scholarly journals Precipitates in Compact Strip Production (CSP) Process Non-Oriented Electrical Steel

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1301
Author(s):  
Jia-long Qiao ◽  
Fei-hu Guo ◽  
Jin-wen Hu ◽  
Li Xiang ◽  
Sheng-tao Qiu ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Grain Growth ◽  
Electrical Steel ◽  
Volume Fraction ◽  
Precipitation Mechanism ◽  
Compact Strip Production ◽  
Transmission Electron ◽  
Average Size ◽  
Strip Production

Nitrogen and Sulfur in non-oriented electrical steel would form precipitates, which would severely affect its magnetic properties. Precipitates in compact strip production (CSP) process non-oriented electrical steel were investigated using a transmission electron microscope (TEM) and scanning electron microscopy (SEM). The precipitation mechanism and influence on grain growth were analyzed experimentally and theoretically. The results showed that the main particles in steel were AlN, TiN, MnS, Cu2S, and fine oxide inclusions. The spherical or quasi-spherical of MnS and Cu2S were more liable to precipitate along grain boundaries. During the soaking process, the amount of MnS precipitated on the grain boundary was much larger than that of Cu2S. AlN and TiN in cubic shape precipitated inside grains or grain boundaries. Precipitates preferentially nucleated at grain boundaries, and TiN, MnS mainly precipitated during soaking. In the subsequent processes after soaking, AlN and Cu2S would precipitate unceasingly with the decrease in the average size. The distribution density, the volume fraction, and the average size of the precipitates in the annealed sheets were 9.08 × 1013/cm3, 0.06%, and 54.3 nm, respectively. Precipitates with the grain size of 30–500 nm hindered the grain growth, the grains with 100–300 nm played a major role in inhibiting the grain growth, and the grains with the grain size of 70–100 nm took the second place.

scholarly journals Optimum Magnetic Properties of Non-Oriented Electrical Steel Produced by Compact Strip Production Process

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 64
Author(s):  
Junqiang Cong ◽  
Feihu Guo ◽  
Jialong Qiao ◽  
Shengtao Qiu ◽  
Haijun Wang
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Electrical Steel ◽  
Volume Fraction ◽  
Core Loss ◽  
Optical Microscope ◽  
Magnetic Flux Density ◽  
Magnetization Direction ◽  
Compact Strip Production ◽  
Strip Production

Optimum grain size and effects of crystallographic textures on magnetic properties of Fe-0.65%Si non-oriented electrical steel produced by compact strip production (CSP) process were investigated by optical microscope, electron backscatter diffraction (EBSD), and X-ray diffraction (XRD) techniques. Magnetic induction and core loss show a decreasing trend with the increase of grain size, and grain sizes for optimal magnetic properties are in the range of 26–30 μm. Core loss would be mainly affected by grain size, whereas crystallographic texture would primarily affect magnetic flux density. Magnetic properties increase with increasing of texture factor (volume fraction ratio of {100}/{111}) and magnetic texture factor (volume fraction ratio of <100>/<111>), and increasing with the decrease of A-parameter (minimum angle between magnetization direction and the closest <100> direction) and A(h→), respectively. Simultaneously, with increasing of A-parameter and A(h→), a linear decrease of B50 was obtained.

scholarly journals Microstructure and Microtexture Development in Grain Oriented Electrical Steel

2021 ◽  
Author(s):  
◽  
Ali Nadoum
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Heating Rate ◽  
Grain Growth ◽  
Electrical Steel ◽  
Flow Direction ◽  
Rolling Direction ◽  
Magnetic Domain ◽  
Abnormal Grain Growth ◽  
Heat Flow Direction

