汽轮机叶片冲蚀区的激光修复与强化

针对汽轮机叶片激光修复及强化后的组织和性能特点,进行了2Cr13叶片冲蚀区激光熔覆修复和合金强化的实验研究,并在实验完成后对叶片进行了取样,分析和测试了其显微组织、硬度、耐磨损以及耐汽蚀等性能.结果表明:激光修复层与基体结合紧密;修复层组织由(Fe,C,Cr)过饱和固溶体枝晶和枝晶间CrC组成,而合金强化层组织为(Fe,C,W,Cr)过饱和固溶体枝晶、网络状(Fe,C,W)共晶以及Fe3C、WC和W2C组成;修复层平均硬度为350 HV0.2,合金强化层平均硬度为800HV0.2;修复层和合金强化层的耐磨损性能比叶片基体分别提高了1倍和3倍以上.修复层和合金强化层的耐气蚀性能比基体分别提高了0.5倍和2倍以上.修复强化后的叶片性能优于新叶片,能较大地提高叶片的使用寿命.

Repairing and Strengthening of Eroded Turbine Blades by Laser Technology

In order to study the microstructure features and mechanical properties of an eroded 2Cr13 turbine blade repaired and strengthened,a series of experimental tests were carried out,including the metallographic examination,hardness,anti-abrasive and anti-cavitation erosion test.Results show that the repairing layer,which is made up of supersaturated solid solution dendrite(Fe,C,Cr) and interdendritic carbide(CrC),bonds with the substrate soundly,and the strengthening layer consists of supersaturated solid solution dendrite(Fe,C,W,Cr),netlike eutectic(Fe,C,W) and carbide(WC,W_2C,Fe_3C).The repairing layer has an average hardness of 350HV0.2 while the strengthening layer 800HV0.2.Compared with the substrate,the anti-abrasive property of both the repairing and strengthening layer has been increased respectively by 1 and 3 times,and the corresponding anti-cavitation corrosion property increased by 0.5 and 2 times.Since the repaired and strengthened turbine blade has a better comprehensive property than new ones,its service life will certainly be elongated.