The Experts below are selected from a list of 2370 Experts worldwide ranked by ideXlab platform
Guodong Wang - One of the best experts on this subject based on the ideXlab platform.
-
Effect of annealing after Strip Casting on microstructure, precipitates and texture in non-oriented silicon steel produced by twin-roll Strip Casting
Materials Characterization, 2018Co-Authors: Lan Mengfei, Cao Guangming, Yang Wang, Zhang Yuanxiang, Feng Fang, Guo Yuan, R.d.k. Misra, Guodong WangAbstract:Abstract A 3.1 mm thick non-oriented Fe-1.0% Si steel as-Cast Strip was produced by twin-roll Strip Casting. Samples with/without Strip annealing were cold rolled to 0.5 mm and then annealed. The development of microstructure, precipitate and texture was characterized along the entire processing route. It was found that annealing after Strip Casting had a minor influence on the average grain size and texture of the as-Cast Strip. A large number of particles precipitated and coarsened during the Strip annealing process. Meanwhile, precipitates hindered dislocation slip and crystal rotation such that more significant in-grain shear bands were formed in cold rolled sheets. During recrystallization annealing process, the newly formed fine precipitates in directly cold-rolled sheets consumed stored strain energy and also hindered grain growth. But the initial precipitates in the annealed Strip grew further and the effect of pinning of dislocations and grain boundary was lost. Therefore, annealed sheets with Strip annealing process showed homogeneous equiaxed grains and the recrystallization texture was characterized by strong λ-fiber texture, which led to high permeability.
-
formation of widmanstatten austenite in Strip Cast grain oriented silicon steel
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2017Co-Authors: Hong-yu Song, Guodong Wang, Hai-tao Liu, J J JonasAbstract:The formation of Widmanstatten austenite was studied in Strip Cast grain-oriented silicon steel. The microstructure was investigated by optical microscopy and scanning electron microscopy. The orientations of the ferrite, Widmanstatten austenite, and martensite were determined using electron backscatter diffraction. The Widmanstatten austenite exhibits a lath-like shape and nucleates directly on the ferrite grain boundaries. This differs significantly from earlier work on duplex stainless steels. The orientation relationship between the Widmanstatten austenite and the parent ferrite is closer to Kurdjumov–Sachs than to Nishiyama–Wassermann. The ferrite boundaries migrate so as to accommodate the habit planes of the laths, leading to the presence of zigzag boundaries in the as-Cast Strip. Carbon partitioning into the Widmanstatten austenite and silicon partitioning into the parent ferrite were observed.
-
Effect of cerium on the as-Cast microstructure and tensile ductility of the twin-roll Casting Fe–6.5 wt% Si alloy
Materials Letters, 2016Co-Authors: Hai-tao Liu, Zhenyu Liu, Cao Guangming, Wang Xianglong, Li Chenggang, Guodong WangAbstract:Abstract Fe–6.5 wt% Si alloy doped with cerium is fabricated by twin-roll Casting. Ce 2 O 2 S precipitates in the melt and acts as the efficient nucleation agent, leading to a refined solidification microstructure. The tensile ductility of this as-Cast Strip significantly reaches up to 56.8% at 600 °C, which is superior to the 22.8% of the as-Cast Strip undoped with cerium. The much more uniform and finer solidification microstructure along with the strengthened grain boundary is inferred to result in the dramatic improvement in tensile ductility.
