Evaluation of the in-service weldability of vintage and modern pipeline steels

保持石油和天然气管道网络的完整性对加拿大能源运输系统至关重要。这在很大程度上取决于焊接许多老化的管道钢的能力，这些管道钢可能已经服役50多年了。然而，在这段时间里，炼钢实践发生了变化，焊接工艺也发生了变化，焊接工艺倾向于更高的焊接速度和冷却速度，以更快地制造和降低成本。目前的提案将建立滑铁卢大学和斯坦特咨询有限公司之间的关系。目标是开发加工实践，并确定X70等老式管道钢的可焊性极限。由于在焊接过程中有必要避免过度的冷却速度，以免导致硬相的形成，因此了解哪些焊接参数将产生具有良好完整性和高韧性的焊接组织至关重要。这将通过为老式和现代X70管道钢开发连续冷却转变图来确定。热循环将使用最先进的Gleeble热机械测试系统应用于钢，以模拟各种焊接热循环和冷却条件，并将这些与硬度和韧性相关联。这将为限制焊接参数在现场的应用提供关键见解，以确保售后维修的完整性。

Maintaining the integrity of the oil and gas pipeline network is essential to the energy transport system inCanada. Much of this depends on the ability to weld many of the aging pipeline steels, which may be well over50 years in service. However, over this time steel making practices have changed, along with the weldingprocesses which have tended to favour higher welding speeds and cooling rates for more rapid fabrication andlower costs. The current proposal will build a relationship between the University of Waterloo and StantecConsulting Ltd. The goal will be to develop processing practices and identify the weldability limits for vintagepipeline steels such as X70. Since it is necessary to avoid excessive cooling rates during welding which maylead to formation of hard phases, it is vital to understand what welding parameters will produce weldmicrostructures with good integrity and high toughness. This will be determined by developing continuouscooling transformation diagrams for both vintage and modern X70 pipeline steels. Thermal cycling will beapplied to the steels using a state-of-the-art Gleeble thermo-mechanical testing system to simulate variouswelding thermal cycles and cooling conditions, and correlate these with hardness and toughness. This willprovide key insights in what limiting welding parameters for can be applied in the field to ensure integrity afterin-service repair.