When laser cladding is used to repair parts, the interaction of parameters has a significant influence on equipment performance. In order to explore the process parameters and quality of Ni60PTA coating, the statistical relationship between the process parameters (laser power, scanning speed, and powder feeding rate) and the responses (dilution ratio, ratio of layer width to height, and contact angle) was established by experiments using the response surface method (RSM) and variance analysis. The results show that the laser power is the dominant factor affecting the dilution ratio. However, the scanning speed has the greatest influence on the ratio of layer width to height and contact angle. These experimental results show that the proposed model can predict the actual data. In addition, the microstructure and microhardness of the samples prepared with the optimum process parameters were characterized. The results show that the quality of the cladding layer is good without cracks, deformation, and pores. The microstructure of the cladding zone is mainly composed of γ (Ni), FeNi3, M (M = Fe, Ni, Cr)23C6, M7C3, and CrB. The average microhardness of the coating is about 620 HV0.2, which is about 3.1 times that of 45 steel substrate.
In order to extend the service life of 45# steel and reduce production costs, coating NiCrBSi alloy powder on the surface of 45# steel can meet production requirements, avoid resource waste and achieve green manufacturing. Based on response surface method (RSM), the dilution rate, aspect ratio and contact angle were taken as the optimization goals, and the process parameters (laser power, scanning speed and powder feeding rate) were optimized and the optimal process parameters were determined. On this basis, the microstructure of Ni-based coating was characterized by the cladding experiment. The friction wear and corrosion resistance of the coating were tested, and the enhancement mechanism of the wear resistance and corrosion resistance of the coating was analyzed. The results show that the optimized coating has good corrosion resistance and wear resistance. It provides a reference for the optimization of process parameters in 45# steel repair work.
14 October 2023 in The International Journal of Advanced Manufacturing Technology
The FeCrSiNiCoC coatings with fine macroscopic morphology and uniform microstructure were made on 1Cr11Ni heat resistant steel substrate by a laser-based cladding technique. The coating consists of dendritic γ-Fe and eutectic Fe-Cr intermetallic with an average microhardness of 467 HV0.5 ± 22.6 HV0.5. At the load of 200 N, the average friction coefficient of the coating dropped as temperature increased, while the wear rate decreased and then increased. The wear mechanism of the coating changed from abrasive wear, adhesive wear and oxidative wear to oxidative wear and three-body wear. Apart from an elevation in wear rate with increasing load, the mean friction coefficient of the coating hardly changed at 500 °C. Due to the coating’s transition from adhesive wear and oxidative wear to three-body wear and abrasive wear, the underlying wear mechanism also shifted.
As a critical component of scraper conveyors, the middle trough operates under harsh conditions for extended periods, making it prone to failure and thus reducing the overall service life of the equipment. To address this issue and extend its service life, this study incorporated different amounts of CeO2 into Cr3C2/Fe-based composite coatings. It investigated the effects of CeO2 on the coating’s phase composition, microstructural evolution, wear resistance and corrosion resistance. Results show that CeO2 addition did not alter the coating’s phase composition. The composition remained α-Fe, M23C6 (M: Fe, Cr) and vanadium carbides. However, CeO2 promoted the transformation from columnar grains to equiaxed grains and refined the grains. With increasing CeO2 content, the composite coating’s mechanical properties gradually improved. The Ce2 coating exhibited the highest microhardness (923.08 HV0.5), the lowest friction coefficient (0.31) and the lowest wear rate (0.00217 mm3/N·m). Its dominant wear mechanisms were abrasive wear and mild adhesive wear. In 3.5% NaCl solution, the Ce2 coating showed the highest corrosion potential (−0.82 V) and the lowest corrosion current density (2.04 × 10−6 A/cm2), indicating excellent corrosion resistance. This study provides theoretical support for preparing high-performance Cr3C2/Fe-based composite coatings. It clarifies the key mechanism by which CeO2 regulates coating properties. The developed composite coating has broad application potential due to its excellent combined wear and corrosion resistance. It can be widely used for surface strengthening of vulnerable components in mining machinery such as scraper conveyors, offering important theoretical and technical support for improving the service life of scraper conveyor middle troughs.