Chemically, ductile iron is similar to grey iron, with some minor but important exceptions. By treating the molten base metal with magnesium, the excess carbon that comes out of solution during solidification can be forced into a spheroidal shape. This spheroidal formation of graphite is what gives ductile iron it's unique mechanical properties.
Smith Foundry produces ductile iron in accordance with American Society of Testing and Materials (ASTM) A536. ASTM A536 covers a general class of ductile irons not specific to any application.
Grades of ASTM A536 Ductile Iron Produced at Smith Foundry
|ASTM A536 Grade (SAE)||Tensile Strength||Yield Strengths||Elongation||Brinell Hardness|
|60-40-18 (D4018)||60,000 p.s.i.||40,000 p.s.i.||18 %||187 Max|
|65-45-12 (D4512)||65,000 p.s.i||45,000 p.s.i||12 %||156-217|
|80-55-06 (D5506)||80,000 p.s.i.||55,000 p.s.i.||6 %||187-255|
|100-70-03 (D7003)||100,000 p.s.i||70,000 p.s.i.||3 %||241-302|
*Tensile, Yield and Elongation values are minimums required by ASTM A536 for an independantly cast tensile test bar sample. Consult ASTM A536 or Smith Foundry for more information.
|Desirable properties||Common Applications|
|Strength comparable to some steels||Shaft and drive components|
|Toughness||Lift arms and linkages|
|Low cost alternative to steel castings and fabrications||Brackets|
|Discs and digger teeth|