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Mehran Zamani - One of the best experts on this subject based on the ideXlab platform.
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Ferrite recrystallisation and Intercritical Annealing of cold-rolled low alloy medium carbon steel
Materials Science and Technology, 2019Co-Authors: Mohammad Tavakoli, Hamed Mirzadeh, Mehran ZamaniAbstract:Static recrystallisation of cold-rolled AISI 4130 medium carbon steel in the ferritic regime and its response to Intercritical Annealing treatment are studied. A fine and recrystallised microstruct...
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synergistic effects of holding time at Intercritical Annealing temperature and initial microstructure on the mechanical properties of dual phase steel
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2019Co-Authors: Fatemeh Jamei, Hamed Mirzadeh, Mehran ZamaniAbstract:Abstract The synergistic effects of the initial microstructure and the Intercritical Annealing time on the microstructure and tensile properties of low carbon steel were studied. It was found that by refining the pre-Intercritical Annealing microstructure, the resulting duplex DP microstructure becomes finer, which results in the enhancement of the tensile properties and work-hardening behavior. Based on the hardness measurements, three stages were identified for Intercritical Annealing: initial rise or fall, reaching a plateau, and final fall to a low value. The pre-Intercritical Annealing microstructure did not show any pronounced effects on these stages, with the exception of the short-lived initial stage. It was shown that the DP steel obtained right after reaching the abovementioned plateau can exhibit improved mechanical properties and work-hardening behavior. During the third stage, the enrichment of manganese in austenite and the concurrent grain growth were found to be the main factors taking part in the change of hardness and tensile strength and reappearance of the yield-point elongation. The impact of the microstructural features (austenite and ferrite) on the grain growth behavior during Intercritical Annealing and the effect of the grain size on the Luders strain were also discussed.
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Improved mechanical properties of mild steel via combination of deformation, Intercritical Annealing, and quench aging
Materials Science and Engineering: A, 2019Co-Authors: Sheida Nikkhah, Hamed Mirzadeh, Mehran ZamaniAbstract:Abstract Processing of dual phase steel with fine ferrite grains containing nanometric carbides and chain-like morphology of martensite from a 0.035C-0.005N-0.035Si-0.268Mn mild steel was realized via application of high cold rolling reductions, Intercritical heat treatment, and room-temperature aging, which showed a yield stress (YS) of 450 MPa and ultimate tensile strength (UTS) of 700 MPa. It was revealed that significant enhancements in tensile properties can be achieved compared to the separate effects of Intercritical Annealing (YS of 130 MPa and UTS of 385 MPa), cold rolling and Intercritical Annealing (YS of 300 MPa and UTS of 600 MPa), and quench aging (YS of 275 MPa and UTS of 520 MPa). The results were rationalized based on the grain size strengthening, aging effect, and work-hardening behavior.
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Fine tuning the mechanical properties of dual phase steel via thermomechanical processing of cold rolling and Intercritical Annealing
Materials Chemistry and Physics, 2019Co-Authors: Sheida Nikkhah, Hamed Mirzadeh, Mehran ZamaniAbstract:Abstract The simultaneous effects of cold rolling reduction and Intercritical Annealing time on the microstructure and tensile properties of St12 steel were studied. It was revealed that by increasing the rolling reduction, the ferrite grain size of the dual phase (DP) microstructure is refined and a chain-like morphology of martensite develops, which results in improvement of work-hardening capacity and the tensile properties. Such a microstructure can be obtained via applying an optimum holding time at the Intercritical Annealing temperature. Beyond that optimum, grain coarsening occurs with the resulting deterioration of tensile properties. It was also shown that by consideration of quenched sheet or by applying low reductions in thickness, secondary recrystallization or abnormal grain growth (AGG) takes place during Intercritical Annealing, which is characterized by small grains and some large ferrite grains containing martensite islands. This study clarified that applying high reduction in thickness for grain refinement and also controlling the holding time in the two-phase austenite-ferrite region are the essential prerequisites to achieve the desired tensile strength, ductility, and toughness.
