Microstructure engineering for high productivity welding of pipeline steels

目前有一些关于扩大北美石油和天然气管道系统的重要建议，包括麦肯齐河谷、阿拉斯加北坡和Keystone XL管道。这些项目将使用新的更高强度的钢(X80和X100)和新的焊接技术(串联和双火炬气体保护焊或激光混合焊接)，以降低建筑成本。对于这些管道系统的完整性来说，焊缝必须充分了解机械性能，这一点至关重要。由于低温和可能融化的大片永久冻土，北方管道面临着进一步的挑战。这些考虑导致了新的基于应变的设计性能标准。

There are currently a number of significant proposals for expansion of the North American oil and natural gas pipeline system including the Mackenzie Valley, the Alaska North Slope and Keystone XL pipelines. These projects will involve the use of new higher strength steels (X80 and X100) and new welding techniques (tandem and dual torch gas metal arc or laser hybrid) to lower construction costs. It is critical for the integrity of these pipeline systems that the welds have well understood mechanical behaviour. There are further challenges for northern pipelines due to the low temperatures and the probable melting of significant regions of permafrost. These considerations have led to new strain based design performance criteria.