Fracture and tensile properties of ASTM cross-comparison exercise A 533B steel by small punch testing

The small punch (miniature disk bend) test was used to estimate conventional tensile and fracture properties of the reactor pressure vessel A 533B plate steel provided by ASTM for its Cross-Comparison Exercise on Determination of Material Properties Through the Use of Miniature Mechanical Testing Techniques. The test procedures followed those developed over the last six years mainly through support of the Electric Power Research Institute. The small punch, disk-shaped specimen of 6.35 mm (0.25 in.) diameter and 0.5 mm (0.020 in.) thickness is loaded by a 2.54 mm (0.1 in.) diameter hemispherical head punch at a constant displacement rate of typically 0.25 mm (0.01 in.) per minute. The room-temperature material fracture toughness (K-lc) and uniaxial tensile stress-strain curve and properties estimated from three separate small punch tests at room temperature show good reproducibility and agreement with the conventionally-measured, large specimen values. A series of small punch tests exhibited well-defined temperature-dependent energy transition behavior and potential for estimation of standard Charpy transition temperatures from such data.