 Wysłany: Pon 0:33, 20 Gru 2010 Temat postu: ugg prezzo Nuclear Power Electric wedge gate valve |
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Brittle material. (3) by scanning electron microscopy and transmission electron microscopy of the fracture analysis, fracture characteristics and river pattern and cleavage fracture of the existence of secondary cracks (transgranular distribution), that suffered the fracture of large one-time stress, crack for rapid transgranular expansion, makes the material showing the characteristics of brittle fracture. (4) the determination of that body R, R angle is small, only 0.08 ~ O. 1mm, 0.5mm and drawings several times the required value, R angle smaller,ugg prezzo, more obvious effects of the gap material, the stress lines at the distribution more closely in the foot, high-pressure valve in the load more easily formed by the stress concentration. According to the provisions of the measured R-R than the small number of drawings, so when the R parts of the body in the compression stress on several times larger than the normal position, it is very easy to create materials in the R part of the local yield deformation and formation of crack source, and crack under stress in this large and rapid expansion for the instability, causing the valve to an instant burst. (5) the general body the mechanical properties of materials,air jordans, the results show that, 0.5mm notched specimen elongation of the plasticity index and the average lower than the smooth specimens of about 459,5; 1.0mm elongation of notched specimen plasticity lower than the average of about 89 smooth specimens,ed hardy clothing, indicating strong materials on the notch sensitivity, stress concentration is very obvious. Another impact of the average temperature of materials only 5J, and fast-cooling solution by heat treatment after tempering the impact of its room temperature value can be doubled, so the body long after repeated high-temperature tempering of cold does cause slow precipitation of carbides,ugg milano, tendency to increase the brittleness. (6) Body Blow stress estimates: when the valve burst pressure is 6700N/cm2, pressure vessels according to the U.S. Commission recommended method of assessment oCC operator, P = aF (1 a B - 2), s a 80mm (valve wall thickness), BBDB a 395mm (body diameter), F-1.064 (based on calculation), a 192MPa (obtained from the above equation.) (7) simplify the mechanical analysis of body into a damaged, set a half of the container aperture, b for the cutting depth of processing, when the stress intensity factor of 360 *: K1 A {1 A \)) stare, /-a +-b7c Ⅱ T (, if a one 195mm, b-lmm, you have to K1-2180N ・ mrn a /. If the 6-2mm was obtained when K1-1698N ・ mm. the material CTOD test drawn A 0.06mm, according Ki a Eay &, K1 obtained a 2100N ・ mm / 2. by the J-test materials and from the results of K} a rF, K1 obtained a 1500N ・ mm-a / 2 is smaller, so valve is bound to burst. from the above analysis shows that, assuming that depth of cut b-lmm be K1-218ON ・ mm_I., and the CTOD was a 2100N ・ iTlrn K1; by J1 K1 experiment showed a 1500N ・ mm-3 / 2 smaller, so the damage is bound to happen. 4 Conclusion of the examination and analysis of the above come, nuclear electric blasting wedge gate valve body wall is due to processing of R is small, making the body cavity in the 6700N ・ em. under the action of the R sites have a high degree of stress concentration and crack formation in this condition, the source. force Ⅱ of the body material of the improper tempering heat treatment, resulting in increased brittleness; therefore body condition in high pressure, the crack transgranular failure for the rapid expansion, causing the valve to produce at the moment when the blast pressure test. Note: According to Qiao Mao, Liu Guocheng, Du Zhan-Jun, Zhu Dong exploration, the district took part in some trials. References: [13 Liao Qingguang. ZG20CrV the failure of the main steam pipe and restoration of body heat [13. Chinese Mechanical Engineering Society of the second national conference proceedings Mechanical Equipment Failure Analysis [c]. Shanghai: Physical Testing Institute, 430. [23 Zhou Shunsheng. steel brittle and engineering structure of brittle fracture [M3. Shanghai: Shanghai Science and Technology Press, 1983. [33 Shen Fu Huang. On the large-scale heat treatment of cast-off pieces of [J3. metal heat treatment, 1982,6. [43 Electrical Engineering Handbook Editorial Board. Mechanical Engineering Handbook [M]. Beijing: Mechanical Industry Press,air jordan shoes cheap, 1982. [53 Yin double increase. fracture damage theory and its application [M]. Beijing: Tsinghua University Press, 1992. [63 Pan Zhen editor. Pressure Vessel Materials Practical Guide [M3. Beijing: Chemical Industry Press, 2000.7. [73 Shanghai Jiaotong University \ 相关的主题文章： air jordan shoes cheap LiBr solution h-ξ expansio ugg prezzo TBS sealed in the petrochemical industr ugg boots günstig Thermodynamic Properties of HFC-227ea calculated _3141 |
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