Review of current developments on high strength pipeline steels for HIC inducing service

Nowadays, an increasing number of oil and gas transmission pipes are constructed with high-strength low alloy steels (HSLA; nonetheless, many of these pipelines suffer from different types of hydrogen damage, including hydrogen-induced cracking (HIC). Many studies are being done to investigate the role of key metallurgical and processing factors to limit the negative effects of HIC in HSLA steel pipes. The thermomechanical control process (TMCP) is a microstructural control technique that avoids the conventional heat treatment after hot rolling and attempts to obtain the desired mechanical properties during the forming process. Recent research has shown that TMCP provides high HIC resistance without adding high amounts of alloying elements or applying expensive heat treatments. However, there is an incipient knowledge on predicting HIC behavior, both in susceptibility and kinetics, in HSLA steel pipe when it is exposed to hydrogen charging service conditions. This paper presents a review of the current developments of HSLA and TMCP of pipeline steels, as well as the phenomenological and empirical models proposed to predict the kinetics of HIC as a function of key parameters such as heat treatments and microstructures, especially nature and spatial distribution of non-metallic inclusions and the hydrogen permeation rate and the mechanical and fracture mechanics properties.