Corrosion kinetics of pipeline carbon steel weld immersed in aqueous solution containing H2S

One important challenge in the petroleum industry is reduce the problem produced by the corrosion of structures or pipeline steel caused by contact with the aggressive fluids, such as aqueous solution containing H2S or CO2. In this work, the corrosion of weldment of API X52 pipeline steel immersed in NACE solution saturated with H2S was studied. In the corrosion tests, the electrochemical techniques, polarisation curves and linear polarisation resistance were carried out in samples of API X52 pipeline steel focus in the three different zones of the weldment: heat affected zone, weld bead and base metal. In addition, a superficial analysis was made in order to identify the film of corrosion products. The temperature increment and the H2S dissolved in the NACE solution increase the corrosion rate of the three different zones. The heat affected zone was the more affected by the corrosion test and the phases mackinawite, troilite and pirrothite were identified in the film of corrosion products.