Effect of Tensile Deformation on the Grain Size of Annealed Grain Non-Oriented Electrical Steel

2009 ◽  
Vol 1243 ◽  
Author(s):  
J. Salinas B. ◽  
A. Salinas
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Annealing Temperature ◽  
Electrical Steel ◽  
Tensile Deformation ◽  
Strain Range ◽  
Final Annealing ◽  
Steel Sheets ◽  
Recrystallized Grain Size ◽  
Type Of Behavior

ABSTRACTAn experimental study on the effect of tensile deformation on recrystallized grain size has been carried out in order to establishing the optimal deformation needed to accelerate grain growth during final annealing of semi-processed non-oriented Si-Al, low C electrical steel sheets. The material is deformed in tension to strains from 3 to 20% and then air-annealed at temperatures between 700 and 900 °C. The results show that the critical deformation for recrystallization (8%) is independent of annealing temperature. However, the critical recrystallized grain size increases with annealing temperature from 160 to 240 μm. After that, the grain size decreases exponentially with increasing deformation. Abnormal grain growth is observed in samples annealed at 700 °C after strains in the range from 7 to 12%. This type of behavior is also observed in specimens annealed at 800 and 900 °C, however, in this case the pre-strain range is expanded to 3–12%. Normal grain growth is observed in samples pre-deformed to strains larger than 12%. In this case, the final grain size after 2 hour anneal is about 55 μm, also independent of annealing temperature. The possible implications of these results on the magnetic properties of these materials are discussed.

The Effect of Final Annealing Heating Rate on Abnormal Grain Growth in a Fe-3.5%Si Steel

2016 ◽  
Vol 879 ◽  
pp. 350-355
Author(s):  
Fatayalkadri Citrawati ◽  
Md Zakaria Quadir ◽  
Paul Munroe
Keyword(s):  
Grain Size ◽  
Heating Rate ◽  
Grain Growth ◽  
Growth Kinetics ◽  
Annealing Time ◽  
Annealing Temperature ◽  
Rapid Heating ◽  
Secondary Recrystallization ◽  
Recrystallization Annealing ◽  
Final Annealing

In this study the effects of heating rate on the sharpness and size of Goss oriented ({110}<001>) grains during secondary recrystallization annealing at 900 °C was observed. The results show that, at the same annealing temperature, rapid heating of the samples to this temperature generates a higher drag force compared to a slower heating rate (5°C/min). The two groups of samples show different growth kinetics for Goss grains, in which at the longest annealing time, the rapid heating sample exhibits larger maximum Goss grain size compared to the slower heated samples.

Mechanism of Grain Growth During Annealing of Si-Al Electrical Steel Strips Deformed in Tension

2010 ◽  
Vol 1276 ◽  
Author(s):  
J. Salinas B ◽  
A. Salinas R
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Electrical Steel ◽  
Electron Backscatter Diffraction ◽  
Steel Strip ◽  
Boundary Migration ◽  
Primary Recrystallization ◽  
Steel Strips ◽  
Grain Orientation Spread ◽  
Quality Maps

AbstractThe mechanism of recrystallization as a result of annealing during 600–7200 seconds at 700 °C of a Si-Al, low C electrical steel strip is investigated in samples deformed in tension. The evolution of grain size during annealing is evaluated by optical microscopy and electron backscatter diffraction in the scanning electron microscope. It is found that grain growth starts after an incubation time of 600 s with no apparent evidence of primary recrystallization. After that, the grain size-time relationship exhibits two different stages. Initially, the grain size increases linearly with time up to about 3600 s. During this time, some selected grains grow until they consume the deformed microstructure. In the second stage, the rate of growth decreases significantly and a final grain size of about 150 m is reached after 7200 seconds of annealing. Grain orientation spread maps obtained from EBSD data of deformed and partially recrystallized samples during the stage of linear growth reveals that the growing grains exhibit lower misorientation and therefore smaller stored energy than the non-recrystallized matrix grains. Analysis of image quality maps reveal that the IQ values for {100}<uvw>orientations are higher than those observed for {111}<uvw>orientations thus suggesting that the {100}<uvw>orientations grow at the expense of {111}<uvw>orientations by a mechanism of strain-induced boundary migration.

