Give a critical discussion on why hardness test needs to perform in engineering practice.

b) Discuss 2 possible source of errors (other than parallax error) and how it's can effect the result.

a) Hardness is a measure of the resistance of a material to permanent deformation (plastic) on its surface,

Hardness tests play an important role in material testing, quality control and component acceptance.

Hardness test are needed to be perform as a quality assurance procedure, to validate materials are according to the specific hardness required,

We depend on the data to verify the quality of the components to determine if a material has the necessary properties for its intended use.

Through the years, the establishment of increasingly productive and effective means of testing, has given way to new cutting-edge methods that perform and interpret hardness tests more effectively than ever. The result is a greater capacity and dependence on "letting the instrument do the work", contributing to substantial increases in performance and consistency and continuing to make hardness tests very useful in industrial and R&D applications.

b)

Instrumental errors: Instrument calibration is extremely important. An instrument with expired calibration may be generating erroneous data systematically. Enviromental error: An example is when surface preparation of the sample to be tested is poor, then the error can be presented when measuring the indentation on the sample to determine the hardness value.