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Charpy Impact Strength - ISO 179

Energy per unit area required to break a test specimen under flexural impact. Test specimen is held as a simply supported beam and is impacted by a swinging pendulum. The energy lost by the pendulum is equated with the energy absorbed by the test specimen.


Edgewise Impact


Flatwise Impact

Testing is performed on either notched or unnotched specimens. The impact blow is in either the edgewise or the flatwise direction for most materials. For long fiber reinforced specimens the impact is either normal or parallel to the orientation of the fibers. Type 2 and 3 specimens are used for long fiber reinforced materials.

Charpy Specimen Types
Type Length (mm) Width (mm) Thickness (mm) Span (mm)
1 80 10 4 62
2 25 x Thickness 10 or 15 3 20 x Thickness
3 11 or 13 x Thickness 10 or 15 3 6 or 8 x Thickness

Three different notch types may be used. Notch Type A is preferred.

Charpy Notch Types
Notch Notch Base Radius (mm)
A 0.25
B 1.00
C 0.10

ISO 10350 Note

ISO 10350 requires using a Type 1 specimen and an edgewise blow direction at either 23°C or -30°C for both notched and unnotched tests. For notched tests, Notch A is required.

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