En
  • دکتری (1370)

    مهندسی تکنولوژی جوشکاری

    کرانفیلد، انگلستان

  • کارشناسی‌ارشد (1366)

    مهندسی تکنولوژی جوشکاری

    کرانفیلد، انگلستان

  • کارشناسی (1359)

    مهندسی مکانیک

    دانشکده نفت آبادان، ایران

  • بازرسی فنی
  • جوشکاری
  • آزمایشگاه متالوگرافی

    زمینه های پژوهشی:

    کارشناس مسئول:

    تلفن:

    مکان: تهران-جلال آل احمد-پل نصر-دانشگاه تربیت مدرس

  • کارگاه 4-10

    زمینه های پژوهشی:

    کارشناس مسئول:

    تلفن:

    مکان: بلوک 4 طبقه 2- اتاق4-10

داده ای یافت نشد

ارتباط

رزومه

Microstructural characteristics of fusion zone in continuous wave fiber laser welded Nb-modified δ-TRIP steel

Y Najafi, FM Ghaini, Y Palizdar, SG Shiri, M Pakniat
Journal Papers , , {Pages }

Abstract

Criterion for predicting expulsion in resistance spot welding of steel sheets

Moslem Valaee-Tale, Mohsen Sheikhi, Yousef Mazaheri, Farshid Malek Ghaini, Gholam Reza Usefifar
Journal PapersJournal of Materials Processing Technology , Volume 275 , 2020 January 1, {Pages 116329 }

Abstract

Resistance spot welding (RSW) is frequently accompanied by expulsion, an undesirable event taking place in manufacturing processes, including car body production. Many variables are involved in RSW, all of which can affect expulsion. This investigation aimed at developing an analytical model for predicting expulsion in RSW. Accordingly, based on force and moment balances, a criterion was established. It was proposed that expulsion took place when the molten metal ejected as a result of the pressure inside nugget. The model presented here considered that the pressure inside the nugget was mainly due to melting transformation and liquid thermal expansion. Hence, the model took into account the effects of nugget diameter, electrode force, base

Surface transformation hardening of ductile cast iron by a 600w fiber laser

F Malek Ghaini, MH Ameri, MJ Torkamany
Journal PapersOptik , Volume 203 , 2020 February 1, {Pages 163758 }

Abstract

Laser transformation surface hardening of the forming edges of large mold made of nodular cast iron has gained momentum in recent years. In this investigation a 600 w fiber laser was employed to harden GGG-60 cast iron. It is found that to achieve the optimum surface properties, the combination of laser power density and travel speed has to be set such that to dissolve the carbides but not that high to dissolve the graphite nodules. The response of a hardened track to a second thermal cycle by a neighboring laser track in terms of both tempering and re-hardening showed that by increasing the overlapping, a more uniform surface microstructure and hardness is obtained. In addition by employing differential scanning calorimetry (DSC) analysi

Damage mechanisms in the ultra-low cycle fatigue loading

M Kermajani, F Malek Ghaini, R Miresmaeili, MK Baghi-abadi, M Mousavi-nasab
Journal PapersEngineering Fracture Mechanics , Volume 223 , 2020 January 1, {Pages 106772 }

Abstract

Predicting extreme limit states in steel structures using finite element simulations requires an understanding of the fracture mechanisms themselves and the relationship of various models to these mechanisms. Aiming at addressing dominant damage mechanisms in the Ultra-Low-Cycle Fatigue (ULCF) regime which occurs during earthquakes, circumferentially notched tensile bars were subjected to cyclic loadings with large displacement amplitudes. Two weld metals from rutile and basic classifications and two different grades of structural steels were selected to determine the role of microstructural features in the response of materials to ULCF conditions. Scanning Electron Microscopy (SEM) technique equipped with 3D measurement software was employ

The relation between magnesium evaporation and laser absorption and weld penetration in pulsed laser welding of aluminum alloys: Experimental and numerical investigations

Zeinab Malekshahi Beiranvand, Farshid Malek Ghaini, Homam Naffakh Moosavy, Mohsen Sheikhi, Mohammad Javad Torkamany, Mahmoud Moradi
Journal PapersOptics & Laser Technology , Volume 128 , 2020 August 1, {Pages 106170 }