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Processing of Fine-Grained DP300/600 Dual Phase Steel from St12 Structural Steel by the Thermo-Mechanical Processing of Cold Rolling and Intercritical Annealing
international journal of iron and steel society of iran, 2018Co-Authors: Mehran Zamani, Hamed Mirzadeh, Mahsa NourooziAbstract:The effect of microstructural refinement and Intercritical Annealing on the mechanical properties and work-hardening response of a low carbon St12 steel was studied. It was revealed that Intercritical Annealing of the ferritic-pearlitic sheet results in the formation of a coarse-grained DP microstructure with discrete martensite islands normally formed in place of pearlitic colonies, which results in the minor enhancement of mechanical properties with disappearance of the yield-point elongation. On the other hand, a fine-grained DP steel with chain-network martensite morphology can be obtained by Intercritical Annealing of the cold rolled martensitic microstructure, which shows superior work hardening rate, low yield ratio, and high tensile strength. In this way, it is possible to enhance the mechanical properties of St12 steel toward those of DP300/600 steel. Compared with the conventional DP350/600 grade, a significant enhancement in the work-hardening behavior can be achieved with acceptable strength-ductility balance compared with the usual trend seen in steels. As a result, it was concluded that cold rolling of the initial martensitic microstructure before Intercritical Annealing is a viable approach for processing DP steels with enhanced mechanical properties for industrial applications.
Hamed Mirzadeh - One of the best experts on this subject based on the ideXlab platform.
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Effects of spheroidization heat treatment and Intercritical Annealing on mechanical properties and corrosion resistance of medium carbon dual phase steel
Materials Chemistry and Physics, 2021Co-Authors: Maryam Soleimani, Hamed Mirzadeh, Changiz DehghanianAbstract:Abstract Spheroidization heat treatment and Intercritical Annealing and their effects on the mechanical properties and corrosion behavior of CK45 medium carbon steel were studied. Increasing the spheroidization time resulted in the decline of strength and hardness of the initial martensitic steel but improved the tensile ductility and corrosion resistance. Intercritical Annealing of the spheroidized steels resulted in the formation of austenite at the expense of cementite particles at short Intercritical Annealing times, which resulted in the development of dual phase (DP) steels after water quenching. Increasing the holding time at the Intercritical Annealing temperature led to a remarkable increase in the volume fraction of martensite in the microstructure, leading to poor ductility and corrosion resistance. This processing route, however, made it possible to obtain low martensite contents via short Intercritical Annealing of spheroidized steels, which resulted in the enhancement of strength-ductility balance while maintaining appropriate corrosion resistance.
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Controlling the Mechanical Properties and Corrosion Resistance of Mild Steel by Intercritical Annealing and Subcritical Tempering
2020Co-Authors: Maryam Soleimani, Hamed Mirzadeh, Changiz DehghanianAbstract:The effects of Intercritical Annealing and subcritical tempering on the mechanical properties and corrosion resistance of mild steel were studied. It was revealed that Intercritical Annealing followed by quenching resulted in the development of a ferritic-martensitic dual phase (DP) microstructure with high tensile strength, disappearance of the yield-point phenomenon, superior work-hardening behavior, and decreased corrosion resistance. Subsequent tempering of the Intercritically annealed steel resulted in the formation of carbide particles in a tempered martensitic microstructure, which led to the decline of the strength and hardness, reappearance of the yield-point elongation, and enhanced corrosion resistance. Accordingly, this work demonstrated the possibility of controlling the mechanical properties and corrosion resistance of commercial mild steels by simple heat treatments.
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Improved properties of dual-phase steel via pre-Intercritical Annealing treatment and thermal cycling
Materials Science and Technology, 2020Co-Authors: Sajad Ghaemifar, Hamed Mirzadeh, Mahmoud Sarkari Khorrami, Reza Soltani, Zahra NasiriAbstract:The synergistic effects of pre-Intercritical Annealing treatments and multiple heating to the two-phase region (followed by quenching) on the microstructure and mechanical properties of dual-phase ...
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Ferrite recrystallisation and Intercritical Annealing of cold-rolled low alloy medium carbon steel
Materials Science and Technology, 2019Co-Authors: Mohammad Tavakoli, Hamed Mirzadeh, Mehran ZamaniAbstract:Static recrystallisation of cold-rolled AISI 4130 medium carbon steel in the ferritic regime and its response to Intercritical Annealing treatment are studied. A fine and recrystallised microstruct...
