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  • 1.
    Forouzan, Farnoosh
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Gunasekaran, Suresh
    Department for Materials Science, Functional Materials, Saarland University.
    Hedayati, Ali
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Vuorinen, Esa
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Mücklich, Frank
    Department for Materials Science, Functional Materials, Saarland University.
    Microstructure analysis and mechanical properties of Low alloy High strength Quenched and Partitioned Steel2016Ingår i: MSMF 2016: Materials Structure & Micromechanics of Fracture, 2016Konferensbidrag (Refereegranskat)
  • 2.
    Forouzan, Farnoosh
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Gunasekaran, Suresh
    Hedayati, Ali
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Vuorinen, Esa
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Mücklich, Frank
    Department for Materials Science, Functional Materials, Saarland University, D-66041 Saarbrücken, Germany.
    Microstructure analysis and mechanical properties of Low alloy High strength Quenched and Partitioned Steel2017Ingår i: Solid State Phenomena, ISSN 1012-0394, E-ISSN 1662-9779, Vol. 258, s. 574-578Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Gleeble study of the quenching and partitioning (Q&P) process has been performed onDomex 960 steel (Fe, 0.08 %C, 1.79 %Mn, 0.23 %Si, 0.184 %Ti, and 0.038 %Al). The effect ofdifferent Q&P conditions on microstructure and mechanical properties were investigated. The aimof the process is to produce a fine grained microstructure for better ductility and controlled amountsof different micro-constituents to increase the strength and toughness simultaneously. Threedifferent quenching temperatures, three partitioning temperatures and three partitioning times havebeen selected to process the 27 specimens by Gleeble® 1500. The specimens were characterized bymeans of OM, SEM, XRD, hardness and impact tests. It was found that, fine lath martensite withretained austenite is achievable without high amount of Si or Al in the composition although lack ofthese elements may cause the formation of carbides and decrease the available amount of carbon forpartitioning into the austenite. The hardness increases as the quenching temperature is decreased,however, at highest partitioning temperature (640◦C) the hardness increases sharply due to extensiveprecipitate formation.

  • 3.
    Forouzan, Farnoosh
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Kermanpur, Ahmad
    Department of Materials Engineering, Isfahan University of Technology.
    Najafizadeh, Abbas
    Department of Materials Engineering, Isfahan University of Technology.
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    Processing of Nano/Submicron Grained Stainless Steel 304L by an Advanced Thermomechanical Process2009Konferensbidrag (Refereegranskat)
  • 4.
    Forouzan, Farnoosh
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Kermanpur, Ahmad
    Department of Materials Engineering, Isfahan University of Technology.
    Najafizadeh, Abbas
    Department of Materials Engineering, Isfahan University of Technology.
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    Processing of Nano/Submicron Grained Stainless Steel 304L by an Advanced Thermomechanical Process2012Ingår i: International Journal of Modern Physics, Conference Series, ISSN 2010-1945, Vol. 5, s. 383-390Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Nano/Submicron crystalline grains of about 250 nm were obtained in a metastable austenitic stainless steel AISI304L by an advanced thermomechanical process consisting of heavy conventional cold rolling and annealing. Effects of cold thickness reduction and temperature and time of the reversion treatment on microstructure and mechanical properties of the steel were investigated. The nano-structured austenitic steel exhibited not only high strength (above 1 GPa) but also good elongation (above 50%).

  • 5.
    Forouzan, Farnoosh
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Najafizadeh, Abbas
    Department of Materials Engineering, Isfahan University of Technology.
    Kermanpur, Ahmad
    Department of Materials Engineering, Isfahan University of Technology.
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    Artificial neural network models for production of nano-grained structure in AISI 304L stainless steel by predicting thermo-mechanical parameters2009Ingår i: International Journal of Iron & Steel Society, Vol. 6, nr 2, s. 6-13Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    An artificial neural network (ANN) model is developed for the analysis, simulation, and prediction of the austenite reversion in the thermo-mechanical treatment of 304L austenitic stainless steel. The results of the ANN model are in good agreement with the experimental data. The model is used to predict an appropriate annealing condition for austenite reversion through the martensite to austenite transformation. This model can also be used as a guide for further grain refining and to improve mechanical properties of the AISI 304L stainless steel.

