Standard Test Method for Impact Testing of Miniaturized Charpy V-Notch Specimens

Importancia y uso:

5.1 There are cases where it is impractical or impossible to prepare standard CVN specimens. MCVN specimens are an alternative approach for characterizing notched specimen impact behavior. Typical applications include MCVN specimens prepared from the broken halves of previously tested specimens, from thin product form material, or from material cut from in-service components.

5.2 This test method establishes the requirements for performing impact tests on MCVN specimens fabricated from metallic materials. Minimum requirements are given for measurement and recording equipment such that similar sensitivity and comparable measurements, as compared to standard CVN tests, are achieved. The user should be aware that the transition region temperature dependence data obtained from MCVN specimens are not directly comparable to those obtained from full-size standard Charpy V-notch specimens, and suitable correlation procedures have to be employed to obtain ductile-to-brittle transition temperature (DBTT) data equivalent to those obtained using CVN specimens. In all instances, correlations will shall be developed to relate upper shelf energy (USE) data from MCVN tests to CVN comparable energy levels. Application of MCVN test data to the evaluation of ferritic material behavior is the responsibility of the user of this test method. MCVN test data should not be used directly to determine the lowest allowable operating temperature for an in-service material. The data shall be interpreted within the framework of a fracture mechanics assessment.

5.3 While this test method treats the use of an instrumented striker as an option, the use of instrumentation in the impact test is recommended and is fully described in Test Method E2298. In order to establish the force-displacement diagram, it is necessary to measure the impact force as a function of time during contact of the striker with the specimen. The area under the force-displacement curve is a measure of instrumented absorbed energy.

Subcomité:

E28.07

Referida por:

E2298-24

Volúmen:

03.01

Número ICS:

77.040.10 (Mechanical testing of metals)

Palabras clave:

impact test; instrumented impact test; lateral expansion; miniaturized Charpy test; notched specimens; pendulum machine; shear fracture appearance;