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synergistic effects of holding time at Intercritical Annealing temperature and initial microstructure on the mechanical properties of dual phase steel
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2019Co-Authors: Fatemeh Jamei, Hamed Mirzadeh, Mehran ZamaniAbstract:Abstract The synergistic effects of the initial microstructure and the Intercritical Annealing time on the microstructure and tensile properties of low carbon steel were studied. It was found that by refining the pre-Intercritical Annealing microstructure, the resulting duplex DP microstructure becomes finer, which results in the enhancement of the tensile properties and work-hardening behavior. Based on the hardness measurements, three stages were identified for Intercritical Annealing: initial rise or fall, reaching a plateau, and final fall to a low value. The pre-Intercritical Annealing microstructure did not show any pronounced effects on these stages, with the exception of the short-lived initial stage. It was shown that the DP steel obtained right after reaching the abovementioned plateau can exhibit improved mechanical properties and work-hardening behavior. During the third stage, the enrichment of manganese in austenite and the concurrent grain growth were found to be the main factors taking part in the change of hardness and tensile strength and reappearance of the yield-point elongation. The impact of the microstructural features (austenite and ferrite) on the grain growth behavior during Intercritical Annealing and the effect of the grain size on the Luders strain were also discussed.
R.d.k. Misra - One of the best experts on this subject based on the ideXlab platform.
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improved strength ductility toughness balance of a precipitation strengthened low carbon medium mn steel by adopting Intercritical Annealing tempering process
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2021Co-Authors: Ying Zou, G Wang, Y Han, H X Teng, D Han, M S Qiu, F Yang, R.d.k. MisraAbstract:Abstract The present study on low-carbon medium-Mn steel demonstrates that the newly proposed “Intercritical Annealing-tempering” process led to good combination of strength, ductility and impact toughness, by simultaneously optimizing austenite reverted transformation and Cu precipitation. Intercritical Annealing at high temperature accelerated the dissolution of cementite particles, promoted the formation of reverted austenite, and then increased the total elongation and impact energy. The additional tempering at 500 °C facilitated intensive precipitation of Cu-rich precipitates in secondary martensite. The precipitates were fine, uniform in size and high in density, which provided a significant strengthening effect. Strengthening by nano-scale Cu-rich precipitates compensated softening associated with high temperature Annealing, and increased the yield strength of tempered medium-Mn steel by 75 MPa. In addition to facilitating Cu precipitation, the introduction of secondary martensite also promoted nucleation of reverted austenite during tempering with sufficient C and Mn concentration that stabilized austenite and further improved ductility. Excellent mechanical properties, 960 MPa yield strength, 1010 MPa tensile strength, 29.2% total elongation and 150 J impact energy at room temperature were obtained in the precipitation-strengthened low-carbon medium-Mn steel, on Intercritical Annealing at 645 °C, followed by tempering at 500 °C for 2 h.
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microstructural evolution and mechanical properties of 9mn steel during warm cold rolling and subsequent Intercritical Annealing
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2020Co-Authors: Ning Yan, R.d.k. Misra, X H GongAbstract:Abstract The microstructural evolution of 9Mn steel during warm rolling in the Intercritical region and cold rolling, both followed by subsequent Intercritical Annealing was studied. A significantly different microstructure was obtained by warm rolling and cold rolling, the former contained austenite and deformed ferrite/martensite and the latter consisted of deformed ferrite and transformed martensite, which significantly impacted the microstructure after Intercritical Annealing. The existence of austenite in warm-rolled sample reduced the elemental content in the deformed matrix, weakening the kinetics of austenite formation during subsequent Annealing. In addition, the occurrence of dynamic recovery during warm rolling led to a low storage energy of recrystallization, resulting in a partial recrystallization of ferrite during IA. However, a slightly larger volume fraction as well as more heterogeneous austenite morphology with a wide austenite size distribution was obtained by combining both warm rolling and Annealing. These austenite grains could transform to martensite in a more sustainable way, increasing the TRIP-related strain. Consequently, the warm-rolled + annealed steel showed a better combination of ultimate tensile strength (1380 MPa) and total elongation (29.11%).
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The determining role of Intercritical Annealing condition on retained austenite and mechanical properties of a low carbon steel: Experimental and theoretical analysis
Materials Characterization, 2019Co-Authors: Z.j. Xie, Chengjia Shang, G. Han, R.d.k. MisraAbstract:Abstract The impact of Intercritical Annealing (IA) temperature and time on retained austenite and mechanical properties are elucidated in a low carbon steel containing 2.85 wt% Mn. Experimental studies indicated that the multi-phase microstructure consisted of Intercritical ferrite, martensite/bainite, retained austenite and fine dispersion of precipitations. The volume fraction of retained austenite attained a maximum value of 14% on IA at 680 °C for 30 min. The partition behavior of alloying elements during Intercritical Annealing was studied by scanning transmission electron microscopy (STEM) and analyzed kinetically by DICTRA simulation. Appropriate fraction of retained austenite obtained at 680 °C for 30 min was attributed to the extent of partitioning of carbon and manganese into the reverted austenite that contributed to best balance of mechanical properties.
