This part of ISO 148 covers the verification of pendulum impact mechanisms with regard to their individual parts, their overall impact work and the accuracy of the results obtained. It applies to pendulum impact mechanisms with 2 mm hammers or with 8 mm hammers that are used for notched-bar impact tests, for example according to ISO 148-1. This part of ISO 148 can be applied to pendulum impact mechanisms with different working capacities and different designs. Pendulum impactors used for testing metallic materials in accordance with this part of ISO 148 for operational, general or research purposes are referred to as operational pendulum impactors. Pendulum impact mechanisms for which more stringent requirements apply are referred to as reference pendulum impact mechanisms. Specifications for checking reference pendulum impact mechanisms are contained in ISO 148-3. This part of ISO 148 describes two verification procedures. a) The direct method, which is static in nature, involves measuring the critical parts of the pendulum impact mechanism to ensure that the requirements of this part of ISO 148 are met. The devices used for checking and calibration are based on national or international standards. b) The indirect method, which is dynamic in nature, uses reference samples to check the different points of the impact energy dissipated measurement scale. The requirements for the reference samples are contained in ISO 148-3. A pendulum impactor does not comply with this part of ISO 148 until verifications have been carried out using both the direct and indirect methods and the pendulum impactor meets the requirements set out in Sections 6 and 7. This part of ISO 148 describes how to evaluate the various components of the total impact energy consumed (absorbed) to fracture a sample. The total impact energy consumed consists of the energy required to break the sample and the internal energy losses of the pendulum impact mechanism after the pendulum has been released from its initial position and has completed the first half-oscillation. NOTE The internal energy losses are due to the following points: air resistance, friction in the bearing of the axis of rotation and the pointer of the pendulum, which can be determined by the direct method; Vibrations of the foundation, vibrations of the machine frame and the pendulum, for which no suitable measuring methods and measuring devices have been developed.
EN ISO 148-2:2016 Referenced Document
ISO 148-1:2009 Metallic materials - Charpy pendulum impact test - Part 1: Test method
ISO 148-3:2008 Metallic materials - Charpy pendulum impact test - Part 3: Preparation and characterization of Charpy V-notch test pieces for indirect verification of pendulum impact machines
ISO/IEC Guide 98-3:2008 Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in measurement (GUM:1995)
EN ISO 148-2:2016 history
2016EN ISO 148-2:2016 Metallic materials - Charpy pendulum impact test - Part 2: Verification of testing machines (ISO 148-2:2016)
2008EN ISO 148-2:2008 Metallic materials - Charpy pendulum impact test - Part 2: Verification of testing machines