Effect of the low temperature annealing on primary and secondary structures and magnetic properties of Fe-3% Si (original) (raw)
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Journal of Magnetism and Magnetic Materials, 2015
The effect of the initial annealing on structure evolution and magnetic properties during the final annealing of a 3.4% Si non-oriented grain steel was evaluated. Half of the samples were submitted to initial annealing at 1030°C before cold rolling and all samples were subjected to final annealing process at temperatures from 540°C to 1100°C. The magnetic induction and core loss in the final samples, the microstructure by optical microscopy and the crystallographic texture by X-ray diffraction and EBSD were evaluated. The results show that the samples without initial annealing presented better magnetic properties than the samples with initial annealing, due to the higher ratio between Eta fiber and Gamma fiber volume fractions (Eta/Gamma ratio) in their structure after final annealing.
Czechoslovak Journal of Physics, 2002
The one-stage cold rolled Fe-3%Si grain oriented elcctrote~hnical steel was used as experimental material. The inv~tigated steel was treated according 6 high temperature annealing (HTA) schedules with different heating rate and annealing atmosphere. The isothermal annealing at elevated temperatures in different atmospheres were carried out also. The analysis of relations between regime of HTA, features of inhibition particles system and microstructure and texture development during HTA was carried out.
IEEE Transactions on Magnetics
The simultaneous effects of the hot band grain size and cold reduction on the final grain structure, texture and magnetic properties of 3% Si steel were studied by variation of finishing temperature and hot band thickness during hot rolling, followed by cold rolling to final thickness and annealing in H2/N2 atmosphere. The results have shown that there is an optimum combination of hot band thickness and hot band grain size for maximum Eta/Gamma ratio and better magnetic properties (B50 and W1.5/60) after final annealing. For the thicker hot band, it was observed that higher finishing temperature, or larger hot band grain size, was necessary to achieve high Eta/Gamma and better magnetic properties. Too large hot band grain size, however, could result in smaller final grain size due to the intense nucleation on recrystallization in the shear bands and consequently poor core loss values. This behavior was explained based on the hot band grain structure and cold rolling effects on the t...
REM - International Engineering Journal, 2018
Lab experiments were carried out to check the effect of some process parameters of nitriding, performed simultaneously with decarburization, on magnetic properties of 3%Si Grain-oriented silicon steel produced by a low slab reheating technology. The samples of (GO) 3% Si steel collected as 0.27mm cold-rolled were submitted to a continuous annealing process at two temperatures, 860 and 900°C; three annealing times, 63.6, 95.4, and 119.25s; and three ammonia flows 0.1, 0.2, and 0.4Nm 3 /h. The nitrogen content obtained after the treatments was much higher than those obtained by the currently used process, and it increased as the ammonia flow rates and soaking times were increased, hindering the primary grain growth that adversely affected the magnetic properties. The increase of annealing temperature improved the decarburization and the magnetic properties. The best magnetic properties were found in the sample with the highest primary grain size and the lowest amount of absorbed nitrogen. The success of this practice, in terms of magnetic properties, was pointed out to be based on a drastic reduction on strip nitrogen increase.
Journal of Magnetism and Magnetic Materials, 2003
Hot rolled low Si (silicon) non-grain oriented electrical steel was cold rolled to different reductions. Cold rolled material was subsequently recrystallized, 650 C and 2 h, and then temper rolled (to 7% reduction) for the final grain growth annealing and decarburization treatment at 850 C for 2-24 h. The development of texture, grain size and magnetic properties were characterized at different stages of processing. Effect of texture on magnetic properties (watt loss and permeability) was observed to be best represented by the ratio of volume fractions of ð1 1 1Þ/uvwS=ð0 0 1Þ/uvwS fibers, as estimated by convoluting X-ray ODFs (orientation distribution functions) with respective model functions. Such a ratio was termed as generalized texture factor (tf) for the non-grain oriented electrical steel. An effort was made to delink effects of grain size and texture, as represented by respective tf, on watt loss and permeability by careful analysis of experimental data. In general, low tf and/or high grain size were responsible for low watt loss and high permeability. However, individual effect of grain size or tf on magnetic properties was less significant at low tf or large grain size, respectively. An attempt was made to fit regression equations, namely-linear, exponential and power, relating magnetic properties with tf and grain size, limiting the fitting parameters to 3. Least standard deviations, between experimental and predicted values, were obtained by power regression equations for both magnetic properties. r
Materialia, 2023
Fe-3.8wt%Si transformer steels were processed using two different additive manufacturing (AM) techniques, laser powder bed fusion (LPBF) and directed energy deposition (DED). While the LPBF processed samples exhibited a strong <001> orientation of the BCC grains along the build axis, the DED processed samples exhibited a randomized texture along the build axis. DED processed samples showed substantially coarser columnar grains as compared to their LPBF counterparts. The columnar grains exhibited a substantial number of low-angle sub-grain boundaries. All samples exhibited very good soft magnetic properties, with saturation magnetization (M s) values ranging from 205-232 emu/gm, and coercivity (H c) values ranging from 1.2-4.2 Oe. The Coercivity (H c) values were significantly lower when the magnetic field was applied parallel to the build axis, as compared to being perpendicular, which can be rationalized based on the columnar nature of the grains, resulting in a higher number density of grain boundaries in case of the field applied perpendicular to the build axis.
This paper presents a classic process-structure-properties approach for optimizing the magnetic properties of electrical steels. Cold-rolled non-oriented electrical steel (Fe; 0.001 wt% C; 0.2 wt.% Mn; 1.3 wt% Si) was subjected to extremely short 3-30 seconds annealing cycles in a range from 880°C to 980°C with a heating rate varying from 15°C to 300°C/sec. The resulting microstructure was studied by means of optical microscopy and X-ray orientation distribution function analysis. Recrystallized grains were refined with increased heating rate, caused by the nucleation rate increase, which is faster than the growth rate due to rapid heating. The optimal grain size of 60 to 80 mm in terms of magnetic properties was obtained by increasing the annealing temperature range to 920°C to 940°C with a higher heating rate of 300°C/sec and an annealing time of 6 to 9 seconds. With the heating rate increase, the characteristic {111} recrystallization fiber of cold-rolled steel was depressed, but the beneficial {110}<001> Goss texture component was significantly strengthened. The recrystallized grain size and texture were enhanced by rapid annealing, and, as a result, the magnetic properties of non-oriented electrical steel improved.
Journal of Magnetism and Magnetic Materials, 2014
The effect of rolling and annealing on the crystallographic texture and the magnetic properties of Fe-2.6% Si non-oriented electric steel during 90% cold rolling and different annealing temperature at (600 1C, 700 1C, 900 1C and 1100 1C) for 60 min and 20 min was analyzed. The 97% hot rolled as received material shows development of alpha and gamma fiber texture affecting on the magnetic properties at rolling and transverse direction. 90% cold rolling with moderate annealing temperature (up to 700 1C) and 60 min annealing time leads to better textures and improved magnetic properties. Due to coarse grained microstructure after annealing, neutron diffractions is an efficient tool for the analysis of Bulk texture of polycrystalline materials, well known for sufficient grain statistics and bulk texture measurement.