Abstract

It is observed that in laser welding of aluminum alloys, magnesium can evaporate, and the weld penetration is dependent on Mg content of the alloy and Mg loss from the weld pool. In this research, it is proposed that the presence of Mg not in the base metal alloy, but rather the presence of Mg vapor in the plasma plume over the weld pool affects the laser absorption, and it is through this phenomenon that the weld profile and penetration is affected. Numerical simulation was performed to determine the relationship between the weld profile to estimate the effective laser absorption coefficient of four Al alloys and in parallel EPMA technique was used to determine the Mg losses of the weld metals. The combined analysis of the results showed t

Biocompatibility assessments of 316L stainless steel substrates coated by Fe-based bulk metallic glass through electro-spark deposition method

Afsaneh Esmaeili, Seyed Amir Ghaffari, Maryam Nikkhah, Farshid Malek Ghaini, Farhad Farzan, Soheila Mohammadi
Journal PapersColloids and Surfaces B: Biointerfaces , 2020 November 16, {Pages 111469 }

Abstract

Metallic materials made of rather precious alloys are widely used in orthopedic surgery, circulatory system, and dentistry fields. Stainless steel coated by alloys with a variety of physiochemical properties can be an excellent candidate for making economical devices with superior biomedical compatibility. In this study, a Fe- based metallic glass alloy was applied on 316L stainless steel (316L SS) using the electro-spark deposition (ESD) method as an economic and easy handling method. The coated samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and atomic force microscopy (AFM). It was found that a metallic glass coating was uniformly formed on the stainless steel substrate. Cytocompatibility (MTT a

Numerical and experimental investigation of current and electrode force effects on expulsion in resistance spot welding of galvanized and non-galvanized steel sheets

Moslem Valaee Tale, Yousef Mazaheri, Mohsen Sheikhi, Farshid Malek Ghaini, Gh R Usefifar
Journal PapersModares Mechanical Engineering , Volume 19 , Issue 7, 2019 July 15, {Pages 1797-1804 }

Abstract

During the process of Resistance spot welding (RSW), some of the molten metal comes out of the interface of the two sheets, which causes contamination on the body of the cars. This named as expulsion and disrupts the staining process and reduces the safety of the workshop. In this study, by numerical and Experimental investigation, effect of welding current and electrode force on expulsion in RSW of galvanized and non-galvanized steel sheets the prediction of expulsion for both sheets was performed. Experimental results showed that with increasing the welding current, nugget diameter and weld strength increased continuously until expulsion occurrence. The resultant nugget in both types of sheets have almost similar diameter at the similar w

An Analytical Model for Prediction of Solidification Cracking Susceptibility in Aluminum Alloys Taking into Account the Effect of Solidification Rate

Zeinab Malekshahi Beiranvand, Farshid Malek Ghaini, Homam Naffakh Moosavy, Mohsen Sheikhi, Mohammad Javad Torkamany
Journal PapersMetallurgical and Materials Transactions A , Volume 50 , Issue 6, 2019 June 15, {Pages 2835-2846 }

Abstract

Solidification cracking in pulsed laser welding of aluminum alloys has been the subject of a number of researches. The purpose of this study is to analyze the possible effects of high solidification rates involved in pulsed laser welding on the solidification path of aluminum alloys and solidification cracking sensitivity. For the analysis, conditions at the interface are not necessarily considered to be at equilibrium. Accordingly, the solidification path is modified taking into account the effects of solidification rate on the solidus, liquidus, and eutectic temperatures, the liquidus slope, and the interface parameters, including the partition coefficient, the cell/dendrite tip radius, and the liquid composition in the cellu

Intercritical and subcritical spheroidization of 10B38 cold heading steel

Ata Radnia, Farshid Malek Ghaini, Reza Miresmaeili
Journal PapersMaterials Research Express , 2019 June 12, {Pages }

Abstract

For the production of bolts by cold forging, the hardenable steel has to be in a soft and ductile state. The Cold Heading Quality Steel is achievable by a spherodization heat treatment on the hot rolled material. The scope of this study is a boron bearing medium carbon steel which has many promising properties as bolting material. The experimentations covers two different initial conditions before the spheroidization heat treatment: hot rolled and quenched. Two spheroidization procedures are also considered: subcritical and intercritical heat treatments. To assess the cold formability, a special notched tensile test is employed and the results are supported with metallographic and hardness measurements. For both subcritical and intercritica

