Rail cladding is a cost-effective approach for track maintenance and protection from rapid growth of mileage and Rolling Contact Fatigue (RCF) phenomenon. In this study, cladding layers are prepared on the surface of a U75V rail substrate using a plasma cladding approach with different substrate preheating temperatures. Preheating of the substrates creates an isothermal treatment for the cladding material after solidification of the molten pools. The effects of these post-solidification isothermal treatment temperatures (480°C, 340°C, and 200°C) on microstructures, mechanical properties and corrosion resistance are studied. The results indicate that the post-isothermal treating temperature affects the fractions of granular bainite, upper bainite, lower bainite, martensite and M/A island in the microstructure. The hardness of cladding layers is higher than that of the U75V substrate, and slightly increases as the pretreating temperature decreases. The specimen prepared at 340 °C has the highest tensile strength, which is 14.5% higher than the U75V rail. The interface between the cladding layer and the substrate also processes a strong bonding with the bonding strength of 789 MPa. Based on the comprehensive performance, the post-isothermal treating temperature of 340 °C is most suitable for cladding on the U75V rail. The plasma cladding process followed by post-isothermal treatment proves to be a flexible and effective approach to manipulate the microstructure of the cladding and restore the properties of the rail substrate.

铁路覆层是一种经济高效的方法，可用于维护轨道并保护其免受里程的快速增长和滚动接触疲劳（RCF）现象的影响。在这项研究中，使用等离子熔覆方法在不同的基板预热温度下，在U75V轨道基板的表面上制备熔覆层。基板的预热在熔池固化后对包层材料进行等温处理。研究了这些凝固后的等温处理温度（480°C，340°C和200°C）对组织，力学性能和耐腐蚀性的影响。结果表明，等温后热处理温度会影响组织中粒状贝氏体，上贝氏体，下贝氏体，马氏体和M / A岛的含量。覆盖层的硬度高于U75V衬底，并且随着预处理温度的降低而略有增加。在340°C下制备的样品具有最高的拉伸强度，比U75V导轨高14.5％。包层和基板之间的界面也以789 MPa的结合强度进行牢固的结合。基于综合性能，等温后处理温度340°C最适合用于U75V导轨上的覆层。经过等温后处理的等离子熔覆工艺被证明是一种灵活有效的方法，可处理熔覆层的微观结构并恢复轨道基板的性能。在340°C下制备的样品具有最高的拉伸强度，比U75V导轨高14.5％。包层和基板之间的界面也以789 MPa的结合强度进行牢固的结合。基于综合性能，等温后处理温度340°C最适合用于U75V导轨上的覆层。经过等温后处理的等离子熔覆工艺被证明是一种灵活有效的方法，可处理熔覆层的微观结构并恢复轨道基板的性能。在340°C下制备的样品具有最高的拉伸强度，比U75V导轨高14.5％。包层和基板之间的界面也以789 MPa的结合强度进行牢固的结合。基于综合性能，等温后处理温度为340°C最适合用于U75V导轨上的覆层。经过等温后处理的等离子熔覆工艺被证明是一种灵活有效的方法，可处理熔覆层的微观结构并恢复轨道基板的性能。340°C的等温后处理温度最适合用于U75V导轨上的覆层。经过等温后处理的等离子熔覆工艺被证明是一种灵活有效的方法，可处理熔覆层的微观结构并恢复轨道基板的性能。340°C的等温后处理温度最适合用于U75V导轨上的覆层。经过等温后处理的等离子熔覆工艺被证明是一种灵活有效的方法，可处理熔覆层的微观结构并恢复轨道基板的性能。