Showing 30 results for Aluminum
N. Marchin, A.r. Soltanipoor, K. Farmanesh,
Volume 5, Issue 2 (1-2020)
Abstract
In this study, the effect of tool's advance velocity on the mechanical behavior of the Al-7075 alloy during friction stir welding was simulated. In this simulation, the Lagrangian method with rigid-Visco-plastic material was used. The results of the process temperature obtained by the simulation method were verified by the experimental welding test. Using the characteristic stress, strain and temperature relationships in the Al-7075 alloy, the changes and the relationship between the material strength during the welding process by simulation was studied. The generated simulation defects was verified by experimental test.
M. Belbasi, M. Rezae,
Volume 5, Issue 2 (1-2020)
Abstract
Today in addition to Join by friction stir welding, the composite fabrication process is also performed simultaneously. The main purpose of the present research is to investigate the effect of pin geometry on the property of Aluminum 6061- alumina nanocomposite created by friction stir welding. For this purpose friction stir welding was carried out by selecting five types of pin geometries on Aluminum 6061 in which Al2O3 particles were deposited and the samples were examined by tensile and hardness tests, optical and electron microscope. Samples were investigated by tensile and hardness test, optical and electronic microscopy. Regular hexagonal pins due to having six smooth face and impulsive movement during rotation, caused a good perturbation which resulted in maximum tensile strength and elongation percentage of 198 MPa and 10.25 and minimum grain size of 13.3 micron, respectively. In the sample welded by a threaded cylindrical pin due to non-impact during rotation, inappropriate flow of reinforcing particles and its accumulation at perturbation the lowest tensile strength and elongation percentage of 133.5 MPa and 1.95%, respectively, were observed.
Ramin Delir Nazarlou, Dr Faraz Omidbakhsh, Dr Javad Mollaei Milani,
Volume 6, Issue 1 (8-2020)
Abstract
Friction stir welding (FSW) is an economic and high quality technique at aluminum welding and joining methods. The most important factor in the soundness of this type of welding, is the mechanism of material transfer in each tool rotation. The materials transfer during the welding process involves horizontal and vertical movement that caused by extrusion process and forging force (the tilt angle due to forging force and on the other hand, shape of pin due to the extrusion process). One of the most important parameters in FSW process is the effect of rotational speed in the welded zone. In this study, the effect of rotational speed at constant welding speed, in the butt joint of pure commercial aluminum, was investigated. The results of the study showed that, increasing the rotational speed due to increases the amount of material transfer in the weld zone. The welded zone was investigated by appearance weld zone experiments and using radiography tests. Also weld zone was investigated in macro and microstructure by using cross section. Then the micro hardness testing has been used by cross section at welded zone. In order to investigate the mechanism of materials transfer during the process, the electrical resistivity test has been used to analyses the amount of materials transfer in the weld zone. Results shows that, increasing rotational speed due to increasing the amount of materials transfer in the weld zone and decreasing the amount of defects in the weld zone.
S. A. A. Hashemi Milani, R. Tavangar, M. Azadbeh, Kahinpoor, H. Sadeghi-Nasab,
Volume 6, Issue 1 (8-2020)
Abstract
During the brazing of aluminum-based heat exchangers, the flux dry-off temperature plays a crucial role to get sound joints with maximum strength. In the present study, the NOCOLOK® flux consists of two phases of K2AlF5.H2O and KAlF4 with a melting point around 580 °C was used for brazing AA3003 as base metal with a clad-coating of AA4343 as filler metal. The slurry was applied on the joints and they dried at 220, 300 and 380 °C in air. The tensile shear test revealed that when the slurry dried at 300 °C, the joint withstand maximum shear stress of 44 MPa without defective features. At 220 °C and 380 °C, joint shear stresses were 34 MPa, 30 MPa respectively. However, drying at 380 °C under protective nitrogen gas enhanced the shear strength of up to 39 MPa. Having applied a change in current dryer temperature in the factory from 360 °C to 300 °C reduced the percentage of heat exchangers leakage from 3.2% to 0.6%, approximately, on a weekly basis.
