Brinell hardness; why the descrepency?

[yomomma]

If you Google the hardness of lead you get a value of 5 fore pure lead. Why does rotometals use 8.6 for their pure lead value?

 

[big boar]

I'm only going to guess that they MAY have some small trace amount of impurities. Also they may have actually MEASURED the lead instead of just giving a book value. Just a thought.

 

[ryan]

Just looked at their pure lead, and the 99.9% lead ingot is approximately bhn 5
Are you looking at the right one?

 

[yomomma]

From rotometals

For every 1% additional tin, Brinell hardness increases 0.3.
For every 1% additional antimony, Brinell hardness increases 0.9.
For a simple equation,
Brinell = 8.60 + ( 0.29 * Tin ) + ( 0.92 * Antimony )

 

[legi0n]

could it be that any tin or antimony increases the hardness 3.5BHN to start with?

 

[ShawnC6]

They are wrong lol. It's 5 if it's pure. Not like 8.6 is exactly hard either.

 

[yomomma]

Technically 99.9%pure is about 4.8 and 99.99999% pure about 4.6.

Most excel spreadsheet hardness calculators use 8.6 as their baseboint.