  • 6.
    Forouzan, Farnoosh
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Najafizadeh, Abbas
    Department of Materials Engineering, Isfahan University of Technology.
    Kermanpur, Ahmad
    Department of Materials Engineering, Isfahan University of Technology.
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    Optimization of the Thermomechanical Parameters to AISI 304L Stainless Steel using Neural Network2009Ingår i: International Journal of Iron & Steel Society of Iran, Vol. 6Artikel i tidskrift (Refereegranskat)
  • 7.
    Forouzan, Farnoosh
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Najafizadeh, Abbas
    Department of Materials Engineering, Isfahan University of Technology.
    Kermanpur, Ahmad
    Department of Materials Engineering, Isfahan University of Technology.
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    Simulation of mechanical properties and obtaining nano/submicron AISI 304L stainless steel through the martensite reversion process by using naural network2010Konferensbidrag (Refereegranskat)
  • 8.
    Forouzan, Farnoosh
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Najafizadeh, Abbas
    Department of Materials Engineering, Isfahan University of Technology.
    Kermanpur, Ahmad
    Department of Materials Engineering, Isfahan University of Technology.
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    Surkialiabad, Roohallah
    Department of Materials Engineering, Isfahan University of Technology.
    Production of nano/submicron grained AISI 304L stainless steel through the martensite reversion process2010Ingår i: Materials Science & Engineering: A, ISSN 0921-5093, E-ISSN 1873-4936, Vol. 527, nr 27-28, s. 7334-7339Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Production of nano/submicron grained AISI 304L austenitic stainless steel through formation of strain-induced martensite and its reversion to austenite are studied in this paper. The effects of annealing parameters on the microstructural development and mechanical properties are also investigated. Heavily cold rolling at 0 °C is employed to induce the formation of martensite in the metastable austenitic material, followed by reversion treatment at the temperature range of 700-900 °C for 0.5-300. min. Microstructural evolutions are analyzed using Feritscope, X-ray diffraction, and scanning electron microscopy, whereas the mechanical properties are determined by hardness and tensile tests. The smallest grain size (about 135. nm) is obtained in the specimen annealed at 700 °C for 20. min. The resultant nano/submicron grained steel not only exhibits a high strength level (about 1010. MPa) but also a desirable elongation of about 40%. Moreover, an annealing map is developed which indicates the appropriate range of annealing parameters for grain refinement of AISI 304L stainless steel through the martensite reversion process.

