Tribological behavior and applicability analysis of cast iron and iron-based powder metallurgy for rolling piston rotary compressor under different applied loads

摘要

The tribological behaviors and applicability analysis of HT250 cast iron and iron-based powder metallurgy under different applied loads were compared experimentally. The friction coefficients and wear characteristics were measured with the changing operating load at a certain rotational speed by a ring-on-ring test rig. Results show that the tribological advantage is strongly dependent on the lubrication regime of frictional surfaces. The powder metallurgy presents better frictional performance in hydrodynamic lubrication when the applied load is less than 400 N. Still, with the applied load increasing beyond 400 N, the HT250 cast iron shows better frictional advantages in mixed lubrication. The Stribeck curve also shows the critical loads from hydrodynamic into mixed lubrication for the HT250 cast iron and powder metallurgy are about 300 N in present cases. Besides, with the increased applied load, the HT250 cast iron presents better anti-wear performance. The wear mechanism transforms from a significant abrasive feature to abrasive and oxidative wear.