Processing of Ultrafine-Grained Steels by Warm Rolling and Annealing

Bhattacharya, A.; Karmakar, Anish; Karani, Arnab; Ghosh, Mainak; Chakrabarti, Debalay

doi:10.1007/s11665-018-3846-0

Cited by 5 publications

(4 citation statements)

References 50 publications

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“…a_{\text{Ce}} \cdot a_{\text{C}}^{2} \left.\right)\right)_{\text{eq}}$, respectively. The Brody–Flemings model modified by Clyne and Kurz [ 4,34–38 ] is adopted to evaluate the solute redistribution elements during solidification, assuming limited diffusion in the solid phase and complete diffusion in the liquid phase, as elucidated in Equation (8)–(14). [ 37 ]

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Section: Discussionmentioning

confidence: 99%

“…CeP, CeAs, and CeC 2 tend to precipitate in the form of inclusions during the solidification process when the actual activity products ða Ce ⋅ a P Þ ac , ða Ce ⋅ a As Þ ac , and ða Ce ⋅ a 2 C Þ ac surpass the equilibrium activity products ða Ce ⋅ a P Þ eq , ða Ce ⋅ a As Þ eq , and ða Ce ⋅ a 2 C Þ eq , respectively. The Brody-Flemings model modified by Clyne and Kurz [4,[34][35][36][37][38] is adopted to evaluate the solute redistribution elements during solidification, assuming limited diffusion in the solid phase and complete diffusion in the liquid phase, as elucidated in Equation ( 8)-( 14). [37] ½Ce…”

Section: Formation Mechanism Of P- As-and C-containing Inclusionsmentioning

confidence: 99%

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Effects of Cerium Content on the Nonmetallic Inclusions and Impact Toughness of Transformation‐Induced Plasticity Steel

Wang,

Zhu,

Chen

et al. 2024

steel research int.

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The effects of Ce treatment on the inclusion evolution and impact toughness of as‐cast transformation‐induced plasticity (TRIP) steel are systematically investigated by scanning electron microscope (SEM) and impact toughness testing. The results reveal that in Fe‐2Mn‐1.5Al‐1Si‐0.2C steel without Ce, the primary inclusions consist of AlN, MnS, and Al2O3. After Ce addition, the inclusions evolve into Ce‐Al‐O, Ce2O2S, CeS, and Ce2O3 inclusions. The evolution of inclusions exhibits an initial reduction in both quantity and size with increasing Ce content, followed by a subsequent increase. In cases of excessive Ce content, there is an observable rise in the overall inclusion count, marked by the emergence of CeAs, CeP, and CeC2 inclusions. The segregation model suggests that P‐containing inclusions predominantly precipitate in the late solidification process, while As‐ and C‐containing inclusions form during the solid phase. When the Ce content reaches 0.0075 wt%, the minimum values of the number density and average diameter are 96.7 mm−2 and 1.6 μm, respectively. Furthermore, the influence of the size, morphology, quantity, and type of inclusions on the impact toughness are analyzed. The highest recorded impact energy is 6.8 J with a Ce content of 0.0075 wt%.

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$$\left[\right.

…”

Section: Discussionmentioning

confidence: 99%

Section: Formation Mechanism Of P- As-and C-containing Inclusionsmentioning

confidence: 99%

Effects of Cerium Content on the Nonmetallic Inclusions and Impact Toughness of Transformation‐Induced Plasticity Steel

Wang,

Zhu,

Chen

et al. 2024

steel research int.

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“…On the other hand, the ferrite grain refinement also attracted researchers’ attention. Bhattacharya et al [ 18 ] prepared ultrafine ferrite grain microstructure (UFFG) with grain size less than 3 µm in low-carbon microalloyed steel through warm rolling followed by rapid transformation annealing (RTA) at 800–850 °C and subcritical annealing (SCA) at 600 °C. Mukherjee et al [ 19 ] conducted cold-rolling and subsequent intercritical annealing on a fibrous ferrite/martensite starting microstructure, and obtained ultrafine-grained DP (UFG-DP) steel with an average ferrite grain size of ~2.7 µm.…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Mechanical Properties of Low- and Medium-Carbon Si-Rich Low-Alloy Steels Processed by Austemping after Intercritical Annealing