-
Effects of initial microstructure and texture on microstructure, texture evolution and magnetic properties of non-oriented electrical steel
Journal of Magnetism and Magnetic Materials, 2016Co-Authors: Hai-tao Liu, Zhenyu Liu, Hui Wang, Yi Liu, Fei Gao, An Lingzi, Zhao Shiqi, Guodong WangAbstract:Abstract An equiaxed grained as-Cast Strip and a columnar grained as-Cast Strip was produced by using twin-roll Strip Casting, respectively. Both as-Cast Strips mainly containing 0.71 wt%Si and 0.44 wt%Al were cold rolled and annealed with or without the hot rolling prior to cold rolling. Microstructure, texture evolution along the whole processing routes and the magnetic properties were investigated in detail. It was found that the equiaxed grained Strip was characterized by almost random texture while the columnar grained Strip was dominated by strong λ-fiber ( ‖ND) texture. After cold rolling and annealing, all the final sheets of both the as-Cast Strips showed extremely weak γ-fiber ( ‖ND) recrystallization texture. In addition, the finally annealed sheets of the equiaxed grained Strip were dominated by relatively weak λ-fiber and strong Goss ({110} ) recrystallization texture while those of the columnar grained Strip were dominated by much stronger λ-fiber and much weaker Goss recrystallization texture regardless of whether the hot rolling was adopted before cold rolling, thus the former showed much lower magnetic induction than the latter. On the other hand, even though the finally annealed sheets of the equiaxed grained Strip showed a little more homogeneous recrystallization microstructure with a little bigger grain size than those of the columnar grained Strip in the case of no hot rolling, a much higher iron loss was displayed. By contrast, in the case of hot rolling, the former exhibited a little lower iron loss than the latter as a result of the more significant increase in grain size and λ-fiber recrystallization texture. The introduction of the hot rolling could increase the grain size, strengthen λ-fiber texture and weaken Goss texture of the finally annealed sheets of both the as-Cast Strips, leading to a much improvement in both the magnetic induction and iron loss.
-
microstructure texture evolution and magnetic properties of Strip Casting non oriented 6 5 wt si electrical steel doped with cerium
Materials Characterization, 2015Co-Authors: Haoze Li, Guodong WangAbstract:Abstract A 0.3 mm thick non-oriented 6.5 wt.% Si electrical steel sheet doped with cerium is produced by twin-roll Strip Casting, hot rolling, warm rolling and annealing. A detailed study of the cerium precipitates in the as-Cast Strip, microstructure and texture evolution at different processing stages is carried out by electron probe micro-analysis, optical microscopy, X-ray diffraction and electron backscattered diffraction analysis. Grain interior distributing precipitates identified as Ce-oxides, Ce-oxysulfides and Ce-phosphides, and boundary distributing Ce-oxides and Ce-phosphides are observed in the as-Cast Strip. The initial as-Cast Strip is characterized by a much finer solidification microstructure and dominated by obvious //ND texture through the Strip thickness. After hot and warm rolling, inhomogeneous microstructure containing large amounts of in-grain shear bands is characterized by mixed //RD and //ND textures. The texture of the annealed sheet with a relatively large average grain size is far more optimized by the domination of the beneficial cube, rotated cube, {001} to {001} and Goss texture components, and the elimination of the detrimental γ-fiber texture, leading to a superior magnetic induction and improved iron loss.
Shinji Kumai - One of the best experts on this subject based on the ideXlab platform.
-
Strip Casting of Recycled Aluminum Alloys by a Twin Roll Caster
Waste and Biomass Valorization, 2012Co-Authors: Toshio Haga, Shinji Kumai, Hisaki WatariAbstract:Purpose The purpose of the present study is to investigate the mechanical properties of roll Cast recycled 6016 aluminum alloy Strip using a vertical type high-speed twin roll Caster. Method A vertical type twin roll Caster with 1500 mm diameter rolls was designed and assembled to Cast aluminum alloy Strip at a high speed and high cooling rate. 6016 aluminum alloy sheet is typically used for the bodies of automobiles. Virgin 6016 (0.16 %Fe) and Fe added 6016 (0.45 %Fe) (henceforth called recycled 6016) alloys were Cast at a speed of 60 m/min. The microstructure of the as-Cast Strip was observed. The as-Cast Strip could be cold rolled, without homogenization, down to 1 mm. Tension test and 180-degree bending test were conducted to investigate the properties of recycled 6016. Results The Strip could be Cast at a speed of 60 m/min. The thickness of the as-Cast Strip was 3.4 mm, and the microstructure was very fine. The as-Cast Strip could be cold rolled, without homogenization, down to 1 mm. T4 heat-treated Strips of virgin 6016 (0.16 %Fe) and recycled 6016 (0.45 %Fe) alloys could be bent at 180 degrees without breaking. The Fe content had no effect on the results of the tension test and 180-degree bending test. Conclusions The mechanical properties of recycled 6016 Strip were improved by rapid solidification of the twin roll Caster. The twin roll Caster decreased the effect of Fe.
