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.


    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


    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. Preliminary study on pressure brazing and diffusion welding of Nb-1Zr to Inconel 718 (United States)

    Moore, T. J.


    Future space power systems may include Nb-1Zr/Inconel 718 dissimilar metal joints for operation at 1000 K for 60,000 h. The serviceability of pressure-brazed and diffusion-welded joints was investigated. Ni-based metallic glass foil filler metals were used for brazing. Ni and Fe foils were used as diffusion welding inter-layers. Joint soundness was determined by metallographic examination in the as-brazed and as-welded condition, after aging at 1000 K, and after thermal cycling. Brazed joints thermally cycled in the as-brazed condition and diffusion-welded joints were unsatisfactory because of cracking problems. Brazed joints may meet the service requirements if the joints are aged at 1000 K prior to thermal cycling.


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    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.

  5. 78 FR 53159 - Standard for Welding, Cutting, and Brazing; Extension of the Office of Management and Budget's... (United States)


    ... Occupational Safety and Health Administration Standard for Welding, Cutting, and Brazing; Extension of the..., Cutting, and Brazing (29 CFR Part 1910, Subpart Q). The information collected is used by employers and workers whenever welding, cutting, and brazing are performed. The purpose of the information is to...

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

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    Winiowski A.


    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.

  7. Investigation of welding and brazing of molybdenum and TZM alloy tubes (United States)

    Lundblad, Wayne E.


    This effort involved investigating the welding and brazing techniques of molybdenum tubes to be used as cartridges in the crystal growth cartridge. Information is given in the form of charts and photomicrographs. It was found that the recrystallization temperature of molybdenum can be increased by alloying it with 0.5 percent titanium and 0.1 percent zirconium. Recrystallization temperatures for this alloy, known as TZM, become significant around 2500 F. A series of microhardness tests were run on samples of virgin and heat soaked TZM. The test results are given in tabular form. It was concluded that powder metallurgy TZM may be an acceptable cartridge material.

  8. Brazing handbook

    CERN Document Server

    American Welding Society


    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.

  9. Brazing

    CERN Document Server

    Schwartz, Mel M


    Text provides information needed to braze materials that will be used in the 21st century. Revised to include lessons learned on tooling, design, materials, atmospheres, processing, and equipment. For brazing technologists and engineers.

  10. 75 FR 52037 - Welding, Cutting and Brazing Standard; Extension of the Office of Management and Budget's (OMB... (United States)


    ... 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 CFR part 1910, subpart Q). The information collected is used by employers and workers whenever...

  11. Corrosion Behavior of MIG Brazed and MIG Welded Joints of Automotive DP600-GI Steel Sheet (United States)

    Basak, Sushovan; Das, Hrishikesh; Pal, Tapan Kumar; Shome, Mahadev


    Galvanized dual-phase steel sheets are extensively used by the auto industry for their corrosion resistance property. Welding by the metal inert gas (MIG) process causes degradation of the steel in the vicinity of the joint due to excessive zinc evaporation. In order to minimize Zn loss, the MIG brazing process has been tried out in lap joint configuration over a heat input range of 136-204 J mm-1. The amount of zinc loss, intermetallic formation and corrosion properties in the joint area has been evaluated for both MIG brazing and MIG welding. Corrosion rate of 21 mm year-1 has been reduced to 2 mm year-1 by adopting MIGB in place MIGW. Impedance study has shown that the corrosion mechanism in base metal, MIG brazed and MIG welded joints is dominated by charge transfer, diffusion and mixed mode control processes, respectively.

  12. 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


    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.

  13. Evaluation of Laser Braze-welded Dissimilar Al-Cu Joints (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.

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

    Directory of Open Access Journals (Sweden)

    J. Matusiak


    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.

  15. SHADOW: a new welding technique (United States)

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


    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.

  16. Mechanical characteristics of laser braze-welded aluminium-copper connections (United States)

    Solchenbach, Tobias; Plapper, Peter


    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.

  17. The effects of fillet formation on the strength of braze pressure welded joint with high frequency induction heating

    Energy Technology Data Exchange (ETDEWEB)

    Suzumura, A.; Inagaki, Y.; Ikeshoji, T.T.; Yamazaki, T. [Graduate School of Tokyo, Tokyo (Japan)


    Braze Pressure Welding (BPW) with high frequency induction heating had been invented as the new joining method for bonding general steel pipes for on-site piping without danger of fire and the dispersion in joint properties due to welder's skill. In the BPW, brazing filler is interlaid between the mating surfaces to be joined. The filler melts by heating up to joining temperature, then the welding pressure discharges it from the joining interface. At the same time, the base metals are pressure-welded to each other, and that the discharged liquid filler forms fillets around the joining area. The fillets have the effects both on relaxing the stress concentration at the joint and on increasing the joining area, which contributes to the strengthening of joint. And the pressure is comparatively low, so the deformation of joint is little. In this paper, in order to investigate the effects of fillet on strengthening the joint, the stress state around the joint area and the degree of the effect of stress concentration relaxation were analyzed by finite element analysis. So it was revealed that the fillets reduced the stress concentration and separated the maximum stress site from the edge of the joining interface. Experimentally, the fillet formation was confirmed around the BPW joining area and that BPW joint had the superior tensile strength to brazed or pressure-welded joints by tensile test of joints. (orig.)

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

  19. Microstructure characteristics and mechanical property of aluminum alloy/stainless steel lap joints fabricated by MIG welding-brazing process

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Hongtao, E-mail: [School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209 (China); Liu Jiakun [School of Materials Science and Engineering, Harbin Institute of Technology at Weihai, Weihai 264209 (China)


    Highlights: {yields} Wrought aluminum and stainless steel was joined with welding-brazing process. {yields} Effect of different layers on spreadability of molten filler metal was examined. {yields} Mechanical property of the joints with different heat inputs was investigated. {yields} Microstructure of the joints were also studied by OM, SEM and TEM. {yields} Phase composition was ascertained by diffraction spot and XRD analysis. - Abstract: Lap joints of aluminum alloy 2B50 and stainless steel 1Cr18Ni9Ti were welded by MIG welding-brazing method with 4043 Al-Si filler metal. The effect of aluminizing coating and galvanized zinc coating on fusion metal spreadability were studied. The aluminized coating had limited effect to promote weld surface appearance and obvious micro-cracks were found between the compound layer and the steel side. The fracture in tensile tests occurred at the interfacial layer of the weld with a low tensile strength about 60 MPa. Joints between aluminum alloy and galvanized steel had good surface appearances and the intermetallic compound in fusion zone region close to joint interface was Al{sub 4.5}FeSi. The thickness of the intermetallic compound layer varied from about 5 {mu}m to 15 {mu}m depending on the heat input and the highest tensile strength of lap joint could reached 193.6 MPa when the heat input is 0.846 KJ/cm.

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

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    Ms. Deepika Harwani


    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.

  1. Techniques for laser welding polymeric devices. (United States)

    Jones, I A


    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.

  2. 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)


    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

  3. 49 CFR 178.55 - Specification 4B240ET welded or brazed cylinders. (United States)


    ... integral formed heads or bases must be subjected to a normalizing operation. Normalizing and brazing... strain measurement, the initial strain must be set while the specimen is under a stress of 12,000 psi...

  4. Secondary ledeburite formation during various welding techniques

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    Tonkovič M.P.


    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.

  5. Innovative Tools Advance Revolutionary Weld Technique (United States)


    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

  6. 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


    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.

  7. 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


    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.

  8. Low activation brazing materials and techniques for SiC f/SiC composites (United States)

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


    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.

  9. Graphite-to-304SS Braze Joining by Active Metal-Brazing Technique: Improvement of Mechanical Properties (United States)

    Ray, Ajoy K.; Kar, Abhijit; Kori, S. A.; Pathak, L. C.; Sonnad, A. N.


    In the present investigation, an attempt has been made to improve the mechanical strength of graphite-stainless steel-brazed joint. Due to high capillary action, the liquid filler alloy usually tends to percolate into the pores of graphite causing severe stress in the graphite near the joint interface resulting in poor joint strength of 10-15 MPa. In the present investigation, a thin coating of SiC was applied on graphite before the joining process to avoid the penetration of liquid filler alloy into the pores of the graphite. Active filler alloy Ag-Cu-Ti was used to braze the substrates. The brazing was carried out at 850, 900, 950, and 1000 °C. The characterization of the interfaces of the brazed joints was carried out using scanning electron microscopy attached with energy dispersive spectroscopy and x-ray diffraction analysis. From the correlation between the microstructural and mechanical properties, shear strength of approximately 35 MPa for graphite-304SS-brazed joint produced at 900 °C was demonstrated. After the shear tests, the fracture surfaces were analyzed by SEM-EDS.

  10. Dissolution behavior of Cu in Cu-Ag and Cu-P brazing alloys using weld brazing%溶解钎焊时Cu在Cu-Ag及Cu-P合金钎料中的溶解行为

    Institute of Scientific and Technical Information of China (English)

    李一楠; 王长文; 彭子龙; 闫久春; 刘雪松


    研究溶解钎焊条件下母材Cu在Cu-Ag及Cu-P合金钎料中的溶解行为.测量了在800~920℃的温度范围内铜箔在Cu-P和Cu-Ag合金中的溶解厚度.推导并计算出Cu在这两种合金钎料中的溶解速度常数存在如下关系:kCu-p(T)=10kCu-A(T).结果表明,采用溶解钎焊工艺时在相同条件下液态Cu-P合金对母材Cu的溶解量大于Cu-Ag合金的.由于溶解钎焊工艺在一个热循环内具有反应时间短和温度变化快的特点,因此Cu在液态钎料中快的溶解反应速度是实现溶解钎焊的根本原因.同时,P元素与Ag元素相比具有加速溶解母材的作用,是实现溶解钎焊必不可少的合金元素.研究了合金元素的添加对焊接接头力学性能的影响,提出了获得良好力学性能的钎料成分设计原则.%The dissolution behavior of base metal Cu in the Cu-Ag and Cu-P brazing alloys using weld brazing was researched.The thickness loss of Cu foil in contact with Cu-P and Cu-Ag alloys at 800-920 ℃ was measured.And the dissolution rate constants in both alloys were calculated as the following relation:kcu-p(T)=1 0kCu.Ag(T),which explains the special phenomenon that the dissolving amount of copper in Cu-P liquid alloys is larger than that in Cu-Ag alloys under the same condition.As weld brazing has its own characteristics of short reaction time and quick temperature variation in one thermal cycle,the quick dissolution rate of copper in filler metals is the main reason to achieve weld brazing.It can be concluded that element P is indispensable in filler metals compared with element Ag as the function of accelerating dissolution during weld brazing.Finally,the influences of the addition of alloy element on mechanical performance of the welding joints were studied and the design principles of filler metals for weld brazing were proposed to achieve good mechanical performance.

  11. 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


    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.

  12. Airborne fibre levels associated with the use of MMMF brazing mats during welding operations. (United States)

    Waterman, L S; Purnell, C J; Anderson, P W


    In 1985 the Health and Safety Executive set a gravimetric Control Limit for airborne Man-Made Mineral Fibre and in 1987 a respirable fibre number Recommended Limit for Superfine MMMF. A limited investigation was carried out of the use of glass and ceramic fibre products used as protection against welding 'batter' and oxyacetylene welding flame. Airborne fibre levels are compared with the Occupational Exposure Limits.

  13. Influence of laser power on microstructure and mechanical properties of laser welded-brazed Mg to Ni coated Ti alloys (United States)

    Tan, Caiwang; Lu, Qingshuang; Chen, Bo; Song, Xiaoguo; Li, Liqun; Feng, Jicai; Wang, Yang


    AZ31B Magnesium (Mg) and Ti-6Al-4V titanium (Ti) alloys with Ni coating were joined by laser welding-brazing process using AZ92 Mg based filler. The influence of laser power on microstructure and mechanical properties were investigated. Ni coating was found to significantly promote good wetting-spreading ability of molten filler on the Ti sheet. Acceptable joints without obvious defects were obtained within a relatively wide processing window. In the process metallurgical bonding was achieved by the formation of Ti3Al phase at direct irradiation zone and Al-Ni phase followed by a layer of Mg-Al-Ni ternary compound adjacent to the fusion zone at the intermediate zone. The thickness of reaction layers increased slowly with the increasing laser power. The tensile-shear test indicated that joints produced at the laser power of 1300 W reached 2387 N fracture load, representing 88.5% joint efficiency with respect to the Mg base metal. The corresponding failure occurred in the fusion zone of the Mg base metal, while joints fractured at the interface at lower/higher laser power due to the crack or excessive intermetallic compound (IMC) formation along the interface.

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

    Energy Technology Data Exchange (ETDEWEB)

    Munez, C.J., E-mail: [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)


    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.

  15. Friction Buttering: A New Technique for Dissimilar Welding (United States)

    Karthik, G. M.; Mastanaiah, P.; Janaki Ram, G. D.; Kottada, Ravi Sankar


    This work offers a fresh perspective on buttering, a technique often considered for fusion welding of dissimilar metals. For the first time, buttering was attempted in solid state using friction deposition. Using this new "friction buttering" technique, fusion welding of two different dissimilar metal pairs (austenitic stainless steel/borated stainless steel and Al-Cu-Mg/Al-Zn-Mg-Cu) was successfully demonstrated. The results show that friction buttering can simplify a tough dissimilar welding problem into a routine fusion welding task.

  16. Soldadura (Welding). Spanish Translations for Welding. (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…

  17. Advances in brazing science, technology and applications

    CERN Document Server


    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...

  18. Vacuum Brazing of Accelerator Components (United States)

    Singh, Rajvir; Pant, K. K.; Lal, Shankar; Yadav, D. P.; Garg, S. R.; Raghuvanshi, V. K.; Mundra, G.


    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.

  19. Effect of welding techniques on microstructure and mechanical properties of aluminium-lithium alloy welds

    Energy Technology Data Exchange (ETDEWEB)

    Madhusudhan Reddy, G.; Gokhale, A.A.; Saxena, V.K. [Defence Metallurgical Research Lab., Hyderabad (India); Prasad Rao, K.


    The tensile properties and fatigue crack growth behaviour of sheets of an Al-1.9Li-1.8Cu-1.0 Mg-0.1Zr alloy welded under different conditions were evaluated. The basic welding technique was constant current (CC) gas tungsten arc (GTA) welding. Two modifications viz. pulsed current (PC) and magnetic arc oscillation (AO) were introduced to study effects on microstructure and properties. Both PC and AO resulted in microstructural refinement in the fusion zone. The tensile residual stresses present in CC welds reduced when either PC or AO welding was used. The tensile strength and ductility increased, and fatigue crack growth rates lowered when PC or AO conditions replaced CC welding. (orig.)

  20. 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


    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.

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

    Directory of Open Access Journals (Sweden)

    B. Karthikeyan


    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.

  2. RFQ Vacuum brazing at CERN

    CERN Document Server

    Mathot, S


    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...

  3. Laser Brazing of High Temperature Braze Alloy (United States)

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


    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

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

    Directory of Open Access Journals (Sweden)

    C. Fornaini


    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. Advanced Welding Concepts (United States)

    Ding, Robert J.


    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.

  6. Induction brazing manual (United States)


    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.

  7. Laser transmission welding of Clearweld-coated polyethylene glycol terephthalate by incremental scanning technique (United States)

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


    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.

  8. 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


    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.

  9. Induction Brazing

    DEFF Research Database (Denmark)

    Henningsen, Poul

    . The method has proven to give successful results in brazing tube-plate joints of copper-brass, copper-stainless steel, stainless steel-brass, and stainless steel-stainless steel. A new design of an adjustable flux concentrator for induction heating tube-to-plate joints is proposed and tested on a variety......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...

  10. 78 FR 75947 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Welding... (United States)


    ...; 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...

  11. 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


    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.

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

    Directory of Open Access Journals (Sweden)

    Pravin Kumar Singh


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

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

    DEFF Research Database (Denmark)

    Bay, Niels


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

  14. 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


    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

  15. 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


    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.

  16. 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


    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 ...

  17. 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


    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.

  18. 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


    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

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

    Directory of Open Access Journals (Sweden)

    Liming Liu


    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.

  20. 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)


    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.

  1. Development of laser welding techniques for vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  2. 29 CFR 1910.255 - Resistance welding. (United States)


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

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

    NARCIS (Netherlands)

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


    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

  4. Characterization of 2.25Cr1Mo welded ferritic steel plate by using diffractometric and ultrasonic techniques

    Energy Technology Data Exchange (ETDEWEB)

    Cernuschi, F.; Ghia, S. [Ente Nazionale per l`Energia Elettrica, Milan (Italy); Albertini, G.; Ceretti, M.; Rustichelli, F. [Ancona Univ. (Italy). Ist. di Fisica Medica; Castelnuovo, A.; Depero, L. [Univ. degli studi, Brescia.Fac. di ingegneria, dip. di ingegneria meccanica (Italy); Giamboni, S.; Gori, M. [Centro Elettrotecnico Sperimentale Italiano (CESI), Milan (Italy)


    Four different techniques (X-ray and neutron diffraction, ultrasonic birefringence and incremental hole drilling method) were applied for evaluating residual stress in a butt-welded ferritic steel palte. Measurements were carried out both before and after welding. Effects of post-welding heat treatment is also considered. A comparison between results obtained by using four different techniques is done.

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

    Energy Technology Data Exchange (ETDEWEB)

    Livingstone, S., E-mail: [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)


    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.

  6. A Study of Friction Stir Welded 2195 Al-Li Alloy by the Scanning Reference Electrode Technique (United States)

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


    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.

  7. 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


    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.

  8. 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:; 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)


    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.

  9. Subtask 12B2: Development of laser welding techniques for vanadium alloys

    Energy Technology Data Exchange (ETDEWEB)

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


    The development of techniques for joining vanadium alloys will be required for the construction of fusion devices utilizing the desirable properties of these alloys. The primary objective of this program is to develop of laser welding techniques for vanadium alloys, particularly for the manufacture of welded materials testing specimens. Laser welding is potentially advantageous because of its flexibility and the reduced amount of material effected by the weld. Lasers do not require a vacuum (as does electron beam welders) and the welds they produce have large depth-to-width ratios. Results of scoping tests using a small, pulsed laser (50 joule, 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. Successful bead-on-plate welds have been made to depths of about 4-mm using a 6 kW continuous CO{sub 2} laser with argon purging. 2 figs.

  10. Corrosion Behavior of Brazed Zinc-Coated Structured Sheet Metal

    Directory of Open Access Journals (Sweden)

    A. Nikitin


    Full Text Available Arc brazing has, in comparison to arc welding, the advantage of less heat input while joining galvanized sheet metals. The evaporation of zinc is reduced in the areas adjacent to the joint and improved corrosion protection is achieved. In the automotive industry, lightweight design is a key technology against the background of the weight and environment protection. Structured sheet metals have higher stiffness compared to typical automobile sheet metals and therefore they can play an important role in lightweight structures. In the present paper, three arc brazing variants of galvanized structured sheet metals were validated in terms of the corrosion behavior. The standard gas metal arc brazing, the pulsed arc brazing, and the cold metal transfer (CMT® in combination with a pulsed cycle were investigated. In experimental climate change tests, the influence of the brazing processes on the corrosion behavior of galvanized structured sheet metals was investigated. After that, the corrosion behavior of brazed structured and flat sheet metals was compared. Because of the selected lap joint, the valuation of damage between sheet metals was conducted. The pulsed CMT brazing has been derived from the results as the best brazing method for the joining process of galvanized structured sheet metals.

  11. Research and Application on Using Natural Gas Instead of Liquefied Petroleum Gas in Braze Welding%用天然气代替液化石油气钎焊研究与应用

    Institute of Scientific and Technical Information of China (English)

    邓映波; 梁绍吉; 陈国强; 潘耀权


    According to the energy structure situation of flame machining in China, this paper puts forward the corre-sponding technique transformation for the brazing equipment using liquefied petroleum gas. It realizes using the natural gas instead of liquefied petroleum gas. The practice shows this technique has the characteristics of low cost and conve-nient operation. The personal safety and brazing quality is as good as using the liquefied petroleum gas, and the price is lower than it.%本文针对我国火焰加工的能源结构状况,提出对液化石油气钎焊设备进行相应的技术改造, 实现用天然气代替液化石油气.实践表明, 天然气代替液化石油气,其技术改造成本低,简便易行,工人作业的安全性和钎焊质量与液化石油气相当,但价格远低于液化石油气.

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

  13. 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:, E-mail: [Universidade Nova de Lisboa, UNIDEMI, Departamento de Engenharia Mecanica e Industrial, Faculdade de Ciencias e Tecnologia, Caparica (Portugal); Vilaca, P., E-mail: [Aalto Univ., Dept. of Engineering Design and Production, School of Engineering, Aalto (Finland); Miranda, R., E-mail: [Universidade Nova de Lisboa, UNIDEMI, Departamento de Engenharia Mecanica e Industrial, Faculdade de Ciencias e Tecnologia, Caparica (Portugal)


    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)

  14. 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


    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

  15. 75 FR 74083 - Agency Information Collection Activities; Submission for OMB Review; Comment Request; Welding... (United States)


    ...; 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) for... inspection of resistance welding equipment be made by qualified maintenance personnel and that...

  16. 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


    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.

  17. Reliable Welding of HSLA Steels by Square Wave Pulsing Using an Advanced Sensing (EDAP) Technique. (United States)


    situation is the result of welding on A710 steel . (A similar effect on welding on HY80 ?) The following is offered by Woods and Milner (Ref. 12): "The...AD-R69 762 RELIABLE MELDING OF HSLA STEELS BY SQUARE MAVE PULSING 1/2 USING AN ADV NCED.. (U) APPLIED FUSION TECHNOLOGIES INC FORT COLLINS CO C...6 p . 0 Report 0001 AZ AD-A 168 762 I "RELIABLE WELDING OF HSLA STEELS BY SQUARE WAVE PULSING USING AN ADVANCED SENSING (EDAP) TECHNIQUE- Preliminary

  18. Welding. (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. Ultrapulse welding: A new joining technique. [for automotive industry (United States)

    Anderson, D. G.


    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.

  20. 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


    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.

  1. Advanced Techniques for In-Situ Monitoring of Phase Transformations During Welding Using Synchrotron-Based X-Ray Diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Elmer, J W; Palmer, T A; Zhang, W; DebRoy, T


    Understanding the evolution of microstructure in welds is an important goal of welding research because of the strong correlation between weld microstructure and weld properties. To achieve this goal it is important to develop a quantitative measure of phase transformations encountered during welding in order to ultimately develop methods for predicting weld microstructures from the characteristics of the welding process. To aid in this effort, synchrotron radiation methods have been developed at Lawrence Livermore National Laboratory (LLNL) for direct observation of microstructure evolution during welding. Using intense, highly collimated synchrotron radiation, the atomic structure of the weld heat affected and fusion zones can be probed in real time. Two synchrotron-based techniques, known as spatially resolved (SRXRD) and time resolved (TRXRD) x-ray diffraction, have been developed for these investigations. These techniques have now been used to investigate welding induced phase transformations in titanium alloys, low alloy steels, and stainless steel alloys. This paper will provide a brief overview of these methods and will discuss microstructural evolution during the welding of low carbon (AISI 1005) and medium carbon (AISI 1045) steels where the different levels of carbon influence the evolution of microstructures during welding.

  2. 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


    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.

  3. Microstructure of arc brazed and diffusion bonded joints of stainless steel and SiC reinforced aluminum matrix composite (United States)

    Elßner, M.; Weis, S.; Grund, T.; Wagner, G.; Habisch, S.; Mayr, P.


    Joint interfaces of aluminum and stainless steel often exhibit intermetallics of Al-Fe, which limit the joint strength. In order to reduce these brittle phases in joints of aluminum matrix composites (AMC) and stainless steel, diffusion bonding and arc brazing are used. Due to the absence of a liquid phase, diffusion welding can reduce the formation of these critical in- termetallics. For this joining technique, the influence of surface treatments and adjusted time- temperature-surface-pressure-regimes is investigated. On the other hand, arc brazing offers the advantage to combine a localized heat input with the application of a low melting filler and was conducted using the system Al-Ag-Cu. Results of the joining tests using both approaches are described and discussed with regard to the microstructure of the joints and the interfaces.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, Adam C., E-mail:; Fisher, Jay L., E-mail: [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)


    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.

  5. Development of a pseudo phased array technique using EMATs for DM weld testing (United States)

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


    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.

  6. Brazing titanium structures. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Pressly, H.B.


    A vacuum furnace brazing process using Ag-5A1-0.5Mn brazing alloy has been developed for joining titanium alloy Ti-6Al-4V structures. Lap-shear strengths of the braze joints and the effects of the brazing thermal cycle on the tensile and bending properties of mill-annealed Ti-6Al-4V alloy sheet are reported. Nondestructive test methods were evaluated for detecting defects in these braze joints.

  7. Brazing development and interfacial metallurgy study of tungsten and copper joints with eutectic gold copper brazing alloy

    Energy Technology Data Exchange (ETDEWEB)

    Easton, David, E-mail: [University of Strathclyde, Department of Mechanical Engineering, Glasgow G1 1XJ (United Kingdom); Zhang, Yuxuan; Wood, James; Galloway, Alexander; Robbie, Mikael Olsson [University of Strathclyde, Department of Mechanical Engineering, Glasgow G1 1XJ (United Kingdom); Hardie, Christopher [Culham Centre for Fusion Energy CCFE, Culham Science Centre, Oxfordshire OX14 3DB (United Kingdom)


    Highlights: • A eutectic gold–copper brazing alloy has been successfully used to produce a highly wetted brazed joint between tungsten and copper. • Relevant materials for fusion applications. • Mechanical testing of W–AuCu–Cu soon to be performed. - Abstract: Current proposals for the divertor component of a thermonuclear fusion reactor include tungsten and copper as potentially suitable materials. This paper presents the procedures developed for the successful brazing of tungsten to oxygen free high conductivity (OFHC) copper using a fusion appropriate gold based brazing alloy, Orobraze 890 (Au80Cu20). The objectives were to develop preparation techniques and brazing procedures in order to produce a repeatable, defect free butt joint for tungsten to copper. Multiple brazing methods were utilised and brazing parameters altered to achieve the best joint possible. Successful and unsuccessful brazed specimens were sectioned and analysed using optical and scanning electron microscopy, EDX analysis and ultrasonic evaluation. It has been determined that brazing with Au80Cu20 has the potential to be a suitable joining method for a tungsten to copper joint.

  8. Impact of different welding techniques on biological effect markers in exhaled breath condensate of 58 mild steel welders. (United States)

    Hoffmeyer, Frank; Raulf-Heimsoth, Monika; Lehnert, Martin; Kendzia, Benjamin; Bernard, Sabine; Berresheim, Hans; Düser, Maria; Henry, Jana; Weiss, Tobias; Koch, Holger M; Pesch, Beate; Brüning, Thomas


    Total mass and composition of welding fumes are predominantly dependent on the welding technique and welding wire applied. The objective of this study was to investigate the impact of welding techniques on biological effect markers in exhaled breath condensate (EBC) of 58 healthy welders. The welding techniques applied were gas metal arc welding with solid wire (GMAW) (n=29) or flux cored wire (FCAW) (n=29). Welding fume particles were collected with personal samplers in the breathing zone inside the helmets. Levels of leukotriene B(4) (LTB(4)), prostaglandin E(2) (PGE(2)), and 8-isoprostane (8-iso-PGF(2α)) were measured with immunoassay kits and the EBC pH was measured after deaeration. Significantly higher 8-iso-PGF(2α) concentrations and a less acid pH were detected in EBC of welders using the FCAW than in EBC of welders using the GMAW technique. The lowest LTB(4) concentrations were measured in nonsmoking welders applying a solid wire. No significant influences were found in EBC concentrations of PGE(2) based upon smoking status or type of welding technique. This study suggests an enhanced irritative effect in the lower airways of mild steel welders due to the application of FCAW compared to GMAW, most likely associated with a higher emission of welding fumes.

  9. 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


    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.

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

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


    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.

  11. 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


    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.

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

    Institute of Scientific and Technical Information of China (English)


    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.

  13. Evaluation on defect in the weld of stainless steel materials using nondestructive technique

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jin Kyung, E-mail: [Department of Mechanical Engineering, Dongeui University, Eomgwangno 176, Busanjingu, Busan 614-714 (Korea, Republic of); Bae, Dong Su [Department of Advanced Materials Engineering, Dongeui University, Eomgwangno 176, Busanjingu, Busan 614-714 (Korea, Republic of); Lee, Sang Pill [Department of Mechanical Engineering, Dongeui University, Eomgwangno 176, Busanjingu, Busan 614-714 (Korea, Republic of); Lee, Joon Hyun [School of Mechanical Engineering, Pusan National University, Busandaehakro 63beongil, Geumjeonggu, Busan 609-735 (Korea, Republic of)


    The objective of this study is to evaluate the elastic wave's characteristic on the crack in the weld of stainless steel materials using guided wave and acoustic emission, nondestructive tests. The stainless steel is expected as candidate of structural piping material under high temperature condition in nuclear fusion instrument, and a tungsten inert gas (TIG) weld technique was applied for making its jointing. The defect size of 20 mm was induced in the weld material. The guided wave, one of elastic waves, can propagate through very long pipe, and easily change to lots of modes by the defects in the structure. By analyzing the relationship between the mode conversion and the defects we can evaluate existing of the defects in weld material. In present study Nd-YAG laser was used to excite the guided wave by non-contact method, and AE technique was also used to clarify the mode conversion of guided wave by defect because lots of AE parameters of energy, count and amplitude can give more chances for analysis of mode conversion. The optimal AE parameters for the evaluation of the defects in weld zone using laser guided wave were derived.

