Various approaches to different demands of low alloy steels with specified HIC resistance

HIC (Hydrogen Induced Cracking) has become a major concern in the transportation as well as processing of H{sub 2}S containing media. This has led to specific requirements to the steel concerning the resistance against HIC. The steel behavior is strongly correlated with its microstructural features. To cover the different aspects of application for HIC resistant steels in linepipes or pressure vessels three different production routes are considered in this paper. These are TMCP (Thermo-Mechanical Control Process), N (normalizing) and Q and T (quenching plus tempering). The steelmaking process steps are similar, the main differences are in the steel composition and in the plate manufacturing steps. The different production steps, analysis concepts, the involved metallurgical mechanisms and the benefits of each process are pointed out.