Showing papers on "Filler metal published in 2003"

Microstructure and bonding mechanism of Al/Ti bonded joint using Al–10Si–1Mg filler metal

Abstract: The microstructures and liquid state diffusion bonding mechanism of cp-Ti to 1050 Al using an Al–10.0wt.%Si–1.0wt.%Mg filler metal with 100 μm in thickness have been investigated at 620 °C under 1×10−4 Torr. The effects of bonding process parameters on microstructure of bonded joint have been analyzed by using an optical microscope, AES, scanning electron microscopy and EDS. The interfacial bond strength of Al/Ti bonded joints was measured by the single lap shear test. The results show that the bonding at the interface between Al and filler metal proceeds by wetting the Al with molten filler metal, and followed by removal of oxide layer on surface of Al. The interface between Al and filler metal moved during the isothermal solidification of filler metal by the diffusion of Si from filler metal into Al layer. The interface between Al and filler metal became curved in shape with increasing bonding time due to capillary force at grain boundaries. The bonding at the interface between Ti and filler metal proceeds by the formation of two different intermetallic compound layers, identified as Al5Si12Ti7 and Al12Si3Ti5, followed by the growth of the intermetallic compound layers. The interfacial bond strength at Al/Ti joint increased with increasing bonding time up to 25 min at 620 °C. However, the interfacial bond strength of Al/Ti joint decreased after bonding time of 25 min at 620 °C due to formation of cavities in Al near Al/intermetallic interfaces.

A mechanism for the formation of equiaxed grains in welds of aluminum–lithium alloy 2090

Abstract: In this technical note, the formation and presence of a zone of equiaxed grains (EQZ) along the fusion boundary of welded aluminum–lithium alloy 2090 using filler metals containing zirconium and lithium is presented and discussed. However, no EQZ was evident in welded joints of alloy 2090 using the commercial filler metals: aluminum alloy 2319 and 4145. Under identical conditions, aluminum–lithium alloy 2090 was fusion welded using several new filler metals containing various amounts of zirconium and lithium. Results reveal an increase in the width of the zone of equiaxed grains with an increase in zirconium and lithium content in the filler metal. A viable mechanism for the formation of equiaxed grains and its relationship to filler metal composition is highlighted.

Microstructure and bonding mechanism of Al/Ti bonded joint using

Abstract: The microstructures and liquid state diffusion bonding mechanism of cp-Ti to 1050 Al using an Al � /10.0wt.%Si � /1.0wt.%Mg filler metal with 100 mm in thickness have been investigated at 620 8C under 1 � /10 � 4 Torr. The effects of bonding process parameters on microstructure of bonded joint have been analyzed by using an optical microscope, AES, scanning electron microscopy and EDS. The interfacial bond strength of Al/Ti bonded joints was measured by the single lap shear test. The results show that the bonding at the interface between Al and filler metal proceeds by wetting the Al with molten filler metal, and followed by removal of oxide layer on surface of Al. The interface between Al and filler metal moved during the isothermal solidification of filler metal by the diffusion of Si from filler metal into Al layer. The interface between Al and filler metal became curved in shape with increasing bonding time due to capillary force at grain boundaries. The bonding at the interface between Ti and filler metal proceeds by the formation of two different intermetallic compound layers, identified as Al5Si12Ti7 and Al12Si3Ti5, followed by the growth of the intermetallic compound layers. The interfacial bond strength at Al/Ti joint increased with increasing bonding time up to 25 min at 620 8C. However, the interfacial bond strength of Al/Ti joint decreased after bonding time of 25 min at 620 8C due to formation of cavities in Al near Al/intermetallic interfaces. # 2003 Elsevier Science B.V. All rights reserved.

An investigation of ductility dip cracking in nickel-based filler materials - Part I

Abstract: Ductility dip cracking (DDC) is a solid-state, elevated temperature phenomenon that has been observed in thick-section, multipass austenitic stainless steel and nickel-based alloy weld metals where large grain size and high restraint are characteristic. The mechanism has been postulated to be the result of ductility exhaustion along the grain boundary with grain boundary sliding and the relative orientation of a grain boundary to an applied strain increasing susceptibility to DDC. Although DDC is relatively uncommon, in applications where there is low defect tolerance, its occurrence can be very costly. In Part I of this investigation, the strain-to-fracture (STF) test, a Gleeble-based test developed by Nissley and Lippold (Ref. 1), was employed to develop STF DDC susceptibility curves for one heat of Filler Metal 52 and three heats of Filler Metal 82. Filler Metal 52 was found to be more susceptible to DDC than Filler Metal 82, with Filler Metal 82 exhibiting a heat-to-heat variation in susceptibility. Additions of hydrogen and sulfur to Filler Metal 82 were also investigated and found to increase the susceptibility of the weld metal to DDC. Metallurgical analysis of the weld metal microstructures revealed contrasting grain boundary characteristics. Whereas Filler Metal 52 microstructures contained both straight and tortuous migrated grain boundary paths, Filler Metal 82 contained tortuous boundary paths only. Under low orders of strain and when oriented favorably to the applied load (45-90 deg), straight migrated grain boundary paths were found to be more conducive to DDC than tortuous boundary paths. Based on these grain boundary path differences, the STF test results revealing increased susceptibility to DDC for Filler Metal 52 are understood.

