Welding Inspection & Metallurgy API ICP Self Study Notes

Vickers hardness testing follows the Brinell principle as far as the hardness is
calculated from the ratio of load to area of an indentation as opposed to the
depth (the Rockwell principle).
Rockwell: Depth of an indentation
Vicker: Area of an indentation
In the Vickers hardness test, an indenter of a definite shape is pressed into the
work material, the load removed, and the diagonals of the resulting indentation
measured. The hardness number is calculated by dividing the load by the
surface area of the indentation. The indenter for the Vickers test is made of
diamond in the form of a square-based pyramid. The depth of indentation is
about one-seventh of the diagonal length. The Vickers hardness value is
preceded by the designation (HV). The Vickers hardness number is the same
as the diamond pyramid hardness number (DPH). In-service hardness testing
may involve the use of portable variations of the above-described methods.
Alternatively, varying techniques based on rebound, indentation resistance or
comparator indentations may be applied and the results related to the hardness
scales more commonly accepted. Whatever technique is employed may well be
acceptable as long as it produces verifiable and consistent results.