共查询到20条相似文献,搜索用时 78 毫秒
1.
2.
日本东京煤气公司(Tokyo Gas)已收购巴西Nova Transportadora do Nordeste(NTN)和Nova Transportadora do Sudeste(NTS)两家公司15%的股份。NTN和NTS均系巴西国营石油公司(Petrobras)的子公司,在造价高达30亿美元的巴西Malhas32程中,分别承担两条天然气管道的修建任务。 相似文献
3.
4.
油田储罐溢流管道在实际运行和应用过程中具有尺寸大和缺少阀门的特点,应用气割开孔的方法存在较高的风险,但是如果应用传统的无齿锯切割方法的切割效率较低,而且会导致工期延长。因此本文针对油田储罐新旧溢流管道安全连头技术进行分析,应用多种方法和技术,实现多处溢流管道连头。经过相关研究和实践表明,在连头过程当中质量和效率越高,那么适用性和安全性越好,而且具有良好的发展前景。 相似文献
5.
海底天然气管道腐蚀与防护 总被引:2,自引:0,他引:2
海底管道的腐蚀是影响管道系统可靠性及其使用寿命的关键因素.对海底输气管道在海洋环境的腐蚀产生机理以及影响因素进行分析,介绍海底输气管道的腐蚀防护措施,对防腐涂层和阴极保护设计、使用以及目前腐蚀防护措施存在的问题进行探讨. 相似文献
6.
7.
8.
9.
介绍八钢蒙库选矿改扩建工程和该工程投产后遇到的主要生产工艺技术难题,为尽快顺产达标,蒙库选矿分厂采取的主要对策及主要技术改造。 相似文献
10.
11.
F. -Z. Li Z. -J. Liu Q. Jin Z. -M. Yu E. Liu 《Journal of Materials Engineering and Performance》1997,6(2):172-176
Work softening in aluminum and its alloys (Al-2Fe) was investigated at room temperature. Work softening was noticed in aluminum
with a purity of 99.996 %, in an Al-2Fe alloy with a purity of 99.996 % in the aluminum matrix, and in an Al-2Fe alloy with
a purity of 99.96% in the aluminum matrix, when the reduction in thickness of samples after rolling is more than 80 %, 60
%, and 90 %, respectively. Work softening was mainly related to the recovery at room temperature. The addition of iron to
aluminum purifies the aluminum matrix. The dispersed second phases formed by aluminum and iron may promote the recovery. 相似文献
12.
J. L. Mora‐Mendoza L. C. Saucedo‐Robles H. Rodríguez‐Clemente M. A. González‐Núñez G. Zavala‐Olivares M. J. Hernández‐Gayosso 《工业材料与腐蚀》2011,62(8):796-801
The objective of this study consisted in investigating the possible causes which give rise to the presence of low wall pipe thicknesses on a 16″ natural gas transport pipeline, even though during the last 12‐year period cathodic protection (CP) potentials were kept in the protection range at which external corrosion should not occur. Results from in‐line inspection from a 16″ natural gas transport pipeline showed 46 indications with more than 80% wall thickness lost due to external corrosion in the second segment of the pipeline. Direct inspection at the indication locations, review of the CP system performance, pipeline maintenance programs and studies, allowed to make an integral diagnostic where it was found out that the main cause of external corrosion was an inappropriate coating application since the pipeline construction, this situation has originated the increase of CP shielding effects through time. 相似文献
13.
通过对"工程造价管理"和"项目前期工作"的含义的界定,阐述了项目的正确决策,是加强项目前期工程造价管理的关键,同时,重点论述了加强项目前期工程造价管理所采取的主要措施。 相似文献
14.
15.
16.
采用功平衡法求解管材挤压变形力的对比研究 总被引:1,自引:0,他引:1
挤压是制备低塑性难变形金属和合金管材的一种精密成形方法,挤压力是选择挤压设备和校核挤压机部件强度的依据;合理地制定生产工艺规程和设计工模具等需要准确的计算挤压力,因此,求解计算精度高的挤压力计算公式在实际生产中显得尤为重要.本文在球坐标和柱坐标系下,采用功平衡法推导了锥模管材挤压变形力的两种理论计算公式;经生产中反复实验验证,两公式的计算结果都比较接近实测值,平均相对误差分别为6.6%左右、9.6%左右;而相关教材所给主应力法求解的管材挤压变形力公式计算结果的平均相对误差为15%左右.这表明本文推导的理论计算公式具有一定的工程实用性. 相似文献
17.
主应力法和功平衡法求解管材挤压变形力的再探讨 总被引:3,自引:1,他引:2
在极坐标系下建立了管材挤压变形力的计算模型,采用主应力法和功平衡法推导了管材挤压变形力的理论计算公式;经生产中反复实验验证,管材挤压变形力的理论计算结果接近实测值,主应力法计算结果的相对误差平均值为11.56%左右,功平衡法计算结果的相对误差平均值为-1.94%左右;而相关文献所给出的主应力法和功平衡法求解的管材挤压变形力公式计算结果的相对误差平均值分别为15%左右和6.6%左右。这表明,本文推导的理论计算公式计算精度高,具有一定的工程实用性。 相似文献
18.
通过对工程项目管理实践、存在的具体问题及解决途径的分析,提出采用三分法进行项目管理的思想.三分法就是按照三权分立的思想,从项目管理的实际需求出发,将项目管理中复杂的管理环节、管理对象、管理结构进行分解.使其互相制约、互相监督、互相促进,共同完成项目管理的任务. 相似文献
19.
V. P. Astakhov M. O. M. Osman M. T. Hayajneh 《International Journal of Machine Tools and Manufacture》2001,41(3)
This paper re-evaluates the known velocity relationships expressed in the form of a velocity diagram in orthogonal metal cutting, arguing that the metal cutting process be considered as cyclic and consisting of three distinctive stages. The velocity diagrams for the second and third stages of a chip-formation cycle are discussed. The fundamentals of the mechanics of orthogonal cutting, which are the upper-bound theorem applied to orthogonal cutting and the real virtual work equation, are re-evaluated using the proposed velocity diagram and corrected relationships are proposed. To prove the theoretical results, the equation for displacements in the deformation zone is derived using the proposed velocity relationships. To prove that the displacements in the deformation zone follow the derived equation and that this zone consists of two unequal parts, a metallographical study of chip structures has been carried out. To estimate the variation of stress and strain in the deformation zone quantitatively, a microhardness scanning test was conducted.Because it is proved that the chip formation process is cyclic, its frequency is studied. It is shown that when the noise due to various inaccuracies in the machining system is eliminated from the system response and thus from the measuring signal, and when this signal is then properly processed, the amplitude of the peak at the frequency of chip formation is the largest in the corresponding autospectra. 相似文献