Experiment No. 2
Charpy Impact Test
Shiva Yadav
Aerospace Engineering, 3rd Sem
(Dated: August 10, 2022)
This report is a summary of the experiment to determine the Toughness of materials known as
the Charpy Impact Testing Method.Toughness is the amount of energy per unit volume that
a material can absorb before fracturing. In this method,a sample of the material is kept freely on
two supports and impacted using the Pendulum Impact Testing Machine and the loss of energy is
measured.
I. INTRODUCTION
The Charpy impact test was invented in 1900 by
Georges Augustin Albert Charpy (1865–1945), and
it is regarded as one of the most commonly used
test to evaluate the relative toughness of a material
in a fast and economic way. The Charpy impact test
measures the energy absorbed by a standard notched
specimen while breaking under an impact load. This
test continues to be used as an economical quality
control method to determine the notch sensitivity
and impact toughness of engineering materials such
as metals, composites, ceramics, and polymers. The
standard Charpy impact test specimen is of dimen-
sion 55 mm ×10 mm ×10 mm, having a notch of
U-shape machined across one of the larger dimen-
sions. The Charpy impact test measures the en-
ergy absorbed by a standard notched specimen while
breaking under an impact load . This test consists
of striking a suitable specimen with a hammer on a
pendulum arm while the specimen is held securely at
each end. The hammer strikes opposite the notch.
The energy absorbed by the specimen is determined
precisely by measuring the decrease in motion of the
pendulum arm .
II. THEORY
Charpy Impact Test is done to measure the tough-
ness of a material.Toughness is an important prop-
erty of a material defined as the capacity of a ma-
terial to absorb an amount of energy while being
plastically deformed before being fractured. This
toughness property of a material is associated with
both properties ductility and strength of the mate-
rial. In this test the given specimen is not fractured
completely because it requires more energy to frac-
ture this in ductile manner. If a material is frac-
tured after absorbing less amount of energy then it
has more brittle property and correspondingly is less
toughness material. A material with high toughness
Figure 1. Working of the Test
can withstand sudden high load. In the ductile frac-
ture,massive amount of energy is required and slower
propagation before fracture occures as compared to
brittle fracture. The ductile fracture also depends
on the crack formation.
III. EQUIPMENTS,MATERIALS USED
A. The Specimen
The specimen used in this experiment is made of
mild steel. Mild steel has a carbon content of (0.16
- 0.29)wt% and it is known for its low cost and ease
of forming .However,it has low tensile strength .
B. The Charpy Impact testing Machine
The specifications of the machine used are given
in table I. In this machine, a pendulum located at
a specific angle is released and it comes down and
strikes the specimen placed on anvils. The Specimen
has a U-notch shape where the striker contained in
the pendulum will strike. The pointer shows energy
absorbed but many losses such as friction must be
considered.