Solidification cracking susceptibility in pulsed laser welding of Al–Mg alloys

Z Malekshahi Beiranvand, F Malek Ghaini, H Naffakh Moosavy, M Sheikhi, MJ Torkamany
Journal PapersMaterialia , Volume 7 , 2019 September 1, {Pages 100417 }

Abstract

Prevention of solidification cracking is a major concern in pulsed laser welding of aluminum–magnesium alloys. Laser parameters can affect both Mg evaporation and the solidification rate. In this study the interactive effects of Mg evaporation and solidification rate on solidification cracking susceptibility (SCS) is investigated. It is shown that due to the rapid solidification of Al–Mg alloys in pulsed laser welding, SCS increases and the maximum cracking susceptibility occurs at alloy with higher Mg composition in comparison to a casting process. Hence, the range of the composition susceptible to solidification cracking is expanded. The calculations on Al–Mg alloy 5083 showed that when the laser pulse frequency is increased, SCS is

Investigation into the efficiency of a fiber laser in surface hardening of ICD-5 tool steel

MH Ameri, F Malek Ghaini, MJ Torkamany
Journal PapersOptics & Laser Technology , Volume 107 , 2018 November 1, {Pages 150-157 }

Abstract

Surface transformation hardening is a vital final step in the manufacture of stamping and forming dies. An important requirement for the hardening process is minimizing the injection of heat into the precision machined component. The objective of this study is to find the parameters that govern the efficiency of utilizing a 500 W fiber laser for hardening of ICD-5 tool steel. It is shown that the heating part of the thermal cycle and complete dissolution of carbides in austenite has the controlling effect on the resultant microstructure and hardness. The surface hardness can be affected by as much as 100 HVN with increase in the power density or decrease in the travel speed. Hardening efficiency index (HEI) is defined for describing the e

Characterization of Fe49Cr18Mo7B16C4Nb6 high-entropy hardfacing layers produced by gas tungsten arc welding (GTAW) process

Hossein Abed, Farshid Malek Ghaini, Hamid Reza Shahverdi
Journal PapersSurface and Coatings Technology , Volume 352 , 2018 October 25, {Pages 360-369 }

Abstract

An iron based glassy alloy with the nominal stoichiometry of Fe49Cr18Mo7B16C4Nb6 was deposited on a carbon steel substrate by gas tungsten arc welding (GTAW) process. Effects of the number of weld layers and weld heat input were studied. Optical microscope (OM), scanning electron microscope (FE_SEM) and X-ray diffraction analysis (XRD) were used to characterize the microstructure and phase distribution. Hardness and wear behavior of the deposited layers were also investigated. The results showed that a multi-phase structure consisting of hard boride (Mo2FeB2) and nano-sized carbide (NbC) phases were formed in a nanostructured α-Fe matrix. The ratio of hard phases and subsequently hardness of layers were increased by increasing the number o

Magnesium Loss in Nd: YAG Pulsed Laser Welding of Aluminum Alloys

Z Malekshahi Beiranvand, F Malek Ghaini, H Naffakh-Moosavy, M Sheikhi, MJ Torkamany
Journal PapersMetallurgical and Materials Transactions B , Volume 49 , Issue 5, 2018 October 1, {Pages 2896-2905 }

Abstract

In the current investigation, the loss of magnesium (Mg) in Nd:YAG pulsed laser welding of a number of aluminum (Al) alloys was studied both experimentally and numerically. The experimental results showed that at a fixed average laser power, with the increasing pulse frequency, Mg concentration of the weld metals decreased. A numerical model was developed for the calculation of Mg evaporation from the weld pool. The model predicted a trend in the changes of Mg concentration of the weld pool, working best for alloys containing the higher levels of Mg. The calculations showed that with the increasing pulse frequency from 15 to 40?Hz, due to a decrease in the average temperature of the weld pool, Mg loss in terms of mass per uni

The effect of electrospark nickel interlayer thickness on the characteristics of Niobium to 410 stainless steel dissimilar laser welding

