The changes introduced in the microstructure of microalloyed pipeline steels by arc welding, caused more difficulties in the prediction of crack propagation. In the present work, we analyzed pipeline steel welding perpendicular to the rolling direction, using a single-V joint design with a 60-deg angle, under sulfide stress corrosion cmcking conditions. The heat affected zones (HAZ) were confined in compact tension samples. Tests were carried out in synthetic sea-water saturated with hydrogen sulfide, using the potential drop technique to measure the crack propagation. The results show that, in the mode 1, the crack growth occurs along the grain boundaries. The microstructure, which was parlially recrystallized, shows that the crack propagation is produced by hydrogen embrittlement. However, the cracks observed in the weld metal are transgranular.
Key Words: Sulfide stress corrosion. Heat affected zones. Welding. Microiillo yed steels.