1)How do the Rockwell and Brinell tests actually measure hardness ? Give any appropriate sketches and formula. Are there any units involved ? Describe the procedure for teh Rockwell test, explaining the reason for the pre-load ?
2)What is the limitation on the thickness of specimens for a hardness test ? Calculate the minimum thickness for one specimen for the Rockwell and Brinell test ?
3)What are the limimtations for distance from specimen edge to indentation and distance between indentations ? Explain why these limitations exist in both cases.
4)What surface condition is necessary for Brinell, Rockwell and Vickers ?
5)Why is the mean pressure(stress) under the indentor much greater than the yield stress How much greater is it ?
6)What are the advantages of Vickers test aganist Brinell test ?