Development of hot wire TIG welding methods using pulsed current to heat filler wire – research on pulse heated hot wire TIG welding processes

Abstract: (2004). Development of hot wire TIG welding methods using pulsed current to heat filler wire – research on pulse heated hot wire TIG welding processes. Welding International: Vol. 18, No. 6, pp. 456-468.

Apparatus and method for friction stir welding of high strength materials, and articles made therefrom

Abstract: An apparatus for friction stir welding, a weld tool for friction stir welding, and a method for making a weld tool for friction stir welding are presented. The weld tool comprises a tungsten-based refractory material. A method for manufacturing an article, where the method comprises providing the apparatus for friction stir welding, and the article produced by this method are also presented.

Aluminum alloy fin material for heat exchangers and heat exchanger including the fin material

Abstract: The present invention provides an aluminum alloy fin material for heat exchangers which has a thickness of 80 μm (0.08 mm) or less and excels in joinability to a tube material and in intergranular corrosion resistance. The aluminum alloy fin material is an aluminum alloy bare fin material or a brazing fin material which has a thickness of 80 μm or less and is incorporated into a heat exchanger made of an aluminum alloy manufactured by brazing through an Al—Si alloy filler metal. The structure of the core material before brazing is a fiber structure, and the crystal grain diameter of the structure after brazing is 50-250 μm. The Si concentration in the Si dissolution area on the surface of the fin material and at the center of the thickness of the fin material after brazing is preferably 0.8% or more and 0.7% or less, respectively.

Interfacial microstructure of partial transient liquid phase bonded Si3N4-to-Inconel 718 joints

Abstract: This work presents transmission electron microscopy (TEM) analysis of the interfacial microstructure in Si 3 N 4 -to-Inconel 718 joints with Ni interlayers produced by partial transient liquid phase bonding (PTLPB). Ti and Cu microfoils have been inserted between Si 3 N 4 and the Ni interlayer and joining has been performed at lower temperatures than previous PTLPBs of Si 3 N 4 with the same insert metals. The TEM work is focused on phase identification of the reaction layers between the Si 3 N 4 and the Ni interlayer. According to the TEM analysis, most of the Cu precipitates without reacting with Ti and Ni. Si diffused in the filler metal and thin reaction layer formed at the interface between Si 3 N 4 and the filler metal producing good bond-formation and hence, high interfacial strength. No interfacial fractures occurred after cooling from the bonding temperature of 900 °C, which supports the results observed in the TEM analysis. This work confirms that this joining process can produce a more heat resistant Si 3 N 4 -to-Inconel 718 joint than active brazing using Ag–Cu–Ti alloys.

Reaction layers and mechanisms for a Ti-activated braze on sapphire

Abstract: A study was conducted to understand the wetting phenomena observed in brazing of a Ti-containing active filler metal on sapphire substrates. The goal of the study was to understand the interfacial reactions that permit wetting of commercial Ag-Cu-Ti active filler metal to pure alumina, despite the lower thermodynamic stability of TiO2 relative to Al2O3. Based upon transmission electron microscope, electron microprobe, and Auger analyses, it is proposed that two coupled reactions and diffusion of reactants take place. The oxides TiO, Ti2O, and Cu3Ti3O were observed at the braze/ceramic interface. It is suggested that the complex oxide Cu3Ti3O grows at its interface with TiO, and the oxide TiO is produced by reaction of Ti and sapphire and is subsequently consumed at its interface with Cu3Ti3O. It is also suggested that Ti2O forms from Ti and TiO while cooling from the brazing cycle.

Applying of ultrasonic waves on brazing of alumina to copper using Zn-Al filler alloy

Abstract: Ultrasonic waves were applied during brazing of alumina to copper, The intensity of ultrasonic wave was 1 kW and 18 kHz and the aim of this work was to study the effect of the ultrasonic wave and brazing temperature on the properties of the braze joint between alumina and copper using Zn-Al alloys as filler metal.

