Cast Iron

Cast iron is about 3 to 5 times stronger in compression than in tension (Around 560 N/square mm and 140 N/square mm respectively). Compared to steel, cast iron melts at lower temperatures. Since cast iron is corrosion resistant, it is used extensively in rainwater pipes, flush water cisterns etc. Malleable cast iron is used for the manufacture of rails. The process is called malleable cast iron process. Here a portion of the carbon is extracted from the original cast iron. This makes it less brittle. Spheroidal graphite iron which is less brittle is produced by the introduction of flaky graphite in cast iron. Here freedom for the manufacture of large articles is an added advantage.