The Experts below are selected from a list of 249 Experts worldwide ranked by ideXlab platform

Guodong Wang - One of the best experts on this subject based on the ideXlab platform.

  • Relationship Between Impact Toughness and Microstructure for the As-Rolled and Simulated HAZ of Low-Carbon Steel Containing Ti-Ca Oxide Particles
    Metallurgical and Materials Transactions A, 2020
    Co-Authors: Xin Wang, Chao Wang, Jian Kang, Guodong Wang, Devesh Misra, Guo Yuan
    Abstract:

    In this study, the microstructure and mechanical properties of Ti-Ca Deoxidized low-carbon Steel compared with Al-Ca Deoxidized Steel were investigated. Hot rolling experiment and high heat input welding heat-affected zone (HAZ) simulation were carried out. In situ transformation behavior and crack propagation during impact in simulated HAZ were analyzed. The results indicated that interlocking acicular ferrite (AF) was the dominant microstructure after Ti-Ca deoxidation treatment, and TiOx-CaO-Al2O3-MnS-type complex inclusion with maximum proportion was effective for AF nucleation. However, Al2O3-CaO-(Ca, Mn)S-type inclusion that was dominant in Al-Ca Steel exhibited significantly lower ability for AF nucleation. The high ratio of high-angle grain boundaries/low-angle grain boundaries in AF microstructure hindered the initiation and propagation of crack. The stress concentration in the vicinity of crack tip can be released because of superior deformability of AF structure as compared to bainite packets. By introducing Ti-Ca oxide particles, the mechanical properties of hot-rolled Steel plate and HAZ, particularly impact toughness, were significantly enhanced because of the formation of fine AF.

  • An in-situ microscopy study on nucleation and growth of acicular ferrite in Ti-Ca-Zr Deoxidized low-carbon Steel
    Materials Characterization, 2020
    Co-Authors: Xin Wang, Chao Wang, Jian Kang, Guo Yuan, R.d.k. Misra, Guodong Wang
    Abstract:

    Abstract We describe here an in-situ microscopy study on the nucleation and growth of acicular ferrite in Ti-Ca-Zr Deoxidized low-carbon Steel as a function of cooling rate. The study indicated the starting transformation temperature of acicular ferrite decreased with increasing cooling rate. Moreover, the average growth rate of acicular ferrite was increased from ~2.2 μm/s to ~14.4 μm/s with the increase of cooling rate from 2 °C/s to 15 °C/s. In Ti-Ca-Zr Deoxidized Steel, (Ti, Ca, Zr, Al)-O-Mn-S oxide inclusions effectively promoted the formation of intragranular acicular ferrite. A significantly high proportion of acicular ferrite was characterized by high angle grain boundaries and reduced grain size. When the cooling rate was low at 5 °C/s, the proportion of acicular ferrite was high at ~85%, with ~48% high angle grain boundaries and small average grain size of ~2.7 μm. Additionally, MnS precipitated in the vicinity of (Ti, Ca, Zr, Al)-O-Mn-S oxide particles, which promoted the nucleation of acicular ferrite.

  • Microstructure and mechanical properties of hot-rolled low-carbon Steel containing Ti–Ca oxide particles: a comparison between base metal and HAZ
    Journal of Iron and Steel Research International, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    The effect of inclusion-induced nucleation on hot-rolled Steel base metal was evaluated in comparison with welding heat-affected zone (HAZ). Microstructure and mechanical properties of hot-rolled low-carbon Steel containing Ti–Ca oxide particles were studied. The results showed that inclusions in Ti–Ca Deoxidized Steel distributed dispersely and were effective for intragranular acicular ferrite nucleation. Under hot rolling and controlled cooling conditions, microstructure in Steel base metal was significantly refined and mainly consisted of acicular ferrite and intragranular bainite, which exhibited higher strength and excellent toughness. The microstructural evolution behavior followed the process that acicular ferrite plates divided the austenite grain, intragranular bainite packets formed between interlocking acicular ferrite plates, and the remaining austenite decomposed into fine polygonal ferrite grains. The resultant complex microstructure improved the impact toughness significantly. By comparison, in HAZ microstructure, laminar grain boundary ferrite having similar crystallography orientation showed adverse effect on toughness.

