Wisconsin Alumni Research Foundation

Materials & Chemicals
Materials Chemicals
Method and Additive for Improving the Properties of Thin-Wall Castings
WARF: P02357US

Inventors: Carl Loper, Simon Lekakh

The Wisconsin Alumni Research Foundation (WARF) is seeking commercial partners interested in developing an additive that increases the toughness of thin-wall CGI and DI castings.
Ductile iron (DI) and compacted graphite iron (CGI) exhibit excellent castability, allowing the production of thin-wall castings. However, rapid cooling during solidification of these thin-wall castings usually results in adverse effects on their mechanical properties (e.g., hardness, ductility and toughness) and machinability.
The Invention
UW-Madison researchers have developed an additive that increases the toughness of thin-wall CGI and DI castings. The additive includes a non-ferrous metal oxide that has less affinity for oxygen than iron, and a metal sulfide that has less affinity for sulfur than magnesium. Because the metals contained in the oxides and sulfides are not alkali, alkali earth or rare earth metals, the incidence of defects in the castings is also reduced.

When added to a cast iron melt, the metal oxide and metal sulfide react with magnesium to form nucleation sites composed of a core of magnesium oxide surrounded by magnesium sulfide. These nucleation sites cause increased nucleation of graphite so that the cross-section of the thin-wall iron casting is more uniform. This, in turn, decreases the amount of carbide formed in the casting, and increases the casting’s toughness.
  • Production of effective thin-wall CGI and DI castings with acceptable mechanical properties
Key Benefits
  • Improves machinability of thin-wall castings by completely avoiding the formation of cementite
  • Provides energy savings because additive-containing castings require little or no additional modification prior to use
  • Increases nodule count and produces a more uniform distribution of graphite nodules, resulting in improved mechanical properties
  • May improve feed metal efficiency of castings
For current licensing status, please contact Emily Bauer at [javascript protected email address] or 608-960-9842