High temperature wear and friction behaviour of 15Cr–15Ni–2Mo titanium-modified austenitic stainless steel in liquid sodium

The sliding friction and wear behaviour of 15Cr–15Ni–2Mo titanium-modified austenitic stainless steel (alloy D9) was studied in high purity liquid sodium at high temperature viz. 473 and 823 K respectively using a reciprocating-type tribometer. Weight loss measured in specimens after the tests was negligible. Scar depth measurements on disc specimens were carried out by confocal laser scanning microscope, which revealed not much number of scratches tested at 473 and 823 K, respectively. Scanning electron microscopy on worn pin specimens revealed the presence of deformed zone in the rubbed area, and adherence of wear particles at few locations in both the cases. Damage is more in specimens tested at 823 K because of the softening of the rubbing surfaces at that temperature. Further, friction coefficient is lower at 473 K than at 823 K.

Research highlights▶ Friction and wear studies of 20% cold-worked 15Cr-15Ni- 2Mo Titanium-modified austenitic stainless steel (alloy D9) in liquid sodium at high temperature. ▶ Low value of friction coefficients for this alloy is due to lubrication mechanism independent of oxygen content. ▶ Values well within the design criteria (as per fuel duct assembly for the Fast Flux Test Facility) for pads of wrapper material for FBRs.