The ductile iron pipe  (its superior characteristics and practicability) 

 -  1984 
 - 8 p.  ill.  30 cm 
<br/><br/> It is proved that gray cast iron has high resistance to corrosion and is moulded easily, but it lacks i strenght. Steel, on the other hand, is strong but its resistance to corrosion is not enough. So, it had been a long-cherised hope that there would be another material possessing both the advantages of gray cast iron and steel, until the year of 1949 when discovered the method to make the graphite in the cast iron spheroidal by adding magnesium to the molten iron. 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Cast-iron pipe<br/>Water-pipe