Gas Turbine Platform Restoration with EDM Recess and Laser Deposition

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Solution Overview

Problem

Existing methods for repairing gas turbine blade and vane platforms, such as tungsten inert gas welding and laser cladding, face challenges like high heat affected zones, distortion, porosity, and lack of precision, limiting the effectiveness and repeatability of the repair process.

Innovation Solution

The method involves creating a specific recessed shape in the deteriorated zone using electro-discharging machining, followed by additive manufacturing with five-axis laser metal deposition, optimizing the rebuilding process by defining angles and fillet radii to enhance the rebuilding quality and minimize defects like porosity and cracks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If tungsten inert gas welding is used to repair the platform, then the deteriorated zone can be rebuilt, but a large heat affected zone is created leading to gross distortion and loss of structural integrity

Engineering Contradiction:
Improverepair capabilityVSAvoidstructural integrity
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The invention changes the thermal parameters of the welding process by using laser cladding instead of tungsten inert gas welding. The laser process concentrates heat in a small area with precise control over heat input, transforming the thermal field distribution to minimize the heat affected zone while maintaining repair capability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention replaces the conventional tungsten inert gas welding mechanical system with laser cladding technology. This substitution uses a focused laser beam to melt and deposit material with precise spatial and temporal control, eliminating the large heat affected zone and associated distortion problems of traditional welding.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Manufacturing precision

If laser cladding technology is used to rebuild the damaged area, then the platform can be restored to original shape, but a time consuming milling operation is required for preparation

Engineering Contradiction:
Improveplatform restoration qualityVSAvoidpreparation time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The invention performs preliminary preparation by creating a recessed zone with specific geometric characteristics (inclined planes and fillet radii) before laser cladding. This pre-shaping of the substrate optimizes the bonding surface and facilitates better material adhesion, reducing the need for extensive milling operations while ensuring high restoration quality.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention applies local quality by creating a recessed zone with specific geometric features (inclined planes at defined angles and fillet radii) only in the damaged area. This localized preparation provides optimal surface characteristics for laser cladding adhesion without requiring time-consuming preparation of the entire platform.

Inventive Principle:
Principle #3Local quality

3Adaptability or versatility

If manual preparation and repair are used, then flexibility is maintained, but precision and repeatability are compromised leading to defects like porosity or lack of fusion

Engineering Contradiction:
Improverepair flexibilityVSAvoidrepair quality
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention replaces manual preparation and repair operations with automated laser cladding technology. The laser system provides precise control over heat input, material deposition, and process parameters, eliminating the variability and defects associated with manual operations while maintaining adaptability through programmable control.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention implements feedback control in the laser cladding process to ensure consistent repair quality. By monitoring and adjusting process parameters in real-time, the system maintains precise control over material deposition and fusion, eliminating defects like porosity and lack of fusion that occur with manual methods.

Inventive Principle:
Principle #23Feedback

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 approach achieves high rebuilding quality, reduces thermal distortion, and increases the repairability of critical areas, providing a more precise and repeatable method that minimizes material removal and enhances the structural integrity of the repaired parts.

Implementation Method 1

removing the deteriorated zone by means of a electro discharging machining tool

Methodology Applied
Scientific EffectElectrical discharge machining: Electrical Discharge Machining

Implementation Method 2

rebuilding the removed zone by means of additive manufacturing technology, in particular by means of a five axes laser metal disposition technology

Methodology Applied
Scientific EffectLaser metal deposition: Laser

Data Source

PatentEP3594446B1Method of restoring a blade or vane platform
Publication Date: 2021.10.20 ANSALDO ENERGIA SPA
  • EP3594446B1 patent drawingFigure 1~2
  • EP3594446B1 patent drawingFigure 3~5
  • EP3594446B1 patent drawingFigure 6~9

AI summary

A method for restoring a blade or vane platform (19) of a gas turbine (1) assembly for power plant; the method comprising the steps of: a) providing a blade (12) or a vane of a gas turbine assembly for power plant; wherein the blade or vane comprises a platform having a edge deterioration zone; b) removing the deterioration zone by means of electro discharging machining technology (30); c) rebuilding the removed zone by means of additive manufacturing technology; wherein the step b) is configured to create a recessed plane (34) along the platform edge; the recessed plane being connected to the platform plane by an enter inclined plane (35) and an exit inclined plane (35) arranged opposed along the platform edge.