Prior Austenite Grain

14,000,000 Leading Edge Experts on the ideXlab platform

Scan Science and Technology

Contact Leading Edge Experts & Companies

Scan Science and Technology

Contact Leading Edge Experts & Companies

The Experts below are selected from a list of 309 Experts worldwide ranked by ideXlab platform

R.d.k. Misra - One of the best experts on this subject based on the ideXlab platform.

  • Effect of Heterogeneous Microstructure on Refining Austenite Grain Size in Low Alloy Heavy-Gage Plate
    Metals, 2020
    Co-Authors: Shengfu Yuan, Chengjia Shang, Zhenjia Xie, J.l. Wang, Longhao Zhu, Ling Yan, R.d.k. Misra
    Abstract:

    The present work introduces the role of heterogeneous microstructure in enhancing the nucleation density of reversed Austenite. It was found that the novel pre-annealing produced a heterogeneous microstructure consisting of alloying elements-enriched martensite and alloying-depleted intercritical ferrite. The shape of the martensite at the Prior Austenite Grain boundary was equiaxed and acicular at inter-laths. The equiaxed reversed Austenite had a K-S orientation with adjacent Prior Austenite Grain, and effectively refined the Prior Austenite Grain that it grew into. The alloying elements-enriched martensite provided additional nucleation sites to form equiaxed reversed Austenite at both Prior Austenite Grain boundaries and intragranular inter-lath boundaries during re-austenitization. It was revealed that Prior Austenite Grain size was refined to ~12 μm by pre-annealing and quenching, while it was ~30 μm by conventional quenching. This is a practical way of refining transformation products by refining Prior Austenite Grain size to improve the strength, ductility and low temperature toughness of heavy-gage plate steel.

  • new insights from crystallography into the effect of refining Prior Austenite Grain size on transformation phenomenon and consequent mechanical properties of ultra high strength low alloy steel
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2019
    Co-Authors: Xin Wang, Chengjia Shang, Z Q Wang, J X Zhao, Y H Jin, C S Wang, R.d.k. Misra
    Abstract:

    Abstract Based on new insights from crystallography, this study aims to establish the relationship between Prior Austenite Grain size and mechanical properties and enhance our understanding of Hall-Petch relationship. The refinement of Prior Austenite Grains was achieved by decreasing the austenitizing temperature (from 920 ℃ to 880 ℃) and quenching. In addition, samples subjected to 880 ℃ heat treatment and quenching produced a significantly higher percentage of martensite. Electron backscattered diffraction (EBSD) used to characterize the crystallographic characteristics indicated that the steel subjected to 920 ℃ heat treatment and quenched had larger Prior Austenite Grains, belonging to the transformation of Bain group. After 880 ℃ heat treatment and quenching, the Prior Austenite Grains were smaller and more uniform, which belonged to the transformation dominated by CP (close-packed plane) group. The transformation from Bain group to CP group was related to transformation driving force, and resulted in increase in the density of high angle Grain boundaries (DHAGBs). Using thermal expansion approach to measure the initial martensite transformation temperature (Ms temperature), the samples heat treated and quenched at 920 ℃ and 880 ℃ showed Ms temperature of 400 ℃ and 427 ℃, respectively, implying that the phase transformation driving force was increased by refining the Prior Austenite Grain. Charpy impact energy test at −40 ℃ suggested that after 880 ℃ heat treatment and quenching, the Charpy energy increased from 46 J to 92 J, consistent with the results of EBSD.

  • Improvement of strength-toughness combination in austempered low carbon bainitic steel: The key role of refining Prior Austenite Grain size
    Journal of Alloys and Compounds, 2017
    Co-Authors: H.f. Lan, C.l. Qiu, R.d.k. Misra
    Abstract:

    Abstract A low carbon bainitic steel with ultrahigh strength of ∼1650 MPa and elongation and toughness of ∼16% and ∼72 J/cm2 respectively, was obtained through austempering. The resulting microstructure and mechanical properties for varying Prior Austenite Grain size (PAGS) are described. The refinement of the PAGS resulted in finer packet/block size, higher volume fraction and higher stability of retained Austenite. The coalescence of bainitic laths was effectively hindered when the Prior Austenite Grain size (PAGS) was refined to ∼10 μm. On the other hand, the coalescence of bainitic laths with crystallographically homogeneous characteristic was accompanied by disappearance of film-like retained Austenite and crack can propagate without inhibition, which is detrimental to toughness. Eliminating the coalescence of bainite and increasing the volume fraction of retained Austenite and its stability by means of refining PAGS contributed to ultrahigh strength – high ductility and toughness combination.

