Wear resistance improvement of sintered structural parts by C7H7 surface carburizing

Hِganنs NC 100.24 grade iron powder with 3 wt.% Mn and 0.8 wt.% C additions was used to produce the sintered gears. Those underwent the thermochemical cyclical treatment using hydrocarbons (C7H7), which resulted in carbides layer formation on the compacts. Three different thermochemical treatment conditions in terms of cycle number were chosen. The initial phase contents in the surface layer and its changes during the thermochemical cyclical treatment were studied by SEM analysis, metallography and microhardness measurements. The control of wear resistance was based on a set of two gears working together under specified rotation speed and load. The weight changes of those gears after 1 and 2 h of dry friction were controlled. A particular increase of wear resistance of the C7H7 carburized gears as compared with the untreated ones were observed.