  • Effect of Thermomechanical Treatment on Acicular Ferrite Formation in Ti–Ca Deoxidized Low Carbon Steel
    Metals, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    Transformation behaviors and mechanical properties under thermomechanical treatment conditions of Ti–Ca Deoxidized low carbon Steel were studied in comparison to Al–Ca treated Steel. A thermomechanical simulation and a hot rolling experiment were carried out. Inclusions and microstructures were characterized, and the transformation mechanism was analyzed. The results indicated that typical inclusions in Ti–Ca Deoxidized Steel were TiOx-MnS-Al2O3-CaO, TiOx-MnO-Al2O3-CaO, and TiOx-MnS, which were effective for acicular ferrite (AF) nucleation. Acicular ferrite formation temperature decreased with an increase in cooling rate. A fine AF dominant microstructure was formed under a high driving force for the transformation from austenite to ferrite at lower temperatures. A high deformation of 43–65% discouraged the formation of acicular ferrite because of the increase in austenite grain boundaries serving as nucleation sites. The fraction of high-angled grain boundaries that acted as obstacles to cleavage cracks was the highest in the sample cooled at 5 °C/s because of full AF structure formation. The hardness increased significantly as the cooling rate increased from 2 to 15 °C/s, whereas it decreased under the condition of deformation because of the formation of (quasi-)polygonal ferrite. By applying accelerated water cooling, the mechanical properties, particularly impact toughness, were significantly improved as a result of fine AF microstructure formation.

  • Effect of Thermomechanical Treatment on Acicular Ferrite Formation in Ti–Ca Deoxidized Low Carbon Steel
    MDPI AG, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    Transformation behaviors and mechanical properties under thermomechanical treatment conditions of Ti–Ca Deoxidized low carbon Steel were studied in comparison to Al–Ca treated Steel. A thermomechanical simulation and a hot rolling experiment were carried out. Inclusions and microstructures were characterized, and the transformation mechanism was analyzed. The results indicated that typical inclusions in Ti–Ca Deoxidized Steel were TiOx-MnS-Al2O3-CaO, TiOx-MnO-Al2O3-CaO, and TiOx-MnS, which were effective for acicular ferrite (AF) nucleation. Acicular ferrite formation temperature decreased with an increase in cooling rate. A fine AF dominant microstructure was formed under a high driving force for the transformation from austenite to ferrite at lower temperatures. A high deformation of 43–65% discouraged the formation of acicular ferrite because of the increase in austenite grain boundaries serving as nucleation sites. The fraction of high-angled grain boundaries that acted as obstacles to cleavage cracks was the highest in the sample cooled at 5 °C/s because of full AF structure formation. The hardness increased significantly as the cooling rate increased from 2 to 15 °C/s, whereas it decreased under the condition of deformation because of the formation of (quasi-)polygonal ferrite. By applying accelerated water cooling, the mechanical properties, particularly impact toughness, were significantly improved as a result of fine AF microstructure formation

Chao Wang - One of the best experts on this subject based on the ideXlab platform.

  • Relationship Between Impact Toughness and Microstructure for the As-Rolled and Simulated HAZ of Low-Carbon Steel Containing Ti-Ca Oxide Particles
    Metallurgical and Materials Transactions A, 2020
    Co-Authors: Xin Wang, Chao Wang, Jian Kang, Guodong Wang, Devesh Misra, Guo Yuan
    Abstract:

    In this study, the microstructure and mechanical properties of Ti-Ca Deoxidized low-carbon Steel compared with Al-Ca Deoxidized Steel were investigated. Hot rolling experiment and high heat input welding heat-affected zone (HAZ) simulation were carried out. In situ transformation behavior and crack propagation during impact in simulated HAZ were analyzed. The results indicated that interlocking acicular ferrite (AF) was the dominant microstructure after Ti-Ca deoxidation treatment, and TiOx-CaO-Al2O3-MnS-type complex inclusion with maximum proportion was effective for AF nucleation. However, Al2O3-CaO-(Ca, Mn)S-type inclusion that was dominant in Al-Ca Steel exhibited significantly lower ability for AF nucleation. The high ratio of high-angle grain boundaries/low-angle grain boundaries in AF microstructure hindered the initiation and propagation of crack. The stress concentration in the vicinity of crack tip can be released because of superior deformability of AF structure as compared to bainite packets. By introducing Ti-Ca oxide particles, the mechanical properties of hot-rolled Steel plate and HAZ, particularly impact toughness, were significantly enhanced because of the formation of fine AF.

