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.

Structure and Hardness of Cryorolled and Heat-Treated 2xxx Aluminum Alloy

2010 ◽  
Vol 667-669 ◽  
pp. 925-930
Author(s):  
S.V. Krymskiy ◽  
Elena Avtokratova ◽  
M.V. Markushev ◽  
Maxim Yu. Murashkin ◽  
O.S. Sitdikov
Keyword(s):  
Heat Treatment ◽  
Solid Solution ◽  
Plastic Deformation ◽  
Aluminum Alloy ◽  
Severe Plastic Deformation ◽  
Coarse Grained ◽  
Aging Response ◽  
Heat Treated ◽  
Aluminum Solid Solution ◽  
A Cell

The effects of severe plastic deformation (SPD) by isothermal rolling at the temperature of liquid nitrogen combined with prior- and post-SPD heat treatment, on microstructure and hardness of Al-4.4%Cu-1.4%Mg-0.7%Mn (D16) alloy were investigated. It was found no nanostructuring even after straining to 75%. Сryodeformation leads to microshear banding and processing the high-density dislocation substructures with a cell size of ~ 100-200 nm. Such a structure remains almost stable under 1 hr annealing up to 200oC and with further temperature increase initially transforms to bimodal with a small fraction of nanograins and then to uniform coarse grained one. It is found the change in the alloy post–SPD aging response leading to more active decomposition of the preliminary supersaturated aluminum solid solution, and to the alloy extra hardening under aging with shorter times and at lower temperatures compared to T6 temper.

The Effect of Incomplete Solution Treatment on the Tensile Behavior and Mechanical Anisotropy of 2195 Aluminum Lithium Alloy

2019 ◽  
Vol 22 ◽  
pp. 109-117
Author(s):  
Wesley Walker ◽  
Rudolf Marloth ◽  
Ye Thura Hein ◽  
Omar S. Es-Said
Keyword(s):  
Heat Treatment ◽  
Treatment Time ◽  
Cold Work ◽  
Rolling Direction ◽  
Solution Treatment ◽  
Tensile Behavior ◽  
Mechanical Anisotropy ◽  
Aluminum Lithium Alloy ◽  
Heat Treated ◽  
Aluminum Lithium

This study aimed to characterize the effects of incomplete solution treatment time on the tensile behavior of 2195 Al-Li alloy. Two sets of plates of 2195 Al-Li alloy received solution heat treatment. One set received the prescribed treatment, held in the furnace for 30 minutes after the material had reached 507°C. The other set was in the furnace for only 30 minutes and did not reach 507°C until after about 15 to 20 minutes. Both set of plates were water quenched. Samples from the plates were then stretched 2.5-3% or 6%, rolled 6%, and rolled 24%, at 0°, 45°, and 90° relative to the rolling direction of the as-received material. The samples were aged at 143°C for 36 hours and air-cooled. Tensile specimens were milled out at 0°, 45°, and 90° relative to the original rolling direction. Tensile testing was performed on all samples. The incomplete heat treatment (incomplete solution treatment) resulted in a significant reduction in strength. This was probably due to the formation of fewer T1 precipitates after aging, thereby reducing the amount which could nucleate during cold work. The fully heat treated samples had higher percent yield strength, ultimate strength, and elongation.

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.

Effect of Heat Treatment on Microstructure and Magnetic Properties of Strontium Hexaferrite Nanoparticles Prepared in Presence of Non-Ionic Surfactant

2013 ◽  
Vol 202 ◽  
pp. 193-205
Author(s):  
Nital R. Panchal ◽  
Rajshree B. Jotania
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Tween 80 ◽  
Strontium Hexaferrite ◽  
Ionic Surfactant ◽  
Treatment Conditions ◽  
Heat Treated ◽  
Higher Temperature ◽  
Co Precipitation ◽  
Microstructure And Magnetic Properties

SrFe12O19 hexaferrite particles containing polyoxyethelene (20) sorbitan monolate (Tween-80) were synthesized by a chemical co-precipitation technique with a precipitator NH3.H2O. The prepared Sr-M hexaferrite precipitates were heat treated at various temperatures 650 oC, 750 oC, 850 oC, 950oC and 1100oC for 4 hrs in a muffle furnace. The obtained Sr-M powders were characterized by using various instrumental techniques, like FTIR, TGA, XRD, SEM, VSM and Mössbauer spectroscopy. Their physical as well as Magnetic properties were compared. It was observed from XRD results that heat treatment conditions play significant role in the formation of pure SrFe12O19 hexaferrite phase and also in the grain size. The estimated particle size is of the order of nanometer when suitable calcination temperature is applied. SEM micrographs show an increase in crystallite size of the resultant SrFe12O19 hexaferrite particles sintered at higher temperature (1100 oC). Mössbauer spectroscopic measurements were carried out at room temperature. Mössbauer analysis indicates the presence Fe3+ ions in the prepared strontium hexaferrite particles.

