Austenite grain growth and hot deformation behavior in a medium carbon low alloy steel

Chamanfar, A.; Chentouf, S.M.; Jahazi, Mohammad; Lapierre-Boire, Louis-Philippe

doi:10.1016/j.jmrt.2020.08.114

Cited by 32 publications

(19 citation statements)

References 33 publications

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“…[ 33–35 ] As increasing the austenitizing time (from 30 to 120 min at 860 °C), the austenite grains grow and become coarsening so that the grain size is increased simultaneously. [ 36,37 ]…”

Section: Resultsmentioning

confidence: 99%

“…[33][34][35] As increasing the austenitizing time (from 30 to 120 min at 860 C), the austenite grains grow and become coarsening so that the grain size is increased simultaneously. [36,37] Table S2, Supporting Information, summarizes the mechanical properties as well as the aforementioned average grain size under various austenitizing time. The YS and UTS decrease simultaneously with increasing the austenitizing time.…”

Section: Effects Of Austenitizing Time On Yrmentioning

confidence: 99%

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Achieving Low Yield Ratio in High‐Strength Steel by Tuning Multiple Microstructures

Shi

Wang

Gao

et al. 2021

steel research int.

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Herein, martensite–ferrite dual‐phase high‐strength low‐alloy (HSLA) steels with a low yield ratio (YR), which is achieved through different heat‐treatment procedures, are evaluated in terms of multiple microstructures, e.g., grain size, soft‐phase proportion, and morphology. The extended austenitizing time exhibits a low YR by sacrificing both the yield and tensile strengths synchronously. By subtly regulating the tempering temperatures, the YR can be optimized from 0.93 to 0.89 after tempering at an applicable temperature. Moreover, by introducing the equivalent shape factor (ESF), the morphology effects of ferrite on the YR are investigated based on the microstructural observation and Abaqus finite element analysis. The YR is inversely proportional to the ESF of the microstructure, which can be used to guide the design of microstructural morphology. The correlation between the yield strength (YS), YR, and work hardening exponent is achieved using the Swift equation. The lower YR generates greater work hardening and reduced YS. By tuning multiple microstructures, high YS and relatively low YR are achieved via the secondary‐quenching intercritical heat treatment, which is beneficial for designing low‐yield‐ratio HSLA steels in industrial applications.

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Section: Resultsmentioning

confidence: 99%

Section: Effects Of Austenitizing Time On Yrmentioning

confidence: 99%

Achieving Low Yield Ratio in High‐Strength Steel by Tuning Multiple Microstructures

Shi

Wang

Gao

et al. 2021

steel research int.

View full text Add to dashboard Cite

show abstract

“…In this way, and as acquired in an early work 9 , the modeling of the flow curves of this material, as well as the (JMAK) "Johnson-Mehl-Avrami-Kolmogorov" parameters 10 , are necessary for assessing its microstructural evolution such as in recrystallization kinetics. Thus, enabling the application of "semi-empirical" numerical models, based on methods previously proposed by [11][12][13][14][15][16][17] , which can simulate the complexity of the hot forging process and the grain size evolution.…”

Section: Introductionmentioning

confidence: 99%

Numerical and Experimental Study of an Industrial Case for Grain Size Evolution in Bainitic Steel in Controlled Hot Forging and its Influence on Mechanical Performance

et al. 2022

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Controlling the recrystallization is an important way to reach grain size refinement and outstanding strength and toughness on alloy metals. This study sets out the application and investigation of mathematical microstructure modeling of a newly designed bainitic steel for hot forging industrial applications. The macro-scale model was used to observe and predict the austenitic grain size behavior during the controlled forging of a gear. Arrhenius grain growth kinetic and recrystallization model for a new class of bainitic steel was established for the given strain rate ranges and temperatures. This model was calibrated through microscopic analysis and used to simulate the unpublished constants of low alloyed bainitic forging steel DIN 18MnCrSiMo6-4 microstructure module using DEFORM® commercial finite element code. The increased temperature due to the adiabatic effect was investigated by numerical analysis, demonstrating its influence on grain coarsening. Local tensile test and Charpy-V notch were compared at different industrial hot forging temperatures and local plastic strain. Changes in yield strength and ductility have demonstrated the grain size influence on the processing parameters. The employed numerical model was an efficient tool to predict and present an alternative path to develop robust industrial forging using semi-empirical models.

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“…Heat treatment of dual steels leads to partial austenitisation, and during cooling austenite transforms into martensite. The kinetics of austenite formation at given temperature is mostly described by the Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ], including recent papers specifically on dual steels [ 21 , 22 , 23 ], only rarely it is replaced by modelling and simulations, e.g., [ 24 ]. Usual form of the JMAK equation is:

where p is conversion, i.e., the relative content of the newly formed phase.…”

Section: Introductionmentioning

confidence: 99%

Simple and Precise Description of the Transformation Kinetics and Final Structure of Dual Phase Steels

Kohout

2021

Materials

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The kinetics of diffusion-dependent phase transformations (including austenitisation of ferrite in dual steels or ferritic nodular cast irons) is very often described by the Johnson–Mehl–Avrami–Kolmogorov (JMAK) equation. This description is not complete when the conversion is only partial due to insufficient overheating, as the equilibrium fraction of ferrite transformed into austenite cannot be determined directly from the JMAK equation. Experimental kinetic curves of partial austenitisation at various temperatures can be fitted using the JMAK equation, but the equilibrium fraction of the newly formed phase for each temperature has to be calculated as a regression parameter. In addition, the temperature dependence of the kinetic exponent in the JMAK equation is quite complicated and cannot be expressed by a simple general function. On the contrary, the equation of autoinhibition used for the description of austenitisation kinetics in present work directly gives the equilibrium fraction at partial conversion. It describes transformation kinetics at various temperatures independently of whether the conversion is complete or partial. Rate constants of the equation of autoinhibition depend on temperature according to the Arrhenius equation. In addition, the equation of autoinhibition has no weakness as the JMAK equation has, which consists in questionable temperature dependence of kinetic exponent.

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Austenite grain growth and hot deformation behavior in a medium carbon low alloy steel

Cited by 32 publications

References 33 publications

Achieving Low Yield Ratio in High‐Strength Steel by Tuning Multiple Microstructures

Achieving Low Yield Ratio in High‐Strength Steel by Tuning Multiple Microstructures

Numerical and Experimental Study of an Industrial Case for Grain Size Evolution in Bainitic Steel in Controlled Hot Forging and its Influence on Mechanical Performance

Simple and Precise Description of the Transformation Kinetics and Final Structure of Dual Phase Steels

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