Study of solidification characteristics about energy-saving amorphous steel
Date Issued
2012
Date
2012
Author(s)
Lin, Yi-Ting
Abstract
In the previous studies, the manufactured of amorphous ribbons by planar flow casting, which is mainly analyzed by operating parameters based on fluid dynamics but is seldom studied in the effect of heat transfer. However, the effect of heat transfer is extremely important in the process of ribbon solidification, thus this study focuses on the operating parameters of heat transfer (wheel heat transfer coefficient, molten jet temperature) and researches the effect of amorphous ribbon solidification with different operating parameter by Ansys-Fluent. The casing material is , molten jet pressure is 41125 Pa and the speed of wheel is 20 m/s in this study. The wheel heat transfer coefficient is set from 120 to 1 and molten jet temperature is set from 1501 K to 1684 K.
From the simulated results of different wheel heat transfer coefficient, it is found that puddle length and cooling rate may affect thickness of ribbon. When the wheel heat transfer coefficient is set from 120 to 400 , the thickness of ribbon decreases from 39.8μm to 36.3μm; however, when the wheel heat transfer coefficient is set from 400 to 1000 , the thickness of ribbon increase from 36.3μm to 37.2μm. The cooling rate is no apparently different when wheel heat transfer coefficient lower than 400 , at this time the thickness of ribbon becomes thinner while the puddle length get shorter. When wheel heat transfer coefficient higher than 400 , puddle length has no significant influence on the thickness of ribbon, which gets thicker as cooling rate rises.
From the simulated results of different molten jet temperature, it is found that viscosity of fluid and cooling rate may affect thickness of ribbon. When molten jet temperature is set from 1501K to 1548K, the thickness of ribbon rises from 36.3μm to 36.6μm. The thickness of ribbon decreases from 36.3μm to 36.2μm when molten jet temperature is set from 1548K to 1683K. In addition, it is found that molten jet temperature causes more eddy currents in downstream of puddle, which leads the changing rate of thickness of ribbon increase.
From this study it can be summed up that the velocity field of puddle and the thickness of ribbon become stable when wheel heat transfer coefficient higher than 400 and molten jet temperature between 1500K and 1548K. This study could provide associated studies of planar flow casting as reference.
Subjects
amorphous
planar flow casting
wheel heat transfer coefficient
molten jet temperature
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-101-R99543034-1.pdf
Size
23.54 KB
Format
Adobe PDF
Checksum
(MD5):b4794ae586f7be81be60e0bd5b5cc753