Weld Filler Research Articles

Microstructure and mechanical properties of carbon nanotubes/AZ31 magnesium composite gas tungsten arc welding filler rods fabricated by powder metallurgy

In the present study, carbon nanotubes/AZ31 magnesium composite filler rods of gas tungsten arc (GTA) welding were fabricated for the first time by powder metallurgy. After welding, the effect of carbon nanotubes (CNTs) on the microstructure and mechanical properties of nanocomposite welds was evaluated. By applying ball milling, CNTs were uniformly distributed in the filler rods. Consequently, the nanocomposite welds produced by these filler rods had a uniform distribution of CNTs in their compositions. Tensile tests revealed that the tensile strength of 1wt% CNTs-reinforced weld was increased by 65% compared with unreinforced weld. Therefore, it can be concluded that CNTs can be good reinforcement candidates in GTA welding of magnesium and its alloys.

ALCOTEC WELD FILLER WIRE 5356

Abstract Alcotec weld filler wire 5356 is a non-heat-treatable aluminum welding wire whose principal alloying elements are magnesium, manganese, and chromium. It is similar to the European wire AlMg5Cr(A). This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on corrosion resistance as well as forming and joining. Filing Code: Al-445. Producer or source: AlcoTec Wire Corporation.

Structure-property relationships of common aluminum weld alloys utilized as feedstock for GMAW-based 3-D metal printing

The relationship between microstructure and properties is not widely assessed in parts produced by additive manufacturing, particularly for aluminum. These relationships can be used by engineers to develop new materials, additive processes, and additively manufactured parts for a variety of applications. Thus, the tensile, compressive, and microstructural properties of common aluminum weld filler alloys (ER1100, ER4043, ER4943, ER4047, and ER5356) were evaluated following gas metal arc weld (GMAW)-based metal 3-D printing to identify optimal alloy systems for this type of additive manufacturing. The porosities in all test specimens were found to be less than 2%, with interdendritic shrinkage in 4000 series alloys vs. intergranular shrinkage in 5356. The 4000 series alloys performed better than 1100 and 5356 with respect to printed bead width, porosity, strength, and defect sensitivity. In comparison to standard wrought and weld alloys, the 3-D printed specimens exhibited similar or superior mechanical properties with only minor exceptions. Long print times allow for stress relieving and annealing that improved the print properties of the 4000 series and 5356 alloys. Overall the GMAW-based 3-D parts printed from aluminum alloys exhibited similar mechanical properties to those fabricated using more conventional processing techniques.

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

Novel “ECO Mg” alloys, i.e., CaO-added Mg alloys, which exhibit oxidation resistance during melting and casting processes, even without the use of beryllium or toxic protection gases such as SF6, have recently been introduced. Research on ECO Mg alloys is still continuing, and their application as welding filler metals was investigated in this study. Mechanical and metallurgical aspects of the weldments were analysed after welding, and welding behaviours such as fume generation and droplet transfer were observed during welding. The tensile strength of welds was slightly increased by adding CaO to the filler metal, which resulted from the decreased grain size in the weld metal. When welding Mg alloys, fumes have been unavoidable so far because of the low boiling temperature of Mg. Fume reduction was successfully demonstrated with a wire composed of the novel ECO Mg filler. In addition, stable droplet transfer was observed and spatter suppression could be expected by using CaO-added Mg filler wire.

Relation between Friction Stir Spot Welding Parameters and Mechanical Properties of High Density Polyethylene/Glass Spheres Polymer Composites

In the present study, we attempt to use powder of glass spheres filler and reinforce material in HDPE to produce composite structure and then evaluate its mechanical properties to study the effect of welding parameters and filler content on mechanical properties of HDPE. The effect of welding parameters (tool rotational speed, the plunge depth and the dwell time) on friction stir spot welding properties of high density polyethylene/glass spheres (hollow) polymer composites sheets was studied.

