what is mechanical testing

 

MECHANICAL TESTING OF MEATERIAL 

Introduction - In order to determine the suitability of a metal under a given loading conditions .It is essential to know the mechanical properties of the metal under different types of loading .

Hardness testing

Hardness - The resistance of a metal to plastic deformation usually by indentations .However the term may also refer to stiffness ,or temper or to resistance to scratching ,abrasion or cutting .Indentation hardness may be measured by various hardness tests ,such as Rockwell ,Brinell and Vickers .

Indentation Hardness - A number related to the area or to the depth of the impression made by an indenter or fixed geometry under a known static load .

The indentation hardness has no quantitative meaning .except in terms of particular test in which the area and shape of the indenter ,the indenting load and other conditions of test are specified .

Rockwell Hardness test - An indentation hardness test using calibrated machines to forces a diamond cone indenter or a hard steel ball under specified conditions into the surface or the material under test in two operations and to measure the depth of the impression under the specified load conditions .

Brinell Hardness test -  An indentations hardness test using calibrated machines to forces a  hard steel ball , under specified conditons of load and time , into the surface of the material under test to measure the diameter of the resulting impression after release of the load .

Vickers Hardness test - An indentations hardness test using calibrated machines to force a square based diamond -pyramid indenter having specified face angles into surface of the specimen under a predetermined load and to measure the diagonals of the resulting impression after release of the load.

 

 

This artical was taken by SOM (Dr.sadhu Singh )