Resilience tests on metals: Easydur precision according to ISO 148-1

Resilience is one of the most significant mechanical properties used to assess a material’s ability to withstand impact. In metallurgy and mechanical engineering, Charpy impact tests are the most common method for measuring the energy absorbed by a specimen during fracture. Standard ISO 148-1:2016 precisely defines how these tests must be carried out, ensuring reliable and comparable results.

From Georges Charpy to modern impact testing

The term “Charpy” comes from Georges Augustin Albert Charpy (1865–1945), a French engineer and metallurgist who, in the early 20th century, designed and standardized the impact pendulum for measuring metallic materials' toughness. His method, simple yet rigorous, remains the basis of one of the most important tests for mechanical characterization of metals.

ISO 148-1: the foundation for reliable results

ISO 148-1:2016 is the most recent version of the international standard governing Charpy impact tests on metallic materials. It precisely defines the test procedure, the specimens’ geometric parameters (V-notch or U-notch), and the criteria for measuring the energy absorbed during fracture.

The aim is to ensure consistency and repeatable results, regardless of the equipment or laboratory conducting the test. In production and quality control contexts, compliance with this standard is essential for obtaining reliable and internationally recognized data.

The Easydur Easy CP Charpy pendulum

The Easydur Easy CP Charpy pendulum is designed to perform high-energy resilience tests on high-strength steels and composite materials. Tests can be carried out at room temperature or at low temperatures (-20, -30, and -40 °C) to reproduce actual service conditions of materials exposed to brittle fractures.

Beyond resilience value measurement, examining the specimen after fracture allows further evaluations, such as measuring lateral expansion.

The system operates with Easydur software on Windows 10. Through a touch-screen PC and position encoder, it records the hammer’s rise angle and displays load values clearly and instantly.

A motorized arm with automatic locking ensures hammer lifting and resetting, allowing rapid execution of consecutive tests. Automatic friction calibration according to ASTM standards completes the process, ensuring accuracy and repeatability.

Technical features of the Easydur Easy CP Charpy pendulum

- Maximum available energy: 300 J / 500 J / 750 J
- Resolution: 0.10 Joule
- Suitable for specimens: Ku and Kv
- Machine dimensions: 800 × 578 × 1400 mm (W × D × H)
- Dimensions with protection: 2200 × 800 × 2300 mm (W × D × H)
- Weight: approx. 420 kg
- Power supply: 380 V / 50 Hz / 3-phase

Standards complied with

- ASTM E23 – Charpy impact test for sub-size specimens
- ASTM A370 – Standard test methods and definitions for mechanical testing of steel products
- ISO/TC 138/SC 5 – General properties of plastic pipes, fittings, valves, and accessories – Test methods and basic specifications
- UNI EN ISO 148-1 – Metallic materials – Charpy impact test – Part 1: Test method
- UNI EN ISO 10045 – Metallic materials – Charpy impact test – Test method

Operating principle of the Charpy pendulum

The pendulum’s operation is simple but requires a highly precise machine. The notched specimen (V or U) is positioned on the supports inside the pendulum frame. After the safety barriers are closed, the hammer, lifted automatically, is released.

The hammer strikes the specimen by gravity. Knowing the mass and the initial and rebound angles, the absorbed energy is calculated using the following formula:

K = m × g × l × (cos β – cos α)

The result provides the resilience value, i.e., the energy absorbed by the material before fracture, along with data on plastic deformation and fracture geometry:

Complementary tests

Charpy resilience tests are complemented by other Easydur mechanical tests, such as tensile and hardness testing (Brinell, Rockwell, Vickers).

For companies seeking complete characterization of their metallic materials, Easydur provides dedicated solutions and expert support through its contact channels.