AIM: -
To
determined impact strength of steel.
OBJECT: -
To determine the impact strength of steel by Izod impact Test
APPARATUS:
-
1.Impact testing machine
2. A steel specimen 75 mm X 10mm X 10mm
THEORY:-
An impact test signifies toughness of material that is ability of material to
absorb energy during plastic deformation. Static tension tests of unnotched specimens
do not always reveal the susceptibility of a metal to brittle fracture. This
important factor is determined by impact test. Toughness takes into account
both the strength and ductility of the material. Several engineering materials
have to withstand impact or suddenly applied loads while in service. Impact
strengths are generally lower as compared to strengths achieved under slowly
applied loads. Of all types of impact tests, the notch bar tests are most
extensively
used. Therefore, the impact test measures the energy necessary to fracture a
standard notch bar by applying an impulse load. The test measures the notch
toughness of material under shock loading. Values obtained from these tests are
not of much utility to design problems directly and are highly arbitrary. Still
it is important to note that it provides a good way of comparing toughness of
various materials or toughness of the same material under different condition.
This test can also be used to assess the ductile brittle transition temperature
of the material occurring due to lowering of temperature.
PROCEDURE:-
1. With the striking hammer (pendulum) in safe test position, firmly hold
the steel specimen in impact testing machine’s vice in such a way that the
notch face the hammer and is half inside and half above the top surface of the
vice.
2. Bring the striking hammer to its top most striking position unless it is
already there, and lock it at that position.
3. Bring indicator of the machine to zero, or follow the instructions of the
operating manual supplied with the machine.
4. Release the hammer. It will fall due to gravity and break the specimen
through its momentum, the total energy is not absorbed by the specimen. Then it
continues to swing. At its topmost height after breaking the specimen, the indicator
stops moving, while the pendulum falls back. Note the indicator at that topmost
final position.
5. Again bring back
the hammer to its idle position and back
OBSERVATION:-
1. Impact value of - Mild Steel ------------N-m
2. Impact value of - Brass ------------N-m
3. Impact value of
- Aluminum ------------N-m
RESULT:-
i. The energy absorbed for Mild Steel is found out to be Joules.
ii. The energy absorbed for Brass is found out to be Joules.
iii. . The energy
absorbed for Aluminum is found out to be Joules
ALSO READ----HARDNESS TEST ON MILD STEEL