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Microstructure and mechanical properties of a novel hot-rolled 4% Mn steel processed by Intercritical Annealing
Journal of Materials Science, 2018Co-Authors: Wang Hesong, Zhang Yuanxiang, Jian Kang, R.d.k. Misra, Guo Yuan, Lan Mengfei, Cao Guangming, Guodong WangAbstract:The study described here focuses on the microstructure and mechanical properties of a novel hot-rolled medium-Mn steel (Fe–0.25C–4Mn–1.88Al–0.6Si–0.04Nb–0.08V, wt%) that contained only 4 wt% Mn and modest Al content of 1.88 wt%. It was found that a relatively high content (25–53 vol%) of retained austenite was obtained by Intercritical Annealing process. With increase in Intercritical Annealing temperature from 700 to 740 and to 760 °C, retained austenite fraction increased from 25.1 to 53.2% and then decreased to 46.1%. Besides, mechanical stability of retained austenite in 700–760 °C Intercritically annealed steels decreased with increase in Intercritical Annealing temperature. The 720 °C Intercritically annealed steel yielded excellent mechanical properties with yield strength of 766 MPa, tensile strength of 951 MPa, total elongation of 48.6% and PSE of 46.22 GPa·%, achieved by a high volume fraction of retained austenite (46%) with relatively high mechanical stability. Thus, the 4% Mn steel present in this study indicated excellent mechanical properties of medium-Mn steels can be achieved using low alloy content.
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structure mechanical property relationship in a high strength low carbon alloy steel processed by two step Intercritical Annealing and Intercritical tempering
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014Co-Authors: W H Zhou, X L Wang, P K C Venkatsurya, Hui Guo, Chengjia Shang, R.d.k. MisraAbstract:Abstract The influence of Annealing and tempering temperature on the microstructure and mechanical properties was investigated in a low carbon alloy steel that was processed by a two-step Intercritical Annealing and Intercritical tempering heat treatment. In general, the microstructure of the processed steel comprises Intercritical lath-like ferrite, bainitic/martensitic lath and acicular-type retained austenite. The lower Intercritical Annealing temperature resulted in lower fraction of Intercritical ferrite with finer grain size and consequently higher strength. On the other hand, the Intercritical tempering temperature significantly influenced retained austenite content and precipitation. High fraction of retained austenite was obtained at a temperature slightly above Ac 1 temperature and retained austenite content decreased with increase in tempering temperature. This behavior is attributed to the competition between the enrichment of Mn and Ni and the fraction of reversed austenite. Fine niobium carbide precipitates of size ~2–6 nm and copper precipitates of size range ~10–30 nm were obtained. The optimal Intercritical Annealing and tempering temperatures to obtain the product of tensile strength and elongation % of ~30 GPa% were 780 °C and 660 °C, respectively and the volume fraction of retained austenite was ~29%.
Dagoberto Brandão Santos - One of the best experts on this subject based on the ideXlab platform.
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Analysis of medium manganese steel through cold-rolling and Intercritical Annealing or warm-rolling
Materials Science and Technology, 2018Co-Authors: Aline Silva Magalhães, Carlos Eduardo Santos, Aline Oliveira Vasconcelos Ferreira, Davi Silva Alves, Dagoberto Brandão SantosAbstract:ABSTRACTMedium manganese steel is typically fabricated from hot-rolling followed by cold-rolling and Intercritical Annealing processes. However, a singular process, warm-rolling, is an appealing pr...
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Evolution of Texture in Ultra-Fine Grained Ferrite through Warm-Rolling and Intercritical Annealing
Materials Science Forum, 2008Co-Authors: Sandip Ghosh Chowdhury, B. Mahato, Hezio Rosa Da Silva, Gustavo Gonçalves Lourenço, Dagoberto Brandão SantosAbstract:The ferrite grain size refining is the unique mechanism for increasing both mechanical strength and formability of steels. Steel with an ultra-fine ferrite grained structure must show a good relation between mechanical strength, ductility and toughness, while the low carbon content enhances good welding characteristics. The objective of this work is to investigate the influence of warm rolling on the evolution of texture in a microalloyed low carbon-manganese (0.11%C, 1.41%Mn, 0.028%Nb and 0.012%Ti) steel with ultra-fine grains produced through out quenching, warm rolling, followed by sub and Intercritical Annealing. The evolution of restoration process - recovery and recrystallization - was followed by optical and scanning microscopy. After subcritical Annealing, the microstructure was formed by spheroidal iron carbides and a ferritic recovered matrix. Otherwise, after Intercritical Annealing, the microstructure was composed mainly by ultrafine grain polygonal ferrite, MA (martensite-austenite) constituent and carbides. The mechanical behaviour of the steel was evaluated using tensile tests. The mechanical properties have been correlated with the evolution of texture in the ultra-fine grained ferrites.
