Wear resistance improvement of 100CrMnSi6-4 bearing steel by laser boriding using CaF2 self-lubricating addition

摘要

Laser-alloyed layer with boron and CaF2 self-lubricating addition was produced on 100CrMnSi6-4 bearing steel. The produced layer was free of cracks or gas pores and uniform in respect of the thickness because of the high overlapping (86%). The microstructure consisted of re-melted zone and heat-affected zone. The re-melted zone included dendritic or globular iron borides with limited percentage of eutectic mixture in which CaF2 particles were located. Martensite and retained austenite occurred in heat affected zone. Tribofilm, consisting of CaF2, was observed on the worn surface and was the reason for improved wear resistance compared to the laser-alloyed layer with boron only. In areas, in which tribofilm was thin or almost invisible, an intensive abrasive or oxidative wear proceeded. (C) 2016 Elsevier Ltd. All rights reserved.