Seyed Hamzeh Baghjari, Farshid Malek Ghaini, Barbara Previtali, Ali Gokhan Demir, Hamid Reza Shahverdi, Carlo Mapelli, Silvia Barella
Journal PapersJournal of Manufacturing Processes , Volume 30 , 2017 December 1, {Pages 51-62 }

Abstract

Dissimilar welding of Niobium to 410 stainless steel has important engineering applications. An interlayer should be used for avoiding or reducing formation of brittle intermetallic phases in weld. In this research the effect of gradual addition of ESD interlayer on the chemical composition, microstructure and mechanical properties of Nb to 410 stainless steel dissimilar laser welding is investigated. The Nb plate with the ESD interlayer thickness equivalent to about 25%, 50%, and 100% of base plate thicknesses on its edge (produced by novel electrospark deposition process) was laser welded to 410 stainless steel by pulsed Nd:YAG laser. The welds were then subjected to metallographic, X-ray diffraction and mechanical tests. Results showed t

Effect of heat treatment on liquation cracking in continuous fiber and pulsed Nd: YAG laser welding of hastelloy X alloy

M Pakniat, F Malek Ghaini, MJ Torkamany
Journal PapersMetallurgical and Materials Transactions A , Volume 48 , Issue 11, 2017 November 1, {Pages 5387-5395 }

Abstract

Laser welding of HASTELLOY X is highly feasible; however, hot cracking can be a matter of concern. The objective of this study is to assess the effect of solution heat treatment on susceptibility to liquation cracking in welding of a 2-mm-thick HASTELLOY X plate. In addition, Nd-YAG pulsed laser (400?W) and continuous wave (CW) fiber laser (600?W) were compared with each other in this respect. Results revealed that performing the prewelding solution heat treatment reduces the tendency for occurrence of liquation cracking. Furthermore, it was established that by increasing pulse frequency, there was a significant reduction in the tendency for liquation cracking. With CW laser welding of HASTELLOY X in the solution-heat-treated

A new procedure for refurbishment of power plant Superalloy 617 by pulsed Nd: YAG laser process

Naser Taheri, Homam Naffakh-Moosavy, Farshid Malek Ghaini
Journal PapersOptics & Laser Technology , Volume 91 , 2017 June 1, {Pages 71-79 }

Abstract

The present study has evaluated the surface rejuvenation of aged Inconel 617 superalloy by both GTAW and pulsed Nd:YAG laser techniques. The gas tungsten arc welding (GTAW) by heat input per unit length [Q/V(J/mm)] of 280, 291.67, 309.74 and 225.48 (J/mm), and the pulse Nd:YAG laser process by the 15.71, 19.43 and 22.32 (J/mm), were employed. The Rosenthal equation was used for calculation of mushy zone (MZ) and partially-melted zone (PMZ). Size of MZ and PMZ in GTAW are more than 31 and 6 times than that of formed in pulsed Nd:YAG laser. According to the characterizations, solidification and liquation cracks were observed in these areas produced by GTAW whereas no cracks were identified in laser treated samples. Also, line scan EDS analyse

An insight to the mechanism of weld penetration in dissimilar pulsed laser welding of niobium and Ti–6Al–4V

MJ Torkamany, F Malek Ghaini, R Poursalehi
Journal PapersOptics & Laser Technology , Volume 79 , 2016 May 1, {Pages 100-107 }

Abstract

In laser welding of Ti–6Al–4V to niobium, the interaction of laser with the two metals is such that at the investigated laser conditions there will be conduction mode on the Nb side and keyhole on the Ti side. Thus the weld pool is not developed symmetrically as there will not be sufficient penetration in the higher melting point higher conductivity niobium side. The mechanisms of energy absorption and effective melting in dissimilar laser welding are analyzed. It is shown that more penetration into niobium is obtained when the laser energy is absorbed by Ti–6Al–4V and then the molten Ti–6Al–4V dissolves the niobium metal.