  • influence of Prior Austenite Grain size on martensite Austenite constituent and toughness in the heat affected zone of 700mpa high strength linepipe steel
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014
    Co-Authors: S V Subramanian, Chengjia Shang, R.d.k. Misra
    Abstract:

    Abstract Structure–mechanical property relationship studies were carried out on Gleeble simulated intercritically reheated coarse-Grained heat affected zone (ICCGHAZ) of 700 MPa linepipe steel microalloyed with Nb. The design of experiments was aimed at varying reheat temperature in the first pass to obtain different coarse Grain size in the HAZ. This enabled the study of the effect of Prior Austenite Grain size on martensite–Austenite (M–A) constituent during the second pass reheating and its consequent influence on impact toughness. We elucidate here the role of phase transformation and the fraction, size, shape, distribution, and carbon content of M–A constituent on impact toughness. The data suggests that the fraction of M–A constituent is not influenced by Grain size, but the size of M–A constituent is influenced by the Prior Austenite Grain size, which consequently governs toughness. Coarse Austenite Grain size increases the size of M–A constituent and lowers the HAZ toughness. Coarse Austenite Grain associated with coarse M–A constituent along Grain boundary is the dominant factor in promoting brittle fracture. The combination of fine Prior Austenite Grain size and smaller M–A constituent is favorable in obtaining high toughness. Good toughness is obtained on refining the Prior Austenite Grain size in the CGHAZ during first pass and hence ICCGHAZ in the second pass.

  • Influence of Prior Austenite Grain size on martensite–Austenite constituent and toughness in the heat affected zone of 700MPa high strength linepipe steel
    Materials Science and Engineering: A, 2014
    Co-Authors: S V Subramanian, Chengjia Shang, R.d.k. Misra
    Abstract:

    Abstract Structure–mechanical property relationship studies were carried out on Gleeble simulated intercritically reheated coarse-Grained heat affected zone (ICCGHAZ) of 700 MPa linepipe steel microalloyed with Nb. The design of experiments was aimed at varying reheat temperature in the first pass to obtain different coarse Grain size in the HAZ. This enabled the study of the effect of Prior Austenite Grain size on martensite–Austenite (M–A) constituent during the second pass reheating and its consequent influence on impact toughness. We elucidate here the role of phase transformation and the fraction, size, shape, distribution, and carbon content of M–A constituent on impact toughness. The data suggests that the fraction of M–A constituent is not influenced by Grain size, but the size of M–A constituent is influenced by the Prior Austenite Grain size, which consequently governs toughness. Coarse Austenite Grain size increases the size of M–A constituent and lowers the HAZ toughness. Coarse Austenite Grain associated with coarse M–A constituent along Grain boundary is the dominant factor in promoting brittle fracture. The combination of fine Prior Austenite Grain size and smaller M–A constituent is favorable in obtaining high toughness. Good toughness is obtained on refining the Prior Austenite Grain size in the CGHAZ during first pass and hence ICCGHAZ in the second pass.

Chengjia Shang - One of the best experts on this subject based on the ideXlab platform.

  • Effect of Heterogeneous Microstructure on Refining Austenite Grain Size in Low Alloy Heavy-Gage Plate
    Metals, 2020
    Co-Authors: Shengfu Yuan, Chengjia Shang, Zhenjia Xie, J.l. Wang, Longhao Zhu, Ling Yan, R.d.k. Misra
    Abstract:

    The present work introduces the role of heterogeneous microstructure in enhancing the nucleation density of reversed Austenite. It was found that the novel pre-annealing produced a heterogeneous microstructure consisting of alloying elements-enriched martensite and alloying-depleted intercritical ferrite. The shape of the martensite at the Prior Austenite Grain boundary was equiaxed and acicular at inter-laths. The equiaxed reversed Austenite had a K-S orientation with adjacent Prior Austenite Grain, and effectively refined the Prior Austenite Grain that it grew into. The alloying elements-enriched martensite provided additional nucleation sites to form equiaxed reversed Austenite at both Prior Austenite Grain boundaries and intragranular inter-lath boundaries during re-austenitization. It was revealed that Prior Austenite Grain size was refined to ~12 μm by pre-annealing and quenching, while it was ~30 μm by conventional quenching. This is a practical way of refining transformation products by refining Prior Austenite Grain size to improve the strength, ductility and low temperature toughness of heavy-gage plate steel.

