What is the disadvantage of Poldi hardness test?

What is the disadvantage of Poldi hardness test? Explanation: When the apparatus is not held perpendicular to the surface, it gives an error in the result. It is easily portable. It is cheap and can be performed on heavy machinery.

What is the disadvantage of the Rockwell hardness method?

The Rockwell method has the following disadvantages: It is not always the most accurate hardness testing method, as even a slight error in measuring the depth difference can result in a significant error in the calculated hardness value.

What is the tolerance for Rockwell hardness?

For SPC to work effectively, the com- bined variation should be less than 10\% of the process tolerance (<10\% GR&R). Rockwell hardness testing machines with a GR&R be- tween 10 and 30\% may be acceptable on an in- terim basis; machines with a GR&R of greater than 30\% should not be used for SPC.

What is the limitation on the thickness of specimens for a hardness test explain?

The limitation is too thin, if an indentation is made too near a specimen edge or if twoindentations are made too close to one another.

What are the advantages of using the hardness test?

The application of hardness testing enables you to evaluate a material’s properties, such as strength, ductility and wear resistance, and so helps you determine whether a material or material treatment is suitable for the purpose you require.

Why is hardness important?

Hardness is the property of a material that enables it to resist plastic deformation, penetration, indentation, and scratching. Therefore, hardness is important from an engineering standpoint because resistance to wear by either friction or erosion by steam, oil, and water generally increases with hardness.

How Rockwell hardness is calculated?

The Rockwell hardness (HR) is calculated by measuring the depth of an indent after an indenter has been forced into the specimen material at a given load.