  14. Characterization of Nitinol Laser-Weld Joints by Nondestructive Testing (United States)

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


    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.

  15. Thermal response of ceramic components during electron beam brazing

    Energy Technology Data Exchange (ETDEWEB)

    Voth, T.E.; Gianoulakis, S.E.; Halbleib, J.A.


    Ceramics are being used increasingly in applications where high temperatures are encountered such as automobile and gas turbine engines. However, the use of ceramics is limited by a lack of methods capable of producing strong, high temperature joints. This is because most ceramic-ceramic joining techniques, such as brazing, require that the entire assembly be exposed to high temperatures in order to assure that the braze material melts. Alternatively, localized heating using high energy electron beams may be used to selectively heat the braze material. In this work, high energy electron beam brazing of a ceramic part is modeled numerically. The part considered consists of a ceramic cylinder and disk between which is sandwiched an annular washer of braze material. An electron beam impinges on the disk, melting the braze metal. The resulting coupled electron and thermal transport equations are solved using Monte Carlo and finite element techniques. Results indicate that increased electron beam current decreases time to melt as well as required cooling time. Vacuum furnace brazing was also simulated and predicted results indicate increased processing times relative to electron beam brazing.

  16. 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;


    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...


    Directory of Open Access Journals (Sweden)

    F. I. Panteleenko


    Full Text Available The technique of metalware condition estimation is worked out by authors. Questions of its adaptation to the quality assurance of restored and strengthened details and tools with the wearresistant coatings deposited are discussed. Magnetic and durometrie methods of nondestructive control used in order to estimate the exploitation reliability of details with welded coatings. Efficiency of this methods is confirmed.

  18. Thin-film diffusion brazing of titanium alloys (United States)

    Mikus, E. B.


    A thin film diffusion brazing technique for joining titanium alloys by use of a Cu intermediate is described. The method has been characterized in terms of static and dynamic mechanical properties on Ti-6Al-4V alloy. These include tensile, fracture toughness, stress corrosion, shear, corrosion fatigue, mechanical fatigue and acoustic fatigue. Most of the properties of titanium joints formed by thin film diffusion brazing are equal or exceed base metal properties. The advantages of thin film diffusion brazing over solid state diffusion bonding and brazing with conventional braze alloys are discussed. The producibility advantages of this process over others provide the potential for producing high efficiency joints in structural components of titanium alloys for the minimum cost.

  19. Plasma arc brazing - a low energy joining technology for steel sheets; Plasmalichtbogenloeten - eine energiearme Fuegetechnik fuer Feinblechwerkstoffe

    Energy Technology Data Exchange (ETDEWEB)

    Bouaifi, B.; Draugelates, U.; Helmich, A.; Ouaissa, B. [TU Clausthal, Clausthal-Zellerfeld (Germany)


    Mild and high strength steel sheets are comparatively difficult to weld. The heat input in the case of conventional welding processes is too high, so that plasma brazing is an attractive alternative and complementary joining process. One characteristic of the process is the independent input of energy and filler material. In addition, the process is practically spatter-free. Plasma brazing reduces joint and panel distortion and is tolerant to surface contamination and metallic surface coatings. The brazed seams are aesthetic in appearance and clear good mechanical properties. (orig.)

  20. Design and experimental research on vacuum packaging of MEMS gyroscope based on braze welding%基于钎焊的MEMS陀螺真空封装设计与实验研究

    Institute of Scientific and Technical Information of China (English)

    赵小慧; 周斌; 陈志勇; 张嵘


    Vacuum package is an effective method to reduce the vibration damping, and improve the quality factor,and to improve the performance of silicon MEMS linear vibratory gyroscopes. A design proposal of vacuum packaging of gyroscopes based on braze welding is introduced. The proposal is executed without using any getter,so the controllable vacuum degree can be realized. Theoretical calculation shows that, this packaging can maintain vacuum degree below 1 Pa. The test on vacuum packaged gyroscope shows that the Q factor of gyroscope' s driving mode is 1 700,which meets the design goals of 1500. After test for 186 d ,the gyro' s Q factor remains unchanged, which verifies the reliability of this vacuum packaging scheme.%对于线振动硅微机电系统(MEMS)陀螺,真空封装是减小其振动阻尼、提高振动品质因数,进而提高性能的一种有效的措施.设计了一种基于钎焊的硅MEMS陀螺真空封装方案,该方案因不采用吸气剂,故可实现真空度可控.理论计算表明:该封装形式可以保持1 Pa以下的真空度;经过对真空封装后的陀螺实验测试结果表明:设计的陀螺驱动轴品质因数为1500,实际封装后的陀螺驱动轴品质因数为1700,满足真空度设计目标.经过对封装后的陀螺品质因数进行186d的跟踪测试,品质因数基本保持不变,验证了该真空封装方案的可靠性.

  1. 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


    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 ...


    Institute of Scientific and Technical Information of China (English)

    林三宝; 宋建岭; 杨春利; 马广超


    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

  3. Phased array ultrasonic testing of dissimilar metal welds using geometric based referencing delay law technique (United States)

    Han, Taeyoung; Schubert, Frank; Hillmann, Susanne; Meyendorf, Norbert


    Phased array ultrasonic testing (PAUT) techniques are widely used for the non-destructive testing (NDT) of austenitic welds to find defects like cracks. However, the propagation of ultrasound waves through the austenitic material is intricate due to its inhomogeneous and anisotropic nature. Such a characteristic leads beam path distorted which causes the signal to be misinterpreted. By employing a reference block which is cutout from the mockup of which the structure is a dissimilar metal weld (DMW), a new method of PAUT named as Referencing Delay Law Technique (RDLT) is introduced. With the RDLT, full matrix capture (FMC) was used for data acquisition. To reconstruct the images, total focusing method (TFM) was used. After the focal laws were calculated, PAUT was then performed. As a result, the flaws are more precisely positioned with significantly increased signal-to-noise ratio (SNR).

  4. Induction brazing of complex joints

    DEFF Research Database (Denmark)

    Henningsen, Poul; Zhang, Wenqi; Bay, Niels


    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......, or if the hottest area is located outside the joint interface, a number of defects may appear: the braze metal may flow away from the joint, the flux may burn off, poor binding of the braze metal may appear or the braze metal may be overheated. Joint geometry as well as electro-magnetic properties of the work piece...

  5. Ultrasonic Time of Flight Diffraction Technique for Weld Defects: A Review

    Directory of Open Access Journals (Sweden)

    K. Manjula


    Full Text Available To achieve the quality and safety in industrial applications, the damaged products must be detected. To do that NDT is used. In NDT, Ultrasonic Time-of-Flight Diffraction is a well-known technique for detecting the size and location of the defects. Nowadays the Time of Flight Diffraction (ToFD is used for inspecting the materials during production than that of radiography and other ultrasonic NDT procedures. ToFD technique can be used into many different ways. This study gives a review of various ultrasonic ToFD techniques for welding defects and aims at the usage of it.

  6. 小口径水平固定管组合焊技术探索%Study on Composite Welding Technique for Small-caliber Horizontal Fixed Tubes

    Institute of Scientific and Technical Information of China (English)

    孙炎; 黄凤虎


    This article studies composite welding technique for small-caliber horizontal fixed tubes from such angles as its cleaning before welding, welding fabrication, welding techniques (SMAW and TIG welding), processing parameter, welding operation, welding inspection so as to improve the welding quality.%文章针对小口径水平固定管组合焊,研究了其焊前清理、焊接装配、焊接方法(焊条电弧焊和TIG焊)、工艺参数、操作方法、焊接检验等方面技术,对提高焊接质量具有一定的应用价值。

  7. Corrosion Behavior of Brazed Zinc-Coated Structured Sheet Metal


    Nikitin, A.; L. Schleuss; R. Ossenbrink; V. Michailov


    Arc brazing has, in comparison to arc welding, the advantage of less heat input while joining galvanized sheet metals. The evaporation of zinc is reduced in the areas adjacent to the joint and improved corrosion protection is achieved. In the automotive industry, lightweight design is a key technology against the background of the weight and environment protection. Structured sheet metals have higher stiffness compared to typical automobile sheet metals and therefore they can play an importan...

  8. Brazing Refractory Metals Used In High-Temperature Nuclear Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    A. J. Palmer; C. J. Woolstenhulme


    As part of the U. S. Department of Energy (DOE) sponsored Next Generation Nuclear Project (NGNP) currently ongoing at Idaho National Laboratory (INL), the irradiation performance of candidate high-temperature gas reactor fuels and materials is being evaluated at INL’s Advanced Test Reactor (ATR). The design of the first Advanced Gas Reactor (AGR 1) experiment, currently being irradiated in the ATR, required development of special techniques for brazing niobium and molybdenum. Brazing is one technique used to join refractory metals to each other and to stainless steel alloys. Although brazing processes are well established, it is difficult to braze niobium, molybdenum, and most other refractory metals because they quickly develop adherent oxides when exposed to room-temperature air. Specialized techniques and methods were developed by INL to overcome these obstacles. This paper describes the techniques developed for removing these oxides, as well as the ASME Section IX-qualified braze procedures that were developed as part of the AGR-1 project. All brazes were made using an induction coil with an inert or reducing atmosphere at low pressure. Other parameters, such as filler metals, fluxes used, and general setup procedures, are also discussed.

  9. On qualification of TOFD technique for austenitic stainless steel welds inspection

    Energy Technology Data Exchange (ETDEWEB)

    Martinez-Ona, R. [Tecnatom, San Sebastian de los Reyes (Spain); Viggianiello, S.; Bleuze, A. [Metalscan, Saint-Remy (France)


    Time of Flight Diffraction (TOFD) technique is gaining ground as a solid method for detection and sizing of defects. It has been reported that TOFD technique provides good results on the inspection of fine grain steels. However, there are few results regarding the application and performance of this technique on austenitic stainless steels. A big challenge of these inspections is the coarse grain structure that produces low signal to noise ratio and may mask the diffraction signals. Appropriate transducer design, selection of technique parameters and analysis tools could overcome the actual difficulties. In this paper, the main design aspects and parameters of the TOFD technique for austenitic steels are presented. It follows the description of qualification tests carried out to validate the technique for inspecting stainless steels welds. To conclude, discussion of results from actual inspections is shown. (orig.)

  10. Welding and Joining of Titanium Aluminides

    Directory of Open Access Journals (Sweden)

    Jian Cao


    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.

  11. Welding processes handbook

    CERN Document Server

    Weman, Klas


    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...

  12. Multiple exposure to metals in eight types of welding. (United States)

    Apostoli, P; Porru, S; Brunelli, E; Alessio, L


    This article evaluates multiple exposures to metals in different types of metal welding such as manual metal arc for mild and stainless steel, continuous wire, submerged arc, laser and brazing. Environmental monitoring was carried out in eight different occupational situations and the inductively coupled plasma mass spectrometry technique was adopted in order to characterize exposure to several elements simultaneously and with high accuracy. The results showed that up to 23 elements could be measured. The highest concentrations were found for Al, Mn, Fr, Ni, Cr, Cu and Zn. For some elements such as In, Nd, I, Rb the concentrations were very low. A qualitative and quantitative variation in fume composition was observed at a certain distance from the welding point, which should be to taken into account when evaluating indirect exposures. It would also be possible, with this technique, to identify specific elements in the mixture which could also be measured in biological fluids.

  13. Failure Assessment of Stainless Steel and Titanium Brazed Joints (United States)

    Flom, Yury A.


    Following successful application of Coulomb-Mohr and interaction equations for evaluation of safety margins in Albemet 162 brazed joints, two additional base metal/filler metal systems were investigated. Specimens consisting of stainless steel brazed with silver-base filler metal and titanium brazed with 1100 Al alloy were tested to failure under combined action of tensile, shear, bending and torsion loads. Finite Element Analysis (FEA), hand calculations and digital image comparison (DIC) techniques were used to estimate failure stresses and construct Failure Assessment Diagrams (FAD). This study confirms that interaction equation R(sub sigma) + R(sub tau) = 1, where R(sub sigma) and R(sub t u) are normal and shear stress ratios, can be used as conservative lower bound estimate of the failure criterion in stainless steel and titanium brazed joints.

  14. 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


    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.

  15. XRD and TEM analysis of the microstructure in the brazing joint of 3003 cladding aluminum alloy

    Institute of Scientific and Technical Information of China (English)

    Tao Feng; Songnian Lou; Luhai Wu; Yajiang Li


    The material used in this experiment was 3003 cladding aluminum alloy, the cladding metal was 4004 aluminum alloy.The aluminum plate was brazed by means of vacuum brazing. The microstructure in the brazing joint was studied by means of X-ray diffractometry (XRD) and transmission electron microscopy (TEM). The test result indicates that the suitable brazing technique parameters are brazing temperature, 628℃; keeping time, 10 min; vacuum degree, 6.5×10-4 Pa. XRD test indicates that there are new intermetallic compounds different from the base metal. TEM analysis indicates that Cu2Mg and Cu3Mn2Mg are formed in the brazing joint. The shape of Cu2Mg is irregular and the shape of Cu3Mn2Mg is circle, and there are tiny particles in it.

  16. 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


    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.

  17. 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;


    and use the manifold mapping technique to solve the optimization problems using a fast analytical coarse and an expensive accurate fine model. The statistics of the response are calculated using Taylor expansions and are compared to Monte Carlo simulations. The results show that the use of manifold......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...

  18. Brazing zone structure at active brazing of alumina ceramics

    Institute of Scientific and Technical Information of China (English)


    @@ 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.

  19. Brazing zone structure at active brazing of alumina ceramics

    Institute of Scientific and Technical Information of China (English)

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


    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.……

  20. Advanced Welding Applications (United States)

    Ding, Robert J.


    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.

  1. Cathodic ARC surface cleaning prior to brazing

    Energy Technology Data Exchange (ETDEWEB)

    Dave, V. R. (Vivek R.); Hollis, K. J. (Kendall J.); Castro, R. G. (Richard G.); Smith, F. M. (Frank M.); Javernick, D. A. (Daniel A.)


    Surface cleanliness is one the critical process variables in vacuum furnace brazing operations. For a large number of metallic components, cleaning is usually accomplished either by water-based alkali cleaning, but may also involve acid etching or solvent cleaning / rinsing. Nickel plating may also be necessary to ensure proper wetting. All of these cleaning or plating technologies have associated waste disposal issues, and this article explores an alternative cleaning process that generates minimal waste. Cathodic arc, or reserve polarity, is well known for welding of materials with tenacious oxide layers such as aluminum alloys. In this work the reverse polarity effect is used to clean austenitic stainless steel substrates prior to brazing with Ag-28%Cu. This cleaning process is compared to acid pickling and is shown to produce similar wetting behavior as measured by dynamic contact angle experiments. Additionally, dynamic contact angle measurements with water drops are conducted to show that cathodic arc cleaning can remove organic contaminants as well. The process does have its limitations however, and alloys with high titanium and aluminum content such as nickel-based superalloys may still require plating to ensure adequate wetting.

  2. Structural Performance of Inconel 625 Superalloy Brazed Joints (United States)

    Chen, Jianqiang; Demers, Vincent; Cadotte, Eve-Line; Turner, Daniel; Bocher, Philippe


    The purpose of this work was to investigate tensile and fatigue behaviors of Inconel 625 superalloy brazed joints after transient liquid-phase bonding process. Brazing was performed in a vacuum furnace using a nickel-based filler metal in a form of paste to join wrought Inconel 625 plates. Mechanical tests were carried out on single-lap joints under various lap distance-to-thickness ratios. The fatigue crack initiation and crack growth modes were examined via metallographic analysis, and the effect of local stress on fatigue life was assessed by finite element simulations. The fatigue results show that fatigue strength and endurance limit increase with overlap distance, leading to a relatively large scatter of results. Fatigue cracks nucleated in the high-stressed region of the weld fillets from brittle eutectic phases or from internal brazing cavities. The present work proposes to rationalize the results by using the local stress at the brazing fillet. When using this local stress, all fatigue-obtained results find themselves on a single S-N curve, providing a design curve for any joint configuration in fatigue solicitation.

  3. Applying a nonlinear, pitch-catch, ultrasonic technique for the detection of kissing bonds in friction stir welds. (United States)

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


    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.

  4. The story of laser brazing technology (United States)

    Hoffmann, Peter; Dierken, Roland


    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.

  5. 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


    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.

  6. 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


    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).

  7. 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: [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)


    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.

  8. Online monitoring of the laser brazing of titanium overlap joints (United States)

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


    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.


    Institute of Scientific and Technical Information of China (English)

    Lu Xueqin; Yang Shanglei; Wu Yixiong


    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.

  10. GEH-4-63, 64: Proposal for irradiation of production brazed Zircaloy-2 clad fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Tverberg, J.C.


    A brazed end closure is currently being used on prototypical NPR fuel elements. The production closure will use a braze alloy composed of 5% Be + 95% Zry-2 to braze the Zircaloy-2 cap to the jacket and to the metallic uranium core. A similar MTR test, a GEH-4-57, 58, used a braze alloy of the composition 4% Be + 12% Fe + 84% Zry-2 which melts at a lower temperature. In this previous test, element GEH-4-57 failed through a cladding defect located at the base of the braze heat affected zone. Because of this failure it would be desirable to subject a fuel element, which had been subjected to more severe brazing conditions, to the same conditions as GEH-4-57, 58. For this reason the thermal conditions of this test essentially match those of GEH-4-57, 58. This irradiation test consists of two identical fuel elements. The fuel material is normal metallic uranium, Zircaloy-2 clad of the tubular geometry, NPR inner size. The fuel was coextruded at Hanford by General Electric`s Fuels Preparation Department. Each element is 10.8 inches in length with flat Zircaloy-2 end caps brazed to the jacket and uranium core with the 5 Be + 95 Zry-2 brazing alloy, then TIG welded to further insure closure integrity. The elements ar 1.254 inches OD and 0.439 inches ID. For hydraulic purposes a 0.343 inch diamater flow restrictor has been fitted into the central flow channel of both elements.

  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)


    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. 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:; 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)


    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.

  13. Corrosion Mechanisms in Brazed Al-Base Alloy Sandwich Structures as a Function of Braze Alloy and Process Variables (United States)


    produce results on precipitation hardened Al alloys which provide a good indicator of long term field exposure performance in natural environments [15...I \\ I I i i I i i i I 750 ZOO AI-0.15Cu-0.9Mg-0.6Si (wt%) J50 m 100 10000 1000 10000 100000 1000000 i 10o Time, min Time...for good corrosion resistance and simultaneous weld penetration to achieve bonding vi. Designed New Braze alloy based on combined metallurgical

  14. Evaluation of laser welding techniques for hydrogen transmission. Final report, September 1977-November 1979

    Energy Technology Data Exchange (ETDEWEB)

    Mucci, J


    This program was established to determine the feasibility of laser beam welding as a fabrication method for hydrogen transmission and is a precursor in the effort to systematically provide the technological base necessary for large-scale, economic pipeline transmission of fuel for a hydrogen energy system. The study contributes to the technology base by establishing the effect of conventional weld processes and laser beam welding on the mechanical properties of two classes of steels in an air and high pressure gaseous hydrogen environment. Screening evaluation of the tensile, low-cycle fatigue and fracture toughness properties and metallurgical analyses provide the basis for concluding that laser beam welding of AISI 304L stainless steel and ASTM A106B carbon steel can produce weldments of comparable quality to those produced by gas-tungsten arc and electron beam welding and is at least equally compatible with 13.8 MPa (2000 psig) gaseous hydrogen environment.

  15. Laser beam active brazing of metal ceramic joints (United States)

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


    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.

  16. Mechanistic understanding of aerosol emissions from a brazing operation. (United States)

    Zimmer, A T; Biswas, P


    Welding operations produce gaseous and aerosol by-products that can have adverse health effects. A laboratory furnace study was conducted to aid understanding of the chemical and aerosol behavior of a widely used, self-fluxing brazing alloy (89% Cu, 6% Ag, 5% P) that is also used with a supplemental fluxing compound to prevent oxidation at the molten metal surface. The results indicate that the aerosols generated by the alloy are transient (produced over a short duration of time) and are associated with mass transfer of phosphorus species from the molten metal surface to the surrounding gas. In contrast, when the alloy was used in conjunction with the supplemental fluxing compound, a relatively nontransient, submicron-size aerosol was generated that was several orders of magnitude higher in concentration. Thermodynamic equilibrium analysis suggests that fluoride (a major constituent in the fluxing compound) played a significant role in reacting with the brazing alloy metals to form gas phase metal fluoride compounds that had high vapor pressures when compared with their elemental or oxide forms. As these metal-fluoride vapors cooled, submicron-size particles were formed mainly through nucleation and condensation growth processes. In addition, the equilibrium results revealed the potential formation of severe pulmonary irritants (HF and BF3) from heating the supplemental fluxing compound. These results demonstrated the importance of fluxing compounds in the formation of brazing fumes, and suggest that fluxing compounds could be selected that serve their metallurgical intention and suppress the formation of aerosols.

  17. Interfacial microstructure and mechanical properties of brazed aluminum / stainless steel - joints (United States)

    Fedorov, V.; Elßner, M.; Uhlig, T.; Wagner, G.


    Due to the demand of mass and cost reduction, joints based on dissimilar metals become more and more interesting. Especially there is a high interest for joints between stainless steel and aluminum, often necessary for example for automotive heat exchangers. Brazing offers the possibilities to manufacture several joints in one step at, in comparison to fusion welding, lower temperatures. In the recent work, aluminum / stainless steel - joints are produced by induction brazing using an AlSi10 filler and a non-corrosive flux. The mechanical properties are determined by tensile shear tests as well as fatigue tests at ambient and elevated temperatures. The microstructure of the brazed joints and the fracture surfaces of the tested samples are investigated by SEM.

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

    Directory of Open Access Journals (Sweden)

    S.C. Nwigbo


    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 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.

  19. Qualification of final closure for disposal container II - applicability of TOFD and phased array technique for overpack welding

    Energy Technology Data Exchange (ETDEWEB)

    Asano, H.; Kawahara, K. [Radioactive Waste Management Funding and Research Center (RWMC) (Japan); Arakawa, T. [Ishikawajima-Harima Heavy Industries Co. Ltd. (Japan); Kurokawa, M. [Mitsubishi Heavy Industries Ltd. (Japan)


    With a focus on carbon steel, which is one of the candidate materials for the disposal container used in the geological disposal of high-level radioactive waste in Japan, the defect detection capabilities were examined regarding engineering defects of the TOFD technique, an ultrasonic testing method, and the phased array TOFD technique as non-destructive test techniques for the inspection of the weld of a carbon steel overpack. Regarding the TOFD technique, a measurement was conducted concerning the influence of the crossing angle of the ultrasonic beams on the capability of detect flaws, for examining the detection characteristics of the technique in relation to the lid structure of an overpack, and it was pointed out that it is appropriate to consider the lower tip of slit as the reference flaw. Based on the measurements and calculations regarding sound pressure distribution, projections about the scope covered by one test session were made and the optimum testing conditions were examined. Regarding the phased array TOFP technique, the detectability and quantification characteristics were investigated, and comparisons with those of the TOFD technique and the phased array UT technique were made. From the viewpoint of securing long-term corrosion resistance for an overpack, the ways of thinking for ensuring the quality and long-term integrity of the final sealing area of a disposal container were examined. This study stresses that identifying and defining the defects that are harmful to corrosion allowance is important as well as achieving improvements in the welding and testing techniques, and that the question to solve in particular from now on is how to establish effective means to detect defects on the weld surface and the near surface and how to approach the level of tolerance concerning the defects on and near the surface. (orig.)

  20. Weldability and Welding Technique of 2101 Duplex Stainless Steel%2101双相不锈钢的焊接性能和焊接技术

    Institute of Scientific and Technical Information of China (English)

    刘长文; 邓钢; 曾广庭


    对2101双相不锈钢的焊接性能进行了分析,并提出了几个关键的焊接技术,最后以12.7mm厚2101双相不锈钢板为例,进行了该材料的焊接工艺评定。结果表明:在合理的焊接方法和焊接参数下,2101双相不锈钢具有良好的焊接性能。%Weldability of 2101 duplex stainless steel was analyzed, several key welding techniques were put forward, and finally welding procedure qualification was done taken 12. 7 mm 2101 duplex stainless steel plate as an example. The results show that 2101 duplex stainless steel has good welding performance under the condition of reasonable welding method and welding parameters.

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

    Institute of Scientific and Technical Information of China (English)



    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.

  2. Welding Course Curriculum. (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…

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

    Directory of Open Access Journals (Sweden)

    Nabeel K. Abid AL-Sahib


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

  4. Improved diffusion welding and roll welding of titanium alloys (United States)

    Holko, K. H.


    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.

  5. 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.


    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)

  6. 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)


    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.

  7. 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


    @@ 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.

  8. Simulation based analysis of laser beam brazing (United States)

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


    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. Fracture strength of different soldered and welded orthodontic joining configurations with and without filling material. (United States)

    Bock, Jens Johannes; Bailly, Jacqueline; Gernhardt, Christian Ralf; Fuhrmann, Robert Andreas Werner


    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 (pfracture 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 (pfracture 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.

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

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Coniglio, Nicolas


    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

  12. Development of the manufacture and process for DUPIC fuel elements; development of the quality evaluation techniques for end cap welds of DUPIC fuel elements

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Tae; Choi, Myong Seon; Yang, Hyun Tae; Kim, Dong Gyun; Park, Jin Seok; Kim, Jin Ho [Yeungnam University, Kyongsan (Korea)


    The objective of this research is to set up the quality evaluation techniques for end cap welds of DUPIC fuel element. High temperature corrosion test and the SCC test for Zircaloy-4 were performed, and also the possibility of the ultrasonic test technique was verified for the quality evaluation and control of the laser welds in the DUPIC fuel rod end cap. From the evaluation of corrosion properties with measuring the weight gain and observing oxide film of the specimen that had been in the circumstance of steam(400 .deg. C, 1,500 psi) by max. 70 days later, the weight gain of the welded specimens was larger than original tube and the weight increasing rate increased with the exposed days. For the Development of techniques for ultrasonic test, semi-auto ultrasonic test system has been made based on immersion pulse-echo technique using spherically concentrated ultrasonic beam. Subsequently, developed ultrasonic test technique is quite sensible to shape of welds in the inside and outside of tube as well as crack, undercut and expulsion, and also this ultrasonic test, together with metallurgical fracture test, has good reliance as enough to be used for control method of welding process. 43 refs., 47 figs., 8 tabs. (Author)

  13. 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


    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)

  14. 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)


    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

  15. 铜触头的高频钎焊%High-frequency brazing a copper contact

    Institute of Scientific and Technical Information of China (English)

    刘轶强; 张狄林


    叙述了焊接一种大面积铜触头由气体火焰钎焊改为高频钎焊的研究过程.通过更换钎料,设计合适的感应线圈,选用合适的焊接工艺参数,焊接出合格的产品.经肉眼观察、滚压实验、金相分析和扫描电镜的全面检测,触头的高频钎焊质量优良,符合设计要求.该研究对提高铜触头的焊接合格率,降低生产成本,节省焊接时间并大幅提高生产率,减轻劳动强度和改善劳动环境都有极大的价值.%This paper describes a large area of copper contact welding by the gas flame brazing replaced by high-frequency brazing process.By replacing the induction coil of solder,design appropriate, the appropriate choice of welding parameters, welding of qualified products. By the virual inspection ,rolling experiments, metallographic analysis and scanning electron microscope,a comprehensive inspection,the contact by high-frequency brazing has good quality and meets the design requirements. This study has great value for the company to improve the pass rate of welding of copper contacts,reduces production costs,saves the welding lime and dramatically increases productivity, reduces labor intensity and improves the working environment.

  16. Brazing Inconel 625 Using the Copper Foil (United States)

    Chen, Wen-Shiang; Wang, Cheng-Yen; Shiue, Ren-Kae


    Brazing Inconel 625 (IN-625) using the copper foil has been investigated in this research. The brazed joint is composed of nanosized CrNi3 precipitates and Cr/Mo/Nb/Ni quaternary compound in the Cu/Ni-rich matrix. The copper filler 50 μm in thickness is enough for the joint filling. However, the application of Cu foil 100 μm in thickness has little effect on the shear strength of the brazed joint. The specimen brazed at 1433 K (1160 °C) for 1800 seconds demonstrates the best shear strength of 470 MPa, and its fractograph is dominated by ductile dimple fracture with sliding marks. Decreasing the brazing temperature slightly decreases the shear strength of the brazed joint due to the presence of a few isolated solidification shrinkage voids smaller than 15 μm. Increasing the brazing temperature, especially for the specimen brazed at 1473 K (1200 °C), significantly deteriorates the shear strength of the joint below 260 MPa because of coalescence of isothermal solidification shrinkage voids in the joint. The Cu foil demonstrates potential in brazing IN-625 for industrial application.

