Is There a Formula to Cx Odd Ball Alloy Ratios Using a Known Bhn?

[John Boy]

Example: Bhn 6.3 ... Is there a formula to calculate the 1:X alloy ratio for this Bhn?

All the Bhn to alloy ration calculators stop at 1:40. I have a lot of aged scrap lead ingots that are close to known ratios and many that are not. What I would like to do is build a table of the unknown ratios and those ratios that are in between the knowns in the calculator programs

[lwknight]

Anything with a bhn of 6.3 or softer is considered pure lead.
Only the purest of pure oxidizing grade lead is a true bhn 5.0.
It takes almost nothing to make lead noticeably harder than pure.
That's probably why the charts stop where they do.
Sorry , no other info available from here.

[sqlbullet]

If you have a known binary alloy of lead/tin, then what you propose, determining constituent makeup based on BHN would work.

However, this falls apart if your alloy is not know to be only lead and tin. Reason being there can be multiple different hits on a given BHN by different ternary alloy ratios. Hardball and Lyman #2 are very different ratios of lead/tin/antimony, but come up about the same on BHN...about 16-17.

There is a BHN calculator around here somewhere that will show you the approximate BHN of a known alloy, but it doesn't go the other way. You could combine BHN, solidus/liquidus points, and specific gravity tests to get a good idea.

[el34]

Hardness of Lead Alloys (chart I downloaded from somewhere)

Alloy----------% Pb--% Sn---% Sb--BHN-----Equation BHN

Monotype------72.0---9.0----19.0---28.0----28.7
Stereotype-----80.0--6.0-----14.0---23.0----23.2
Linotype-------84.0---4.0----12.0----22.0---20.8
Lyman#2------90.0---5.0-----5.0----15.0----14.7
Taracorp-------92.0---2.0-----6.0----15.0----14.7
1:1 Lead/Lino--92.0---2.0-----6.0----15.0---14.7
Electrotype----94.5---3.0-----2.5----12.0----11.8
Wheel Weight--95.0---0.5----4.0-----9.0----12.4
10:1------------91.0---9.0----0.0----11.5----11.2
16:1------------94.0---6.0----0.0-----11.0---10.3
20:1------------95.0---5.0----0.0-----10.0---10.1
30:1------------97.0---3.0-----0.0-----9.0----9.5
40:1------------97.5---2.5-----0.0-----8.5----9.3
Pure Lead------100.0---0.0-----0.0----5.0-----8.6 (obviously wrong)
Roto Suprhard--70.0---0.0----30.0--no spec--36.2

There is an equation bouncing around-
Brinell=8.60 + (0.29*Tin )+(0.92*Antimony)

But this doesn't match lead=5 BHN, so it throws in a confusion factor. I added the last column above which calculates the hardness of each alloy with the formula. It comes pretty close most of the time, just not when the alloy gets close to being pure lead.

You can possibly use the chart and interpolate or finagle the equation to accomplish what you're trying to do.

edit- well poop, all the nice columns got de-formatted. Edited to replace spaces/tabs with dashes.

[John Boy]

Thanks Gentlemen - looks like there isn't a formula to reverse Cx Bhn to an alloy ratio.
Appreciate your responses & "el" - neat chart. I'll copy it to my computer for future references