共查询到20条相似文献,搜索用时 109 毫秒
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化工设备标准椭圆封头简便作图法与最佳参数选择陆博福(黑龙江黑化集团有限公司压力容器厂)宋学成(齐齐哈尔市劳动局锅炉检验所)关键词化工设备压力容器椭圆封头简便作图参数选择在化工设备压力容器制造中,对于椭圆封头制造加工以及封头样板检具制作,均要绘制椭圆... 相似文献
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杨晓丹 《中国石油和化工标准与质量》2012,32(5):123
设备制造中成型的作业很多,如筒体、锥形封头、弯管、弯制法兰、衬圈等零件都需要进行弯曲,球形封头、椭圆封头、碟形封头以及膨胀节、螺旋面等需要冲压或旋压。 相似文献
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通过比较几种旋压封头与标准椭圆封头的形状,并在理解JB4732[1]、ASME[2]、AD[3]等规范关于凸形封头的设计计算方法的基础上,认为只要能满足GB150-1998[5]规定的标准椭圆封头的允许形状偏差,不论封头的成形方法如何,都应属于标准椭圆封头,故在材料、厚度相同时可以等效代替标准椭圆封头. 相似文献
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在压力容器制造中,采用JB/T4729-94《旋压封头》中的椭圆形封头来替代JB/T4737-95中的标准椭圆形封头,笔者认为,这种替代不是等效的,因而也是不妥当的。该文用薄膜理论分析了不等效的原因,旋压椭圆形封头的本质及其应力分布,指出了它与标准椭圆封头的替代关系。 相似文献
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通过比较几种旋压封头与标准椭圆封头的形状,并在理解JB4732[1]、ASME[2]、AD[3]等规范关于凸形封头的设计计算方法的基础上,认为只要能满足GB150-1998[5]规定的标准椭圆封头的允许形状偏差,不论封头的成形方法如何,都应属于标准椭圆封头,故在材料、厚度相同时可以等效代替标准椭圆封头。 相似文献
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标准椭圆封头选用的探讨 总被引:1,自引:0,他引:1
应用薄膜理论应力分析,指出用JB/T4729-94中的椭圆封头替代JB/T4737-95中的椭圆封头是不妥的,并对制造过程中由于拉伸减薄而使用较厚钢板来制造封头时应注意的问题进行了论述。 相似文献
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利用先进的数值计算方法,实现封头冲压成形过程从定性分析向定量控制的转变成为目前研究热点问题之一.然而在有限元数值计算模型中,如何精确读取成品封头壁厚减薄量一直是难点.为此,首先基于一般通用有限元软件建立了一个标准椭圆形封头冲压成形数值计算模型,然后结合大型工程计算与优化软件开发相应用户子程序,实现封头成品各点壁厚值的精确提取,并对封头坯料结构几何参数进行了优化,得到最佳的坯料壁厚值和直径,研究结果可为封头成型制造过程定量控制提供技术支持. 相似文献
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苯乙烯是重要的石油化工原料。本文介绍了国内外苯乙烯生产的发展概况,合成乙苯,苯乙烯所用的催化剂种类,并就苯乙烯生产及催化剂的发展趋势提出了自己的观点。 相似文献
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Synthesis and characterization of homopolymers and copolymers of various acrylates and acrylonitrile
Various homopolymers and copolymers of methyl acrylate, ethyl acrylate, butyl acrylate, and acrylonitrile in different feed ratios were synthesized. These were characterized by IR, 13C-NMR, DSC, DTA, and TGA. Spectroscopic characterization helped in differentiating copolymers of different mol ratios. Thermal analysis revealed different degradation patterns for homopolymers and copolymers. The temperature and energy changes associated with various phase transitions were dependent on the chemical composition of homo- and copolymers, as expected. © 1993 John Wiley & Sons, Inc. 相似文献
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The variation of the Au 4f binding energy of Au clusters with the cluster size has been established by measuring the binding energies of clusters whose size distributions were independently determined by HREM and STM. The binding energy increases significantly when the cluster size is less than 2 nm. Au-Cu bimetallic clusters of the composition Cu3Au have been deposited for the first time on carbon substrates. The shifts in the core level binding energies of the bimetallic clusters show the effect of alloying in the case of large clusters, but show effects of both alloying and cluster size in the case of the small clusters. The interaction of CO with Cu3Au clusters is stronger than with a bulk Cu metal. The interaction of CO with small Cu clusters also seems to be stronger than with bulk Cu or with large Cu clusters. 相似文献
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《国际聚合物材料杂志》2012,61(1-4):113-122
Abstract Kinetics and mechanisms of oxidation of 6 acetals by molecular oxygen and ozone in liquid phase have been studied. Reaction with molecular oxygen (70°C, 15–16 hr) leads to the formation monoethers of the corresponding glycols with 68–90% selectivity. Salts of metals and complexes with crown-ethers have increased the reaction rate significally. Ozone have reacted with acetals with formation similar products. The mechanisms of intermediate stages have been proposed. 相似文献
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G. R. Hamed 《The Journal of Adhesion》1983,16(1):31-39
A substantially greater detachment energy is required to strip a polyethylene tereph-thalate (Mylar) film from a styrene-butadiene-styrene (SBS) triblock copolymer compared to that for peeling from a random styrene-butadiene (SBR) copolymer. This is true even though the intrinsic interaction between the Mylar and each elastomer is expected to be similar because of their virtually identical chemical composition. It is proposed that this difference in peel strength (between the SBS and SBR) is a consequence of the much higher dissipative capacity of the former elastomer. Another manifestation of this is the higher cohesive tear strength of the SBS compared to the SBR. Extents of energy dissipation within each elastomer during detachment of the Mylar adherend are consistent with the hypothesis that the average maximum stress experience before detachment is some similar fraction of each elastomer's tensile strength. 相似文献
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Polypentafluorostyrene (PPFS), polymethylacrylate (PMA), and poly(pentafluorostyrene-co-methylacrylate), poly(PFS-co-MA) were prepared and the wetting characteristics of polymer blends of PPFS and PMA were compared with that of poly(PFS-co-MA) via contact angle measurements. The critical surface tension of polypentafluorostyrene was found to be 22.6 dyne/cm, which is comparable to the value reported for polytrifluoroethylene (22 dyne/cm). The critical surface tension of poly(PFS-co-MA) is not linearly related to its composition. The polymer blends of PPFS and PMA exhibit significant surface enrichment of the fluoropolymer. The harmonic-mean method1 was employed to determine surface tensions of these polymers and many known polymers. It is found that the method produces useful surface tension data provided the contact angle values are derived from testing liquids of dissimilar polarity. 相似文献
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