Wear and Galling of 356-T6 Aluminum-on-Steel in Low Amplitude Reciprocating Sliding in the Presence of Synthetic Lubricants in HFC-134a Atmosphere

Abstract

The wear and galling of 356-T6 aluminum against steel in low amplitude reciprocating motion (5° oscillation) has been studied in a block-on-ring wear test machine. The lest utilized stepwise increasing loads (9-454 kg range) lubricants in CFC-12 or HFC-134a refrigerant atmospheres. For three lubricants utilized [a mineral oil (M100), a polyalkylene glycol (U8), and an esterified polypropylene oxide glycol (D1)] damage on the aluminum surface increased according to the sapience.: CFC-12/M100 < HFC-134a/M100 < HFC-134a/D1 < HFC-134a/U8 with the lowest wear and almost no galling for the CFC-12/M100 case and the highest wear and severe galling for the HFC-134a/U8 case. Formation of halide (mainly chloride) antiwear and FP films is responsible for protecting the aluminum surface in the CFC-12/M100 case. For the HFC-l34a/M100 case, the low solubility of HFC-134a in M100 (which prevents removal of the lubricant film from the surface) is most likely (although not observed directly in this work) responsible for low wear and galling. The absence of oil or antiwear films is responsible for aluminum transfer to steel resulting in high wear and galling for the HFC-134a/U8 case. A small degree of interaction between aluminum and the esterified glycol offers some protection in the HFC-134a/D1 case. Aspects of the wear mechanisms responsible for the observed effects on the aluminum surface are discussed. Aluminum wear rates and wear coefficients are also presented.

Presented at the 50th Annual Meeting in Chicago, Illinois May 14–19, 1995

KEY WORDS:

• Aluminum
• Synthetic Lubricants
• Wear and Failure

Notes

Presented at the 50th Annual Meeting in Chicago, Illinois May 14–19, 1995