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Fatigue Life Assessment of High-Strength Stainless Steels via Small Punch Testing
Ran Li1,2,3,4, Wenbo Li1, Wenshu Wei2,3
1Graduate School, China Coal Research Institute, Beijing 100013, China.
Materials (Basel, Switzerland)
|June 12, 2026
Summary
Small punch fatigue tests (SPFTs) on high-strength stainless steels revealed distinct fatigue stages and power-law relationships. A critical strain energy density (SED) criterion effectively assessed fatigue life, with PH13-8Mo showing the highest SED values.
Area of Science:
- Materials Science
- Mechanical Engineering
- Metallurgy
Background:
- High-strength stainless steels are crucial in demanding applications.
- Understanding their fatigue behavior under complex loading is essential.
- Small punch fatigue tests (SPFTs) offer a method for evaluating material fatigue properties.
Purpose of the Study:
- To investigate the fatigue behavior of three high-strength stainless steels (X17CrNi15-2, 15-5PH, PH13-8Mo) using SPFTs.
- To establish relationships between fatigue life and key mechanical parameters.
- To assess the applicability of a strain energy density (SED) criterion for fatigue life prediction.
Main Methods:
- Conducting small punch fatigue tests (SPFTs) on selected stainless steel specimens.
- Analyzing SPFT valley displacement versus SPFT life curves to identify fatigue stages.
- Characterizing fracture mechanisms using scanning electron microscopy (SEM).
- Performing finite element analyses (FEA) to determine local stresses and strains.
- Applying a simplified critical strain energy density (SED) criterion for fatigue life assessment.
Main Results:
- SPFT curves exhibited three distinct stages for all tested steels.
- Power-law relationships were established between maximum forces and SPFT lives.
- Fracture mechanisms varied with material type and applied load.
- FEA-derived strain energy density correlated well with SPFT life.
- The order of SED values for fatigue life was PH13-8Mo > 15-5PH > X17CrNi15-2.
Conclusions:
- The study successfully characterized the fatigue behavior of three high-strength stainless steels using SPFTs.
- A critical SED criterion provides a viable approach for predicting SPFT life.
- Material-specific SED values offer insights into relative fatigue resistance, with PH13-8Mo demonstrating superior performance.
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