  • 9.
    Forouzan, Farnoosh
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Najafizadeh, Abbas
    Department of Materials Engineering, Isfahan University of Technology.
    Kermanpur, Ahmed
    Department of Materials Engineering, Isfahan University of Technology.
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    Simulation of mechanical properties and obtaining nano/submicron AISI 304L stainless steel through the martensite reversion process by using naural network2010Konferensbidrag (Refereegranskat)
  • 10. Forouzan, M. R
    et al.
    Kermanpur, Ahmad
    Department of Materials Engineering, Isfahan University of Technology.
    Forouzan, Farnoosh
    Department of Materials Engineering, Isfahan University of Technology.
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    Jalali, M. R
    Numerical Simulation of Temperature History and Phase Transformations during Submerged Direct Seam Welded Pipes of steel X702009Konferensbidrag (Refereegranskat)
  • 11. Haerian, B
    et al.
    Najafizadeh, Abbas
    Department of Materials Engineering, Isfahan University of Technology.
    Kermanpur, Ahmad
    Department of Materials Engineering, Isfahan University of Technology.
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    The effect of cold deformation: annealing process on grain size of austenitic stainless steel AISI 3042008Konferensbidrag (Refereegranskat)
  • 12.
    Hedayati, Ali
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Asghari, S
    Alinoori, A.
    An Investigation on Corrosion properties and contact resistance of TiN coating on AISI 316L stainless steel as bipolar plate in proton exchange membrane fuel cell2012Konferensbidrag (Refereegranskat)
  • 13.
    Hedayati, Ali
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Department of Materials Engineering, Isfahan University of Technology.
    Asghari, S
    Alinouri, A
    An Investigation on contact resistance and corrosion properties of AISI 316L stainless steel as bipolar plate in proton exchange membrane fuel cell2012Konferensbidrag (Refereegranskat)
  • 14.
    Hedayati, Ali
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Asghari, Saeed
    Institute of Materials and Energy, Iranian Space Research Cente.
    Alinoori, Amir Hosein
    Institute of Materials and Energy, Iranian Space Research Cente.
    Koosha, Morteza
    Institute of Materials and Energy, Iranian Space Research Cente.
    Vuorinen, Esa
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Effects of coating thickness on corrosion and contact resistance behavior of TiN coated AISI 316L as bipolar plates for PEMFC2016Ingår i: Iranian Journal of Hydrogen & Fuel Cell, ISSN 2383-1618, Vol. 3, nr 2, s. 137-149Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the polymer electrolyte membrane fuel cells (PEMFCs), low corrosion resistance and high interfacial contact resistance (ICR) are two controversial issues in usage of AISI 316L stainless steel as a metallic bipolar plate. For solving these problems, investigation and development of different coatings and/or surface treatments are inevitable. Corrosion behavior and ICR of AISI 316L specimens coated with 1, 2, and 3 µm thick TiN were investigated. Potentiodynamic (PD), potentiostatic (PS) and electrochemical impedance spectroscopy (EIS) tests were conducted at 80 °C in pH3 H2SO4+2 ppm HF solution purged with either O2 or H2 under both simulated cathodic and anodic conditions. The PS corrosion test results revealed that the current densities of the specimens were below 1 µA cm−2. In the simulated cathodic condition, an increase of coating thickness from 1 to 3 µm led to a relatively large decrease of the current density from 0.76 to 0.43 µA cm−2. Furthermore, the ICR values of the coated specimens after the PS test were lower than that of the uncoated specimen before the PS. In general, the TiN coating decreases the ICR, and has enough corrosion resistance in simulated PEMFC conditions. However, none of the coatings achieved the DOE ICR targets.

  • 15.
    Hedayati, Ali
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Asghari, Saeed
    Alinouri, Amirhossein
    Corrosion behavior and interfacial contact resistance of TiN coated type 316L stainless steel as bipolar plate for proton exchange membrane fuel cell2013Konferensbidrag (Refereegranskat)
  • 16.
    Hedayati, Ali
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Asghari, Saeed
    Faghilhimmani, Bagher
    Koosha, Morteza
    A coating with highcorrosion resistance and low interfacial contact resistance for metallic bipolar plates of PEMfuel cells2013Patent (Övrig (populärvetenskap, debatt, mm))
  • 17.
    Hedayati, Ali
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Forouzan, Farnoosh
    Department of Materials Engineering, Isfahan University of Technology.
    Najafizadeh, Abbas
    Department of Materials Engineering, Isfahan University of Technology.
    Kermanpur, Ahmad
    Department of Materials Engineering, Isfahan University of Technology.
    An Advanced Thermomechanical Process to Obtain Nano/Submicron Grain Sizes in a Metastable Austenitic Stainless Steel2008Konferensbidrag (Refereegranskat)
  • 18.
    Hedayati, Ali
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Forouzan, Farnoosh
    Department of Materials Engineering, Isfahan University of Technology.
    Najafizadeh, Abbas
    Department of Materials Engineering, Isfahan University of Technology.
    Kermanpur, Ahmad
    Department of Materials Engineering, Isfahan University of Technology.
    Surki Aliabadi, Rouhallah
    Department of Materials Engineering, Isfahan University of Technology.
    The process to produce a new generation of AISI 304L Austenitic Stainless Steelwith High Strength & Good Elongation by the creation of Nano Grain Size Structure2010Patent (Övrig (populärvetenskap, debatt, mm))
  • 19.
    Hedayati, Ali
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap. Department of Materials Engineering, Isfahan University of Technology.
    Forouzan, Farnoosh
    Department of Materials Engineering, Isfahan University of Technology.
    Najafizadeh, Abbas
    Kermanpur, Ahmad
    Department of Materials Engineering, Isfahan University of Technology.
    Surki, R
    Effect of Cold Work Percent on Mechanical Properties of AISI 304L Stainless Steel2009Konferensbidrag (Refereegranskat)
    Abstract [en]