  • An in-situ microscopy study on nucleation and growth of acicular ferrite in Ti-Ca-Zr Deoxidized low-carbon Steel
    Materials Characterization, 2020
    Co-Authors: Xin Wang, Chao Wang, Jian Kang, Guo Yuan, R.d.k. Misra, Guodong Wang
    Abstract:

    Abstract We describe here an in-situ microscopy study on the nucleation and growth of acicular ferrite in Ti-Ca-Zr Deoxidized low-carbon Steel as a function of cooling rate. The study indicated the starting transformation temperature of acicular ferrite decreased with increasing cooling rate. Moreover, the average growth rate of acicular ferrite was increased from ~2.2 μm/s to ~14.4 μm/s with the increase of cooling rate from 2 °C/s to 15 °C/s. In Ti-Ca-Zr Deoxidized Steel, (Ti, Ca, Zr, Al)-O-Mn-S oxide inclusions effectively promoted the formation of intragranular acicular ferrite. A significantly high proportion of acicular ferrite was characterized by high angle grain boundaries and reduced grain size. When the cooling rate was low at 5 °C/s, the proportion of acicular ferrite was high at ~85%, with ~48% high angle grain boundaries and small average grain size of ~2.7 μm. Additionally, MnS precipitated in the vicinity of (Ti, Ca, Zr, Al)-O-Mn-S oxide particles, which promoted the nucleation of acicular ferrite.

  • Microstructure and mechanical properties of hot-rolled low-carbon Steel containing Ti–Ca oxide particles: a comparison between base metal and HAZ
    Journal of Iron and Steel Research International, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    The effect of inclusion-induced nucleation on hot-rolled Steel base metal was evaluated in comparison with welding heat-affected zone (HAZ). Microstructure and mechanical properties of hot-rolled low-carbon Steel containing Ti–Ca oxide particles were studied. The results showed that inclusions in Ti–Ca Deoxidized Steel distributed dispersely and were effective for intragranular acicular ferrite nucleation. Under hot rolling and controlled cooling conditions, microstructure in Steel base metal was significantly refined and mainly consisted of acicular ferrite and intragranular bainite, which exhibited higher strength and excellent toughness. The microstructural evolution behavior followed the process that acicular ferrite plates divided the austenite grain, intragranular bainite packets formed between interlocking acicular ferrite plates, and the remaining austenite decomposed into fine polygonal ferrite grains. The resultant complex microstructure improved the impact toughness significantly. By comparison, in HAZ microstructure, laminar grain boundary ferrite having similar crystallography orientation showed adverse effect on toughness.

  • Effect of Thermomechanical Treatment on Acicular Ferrite Formation in Ti–Ca Deoxidized Low Carbon Steel
    Metals, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    Transformation behaviors and mechanical properties under thermomechanical treatment conditions of Ti–Ca Deoxidized low carbon Steel were studied in comparison to Al–Ca treated Steel. A thermomechanical simulation and a hot rolling experiment were carried out. Inclusions and microstructures were characterized, and the transformation mechanism was analyzed. The results indicated that typical inclusions in Ti–Ca Deoxidized Steel were TiOx-MnS-Al2O3-CaO, TiOx-MnO-Al2O3-CaO, and TiOx-MnS, which were effective for acicular ferrite (AF) nucleation. Acicular ferrite formation temperature decreased with an increase in cooling rate. A fine AF dominant microstructure was formed under a high driving force for the transformation from austenite to ferrite at lower temperatures. A high deformation of 43–65% discouraged the formation of acicular ferrite because of the increase in austenite grain boundaries serving as nucleation sites. The fraction of high-angled grain boundaries that acted as obstacles to cleavage cracks was the highest in the sample cooled at 5 °C/s because of full AF structure formation. The hardness increased significantly as the cooling rate increased from 2 to 15 °C/s, whereas it decreased under the condition of deformation because of the formation of (quasi-)polygonal ferrite. By applying accelerated water cooling, the mechanical properties, particularly impact toughness, were significantly improved as a result of fine AF microstructure formation.