Hot cracking in laser welding of Hastelloy X with pulsed Nd: YAG and continuous wave fiber lasers

M Pakniat, F Malek Ghaini, MJ Torkamany
Journal PapersMaterials & Design , Volume 106 , 2016 September 15, {Pages 177-183 }

Abstract

Hastelloy X is a corrosion and heat resistance solution hardened nickel base super alloy. This alloy having an austenitic microstructure and in this regard is expected to be prone to hot cracking in fusion welding. In this research a 400?W Nd:YAG pulsed laser and 600?W continuous wave fiber laser welding are employed to weld a 2?mm thick Hastelloy X plates. Comparison is made with regard to weld penetration and tendency of occurrence of solidification cracking in the weld metal and liquation cracks in the heat affected zone. It is found that with pulsed laser hot cracks are formed, however, with continuous wave laser hot cracking can be avoided. Increasing the laser pulse frequency and pulse duration resulted in a significant reduction in h

Characteristics of electrospark deposition of a nickel-based alloy on 410 stainless steel for purpose of facilitating dissimilar metal welding by laser

Seyed Hamzeh Baghjari, Farshid Malek Ghaini, Hamid Reza Shahverdi, Mohammad Ebrahimnia, Carlo Mapelli, Silvia Barella
Journal PapersThe International Journal of Advanced Manufacturing Technology , Volume 87 , Issue 12-Sep, 2016 December 1, {Pages 2821-2828 }

Abstract

In this research, a new method is developed using the electrospark deposition (ESD) process for making an interlayer, which could be useful in welding dissimilar metals. Alloy 82 nickel-based alloy was deposited on the edge of a 410-stainless-steel plate and used as an interlayer for subsequent welding to a nickel Alloy 82 plate forming a dissimilar metal weld. Metallographic analysis showed that the ESD layer consisted of a γ phase, columnar grains oriented in {100} direction and cellular solidification morphology with 250–350?nm cell diameter. Neither Lave phase nor large carbide crystals were observed in the microstructure of ESD layer due to the high-cooling rate and the low tendency for segregation. Tensile test exhib

Dynamic recrystallization phenomena during laser-assisted friction stir processing of a precipitation hardened nickel base superalloy

SM Mousavizade, M Pouranvari, F Malek Ghaini, H Fujii, YF Sun
Journal PapersJournal of Alloys and Compounds , Volume 685 , 2016 November 15, {Pages 806-811 }

Abstract

Laser-assisted friction stir processing was used to modify the microstructure of an as-cast gamma prime strengthened nickel base superalloy. The grain structure of top region of the stir zone, where full dissolution of gamma prime precipitates occurred during heating, is controlled by discontinuous dynamic recrystallization mechanism and the pinning effect of refined carbides and cooling gamma prime precipitates. In the bottom of the stir zone, the partial dissolved gamma prime precipitates play important role in grain structure development by their pinning effect in retarding grain growth during cooling as well as by a continuous recrystallization mechanism.

دروس نیمسال جاری

  • كارشناسي ارشد
    بازرسي تجهيزات صنعت نفت و گاز ( واحد)
    دانشکده فنی و مهندسی، گروه شناسايي وانتخاب مواد
  • كارشناسي ارشد
    بازرسي و كنترل كيفي جوش ( واحد)

دروس نیمسال قبل

  • دكتري
    روش هاي پيشرفته غير مخرب ( واحد)
    دانشکده فنی و مهندسی، گروه خوردگي و حفاظت از فلزات
  • 1397
    كرمي, حسين
    مقايسه جوشپذيري ميلگردهاي فولادي مطابق با استاندارد ايران در توليد تيرچه خرپايي سقف هاي تيرچه بلوك به روشهاي جوشكاري مقاومتي الكتريكي، GMAW ( گاز محافظ CO2) و SMAW
  • 1398
    ماهي كار, هادي
  • 1398
    بزرگ زاده, مسعود
  • 1398
    ديانتي, محمدرضا
  • دبیر شورای نظارت وارزیابی دانشکده فنی و مهندسی
  • رئیس بخش مهندسی مواد
  • عضو کارگروه بررسی صلاحیت علمی دانشکده فنی و مهندسی - گروه شناسایی و انتخاب مواد
  • مدیر گروه شناسایی و انتخاب مواد
  • رئیس بخش مهندسی مواد دانشکده فنی و مهندسی
    داده ای یافت نشد

مهم

جدید

    اطلاعیه ای درج نشده است