Charpy V Notch Impact Testing
In this section:pressure vessel steel | boiler steel plate | ASTM A516 Grade 60 | ASME SA516 Grade 60 |
ASTM A516 Grade 65 | ASME SA516 Grade 65 | ASTM A516 Grade 70 | ASME SA516 Grade 70
charpy v notch impact testing | test certification
The test involves the use of a steel specimen measuring 55 x 10 x 10mm which is supported at both ends and subjected to a pendulum blow behind a machined notch which is either 'U' or 'V' in shape.
The energy absorbed in fracturing the specimen (measured in Joules) is calculated by the height to which the pendulum rises after breaking the test piece. The test itself can be carried out in a variety of temperatures to determine material performance at either increased or cryogenic temperatures.
For carbon steels at higher temperatures the test specimen will fracture by a ductile mechanism whilst at low temperature the fracture is of a brittle nature absorbing much less energy. Within the transition range between the two extremes both ductile and brittle fracture is observed.
The test results can be based around absorbed energy, lateral expansion, fracture appearance or a combination. The actual Charpy impact test can vary due to being subjected to specific standards.
Test Specimen and Testing Rig – Charactersitics
| Designation | Unit |
| Length of test piece | mm |
| Height of test piece | mm |
| Width of test piece | mm |
| Height below notch | mm |
| Angle of notch | Degree |
| Radius of curvature of base of notch | mm |
| Distance between anvils | mm |
| Radius of anvils | mm |
| Angle of taper of each anvil | Degree |
| Angle of taper of striker | Degree |
| Radius of curvature of striker | mm |
| Width of striker | mm |
| Energy absorbed by breakage KU or KV | Joule |
About Ductile to Brittle Transition
Notched bar impact testing of a specimen over a temperature range will show a change from ductile fracture at higher temperatures to brittle fracture at lower temperatures revealed by a drop in impact energy. This testing raises the important issues concerning the fracture toughness of steel which can change dramatically over a relatively small temperature range.Consideration should therefore be taken when using steel in particular working environmemts, especially ones where significant temperature variation is commonplace.
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Related articles: (click on a link below to view) | |||
| • Pressure Vessel Steel Overview | ||||
| • Boiler Steel - Overview | ||||
| • ASTM A516 Grade 60 / ASME SA516 Grade 60 | ||||
| • ASTM A516 Grade 65 / ASME SA516 Grade 65 | ||||
| • ASTM A516 Grade 70 / ASME SA516 Grade 70 | ||||
| • About Charpy V Notch Impact Testing | ||||
| • About EN10204 3.1 and 3.2 certification | ||||
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