The role of steel chemistry on the microstructure/properties in the heat affected zone for high strength linepipe

运输能源（天然气和液体）的管道是北美能源格局不可或缺的一部分。仅加拿大就拥有超过 75,000 公里的天然气管道和 25,000 公里的液体（例如成品油和沥青）管道。此外，还有修建新管道的建议，例如横加管道公司的 Energy East 项目，将石油产品从艾伯塔省输送到加拿大东海岸的炼油厂（4,500 公里，每天 110 万桶石油）。这一广泛管网的安全、经济建设和运营对加拿大具有战略意义。 存在使用较大直径的管道和/或增加管道的操作压力以提高系统的吞吐量的趋势。这导致使用更高强度的管线钢等级以避免使用更厚壁的管线钢。目前的技术水平使用 X70 或 X80 钢种（屈服应力分别为 490 和 560 MPa）。使用更高强度的钢材意味着需要更少的材料，从而降低材料和运输成本。这些材料面临的工程挑战之一是开发稳健的制造和现场连接工艺，即环焊缝。该项目涉及与所用钢材的机械性能相关的方面，特别是焊接对一系列不同钢化学成分的这些性能的影响。目前，钢的评估遵循基于性能的规范，例如屈服应力，即没有明确考虑钢的成分。 该行业面临两个基本挑战。对于像 Evraz 这样的钢铁生产商来说，挑战与化学优化有关（特别是适当添加 Cr、Mo 和 Nb 的合金）。另一方面，TCPL 等管道建设者/运营商必须了解不同钢材对管道建设过程中焊接产生的热量输入有何反应。该项目的成果将是：i) 增加热影响区微观结构/机械性能的知识基础，以实现先进技术，ii) 将这些知识传授给我们的行业合作伙伴，以及 iii) 培养 5 名高素质人员（3 名博士，2 份 PDF）

Pipelines to transport energy (natural gas and liquids) are an integral part of the North American energy landscape. Canada alone has more than 75,000 km of natural gas and 25,000 km of liquids (e.g. refined oil and bitumen) pipelines. Further, there are proposals to construct new pipelines such as TransCanada Pipeline's Energy East project to deliver oil products from Alberta to refineries on Canada's east coast (4,500 km 1.1 million barrels of oil per day). The safe and economic construction and operation of this extensive pipeline network is of strategic importance to Canada. There is a trend towards using pipelines of larger diameter and/or increasing the operation pressure of the pipeline to improve the throughput of the system. This leads to using higher strength linepipe steel grades to avoid using thicker wall linepipe steel. The current state of the art uses X70 or X80 steel grades (yield stress of 490 and 560 MPa, respectively). Using higher strength steels translates into less material being required thereby lowering material and transportation cost. One of the engineering challenges for these materials is the development of robust manufacturing and in field joining processes, i.e. girth welds. This project addresses aspects related to the mechanical behavior of the steels used and, in particular, the effects of welding on these properties for a range of different steel chemistries. Currently, the evaluation of steels follows performance based specifications such as the yield stress, i.e. the composition of the steel is not explicitly considered. There are two fundamental challenges that face the industry. For steel producers such as Evraz, the challenge relates to chemistry optimization (in particular, the appropriate alloy additions of Cr, Mo and Nb). On the other hand, pipeline constructors/operators such as TCPL have to understand how the different steels will respond to the heat input from welding during the construction of the pipeline. The results from this project will be i) an increased knowledge base for the microstructure/mechanical properties in the heat affected zone for advanced, ii) transfer of this knowledge to our industry partners and iii) the education of 5 high qualified personal (3 Ph.D., 2 PDFs)