-
Investigation of the Influence of the Roll Surface on the Cast Strip at the Casting Using a Vertical Type High Speed Twin Roll Caster
Applied Mechanics and Materials, 2012Co-Authors: Takuya Yamashiki, Toshio Haga, Shinji Kumai, Hisaki WatariAbstract:A vertical type high speed twin roll Caster can be Cast an aluminum alloy Strip directly from a melt at high Casting speed. However defects of the Cast Strip occurred at faster roll speed, which includes small cracks on the Cast Strip and unsoundness thickness distribution. They are related to contact condition of roll surface and melt. In the present study, a grooved roll was used to eliminate the defects and adopted in terms of the cost saving. We experimented using several grooved rolls with different patterns. When the groove width was 0.45mm; depth 0.2mm; pitch 0.1mm and 1.0mm, stable Casting was possible. The shape of bulge was formed on the Cast Strip surface by the grooved roll. As a result of color check, we found that the grooved roll eliminate the small cracks. We stopped the rotated roll during the Casting to observe the contact condition between the melt and the roll, and confirmed how the bulge was formed. The as-Cast Strip with the bulge was able to cold rolling.
-
Strip Casting of Al-25%Si Alloy
Advanced Materials Research, 2012Co-Authors: Toshio Haga, Shinji Kumai, Hideto Harada, Hisaki WatariAbstract:Strip Casting of Al-25%Si Strip was tried using an unequal diameter twin roll Caster. The diameter of the lower roll (large roll) was 1000mm and the diameter of the upper roll (small roll) was 250mm. Roll material was mild steel. The sound Strip could be Cast at the speeds ranging from 8 m/min to 12 m/min. The Strip did not stick to the roll without the parting material. The primary Si, which existed at centre area of the thickness direction, was larger than that which existed at other area. The size of the primary Si was smaller than 0.2 mm. Eutectic Si was smaller 5μm. The as-Cast Strip was ranging from 2mm to 3mm thick and its width was 100mm. The as-Cast Strip could be hot rolled down to 1mm. The hot rolled Strip was cold rolled. The primary Si became smaller and the pore occurred around the primary Si after the rolling.
-
Strip Casting of 6061 and recycled 6061 alloy by an unequal diameter twin roll Caster
Advanced Materials Research, 2011Co-Authors: Toshio Haga, Shinji Kumai, Ryoji Nakamura, Hideki Inui, Hisaki WatariAbstract:A 6061 aluminium alloy and an alloy with increased Fe content, representing recycled 6061 aluminium alloy were Cast into Strips at speed of 30m/min by an unequal diameter twin roll Caster. The Fe content of 6061 aluminium alloy and the model of recycled 6061 aluminium alloy was 0.36 mass% and 0.59 mass%, respectively. Ripple marks, which are typical surface defect of roll Cast Strips, did not occur on the surface of both as-Cast Strips. Fe content did not influence the surface condition of the roll-Cast-Strip. The as-Cast Strip was cold rolled down to 1 mm, T4 heat treatment was conducted, and then subjected to180 degrees bending test. The result of 180 degrees bending test shows that roll Cast 6061 aluminium alloy and 6061 aluminium alloy with increased Fe as recycled had bending ability as same as that of roll-Cast 6022 aluminium alloy. In the Strip Cast by the twin roll Caster of the present study, increased Fe content did not influence on the result of the180 degrees bending test.
-
Roll Casting of Al-SiCp Composite Strip
Advanced Materials Research, 2010Co-Authors: Ryoji Nakamura, Hideto Harada, Shinji Kumai, Teppei Nakamura, Hisaki WatariAbstract:Roll Casting of Al-SiCp composite alloy Strip was tried using a vertical type high speed twin roll Caster equipped with mild steel rolls. The Al-20vol% SiCp and Al-30vol%SiCp alloy could be roll-Cast to the Strip. The Casting speed was 30m/min. The thickness of as-Cast Strip was thinner than 2.5mm. The SiCp powder was dispersed uniformly at the thickness direction. The as-Cast Strip could be thin down to 1mm by the hot rolling and the cold rolling without broken.