Orientation of Island and Small Grains in Grain Oriented Electrical Steels

2013 ◽  
Vol 753 ◽  
pp. 530-533
Author(s):  
Jong Tae Park ◽  
Hyun Seok Ko ◽  
Hyung Don Joo ◽  
Dae Hyun Song ◽  
Kyung Jun Ko ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Grain Boundary ◽  
Magnetic Flux ◽  
Core Loss ◽  
Secondary Recrystallization ◽  
Magnetic Flux Density ◽  
Recrystallization Annealing ◽  
Goss Texture ◽  
Electrical Steels ◽  
Small Grains

Grain oriented electrical steels should have low core loss and high magnetic flux density. These properties are closely related with sharpness of {110} texture after secondary recrystallization. This Goss texture develops by abnormal grain growth during secondary recrystallization annealing. Based on experimental results, a general suggestion which estimates the magnetic properties after secondary recrystallization from a primary recrystallized texture can be made. For a material to have better magnetic properties after secondary recrystallization, its primary recrystallized texture should have not only larger number of ideal Goss grains, but also lower frequency of low angle grain boundary around those Goss grains.

Influence of Thickness on Magnetic and Microstructural Properties in Electrical Steels Semi-Processed of Low Efficiency

2018 ◽  
Vol 930 ◽  
pp. 466-471
Author(s):  
M.A. Trindade ◽  
Marcos Flavio de Campos ◽  
Fernando José Gomes Landgraf ◽  
Nelson Batista de Lima ◽  
A. Almeida
Keyword(s):  
Heat Treatment ◽  
Grain Size ◽  
Magnetic Properties ◽  
Silicon Content ◽  
Static Condition ◽  
Magnetic Losses ◽  
Microstructural Properties ◽  
Electrical Steels ◽  
Wet Heat ◽  
Low Efficiency

In this study, a steel for semiprocessed electrical purposes of non-oriented grain with approximately 0.05% carbon content and 0.02% silicon content was evaluated. Lamellas with kind of thicknesses 0.58 mm, 0,66 mm and 0.87 mm were processed on an industrial scale with a strain rate in the hardening lamination between 3 and 5%. The magnetic properties were evaluated after the wet heat treatment. The loss separation method was applied, estimating the hysteretic plot with hysteresis measure in the quasi static condition and the parasitic losses calculated according to Thomson's Equation. By increasing grain size, permeability increases and coercivity decreases. However, in the case of losses, there is an optimum grain size. After the procedure of separation of losses, it was observed that increase of thickness results in increase of the anomalous parcel of magnetic losses.

The Effect of PWHT on the Material Properties and Micro Structure in Inconel 625 and Inconel 725 Buttered Joints

2003 ◽  
Author(s):  
Vigdis Olden ◽  
Per Egil Kvaale ◽  
Per Arne Simensen ◽  
Synno̸ve Aaldstedt ◽  
Jan Ketil Solberg
Keyword(s):  
Heat Treatment ◽  
Impact Toughness ◽  
Post Weld Heat Treatment ◽  
Fusion Line ◽  
Coarse Grained ◽  
Inconel 625 ◽  
Micro Structure ◽  
Mixed Zone ◽  
Heat Treated ◽  
Weld Heat

This report describes investigations performed on as welded and post weld heat treated samples of AISI 8630 steel, buttered with Inconel 625 and Inconel 725. The investigations have focused on the properties and microstructure in the partial mixed zone between the buttering and the steel before and after post weld heat treatment. The samples were heat treated for 4 1/2 hours at 640°C, 665° and 690°C and investigated with respect to mechanical properties and microstructure near the fusion line. A range of testing and analyses were performed including notch impact toughness testing, identification of fracture initiation and propagation in impact specimens, hydrogen measurements, examination of the micro structure in steel and Inconel using light microscope, hardness testing and electron micro-probe analysis of the alloying elements across the fusion line. Additional investigations in TEM on samples from an actual joint, post weld heat treated at 665°C were also performed. The results show that post weld heat treatment at 665°C and 690°C reduced the impact toughness in coarse grained heat affected zone, caused by decarburisation, ferrite formation and grain growth. The partially mixed zone (5–10μm) of the Inconel buttering, gained partly extremely high hardness caused by carbon enrichment, reaustenitization and formation of virgin martensite. As welded samples gave more favorable properties and microstructure than the post weld heat treated ones.

