Turbine Blade Tip Insert Brazing for Deep Crack Repair
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Solution Overview
Problem
Conventional methods for repairing deep tip cracks in turbine blades are inefficient and require skilled labor, limiting the repairability of airfoils with cracks beyond a certain depth and being time-consuming.
Innovation Solution
A method involving machining the turbine blade to create a groove for an insert made from pre-sintered preform material, which is then welded and brazed into place using a welding alloy and brazeable paste, allowing for deeper crack repair and extending the blade's lifetime.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional grinding and welding methods are used to repair tip cracks, then shallow cracks can be repaired, but deep tip cracks cannot be effectively repaired
Solution Approach 1:
The repair process is divided into distinct segments: machining the groove to remove cracked material, placing the pre-sintered preform insert, welding the insert to the blade, and brazing the tip cap. This segmentation allows each step to be optimized independently, enabling deep crack repair while maintaining manageable complexity.
Solution Approach 2:
The insert is pre-sintered into a preform before being placed in the groove, and the tip cap is pre-brazed to the insert. These preliminary actions prepare the components in advance, making the final assembly and welding steps more efficient and enabling the repair of deeper cracks that would be impossible with conventional direct welding methods.
2Manufacturing precision
If skilled labor is used for conventional repair methods, then repair quality can be maintained, but repair time increases significantly
Solution Approach 1:
The pre-sintered preform insert is designed to self-align and self-support within the machined groove during welding, reducing the need for skilled manual positioning and manipulation. The brazing process also provides self-leveling characteristics, allowing less skilled workers to achieve consistent repair quality while reducing overall repair time.
3Duration of action of stationary object
If tip cap cooling is added to extend component lifetime, then blade lifetime increases, but manufacturing complexity increases due to manufacturing constraints
Solution Approach 1:
The tip cap with integrated cooling channels is brazed onto the pre-sintered preform insert, which is already welded to the blade. This nested structure allows the cooling functionality to be added without requiring complex internal modifications to the blade itself, extending component lifetime while managing manufacturing complexity through modular assembly.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables fast and cost-effective repair of turbine blades with deep tip cracks, extending their useful lifetime and making them suitable for re-use, applicable to other hot gas path components as well.
Implementation Method 1
The insert is welded and brazed into place
Implementation Method 2
The insert is welded and brazed into place
Data Source
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AI summary
The present application provides a method of repairing a turbine blade (100). The method may include the steps of removing an existing tip cap (190) from the turbine blade (100) in whole or in part, machining the turbine blade (100) to form a machined groove (220), positioning an insert (230) in the machined groove (220), welding the insert (230) to the turbine blade (100), and brazing the turbine blade (100).