Toshio Haga - One of the best experts on this subject based on the ideXlab platform.
-
Hot forging of roll-Cast high aluminum content magnesium alloys
2017Co-Authors: Tomohiro Kishi, Hisaki Watari, Mayumi Suzuki, Toshio HagaAbstract:This paper reports on hot forging of high aluminum content magnesium alloy sheets manufactured using horizontal twin-roll Casting. AZ111 and AZ131 were applied for twin-roll Casting, and a hot-forging test was performed to manufacture high-strength magnesium alloy components economically. For twin-roll Casting, the Casting conditions of a thick sheet for hot forging were investigated. It was found that twin-roll Casting of a 10mm-thick magnesium alloy sheet was possible at a roll speed of 2.5m/min. The grain size of the Cast Strip was 50 to 70µm. In the hot-forging test, blank material was obtained from as-Cast Strip. A servo press machine with a servo die cushion was used to investigate appropriate forging conditions (e.g., temperature, forging load, and back pressure) for twin-roll Casts (TRCs) AZ111 and AZ131. It was determined that high aluminum content magnesium alloy sheets manufactured using twin-roll Casting could be forged with a forging load of 150t and a back pressure of 3t at 420 to 430°C. Applying back pressure during hot forging effectively forged a pin-shaped product.This paper reports on hot forging of high aluminum content magnesium alloy sheets manufactured using horizontal twin-roll Casting. AZ111 and AZ131 were applied for twin-roll Casting, and a hot-forging test was performed to manufacture high-strength magnesium alloy components economically. For twin-roll Casting, the Casting conditions of a thick sheet for hot forging were investigated. It was found that twin-roll Casting of a 10mm-thick magnesium alloy sheet was possible at a roll speed of 2.5m/min. The grain size of the Cast Strip was 50 to 70µm. In the hot-forging test, blank material was obtained from as-Cast Strip. A servo press machine with a servo die cushion was used to investigate appropriate forging conditions (e.g., temperature, forging load, and back pressure) for twin-roll Casts (TRCs) AZ111 and AZ131. It was determined that high aluminum content magnesium alloy sheets manufactured using twin-roll Casting could be forged with a forging load of 150t and a back pressure of 3t at 420 to 430°C. App...
-
PRICM: 8 Pacific Rim International Congress on Advanced Materials and Processing - Solidification Heat Transfer Analysis of AZ91D Cast Strip by Using a Horizontal Twin Roll Caster
Proceedings of the 8th Pacific Rim International Congress on Advanced Materials and Processing, 2013Co-Authors: Hideto Harada, Hisaki Watari, Shinichi Nishida, Takayuki Nagumo, Masaki Endo, Toshio HagaAbstract:This study was investigated about Solidification heat transfer analysis of AZ91D Cast Strip by using a horizontal twin roll Caster. Density of magnesium alloy is the lightest within all of the practicable metal, and AZ91D magnesium alloy have high specific strength. So, magnesium alloy was expected to apply for transport machines. Twin roll Caster is able to Cast low cost magnesium Strip. The heat transfer coefficient between the molten magnesium alloy and copper roll is important to Cast magnesium Strip. The present study investigated the heat transfer coefficient and distribution of temperature during Casting by the two dimensional heat transfer solidification analysis. We investigated about the effect of heat transfer coefficient between roll velocity and roll gap. AZ91D Cast by twin roll Caster at 16 m/min. the Caster using copper roll, and roll size was φ 300 mm. roll gap was 3 mm. This experimental condition was able to Cast AZ91D Strip Cast, and this study of twin roll Caster of optimum K value was 36.5.