et al. 2022

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In the present paper, the designed thermomechanical process was applied to prepare ferrite/bainite multiphase microstructures in Si-rich low-alloy steel with a carbon content of 0.33 wt.% (0.33C) and 0.21 wt.% (0.21C). The microstructures were analyzed by scanning electron microscope, transmission electron microscope, and electron backscatter diffraction, and the mechanical properties (tensile and impact properties) were tested. The results showed that, on the premise of obtaining 15 vol.% ferrite in both steels, the ferrite grains in the 0.33C steel were polygonal with an average grain size of 2.2 μm, recrystallized more completely. However, the ferrite grains in the 0.21C steel were mainly long strip-shaped with a width of 2–4 μm, and the recrystallization degree was poor. In addition, upon increasing the austempering temperature, bainite ferrite laths were formed in the 0.33C steel, and the thickness was in the range of 81–123 nm. The morphology of bainite ferrite in the 0.21C steel gradually changed from lath to granular. Upon increasing the austempering temperature, the tensile strength and yield strength of both steels increased and the elongation decreased slightly. The impact energy of the two steels showed different trends upon increasing the austempering temperature, in which the impact energy of the 0.33C steel increased, while that of the 0.21C steel decreased. This is due to the difference size of the martensite-austenite constituents in the two steels.

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“…Spheroidization was faster if prior to subcritical annealing, the steel was cold deformed or intercritically annealed. Bhattacharya et al [15] studied subcritical annealing of lowcarbon microalloyed steel after different sequences of hot rolling. An ultrafine grain microstructure, obtained by 80 % warm deformation followed by intercritical annealing at 800 °C for 5 min and water quenching, resulted in the optimum combination of strength and ductility.…”

Section: Introductionmentioning

confidence: 99%

Single-Step Heat Treatment for the Restoration of Mechanical Properties of Cold-Strained Mining Support Steel 31Mn4

Lojen

Mayer²,

Bončina

et al. 2020

SV-JME

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The steel 31Mn4+QT630 is used frequently for mining support arches. The supports are cold strained, first during service, and again by re-rolling prior to reinstallation, which results in strain hardening and a loss of ductility. Consequently, many of the rerolled arch-segments are not suitable for reinstallation because their mechanical properties are inadequate. The objective of this work was to assess the feasibility of restoration of the required mechanical properties by means of a cost-efficient single step heat treatment. Specimens were cold deformed to different degrees in the range 0 % to 45 % to establish the relation between the degree of cold deformation and the hardness. Differently strain hardened specimens were subjected to subcritical annealing at temperatures 450 °C to 700 °C in the duration 0.5 h to 8 h to determine a suitable time-temperature combinations. Microstructures and mechanical properties were investigated of as-received, cold strained and recrystallized specimens. Tests performed were optical microscopy, scanning electron microscopy, tensile tests, hardness measurements and Charpy impact tests. Elongation at break of the as-received material was below the requirements of the applicable standard, and its microstructure contained significant fractions of pre-eutectoid ferrite and pearlite. Upon cold straining, hardness increased by approximately 2 HV per 1 % of strain. After one-hour recrystallization at 600 °C to 620 °C, the microstructure consisted of a ferritic matrix containing evenly dispersed globular carbide particles. The original ductility was restored, while the elongation, yield strength, and hardness were higher than in the as-received condition. These results confirmed that it is feasible to restore the original mechanical properties of heavily strained profiles with an adequate single-step heat treatment. Furthermore, they indicated that it should be possible to recover the required properties of inhomogeneously strained material with the same set of well optimized heat treatment parameters. Consequently, it should be possible to increase the reuse rate and to decrease the costs for new support arches significantly.

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Processing of Ultrafine-Grained Steels by Warm Rolling and Annealing

Cited by 5 publications

References 50 publications

Effects of Cerium Content on the Nonmetallic Inclusions and Impact Toughness of Transformation‐Induced Plasticity Steel

Effects of Cerium Content on the Nonmetallic Inclusions and Impact Toughness of Transformation‐Induced Plasticity Steel

Microstructure and Mechanical Properties of Low- and Medium-Carbon Si-Rich Low-Alloy Steels Processed by Austemping after Intercritical Annealing

Single-Step Heat Treatment for the Restoration of Mechanical Properties of Cold-Strained Mining Support Steel 31Mn4

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