Resumen del autor, extraído del trabajo. Underground pipeline steels are mainly low alloy steels of the API specifications (for instance, X65 and X52), showing a ferritic-pearlitic structure with elongated inclusions, mainly MnS. These materials have been proved susceptible to Transgranular Stress Corrosion Cracking (TGSCC) in diluted solutions of near neutral pH. This cracking phenomenon has been firstly studied by Parkins[1, 2], as a consequence of field observations [3]. Cracking was mainly observed under disbonded region of the pipeline coating, where cathodic protection is not effective. Hydrogen embrittlement due to the diffusion of atomic hydrogen produced in the cathodic reaction at the crack tip has been identified as the active cracking mechanism [4, 2]). Testing methodologies for Environmental Assisted Cracking (EAC) usually follow the procedures of fracture mechanics standards, operating under displacement or strain control [5]. To reproduce cracking morphology observed in field, tests under load control have been performed and compared with Slow Strain Rate tests under displacement control[6].