Yousef Mazaheri - One of the best experts on this subject based on the ideXlab platform.
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The effect of Nb on texture evolutions of the ultrafine-grained dual-phase steels fabricated by cold rolling and Intercritical Annealing
Journal of Alloys and Compounds, 2017Co-Authors: A. Ghatei Kalashami, Abbas Najafizadeh, Ahmad Kermanpur, Ehsan Ghassemali, Yousef MazaheriAbstract:Dual phase (DP) steels with different amounts of Nb were produced by utilizing cold rolling and Intercritical Annealing of a ferrite-martensite duplex starting structure. The effects of Nb contents ...
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development of a high strength and ductile nb bearing dual phase steel by cold rolling and Intercritical Annealing of the ferrite martensite microstructures
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2016Co-Authors: Ali Ghatei Kalashami, Abbas Najafizadeh, A Kermanpur, Yousef MazaheriAbstract:Abstract Dual phase (DP) steels containing different amounts of Nb microalloying element were produced by cold-rolling followed by Intercritical Annealing of a ferrite-martensite duplex starting structure. The effects of Nb contents (0.00, 0.06, 0.12 and 0.18 wt%) and Intercritical Annealing time on the microstructural evolutions and mechanical properties were studied. Results from microscopic images showed that increasing Nb content increased the volume fraction of martensite and decreased the average grain size of ferrite. Tensile results illustrated an excellent strength-elongation balance in terms of energy absorption (160 J cm −3 ) and toughness (229 MPa). The lowest grain size of about 1.40±0.37 µm was achieved in the DP steel containing 0.12 wt% Nb whose strength was about 123% higher than that of the as-received ferritic-pearlitic steel (e.g. 540 MPa), without loss of ductility. The variations of strength, elongation and fracture mechanism of the specimens with Nb contents and Intercritical Annealing time were correlated to the microstructural features.
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Kinetics of Ferrite Recrystallization and Austenite Formation During Intercritical Annealing of the Cold-Rolled Ferrite/Martensite Duplex Structures
Metallurgical and Materials Transactions A, 2016Co-Authors: Yousef Mazaheri, Ahmad Kermanpur, Abbas Najafizadeh, A. Ghatei KalashamiAbstract:Ultrafine-grained, dual-phase (UFG DP) steels were produced by a new route using an uncommon cold-rolling and subsequent Intercritical Annealing of ferrite/martensite duplex starting microstructures. The effects of processing parameters such as rolling reduction, Intercritical Annealing temperature, and time on the microstructural evaluations have been studied. UFG DP steels with an average grain size of about 1 to 2 μm were achieved by short Intercritical Annealing of the 80 pct cold-rolled duplex microstructures. The kinetics of ferrite recrystallization and austenite formation were studied based on the Johnson–Mehl–Avrami–Kolmogorov (JMAK) model. The proposed model for describing the isothermal austenite formation kinetics was applied successfully to the nonisothermal conditions. It was found that complete recrystallization of ferrite before the austenite formation led to the formation of a large extent randomly distributed austenite in the ferrite matrix and a chain-networked structure.
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kinetics of ferrite recrystallization and austenite formation during Intercritical Annealing of the cold rolled ferrite martensite duplex structures
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2016Co-Authors: Yousef Mazaheri, Ahmad Kermanpur, Abbas Najafizadeh, Ghatei A KalashamiAbstract:Ultrafine-grained, dual-phase (UFG DP) steels were produced by a new route using an uncommon cold-rolling and subsequent Intercritical Annealing of ferrite/martensite duplex starting microstructures. The effects of processing parameters such as rolling reduction, Intercritical Annealing temperature, and time on the microstructural evaluations have been studied. UFG DP steels with an average grain size of about 1 to 2 μm were achieved by short Intercritical Annealing of the 80 pct cold-rolled duplex microstructures. The kinetics of ferrite recrystallization and austenite formation were studied based on the Johnson–Mehl–Avrami–Kolmogorov (JMAK) model. The proposed model for describing the isothermal austenite formation kinetics was applied successfully to the nonisothermal conditions. It was found that complete recrystallization of ferrite before the austenite formation led to the formation of a large extent randomly distributed austenite in the ferrite matrix and a chain-networked structure.