  • new insights from crystallography into the effect of refining Prior Austenite Grain size on transformation phenomenon and consequent mechanical properties of ultra high strength low alloy steel
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2019
    Co-Authors: Xin Wang, Chengjia Shang, Z Q Wang, J X Zhao, Y H Jin, C S Wang, R.d.k. Misra
    Abstract:

    Abstract Based on new insights from crystallography, this study aims to establish the relationship between Prior Austenite Grain size and mechanical properties and enhance our understanding of Hall-Petch relationship. The refinement of Prior Austenite Grains was achieved by decreasing the austenitizing temperature (from 920 ℃ to 880 ℃) and quenching. In addition, samples subjected to 880 ℃ heat treatment and quenching produced a significantly higher percentage of martensite. Electron backscattered diffraction (EBSD) used to characterize the crystallographic characteristics indicated that the steel subjected to 920 ℃ heat treatment and quenched had larger Prior Austenite Grains, belonging to the transformation of Bain group. After 880 ℃ heat treatment and quenching, the Prior Austenite Grains were smaller and more uniform, which belonged to the transformation dominated by CP (close-packed plane) group. The transformation from Bain group to CP group was related to transformation driving force, and resulted in increase in the density of high angle Grain boundaries (DHAGBs). Using thermal expansion approach to measure the initial martensite transformation temperature (Ms temperature), the samples heat treated and quenched at 920 ℃ and 880 ℃ showed Ms temperature of 400 ℃ and 427 ℃, respectively, implying that the phase transformation driving force was increased by refining the Prior Austenite Grain. Charpy impact energy test at −40 ℃ suggested that after 880 ℃ heat treatment and quenching, the Charpy energy increased from 46 J to 92 J, consistent with the results of EBSD.

  • influence of Prior Austenite Grain size on martensite Austenite constituent and toughness in the heat affected zone of 700mpa high strength linepipe steel
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014
    Co-Authors: S V Subramanian, Chengjia Shang, R.d.k. Misra
    Abstract:

    Abstract Structure–mechanical property relationship studies were carried out on Gleeble simulated intercritically reheated coarse-Grained heat affected zone (ICCGHAZ) of 700 MPa linepipe steel microalloyed with Nb. The design of experiments was aimed at varying reheat temperature in the first pass to obtain different coarse Grain size in the HAZ. This enabled the study of the effect of Prior Austenite Grain size on martensite–Austenite (M–A) constituent during the second pass reheating and its consequent influence on impact toughness. We elucidate here the role of phase transformation and the fraction, size, shape, distribution, and carbon content of M–A constituent on impact toughness. The data suggests that the fraction of M–A constituent is not influenced by Grain size, but the size of M–A constituent is influenced by the Prior Austenite Grain size, which consequently governs toughness. Coarse Austenite Grain size increases the size of M–A constituent and lowers the HAZ toughness. Coarse Austenite Grain associated with coarse M–A constituent along Grain boundary is the dominant factor in promoting brittle fracture. The combination of fine Prior Austenite Grain size and smaller M–A constituent is favorable in obtaining high toughness. Good toughness is obtained on refining the Prior Austenite Grain size in the CGHAZ during first pass and hence ICCGHAZ in the second pass.

  • Influence of Prior Austenite Grain size on martensite–Austenite constituent and toughness in the heat affected zone of 700MPa high strength linepipe steel
    Materials Science and Engineering: A, 2014
    Co-Authors: S V Subramanian, Chengjia Shang, R.d.k. Misra
    Abstract:

    Abstract Structure–mechanical property relationship studies were carried out on Gleeble simulated intercritically reheated coarse-Grained heat affected zone (ICCGHAZ) of 700 MPa linepipe steel microalloyed with Nb. The design of experiments was aimed at varying reheat temperature in the first pass to obtain different coarse Grain size in the HAZ. This enabled the study of the effect of Prior Austenite Grain size on martensite–Austenite (M–A) constituent during the second pass reheating and its consequent influence on impact toughness. We elucidate here the role of phase transformation and the fraction, size, shape, distribution, and carbon content of M–A constituent on impact toughness. The data suggests that the fraction of M–A constituent is not influenced by Grain size, but the size of M–A constituent is influenced by the Prior Austenite Grain size, which consequently governs toughness. Coarse Austenite Grain size increases the size of M–A constituent and lowers the HAZ toughness. Coarse Austenite Grain associated with coarse M–A constituent along Grain boundary is the dominant factor in promoting brittle fracture. The combination of fine Prior Austenite Grain size and smaller M–A constituent is favorable in obtaining high toughness. Good toughness is obtained on refining the Prior Austenite Grain size in the CGHAZ during first pass and hence ICCGHAZ in the second pass.

