Abstract: A nanocrystalline layer is prepared on the 1Cr18Ni9Ti stainless steel by using supersonic fine particles bombarding (SFPB) surface nanocrystallization technique. And the grain size of the randomly oriented equiaxial nanograins is about 30 nm. Then, some of the original and SFPB treated (SFPBed) 1Cr18Ni9Ti samples are sulfurized by low-temperature ion sulfurization process and obtained sulfide layers, respectively. The tribological properties of the 1Cr18Ni9Ti before and after SFPB treatment and the corresponding two kinds of sulfide layers are investigated using a УТИ-1000 type ball-on-disk tribometer under dry friction. The results show that the tribological properties of 1Cr18Ni9Ti steel and the effectiveness of sulfurization are enhanced remarkably by surface nanocrystallization treatment. The friction coefficient of the SFPBed 1Cr18Ni9Ti steel with nanocrystalline surface layer descend from 0.65 to 0.45, while the thickness of the sulfide layer on the SFPB pretreated sample increased from 1 μm to 3.5 μm. These modifications can be mainly attributed to the high hardness, strength and chemistry activity of the nanocrystalline surface layer. The predominant wear mechanisms of the original 1Cr18Ni9Ti steel are abrasive wear and adhesive wear, and they transform to fatigue wear after surface nanocrystallization treatment.

Key words: 1Cr18Ni9Ti steel, Low-temperature ion sulfurization, Surface nanocrystallization, Tribological properties