Residual Stress X-Ray Reference Piece via Surface Nanocrystallization
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Solution Overview
Problem
Existing methods for X-ray measurement of residual stress rely on strain-free iron powder as a reference piece, limiting the applicability to materials other than pure iron, such as spring materials and steel used in industrial settings.
Innovation Solution
A method involving nanocrystallization of a metal material's surface followed by annealing to eliminate stress, using shot peening to cancel orientation and leave only crystal grains capable of withstanding X-ray measurement, with nanocrystals present on the surface up to 50 μm deep.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If strain-free iron powder is used as a reference piece, then measurement reliability is ensured, but material versatility is limited
Solution Approach 1:
The invention changes the microstructural parameters of metal materials through nanocrystallization treatment, transforming the crystal grain structure to a nanometer scale. This parameter change enables various metal materials (not just iron powder) to achieve stress-free states suitable for X-ray measurement reference pieces, thus improving material versatility while maintaining measurement reliability
Solution Approach 2:
The invention makes the reference piece applicable to multiple metal materials through nanocrystallization treatment. By creating a universal nanocrystalline structure that can be applied to different metal types (iron-based, non-iron-based, alloys), the reference piece achieves multi-functionality across various material systems while maintaining consistent measurement standards
2Manufacturing precision
If nanocrystallization is performed by shot peening, then crystal grain refinement is achieved, but manufacturing complexity increases
Solution Approach 1:
The invention replaces complex chemical or thermal nanocrystallization methods with mechanical shot peening treatment. This mechanical approach achieves nanocrystalline structure through impact-induced plastic deformation and dynamic recrystallization, simplifying the manufacturing process while achieving the desired crystal grain refinement
Solution Approach 2:
The invention changes the manufacturing approach by applying specific shot peening parameters (shot size, velocity, coverage, number of passes) to achieve nanocrystallization. By optimizing these physical parameters, the process achieves precise crystal grain control without requiring complex equipment or multi-step procedures
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 the use of metal materials other than strain-free iron powder as reliable reference pieces for X-ray measurement of residual stress, ensuring accurate and stress-free measurement results.
Implementation Method 1
the nanocrystallization is performed by shot peening
Implementation Method 2
after at least a portion of a surface of a metal material has been nanocrystallized
Implementation Method 3
stress being eliminated by annealing the same
Implementation Method 4
X-ray measurement of residual stress
Data Source
AI summary
A metal material other than strain-free iron powder can be used as a reference piece for X-ray measurement of residual stress. The metal material is manufactured by nanocrystallizing at least a portion of a surface of a metal material, and then removing inherent strain by annealing the metal material, thereby eliminating stress.