What are the mechanical testing metals

MECHANICAL TESTING OF METALS 

1. Hardness Testing -

1. Hardness - The resistance of a metal to plastic deformation ,usually by indentation 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 test such as Rockwell, Brinell and Vickers .

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

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

3. Rockwell Hardness Test. An indentation hardness test using calibrated machines to force a diamond cone indenter or a hard steel ball under specified conditions into the surface of the material under test in two operations (preliminary and total loads) and to measure the depth of the impression under the specified load condition.

4. Brinell Hardness Test - An indentation hardness test using calibrated machines to force
a hard steel ball, under specified conditions of load and time, into the surface of the material under test and to measure the diameter of the resultmg impression after release of the load.

5. Vickers Hardness test - An indentation 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.

6. Rockwell Superficial Hardness Test. This test is similar to Rockwell hardness test where the minor and major loads are much smaller in value. One point of hardness of regular Rockwell corresponds to 2 microns, while in superficial, it corresponds to 1 micron.

7, Knoop Hardness Test. An indentation hardness test using calibrated machines to force
into the surface of the material under test, a rhombic based diamond-pyramid indenter of specified edge angles, under stipulated conditions and to measure the long diagonal after removal of the load .











This article was taken by (dr. sadhu singh )