Electrochemical Broaching of Inconel 718 Turbine Mortises

Area of Science:

• Materials Science
• Manufacturing Engineering
• Electrochemistry

Background:

• Turbine mortise quality is crucial for aircraft engine performance and lifespan.
• Conventional mechanical broaching of nickel-based superalloys causes severe tool wear, increasing production costs.
• Electrochemical broaching (ECB) presents a wear-free, cost-effective alternative for turbine mortise fabrication.

Purpose of the Study:

• To investigate and optimize the electrochemical broaching process for Inconel 718 turbine mortises.
• To simulate the multiphysics field during ECB and establish a material dissolution model.
• To demonstrate the feasibility of manufacturing high-quality fir-tree turbine mortises using ECB.

Main Methods:

• Multiphysics simulation using COMSOL 6.2 to analyze electric, flow, temperature, and bubble fields.
• Experimental electrochemical broaching of Inconel 718 specimens at various feed speeds.
• Analysis of material dissolution states and process parameter optimization.

Main Results:

• Identified five distinct dissolution states during the ECB process.
• Successfully manufactured fir-tree turbine mortises on Inconel 718 with dimensional deviations of (+16 to -21) μm.
• Achieved high-quality surfaces (Ra 0.275 μm) with excellent consistency and demonstrated tool cathode reusability without wear.

Conclusions:

• Electrochemical broaching is a viable and efficient method for producing turbine mortises in advanced nickel-based superalloys.
• Optimized ECB parameters ensure high precision, surface integrity, and process repeatability.
• ECB significantly reduces manufacturing costs by eliminating tool wear.