scholarly journals Evolution of Power Losses in Bending Rolled Fully Finished NO Electrical Steel Treated under Unconventional Annealing Conditions

Materials ◽  
2019 ◽  
Vol 12 (13) ◽  
pp. 2200 ◽  
Author(s):  
Ivan Petryshynets ◽  
František Kováč ◽  
Ján Füzer ◽  
Ladislav Falat ◽  
Viktor Puchý ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Grain Growth ◽  
Electrical Steel ◽  
Magnetic Measurements ◽  
Boundary Migration ◽  
Stress Relief ◽  
Rolling Process ◽  
Deformation Energy ◽  
Conventional Heat Treatment ◽  
Dynamic Heating

Currently, the non-oriented (NO) iron-silicon steels are extensively used as the core materials in various electrical devises due to excellent combination of their mechanical and soft magnetic properties. The present study introduces a fairly innovative technological approach applicable for fully finished NO electrical steel before punching the laminations. It is based on specific mechanical processing by bending and rolling in combination with subsequent annealing under dynamic heating conditions. It has been revealed that the proposed unconventional treatment clearly led to effective improvement of the steel magnetic properties thanks to its beneficial effects involving additional grain growth with appropriate crystallographic orientation and residual stress relief. The philosophy of the proposed processing was based on employing the phenomena of selective grain growth by strain-induced grain boundary migration and a steep temperature gradient through the cross-section of heat treated specimens at dynamic heating conditions. The stored deformation energy necessary for the grain growth was provided by plastic deformation induced within the studied specimens during the bending and rolling process. The magnetic measurements clearly show that the specimens treated according to our approach exhibited more than 17% decrease in watt losses in comparison with the specimens treated by conventional heat treatment leading only to stress relief without additional grain growth.

The Research of Non-Oriented Electrical Steel Processed by Stress Relief Annealing Experiments

2014 ◽  
Vol 887-888 ◽  
pp. 252-256
Author(s):  
Zhun Li ◽  
Jing Liu ◽  
Shi De Li ◽  
Ze Lin Zheng
Keyword(s):  
Magnetic Properties ◽  
Electrical Steel ◽  
Core Loss ◽  
Reference Method ◽  
Stress Relief ◽  
Hydrogen Atmosphere ◽  
Silicon Steel ◽  
Pure Hydrogen ◽  
Final Annealing ◽  
Annealing Experiments

A high grade non-oriented electrical steel final annealing product was processed by stress relief annealing experiments under pure hydrogen atmosphere using different process parameters. The samples were compared in the aspects of magnetic properties and anisotropy, then analyzed the phenomena concerned with grain size, texture and precipitates aspects. The experiments showed that the samples magnetic properties were most improved in the 850 degrees stress relief annealing experiment, thus providing a reference method for non-oriented silicon steel stress relief annealing experiments and to obtain low core loss non-oriented silicon steel.

scholarly journals Improving the Magnetic Properties of Non-Oriented Electrical Steels by Secondary Recrystallization Using Dynamic Heating Conditions

Materials ◽  
2019 ◽  
Vol 12 (12) ◽  
pp. 1914 ◽  
Author(s):  
Ivan Petryshynets ◽  
František Kováč ◽  
Branislav Petrov ◽  
Ladislav Falat ◽  
Viktor Puchý
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Boundary Migration ◽  
Cold Work ◽  
Secondary Recrystallization ◽  
Coarse Grained ◽  
High Heating Rate ◽  
Electrical Steels ◽  
Heat Treated ◽  
Dynamic Heating

In the present work, we have used unconventional short-term secondary recrystallization heat treatment employing extraordinary high heating rate to develop coarse-grained microstructure with enhanced intensity of rotating cube texture {100}<011> in semi-finish vacuum degassed non-oriented electrical steels. The soft magnetic properties were improved through the increase of grains size with favourable cube crystallographic orientation. The appropriate final textural state of the treated experimental steels was achieved by strain-induced grain boundary migration mechanism, activated by gradient of accumulated stored deformation energy between neighbouring grains after the application of soft cold work, combined with steep temperature gradient during subsequent heat treatment under dynamic heating conditions. The materials in our experimentally prepared material states were mounted on the stator and rotor segments of electrical motors and examined for their efficiency in real operational conditions. Moreover, conventionally long-term heat treated materials, prepared in industrial conditions, were also tested for reference. The results show that the electrical motor containing the segments treated by our innovative approach, exhibits more than 1.2% higher efficiency, compared to the motor containing conventionally heat treated materials. The obtained efficiency enhancement can be directly related to the improved microstructural and textural characteristics of our unconventionally heat treated materials, specifically the homogenous coarse grained microstructure and the high intensity of cube and Goss crystallographic texture.

