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 Posted: Mon 18:03, 10 Jan 2011 Post subject: air jordans Al intermetallic titanium casting new |
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Al intermetallic titanium casting new technology
And surface tension. Metallic temperature dependence of viscosity coefficient is: knock: AeE (4) where, for the viscous flow activation energy; A is a constant; R is the gas constant; T is absolute temperature; Diao for the viscosity coefficient. From (4) shows that the higher the temperature,[link widoczny dla zalogowanych], the lower melt viscosity, and surface tension also decreased with increasing temperature, so that atomization, the atomization air flow the energy required for breaking the metal melt is reduced, but when the temperature exceeds a certain value, the increase in the amount of fine powder small, the main reason may be due to the inevitable fog when in contact with air, with the temperature, the trend is to enhance the oxidation of the metal the resulting oxide inclusions in the melt, reducing the mobility of the metal, the viscosity will increase, when its role and reduce the temperature rise of the role of the metal offset melt viscosity, the higher the temperature at this time atomized powder particle size does not significantly increase the _6j. Surface tension on particle size and shape will have a major impact, the greater the surface tension of liquid metal harder broken, the more coarse powder obtained, it is easy to obtain spherical powder. Therefore, the surface tension of any of the factors that will be on the atomized powder particle size and shape affect the l_7j, a number of surface-active substances, such as O, N, S and so will reduce the surface tension, and have an average particle size is very fine powder, but powder relatively low rate of the ball. Temperature will also affect the surface tension, temperature, surface tension decreases. Considering, in order to obtain better powder particle size, spray pressure to choose 1.3MPa, temperature selection 1160oC molten metal, the best. Figures 3 and 4 at different temperatures and pressures of 1-I70 powder atomization SEM topography. 446 Figure 3 temperature l060oC, under the pressure of 0.7MPa atomized powder H70 Figure 4 SEM temperature 1160oC,[link widoczny dla zalogowanych], under the pressure of 1.3MPa. SEM atomized powder H70 Figure 3 Conclusions (1) the content of fine powder with liquid conductivity increases with decreasing tube diameter, but when the diameter is too small catheters, there will be gagging phenomenon, so the inner diameter of catheters general choice in 3.5nllll. (2) atomization pressure P is larger, the greater the melt rate, the smaller the particle size, but when the pressure P increases to a certain value, the rate will not increase, smaller powder size is no longer. P found in the test when more appropriate for the 1.3MPa. (3) the greater the melt temperature, melt viscosity and surface tension, d the smaller the particle size is smaller. Test at 1160 ℃ melt temperature more appropriate choice may be the ideal size of the powder obtained. References 1 Hu Zilong,[link widoczny dla zalogowanych], hydrogen storage materials, Beijing: Chemical Industry Press, 2002,2 Chenying Jun, Ji Xin Road. Theoretical Analysis of certain spray parameters. Powder Metallurgy Technology, 1995,13 (1): 23 ~ 253 Song Jide, Han Rentian. Spray atomization process factors on properties of alloy powder. Powder metallurgy industry, 1997,7 (2): 33 ~ 364 Zhang, Zhe-Wei Zhou. Spray forming mechanism of atomization in the spray, powder metallurgy technology, 1999,17 (3): 164 ~ 1655 Sun Jianfei, Cao Fuxiang. Spray forming process of the solidification behavior of atomized droplets. Special Casting & Nonferrous Alloys, 2002 (3): 1 ~ 36 Lv Haibo,[link widoczny dla zalogowanych], maternal front. Superheat of the melt on the atomization process. Central South University of Technology, 1997,28 (2) :149-1517 De Xie Zhuang, Shen Jun. Gas atomization characteristics of high silicon aluminum alloy powder morphology and size distribution. Special Casting & Nonferrous Alloys,[link widoczny dla zalogowanych], 2003 (1): 10 ~ 12 (Editor: Liu Wei)
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