Finding the K Value for AL Project Scale

[Steel_City82]

Im doing a project and i did some test with AL using the Rockwell/Vickers machine and I was wondering if the units i have are in Kg and if they are I need to pick a unit to change them to so i can have a scale what should I use. my teacher was saying something about using the K value for the scale. What is that and how do I find it.

 

[brewnog]

Are you from Sheffield sir?

 

[brewnog]

And to answer your question, no the units are not in kg.

The Rockwell number is expressed as N - h/S, where h is the permanent indentation depth in mm, and N and S are constants specific to the type of test being performed. The two most common measurements are Rockwell B and C (HRB & HRC).

Values of N and S for HRB are 130 and 0.002 respectively, using a hardened steel ball and 100kg test load
Values of N and S for HRC are 100 and 0.002 respectively, using a 120 degree angle diamond cone, and 150kg test load


Loads of info about it if you Google.

http://www.npl.co.uk/force/guidance/hardness/rockwell.html