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

    Energy Technology Data Exchange (ETDEWEB)

    Coniglio, Nicolas


    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

  18. Brazed Joints Design and Allowables: Discuss Margins of Safety in Critical Brazed Structures (United States)

    FLom, Yury


    This slide presentation tutorial discusses margins of safety in critical brazed structures. It reviews: (1) the present situation (2) definition of strength (3) margins of safety (4) design allowables (5) mechanical testing (6) failure criteria (7) design flowchart (8) braze gap (9) residual stresses and (10) delayed failures. This presentation addresses the strength of the brazed joints, the methods of mechanical testing, and our ability to evaluate the margins of safety of the brazed joints as it applies to the design of critical and expensive brazed assemblies.

  19. Technique for the residual life assessment of high temperature components based on creep-rupture testing on welded miniature specimens

    Energy Technology Data Exchange (ETDEWEB)

    Garzillo, A.; Guardamagna, C.; Moscotti, L.; Ranzani, L. [Ente Nazionale per l`Energia Elettrica, Milan (Italy)


    Following the present trend in the development of advanced methodologies for residual life assessment of high temperature components operating in power plants, particularly in non destructive methods, a testing technique has been set up at ENEL-CRAM based on creep-rupture testa in an argon on welded miniature specimens. Five experimental systems for creep-rupture tests in an argon atmosphere have been set up which include high accuracy systems, vacuum chambers and exrwnsometer devices. With the aim of establishing and validating the suitability of the experimental methodology, creep-rupture and interrupted creep testing programmes have been performed on miniature specimens (2 mm diameter and 10 mm gauge lenght). On the basis of experience gathered by various European research laboratories, a miniature specimen construction procedure has been developed using a laser welding technique for joining threaded heads to sample material. Low alloy ferritic steels, such as virgin 2.25CrlMo, 0.5Cr 0.5Mo 0.25V, and IN 738 superalloy miniature specimens have been investigated and the results, compared with those from standard specimens, show a regular trend in deformation vs time. Additional efforts to provide guidelines for material sampling from each plant component will be required in order to reduce uncertainties in residual life prediction.

  20. 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: [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil)


    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)

  1. Combined scale effects for effective brazing at low temperatures

    Directory of Open Access Journals (Sweden)

    Bartout D.


    Full Text Available In modern joining technology, the focus is on effective brazing and soldering of temperature sensitive materials. Here, as well as in diffusion welding processes the needed thermal energy is externally realized in the joint zone. This produces a heating of the whole joining parts, since in laminar joining the thermal energy is transported in interior by thermal conduction. An excess of critical temperatures or tolerable impact periods in wide parts of materials and respectively components is often not avoidable. This leads to thermal damages. In this point of view nanotechnology shows promising possibilities as scale effects and their resulting thermophysical effects such as melting temperature reduction and high diffusion rates can be used for providing a self-propagating high-temperature synthesis at room temperature. After ignition by an external energy source a self-propagating exothermic reaction is started. By producing a multilayer system with alternately arranged nanoscaled layers of e.g. Al and Ni the resulting thin foil can be used as heat source for melting the braze or solder material within the joining zone without any external preheating. Due to the high process velocities up to 30 m/s and the local heat input significant thermal influences on the joined parts are not detectable.

  2. Braze/Rebraze process for CRES steel (United States)

    Silverman, C. E.


    Using induction brazing process with 8.5-Au/16.5-Cu/2.0-Ni braze alloy, joints in 21-6-9 CRES steel tubing can be reworked up to seven times, thus significantly reducing cost of fabrication, repair, and part replacement.

  3. Automatic-Control System for Safer Brazing (United States)

    Stein, J. A.; Vanasse, M. A.


    Automatic-control system for radio-frequency (RF) induction brazing of metal tubing reduces probability of operator errors, increases safety, and ensures high-quality brazed joints. Unit combines functions of gas control and electric-power control. Minimizes unnecessary flow of argon gas into work area and prevents electrical shocks from RF terminals. Controller will not allow power to flow from RF generator to brazing head unless work has been firmly attached to head and has actuated micro-switch. Potential shock hazard eliminated. Flow of argon for purging and cooling must be turned on and adjusted before brazing power applied. Provision ensures power not applied prematurely, causing damaged work or poor-quality joints. Controller automatically turns off argon flow at conclusion of brazing so potentially suffocating gas does not accumulate in confined areas.

  4. Novel approach of LY12 alloy brazing

    Institute of Scientific and Technical Information of China (English)

    薛松柏; 钱乙余; 董健; 吕晓春


    The LY12 Al alloy was brazed with the adoption of the improved KF-CsF-AlF3 flux matching Ag-Al-Cu-Zn filler metal. The shear strength of brazed joint could reach 80% of that of the substrate and the tensile strength of butt brazed joint will be 70% of that of the substrate. This was the great progress against the traditional claim that Al alloy reinforced by heat treatment could not be brazed. The experimental results and theoretical analysis had proved that it was the key issue to remove the MgO oxide film below 503℃. The addition of rare earth La was the effective way to obtain better mechanical properties of the filler metal as well as brazed joints.

  5. Effect of ultrasonic transmission rate on microstructure and properties of the ultrasonic-assisted brazing of Cu to alumina. (United States)

    Ji, Hongjun; Chen, Hao; Li, Mingyu


    Fluxless brazing of bare alumina with Cu was conducted with an ultrasonic-assisted brazing technique by a Zn-14wt.%Al filler. The shear strength of Cu/alumina joints (84MPa) exhibited 27% larger than the alumina/Cu joints (66MPa) due to different intermetallic phases and their morphologies formed in the seam under the same parameters, which are probably attributed to the transmission rate of ultrasonic energy varying with density of the ultrasonic horn-contacted materials. Overgrowth of stalactite-like CuZn5 contributes to better thermal dissipation of the ultrasonic-assisted brazed Cu/alumina joints.

  6. Detached Melt Nucleation during Diffusion Brazing of a Technical Ni-based Superalloy: A Phase-Field Study (United States)

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


    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.

  7. Welding arc plasma physics (United States)

    Cain, Bruce L.


    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.

  8. Theory and modeling of active brazing.

    Energy Technology Data Exchange (ETDEWEB)

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


    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.

  9. Challenges to Resistance Welding

    DEFF Research Database (Denmark)

    Song, Quanfeng

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

  10. 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:; 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)


    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

  11. Microstructure and characteristics of high dimension brazed joints of cermets and steel

    Directory of Open Access Journals (Sweden)

    J. Nowacki


    Full Text Available Purpose: In the article a state of the question concerning stresses in brazing joints of different physical and mechanical properties was appraised as well as possibility of their decrease due to use of different techniques from technological experiments to numerical methods. Evaluation of microstructure and mechanical properties of large dimensional vacuum brazed joints of WC – Co and Ferro Titanit Nicro 128 sinters and precipitation hardened stainless steel of 14 –5 PH (X5CrNiMoCuNb14-5 using copper and silver – copper as the brazing filler metal.Design/methodology/approach: Microscopic examinations with the use of scanning electron microscope (SEM were performed to establish microstructure and diffusion influences on creation of intermetallic phases in the joint. Shear strength Rt and tensile strength Rm of the joints have been defined. It 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 the cermets and brazing filler metal elements and creation of intermetallic in the joint. It can have an unfavourable influence on ductility and quality of the joint.Findings: Results of numerical calculations of two-dimensional models of brazed joints for different sizes of surfaces brazed at a constant width of solder gap are presented. Particular attention was paid to stresses occurring in joints of large brazing surfaces.Results of the investigate proved that joints microstructure and mechanical properties depend on filler and parent materials, diffusion process during brazing, leading to exchange of the cermets components and filler metal as well as joint geometry (mainly gap thickness.Practical implications: The results have been applied in surfaces are used in large dimension spinning nozzles of a die for polyethylene granulation, in that

  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


    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.



  14. Feasibility study of fluxless brazing cemented carbides to steel (United States)

    Tillmann, W.; Sievers, N.


    One of the most important brazing processes is the joints between cemented carbides and steel for the tool industry such as in rotary drill hammers or saw blades. Even though this technique has already been used for several decades, defects in the joint can still occur and lead to quality loss. Mostly, the joining process is facilitated by induction heating and the use of a flux to enhance the wetting of the filler alloy on the surface of the steel and cemented carbide in an ambient atmosphere. However, although the use of flux enables successful joining, it also generates voids within the joint, which reduces the strength of the connection while the chemicals within the flux are toxic and polluting. In this feasibility study, a fluxless brazing process is used to examine the joint between cemented carbides and steel for the first time. For this, ultrasound is applied during induction heating to enable the wetting between the liquid filler metal and the surfaces of the cemented carbide and steel. The ultrasound generates cavitations within the liquid filler metal, which remove the oxides from the surface. Several filler metals such as a silver based alloy Ag449, pure Zn, and an AlSi-alloy were used to reduce the brazing temperature and to lower the thermal residual stresses within the joint. As a result, every filler metal successfully wetted both materials and led to a dense connection. The ultrasound has to be applied carefully to prevent a damage of the cemented carbide. In this regard, it was observed that single grains of the cemented carbide broke out and remained in the joint. This positive result of brazing cemented carbides to steel without a flux but using ultrasound, allows future studies to focus on the shear strength of these joints as well as the behavior of the thermally induced residual stresses.

  15. Failure Assessment Diagram for Titanium Brazed Joints (United States)

    Flom, Yury; Jones, Justin S.; Powell, Mollie M.; Puckett, David F.


    The interaction equation was used to predict failure in Ti-4V-6Al joints brazed with Al 1100 filler metal. The joints used in this study were geometrically similar to the joints in the brazed beryllium metering structure considered for the ATLAS telescope. This study confirmed that the interaction equation R(sub sigma) + R(sub Tau) = 1, where R(sub sigma) and R(sub Tau)are normal and shear stress ratios, can be used as conservative lower bound estimate of the failure criterion in ATLAS brazed joints as well as for construction of the Failure Assessment Diagram (FAD).

  16. Studies of welded joints

    Directory of Open Access Journals (Sweden)

    J. M. Krupa


    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.

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

    Directory of Open Access Journals (Sweden)

    Kristína Demianová


    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.

  18. Microstructural Evolution of Infrared Brazed CP-Ti Using Ti-Cu-Ni Brazes

    Institute of Scientific and Technical Information of China (English)

    C.T.Chang; T.Y.Yeh; R.K.Shiue; C.S.Chang


    Microstructural evolution of infrared vacuum brazed CP-Ti using two Ti-based braze alloys, Ti-15Cu-15Ni and Ti-15Cu-25Ni, has been investigated. The infrared braze d joint consisted of eutectic Ti2Cu/Ti2Ni intermetallic compounds and Ti-rich matrix. The eutectic Ti2Cu/Ti2Ni intermetallic compounds disappeared from the joint after being annealed at 900℃ for 1 h. In contrast, the depletion rate of both Cu and Ni from the braze alloy into CP-Ti substrate at 750℃ annealing was greatly decreased as compared with that annealed at 900℃. Blocky Ti2Cu/Ti2Ni phases were observed even if the specimen was annealed at 750℃ for 15 h. Because the Ni content of the Ti-15Cu-25Ni braze alloy is much higher than that of the Ti-15Cu-15Ni alloy, the amount of eutectic Ti2Cu/Ti2Ni phases in Ti-15Cu-25Ni brazed joint is more than that in Ti-15Ci-15Ni brazed joint. However, similar microstructural evolution can be obtained from the infrared brazed joint annealed at various temperatures and/or time for both filler metals.

  19. Welding Curriculum. (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.…

  20. Development of brazing process for W-EUROFER joints using Cu-based fillers (United States)

    de Prado, J.; Sánchez, M.; Ureña, A.


    A successful joint between W and EUROFER using high temperature brazing technique has been achieved for structural application in future fusion power plants. Cu-based powder alloy mixed with a polymeric binder has been used as filler. Microstructural analysis of the joints revealed that the joint consisted mainly of primary phases and acicular structures in a Cu matrix. Interaction between EUROFER and filler took place at the interface giving rise to several Cu-Ti-Fe rich layers. A loss of hardness at the EUROFER substrate close to the joint due to a diffusion phenomenon during brazing cycle was measured; however, the joints had an adequate shear strength value.

  1. Inert Welding/Brazing Gas Filters and Dryers (United States)

    Goudy, Jerry


    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. 铝与钢、不锈钢、铜焊接,复合板制备及匙孔填充新技术——搅拌摩擦钎焊(FSB)的系列应用%New Techniques for Joining Aluminum/Steel, Aluminum/Stainless Steel and Aluminum/Copper, Fabricating Bimetallic Composite Plate and Filling Keyhole Based on Friction Stir Brazing (FSB)

    Institute of Scientific and Technical Information of China (English)

    张贵锋; 焦伟民; 张建勋; 王士元


    In order to overcome the wear of pin by the hard parent metal during friction stir welding (FSW), a novel process of friction stir brazing (FSB) was developed by Welding Research Institute, XPan Jiaotong University.Using the novel process,lap joints of Al/steel, Al/Cu , Al/stainless steel, and Al/steel, Al/stainless steel bimetallic composite plates were successfully prepared.Compared with furnace brazing, FSB has the following advantages: atmospheric environment, clean frictional heat source, the tool without pin and suitable filler metal beneficial to oxide film removal. While comparing with traditional FSW,the characteristics of FSB Can be summarized as follows;rapid dissolution of base metals, instead of the deformation of hard parent metal; multiple mechanisms of interfacial extruding and torsion action, undermining (with aid of filler metal) and extrusion of liquid phase to remove the oxide film; elimination wear of the pin by steel parent metal and no keyhole.%对传统搅拌摩擦焊因针的磨损而难以适应较硬金属材料的不足,西安交通大学开发了一种“搅拌摩擦钎焊(friction stir brazing:FSB)”专利技术,并利用该技术成功焊接了铝/钢、铝/铜和铝/不锈钢异种金属搭接接头,且成功焊接了铝/钢和铝/不锈钢双金属复合板.该技术以洁净高效的摩擦热为热源,采用无针柱状搅拌头,并预置合适钎料在大气环境下施焊.与传统炉中钎焊相比,因工具对界面的挤压与扭转作用,具有明显的去膜优势;与传统搅拌摩擦焊相比,该技术用母材的快速溶解代替较硬材料的塑性变形,通过“界面扭转、挤压+膜下潜流(钎料的加入)+加压挤出”多种机制有效去除母材表面的氧化膜,且可以避免较硬材料对搅拌头针端的磨损,不产生匙孔.

  3. High-strength braze joints between copper and steel (United States)

    Kuhn, R. F.


    High-strength braze joints between copper and steel are produced by plating the faying surface of the copper with a layer of gold. This reduces porosity in the braze area and strengthens the resultant joint.

  4. Corrosion studies using potentiodynamic and EIS electrochemical techniques of welded lean duplex stainless steel UNS S82441 (United States)

    Brytan, Z.; Niagaj, J.; Reiman, Ł.


    The corrosion characterisation of lean duplex stainless steel (1.4662) UNS S82441 welded joints using the potentiodynamic test and electrochemical impedance spectroscopy in 1 M NaCl solution are discussed. The influence of autogenous TIG welding parameters (amount of heat input and composition of shielding gases like Ar and Ar-N2 and an Ar-He mixture), as well as A-TIG welding was studied. The influence of welding parameters on phase balance, microstructural changes and the protective properties of passive oxide films formed at the open circuit potential or during the anodic polarisation were studied. From the results of the potentiodynamic test and electrochemical impedance spectroscopy of TIG and A-TiG, welded joints show a lower corrosion resistance compared to non-welded parent metal, but introducing heat input properly during welding and applying shielding gases rich in nitrogen or helium can increase austenitic phase content, which is beneficial for corrosion resistance, and improves surface oxide layer resistance in 1 M NaCl solution.

  5. A study of weld quality in ultrasonic spot welding of similar and dissimilar metals (United States)

    Al-Sarraf, Z.; Lucas, M.


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

  6. 铸铁焊补特殊工艺研究与应用实践%Study and application on special repair welding technique of iron-castings

    Institute of Scientific and Technical Information of China (English)



    在生产实际中常常会遇到铸铁件的焊接修复.冷焊工艺由于焊前不预热、劳动条件好、成本低、周期短等优点,已成为铸件焊补的首选工艺.在实践中发现,仅采用普通的冷焊工艺,其产生白口、淬硬组织和应力的倾向比热焊大,很难获得满意的焊补质量,若在焊补中采取一些特殊的工艺措施,能收到较好的效果.详细分析了自制铜钢焊条焊补法、水浸焊补法、栽丝焊补法、镶块焊补法以及镶边铺底过渡焊补法等特殊焊补工艺的原理、特点和适用范围,并列举了典型应用实例,对铸铁件的焊补修复具有参考价值.%In actual production,the cast-iron stocks often are repaired.Cold welding technology has become the preferred process for use in repair welding of iron-castings, due to non-preheat, low cost.short cycle and good labor is founded that it is diffcult for repair welding of iron-castings to obtain satisfied weld quality,only to use ordinary cold welding technology which is more sensitive to quench tissue,crack and welding stress than hot welding.If some special repair welding technique be used,high quality weld can be obtained.Based on many years of research and application experience,The paper analyses in detail the principle,process features and applicable scope of special repair welding techniques,such as the self-made iron-castings electrode by ordinary carbon steel electrode,water-cooling welding,planting bolt welding,filling groove with steel plate and surfacing groove face etc,some typical application examples are given.These special repair welding techniques have guiding funtion on repair welding of cast-iron stocks.

  7. 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)


    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.)

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

    Directory of Open Access Journals (Sweden)

    Jens Johannes Bock


    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.

  9. 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: [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)


    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.


    Directory of Open Access Journals (Sweden)

    BURCA Mircea


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

  11. 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


    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.


    Gilliland, R.G.; Patriarca, P.; Slaughter, G.M.; Williams, L.C.


    A new and improved ternary alloy is described which is of particular utility in braze-bonding parts made of a refractory metal selected from Group IV, V, and VI of the periodic table and alloys containing said metal as a predominating alloying ingredient. The brazing alloy contains, by weight, 40 to 50 per cent zirconium, 40 to 50 per cent titanium, and the balance beryllium in amounts ranging from 1 to 20 per cent, said alloy having a melting point in the range 950 to 1400 deg C. (AEC)

  13. Braze Development of Graphite Fiber for Use in Phase Change Material Heat Sinks (United States)

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


    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.

  14. Methods to Predict Stresses in Cutting Inserts Brazed Using Iron-Carbon Brazing Alloy (United States)

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


    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.

  15. Welding Technician (United States)

    Smith, Ken


    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…

  16. 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


    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.

  17. Investigation of the effect of rapidly solidified braze ribbons on the microstructure of brazed joints (United States)

    Bobzin, K.; Öte, M.; Wiesner, S.; Rochala, P.; Mayer, J.; Aretz, A.; Iskandar, R.; Schwedt, A.


    Shrinkage and warpage due to melting and solidification are crucial for the geometric precision of related components. In order to assure a high geometric precision, the formation of the microstructure in the joint during brazing must be taken into consideration. An extensive interaction can occur between liquid melt and base material, resulting in the formation of distinctive phases. This interaction depends on the parameters of the brazing process. However, the consequences of the interaction between phase formation and process parameters in terms of geometric precision cannot be estimated yet. Insufficient quality of the joint can be a result. In this study, investigations focus on the process of solidification in terms of time dependent diffusion behavior of elements. Therefore, microcrystalline and amorphous braze ribbons based on Ti are produced by rapid solidification and are used for joining. The microstructure of the braze ribbons as well as the melting behavior and phase formation during brazing are considered to be of particular importance for the mechanical properties of the brazed components.

  18. Active Metal Brazing and Characterization of Brazed Joints in Titanium to Carbon-Carbon Composites (United States)

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


    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.

  19. EMAT weld inspection and weld machine diagnostic system for continuous coil processing lines (United States)

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


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  1. Magnetic Pulse Welding Technology

    Directory of Open Access Journals (Sweden)

    Ahmad K. Jassim


    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.

  2. Resistance welding

    DEFF Research Database (Denmark)

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


    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...

  3. Laser Brazing of Aluminum with a New Filler Wire AlZn13Si10Cu4 (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.

  4. ARC welding method for bonding steel with aluminum

    Institute of Scientific and Technical Information of China (English)

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


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


    Institute of Scientific and Technical Information of China (English)



    介绍了火箭发动机喷管真空加压钎焊技术工艺原理及特点,真空加压钎焊设备的结构和工艺过程.该技术工艺是对火箭发动机喷管夹层抽空,在达到钎焊温度时.炉膛内充人保护性气体.满足工艺所需0.8 MPa的外压力条件,对火箭发动机喷管形成真空钎焊与真空扩散焊两种焊接方式相结合的综合性工艺方法.%This paper introduces a rocket engine spout vacuum and pressure brazing technology principle and characteristic of vacuum braze welding, introduces the structure and process equipment. The technology is on the rocket engine spout dissection in time, to the temperature within the furnace brazing, filled with protective gas, process to meet the required 0.8Mpa outer pressure condition, the rocket engine spout to form a vacuum brazing and vacuum diffusion welding two welding methods of combining a comprehensive process.

  6. A study of processes for welding pipelines

    Energy Technology Data Exchange (ETDEWEB)

    Weston, J. (ed.)


    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.

  7. 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


    @@ 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.

  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


    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. Several braze filler metals for joining an oxide-dispersion-strengthened nickel-chromium-aluminum alloy (United States)

    Gyorgak, C. A.


    An evaluation was made of five braze filler metals for joining an aluminum-containing oxide dispersion-strengthened (ODS) alloy, TD-NiCrAl. All five braze filler metals evaluated are considered suitable for joining TD-NiCrAl in terms of wettability and flow. Also, the braze alloys appear to be tolerant of slight variations in brazing procedures since joints prepared by three sources using three of the braze filler metals exhibited similar brazing characteristics and essentially equivalent 1100 C stress-rupture properties in a brazed butt-joint configuration. Recommendations are provided for brazing the aluminum-containing ODS alloys.

  10. 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


    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)

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

  12. TIG-dressing of High Strength Steel Butt Welded Connections. Part 1: Weld Toe Geometry and Local Hardness

    NARCIS (Netherlands)

    Van Es, S.H.J.; Kolstein, M.H.; Pijpers, R.J.M.; Bijlaard, F.S.K.


    This paper presents the results of extensive measurements on weld toe geometry of as-welded and TIG-dressed butt welded connections in high strength steels S460, S690 and very high strength steels S890 and S1100. Descriptions of the measurement techniques and data analysis are presented. Four weld t

  13. TIG-dressing of high strength steel butt welded connections - Part 1: weld toe geometry and local hardness

    NARCIS (Netherlands)

    Es, S.H.J. van; Kolstein, M.H.; Pijpers, R.J.M.; Bijlaard, F.S.K.


    This paper presents the results of extensive measurements on weld toe geometry of as-welded and TIG-dressed butt welded connections in high strength steels S460, S690 and very high strength steels S890 and S1100. Descriptions of the measurement techniques and data analysis are presented. Four weld t

  14. The Effect of Tool Position for Aluminum and Copper at High Rotational Friction Stir Welding


    Recep Çakır; Sare Çelik


    Friction Stir Welding (FSW) is a solid state welding process used for welding similar and dissimilar materials. This welding technique allows welding of Aluminum alloys which present difficulties in fusion joining and allows different material couples to be welded continuously. In this study, 1050 aluminum alloy and commercially pure copper to increase heat input were produced at high rotation rate (2440 rev/min) with four different pin position (0-1-1.5-2 mm) and three different weld speeds ...

  15. [New welding processes and health effects of welding]. (United States)

    La Vecchia, G Marina; Maestrelli, Piero


    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.

  16. Spot brazing of aluminum to copper with a cover plate (United States)

    Hayashi, Junya; Miyazawa, Yasuyuki


    It is difficult to join dissimilar metals when an intermetallic compound is formed at the joining interface. Spot brazing can be accomplished in a short time by resistance heating. Therefore, it is said that the formation of a intermetallic compound can be prevented. In this study, aluminum and copper were joined by spot brazing with a cover plate. The cover plate was used to supply heat to base metals and prevent heat dissipation from the base metals. The ability to braze Al and Cu was investigated by observation and analysis. Pure aluminum (A1050) plate and oxygen-free copper (C1020) plate were used as base metals. Cu-Ni-Sn-P brazing filler was used as the brazing filler metal. SPCC was employed as cover plate. Brazing was done with a micro spot welder under an argon gas atmosphere. Brazing ability was estimated by tensile shear strength and cross sectional microstructure observation. Al and Cu can be joined by spot brazing with Cu-Ni-Sn-P brazing filler and cover plate.

  17. Infrared Brazing Zirconium using Two Silver Based Foils

    Institute of Scientific and Technical Information of China (English)

    Cheng-Han Lee; Ren-Kae Shiue


    Ag-based brazing foils,BAg-8 (72Ag-28Cu in wt%) and Ticusil(R) (68.8Ag-26.7Cu-4.5Tiin wt%) were selected to braze Zr.Interfacial AgCu4Zr,CuZr2 reaction layers and Ag-rich matrix dominate BAg-8 brazed joint,and fractograph after shear test shows ductile dimple fracture with plastic sliding marks.Ticusil~ joint brazed at 910℃ for 300 s is comprised of Cu9Zr11 and AgZr intermetallics,and fractograph after shear test displays brittle cleavage fracture.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  19. WELDING TORCH (United States)

    Correy, T.B.


    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)

  20. Optimization of weld bead geometry in laser welding with filler wire process using Taguchi’s approach (United States)

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


    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.

  1. 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 (United States)

    Saranath, K. M.; Ramji, M.


    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

  2. Brazing of copper to stainless steel with a low-silver-content brazing filler metal (United States)

    Fukikoshi, Tatsuya; Watanabe, Yūki; Miyazawa, Yasuyuki; Kanasaki, Fumio


    The brazing of copper to stainless steel (SUS304 JIS) was performed using a low- silver-content brazing filler metal, Ag-50Cu, under an Ar gas atmosphere with a conventional furnace, owing to the potential economic benefits of using low-silver-content filler metals. The brazeability of the low-silver-content brazing filler metal to copper and SUS304 was investigated. A good joint was obtained, and a drastic dissolution reaction occurred at the copper side. Molten BAg8 penetrated along the crystal grain boundary of the copper base metal when BAg8 was used as the filler metal. This was caused by the dissolution of Ni from the stainless steel into the molten filler metal. Ag-50Cu, which was investigated in this work, can be used instead of BAg8 filler metal.

  3. In Situ Synthesis of Al-Si-Cu Alloy During Brazing Process and Mechanical Property of Brazing Joint

    Directory of Open Access Journals (Sweden)

    LONG Wei-min


    Full Text Available The Al-Si-Cu alloy system is considered to be a promising choice of filler metal for aluminium alloys brazing due to its high strength and low melting point. The greatest obstacle is its lack of plastic forming ability and being difficult to be processed by conventional methods. This disadvantage is ascribed to the considerable amount of brittle CuAl2 intermetallic compound which forms when alloy composition is around the ternary eutectic point. In order to overcome this deficiency, authors of this article proposed to synthesize Al-Si-Cu filler metal by using in situ synthesis method, and the structure and properties of brazing joints were studied. The results show that AlSi alloy is used as the wrap layer, and CuAl alloy is used as the powder core in the composite brazing wire, the two alloys have similar melting points. The machinability of the composite brazing wire is much superior to the traditional Al-Si-Cu filler metal. During the induction brazing of 3A21 alloy, when using AlSi-CuAl composite filler wire, AlSi and CuAl alloys melt almost simultaneously, then after short time holding, Al-Si-Cu braze filler is obtained, the brazing seam has uniform composition and good bonding interface, also, the shearing strength of the brazing joints is higher than the joint brazed by conventional Al-Si-Cu filler metal.

  4. Primary Water Stress Corrosion Cracks in Nickel Alloy Dissimilar Metal Welds: Detection and Sizing Using Established and Emerging Nondestructive Examination Techniques

    Energy Technology Data Exchange (ETDEWEB)

    Braatz, Brett G.; Cumblidge, Stephen E.; Doctor, Steven R.; Prokofiev, Iouri


    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

  5. TIG-dressing of high strength butt welded connection - Part 2: physical testing and modelling

    NARCIS (Netherlands)

    Es, S.H.J. van; Kolstein, M.H.; Pijpers, R.J.M.; Bijlaard, F.S.K.


    Weld improvement techniques are aimed at reducing the notch effects of welds and generally focus on two aspects: a change of geometry of the weld toe and a change of the weld residual stresses. In this paper, fatigue tests are discussed, performed on butt welded specimens in steel grades ranging fro

  6. TIG-dressing of High Strength Butt Welded Connection. Part 2: Physical Testing and Modelling

    NARCIS (Netherlands)

    Van Es, S.H.J.; Kolstein, M.H.; Pijpers, R.J.M.; Bijlaard, F.S.K.


