Showing papers on "Filler metal published in 2005"

Pore formation during hybrid laser-tungsten inert gas arc welding of magnesium alloy AZ31B—mechanism and remedy

Abstract: One of the major concerns during high speed welding of magnesium alloys is the presence of porosity in the weld metal that can deteriorate mechanical properties. This study seeks to analyze the presence method and quantity of pore during hybrid laser-tungsten inert gas arc (TIG) welding of magnesium alloy AZ31B by radiography, optical microscopy and electron probe microanalysis (EMPA). At the same time, it identifies both the mechanism of pore formation and a remedy for this problem. The experimental results indicate that lacking of shielding gas for laser beam is the dominant cause of macroporosity formation during the hybrid of laser-TIG welding of magnesium Alloys AZ31B plate, and hydrogen is not main cause to form large pores. A favorable weld without porosity can be obtained by appending lateral shielding gas for laser beam.

Evaluation of TIG flux welding on the characteristics of stainless steel

Abstract: The aim of the present study was to investigate the effect of specific oxide fluxes on the surface appearance, weld morphology, retained δ ferrite content, hot cracking susceptibility, angular distortion and mechanical properties obtained with the tungsten inert gas (TIG) process applied to the welding of 5 mm thick austenitic stainless steel plates. An autogenous gas tungsten arc welding process was applied to stainless steels through a thin layer of activating flux to produce a bead on plate welded joint. The MnO2 and ZnO fluxes used were packed in powdered form. The experimental results indicated that the 80% MnO2–20% ZnO mixture can give full penetration and also a satisfactory surface appearance for type 304 stainless steel TIG flux welds. TIG welding with MnO2 and/or ZnO can increase the measured ferrite number in welds, and tends to reduce hot cracking susceptibility in as welded structures. It was also found that TIG flux welding can significantly reduce the angular distortion of stainless...

Diode laser brazing of aluminium alloy to steels with aluminium filler metal

Abstract: Diode laser brazing of aluminium alloy (A5052) to interstitial free steel (IF steel) or type 304 stainless steel (SUS304) was conducted using aluminium filler metal (BA4047) with Nocolock flux. The processing parameters of laser power, wire feed rate and travel speed were varied. The strength of lap joints of A5052 on steels was evaluated by tensile shear test. The joint strength of A5052/steels was increased with increasing laser power and reached the maximum strength, more than approximately 80% of the A5052 base metal strength, at a laser power of 1300 W. Voids and incomplete penetration of filler metal were observed at the A5052/braze layer interface when the laser power was below 1100 W. The Fe–Al intermetallic compounds were formed at the steel/braze layer interfaces and grew drastically when the laser power exceeded 1300 W. Superior brazability of A5052/steels was found at brazing conditions corresponding to a temperature of filler metal droplet of 1050–1250 K.

Influence of welding processes on microstructure and mechanical properties of dissimilar austenitic-ferritic stainless steel welds

Abstract: Dissimilar metal welding of austenitic (AISI 304)-ferritic (AISI 430) stainless steel has been taken up to understand the influence of the welding process on microstructure and mechanical properties. Fusion welding processes, namely, gas tungsten arc welding (GTAW), electron beam welding (EBW), and friction welding, have been employed. The GTAW and EBW processes were selected to understand the heat input effects, while friction welding was included to compare fusion and solid-state welding processes. The material used for fusion welding studies is 20-mm-thick, hot-rolled, and annealed plate. Rods of 18 mm diameter machined from the same plate material were used for friction welding studies. In GTAW, ER 430 filler material was employed for dissimilar metal combination, while other welds are autogenous. Gas tungsten arc welds consisted of coarse columnar grains. In electron beam welds, the microstructure consisted of predominantely equiaxed grains on the austenitic stainless steel side, while colum...

