Understand the large difference in properties among coiled tubing steels having similar microstructures via electron work function analysis

Abstract Coiled tubing (CT) steel is widely used in the oil and gas industry. It is worth noting that CT steels of different grades show similar microstructures but their mechanical and tribological properties can be quite differently. The underlying mechanism is unclear, making it difficult to further tailor the CT steel with clear guidelines for specific applications. Using electron work function (EWF) as a probing parameter, we analyzed several typical CT steels having very similar microstructures but large difference in their hardness and wear resistance. The EWF analysis indicates that minor elements in the steels may play an important role in strengthening local atomic bonding, leading to considerable variations in properties of the CT steel. This study also shows that EWF is a promising indicator, providing supplementary information to help understanding material behavior and identify crucial factors for material design or tailoring, which the conventional techniques may not be able to achieve.