The tube spread around strong cooling technology is new technology of the making semisolid slurry and semisolid billet in Semi-Solid Processing. The technologic parameter of its on the A356 Alloy is researched in the ...
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ISBN:
(纸本)9780878492039
The tube spread around strong cooling technology is new technology of the making semisolid slurry and semisolid billet in Semi-Solid Processing. The technologic parameter of its on the A356 Alloy is researched in the article. It is showed by the result of the experimentation: that the fine and form verge on rotundity crystal grain is made at 180L/h and at 640-650 degrees C. It has met all the conditions in the semi-solid processing on semisolid billet. Semi-solid forming technology has been called the "new metal processing technology in the 21st century", which in foreign countries has certain industrial applications. In 1996 in the United States the sales of semi-solid casting was up to 1 billion dollars. But the industrial application in China is almost empty, one of the most important reasons is: the preparation of slurry or billet is too complicated or cost of production is too high, so that semi-solid forming technology in China has suffered serious setbacks on the road of industrialization. According to this situation, we have done a little attempts on manufacturing slurry and billet of semi-solid forming and have developed a new technology of spread around strong cooling whose intellectual property rights belong to us, equipment production is simple and the process is easy to control and the semi-solid slurry is east to prepare continuously. It will be discussed in this paper that process parameters of the single-tube strong cooling impacts on the microstructure of semi-solid
In the process of intensified sintering of iron powders under the action of an electric field with low voltage and high current, the effect of sintering temperature and sintering time on the densification process were...
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In the process of intensified sintering of iron powders under the action of an electric field with low voltage and high current, the effect of sintering temperature and sintering time on the densification process were investigated by means of thermal simulation. Both the metalloscope results and the statistic analysis of the distribution of pores in sintered compacts show that an electric field is not only providing the joule heat for a compact, but also accelerating the diffusion among iron atoms in the sintering process, which leads to intensified sintering. The relative density of the sintered compact can be over 95% at relatively low sintering temperature (800 degrees C) or within relatively short sintering time (2 min) at high temperature. Both sintering temperature and sintering time have effect on the process of iron powder densification. In this study, a sintering temperature of 1100 degrees C and a sintering time of 4 min lead to over 97% consolidation for iron powder compact. (C) 2008 Elsevier B.V. All rights reserved.
Sleeve structure is used to joint component parts of aerocraft or other product design and manufacture. It is an incompletely rigid joint. The contact stiffness of sleeve structure is non-linear and it must be taken i...
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ISBN:
(纸本)9780878492800
Sleeve structure is used to joint component parts of aerocraft or other product design and manufacture. It is an incompletely rigid joint. The contact stiffness of sleeve structure is non-linear and it must be taken into account for static or dynamic analysis. The assembling technology of sleeve structure is influenceable on the natural attributes of the structure. In this paper, nonlinear finite element method with the gap element of MSN/NASTRAN is combined with hammering test to simulate the nonlinear contact problem of sleeve structure design and manufacture. A novel method is used to define the close stiffness of gap element. Effect of assembling technologic parameters on inherent characteristic of sleeve structure are studied, such as diameter, quantity, arrangement mode of joint bolts and the prestressing force on bolts. Processes of sleeve structure assembling are proposed through theoretically analysis and simulating calculation.
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