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

本提案旨在开发用于含硫油气应用的抗氢致开裂（HIC）钙处理X70管线级钢。除了作为管线级钢的关键性能特性的更高强度和韧性之外，该行业对改进的耐腐蚀性的需求是由对通过钢管输送石油/天然气产品的持续需求以及石油/天然气储量（供应）从“低硫”到“高硫”（含H2S）的持续变化所驱动的。HIC是脆性材料断裂模式，其在低于屈服（永久变形）应力的应力下发生，并且涉及原子氢（H）的进入和作为必要事件的内部位点处的相关捕获。内部陷阱网站跨越许多长度尺度，从成分相边界（使用光学显微镜观察）到纳米级的强化金属间化合物颗粒（使用透射电子显微镜观察）。个别H陷阱网站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），有和没有H充电预处理应用链接到本地HIC敏感性。从实用的角度来看，该研究的价值是一个基于科学的相对规模排名的HIC易感性的个别内部陷阱网站的建设。这样的排名是至关重要的，以确定更关键的内部陷阱网站的后续工程设计的过程修改，以控制这种陷阱的有害影响。本研究的结果将对以下方面产生中长期影响：（i）加拿大钢铁制造商的酸性服务管道级钢产品开发;（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.