Investigation on the Tensile Properties of Inconel 625 Using Small Punch Test

Abstract

As a commonly used material in the petrochemical, nuclear and aerospace fields, Inconel 625 has excellent strength and corrosion resistance. The accurate evaluation of material properties with small specimen volume is of great significance to ensure in-service equipment safety. To realize reasonable estimations of tensile strength based on the small punch test, load–displacement and slope–displacement curves of Inconel 625 were discussed in this study. The results prove that the first inflexion point can be used in the yield strength analysis based on the empirical correlation method and plate bend theory. Meanwhile, the lowest point of the elastic and plastic deformation stages in the slope–displacement curves were compared. A new deformation energy method was established to realize yield strength estimations. To analyze the ultimate tensile strength, a small punch deformation feature was discussed based on the geometric deformation model and microstructure analysis. The relationship between stress and displacement was obtained. Fm/dmt0 was proven to be a more appropriate parameter in ultimate tensile strength estimations.

Keywords

• small punch test
• tensile properties
• Inconel 625
• empirical correlation
• deformation energy