Ductile Iron—Our Most Versatile Ferrous Casting Material
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Published:1969
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Since the discovery of ductile iron two decades ago, this versatile material has shown a truly phenomenal growth. The ductile iron family of materials combines the processing advantages of cast iron, that is, low melting point, good fluidity and castability, excellent machinability, and good wear resistance, with the engineering advantages of steel, including high strength, toughness, ductility, hot workability, and hardenability. Both chemical composition and heat treatment affect the matrix structure and the graphite formation, which must be spheroidal in shape. Rigid production controls are employed to produce reliable ductile iron castings. A wide range of tensile strength, yield strength, and elongation is produced from a single chemical composition through heat treatment. ASTM specifications for the ductile iron family list grades of 120-90-02, 100-70-03, 80-55-06,65-45-12, and 60-40-18. Attention is now being given to alloying elements and special chemical composition to broaden the range of physical properties of ductile iron. Successful applications of the various grades of ductile iron, including alloy grades, are found in the automotive industry, steel mills, farm equipment, machine tools, pipe lines, road building equipment, and many other manufacturing industries.