Primerjava mikrostrukture toplotno vplivanega področja varjenega in simuliranih vzorcev

The high-strength steel grade S690QL and a filler welding wire Mn3Ni1CrMo were the materials chosen for welding a V-shaped butt weld. In order to prevent the weld’s cold cracking, a multi-pass welding technique was applied. A metallographic investigation revealed microstructure variations in different areas of the weld’s heat-affected zone. A reverse-engineering approach was used to test a dilatometer’s capabilities to simulate different HAZ microstructures. Hollow steel-cylinder specimens were subjected to several weld thermal cycles in order to generate similar microstructures as in the real weld’s HAZ. The microstructures of the as-welded and simulated heat-affected zone specimens were investigated. Good agreement was found between the dilatometer-simulated HAZ microstructures and those in a real HAZ weld.

Technology Update: Biocide Treatment Program Reduces Premature Coiled Tubing Failures

Technology Update Premature coiled tubing (CT) failures have occurred in the United States, in areas such as the Eagle Ford and Haynesville formations, and the Permian Basin. In Canada, these failures once were not considered as prevalent. However, a presentation at the 2015 SPE/ICoTA conference in The Woodlands, Texas, changed that perception. A paper presented there detailed how a major Canadian CT service provider experienced a series of CT string failures while performing bridge plug millout operations in the Montney formation in northeastern British Columbia (Edillon et al., 2015). With each trip in or out of the wellbore, CT strings incur fatigue that can be estimated using simulation software based on the CT outside diameter (OD), material grade, and operating conditions. CT strings can fail for a variety of reasons, including external mechanical damage, corrosion, and excessive diametrical growth. Premature failure results not only in operational delays and the associated costs, but critical safety risks for onsite personnel. For these reasons, a study was undertaken to determine the root cause of the CT string failures in the Montney. The results showed that microbial influenced corrosion (MIC) was a contributing factor. This led the CT service provider to instigate laboratory and field studies to create a biocide treatment program. The program has successfully mitigated further CT string failures in the Montney and has now been applied to CT programs in the Eagle Ford formation. CT String Analysis Seven failures of 60.3-mm (2.375-in.) CT strings supplied by multiple manufacturers were experienced over 2½ months. The strings failed in the range of 18% to 49% fatigue—well below their predicted 80% fatigue life. Preliminary analysis of the failure points revealed pinholes and internal corrosion in the base material and at the bias weld. The filler material used in bias welds has different mechanical properties than the base pipe material, making it weaker and more fatigue-prone. To determine the failure mechanism, CT strings from four of the seven units were further analyzed by the manufacturers. In all four cases, internal corrosion pitting was observed. Comprehensive analysis on one string, including scanning electron microscopy, energy-dispersive X-ray spectroscopy, and metallography, was performed by the manufacturer and the University of Calgary. The analysis revealed that failure occurred at the bias weld and indicated microcorrosion pitting and transverse cracking in the weld filler material (Fig. 1). The corrosion morphology (rounded shape with light green corrosion debris) and the presence of sulfur in the corrosion product provided indirect evidence of MIC.

Process Optimization of Dual-Laser Beam Welding of Advanced Al-Li Alloys Through Hot Cracking Susceptibility Modeling

Abstract Laser welding of advanced Al-Li alloys has been developed to meet the increasing demand for light-weight and high-strength aerospace structures. However, welding of high-strength Al-Li alloys can be problematic due to the tendency for hot cracking. Finding suitable welding parameters and filler material for this combination currently requires extensive and costly trial and error experimentation. The present work describes a novel coupled model to predict hot crack susceptibility (HCS) in Al-Li welds. Such a model can be used to shortcut the weld development process. The coupled model combines finite element process simulation with a two-level HCS model. The finite element process model predicts thermal field data for the subsequent HCS hot cracking prediction. The model can be used to predict the influences of filler wire composition and welding parameters on HCS. The modeling results have been validated by comparing predictions with results from fully instrumented laser welds performed under a range of process parameters and analyzed using high-resolution X-ray tomography to identify weld defects. It is shown that the model is capable of accurately predicting the thermal field around the weld and the trend of HCS as a function of process parameters.

