indentation+hardness+tests

=hardness= Hardness of materials can be quantified by various methods

Mohs scale
The Mohs scale of mineral hardness is based on the ability of one natural sample of matter to scratch another, from talc (1) to diamond (10). It does not represent absolute hardness as for example diamond (10) is four times harder than corundum (9) Using the following link to Mohs scale of mineral hardness.pdf Complete the following quiz =quiz - mohs hardness=

The most common method for measuring hardness for engineering materials is using:

=indentation hardness tests=

Indentation hardness relates directly to tensile strength. Consequently these tests can be used as a non-destructive method to accurately indicate tensile strength.

There are three standardised tests: (A.S. is short for Australian Standard) || =The Vickers hardness test= =A.S. 1817= || =The Rockwell Test= =A.S. 1815= (most widely used) ||
 * || =The Brinell hardness test A.S.1816=
 * Method || Indenter is a hardened steel ball || Indenter is a square based pyramidal diamond || Conical diamond and tempered steel ball ||
 * Advantages || It gives a linear scale and good for research || Rapid and accurate || Hardness value directly from gauge ||
 * Disadvantages || Cannot be used on thin metals. ||  ||   ||
 * Applications || Steel, cast iron, bronze etc, brass || Can be used for small thicknesses (to 0.15mm), steel tempered and untempered, case hardened || Steel tempered and untempered, cast iron bronze etc ||

All three tests can be performed using the:
 * ====GNEHM Universal Hardness Tester==== ||
 * [[image:GNEHM_Universal_Hardness_Tester.jpg width="570" height="963"]] ||

Let's look at some typical =hardness values=