The first Si-Fe electrical steel was produced in 1905, and the grain-oriented steel was discovered in 1930 after Goss demonstrated how optimal combinations of heat treatment and cold rolling could produce a texture giving Si-Fe strip good magnetic properties when magnetised along its rolling direction. This technology has reduced the power loss in transformers greatly and remains the basis of the manufacturing process today. Since then, many postulations reported on the mechanism on abnormal grain growth (AGG) which is the key for Si-Fe superior magnetic properties. However, none have provided a concrete understanding of this phenomenon. Identifying and classifying the driving force behind Goss abnormal grain growth is of industrial and academic importance to further optimise the manufacturing process and reduce losses. In the current investigation, the deviation from easy magnetisation direction <001> was studied to find a correlation between crystallographic orientation and magnetic domain structure. Both deviation angles α: the angle between <001> and in-plane rolling direction (RD), and β: the angle between <001> and out-plane rolling direction were calculated using electron backscatter diffraction (EBSD) raw data. Further, EBSD combined with forescatter detector (FSD) is used to reveal the magnetic domain configuration within individual oriented grains. The magnetic domain patterns were directly imaged and correlated to the crystal orientation and α and β deviation angles. It was demonstrated that the size of the deviated orientation grains from ideal (110) <001> Goss orientation is a critical microtexture parameter for the optimisation of magnetic property. It is concluded that the magnetic domain patterns and α and β angle of deviations are strongly correlated to the magnetic losses in GOES (grain oriented electrical steel).Furthermore, the effect of grain boundaries, grain size, heating rate and dislocation density on Goss abnormal grain growth was investigated using EBSD. It was found that in the early stages of secondary recrystallisation random grains grow and abnormal growth of Goss achieved in low heating rate. The advantage of Goss abnormal grain growth in secondary recrystallisation is lost while annealing at a high heating rate, and random orientation can grow abnormally. Also, statistical analysis of grain boundaries, including CSL (coincident site lattice), shows no distinct behaviour and high angle grain boundaries and CSL are not exclusive to Goss oriented grains. In addition, GND (geometrically necessary dislocation) and Taylor Factor showed to be randomly distributed around Goss grains, and the hypothesis of Goss grains grow by consuming high GND and Taylor Factor grains cannot be the reason for Goss abnormal grain growth. Neutron diffraction experiment was conducted at Rutherford Appleton Laboratory, ISIS facility at Oxford, UK using GEM beamline. It was demonstrated that Si atom positions in the solid solution disorder α-Fe cubic unit cell that cause lattice distortions and BCC symmetry reduction is the most influential factor in early stages of Goss AGG than what was previously thought to be dislocation related stored energy, grain boundary characteristics and grain size/orientation advantages. Finally, heat flux, heat flow direction, and strain effect on Goss abnormal grain growth investigated. It was found that heat flow direction greatly impacts the rate of abnormal grain growth of Goss. Also, strain areas can disrupt Goss AGG and promotes randomly oriented grains to grow abnormally.

Research on Key Technology of Normal Grain Growth for Second Phase Particle Materials by Cellular Automata Simulation

2012 ◽  
Vol 510 ◽  
pp. 772-775
Author(s):  
Zong Lei Gu ◽  
Yu Liang Yin
Keyword(s):  
Grain Size ◽  
Cellular Automata ◽  
Grain Boundaries ◽  
Grain Growth ◽  
Volume Fraction ◽  
Phase Particle ◽  
Second Phase ◽  
Pinning Mechanism ◽  
Simulation Results ◽  
Single Size

Based on cellular automata, a model of simulating grain growth was established and the key technologies of simulation was studied which including second phase particle of single size, multi-size distribution and different shapes generation technologies. The simulation result can accurately reflect the influence law of the second phase particle grain growth and its pinning mechanism. Grain boundaries can therefore more easily break free from the particles than in purely two-dimensional systems, resulting in fewer grain boundaryparticle intersections and a larger final grain size. For a given volume fraction f and size of the particles r, the final grain size increases with film thickness. Moreover, it was found that particles located in the middle of the film are most efficient in pinning grain boundaries. The simulation results are compared with Zener type relations and previous simulation results.

scholarly journals Texture Evolution during Recrystallization and Grain Growth in Non-Oriented Electrical Steel Produced by Compact Strip Production Process

Materials ◽  
2021 ◽  
Vol 15 (1) ◽  
pp. 197
Author(s):  
Jun-Qiang Cong ◽  
Fei-Hu Guo ◽  
Jia-Long Qiao ◽  
Sheng-Tao Qiu ◽  
Hai-Jun Wang
Keyword(s):  
Grain Growth ◽  
Electrical Steel ◽  
Texture Evolution ◽  
Fiber Texture ◽  
Rolled Sheet ◽  
Recrystallization Process ◽  
Columnar Crystal ◽  
Compact Strip Production ◽  
Cold Rolled ◽  
Strip Production

