ISO 148-3:2016

Overview

ISO 148-3:2016 - part 3 of the ISO 148 series - defines the requirements for preparing and characterizing Charpy V‑notch test pieces used for the indirect verification of pendulum impact testing machines. It specifies how reference test pieces (with nominal dimensions matching ISO 148‑1 but with more stringent tolerances) are produced, qualified and certified so they can be used to verify machine performance in accordance with ISO 148‑2.

Key topics and technical requirements

• Scope and purpose: Qualification of reference Charpy V‑notch test pieces for indirect verification of pendulum impact machines.
• Reference testing machines: Characteristics and verification requirements (geometrical characteristics, capacity, hardness, vibration, energy‑indicating mechanism) for machines used to assign certified values.
• Test piece specification: Material selection, heat treatment/chemical composition adjusted to target energy levels, dimensional tolerances and marking requirements.
• Batching and sets: Definitions and procedures for batches, characterization sets, reference sets, and how to select sets for machine verification.
• Certification and traceability: Assignment of a certified reference absorbed energy (K_R) with stated uncertainty and accompanying certificates, consistent with requirements for certified reference materials.
• Homogeneity and uncertainty: Procedures for assessing batch homogeneity and for calculating the uncertainty of the certified KV value (informative annex included).
• Normative references: Interactions with ISO 148‑1 (test method) and ISO 148‑2 (machine verification); references to guides such as ISO Guide 34 and GUM for uncertainty and CRM production.

Applications and users

ISO 148-3 is intended for organizations involved in:

• Calibration and verification laboratories that qualify pendulum impact machines using reference materials.
• Material producers, test-house operators and quality assurance teams who supply or accept metallic materials based on Charpy impact results.
• Manufacturers of impact testing machines and national metrology institutes that maintain reference machines and issue certified reference test pieces.
• Standards bodies and accreditation organizations responsible for conformity assessment and traceability of mechanical testing.

Practical benefits include improved inter‑machine agreement, traceable certification of reference pieces, and a documented basis for indirect verification when acceptance testing of materials depends on consistent Charpy results.

Related standards

• ISO 148‑1: Charpy pendulum impact test - Test method
• ISO 148‑2: Charpy pendulum impact test - Verification of testing machines
• EN 10045‑2 and ASTM E23 (other standards that require reference test pieces)
• ISO Guide 34 and GUM (for CRM production and uncertainty analysis)

Keywords: ISO 148-3, Charpy pendulum impact test, Charpy V‑notch, reference test pieces, indirect verification, pendulum impact machines, ISO 148‑2, certified reference material.