ISO 148-2 — Verification of Charpy pendulum impact testing machines

ISO 148-2 · ISO standard

ISO 148-2 specifies how to verify pendulum impact testing machines used for Charpy testing of metallic materials. It confirms that a machine measures absorbed energy accurately, which is what makes impact-toughness results comparable. To verify a Charpy machine or add one to your lab, talk with our team.

What ISO 148-2 Covers

The standard checks the machine itself rather than the Charpy test: pendulum geometry, friction and windage losses, striker and anvil dimensions, and the energy-indicating system. Both a direct check of the machine and an indirect check using reference test pieces are used to confirm performance.

Why It Matters

Charpy results drive decisions on toughness and ductile-to-brittle behaviour, so an inaccurate machine can pass or fail material incorrectly. A current ISO 148-2 verification is the record that keeps impact data defensible.

Reading the Designation

Cited as ISO 148-2:YYYY. Confirm the edition before setting verification intervals and acceptance limits.

Direct and Indirect Verification

Verification combines two approaches that support each other:

Direct: measurement of the physical parameters, such as pendulum dimensions, friction loss, and striker and anvil geometry.
Indirect: testing certified reference specimens and comparing the measured absorbed energy against their certified values.