Characterization of interface of Inconel 625-API X60 steel for corrosion

• Main Author: Moorthy, Jishnu Leon Jerome
• Other Authors: Dong Zhili
• Format: Final Year Project
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Engineering::Materials
• Online Access: https://hdl.handle.net/10356/166765
• Institution: Nanyang Technological University

Numerous countries have set a goal of achieving net zero emissions by 2050. As a result, it is possible to repurpose existing pipelines and containers for the transportation and storage of hydrogen. However, before they can be utilized under operational conditions, it is crucial to establish their safety in interaction with hydrogen. This research seeks to investigate how hydrogen embrittlement behavior of API X 60 steel, which is cladded with the corrosion-resistant alloy Inconel 625, is affected by straining. API X 60 with hot-rolled CRA is commonly used in long-distance transportation pipelines for oil and gas. However, during the repair and maintenance phase, these pipelines become vulnerable to damage that can result in strains beyond the plastic limit. To comprehend the mechanisms behind hydrogen embrittlement related to such events, it is essential to map the heterogeneities in strain, damage (crack/void), and their correlation to the underlying microstructures. In this research paper, dog bone samples of API X 60 with CRA are subjected to three different plastic strains (5%, 15%, and 25%) and then charged with hydrogen. After hydrogen charging, high-resolution Scanning Kelvin Probe Force Microscopy (SKPFM) is utilized to map the diffusion profiles of hydrogen at the sample's profile section. The outcomes of SKPFM, electron microscopy, and the variation in mechanical behavior before and after hydrogen emission reaction (HER) are presented as a function of pre-straining.