Exchange (ETDEWEB)

    Cao, R., E-mail: caorui@lut.cn; Huang, Q.; Chen, J.H., E-mail: zchen@lut.cn; Wang, Pei-Chung

    2014-02-05

    Highlights: • Two Al-to-galvanized steel spot plug welding joints were studied by CMT method. • The optimum process variables for the two joints were gotten by orthogonal test. • Connection mechanism of the two joints were discussed. -- Abstract: In this study, cold metal transfer (CMT) spot plug joining of 1 mm thick Al AA6061-T6 to 1 mm thick galvanized steel (i.e., Q235) was studied. Welding variables were optimized for a plug weld in the center of a 25 mm overlap region with aluminum 4043 wire and 100% argon shielding gas. Microstructures and elemental distributions were characterized by scanning electron microscopy with energy dispersive X-ray spectrometer. Mechanical testing of CMT spot plug welded joints was conducted. It was found that it is feasible to join Al AA6061T6-to-galvanized steel by CMT spot plug welding method. The process variables for two joints with Al AA6061T6-to-galvanized mild steel and galvanized mild steel-to-Al AA6061T6 are optimized. The strength of CMT spot welded Al AA6061T6-to-galvanized mild steel is determined primarily by the strength and area of the brazed interface. While, the strength of the galvanized mild steel-to-Al AA6061T6 joint is mainly dependent upon the area of the weld metal.

  16. Cold metal transfer spot plug welding of AA6061-T6-to-galvanized steel for automotive applications

    International Nuclear Information System (INIS)

    Highlights: • Two Al-to-galvanized steel spot plug welding joints were studied by CMT method. • The optimum process variables for the two joints were gotten by orthogonal test. • Connection mechanism of the two joints were discussed. -- Abstract: In this study, cold metal transfer (CMT) spot plug joining of 1 mm thick Al AA6061-T6 to 1 mm thick galvanized steel (i.e., Q235) was studied. Welding variables were optimized for a plug weld in the center of a 25 mm overlap region with aluminum 4043 wire and 100% argon shielding gas. Microstructures and elemental distributions were characterized by scanning electron microscopy with energy dispersive X-ray spectrometer. Mechanical testing of CMT spot plug welded joints was conducted. It was found that it is feasible to join Al AA6061T6-to-galvanized steel by CMT spot plug welding method. The process variables for two joints with Al AA6061T6-to-galvanized mild steel and galvanized mild steel-to-Al AA6061T6 are optimized. The strength of CMT spot welded Al AA6061T6-to-galvanized mild steel is determined primarily by the strength and area of the brazed interface. While, the strength of the galvanized mild steel-to-Al AA6061T6 joint is mainly dependent upon the area of the weld metal

  17. Development of Alternative Technology to PWHT in Site Welding

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ho Jin; Lee, B. S.; Jang, J. S.; Kim, K. H.; Park, S. D.; Yoon, J. H.; Kim, M. C.; Kim, K. B.; Sung, K. W

    2007-04-15

    ASME Section IX added requirements for qualification when using temper bead welding in the 2004 edition. The temper bead welding techniques which can satisfy the requirements of the Code are needed to use them in the site repair welding. The optimized welding parameters can be obtained when controlling the process to supercritically-reheat and to subcritically-reheat the coarse grain region sequently. The microstructures of SCFGCG obtained from the Gleegle simulated specimens and those of post weld heat treated coarse grain region are compared. The obtained both microstructures showed almost similar patterns. mid bead deposition technique Suggested in this study has a technical concept that the mid beads are deposited between the deposited initial beads repeatedly in a bead layer, which gives a lot of reheating effects on brittle microstructure in HAZ. This newly suggested technique is considered to have more effective tempering effect than the conventional temper bead technique which has concept to deposit one type of beads in a bead layer. The suggested modeling in this study can simulate well the SMAW process. Hence this modeling was used in analyzing the more complicated welding process of multi-layer welding. The modeling was used to analyze the tempering effect on the microstructures of HAZ by considering the patterns of overlapping of the reheating regions under the consequently deposited beads. When considering the crack path in the ever-matched weld metal condition, the interface may have a resistance against the crack propagation. A182 filler and A625 filler were used to make the weld specimens which have different weld metal conditions. The crack directed toward the under-matched weld metal may propagate across the fusion line easier than that of the even-matched weld metal condition.

  18. Critical Issues for Producing UHTC-Brazed Joints: Wetting and Reactivity

    Science.gov (United States)

    Passerone, A.; Muolo, M. L.; Valenza, F.

    2016-08-01

    A brief survey is presented of the most important interaction phenomena occurring at the solid-liquid interfaces in metal-ceramic systems at high temperatures, with special attention to the most recent developments concerning wetting and joining transition metals diborides. These phenomena are described and discussed from both the experimental and theoretical points of view in relation to joining ceramic and metal-ceramic systems by means of processes in the presence of a liquid phase (brazing, TLPB etc.). It is shown that wetting and the formation of interfacial dissolution regions are the results of the competition between different phenomena: dissolution of the ceramic in the liquid phase, reaction and formation of new phases at the solid-liquid interface, and drop spreading along the substrate surface. We emphasize the role of phase diagrams to support both the design of the experiments and the choice of active alloying elements, and to interpret the evolution of the system in relation to temperature and composition. In this respect, the sessile-drop technique has been shown to be helpful in assessing critical points of newly calculated phase diagrams. These studies are essential for the design of joining processes, for the creation of composite materials, and are of a particular relevance when applied to UHTC materials.

  19. Automatic welding technologies for long-distance pipelines by use of all-position self-shielded flux cored wires

    Directory of Open Access Journals (Sweden)

    Zeng Huilin

    2014-10-01

    Full Text Available In order to realize the automatic welding of pipes in a complex operation environment, an automatic welding system has been developed by use of all-position self-shielded flux cored wires due to their advantages, such as all-position weldability, good detachability, arc's stability, low incomplete fusion, no need for welding protective gas or protection against wind when the wind speed is < 8 m/s. This system consists of a welding carrier, a guide rail, an auto-control system, a welding source, a wire feeder, and so on. Welding experiments with this system were performed on the X-80 pipeline steel to determine proper welding parameters. The welding technique comprises root welding, filling welding and cover welding and their welding parameters were obtained from experimental analysis. On this basis, the mechanical properties tests were carried out on welded joints in this case. Results show that this system can help improve the continuity and stability of the whole welding process and the welded joints' inherent quality, appearance shape, and mechanical performance can all meet the welding criteria for X-80 pipeline steel; with no need for windbreak fences, the overall welding cost will be sharply reduced. Meanwhile, more positive proposals were presented herein for the further research and development of this self-shielded flux core wires.

  20. Characteristics of Welding Fumes

    OpenAIRE

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

    1981-01-01

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