Ductile Iron Properties, Advantages, Costs, and
1. Ductile iron castings offer a wide
range of mechanical properties:
The ductile iron family offers the designer and engineer a unique
combination of strength, wear resistance, fatigue resistance, and
toughness, as well as excellent ductility characteristics.
The tensile strength of ductile iron begins where gray iron stops.
The as-cast tensile strength of ductile iron ranges from 60,000 to
The yield strength of A395 ductile iron is a minimum of 40,000 psi.
This is higher than grades 70-36 and 60-30 cast steel or ordinary
gray iron (which has no true yield strength)
Ductile iron is one of the most ductile of all cast irons and shows
18% to 30% elongation on a test piece.
2. Ductile iron castings are economical:
Ductile iron castings are a cost effective substitute for carbon and
low alloy steels, and in some applications, ductile iron can even
outperform steel. Ductile iron is less brittle than most types of
iron. Several grades can be used in the as-cast condition without
additional heat treatments. When heat treated ductile iron’s design
flexibility can be enhanced to an even greater degree.
3. Ductile iron castings outperform cast steels and gray iron in
The improved mechanical properties of ductile iron increase its
resistance to breakage from physical load, or mechanical and thermal
shock far above that of gray iron. Its wear resistance is comparable
to some of the best grades of steel and superior to gray iron in
heavy load or impact load situations. It is considerably less
expensive than cast steel and only moderately more expensive than
gray iron. Its high yield strength and ductility make it an
economical choice for many applications.
4. Ductile iron castings are readily available:
Unlike cast steel, ductile iron capacity in China is abundant. This
ensures the end user that production lead-times are reasonable and
that a variety of suppliers are capable of producing their product.