A 200 mm (8 in.) diameter gray iron pipe that
failed because of graphitic corrosion. The pipe
was part of a subterranean fire control system. The
external surface of the pipe was covered with soil;
the internal surface was covered with water. Severe
graphitic corrosion occurred along the bottom external
surface where the pipe rested on the soil. The smalldiameter
piece in the foreground is a gray iron pump
impeller on which the impeller vanes have disintegrated
because of graphitic corrosion. Courtesy of Robert D.
Port. Permission granted by Nalco Chemical Company,
1987