Superior austempered ductile iron (ADI) properties achieved by prior hot isostatic pressing (HIP)

Book · Tue Dec 31 04:00:00 EST 1996

OSTI ID:442823

LaGoy, J L; Widmer, R; Zick, D H ^[1]

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1. Industrial Materials Technology Inc., Andover, MA (United States)

Ductile iron obtained from different foundries and cast by dissimilar methods has been successfully hot isostatically pressed (HIPed) before austempering to achieve substantially higher ductilities, without significant detriment to other properties, than those reached by austempering along. HIP was attempted to solve different mechanical deficiencies in austempered ductile iron (ADI) such as the lack of ductility in higher strength grades, inconsistent mechanical properties, and service life limitations. A variety of HIP temperatures were analyzed from near the austenitizing region up to within 56 C (100 F) of the melting point of ductile iron. Microporosity was eliminated by HIP at all temperatures, and subsequent austempering revealed a uniform ADI microstructure. HIP proved successful with both unencapsulated castings and those enclosed within steel canisters. Additional benefits caused by HIP processing of ductile iron castings without the austempering treatment include a significant decrease in mechanical property data scatter, high hardness at reasonable ductility levels, and a substantially reduced scrap rate.

• OSTI ID: 442823
• Report Number(s): CONF-960515--; ISBN 0-87170-568-0
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AUSTENITE
CAST IRON
EVALUATION
EXPERIMENTAL DATA
FERRITE
FRACTOGRAPHY
HOT PRESSING
INDUSTRIAL RADIOGRAPHY
MECHANICAL PROPERTIES
METALLOGRAPHY
MICROSTRUCTURE
POROSITY
TEMPERING
TENSILE PROPERTIES