THE UNLUBRICATED RECIPROCATING SLIDING WEAR OF 316 STAINLESS-STEEL IN CO2 AT 20-DEGREES-C-600-DEGREES-C

The frication and wear behavior of 316 stainless steel in CO//2 has been investigated in the load range 8-50 N from 20 to 600 degree C. Wear transitions occurred at all temperatures but were load-dependent. The smoother sliding is thought to indicate a trend to oxide-oxide contacts. At higher temperatures wear transitions result in a two orders of magnitude reduction in wear. The corresponding friction transition was similar to the low temperature friction change but also included a marked temporary drop in the coefficient of friction. Pits or troughs up to 450 mu m deep were seen in wear scars above 400 degree C. It is proposed that isolated sections of grooves formed during the initial stages of wear become back-filled with loosely adhering oxide particles. These troughs are then further deepened, possibly by abrasive fretting action of the semi-fluid oxide material.