TCPL - Hot Tap Connections II

管道的热接连接使新管道能够连接到运行中的管道，而无需关闭运行中的管道。由于一条管道可能耗资数亿美元或更多，避免因关闭而造成的收入损失对TcCPL来说是很有价值的。尽管已有将小直径管道连接到大直径管道的技术，但这项研究将开发最先进的计算机模型来优化这项技术，评估其设计的健壮性，或将该技术扩展到连接几乎相同直径的管道。焊接是一个非常复杂的过程，涉及在大约1 cm^3的焊接熔池中在大约1秒的时间内完成从熔化到凝固和成形成品的整个材料加工过程。低合金钢的对流系数和气体温度控制着低合金钢焊缝和焊接热影响区组织的冷却速度。对流系数控制着从管道外壁的焊缝流出的热量。这一点在碳含量较高、铁素体-珠光体组织较高的老钢管钢中尤为重要。焊接缺陷，如气孔和裂纹可能很重要。优化工艺的设计和控制以生产最佳的焊缝是一个重要的挑战。优化管道设计，包括热水龙头连接，包括热水龙头的设计和制造，也是一个同样重要的挑战。

Hot tap connections of pipelines enable a new pipeline to be connected to an operating pipelinewithout shutting down the operating pipeline. Since a pipeline can cost hundreds of millions of dollars or more,avoiding the lost income that would be incurred by a shut down is valuable to TcCPL. Although the technologydo this for connecting smaller diameter pipes to larger diameter pipes exists, this research will develop state ofthe art computer models to optimize this technology, to assess the robustness of their designs or to extend thistechnology to connect pipes of nearly equal diameter.Welding is a very complex process that involves the complete material processing from melting tosolidification and shaping the finished product in a weld pool of roughly 1 cm^3 in times of roughly 1 second.The microstructure controls the weld properties. The convection coefficient that controls the flow heat throughthe pipe wall from the weld on the external wall of the pipe and the gas temperature control the cooling rate ofthe weld and weld heat-affected zone microstructure in low-alloy steels. This is particularly important in olderpipe steels that have higher carbon levels and ferrite-pearalite microstructure. Weld defects such as porosityand cracks can be important. Optimizing the design and control of the process to produce the best welds is animportant challenge. Optimizing the design of a pipe line, including hot tap connections including the designand fabrication of the hot tap is an equally important challenge.