Grey cast iron pipes

Pipes of unalloyed cast iron have been used for more than 100 years for long-distance and distribution lines. By the end of the fifties, grey cast iron was used exclusively for these pipes, and since that time has been replaced by ductile cast iron. 

Mruk and Palermo and Hunt, W. J., The Design of Grey and Ductile Cast Iron Pipe, Cast Iron Pipe News, March/Apiil 1970. 

There is no limit to the size of grey-iron castings. Although not a corrosion-resistant material, grey iron does have a useful resistance to chemicals, water, gas and steam, and for this reason is used for valves, pipes and fittings with these substances. 

---