Cast-iron pipe

Figure 7.16 Carbon steel corroded by organic acid on a cast iron pipe elbow.

The occurrence of graphitic corrosion is not location specific, other than that it may occur wherever gray or nodular cast iron is exposed to sufficiently aggressive aqueous environments. This includes, and is common to, subterranean cast iron pipe, especially in moist soil (Case History 17.1). Cast iron pump impellers and casings are also frequent targets of graphitic corrosion (Case Histories 17.2 through 17.5). 

Sampie Specifications 10 in. (25 cm) outside diameter, gray cast iron pipe... 

Cast iron pipes - 100 mm internal diameier, 2.5 to 3 m long and 13 mm thick. (This is a cumbersome and costlier arrangement, is not often used)... 

With the fall of the Roman Empire, the ancient water supplies petered out. In early medieval times, people were content to conduct local water in wooden pipes to public cisterns. The first wooden pipelines for water were laid at Liibeck about 1293 and in 1365 at Nuremberg. In 1412 the Augsburg master builder Leopold Karg first used wrought-iron pipes in conjunction with wooden pipes to supply water. Because of their propensity to corrosion, they seem to have proved a failure and a few years later they were exchanged for wooden, lead, and cast-iron pipes. 

Cast-iron pipes were used for the mains in the early stages of town gas supply, their sockets being sealed with tarred rope, oakum, or lead. Originally the connection pipes were lead and later of galvanized or coal-tarred forged iron. After the defeat of Napoleon in 1815, there was a surplus of cheap musket barrels, and these... 

Cast iron piping materials shall not be used. 

Gusseisen, n. cast iron pig iron, -rohr, n., -rohre, f. cast-iron pipe, guss-eisem, a. cast-iron, -fahig, a. castable. 

Borehole waters are generally very hard and cast iron pipes are still used because of the low internal corrosion rates permitted by the scaling which occurs naturally. Acidic waters cause graphitic attack on cast irons. 

Local corrosion or pitting is more important for practical purposes than the rate of general corrosion, and may proceed 10 times or so more rapidly than this. Inasmuch as certain types of cast iron are liable to suffer graphitic corrosion, whereas steel does not, steel might theoretically be expected to show to some advantage when used for buried pipelines. In practice, however, a cast-iron pipe has to be of stouter wall than a steel pipe for equal strength, and it is doubtful whether any distinction between the rust resistance of the two materials in the soil is justified. 

Smith Harry, W., Cast Iron Pipe News, 38, 3, winter (1971)... 

An example where reactant concentration is solely governed by corrosion considerations is in the production of concentrated nitric acid by dehydration of weak nitric acid with concentrated sulphuric acid. The ratio of HN0j H2S04 acid feeds is determined by the need to keep the waste sulphuric acid at > 70 Vo at which concentrations it can be transported in cast-iron pipes and stored after cooling in carbon-steel tanks. 

Centrifugal force is used to introduce molten metal into a mold cavity that is spinning around its axis. Cast iron pipe is produced in centrifugal molds, and copper-base alloy bearings are also commonly produced this way. Permanent metal molds are usually coated or lined to extend operating life. 

B16.1 Cast Iron Pipe Flanges and Flanged Fittings... 

ANSI/ASME Cast iron pipe flanges 7005/2 2532 4504 NEE ... 

ASME B16.1, Cast iron pipe fianges and fianged fittings. 

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