    Weld improvement techniques are aimed at reducing the notch effects of welds and generally focus on two aspects: a change of geometry of the weld toe and a change of the weld residual stresses. In this paper, fatigue tests are discussed, performed on butt welded specimens in steel grades ranging fro

  7. Characteristics of Extra Narrow Gap Weld of HSLA Steel Welded by Single-Seam per Layer Pulse Current GMA Weld Deposition (United States)

    Agrawal, B. P.; Ghosh, P. K.


    Butt weld joints are produced using pulse current gas metal arc welding process by employing the technique of centrally laid multi-pass single-seam per layer weld deposition in extra narrow groove of thick HSLA steel plates. The weld joints are prepared by using different combination of pulse parameters. The selection of parameter of pulse current gas metal arc welding is done considering a summarized influence of simultaneously interacting pulse parameters defined by a dimensionless hypothetical factor ϕ. The effect of diverse pulse parameters on the characteristics of weld has been studied. Weld joint is also prepared by using commonly used multi-pass multi-seam per layer weld deposition in conventional groove. The extra narrow gap weld joints have been found much superior to the weld joint prepared by multi-pass multi-seam per layer deposition in conventional groove with respect to its metallurgical characteristics and mechanical properties.

  8. Nanoparticle-Assisted Diffusion Brazing of Metal Microchannel Arrays: Nanoparticle Synthesis, Deposition, and Characterization (United States)

    Eluri, Ravindranadh T.

    sputtering a 1 microm thick layer of Cu before depositing a 5 nm thick film of AgNPs resulting in a lap shear strength of 45.3 +/- 0.2 MPa. In the middle section of this thesis, several techniques are investigated for the synthesis of sub 10 nm diameter nickel nanoparticles (NiNPs) to be used in the diffusion brazing of 316L stainless steel. The average NiNP size was varied from 9.2 nm to 3.9 nm based on the synthesis technique, solvent and reducing agent used. Conventional wet-chemical synthesis using NiCl2.6H2O in ethylene glycol (solvent) and N2 H4.H2O (reducing agent) resulted in the formation of 5.4 +/- 0.9 nm NiNPs. Continuous flow synthesis using a microchannel T-mixer (barrel diameter of 521microm) and a 10 second residence time of reactants in a bath temperature of 130ºC resulted in a particle size of with 5.3 +/- 1 nm. To make the synthesis safer and less energy intense, microwave heating was used along with less toxic Ni(CH3CO 2)2·4H2O (nickel salt), propylene glycol (solvent) and NaPH2O2 (reducing agent) yielding 3.9 +/- 0.8 nm diameter NiNPs. For the final section, nickel nanoparticles were synthesized using NiCl2.6H2O (nickel salt), de-ionized water (solvent), NaBH4 (co-reducing agent), N2H4.H 2O (reducing agent) and polyvinylpyrolidone (capping agent) yielding 4.2 +/- 0.6 nm NiNP. Several deposition techniques were investigated for controlling film thickness and uniformity in the diffusion brazing of 316L stainless steel (SS). Using in-house prepared NiNP and automated dispensing, a hermetic joint up to 70 psi (tested pressure) was obtained in 316L SS substrates under brazing conditions of 800ºC, 2 MPa and 30 min. Throughout the course of this thesis, techniques used for characterizing nanoparticles, films and joints included FT-IR, XRD, SEM, TEM, HRTEM, EDS, EPMA, DSC, mass spectrometry, and lap-shear testing.

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

  10. 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)


    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.

  11. 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


    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.

  12. Evolution of a Laser Hybrid Welding Map (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.

  13. 钨镍(W-Ni)的焊接性能及工艺%Welding Properties and Technique of Wolfram and Nickel

    Institute of Scientific and Technical Information of China (English)

    邓景泉; 张阳熠


    异种金属的有效连接在高新技术领域具有实际意义,采用电阻点焊方法焊接稀有金属钨片和镍丝.用SEM,HRTEM表征焊接接头的组织形貌,用拉伸试验机测定焊接件的抗剪切力.采用如下焊接工艺:第一阶段:预压力是100 N,使钨镍良好接触;第二阶段:保持预压力不变,施以预热电流1.1KA,400 ms,然后再施以焊接电流1.7KA,400 ms;第三阶段:保持100 N的电极压力60 ms;最后,撤去电极压力.HRTEM结果表明:钨镍之间通过高温原子扩散形成置换固溶体而形成有效的连接,且在钨镍界面上没有新相形成.SEM结果表明焊接接头的镍丝没有翘头,且边缘没有严重压扁现象.经上述工艺得到的焊接接头的抗剪切力约为40 N,符合焊接件技术要求.%Effective weldinrg of heterogeneity metals was of great pragmatic importance in modern hi-tech area.W plate and Ni thread were joined by using resistance spot-welding.SEM , HRTEM were used to characterize the microstructures of the welding-joint.The anti-shear forces of the welding-joint were messured with the tenaile experimental machine.The optimized welding technique was as folIows: the first stage pre-pressure 100 N; the second stage keeping pre-pressure, pre-heat current 1.1 kA, 400 ms and then welding current 1.7 kA, 400 ms; the third stage retaining pre-pressure for another 60 ms.The results of HRTEM showed that W and Ni were joined effectively through W and Ni atoms diffusion forming substitutional solid solution.There were no new phases or intermetallics between W and Ni on houndaries.SEM showed that the shape of the welding knot conformed to the technological requirements without severe deformation.The anti-shear force of the joint was about 40 N.

  14. 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:; 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


    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)

  15. Failure Assessment Diagram for Brazed 304 Stainless Steel Joints (United States)

    Flom, Yory


    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).

  16. Silver-palladium braze alloy recovered from masking materials (United States)

    Cierniak, R.; Colman, G.; De Carlo, F.


    Method for recovering powdered silver-palladium braze alloy from an acrylic spray binder and rubber masking adhesive used in spray brazing is devised. The process involves agitation and dissolution of masking materials and recovery of suspended precious metal particles on a filter.

  17. Brazing of stainless steel; Stainless ko no rozuke

    Energy Technology Data Exchange (ETDEWEB)

    Matsu, T.


    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.

  18. Reactive Boride Brazing on Low-Alloy Automotive Grade Steel (United States)

    Palanisamy, B.; Upadhyaya, A.


    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.

  19. 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)


    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)

  20. 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


    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.

  1. Next generation high productivity submerged arc welding


    LANGENOJA, MARKUS; Öhrvall Karlsson, Vincent


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

  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


    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. Fundamentals of evaluation and diagnostics of welded structures

    CERN Document Server

    Nedoseka, Anatoliy Yakovlevich


    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...

  4. 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


    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.

  5. Milestones in welding technology (United States)

    Dolby, Richard E.


    Sir Alan's PhD thesis describes his research into cracking during arc welding of armour steels. Throughout his career, he had a strong interest in defects of all types, how they formed in metallic structures and how the larger ones could be detected and sized by non-destructive techniques. He was also vitally concerned with how defects impacted on the engineering integrity of welded structures, particularly the risk of fracture in nuclear plant. This study presents a view of some of the major milestones in global welding technology that took place over the 60 or more years of Sir Alan's career and highlights those where he had a personal and direct involvement.

  6. 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


    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.

  7. Damage Tolerance Assessment of Friction Pull Plug Welds (United States)

    McGill, Preston; Burkholder, Jonathan


    Friction stir welding is a solid state welding process developed and patented by The Welding Institute in Cambridge, England. Friction stir welding has been implemented in the aerospace industry in the fabrication of longitudinal welds in pressurized cryogenic propellant tanks. As the industry looks to implement friction stir welding in circumferential welds in pressurized cryogenic propellant tanks, techniques to close out the termination hole associated with retracting the pin tool are being evaluated. Friction pull plug welding is under development as a one means of closing out the termination hole. A friction pull plug weld placed in a friction stir weld results in a non-homogenous weld joint where the initial weld, plug weld, their respective heat affected zones and the base metal all interact. The welded joint is a composite, plastically deformed material system with a complex residual stress field. In order to address damage tolerance concerns associated with friction plug welds in safety critical structures, such as propellant tanks, nondestructive inspection and proof testing may be required to screen hardware for mission critical defects. The efficacy of the nondestructive evaluation or the proof test is based on an assessment of the critical flaw size in the test or service environments. Test data relating residual strength capability to flaw size in two aluminum alloy friction plug weld configurations is presented.

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

    Directory of Open Access Journals (Sweden)

    Saritprava Sahoo


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

  9. Passive Visual Sensing in Automatic Arc Welding

    DEFF Research Database (Denmark)

    Liu, Jinchao

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

  10. Process Parameters Optimization for Friction Stir Welding of Pure Aluminium to Brass (CuZn30 using Taguchi Technique

    Directory of Open Access Journals (Sweden)

    Elfar O. M. R.


    Full Text Available In this research, the friction stir welding of dissimilar commercial pure aluminium and brass (CuZn30 plates was investigated and the process parameters were optimized using Taguchi L9 orthogonal array. The considered process parameters were the rotational speed, traverse speed and pin offset. The optimum setting was determined with reference to ultimate tensile strength of the joint. The predicted optimum value of ultimate tensile strength was confirmed by experimental run using optimum parameters. Analysis of variance revealed that traverse speed is the most significant factor in controlling the joint tensile strength and pin offset also plays a significant role. In this investigation, the optimum tensile strength is 50% of aluminium base metal. Metallographic examination revealed that intermetallic compounds were formed in the interface of the optimum joint where the tensile failure was observed to take place.

  11. Syllabus in Trade Welding. (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…



  13. ITER lip seal welding and cutting developments

    Energy Technology Data Exchange (ETDEWEB)

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


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

  14. Study on local vacuum electron beam welding of flange rim

    CERN Document Server

    He Cheng Dan; Ying Lei; Xu Qi Jin


    Local vacuum electron beam welding and its application prospect in military and civil industry are introduced. A home made local vacuum electron beam welding is completed. Its main technical parameters and key techniques are also presented

  15. 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


    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.

  16. Surface development of an aluminum brazing sheet during heating studied by XPEEM and XPS (United States)

    Rullik, L.; Bertram, F.; Niu, Y. R.; Evertsson, J.; Stenqvist, T.; Zakharov, A. A.; Mikkelsen, A.; Lundgren, E.


    X-ray photoelectron emission microscopy (XPEEM) was used in combination with other microscopic and spectroscopic techniques to follow the surface development of an aluminum brazing sheet during heating. The studied aluminum alloy sheet is a composite material designed for vacuum brazing. Its surface is covered with a native aluminum oxide film. Changes in the chemical state of the alloying elements and the composition of the surface layer were detected during heating to the melting temperature. It was found that Mg segregates to the surface upon heating, and the measurements indicate the formation of magnesium aluminate. During the heating the aluminum oxide as well as the silicon is observed to disappear from the surface. Our measurements is in agreement with previous studies observing a break-up of the oxide and the outflow of the braze cladding onto the surface, a process assisted by the Mg segregation and reaction with surface oxygen. This study also demonstrates how XPEEM can be utilized to study complex industrial materials.

  17. Control of Interfacial Reactivity Between ZrB2 and Ni-Based Brazing Alloys (United States)

    Valenza, F.; Muolo, M. L.; Passerone, A.; Cacciamani, G.; Artini, C.


    Transition metals diborides (Ti,Zr,Hf)B2 play a key role in applications where stability at extremely high temperatures and damage tolerance are required; however, much research has still to be done to optimize the joining of these materials to themselves or to other high-temperature materials. In this study, the reactivity at the solid-liquid interface between ZrB2 ceramics and Ni-based brazing alloys has been addressed; it is shown how the reactivity and the dissolution of the solid phase can be controlled and even suppressed by adjusting the brazing alloy composition on the basis of thermodynamic calculations. Wetting experiments on ZrB2 ceramics by Ni, Ni-B 17 at.%, and Ni-B 50 at.% were performed at 1500 and 1200 °C by the sessile drop technique. The obtained interfaces were characterized by optical microscopy and SEM-EDS, and interpreted by means of the ad hoc-calculated B-Ni-Zr ternary diagram. A correlation among microstructures, substrate dissolution, shape of the drops, spreading kinetics, and the phase diagram was found. The effect on the interfacial reactivity of Si3Ni4 used as a sintering aid and issues related to Si diffusion into the brazing alloy are discussed as well.

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

    Directory of Open Access Journals (Sweden)

    Jean S. Pimenta


    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.

  19. Hybrid manufacturing processes for fusion welding and friction stir welding of aerospace grade aluminum alloys (United States)

    Gegesky, Megan Alexandra

    Friction stir welding and processing can provide for joints in aerospace grade aluminum alloys that have preferable material properties as compared to fusion welding techniques. Aerospace grade aluminum alloys such as AA2024-T3 and AA7075-T6 are considered non-weldable by traditional fusion welding techniques. Improved mechanical properties over previously used techniques are usually preferable for aerospace applications. Therefore, by combining traditional fusion welding and friction stir processing techniques, it could be plausible to create more difficult geometries in manufactured parts instead of using traditional techniques. While this combination of fusion welding and friction stir processing is not a new technology, its introduction to aerospace grade aluminum alloys as well as non-weldable alloys, is new. This is brought about by a lowered required clamping force required by adding a fusion weld before a friction stir processing technique. The changes in properties associated with joining techniques include: microstructural changes, changes in hardness, tensile strength, and corrosion resistance. This thesis illustrates these changes for the non-weldable AA2024-T351 and AA7075-T651 as well as the weldable alloy AA5052-H32. The microhardness, tensile strength and corrosion resistance of the four processing states: base material, fusion welded material, friction stir welded material, and friction stir processed fusion welded material is studied. The plausibility of this hybrid process for the three different materials is characterized, as well as plausible applications for this joining technique.

  20. Nondestructive Ultrasonic Inspection of Friction Stir Welds (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.

  1. Welded Kimberlite? (United States)

    van Straaten, B. I.; Kopylova, M. G.; Russell, J. K.; Scott Smith, B. H.


    Welding of pyroclastic deposits generally involves the sintering of hot glassy vesicular particles and requires the presence of a load and/or high temperatures. Welding can occur on various scales as observed in large welded pyroclastic flows, in small-volume agglutinated spatter rims, or as in coalesced clastogenic lava flows. In all these examples welding occurs mainly by reduction or elimination of porosity within the vesicular clasts and/or inter-clast pore space. The end result of welding in pyroclastic deposits is to produce dense, massive, coherent deposits. Here, we present a possible new end-member of the welding process: welding of non- vesicular pyroclasts in intra-crater kimberlite deposits. Kimberlite melt is a low-viscosity liquid carrying abundant crystals. Because of this, kimberlite eruptions generally produce non-vesicular pyroclasts. During welding, these pyroclast cannot deform by volume reduction to form typical fiamme. As a result, welding and compaction in kimberlites proceeds via the reduction of inter-clast pore space alone. The lack of porous pyroclasts limits the maximum amount of volumetric strain within pyroclastic kimberlite deposits to about 30%. This value is substantially lower than the limiting values for welding of more common felsic pyroclastic flows. The lower limit for volumetric strain in welded kimberlite deposits severely restricts the development of a fabric. In addition, pyroclastic kimberlite deposits commonly feature equant-shaped pyroclasts, and equant-shaped crystals. This, in turn, limits the visibility of the results of compaction and pore space reduction, as there are few deformable markers and elongate rigid markers that are able to record the strain during compaction. These features, together with the low viscosity of kimberlite magma and the stratigraphic position of these kimberlite deposits within the upper reaches of the volcanic conduit, call for careful interpretation of coherent-looking rocks in these

  2. Friction Stir Welding of Tapered Thickness Welds Using an Adjustable Pin Tool (United States)

    Adams, Glynn; Venable, Richard; Lawless, Kirby


    Friction stir welding (FSW) can be used for joining weld lands that vary in thickness along the length of the weld. An adjustable pin tool mechanism can be used to accomplish this in a single-pass, full-penetration weld by providing for precise changes in the pin length relative to the shoulder face during the weld process. The difficulty with this approach is in accurately adjusting the pin length to provide a consistent penetration ligament throughout the weld. The weld technique, control system, and instrumentation must account for mechanical and thermal compliances of the tooling system to conduct tapered welds successfully. In this study, a combination of static and in-situ measurements, as well as active control, is used to locate the pin accurately and maintain the desired penetration ligament. Frictional forces at the pin/shoulder interface were a source of error that affected accurate pin position. A traditional FSW pin tool design that requires a lead angle was used to join butt weld configurations that included both constant thickness and tapered sections. The pitch axis of the tooling was fixed throughout the weld; therefore, the effective lead angle in the tapered sections was restricted to within the tolerances allowed by the pin tool design. The sensitivity of the FSW process to factors such as thickness offset, joint gap, centerline offset, and taper transition offset were also studied. The joint gap and the thickness offset demonstrated the most adverse affects on the weld quality. Two separate tooling configurations were used to conduct tapered thickness welds successfully. The weld configurations included sections in which the thickness decreased along the weld, as well as sections in which the thickness increased along the weld. The data presented here include weld metallography, strength data, and process load data.


    Directory of Open Access Journals (Sweden)

    Kozachenko A. D.


    Full Text Available Brazes with increased viscosity are needed for brazing of abrasive diamond tools with working surface of complex contoured shape. It’s known that high viscosity is a property of composite brazes consisting of fusible matrix and refractory filler that is not melting during brazing. Goal of the work is to research the influence of refractory fillers on the process of composite brazing of diamond-abrasive tools and on that basis discover the optimal composition of braze. Composite brazes Sn-Cu-Co were researched in the work. It is determined that at least 26-28% (by mass of cobalt powder should be included in brazes for giving the braze Sn-Cu-Co necessary viscosity and for creation of uniform diamond-comprising layers with thickness up to 2.5 mm on the vertical layers and sharp edges of tools. It is determined that solid-state sintering of powders on the initial stage of heating the composite braze leads to emerging of internal stresses and forming cracks. Inert additions that prevent solid-state sintering should be include in braze to prevent cracking. Optimal inert addition for brazes Sn-Cu-Co is the tungsten powder. Minimum content of tungsten needed to prevent cracking is 6% (by mass. Optimal content of components in composition braze for brazing shaped diamond-abrasive tools is (% by mass: 30 Co, 20 Sn, 43 Cu, 7 W

  4. Issues of low activation brazing of SiC f/SiC composites by using alloys without free silicon (United States)

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


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  6. Differences between Laser and Arc Welding of HSS Steels (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.

  7. Pulsed Magnetic Welding for Advanced Core and Cladding Steel

    Energy Technology Data Exchange (ETDEWEB)

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


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

  8. 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)


    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.

  9. Friction Stir Spot Welding of Advanced High Strength Steels

    Energy Technology Data Exchange (ETDEWEB)

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


    Friction stir spot welding techniques were developed to successfully join several advanced high strength steels. Two distinct tool materials were evaluated to determine the effect of tool materials on the process parameters and joint properties. Welds were characterized primarily via lap shear, microhardness, and optical microscopy. Friction stir spot welds were compared to the resistance spot welds in similar strength alloys by using the AWS standard for resistance spot welding high strength steels. As further comparison, a primitive cost comparison between the two joining processes was developed, which included an evaluation of the future cost prospects of friction stir spot welding in advanced high strength steels.

  10. Evaluation of the Low Heat Input Process for Weld Repair of Nickel-Base Superalloys (United States)

    Durocher, J.; Richards, N. L.


    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.


    Directory of Open Access Journals (Sweden)

    Dan NIŢOI


    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.

  12. 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


    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.

  13. Control of vacuum induction brazing system for sealing of instrumentation feed-through

    Energy Technology Data Exchange (ETDEWEB)

    Sung Ho Ahn; Jintae Hong; Chang Young Joung; Ka Hae Kim; Sung Ho Heo [Korea Atomic Energy Research Institute (Korea, Republic of)


    The integrity of instrumentation cables is an important performance parameter in addition to the sealing performance in the brazing process. An accurate brazing control was developed for the brazing of the instrumentation feed-through in the vacuum induction brazing system in this paper. The experimental results show that the accurate brazing temperature control performance is achieved by the developed control scheme. Consequently, the sealing performances of the instrumentation feed-through and the integrities of the instrumentation cables were satisfied after brazing. (authors)

  14. Reactive Brazing of Carbon-Carbon Composites to Titanium (United States)

    Shpargel, Tarah; Singh, M.; Morscher, Gregory; Asthana, Rajiv


    The Ti-metal/C-C composite joints were formed by reactive brazing with three commercial brazes, namely, Cu-ABA, TiCuNi, and TiCuSil. 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.

  15. Active Metal Brazing of Carbon-Carbon Composites to Titanium (United States)

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


    The Ti-metal/C-C composite joints were formed by reactive brazing with three commercial brazes, namely, Cu-ABA, TiCuNi, and TiCuSil. 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 which led to good wetting, spreading, and metallurgical bond formation via interdiffusion.

  16. Residual stresses in welded plates (United States)

    Bernstein, Edward L.


    The purpose of this project was to develop a simple model which could be used to study residual stress. The mechanism that results in residual stresses in the welding process starts with the deposition of molten weld metal which heats the immediately adjacent material. After solidification of weld material, normal thermal shrinkage is resisted by the adjacent, cooler material. When the thermal strain exceeds the elastic strain corresponding to the yield point stress, the stress level is limited by this value, which decreases with increasing temperature. Cooling then causes elastic unloading which is restrained by the adjoining material. Permanent plastic strain occurs, and tension is caused in the region immediately adjacent to the weld material. Compression arises in the metal farther from the weld in order to maintain overall static equilibrium. Subsequent repair welds may add to the level of residual stresses. The level of residual stress is related to the onset of fracture during welding. Thus, it is of great importance to be able to predict the level of residual stresses remaining after a weld procedure, and to determine the factors, such as weld speed, temperature, direction, and number of passes, which may affect the magnitude of remaining residual stress. It was hoped to use traditional analytical modeling techniques so that it would be easier to comprehend the effect of these variables on the resulting stress. This approach was chosen in place of finite element methods so as to facilitate the understanding of the physical processes. The accuracy of the results was checked with some existing experimental studies giving residual stress levels found from x-ray diffraction measurements.

  17. Deformation control technique for welding stainless steel sheet expansion tank%不锈钢薄板溢流箱焊接变形控制工艺

    Institute of Scientific and Technical Information of China (English)

    石秋红; 张勤


    某公司建设工程中的304材质不锈钢薄板溢流箱有较大的焊接变形倾向,而产品对变形后的尺寸偏差要求非常严格.通过分析304材质的焊接性,对比不同焊接方法,选用了焊接变形较小的药芯焊丝CO2气体保护焊,并合理选用焊接材料与焊接工艺参数,根据溢流箱结构特点安排合适的焊缝焊接顺序.焊接效果证明此焊接工艺有效解决了不锈钢薄板溢流箱的焊接变形难题,降低了生产成本,提高了生产效率,满足了工程质量要求.%The production of X company's construction project has a quite strict dimensional deviation criterion after deformation. However, type 304 stainless sheet steel overflow tank has significant tendency of weld deformation. Therefore, in this paper, it performed analysis on the weld ability of type 304, and comparison among different welding methods. It chose flux-cored wire co2 shield welding which of little welding deformation, and chose reasonable welding parameters and materials. In addition, it also arranged suitable weld sequence in accordance with the structural features of overflow tank. The welding effect proved that this welding method can effectively resolve the welding deformation problems of stainless sheet steel overflow tank, reduced cost of production, improved production efficiency and met project quality requirements.

  18. Welding Curtains (United States)


    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.

  19. Effect of composition of titanium in silver-copper-titanium braze alloy on dissimilar laser brazing of binder-less cubic boron nitride and tungsten carbide (United States)

    Sechi, Yoshihisa; Nagatsuka, Kimiaki; Nakata, Kazuhiro


    Laser brazing with Ti as an active element in silver-copper alloy braze metal has been carried out for binder-less cubic boron nitride and tungsten carbide, using silver-copper- titanium braze alloys with titanium content that varied between 0.28 mass% and 1.68 mass%. Observations of the interface using electron probe microanalysis and scanning acoustic microscopy show that efficient interface adhesion between binder-less cubic boron nitride and the silver-copper-titanium braze alloy was achieved for the braze with a titanium content of 0. 28 mass%.

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

    Directory of Open Access Journals (Sweden)

    Zorc, Borut


    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.


    Institute of Scientific and Technical Information of China (English)

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


    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.

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

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

    Institute of Scientific and Technical Information of China (English)


    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.

  4. Annular beam shaping system for advanced 3D laser brazing (United States)

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


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Foust, H.D.


    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.

  6. Brazing open cell reticulated copper foam to stainless steel tubing with vacuum furnace brazed gold/indium alloy plating (United States)

    Howard, Stanley R.; Korinko, Paul S.


    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.

  7. Improved design bases of welded joints in seawater

    DEFF Research Database (Denmark)

    Ólafsson, Ólafur Magnús

    The presented work aims to investigate and establish a precise, thorough and detailed database from series of experimental testing of submerged arc welded, SAW, specimens of various thicknesses typically applied in offshore structures and foundations. Additionally, the testing was performed in two...... welded joints were thereafter compared directly to the traditional SAW specimens in order to investigate the two different welding techniques. The laser hybrid welding technique offers great potential in lowering the cost of energy associated with offshore structures....... different environments, i.e. under in-air conditions and in a corrosion environment. Welded structures of all sizes and shapes exhibit fatigue failure primarily in the welded region, rather than in the base material, due to imperfections and flaws relating to the welding procedure. The welded region has...


    Institute of Scientific and Technical Information of China (English)

    LI Junyue; XUE Haitao; LI Huan; SONG Yonglun


    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.

  9. Marangoni driven free surface flows in liquid weld pools

    NARCIS (Netherlands)

    Saldi, Z.S.


    Extending the weldability of novel materials, and improving the weld quality by tailoring weld microstructures are key factors to obtain the welding techniques demanded in the modern manufacturing industries. This can be done, for example, by feeding chemical elements from a consumable wire into the

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

    Institute of Scientific and Technical Information of China (English)


    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.

  11. ARc Welding (Industrial Processing Series). (United States)


  12. 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


    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.

  13. Resistance Welding of Thermoplastic Composites: Process and Performance


    Shi, H.


    Compared to thermoset composites, thermoplastic composites are drawing more and more attention by aircraft industries not only due to their excellent material properties but also due to their potentials to reduce cycle time and structure cost by using low-cost manufacturing technologies such as welding. Resistance welding has been regarded as one of the most promising welding techniques owing to the low energy consumption, simplicity of welding operation and capability for scaling up. Previou...

  14. Welding of Aluminum Alloys to Steels: An Overview (United States)


    and deformations are a few examples of the unwanted consequences which somehow would lead to brittle fracture , fatigue fracture , shape instability...UNCLASSIFIED 7 UNCLASSIFIED 2.1. Fusion welding methods 2.1.1. Gas metal arc (MIG) welding and tungsten inert gas (TIG) welding techniques...coating had imperfect influence to improve the appearance of the weld bead and there were many micro-cracks in the middle of the bond zone. The fracture

  15. Investigation of high-frequency pipe welding (United States)

    Konovalov, Nikolai A.; Lakhno, Nikolay I.; Gushchin, A. G.; Putryk, N. D.; Kovalenko, Vladimir I.; Galkina, V. A.; Veselovsky, Vladimir B.; Furmanov, Valeri B.; Kovika, Nikolai D.; Novikov, Leonid V.; Shcherbina, V. N.


    For investigation of a pipe welding process at high-frequency heating aimed at increasing of pipe quality and decreasing of spoilage, the use of high-speed recording and TV-technique is considered to be effective. The authors have created a visual inspection system for pipe welding process studies at a tube mill of the Novomoskovsk Pipe Plant.

  16. 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


    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.

  17. In-process oxidation protection in fluxless brazing or diffusion bonding of aluminum alloys (United States)

    Okelly, K. P.; Featherston, A. B.


    Aluminum is cleaned of its oxide coating and is sealed immediately with polymeric material which makes it suitable for fluxless brazing or diffusion bonding. Time involved between cleaning and brazing is no longer critical factor.

  18. 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


    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.

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

    Directory of Open Access Journals (Sweden)

    Koray Yurtisik


    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.

  20. 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


    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.

  1. 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


    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。

  2. Manufacturing of 25 mm heavy-wall linepipe using the high frequency induction (HFI) welding technique, a challenge for a pipe manufacturer

    Energy Technology Data Exchange (ETDEWEB)

    Tazedakis, Athanasios S.; Voudouris, Nikolaos G. [Corinth Pipeworks Thisvi Plant, Viotia, (Greece); Musslewhite, Mike [CPW America, Houston, TX, (United States)


    High frequency inductive welding is widely used in the pipeline industry to process longitudinally welded pipes from hot-rolled strip. Increased demand has caused CPW-Thisvi to expand HFI process limits from 20.6 mm to 25 mm for high grade applications. This paper reports on the development of this process and presents the technical specifications. The technology used to make possible the use of HFI up to X60 are described in detail. The theoretical analysis was performed using a finite element model. It was used to determine the new forming and welding parameters required to optimize production. The CPW also designed specifically heavy wall weld seam ultrasonic inspection for HFI pipes. Results showed properties which were homogenous and satisfied API 5L requirements. This study also showed the interesting potential of micro-alloyed steels.

