MATERIAL TECHNOLOGIES, INC.
68 Ambassador Drive, Red Bank, NJ 07701
Phone: (732) 542-5800
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Material Technologies Incorporated Precision Materials

Publications: Austempering Selected P/M Alloys Synopsis

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Ausvac Process Increases Impact Values of Powder Metal Components to Double that of P/M Forged Components and Comparable to Wrought Steel

The Ausvac process is an austempering process using a vacuum furnace for ACTIVATED™ NANOTECH™ steel" providing double the impact properties of powder metal forgings and equal to or greater than impact properties of wrought low alloy steels.

The mechanical properties and product performance of full density ACTIVATED™ NANOTECH™ steels, also called (ANP™ steels), are readily altered by conventional treatment methods which are applicable to wrought product. Mechanical properties are changed by the alteration of metallurgical structures such as grain size adjustment and/or phase changes. An example of a change is shown in the attached table where ANP steels at 7.8 g/cc and 7.6 g/cc were sintered at a temperature of 2460 degrees F and subsequently hardened and tempered at various tempering temperatures (800, 1100 and 1300 F) resulting in a 100% martensitic structure of various tempers. Similarly, the same compositions and densities were sintered at 2460 F and subsequently austempered using an "Ausvac" *heat treating process. Ausvac is austempering in a vacuum furnace with a 10 bar quench processed resulting in a 100% bainitic structure formed at 750 F.

The Charpy impact values of unnotched and (notched) bars were found to increase significantly from 50 foot Ibs unnotched and 7 foot Ibs (notched) to 80 foot Ibs unnotched and 15 foot Ibs (notched) for 7.8 g/cc and from 55 foot lbs unnotched and 6 foot Ibs (notched) to more than 120 foot Ibs unnotched (the limit of the impact testing machine) and 10 foot Ibs (notched) for the 7.6 g/cc. test samples. These Charpy impact values are double that of P/M forged parts and are equal to or exceed those of wrought low alloy steel of equivalent hardness. These properties can be further enhanced by known metallurgical methods of producing finer grain steels.

Richard R. Phillips
September 25, 2004


* Developed jointly by Engineered Pressed Materials of St. Marys, PA and Solar Atmospheres of Hermitage, PA.
ACTIVATED, NANOTECH and ANP are trademarks of Material Technologies, Inc.
* patent pending