-
Strip Casting of Recycled Aluminum Alloys by a Twin Roll Caster
Waste and Biomass Valorization, 2012Co-Authors: Toshio Haga, Shinji Kumai, Hisaki WatariAbstract:Purpose The purpose of the present study is to investigate the mechanical properties of roll Cast recycled 6016 aluminum alloy Strip using a vertical type high-speed twin roll Caster. Method A vertical type twin roll Caster with 1500 mm diameter rolls was designed and assembled to Cast aluminum alloy Strip at a high speed and high cooling rate. 6016 aluminum alloy sheet is typically used for the bodies of automobiles. Virgin 6016 (0.16 %Fe) and Fe added 6016 (0.45 %Fe) (henceforth called recycled 6016) alloys were Cast at a speed of 60 m/min. The microstructure of the as-Cast Strip was observed. The as-Cast Strip could be cold rolled, without homogenization, down to 1 mm. Tension test and 180-degree bending test were conducted to investigate the properties of recycled 6016. Results The Strip could be Cast at a speed of 60 m/min. The thickness of the as-Cast Strip was 3.4 mm, and the microstructure was very fine. The as-Cast Strip could be cold rolled, without homogenization, down to 1 mm. T4 heat-treated Strips of virgin 6016 (0.16 %Fe) and recycled 6016 (0.45 %Fe) alloys could be bent at 180 degrees without breaking. The Fe content had no effect on the results of the tension test and 180-degree bending test. Conclusions The mechanical properties of recycled 6016 Strip were improved by rapid solidification of the twin roll Caster. The twin roll Caster decreased the effect of Fe.
-
Investigation of the Influence of the Roll Surface on the Cast Strip at the Casting Using a Vertical Type High Speed Twin Roll Caster
Applied Mechanics and Materials, 2012Co-Authors: Takuya Yamashiki, Toshio Haga, Shinji Kumai, Hisaki WatariAbstract:A vertical type high speed twin roll Caster can be Cast an aluminum alloy Strip directly from a melt at high Casting speed. However defects of the Cast Strip occurred at faster roll speed, which includes small cracks on the Cast Strip and unsoundness thickness distribution. They are related to contact condition of roll surface and melt. In the present study, a grooved roll was used to eliminate the defects and adopted in terms of the cost saving. We experimented using several grooved rolls with different patterns. When the groove width was 0.45mm; depth 0.2mm; pitch 0.1mm and 1.0mm, stable Casting was possible. The shape of bulge was formed on the Cast Strip surface by the grooved roll. As a result of color check, we found that the grooved roll eliminate the small cracks. We stopped the rotated roll during the Casting to observe the contact condition between the melt and the roll, and confirmed how the bulge was formed. The as-Cast Strip with the bulge was able to cold rolling.
-
Strip Casting of Al-25%Si Alloy
Advanced Materials Research, 2012Co-Authors: Toshio Haga, Shinji Kumai, Hideto Harada, Hisaki WatariAbstract:Strip Casting of Al-25%Si Strip was tried using an unequal diameter twin roll Caster. The diameter of the lower roll (large roll) was 1000mm and the diameter of the upper roll (small roll) was 250mm. Roll material was mild steel. The sound Strip could be Cast at the speeds ranging from 8 m/min to 12 m/min. The Strip did not stick to the roll without the parting material. The primary Si, which existed at centre area of the thickness direction, was larger than that which existed at other area. The size of the primary Si was smaller than 0.2 mm. Eutectic Si was smaller 5μm. The as-Cast Strip was ranging from 2mm to 3mm thick and its width was 100mm. The as-Cast Strip could be hot rolled down to 1mm. The hot rolled Strip was cold rolled. The primary Si became smaller and the pore occurred around the primary Si after the rolling.
Chris R. Killmore - One of the best experts on this subject based on the ideXlab platform.
