Showing 8 results for Sadeghi
B. Sadeghian, M. Atapour, A. Taherizadeh ,
Volume 1, Issue 1 (Journal OF Welding Science and Technology of Iran 2016)
Abstract
Today, steel to aluminum joints are used to facilitate transportation and fuel consumption. These joints are applied from nuclear, aerospace and naval to automobile and kitchen industries. According to previous studies fusion welding processes are not suitable methods for these joints, solid-state welding, especially friction stir welding, is a proper way to use for these joints. However, using this method for these two metals needs adequate prediction of temperature distribution and material flow to obtain enhanced joints. In this study, a finite element method is used to predict the temperature distribution. In addition, a computational fluid dynamics solution is coupled with the thermal solution. Therefore, the flow rate, strain rate and dynamic viscosity is obtained. Also, the joint morphology is predicted using the Level Set method. It is shown the material flow depends on flow rate, strain rate and dynamic viscosity and is intensively function of rotational speed. Additionally, offset to the aluminum side improves the morphology of the stir zone.
M. Sadeghi Gogheri, M. Shabani, E. Mirzapour, M. Kasiri, K. Amini,
Volume 2, Issue 1 (Journal OF Welding Science and Technology of Iran 2016)
Abstract
In this study, commercially pure titanium and aluminum alloy 5083 in connection rotational speed of 1120 rpm and a feed rate of 50 mm per minute for butt welding by friction stir welding has been successfully completed. Micro-structure, hardness and tensile test was conducted on the connection. Welding area is a composite of aluminum and titanium particles that the particles plays an important role in increasing hardness and tensile strength. Welding area is also has three areas. Vickers hardness is 480 times the area of welding means that the hardness in the area of the base metal of titanium and aluminum increased by 16% and 60% for titanium aluminum intermetallic compounds is created in the area is weld.
Hamid Gharaei, Mahdi Salehi, Mehran Nahvi, Behzad Sadeghian,
Volume 2, Issue 2 (Journal OF Welding Science and Technology of Iran 2016)
Abstract
In this research, artificial neural network (ANN) and genetic algorithm (GA) were used in order to produce and develop the NiAl intermetallic coating with the best wear behavior and the most value of hardness. The effect of variations of current, voltage and gas flow on the hardness and wear resistance were optimized by ANN and GA. In the following, the optimum values of current, voltage and gas flow were obtained 90(A), 10(v) and 9 (Lit/min), respectively. Then, the wear behavior in the environment temperature and high temperature for optimized NiAl compound was compared with two other experimental samples.
B. Sadeghi, H. Sharifi, M. Rafiei,
Volume 3, Issue 1 (Journal OF Welding Science and Technology of Iran 2017)
Abstract
In this research, the microstructure and mechanical behavior of dissimilar joint of AISI 321 stainless steel to ASTM A57CL1 were studied. For this purpose, the GTAW process and ER 308L filler metal with diameter of 1.8 mm were used. In order to study the microstructure and fracture surface of weld samples, optical microscope and scanning electron microscope (SEM) were used. Also, the mechanical behavior of the joint was examined by impact, tension and microhardness tests. It was found that the microstructure of weld metal was austenite with skeletal ferrite. Also in some areas the lacy ferrite was seen. All samples were fractured from ASTM A537CL1 steel with a ductile manner during the tension test. The weld metal indicated high impact energy about 205 J.
B. Sadeghian, A. Taherizadeh, M. Atapour, T Salehi, M Nosouhian,
Volume 3, Issue 1 (Journal OF Welding Science and Technology of Iran 2017)
Abstract
Aluminum to stainless steel joints are broadly used in industries in order to reduce fuel consumption. While fusion welding is not a suitable method to join these metals. solid state welding, like friction welding (FW), is an effective way to this process. However, risk of intermetallic compounds (IMCs) formation is probable in these welds. In previews investigations formation of FeAl3, Fe2Al5 and Fe4Al13 is reported. In this study, effect of different parameters on generated heat and temperature distribution that lead to formation of these compounds in a FW of aluminum alloy to stainless steel is investigated using Finite Element Method (FEM). Additionally, a mathematical modeling of the parameters is performed using Artificial Neural Network (ANN) and the optimum level of the parameters has been found.
B. Sadeghi, M. Shamanian, F. Ashrafizadeh, P. Cavaliere,
Volume 4, Issue 2 (Journal OF Welding Science and Technology of Iran 2019)
Abstract
Solid state joining of powder metallurgy (P/M) processed and sintered by spark plasma sintering through friction stir welding (FSW) was studied. The nanocomposites were prepared via mechanical milling followed by spark plasma sintering. The microstructural and mechanical of the joints were evaluated as a function of the different processing parameters such as rotating and advancing speeds of the tool. The achieved finding revelled that the FSW of the nanocomposites produced by P/M containing bimodal sized Al2O3 reinforcement have a working window are affected by the heat input. The joint evolution revelled that the microstructure and mechanical properties of those was related to the generated heat input during the welding. It is known that dynamic recrystallization (DRX) caused grain size refinement of aluminium into stir zone. Meanwhile, it was revealed that the pinning effect of Al2O3 nanoparticles retarded grain growth of the recrystallized grains caused by dynamic recrystallization (DRX)
S. A. A. Hashemi Milani, R. Tavangar, M. Azadbeh, Kahinpoor, H. Sadeghi-Nasab,
Volume 6, Issue 1 (Journal OF Welding Science and Technology 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.
A. Etemadi, M. Kasiri-Asgarani, H. R. Bakhsheshi-Rad, M. Sadeghi Gogheri,
Volume 9, Issue 2 (Journal OF Welding Science and Technology 2024)
Abstract
In this research, dissimilar joining of biodegradable AZ31 alloy to Ti-6Al-4V titanium alloy by rotary friction welding method was investigated with aim of preparation of pin or screw for orthopedic applications. optical and scanning electron microscope (sem) were used to investigate the microstructure, x-ray diffraction was conducted for phase analysis, torsion and micro-hardness tests were carried out to investigate mechanical properties, and polarization and electrochemical impedance spectroscopy were employed to evaluate corrosion resistance. in the welding procedure, rotational speed of 1100, 1200 and 1300 rpm and friction time of 2 and 4 seconds were considered as variable parameters, and two parameters of friction pressure and forge pressure were considered as constant parameters at 50 and 40 MPa, respectively. The microstructure of the joint zone showed that there is no deformation in the titanium alloy side. However, in the magnesium side, the greatest amount of deformation occurred with the distance from the joint line, where weld center zone (CZ), dynamic recrystallization zone (DRX), thermomechanical affected zone (TMAZ) and partial deformation zone (PDZ) are detected. The formation of intermetallic phases such as Mg2AlZn, Ti3Al and also the refining the grains size is the main reason for increasing the hardness of the magnesium side near the joint line up to 150 HV. The results of the torsion test showed that the welded sample has the highest shear strength of 81.51 MPa and also the highest corrosion resistance among other samples at a rotation speed of 1200 rpm and a friction time of 4 seconds.
