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    Laser welding of NiTi shape memory alloy: Comparison of the similar and dissimilar joints to AISI 304 stainless steel [electronic resource]

    , Article Optics and Laser Technology ; Volume 54, 2013, Pages 151–158 Mirshekari, G. R. (Golamreza) ; Saatchi, A ; Kermanpur, A ; Sadrnezhaad, K ; Sharif Univercity of Technology
    The unique properties of NiTi alloy, such as its shape memory effect, super-elasticity and biocompatibility, make it ideal material for various applications such as aerospace, micro-electronics and medical device. In order to meet the requirement of increasing applications, great attention has been given to joining of this material to itself and to other materials during past few years. Laser welding has been known as a suitable joining technique for NiTi shape memory alloy. Hence, in this work, a comparative study on laser welding of NiTi wire to itself and to AISI 304 austenitic stainless steel wire has been made. Microstructures, mechanical properties and fracture morphologies of the... 

    Double layer bioglass-silica coatings on 316L stainless steel by sol-gel method

    , Article Ceramics International ; Volume 40, Issue 1, Part A , January 2014 , Pages 993–1000 Pourhashem, S ; Afshar, A ; Sharif University of Technology
    The application of bioglass coatings on metallic implants provides link between bone and materials and prevents corrosion of metallic implants in body fluid. Therefore, in this research, 45S5 bioglass-silica coatings on 316L stainless steel were prepared by the sol-gel method and were characterized by different techniques. According to X-ray diffraction (XRD) results, by sintering 45S5 bioglass at 600 C for 5 h, coatings containing both amorphous phase and Na2Ca2Si3O9 crystalline phase were obtained. Scanning electron microscopy (SEM) results showed that coatings prepared via appropriate sol aging and substrate preparations are crack-free. Potentiodynamic polarization tests in simulated body... 

    Titania nanostructured coating for corrosion mitigation of stainless steel

    , Article Protection of Metals and Physical Chemistry of Surfaces ; Vol. 50, issue. 3 , 2014 , p. 371-377 Barati, N ; Sani, M. A. F ; Sadeghian, Z ; Ghasemi, H ; Sharif University of Technology
    Anatase nanostructured coating has been prepared on 316 L stainless steel by sol-gel dip coating. The topography of the coatings surface has been analyzed using atomic force microscopy. The anticorrosion performance of the coatings has been evaluated using polarization curves. Effects of calcination temperature, withdrawal speed and times of coating on corrosion protection have been studied. The results showed calcination temperature of 400°C and withdrawal speed of 10 cm/min are desirable conditions to achieve high corrosion protection of 316 L stainless steel in chloride containing environments. Coatings with 3 times exhibit better resistance against corrosion in 0.5 molar NaCl solutions.... 

    The effect of gas mixture of post-oxidation on structure and corrosion behavior of plasma nitrided AISI 316 stainless steel

    , Article Applied Surface Science ; Volume 283 , 2013 , Pages 584-589 ; 01694332 (ISSN) Karimzadeh, N ; Moghaddam, E. G ; Mirjani, M ; Raeissi, K ; Sharif University of Technology
    In this research, microstructure and corrosion properties of plasma nitriding and post-oxidation treated AISI 316 austenitic stainless steel have been studied. The plasma nitriding treatment was carried out at 450 C for 5 h in a D.C. plasma setup with a gas mixture of 25% N2-75% H2 followed by post-oxidation in gas mixtures of O2/H2: 1/3, 1/5, 1/9 and 1/12 for 30 min. The treated samples were characterized by SEM, XRD and roughness testing. Potentiodynamic and cyclic polarization tests were also employed to evaluate the corrosion resistance of the samples. The results showed that plasma nitriding treatment decreases corrosion resistance of the steel substrate. However, post-oxidizing... 

    Transient liquid phase bonding of 304 stainless steel using a co-based interlayer

    , Article Science and Technology of Welding and Joining ; Volume 22, Issue 8 , 2017 , Pages 666-672 ; 13621718 (ISSN) Sadeghian, M ; Ekrami, A ; Jamshidi, R ; Sharif University of Technology
    Transient liquid phase bonding of AISI 304 austenitic stainless steel was carried out using a Co-based interlayer with 40 μm thickness. The effect of bonding time and solid-state homogenisation time on the microstructure and mechanical properties of samples was investigated. The results showed that isothermal solidification was completed within 30 min at a constant temperature of 1180°C. With increasing homogenisation time, at 1000°C, a more uniform distribution of alloying elements and hardness profile across the joint region was achieved. The average shear strength of homogenised samples was about 72% that of the base metal at the same heat treatment cycle. © 2017 Institute of Materials,... 

