Method for repairing a blade of a one-piece bladed disc of aturbine engine and a test piece for implementing the method

Abstract

The procedure consists of first machining the damaged turbine blade (2) to prepare it for receiving a repair piece by cutting off a standard section (9) along a line (10). The repair piece is then attached to a test blade by an electron beam welding machine with pre-set operating parameters. After the qualities of the repair piece have been verified it is welded onto the prepared turbine blade repair zone using the same machine and operating parameters.

Description

technical field [0001] The invention relates to a repair method for repairing a single rotor blade of a turbomachine, and a test piece for starting, ending and commissioning of the method. Background technique [0002] A turbine consists of several rotors that turn around their axes. These rotors consist of a turntable with blades attached to the edges of the turntable. In the past, the blade was held by its root in a receptacle for this purpose. To meet the increasing performance requirements of engines, these rotors are now single-piece rotors, called blisks, or blisks. In the blisk, the blade and the turntable constitute only one part. For this purpose, the forged blank is machined to form a turntable, the blades extending radially around its circumference, but still as a single piece. It is also possible to weld specific components, or to create a monolithic turntable of monolithic components. The monolithic rotor has many advantages, not least in terms of quality. ...

AI Technical Summary

Problems solved by technology

[0007] However, problems arose in rotors made of a titanium alloy called Ti17

This alloy is mentioned in the patent application EP1340832, which refers to a product made of this material, such as a blade, which is rather difficult to weld because when it melts, gas volatilization occurs during welding, which will be in the heat-affected zone. (HAZ) generates micropores or pores, which will lead to a decrease in the mechanical properties of the welded zone

This drop can reduce mechanical strength by 80%

This drop due to electron beam welding cannot be tolerated in aerospace applications

Furthermore, in the case of Ti17 rotors, previously used TIG or microplasma techniques and operations commonly used in the aerospace industry were not able to provide acceptable results

[0008] In addition, recent blades have complex three-dimensional shapes, and their wall thickness varies, making it very difficult to use electron beam welding methods, which require precise parameters

These parameters must be well defined for each failure case, standardization is difficult to accomplish

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