Page 385 - Challenges in Corrosion Costs Causes Consequences and Control(2015)

CORROSION DAMAGE, DEFECTS, AND FAILURES 363

Figure 5.50 Visible crack on the exterior surface (19).

Figure 5.51 Internal surface of pipe with thick black deposit (19).

Internal examination of pipe sections showed thick black adherent scale (Fig. 5.51).
Green deposits were also present (Fig. 5.52).
Some areas in the pipe showed the presence of both green deposits and shiny
copper (Fig. 5.53). Pits were present in areas where copper is surrounded by green
deposits (Fig. 5.54). The green deposits indicate significant corrosion. The black scale
was carefully removed to identify the morphology of the pits (Fig. 5.55). The pits
were located at the bottom of a hole. The morphology of the pits appeared to be
characteristic of microbiologically influenced corrosion (Fig. 5.56).