Ductile Iron Pipes

Ductile Iron Pipes Ductile Iron pipes are pipes made of ductile iron. They are commonly used for potable water distribution and the pumping of slurries, sewage and process chemicals. Ductile iron is a spheroidized graphite cast iron. Ductile iron pipes are a direct development of earlier cast iron pipes which it has now almost replaced. The high level of dependability on ductile iron pipes is due to its various superior properties and it is a most sought after pipe for many applications. History of ductile iron pipes American Cast Iron Pipe Company pioneered the development of ductile iron pipes and produced experimental casts of these pipes as early as in 1948. The first shipment was made in 1955. Since then production of ductile iron pipes has grown steadily and it is now a predominant piping material for conveying water and other liquids. Ductile iron As the name suggest, it is a cast iron having the property of ductility. This quality of cast iron long sought after by metallurgists, was realized in 1948. Ductile iron is acclaimed as one of the most significant developments of the century and has had an increasing impact on the industry. Besides the property of ductility, ductile iron has, in addition, strength and impact resistance much greater than that of gray iron.  Ductile iron also retains the corrosion resistance property of gray iron hence it is an ideal material for pipes. Ductile iron is produced by treating molten low sulphur base iron with magnesium under closely controlled conditions. The startling change in the metal is characterized by the free graphite in ductile iron being deposited in spheroidal or nodular form instead flake form as  gray cast iron. With the free graphite in nodular form, the continuity of the metal matrix...

Cast Iron

                         Cast Iron The term “Cast iron” identifies a large family of ferrous alloys. These are primarily iron alloys which contain 2% or more carbon and from 1% to 3% silicon. The properties of cast iron can be varied widely by varying the percentages of carbon and silicon, by alloying with various metallic elements, and by varying the practices of melting, casting, and heat treatment. Cast iron in its basic form is a brittle material which has a very little impact strength. It has a little or practically no toughness when compared to low carbon steels.  It has a fraction of the tensile strength of low carbon steels.  When a cast iron piece fails it will not deform in a noticeable way and appears to snap apart or break in a manner consistent with a snap.  There is no early warning of a failure. The graphite phase is pure carbon and acts as a natural defect in the material.  The iron is so saturated with carbon that graphite forms (free carbon) and causes the cast iron to be weaker.  Much smaller amounts of carbon is combined with iron (Fe) in the form of iron carbide (Cementite) which is hard and brittle. Cast irons can be classified as either unalloyed cast irons or alloy cast irons. Unalloyed cast irons are essentially iron-carbon-silicon alloys containing small amounts of manganese, phosphorus, and sulfur. There are other specialty cast irons like austenite gray cast iron and inoculated cast irons.  Cast iron can be alloyed as in carbon steels with elements like Chromium (Cr) and Nickel (Ni) etc. There are basically five types of cast irons. These are gray, ductile, malleable, compacted graphite, and white iron. Except in the case of white cast iron, all other cast irons have...