Fabrication of Fe-6.5wt%Si Ribbons by Melt Spinning Method on Large Scale

Abstract:The flow behavior of . %Si alloys during hot compression was investigated at temperatures 650-950 • C and strain rates 0.01-10 s −1 . The results showed that the flow stress depended distinctly on the deformation temperatures and strain rates. The flow stress and work hardening rate increased with the decrease of temperature and the increase of strain rate. The activation energy under all the deformation conditions was calculated to be 410 kJ/mol. The constitutive equation with hyperbolic sine function and Zener-Hollomon parameter was developed. The peak stress, critical stress, and steady-state stress could be represented as σ = A + Bln(Z/A). Dynamic recrystallization occurred under the deformation conditions where the values of Z were lower than 10 20 . Processing maps were established to optimize the processing parameters. The power dissipation efficiency decreased in the high temperature and low strain rate region, increased in the high temperature and high strain rate region, and remained unchanged in other regions with the increase of true strain. Furthermore, the unstable area expanded. The true strain of 0.7 was the optimum reduction according to the processing map. Based on the analysis of surface quality, microstructures, and ordered structures, the optimized processing parameters for the Fe-6.5wt. %Si alloys were the temperature and strain rate of higher than 900 • C and 0.01-10 s −1 , respectively, or 800-900 • C and lower than 0.4 s −1 , respectively.

Section: Introductionmentioning

confidence: 99%

Flow Behavior Characteristics and Processing Map of Fe-6.5wt. %Si Alloys during Hot Compression

Wen

Han

Zhang

et al. 2018

“…Melt-spinning can be used for refining grains [5] and preparing magnetic material ribbons with good magnetic properties [6]. Previously, high-silicon steel ribbons of 25 mm in width were prepared by melt-spinning [7]. In this paper, various heat treatments were applied to the as-spun Fe-6.5 wt.…”

Section: Introductionmentioning

confidence: 99%

AC Iron Loss Prediction and Magnetic Properties of Fe-6.5 wt. % Si Ribbons Prepared by Melt-Spinning

Wang

Liang

Chen

et al. 2018

Ultra-thin Fe-6.5 wt. % Si ribbons of 35 µm in thickness were prepared by melt-spinning. The magnetic properties were investigated before and after annealing at 1000 • C. The DC properties and low-frequency (400 Hz~10 kHz) iron losses significantly improved after heat treatment. A simplified formula-P t = k t B N m -based on the Steinmetz law, which can be used to predict the AC iron loss, is presented. The symbols "k t " and "N" are defined as functions of microstructure and frequency. According to the tested results of iron loss, the values of "k t " and "N" can be fitted and therefore the simplified formula can be determined. The extent of AC iron losses can be predicted according to the formula. The results obtained from the formula predict AC iron loss to a good degree. The method developed in this work could be extended to other magnetic materials for predicting AC iron loss with greater ease.

“…However, it is very brittle at room temperature due to the formation of ordered structures, such as B2 (Pm 3 m) and DO 3 (Fm 3 m) phases [3,4]. Various techniques have been developed to produce plates avoiding the room-temperature embrittlement, such as chemical vapor deposition [5], hot dipping [6], spray forming [7][8][9], rapid solidification [10][11][12], and direct powder rolling [13]. Moreover, a hot-warm-cold rolling method, combined with proper heat treatment, has been reported to fabricate sheets with thicknesses of 0.03-0.05 mm [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Fabrication Technology and Material Characterization of Hot Rolled Cylindrical Fe-6.5 wt. % Si Bars

Wen

Xue

Han

et al. 2018

Cylindrical Fe-6.5 wt. % Si bars of 7.5 mm diameter were successfully fabricated from an as-cast ingot through three rolling stages, with 10 total passes: rough rolling at 850-900 • C and 8-10 m/min; medium rolling at 800-850 • C and 10-15 m/min; finish rolling at 800-850 • C and 12-18 m/min. The evolution of the microstructure, texture, and ordered structure were studied, and the mechanical properties were investigated. Results indicated that the grains were refined by the hot bar rolling. Area fractions of the {100}<011> and {011}<100> oriented grains decreased to 0 during hot bar rolling, whereas the {100}<001>, {011}<211>, and {112}<110> components increased. Furthermore, the γ fiber with {111}<110> component was dominant. After the hot bar rolling, the DO 3 ordered phase was suppressed, and the B2 ordered domains were refined. Ductility of the as-rolled bar was better than that of the rotary-swaged bar, due to the absence of the DO 3 ordered phase, and refinement of the grains in the rolled bar. Moreover, discontinuous dynamic recrystallization (DDRX) occurred at a high deformation rate during the rough rolling, and continuous dynamic recrystallization (CDRX) appeared at a low strain rate during the finish rolling. Hence, hot bar rolling technology is an excellent process for the fabrication of Fe-6.5 wt. % Si bars.