  • Refinement of Prior Austenite Grain in Advanced Pipeline Steel
    Advanced Steels, 2011
    Co-Authors: Chengjia Shang, Chengliang Miao
    Abstract:

    A series of fundamental and applied investigations were carried out to develop high grade pipeline steel with high Mn high Nb design, and it mostly focused on that the static and dynamic recrystallization behaviors of high Mn high Nb pipeline steel. Various experimental methods were adopted, which include stress relaxation tests, physical metallurgical modeling analysis, the etching of Prior Austenite Grains and TEM observation of precipitates. According to the results, new control rolling technology is bring forward under high Mn high Nb approach, as a consequence, fine and homogeneous Prior Austenite Grains can be generated by complete static recrystallization Prior to finish rolling, and the coarsening can be suppressed largely by drag effect, through proper finish rolling process, Prior Austenite Grain will be flatten fully and uniformly to higher flow stress or Sv, and the mixed Grains structure caused by partial dynamic recrystallization may be avoided. The physical metallurgy principle for refinement of Prior Austenite Grain through rough rolling and pancake through finish rolling can be adopted for refinement the Austenite Grain in high Mn high Nb structural steel.

Indradev Samajdar - One of the best experts on this subject based on the ideXlab platform.

  • Effect of Zener–Holloman Parameter on the Prior Austenite Grain size in a 12Cr-10Ni Precipitation-Hardenable Stainless Steel
    Journal of Materials Engineering and Performance, 2018
    Co-Authors: C. R. Anoop, Aditya Prakash, S.v.s. Narayana Murty, Indradev Samajdar
    Abstract:

    Hot isothermal plane strain compression (PSC) tests were carried out on a 12Cr-10Ni martensitic precipitation-hardenable (PH) stainless steel, in the temperature range of 750-1050 °C, to study microstructural evolution during large strain deformation. The nature of stress–strain curves varies with Zener–Holloman parameter (Z) with specimens deformed at high Z showing steady-state behavior and those deformed at lower Z showing flow softening. Prior Austenite Grain size (PAGS), d, exhibited a strong correlation to Z showing a bilinear behavior represented as: d = (1803.9)Z−0.094 for high Z deformation and d = (1456.2)Z−0.058 for low Z deformation. Based on the above study, it is recommended to thermomechanically process 12Cr-10Ni steel at Z ≥ 1022 for obtaining products with good strength–toughness balance.

  • effect of zener holloman parameter on the Prior Austenite Grain size in a 12cr 10ni precipitation hardenable stainless steel
    Journal of Materials Engineering and Performance, 2018
    Co-Authors: C. R. Anoop, Aditya Prakash, S Narayana V S Murty, Indradev Samajdar
    Abstract:

    Hot isothermal plane strain compression (PSC) tests were carried out on a 12Cr-10Ni martensitic precipitation-hardenable (PH) stainless steel, in the temperature range of 750-1050 °C, to study microstructural evolution during large strain deformation. The nature of stress–strain curves varies with Zener–Holloman parameter (Z) with specimens deformed at high Z showing steady-state behavior and those deformed at lower Z showing flow softening. Prior Austenite Grain size (PAGS), d, exhibited a strong correlation to Z showing a bilinear behavior represented as: d = (1803.9)Z−0.094 for high Z deformation and d = (1456.2)Z−0.058 for low Z deformation. Based on the above study, it is recommended to thermomechanically process 12Cr-10Ni steel at Z ≥ 1022 for obtaining products with good strength–toughness balance.

