Experiment No. 1
Brinell Hardness Test
Shiva Yadav
(Dated: August 10, 2022)
This report is a summary of the experiment to determine the Hardness of materials known as
the ”Brinell Hardness Testing Method”. In this method,a sample of the material is indented
using a Hardened Steel Ball Indenter of fixed diameter and indent diameter is obtained from which
the BHN is calculated as a measure of hardness of the material.
I. INTRODUCTION
The hardness of a material is its ability to with-
stand localized deformation such as abrasion, cut-
ting, etc. This property is of crucial importance es-
pecially when a metal is being worked, as harder ma-
terials are tricky and more expensive to work with
than a metal of relatively low hardness. The Brinell
hardness testing method, proposed by swedish en-
gineer Johan August Brinell in 1900 was the first
widely used hardness test in engineering. While the
large indentation size and the possibility of damage
to the test piece results in the test being of lim-
ited use, the BHN determined by the test could
be converted into the Ultimate tensile strength (the
relationship depends on the Material) which is a vi-
tal manufacturing specification for various applica-
tions.
II. THEORY
In Brinell testing machine the load is applied by a
lever mounted on knife edges and carrying a hanger
for suspending the required load . The supporting
table for spacing the specimen can be raised or low-
ered by a steel screw by operating a large hand wheel
. When testing, the load is applied and removed by
hydraulic power controlled by a hand lever.
The indenter used is a hardened steel ball which
will have a diameter of 10mm , 5mm,or 2.5mm.
The reading microscope has a 25-fold magnification .
The gap between successive graduations of the scale
is 0.5mm and a micrometer is arranged sideways, the
eye piece of the reading microscope of the ball can
be measured in two perpendicular directions. Brinell
testing often use a test load of 500kg for relatively
soft materials such as copper, aluminium alloys and
3000 kgf for harder material and 10 mm wide inden-
ter so that the resulting indentation average out of
most surface and sub-surface inconsistencies . After
the load is applied for a specific time ( usually 10 to
15sec for hard ferrous materials and about 30 sec for
soft ferrous materials ) the recovered indentation di-
ameter is measured in millimetre. This time period
is required to ensure that plastic flow of work metal
has ceased .
A well structured Brinell hardness number reveals
the test conditions . Hardened steel can not be
tested by a hardened steel ball because the ball will
get flattened and become permanently deformed.
The appreciable error in BHN occurs at indenta-
tion diameter less than 2.9mm and for softer mate-
rials inaccuracy is at diameter greater than 6mm.
On tests of extremely hard metals a tungsten car-
bide ball is substituted for the steel ball and a spe-
cial hardened and burnished steel ball called the
“Hulked” ball may be used up to 55HBN. Compared
to the other hardness test methods , the indenter
used in Brinell makes the deepest and widest inden-
tation , so that test averages the hardness over a
wider amount of materials which will accounts for
multiple grain structures and any irregularities in
the uniformity of the material . The Brinell hard-
ness number is defined as the ratio of test load to
the surface area of indentation.
III. EQUIPMENTS USED
A. B3000
The B3000 (see fig 1) is equipped with a hydraulic
power pack and control circuitry to facilitate seam-
less loading and unloading operation.
B. The Microscope
The microscope(see fig 2) is fitted with a built in
scale used for measuring indents and a light to help
with viewing of the indent,
IV. PROCEDURE
First of all , the material is selected , and then
depending on the material load (P) selection is done,