    An investigation on the sintering behavior of 316L and 17-4PH stainless steel powders for graded composites

    , Article Materials Science and Engineering A ; Volume 424, Issue 1-2 , 2006 , Pages 282-289 ; 09215093 (ISSN) Simchi, A ; Rota, A ; Imgrund, P ; Sharif University of Technology
    This paper presents the densification and microstructure of bilayer structures made from 316L and 17-4PH stainless steels powders during sintering. The requirements for such objects could be magnetic properties at one area of the part and non-magnetic properties at another area of the object. A pressureless solid state sintering method in conjunction with a powder layering technique was used. The sintering was carried out at temperatures ranging from 1100 to 1340 °C for 120 min in hydrogen and vacuum atmospheres. Non-isothermal sintering behavior was also examined by dilatometric analysis. It was found that the strain rate of 17-4PH stainless steel powder is higher than that of 316L during... 

    Effective parameters modeling in compression of an austenitic stainless steel using artificial neural network

    , Article Computational Materials Science ; Volume 34, Issue 4 , 2005 , Pages 335-341 ; 09270256 (ISSN) Bahrami, A ; Mousavi Anijdan, S. H ; Madaah Hosseini, H. R ; Shafyei, A ; Narimani, R ; Sharif University of Technology
    In this study, the prediction of flow stress in 304 stainless steel using artificial neural networks (ANN) has been investigated. Experimental data earlier deduced-by [S. Venugopal et al., Optimization of cold and warm workability in 304 stainless steel using instability maps, Metall. Trans. A 27A (1996) 126-199]-were collected to obtain training and test data. Temperature, strain-rate and strain were used as input layer, while the output was flow stress. The back propagation learning algorithm with three different variants and logistic sigmoid transfer function were used in the network. The results of this investigation shows that the R2 values for the test and training data set are about... 

    Bioglass Coating on 316L Stainless Steel

    , M.Sc. Thesis Sharif University of Technology Pourhashem, Sepideh (Author) ; Afshar, Abdollah (Supervisor)
    Bioactive glasses are able to bond to soft and hard tissues in living body and their application as coating on metallic implants like 316L stainless steel has two important effects: (1) intimate link between bone and materials and (2) corrosion protection of metallic implant in body fluid and protection from tissues in front of corrosion products. Therefore, in this research, 45S5 bioactive glass prepared via sol- gel method was dip coated on 316L stainless steel substrates and its characteristics was investigated.Results of phase analysis showed that by sintering 45S5 bioglass at 600 ˚C for 5 h, an amorph sample with small amount of Na2Ca2Si3O9 was obtained. So, the bioglass coated samples... 

    An Investigation on Pitting Corrosion of 304, 316 and 316L Stainless Steels in 3.5%NaCl Solution and Effect of polyethyleneimine on Pitting Corrosion of These Steels

    , M.Sc. Thesis Sharif University of Technology Kazazi, Mahdi (Author) ; Afshar, Abdollah (Supervisor)
    In this study, pitting corrosion of 304, 316 and 316L stainless steels in 3.5% NaCl solution at different temperatures (25, 40, and 70°C), were studied by electrochemical methods such as Cyclic Potentiodynamic Polarization, Electrochemical Impedance Spectroscopy and Immersion tests. Also, the effects of different concentrations of polyethyleneimine with two molecular weights (2000 and 60000 g/mol) on pitting corrosion of these steels were investigated. Finally, the adsorption behavior of inhibitors on surface of alloys was investigated by Atomic Force Microscopy (AFM) and Attenuated Total Reflectance Fourier transform spectroscopy (ATR-FTIR). It was found that both inhibitors prevent... 

    Correlation between Microstructure with Wear and Toughness Properties of Martensitic Stainless Steel

    , M.Sc. Thesis Sharif University of Technology Khaghani, Alireza (Author) ; Pouranvari, Majid (Supervisor) ; Kokabi, Amir Hossein (Supervisor)
    Fe-Cr-C hardfacing alloy is the most popular alloy used in severe abrasive condition such as mining and cement industries. One of the limitation of these hardfacing alloys is their low toghness, which reduce the application of these alloys under impact wear conditions. The purpose of this thesis is to investigate the effect of microstructure on the wear and toughness properties of AISI420 hardfaced martensitic stainless steel alloy. For this purpose, after deposition of the hardfaced alloy on a steel substrate, various heat treatments such as quench, quench temper, quench and partitioning and austenite reversion are designed to change the microstructure of the hardfaced alloy from fully... 

