Structural instability of the ferritic corrosion-resistant steel typically results in the carbides precipitation on the coarsened grain boundaries and in the associated intercrystalline corrosion. The examined steel revealed a tendency towards a defective fracture behaviour associated with the different carbide phase distribution. In the case of a preferential distribution within the grain interior, the relaxation processes along the welding line are limited and the transgranular cleavage fracture mechanism plays a role. Intergranular distribution of secondary phases brought tendency towards intergranular decohesion.