Hardness Tests

 Hardness defined: Hardness may be defined as the ability of a material to resist scratching, abrasion, cutting or penetration.

HARDNESS TESTS

✔ Hardness defined: Hardness may be defined as the ability of a material to resist scratching, abrasion, cutting or penetration. 

✔ The hardness test is performed on a material to know its resistance against indentation and abrasion.

1. Types of Hardness Tests

The three most commonly used hardness tests are :

1. Brinell hardness test,

2. Vickers hardness test, and

3. Rockwell hardness test.

2. Basic Common Principle

The three hardness tests have the same basic principle as below : 

The hardness is measured from an indentation produced in the component by applying a constant load on a specific indenter in contact with the surface of the component for a fixed time.

In other words, an indenter is pressed into the surface of the material by a slowly applied known load, and the extent of the resulting impression is measured mechanically or optically. A large impression for a given load and indenter indicates a soft material, and a small impression indicates a hard material.