Showing 13 results for Aluminum Alloy
H. Rezaei Ashtiani, M. Shafiee,
Volume 4, Issue 1 (8-2018)
Abstract
Friction stir spot welding (FSSW) is a type of solid state welding that is used in the connection of small pieces and light metals such as aluminum alloy especially. The technical problem during melting of aluminum alloys is one of the most important reasons for developing application of friction stir welding for aluminum alloys. In this research, the effects of important processing parameters such as tool rotation speed, dwell time, plunge depth of tool and sheets thickness on the mechanical properties such as failure force and energy of FSS welded AA-3105 alloy have been experimentally studied using micro hardness and tensile tests. Tensile-shear tests show four different fracture modes of weld failure which consist of shear fracture, circumferential fracture, nugget pull out fracture and fracture in base material modes. The results show that the weld strength drops with increasing the tool rotation speed. Strength and hardness of weld and weld zone increase and then decrease with increasing dwell time of rotational tool which it can be obtained an optimum value of dwell time. Strength and fracture energy and load of welds increases with increasing the sheet thickness
I. Khodai Delouei, H. Sabet , V. Abouei Mehrizi,
Volume 4, Issue 2 (1-2019)
Abstract
Friction Stir Welding is one of the solid-state processes and today it has been used to join different types of materials. Friction stir welding does not have many problems and limitations due to melting and solidification of weld metal and by controlling its variables, the microstructure and desired mechanical properties can be achieved at the joint. Recently, in most industrial areas, due to its lightness and energy saving, much attention has been paid to the joining of aluminum alloys. The present study investigates the microstructure and evaluation of mechanical properties of friction stir welding in AA2024 and AA6061butt welds. A cylindrical threaded tool was used to join 5 mm thick plates at rotational speeds of 800, 1000 and 1200 rpm and traverse speeds of 30, 50, 70, 90 and 110 mm / min. In order to perform the necessary investigations, metallurgical observations were performed by optical microscope and scanning electron microscope equipped with a chemical analysis system of the elements, as well as mechanical tests of tensile strength and micro hardness. The results showed that the difference between the two alloys causes hardness variations in the nugget zone and a large hardness drop at the transition between the zone composed of both alloys and the 6061 zone. By increasing the traverse speed from 30 to 110 mm / min at constant rotational speeds of 800, 1000 and 1200 rpm, due to reduced input heat, the grain size decreases and the hardness and strength increase. Also, the highest tensile strengths and hardness were 221.6 Mpa and 111.05 Vickers, respectively, for a sample welded at a rotational speed of 1000 rpm and a traverse speed of 110 mm / min.
A. Abdollahzadeh, A. Shokuhfar,
Volume 5, Issue 1 (9-2019)
Abstract
In this study, friction stir butt welding of Mg and Al alloys with applying Zn interlayer was performed. To obtain optimum condition, a combination of two travel and three rotation speeds were selected. Mg-Zn and Mg-Al-Zn IMCs, Al solid solution and residual Zn, were the most common phases in the stirred zone, which eliminated the formation of Al-Mg intermetallics. The maximum mechanical properties were achieved for the joint fabricated at 35 mm/min and 600 rpm, caused to 24% improvement in tensile strength and around 3 times enhancement of elongation compared with Zn free sample FSWed at the same conditions. The fracture micrographs were consistent with corresponding ductility results. Fracture surfaces of Zn-added samples presented a fine texture with a mixture of brittle and ductile fracture feature, which was different from the coarse cleavage plane and fully brittle fracture of the joint without Zn interlayer.
R. Narimani, M. Eliasi, M. Hosseinzadeh, H. Aghajani Derazkola,
Volume 5, Issue 1 (9-2019)
Abstract
Dissimilar joint with good quality and mechanical properties is one of the major problems the industries. One of the most commonly used methods to solve this problem is friction stir welding process. In this paper two different tool pin with simple cylindrical and screwed profile were used to finding optimization of friction stir welding parameters to reach best mixing flow, composite structure and maximum tensile strength in dissimilar joint between AA6065 aluminum alloy and pure copper. In this research 1130 rpm tool rotation, 24, 40 and 65 mm/min travelling speed, 0.3 mm plunge depth and 3o tool tilt angle were carried out. The results shows that internal material flow that produced with screw pin was better than simple cylindrical in constant process parameters. According to the results, at lower tool travelling speed the strength of joint increases. The tensile test results revealed the maximum strength of joint of screw pin was 345MPa with 2.6mm elongation and simple cylindrical pin was 272MPa with 2.2mm elongation which welded with 1130 rpm and 24 mm/min travelling speed.
R. Tamasgavabari, A. Ebrahimi, S. M. Abbasi, A. Yazdipour ,
Volume 5, Issue 1 (9-2019)
Abstract
In this research, the effect of vibration at the resonant range (75 Hz) on the hardness and tensile strength of AA-5083-H321 aluminum alloy, were welded by gas metal arc welding (GMAW) investigated. Vibration forces were ranged from 850 N to 2200 N, under identical welding parameters. Tensile strength and hardness testing of welded samples were performed. After mechanical tests, the fracture surfaces of welds were examined using scanning electron microscope (SEM) and discussed. The results showed that with increasing vibration force, the tensile strength and fracture strength of the specimens were welded during vibration, were increased by about 3 and 9 percent, respectively, compared to the non-vibrated weld sample. However, no significant change was observed in the hardness of the welded specimens. Mean grains size and heat affected zone of the sample was welded was welded with conventional GMAW, were about 200 μm and 1800 μm, but due to inducing vibration, as vibration force increased from 850 N to N 2200 N, Mean grains size was reduced to about 75 μm and HAZ was reduced from about 1000 μm to 700 μm, that is, about 44 to 61%.
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.
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.
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.
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.
Mohammad Reza Borhani, Reza Shoja Razavi, Farid Kermani,
Volume 9, Issue 2 (8-2024)
Abstract
In this study, the effect of friction stir welding (FSW) parameters on the dissimilar joint properties of 5083 aluminum alloys and 316L austenitic stainless steel, with a thickness of 4 mm, has been investigated. The tool speed was considered in the range of 16 to 25 mm/min, and the rotation of tool speed was considered to be equal to a constant speed of 250 rpm. To check the microstructure of different weld areas, optical and scanning electron microscopes were used, to check the mechanical properties, hardness and tensile tests were performed. The results showed the formation of a composite region consisting of steel reinforcement particles in the field of aluminum.
At the steel-aluminum interface, a single layer of discontinuous intermetallic composition with a thickness of about 2 micrometers was observed; Also, by choosing the rotation speed of 250 rpm and the tool speed of 16 mm/min, the tensile strength equal to 298 MPa and ductility of 26% (93% of tensile strength and 50% of ductility of aluminum 5083 alloy) were obtained.
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.
