Effect of Slide Diamond Burnishing on the Surface Layer of Valve Stems and the Durability of the Stem-Graphite Seal Friction Pair

This study analysed the condition of surface layer valve stems made 317Ti steel after polishing and burnishing. Surface roughness, microhardness, residual stress tests were carried out. The out to determine effect (especially non-standard parameters roughness) on durability valves possibility obtaining a favourable state by means sliding Significant differences observed in values roughness that tribological properties surface, higher microhardness compressive stresses obtained stem-graphite seal reciprocating movement was tested, failure-free operation time with burnished approximately four times longer, which is premise for recommending diamond burnishing as finishing treatment stems.