Abstract
The repairing and strengthening of steam eroded turbine blades by laser direct metal deposition (DMD) forming technology were researched in this article. Based on the numerical calculation method of finite element, primary technology parameters of DMD were simulated. The microstructure and properties (such as hardness, anti-abrasive) of test specimen of repaired and strengthened blades were tested. The repaired layer has excellent bonding with substrate. The microstructure of repaired layer is typical cellular dendritic including (Fe,C,Cr) supersolubility solid solution and the interdendritic CrC. The microstructure of hardened layer consists (Fe,C,W,Cr) supersolubility solid solution and (Fe,C,W) eutectic. The average hardness of repaired layer and strengthened layer are HV_<0.2>350 and HV_<0.2>800 respectively, while the hardness of substrate is HV_<0.2>250. The anti-abrasive properties of repaired specimen and hardened specimen increase one time and three times than the substrate, respectively.