Laser beam welding of magnesium to coated high-strength steel 22MnB5

Magnesium alloy AZ31 was laser-welded to AlSi10Fe3-coated high-strength steel 22MnB5. The surface of the 22MnB5 steel sheet was treated by sandblasting before welding. Laser welding of magnesium with steel was found to be a welding-brazing process, due to the large difference in the melting temperatures of steel and magnesium. The liquid magnesium was wetted on the solid steel surface, which thus was a brazing process on the steel side. AZ61 magnesium welding filler was used to improve adhesion of the liquid magnesium to the steel surface. Furthermore, the suitability of using a flux was determined. Welded steel/magnesium joints with a high tensile strength of 2680–3090 N (178–213 MPa) were produced using a flux and inductive preheating of the conditioned steel surface. Under tensile loading, the welded joints did not fail at the steel/magnesium interface, but in the AZ61 magnesium welding filler. Metallurgical bonding at the magnesium/steel interface was attributed to the formation of a thin Al-Fe-rich layer, which is due to the alloyed aluminum (6 mass%) in the magnesium welding filler.

Analysis of Residual Stresses and Angular Distortion in Stiffened Cylindrical Shell Fillet Welds Using Finite Element Method

In this paper, a two-dimensional method is developed to simulate the fillet welds in a stiffened cylindrical shell, using finite element method. The stiffener material is aluminum 2519. The thermo-elasto-plastic analysis is used to analyze the thermo-mechanical behavior. Due to the high heat flux rate of the welding process, two uncouple thermal and mechanical analysis are carried out instead of performing a single couple thermo-mechanical simulation. In order to investigate the effects of the welding procedures, two different welding techniques are examined. The resulted residual stresses and distortions due to different welding procedures are obtained. Furthermore, this study employed the technique of element birth and death to simulate the weld filler variation with time in fillet welds. The obtained results are in good agreement with the published experimental and three-dimensional numerical simulation results. Therefore, the proposed 2D modeling technique can effectively give the corresponding results of 3D models. Furthermore, by inspection of the obtained residual hoop and transverse stresses and angular distortions, proper welding procedure is suggested.

Effect of the welding process and filler material on the fatigue behavior of 960 MPa structural steel at a butt joint configuration

Ultrahigh-strength steels are being used more and more frequently in the engineering industry. Normally, the welding of these steels is more demanding. The welding requires a controlled heating and cooling rate. In this study, the S-N curves were determined for the laser, the laser-gas metal arc hybrid (Laser-GMA hybrid welding, LHW) and the gas metal arc welding (GMAW) welded joints according to the recommendations of the International Institute of Welding (IIW) by using a constant amplitude loading and a stress ratio of R = 0.1. The frequency of loading varied between 4 and 10 Hz. The tested material was direct quenched steel with a yield strength of 960MPa and a thickness of 6 mm. The total amount of tested specimens was 51. The fatigue test results have proven to be close to the IIW recommendations and the differences between various welding processes were minor. Instead of welding process or filler material, the main factor influencing the fatigue behavior was the geometry of the weld. Consequently, the proper welding parameters should be applied in every welding process in order to achieve a smooth joint geometry and, thus, a high fatigue resistance.

Improved weld strength of vibration welded polyoxymethylene/multiwalled carbon nanotubes hybrid nanocomposites

In this study, carbon nanotubes reinforced polyoxymethylene with different filler loadings was joined by using linear vibration welding technique. The tensile properties of vibration welded polyoxymethylene nanocomposites with different carbon nanotube contents were studied as functions of filler loading and weld pressure. The results showed that the addition of carbon nanotubes into polyoxymethylene slightly improved the matrix tensile strength and pronounced decreased the ductility of pure polyoxymethylene. Interestingly, the weld strength of the nanocomposites was also higher than the polymer matrix strength even at high weld pressure of 2 MPa. Possible reasons for this high weld strength are discussed based on the morphological investigations. POLYM. ENG. SCI., 2016. © 2016 Society of Plastics Engineers

Effect of transverse mechanical arc oscillation on hot cracking (solidification & liquation) and weld metal properties of AA2014 T6 TIG welds