Residual welding stresses in laser beam and tungsten inert gas weldments of titanium alloy

Abstract: The residual welding stresses in laser beam (LB) and tungsten inert gas (TIG) weldments of a titanium alloy in thin plate form were investigated experimentally in the present work. A hole drilling technique was used to measure the residual stresses in the weldments. The effects of the welding method and post-weld heat treatment (PWHT) on the residual stresses were analysed. The results show that (i) the residual stress distribution in the LB welded joints is similar to that obtained for traditional fusion welding processes, although the distribution zone is much narrower in LB welding, (ii) the residual stress in the heat affected zone for LB welding is about 100 MPa lower than that for TIG welding, and (iii) PWHT in vacuum greatly relieves the welding residual stress.

Prediction of welding distortions and residual stresses in a pipe–flange joint using the finite element technique

Abstract: This paper presents a comparative study of three- and two-dimensional axisymmetric finite element (FE) analyses of a welded pipe–flange joint for residual stresses and deformations in order to identify their merits or demerits. Sequentially coupled thermal stress analysis is performed to simulate single pass metal inert gas welding. Butt weld geometry with a single 'V' for a 100 mm nominal diameter pipe and same sized weld neck type ANSI class #300 flange is used. The heat input is modelled by using the Goldak double ellipsoidal heat source model. Temperature dependent material properties are used and deposition of filler metal is obtained by element birth and death feature. Both thermal and structural FE models are validated with experimental measurements. Residual stresses predicted by two-dimensional model are generally on the higher side and hence more conservative. However, we conclude that the three-dimensional FE model is preferable for the prediction of flange face distortion since it is a vital parameter for flange joint performance.

Laser Hybrid Welding Method and Laser Hybrid Welding Torch Using a Zinc and/or Carbon and/or Aluminum-Containing Rod

Abstract: The invention relates to a method for welding coated sheet metal (3) by way of a laser hybrid welding method, whereby at least one laser method and one shielded arc-welding method are carried out, and a weld metal (12) is supplied to the weld by way of the shielded arc-welding method. The invention also relates to a laser hybrid welding torch for welding coated sheet metal (3), which comprises at least one laser (13) and at least one shielded arc unit (5) and a rod feeding device (11) for a welding rod (12). The aim of the invention is to provide a method or a device of the aforementioned kind which allows for reducing or completely avoiding inclusions such as are e.g. caused by the evaporation of the coating of the metal sheet (3). For this purpose, a clamping device (6) is used for positioning the coated metal sheet (3) without substantial gaps between the individual sheets. A material having a zinc and/or carbon and/or aluminum content is used as the weld metal or welding rod (12).

Microstructure and strength of brazed joints of Ti3Al-base alloy with TiZrNiCu filler metal

Abstract: Brazing of Ti 3 Al alloys with the filler metal TiZrNiCu was carried out at 1173–1373 K for 60–1200 s. The relationship of brazing parameters and shear strength of the joints was discussed and the optimum brazing parameters were obtained. When products are brazed, the optimum brazing parameters are as follows: brazing temperature is 1273–1323 K, brazing time is 250–300 s. The maximum shear strength of the joint is 250–260 MPa. Four kinds of reaction products were observed to have formed during the brazing of Ti 3 Al alloys with the filler metal TiZrNiCu, namely Ti 2 Ni + TiCu intermetallic compounds formed close to the Ti 3 Al alloy. TiNi 2 Cu intermetallic compounds layer formed between Ti 2 Ni + TiCu intermetallic compounds and the filler metal and a Ti[s,s] (here s,s means super saturation) solid solution formed with the dispersed TiNi 2 Cu in the middle of the joint. The interfacial structure of brazed Ti 3 Al alloys joints with the filler metal TiZrNiCu is Ti 3 Al/Ti 2 Ni + TiCu/TiNi 2 Cu/Ti[s,s] solid solution + TiNi 2 Cu/TiNi 2 Cu/TiCu + Ti 2 Ni/Ti 3 Al and this structure will not change with brazing time once it forms. The formation of over many intermetallic compounds Ti 2 Ni + TiCu + TiNi 2 Cu results in embrittlement of the joint and poor joint properties. The thickness of Ti 2 Ni + TiCu + TiNi 2 Cu intermetallic compounds increases with brazing time according to a parabolic law. The activation energy Q and the growth velocity K 0 of the reaction layer Ti 2 Ni + TiCu + TiNi 2 Cu in the brazed joints of Ti 3 Al alloys with the filler metal TiZrNiCu are 261 kJ/mol and 0.0434 mm 2 /s, respectively and the growth formula was y 2 = 0.0434 exp(−31392.83/ T ) t . Careful control of the growth of the reaction layer Ti 2 Ni + TiCu + TiNi 2 Cu can influence the final joint strength.