  • Effect of Thermomechanical Treatment on Acicular Ferrite Formation in Ti–Ca Deoxidized Low Carbon Steel
    MDPI AG, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    Transformation behaviors and mechanical properties under thermomechanical treatment conditions of Ti–Ca Deoxidized low carbon Steel were studied in comparison to Al–Ca treated Steel. A thermomechanical simulation and a hot rolling experiment were carried out. Inclusions and microstructures were characterized, and the transformation mechanism was analyzed. The results indicated that typical inclusions in Ti–Ca Deoxidized Steel were TiOx-MnS-Al2O3-CaO, TiOx-MnO-Al2O3-CaO, and TiOx-MnS, which were effective for acicular ferrite (AF) nucleation. Acicular ferrite formation temperature decreased with an increase in cooling rate. A fine AF dominant microstructure was formed under a high driving force for the transformation from austenite to ferrite at lower temperatures. A high deformation of 43–65% discouraged the formation of acicular ferrite because of the increase in austenite grain boundaries serving as nucleation sites. The fraction of high-angled grain boundaries that acted as obstacles to cleavage cracks was the highest in the sample cooled at 5 °C/s because of full AF structure formation. The hardness increased significantly as the cooling rate increased from 2 to 15 °C/s, whereas it decreased under the condition of deformation because of the formation of (quasi-)polygonal ferrite. By applying accelerated water cooling, the mechanical properties, particularly impact toughness, were significantly improved as a result of fine AF microstructure formation

Guo Yuan - One of the best experts on this subject based on the ideXlab platform.

  • Relationship Between Impact Toughness and Microstructure for the As-Rolled and Simulated HAZ of Low-Carbon Steel Containing Ti-Ca Oxide Particles
    Metallurgical and Materials Transactions A, 2020
    Co-Authors: Xin Wang, Chao Wang, Jian Kang, Guodong Wang, Devesh Misra, Guo Yuan
    Abstract:

    In this study, the microstructure and mechanical properties of Ti-Ca Deoxidized low-carbon Steel compared with Al-Ca Deoxidized Steel were investigated. Hot rolling experiment and high heat input welding heat-affected zone (HAZ) simulation were carried out. In situ transformation behavior and crack propagation during impact in simulated HAZ were analyzed. The results indicated that interlocking acicular ferrite (AF) was the dominant microstructure after Ti-Ca deoxidation treatment, and TiOx-CaO-Al2O3-MnS-type complex inclusion with maximum proportion was effective for AF nucleation. However, Al2O3-CaO-(Ca, Mn)S-type inclusion that was dominant in Al-Ca Steel exhibited significantly lower ability for AF nucleation. The high ratio of high-angle grain boundaries/low-angle grain boundaries in AF microstructure hindered the initiation and propagation of crack. The stress concentration in the vicinity of crack tip can be released because of superior deformability of AF structure as compared to bainite packets. By introducing Ti-Ca oxide particles, the mechanical properties of hot-rolled Steel plate and HAZ, particularly impact toughness, were significantly enhanced because of the formation of fine AF.

  • An in-situ microscopy study on nucleation and growth of acicular ferrite in Ti-Ca-Zr Deoxidized low-carbon Steel
    Materials Characterization, 2020
    Co-Authors: Xin Wang, Chao Wang, Jian Kang, Guo Yuan, R.d.k. Misra, Guodong Wang
    Abstract:

    Abstract We describe here an in-situ microscopy study on the nucleation and growth of acicular ferrite in Ti-Ca-Zr Deoxidized low-carbon Steel as a function of cooling rate. The study indicated the starting transformation temperature of acicular ferrite decreased with increasing cooling rate. Moreover, the average growth rate of acicular ferrite was increased from ~2.2 μm/s to ~14.4 μm/s with the increase of cooling rate from 2 °C/s to 15 °C/s. In Ti-Ca-Zr Deoxidized Steel, (Ti, Ca, Zr, Al)-O-Mn-S oxide inclusions effectively promoted the formation of intragranular acicular ferrite. A significantly high proportion of acicular ferrite was characterized by high angle grain boundaries and reduced grain size. When the cooling rate was low at 5 °C/s, the proportion of acicular ferrite was high at ~85%, with ~48% high angle grain boundaries and small average grain size of ~2.7 μm. Additionally, MnS precipitated in the vicinity of (Ti, Ca, Zr, Al)-O-Mn-S oxide particles, which promoted the nucleation of acicular ferrite.

  • Microstructure and mechanical properties of hot-rolled low-carbon Steel containing Ti–Ca oxide particles: a comparison between base metal and HAZ
    Journal of Iron and Steel Research International, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    The effect of inclusion-induced nucleation on hot-rolled Steel base metal was evaluated in comparison with welding heat-affected zone (HAZ). Microstructure and mechanical properties of hot-rolled low-carbon Steel containing Ti–Ca oxide particles were studied. The results showed that inclusions in Ti–Ca Deoxidized Steel distributed dispersely and were effective for intragranular acicular ferrite nucleation. Under hot rolling and controlled cooling conditions, microstructure in Steel base metal was significantly refined and mainly consisted of acicular ferrite and intragranular bainite, which exhibited higher strength and excellent toughness. The microstructural evolution behavior followed the process that acicular ferrite plates divided the austenite grain, intragranular bainite packets formed between interlocking acicular ferrite plates, and the remaining austenite decomposed into fine polygonal ferrite grains. The resultant complex microstructure improved the impact toughness significantly. By comparison, in HAZ microstructure, laminar grain boundary ferrite having similar crystallography orientation showed adverse effect on toughness.