Effect of Transverse Mechanical Arc Oscillation on solidification and liquation cracking in autogenous and filler metals (standard AA4043 and non-standard AA1100 fillers) full penetration heat treatable AA2014 T6 aluminium alloy has been investigated. Both, linear and circular TIG welds were made using specially designed welding setup using Mechanical Arc Oscillation. Arc oscillation was carried out using range of oscillation parameters (amplitude: 0.9–2.0 mm and frequency: 0.28–1.5 Hz). Microstructure and mechanical tests studies were carried out to determine the extent of hot cracking, changes in the microstructure in weld fusion zone and adjacent, partially melted zone and weld mechanical properties respectively. Reduction/elimination of both solidification and liquation cracking due to arc Transverse Mechanical Arc Oscillation in autogenous and filler metal linear and circular TIG welds of AA2014 T6 alloy was significant. Optimum oscillation parameters: amplitude (0.9 mm) and frequency (0.48 Hz), significantly assisted to reduce/eliminate cracking in the fusion zone and adjacent partially melted zone. Interestingly, in these welds, fusion zone grain size was minimum, 12 μm as compared to 21.9 μm in without arc oscillation. Solidification cracking tendency had a non-monotonic dependence while liquation cracking showed monotonic dependence on the combination of arc oscillation parameters with AA1100 filler welds. AA4043 filler welds produced noticeable improvements in mechanical properties. Increments upto 16.6% in YS, 5.6% UTS, 34% ductility, and 17% joint efficiency.

An Investigation of the Microstructure of an Intermetallic Layer in Welding Aluminum Alloys to Steel by MIG Process.

Butt joints of A5052 aluminum alloy and SS400 steel, with a new type of chamfered edge, are welded by means of metal inert gas welding and ER4043 Al-Si filler metal. The microhardness and microstructure of the joint are investigated. An intermetallic layer is found on the surface of the welding seam and SS400 steel sheet. The hardness of the intermetallic layer is examined using the Vickers hardness test. The average hardness values at the Intermetallic (IMC) layer zone and without the IMC layer zone were higher than that of the welding wire ER4043. The tensile strength test showed a fracture at the intermetallic layer when the tensile strength is 225.9 MPa. The tensile value test indicated the average of welds was equivalent to the 85% tensile strength of the A5052 aluminum alloy. The thickness of the intermetallic layers is non-uniform at different positions with the ranges from 1.95 to 5 μm. The quality of the butt joint is better if the intermetallic layer is minimized. The Si crystals which appeared at the welding seam, indicating that this element participated actively during the welding process, also contributed to the IMC layer’s formation.

Removal of oxides and brittle coating constituents at the surface of coated hot-forming 22MnB5 steel for a laser welding process with aluminum alloys

Abstract The surface of a press-hardened steel 22MnB5 coated with Al-base (AlSi10Fe3) and Zn-base (ZnNi10) was conditioned by a pulse laser and by sandblasting to remove undesirable oxides and brittle phases. Oxides formed on coating surfaces counteract the wettability of welding filler during a welding or brazing process. Furthermore, welding and brazing joints of 22MnB5 coated with aluminum alloys failed along the brittle intermetallic phases in the coating under a low mechanical load. Treated 22MnB5 surfaces were analyzed microscopically, and the phase compositions were investigated by synchrotron diffraction measurements. It was found that brittle phases could be locally removed by laser ablation; however, high laser energies led to remelting and oxidation of the coating surface. In contrast, sandblasting homogenously removed oxides and brittle intermetallic phases. Surface-treated 22MnB5 steel sheets were joined to AA6016 aluminum sheets by laser welding, and the strength of the weldment was determined by tensile tests. The measured mechanical strength of the aluminum/steel joints was 210–230 MPa. Failure of the weldments under tensile loading occurred within the aluminum sheet, away from the steel surface/welding filler interface if brittle coating components and oxides were removed homogenously.

Impact of the hard facing technology and the filler metal on tribological characteristics of the hard faced forging dies

Subject review The forging dies are parts, which are operating at elevated temperatures, while simultaneously subjected to variable loads that can be compressive even impact and shear. Impact of the hard facing technology is very strong since varying of the hard facing parameters directly affects the output characteristics of the hard faced layers. The criterion for estimating that impact was based on results of performed tribological investigations. The tribological parameters that were monitored were the friction coefficient, the wear scar/trace width and the wear area of the hard faced layers, with the two different types of lubricants. Hard facing technology implied selection of the welding process, filler metals, preheating temperatures and other parameters of the hard facing process. The influence of the proposed hard facing technology was determined by monitoring hardness, microstructure and wear resistance of the executed joints after the hard facing and after tempering. The objective of this work was to establish the correlation between the selected hard facing technology, filler metals and applied heat treatment on mechanical and tribological characteristics of the executed hard faced layers.

