A method for eliminating remelting layer of hole wall of single crystal superalloy by electric spark

Abstract

The invention belongs to the technical field of special machining of turbine blades of aero-engines, and in particular relates to a method for eliminating the remelted layer on the hole wall of single-crystal high-temperature alloy EDM holes, in particular to a method for realizing the aero-engine through the control of electric machining parameters and subsequent heat treatment process control. A method for eliminating the remelted layer on the gas film hole wall of a single crystal blade. By controlling the EDM process parameters and the cooling system, the superalloy epitaxial growth is realized, so that the remelted layer region and the superalloy matrix have exactly the same crystal orientation, and then the microstructure morphology of the remelted layer region is regulated through the heat treatment process. Make it consistent with the structure and morphology of the alloy matrix, thereby completely eliminating the interface between the original remelted layer and the alloy matrix, so as to improve the uniformity of the gas film hole wall structure of the turbine blade, and improve the fatigue resistance and creep resistance. The invention is simple and easy to implement, is especially suitable for large-scale batch production of single crystal turbine blades, and provides a technical solution for the preparation of high-quality gas film cooling holes without a remelted layer on the hole wall.

Description

technical field [0001] The invention belongs to the technical field of special processing of turbine blades of aero-engines, and in particular relates to a method for eliminating the remelted layer of the air film hole wall of the turbine blades of aero-engines through the control of electric machining parameters and subsequent heat treatment process control. Background technique [0002] Turbine blades are important hot-end components of aero-engines, and their reliability and stability are crucial to the safety of the overall engine. In order to improve the working efficiency of the engine, it is necessary to increase the temperature in front of the turbine accordingly. However, the turbine blades of advanced aero-engines are currently in service at a temperature exceeding their melting point. There are mainly two cooling methods: 1. Prepare a thermal barrier coating on the surface of the blade body to isolate high-temperature gas Direct impact on the airfoil; 2. Air film ...

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Problems solved by technology

[0004] Electroliquid beam machining is an electrochemical corrosion method and a non-hot-melt processing method. Although there is no remelting layer on the hole wall, there is an electrochemical corrosion layer, and the difference in the electrochemical potential of the γ phase and the γ' phase leads to a relatively rough surface of the hole wall. Poor, the formation of fatigue cracks on the hole wall may be induced during the long-term service of the blade

At the same time, the efficiency of electro-hydraulic beam machining is extremely low, and it is not suitable for industrial mass production

The single pulse duration of ultrafast laser processing is less than the time required for thermal diffusion of the lattice, which can realize "cold processing" in the true sense, but the cost of the equipment is high, the maintenance operation is complicated, and the processing efficiency is lower than that of EDM. Meet the production needs of large-volume turbine blades

[0005] Abrasive flow is a relatively mature process for removing the remelted layer on the hole wall, but this process is easy to damage the blade body, and when the initial state of the gas film hole diameter is inconsistent, the abrasive flow has a higher removal efficiency for the larger hole diameter of the gas film hole , while the removal efficiency of air film pores with smaller pore diameters is low, resulting in poor pore diameter consistency after processing

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