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

该提案旨在开发用于含硫油气应用的抗氢致开裂（HIC）的经ca处理的X70管道级钢。除了管道级钢的关键性能更高的强度和韧性外，行业还需要提高抗高压性能，这是由于钢铁管道运输石油/天然气产品的持续需求，以及石油/天然气储量（供应）从“甜”到“酸”（含硫化氢）的不断变化。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，涉及原子氢(H)的进入和必要的内部俘获。内部陷阱位置跨越许多长度尺度，从组成相边界（使用光学显微镜观察到）到纳米级强化金属间颗粒（使用透射电子显微镜观察到）。单独的氢阱位置将首先在空间上被隔离，然后通过微悬臂梁的微机械测试（纳米压痕测量）与当地的氢离子敏感性联系起来，有或没有进行氢电荷预处理。从实践角度来看，该研究的价值在于基于科学的构建一个相对尺度，对单个内部陷阱位点的HIC易感性进行排名。这样的排名对于确定更关键的内部陷阱位置是至关重要的，这对于随后的工艺修改工程设计来控制这些陷阱的有害影响是至关重要的。这项研究的结果将对以下方面产生中长期影响：(1)为加拿大钢铁制造商开发酸性服务管道级钢材产品；(2)新建和/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.