Non-machined Surface Protection Process of Electrochemical Machining Based on Repaired Turbine Blade

Abstract

In order to improve the efficiency of turbine blade repairing, protection processes of non-machined surface in Electrochemical Machining (ECM) based on blade repairing were studied. Mathematical model of electric field was developed to obtain current density distribution on anode surface, and to study the repairing principle and consequently analyze the defects forming mechanism by conventional electrolytic repair process. Sacrificial layer process was proposed to protect the non-machined surface in this work and an experimental system was developed to shape overlay welded TC4 blades. The results show that directly shaping process and insulated layer process produce stray dissolution and "stair" defects respectively,while sacrificial layer process achieves acceptable machining performance. With shaping time of 60s, the efficiency is improved; shaped blades have higher precision and surface roughness is Ra≤0.6μm, and with higher repeatability, the design requirements can be met.

Keywords

• blade tip
• repairing
• electrochemical machining (ECM)
• numerical calculation
• sacrificial layer process