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One Minute Mentor: Tensile properties of austempered ductile iron

Issued at 2019-01-28



t is obvious from the graph that austempered ductile iron (ADI) is a unique cast iron material with tensile properties attributable to γH with the fine dispersion of ferrite.

Austempering is accomplished by first heating the casting to a temperature in the austenite-phase range (usually 815 to 925°C, or 1500 to 1700°F). The next step is holding for the time required to saturate the austenite with carbon, then cooling to a temperature above the Ms temperature at a rate sufficient to avoid the formation of pearlite or other mixed structures. The final step is holding at that austempering temperature for the time required to produce the optimal structure of acicular ferrite and carbon-enriched austenite. In some instances, austenitizing is completed in an intercritical region.

 



Source: asminternational.org



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