Stator Blade Ferrule Welding with Flange Pre-Tension Compensation
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Solution Overview
Problem
The welding of blades to the shroud in turbomachine bladed elements generates internal stresses and deformations, particularly in the flanges, which require post-welding machining to correct, limiting further machining operations if a non-compliant vane needs replacement.
Innovation Solution
A method involving a tool that exerts tensile forces on the flanges before and after welding to elastically deform the flanges and ferrule, compensating for shrinkage effects, allowing the bladed element to return to its original shape and position, thereby eliminating the need for extensive post-welding corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is performed to join blades to the shroud, then the bladed element achieves structural integrity, but internal stresses cause deformations of the flanges requiring post-welding machining
Solution Approach 1:
The patent applies preliminary action by mounting the tooling on the shroud before welding to pre-position the flanges in the correct alignment. The tooling exerts forces on the flanges during welding to compensate for anticipated shrinkage deformations, ensuring that after welding and removal of the tooling, the flanges maintain their original positions and shapes without requiring extensive post-welding machining.
Solution Approach 2:
The patent applies preliminary anti-action by using the tooling to exert opposing forces on the flanges that counteract the anticipated welding-induced shrinkage and deformations. The tooling is configured to apply forces in directions that will compensate for the internal stresses generated during welding, thereby preventing the harmful deformations before they occur.
2Manufacturing precision
If post-welding machining is performed to correct flange deformations, then manufacturing precision is improved, but the process time and complexity increase
Solution Approach 1:
The patent eliminates the need for time-consuming post-welding machining by performing the alignment correction in advance. The tooling is mounted before welding and maintains the flanges in the correct positions throughout the welding process, so that when the tooling is removed, the flanges are already properly aligned and no additional machining is required.
3Reliability
If a non-compliant vane needs replacement, then reliability is improved, but the flange cannot undergo further machining operations
Solution Approach 1:
The patent applies preliminary action by performing the flange alignment and positioning before welding, so that the flange maintains its original shape and machining surfaces intact. This allows compliant vanes to be replaced without requiring additional post-welding machining operations, as the flange is already in the correct position and condition to receive new vanes.
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 effectively minimizes the impact of shrinkage phenomena during welding, allowing for efficient and economical manufacturing of turbomachine bladed elements by maintaining the original shape and position of the flanges and ferrule, reducing the need for extensive post-welding machining.
Implementation Method 1
The forces exerted on the flanges by the tool are intended to elastically deform at least one of the flanges and the ferrule so that the displacements thus obtained compensate for the constrictions which will be exerted during welding.
Data Source
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AI summary
A method for manufacturing a bladed stator element (10) for a turbomachine, particularly for aircraft, this bladed element having a general annular shape around an axis and comprising an annular ferrule (12) extending around the axis and having an annular mounting flange (14, 16) extending radially outwards at each of its axial ends, and an annular row of blades (18) extending around the axis inside the ferrule and whose radially external ends are fixed to the ferrule, the method comprising steps of welding the radially external ends of the blades to the ferrule e, characterized in that it comprises: i) before welding one or more blade(s) in a circumferential area (Z) of the ferrule, a step of mounting a tool (26) on this area of the ferrule, between the flanges of the ferrule,this tooling being axially clamped against these flanges so as to exert tensile forces in opposite axial directions on these flanges, and ii) after welding this or these blade(s), a tooling dismantling step.