Selective Turbine Blade Tip Repair for Coated Armor-Plated Blades
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Solution Overview
Problem
Turbine blades with armor-plating and blade coatings can only be repaired a few times before reaching maximum permissible decoatings, leading to high costs and loss of wall thickness and strength, resulting in early scrapping.
Innovation Solution
A method involving selective removal of blade tip armor-coating and coating in the damaged area, followed by application of repair material and restoration of the original contour using machining, welding, or additive manufacturing, and reapplication of blade tip armor-plating and coating to minimize material loss and maintain strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If full decoating and full recoating of the turbine blade is performed, then the damaged blade tip can be repaired, but the wall thickness and strength of the blade body are reduced due to material removal
Solution Approach 1:
The repair process is segmented into localized operations only at the blade tip region. The armor plating and blade coating are removed only from the damaged blade tip area rather than the entire blade, allowing repair while preserving the intact coating and plating on the rest of the blade body, thus maintaining overall structural strength.
Solution Approach 2:
The repair method applies local quality by treating only the specific damaged region (blade tip) with selective decoating and recoating. The blade coating is preserved in non-damaged areas, creating a localized repair zone that maintains the original protective qualities elsewhere on the blade.
2Ease of repair
If full decoating and full recoating of the turbine blade is performed, then the damaged blade tip can be repaired, but the repair process becomes time-consuming and expensive
Solution Approach 1:
The repair process is divided into discrete localized steps: selective armor plating removal, selective blade coating removal, repair material application, and localized recoating. This segmentation eliminates the need for time-consuming full blade decoating and recoating operations, significantly reducing total repair time.
Solution Approach 2:
Instead of performing complete decoating and recoating of the entire blade, the method applies partial action by limiting all operations to only the damaged blade tip region. This partial approach achieves the necessary repair while avoiding the excessive time and cost associated with full blade processing.
3Ease of manufacture
If the blade coating is completely removed, then the repair surface can be prepared, but the number of permissible repairs is limited due to loss of wall thickness
Solution Approach 1:
The coating removal is segmented to affect only the blade tip region where damage exists. By dividing the blade into treated (tip) and untreated (body) zones, the method prepares the necessary repair surface while preserving the protective coating elsewhere, thereby extending the number of times the blade can be repaired over its lifetime.
Solution Approach 2:
Local quality is applied by maintaining the blade coating in non-damaged regions while removing it only where repair is needed. This localized approach preserves the protective function of the coating on the blade body, preventing cumulative wall thickness loss and extending the blade's service life through multiple repair cycles.
Data Source
AI summary
The invention relates to a method for repairing a damaged blade tip of a turbine blade which is armor-plated and provided with a blade coating, of a thermal gas turbine. The method according to the invention comprises the steps of removing a blade tip armor plating of the turbine blade at least in the region of the damaged blade tip and producing a repair surface (12), removing only a part of the blade coating of the turbine blade in the region of the repair surface while preserving a part of the blade coating separated from the repair surface (14), restoring the blade tip reinforcement (20), and restoring the blade coating in the region of the repaired blade tip (22). The invention furthermore relates to a device for carrying out such a method.