-
The effect of cooling rate and coiling temperature on the niobium retention in Ultra-Thin Cast Strip steel
Materials Science and Engineering: A, 2017Co-Authors: Zhizhang Wang, Kristin R Carpenter, Zhixin Chen, Chris R. KillmoreAbstract:Abstract This laboratory study utilised a dilatometer to simulate the run-out table cooling rate and the coiling temperature to investigate the effect of the cooling rate and simulated coiling conditions on the age hardening response of a niobium microalloyed Ultra-thin Cast Strip (UCS®) steel, produced by the CastRIP® Process. Three cooling rates of 1, 5 and 40 °C/s, covering very slow (1 °C/s) to typical run-out table cooling rates (40 °C/s), down to two coiling temperatures of 500 and 675 °C were used. Dilatation curves were used to determine the temperature range over which the γ-α phase transformations occurred and the final microstructures were characterized using an optical microscope equipped with an image analysis software. The subsequent age hardening response, which previous studies have shown, results from the retention of Nb in solid solution, was assessed by the hardness changes after a post heat treatment at 700 °C for 60 s. A range of age hardening responses were obtained, depending on cooling rates and cooling stop (coiling) temperatures, which indicate a different degree of Nb retention. At the same cooling rate, the lower coiling temperature of 500 °C resulted in higher Nb retention compared to the higher coiling temperature of 675 °C. As the coiling temperature of 675 °C was within the austenite to ferrite transformation range, the simulated slow cooling of the coil impacted the precipitation behaviour of Nb rendering the interpretation more complex and this will be discussed in this paper. For the 500 °C simulated coiling temperature, the higher cooling rate resulted in a higher age hardening increment thus more Nb retention.
-
Cluster strengthening of Nb-microalloyed ultra-thin Cast Strip steels produced by the CastRIP® process
Materials Science and Engineering: A, 2013Co-Authors: Sachin L. Shrestha, Chris R. Killmore, Harold R Kaul, James G. Williams, Kelvin Y. Xie, Chen Zhu, Simon P. Ringer, Kristin R Carpenter, Julie M. CairneyAbstract:Abstract This study investigated the microstructure and mechanical properties of Nb-microalloyed ultra-thin Cast Strip (UCS) steels produced by the CastRIP ® process aged at temperatures below and above the Ac 1 temperature (525–800 °C). Aging provided a rapid strength increase without loss in ductility. This is significant because, ordinarily, one of these properties would increase at the expense of the other. Atom probe tomography (APT) and transmission electron microscopy (TEM) revealed that the strengthening was associated with the formation of Nb-rich solute atom clusters and nanoscale precipitates within the microstructure, which retard the movement of dislocations during deformation. The changes in strength and hardness were compared to the microstructural evolution across a range of different aging temperatures and explained in terms of the nucleation kinetics. Cluster-finding algorithms were used to analyse atom probe data, providing quantitative information about the dispersion of these clusters and precipitates. Optimum strengthening was observed where the clusters particles had a radius of 1–2 nm and a volume fraction of 0.027±0.004%.
-
Effect of Nb Microalloying and Hot Rolling on Microstructure and Properties of Ultrathin Cast Strip Steels Produced by the CastRIP^® Process
Metallurgical and Materials Transactions A, 2011Co-Authors: Kelvin Y. Xie, Chris R. Killmore, James G. Williams, Chen Zhu, Julie M. Cairney, Lan Yao, Frank J. Barbaro, Simon P. RingerAbstract:The microstructure and corresponding tensile properties of both plain and Nb-microalloyed grades of ultrathin Cast Strip (UCS) low alloy steel produced using the CastRIP^® process were studied. Both as-Cast and hot-rolled Strip Cast steels with various levels of Nb microalloying were manufactured and investigated in this study. Hot rolling had little effect on the yield strength of Nb microalloyed UCS specimens for a given chemical composition, but resulted in a slightly finer microstructure. The effect of Nb microalloying was significant, and this is attributable to the promotion of finer, tougher austenite transformation products such as bainite and acicular ferrite at the expense of large polygonal ferrite grains. A fine dispersion of Nb solute clusters was observed in all Nb-containing steels following hot rolling, and it is suggested that this also contributes to the observed strengthening.