  3. Vacuum brazing of electroless Ni-P alloy-coated SiCp/Al composites using aluminum-based filler metal foil (United States)

    Wang, Peng; Xu, Dongxia; Niu, Jitai


    Using rapidly cooled (Al-10Si-20Cu-0.05Ce)-1Ti (wt%) foil as filler metal, the research obtained high-performance joints of electroless Ni-P alloy-coated aluminum matrix composites with high SiC particle content (60 vol%, SiCp/Al-MMCs). The effect of brazing process on joint properties and the formation of Al-Ni and Al-Cu-Ni intermetallic compounds were investigated, respectively. Due to the presence of Ni-P alloy coating, the wettability of liquid filler metal on the composites was improved obviously and its contact angle was only 21°. The formation of Al3Ni2 and Al3(CuNi)2 intermetallic compounds indicated that well metallurgical bonding occurred along the 6063Al matrix alloy/Ni-P alloy layer/filler metal foil interfaces by mutual diffusion and dissolution. And the joint shear strength increased with increasing the brazing temperature from 838 to 843 K or prolonging the soaking time from 15 to 35 min, while it decreased a lot because of corrosion occurring in the 6063Al matrix at high brazing temperature of 848 K. Sound joints with maximum shear strength of 112.5 MPa were obtained at 843 K for soaking time of 35 min. In this research, the beneficial effect of surface metallization by Ni-P alloy deposits on improving wettability on SiCp/Al-MMCs was demonstrated, and capable welding parameters were broadened as well.

  4. Review on electromagnetic welding of dissimilar materials (United States)

    Shanthala, K.; Sreenivasa, T. N.


    Electromagnetic welding (EMW) is a highspeed joining technique that is used to join similar or dissimilar metals, as well as metals to non-metals. This technique uses electromagnetic force to mainly join conductive materials. Unlike conventional joining processes, the weld interface does not melt, thus keeping the material properties intact. Extremely high velocity and strain rate involved in the process facilitate extending the EMW technique for joining several materials. In this paper, the research and progress in electromagnetic welding are reviewed from various perspectives to provide a basis for further research.

  5. Laser based spot weld characterization (United States)

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


    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.

  6. Contamination and solid state welds.

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Bernice E.


    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.

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

    NARCIS (Netherlands)

    Wittebrood, A.J.


    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

  8. Effect of Filler Composition on the Brazing of Alumina to Copper Using Ultrasonic Wave

    Institute of Scientific and Technical Information of China (English)

    Khalid M. HAFEZ; Masaaki NAKA


    An ultrasonic wave was applied during brazing of alumina to Cu. First alumina was metallized by applying ultrasonicwave in braze bath. Then the metallized alumina was brazed with Cu using the same filler alloy. The filler used wereZn-Al alloys and Zn-Sn A

  9. Double global optimum genetic algorithm-particle swarm optimization-based welding robot path planning (United States)

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


    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.

  10. 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


    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.

  11. Seam Tracking Technology for Hyperbaric Underwater Welding

    Institute of Scientific and Technical Information of China (English)

    JIAO Xiangdong; YANG Yongyong; ZHOU Canfeng


    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.

  12. Numerical simulation of friction stir welding

    Directory of Open Access Journals (Sweden)

    Mijajlović Miroslav


    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

  13. Rapid Fabrication Techniques for Liquid Rocket Channel Wall Nozzles (United States)

    Gradl, Paul R.


    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.

  14. Advanced Laser Transmission Welding Strategies for Fibre Reinforced Thermoplastics (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.

  15. Friction Stir Welding (United States)

    Nunes, Arthur C., Jr.


    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.

  16. Microstructures of beta-titanium orthodontic wires joined by infrared brazing. (United States)

    Iijima, Masahiro; Brantley, William A; Kawashima, Isao; Baba, Naoki; Alapati, Satish B; Yuasa, Toshihiro; Ohno, Hiroki; Mizoguchi, Itaru


    The microstructures and interdiffusion in brazed beta-titanium orthodontic wires were investigated by scanning electron microscopy and electron probe microanalysis, respectively. Beta-titanium wire (Ti-11Mo-6Zr-4Sn) with cross-section dimensions of 0.032 in. x 0.032 in., titanium-based braze alloy (Ti-30Ni-20Cu), and silver-based braze alloy (Ag-22Cu-17Zn-5Sn) were selected for the study. Brazing was performed using infrared radiation (RS-1) under an argon atmosphere. Specimens were etched with two solutions (2.5% HF + 2.5% HNO(3) + 95% H(2)O; 25% HN(4)OH + 30% H(2)O(2) + 45%H(2)O). It was found that the silver-based braze alloy has a eutectic structure. In the diffusion layer between the beta-titanium wire and this silver-based braze alloy, Cu and Ti were enriched on the wire side, and Sn and Ti were enriched on the braze alloy side. The titanium-based braze alloy has a dendritic structure. Beta-titanium wire specimens brazed with the titanium-based braze alloy had a thicker intermediate area compared to the silver alloy; Ti in the diffusion layer had an irregular concentration gradient, and the braze alloy side had higher Ti concentration. The original microstructure of the beta-titanium wire was not altered with the use of either braze alloy. Infrared brazing of beta-titanium orthodontic wire is acceptable for clinical use, since the wire microstructure did not deteriorate with either the titanium-based or silver-based braze alloy. The differing microstructures of the joint regions for the two braze alloys suggest that the joint strengths may also differ.

  17. 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


    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.

  18. Radioisotope tracer studies in the NASA Skylab ethothermic brazing experiment M-552 (United States)

    Braski, D. N.; Adair, H. L.; Kobisk, E. H.


    The first use of radioisotope tracer for mapping flow patterns during brazing of metal components in a space environment (near-zero gravity) proved successful. A nickel ferrule was brazed to a nickel tube with Lithobraze BT (71.8% Ag, 28% Cu, 0.2% Li) which contained a trace amount of radioactive Ag-110. Mapping of the flow of the braze alloy in the annulus formed between the tube and the concentric ferrule was determined by counting the radiation intensity as a function of position in the braze joint. Significant information concerning the thermal history of the braze was determined.

  19. An Approach to Maximize Weld Penetration During TIG Welding of P91 Steel Plates by Utilizing Image Processing and Taguchi Orthogonal Array (United States)

    Singh, Akhilesh Kumar; Debnath, Tapas; Dey, Vidyut; Rai, Ram Naresh


    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.

  20. A review of oxide, silicon nitride, and silicon carbide brazing

    Energy Technology Data Exchange (ETDEWEB)

    Santella, M.L.; Moorhead, A.J.


    There is growing interest in using ceramics for structural applications, many of which require the fabrication of components with complicated shapes. Normal ceramic processing methods restrict the shapes into which these materials can be produced, but ceramic joining technology can be used to overcome many of these limitations, and also offers the possibility for improving the reliability of ceramic components. One method of joining ceramics is by brazing. The metallic alloys used for bonding must wet and adhere to the ceramic surfaces without excessive reaction. Alumina, partially stabilized zirconia, and silicon nitride have high ionic character to their chemical bonds and are difficult to wet. Alloys for brazing these materials must be formulated to overcome this problem. Silicon carbide, which has some metallic characteristics, reacts excessively with many alloys, and forms joints of low mechanical strength. The brazing characteristics of these three types of ceramics, and residual stresses in ceramic-to-metal joints are briefly discussed.

  1. Laser welding of stainless steel weld filler metals at high cooling rates

    Energy Technology Data Exchange (ETDEWEB)

    Vitek, J.M.; David, S.A.


    Several stainless steels were laser welded under conditions resulting in high cooling rates of the welds. Significant changes in the microstructures, compared to those produced by conventional welding techniques, were found. For alloys 304, 308, 309, 316 and 347, a general decrease in ferrite content with increasing cooling rate was found. For three alloys (304, 308, 347), a fully austenitic structure was obtained at the highest cooling rates. For alloys 312 and 446, the high cooling rates retarded the formation of austenite, resulting in higher ferrite contents and fully ferritic structures at the highest cooling rates. Only for alloy 310 was the microstructure after laser welding comparable to that found after conventional welding. The results are discussed in terms of their impact on the Schaeffler diagram and its applicability to laser welding. 11 refs., 7 figs.

  2. 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...

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

    Directory of Open Access Journals (Sweden)

    Z. Mirski


    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Filacchioni, G. E-mail:; Montanari, R.; Tata, M.E.; Pilloni, L


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

  5. Introduction to Welding. (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.…

  6. Distortion Control during Welding

    NARCIS (Netherlands)

    Akbari Pazooki, A.M.


    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

  7. 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)


    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.

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

    Indian Academy of Sciences (India)


    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.

  9. Brazing diamond grits onto a steel substrate using copper alloys as the filler metals (United States)

    Chen, S.-M.; Lin, S.-T.


    Surface-set diamond tools were fabricated by an active metal brazing process, using bronze (Cu-8.9Sn) powder and 316L stainless steel powder mixed to various ratios as the braze filler metals. The diamond grits were brazed onto a steel substrate at 1050 °C for 30 min in a dry hydrogen atmosphere. After brazing practice, an intermediate layer rich in chromium formed between the braze filler metal and diamond. A braze filler metal composed of 70 wt % bronze powder and 30 wt % stainless steel powder was found to be optimum in that the diamond grits were strongly impregnated in the filler metal by both mechanical and chemical types of holding. The diamond tools thus fabricated performed better than conventional nickel-plated diamond tools. In service, the braze filler metal wore at almost the same rate as the diamond grits, and no pullout of diamond grits or peeling of the filler metal layer took place.

  10. Numerical simulation of filler metal droplets spreading in laser brazing (United States)

    Chen, Yanbin; Feng, Xiaosong; Li, Liqun


    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. Computational simulations and experimental validation of a furnace brazing process

    Energy Technology Data Exchange (ETDEWEB)

    Hosking, F.M.; Gianoulakis, S.E.; Malizia, L.A.


    Modeling of a furnace brazing process is described. The computational tools predict the thermal response of loaded hardware in a hydrogen brazing furnace to programmed furnace profiles. Experiments were conducted to validate the model and resolve computational uncertainties. Critical boundary conditions that affect materials and processing response to the furnace environment were determined. {open_quotes}Global{close_quotes} and local issues (i.e., at the furnace/hardware and joint levels, respectively) are discussed. The ability to accurately simulate and control furnace conditions is examined.

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

    Directory of Open Access Journals (Sweden)

    S. Muthuraman


    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.

  13. 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


    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.

  14. Development of a Cu-Sn based brazing system with a low brazing and a high remelting temperature (United States)

    Schmieding, M.; Holländer, U.; Möhwald, K.


    Objective of the project presented is the development of a joining process for hot working steel components at low brazing temperatures leading to a bond with a much higher remelting temperature. This basically is achieved by the use of a Cu-Sn melt spinning foil combined with a pure Cu foil. During brazing, the Sn content of the foil is decreased by diffusion of Sn into the additional Cu resulting in a homogenious joint with a increased remelting temperature of the filler metal. Within this project specimens were brazed and diffusion annealed in a vacuum furnace at 850 °C varying the processing times (0 – 10 h). The samples prepared were studied metallographically and diffusion profiles of Sn were recorded using EDX line scans. The results are discussed in view of further investigations and envisaged applications.


    Institute of Scientific and Technical Information of China (English)

    L.X. Zhang; J.C. Feng; Z.R. Li; H.J. Liu


    The brazing of TiC cermet to iron was carried out at 1223K for 5-20min using Ag-Cu-Zn filler metal. The formation phase and interface structure of the joints were investigated by electron probe microanalysis (EPMA), scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the joint strength was tested by shearing method. The results showed: there occurred three new formation phases, Cu(s.s), FeNi and Ag(s.s) in TiC cermet/iron joint. The interface structure was expressed as TiC cermet/Cu(s.s)+FeNi/Ag(s.s)+a little Cu(s.s)+a little FeNi/Cu(s.s)+ FeNi/iron. With brazing time increasing, there appeared highest shear strength of the joints, the value of which was up to 252.2MPa when brazing time was 10min.

  16. Monte Carlo Simulation of Alloy Design Techniques: Fracture and Welding Studied Using the BFS Method for Alloys (United States)

    Bozzolo, Guillermo H.; Good, Brian; Noebe, Ronald D.; Honecy, Frank; Abel, Phillip


    Large-scale simulations of dynamic processes at the atomic level have developed into one of the main areas of work in computational materials science. Until recently, severe computational restrictions, as well as the lack of accurate methods for calculating the energetics, resulted in slower growth in the area than that required by current alloy design programs. The Computational Materials Group at the NASA Lewis Research Center is devoted to the development of powerful, accurate, economical tools to aid in alloy design. These include the BFS (Bozzolo, Ferrante, and Smith) method for alloys (ref. 1) and the development of dedicated software for large-scale simulations based on Monte Carlo- Metropolis numerical techniques, as well as state-of-the-art visualization methods. Our previous effort linking theoretical and computational modeling resulted in the successful prediction of the microstructure of a five-element intermetallic alloy, in excellent agreement with experimental results (refs. 2 and 3). This effort also produced a complete description of the role of alloying additions in intermetallic binary, ternary, and higher order alloys (ref. 4).

  17. “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


    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

  18. Tool Forces Developed During Friction Stir Welding (United States)

    Melendez, M.; Tang, W.; Schmidt, C.; McClure, J. C.; Nunes, A. C.; Murr, L. E.


    This paper will describe a technique for measuring the various forces and the torque that exist on the Friction Stir Welding pin tool. Results for various plunge depths, weld speeds, rotational speed, and tool configurations will be presented. Welds made on 6061 aluminum with typical welding conditions require a downward force of 2800 lbs. (12.5 kN) a longitudinal force in the direction of motion of 300 lbs (1.33 kN), a transverse force in the omega x v direction of 30 lbs (135 N). Aluminum 2195 under typical weld conditions requires a downward force of 3100 lbs. (1.38 kN), a longitudinal force of 920 lbs. (4.1 kN), and a transverse force of 45 lbs. (200 N) in the omega x v direction.

  19. Characterization of the Micro-Welding Process for Repair of Nickel Base Superalloys (United States)

    Durocher, J.; Richards, N. L.


    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.

  20. Welding of Prosthetic Alloys

    Directory of Open Access Journals (Sweden)

    Wojciechowska M.


    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.

  1. Inspection of thick welded joints using laser-ultrasonic SAFT. (United States)

    Lévesque, D; Asaumi, Y; Lord, M; Bescond, C; Hatanaka, H; Tagami, M; Monchalin, J-P


    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.

  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)


    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. Microstructure modeling in weld metal

    Energy Technology Data Exchange (ETDEWEB)

    David, S.A.; Babu, S.S.


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

  4. High frequency welded (ERW) casing

    Energy Technology Data Exchange (ETDEWEB)

    Duisberg, J. (Hoesch Roehrenwerke A.G., Hamm (Germany, F.R.))


    Due to the up-to-date standard in welding and testing techniques, the significance of ERW-casing is growing rapidly. The basic items of ERW-pipe are explained in detail. The forming mechanism, the high frequency welding by induction and contact welding processes is explained in detail as well as destructive and non-destructive testing methods. Finishing the ends as threading, thread control (gauging), power tight connection, pressure test and final quality control are rounding up the picture of the production of ERW-casing. Last but not least the test results from the joint strength- and collapse tests which are of outstanding interest for casings, are compared with API requirements in order to demonstrate compliance with API requirements.

  5. 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


    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.

  6. Research on Brazability of SiC Particle Reinforced Aluminium-based Composite Prepared by Vacuum Brazing Process%SiC颗粒增强铝基复合材料的真空钎焊性研究

    Institute of Scientific and Technical Information of China (English)

    徐冬霞; 陈龙; 牛济泰; 薛行雁; 孙华为


    选用Pb80Sn20钎料,对体积分数20%的SiCP/A356复合材料进行真空钎焊,分析了表面镀镍和不镀镍对其真空钎焊性的影响,并通过金相显微、能谱分析等手段研究了保温时间对其钎焊接头组织的影响.研究结果表明:体积分数20%的SiCdA356复合材料表面不镀镍进行钎焊时,焊接性很差,镀镍后焊接性显著提高;对比6、8和10 min保温时间下钎焊接头硬度,8min保温时间最好.%Using Pb80Sn20 alloy as filler metal, SKVA356 composite containing 20% (volume fraction) SiC was brazed by vacuum brazing process. The influences on the brazability of the composite were analyzed after nickel chemical-plating on the surface of composite and without nickel chemical-plating process. The effects of holding time on the microstructure of the brazed joints of the composite were studied by metallographic microscope, SEM and energy spectrum analysis. The results show that the nickel plating on the surface of the composite can improve the brazability of SiCp/A356 composite, while the inferior brazability is demonstrated if the surface of the composite without nickel plating process. The hardness of the welded joints which are brazed at holding time for 6 min, 8 min and 10 min was contrasted. The hardness of the weld seam region is highest when the holding time is 8 min.

  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


    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. 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


    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.

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

    NARCIS (Netherlands)

    Norouzi Afshar, F.


    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

  10. Welded solar cell interconnection (United States)

    Stofel, E. J.; Browne, E. R.; Meese, R. A.; Vendura, G. J.


    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.

  11. Low temperature friction stir welding of P91 steel

    Directory of Open Access Journals (Sweden)

    Prasad Rao Kalvala


    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.

  12. 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


    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.

  13. Microgalvanic Corrosion Behavior of Cu-Ag Active Braze Alloys Investigated with SKPFM

    Directory of Open Access Journals (Sweden)

    Armen Kvryan


    Full Text Available The nature of microgalvanic couple driven corrosion of brazed joints was investigated. 316L stainless steel samples were joined using Cu-Ag-Ti and Cu-Ag-In-Ti braze alloys. Phase and elemental composition across each braze and parent metal interface was characterized and scanning Kelvin probe force microscopy (SKPFM was used to map the Volta potential differences. Co-localization of SKPFM with Energy Dispersive Spectroscopy (EDS measurements enabled spatially resolved correlation of potential differences with composition and subsequent galvanic corrosion behavior. Following exposure to the aggressive solution, corrosion damage morphology was characterized to determine the mode of attack and likely initiation areas. When exposed to 0.6 M NaCl, corrosion occurred at the braze-316L interface preceded by preferential dissolution of the Cu-rich phase within the braze alloy. Braze corrosion was driven by galvanic couples between the braze alloys and stainless steel as well as between different phases within the braze microstructure. Microgalvanic corrosion between phases of the braze alloys was investigated via SKPFM to determine how corrosion of the brazed joints developed.

  14. Split-body Processing and Fabrication Weld Manufacturing Technique of Super-long Coal Leveling Bar%超长平煤杆的分体加工组焊制造工艺技术

    Institute of Scientific and Technical Information of China (English)

    张小川; 陆博福


    Super-long coal leveling bar has been manufactured successfully by adopting split-body processing and fabrication weld moulding technique.The product quality was sufficient for technical requirement and the processing mode was economical and practical.%采用分体加工、组装焊接成型技术成功制造了超长平煤杆。产品质量符合技术要求,加工方式经济实用。

  15. Wetting and spreading behavior of molten brazing filler metallic alloys on metallic substrate (United States)

    Kogi, Satoshi; Kajiura, Tetsurou; Hanada, Yukiakira; Miyazawa, Yasuyuki


    Wetting and spreading of molten brazing filler material are important factors that influence the brazing ability of a joint to be brazed. Several investigations into the wetting ability of a brazing filler alloy and its surface tension in molten state, in addition to effects of brazing time and temperature on the contact angle, have been carried out. In general, dissimilar-metals brazing technology and high-performance brazed joint are necessities for the manufacturing field in the near future. Therefore, to address this requirement, more such studies on wetting and spreading of filler material are required for a deeper understanding. Generally, surface roughness and surface conditions affect spreading of molten brazing filler material during brazing. Wetting by and interfacial reactions of the molten brazing filler material with the metallic substrate, especially, affect strongly the spreading of the filler material. In this study, the effects of surface roughness and surface conditions on the spreading of molten brazing filler metallic alloys were investigated. Ag-(40-x)Cu-xIn and Ag- (40-x)Cu-xSn (x=5, 10, 15, 20, 25) alloys were used as brazing filler materials. A mild-steel square plate (S45C (JIS); side: 30 mm; thickness: 3mm) was employed as the substrate. A few surfaces with varying roughness were prepared using emery paper. Brazing filler material and metallic base plate were first washed with acetone, and then a flux was applied to them. The filler, 50 mg, was placed on the center of the metallic base with the flux. A spreading test was performed under Ar gas using an electrically heated furnace, after which, the original spreading area, defined as the sessile drop area, and the apparent spreading area, produced by the capillary grooves, were both evaluated. It was observed that the spreading area decreased with increasing In and Sn content.

  16. Microstructure and Mechanical Properties of AlN/Cu Brazed Joints (United States)

    Su, Cherng-Yuh; Pan, C. T.; Lo, Min-Sheng


    In this study, the AlN/Cu bonding was explored using the brazing technique. During AlN/Cu brazing, the temperature was set at 800, 850, and 900 °C for 10, 20, 30, and 60 min, respectively. We studied the bonding mechanism, microstructure formation, and the mechanical characteristics of the bond. The reaction layer developed at the interface of AlN/Cu is observed to be TiN. The activation energy of TiN is about 149.91 kJ/mol. The reaction layer thickness is linearly dependent on the temperature and duration at 800 and 850 °C for 60 min and 900 °C for 30 min. However, the growth of the reactive layers decreases gradually at 900 °C when the duration changed from 30 to 60 min. The strength of the specimens with thickness ranging between 1 and 1.5 μm is 40-51 MPa.

  17. Design, fabrication, and performance of brazed, graphite electrode, multistage depressed collectors with 500-W, continuous wave, 4.8- to 9.6-GHz traveling-wave tubes (United States)

    Ramins, Peter; Ebihara, Ben


    A small, isotropic graphite electrode, multistage depressed collector (MDC) was designed, fabricated, and evaluated in conjunction with a 500-W, continuous wave (CW), 4.8- to 9.6-GHz traveling-wave tube (TWT). The carbon electrode surfaces were used to improve the TWT overall efficiency by minimizing the secondary electron emission losses in the MDC. The design and fabrication of the brazed graphite MDC assembly are described. The brazing technique, which used copper braze filler metal, is compatible with both vacuum and the more commonly available hydrogen atmosphere brazing furnaces. The TWT and graphite electrode MCC bakeout, processing, and outgassing characteristics were evaluated and found to be comparable to TWT's equipped with copper electrode MDC's. The TWT and MDC performance was optimized for broadband CW operation at saturation. The average radiofrequency (RF), overall, and MDC efficiencies were 14.9, 46.4, and 83.6 percent, respectively, across the octave operating band. A 1500-hr CW test, conducted without the use of an appendage ion pump, showed no gas buildup and excellent stability of the electrode surfaces.

  18. Elemental composition of brazing alloys in metallic orthodontic brackets. (United States)

    Zinelis, Spiros; Annousaki, Olga; Eliades, Theodore; Makou, Margarita


    The aim of this study was to assess the elemental composition of the brazing alloy of representative orthodontic brackets. The brackets examined were Gemini (3M, Unitec, Monrovia, Calif), MicroLoc (GAC, Bohemia, NY), OptiMESHxrt (Ormco, Glendora, Calif), and Ultratrim (Dentarum, Ispringen, Germany). Four metallic brackets for each brand were embedded in epoxy resin and after metallographic grinding and polishing were cleaned in a water ultrasonic bath. Scanning electron microscopy and energy-dispersive x-ray microanalysis (EDS) were used to assess the quantitative composition of the brazing alloy. Four EDS spectra were collected for each brazing alloy, and the mean value and standard deviation for the concentration of each element were calculated. The elemental composition of the brazing alloys was determined as follows (percent weight): Gemini: Ni = 83.98 +/- 1.02, Si = 6.46 +/- 0.37, Fe = 5.90 +/- 0.93, Cr = 3.52 +/- 0.34; MicroLoc: Ag = 42.82 +/- 0.18, Au = 32.14 +/- 0.65, Cu = 24.53 +/- 0.26, Mg = 1.12 +/- 0.33; OptiMESHxrt: Au = 67.79 +/- 0.97, Fe = 15.69 +/- 0.29, Ni = 13.01 +/- 0.93, Cr = 4.01 +/- 0.35; Ultratrim: Ag = 87.97 +/- 0.33, Cu = 10.51 +/- 0.45, Mg = 1.29 +/- 0.63, Zn = 1.13 +/- 0.24. The findings of this study showed that different brazing materials were used for the different brands, and thus different performances are expected during intraoral exposure; potential effects on the biological properties also are discussed.


    Directory of Open Access Journals (Sweden)

    Sathiya Paulraj


    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.

  20. Laser powder technology for cladding and welding (United States)

    Arnold, J.; Volz, R.


    Laser powder technology offers several advantages compared to conventional cladding and welding techniques and is attracting increasing industrial interest. The laser materials processing group of the German Aerospace Center at Stuttgart, Germany, is currently developing these new methods for application in industrial process engineering. Key areas of the work include the design and implementation of a modular working head that can be universally used for laser welding and surface treatment, the development of powder nozzles for cladding and welding, and the construction of new systems for special applications (e.g., for inner cladding). Some of these developments are described, as well as some important examples that highlight the potential of welding and surface treatment using laser powder techniques.

  1. Microstructure of the Al2O3/Al2O3 Joint Brazed with Cu-Zn-Ti Filler Metal

    Institute of Scientific and Technical Information of China (English)

    Hongyuan FANG; Jianguo YANG; Xiuyu YU


    Microstructure and interface reactions of Al2O3 joints brazed by Cu-Zn-Ti alloy were studied by using SEM, EDS and XRD. The effects of brazing temperature and Ti content on interfacial reactions and microstructure were investigated, and the action of adding Zn into brazing alloy was also studied. TiO, Ti3Al and CuTi were formed at the interface of ceramics and the filler metal, while CuTi, Cu3Ti and α-Cu were found in the brazing. The thickness of the reaction layer increased with increasing of brazing temperature, under the same brazing process, the thickness increased with the Ti content.

  2. 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)


    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.

  3. Identification of the Quality Spot Welding used Non Destructive Test-Ultrasonic Testing: (Effect of Welding Time) (United States)

    Sifa, A.; Endramawan, T.; Badruzzaman


    Resistance Spot Welding (RSW) is frequently used as one way of welding is used in the manufacturing process, especially in the automotive industry [4][5][6][7]. Several parameters influence the process of welding points. To determine the quality of a welding job needs to be tested, either by damaging or testing without damage, in this study conducted experimental testing the quality of welding or identify quality of the nugget by using Non-Destructive Test (NDT) –Ultrasonic Testing (UT), in which the identification of the quality of the welding is done with parameter thickness of worksheet after welding using NDT-UT with use same material worksheet and have more thickness of worksheet, the thickness of the worksheet single plate 1mm, with the capability of propagation Ultrasonic Testing (UT) standard limited> 3 mm [1], welding process parameters such as the time difference between 1-10s and the welding current of 8 KV, visually Heat Affected Zone ( HAZ ) have different results due to the length of time of welding. UT uses a probe that is used with a frequency of 4 MHz, diameter 10 mm, range 100 and the couplant used is oil. Identification techniques using drop 6dB, with sound velocity 2267 m / s of Fe, with the result that the effect of the Welding time affect the size of the HAZ, identification with the lowest time 1s show results capable identified joined through NDT - UT.

  4. Interface structure and mechanical property of the brazed joint of graphite and copper

    Institute of Scientific and Technical Information of China (English)

    XIE Fengchun; ZHANG Lixia; FENG Jicai; HE Peng


    A kind of self-made AgCuTiSn braze alloy powder was used to join graphite and copper. The whole brazing process was performed under vacuum circumstances at different temperatures (1033-1193 K) for several holding time (300-1800 s). According to scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and electron probe X-ray microanalysis (EPMA) results, the reaction products of the interface are TiC, Ti3Sn, Cu(s. s), Ag(s. s) and Cu-Sn compound. As the brazing parameters increase, the quantity of Ag(s. s) in the braze alloy and C fibers on graphite/AgCuTiSn interface reduce, while that of Cu (s. s) in the braze alloy improves. When the brazing temperature is 1093 K and holding time is 900 s, the joint can obtain the maximum room temperature shear strength 24 MPa.

  5. Dissimilar joint characteristics of SiC and WC-Co alloy by laser brazing (United States)

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


    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. Characterization of Brazed Joints of C-C Composite to Cu-clad-Molybdenum (United States)

    Singh, M.; Asthana, R.