EBSD Study of Substructure and Texture Formation in Dual-Phase Steel Sheets for Semi-Finished Products

2010 ◽  
Vol 160 ◽  
pp. 251-256 ◽  
Author(s):  
M. Masimov ◽  
N. Peranio ◽  
B. Springub ◽  
Franz Roters ◽  
Dierk Raabe
Keyword(s):  
Cold Rolling ◽  
Annealing Temperature ◽  
Texture Evolution ◽  
Industrial Process ◽  
Dual Phase ◽  
Technological Parameters ◽  
Dual Phase Steels ◽  
Final Annealing ◽  
Steel Sheets ◽  
Different Temperatures

Using SEM/EBSD the substructure and texture evolution in dual phase steels in the first steps of the process chain, i.e. hot rolling, cold rolling, and following annealing were characterized. In order to obtain dual phase steels with high ductility and high tensile strength an industrial process was reproduced by cold rolling of industrially hot rolled steel sheets of a thickness of 3.75 mm with ferrite and pearlite morphology down to a thickness of 1.75 mm and finally annealing at different temperatures. Such technique allows a compilation of ferrite and martensite morphology typical for dual phase steels. Due to the competition between recovery, recrystallization and phase trans-formation during annealing a variety of ferrite martensite morphologies was produced by promoting one of the mechanisms through the variation of technological parameters such as heating rate, intercritical annealing temperature, annealing time, cooling rate and the final annealing temperature. Annealing induced changes of the mechanical properties were determined by hardness measurements and are discussed on the basis of the results of the substructure investigations.

Improving Brazeability of AA3003+Zn Brazing Aluminum Sheets by Final Annealing

2011 ◽  
Vol 197-198 ◽  
pp. 1555-1560 ◽  
Author(s):  
Yi You Tu ◽  
Xiang Liang Liu ◽  
Min Da Zhang ◽  
Jian Jun Zhang
Keyword(s):  
Grain Size ◽  
Annealing Temperature ◽  
Optical Microscope ◽  
Subgrain Structure ◽  
Intermediate Annealing ◽  
Test Rig ◽  
Final Annealing ◽  
Aluminum Sheets ◽  
Transmission Electron ◽  
Complete Recrystallization

Effect of intermediate annealing and final annealing on microstructures and properties of Al3003+Zn sheets is studied. The microstructure of aluminum sheets is observed by Optical Microscope and Transmission Electron Microscope，and the sagging resistance of aluminum sheets is tested by sagging test rig. The results indicate that complete recrystallization can be obtained after intermediate annealing at 380°C，and the recrystallization grain size of aluminum sheets reduces appreciably when annealing temperature rise. The sagging distance of aluminum sheets decreases proportionally with the grain size. Final annealing after final cold rolling eliminates subgrain structure of aluminum sheet, and improves sagging resistance of aluminum sheets observably.

Formation of Goss Texture in Grain Oriented Electrical Steel Sheets Produced by Commercial Compact Strip Processing

2010 ◽  
Vol 160 ◽  
pp. 241-246
Author(s):  
W. Mao ◽  
Y. Li ◽  
Z. An ◽  
G. Zhu ◽  
Ping Yang
Keyword(s):  
Hot Rolling ◽  
Electrical Steel ◽  
Low Cost ◽  
Secondary Recrystallization ◽  
High Angle ◽  
Goss Texture ◽  
Final Annealing ◽  
Electrical Steels ◽  
Steel Sheets ◽  
Electrical Steel Sheets

The compact strip processing technology and the technologies for conventional grain oriented electrical steels were used to process the low cost grain-oriented electrical steel successfully, in which the reheating temperature for hot rolling was about 1150 oC, and strong Goss texture was obtained after the secondary recrystallization. It is indicated that the density of inhibitor particles produced under the condition of low temperature hot rolling was high enough to induce the necessary secondary recrystallization during final annealing, so that many Goss grains could grow. The mis-orientations of Goss grains to the recrystallization matrix were calculated and observed. High angle boundaries enveloped frequently Goss grains, while the growth of other grains would have the possibility to meet low angle boundaries or low mobile boundaries. Goss grains neighboring larger size grains might be protected by the further precipitation of inhibitor particles in high angel boundaries during the temperature rising stage of the secondary recrystallization and survived somehow after the growth competition.

