During operation steel parts and structures are often subject to dynamic loads. It can exemplified by takeoff and landing of planes, high speed pressure metal treatment (at blacksmithing and press forming). In order to assess ability of steel materials withstand shock loads, “Center of industrial diagnostics and control” LLC performs dynamic tests that are widely applied also for revealing tendency of metals to brittle fracture.
Specific aspects of impact bending tests conducted by “Center of industrial diagnostics and control” LLC
At impact bending test the laboratory determines what force must be applied to destroy test sample. One of the most critical indicators is brittle fracture. Even small crack grows almost instantly, and main hazard of the brittle fracture is that it has no alarm signs. Accordingly at conducting impact bending test, it is important to determine behavior of metal at occurrence of cracks. Thus comprehensive tests of steel structures and welded joints are essential.
Clear standard technical documents for tests of steel structures and welded joints are developed in Ukraine.
Technological process of impact bending tests
Tests are conducted on pendulum impact testing machine. It is installed above sample and afterwards, as a results of pendulum impact testing machine falling, concussion with part takes place.
To simulate crack, notch in metal is made. It can have two shapes:
- U – Mesnager test piece has semiround shape. Its radius near basement = 1mm
- V – Charpy test piece with sharp notch. Its radius near basement makes up 0,25 mm
Type of notch and characteristics of the test piece are stipulated by regulatory documents. Tests result in determination of total energy of destructions. Test results except shape of the notch are affected by its size and temperature at which the tests are conducted.
“Center of industrial diagnostics and control” LLC performs impact bending test under laboratory conditions of the company using pendulum impact testing machine МК-30 at normal and subzero temperatures.