Hardness Measurement by Brinell Hardness testing Machine

This method of determining the hardness of a sample complete covers the procedure and calculation using Brinell hardness tenting machine. As the brinell hardness testing is simple to do and results in this operation tell us about the operations and the properties of the test sample.

Introduction:

Hardness is the measure of resistance to indentation or plastic deformation. The quality of a product is dependent of the hardness. Many other properties of a material also depend upon the hardness e.g. tensile strength, strength, ***. In this experiment hardness was measured by the “Brinell hardness testing machine”.

Dr. J. A. Brinell invented the Brinell test in Sweden in 1900. The oldest of the hardness test methods in common use today

Experimental Work:

There were three samples in the experiment which were indicated by “Sample A”, “Sample B” and “Sample C”. Sample C was provided to me for hardness measurement. The apparatus required for this experiment is given below;

• Brinell Hardness Testing Machine


• Low Power Microscope


• Sand paper ( If sample surface is not clean)


• Sample

Procedure:

The procedure of the experiment was involved following steps;

• The sample C was provided me to perform the hardness test; the first job was to clean the surface of the sample by sand paper.


• After cleaning the surface of specimen the, the sample was placed upon the table and its height was adjusted using the wheel.


• Required amount of load “300Kg” was placed on the hanger.


• Pressure release liver is closed if it is already open.


• After perfect placement of the sample, the oil was pumped by using the handle.


• By the use of handle, the load was adjusted.


• The amount of applied load can be seen on the dial gauge.


• When our required load was applied on the sample, the loads started to float. Now here the application of pressure by the use on handle was stopped.


• After waiting for 15 seconds, the pressure was released by pressure release liver.


• An indent was produced on the sample.


• Another indent was also produced so that we can accurate our value by taking the average.


• Diameters of both indents on the sample were measured by the use of low power microscope.


• After measuring the diameter following mathematical calculations are performed.

Calculations:

Diameter of first indent = = 5.45mm

Diameter of second indent = = 5.55mm

Average Diameter = d = = = 5.5mm

Now Brinell hardness No (BHN) =

=

Where

F = the imposed load in kg

D = the diameter of the spherical indenter in mm

d= average diameter of the resulting indenter impression in mm

Brinell Hardness No (BHN) =

=115.9

Brinell Hardness No (BHN) on the BHN Chart = 116