Effect of Intercritical Austenitizing Temperature during Quenching–Intercritical Quenching–Tempering Process on Toughness of 25Mn2Si2Cr Bainitic Steel

Li, Ji; Tan, Zhunli; Zhang, Min; Gao, Guhui; Misra, R.D.K.; Bai, Bin

doi:10.1002/srin.201800573

Cited by 12 publications

(13 citation statements)

References 37 publications

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“…The stored energy of the larger deformation inside the material will increase continuously. Under high energy impact, austenite nucleation may occur at potential nucleation sites such as grain boundaries, dislocations and vacancies (dynamic recrystallization of austenite) [28,29]. Figure 8 shows the SEM micrographs with different degrees of deformation.…”

Section: Microstructurementioning

confidence: 99%

Low Temperature Deformation Induced Microstructure Refinement and Consequent Ultrahigh Toughness of a 20Mn2SiCrNi Bainitic Steel

Tian

Tan

et al. 2019

Metals

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In this paper, we have studied the influence of deformation on the microstructure and mechanical properties of 20Mn2SiCrNi bainitic high strength steel processed through a hot rolling route. Simulation of different temperatures and degrees of deformation was carried out via Gleeble-1500. The study suggested that grain size is refined when the deformation is carried out at lower temperature (> Ac3). When the degree of deformation was increased from 20% to 60%, grain size and microstructure were both refined and the size of retained austenite was reduced. The tensile strength increased from 1345 MPa to 1432 MPa. The impact toughness increased from 115 J/cm2 to 210 J/cm2 at room temperature, from 63 J/cm2 to 142 J/cm2 at −40 °C. Furthermore, it was observed that the microstructure after air cooling was composed of granular bainite (GB), lath bainite (LB) and martensite/austenite (MA) island for different deformation conditions. The study reveals that the impact toughness of 20Mn2SiCrNi bainitic high strength steel can be increased by increasing the degree of deformation.

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Section: Microstructurementioning

confidence: 99%

Low Temperature Deformation Induced Microstructure Refinement and Consequent Ultrahigh Toughness of a 20Mn2SiCrNi Bainitic Steel

Tian

Tan

et al. 2019

Metals

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“…Fine cementite particles precipitated during tempering at 450 °C, and the steel exhibited a good match of strength and plasticity. Li et al [ 9 ] introduced critical quenching between the traditional quenching and tempering processes. When the critical quenching temperature increased, austenite nucleated along with the martensite lath and was transformed from acicular to equiaxed.…”

Section: Introductionmentioning

confidence: 99%

Effect of Quenching and Tempering Temperatures on Microstructure and Properties of Ultrahigh Strength Cast Steel

Zhou

Zhao

Dong

et al. 2022

steel research int.

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Low‐alloy cast steel with ultrahigh strength is produced by a combination of normalizing and reheating, followed by water quenching and high‐temperature tempering. The cast steel quenched at 1000 °C for 30 min and tempered at 550 °C for 120 min exhibits superior tensile ductility. More precisely, the tensile strength is 1683.5 MPa, yield strength is 1635.3 MPa, elongation is 12.0%, and microhardness is 500.3 HV. The microstructure is composed of martensite lath + ferrite + M23C6 carbide. The strengthening mechanisms of the steel are mainly precipitation, grain refinement, and dislocation strengthening. When the quenching temperature is increased from 950 to 1000 °C, the M3C carbides precipitated between the martensite lath are transformed from short rod‐like to spherical shapes, which improves the plasticity of the steel. When the tempering temperature is increased from 550 to 630 °C, the number and size of the carbides also increase. The M23C6 carbides interact with the dislocations. M23C6 carbides play a crucial role in the precipitation strengthening and efficiently improve the strength of the steel. The fracture is changed from a mixed ductile and brittle fracture to a ductile fracture.

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“…In addition, the refinement of microstructure arises from the reduction of PAGS, resulting in an increase in the toughness without loss of strength. [ 14 ] Similarly, Lan et al pointed out that the refinement of PAGS contributes to the formation of finer packet/block size of bainite, thereby significantly improving the combination of strength and toughness. [ 15 ] Furthermore, Tian et al investigated the effect of austenitization temperature on bainite transformation below M s temperature.…”

Section: Introductionmentioning

confidence: 99%

Enhanced Strength and Toughness of Low‐Carbon Bainitic Steel by Refining Prior Austenite Grains and Austempering Below M_s

Yao

Lan

Tao

et al. 2021

steel research int.

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Austempering is conducted below and above martensite start temperature (Ms) at the fine and coarse prior austenite grain size (PAGS), respectively, in a low‐carbon bainitic steel, and the relationship between multiphase microstructure and mechanical properties is investigated. The study indicates that refinement of bainite laths can be obtained by decreasing the PAGS and/or austempering temperature from above to below Ms. The former reduces bainite content, and increases the volume fraction of retained austenite (RA), thereby obtaining higher uniform elongation and strain hardening exponent. However, the latter effectively decreases the size and amount of blocky RA, as well as bainite content and conversely increases the ratio of volume fraction of film RA to that of blocky RA, which leads to significant improvement in yield strength and impact toughness. In addition, the variant selection is relatively weak with the decrease in the PAGS and austempering temperature, which has a beneficial effect on toughness. Furthermore, an outstanding combination of mechanical properties (1070 MPa yield strength, 1466 MPa tensile strength, total elongation of 11.68%, and V‐notch impact toughness at 20 and −40 °C of 78 and 44 J cm−2, respectively) is achieved by austempering below Ms in the finer PAGS.

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Effect of Intercritical Austenitizing Temperature during Quenching–Intercritical Quenching–Tempering Process on Toughness of 25Mn2Si2Cr Bainitic Steel

Cited by 12 publications

References 37 publications

Low Temperature Deformation Induced Microstructure Refinement and Consequent Ultrahigh Toughness of a 20Mn2SiCrNi Bainitic Steel

Low Temperature Deformation Induced Microstructure Refinement and Consequent Ultrahigh Toughness of a 20Mn2SiCrNi Bainitic Steel

Effect of Quenching and Tempering Temperatures on Microstructure and Properties of Ultrahigh Strength Cast Steel

Enhanced Strength and Toughness of Low‐Carbon Bainitic Steel by Refining Prior Austenite Grains and Austempering Below M_s

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Effect of Intercritical Austenitizing Temperature during Quenching–Intercritical Quenching–Tempering Process on Toughness of 25Mn2Si2Cr Bainitic Steel

Cited by 12 publications

References 37 publications

Low Temperature Deformation Induced Microstructure Refinement and Consequent Ultrahigh Toughness of a 20Mn2SiCrNi Bainitic Steel

Low Temperature Deformation Induced Microstructure Refinement and Consequent Ultrahigh Toughness of a 20Mn2SiCrNi Bainitic Steel

Effect of Quenching and Tempering Temperatures on Microstructure and Properties of Ultrahigh Strength Cast Steel

Enhanced Strength and Toughness of Low‐Carbon Bainitic Steel by Refining Prior Austenite Grains and Austempering Below Ms

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Enhanced Strength and Toughness of Low‐Carbon Bainitic Steel by Refining Prior Austenite Grains and Austempering Below M_s