Assessments on friction and wear behaviors of P110 steel and chromizing coating sliding against two counterparts under dry and wet conditions

Chromizing coating was fabricated on P110 oil casing tube steel by employ of pack cementation to improve the performance and increase the life-time during operation. Scanning electron microscope (SEM), X-ray diffraction (XRD), glow discharge optical emission spectroscope (GDOES) and microhardness tester were used to investigate the surface morphology, cross-sectional microstructure, phase constitutions, element distribution and microhardness distribution of the coating. Friction and wear behaviors of P110 steel and chromizing coating were measured using a ball-on-disc type tribometer under sliding against two counterparts in dry and wet conditions. The variations in friction coefficient, mass loss and surface morphologies of the tested samples were systemically investigated and analyzed. Energy dispersive spectrometer (EDS) and SEM were employed to elucidate the wear mechanisms of the tested samples. The results showed that the obtained coating was uniform and compact, mainly consisted of MxCy and reached a thickness of 55 μm. Chromizing coating had higher surface hardness and lower mass losses than that of P110 steel. When sliding against GCr15, chromizing coating showed no obvious friction–reduction effect, but indicated certain anti-friction property in sliding against Si3N4. The tested samples varied with surface hardness values and surface compositions have shown different wear mechanisms in the sliding tests. Chromizing treatment makes it possible to create on the working surface of P110 steel with enhanced surface hardness and wear resistance.