The Role of Binder Content on Microstructure and Properties of a Cu-base Active Brazing Filler Metal for Diamond and cBN

Abstract: Melting experiments of Cu-Sn-Ti-Zr filler metal powder containing cellulose nitrate and graphite, respectively, resulted in the formation of nanosized TiC particles in both Cu-rich phase and CuSn 3 Ti 5 intermetallic regions of the alloy (see figure). The variation of the binder type and content allows to tailor the properties of the filler metals in terms of erosion resistance, decisive for a new generation of superabrasive tools.

Resistance welding method of different kinds of materials, and resistance welding member of aluminum alloy material and different kind of material

Abstract: The resistance welding method of different kinds of materials is the method for welding an iron material and an aluminum alloy material, and comprises the steps of: performing in advance a coating treatment at least to a portion of the aluminum alloy material, where resistance welding is performed, with any of iron and iron-base alloy and forming a surface layer; and performing resistance welding of the iron material and the aluminum alloy material through the surface layer, and the resistance welding may be any of spot welding and projection welding.

Probing liquation cracking and solidification through modeling of momentum, heat, and solute transport during welding of aluminum alloys

Abstract: A transport phenomena-based mathematical model is developed to understand liquation cracking in weldments during fusion welding. Equations of conservation of mass, momentum, heat, and solute transport are numerically solved considering nonequilibrium solidification and filler metal addition to determine the solid and liquid phase fractions in the solidifying region and the solute distribution in the weld pool. An effective partition coefficient that considers the local interface velocity and the undercooling is used to simulate solidification during welding. The calculations show that convection plays a dominant role in the solute transport inside the weld pool. The predicted weld-metal solute content agreed well with the independent experimental observations. The liquation cracking susceptibility in Al–Cu alloy weldments could be reliably predicted by the model based on the computed solidifying weld-metal composition and solid fraction considering nonequilibrium solidification.

Strength and Microstructure of Silicon Nitride Ceramics Brazed with Nickel‐Chromium‐Silicon Alloys

Abstract: Joining of sintered Si{sub 3}N{sub 4} was performed using a high-temperature brazing technique. Ni-based brazing alloys having the same Ni:Cr ratio as AWS BNi-5 (Ni{center_dot}18Cr{center_dot}19Si (at.%)) but different Si content were used as the brazing filler metals. Joining experiments were performed at 1,220 C under a N{sub 2} partial pressure of 15 Pa for different times between 5 to 15 min. The highest room-temperature four-point bend strength of the joints was 115 MPa, whereas 220 MPa was achieved when the joints were tested at 900 C. The high strength of the experimental joints was attributed to the reduction in residual stresses and formation of a CrN reaction layer at the ceramic/filler metal interface.

Nitrogen desorption by high-nitrogen steel weld metal during CO2 laser welding

Abstract: Nitrogen desorption by high-nitrogen steels (HNSs) containing 0.32 and 0.53 pct nitrogen during CO2 laser welding in an Ar-N2 gas mixture was investigated and the obtained data were compared with those for arc welding and at the equilibrium state predicted by Sieverts’ Law. Although the nitrogen content in the weld metal during CO2 laser welding was lower than that in the as-received base material in all conditions, the nitrogen desorption was larger in the top part of the weld metal than in the keyhole region. The nitrogen desorption in the Ar atmosphere was less during CO2 laser welding than during arc welding. With the increase in nitrogen partial pressure, the nitrogen content in the weld metal sharply increased during arc welding, but only slightly increased during CO2 laser welding. The nitrogen absorption and desorption of the HNS weld metal were much smaller during CO2 laser welding than during arc welding.