N. Ridley - One of the best experts on this subject based on the ideXlab platform.

  • The effect of austenitising temperature on Prior Austenite Grain size in a low-alloy steel
    Materials Science and Engineering: A, 2008
    Co-Authors: Stergios Maropoulos, Stefanos Karagiannis, N. Ridley
    Abstract:

    Abstract The effect of varying normalising and hardening temperatures on the Prior Austenite Grain size in a low-alloy Cr–Mo–Ni–V steel has been examined. An initial relative insensitivity of Grain size to increasing austenitising temperature was observed followed by a sudden growth of Grains at approximately 1000 °C. A detailed study of the precipitates in the steel showed the presence of a bimodal size distribution of vanadium carbides. The Grain size increase is attributed to a decrease in volume fraction and an increase in size of V4C3 particles with increasing temperature.

  • Factors affecting Prior Austenite Grain size in low alloy steel
    Journal of Materials Science, 2006
    Co-Authors: Stergios Maropoulos, Stefanos Karagiannis, N. Ridley
    Abstract:

    The effect of varying normalising and hardening temperatures on the Prior Austenite Grain size in a low alloy Cr–Mo–Ni–V steel has been examined. An initial relative insensitivity of Grain size to increasing austenitising temperature was observed followed by a sudden growth of Grains at approximately 1000 °C. A detailed study of the precipitates in the steel showed the presence of a bimodal size distribution of vanadium carbides. The Grain size increase is attributed to a decrease in volume fraction and an increase in size of V4C3 particles with increasing temperature.

S V Subramanian - One of the best experts on this subject based on the ideXlab platform.

  • influence of Prior Austenite Grain size on martensite Austenite constituent and toughness in the heat affected zone of 700mpa high strength linepipe steel
    Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2014
    Co-Authors: S V Subramanian, Chengjia Shang, R.d.k. Misra
    Abstract:

    Abstract Structure–mechanical property relationship studies were carried out on Gleeble simulated intercritically reheated coarse-Grained heat affected zone (ICCGHAZ) of 700 MPa linepipe steel microalloyed with Nb. The design of experiments was aimed at varying reheat temperature in the first pass to obtain different coarse Grain size in the HAZ. This enabled the study of the effect of Prior Austenite Grain size on martensite–Austenite (M–A) constituent during the second pass reheating and its consequent influence on impact toughness. We elucidate here the role of phase transformation and the fraction, size, shape, distribution, and carbon content of M–A constituent on impact toughness. The data suggests that the fraction of M–A constituent is not influenced by Grain size, but the size of M–A constituent is influenced by the Prior Austenite Grain size, which consequently governs toughness. Coarse Austenite Grain size increases the size of M–A constituent and lowers the HAZ toughness. Coarse Austenite Grain associated with coarse M–A constituent along Grain boundary is the dominant factor in promoting brittle fracture. The combination of fine Prior Austenite Grain size and smaller M–A constituent is favorable in obtaining high toughness. Good toughness is obtained on refining the Prior Austenite Grain size in the CGHAZ during first pass and hence ICCGHAZ in the second pass.

  • Influence of Prior Austenite Grain size on martensite–Austenite constituent and toughness in the heat affected zone of 700MPa high strength linepipe steel
    Materials Science and Engineering: A, 2014
    Co-Authors: S V Subramanian, Chengjia Shang, R.d.k. Misra
    Abstract:

    Abstract Structure–mechanical property relationship studies were carried out on Gleeble simulated intercritically reheated coarse-Grained heat affected zone (ICCGHAZ) of 700 MPa linepipe steel microalloyed with Nb. The design of experiments was aimed at varying reheat temperature in the first pass to obtain different coarse Grain size in the HAZ. This enabled the study of the effect of Prior Austenite Grain size on martensite–Austenite (M–A) constituent during the second pass reheating and its consequent influence on impact toughness. We elucidate here the role of phase transformation and the fraction, size, shape, distribution, and carbon content of M–A constituent on impact toughness. The data suggests that the fraction of M–A constituent is not influenced by Grain size, but the size of M–A constituent is influenced by the Prior Austenite Grain size, which consequently governs toughness. Coarse Austenite Grain size increases the size of M–A constituent and lowers the HAZ toughness. Coarse Austenite Grain associated with coarse M–A constituent along Grain boundary is the dominant factor in promoting brittle fracture. The combination of fine Prior Austenite Grain size and smaller M–A constituent is favorable in obtaining high toughness. Good toughness is obtained on refining the Prior Austenite Grain size in the CGHAZ during first pass and hence ICCGHAZ in the second pass.