H. Ebrahimzadeh, H. Farhangi,
Volume 6, Issue 2 (12-2020)
Abstract
The non-continuous laser beam in pulsed lasers allows the mechanical peening between two consecutive beams on a still hot weld bead. At a very short time (20, 150 and 300 ms) after laser pulse application, mechanical peening was performed on the welding bead. To achieve these short times, the light sensor detects the nth laser pulse and the mechanical arm starts moving. Upon reaching the tip of the pin near the workpiece, the n + 1th pulse was irradiated to the workpiece surface, and so the pin impact to the weld bead after traveling a short distance. Desirable mechanical properties were obtained at the highest time (300 ms) and highest pressure (6 bars). In this time and pressure the weld beads were not broken due to bending forces of peening.
Y. Ghorbani Amir, A. Zolriasatein, H. Torabian,
Volume 6, Issue 2 (12-2020)
Abstract
The aim of this study is to investigate the effect of rotary frictional welding process variables on microstructure, mechanical and physical properties of copper-aluminum dual-tube pipes. For this purpose, using a thermosetting friction welding machine, a copper pipe (99.44% purity) with a similar diameter aluminum tube (1050), was welded in three different conditions with different friction pressures and forging, and then by metallographic, hardening and microstructural testing it placed. The results of this study showed that with increasing friction pressure from 10 and 15 Bar respectively, in the interconnected phase, fuzzy interclass metal samples were created and caused a great loss in the deformation percentage and tensile strength of the interconnected sample. Also, with the reduction of frictional pressure and the removal of forging pressures down to 5 Bar, there is no proper bond between the two samples and formed in the interface between porosity and cracking. The most suitable result for the microstructure, mechanical and physical properties of the samples is in tubes with an outside diameter of 15 mm and an inner diameter of 10 mm, for samples having a friction pressure of about 10 Bar and a forge pressure of 15 Bar. The presence of intermetallic Al-Cu phases such as CuAl2, due to higher electrical resistance and ceramic nature, increases the electrical resistance of the joint and, on the other hand, the presence of cracks and pores has reduced the flow rate and eventually increased electrical resistance of the samples
M. Safari, H. Deilami Azodi ,
Volume 6, Issue 2 (12-2020)
Abstract
In this paper, the experimental investigation of formability of friction stir welded ultra-thin sheets of IF steel is investigated experimentally. First, the sheets are joined by friction stir welding process based on the tests determined according to the Taguchi design of experiments. The investigated parameters in the welding process are as tool rotational and traverse speeds. Then, the tailor welded blanks are formed based on dome height test up to the defect stage and the dome height is measured for each test. Therefore, the effects of friction stir welding process parameters on formability of friction stir welded ultra-thin sheets of IF steel are evaluated. The results show that by increasing the rotational speed, the dome height in forming process decreases, while with increasing the traverse speed, the formability of tailor welded blanks by friction stir welding process improves. Also, the results of optimization based on signal to noise ratio method show that the tool rotational speed has the greatest effect on the dome height of tailor welded blank.
R. Karimpoor, A. Farzadi, A. Ebrahimi ,
Volume 7, Issue 1 (8-2021)
Abstract
In the present study, effect of current, welding speed and preheat temperature during FB-TIG welding of AA5083 aluminum alloy was studied. Using the Taguchi method, 9 different tests were designed to investigate the effect of welding parameters on the penetration depth. Consistent with predictions, increasing the current and preheat temperature, and reducing the welding speed led to an increase in penetration depth. The maximum penetration depth of 8.02 mm was achieved at the current of 220 A, welding speed of 120 mm/min, and the preheat temperature of 100 °C. Taguchi analysis showed that increasing the welding current and preheat temperature had a more significant effect than the welding speed. Microstructural analysis indicated that the weld metal is fine-grained, along with coarse-grain in the HAZ of all samples. Many pores were observed in the samples with high welding speed and high welding current in the fusion zone. The sample with the highest heat input had the highest penetration depth. This sample had the highest elongation, equal to 69% of the base metal. Moreover, microhardness test demonstrated that the hardness of this sample dropped sharply from 70 Vickers to 58 Vickers in the HAZ.
