Hardness Testing Insight

Hardness Testing Insight

Write a short note on the hardness test.
Or
Describe briefly hardness. 
Or
Write a short note on hardness. 
Answer:

In mineralogy hardness to described as the ability of a material to resist scratching. In metallurgy and in most other fields, the resistance to indentations is called “hardness”.

In hardness tests, a small indenter is forced into the surface of the material to be tested under controlled conditions of load and rate of application. The depth or size of the indentation formed is measured. From this measurement, a hardness number is determined. Soft is the material, larger and deeper the indentation, and lower is the hardness index number.

Classification of Hardness Test:

•  Based on the method of application of the indenter:
  • Static loading
  • Dynamic loading
• Based on the size of the indenter:
  •  Micro indentation
  •  micro indentation
• Amount of load applied to indenter:
  • Macro hardness, i.e. more than 1 Kg load
  •  Microhardness, i.e. less than 1 Kg load
• Following are the hardness test viz:
  • Brinell hardness test
  •  Rockwell hardness test
  •  Knoop hardness test
  • Vicker’s hardness test
  •  Barcol hardness test
  •  Shore hardness test