-
recent developments with ultrathin Cast Strip products produced by the Castrip process
Iron and Steel Technology, 2009Co-Authors: Daniel Geoffrey Edelman, Chris R. Killmore, Harold R Kaul, James G. Williams, Peter C Campbell, Kristin R Carpenter, Walter BlejdeAbstract:Recent product development has focussed on developing a range of higher strength structural grades, covering the Strip thickness range 0.9-1.5 mm, utilising Nb microalloying. A wide range of Nb levels have been successfully Strip Cast by the CastRIP ® process. Niobium was found to retard austenite grain refinement and substantially enhanced hardenability, which produced significant microstructural hardening and higher strength hot band. Niobium was retained in solid solution enabling further significant strengthening to be achieved from an age hardening heat treatment. Strength levels ranging from 400 MPa to in excess of 550 MPa, in combination with high ductility, were achieved in the age hardened and hot dip galvanised condition, utilising the annealing furnaces of a conventional hot dip galvanising line. The effect of microalloying content and processing conditions on the microstructure and final mechanical properties of Nb microalloyed UCS products produced by the CastRIP process are described.
-
Development of ultrathin Cast Strip products by the CastRIP® process
Iron and Steel Technology, 2007Co-Authors: Chris R. Killmore, Andrew Wolongong Phillips, Harold R Kaul, James G. Williams, Heather Creely, Peter C Campbell, Michael A. Schueren, Walter BlejdeAbstract:The main parameters that influence the final microstructure and resultant mechanical properties of ultrathin Cast Strip products are discussed, particularly the effects of thermomechanical processing conditions. The development of various grades is described.
Hai-tao Liu - One of the best experts on this subject based on the ideXlab platform.
-
formation of widmanstatten austenite in Strip Cast grain oriented silicon steel
Metallurgical and Materials Transactions A-physical Metallurgy and Materials Science, 2017Co-Authors: Hong-yu Song, Guodong Wang, Hai-tao Liu, J J JonasAbstract:The formation of Widmanstatten austenite was studied in Strip Cast grain-oriented silicon steel. The microstructure was investigated by optical microscopy and scanning electron microscopy. The orientations of the ferrite, Widmanstatten austenite, and martensite were determined using electron backscatter diffraction. The Widmanstatten austenite exhibits a lath-like shape and nucleates directly on the ferrite grain boundaries. This differs significantly from earlier work on duplex stainless steels. The orientation relationship between the Widmanstatten austenite and the parent ferrite is closer to Kurdjumov–Sachs than to Nishiyama–Wassermann. The ferrite boundaries migrate so as to accommodate the habit planes of the laths, leading to the presence of zigzag boundaries in the as-Cast Strip. Carbon partitioning into the Widmanstatten austenite and silicon partitioning into the parent ferrite were observed.
-
Effect of cerium on the as-Cast microstructure and tensile ductility of the twin-roll Casting Fe–6.5 wt% Si alloy
Materials Letters, 2016Co-Authors: Hai-tao Liu, Zhenyu Liu, Cao Guangming, Wang Xianglong, Li Chenggang, Guodong WangAbstract:Abstract Fe–6.5 wt% Si alloy doped with cerium is fabricated by twin-roll Casting. Ce 2 O 2 S precipitates in the melt and acts as the efficient nucleation agent, leading to a refined solidification microstructure. The tensile ductility of this as-Cast Strip significantly reaches up to 56.8% at 600 °C, which is superior to the 22.8% of the as-Cast Strip undoped with cerium. The much more uniform and finer solidification microstructure along with the strengthened grain boundary is inferred to result in the dramatic improvement in tensile ductility.