M. Alimadadi, M. Goodarzi, S.m.a. Boutorabi,
Volume 7, Issue 1 (8-2021)
Abstract
This present study aimed to create an Al6061-St52 dissimilar joint and investigate the effect of the transverse speed by the friction stir welding process. Welding aluminum to steel is rugged by fusion methods because of the formation of brittle intermetallic compounds (IMCs). Therefore, to designate optimal parameters, acceptable IMC thickness, and mechanical properties determined. This research carried out different three transverse speeds of 16, 40 and 85 mm/min (with a constant pin offset of 0.2 mm). Geometry of tool's pin radius and height is 4mm and 1.8mm, respectively. In the transverse speed parameter, the highest ultimate tensile strength (UTS) of 200 MPa was obtained at 85 mm/min. According to the Energy Dispersive X-ray Spectroscopy results, an IMC layer formed in the joint interface. The heat input rate was calculated to designate the optimal parameters. In tensile specimens, fracture mainly occurred in the joints and within the aluminum stir zone due to the combination of thick IMC layer and steel fragments, respectively. The micro-hardness measurement results showed that at (85 mm/min) the hardness values were HV 75 in the aluminum stir zone and HV 315 in the AS vicinity of the interface region. This hardness value is much higher than the base metals (Aluminum base metal is an average of HV 53 and an average steel base metal of HV 245).
Mr. N. Taheri Moghaddam, Dr. A. Rabiezadeh, Dr. A. Khosravifard, Dr. L. Ghalandari,
Volume 7, Issue 2 (1-2022)
Abstract
Conventional fusion welding of aluminum alloys results in coarse-grained structure, inevitable defects, and significant softening in the welding region. Friction stir welding with bobbin tool is a technique of friction stir welding method that has a great potential for developing applications of friction stir welding method in marine, aerospace, and automotive industries due to having an extra shoulder. Sheets of 5083 aluminum alloy with a thickness of 3 mm were welded using the bobbin tool friction stir welding method to assess the feasibility of similar joining. The effect of different process variables such as shoulder pinching gap, transverse speed and tool rotation speed was investigated. The results showed that a sound joint is achieved at a transverse speed of 13 mm / min and a tool rotation speed of 1350 rpm. The results of tensile test showed that the obtained joint efficiency is 94.5%, which is higher than the joint efficiency of fusion methods and comparable to the joint efficiency of conventional friction stir welding. Microscopic evaluation of the fracture surface of welded specimens showed that for similar joints, the dominant fracture mechanism is ductile fracture.
Dr. Seyedeh Zahra Anvari, Eng. Meysam Khandozi,
Volume 7, Issue 2 (1-2022)
Abstract
In the present study, to resolve the problems in fusion welding methods as well as to increase the strength, FSW method was used to join aluminum alloy sheets 6061 and 2024. Moreover, optimal parameters for joining of these two alloys were also taken into consideration. Various tool rotation speeds of 565, 950 and 1500 rpm were selected. For each tool rotation speed, two traverse speed variables, two penetration depth variables, and two tool angle variables were specified. The analysis of mechanical properties of welded samples was conducted through tensile and micro-hardness tests. Furthermore, microstructure of welding zone was investigated using optical and electron microscopes. The ratio of shoulder diameter to pin diameter is among the most significant and practical factors for welding tools. So, a shoulder diameter three times larger than that of pin diameter was selected. In the present study, alloy 2024 was placed at the precursor as the harder alloy. Tensile strength and indentation hardness of optimal specimen 300 MPa and 85 HV were achieved. Moreover, hardness behavior and tensile strength of heat-affected zone (HAZ) was evaluated to be lower in alloy 6061 compared to other zones.
M. Foumani, H. Naffakh-Moosavy, A. Rasouli, H. Aliyari,
Volume 8, Issue 1 (8-2022)
Abstract
Surface roughness in the welding processes is one of the important parameters in the laser welded metal connections which affects laser beam absorption directly. When the laser beam is irradiated to the surface of the base metal, the surface roughness plays an important role in the amount of beam absorption and the amount of melting achieved and directly affects the penetration depth. The main purpose of this study is to investigate the effect of roughness mentioned above in the equal parameter for this widely used aluminum alloy. Microstructural Surveys were performed on three different roughness levels of the sample and the results obtained from the analysis of samples by optical microscope (OM), atomic force microscope (AFM) and Scanning electron microscopy (SEM) analysis showed that, increasing the surface roughness up to Ra = 0.16 micrometer, caused the greater degree of beam engagement by the surface grooves, hence more concentration of the beam photons and more melting obtained, so the depth of penetration increases by consuming a lower amount of energy.