  • Effect of Thermomechanical Treatment on Acicular Ferrite Formation in Ti–Ca Deoxidized Low Carbon Steel
    Metals, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    Transformation behaviors and mechanical properties under thermomechanical treatment conditions of Ti–Ca Deoxidized low carbon Steel were studied in comparison to Al–Ca treated Steel. A thermomechanical simulation and a hot rolling experiment were carried out. Inclusions and microstructures were characterized, and the transformation mechanism was analyzed. The results indicated that typical inclusions in Ti–Ca Deoxidized Steel were TiOx-MnS-Al2O3-CaO, TiOx-MnO-Al2O3-CaO, and TiOx-MnS, which were effective for acicular ferrite (AF) nucleation. Acicular ferrite formation temperature decreased with an increase in cooling rate. A fine AF dominant microstructure was formed under a high driving force for the transformation from austenite to ferrite at lower temperatures. A high deformation of 43–65% discouraged the formation of acicular ferrite because of the increase in austenite grain boundaries serving as nucleation sites. The fraction of high-angled grain boundaries that acted as obstacles to cleavage cracks was the highest in the sample cooled at 5 °C/s because of full AF structure formation. The hardness increased significantly as the cooling rate increased from 2 to 15 °C/s, whereas it decreased under the condition of deformation because of the formation of (quasi-)polygonal ferrite. By applying accelerated water cooling, the mechanical properties, particularly impact toughness, were significantly improved as a result of fine AF microstructure formation.

  • Effect of Thermomechanical Treatment on Acicular Ferrite Formation in Ti–Ca Deoxidized Low Carbon Steel
    MDPI AG, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    Transformation behaviors and mechanical properties under thermomechanical treatment conditions of Ti–Ca Deoxidized low carbon Steel were studied in comparison to Al–Ca treated Steel. A thermomechanical simulation and a hot rolling experiment were carried out. Inclusions and microstructures were characterized, and the transformation mechanism was analyzed. The results indicated that typical inclusions in Ti–Ca Deoxidized Steel were TiOx-MnS-Al2O3-CaO, TiOx-MnO-Al2O3-CaO, and TiOx-MnS, which were effective for acicular ferrite (AF) nucleation. Acicular ferrite formation temperature decreased with an increase in cooling rate. A fine AF dominant microstructure was formed under a high driving force for the transformation from austenite to ferrite at lower temperatures. A high deformation of 43–65% discouraged the formation of acicular ferrite because of the increase in austenite grain boundaries serving as nucleation sites. The fraction of high-angled grain boundaries that acted as obstacles to cleavage cracks was the highest in the sample cooled at 5 °C/s because of full AF structure formation. The hardness increased significantly as the cooling rate increased from 2 to 15 °C/s, whereas it decreased under the condition of deformation because of the formation of (quasi-)polygonal ferrite. By applying accelerated water cooling, the mechanical properties, particularly impact toughness, were significantly improved as a result of fine AF microstructure formation

Xin Wang - One of the best experts on this subject based on the ideXlab platform.

  • Relationship Between Impact Toughness and Microstructure for the As-Rolled and Simulated HAZ of Low-Carbon Steel Containing Ti-Ca Oxide Particles
    Metallurgical and Materials Transactions A, 2020
    Co-Authors: Xin Wang, Chao Wang, Jian Kang, Guodong Wang, Devesh Misra, Guo Yuan
    Abstract:

    In this study, the microstructure and mechanical properties of Ti-Ca Deoxidized low-carbon Steel compared with Al-Ca Deoxidized Steel were investigated. Hot rolling experiment and high heat input welding heat-affected zone (HAZ) simulation were carried out. In situ transformation behavior and crack propagation during impact in simulated HAZ were analyzed. The results indicated that interlocking acicular ferrite (AF) was the dominant microstructure after Ti-Ca deoxidation treatment, and TiOx-CaO-Al2O3-MnS-type complex inclusion with maximum proportion was effective for AF nucleation. However, Al2O3-CaO-(Ca, Mn)S-type inclusion that was dominant in Al-Ca Steel exhibited significantly lower ability for AF nucleation. The high ratio of high-angle grain boundaries/low-angle grain boundaries in AF microstructure hindered the initiation and propagation of crack. The stress concentration in the vicinity of crack tip can be released because of superior deformability of AF structure as compared to bainite packets. By introducing Ti-Ca oxide particles, the mechanical properties of hot-rolled Steel plate and HAZ, particularly impact toughness, were significantly enhanced because of the formation of fine AF.

