ASTM A439 / A439M

This specification covers austenitic ductile iron castings, which are used primarily for their resistance to heat, corrosion, and wear, and for other special purposes. Austenitic ductile iron, also known as austenitic nodular iron or austenitic spheroidal iron, is characterized by having its graphite substantially in a spheroidal form and substantially free of flake graphite. It contains some carbides and sufficient alloy content to produce an austenitic structure.

Chemical Properties

Type Carbon, max Silicon Manganese Phosphorus, max Nickel Chromium
Note A: Additions of 0.7 to 1.0 % of molybdenum will increase the mechanical properties above 800°F (425°C).
Note B: Not intentionally added.

Mechanical Properties

Type Tensile strength,
ksi [MPa]
Yield strength,
min, ksi [MPa]
Elongation in 2 in.
[50 mm], min, %A
Brinell hardness (3000 kg)