汽轮机叶片钢超音速火焰喷涂层和等离子喷焊层性能研究

Performance of Supersonic Flame Spray Coating and Plasma Spray Welding Layer for Turbine Blade Steel

目的提高汽轮机叶片钢1Cr12Ni2W1Mo1V的抗微粒冲蚀性能和抗水蚀性能。方法利用超音速火焰喷涂技术和等离子喷焊技术在其表面分别制备了Cr3C2-NiCr75-25涂层、WC-10Co-4Cr涂层和Stellite 6合金喷焊层。借助扫描电镜(SEM)观察3种涂层水蚀凹坑的微观组织形貌,并对3种涂层的显微硬度、抗摩擦磨损性能、抗微粒冲蚀性能和抗水蚀性能进行分析。结果3种涂层的平均显微硬度较基体均有显著提升,其中WC-10Co-4Cr涂层的平均显微硬度最高,其值为1314.6HV4.9 N。以Stellite 6合金涂层为摩擦副,Cr3C2-NiCr75-25涂层的摩擦系数为0.5~0.7,失重0.0131 g,而WC-10Co-4Cr涂层的摩擦系数为0.5~0.6,失重0.0007 g,显然WC-10Co-4Cr涂层的抗摩擦性能更好。抗微粒冲蚀性能试验中,最大磨痕深度由深到浅依次为:基体材料(94.658μm)、Stellite 6合金层(85.932μm)、Cr3C2-NiCr75-25涂层(81.163μm)、WC-10Co-4Cr涂层(11.864μm)。其对应的磨损率也逐渐减小。表面水蚀沟槽最大深度依次为:基体材料(445μm)、Stellite 6合金层(70μm)、Cr3C2-NiCr75-25涂层(80μm)、WC-10Co-4Cr涂层(41μm)。其对应造成的质量损失由30 mg/cm^2逐渐变为3.3 mg/cm^2。结论3种涂层均具有一定的抗摩擦磨损性能、抗微粒冲蚀性能和抗水蚀性能,其中WC-10Co-4Cr涂层的各项性能均最佳,主要是该涂层中弥散分布了大量WC硬质相,使其显微硬度最高,加之其他相关性能共同作用的结果。

The work aims to improve the particle erosion resistance and water erosion resistance of turbine blade steel 1Cr12Ni2W1Mo1V.Cr3C2-NiCr75-25 coating,WC-10Co-4Cr coating and Stellite 6 alloy spray welding coating were respectively prepared on the base metal by supersonic flame spraying and plasma spray welding.The microstructures of the three coatings were observed by SEM and the micro-hardness,friction and wear resistance,particle erosion resistance and water erosion resistance of the three coatings were tested and analyzed.The average micro-hardness of the three coatings was significantly higher than that of the base metal,especially the average micro-hardness of WC-10Co-4Cr coating was the highest,with a value of 1314.6 HV4.9 N.Stellite 6 alloy coating was used as friction pair,the friction coefficient of Cr3C2-NiCr75-25 coating was between 0.5 and 0.7,with a weight loss of 0.0131 g,while that of WC-10Co-4Cr coating was between 0.5 and 0.6 with a weight loss of 0.0007 g.Obviously,WC-10Co-4Cr coating had better friction performance.In the test of particle erosion resistance,the maximum wear mark depth of the coating from deep to shallow was:base metal(94.658μm),Stellite 6 alloy coating(85.932μm),Cr3C2-NiCr75-25 coating(81.163μm),and WC-10Co-4Cr coating(11.864μm).The corresponding wear rates of the coatings were also gradually reduced.The maximum depth of water erosion groove on the surface from deep to shallow was:base metal(445μm),Stellite 6 alloy coating(70μm),Cr3C2-NiCr75-25 coating(80μm),and WC-10Co-4Cr coating(41μm)and the corresponding mass loss gradually changed from 30 mg/cm^2 to 3.3 mg/cm^2.The three kinds of coatings have certain friction and wear resistance,particle erosion resistance and water erosion resistance,among which WC-10Co-4Cr coating has the best performance due to the highest micro-hardness caused by the dispersion of a large number of WC hard phase in the coating and the synergistic effect of other related properties.