Evolution of texture and α*-fiber texture formation mechanism of Fe-0.65%Si non-oriented electrical steel produced by Compact Strip Production (CSP) process during all the thermo-mechanical processing steps were investigated using electron backscatter diffraction (EBSD) and X-ray diffraction (XRD) techniques. Columnar crystal structure of cast slab is fine and well-developed. Textures of the hot-rolled band are quite different in the thickness direction. During annealing of cold-rolled sheet, γ-fiber texture grains would nucleate and grow preferentially, and α*-fiber texture grains mainly nucleate and grow in the shear zone of α-fiber texture of cold-rolled sheet. During the recrystallization process, γ-fiber texture gradually concentrated to {111}<112>, and γ and α*-fiber texture increased significantly. {111}<112> texture priority nucleation at the initial stage of recrystallization. Due to the advantages of nucleation position and quantity, the content of α*-fiber texture is greater than {111}<112> texture in the mid-recrystallization. During grain growth process, {111}<112> oriented grains would grow selectively by virtue of higher mobility, sizes and quantity advantages than that of {411}<148 > and {100}<120>, resulting in the gradual increase of γ-fiber texture and the decline of α *-fiber texture.

Grain Refinement in Titanium-Erbium Alloys

1974 ◽  
Vol 32 ◽  
pp. 522-523
Author(s):  
B. B. Rath ◽  
J. E. O'Neal ◽  
R. J. Lederich
Keyword(s):  
Electron Microscopy ◽  
Size Distribution ◽  
Grain Refinement ◽  
Grain Growth ◽  
Volume Fraction ◽  
Pure Titanium ◽  
Systematic Investigation ◽  
Second Phase ◽  
Titanium Matrix ◽  
Average Size

Addition of small amounts of erbium has a profound effect on recrystallization and grain growth in titanium. Erbium, because of its negligible solubility in titanium, precipitates in the titanium matrix as a finely dispersed second phase. The presence of this phase, depending on its average size, distribution, and volume fraction in titanium, strongly inhibits the migration of grain boundaries during recrystallization and grain growth, and thus produces ultimate grains of sub-micrometer dimensions. A systematic investigation has been conducted to study the isothermal grain growth in electrolytically pure titanium and titanium-erbium alloys (Er concentration ranging from 0-0.3 at.%) over the temperature range of 450 to 850°C by electron microscopy.

The Effect of Grain Size on Superplastic Deformation of Ti-6Al-4V Alloy

2007 ◽  
Vol 551-552 ◽  
pp. 387-392 ◽  
Author(s):  
Wen Juan Zhao ◽  
Hua Ding ◽  
D. Song ◽  
F.R. Cao ◽  
Hong Liang Hou
Keyword(s):  
Grain Size ◽  
Grain Growth ◽  
Superplastic Deformation ◽  
Initial Strain Rate ◽  
Deformation Mode ◽  
Tensile Tests ◽  
Optical Microscope ◽  
Coarse Grained ◽  
Transmission Electron ◽  
Grain Growth Model

In this study, superplastic tensile tests were carried out for Ti-6Al-4V alloy using different initial grain sizes (2.6 μm, 6.5μm and 16.2 μm) at a temperature of 920°C with an initial strain rate of 1×10-3 s-1. To get an insight into the effect of grain size on the superplastic deformation mechanisms, the microstructures of deformed alloy were investigated by using an optical microscope and transmission electron microscope (TEM). The results indicate that there is dramatic difference in the superplastic deformation mode of fine and coarse grained Ti-6Al-4V alloy. Meanwhile, grain growth induced by superplastic deformation has also been clearly observed during deformation process, and the grain growth model including the static and strain induced part during superplastic deformation was utilized to analyze the data of Ti-6Al-4V alloy.

Shape Memory Characteristics and Superelasticity of Ti-Ni-Cu Alloy Ribbons with Nano Ti2Ni Particles

2008 ◽  
Vol 8 (2) ◽  
pp. 722-727 ◽  
Author(s):  
Tae-hyun Nam ◽  
Cheol-am Yu ◽  
Jung-min Nam ◽  
Hyun-gon Kim ◽  
Yeon-wook Kim
Keyword(s):  
Melt Spinning ◽  
Volume Fraction ◽  
Deformation Behaviour ◽  
Parent Phase ◽  
Tensile Tests ◽  
Constant Load ◽  
Cu Alloy ◽  
Transmission Electron ◽  
Average Size ◽  
Memory Characteristics