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.

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.

scholarly journals Grain Growth Mechanism of Lamellar-Structure High-Purity Nickel via Cold Rolling and Cryorolling during Annealing

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4025
Author(s):  
Zhide Li ◽  
Yuze Wu ◽  
Zhibao Xie ◽  
Charlie Kong ◽  
Hailiang Yu
Keyword(s):  
Grain Growth ◽  
Growth Mechanism ◽  
High Purity ◽  
Lamellar Structure ◽  
Room Temperature ◽  
Rolling Process ◽  
Deformation Energy ◽  
Different Temperatures ◽  
Continuous Recrystallization ◽  
Room Temperature Rolling

High-purity (99.999%) nickel with lamellar-structure grains (LG) was obtained by room-temperature rolling and cryorolling in this research, and then annealed at different temperatures (75 °C, 160 °C, and 245 °C). The microstructure was characterized by transmission electron microscopy. The grain growth mechanism during annealing of the LG materials obtained via different processes was studied. Results showed that the LG high-purity nickel obtained by room-temperature rolling had a static discontinuous recrystallization during annealing, whereas that obtained by cryorolling underwent static and continuous recrystallization during annealing, which was caused by the seriously inhibited dislocation recovery in the rolling process under cryogenic conditions, leading to more accumulated deformation energy storage in sheets.

Characterization of Electron Beam Welded Non-Oriented Electrical Steel with Magnetic Barkhausen Noise

2014 ◽  
Vol 605 ◽  
pp. 39-42 ◽  
Author(s):  
Polykseni Vourna
Keyword(s):  
Mechanical Properties ◽  
Magnetic Properties ◽  
Electron Beam ◽  
Electrical Steel ◽  
Electron Beam Welding ◽  
Magnetic Measurements ◽  
Barkhausen Noise ◽  
Magnetic Barkhausen Noise ◽  
Electrical Steels

In this paper the influence of Electron Beam Welding (EBW) on the microstructure, mechanical and magnetic properties of Non-Oriented Electrical steels was presented and evaluated. Single pass welds free of defects were produced at welding speeds and pulsed currents following a predesigned protocol. The samples microstructure and the macrohardness tests were concluded with the magnetic measurements (Barkhausen Noise) in order to correlate the structural and mechanical properties with the magnetizing behavior of Non-Oriented Electrical Steel.

Texture Change during Grain Growth in Non-Oriented Electrical Steel

2012 ◽  
Vol 715-716 ◽  
pp. 33-40 ◽  
Author(s):  
Y. Arita ◽  
L. Chan ◽  
S.D. Sintay ◽  
Anthony D. Rollett
Keyword(s):  
Computer Simulation ◽  
Grain Size ◽  
Magnetic Properties ◽  
Cold Rolling ◽  
Grain Growth ◽  
Electrical Steel ◽  
Experimental Result ◽  
New Approach ◽  
Texture Change ◽  
Texture Sample

Grain size and texture are very important for controlling the magnetic properties in non-oriented electrical steel. Grain size and texture are closely related because the texture usually changes during grain growth. In this study, texture changes with grain growth in non-oriented electrical steel are investigated. Two kinds of materials, Sample A and Sample B, were prepared in order to study the differences of the texture. Sample A, Fe-0.5wt%Si, is not annealed before cold rolling. Sample B, the same chemical composition as Sample A, is annealed before cold rolling. In Sample A, the {111} texture component increases markedly during grain growth. By contrast, in Sample B, the increase in {111} is less pronounced. The recrystallized orientations in both Samples are analyzed, and computer simulation is used to attempt to explain the texture changes during grain growth. In the case of Sample A, the simulations reproduce the experimental result well; for Sample B, however, the simulations do not agree as well. The microstructures before annealing exhibit strong alignment of the orientations, which will require a new approach to building the digital microstructures for instantiation of the simulations.

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