    This article investigates the effect of various degrees of plastic deformation introduced by cold rolling at zero temperature on the mechanical properties of AISI 304L stainless steel. microstructural and ferromagnetic studies were also conducted. The material was evaluated up to 90% reduction in thickness. For this purpose, magnetic measurements, optical metallography, hardness and Tensile test, were used. Results show that by increasing the amount of rolling strain, transformation of austenite to martensite generally increases. The regime of this increase depends on the amount of the plastic deformation and temperature. The tensile strength and hardness were found to increase with the increase of cold rolling percentage (%CR) up to 90%.The results indicate that the formation of strain-induced martensite evidently led to a significant strengthening of the steel.

  • 20.
    Hedayati, Ali
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Najafizadeh, Abbas
    Department of Materials Engineering, Isfahan University of Technology.
    Kermanpur, Ahmad
    Department of Materials Engineering, Isfahan University of Technology.
    Forouzan, Farnoosh
    Department of Materials Engineering, Isfahan University of Technology.
    Submicron Microstructure Achieved by Thermomechanical Process in Metastable Austenitic Stainless Steel AISI 304L2009Konferensbidrag (Refereegranskat)
  • 21.
    Hedayati, Ali
    et al.
    Department of Materials Engineering, Isfahan University of Technology.
    Najafizadeh, Abbas
    Department of Materials Engineering, Isfahan University of Technology.
    Kermanpur, Ahmad
    Department of Materials Engineering, Isfahan University of Technology.
    Forouzan, Farnoosh
    Department of Materials Engineering, Isfahan University of Technology.
    The effect of cold rolling regime on microstructure and mechanical properties of AISI 304L stainless steel2010Ingår i: Journal of Materials Processing Technology, ISSN 0924-0136, E-ISSN 1873-4774, Vol. 210, nr 8, s. 1017-1022Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper, the effect of different thickness reductions by cold rolling on the microstructure and mechanical properties of AISI 304L austenitic stainless steel were investigated. The hot rolled steel strips were subjected to cold rolling at 0 °C from 10 to 90% thickness reduction. Microstructures, strain-induced martensitic transformation and mechanical properties of the cold-rolled specimens were characterized by X-ray diffraction, Feritscope measurements, optical metallography, hardness and tensile tests. The resulting transformation curve showed a sigmoidal shape with the saturation value of strain-induced martensite of approximately 100%. A good agreement was found between the experimental results and the Olsen-Cohen model. The results indicated that formation of strain-induced martensite clearly resulted in a significant strengthening of the steel

  • 22. Hoseyni, M.
    et al.
    Salekbafghi, M.
    Shamanian, M.
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    Coating of MoSi2 on the plain steel substrates by TIG Cladding2008Konferensbidrag (Refereegranskat)
  • 23. Schodek, Daniel L
    et al.
    Ferreira, Paulo
    Ashby, Michael F
    Hedayati, Ali (Översättare)
    Forouzan, Farnoosh (Översättare)
    Soroor, Ghaziof (Översättare)
    Nanomaterials, nanotechnologies and design: an introduction for engineers and architects2016Bok (Övrigt vetenskapligt)
  • 24.
    Suopajärvi, Hannu
    et al.
    Process Metallurgy Research Unit, University of Oulu.
    Umeki, Kentaro
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Mousa, Elsayed
    Swerea MEFOS, Process Integration Department.
    Hedayati, Ali
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Romar, Henrik
    Research Unit of Sustainable Chemistry, University of Oulu.
    Kemppainen, Antti
    Process Metallurgy Research Unit, University of Oulu.
    Wang, Chuan
    Swerea MEFOS, Process Integration Department.
    Phounglamcheik, Aekjuthon
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Tuomikoski, Sari
    Research Unit of Sustainable Chemistry, University of Oulu.
    Norberg, Nicklas
    Future Eco North Sweden AB.
    Andefors, Alf
    Future Eco North Sweden AB.
    Öhman, Marcus
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Lassi, Ulla
    Research Unit of Sustainable Chemistry, University of Oulu.
    Fabritius, Timo
    Process Metallurgy Research Unit, University of Oulu.
    Use of biomass in integrated steelmaking: Status quo, future needs and comparison to other low-CO2 steel production technologies2018Ingår i: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 213, s. 384-407Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper provides a fundamental and critical review of biomass application as a reducing agent and fuel in integrated steelmaking. The basis for the review is derived from the current process and product quality requirements that also biomass-derived fuels should fulfill. The availability and characteristics of different sources of biomass are discussed and suitable pretreatment technologies for their upgrading are evaluated. The existing literature concerning biomass application in bio-coke making, blast furnace injection, iron ore sintering and production of carbon composite agglomerates is reviewed and research gaps filled by providing insights and recommendations to the unresolved challenges. Several possibilities to integrate the production of biomass-based reducing agents with existing industrial infrastructures to lower the cost and increase the total efficiency are given. A comparison of technical challenges and CO2 emission reduction potential between biomass-based steelmaking and other emerging technologies to produce low-CO2 steel is made.