Microstructures and deformation behaviour of Ti-45Ni-5Cu and Ti-46Ni-5Cu alloy ribbons prepared by melt spinning were investigated by transmission electron microscopy, thermal cycling tests under constant load and tensile tests. Spherical Ti2Ni particles coherent with the B2 parent phase were observed in the alloy ribbons when the melt spinning temperature was higher than 1773 K. Average size of Ti2Ni particles in the ribbons obtained at 1873 K was 8 nm, which was smaller than that (10 nm) in the ribbons obtained at 1773 K. Volume fraction of Ti2Ni phase in the ribbons obtained at 1873 K was 40%, which was larger than that (20%) in the ribbons obtained at 1773 K. The stress required at temperatures of Af + 10 K for the stress-induced martensitic transformation increased from 93 MPa to 229 MPa and apparent elastic modulus of the B2 parent phase increased from 56 GPa to 250 GPa with increasing the melt spinning temperature from 1673 K to 1873 K in Ti-45Ni-5Cu alloy ribbons. The critical stress for slip deformation of the ribbons increased by coherent Ti2Ni particles, and thus residual elongation did not occur even at 160 MPa, while considerable plastic deformation occurred at 60 MPa in the ribbons without Ti2Ni particles. Almost perfect superelastic recovery was found in the ribbons with coherent Ti2Ni particles, while only partial superelastic recovery was observed in the ribbons without coherent Ti2Ni particles.

scholarly journals Microstructure and Mechanical Properties of 4Al Alumina-Forming Austenitic Steel after Cold-Rolling Deformation and Annealing

Materials ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 2767 ◽  
Author(s):  
Chenchen Jiang ◽  
Qiuzhi Gao ◽  
Hailian Zhang ◽  
Ziyun Liu ◽  
Huijun Li
Keyword(s):  
Grain Size ◽  
Cold Rolling ◽  
Grain Boundaries ◽  
Austenitic Steel ◽  
Rolling Reduction ◽  
X Ray Diffraction ◽  
Transmission Electron ◽  
Cold Rolling Reduction ◽  
Average Grain Size ◽  
Cold Rolled

Microstructural evolutions of the 4Al alumina-forming austenitic steel after cold rolling with different reductions from 5% to 30% and then annealing were investigated using electron backscattering diffraction (EBSD), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Tensile properties and hardness were also measured. The results show that the average grain size gradually decreases with an increase in the cold-rolling reduction. The low angle grain boundaries (LAGBs) are dominant in the cold-rolled samples, but high angle grain boundaries (HAGBs) form in the annealed samples, indicating that the grains are refined under the action of dislocations. During cold rolling, high-density dislocations are initially introduced in the samples, which contributes to a large number of dislocations remaining after annealing. With the sustaining increase in cold-rolled deformation, the samples exhibit more excellent tensile strength and hardness due to the decrease in grain size and increase in dislocation density, especially for the samples subjected to 30% cold-rolling reduction. The contribution of dislocations on yield strength is more than 60%.

scholarly journals Enhanced Mechanical Properties of Mg-6Sn-3Al-1Zn Alloy with Bimodal Grain Size Disturbed in the Microstructure Uniformly through Changing the Rolling Temperature

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Fuan Wei ◽  
Jinhui Wang ◽  
Ping Li ◽  
Bo Shi
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Yield Strength ◽  
Volume Fraction ◽  
Rolling Temperature ◽  
Average Grain Size ◽  
Small Grains ◽  
Mg2sn Phase ◽  
Average Size ◽  
Bimodal Grain Size

The mechanical properties of Mg-6Sn-3Al-1Zn alloy were enhanced with bimodal grain size disturbed in the microstructure uniformly; the Mg-6Sn-3Al-1Zn alloys were rolled with 60% thickness reduction at different rolling temperatures. The results have shown that the Mg-6Sn-3Al-1Zn alloys are composed of Mg2Sn phase and α-Mg matrix phase. When the rolling temperature was less than or equal to 400°C, with the rolling temperature increasing, the average size and volume fraction of Mg2Sn phase and the average grain size of small grains remained unchanged, the average grain size of large grains decreased, the volume fraction of small grains increased, and the yield strength of the alloy increased. When the rolling temperature reached 450°C, the average size and volume fraction of Mg2Sn phase and the average grain size of large grains increased, and the volume fraction of small grains and the yield strength of the alloy decreased. The elongation increased with the rolling temperature increasing, but the change trend of hardness was just opposite. When the alloy was rolled at 400°C, the average sizes of small grains, large grains, and Mg2Sn phases were 3.66 μm, 9.24 μm, and 19.5 μm, respectively. The volume fractions of small grains, large grains, and Mg2Sn phases were 18.6%, 77.6%, and 3.8%, respectively. And the tensile properties reached the optimum; for example, the tensile strength, yield strength, elongation, and Vickers hardness were 361 MPa, 289.5 MPa, 20.5%, and 76.3 HV, respectively.

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