    Carbon-carbon composites with either pitch+CVI matrix or resin-derived matrix were joined to copper-clad molybdenum using two active 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 de-lamination in resin-derived C-C composite due to its low inter-laminar shear strength. Extensive braze penetration of the inter-fiber channels in the pitch+CVI C-C composites was observed. The relatively low brazing temperatures (Cu-clad-Mo/braze interface and higher hardness in Ticusil (approx.85-250 HK) than in Cusil-ABA (approx.50-150 HK). These C-C/Cu-clad-Mo joints with relatively low thermal resistance may be promising for thermal management applications.

  7. The Kinetics of Phase Transformation in Welds

    Energy Technology Data Exchange (ETDEWEB)

    Elmer, J W; Wong, J; Palmer, T


    The fundamentals of welding-induced phase transformations in metals and alloys are being investigated using a combination of advanced synchrotron based experimental methods and modem computational science tools. In-situ experimental methods have been developed using a spatially resolved x-ray probe to enable direct observations of phase transformations under the real non- isothermal conditions experienced during welding. These experimental techniques represent a major step forward in the understanding of phase transformations that occur during welding, and are now being used to aid in the development of models to predict microstructural evolution under the severe temperature gradients, high peak temperatures and rapid thermal fluctuations characteristic of welds. Titanium alloys, stainless steels and plain carbon steels are currently under investigation, and the phase transformation data being obtained here cannot be predicted or measured using conventional metallurgical approaches. Two principal synchrotron-based techniques have been developed and refined for in-situ investigations of phase transformation dynamics in the heat-affected zone (HAZ) and fusion zone (FZ) of welds: Spatially Resolved X-Ray Diffraction (SRXRD) and Time Resolved X-Ray Diffraction (TRXRD). Both techniques provide real-time observations of phases that exist during welding, and both have been developed at the Stanford Synchrotron Radiation Laboratory (SSRL) using a high flux wiggler beam line. The SRXRD technique enables direct observations of the phases existing in the HAZ of quasi-stationary moving arc welds, and is used to map the HAZ phases by sequentially jogging the weld with respect to the x-ray beam while taking x-ray diffraction (XRD) patterns at each new location. These spatially resolved XRD patterns are collected in linear traverses perpendicular to the direction of weld travel. The XRD data contained in multiple traverses is later compiled to produce an areal map of the phases

  8. Weld repair of helium degraded reactor vessel material

    Energy Technology Data Exchange (ETDEWEB)

    Kanne, W.R. Jr.; Lohmeier, D.A.; Louthan, M.R. Jr.; Rankin, D.T.; Franco-Ferreira, E.A. (Westinghouse Savannah River Co., Aiken, SC (United States)); Bruck, G.J.; Madeyski, A.; Shogan, R.P.; Lessmann, G.G. (Westinghouse Electric Corp., Pittsburgh, PA (United States). Science and Technology Center)


    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.

  9. Weld repair of helium degraded reactor vessel material

    Energy Technology Data Exchange (ETDEWEB)

    Kanne, W.R. Jr.; Lohmeier, D.A.; Louthan, M.R. Jr.; Rankin, D.T.; Franco-Ferreira, E.A. [Westinghouse Savannah River Co., Aiken, SC (United States); Bruck, G.J.; Madeyski, A.; Shogan, R.P.; Lessmann, G.G. [Westinghouse Electric Corp., Pittsburgh, PA (United States). Science and Technology Center


    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. 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...

  11. Vacuum Brazing of TiAl Based Alloy with 40Cr Steel

    Institute of Scientific and Technical Information of China (English)

    周昀; 薛小怀; 吴鲁海; 楼松年


    The vacuum brazing of TiAl based alloy with 40Cr steel was investigated using Ag-Cu-Ti filler metal.The experimental results show that the Ag, Cu, Ti atoms in the filler metal and the base metal inter-diffuse toward each other during brazing and react at the interface to form an inter-metallic AlCu2Ti compound which joins two parts to produce a brazing joint with higher strength.

  12. 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


    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.

  13. Research on Phased Array Automatically Ultrasonic Testing Technique of Tube to Tube-sheet Welds in Heat Exchanger%换热器管板角焊缝相控阵自动超声检测技术研究

    Institute of Scientific and Technical Information of China (English)

    郭伟灿; 钱盛杰; 凌张伟


    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. 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: [ININ, Carretera Mexico-Toluca s/n, 52750 Ocoyoacac, Estado de Mexico (Mexico)


    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)

  15. Coil Welding Aid (United States)

    Wiesenbach, W. T.; Clark, M. C.


    Positioner holds coil inside cylinder during tack welding. Welding aid spaces turns of coil inside cylinder and applies contact pressure while coil is tack-welded to cylinder. Device facilitates fabrication of heat exchangers and other structures by eliminating hand-positioning and clamping of individual coil turns.

  16. Instructional Guidelines. Welding. (United States)

    Fordyce, H. L.; Doshier, Dale

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

  17. Variable polarity arc welding (United States)

    Bayless, E. O., Jr.


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

  18. 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


    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.

  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


    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. Infrared Brazing Ti50Ni50 and Invar Using Ag-Based Filler Foils (United States)

    Shiue, R. K.; Chang, Y. H.; Wu, S. K.


    Infrared brazing Ti50Ni50 and Invar using BAg-8 and Cusil-ABA foils was investigated. The Ag-Cu eutectic matrix dominates both brazed joints. The maximum shear strengths of the brazed joints using BAg-8 and Cusil-ABA fillers are 158 and 249 MPa. Failure of interfacial Fe2Ti/Ni3Ti reaction layers is responsible for the BAg-8 joint. In contrast, the Cusil-ABA brazed joint is fractured along the interfacial Fe2Ti intermetallic compound. Both fractographs are characterized with cleavage dominated fracture.

  1. High Power Laser Welding. [of stainless steel and titanium alloy structures (United States)

    Banas, C. M.


    A review of recent developments in high power, carbon dixoide laser welding is presented. Deep penetration welding in stainless steel to 0.5-in. thick, high speed welding in thin gage rimmed steel and gas shielded welding in Ti-6Al-4V alloy are described. The effects of laser power, power density, focusing optics, gas-shielding techniques, material properties and weld speed on weld quality and penetration are discussed. It is shown that laser welding performance in thin materials is comparable to that of electron beams. It is further shown that high quality welds, as evidenced by NDT, mechanical and metal-lographic tests, can be achieved. The potential of the laser for industrial welding applications is indicated.

  2. Research on Welding Test of Grey Cast Iron and Low-Carbon Steel

    Institute of Scientific and Technical Information of China (English)


    Grey cast iron's welding itself is a complex proble m.So proper welding materials must be selected,complex welding techniques such as preheating before weldingslow cooling after welding etc,should be taken. However the carbon component in low-carbon steel is comparatively low,the carbo n of welded joint will diffuse to the low-carbon steel when it is welded with gr ey cast iron,which will cause the component of carbon greatly increased at the low-carbon steel side in HAZ,high carbon martensite and cracks ...

  3. 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


    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.

  4. Analysis of Laser-Brazed Diamond Particle Microstructures

    Directory of Open Access Journals (Sweden)

    Zhibo YANG


    Full Text Available Brazing diamond particles to a steel substrate using Ni-based filler alloy was carried out via laser in an argon atmosphere. The brazed diamond particles were detected by scanning electron microscope (SEM, X-ray diffraction (XRD, and energy dispersive X-ray spectroscopy (EDS. The formation mechanism of carbide layers was discussed. All the results indicated that a high-strength bond between the diamond particles and the steel substrate was successfully realized. The chromium in the Ni-based alloy segregated preferentially to the surfaces of the diamonds to form a chromium-rich reaction product, and the bond between the alloy and the steel substrate was established through a cross-diffusion of iron and Ni-based alloy.DOI:

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

    CERN Document Server

    Loos, Robert


    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.

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

    Directory of Open Access Journals (Sweden)

    Pushp Kumar Baghel


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

  7. Research of Brazing Filler Metals for 6061 Aluminum Alloy Brazing%6061铝合金钎焊用钎料的研究

    Institute of Scientific and Technical Information of China (English)

    刘正林; 杨凯珍; 王凯; 刘凤美


    研究了6061铝合金钎焊用中温钎料Al-Si-Cu-Ni钎料的熔化特性、钎焊强度、钎料和接头抗腐蚀性能.结果表明,Al-Si-Cu-Ni钎料熔化温度与Al-Si-Cu钎料HL401接近,钎焊强度、钎料和接头抗腐蚀性能均优于HL401;Al-10Cu- 10Si-2Ni钎料熔化温度低,抗拉强度和接头抗腐蚀性能高,适用于6061铝合金的钎焊.%Melting characteristics, brazing strength, corrosion resistance of filler metals and joints of the Al-Si-Cu-Ni brazing filler metals for 6061 alloy brazing were studied. The results show that, the melting temperature of Al-Si-Cu-Ni brazing filler metals are close to the Al-Si-Cu solder HL401and the brazing strength, the corrosion resistance of filler metals and joints are better than HL401; Al-10Cu-10Si-2Ni filler matel with low melting temperature, high brazing strength and better corrosion resistance of joint is suitable for 6061 aluminum alloy brazing.

  8. Remote Welding, NDE and Repair of DOE Standardized Canisters

    Energy Technology Data Exchange (ETDEWEB)

    Eric Larsen; Art Watkins; Timothy R. McJunkin; Dave Pace; Rodney Bitsoi


    The U.S. Department of Energy (DOE) created the National Spent Nuclear Fuel Program (NSNFP) to manage DOE’s spent nuclear fuel (SNF). One of the NSNFP’s tasks is to prepare spent nuclear fuel for storage, transportation, and disposal at the national repository. As part of this effort, the NSNFP developed a standardized canister for interim storage and transportation of SNF. These canisters will be built and sealed to American Society of Mechanical Engineers (ASME) Section III, Division 3 requirements. Packaging SNF usually is a three-step process: canister loading, closure welding, and closure weld verification. After loading SNF into the canisters, the canisters must be seal welded and the welds verified using a combination of visual, surface eddy current, and ultrasonic inspection or examination techniques. If unacceptable defects in the weld are detected, the defective sections of weld must be removed, re-welded, and re-inspected. Due to the high contamination and/or radiation fields involved with this process, all of these functions must be performed remotely in a hot cell. The prototype apparatus to perform these functions is a floor-mounted carousel that encircles the loaded canister; three stations perform the functions of welding, inspecting, and repairing the seal welds. A welding operator monitors and controls these functions remotely via a workstation located outside the hot cell. The discussion describes the hardware and software that have been developed and the results of testing that has been done to date.

  9. Laser Brazing with Beam Scanning: Experimental and Simulative Analysis (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.

  10. Optically controlled welding system (United States)

    Gordon, Stephen S. (Inventor)


    An optically controlled welding system (10) wherein a welding torch (12) having through-the-torch viewing capabilities is provided with an optical beam splitter (56) to create a transmitted view and a reflective view of a welding operation. These views are converted to digital signals which are then processed and utilized by a computerized robotic welder (15) to make the welding torch responsive thereto. Other features includes an actively cooled electrode holder (26) which minimizes a blocked portion of the view by virtue of being constructed of a single spoke or arm (28) and a weld pool contour detector (14) comprising a laser beam directed onto the weld pool with the position of specular radiation reflected therefrom being characteristic of a penetrated or unpenetrated condition of the weld pool.

  11. Cold metal transfer spot plug welding of AA6061-T6-to-galvanized steel for automotive applications

    Energy Technology Data Exchange (ETDEWEB)

    Cao, R., E-mail:; Huang, Q.; Chen, J.H., E-mail:; Wang, Pei-Chung


    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.

  12. A study on brazing of Glidcop® to OFE Cu for application in Photon Absorbers of Indus-2 (United States)

    Yadav, D. P.; Kaul, R.; Ram Sankar, P.; Kak, A.; Ganesh, P.; Shiroman, R.; Singh, R.; Singh, A. P.; Tiwari, P.; Abhinandan, L.; Kukreja, L. M.; Shukla, S. K.


    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.

  13. Numerical aspects for efficient welding computational mechanics

    Directory of Open Access Journals (Sweden)

    Aburuga Tarek Kh.S.


    Full Text Available The effect of the residual stresses and strains is one of the most important parameter in the structure integrity assessment. A finite element model is constructed in order to simulate the multi passes mismatched submerged arc welding SAW which used in the welded tensile test specimen. Sequentially coupled thermal mechanical analysis is done by using ABAQUS software for calculating the residual stresses and distortion due to welding. In this work, three main issues were studied in order to reduce the time consuming during welding simulation which is the major problem in the computational welding mechanics (CWM. The first issue is dimensionality of the problem. Both two- and three-dimensional models are constructed for the same analysis type, shell element for two dimension simulation shows good performance comparing with brick element. The conventional method to calculate residual stress is by using implicit scheme that because of the welding and cooling time is relatively high. In this work, the author shows that it could use the explicit scheme with the mass scaling technique, and time consuming during the analysis will be reduced very efficiently. By using this new technique, it will be possible to simulate relatively large three dimensional structures.

  14. An Assessment of Molten Metal Detachment Hazards During Electron Beam Welding in the Space Shuttle Bay at LEO for the International Space Welding Experiment (United States)

    Fragomeni, James M.


    In 1997, the United States [NASA] and the Paton Electric Welding Institute are scheduled to cooperate in a flight demonstration on the U.S. Space Shuttle to demonstrate the feasibility of welding in space for a possible repair option for the International Space Station Alpha. This endeavor, known as the International Space Welding Experiment (ISWE), will involve astronauts performing various welding exercises such as brazing, cutting, welding, and coating using an electron beam space welding system that was developed by the E.O. Paton Electric Welding Institute (PWI), Kiev Ukraine. This electron beam welding system known as the "Universal Weld System" consists of hand tools capable of brazing, cutting, autogeneous welding, and coating using an 8 kV (8000 volts) electron beam. The electron beam hand tools have also been developed by the Paton Welding Institute with greater capabilities than the original hand tool, including filler wire feeding, to be used with the Universal Weld System on the U.S. Space Shuttle Bay as part of ISWE. The hand tool(s) known as the Ukrainian Universal Hand [Electron Beam Welding] Tool (UHT) will be utilized for the ISWE Space Shuttle flight welding exercises to perform welding on various metal alloy samples. A total of 61 metal alloy samples, which include 304 stainless steel, Ti-6AI-4V, 2219 aluminum, and 5456 aluminum alloys, have been provided by NASA for the ISWE electron beam welding exercises using the UHT. These samples were chosen to replicate both the U.S. and Russian module materials. The ISWE requires extravehicular activity (EVA) of two astronauts to perform the space shuttle electron beam welding operations of the 61 alloy samples. This study was undertaken to determine if a hazard could exist with ISWE during the electron beam welding exercises in the Space Shuttle Bay using the Ukrainian Universal Weld System with the UHT. The safety issue has been raised with regard to molten metal detachments as a result of several

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

    Energy Technology Data Exchange (ETDEWEB)

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


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

  16. Influence of PWHT on Toughness of High Chromium and Nickel Containing Martensitic Stainless Steel Weld Metals (United States)

    Divya, M.; Das, Chitta Ranjan; Mahadevan, S.; Albert, S. K.; Pandian, R.; Kar, Sujoy Kumar; Bhaduri, A. K.; Jayakumar, T.


    Commonly used 12.5Cr-5Ni consumable specified for welding of martensitic stainless steels is compared with newly designed 14.5Cr-5Ni consumable in terms of their suitability for repair welding of 410 and 414 stainless steels by gas tungsten arc welding process. Changes in microstructure and austenite evolution were investigated using optical, scanning electron microscopy, X-ray diffraction techniques and Thermo-Calc studies. Microstructure of as-welded 12.5Cr-5Ni weld metal revealed only lath martensite, whereas as-welded 14.5Cr-5Ni weld metal revealed delta-ferrite, retained austenite, and lath martensite. Toughness value of as-welded 12.5Cr-5Ni weld metal is found to be significantly higher (216 J) than that of the 14.5Cr-5Ni weld metal (15 J). The welds were subjected to different PWHTs: one at 923 K (650 °C) for 1, 2, 4 hours (single-stage PWHT) and another one at 923 K (650 °C)/4 h followed by 873 K (600 °C)/2 h or 873 K (600 °C)/4 h (two-stage heat treatment). Hardness and impact toughness of the weld metals were measured for these weld metals and correlated with the microstructure. The study demonstrates the importance of avoiding formation of delta-ferrite in the weld metal.

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

    Energy Technology Data Exchange (ETDEWEB)

    Dagel, Daryl; GROSSETETE, GRANT; Maccallum, Danny O.


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

  18. A Neural Network Approach for GMA Butt Joint Welding

    DEFF Research Database (Denmark)

    Christensen, Kim Hardam; Sørensen, Torben


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

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

    Energy Technology Data Exchange (ETDEWEB)

    Brummer, G. [High Energy Weapons (United States); Dauwel, W.; Wesseling, U. [Framatome ANP GmbH-NBTT, Erlangen (Germany); Ilg, U. [EnBW, Milano (Italy); Lauer, P.; Widera, M. [E.ON Kernkraft (Germany); Wachter, O. [RWE Power (Germany)


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

  20. Monitoring of martensite formation during welding by means of acoustic emission

    Energy Technology Data Exchange (ETDEWEB)

    Bohemen, S.M.C. van; Hermans, M.J.M.; Ouden, G. den [Netherlands Institute for Metals Research, Delft University of Technology, Delft (Netherlands)


    The martensitic transformation during gas tungsten arc (GTA) welding of steel 42CrMo4 has been studied using the acoustic emission (AE) monitoring technique. Welds were produced under static conditions (spot welding) and under stationary conditions (travelling arc welding). After spot welding, the root mean square (RMS) value of the continuous acoustic emission was measured, revealing a peak that reflects the evolution of martensite formation during cooling of the spot weld. The RMS value was also measured during travelling arc welding at different heat inputs and corrected for the noise of the welding process to obtain the RMS value due to martensite formation. After welding, optical metallography was carried out to quantify the amount of martensite formed during cooling of the weld. An analysis of the results shows that the squared RMS value is proportional to the volume rate of martensite formation during welding, which is consistent with theory and in good agreement with the results obtained in the case of spot welding. The obtained results suggest that AE can be applied as a real time monitoring technique for the detection of martensite formation during steel welding. (author)

  1. Influence of the welding parameters on the heat affected zone for aluminium welding

    Directory of Open Access Journals (Sweden)

    Meseguer-Valdenebro José L.


    Full Text Available This work analyzes the Heat Affected Zone in an aluminum alloy welded assembly using the Metal Inert Gas welding technique. Making use of numerical simulations of the involved thermal processes, the aluminum alloy cooling curve is calculated and the extension of the Heat Affected Zone is evaluated. The connection between this last parameter, the cooling rate, and the maximum obtained temperature is assessed. Additionally, the response surface method is exploited to fit the dependence of the Heat Affected Zone with the welding parameters and to optimize these parameters in order to minimize that region.

  2. A review of using computational fluid dynamic in simulating of friction stir welding and parametric studies


    Hamza, Esam


    Friction Stir Welding (FSW) is still gradually evolving where it is newer than most thermomechanical processes and due to its ability to avoid many of the common defects in other welding techniques it has become largely used, particularly for those materials that are soft.[1]\\ud Since the invention of friction stir welding by The Welding Institute (TWI), Cambridge, UK, there have been many attempts to comprehend the physical phenomena that take place during this process. These phenomena can b...

  3. Microstructural Investigation and Evaluation of Mechanical Properties in Friction Stir Welded Joints (United States)


    Properties in Friction Stir Welded Joints BRIAN JUSTUSSON MENTORS: DR. CONSTANTINE FOUNTZOULAS AND DR. CHIAN-FONG YEN U.S. ARMY RESEARCH LABORATORY...2011 4. TITLE AND SUBTITLE Microstructural Investigation And Evaluation Of Mechanical Properties In Friction Stir Welded Joints 5a. CONTRACT NUMBER...of the weldment can be costly and needs to be addressed. Friction Stir Welding (FSW) is a solid-state welding technique, which involves local softening

  4. Combined Laser Beam Welding and Brazing Process for Aluminium Titanium Hybrid Structures (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.

  5. Interfacial metallurgy study of brazed joints between tungsten and fusion related materials for divertor design (United States)

    Zhang, Yuxuan; Galloway, Alexander; Wood, James; Robbie, Mikael Brian Olsson; Easton, David; Zhu, Wenzhong


    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.

  6. VPPA weld model evaluation (United States)

    McCutcheon, Kimble D.; Gordon, Stephen S.; Thompson, Paul A.


    NASA uses the Variable Polarity Plasma Arc Welding (VPPAW) process extensively for fabrication of Space Shuttle External Tanks. This welding process has been in use at NASA since the late 1970's but the physics of the process have never been satisfactorily modeled and understood. In an attempt to advance the level of understanding of VPPAW, Dr. Arthur C. Nunes, Jr., (NASA) has developed a mathematical model of the process. The work described in this report evaluated and used two versions (level-0 and level-1) of Dr. Nunes' model, and a model derived by the University of Alabama at Huntsville (UAH) from Dr. Nunes' level-1 model. Two series of VPPAW experiments were done, using over 400 different combinations of welding parameters. Observations were made of VPPAW process behavior as a function of specific welding parameter changes. Data from these weld experiments was used to evaluate and suggest improvements to Dr. Nunes' model. Experimental data and correlations with the model were used to develop a multi-variable control algorithm for use with a future VPPAW controller. This algorithm is designed to control weld widths (both on the crown and root of the weld) based upon the weld parameters, base metal properties, and real-time observation of the crown width. The algorithm exhibited accuracy comparable to that of the weld width measurements for both aluminum and mild steel welds.

  7. Development of automated welding process for field fabrication of thick walled pressure vessels. Fourth quarter technical progress report for period ending September 28, 1980

    Energy Technology Data Exchange (ETDEWEB)


    Progress is reported in research aimed at optimizing an automated welding process for the field fabrication of thick-walled pressure vessels and for evaluating the welded joints. Information is included on the welding equipment, mechanical control of the process, joint design, filler wire optimization, in-process nondestructive testing of welds, and repair techniques. (LCL)

  8. 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: [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)


    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.

  9. 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


    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.

  10. 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:; 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)


    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.

  11. Reduction of liquid metal embrittlement in copper-brazed stainless steel joints (United States)

    Uhlig, T.; Fedorov, V.; Elßner, M.; Wagner, G.; Weis, S.


    Due to its very good formability and the low raw material cost, pure copper in form of foils is commonly used to braze plate heat exchangers made of stainless steel. The difference in the electrochemical potentials of brazing filler and base material leads to corrosion effects in contact with electrolytes. This may lead to leakages, which decrease the reliability of the heat exchanger during service in potable water. The dissolution of the emerging corrosion products of brazing filler and base material induces the migration of heavy metal ions, such as Cu2+ and Ni2+, into the potable water. The so-called liquid metal embrittlement, which takes place during the brazing process, may intensify the corrosion. The brazing filler infiltrates the stainless steel along the grain boundaries and causes an embrittlement. This paper deals with the determination of the grain boundary erosion dependent on the degree of deformation and heat treatment of the stainless steel AISI 316L.

  12. Comparative Investigation on Brazing Behavior, Compressive Strength, and Wear Properties of Multicrystalline CBN Abrasive Grains

    Directory of Open Access Journals (Sweden)

    Wen-Feng Ding


    Full Text Available In order to fabricate the abrasive wheels with good grain self-sharpening capacity, two types of multicrystalline CBN grains, that is, polycrystalline CBN (PCBN and binderless CBN (BCBN, were brazed using Cu-Sn-Ti alloy, respectively. Comparative investigation on the brazing interface, compressive strength, and wear properties of the different grains was carried out. Results obtained show that the PCBN grains have more intricate reaction, more complicated resultants, and thicker reaction layer than the BCBN counterparts under the identical brazing conditions. Though the average compressive strength of the PCBN grains is similar to that of BCBN ones, stronger self-sharpening action by virtue of the microfracture behavior takes place with BCBN grains during grinding. As a consequence, compared to the brazed PCBN wheels and the conventional monocrystalline CBN (MCBN ones, longer service life is obtained for the brazed BCBN wheels.

  13. 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


    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 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.

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

    Directory of Open Access Journals (Sweden)

    Ming Gao


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

  15. Dual wire welding torch and method (United States)

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


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

  16. Self-calibration technique for structured light vision guided welding robot system%结构光视觉引导的焊接机器人系统自标定技术

    Institute of Scientific and Technical Information of China (English)

    郭新年; 白瑞林; 王秀平; 刘子腾


    To achieve the structured light vision guided welding robot system calibration, and solve the problem of complex, and difficult to make target in the existing calibration methods, a new self-calibration technique based on active vision is proposed. This self-calibration technique calibrates the camera inner parameter, rotating section of hand-eye matrix by controlling the robot 5 pure translational motions. And it calibrates the translation section of hand-eye matrix and the equa-tion of the light plane by controlling the robot 2 motions with revolving with three feature points in the scene without a specific target. The actual test results in the structured light vision guided welding robot system based on Denso robot show that the calibration approach is stable, and can reach the precision of ±0.93 mm. This self-calibration method to the structured light vision guided welding robot system with easy feature selection is simple, and has significance to the actual use in the field of industry.%为实现结构光视觉引导的焊接机器人系统的标定,解决现有标定方法复杂,标定靶标制作要求高等缺点,提出一种基于主动视觉的自标定方法。该标定方法对场景中3个特征点取像,通过精确控制焊接机器人进行5次平移运动,标定摄像机内参数和手眼矩阵旋转部分;通过进行2次带旋转运动,结合激光条在特征点平面的参数方程,标定手眼矩阵平移部分和结构光平面在摄像机坐标系下的平面方程;并针对不同焊枪长度进行修正。在以Denso机器人为主体构建的结构光视觉引导的焊接机器人系统上的测试结果稳定,定位精度可达到±0.93 mm。该标定方法简单,特征选取容易,对焊接机器人系统在实际工业现场的使用有重要意义。

  17. 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


    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.

  18. Ultrasonic Stir Welding (United States)

    Nabors, Sammy


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

  19. Testing of welded seams in the light of new requirements. Rules, new joining techniques, new test methods, automation, code cases; Schweissnahtpruefung im Licht neuer Anforderungen. Regelwerke, neue Fuegetechniken, neue Prueftechniken, Automatisierung, Code Cases

    Energy Technology Data Exchange (ETDEWEB)



    This proceedings CD contains 8 contributions on the following subjects: 1. Ultrasonic testing of welds using TOFD (A. Hecht); 2. Automated Ultrasonic Pipe Weld Inspection - Inspection of Welded Pipes in Accordance with New and Strict International Specifications (W.A.K. Deutsch); 3. Detection and analysis of longitudinal defects in welds of pipelines (K. Reber); 4. Ultrasonic inline inspection of pipelines for circumferential cracks (H. Willems); 6. Ultrasonic testing of welds at temperatures up to 200 C (A. Erhard); 7. Defect detection and defect size measurement in welds using ultrasonic phased arrays (W. Rathgeb); 8. Dry ultrasonic testing of laser-welded butt welds using guided SH waves illustrated by the example of tailored blanks (H.-J. Salzburger). Four papers are available as separate records in the ENERGY database. [German] Diese Berichtsband-CD enthaelt 8 Beitraege mit folgenden Themen: 1. Ultraschallpruefung an Schweissnaehten mittels TOFD (A. Hecht); 2. Automated Ultrasonic Pipe Weld Inspection - Inspection of Welded Pipes in Accordance with New and Strict International Specifications (W.A.K. Deutsch); 3. Detektion und Bewertung von Laengsfehlern an Schweissnaehten von Pipelines (K. Reber); 4. Inline-Pruefung von Pipelines auf Umfangrisse mittels Ultraschall (H. Willems); 6. Ultraschallschweissnahtpruefung bei Temperaturen bis 200 C (A. Erhard); 7. Fehlerauffindung und Fehlergroessenbestimmung mit der Gruppenstrahlertechnik bei der Schweissnahtpruefung (W. Rathgeb); 8. Trockene Ultraschallpruefung lasergeschweisster Stumpfschweissnaehte mittels gefuehrter SH-Wellen am Beispiel der Tailored Blanks (H.-J. Salzburger). Vier der Beitraege wurden separat fuer die ENERGY Datenbank aufgenommen.

  20. Residual Stress and Bonding Strength in the ElectricalSialon Ceramics Joint Made by Using the Brazing Metal Layer


    Kimura, Mitsuhiko; Asari, Koichi; GOTO, Shoji; Aso, Setsuo


    Electrical Sialons which have some TiN contents were joined with Ag-Cu-Ti active brazing metal layer having a thickness from 30μm to 400μm at a temperature from 1113 K to 1213 K in a vacuum. Residual stress in the brazed joint specimens was not observed when the thickness of brazing metal layer was 30 μ m. However, the residual stress of 80 MPa was detected when the thickness of brazing metal layer increased up to 400μm. When the brazing temperature was 1113 K, four-point bending strengths of...