  • 25. Surki, R
    et al.
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    Temperature dependency of strain induced martensitic transformation in metastable austenitic stainless steels2012Konferensbidrag (Refereegranskat)
  • 26.
    Surkialiabad, Roohallah
    et al.
    Department of Materials Engineering, Isfahan University of Technology, Engineering Faculty, Ferdowsi Uniersity of Mashhad.
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    Similar tendency to strain-induced martensite transformation in different austenitic stainless steels2013Ingår i: Materials Performance and Characterization, E-ISSN 2165-3992, Vol. 2, nr 1, s. 206-213Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The formation of strain-induced martensite in metastable austenitic stainless steels depends on many parameters; the most well known and highly investigated of these is temperature. In this work, we suggest a new relationship between Md30/50, deformation temperature (DT), and martensite content based on data gathered from other studies and our experimental findings. For this purpose we rolled an AISI 304L stainless steel in different strains at 25°C, 0°C, and - 15°C; then we characterized the steel via x-ray diffraction and Ferritescope studies to identify different phases and calculate their contents. According to the results, the relationship is as follows: If the delta value (DT - Md30/50) is the same for different austenitic stainless steels, they will form equal amounts of martensite under similar strain conditions. Moreover, both the delta value and the true strain have a strong effect on the formation of martensite.

  • 27.
    Surkialiabad, Roohallah
    et al.
    Department of Materials Engineering, Isfahan University of Technology, Materials Group, Engineering Faculty, Ferdowsi University of Mashhad.
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    Alam, Ali Saheb
    Materials Group, Engineering Faculty, Ferdowsi University of Mashhad.
    Monitoring of Martensitic Transformation in Cold-Rolled 304L Austenitic Stainless Steel by Eddy Current Method2013Ingår i: e-Jounral of Nondestructive Testing, ISSN 1435-4934, Vol. 1, nr 10Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    With measuring the volume fraction of martensite, the destruction of the samples would be considered. In this work a 304L AISI austenitic stainless steel was rolled from 10 to 80 % reduction then the formation of martensite phase was monitored by X-ray diffraction, image analysis of optical, SEM microscopy and eddy current investigation. Also eddy current was carried out in the wide range of frequencies from 50 to 10000 Hz to figure out the effect of it on structural changes then the outputs were calibrated by XRD. By comparing the data of these methods relationship between them was found to be a function of exponential regression. In spite, some researchers have previouslyreported a linear relationship.