Cold cracking studies on low alloy steel weldments: effect of filler metal composition

Abstract: The resistance to hydrogen cracking of Cr - Mo, Ni - Cr - Mo and Si - Mn steels which are employed in armoured vehicle construction was evaluated under implant test conditions. Austenitic stainless steel filler (AWS E312), which is reported to be resistant to hydrogen assisted cracking, was used to study the cracking tendency of all the three steels. Four other fillers, namely a nickel based filler (ENiCrFe-3), a low carbon, low alloy steel, a mild steel (AWS E6013) and a matching filler for Cr - Mo, were employed to evaluate their relative cracking tendency. Cr - Mo and Ni - Cr - Mo steels exhibited high cracking tendency while Si - Mn steel was resistant to cracking with the E312 filler. Cr - Mo steel was resistant to cracking with the nickel based filler, the low carbon, low alloy steel and the matching filler. The observed cracking tendency of the steels is linked to a susceptible interface/fusion boundary microstructure.

Yag laser induced arc filler wire composite welding method and welding equipment

Abstract: A combined welding method with a filler wire using both a YAG laser and an electric arc, and a combined welding device with a filler wire using both a YAG laser and an electric arc. The welding is performed by directing a laser focus of a YAG laser on base materials and for welding in the vicinity of the focus by a filler wire, connecting a power source for applying a voltage to the filler wire between the filler wire and the base materials for welding, irradiating a YAG laser on the base materials for welding in the connecting condition, whereby an arc is induced to the filler wire by a plume (plasma-activated gas and the metal vapor), and holding the plume generated by YAG laser inside and outside of a keyhole.

Aluminum alloy brazing fin material for heat exchanger

Abstract: PROBLEM TO BE SOLVED: To provide an aluminum alloy brazing fin material for an automobile heat exchanger using an aluminum tubular body in which a Zn covering layer is formed and subjected to no chromate treatment, whose formability is excellent, and in which the generation of pitting corrosion in the aluminum tubular body is suppressed in a severe corrosive environment, further, the corrosion resistance of a brazed part is excellent, and the departure of a fin from the aluminum tubular body can be prevented. SOLUTION: The aluminum alloy brazing fin material is obtained by cladding an Al-Si-based alloy brazing filler metal on both the sides of a core material. The core material is composed of an aluminum alloy comprising 0.8 to 2.5% Mn, 0.1 to 1.0% Si, 0.06 to 0.3% Fe and 0.8 to 4.0% Zn, and the balance Al with impurities. The brazing filler metal is composed of an aluminum alloy comprising 6 to 13% Si and 0.06 to 0.4% Cu, and the balance Al with impurities. The brazing filler metal is clad on both the sides of the core material, respectively, at a thickness of 3 to 20% to the whole thickness. COPYRIGHT: (C)2005,JPO&NCIPI

Gas Metal Arc Welding

Abstract: Gas metal arc welding (GMAW), sometimes referred to by its subtypes metal inert gas (MIG) welding or metal active gas (MAG) welding, is a semi-automatic or automatic arc welding process in which a continuous and consumable wire electrode and a shielding gas are fed through a welding gun. A constant voltage, direct current power source is most commonly used with GMAW, but constant current systems, as well as alternating current, can be used. There are four primary methods of metal transfer in GMAW, called globular, short-circuiting, spray, and pulsed-spray, each of which has distinct properties and corresponding advantages and limitations.

High-temperature brazing filler metal

Abstract: PROBLEM TO BE SOLVED: To provide a Pb-free high temperature brazing filler metal which has a melting temperature of ≥260°C, can be substituted with an Au based or Pb based alloy, has satisfactory wettability and reliability in bonding as well, and is suitable for use in the die bonding of a semiconductor device, the assembly of an electronic part or the like which are inexpensive. SOLUTION: The high temperature brazing filler metal has a composition consisting essentially of Bi, comprising, as a secondary metal element, either one kind of metal selected from, by mass, 1 to 12% Ag, 0.1 to 0.3% Cu and 2 to 8% Sb, and supplemented with 0.001 to 0.01% P. The brazing filler metal can comprise inevitable impurities, but, preferably, does not include Pb as inevitable impurities. COPYRIGHT: (C)2004,JPO