N. Taheri Moghaddam, A. Rabiezadeh, A. Khosravifad, L. Ghalandari,
Volume 8, Issue 2 (1-2023)
Abstract
Despite the increased use of aluminium alloys in several industries, their common concern is the difficulty of joining dissimilar alloys using welding techniques. Based on this, the primary purpose of this research is to assess the mechanical characteristics of dissimilar joining of heat-treatable 6061 and non-heat-treatable 5083 aluminium alloys by gas tungsten arc welding and to discover the link between microstructure and mechanical properties. Similar welds were also implemented and evaluated in order to more properly analyze and compare the outcomes. The quality of the weld generated after establishing the health of the joint using non-destructive testing was evaluated by destructive bending, tensile, metallographic, and hardness tests to check the mechanical and microstructural qualities. The intended dissimilar weld was produced under the parameters of pulse current 120-80 amps, voltage 20 volts, welding speed 15 cm/min, and filler 5356. It should be highlighted that the dissimilar weld had the maximum joint efficiency, and with perfect control of welding settings and the absence of flaws, only 36% loss of strength was recorded when compared to the base metal. Metallographic images revealed that the formation of hot cracks in the dendritic structure of the weld metal is the major cause of strength loss for 5083 similar weld and the production of numerous porosities in the weld metal for 6061 similar welds.
M. Ahmadi, H.r. Ahmadi, M.r. Khanzadeh, H. Bakhtiari,
Volume 9, Issue 1 (5-2023)
Abstract
In this research, friction stir welding of aluminum 1050 to copper with variable speed was investigated. For friction stir welding, rotational speeds of 900 and 1200 rpm and traverse speeds of 36, 63, and 125 mm/min were used. In order to check the phases and microstructure, scanning electron microscope analysis, X-ray spectrometry, and hardness testing were used. The disturbance zone included Al2Cu3, Al4Cu9, AlCu4, Al2Cu, and AlCu phases. The results showed that the formation of intermetallic phases and severe plastic deformation in the welding area caused an increase in hardness. The highest hardness value in the stirred area was 97.8 Vickers at a rotation speed of 900 rpm and an advance speed of 36 mm/min.
A. Lalpour, M. Mosallaee, A. Ashrafi,
Volume 9, Issue 1 (5-2023)
Abstract
In the present study, friction stir processing (FSP) technique was carried out on the AA2024 sheet at different traverse speed (63 to 250 mm/min) and rotation speed (315 to 800 rpm). The temperature and grain size of stirred zone (SZ) were measured and their relationship was analyzed and effect of FSP parameters on the grain size of SZ was determined. Experiment and analytical investigations revealed that SZ grain size complies the exponential temperature-dependent relationship and can be defined the mathematical equation. Calculations indicate that a change in operational variables (rotation and traverse speeds) makes no variation in strain rate, and it is constant.
M. Naseri Alenjagh, T. Saeid,
Volume 9, Issue 1 (5-2023)
Abstract
The purpose of this research is to investigate the change of rotational speed and traverse speed on the microstructure and mechanical properties of the joint in friction stir welding of aluminum 1050 and 316L stainless steel. For this purpose, the microstructure, thickness of intermetallic compounds, hardness and tensile test on the joint were investigated. The proper selection of welding parameters leads to the creation of a joint with suitable metallurgical and mechanical properties. In this research, two rotational speeds of 560 and 900 rpm and four traverse speeds of 60, 80, 100 and 125 mm/min were performed. The microstructure consisted of four areas of the base metal, heat affected zone, thermo-mechanical affected zone and stir zone. In all the samples, the stir zone (SZ) contained a recrystallization microstructure with fine equiaxed grains. According to the Energy dispersive X-ray Spectroscopy results, an IMC layer formed in the joint interface. The hardness of the stir zone in all samples was higher than the aluminum base metal due to the formation of recrystallization fine equiaxed grains and the presence of steel particles. The best sample in terms of mechanical properties, mocrostructure and joint quality was obtained in the conditions of rotation speed of 900 rpm and advance speed of 125 mm/min. The strength was equal to 84 MPa with 77% efficiency.
