Determination of the minimum quantity of irradiated ferritic steel specimens for small punch DBTT testing

The small punch (SP) creep test was carried out at the temperatures of 823∼923 K by using a further miniaturized specimen, namely, TEM disk-type specimen (φ 3.0×t0.25 mm). The tests were applied to the fine grain heat affected zone (FGHAZ), tempered HAZ (THAZ) and base metal (BM), respectively, which were removed from the joint of the reduced activation ferritic steel welded by an electron beam welding, in order to investigate the creep properties of such local regimes. The results obtained from the SP creep test were correlated with those of uniaxial creep tests using the base metal (BM) and welded joint (WJ). Experimental results revealed that there were no large differences between the SP creep rupture strengths of the FGHAZ and THAZ and that of the BM at the relatively high load levels. This result was in good agreement with the fact that the uniaxial creep strength of the WJ was almost coincident with that of the BM at the relatively high stress levels. In addition, the ratio of load (P) to stress (σ), which gave same rupture time, was calculated by using the creep rupture data of the BMs. As a result, the ratio was determined to be 0.43, resulting in the following equation; P = 0.43 σ.

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Estimation of Uniaxial Material Properties by Miniature Small Punch Testing to Support Post-Irradiation Examination of RPV Steels

Volume 6: Materials and Fabrication ◽

10.1115/pvp2020-21490 ◽

2020 ◽

Author(s):

Stefan Holmström ◽

Oliver Martin ◽

Theo Bakker ◽

Murthy Kolluri ◽

Matthias Bruchhausen

Keyword(s):

Chemical Compositions ◽

Test Technique ◽

Small Punch ◽

Uniaxial Test ◽

Heat Treated ◽

Pressure Vessel Steels ◽

Material State ◽

Damaged Materials ◽

Reactor Pressure

Abstract The small punch (SP) test technique is expected to become a more common tool for estimating tensile properties since the technique has been approved for standardization and will be published early 2020 as EN-10371. The testing technique is naturally of interest in the nuclear field due to the small amount of material needed for estimating the properties of both virgin and irradiation damaged materials. In the project STRUMAT-LTO, supported within the Sustainable Nuclear Energy Technology Platform (SNETP), there is intention to use both miniature uniaxial test specimen as well as miniature SP specimen to assess the influence of high fluence irradiation on mechanical properties of the samples of the joint NRG-JRC irradiation campaign LYRA-10. The alloys represented in the irradiation campaign are variations of VVER and PWR reactor pressure vessel steels with tailor made chemical compositions. Four of the PWR model steels are tested here with miniature uniaxial specimens using the SP technique at room temperature (RT) and 100°C in as-received material state and at RT for heat treated (450°C / 40 h) material. The SP samples were extracted from used KLST (miniature Charpy) specimens. The results of this test program are expected to provide the basis for the future development of material property determination of irradiated materials.

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Determination of Material Fracture Toughness by Circular Pre-Cracked Small Punch Test Specimens

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.795.165 ◽

2019 ◽

Vol 795 ◽

pp. 165-171

Author(s):

Wu Lin Wang ◽

Du Wei Wang ◽

Kai Shu Guan

Keyword(s):

Fracture Toughness ◽

Empirical Correlation ◽

Fracture Toughness Test ◽

J Integral ◽

Small Punch Test ◽

Small Punch ◽

Punch Test ◽

Determination Procedure ◽

Material Fracture

Fracture toughness empirical correlation between SPT(Small Punch Test) with non-crack sample and standard fracture toughness test has been established in recent years. In order to compensate the imperfection of empirical correlation, such as absence theoretical basis, poor repeatability and universality, in this paper, an O-type pre-cracked sample was adopted to evaluate fracture toughness. The mechanical model of the sample is in compliance with plane strain condition in the direction of crack propagation. In this paper a determination procedure was studied and established, and the J-integral of steel Q345R was calculated using the procedure.

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