Towards Developing HIC-Resistant X70 Pipeline Grade Steel for Sour Service Applications

这项建议涉及开发用于含硫服务石油/天然气应用的抗氢诱导开裂(HIC)钙处理X70管线钢级钢。除了更高的强度和韧性作为管线级钢的关键性能外，该行业还需要提高抗HIC性能，这是由于钢质管道对石油/天然气产品运输的持续需求，以及石油/天然气储量(供应)从“甜”变为“酸”(含硫化氢)的持续变化。HIC是一种脆性材料断裂模式，发生在低于屈服(永久变形)应力的应力下，并涉及作为必要事件的原子氢(H)的进入和相关的内部位置的陷阱。内部陷阱位置跨越许多长度尺度，从成分相边界(使用光学显微镜可以观察到)到纳米尺寸的强化金属间化合物颗粒(使用透射电子显微镜可以观察到)。单个氢陷阱位置将首先在空间上隔离，然后通过微悬臂梁的微机械测试(纳米压痕测量)将其与局部HIC敏感性联系起来，无论是否应用H充电前处理。从实践的角度来看，这项研究的价值在于以科学为基础构建了一个相对标度，对单个内部圈闭地点的HIC易感性进行排序。这样的排名对于确定更关键的内部陷阱地点至关重要，以便随后对旨在控制此类陷阱有害影响的工艺修改进行工程设计。这项研究的结果将对以下方面产生中长期影响：(I)为加拿大钢铁制造商开发含硫管道级钢产品；(Ii)新的和/或翻新的加拿大石油/天然气输送管道系统的运行可靠性、完整性和安全性。

This proposal addresses the development of hydrogen-induced cracking (HIC)-resistant Ca-treated X70 pipeline grade steel for sour service oil/gas applications. The industry's need for improved HIC-resistance, in addition to higher strength and toughness as key performance properties in pipeline grade steels, is driven by the continued demand for the transportation of oil/gas products by steel pipelines coupled with the ongoing change in the oil/gas reserves (supply) from "sweet" to "sour" (H2S-containing). HIC is a brittle material fracture mode that occurs at stresses below the yield (permanent deformation) stress and involves the ingress of atomic hydrogen (H) and associated trapping at internal sites as necessary events. Internal trap sites span many length scales, ranging from constituent phase boundaries (observable using light optical microscopy) down to nanometer-sized strengthening intermetallic particles (observable using transmission electron microscopy). Individual H trap sites will first be spatially isolated and then linked to local HIC susceptibility via micro-mechanical testing (nano-indentation measurements) of micro-cantilever beams, with and without a H charging pre-treatment applied. The value of the research from a practical perspective is a science-based construction of a relative scale ranking the HIC susceptibility of individual internal trap sites. Such a ranking is vital to identify the more critical internal trap sites for the subsequent engineering of process modifications designed to control the deleterious effect of such traps. The results of this research will have medium to long term impact on: (i) sour service pipeline grade steel product development for Canadian steelmakers and (ii) operating reliability, integrity and safety of new and/or refurbished Canadian oil/gas transmission pipeline systems.