Effects of Annealing Parameters on Recrystallization of AZ31 Magnesium Alloy Processed by Continuous Rheo-Extrusion

2011 ◽  
Vol 239-242 ◽  
pp. 15-20
Author(s):  
Ren Guo Guan ◽  
Zhan Yong Zhao ◽  
Fu Rong Cao ◽  
Hong Qian Huang ◽  
Chun Guang Dai ◽  
...  
Keyword(s):  
Growth Rate ◽  
Magnesium Alloy ◽  
Grain Growth ◽  
Annealing Temperature ◽  
Holding Time ◽  
Az31 Magnesium Alloy ◽  
Dislocation Densities ◽  
Recrystallized Grain Size ◽  
Lower Temperature ◽  
Time Required

AZ31 magnesium alloy profiles were prepared by continuous rheo-extrusion, and effects of annealing temperature and time on recrystallization of AZ31 magnesium alloy were investigated. The results reveal that when the profile is annealed in the temperature range from 200°C to 300°C, the moving velocity of grain interface with different dislocation densities on both sides increases with increasing annealing temperature, which is favorable to the formation of crystallized nucleus in the region in which interface sweeps over. As a result, the time required by the accomplishment of recrystallization becomes short. After recrystallization finishes, continuous temperature rise or prolonged holding time result in grain growth. When the profile is annealed at elevated temperature, with the prolongation of holding time, the grain growth rate accelerates obviously, and hence recrystallized microstructure becomes coarse. When the profile is annealed at lower temperature, the grain growth rate becomes small, and the time required by the accomplishment of recrystallization is long, but recrystallized microstructure is fine and homogeneous. When the profile is annealed at 250°C for 4h, average recrystallized grain size is 15μm.

Recrystallisation, Grain Growth and Texture Evolution in Nonoriented Electrical Steels

2007 ◽  
Vol 558-559 ◽  
pp. 657-664 ◽  
Author(s):  
Jong Tae Park ◽  
Jae Kwan Kim ◽  
Jerzy A. Szpunar
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Grain Growth ◽  
Texture Evolution ◽  
Size Control ◽  
Goss Texture ◽  
Final Annealing ◽  
Electrical Steels ◽  
Grain Size Control ◽  
Specific Orientation

The magnetic properties of nonoriented electrical steels are influenced by grain size and texture of final products. The key technology in the commercial production of nonoriented electrical steels is to grow grains with {hk0}<001> texture up to the optimum size in the final annealing process. The problems related to grain size control have been extensively investigated, while texture control has received much less attention. Therefore, there is enough room to improve the magnetic properties through the control of texture. In this study, systematic investigations on the texture evolution during both recrystallization and grain growth have been made. The formation of recrystallization texture is explained by oriented nucleation. This is supported by the fact that the area fraction of nuclei or recrystallized grains with specific orientation to all new grains remains almost constant during the progress of recrystallization. Most nuclei have a high misorientation angle of 25∼55° with the surrounding deformed matrices. During the progress of grain growth, the Goss texture component continues to decrease because the Goss grains have a high percentage of low angle, low mobility grain boundaries. The grains of Goss orientation have a smaller grain size than those of random orientation.

Influence of Heating Rate and Decarburization Temperature on the Microstructure and Magnetic Properties of Grain Oriented Electrical Steel

2012 ◽  
Vol 706-709 ◽  
pp. 2622-2627 ◽  
Author(s):  
Chun Kan Hou ◽  
Jian Ming Tzeng
Keyword(s):  
Magnetic Properties ◽  
Heating Rate ◽  
Grain Growth ◽  
Electrical Steel ◽  
Rapid Heating ◽  
Abnormal Grain Growth ◽  
Heating Rates ◽  
Abnormal Growth ◽  
Steel Sheets ◽  
Microstructure And Magnetic Properties

Effects of three heating rates, 5, 20/min., and 300°C/sec and decarburization temperature, 700-850°C in primary annealing on the microstructure and magnetic properties of a grain oriented electrical steel were investigated. It was found that the oxide layer thickness and grain size increased with increasing decarburization temperature. However, they decreased with increasing heating rate. On the other hand, injection nitrogen content into steel sheets decreased with increasing decarburization temperature. The percentage of abnormal grain growth obtained a peak value at 800°C in the specimens treated with heating rate less than 20°C per minute. But specimens with rapid heating rate, percentage of abnormal grain growth increased with increasing decarburization temperature. As percentage of abnormal growth increased, magnetic properties got better.

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