Mechanical Properties Study of Miniature Steel Specimens Based on the Small Punch Test and Simulation Methods

The small punch test (SPT) can be very convenient to obtain mechanical properties due to its unique advantages from small-volume samples, and has gained wide popularity and appreciation among researchers. In this paper, the SPT test and finite element (FE) simulations were performed for three alloys, and the yield stresses (σ(YS)) and ultimate tensile strengths (σ(UTS)) from the uniaxial tensile test (UTT) were correlated with the yield force (F(y)) and maximum force (F(m)) of the small punch test (SPT) before and after compliance calibration. Finally, the effect of specimen size on the SPT curves was discussed. The results showed that the deviation between SPT test and FE simulation was due to the loading system stiffness, which was confirmed by the loading system compliance calibration test. The SPT curves before and after calibration have less influence on the empirical correlation results for σ(UTS), while the correlation results for σ(YS) depend on the method used to determine F(y) in the SPT curve. Finally, the simulation results indicated that the effect of specimen size on the force–displacement curve in the SPT is slight. This work also provides a reference for subsequent researchers to conduct empirical correlation studies using different specimen sizes.