Because of the low viscosity of high-water-based fluids, the intense wear and leakage of key friction pairs represent a bottleneck to the wide application of the high-water-based hydraulic motor in engineering machinery. In this work, based on the common characteristics of plane friction pairs, the friction experiments of a 316L stainless steel (316L)–polytetrafluoroethylene (PTFE) friction pair under various working condition were carried out by a self-designed friction experimental system with fluid lubrication. The influence of lubrication pressure and surface morphology on the 316L–PTFE friction pair was investigated both experimentally and theoretically. The experimental and numerical results indicated that increasing lubrication pressure reduced the surface wear of PTFE sample, but the leakage of 316L–PTFE friction pair also increased. It could not form an effective fluid lubrication film in the 316L–PTFE friction pair under low lubrication pressure, which caused the severe wear in friction pair interface. The smooth 316L surface could be conducive to the formation of high-water-based fluid lubrication film in 316L–PTFE friction interface. The pressure distribution of high-water-based fluid lubrication film in 316L–PTFE friction pair was also obtained in fluent. The PTFE surface was easily worn when the lubrication film in the friction pair was too thin or uneven. The friction and wear were obviously improved when the normal load was balanced by the bearing capacity of the high-water-based fluid lubrication film.

In the process of laser-based direct energy deposition (DED-LB), the quality of the deposited layer will be affected by the process parameters and the external environment, and there are problems such as poor stability and low accuracy. A molten pool monitoring method based on coaxial vision is proposed. Firstly, the molten pool image is captured by a coaxial CCD camera, and the geometric features of the molten pool are accurately extracted by image processing techniques such as grayscale, median filtering noise reduction, and K-means clustering combined with threshold segmentation. The molten pool width is accurately extracted by the Canny operator combined with the minimum boundary rectangle method, and it is used as the feedback of weld pool control. The influence of process parameters on the molten pool was further analyzed. The results show that with an increase in laser power, the width and area of the molten pool increase monotonously, but exceeding the material limit will cause distortion. Increasing the scanning speed will reduce the size of the molten pool. By comparing the molten pool under constant power mode and width control mode, it is found that in width control mode, the melt pool width fluctuates less, and the machining accuracy is improved, validating the effectiveness of the real-time control system.

The low yield strength and hardness of high-carbon and high-manganese steel before deformation limit its wide application under impact load conditions. In order to improve the dynamic mechanical properties of high-carbon and high-manganese steel under impact load and extend its service life, laser wire additive manufacturing technology was adopted to strengthen the high-carbon and high-manganese steel. This study used laser wire additive manufacturing technology to prepare high-carbon and high-manganese steel samples on a cast high-manganese steel substrate. The mechanical properties of a separated Hopkinson pressure bar under impact loading were quantitatively studied, and the microstructure before and after the dynamic compression process was analyzed using characterization methods such as optical microscopy, scanning electron microscopy, electron probe X-ray microscopy, electron backscatter diffraction, and transmission electron microscopy to reveal the deformation and strengthening mechanisms. The results showed that the yield strength of high-carbon and high-manganese steel prepared via laser wire additive manufacturing technology under impact load reached (764±10) MPa, the hardness increased from (314±7) to (619±22) HV_0.3, and the work hardening index was 0.88, all higher than those of cast high-manganese steel. Among these, the high yield strength is attributed to the strengthening of grain boundaries and dislocations caused by heterogeneous microstructures, accounting for 60%. The generation of dislocation networks, stack fault networks, and nanotwins during dynamic compression maintains excellent work hardening ability. The use of laser wire additive manufacturing technology to prepare high-carbon and high-manganese steel and study its mechanical properties and microstructure evolution under impact load provides a new method for high-performance repair and remanufacturing of large high-manganese steel components in mining machinery, which is crucial.