  1. 防错技术在汽车车架焊接过程中的应用%The Application of Error Proofing Technique in Automotive Frame Welding Process

    Institute of Scientific and Technical Information of China (English)

    张永红; 陈书强; 韩福生


    With the pursuit of zero defects, how to achieve zero defects management is crucial, and poka-yoke is the best way to achieve zero defect management. Giving priority to prevention is emphasized and the potential risks must be prevented firstly. The application of error proofing is an effective method, and it can eliminate the error from its root. Error proofing technique is widely used in automotive frame welding process. For the common errors in the process of frame welding, poka-yoke technique can eliminate the phenomenon of assembled incorrectly and omitted assembly to ensure the accuracy of products and improve the frame quality.%人们都在追求零缺陷,如何实现零缺陷管理至关重要,防错法是实现零缺陷管理的最佳途径。工作中强调预防为主的理念,先要预防可能存在的风险,防错技术的应用是预防风险的一种有效手段,它能从根源上杜绝错误的产生。防错技术在车架焊接过程中应用广泛,对于焊接过程中的常见错误,通过防错技术能消除其中的错装和漏装现象,保证产品精度,提升车架质量。

  2. Manganese Content Control in Weld Metal During MAG Welding (United States)

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


    The influence of the welding current and method of gas shielding in MAG welding on the content of manganese is considered in the paper. Results of study of the welded specimens of steels 45 when applying welding wire of different formulas and different types of gas shielding (traditional shielding and double-jet shielding) are given. It is found that in MAG welding the value of the welding current and the speed of the gas flow from the welding nozzle have a considerable impact on the chemical composition of the weld metal. The consumable electrode welding under double-jet gas shielding provides the directed gas-dynamics in the welding area and enables controlling the electrode metal transfer and the chemical composition of a weld.

  3. Characterization through nano indentation technique of mechanical properties of an aluminium alloy welded zone for hydrogen storage; Apport de la nanoindentation pour la caracterisation d'un cordon de soudure par faisceau d'electrons d'un reservoir d'hydrogene sous pression en alliage d'aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Delobelle, P.; Perreux, D.; Russo, C. [Universite de Franche-Comte, Institut FEMTO-ST, UMR 6174, Depart. LMARC, 25 - Besancon (France); Meunier, E. [CEA Valduc (DRMN/SMCM/LCSi), 21 - Is-sur-Tille (France); Decamps, B. [Laboratoire de Chimie Metallurgique des Terres Rares, UPR 209, 94 - Vitry-Thiais, (France)


    In this study we use the nano indentation technique which is a powerful tool to characterise the mechanical properties of a welded bond. The Berkovich indentation has the advantage to test small material volumes compared to the conventional tensile tests. The welded process with electrons beam of hydrogen vessels induces different regions and the aim of this study is to characterize the differences of the mechanical properties of the different zones of the weld. To identify the stress-strain curves of the tested material, F.E. inverse method has been used. After treatment, for one pass, the hardness of the melted zone is greater than those of the base material and for the two passes, the hardness is still lower than those of the base material. The interface zones present a hardness which is always higher than those of the weld. A relation of the Hall-Petch type which correlates the evolution of the hardness with the zinc concentration and the grain size has been proposed. Moreover a relation between the normalized hardness and the hydrogen concentration CH has been found. The parameters of the stress-strain curves of the four regions; base material, interface, one and two passes melted zones, have been deduced. The identified laws are used in a F.E. model of a welded sphere to model its radial deformation under internal pressure loading. (authors)

  4. Evolution of Microstructure in Brazed Joints of Austenitic-Martensitic Stainless Steel with Pure Silver Obtained with Ag-27Cu-5Sn Brazing Filler Material (United States)

    Gangadharan, S.; Sivakumar, D.; Venkateswaran, T.; Kulkarni, Kaustubh


    Brazing of an austenitic-martensitic stainless steel (AMSS) with pure silver was carried out at 1053 K, 1073 K, and 1093 K (780 °C, 800 °C, and 820 °C) with Ag-27Cu-5Sn (wt pct) as brazing filler material (BFM). Wettability of the liquid BFM over base AMSS surface was found to be poor. Application of nickel coating to the steel was observed to enhance the wettability and to enable the formation of a good bond between BFM and the steel. The mechanism responsible for enhanced metallurgical bonding of the BFM with AMSS in the presence of nickel coating was explained based on diffusional interactions and uphill diffusion of iron, chromium and nickel observed in the brazed microstructure. Good diffusion-assisted zone was observed to form on silver side at all three temperatures. Four phases were encountered within the joint including silver solid solution, copper solid solution, Cu3Sn intermetallic and Ni-Fe solid solution. The Cu3Sn intermetallic was present in small amounts in the joints brazed at 1053 K and 1073 K (780 °C and 800 °C). The joint formed at 1093 K (820 °C) exhibited the absence of Cu3Sn, fewer defects and larger diffusion-assisted zone. Hardness of base AMSS was found to reduce during brazing due to austenite reversion and post-brazing sub-zero treatment for 2.5 hours was found suitable to recover the hardness.

  5. Studies on corrosion protection of laser hybrid welded AISI 316 by laser remelting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Ambat, Rajan; Rasmussen, A.J.


    Unlike in autogenous laser welding, hybrid laser welding of stainless steel could introduce grain boundary carbides due to low cooling rates. Formation of grain boundary carbides leads to reduced corrosion properties. Studies have initially been carried out on hybrid laser welding and subsequent...... laser surface melting on microstructure and corrosion behaviour of AISI 316L welds. Welding and laser treatment parameters were varied. General corrosion behaviour of the weld and laser treated surface was characterised using a gel visualization test. The local electrochemistry of the weld and laser...... treated surface was investigated using a novel micro electrochemical technique with a tip resolution of ~1 mm. Results show that hybrid laser welding of 316L has increased corrosion susceptibility probably as a result of grain boundary carbide formation. However a suitable post laser treatment could...

  6. Comparative study of TIG and SMAW root welding passes on ductile iron cast weldability

    Directory of Open Access Journals (Sweden)

    J. Cárcel-Carrasco


    Full Text Available This work compares the weldability of ductile iron when: (I a root weld is applied with a tungsten inert gas (TIG process using an Inconel 625 source rod and filler welds are subsequently applied using coated electrodes with 97,6%Ni; and (II welds on ductile iron exclusively made using the manual shielded metal arc welding technique (SMAW. Both types of welds are performed on ductile iron specimen test plates that are subjected to preheat and post-weld annealing treatments. Samples with TIG root-welding pass shown higher hardness but slightly lower ductility and strength. Both types of welding achieved better ductile and strength properties than ones found in literature.

  7. Al2O3/SUS304 Brazing via AgCuTi-W Composite as Active Filler (United States)

    Su, Cherng-Yuh; Zhuang, Xie-Zongyang; Pan, Cheng-Tang


    Alumina ceramic (α-Al2O3) was brazed to stainless steel (SUS304) using an Ag-Cu-Ti + W composite filler and a traditional active brazing filler alloy (CuSil-ABA). Then, the effects of the presence of W particles and of the brazing parameters on the microstructures and mechanical properties of the brazed joints were investigated. The maximum tensile strength of the joints obtained using Ag-Cu-Ti + W composite filler was 13.2 MPa, which is similar to that obtained using CuSil-ABA filler (13.5 MPa). When the joint was brazed at 930 °C for 30 min, the tensile strengths decreased for both kinds of fillers, although the strength was slightly higher for the Ag-Cu-Ti + W composite filler than for the Ag-Cu-Ti filler. The interfacial microstructure results show that the Ti reacts with W to form a Ti-W-O compound in the brazing alloy. When there are more W particles in the brazing alloy, the thickness of the Ti X O Y reaction layer near the alumina ceramic decreases. Moreover, W particles added to the brazing alloy can reduce the coefficient of thermal expansion of the brazing alloy, which results in lower residual stress between the Al2O3 and SUS304 in the brazing joints and thus yields higher tensile strengths as compared to those obtained using the CuSil-ABA brazing alloy.

  8. Ultrasonic Inspection Technique and Qualification for Reactor Pressure Vessel Weld of Nuclear Power Plant%核电站反应堆压力容器焊缝的超声检测及验证

    Institute of Scientific and Technical Information of China (English)

    许远欢; 聂勇


      The ultrasonic inspection technique for reactor pressure vessel weld of nuclear power plant was described.The ultrasonic transmission characterization and the influence factors of defects detection and sizing are analyzed in detail .A serial of testing is done to verify the UT technique .The ultrasonic tech-nique can effectively detect and size the defects and has been qualified by the separate qualification cen -ter UK-IVC.The technique meets the requirement of ultrasonic inspection of in -service inspection rules for the mechanical components of PWR nuclear islands (RES-M 1997).%  通过对反应堆压力容器焊缝超声波传播特性以及超声波缺陷探测和定量影响因素的分析,并通过大量的试验测试研究,确定了反应堆压力容器焊缝超声检测技术。此反应堆压力容器超声检测技术,能有效地进行缺陷探测和缺陷定量,并通过了英国验证中心的第三方独立验证,满足核电站役前和在役检查规范(RSE-M 1997)的超声检测技术要求。

  9. Flexible solution of the fixturing problem in sheet metal laser butt welding (United States)

    Olsen, Flemming O.


    In 20 years laser welding of sheet metal has been demonstrated as a possible high-tech metal joining process. However, the major obstacle to the introduction of laser welding in for example car body manufacturing has been and is the fixturing problem. In case of laser butt welding of 0.5 - 1 mm thick steel sheets, the maximum acceptable gab between the sheets to be welded is in the range of 40 - 50 micrometer. Out of this demand two major problems arise: (1) the high precision required in weld preparation in terms of precise shape of the two sheets to be welded. (2) the problem of maintaining a narrow gab under welding, where thermal distortions, even though they are relatively small in this process, still will open the gap as the welding beam proceeds along the seam. In this paper a unique technique to overcome these problems will be described. The results of the experimental work described in this paper demonstrates the technique in 2D welding, where high quality butt welds has been demonstrated with virtually no clamping forces applied by utilizing a special seam preparation technique. Possibilities in car body manufacturing and other 3D sheet metal assembly by means of the flexible laser welding technique will be discussed.

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

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Fei; Wang, Chun Ming; Wang, Ya Jun [Huazhong Univ. of Science and Technology, Wuhan (China); Xu, Dao Rong; Wu, S.C.; Sun, Qin De [Heifei Univ. of Technology, Hefei (China)


    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 {alpha} 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.

  11. 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


    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.

  12. Simulation of the welding of irradiated materials

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Hua Tay


    Helium was uniformly implanted using the ''tritium trick'' technique to levels of 0.18, 2.5, 27, 105 and 256 atomic part per million (appm) for type 316 stainless steel, and 0.3 and 1 appm for Sandvik HT-9 (12 Cr-1MoVW). Both full penetration as well as partial penetration welds were then produced on control and helium-containing materials using the autogenous gas tungsten arc (GTA) welding process under full constraint conditions. For full penetration welds, both materials were successfully welded when they contained less than 0.3 appm helium. However, welds of both materials, when containing greater than 1 appm helium, were found to develop cracks during cooling of the weld. Transmission and scanning electron microscopy indicated that the HAZ cracking was caused by the growth and coalescence of grain boundary (GB) helium bubbles. This cracking occurred as a result of the combination of high temperatures and high shrinkage tensile stresses. The cracking in the fusion zone was found to result from the precipitation of helium along dendrite interfaces. A model based on the kinetics of diffusive cavity growth is presented to explain the observed results. The model proposes a helium bubble growth mechanism which leads to final intergranular rupture in the heat-affected zone. Results of the present study demonstrate that the use of conventional fusion welding techniques to repair materials degraded by exposure to irradiation environments may be difficult if the irradiation results in the generation of helium equal to or greater than 1 appm.

  13. Effects of Sealing Run Welding with Defocused Laser Beam on the Quality of T-joint Fillet Weld (United States)

    Unt, Anna; Poutiainen, Ilkka; Salminen, Antti

    Fillet weld is the predominant weld type used for connecting different elements e.g. in shipbuilding, offshore and bridge structures. One of prevalent research questions is the structural integrity of the welded joint. Post weld improvement techniques are being actively researched, as high stress areas like an incomplete penetration on the root side or fluctuations in penetration depth cannot be avoided. Development of laser and laser-arc hybrid welding processes have greatly contributed to increase of production capacity and reduction of heat-induced distortions by producing single pass full penetration welds in thin- and medium thickness structural steel parts. Present study addresses the issue of how to improve the quality of the fillet welds by welding the sealing run on the root side with defocused laser beam. Welds having incomplete or excessive penetration were produced with several beam angles and laser beam spot sizes on surface. As a conclusion, significant decrease or even complete elimination of the seam irregularities, which act as the failure starting points during service, is achieved.

  14. Analysis of Friction Stir Welding of Aluminum Alloys and Optimization of Welding Parameters for Maximum Tensile Strength

    Directory of Open Access Journals (Sweden)

    Prof. S. K. Aditya


    Full Text Available The Friction Stir Welding (FSW process is an innovative technique to join metals in the plastic state thus not reaching the liquid state as it happen in traditional welding processes. This feature of the FSW proved that a modification can be done on the fatigue behavior and strength of the welding joints so, some of the leading companies to adopted the process for the manufacturing of Automotive, Locomotive, Shipping & Aerospace. The FSW is a variant of the linear friction welding process in which the material is being welded without bulk melting. The FSW parameters such as tool Rotational speed, Welding speed, Axial Force, Tool tilt angle, Welding Tool Shoulder Diameter, and Welded Plate thickness play a major role in determining the properties like Tensile strength, hardness, residual stress, HAZ etc. of the joints. Our objective is to optimize the welding parameters to achieve Max. Tensile Strength of Aluminium Alloys (especially on AA-2xxx, AA-5xxx under FSW. We only wish to optimize (by Taguchi and ANOVA method with three variable input parameters (Rotational speed in rpm, Translation speed in mm/min & Axial force in KN considering a cylindrical pin.

  15. Temperature control during laser vessel welding. (United States)

    Springer, T A; Welch, A J


    A technique is described for the computer control of temperature during laser vessel welding. The technique is based on the use of thermal feedback from a calibrated IR sensor. The utilization of thermalfeedback makes it possible for welding to be performed at a quasiconstant temperature. An experimentalsystem based on this concept has been developed and evaluated in mock anastomoses with vasculartissue. A computer simulation of laser vessel welding with a one-dimensional heat conduction model hasbeen performed. Model parameters have been adjusted so that the relative effect of laser penetrationdepth and tissue dehydration as well as the role of thermal feedback in limiting the peak surfacetemperature can be studied. The results of the mock anastomoses are discussed in light of the computer model.

  16. Preparation of Ti-based amorphous brazing alloy

    Institute of Scientific and Technical Information of China (English)

    ZOU Jia-sheng; JIANG Zhi-guo; XU Zhi-rong; CHEN Guang


    A new kind of amorphous active brazing alloy foil with the composition of Ti40Zr25Ni15Cu20 was successfully synthesized using melt spinning in roll forging machine in argon atmosphere. The amorphous structure and composition were examined by X-ray diffraction, differential thermal analysis and energy dispersive X-ray detector. The results show that the Ti40Zr25Ni15Cu20 amorphous alloy foil has excellent wettability on Si3N4 ceramic and demonstrate a strong glass forming ability. The reduced glass transition temperature (Trg) and the temperature interval of supercooled liquid region before crystallization are 0.76 and 78 K, respectively.

  17. Visual sensing of weld pool in variable polarity TIG welding of aluminium alloy

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guang-jun; YAN Zhi-hong; WU Lin


    The passive visual sensing method was successfully applied to monitor the weld pool in TIG welding of aluminium alloy.In order to reduce the disturbance from the arc and acquire clear image, two techniques were used: one was the own-developed computer-controlled variable polarity power(VPP), the other was the composite filter technology. The VPP source did not have high-frequency electromagnetic interference from arc stabilizer in traditional AC welding power, and its output current wave was controlled by computer, so the imaging current and the imaging time could be adjusted easily. Filter spectral window was identified at 650 nm by analyzing the measured arc light spectral distribution. At the end, the high quality and clear images of welding pool of aluminium alloy were successfully acquired at low imaging current.

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

    Directory of Open Access Journals (Sweden)

    Umasankar Das,


    Full Text Available 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 aluminum alloys particularly because of their fine strength to weight ratio. However in compare with steels they represent welding difficulties and also lower ductility. In last years it has been observed that Friction Stir Welding (FSW method represents better microstructure and mechanical properties than conventional methods in welding aluminum alloys. It has been widely investigated for mostly low melting materials, such as Al, Mg and Cu alloys. Aluminum is the most usable material in engineering application and a lot of improvement is needed in the area of its welding. The latest works on friction stir welding of aluminum have been directed towards improving the quality of weld, reducing defects and applying the process of FSW to aluminum for specific applications. This joining technique is energy efficient, environment friendly, and versatile. In particular, it can be used to join high-strength aerospace aluminum alloys and other metallic alloys that are hard to weld by conventional fusion welding. FSW is considered to be the most significant development in metal joining in a last decade. The FSW of Aluminums and its alloys has been commercialized; and recent interest is focused on joining dissimilar materials. However, in order to commercialize the process, research studies are required to characterize and establish proper process parameters for FSW. This paper summarizes the trends and advances of this welding processes in the field of welding. Future aspects of

  19. Sturdy on Orbital TIG Welding Properties for Nuclear Fuel Test Rod

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Changyoung; Hong, Jintae; Kim, Kahye; Huh, Sungho [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    We developed a precision TIG welding system that is able to weld the seam between end-caps and a fuel cladding tube for the nuclear fuel test rod and rig. This system can be mainly classified into an orbital TIG welder (AMI, M-207A) and a pressure chamber. The orbital TIG welder can be independently used, and it consists of a power supply unit, a microprocessor, water cooling unit, a gas supply unit and an orbital weld head. In this welder, the power supply unit mainly supplies GTAW power for a welding specimen and controls an arc starting of high frequency, supping of purge gas, arc rotation through the orbital TIG welding head, and automatic timing functions. In addition, the pressure chamber is used to make the welded surface of the cladding specimen clean with the inert gas filled inside the chamber. To precisely weld the cladding tube, a welding process needs to establish a schedule program for an orbital TIG welding. Therefore, the weld tests were performed on a cladding tube and dummy rods under various conditions. This paper describes not only test results on parameters of the purge gas flow rates and the chamber gas pressures for the orbital TIG welding, but also test results on the program establishment of an orbital TIG welding system to weld the fuel test rods. Various welding tests were performed to develop the orbital TIG welding techniques for the nuclear fuel test rod. The width of HAZ of a cladding specimen welded with the identical power during an orbital TIG welding cycle was continuously increased from a welded start-point to a weld end-point because of heat accumulation. The welding effect of the PGFR and CGP shows a relatively large difference for FSS and LSS. Each hole on the cladding specimens was formed in the 1bar CGP with the 20L/min PGFR but not made in the case of the PGFR of 10L/min in the CGP of 2bar. The optimum schedule program of the orbital TIG welding system to weld the nuclear fuel test rod was established through the program

  20. Low temperature impact testing of welded structural wrought iron (United States)

    Rogers, Zachary

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

  1. Simulation of welding

    Institute of Scientific and Technical Information of China (English)

    Chuan-Song WU; Michael RETHMEIER; Christopher SCHWENK


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

  2. Interfacial metallurgy study of brazed joints between tungsten and fusion related materials for divertor design

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yuxuan, E-mail: [Department of Mechanical and Aerospace Engineering, University of Strathclyde, Glasgow G1 1XJ (United Kingdom); Galloway, Alexander; Wood, James; Robbie, Mikael Brian Olsson; Easton, David [Department of Mechanical and Aerospace Engineering, University of Strathclyde, Glasgow G1 1XJ (United Kingdom); Zhu, Wenzhong [School of Engineering, University of the West of Scotland, Paisley PA1 2BE (United Kingdom)


    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.

  3. Resistance spot welding and weldbonding of advanced high strength steels

    Energy Technology Data Exchange (ETDEWEB)

    Weber, G.; Gaul, H.; Rethmeier, M. [BAM Federal Institute for Materials Research and Testing, Berlin (Germany). Div. V.5 ' ' Safety of Joined Components' ' ; Thommes, H.; Hahn, O. [Paderborn Univ. (Germany). Fakultaet fuer Maschinenbau


    The resistance spot welding procedure is one of the most important joining techniques in lightweight car body shell mass production. Especially for newly developed high strength multiphase steels, also called advanced high strength steels (AHSS), and ultra high strength steels (UHSS), this joining technique has more advantages than other thermal and mechanical joining procedures for thin steel sheets. Additionally, the technique of adhesive bonding and its combination with the technique of resistance spot welding called weldbonding becomes more and more important. One of the targets of the contribution is to show the influence of joined advanced high strength steels on the process reliability for both the resistance spot welding process and the weldbonding process. Based on welding current ranges and on results of electrode wear tests, statements concerning the resistance spot weldability of some special AHSS will be given. The mechanical behaviour of spot welded and weldbonded joints for different AHSS will be studied. Furthermore, some statements regarding the fracture behaviour, the hardness and the fatigue behaviour of both spot welded and weldbonded joints for different AHSS will be given. Finally, some results on the mechanical properties of spot welded and weldbounded joints under corrosive attacks with be discussed. (orig.)

  4. Alternating-Polarity Arc Welding (United States)

    Schwinghamer, R. J.


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

  5. Vacuum Gas Tungsten Arc Welding (United States)

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


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

  6. The effect of welding fixtures on welding distortions



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

  7. Multispot fiber laser welding

    DEFF Research Database (Denmark)

    Schutt Hansen, Klaus

    This dissertation presents work and results achieved in the field of multi beam fiber laser welding. The project has had a practical approach, in which simulations and modelling have been kept at a minimum. Different methods to produce spot patterns with high power single mode fiber lasers have...... been possible to control the welding width in incremental steps by adding more beams in a row. The laser power was used to independently control the keyhole and consequently the depth of fusion. An example of inline repair of a laser weld in butt joint configuration was examined. Zinc powder was placed...... in the weld causing expulsion of the melt pool. Trailing beams were applied to melt additional material and ensure a melt pool. The method showed good results for increasing tolerances to impurities and reduction of scrapped parts from blowouts during laser welding....

  8. Rheomorphism of welded tuffs (United States)

    Wolff, J. A.; Wright, J. V.


    Peralkaline welded tuffs from the islands of Gran Canaria, Canary Islands, and Pantelleria, Italy, show abundant evidence for post-depositional flow. It is demonstrated that rheomorphism, or secondary mass flowage, can occur in welded tuffs of ignimbrite and air-fall origin. The presence of a linear fabric is taken as the diagnostic criterion for the recognition of the process. Deposition on a slope is an essential condition for the development of rheomorphism after compaction and welding. Internal structures produced during rheomorphic flow can be studied by the methods of structural geology and show similar dispositions to comparable features in sedimentary slump sheets. It is shown that secondary flowage can occur in welded tuffs emplaced on gentle slopes, provided that the apparent viscosity of the magma is sufficiently low. Compositional factors favor the development of rheomorphism in densely welded tuffs of peralkaline type.

  9. Microstructural Aspects in FSW and TIG Welding of Cast ZE41A Magnesium Alloy (United States)

    Carlone, Pierpaolo; Astarita, Antonello; Rubino, Felice; Pasquino, Nicola


    In this paper, magnesium ZE41A alloy plates were butt joined through friction stir welding (FSW) and Tungsten Inert Gas welding processes. Process-induced microstructures were investigated by optical and SEM observations, EDX microanalysis and microhardness measurements. The effect of a post-welded T5 heat treatment on FSW joints was also assessed. Sound joints were produced by means of both techniques. Different elemental distributions and grain sizes were found, whereas microhardness profiles reflect microstructural changes. Post-welding heat treatment did not induce significant alterations in elemental distribution. The FSW-treated joint showed a more homogeneous hardness profile than the as-welded FSW joint.

  10. Studies on corrosion protection of laser hybrid welded AISI 316 by laser remelting

    DEFF Research Database (Denmark)

    Olsen, Flemming Ove; Ambat, Rajan; Rasmussen, A.J.


    laser surface melting on microstructure and corrosion behaviour of AISI 316L welds. Welding and laser treatment parameters were varied. General corrosion behaviour of the weld and laser treated surface was characterised using a gel visualization test. The local electrochemistry of the weld and laser...... treated surface was investigated using a novel micro electrochemical technique with a tip resolution of ~1 mm. Results show that hybrid laser welding of 316L has increased corrosion susceptibility probably as a result of grain boundary carbide formation. However a suitable post laser treatment could...

  11. Vacuum Brazing of Beryllium Copper Components for the National Ignition Facility

    Energy Technology Data Exchange (ETDEWEB)

    Tyhurst, C.C.; Cunningham, M.A.


    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. 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


    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.

  13. A Compendium of Brazed Microstructures For Fission Power Systems Applications (United States)

    Locci, Ivan E.; Bowman, Cheryl L.


    NASA has been supporting design studies and technology development for fission-based power systems that could provide power to an outpost on the Moon, Mars, or an asteroid. Technology development efforts have included fabrication and evaluation of components used in a Stirling engine power conversion system. This investigation is part of the development of several braze joints crucial for the heat exchanger transfer path from a hot-side heat exchanger to a Stirling engine heat acceptor. Dissimilar metal joints are required to impart both mechanical strength and thermal path integrity for a heater head of interest. Preliminary design work for the heat exchanger involved joints between low carbon stainless steel to Inconel 718, where the 316L stainless steel would contain flowing liquid metal NaK while Inconel 718, a stronger alloy, would be used as structural reinforcement. This paper addressed the long-term microstructural stability of various braze alloys used to join 316L stainless steel heater head to the high conductivity oxygen-free copper acceptor to ensure the endurance of the critical metallic components of this sophisticated heat exchanger. The bonding of the 316L stainless steel heater head material to a copper heat acceptor is required to increase the heat-transfer surface area in contact with flowing He, which is the Stirling engine working fluid.

  14. Electron Beam Welding of Thick Copper Material

    Energy Technology Data Exchange (ETDEWEB)

    Broemssen, Bernt von [IVF Industriforskning och utveckling AB, Stockholm (Sweden)


    The purpose of this study was to review the two variants of the Electron Beam Welding (EBW) processes developed (or used) by 1- SKB, Sweden with assistance from TWI, England and 2 - POSIVA, Finland with assistance from Outokumpu, Finland. The aim was also to explain the principle properties of the EBW method: how it works, the parameters controlling the welding result but also giving rise to benefits, and differences between the EBW variants. The main conclusions are that both SKB and POSIVA will within a few years succeed to qualify their respective EBW method for welding of copper canisters. The Reduced Pressure EBW that SKB use today seems to be very promising in order to avoid root defects. If POSIVA does not succeed to avoid root defects with the high vacuum method and the beam oscillation technique it should be possible for POSIVA to incorporate the Reduced Pressure technique albeit with significant changes to the EBW equipment. POSIVA has possibly an advantage over SKB with the beam oscillation technique used, which gives an extra degree of freedom to affect the weld quality. The beam oscillation could be of importance for closing of the keyhole. Before EBW of lids, the material certification showing the alloy content (specifying min and max impurity percentages) and the mechanical properties should be checked. The welded material needs also to be tested for mechanical properties. If possible the weld should have a toughness level equal to that of the unwelded parent material. Specifically some conclusions are reported regarding the SKB equipment. Suggestions for further development are also given in the conclusion chapter.

  15. Development of Welding and Instrumentation Technology for Nuclear Fuel Test Rod

    Energy Technology Data Exchange (ETDEWEB)

    Joung, Chang Young; Ahn, Sung Ho; Heo, Sung Ho; Hong, Jin Tae; Kim, Ka Hye [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)


    It is necessary to develop various types of welding, instrumentation and helium gas filling techniques that can conduct TIG spot welding exactly at a pin-hole of the end-cap on the nuclear fuel rod to fill up helium gas. The welding process is one of the most important among the instrumentation processes of the nuclear fuel test rod. To manufacture the nuclear fuel test rod, a precision welding system needs to be fabricated to develop various welding technologies of the fuel test rod jointing the various sensors and end-caps on a fuel cladding tube, which is charged with fuel pellets and component parts. We therefore designed and fabricated an orbital TIG welding system and a laser welding system. This paper describes not only some experiment results from weld tests for the parts of a nuclear fuel test rod, but also the contents for the instrumentation process of the dummy fuel test rod installed with the C-type T. C. A dummy nuclear fuel test rod was successfully fabricated with the welding and instrumentation technologies acquired with various tests. In the test results, the round welding has shown a good weldability at both the orbital TIG welding system and the fiber laser welding system. The spot welding to fill up helium gas has shown a good welding performance at a welding current of 30A, welding time of 0.4 sec and gap of 1 mm in a helium gas atmosphere. The soundness of the nuclear fuel test rod sealed by a mechanical sealing method was confirmed by helium leak tests and microstructural analyses.

