A New Model For Hydrogen-Induced Crack (HIC) Growth in Metal Alloy Pipelines Under Extreme Pressure

Pipeline failure caused by Hydrogen-Induced Cracking (HIC), also known as Hydrogen Embrittlement (HE), is a pressing issue for the oil and natural gas industry. Bursts in pipelines are devastating and extremely costly. The explosive force of a bursting pipe can inflict fatal injuries to workers, while the combined loss of product and effort to repair are highly costly to producers. Further, pipeline failures due to HIC have a long lasting impact on the surrounding environment. Safe use and operation of such pipelines depend on a good understanding of the underlying forces that cause HIC. Specifically, a reliable way to predict the growth rate of hydrogen-induced cracks is needed to establish a safe duration of service for each length of pipeline. Pipes that have exceeded or are near the end of their service life can then be retired before the risk of HIC-related failures becomes too high. However, little is known about the mechanisms that drive HIC. To date, no model has been put forth that accurately predicts the growth rate of fractures due to HIC under extreme pressures, such as in the context of natural gas and petroleum pipelines. Herein, a mathematical model for the growth of fractures by HIC under extreme pressures is presented. This model is derived from first principles, and the results are compared with other models. The implications of these findings are discussed, and a description of future work based on these findings is presented.