    Analysis and characterization of the role of NI interlayer in the friction welding of titanium and 304 austenitic stainless steel

    , Article Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science ; 2015 ; 10735623 (ISSN) Muralimohan, C. H ; Ashfaq, M ; Ashiri, R ; Muthupandi, V ; Sivaprasad, K ; Sharif University of Technology
    Springer Boston  2015
    Joining of commercially pure Ti to 304 stainless steel by fusion welding processes possesses problems due to the formation of brittle intermetallic compounds in the weld metal, which degrade the mechanical properties of the joints. Solid-state welding processes are contemplated to overcome these problems. However, intermetallic compounds are likely to form even in Ti-SS joints produced with solid-state welding processes such as friction welding process. Therefore, interlayers are employed to prevent the direct contact between two base metals and thereby mainly to suppress the formation of brittle Ti-Fe intermetallic compounds. In the present study, friction-welded joints between commercially... 

    Welding metallurgy of dissimilar AISI 430/DQSK steels resistance spot welds

    , Article Welding Journal ; Volume 94, Issue 6 , 2015 , Pages 203s-210s ; 00432296 (ISSN) Pouranvari, M ; Marashi, S. P. H ; Alizadeh Sh, M ; Sharif University of Technology
    American Welding Society  2015
    This paper addresses the microstructure and mechanical performance of dissimilar resistance spot welds between AISI 430 ferritic stainless steel and drawing quality special killed (DQSK) low-carbon steel. The mechanical properties of the welds are described by peak load, failure energy, and failure mode during the tensile-shear test. Phase transformations in the fusion zone (FZ) and heat-affected zone (HAZ) are analyzed. The main metallurgical features of the weldment are the formation of a dual-phase, ferrite-martensite microstructure in the FZ, grain growth and martensite formation in the HAZ of the ferritic stainless steel side, and martensitic and eutectoid transformations in the HAZ of... 

    Oxidation behavior of AISI 321, AISI 316, and AISI 409 stainless steels: Kinetic, thermodynamic, and diffusion studies

    , Article Journal of Materials Research ; 2016 , Pages 1-9 ; 08842914 Movahedi Rad, A ; Pelaseyed, S.S ; Attarian, M ; Shokrallahzadeh, R ; Sharif University of Technology
    Cambridge University Press  2016
    The oxidation behavior of three types of stainless steels, namely AISI 321, AISI 316, and AISI 409, was compared. In all stainless steels, oxide layers were formed and their masses and thicknesses increased with oxidation time. Among them, AISI 409 ferritic stainless steel demonstrated higher oxidation rate. According to the kinetical oxidation behavior of them at elevated temperatures, the oxidation mechanism was determined. Among them, the AISI 409 ferritic stainless steel showed the lowest and AISI 321 austenitic stainless steel demonstrated the highest oxidation resistance. Based on the experimental results, it was suggested that the kinetic of oxide growth in stainless steels was... 

    Simulation of recrystallization and martensite revision in 304L austenitic stainless steel after multi-pass rolling processes

    , Article Multiscale and Multidisciplinary Modeling, Experiments and Design ; Volume 3, Issue 4 , 2020 , Pages 227-244 Alavi, P ; Serajzadeh, S ; Sharif University of Technology
    Springer Science and Business Media B.V  2020
    In this work, non-isothermal annealing of cold-rolled 304L austenitic stainless steel was studied at temperatures ranging between 400 and 800 °C. In the first place, a dual-phase structure containing work-hardened austenite and strain-induced martensite was produced by means of multi-pass plate rolling, and then, the deformed steel was subjected to annealing heat treatments. To determine the distribution of stored strain energy in the rolling operations, an elastic–plastic finite-element modeling was conducted. Afterwards, an artificial neural network technique was coupled with the thermal-cellular automata model for prediction of martensite reversion, temperature history, and... 

    An investigation of the densification and microstructural evolution of M2/316L stepwise graded composite during co-sintering

    , Article Journal of Materials Science ; Volume 43, Issue 1 , 2008 , Pages 55-63 ; 00222461 (ISSN) Firouzdor, V ; Simchi, A ; Kokabi, A. H ; Sharif University of Technology
    The densification and microstructural evolution during co-sintering of M2 tool steel/316L stainless steel composite layers with and without boron addition was studied. A pressureless sintering method in conjunction with a powder layering technique was used to fabricate the stepwise graded composite layers. Isothermal and non-isothermal sintering response of the individual and composite layers was examined and the microstructural features of the bonding zone were studied. Shear strength and microhardness of the bonding zone were also measured. It was shown that an enhanced densification is obtained in the composite layers due to (i) sintering shrinkage incompatibility between two steels, (ii)... 

