Charpy impact tests
The laboratory is equipped with Charpy impact machine Amsler RKP 300 with digital registering of angle. There are exchangeable strikers of 2 mm and 8 mm radius which enables tests in full compliance with ISO and ASTM standards:
- ČSN ISO 148-1
- ASTM E23, ASTM A370
The standards specify the dimensions of the test specimens, adjustment of the test machine and test procedure. The laboratory is equipped for tempering a testing from -70 °C to + 200 °C and at physical temperature of liquid nitrogen -196 °C.
For some cases, the laboratory also refers to other special standards that specify the location and orientation of specimens. List of test procedures, for which the laboratory is accredited, see the Appendix to certificate of accreditation.
Also we have instrumented striker and adjustable speed of impact pendulum. This allows tu evaluate the progress of fracture, dynamic limits and characteristics corresponding to the physical nature of fracture.
The result of the impact tests is the energy absorbed by the broken specimen. All data are related to a standard specimen 10 x 10 mm with V-notch 2 mm, it means to area 8 x 10 mm.
ISO and ASTM standards specify sub-size specimens up to thickness 2,5 mm, but the results obtained on different sizes of specimens cannot be compared directly. Experimentally and theoretically was shown that smaller specimens give higher (more favorable) values. This fact can be solved:
- Lowering the test temperature than is required for standard size
- Determining coefficient that reduces (tightens) specified absorbed energy
The tightening of the test condition or the specified values should be relative to the original thickness of the product to be tested and to proportion of actual size and standard size of specimens.
When require impact tests it is necessary to specify test specimen and notch orientation and test temperature. The notch is oriented usually perpendicular to the surface. Test temperature may be at room temperature, eg. RT, or at defined temperature in °C. To specify the tests, dimensions and number of the test samples, we recommend contacting our specialists.