Charpy Testing

U-Notch Impact Testing

ISO 148-1 U-Notch pendulum testing is the European standard equivalent to ASTM E23 Charpy Impact testing. Both specimens use 10mm x 10mm x 55 mm specimens. Where the 45° V notch is required in the ASTM specification, it is replaced by 2mm or 5mm deep U notch geometry in the ISO specification.The stress concentration is less severe and has been found to be similar to the rarely used ASTM E23 Keyhole specimen geometry. Older European publications identify shipbuilding specifications that referenced ASTM keyhole Charpy data. There is no known correlation between the U notch and V notch specimens due to the distinct differences in the stress concentrations.

U-Notch Pendulum Tests

SGS MSi maintains an ISO 148-2 calibrated Charpy impact. The tester is essentially identical to the ASTM E23 impact tester with the exception of the 2mm striker. This machine is the same type of machine maintained by SGS MSi as an analog backup tester to our 700 ft-lb digital machine tester). Charpy U-Notch test requests are for material that is being purchased for companies with European material specifications or for products that are intended for export to Europe.

Common nomenclature identifies the type of striker to be utilized, such as KU₂ or KU₈ which is identifying either a 2mmm or 8mm striker on the impact tester.  SGS MSi uses a 2mm striker on our impact tester that is calibrated to the requirements of ISO 148-2 (the 8mm is equal to the ASTM E23 striker).  Machines can not change strikers without recalibration. Discuss this requirement with your test laboratory on any ISO Charpy testing before submitting samples.

All U-notch specimens are machined with a 1mm diameter at the base of the notch. SGS MSi uses a diamond impregnated dressing stone with the 1mm notch geometry. This type of dressing stone ensures that we control the geometry and depth of all U-notches.

SGS MSi can perform testing U-notch testing at the following test temperatures:

+300°F to -150°F
-321°F (Liquid Nitrogen)
-452°F (Liquid Helium)

Test Methods

Contact a sales representative at SGS MSi to discuss your Charpy U Notch, ISO 148-1 notch testing requirements today.