    Using genetic algorithm in heat treatment optimization of 17-4PH stainless steel

    , Article Materials and Design ; Volume 28, Issue 7 , 2007 , Pages 2034-2039 ; 02613069 (ISSN) Zakeri, M ; Bahrami, A ; Mousavi Anijdan, S. H ; Sharif University of Technology
    Elsevier Ltd  2007
    In this investigation heat treatment optimization of 17-4PH stainless steel has been carried out by a genetic algorithm. The optimum technique of heat treatment, adaptive to 17-4PH stainless steel, was obtained from the initial data set by the use of genetic algorithms based on modeling with artificial neural network. The results strongly indicate that the presented model has the great ability for heat treatment optimization of 17-4PH stainless steel to yield the highest strength levels in different working temperatures. © 2006 Elsevier Ltd. All rights reserved  

    Seismic performance of stainless-steel built-up box columns subjected to constant axial loads and cyclic lateral deformations

    , Article Structures ; Volume 33 , 2021 , Pages 4080-4095 ; 23520124 (ISSN) Moghaddam, H ; Sadrara, A ; Jalali, S. R ; Sharif University of Technology
    Elsevier Ltd  2021
    The seismic behavior of stainless-steel built-up box columns subjected to constant axial loads and cyclic lateral deformation that are used in special moment frames (SMFs) has been investigated through finite element (FE) analysis. A total of 208 numerical models were conducted to cover a range of parameters affecting the seismic behavior of the columns. These include the web slenderness ratio, flange slenderness ratio, global slenderness ratio, axial load level, and lateral loading protocol. The performance indices of overstrength factor, axial shortening, out-of-plane deformation, plastic hinge length, and rotation capacity were calculated and compared. Local buckling of the columns also... 

    Investigation of spring back phenomenon in the 316L stainless steel cathode blank based on the changes in electrical resistivity and magnetic properties due to the residual stress and martensite phase formation: An industrial failure

    , Article Engineering Failure Analysis ; Volume 126 , 2021 ; 13506307 (ISSN) Shojaei, M ; Khayati, G. R ; Hosseini por, H ; Khorasani, S. M. J ; Kafi Hernashki, R ; Sharif University of Technology
    Elsevier Ltd  2021
    316L stainless steel is widely used as cathode blank in copper electrorefining. These cathode blanks become distorted through the cathode stripping in the cathode stripping machine and must be straightened before using again. After several times repeated cold straightening, the cathode blank spring backs to its distorted position during electrorefining resulted in short circuits and current efficiency decreases. The objectives of this study were to: i) investigate the cathode blank spring back behavior and properties; ii) propose a solution adhere to the subject. To achieve these goals, more than 20 samples are selected and cut into small pieces to simulate the cold straightening process.... 

    Manufacture, Mechanical Properties and Interfacial Corrosion of 316L/17-4PH Bimetals with a Nanostructured Ni Layer

    , M.Sc. Thesis Sharif University of Technology Salahi, Armita (Author) ; Simchi, Abdol Reza (Supervisor) ; Dolati, Abol Ghasem (Supervisor)
    Transient liquid phase (TLP) bonding of 316L/17-4PH bimetals using a thin layer of nanostructured nickel was studied. The nanostructured nickel interface was deposited through pulse current coating in a Watt bath. The TLP bonding was performed at different temperatures ranging from 1000 °C to 1300 °C using a nickel interface having different thicknesses (2-17µm) and crystallite size (14-67 nm). The microstructure of the joint bimetals and phase formation were studied using the optical and scanning electron microscopes and X-ray diffraction (XRD) method. The mechanical properties of the bimetals were evaluated by micro-hardness and shear tests. To evaluate the corrosion behavior of the... 

    Investigation on Formability of Two-layered Stainless Steel-copper Sheets with FLDs

    , M.Sc. Thesis Sharif University of Technology Tavousi Masrour, Sina (Author) ;
    In this research, two-layered sheets of copper and stainless steel 316 were produced by roll bonding. These sheets provide a combination of properties of copper and stainless steel; including high strength, thermal conductivity and corrosion resistance, as well as low weight and cost-efficient means of production. The effects of thickness reduction, different preheat temperatures and varying heating conditions after rolling on bond strength were studied. In some specimens, an aluminum sheet was used as a middle-layer, which significantly improved the bonding quality. In order to observe the interface of the bonded specimens, optical microscope images of the cross sections were studied....