Hole Surface Compression Using Media-Filled Residual Stress Processing
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Solution Overview
Problem
Existing methods for applying compressive residual stress to the inner surfaces of holes in metal parts with complex shapes are inefficient, as they require specialized nozzles or tools that struggle to insert into and uniformly process such shapes, leading to difficulties in preventing stress corrosion cracking and damage.
Innovation Solution
A processing method and apparatus that fill the hole with processing media and apply an external force using a pressing member and hammer to uniformly apply compressive residual stress to the inner surface, regardless of the hole's shape, by inserting a pressing member into the hole and applying a load through the hammer, which is transmitted via the media to the inner surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a special nozzle is used to insert into a water cooling hole with a complicated shape, then shot peening can be performed on the inner surface, but the device complexity increases and it becomes difficult to uniformly process the inner surface
Solution Approach 1:
The patent introduces processing media (shot peening media) as an intermediary substance that fills the complicated-shaped hole and transmits the peening action uniformly to the inner surface. Instead of using a complex specialized nozzle to reach difficult geometries, the media particles themselves navigate the complex shape while the pressing member applies force to the media, which then distributes the compressive stress uniformly throughout the hole's inner surface regardless of its complicated geometry
2Reliability
If a linear burnishing tool is used to process a machined hole with a complicated shape, then compressive residual stress can be applied to the inner surface, but the tool cannot be inserted into the hole and uniform processing becomes difficult
Solution Approach 1:
The processing media serves as an intermediary that enables the pressing member to apply compressive residual stress to complicated-shaped holes without requiring the tool itself to conform to the complex geometry. The media fills the hole and transmits the pressing force uniformly to the inner surface, allowing the pressing member to have a simple structure that can easily be inserted into any hole shape
Solution Approach 2:
The patent changes the state of the processing media from a passive material to an active force-transmitting medium by applying external force through the pressing member. This parameter change (from static to dynamically pressurized) enables the media to uniformly distribute compressive stress throughout the complicated-shaped hole's inner surface
3Strength
If shot peening is performed by injecting shot media through a nozzle into a water cooling hole, then compressive residual stress is applied to the inner surface, but specialized nozzles are required for complicated shapes increasing device complexity
Solution Approach 1:
The processing media acts as an intermediary between the pressing member and the hole inner surface. Instead of requiring specialized nozzles to deliver shot media to complicated geometries, the pressing member simply compresses the media which then uniformly distributes itself throughout the hole, eliminating the need for complex nozzle design while maintaining fatigue strength improvement
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 applies compressive residual stress uniformly to the inner surface of holes with complex shapes, enhancing fatigue strength and preventing stress corrosion cracking, while also allowing for the formation of a protective metal film to reduce corrosion.
Implementation Method 1
applying an external force to the processing media to apply a compressive residual stress to an inner surface of the hole
Data Source
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AI summary
A processing method according to one aspect incudes preparing a metal workpiece having a hole that opens to a surface thereof, filling the hole with processing media, and applying an external force to the processing media to apply a compressive residual stress to an inner surface of the hole.