Corrosion resistance of ductile iron pipes

Corrosion resistance of ductile iron pipes

♦The corrosion protection property

The cast iron has perfect anti-corrosion property, according to the record, there were cast iron pipelines layed over 300 years ago still in use, and countless cases show that cast iron pipes have more than 100 years of service life. As regard to the using of ductile iron pipes, the history is over 30 years. But ductile cast iron is nearly identical to gray cast iron in chemical composition. It also contains far more silicon, carbon and other elements than steel. The resistance of ductile cast iron to corrosion is also similar to that of gray cast iron. This has been demonstrated in use and proved empirically.

♦Corrosion protection of pipeline

It is true that the underground ductile iron pipeline transferring potable water and gas will be greatly influenced by the chemical and physical property of the soil directly. The most important factor that result to corrosion is when pipes are jointed to be a long and continuous electrify entity. In other words, the soil corrosion will show different features on the different pipelines. Based on this difference, it forms concentration cell. Partial cell possibility of the concentration cell will be very strong. If laying a electrify entity in the soil will bring long line of electric current and then the current anode will form very aboil corrosion. The welded steel pipeline is an obvious example. Ductile iron pipe, owning to it’s mechanical or T type joint and sealed by insulating rubber gasket, there is an insulation joint every 4-6 meters.

♦Resistance to corrosion caused by electric current

Since ductile iron has relatively high electric resistance, it is resistance to corrosion caused by electric current.