Vacuum-furnace brazing of C103 and Ti–6Al–4V with Ti–15Cu–15Ni filler-metal

Abstract: C103 and Ti–6Al–4V alloys joined by vacuum-furnace brazing using Ti–15Cu–15Ni (wt%) commercial filler-metal was investigated This study examines how brazing conditions affect the microstructural evolution and shear strength of the C103/TiCuNi/Ti–6Al–4V joint According to the microstructural observations, all the characteristic structures of the joint interface can be classified into seven categories, based on their morphology and chemical composition The microstructural morphology of each characteristic zone depends on the brazing time and the brazing temperature Excessive increasing the brazing time and the brazing temperature form the coarse acicular Widmanstatten structure in front of Ti–6Al–4V parent-metal and cause grain growth of Ti–6Al–4V alloy However, if the brazing time is too short or the brazing temperature is too low, the continuous intermetallic-layer consisting of intermetallic compounds, such as Ti 2 (Cu, Ni) and Ti 2 (Ni, Cu), will remain in the brazed joints after brazing Additionally, during brazing, the diffusion of molten liquid filler-metal and the dilution of parent-metals cause the composition of the filler-metal to deviate from the Ti–Cu–Ni eutectic into the hypoeutectic or hypereutectoid Therefore, the joint interface is anticipated to be comprised mostly of eutectic and/or eutectoid structures The fine hypoeutectic and hypereutectoid structures consisting of α-Ti, Ti 2 (Ni, Cu) and Ti 2 (Cu, Ni) are observed in the joint interface brazed at 960 °C for 15 min The maximum shear strength reaches 354 MPa under this brazing condition Further increasing the brazing time and/or raising the brazing temperature cause excessive growth of the Widmanstatten structure and the grain of Ti–6Al–4V alloy, which significantly deteriorate the shear strength of joint The high temperature shear strength of the C103/TiCuNi/Ti–6Al–4V joint was investigated to evaluate its limit service temperature Moreover, the overlap-length and the joint clearance investigations are also conducted to realize the relations between different brazing conditions and the joint performance

Methods for extending the life of alloy steel welded joints by elimination and reduction of the haz

Abstract: In one embodiment, the present invention provides a method for welding together two metal pieces, comprising buttering a surface of a first metal piece with a first nickel-based filler metal at a thickness sufficient to isolate a heat-affected zone in the first metal piece from subsequent welding; heat-treating at least the heat-affected zone in the first metal piece; buttering a surface of a second metal piece with a second nickel-based filler metal having the same composition as the first nickel-based filler metal and at a thickness sufficient to isolate a heat-affected zone in the second metal piece from subsequent welding; heat-treating at least the heat-affected zone in the second metal piece; and welding the heat-treated first buttered surface to the heat-treated second buttered surface with a third nickel-based filler metal having the same composition as the first and second nickel-based filler metals.

Study on filler metal (Ni-Fe-C) during GTAW of WC-30Co to 45″ carbon steel

Abstract: In this study, WC-30Co cemented carbide is welded to carbon steel by the gas tungsten arc welding (GTAW) using Ni-Fe filler metal and Ni-Fe-C filler metal The butt joints manifest more embrittling η-phase carbides with Ni-Fe filler metal, while less even no η-phase carbides with Ni-Fe-C filler metal The η-phase carbides morphology and formative factors were further discussed using Backscattered Electron Imaging (BEI) method; Electronic probe microanalysis (EPMA) is used to determine the distribution of elements Ni, Fe, C, W and Co across the HAZ (Heat Affected Zone) near WC-30Co/welded-seam interface The hardness profile is determined using micro-hardness measurements and bend strength value of butt joint with different filler metal is tested by four-point bend strength test The hardness profile and bend strength value agree with the information obtained from microstructure analysis, BEI analysis and X-rays phase analysis very well The results show: (1) butt joint of WC-30Co/carbon steel can be obtained using GTA with Ni-Fe-C filler metal; (2) the addition of carbon content to Ni-Fe filler metal leads to less even none η-phase multi-carbides strongly, and mechanical property of butt joint can be improved

Interfacial Reactions between Sapphire and Silver—Copper—Titanium Thin Film Filler Metal

Abstract: Wetting and brazing studies of sputtering-deposited, submicrometer thin film filler metal in an Ag—Cu—Ti/Al2O3 system were performed. The interfacial reaction layer between the filler metal and Al2O3 was investigated. It is possible to make a brazing joint even with a reaction layer of less than 100 nm thickness. Different types of interfacial reaction layers were observed when the Ti content in the filler metal was varied. The Cu—Ti—O system compounds were observed in the samples with high wetting capabilities, but not in the sample with low wetting characteristics. It was found that these compounds are substances that promote effective brazing.

