Papers by Keyword: Strip Cast

Abstract: In this work, the influence of milling medium was investigated in order to achieve high energy-product Nd-Fe-B magnets, mostly by the remanence improvement related to the obtention of monocrystalline particles during milling. Nd-Fe-B alloy made by strip-casting process were used as starting material, which exhibits refined grain structure and demands special attention during milling in relation to coarse-grained, conventionally cast alloys. It was found that by using liquid medium during ball milling process, the mean particle size decreased, as well as the size distribution, which improved the particle alignment and hence the remanence in the sintered magnet. Texture was quantified by magnetic characterization based on reference isotropic magnets made in same conditions, and microstructure development was evaluated by optical microscopy. Moreover, after post-sintering treatment, the coercivity increased 20% compared to as sintered state without changing the remanence, providing an anisotropic magnet with high coercivity.

Abstract: FeSiAl magnetic powder contains high cost-performance as inductance components, which is widely used in various fields. In the present investigation the structure, magnetic properties and properties of magnetic powder cores prepared by strip cast ingot process were studied, and then compared with FeSiAl magnetic powder prepared by ingot cast broken process. The results show that strip cast sheet contained much little grain which surround with big grain, while the ingot cast broken has big grain connect with each other. For FeSiAl magnetic powder prepared by strip cast ingot process, the bigger grains were strip, the smaller grains were irregular shape, the surface of the powder was coarse, the powder prepared by strip cast ingot process was good for keeping the insulation film perfectly. For FeSiAl magnetic powder prepared by ingot cast broken, much of the powder was irregular bulk shape, and the grain corner was sharp, which is not good for insulation coating. Compared the patterns of strip cast ingot powder with the patterns of ingot cast broken powder, the diffraction peak of the patterns of strip cast ingot process powder became broaden. The initial magnetization curves of FeSiAl were obtained by vibrating sample magnetometer (VSM), observing that the saturation magnetization of strip cast magnetic powder was greater than that of ingot cast broken.

Abstract: Based on the classical cast theory and modern hot continuous rolling theory, in order to improve further the thickness precision of casting and control quality, so the dynamic mathematical model of strip-cast Looper system was established, which is nonlinear, strong coupling and uncertainty. According to the actual data, the comparative complete transfer function of Looper system is calculated. And the QDRNN-PID control strategy is put forward to subtract the coupling effect of Looper system. The simulation results prove that this control strategy can obtain a better control effect of Looper system after decoupling.

Abstract: The disadvantages of the conventional twin-roll caster for aluminum alloy are low casting speeds and limited choices of alloys that are castable by this processing. It is known that strip casting of aluminum alloy 5182 is very difficult because of their wider freezing zones. The vertical-type high-speed twin-roll caster used in the present study was devised to overcome these disadvantages. Features of the high speed twin roll casters are as below. Mild steel rolls were used in order to increase the casting speed and to be made at a lower equipment cost. Roll coating is produced in casting of Al-Mg alloy. Therefore lubricant, that resists heat transfer, was not used in the present study. Heat transfer between melt and the roll was improved by hydrostatic pressure of the melt. Low superheat casting was carried out in order to improve microstructure of the strip. In the present study, effectiveness of a high-speed twin roll caster for recycling aluminum alloy was investigated. The effects of the high-speed twin roll caster on alleviating the deterioration of mechanical properties by impurities were investigated. Properties of the cast strip were investigated by metalography, a tension test, and a deep drawing test.