Diffusion Alloy Insert Brazing for Superalloy Structural Repair

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Solution Overview

Problem

Hard-to-weld superalloy components in gas turbine machines face challenges in achieving sufficient mechanical strength due to difficulties in controlling the narrow brazing gap size, leading to inadequate repair methods that do not provide the necessary strength for operational conditions.

Innovation Solution

A method involving the fabrication of a diffusion alloy insert with a controlled narrow braze gap size, where a tapered slot is machined in the component, an insert with corresponding geometry is formed, a braze material layer is deposited and sintered, and the insert is positioned and brazed to join with the component, ensuring a strong structural repair.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If brazing is used to repair hard-to-weld superalloy components, then the components can be rejuvenated, but the mechanical strength is insufficient when the brazing gap size is not very narrow

Engineering Contradiction:
Improveservice life of componentVSAvoidmechanical strength of brazed joint
Core Design Contradiction:
Duration of action of stationary objectVSStrength

Solution Approach 1:

A tapered slot is machined into the component before brazing, and a corresponding tapered insert is prepared in advance. This preliminary geometric configuration ensures that when the insert is placed in the slot, it automatically creates and maintains a narrow braze gap throughout the brazing process, enabling strong mechanical joints while repairing the component

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A braze material layer is deposited on the insert surface as an intermediary substance. This braze material fills the narrow gap between the insert and the component, creating a strong metallurgical bond that provides the necessary mechanical strength for the repaired component to withstand operational loads

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If conventional brazing is used for repair, then the process is simple, but the brazing gap size cannot be controlled to the desired narrow dimension

Engineering Contradiction:
Improveease of repair processVSAvoidbrazing gap size control
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The repair process is segmented into distinct stages: machining a tapered slot with specific geometric dimensions, preparing a matching tapered insert, depositing braze material, and assembling. This segmentation allows each stage to be optimized independently, ensuring precise gap control while maintaining overall process simplicity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A tapered (asymmetric) geometry is used for both the slot and insert instead of parallel-sided configurations. The tapered shape naturally converges toward a narrow gap at the interface, providing automatic geometric control of the braze gap size without requiring complex adjustment mechanisms or high-precision assembly procedures

Inventive Principle:
Principle #4Asymmetry

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 provides a component with a tensile strength greater than 500 MPa at room temperature, effectively addressing the limitations of existing repair techniques by ensuring a controlled narrow braze gap size for enhanced mechanical strength.

Implementation Method 1

The layer of the braze material is sintered on the outer surface of the insert to fabricate a diffusion layer

Methodology Applied
Scientific EffectDiffusion: Diffusion

Implementation Method 2

the insert is positioned into the tapered slot and brazed to join the insert to the taper slot of the component

Methodology Applied
Scientific EffectBrazing: Brazing

Data Source

PatentEP3345718B1Structure braze repair of hard-to-weld superalloy components using diffusion alloy insert
Publication Date: 2022.03.23 GENERAL ELECTRIC CO
  • EP3345718B1 patent drawingFigure 1
  • EP3345718B1 patent drawingFigure 2
  • EP3345718B1 patent drawingFigure 3

AI summary

A method (100) for treating a component (201) and a treated component (201) are provided. The method (100) includes the steps of machining (101) a tapered slot (204) in the component (201). The tapered slot (204) is measured to determine dimensions. An insert (301) is formed to have a corresponding geometry to the tapered slot (204) with a braze gap (303) between an outer surface of the insert (301) and an inner surface of the tapered slot (204). A layer of a braze material is deposited on the outer surface of the insert (301), where a thickness of the layer corresponds to the braze gap (303). The layer of the braze material on the outer surface of the insert (301) is sintered to fabricate a diffusion layer (302). The insert (301) is positioned into the tapered slot (204). The diffusion layer (302) is brazed to join the insert (301) to the taper slot. The treated component (201) includes a surface having a tapered slot (204), an insert (301), and a braze joint.