Diaphragm Rail Cladding Repair for Wear-Resistant Turbomachinery
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Solution Overview
Problem
Current methods for repairing turbomachine diaphragms are inefficient and do not extend the service life of the repaired components beyond that of a new diaphragm, often requiring extensive machining and replacement of entire sections rather than targeted repairs.
Innovation Solution
A method involving machining worn diaphragm rail sections to create a clean surface, filling the dimension differences with austenitic stainless steel cladding, and welding multiple layers to restore the affected area, followed by machining to nominal dimensions, reducing material waste and machining costs while extending service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If extensive machining and replacement of entire sections is performed, then the diaphragm can be repaired, but material waste and machining costs increase significantly
Solution Approach 1:
The patent applies local quality by performing machining and cladding only on the worn portions of the diaphragm rail rather than the entire component. The worn area is selectively identified and processed, preserving the remaining serviceable material and reducing overall material waste while maintaining repair quality.
Solution Approach 2:
The repair process is segmented into distinct stages: machining the worn area to a clean surface, applying cladding material to restore dimensions, and performing final machining to achieve nominal dimensions. This segmentation allows targeted repair of only the affected areas rather than replacing entire sections.
2Manufacturing precision
If multiple layers of cladding are welded to restore nominal dimensions, then the worn area is fully repaired, but the welding process becomes more complex and time-consuming
Solution Approach 1:
The machined surface is prepared in advance with precise geometry and clean conditions before cladding application. This preliminary machining creates an optimal base surface that facilitates smoother cladding deposition and reduces the number of corrective passes needed, simplifying the overall welding process.
Solution Approach 2:
The repair restores three-dimensional nominal dimensions through sequential cladding layers. Each layer builds upon the previous one, progressively restoring the worn area to its original geometry in multiple dimensional aspects (height, width, depth) rather than attempting single-pass correction.
3Duration of action of stationary object
If the diaphragm is repaired to extend service life beyond a new diaphragm, then component longevity increases, but the repair process requires more sophisticated techniques and materials
Solution Approach 1:
The patent employs composite material construction by applying cladding material over the machined base metal. This composite structure combines the existing diaphragm rail material with additional cladding material to restore and enhance the component, achieving extended service life through material reinforcement rather than simple replacement.
Solution Approach 2:
The repair process changes material parameters by applying cladding with different properties than the base material. This allows optimization of specific properties such as wear resistance, corrosion resistance, or thermal characteristics in the repaired areas, enabling service life extension beyond the original component capabilities.
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
This method efficiently repairs only the worn parts of the diaphragm, using austenitic stainless steel cladding to enhance durability and extend service life beyond that of a new diaphragm, reducing mechanical stress through symmetric cross-sectional machining and optimized welding parameters.
Implementation Method 1
wherein at least one welding layer includes several weld passes welded in close proximity to each other such that a compact cladding is achieved
Data Source
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AI summary
The claimed method describes refurbishing of worn diaphragm rails (38, 39) for turbo machines. This method comprises machining the worn part of the diaphragm rails such that a clean and geometrically exact machined surface is achieved. Welding one or more layers on these machined surfaces builds up a cladding that overtops the nominal dimensions of new diaphragm (30). The method further comprises machining the cladding such that it has the nominal dimensions of a new diaphragm.