Units of Hardness

Rockwell hardness scale is one common standard.

Dear Mr.Nithin,

BRINELL's HARDNESS is another system of measuring Hardness, denoted as BHN.

A thumb rule, BHN/3 = Tensile Strength, in Kg/cm^2 Approx. For round shafts above 150 MM correction factor is to be applied.

DHAYANANDHAN.S

And Mohs. And Brinell.

Why don't you just do your own search. You DO know how, don't you?

There seems to be an epidemic of helplessness going around.

Is there somewhere that I can search, that will explain to me how I can do my own search? You know... a search-search?

Just wondered what happens when you google search.

search.search

Is that kind of like googling "How do I find the internet?"

The question was "...to calculate hardness", not "...to express hardness".

Although, "Are there any units..." does confuse the issue.

Please clarify the question if it has not been already answered to your satisfaction. Rephrase it.

So far we have Rockwell and Brinell for metals, and Moh's for minerals. Let's throw in durometer (several scales) for elastomers. A bit more esoteric: Jominy for hardenability of metals.

For more amusing purposes: angle of dangle.

GPG (Grains per Gallon) for Hardness of Water

Is there a metric for hardness of test questions and the like?

Who wants to be a millionaire?

dB lost, for hardness of hearing

M. Kumar -- Scroll down to section 7. and also the precediing Fig 22 for a helpful chart on the following web page:

http://www.calce.umd.edu/TSFA/Hardness_ad_.htm#6

This is a result form a Google search on the words "tensile strength relationship rockwell".

This search produces other useful information to help answer your questions.

Ed Weldon

Hardness is a property of materials that can not be expressed in scientific units of force, length, and time. This is why it is expressed in superficial units. This doesn't mean you can't predict and use hardness in your designs and products. Just be aware that it is based on superficial measurements.