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

    NARCIS (Netherlands)

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


    Described is a method of automatically welding pipes, comprising welding with a pulsation welding current and monitoring, by means of a sensor, the variations occurring in the arc voltage caused by weld pool oscillations. The occurrence of voltage variations with only frequency components below 100

  17. Guidelines for Friction Stir Welding (United States)


    in a large void at the termination point of the weld, the effects the exit hole will have on structural integrity must be considered. The...3.6 Cavity. A void -type discontinuity within a solid-state weld. See Figure 3.4. 3.7 Complex weld joint. A continuous weld...except as affected by corner radii. 3.61 Underfill . A depression resulting when the weld face is below the adjacent parent material surface. See

  18. Laser forming and welding processes

    CERN Document Server

    Yilbas, Bekir Sami; Shuja, Shahzada Zaman


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

  19. Thermoplastic welding apparatus and method

    Energy Technology Data Exchange (ETDEWEB)

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


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

  20. Automatic welding quality classification for the spot welding based on the Hopfield associative memory neural network and Chernoff face description of the electrode displacement signal features (United States)

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


    To develop an automatic welding quality classification method for the spot welding based on the Chernoff face image created by the electrode displacement signal features, an effective pattern feature extraction method was proposed by which the Chernoff face images were converted to binary ones, and each binary image could be characterized by a binary matrix. According to expression categories on the Chernoff face images, welding quality was classified into five levels and each level just corresponded to a kind of expression. The Hopfield associative memory neural network was used to build a welding quality classifier in which the pattern feature matrices of some weld samples with different welding quality levels were remembered as the stable states. When the pattern feature matrix of a test weld is input into the classifier, it can be converged to the most similar stable state through associative memory, thus, welding quality corresponding to this finally locked stable state can represent the welding quality of the test weld. The classification performance test results show that the proposed method significantly improves the applicability and efficiency of the Chernoff faces technique for spot welding quality evaluation and it is feasible, effective and reliable.

  1. Problems in laser repair welding of polished surfaces

    Directory of Open Access Journals (Sweden)

    A. Skumavc


    Full Text Available This paper presents problems in laser repair welding of the tools for injection moulding of plastics and light metals. Tools for injection moulding of the car headlamps are highly polished in order to get a desirable quality of the injected part. Different light metals, glasses, elastomers, thermoplastics and thermosetting polymers are injected into the die cavity under high pressures resulting in the surface damages of the tool. Laser welding is the only suitable repair welding technique due to the very limited sputtering during deposition of the filler metal. Overlapping of the welds results in inhomogeneous hardness of the remanufactured surface. Results have shown strong correlation between hardness and surface waviness after final polishing of the repair welded surface.

  2. Autofocus imaging: Experimental results in an anisotropic austenitic weld (United States)

    Zhang, J.; Drinkwater, B. W.; Wilcox, P. D.; Hunter, A.


    The quality of an ultrasonic array image, especially for anisotropic material, depends on accurate information about acoustic properties. Inaccuracy of acoustic properties causes image degradation, e.g., blurring, errors in locating of reflectors and introduction of artifacts. In this paper, for an anisotropic austenitic steel weld, an autofocus imaging technique is presented. The array data from a series of beacons is captured and then used to statistically extract anisotropic weld properties by using a Monte-Carlo inversion approach. The beacon and imaging systems are realized using two separated arrays; one acts as a series of beacons and the other images these beacons. Key to the Monte-Carlo inversion scheme is a fast forward model of wave propagation in the anisotropic weld and this is based on the Dijkstra algorithm. Using this autofocus approach a measured weld map was extracted from an austenitic weld and used to reduce location errors, initially greater than 6mm, to less than 1mm.

  3. Inspection of plastic weld joints with terahertz imaging (United States)

    Wietzke, S.; Krumbholz, N.; Jördens, C.; Baudrit, B.; Bastian, M.; Koch, M.


    Polymers cover the whole range from commodities to high-tech applications. Plastic products have also gained in importance for construction purposes. This draws the attention to joining techniques like welding. Common evaluation of the weld quality is mostly mechanical and destructive. Existing non-destructive techniques are mostly not entirely reliable or economically inefficient. Here, we demonstrate the potential of terahertz time-domain spectroscopy imaging as a non-destructive testing tool for the inspection of plastic weld joints. High-density polyethylene sheets welded in a lap joint with varying quality serve as samples for terahertz transmission measurements. Imperfections within the weld contact area can clearly be detected by displaying the transmitted intensity in a limited frequency range. Contaminations such as metal or sand are identified since they differ significantly from the polymer in the terahertz image. Furthermore, this new and promising technique is capable of detecting the boundaries of a weld contact area. Aside from revealing a contrast between a proper weld joint and no material connection, the size of an air gap between two plastic sheets can be determined by considering the characteristic frequency-dependent transmission through the structure: The spectral positions of the maxima and minima allow for the calculation of the air layer thickness.

  4. Lamb Wave Line Sensing for Crack Detection in a Welded Stiffener


    Yun-Kyu An; Jae Hong Kim; Hong Jae Yim


    This paper proposes a novel Lamb wave line sensing technique for crack detection in a welded stiffener. The proposed technique overcomes one of the biggest technical challenges of Lamb wave crack detection for real structure applications: crack-induced Lamb waves are often mixed with multiple reflections from complex waveguides. In particular, crack detection in a welded joint, one of the structural hot spots due to stress concentration, is accompanied by reflections from the welded joint as...

  5. Effects of the laser beam superficial heat treatment on the gas Tungsten arc Ti-6al-4v welded metal microstructure (United States)

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


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

  6. Active Metal Brazing and Characterization of Brazed Joints in C-C and C-SiC Composites to Copper-Clad-Molybdenum System (United States)

    Singh, M.; Asthana, R.


    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.

  7. Model of Layered Weld Formation Under Narrow Gap Pulse Welding (United States)

    Krampit, A. G.


    The model parameters of narrow gap pulse welding can be divided into input, internal and output ones. The breadth of gap, that is, clearance breadth between upright edges is one of key parameters securing high quality of a weld joint. The paper presents theoretical outcomes for the model of layered weld formation under narrow gap pulse welding. Based on these studies is developed model of processes, which occur in the weld pool under pulse grove welding. It comprises the scheme of liquid metal motion in the weld pool, scheme of fusion with the side edge and in the bottom part, and the scheme of welding current impulse effect on the structure of a weld joint.

  8. Weld overlay cladding with iron aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, G.M. [Oak Ridge National Lab., TN (United States)


    The author has established a range of compositions for these alloys within which hot cracking resistance is very good, and within which cold cracking can be avoided in many instances by careful control of welding conditions, particularly preheat and postweld heat treatment. For example, crack-free butt welds have been produced for the first time in 12-mm thick wrought Fe{sub 3}Al plate. Cold cracking, however, still remains an issue in many cases. The author has developed a commercial source for composite weld filler metals spanning a wide range of achievable aluminum levels, and are pursuing the application of these filler metals in a variety of industrial environments. Welding techniques have been developed for both the gas tungsten arc and gas metal arc processes, and preliminary work has been done to utilize the wire arc process for coating of boiler tubes. Clad specimens have been prepared for environmental testing in-house, and a number of components have been modified and placed in service in operating kraft recovery boilers. In collaboration with a commercial producer of spiral weld overlay tubing, the author is attempting to utilize the new filler metals for this novel application.

  9. Characterisation of fume from hyperbaric welding operations

    Energy Technology Data Exchange (ETDEWEB)

    Ross, John A S; Semple, Sean [Environmental and Occupational Medicine, University of Aberdeen (United Kingdom); Duffin, Rodger [ELEGI Colt Laboratory, University of Edinburgh (United Kingdom); Kelly, Frank [Lung Biology Group, Kings College, University of London (United Kingdom); Seldmann, Joerg; Raab, Andrea, E-mail: [Trace Element Speciation Laboratory, University of Aberdeen (United Kingdom)


    We report preliminary work characterising dust from hyperbaric welding trials carried out at increased pressure in a helium and oxygen atmosphere. Particle size and concentration were measured during welding. Samples for quartz and metal analysis and toxicity assessment were taken from a filter in the local fume extraction system. The residue of dust after metal extraction by nitric acid in hydrogen peroxide predominantly a non-metallic white powder assumed to be dust from welding rod coatings and thermal insulation material. Metallic analysis showed predominantly calcium, from the welding rod coating, and period 4 transition metals such as iron, manganese, magnesium and titanium (inductively coupled mass spectrometry, Agilent 7500c). The presence of zirconium indicated a contribution from grinding. The fume was nanoparticulate in nature with a mean particle diameter of 20-30 nm (MSI Inc WPS 1000XP). It showed an intermediate level of oxidative potential regarding the low-molecular weight respiratory tract lining fluid antioxidants ascorbate and glutathione and caused release of the inflammatory marker IL-8 in a human lung A 549 epithelial cell culture with no indication of cytotoxicity. The study findings have strong implications for the measurement techniques needed to assess fume exposure in hyperbaric welding and the provision of respiratory protection.

  10. Friction Stir Welding of Shipbuilding Steel with Primer

    Directory of Open Access Journals (Sweden)

    José Azevedo


    Full Text Available Abstract Friction Stir Welding has proven its merits for welding of aluminium alloys and is focused in expanding its material database to steel and titanium and also to assess new joint configurations. The use of welded structures in shipbuilding industry has a long tradition and continuously seeks for innovation in terms of materials and processes maintaining, or even, reducing costs. Several studies have been performed in the past years on FSW of steel. However, just recently were reported defect-free welds, free of martensite with stable parameters in steel without Primer. FSW of steel with primer has not been addressed. This work aims to fulfil a knowledge gap related to the use of friction stir for welding shipbuilding steel by analysing the effect of welding parameters on the metallurgical characteristics and mechanical properties of welds obtained with an innovative FSW tool in joining steel plates with a primer. Welds were performed in 4mm thick GL-A36 steel plates painted with a zinc based primer followed by a detailed microscopic, chemical and mechanical analysis. The results that matching fatigue properties are obtained using this technique, in FSW of shipbuilding steel with Primer.

  11. Exposure to inhalable, respirable, and ultrafine particles in welding fume. (United States)

    Lehnert, Martin; Pesch, Beate; Lotz, Anne; Pelzer, Johannes; Kendzia, Benjamin; Gawrych, Katarzyna; Heinze, Evelyn; Van Gelder, Rainer; Punkenburg, Ewald; Weiss, Tobias; Mattenklott, Markus; Hahn, Jens-Uwe; Möhlmann, Carsten; Berges, Markus; Hartwig, Andrea; Brüning, Thomas


    This investigation aims to explore determinants of exposure to particle size-specific welding fume. Area sampling of ultrafine particles (UFP) was performed at 33 worksites in parallel with the collection of respirable particles. Personal sampling of respirable and inhalable particles was carried out in the breathing zone of 241 welders. Median mass concentrations were 2.48 mg m(-3) for inhalable and 1.29 mg m(-3) for respirable particles when excluding 26 users of powered air-purifying respirators (PAPRs). Mass concentrations were highest when flux-cored arc welding (FCAW) with gas was applied (median of inhalable particles: 11.6 mg m(-3)). Measurements of particles were frequently below the limit of detection (LOD), especially inside PAPRs or during tungsten inert gas welding (TIG). However, TIG generated a high number of small particles, including UFP. We imputed measurements welding fume. Concentrations were mainly predicted by the welding process and were significantly higher when local exhaust ventilation (LEV) was inefficient or when welding was performed in confined spaces. Substitution of high-emission techniques like FCAW, efficient LEV, and using PAPRs where applicable can reduce exposure to welding fume. However, harmonizing the different exposure metrics for UFP (as particle counts) and for the respirable or inhalable fraction of the welding fume (expressed as their mass) remains challenging.

  12. Note: Resistance spot welding using a microgripper (United States)

    Hwang, G.; Podrzaj, P.; Hashimoto, H.


    Interest in thin-film nanostructures as building blocks for nanoelectronics and nanoelectromechanical systems (NEMS) is increasing. Resistance spot welding (RSW) on a nano or micro scale can play a significant role; similar to that of its macro counterpart for forming connections in device assembly processes. This Note presents a novel micron scale RSW technique using a microgripper as mobile spot welding electrodes to assemble ultra-thin film nanostructures. As an example, assembly of three-dimensional helical nanobelt (HNB) based device was successfully demonstrated using the proposed system. The spot-welding process was fully monitored by the built-in capacitive micro force sensor of the microgripper. Experiments show that RSW, using the microgripper, provides a stable electrical contact with sufficient mechanical strength for the construction of devices such as HNB based devices demonstrated here.

  13. Computational Analysis and Experimental Validation of the Friction-Stir Welding Behaviour of Ti-6Al-4V (United States)


    investigated using various optical and scanning electron microscopy techni- ques, while the weld properties were investigated using microhardness ...measurements, transverse and all-weld tensile testing techniques, as well as surface profilometry. The main findings/observations made in refer- ences [16...formation in the centre of the weld. 9. Material microhardness within the weld nugget is typically found to be affected by the workpiece thickness

  14. Evaluation of the adhesion strength of diamond films brazed on K-10 type hard metal

    Directory of Open Access Journals (Sweden)

    Santos Sérgio Ivan dos


    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.

  15. 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


    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

  16. Researches and studies regarding brazed aluminium alloys microstructure used in aeronautic industry

    Directory of Open Access Journals (Sweden)

    A. Dimitrescu


    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.

  17. Nano-Phase Powder Based Exothermic Braze Repair Technology For RCC Materials Project (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...

  18. Nano-Phase Powder Based Exothermic Braze Repair Technology For RCC Materials Project (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 itself...

  19. Compatibility of Au-Cu-Ni braze alloy with NH3 (United States)

    Diaz, V., Jr.


    Tests show that Gold-Copper-Nickel alloy is compatible with ammonia systems. Joining tubes by brazing has advantages such as reducing chances of excessive grain growth in base metal, saving weight, and cleanliness.

  20. Characterization of the mechanical properties and structural integrity of T-welded connections repaired by grinding and wet welding

    Energy Technology Data Exchange (ETDEWEB)

    Terán, G., E-mail: [Instituto Mexicano del Petróleo, Eje central Lázaro Cárdenas 152, Col. San Bartolo Atepehuacan, México D.F. CP 07730, México (Mexico); Cuamatzi-Meléndez, R., E-mail: [Instituto Mexicano del Petróleo, Eje central Lázaro Cárdenas 152, Col. San Bartolo Atepehuacan, México D.F. CP 07730, México (Mexico); Albiter, A., E-mail: [Instituto Mexicano del Petróleo, Eje central Lázaro Cárdenas 152, Col. San Bartolo Atepehuacan, México D.F. CP 07730, México (Mexico); Maldonado, C., E-mail: [Instituto de Investigaciones Metalúrgicas, UMSNH, PO Box 52-B, 58000, México (Mexico); Bracarense, A.Q., E-mail: [UFMG Departamento de Engeharia Mecánica Belo Horizonte, MG (Brazil)


    This paper presents an experimental methodology to characterize the structural integrity and mechanical properties of repaired T-welded connections using in fixed offshore structures. Grinding is employed to remove localized damage like cracking and corrosion and subsequent wet welding can be used to fill the grinded material. But it is important to define the grinding depth and profile in order to maintain structural integrity during the repair. Therefore, in this work different grinding depths were performed, for damage material removal, at the weld toe of the T-welded connections. The grinding was filled by wet welding in a hyperbaric chamber, simulating three different water depths: 50 m, 70 m and 100 m. The electrodes were coated with vinilic varnish, which is cheap and easy to apply. The characterization of the mechanical properties of the T-welded connections was done with standard tensile, hardness and Charpy tests; microstructure and porosity analysis were also performed. The samples were obtained from the welded connections in regions of the wet weld beads. The test results were compared with the mechanical properties of the T-welded connections welded in air conditions performed by other authors. The results showed that the wet welding technique performed in this work produced good mechanical properties of the repaired T-welded connection. The mechanical properties, measured in wet conditions, for 6 mm grinding depth, were similar for the 3 different water depths measured in air conditions. But for 10 mm grinding depth, the values of the mechanical properties measured in wet conditions were quite lower than that for air conditions for the 3 water depths. However a porosity analysis, performed with a Scanning Electronic Microscopy (SEM), showed that the level of porosity in the resulted wet weld beads is in the range of that published in the literature and some samples revealed lower level of porosity. The main resulting microstructure was polygonal

  1. Review of Welding Terminology

    Directory of Open Access Journals (Sweden)

    Angelika Petrėtienė


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

  2. Thermal stir welding apparatus (United States)

    Ding, R. Jeffrey (Inventor)


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

  3. Thermal stir welding process (United States)

    Ding, R. Jeffrey (Inventor)


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

  4. Fusion Welding Research. (United States)


    RD-AlSO 253 FUSION WELDING RESEARCH(U) MASSACHUSETTS INST OF TECH L/I CAMBRIDGE DEPT OF MATERIALS SCIENCE AND ENGINEERING T W EAGAR ET AL. 30 RPR 85...NUMBER 12. GOV’ ACCESSION NO. 3. RECICIE-S CATALOG NUMBER 4. T TL V nd Subtitle) S. P OFRPR PERIOD COVERED 5t h A~nnual Technical Report Fusion Welding ...research S on welding processes. Studies include metal vapors in the arc, development of a high speed infrared temperature monitor, digital signal

  5. A preliminary study on filler metals for vacuum brazing of Al/Ti

    Institute of Scientific and Technical Information of China (English)

    朱颖; 赵鹏飞; 康慧; 胡刚; 曲平


    In this paper, nine new filler metals contained Sn and Ga based on Al-11.5Si have been designed for vacuum brazing of Al/Ti. It is found that the addition of Sn and Ga can lower the solidus of filler metal, change the structure of intermetallic compound formed in the joint during brazing, and enhance the strength of joint. But the detail mechanism need further research.

  6. [Determination of Ag, Cu, Zn and Cd in silver brazing filler metals by ICP-AES]. (United States)

    Yang, X


    A method of simultaneous and direct determination for Ag, Cu, Zn and Cd in silver brazing filler metals by ICP-AES is reported. The spectral interferences and effect of acidity have been investigated. Working conditions were optimized. The method has been applied to the analysis of silver brazing filler metals with RSD of 4-7% and recovery of 94-105%. This method was accurate, simple and rapid.

  7. Mechanical properties of Inconel 718 and Nickel 201 alloys after thermal histories simulating brazing and high temperature service (United States)

    James, W. F.


    An experimental investigation was made to evaluate two nickel base alloys (Nickel-201 and Inconel-718) in three heat treated conditions. These conditions were: (1) annealed; (2) after thermal exposure simulating a braze cycle; and (3) after a thermal exposure simulating a braze cycle plus one operational lifetime of high temperature service. For the Nickel-201, two different braze cycle temperatures were evaluated. A braze cycle utilizing a lower braze temperature resulted in less grain growth for Nickel-201 than the standard braze cycle used for joining Nickel-201 to Inconel-718. It was determined, however, that Nickel-201, was marginal for temperatures investigated due to large grain growth. After the thermal exposures described above, the mechanical properties of Nickel-201 were degraded, whereas similar exposure on Inconel-718 actually strengthened the material compared with the annealed condition. The investigation included tensile tests at both room temperature and elevated temperatures, stress-rupture tests, and metallographic examination.

  8. Investigation of the corrosion performance of different braze fillers fused onto stainless steel type 1.4401 (UNS S31600)

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, C.; Eklund, T.; Persson, O. [Alfa Laval Corporate AB, Tumba (Sweden)


    Corrosion measurements were performed on a new iron based braze filler, AlfaNova{sup 1} developed by Alfa Laval. The braze filler was fused onto stainless steel type EN 1.4401 (UNS S31600). The susceptibility to general corrosion, intergranular corrosion and pitting corrosion was evaluated by gravimetrical and electrochemical methods as well as metallographical examination of the samples. Different sample configurations were utilised, which simulate the geometry of a braze joint in a plate heat exchange. The results were compared with a selection of commercial nickel-based braze fillers. It was shown that the newly developed iron-based braze filler had similar corrosion resistance as the commercially available nickel-based fillers. It was seen that the precipitation of intermetallic phases due to melting point depressants had a governing effect on the corrosion resistance of the braze joint. (orig.)

  9. Study on vacuum induction brazing of SiCp/LY12 composite using Al-Cu-Si-Mg filler metal

    Institute of Scientific and Technical Information of China (English)

    邹家生; 许如强; 赵其章; 陈铮


    The vacuum induction brazing of SiC particulate reinforced LY12 alloy matrix composite using Al-28Cu-5Si-2Mg filler metal has been carried out. The micrograph of the joint interface was observed by scanning electron microscopy. The joint strength was determined by shear tests. The results show that brazing temperature, holding time, SiC particle volume percentage and post heat treatment influence joint strength. SiC particles happen in the brazing seam and the distribution of SiC particles in the joint is not uniform. Particle-poor zones in the joint exist near the base metal, and particle concentrate zones exist in the center of the brazing seam. In addition, the failure of the composite is predominantly initiated by the rooting of SiC particle in the brazing seam and the micro-crack expanded along the brazing seam with low energy.

  10. Hybrid laser-arc welding

    DEFF Research Database (Denmark)

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

  11. Application of artificial neural network to predict Vickers microhardness of AA6061 friction stir welded sheets

    Institute of Scientific and Technical Information of China (English)

    Vahid Moosabeiki Dehabadi; Saeede Ghorbanpour; Ghasem Azimi


    The application of friction stir welding (FSW) is growing owing to the omission of difficulties in traditional welding processes. In the current investigation, artificial neural network (ANN) technique was employed to predict the microhardness of AA6061 friction stir welded plates. Specimens were welded employing triangular and tapered cylindrical pins. The effects of thread and conical shoulder of each pin profile on the microhardness of welded zone were studied using tow ANNs through the different distances from weld centerline. It is observed that using conical shoulder tools enhances the quality of welded area. Besides, in both pin profiles threaded pins and conical shoulders increase yield strength and ultimate tensile strength. Mean absolute percentage error (MAPE) for train and test data sets did not exceed 5.4% and 7.48%, respectively. Considering the accurate results and acceptable errors in the models’ responses, the ANN method can be used to economize material and time.

  12. Characterization of Microstructure and Mechanical Properties of Resistance Spot Welded DP600 Steel

    Directory of Open Access Journals (Sweden)

    Ali Ramazani


    Full Text Available 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. The microstructures observed in different sites of the welds were correlated to thermal history recorded by thermocouples in the corresponding areas. It was found that cracks initiated in the periphery region of weld nuggets with a martensitic microstructure and a pull-out failure mode was observed. It was also concluded that tempering during RSW was the main reason for hardness decrease in HAZ.

  13. Effective silver-assisted welding of YBCO blocks: mechanical versus electrical properties

    Energy Technology Data Exchange (ETDEWEB)

    Bartolome, E [Escola Universitaria Salesiana de Sarria (associated with the University Autonoma of Barcelona), Passeig Sant Joan Bosco 74, E-08017 Barcelona (Spain); Roa, J J; Segarra, M [Centro DIOPMA, Departamento Ciencia de los Materiales e IngenierIa Metalurgica, Instituto de Nanociencia y NanotecnologIa de la Universidad de Barcelona (IN2UB), Facultad de Quimica, Universidad de Barcelona, MartI i Franques 1, E-08028 Barcelona (Spain); Bozzo, B; Granados, X [Institut de Ciencia de Materials de Barcelona-CSIC, Campus UAB, E-08193 Bellaterra (Spain)


    Superconducting welding of bulk YBCO is a key technology allowing the fabrication of large, complex-shaped pieces for applications such as levitation, bearings or large magnets. Ideally, the electrical and mechanical properties of welds should be comparable to that of the joint grains. In this paper, we have investigated the correlation between the microstructural, mechanical and critical current density performances of melt-textured [001]-tilt YBCO welds fabricated by the silver welding technique. The hardness reduction across the weld, measured by nanoindentation, correlates linearly with the decrease of intergranular critical current density, measured at 77 K and self-field by magnetic Hall mapping. Remarkably, we show that high quality zero-angle welds could be fabricated with unaltered current and hardness performances across the joint, paving the way for the implementation of silver welds in large-scale systems.

  14. Resistance welding of carbon fibre reinforced polyetheretherketone composites using metal mesh and PEI film

    Institute of Scientific and Technical Information of China (English)

    闫久春; 王晓林; 秦明; 赵新英; 杨士勤


    Weldability of polyetheretherketone(PEEK) with polyetherimide(PEI) is tested. And carbon fiber reinforced PEEK laminates are resistance welded using stainless steel mesh heating element. The effects of the welding time and welding pressure on the lap shear strength of joints are investigated. Results show that PEEK can heal with PEI well in welding condition and the lap shear strength of PEEK/CF(carbon fibre) joint increases linearly with welding time, but reaches a maximum value when welding pressure ranging from 0.3MPa to 0.5MPa with constant welding time. The fracture characteristics of surface are analyzed by SEM techniques, and four types of fracture modes of lap shear joints are suggested.

  15. Simulation of hydrogen diffusion in welded joint of X80 pipeline steel

    Institute of Scientific and Technical Information of China (English)

    严春妍; 刘翠英; 张根元


    Hydrogen diffusion coefficients of different regions in the welded joint of X80 pipeline steel were measured using the electro-chemical permeation technique. Using ABAQUS software, hydrogen diffusion in X80 pipeline steel welded joint was studied in consideration of the inhomogeneity of the welding zone, and temperature-dependent thermo-physical and mechanical properties of the metals. A three dimensional finite element model was developed and a coupled thermo-mechanical-diffusion analysis was performed. Hydrogen concentration distribution across the welded joint was obtained. It is found that the postweld residual hydrogen exhibits a non-uniform distribution across the welded joint. A maximum equivalent stress occurs in the immediate vicinity of the weld metal. The heat affected zone has the highest hydrogen concentration level, followed by the weld zone and the base metal. Simulation results are well consistent with theoretical analysis.

  16. The Mechanical Behavior of Friction-Stir Spot Welded Aluminum Alloys (United States)

    Güler, Hande


    Aluminum and alloys are widely used in the automotive industry due to the light weight, good formability, and malleability. Spot welding is the most commonly used joining method of these materials, but the high current requirements and the inconsistent quality of the final welds make this process unsuitable. An alternative welding technique, the friction-stir spot welding process, can also be successfully used in joining of aluminum and alloys. In this study, 1-mm-thick AA5754 Al-alloy plates in the H-111 temper conditions were joined by friction-stir spot welding using two different weld parameters such as tool rotational speed and dwell time. Mechanical properties of the joints were obtained with extensive hardness measurements and tensile shear tests. The effect of these parameters on the failure modes of welded joints was also determined.

  17. Laser Beam Welding of Ultra-high Strength Chromium Steel with Martensitic Microstructure (United States)

    Dahmen, Martin; Janzen, Vitalij; Lindner, Stefan; Wagener, Rainer

    A new class of steels is going to be introduced into sheet manufacturing. Stainless ferritic and martensitic steels open up opportunities for sheet metal fabrication including hot stamping. Strengths of up to 2 GPa at fracture elongations of 15% can be attained through this. Welding of these materials, as a result, became a challenge. Energy-reduced welding methods with in-situ heat treatment are required in order to ensure the delicate and complex heat control. Laser beam welding is the joining technique of choice to supply minimum heat input to the fusion process and to apply efficient heat control. For two application cases, tailored blank production in as-rolled condition and welding during assembly in hot stamped condition, welding processes have been developed. The welding suitability is shown through metallurgical investigations of the welds. Crash tests based on the KS-II concept as well as fatigue tests prove the applicability of the joining method.

  18. A population-based study on welding exposures at work and respiratory symptoms. (United States)

    Lillienberg, L; Zock, J-P; Kromhout, H; Plana, E; Jarvis, D; Torén, K; Kogevinas, M


    manual welding stainless steel (PR = 1.92, 1.00-3.66). There was also an increase in the prevalence of wheeze in individuals welding painted metal (PR = 1.66, 0.99-2.78; PR = 1.83, 0.90-3.71). Welding with manual metal arc technique welding in galvanized material and stainless steel and chronic bronchitis symptoms. There was also an increased prevalence of wheeze and welding in painted metal. The results support that welding in coated material is a respiratory hazard underscoring the importance of preventive actions.


    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


    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).

  20. Chemical elements diffusion in the stainless steel components brazed with Cu-Ag alloy (United States)

    Voiculescu, I.; Geanta, V.; Vasile, I. M.; Binchiciu, E. F.; Winestoock, R.


    The paper presents the study of diffusion of chemical elements through a brazing joint, between two thin components (0.5mm) made of stainless steel 304. An experimental brazing filler material has been used for brazing stainless steel component and then the diffusion phenomenon has been studied, in terms of chemical element displacement from the brazed separation interface. The filler material is in the form of a metal rod coated with ceramic slurry mixture of minerals, containing precursors and metallic powders, which can contribute to the formation of deposit brazed. In determining the distance of diffusion of chemical elements, on both sides of the fusion line, were performed measurements of the chemical composition using electron microscopy SEM and EDX spectrometry. Metallographic analysis of cross sections was performed with the aim of highlight the microstructural characteristics of brazed joints, for estimate the wetting capacity, adherence of filler metal and highlight any imperfections. Analyzes performed showed the penetration of alloying elements from the solder (Ag, Cu, Zn and Sn) towards the base material (stainless steel), over distances up to 60 microns.