onlinemetallurgy.com

2. For more help contact me
Muhammad Umair
Bukhari
Engr.umair.bukhari@gmail.com
http://onlinemetallurgy.com

3. What is hardness ?
Different fields have different concepts
In metallurgy “the resistance to indent
formation or penetration is called hardness”.

4. Why hardness testing?
It is done mainly for two reasons:
• For research purpose
• For application purpose

5. How to measure hardness?
There are some well known following
methods;
o Brinell hardness (HB)
o Rockwell hardness (HRC)
o Vicker hardness (HV)
o Ultrasonic hardness (UCI)
Note: there is no conversion of one scale to another.

6. Ultrasonic Hardness
• Basic principle:
In UCI material is indented by converting
electronic frequency into mechanic force and
the indentation area size is calculated as a
function of electronic frequency.

7. Process description
• It is the modified form of Vicker’s
hardness testing
• Ultrasonic frequency is converted
into mechanical force/vidration by
Piezo transducer
• And the frequency shift is
measured with Piezo reciever
• Material is indented with Vicker’s
oscillating diamond-tipped rod

8. Continue……
• Rod is oscillated at a particular frequency
• Material is indented with a constant force
• All the process completes in very short time

9. Continue….
• Vicker hardness equation
HV= F/A
above equation is modified for ultrasonic
frequency shift

10. Piezoelectric Material:
• A piezoelectric sensor is a device that uses the
piezoelectric effect to measure pressure,
acceleration, strain or force by converting
them to an electrical signal.