New Insight into the Mechanism of Ductility-Dip Cracking in Ni-base Weld Metals

Abstract: The ductility dip cracking resistance of Ni-base Filler Metal 52 (AWS A5.14, ERNiCrFe-7; ISO SNi6052, 59 % Ni, 29 % Cr, 9 % Fe, 1 % Mn, 1 % Al) and Filler Metal 82 (AWS A5.14, ERNiCr-3; ISO SNi6082, 72 % Ni, 20 % Cr, 1 % Fe, 3 % Mn, 3 % Nb) has been extensively evaluated using the recently developed strain-to-fracture test in conjunction with microstructural characterization using electron microscopy. This paper provides new insight into the creep-like, grain boundary sliding mechanism that leads to elevated temperature intergranular cracking in these weld deposits. The effect of precipitation on grain boundary tortuosity and sliding, and its influence on ductility-dip cracking resistance is discussed in the context of current theories of high temperature creep. Finally, the effect of impurity and interstitial elements on ductility-dip cracking is discussed.

Characteristics of High Speed Welding between 6063 and S45C by Means of Friction Stirring-Study on Welding in Dissimilar Metals by Means of Friction Stirring (1st Report)-

Abstract: Friction stir welding (FSW) has become an important joining process of aluminum alloys in various industries. Conventional FSW process, however, is difficult to apply to the welding in dissimilar metals. In our series of research, the welding between aluminum alloy and steel has achieved by means of friction stirring. This is a promising way to realize a high performance joint in dissimilar metals. In the present study, the weldability between 6063 and S45C by means of friction stirring was investigated. By optimizing the welding conditions, such as a tool configuration and a rotating speed, higher welding speed more than 1000 mm/min was achieved. The mechanical properties of the weld joints fabricated were evaluated with the normal tensile test and hardness test. The specimens were fractured in the portion of the lowest hardness area in aluminum alloy. In the microstructure observation with SEM, thick intermetallic compound layer on the interface region was not detected.

Development of flux and filler metal for brazing magnesium alloy AZ31B

Abstract: This study was carried out to develop new flux and filler metal to braze magnesium Alloy AZ31B more easily at a lower temperature. A flux was successfully developed consisting of CaCl 2 , LiCI, and NaCI with Ca and Li ions, which made the magnesium alloy surface active at around 450°C. Additionally, brazing filler metals with a melting temperature below 480°C were successfully developed. Magnesium and indium were the main components , along with 0.2 to 6.4 wt-% zinc to lower the melting temperature. With a small amount of zinc, the flux and filler metals achieved a joint with a high strength equivalent to the base metal. As the amount of zinc increased, the joint strength decreased.

Ni BRAZING FILLER METAL ALLOY

Abstract: PROBLEM TO BE SOLVED: To provide an Ni brazing filler metal alloy having satisfactory corrosion resistance and relatively high strength, and having a liquidus temperature low in a degree to braze stainless steel and copper SOLUTION: The Ni brazing filler metal has a composition comprising, by weight, 5 to 16% Cr, 2 to 9% P, 1 to 6% Si and 05 to 25% B, and in which the total weight of P, Si and B lies in the range of 8 to 11%, and the balance Ni of 73 to 87% with inevitable impurities COPYRIGHT: (C)2007,JPO&INPIT

Finding the Optimum Parameters for Ultrasonic Welding of Aluminum Alloys

Abstract: The ultrasonic welding method has been expected to replace other welding and brazing processes, and this paper is concerned with an experimental study on the ultrasonic welding of an aluminum alloy onto other three aluminum alloys. In this study the relation between energy density and welding pressure in welding certain types of aluminum alloys was clarified. For example, the ultrasonic welding of an aluminum alloy can be accomplished under the condition E=K1Pn1