The article presents the impact of shot peening gears on their contact fatigue strength. Gears are made of indigenous material stainless 21NiCrMo2. The gears were subjected to a thermo-chemical treatment, which resulted in a surface hardness of 58-60 HRC. A series of gears was subjected to shot peening treatment. The gears were subjected to comparative fatigue tests on the circulating power machine. The fatigue testing programs carried out on the test bench have been developed on the basis of measurements of loads occurring in the driving system of the farm tractor during the performance of heavy agro-technical works. (c) 2018

The work presents the shot peening impact on microhardness measured in the cross-section of the gears tooth of carburized and tempered 21NiCrMo2 steel. This is the initial stage of verification of the parameters selection for the shot peening treatment of gears characterized by high surface hardness reaching 60 HRC. The main purpose of the work is to show differences in fatigue surface wear on the basis of conducted comparative studies on a circulating power machine. The analysis was based on illustrations of the tooth lateral surfaces and their cross-sections after having reached the base number of load cycles.