共查询到20条相似文献,搜索用时 46 毫秒
1.
良好的补口是燃气管道防腐层质量的重要保障,目前城镇燃气管道3PE防腐层补口广泛应用热收缩带,根据施工现场工作经验,本文提出了热收缩带补口常见的三种失效方式,并通过故障树分析,对热收缩带补口失效原因进行有效分析研究,最后针对城镇燃气管道补口的现状,从三个方面提出预防和控制热收缩带补口失效的建议和对策。 相似文献
2.
聚乙烯外防腐层管线液体环氧补口技术首次在我国大型管线施工中试用时,通过现场指导试用过程与标准编制过程相结合的方式,提出了实际应用与这种补口技术的涂料供货和现场施工有关的技术标准,同时总结出补口技术具有以下特点:涂装过程简单、界面粘结牢固、修补容易、检验结果可靠、材料价格较低、能源消耗较少、流水作业较快、没有阴极保护电流屏蔽,为推广使用这种补口技术确立了初步的技术标准. 相似文献
3.
4.
5.
本文结合金虹航油管道工程,介绍了辐射交联聚乙烯热收缩套防腐补口施工工艺流程及搭接形式,分析了本工程管道焊缝处辐射交联聚乙烯热收缩套补口施工中遇到的问题、质量缺陷产生的原因并提出解决措施及优化对策,保证了钢制埋地管道的防腐层质量. 相似文献
6.
某油田在巡线过程中发现输油管道有泄漏现象,通过宏观分析、化学成分分析、金相检验和腐蚀产物分析等方法,结合服役工况,对输油管道腐蚀穿孔的原因进行了分析。结果表明:环焊缝防腐补口的密封失效而导致的外层腐蚀是输油管道腐蚀穿孔的主要原因,同时土壤中的Cl-加速了腐蚀穿孔的发生。 相似文献
7.
为解决三层聚乙烯热缩套(带)管道补口的质量问题,通过现场考察,总结出4类主要质量问题和4方面的现场条件问题,提出了与操作和检查有关的改进意见以及与套(带)选型选材有关的建议.结果表明,补口施工中的6个质量控制点是进行科学的质量检查和制定合理的质量标准;根据施工环境选择用套还是用带(定向钻工程中不应用带);套(带)收缩率不宜太高和收缩速度不宜太快;在保证底层质量的条件下允许有较小的空鼓或气泡;安装后边缘应有可见厚度的胶条;使用具有感温颜色显示功能的套(带),才能凭视觉控制最重要的温度指标. 相似文献
8.
9.
10.
11.
厚板铝合金搅拌摩擦焊匙孔补焊接头组织与性能 总被引:1,自引:0,他引:1
研究了35mm厚板铝合金搅拌摩擦焊匙孔补焊工艺,应用光学显微镜、扫描电镜、显微硬度仪及电子拉伸试验机等对接头的组织与性能进行了研究。结果表明,采用铝合金块材填充匙孔后进行FSW焊接,获得成型良好、表面光滑的焊缝;未加填充材料的匙孔位置,焊缝表面出现沟槽缺陷。FSW焊接一次接头的前进侧焊核区与热力影响区之间存在"吻接"缺陷;FSW焊接二次和三次接头的前进侧和后退侧过渡区均连接良好,二者组织无明显差别;FSW焊接一次和二次接头显微硬度分布呈W型,硬度最低值均出现在前进侧热影响区分别为56HV和60HV;采用搅拌头旋转速率为720r/min,焊接速率为180mm/min焊接工艺条件下,FSW焊接一次、二次和三次接头抗拉强度分别达到173、210和205MPa。 相似文献
12.
13.
14.
15.
David McLaurin David Marcum Mike Remotigue Eric Blades 《International journal for numerical methods in engineering》2013,93(3):266-275
Computational analysis and design has become a fundamental part of product research, development, and manufacturing in aerospace, automotive, and other industries. In general, the success of the specific application depends heavily on the accuracy and consistency of the computational model used. The aim of this work is to reduce the time needed to prepare geometry for volume grid generation. This will be accomplished by developing tools that semi‐automatically repair discrete data. Providing another level of automation to the process of repairing large, complex problems in discrete data will significantly accelerate the grid generation process. The developed algorithms are meant to offer a semi‐automated solution to a complicated geometrical problem — specifically discrete mesh intersection. The intersection‐repair strategy presented here focuses on repairing the intersection in‐place as opposed to rediscretizing the intersecting geometries. Combining robust, efficient methods of detecting intersections and then repairing intersecting geometries in‐place produces a significant improvement over techniques used in current literature. The result of this intersection process is a nonintersecting geometry that is free of duplicate and degenerate geometry. Results are presented showing the accuracy and consistency of the intersection repair tool. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
16.
17.
采用均苯四甲酸二酐(PMDA)为扩链剂,通过双螺杆挤出机将废旧高抗冲聚苯乙烯塑料(rHIPS)与PMDA进行熔融共混,成功实现了rHIPS的分子结构以及相界面的修复。研究了PMDA含量对rHIPS的相对分子质量、力学性能、动态力学性能、熔体流动性和断面形貌特征的影响。结果表明:PMDA与rHIPS发生了扩链反应,相对分子质量也得到了明显提升;当PMDA含量为0.9%(质量分数,下同)时,rHIPS/PMDA共混物的冲击强度达到10.8kJ/m2,提高了57%;随PMDA含量的增加熔融指数先减小后趋于平缓,储能模量和损耗模量升高,试样的冲断面形貌变得粗糙,相界面模糊。 相似文献
19.
20.
The aim of this work is to demonstrate the possibility of enriching NdBaCO superconducting powders by electromagnetic separation
(EMS) into fractions, which differ substantially in their physical, chemical and superconducting properties. Significant differences
in the properties of these fractions were seen. The concentrate fraction amounted to an average of 60–70% wt and was characterized
by better superconducting properties, while the tail properties were essentially lower, as required for preparation of superconductors.
The concentrate is actually an enriched superconducting powder with optimal quality and the tail is a recycle fraction needing
additional thermo-chemical treatment. In addition, the possibility of using EMS as an express method for evaluation of powder
quality and quick correction of synthesis parameters will be discussed.
相似文献