Further SEM and EDX analyses were performed on polished cross sections of samples previously prepared from the top and bottom surface of the pipe. Fig. 5a shows one area on the bottom inner surface of the pipe with cap of mound of corrosion product (iron oxide) covering the pit. Also, as confirmed by the EDX analysis, high concentrations of chloride ions were accumulated inside the pit, A2 location in Fig. 5a. SEM micrograph and the EDX results for the pit on the top inner surface of the pipe was shown in Fig. 5b, the result shows mainly iron oxides as corrosion product.