Weld Cladding Over Openings Using Support Structure
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Solution Overview
Problem
Current methods for weld cladding over large openings in thin-walled structures, such as gas turbine blades, are tedious, expensive, and prone to material slumping or cracking, and often require the use of backing materials that can introduce stress risers or be difficult to remove.
Innovation Solution
A method using a supporting structure, such as a metal filament or grid, with optional supporting powder to span large openings, allowing weld material to be deposited and metallurgically bonded, and then removing the powder to form a stable cladding layer, effectively managing opening dimensions beyond the limitations of prior art.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large openings are filled with many smaller weld passes placed around the periphery, then the opening can be filled with filler metal, but the process is tedious, expensive, and subject to slumping of the weld material
Solution Approach 1:
A supporting structure acts as an intermediary element placed at the bottom of the opening to prevent weld material from slumping. This mediator provides temporary support during the cladding process, allowing efficient filling of large openings without the tedious multiple-pass approach while maintaining structural integrity.
Solution Approach 2:
The supporting structure is installed before the cladding process begins, preparing the opening in advance to receive weld material without slumping. This preliminary action enables the entire opening to be filled in fewer passes, significantly improving productivity while ensuring reliable structural restoration.
2Reliability
If backing material such as ceramics or matching alloy plates is used to bridge large openings, then the opening can be supported, but backing plates create stress risers and add undesirable mass
Solution Approach 1:
The supporting arrangement provides localized support only where needed - at the bottom of the opening - rather than requiring full backing plates across the entire component. This localised approach prevents stress risers and minimizes added mass while maintaining opening support stability.
Solution Approach 2:
The supporting structure is designed to be temporary and removable after the cladding process completes. Unlike permanent backing plates that remain and create stress risers, this supporting arrangement is discarded after serving its purpose, eliminating unwanted mass and stress concentration points.
3Reliability
If solid preformed repair material is custom fit and welded into the opening, then the opening can be refilled, but the process is tedious, expensive, and may induce cracking as the material shrinks from welding
Solution Approach 1:
The supporting structure serves as a mediator that enables direct welding of filler material into the opening without requiring custom-fitted preformed pieces. This intermediary support prevents slumping during the simplified pouring/filling process, eliminating the tedious custom-fitting step while maintaining structural integrity.
Solution Approach 2:
The supporting arrangement is installed in advance to prepare the opening for simplified filler material placement. This preliminary support enables the use of simpler filling methods rather than requiring precise custom-fitted preforms, significantly easing the manufacturing process while preventing cracking through proper support.
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
Enables reliable and efficient cladding of openings up to 20 millimeters and larger, preventing slumping and ensuring structural integrity without the need for backing materials, while allowing for additive manufacturing processes.
Implementation Method 1
surface tension of molten metal to the adjoining substrate is adequate to prevent molten metal drop through due to gravity
Implementation Method 2
weld material is deposited over the supporting arrangement and processed into a cladding layer that is metallurgically bonded to the support structure
Data Source
AI summary
A method including spanning a relatively larger opening (50) with a support structure (72) to divide the larger opening into a plurality of relatively smaller openings (78); placing superalloy powder across the smaller openings and in contact with the support structure; and melting the superalloy powder to form a cladding layer (104) that spans the opening and is metallurgically bonded to the support structure.