Correlation between Texture at Primary Recrystallized State and Magnetic Properties in Grain Oriented Electrical Steels

2011 ◽  
Vol 702-703 ◽  
pp. 726-729
Author(s):  
Jong Tae Park ◽  
Hyung Don Joo ◽  
Dae Hyun Song ◽  
Kyung Jun Ko ◽  
No Jin Park
Keyword(s):  
Magnetic Properties ◽  
Grain Boundary ◽  
Magnetic Flux ◽  
Grain Growth ◽  
Core Loss ◽  
Secondary Recrystallization ◽  
Magnetic Flux Density ◽  
Recrystallization Annealing ◽  
Goss Texture ◽  
Electrical Steels

Desirable magnetic properties for grain oriented electrical steels are low core loss and high magnetic flux density. These properties are closely related with sharpness of {110} texture. This Goss texture develops by abnormal grain growth during secondary recrystallization annealing. Based on experimental results, a general suggestion which estimates the magnetic properties after completion of secondary recrystallization from a primary recrystallized texture can be proposed. For a material to have better magnetic properties after completion of secondary recrystallization, it should have a primary recrystallized texture in which there are not only large number of ideal Goss grains, but also lower frequency of low angle grain boundary around those Goss grains.

Effect of Iron Oxide on the Structure, Electrical and Magnetic Properties of (70% mole V2O5- (15-x)% mole P2O5-15% mole B2O3) Semi Conducting Glass System

2007 ◽  
Vol 280-283 ◽  
pp. 327-332 ◽  
Author(s):  
E.E. Assem
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Iron Oxide ◽  
Treatment Time ◽  
Glass System ◽  
X Ray Diffraction ◽  
Electrical And Magnetic Properties ◽  
Heat Treated ◽  
Conductivity Increase ◽  
Before And After

A glass system according to the molar formula (70% mole V2O5- (15-x)% mole P2O5-15% mole B2O3), where x = 0, 1, 2.5, 5 and 7.5 % mole Fe2O3, was prepared by melting the pure powder chemicals at porcelain crucibles at 1000Co for three hours until the homogenous glass was obtained. The samples were quenched in air and heat-treated at 500 Co for 1, 2 and 3 h. The density, the molar volume, the electrical conductivity and magnetic properties were measured before and after the heat-treatment. The crystalline phases due to heat-treatment were determined using x-ray diffraction. The heat-treatment causes change of BO3 to BO4 and forming non-bridging oxygen. Replacing the phosphorus oxide with the iron oxide increases the magnetic properties while the conductivity increase up to 5% mole and then decreases. The changes of electrical and magnetic properties with heat-treatment time have a random behavior due to the change of the structure if the samples with heat treatment.

scholarly journals Effect Of Heat-Treatment On Microstructure And Magnetic Properties Of Nanocrystallized Mn-Zn Ferrite Powders

2015 ◽  
Vol 60 (2) ◽  
pp. 1347-1350
Author(s):  
W.H. Lee ◽  
C.S. Hong ◽  
S.Y. Chang
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Saturation Magnetization ◽  
High Energy ◽  
Treatment Temperature ◽  
Heat Treated ◽  
Zn Ferrite ◽  
Energy Ball ◽  
Size Of Particles ◽  
Increasing Temperature

Abstract The initial ferrite powders were subjected to high energy ball milling at 300rpm for 3h, and subsequently heat-treated at 573-1273K for 1h. Based on the observation of microstructure and measurement of magnetic properties, the heat-treatment effect was investigated. The size of initial powders was approximately 70μm. After milling, the powders with approximately 230nm in size were obtained, which were composed of the nano-sized particles of approximately 15nm in size. The milled powders became larger to approximately 550nm after heat-treatment at 973K. In addition, the size of particles increased to approximately 120nm with increasing temperature up to 973K. The coercivity of initial powders was almost unchanged after milling, whereas the saturation magnetization increased. As the heat-treatment temperature increased, the saturation magnetization gradually increased and the maximum coercivity was obtained at 773K.

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