Centrifugal Diffuser Blade Welding Through a Beam-Guiding Slot
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Solution Overview
Problem
The existing methods for assembling blades to a centrifugal diffuser cover in turbomachines, such as soldering and electron beam welding, face challenges like deformation, instability of the welding beam, and difficulty in joining pieces of different massiveness.
Innovation Solution
A method involving high energy welding, where a slot is made in the cover to guide the welding beam, allowing for the assembly of metal pieces with different massiveness without beam deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If soldering is used to attach blades to the diffuser cover, then the blades can be joined to the cover, but significant deformation and distortion of the diffuser occurs due to high temperature heat treatment
Solution Approach 1:
The patent changes the welding parameters by introducing a slot in the diffuser cover that guides the electron beam, allowing the beam to concentrate energy in a controlled manner. This parameter change enables welding at lower overall temperature exposure, reducing thermal deformation while maintaining joint strength
Solution Approach 2:
The slot acts as an intermediary element between the electron beam and the blade-diffuser interface. It guides and focuses the beam energy, mediating the heat transfer process to achieve precise localized welding without the widespread thermal affectation that causes distortion
2Reliability
If electron beam welding is used to join pieces of different massiveness (cover at least 2mm thick, blade top 0.3-2mm thick), then the risk of soldering radii and dripping is reduced, but the pieces cannot be molten together due to massiveness difference
Solution Approach 1:
The slot creates a localized region in the diffuser cover where the material is removed, creating a specific geometric configuration that facilitates electron beam penetration. This local modification allows the beam to reach and melt both the thin blade top and the thicker cover material simultaneously, overcoming the massiveness difference
Solution Approach 2:
The slot introduces a new dimensional feature (through-thickness opening) that changes the geometry of the joint zone. This dimensional change allows the electron beam to access the interface from the cover side, enabling welding of dissimilar thicknesses that would otherwise be incompatible
3Strength
If manual soldering is used to attach blades to the cover, then the blades can be joined to the cover, but poor wettability and lack of solder occur which are random and difficult to control
Solution Approach 1:
The patent replaces the manual mechanical soldering process with automated electron beam welding. This substitution eliminates the human operator's inability to control solder flow, providing precise, consistent, and repeatable welding results through automated beam control
Solution Approach 2:
The electron beam welding process is self-regulating through the slot geometry. The slot confines and guides the molten metal, allowing the welding process to self-control the filler material distribution without manual intervention, ensuring consistent weld quality
4Reliability
If multiple resolder operations are performed to correct soldering defects, then the joint quality can be improved, but each resolder operation requires complete soldering cycle with high temperature heat treatment causing cumulative deformation
Solution Approach 1:
The slot is prepared in advance before welding, creating optimal conditions for electron beam penetration and energy concentration. This preliminary preparation ensures that the welding process succeeds on the first attempt, eliminating the need for corrective resolder operations and their associated thermal deformation
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 enables stable and precise assembly of blades to the diffuser cover, reducing deformation and manufacturing complexity, while ensuring strong mechanical joints.
Implementation Method 1
welding, through the slot, the second metal piece to the first metal piece with a high energy welding beam
Implementation Method 2
The high energy welding beam makes it possible to locally melt the metal of the first metal piece and of the second metal piece
Data Source
AI summary
A method for assembling a first metal part to a second metal part, the first and second metal parts having different sizes, the method including the following operations a) producing a slot in a surface of the first metal part; b) positioning the second metal part in line with the slot of the first metal part; and c) welding the second metal part to the first metal part through the slot using a high-energy welding beam, the slot guiding the welding beam.