Turbine Blade Erosion Shield via Backing Plate Mediator
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Solution Overview
Problem
Turbine blades in power generation systems face erosion from water droplets and fine dust, leading to loss of chord width, efficiency, and fatigue due to residual stresses from build-up welding, which existing methods fail to adequately address.
Innovation Solution
A method involving the use of a backing plate to support the deposition of erosion-resistant materials via fusion bonding, forming an erosion shield on the leading edge of the blade, and subsequent removal of the backing plate to eliminate diffusion layers, allowing for stronger, less stressed joining of dissimilar metals and reduced cycle times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If build-up welding is used to increase erosion resistance, then erosion protection is improved, but residual stresses cause spalling and cracking
Solution Approach 1:
A backing plate made of low carbon steel is introduced as an intermediary substrate during the laser cladding process. The erosion resistant material is deposited on the backing plate rather than directly on the blade, allowing the diffusion layer to form between the blade and backing plate instead of within the erosion shield itself. This mediator approach prevents residual stress accumulation in the erosion shield while maintaining erosion protection.
Solution Approach 2:
The process segments the erosion shield formation into two distinct stages: first depositing erosion resistant material on the backing plate, then removing the backing plate along with the diffusion layer. This segmentation allows the erosion shield to be formed without the harmful diffusion layer that would otherwise be embedded in it, resolving the contradiction between erosion protection and structural integrity.
2Reliability
If multiple layers of erosion resistant material are deposited, then erosion shield thickness is improved, but manufacturing time increases
Solution Approach 1:
The backing plate is prepared in advance and positioned on the blade before the laser cladding process begins. This preliminary setup allows for more efficient deposition of multiple erosion resistant layers since the backing plate provides a stable, extended surface for material accumulation. The pre-positioned backing plate enables faster processing compared to direct blade deposition, reducing overall manufacturing cycle time while achieving the required shield thickness.
3Strength
If diffusion layer is present at the interface, then bonding strength is improved, but erosion resistance is reduced
Solution Approach 1:
The diffusion layer, which forms at the interface between the erosion resistant material and the blade substrate, is selectively removed along with the backing plate after the erosion shield is formed. This extraction eliminates the harmful diffusion layer that would compromise erosion resistance while the erosion shield itself retains sufficient bonding strength through the laser cladding process. The diffusion layer is taken out because its location at the blade interface creates a weak point for erosion initiation.
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
The method enhances the durability and accuracy of erosion shield application, reduces overspray, and eliminates additional machining steps, resulting in a more efficient and resilient turbine blade design.
Implementation Method 1
depositing an erosion resistant material in a plurality of layers by fusion bonding the erosion resistant material to the forward face of the leading edge surface
Implementation Method 2
heat treating the blade and the erosion shield
Data Source
AI summary
Methods of forming a blade and rendering a blade resistant to erosion includes positioning a backing plate(s) or elongated backing plate(s) adjacent at least one side of a forward face of a leading edge surface of the blade. The methods include depositing an erosion resistant material in a plurality of layers by fusion bonding the erosion resistant material to the forward face of the leading edge surface of the blade. The backing plates providing a template or guide for depositing the plurality of layers of erosion resistant material. The plurality of layers of erosion resistant material form an erosion shield and a leading edge of the blade. Methods include removing the backing plate.