Ion-nitriding of austenitic stainless steels

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:389754

Pacheco, O ^[1]; Hertz, D ^[2]; Lebrun, J P ^[3]; Michel, H ^[4]

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1. BW Fuel Co., Lynchburg, VA (United States)
2. Framatome-Nuclear Fuel, Lyon (France)
3. Nitruvid, Argenteuil (France)
4. EMN/LSGS, Nancy (France)

Although ion-nitriding is an extensively industrialized process enabling steel surfaces to be hardened by nitrogen diffusion, with a resulting increase in wear, seizure and fatigue resistance, its direct application to stainless steels, while enhancing their mechanical properties, also causes a marked degradation in their oxidation resistance. However, by adaption of the nitriding process, it is possible to maintain the improved wear resistant properties while retaining the oxidation resistance of the stainless steel. The controlled diffusion permits the growth of a nitrogen supersaturated austenite layer on parts made of stainless steel (AISI 304L and 316L) without chromium nitride precipitation. The diffusion layer remains stable during post heat treatments up to 650 F for 5,000 hrs and maintains a hardness of 900 HV. A very low and stable friction coefficient is achieved which provides good wear resistance against stainless steels under diverse conditions. Electrochemical and chemical tests in various media confirm the preservation of the stainless steel characteristics. An example of the application of this process is the treatment of Reactor Control Rod Cluster Assemblies (RCCAs) for Pressurized Water Nuclear Reactors.

• OSTI ID: 389754
• Report Number(s): CONF-951222--; ISBN 0-87170-561-3
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
36 MATERIALS SCIENCE
AUSTENITE
CONTROL ELEMENTS
CORROSION RESISTANCE
CRACKS
DEFORMATION
DIFFUSION
EXPERIMENTAL DATA
HARDNESS
ION BEAMS
LAYERS
MECHANICAL PROPERTIES
MICROSTRUCTURE
NITRIDATION
PLASMA
PWR TYPE REACTORS
STAINLESS STEEL-304L
STAINLESS STEEL-316L
WEAR RESISTANCE
X-RAY DIFFRACTION