Linear Friction Welded Bladed Disk for Cold-Dwell Fatigue Life

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Solution Overview

Problem

Welded shaped bodies, such as bladed disks, experience a significant reduction in cold-dwell fatigue life due to non-uniformity in material structure, particularly when formed from large-sized forged or rolled materials, leading to a shorter actual product life than predicted by cyclic fatigue properties.

Innovation Solution

The use of linear friction welding to create a welded shaped body with structure-controlled materials, ensuring a homogeneous material structure, particularly in the first blade part, which is produced from small-sized forged or rolled materials, and controlled through adjustments in rolling reduction ratios and welding pressures to enhance cold-dwell fatigue life.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of substance

If products are produced by cutting out from large-sized forged materials, then the mechanical properties are maintained, but material waste occurs in the rough working stage

Engineering Contradiction:
Improvematerial wasteVSAvoidrough working process
Core Design Contradiction:
Loss of substanceVSEase of manufacture

Solution Approach 1:

The invention divides the product into multiple welding target members with homogeneous material structures, welding them together to form the final shaped body. This segmentation allows each member to be manufactured separately with controlled material structure, eliminating the need to cut from large forged blocks and reducing material waste while maintaining mechanical properties.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention creates a composite structure by welding multiple members with specific homogeneous material structures together. The welded shaped body combines multiple homogeneous material structures to achieve the desired form while maintaining overall mechanical properties and cold-dwell fatigue resistance, avoiding material waste from traditional cutting methods.

Inventive Principle:
Principle #40Composite materials

2Ease of manufacture

If welding is performed on members with non-uniform material structure, then the manufacturing process is simplified, but cold-dwell fatigue life is significantly reduced

Engineering Contradiction:
Improvewelding processVSAvoidcold-dwell fatigue life
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention requires that each welding target member have a homogeneous material structure locally, even though the overall product is assembled from multiple members. This local homogeneity in each welded member ensures that cold-dwell fatigue life is not significantly reduced, while still allowing manufacturing flexibility through the welding process.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention controls the material structure parameters of the welding target members to ensure homogeneity. By adjusting manufacturing parameters such as rolling reduction ratios and welding pressures, the invention achieves homogeneous material structures in each member, thereby maintaining cold-dwell fatigue life while enabling the welding manufacturing process.

Inventive Principle:
Principle #35Parameter changes

3Loss of substance

If linear friction welding is used to form the welded shaped body, then material waste is reduced, but the material structure uniformity must be precisely controlled

Engineering Contradiction:
Improvematerial wasteVSAvoidmaterial structure uniformity
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The invention precisely controls manufacturing parameters including rolling reduction ratios and welding pressures during linear friction welding to achieve homogeneous material structures in each welding target member. This parameter control ensures material structure uniformity is maintained while still allowing the material-efficient welding process to be used.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention implements control mechanisms to monitor and adjust the material structure formation during the linear friction welding process. By using feedback control on parameters such as welding pressure and rolling reduction ratio, the invention ensures homogeneous material structures are achieved in each welding target member, maintaining manufacturing precision while reducing material waste.

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 significantly prolongs the cold-dwell fatigue life of the welded shaped body by maintaining a uniform material structure, reducing the likelihood of life shortening, and enhancing fatigue resistance properties, especially in titanium alloys.

Implementation Method 1

a friction welding step of bringing the second surface into contact with the first surface and welding the second welding target base member to the first welding target base member by linear friction welding

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4582212A1Bonded shaped body, and method for manufacturing same
Publication Date: 2025.07.09 OSAKA UNIVERSITY
  • EP4582212A1 patent drawingFigure 1~2
  • EP4582212A1 patent drawingFigure 3
  • EP4582212A1 patent drawingFigure 4

AI summary

A welded shaped body (1) includes a disk part (10) and a first blade part (20) that is welded to the disk part (10) by linear friction welding. A structure that is integrally formed by being cut out from one solid block (100) made of a material of a type identical to a type of a material of the first blade part (20) and that has a shape identical to a shape of the welded shaped body (1) is referred to as a comparative structure (101). The first blade part (20) has a material structure that is homogeneous and that exhibits a cold-dwell fatigue life longer than a cold-dwell fatigue life of the comparative structure (101).