  • 28. Torabpour, A
    et al.
    Khorasani, M. R
    Asghari, S
    Hedayati, Ali
    Department of Materials Engineering, Isfahan University of Technology.
    Review process to manufacture metallic bipolar plates in proton exchange membrane fuel cell2012Konferensbidrag (Refereegranskat)
  • 29.
    Vuorinen, Esa
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Heino, V.
    Tampere University of Technology, Department of Materials Science.
    Ojala, N.
    Tampere University of Technology, Department of Materials Science.
    Haiko, O.
    University of Oulu, Faculty of Technology, Materials Engineering.
    Hedayati, Ali
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Erosive-abrasive wear behavior of carbide-free bainitic and boron steels compared in simulated field conditions2018Ingår i: Proceedings of the Institution of mechanical engineers. Part J, journal of engineering tribology, ISSN 1350-6501, E-ISSN 2041-305X, Vol. 232, nr 1, s. 3-13Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The wear resistance of carbide-free bainitic microstructures have recently shown to be excellent in sliding, sliding-rolling, and erosive-abrasive wear. Boron steels are often an economically favorable alternative for similar applications. In this study, the erosive-abrasive wear performance of the carbide-free bainitic and boron steels with different heat treatments was studied in mining-related conditions. The aim was to compare these steels and to study the microstructural features affecting wear rates. The mining-related condition was simulated with an application oriented wear test method utilizing dry abrasive bed of 8–10 mm granite particles. Different wear mechanisms were found; in boron steels, micro-cutting and micro-ploughing were dominating mechanisms, while in the carbide-free bainitic steels, also impact craters with thin platelets were observed. Moreover, the carbide-free bainitic steels had better wear performance, which can be explained by the different microstructure. The carbide-free bainitic steels had fine ferritic-austenitic microstructure, whereas in boron steels microstructure was martensitic. The level of retained austenite was quite high in the carbide-free bainitic steels and that was one of the factors improving the wear performance of these steels. The hardness gradients with orientation of the deformation zone on the wear surfaces were one of the main affecting factors as well. Smoother work hardened hardness profiles were considered beneficial in these erosive-abrasive wear conditions.

  • 30.
    Vuorinen, Esa
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Heino, V.
    Tampere University of Technology, Department of Materials Science.
    Ojala, N.
    Tampere University of Technology, Department of Materials Science.
    Haiko, O.
    University of Oulu, Faculty of Technology, Materials Engineering.
    Hedayati, Ali
    The effects of microstructure on erosive-abrasive wear behavior of carbide free bainitic and boron steels2016Ingår i: Nordic Symposium on Tribology - NORDTRIB 2016, 2016Konferensbidrag (Refereegranskat)
  • 31.
    Vuorinen, Esa
    et al.
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Hosseini, Nazanin
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Materialvetenskap.
    Hedayati, Ali
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik, Energivetenskap.
    Kornacker, Eva
    Luleå tekniska universitet, Institutionen för teknikvetenskap och matematik.
    Fernandez, Maria Teresa
    CIDAUT Foundation, Boecillo, Spain.
    Sanz, Javier
    CIDAUT Foundation, Boecillo, Spain.
    Gonzalez, Manuel I.
    CIDAUT Foundation, Boecillo, Spain.
    Cañibano, Esteban
    CIDAUT Foundation, Boecillo, Spain.
    Mechanical and microstructural evaluation of high performance steel (S700MC) for road restraint systems2020Ingår i: Engineering Failure Analysis, ISSN 1350-6307, E-ISSN 1873-1961, Vol. 108, artikel-id 104251Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The suitability of using high performance steel (S700MC) for road restraint systems (RRS) under very high containment level was evaluated in this study. To investigate the influence of the crash on the mechanical behaviour of the steel, different test pieces were tested by tensile and hardness testing, and examined by scanning electron microscopy (SEM). The tensile test results of S700MC showed a noticeable increase in yield strength at 0.2% elongation (Rp0.2) from 744 to 935 MPa, and ultimate tensile strength (UTS) from 810 to 1017 MPa, before and after crash tests (BC and AC, respectively). S700MC showed ~9% lower elongation at fracture value in comparison with S275JR and S355JR steels. Besides, fracture toughness, was significantly higher for S700MC (133 and 148 MJ/m3 for BC and AC, respectively) compared to conventional mild steels (108–118 MJ/m3). Microstructural observations of head-part of all S700MC samples revealed equi-axed grains. The fracture surface of tensile tested samples before crash, showed elongated grains accompanied by pore formation. Among after crash samples, one test piece showed intergranular cracks while no intergranular cracks were observed for the other crashed pieces which resulted in the lower Rp0.2 (813 MPa) and UTS strength (847 MPa) and fracture toughness (125 MJ/m3). The results showed that although RRS manufactured with S700MC undergoes severe mechanical deformation, the risk of brittle fracture is very low and this is beneficial from industrial as well as social point of view.

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