An experimental investigation of galling phenomenon generated in an alternated sliding ring-on-ring interface: Application to a full-scale solid lubricant interface

A fully instrumented ring-on-ring galling test has been developed based on the ASTM G196 test principle. Torque records allow computation of the coefficient of friction and other tribological parameters to capture wear behavior of the interface. Contact electrical resistance is also recorded helping to detect galling onset in the contact. A solid lubricant anti-galling solution in OCTG connections involving a coated versus steel interface has been studied. Tests have been stopped at different sliding distances to perform surface analysis and characterize wear mode and severity. Wear scars have been expertized using optical, SEM, EDS, surface and μ-hardness profile analysis such that the degradation scenario of the coating and the steel surface can be drawn up. Moreover, an analysis in terms of friction coefficient can be developed describing the evolution from pure lubricated interface to fully galled interface. •Development of an ASTM G196 like macro ring-on-ring test system.•Investigation of the onset galling phenomena of a solid lubricant interface.•Couple analysis of the coefficient of friction, acoustic emission and electrical contact resistance.•The sigmoid evolution of COF is monitored by the galling area extension.•The incipient galling process is related to very low 0.12 friction coefficient.