Effects of isothermal transformation conditions on the microstructure and hardness values of a high-carbon Al–Si alloyed steel

Baradari, Sadjad; Boutorabi, S. M. A.

doi:10.1016/j.matdes.2015.07.151

Cited by 18 publications

(6 citation statements)

References 52 publications

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“…The nature of ICT phenomenon could be explained by the concept of the T 0 curve [14,15], which places strict limits on the maximum fraction of transformation that can be achieved theoretically. In fact, both theoretical calculation and experimental results have proven that a lower transformation temperature can lead to an increase of bainite formation [16][17][18]. However, the time for transformation could be prolonged below the nose temperature of the time-temperature-transformation (TTT) curve, which is inversely correlated to the expectation.…”

Section: Introductionmentioning

confidence: 99%

Combined Effects of Deformation and Undercooling on Isothermal Bainitic Transformation in an Fe-C-Mn-Si Alloy

Zou

et al. 2019

Metals

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Both ausforming and transformation temperature affect the successive bainitic transformation and microstructure. The individual influence of each case is clear, whereas the combined effects are still unknown. Thermomechanical simulation and metallography were used to investigate the combined effects of ausforming and transformation temperature on bainitic transformation and microstructure. The kinetics of isothermal bainitic transformation in non-deformed and deformed materials was analyzed. A lower transformation temperature can lead to more bainite formation without deformation. However, ausforming with small strains can partially compensate for the decrease of bainite amount caused by the decreased undercooling. The larger the applied strain is, the smaller the difference between the final amounts of bainite with different undercooling. Ausforming at a relatively higher temperature is more favorable to the acceleration of subsequent isothermal bainitic transformation. The results in the present work provide reference for optimizing the fabrication technology of medium-carbon nanobainite steels.

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Section: Introductionmentioning

confidence: 99%

Combined Effects of Deformation and Undercooling on Isothermal Bainitic Transformation in an Fe-C-Mn-Si Alloy

Zou

et al. 2019

Metals

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“…Generally, both factors are determined by the chemical composition and austempering temperature. The effects of austempering temperature above martensite starting temperature (M S ) on the transformation and microstructure of bainitic steel have been widely reported in recent years . For further understanding the bainite transformation and improving the comprehensive property of bainite steels, some researchers used the isothermal transformation temperature below M S .…”

Section: Introductionmentioning

confidence: 99%

“…The effects of austempering temperature above martensite starting temperature (M S ) on the transformation and microstructure of bainitic steel have been widely reported in recent years. [7][8][9][10][11] For further understanding the bainite transformation and improving the comprehensive property of bainite steels, some researchers used the isothermal transformation temperature below M S . They based on the mechanism that lower transformation temperature can provide the larger driving force, which may be useful to obtain a finer microstructure.…”

Section: Introductionmentioning

confidence: 99%

Refined Bainite Microstructure and Mechanical Properties of a High‐Strength Low‐Carbon Bainitic Steel Treated by Austempering Below and Above M_S

Tian

Zhou

et al. 2018

steel research int.

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Four isothermal heat treatment schedules are designed to study the effects of transformation temperature below and above martensite starting temperature (M S ) on bainitic transformation kinetics, microstructure, and mechanical properties of a low-carbon bainitic steel. The results indicate that the product of tensile strength and elongation (PSE) of tested steel do not show any improvement when the samples are austempered at a temperature below M S . Finer bainite microstructure can be observed when the samples are austempered at a temperature below M S , but the highest PSE is obtained in the sample austempered at a temperature above M S (400 C). Lower PSE of the samples transformed below M S is mainly attributed to less bainite and retained austenite (RA) amount and more amount of athermal martensite, as well as the existence of carbide. In addition, with the decrease of the isothermal transformation temperature, the PSE first increases and then decreases. Different from austempering above M S , when the sample is austempered below M S , PSE decreases with the decrease of transformation temperature. Moreover, whether the treatment below M S can improve mechanical property of bainitic steels depends on the composition of steels and transformation temperature.

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“…According to Eq. (1) proposed by Andrews formula [19], the Ac 3 (°C) temperatures were calculated to be 809 and 794 °C for Ni-free steel and Ni-added steel, respectively.…”

Section: Methodsmentioning

confidence: 99%

Effect of Ni Addition on Bainite Transformation and Properties in a 2000 MPa Grade Ultrahigh Strength Bainitic Steel

Tian

Jiang

et al. 2018

Met. Mater. Int.

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The effects of Nickle (Ni) addition on bainitic transformation and property of ultrahigh strength bainitic steels are investigated by three austempering processes. The results indicate that Ni addition hinders the isothermal bainite transformation kinetics, and decreases the volume fraction of bainite due to the decrease of chemical driving force for nucleation and growth of bainite transformation. Moreover, the product of tensile strength and total elongation (PSE) of high carbon bainitic steels decreases with Ni addition at higher austempering temperatures (220 and 250 °C), while it shows no significant difference at lower austempering temperature (200 °C). For the same steel (Ni-free or Ni-added steel), the amounts of bainite and RA firstly increase and then decrease with the increase of the austempering temperature, resulting in the highest PSE in the sample austempered at temperature of 220 °C. In addition, the effects of austempering time on bainite amount and property of high carbon bainitic steels are also analyzed. It indicates that in a given transformation time range of 30 h, more volume of bainite and better mechanical property in high carbon bainitic steels can be obtained by increasing the isothermal transformation time.

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Effects of isothermal transformation conditions on the microstructure and hardness values of a high-carbon Al–Si alloyed steel

Cited by 18 publications

References 52 publications

Combined Effects of Deformation and Undercooling on Isothermal Bainitic Transformation in an Fe-C-Mn-Si Alloy

Combined Effects of Deformation and Undercooling on Isothermal Bainitic Transformation in an Fe-C-Mn-Si Alloy

Refined Bainite Microstructure and Mechanical Properties of a High‐Strength Low‐Carbon Bainitic Steel Treated by Austempering Below and Above M_S

Effect of Ni Addition on Bainite Transformation and Properties in a 2000 MPa Grade Ultrahigh Strength Bainitic Steel

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Effects of isothermal transformation conditions on the microstructure and hardness values of a high-carbon Al–Si alloyed steel

Cited by 18 publications

References 52 publications

Combined Effects of Deformation and Undercooling on Isothermal Bainitic Transformation in an Fe-C-Mn-Si Alloy

Combined Effects of Deformation and Undercooling on Isothermal Bainitic Transformation in an Fe-C-Mn-Si Alloy

Refined Bainite Microstructure and Mechanical Properties of a High‐Strength Low‐Carbon Bainitic Steel Treated by Austempering Below and Above MS

Effect of Ni Addition on Bainite Transformation and Properties in a 2000 MPa Grade Ultrahigh Strength Bainitic Steel

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Refined Bainite Microstructure and Mechanical Properties of a High‐Strength Low‐Carbon Bainitic Steel Treated by Austempering Below and Above M_S