Pendulum pile driver - a device with which laboratory tests of materials for impact strength are carried out. The essence of the test is that the firing pin with a certain weight, rotating around a fixed axis, falls from a certain height onto the test specimen, after which it makes a reverse pendulum movement, which is fixed on a special scale. [one]
Pendulum test types
Classification of materials impact test:
- by type of deformation : bending , stretching , compression, torsion , shear;
- by load: ordinary (from 4 to 7 m / s), high-speed (from 100 to 300 m / s) and ultra-fast (more than 300 m / s);
- by the number of strokes: one or more repeated;
- according to the test conditions (temperature, etc.).
Charpy method for testing samples from metals and alloys
The Charpy test (English) is carried out on a sample of metal or alloy, lying on two supports. The impact of the pendulum on the specimen falls in the middle between the supports, if the test is performed on the notched specimen, the impact of the pendulum falls opposite the notch. The difference between the potential energies of the copra before and after the impact determines the full work of the pendulum on the destruction of the sample.
The ISO 179 method is divided into ISO 179 / 1C (notched specimen) and ISO 179 / 2D (notched specimen).
The Charpy method differs from the Izod test method for specimens (English) by the method of installing the test specimen.
Double-support bending tests of metals and alloys using the Izoda method
The Izoda test is recommended for determining the impact strength of notched polygonal specimens. This is the standard method for testing plastics . The obtained test results by the Izoda method are used as reference information for comparing the toughnesses of various materials.
The ISO 180 method is divided into ISO 180 / 1A (sample 80 x 10 x 4 mm. With a notch) and ISO 180 / 1O (inverted sample 80 x 10 x 4 mm. - without a notch).
Testing metal samples at low temperatures
Testing of metals is carried out in series under conditions of gradually decreasing temperature - experiments on impact bending are done before the transition of the sample to a brittle state. Such tests are not carried out on cast iron samples, cast aluminum and magnesium alloys, since these metals already exhibit tearing resistance even under static loads.
For a gradual decrease in temperature when testing samples, cooling mixtures are used: dry carbon dioxide (-70 C), liquid air (-183 C), liquid nitrogen (-195 C), liquid hydrogen (-252 C). The quality of the metal is determined by the minimum temperature of loss of impact strength material β the lower its critical temperature of brittleness, the higher the resistance to brittle fracture. [2]
Features
- The main characteristics of the pile drivers:
- Weight kg
- Overall dimensions, mm
- The speed of the pendulum at the moment of impact, m / s
- The largest supply of potential energy, J
- Maximum power, kW (power)
- Clearance between supports, mm
- Range of measurement of energy, J
Application
Pendulum drivers are used for test and control tests in research and educational institutions, enterprises and laboratories, departments of technical control of enterprises and the quality of products from non-metallic materials, etc.
See also
- Charpy Impact Test
Notes
Links
- GOST 10708-82 Pendulums. Specifications (as Amended by N 1, 2)
- Pendulum drivers and laws of development of technical systems
- Tests for impact bending and at low temperatures
- PENDULUM COPER FOR TESTING SAMPLES OF MATERIALS IN SHOCK LOAD
- STATE STANDARD OF THE UNION SSR PLASTICS Method for determining Charpy impact strength
- The method for determining the impact strength according to Izod GOST 19109-84
- TEST METHOD FOR SHOCK BEND AT REDUCED, ROOM AND RISE TEMPERATURES GOST 9454-78