As the core component of the wind turbine transmission chain, the wind power gear plays a vital role in the safe and efficient operation of the whole machine. Wind power gears are subjected to varying degrees of wear on their contact surfaces due to alternating load impacts. For wind power gear repair and remanufacturing, laser cladding technology is proposed on the wind power gearbospline shaft. The effect of tungsten carbide (WC) addition on the laser-clad Fe-based coatings was investigated in this study. The morphology and composition of the composite coatings formed with different proportions of WC were studied using scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS). The microhardness and wear resistance were measured with a digital microhardness tester and a wear testing machine, respectively. The coatings were compact with no apparent cracks or pores and the microstructures of the regions above the fusion zone gradually changed from planar crystal to columnar crystal and cellular crystal, while the middle and upper parts of the coating mainly consisted of equiaxed crystals. The microhardness of the coatings gradually increased with the increase of WC content. The coating with 16% WC addition reached a maximum microhardness of 826.2 HV. The increase of WC content improved the wear resistance of the laser-clad Fe-based composite coatings. The wear mechanism of the coatings was mainly abrasive wear, along with slight adhesion wear and oxidative wear.

Web-core sandwich panels are a typical lightweight structure utilized in a variety of fields, such as naval, aviation, aerospace, etc. Welding is considered as an effective process to join the face panel to the core panel from the face panel side. However, it is difficult to locate the joint position (i.e., the position of core panel) due to the shielding of the face panel. This paper studies a weld position detection method based on X-ray from the face panel side for aluminum web-core sandwich panels used in aviation and naval structures. First, an experimental system was designed for weld position detection, able to quickly acquire the X-ray intensity signal backscattered by the specimen. An effective signal processing method was developed to accurately extract the characteristic value of X-ray intensity signals representing the center of the joint. Secondly, an analytical model was established to calculate and optimize the detection parameters required for detection of the weld position of a given specimen by analyzing the relationship between the backscattered X-ray intensity signal detected by the detector and the parameters of the detection system and specimen during the detection process. Finally, several experiments were carried out on a 6061 aluminum alloy specimen with a thickness of 3 mm. The experimental results demonstrate that the maximum absolute error of the detection was 0.340 mm, which is sufficiently accurate for locating the position of the joint. This paper aims to provide the technical basis for the automatic tracking of weld joints from the face panel side, required for the high-reliability manufacturing of curved sandwich structures.

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Web-core sandwich panels have gained the popularity in various fields, especially aviation and shipbuilding, etc. Penetration welding was considered as an effective process to manufacture such a structure through a T-joint. To ensure the formation quality and mechanical properties of weld, the welding torch needs to be aligned with the T-joint position. However, it is difficult to locate the T-joint position (i.e., the position of core panel) because of the shielding of the face panels. This paper investigated the detection of T-joint position from the face panel side in web-core sandwich panels based on eddy current technology. First, we designed an experimental system for the weld position detection of T-joints from the face panel side. The relationships are investigated between the characteristics of the eddy current detection signal and the primary parameters of the detection system (including excitation frequency, coil outer diameter, and lift off distance) and the T-joint (including thickness of the core panel, gap distance, and thickness of the cover panel). Corresponding experiments were carried out with variable primary parameters, and the influence mechanism of the primary parameters on the detection results in terms of sensitivity and dynamic performance was elaborated to set up the theoretical basis for the detection. Finally, weld position detection experiments were carried out on TC4 titanium alloy T-joint specimens with 3 mm-thick face panel and 5 mm-thick core panel. Results showed that the maximum detection error was 0.482 mm, and the average error was 0.234 mm. This paper provided a possible technical solution to the automatic tracking problem for the welding of T-joints in the web-core sandwich panels.