Showing 7 results for Mosallaee
M. Mosallaee, F. Dehghantalebi , S. Ghasemi , A. Mashreghee,
Volume 1, Issue 1 (Journal OF Welding Science and Technology of Iran 2016)
Abstract
Cellulose is a natural biopolymer with the general (C6H10O5)n formula, which according to AWS A5.5 standard, more than 40wt% of coating of cellulosic electrodes is consisted of cellulose. In this study to evaluate the effect of cellulose type on the performance of E8010-P1 cellulosic electrode, equal amounts of two celluloses with the same commercial properties but produced by two different companies, were used for production of two E8010-P1 electrodes.Experimental studies illustrate significant difference between structural and mechanical properties of deposited weld metals from these electrodes. FTIR, DTA and XRD testes of as-received celluloses show despite the same brandforthese celluloses, their properties such as bonds types,thermal behavior and crystallinity are different that cause variation ofweld metal penetrate and tensile strength around 25±2% and 5±2%respectively.
A. Ghaedrahmati, M. Mosallaee Pouryazdi,
Volume 3, Issue 1 (Journal OF Welding Science and Technology of Iran 2017)
Abstract
A517 is a low alloy high-strength steels that due to its high strength, toughness and weldability is used in ship building and submarine hulks. The welded areas of this steel often require repairs. In this study, the effect of number of welding repair on microstructure and mechanical properties of A517 steel is studied. Four samples (samples without repair, once repaired, twice repaired, and three times repaired) were welded by SMAW welding. Microstructural studies were carried out by using optical and scanning electron (SEM) microscopes. The effect of the number of repairs on mechanical properties of samples were investigated by using tensile, bending, impact and hardness The profile of hardness illustrated that the hardness in the heat affected zone near the base metal increased by repeated repairs while the hardness of this zone reduced in the third repaired sample. By repeating the welding repair, tensile and yield strengths of the welding areas were reduced and fracture impact toughness of heat affected zone at -51○C was increased. Generally, the results of tensile tests of second and third repaired indicated that the strength of these samples were not meet the ASME IX standard requirements, so welding steel A517 in the second and third repairs is not acceptable.
M. Toghraei Semiromi, M. Mosallaee Pouryazdi, M. Kalantar, A. Seifoddini,
Volume 5, Issue 1 ((Journal OF Welding Science and Technology 2019)
Abstract
In the present study, effect of Ni alloying element on the characteristics of deposited weld metal of E7018-G electrode was evaluated. Therefore, electrodes contained different amounts of Ni (0-1.7wt.%) were designed, manufactured and welded via SMAW process. Microstructural studies revealed dichotomy effect of Ni on the deposited weld metal microstructure, i.e. increasing the Ni content up to 1.2wt.% improved the formation of acicular ferrite in the weld metal microstructure and caused significant grain refinement at the reheated zone of weld metal. While, higher Ni content (>1.2wt.%) resulted in some raising in the widmannstatten ferrite content in the weld metal. Strength multiplied by impact energy parameter (UTS×CVN) was used for mechanical properties assessment. Mechanical properties evaluation revealed the highest UTS×CVN parameter achieved in the weld metal contained 1.2wt.% Ni. Hardness of the weld metal increased with increasing Ni content which is related to the formation of micro constituents in the microstructure of weld metal and increasing their content with increasing Ni content.
S. A. Beheshti Bafqi, M. Mosallaee,
Volume 6, Issue 2 (Journal OF Welding Science and Technology 2020)
Abstract
In the present study, the transient liquid phase bonding of AISI 2205 dual phase stainless steel with amorphous BNi-3 interlayer was carried out. Based on the initial experimental and analytical studies, the parameters of temperature and bonding time were determined. In order to investigate the effect of bonding temperature on the microstructural changes of the joint, bonding was performed in the temperature range of 1050-1200℃ for 20 min. The microstructural and phase analyses indicated the completion of isothermal solidification and the formation of a uniform Ni-solid solution in the bonding zone centerline. The interdiffusion between the bonding zone and the adjacent base metal resulted in the formation of boride and nitride intermetallic compounds in the base metal adjacent to the bonding zone, which the area fraction of this intermetallics significantly decreased with increasing bonding temperature from 1050℃ to 1200℃ (reduction of the intermetallic area fraction from 85% to 40%). Evaluation of shear strength of samples showed that despite the completion of isothermal solidification in all samples and shear strength of bonded samples significantly depends of amount and morphology of intermetallic compounds on the transient liquid phase bonding shear strength. By increasing the bonding temperature to 1200℃ and reducing the area fraction of intermetallic compounds up to 40% of the shear strength of the samples increased from 450 MPa of TLP bonded specimen of 1050℃ to about 85% of base metal shear strength.
M. J. Bagban, M. Mosallaee Pour, H. Hajisafari, A. Babnejad, A. Saboori,
Volume 8, Issue 1 (Journal OF Welding Science and Technology 2022)
Abstract
In the present study, the microstructure and mechanical properties of the dissimilar joint of Inconel 625 (IN-625) superalloy to austenitic stainless steel AISI316L (SS-316L) via AWS-BNi3 interface layer and transient liquid phase (TLP) bonding process were evaluated and necessary conditions for creating an efficient joint were determined. TLP bonding was performed in temperature and time range of 1050-1150ºC and 5-20min, respectively, under the protection of argon shielding gas with a purity of 99.9995%. Microstructural (OM and SEM) and phase (XRD) studies revealed that bonding at 1150 ° C for 20 min results in completion of isothermal solidification and develops a uniform gamma (γ) phase at the bonding zone. Cooling the samples before completion of isothermal solidification results in the formation of chromium and molybdenum-rich eutectic compounds at the bonding centerline. The continuous morphology of the eutectic compounds caused a sharp drop in the shear strength of the specimens (~50% reduction of shear strength). The inter-diffusion of alloying elements between the bonding area and the surrounding base metal results in the formation of chromium carbide in the IN-625 and chromium- boron compounds in the SS-316L, which increased the microhardness of these areas compared to the base metals and the bonding zone.
A. Lalpour, M. Mosallaee, A. Ashrafi,
Volume 9, Issue 1 (Journal OF Welding Science and Technology 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. Mosallaee, A.h. Morshedy,
Volume 9, Issue 2 (Journal OF Welding Science and Technology 2024)
Abstract
In this research, the optimization of the artificial neural network (ANN) capability for predecting the tensile strength and elongation of friction stir welded Al-5083 (FS-welded Al-5083) was carried out. The effective parameters of ANN, such as the number of layers, number of neurons in hidden layers, transfer function between layers, the learning algorithm and etc. were investigated and the efficient neural network was determined to predict the tensile properties of FS-welded Al-5083. The investigations revealed that the perceptron neural network with two hidden layers and 17 neurons numbers, Lunberg-Marquardt training algorithm and Logsig transfer function for the intermediate layers and Tansig transformation function for the output layer is the most optimized neural network for the prediction. The optimized network has an optimal structure based on the minimum value of the mean square error of 0.05, the maximum total correlation coefficient of 0.93 and the line regression with an angle of 45 degrees between the actual and estimated values. Therefore, this network has a good performance for training, generalizing and estimating of tensile strength and elongation of FS-welded Al-5083.