  • An in-situ microscopy study on nucleation and growth of acicular ferrite in Ti-Ca-Zr Deoxidized low-carbon Steel
    Materials Characterization, 2020
    Co-Authors: Xin Wang, Chao Wang, Jian Kang, Guo Yuan, R.d.k. Misra, Guodong Wang
    Abstract:

    Abstract We describe here an in-situ microscopy study on the nucleation and growth of acicular ferrite in Ti-Ca-Zr Deoxidized low-carbon Steel as a function of cooling rate. The study indicated the starting transformation temperature of acicular ferrite decreased with increasing cooling rate. Moreover, the average growth rate of acicular ferrite was increased from ~2.2 μm/s to ~14.4 μm/s with the increase of cooling rate from 2 °C/s to 15 °C/s. In Ti-Ca-Zr Deoxidized Steel, (Ti, Ca, Zr, Al)-O-Mn-S oxide inclusions effectively promoted the formation of intragranular acicular ferrite. A significantly high proportion of acicular ferrite was characterized by high angle grain boundaries and reduced grain size. When the cooling rate was low at 5 °C/s, the proportion of acicular ferrite was high at ~85%, with ~48% high angle grain boundaries and small average grain size of ~2.7 μm. Additionally, MnS precipitated in the vicinity of (Ti, Ca, Zr, Al)-O-Mn-S oxide particles, which promoted the nucleation of acicular ferrite.

  • Microstructure and mechanical properties of hot-rolled low-carbon Steel containing Ti–Ca oxide particles: a comparison between base metal and HAZ
    Journal of Iron and Steel Research International, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    The effect of inclusion-induced nucleation on hot-rolled Steel base metal was evaluated in comparison with welding heat-affected zone (HAZ). Microstructure and mechanical properties of hot-rolled low-carbon Steel containing Ti–Ca oxide particles were studied. The results showed that inclusions in Ti–Ca Deoxidized Steel distributed dispersely and were effective for intragranular acicular ferrite nucleation. Under hot rolling and controlled cooling conditions, microstructure in Steel base metal was significantly refined and mainly consisted of acicular ferrite and intragranular bainite, which exhibited higher strength and excellent toughness. The microstructural evolution behavior followed the process that acicular ferrite plates divided the austenite grain, intragranular bainite packets formed between interlocking acicular ferrite plates, and the remaining austenite decomposed into fine polygonal ferrite grains. The resultant complex microstructure improved the impact toughness significantly. By comparison, in HAZ microstructure, laminar grain boundary ferrite having similar crystallography orientation showed adverse effect on toughness.

  • Effect of Thermomechanical Treatment on Acicular Ferrite Formation in Ti–Ca Deoxidized Low Carbon Steel
    Metals, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    Transformation behaviors and mechanical properties under thermomechanical treatment conditions of Ti–Ca Deoxidized low carbon Steel were studied in comparison to Al–Ca treated Steel. A thermomechanical simulation and a hot rolling experiment were carried out. Inclusions and microstructures were characterized, and the transformation mechanism was analyzed. The results indicated that typical inclusions in Ti–Ca Deoxidized Steel were TiOx-MnS-Al2O3-CaO, TiOx-MnO-Al2O3-CaO, and TiOx-MnS, which were effective for acicular ferrite (AF) nucleation. Acicular ferrite formation temperature decreased with an increase in cooling rate. A fine AF dominant microstructure was formed under a high driving force for the transformation from austenite to ferrite at lower temperatures. A high deformation of 43–65% discouraged the formation of acicular ferrite because of the increase in austenite grain boundaries serving as nucleation sites. The fraction of high-angled grain boundaries that acted as obstacles to cleavage cracks was the highest in the sample cooled at 5 °C/s because of full AF structure formation. The hardness increased significantly as the cooling rate increased from 2 to 15 °C/s, whereas it decreased under the condition of deformation because of the formation of (quasi-)polygonal ferrite. By applying accelerated water cooling, the mechanical properties, particularly impact toughness, were significantly improved as a result of fine AF microstructure formation.