A. Gandomdoust, M. Sarkari Khorrami, S. F. Kashani-Bozorg, H. Ghorbani,
Volume 9, Issue 1 (5-2023)
Abstract
As one of the important pillars of the fourth industrial revolution, metal additive manufacturing (AM) technologies provide a disruptive approach to digital manufacturing. Laser powder bed fusion (LPBF), as one of these technologies, has great potential in producing geometrically complex and high-performance parts. In recent years, the manufacturing of aluminum alloy parts using this technology has attracted much attention. However, their manufacturing still faces some challenging issues. One of the most serious issues encountered in the manufacturing of aluminum alloys, especially high-strength grades, is solidification cracking. In the present investigation, the formation mechanisms of solidification cracking, and the associated effective factors were reviewed. Controlling the solidification microstructure and grain refinement, using the addition of small quantities (<1 wt.%) of micro- or nano-sized particles to the initial alloying powder, was suggested as the most effective method for reducing solidification cracking. These particles act as nucleation sites, prevent grain growth, pin grain boundaries, and with the help of factors that provide constitutional supercooling can effectively minimize solidification cracking. Eventually, effects of various additives in grain refinement and their associated mechanism in reduction of solidification cracks of high-strength aluminum alloys by LPBF is presented.
Dr. Mojtaba Movahedi, Hosseinali Shirovi Khoozani, Ashkaan Ozlati,
Volume 9, Issue 2 (8-2024)
Abstract
M.r. Hajiha, A. Farzadi, S. A. Samadani Agdam, A. Shabanzadeh, S. Ramezani,
Volume 9, Issue 2 (1-2024)
Abstract
5xxx and 6xxx series alloys are among the most widely used aluminum alloys in various industries, including automobile, shipbuilding and aviation industries. In this research, the joint of two alloys AA6061-T6 and AA5052-H12 was investigated at 4 transmission speeds of 60, 90, 120 and 180 mm/min and 3 rotation speeds of 600, 800 and 1000 rpm. These investigations were carried out in the condition that each of the two alloys was placed in two progressive and regressive sides. The results of these studies showed that the highest tensile strength is when the AA5052 sample is placed on the advancing side and the transfer speed is 90 mm/min and the rotation speed is 600 rpm, and in this case, the final tensile strength value is equal to 197 MPa. In addition, the results showed that, generally, the tensile strength decreases with an increase in the transmission speed at a constant rotational speed, and with an increase in the rotational speed at a constant transmission speed, the tensile strength increases. In addition, microscopic and macroscopic examination of the sections of all samples was performed and various areas and defects were examined. According to the investigations carried out on the microstructure, the grain size in the weld nugget compared to the base metal, HAZ and TMAZ decreases. The grain size in HAZ is the largest in all samples, and this causes a decrease in weld strength in this zone.
M.r Borhani, S.r. Shoja-Razavi, F. Kermani,
Volume 10, Issue 1 (6-2024)
Abstract
In this study, the effects of friction stir welding (FSW) parameters on the properties of dissimilar joints formed between 5083 aluminum alloys and 316L austenitic stainless steel, with a thickness of 4 mm, are investigated. The tool speed is varied in the range of 16 to 25 mm/min, while the tool rotation speed is maintained at a constant value of 250 rpm. To examine the microstructure of different weld regions, both optical and scanning electron microscopes are employed. To assess the mechanical properties, hardness and tensile tests are conducted. The results shows the formation of a composite region characterized by steel reinforcement particles dispersed within an aluminum matrix. At the steel-aluminum interface, a single layer of discontinuous intermetallic composition with a thickness of approximately 2 micrometers is observed. Notably, when the rotation speed is set to 250 rpm and the tool speed is 16 mm/min, a tensile strength of 298 MPa and ductility of 26% (93% of the tensile strength and 50% of the ductility of the 5083 aluminum alloy) are achieved.