-
Effects of initial microstructure and texture on microstructure, texture evolution and magnetic properties of non-oriented electrical steel
Journal of Magnetism and Magnetic Materials, 2016Co-Authors: Hai-tao Liu, Zhenyu Liu, Hui Wang, Yi Liu, Fei Gao, An Lingzi, Zhao Shiqi, Guodong WangAbstract:Abstract An equiaxed grained as-Cast Strip and a columnar grained as-Cast Strip was produced by using twin-roll Strip Casting, respectively. Both as-Cast Strips mainly containing 0.71 wt%Si and 0.44 wt%Al were cold rolled and annealed with or without the hot rolling prior to cold rolling. Microstructure, texture evolution along the whole processing routes and the magnetic properties were investigated in detail. It was found that the equiaxed grained Strip was characterized by almost random texture while the columnar grained Strip was dominated by strong λ-fiber ( ‖ND) texture. After cold rolling and annealing, all the final sheets of both the as-Cast Strips showed extremely weak γ-fiber ( ‖ND) recrystallization texture. In addition, the finally annealed sheets of the equiaxed grained Strip were dominated by relatively weak λ-fiber and strong Goss ({110} ) recrystallization texture while those of the columnar grained Strip were dominated by much stronger λ-fiber and much weaker Goss recrystallization texture regardless of whether the hot rolling was adopted before cold rolling, thus the former showed much lower magnetic induction than the latter. On the other hand, even though the finally annealed sheets of the equiaxed grained Strip showed a little more homogeneous recrystallization microstructure with a little bigger grain size than those of the columnar grained Strip in the case of no hot rolling, a much higher iron loss was displayed. By contrast, in the case of hot rolling, the former exhibited a little lower iron loss than the latter as a result of the more significant increase in grain size and λ-fiber recrystallization texture. The introduction of the hot rolling could increase the grain size, strengthen λ-fiber texture and weaken Goss texture of the finally annealed sheets of both the as-Cast Strips, leading to a much improvement in both the magnetic induction and iron loss.
-
Microstructure, texture evolution and magnetic properties of Strip-Casting non-oriented 6.5 wt.% Si electrical steel doped with cerium
Materials Characterization, 2015Co-Authors: Hai-tao Liu, Zhenyu Liu, Guodong WangAbstract:Abstract A 0.3 mm thick non-oriented 6.5 wt.% Si electrical steel sheet doped with cerium is produced by twin-roll Strip Casting, hot rolling, warm rolling and annealing. A detailed study of the cerium precipitates in the as-Cast Strip, microstructure and texture evolution at different processing stages is carried out by electron probe micro-analysis, optical microscopy, X-ray diffraction and electron backscattered diffraction analysis. Grain interior distributing precipitates identified as Ce-oxides, Ce-oxysulfides and Ce-phosphides, and boundary distributing Ce-oxides and Ce-phosphides are observed in the as-Cast Strip. The initial as-Cast Strip is characterized by a much finer solidification microstructure and dominated by obvious //ND texture through the Strip thickness. After hot and warm rolling, inhomogeneous microstructure containing large amounts of in-grain shear bands is characterized by mixed //RD and //ND textures. The texture of the annealed sheet with a relatively large average grain size is far more optimized by the domination of the beneficial cube, rotated cube, {001} to {001} and Goss texture components, and the elimination of the detrimental γ-fiber texture, leading to a superior magnetic induction and improved iron loss.
-
microstructure and texture of Strip Cast grain oriented silicon steel after symmetrical and asymmetrical hot rolling
Steel Research International, 2014Co-Authors: Hong-yu Song, Hai-tao Liu, Dian-qiao Geng, Zhenyu Liu, Devesh R K Misra, Guodong WangAbstract:A grain-oriented silicon steel as-Cast Strip was produced by twin-roll Strip Casting. Then the as-Cast Strip was symmetrically and asymmetrically hot rolled, respectively. The microstructure and texture evolution was investigated by a combination of optical microscopy, X-ray diffraction, and electron backscattered diffraction methods. The microstructure of the as-Cast Strip consisted of ferrite matrix and martensite, and the texture was characterized by pronounced {001} 〈0vw〉 fiber texture in the outer layers and nearly random texture in the inner layers. After symmetric hot rolling, the microstructure was composed of deformed ferrite grains, proeutectoid ferrite grains and pearlite. The texture was characterized by pronounced {001} 〈0vw〉 fiber texture in the outer layers and mild γ-fiber texture in the inner layers. By contrast, when asymmetric hot rolling was applied, considerably dispersive proeutectoid ferrite and pearlite and relatively strong Goss texture were observed, together with strong {001} 〈0vw〉 fiber texture in the outer layers.