  • Effect of Thermomechanical Treatment on Acicular Ferrite Formation in Ti–Ca Deoxidized Low Carbon Steel
    MDPI AG, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    Transformation behaviors and mechanical properties under thermomechanical treatment conditions of Ti–Ca Deoxidized low carbon Steel were studied in comparison to Al–Ca treated Steel. A thermomechanical simulation and a hot rolling experiment were carried out. Inclusions and microstructures were characterized, and the transformation mechanism was analyzed. The results indicated that typical inclusions in Ti–Ca Deoxidized Steel were TiOx-MnS-Al2O3-CaO, TiOx-MnO-Al2O3-CaO, and TiOx-MnS, which were effective for acicular ferrite (AF) nucleation. Acicular ferrite formation temperature decreased with an increase in cooling rate. A fine AF dominant microstructure was formed under a high driving force for the transformation from austenite to ferrite at lower temperatures. A high deformation of 43–65% discouraged the formation of acicular ferrite because of the increase in austenite grain boundaries serving as nucleation sites. The fraction of high-angled grain boundaries that acted as obstacles to cleavage cracks was the highest in the sample cooled at 5 °C/s because of full AF structure formation. The hardness increased significantly as the cooling rate increased from 2 to 15 °C/s, whereas it decreased under the condition of deformation because of the formation of (quasi-)polygonal ferrite. By applying accelerated water cooling, the mechanical properties, particularly impact toughness, were significantly improved as a result of fine AF microstructure formation

Jian Kang - One of the best experts on this subject based on the ideXlab platform.

  • Relationship Between Impact Toughness and Microstructure for the As-Rolled and Simulated HAZ of Low-Carbon Steel Containing Ti-Ca Oxide Particles
    Metallurgical and Materials Transactions A, 2020
    Co-Authors: Xin Wang, Chao Wang, Jian Kang, Guodong Wang, Devesh Misra, Guo Yuan
    Abstract:

    In this study, the microstructure and mechanical properties of Ti-Ca Deoxidized low-carbon Steel compared with Al-Ca Deoxidized Steel were investigated. Hot rolling experiment and high heat input welding heat-affected zone (HAZ) simulation were carried out. In situ transformation behavior and crack propagation during impact in simulated HAZ were analyzed. The results indicated that interlocking acicular ferrite (AF) was the dominant microstructure after Ti-Ca deoxidation treatment, and TiOx-CaO-Al2O3-MnS-type complex inclusion with maximum proportion was effective for AF nucleation. However, Al2O3-CaO-(Ca, Mn)S-type inclusion that was dominant in Al-Ca Steel exhibited significantly lower ability for AF nucleation. The high ratio of high-angle grain boundaries/low-angle grain boundaries in AF microstructure hindered the initiation and propagation of crack. The stress concentration in the vicinity of crack tip can be released because of superior deformability of AF structure as compared to bainite packets. By introducing Ti-Ca oxide particles, the mechanical properties of hot-rolled Steel plate and HAZ, particularly impact toughness, were significantly enhanced because of the formation of fine AF.

  • An in-situ microscopy study on nucleation and growth of acicular ferrite in Ti-Ca-Zr Deoxidized low-carbon Steel
    Materials Characterization, 2020
    Co-Authors: Xin Wang, Chao Wang, Jian Kang, Guo Yuan, R.d.k. Misra, Guodong Wang
    Abstract:

    Abstract We describe here an in-situ microscopy study on the nucleation and growth of acicular ferrite in Ti-Ca-Zr Deoxidized low-carbon Steel as a function of cooling rate. The study indicated the starting transformation temperature of acicular ferrite decreased with increasing cooling rate. Moreover, the average growth rate of acicular ferrite was increased from ~2.2 μm/s to ~14.4 μm/s with the increase of cooling rate from 2 °C/s to 15 °C/s. In Ti-Ca-Zr Deoxidized Steel, (Ti, Ca, Zr, Al)-O-Mn-S oxide inclusions effectively promoted the formation of intragranular acicular ferrite. A significantly high proportion of acicular ferrite was characterized by high angle grain boundaries and reduced grain size. When the cooling rate was low at 5 °C/s, the proportion of acicular ferrite was high at ~85%, with ~48% high angle grain boundaries and small average grain size of ~2.7 μm. Additionally, MnS precipitated in the vicinity of (Ti, Ca, Zr, Al)-O-Mn-S oxide particles, which promoted the nucleation of acicular ferrite.

