Engineering Properties of Low Coefficient Austenitic Ductile Iron for Engine Applications

Automobile and truck exhaust manifolds and turbocharger housings require a complex combination of properties and producibility. Type D-5S, austenitic ductile iron, containing 36%Ni, 5.1%Si, and 2.0%Cr, combines excellent high temperature properties with excellent castability and machinability. Information on the composition, and the mechanical and physical properties of the alloy are summarized. Effect of section size on mechanical properties; effect of composition on coefficient of thermal expansion and oxidation resistance; effect of heat treatment on machinability, oxidation resistance, and dimensional stability; and the effect of intermediate temperatures on mechanical properties and microstructure are described.