Study of the corrosion behavior of magnesium alloy weldings in NaCl solutions by gravimetric tests

In this article, the corrosion behavior of commercial AZ31 welded plates in aqueous chloride media was investigated by means of gravimetric techniques and Neutral Salt Spray tests (NSS). The AZ31 samples tested were welded using Gas Tugsten Arc Welding (GTAW) and different filler materials. Material microstructures were investigated by optical microscopy to stablish the influence of those microstructures in the corrosion behavior. Gravimetric and NSS tests indicate that the use of more noble filler alloys for the sample welding, preventing the reduction of aluminum content in weld beads, does not imply a better corrosion behavior.

Study of tensile strength of aluminum alloy bottle with carbon fiber winding

High strength aluminum alloy 7075 was used as a hydrogen bottle material in this study. Gas tungsten arc welding was performed, and Taguchi method was applied to determine the aspect ratios of the melting area and obtain the optimal parameters and welding conditions of different locations. The solution treatment after post-weld artificial aging heat treatment, with or without weld metal and welding filler after non-heat treatment, and the mechanical properties of hardness and microstructure were also discussed. Heat treatment after welding and microhardness of the weld was increased by approximately 43% with filler.The welded junction is a vulnerable area in hydrogen bottles, thereby posing a threat to human safety. Therefore, this study simulated the tensile strength at welding area and used different types of carbon fiber windings to improve tensile strength, which reached 520.551 kgf at 4 °C.With carbon fiber winding, the optimum hydraulic test results that reached 60 kgf/cm2 were derived from a welding bottle. Comparing the bare bottle strength of 20 kgf/cm2, the data of carbon fiber winding is three times more than the bare bottle.In the end, more studies on strength enhancement applications should be considered in the future.

Microstructural characteristics of the laser welded joint of ITER correction coil sub case

The ITER correction coil (CC) case reinforces the winding packs against the electromagnetic loads, minimizes stresses and deformations to the winding pack. The cases are made of high strength and high toughness austenitic stainless steel (316LN) hot rolled heavy plate and have a thickness of 20mm. Considering the small cross-section and large dimensions of the case, deformation of the case when welding becomes a challenge in the case manufacturing. Therefore, laser welding was developed as the main welding technology for manufacturing. In this paper, multi-pass laser welding technology is used, the laser weldability of a 20mm thick 316LN austenitic stainless steel plate is studied and the microstructure of the welded joint is analyzed. The welding experiment used an YLS-6000 fiber laser (IPG) and weld filler of 316LMn to match the base metal was used. The result shows that the welded joint has no obvious surface and internal defects based on the optimized welding parameters. The weld joint have a fine austenite microstructure and display columnar dendrites and cellular grains with strong directional characteristics. No apparent heat affected zone is observed and approximately 2μm an austenite microstructure of the fusion line is clearly presented.

EFFECT OF FILLER ON WELD METAL STRUCTURE OF AA6061 ALUMINUM ALLOY BY TUNGSTEN INERT GAS WELDING

Innovative welding technology for joining Aluminum alloys in automobile, aviation, aerospace and marine industries would achieve weight reduction, high specific strength as well as increase the fuel efficiency and reduce the environmental pollution. This research introduced appropriate welding filler selecting to joint similar AA6061 aluminum alloys by Tungsten Inert Gas (TIG) process. TIG welding of AA6061 was butt joined with three different filler which are ER5356 (4.5-6% Mg), ER4043 (4.5-6% Si) and ER4047 (11-13% Si). The experiments are conducted in order to investigate the macrostructure and microstructure of the samples as well as mechanical properties. The effect of preheating was also investigated. The effect of different filler used on weld joint was analyzed by its visual appearance, microstructures, hardness and strength. It was found that, welding using filler ER5356 produced finer grain size at fusion zone is 25.69 µm compared to filler ER4043 and ER4047 with the grain size of 52.75 µm and 76.78 µm, respectively. ER5356 specimen also shows highest hardness value which is 72.9HV compared to ER4043 and ER4047 counterpart, which is 59.3HV and 57.6HV, respectively. As for tensile test result, the weld joints using filler ER5356 has highest strength which is 171.53 MPa compared to weld joints using ER4043 and ER4047 filler with value 167.34 MPa and 168.03 MPa, respectively. It can be concluded that TIG welding using ER5356 filler yields better joint compared to ER4043 and ER4047.