  • Microstructure and mechanical properties of hot-rolled low-carbon Steel containing Ti–Ca oxide particles: a comparison between base metal and HAZ
    Journal of Iron and Steel Research International, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    The effect of inclusion-induced nucleation on hot-rolled Steel base metal was evaluated in comparison with welding heat-affected zone (HAZ). Microstructure and mechanical properties of hot-rolled low-carbon Steel containing Ti–Ca oxide particles were studied. The results showed that inclusions in Ti–Ca Deoxidized Steel distributed dispersely and were effective for intragranular acicular ferrite nucleation. Under hot rolling and controlled cooling conditions, microstructure in Steel base metal was significantly refined and mainly consisted of acicular ferrite and intragranular bainite, which exhibited higher strength and excellent toughness. The microstructural evolution behavior followed the process that acicular ferrite plates divided the austenite grain, intragranular bainite packets formed between interlocking acicular ferrite plates, and the remaining austenite decomposed into fine polygonal ferrite grains. The resultant complex microstructure improved the impact toughness significantly. By comparison, in HAZ microstructure, laminar grain boundary ferrite having similar crystallography orientation showed adverse effect on toughness.

  • Effect of Thermomechanical Treatment on Acicular Ferrite Formation in Ti–Ca Deoxidized Low Carbon Steel
    Metals, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    Transformation behaviors and mechanical properties under thermomechanical treatment conditions of Ti–Ca Deoxidized low carbon Steel were studied in comparison to Al–Ca treated Steel. A thermomechanical simulation and a hot rolling experiment were carried out. Inclusions and microstructures were characterized, and the transformation mechanism was analyzed. The results indicated that typical inclusions in Ti–Ca Deoxidized Steel were TiOx-MnS-Al2O3-CaO, TiOx-MnO-Al2O3-CaO, and TiOx-MnS, which were effective for acicular ferrite (AF) nucleation. Acicular ferrite formation temperature decreased with an increase in cooling rate. A fine AF dominant microstructure was formed under a high driving force for the transformation from austenite to ferrite at lower temperatures. A high deformation of 43–65% discouraged the formation of acicular ferrite because of the increase in austenite grain boundaries serving as nucleation sites. The fraction of high-angled grain boundaries that acted as obstacles to cleavage cracks was the highest in the sample cooled at 5 °C/s because of full AF structure formation. The hardness increased significantly as the cooling rate increased from 2 to 15 °C/s, whereas it decreased under the condition of deformation because of the formation of (quasi-)polygonal ferrite. By applying accelerated water cooling, the mechanical properties, particularly impact toughness, were significantly improved as a result of fine AF microstructure formation.

  • Effect of Thermomechanical Treatment on Acicular Ferrite Formation in Ti–Ca Deoxidized Low Carbon Steel
    MDPI AG, 2019
    Co-Authors: Chao Wang, Xin Wang, Jian Kang, Guo Yuan, Guodong Wang
    Abstract:

    Transformation behaviors and mechanical properties under thermomechanical treatment conditions of Ti–Ca Deoxidized low carbon Steel were studied in comparison to Al–Ca treated Steel. A thermomechanical simulation and a hot rolling experiment were carried out. Inclusions and microstructures were characterized, and the transformation mechanism was analyzed. The results indicated that typical inclusions in Ti–Ca Deoxidized Steel were TiOx-MnS-Al2O3-CaO, TiOx-MnO-Al2O3-CaO, and TiOx-MnS, which were effective for acicular ferrite (AF) nucleation. Acicular ferrite formation temperature decreased with an increase in cooling rate. A fine AF dominant microstructure was formed under a high driving force for the transformation from austenite to ferrite at lower temperatures. A high deformation of 43–65% discouraged the formation of acicular ferrite because of the increase in austenite grain boundaries serving as nucleation sites. The fraction of high-angled grain boundaries that acted as obstacles to cleavage cracks was the highest in the sample cooled at 5 °C/s because of full AF structure formation. The hardness increased significantly as the cooling rate increased from 2 to 15 °C/s, whereas it decreased under the condition of deformation because of the formation of (quasi-)polygonal ferrite. By applying accelerated water cooling, the mechanical properties, particularly impact toughness, were significantly improved as a result of fine AF microstructure formation