Abstract: The nuclear refueling machine is a critical component of a fuel handling and storage system in a pressurized water reactor (PWR) nuclear power plant. It is responsible for the operation of fuel assembly loading, unloading and transfer. The gripper of refueling machine had repeatedly jammed during the refueling process of nuclear power plant overhaul or the first loading process, which resulting in significant delays on the main overhaul line. The current research on the gripper jam phenomenon mainly concentrated on the structural enhancement of the gripper itself, with a paucity of research on the wear behavior between materials. Therefore, the wear damage mechanism between the cylinder block and the sleeve material was worthy of further investigation. 05Cr17Ni4Cu4Nb, which was used for the cylinder block and sleeve, was selected to form tribo-pairs with 05Cr17Ni4Cu4Nb, 06Cr18Ni11Ti and QSn7-0.2 for wear testing respectively, and the effects of different normal loads on the friction coefficients, wear morphology and wear damage mechanisms of the original and selected tribo-pairs at room temperature and dry environment were discussed. The results showed that: the friction coefficient of 05Cr17Ni4Cu4Nb increases sharply and then gradually rises to a stable trend at 10N, and the development stages were flat at 30N and 50N; the friction coefficients of 06Cr18Ni11Ti rapidly increased to a maximum and then showed an overall downward trend, those of QSn7-0.2 rapidly decreased after a sharp rise and gradually begin to fluctuate and gradually increased to a stable stage. At 10 N, the average friction coefficients of 06Cr18Ni11Ti and QSn7-0.2 were slightly lower than that of 05Cr17Ni4Cu4Nb, which were approximately 1.63; at 30N and 50N, the average friction coefficients of QSn7-0.2 were 0.98 and 0.88, respectively, which were significantly lower than those of 06Cr18Ni11Ti (1.07 and 0.98) and 05Cr17Ni4Cu4Nb (1.20 and 1.12). At 10 N, the dissipative energy of the three materials was close; when the normal load increases to 50 N, the dissipative energy of 06Cr18Ni11Ti and QSn7~0.2 was lower, which was 17.28% and 21.9% lower than that of 05Cr17Ni4Cu4Nb. The wear depths of 05Cr17Ni4Cu4Nb increased from 175 μm at 10 N to 373 μm at 50 N. In contrast, the wear depths of 06Cr18Ni11Ti and QSn7-0.2 decreased by 39.72% and 61.69% at 10 N, and decreased by 36.33% and 68.32% at 50 N, respectively. The wear rates of 05Cr17Ni4Cu4Nb and 06Cr18Ni11Ti decreased from 4.51×10⁻³ mm³/(N·m) to 2.79×10⁻³ mm³/(N·m) and from 2.34×10⁻³ mm³/(N·m) to 1.51×10⁻³ mm³/(N·m) respectively with the increased of load from 10N to 50N, while the wear rates of QSn7-0.2 were only 0.38 ×10⁻³ mm³/(N·m) and 0.21×10⁻³ mm³/(N·m) under the same condition. The wear mechanisms of both 05Cr17Ni4Cu4Nb and 06Cr18Ni11Ti under normal load were peeling and abrasive wear, QSn7-0.2 was abrasive wear and adhesive wear. Furthermore, the damage degree of QSn7-0.2 was lower owing to plastic self-lubrication. Oxidative wear occurs in three materials, and the main elements of 06Cr18Ni11Ti and QSn7-0.2 tend to form higher valence state with the increase of load.