Industrial Brazing Practice

Abstract: The Fundamentals of Brazing Introduction Where Does Brazing Fit in Joining Technology? Reviewing the Brazing Process Brazing Terminology Designing for Brazing Joint Overlap Length Butt Joints Stress Distribution Tube-to-Tube Sleeve Joints Electrical Conductivity Pressure Tightness Surface Finish Optimum Joint Gaps Brazing Alloy Preplacement Preformed Wire Rings Preplaced Washers and Foils Slugs and Cropped Wire Pieces Brazing Alloy Pastes The Ten Golden Rules for Successful Joint Design Jigs and Fixtures Brazing Filler Materials and Fluxes The First Step The Temperature Ranges Widely Used for Brazing Class Al: Aluminum and Magnesium Brazing Filler Materials Class Ag: Silver Brazing Filler Metals Class CuP: Copper-Phosphorus Brazing Filler Metals Class CU: Copper Brazing Filler Materials Classes Ni: Nickel (and Cobalt) Brazing Filler Metals Unclassified Platinum-Group Metal Filler Alloys Classes PD and AU: The Noble-Metal Filler Alloys Brazing Fluxes Fuel Gases and Burners Flame Brazing Complexity Scale Heating and Flames Gases and Gas Mixtures Burner Design and Operational Parameters Pilotage Burner Efficiency Brazing with Flames Flame Brazing by Hand Automated Flame Brazing Summary Induction and Resistance Brazing Induction Heating Resistance Heating Furnace Brazing Furnace Atmospheres Other Types of Brazing Furnaces Vacuum Brazing Important Operational Procedures Brazing with Filler Material Pastes Aliphatic Compounds Aromatic Compounds Potential Drawbacks Paste Characteristics Using Pastes in Reducing Atmosphere Furnace Brazing Using Pastes in Vacuum Brazing Applications Brazing Aluminum Parent Metal Considerations Properties of Aluminum Joint Design Criteria Brazing Filler Materials Metallurgical Considerations Commonly Used Brazing Processes Recent Developments Brazing Commonly Used Materials Copper and Its Alloys Brazing Steels Tool Steels Stainless Steels Brazing Cast Iron Tungsten Carbide Question Time Is It Possible to Braze Ceramics? Can I Braze to a Plated Surface? Can Brass Be Successfully Brazed without Flux in a Reducing-Atmosphere Furnace? Is It Good Practice to Braze Tungsten Carbide Tips to Circular Saw Blades with a Brazing Alloy Conforming to ISO 17672: 2010 Types Cu 470 to Cu 773? Will There Be Problems with Brazed Joints That Are in Contact with Ammonia in Service? What Is MIG Brazing? What Is the CuproBraze(R) Process? The Methodology of Process Auditing Summary: The Fundamental Principles of the Brazing Process The Practical Application of the Process Audit The Process Efficiency Audit Appendix I: Selection Charts Appendix II: Filler Metal Comparison Tables Index

Nitrogen absorption by iron and stainless steels during CO2 laser welding

Abstract: Nitrogen absorption by iron, Fe-20Cr-10Ni alloy, and SUS329J1 duplex stainless steel during CO2 laser welding in an Ar-N2 gas mixture was investigated and compared with equilibrium data predicted on Sieverts’ law and data on absorption during arc and YAG laser welding. The nitrogen absorption during CO2 laser welding is lower than that during arc welding, but higher than that during YAG laser welding. Compared with arc welding, the lesser contact of monatomic nitrogen with the weld pool surface and the higher partial pressure of metal vapor in the keyhole may result in the lower nitrogen absorption during CO2 laser welding, while the very low density of monatomic nitrogen in the atmosphere during YAG laser welding due to the low-temperature plume may lead to the lower nitrogen absorption during YAG laser welding than during CO2 laser welding.

Numerical Modeling of the Transient Liquid-phase Diffusion Bonding Process of Al Using Cu Filler Metal

Abstract: A numerical modeling of dissolution and isothermal solidification during the transient liquid-phase (TLP) diffusion bonding process of Al using pure Cu filler metal based on a diffusion-controlled model was carried out. In the modeling, both the changes in volume accompanying interdiffusion between the base metal (All and the filler metal (Cu) and the solid-liquid transformation were taken into account by using variable grids. The effect of a load applied to the base metal was also examined by considering simple force balance among the surface and interface energies of the base metal and liquid formed in the bonding region. The early dissolution process simulated by the developed model agreed with the experimental results, and the predicted isothermal solidification time of a sample with an applied load also agreed with the experimental results.

Joining alumina to inconel 600 and UMCo-50 superalloys using an Sn10Ag4Ti active filler metal

Abstract: Alumina ceramics were brazed to Inconel 600 and UMCo-50 superalloys at 900 °C for 10 min using an Sn10Ag4Ti active filler metal. The brazing filler showed good wettability on alumina and superalloys. The flexural strengths were 69 and 57 MPa for alumina/Inconel 600 and alumina/UMCo-50 joints, respectively. In both cases, the brazed specimens fractured along the Sn10Ag4Ti/superalloy interfaces after four-point bending tests. Electron probe microanalysis (EPMA) elemental mapping revealed that the Ni of Inconel 600 and the Co of UMCo-50 dissolved into Sn10Ag4Ti filler metal, which serves to reinforce the weak Sn10Ag4Ti matrix.