Notched bar impact test

The notched bar impact test is used to determine the toughness or notched bar impact strength of a metal sample under impact load. This test is usually carried out at room temperature or low temperatures. Determining the steep drop is particularly important for Crz metals, such as ferritic and pearlitic steels. This describes the sudden transition from tough to abruptly brittle fracture behavior at falling temperatures.

During the measurement, the potential impact energy (position energy) consumed when the sample is bent is determined. This is done using a rotation angle sensor and physical calculation.

What needs to be considered with this method and the samples?

Suitable samples:
Metallic solids with a minimum size of W × H × L = 10 × 10 × 55 mm.

Measuring range/options:
The exact measuring range depends on the material composition and the specific requirements of the desired temperature ranges. Especially at lower temperatures to determine susceptibility to brittle fracture.
Usual test temperatures -75°C to +200°C.
Temperature range can be extended to -196°C (liquid nitrogen) up to max. +300°C.

Specimen specifications:
Samples with V or U-notches. For statistical reasons, we recommend testing at least 3 samples per temperature to be tested (scattering values).

Optimum working range:
30 - 270 J (10 - 90% of the nominal working capacity).

Do the samples have to have a certain geometry?

Yes, the specimens must have a specific geometry and surface finish to meet the requirements of the impact test.
ISO 148-1 specifies the specimen shape precisely, usually with a V- or U-shaped notch. This specimen shape can either be produced by the customer or by us.

In the latter case, we take care of the feasibility evaluation, the optimum specimen removal (position of the specimen), the creation of the technical drawing and the production of the specimens according to the current standard by an external partner.

What results can be obtained from the notched bar impact test?

Notched impact energy (impact energy): The energy (in joules) required to break the sample at a given temperature.
Impact strength: Resistance of the material to impact load (in ^J/cm2).
Brittleness behavior: Graphical representation of the fracture behavior as a function of different application temperatures.

In addition, the following parameters can be evaluated at additional cost: