The Old Argument: Actual Brinell Measurement/Hardness

[Chill Wills]

If that is the case, there are a lot of really bad charts and info floating around for a century or more.
Interesting!!!

Just for grins, what does pure Pb come in at?
Silicon, Si is listed in one alloy in your post, (0.1%) Pb-Sn-Si. You don't normally see that other than background contaminant.

[mehavey]

I see the (less-than-1/10th-of 1%) silicon to be residual from the gross ore smelting process.

Pure lead (RotoMetal) comes out at 4.5-4.6 BHN.
Reactor Grade lead just a decimal point lower

[fc60]

Greetings,

We had a batch of metal X-Ray analyzed at the local scrap yard.

Came back with a high Silicon content, about 2%.

Next visit, we asked the yard man to clean the lens of the analyzer.

Testing the same ingots, the Silicon value disappeared!

Cheers,

Dave

[mehavey]

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[Chill Wills]

I see the (less-than-1/10th-of 1%) silicon to be residual from the gross ore smelting process.

Pure lead (RotoMetal) comes out at 4.5-4.6 BHN.
Reactor Grade lead just a decimal point lower

Thanks for getting back to me. The BHN for Pure Pb is on track with many sources. At least that hasn't changed.

BHN has been a keyboard conversation for the 25 years I have been following it. Especially in the BPCR world.

I am very open mined. Without jumping in with both feet, one thing I think I know is the BHN of any alloy is not fixed, but Dynamic. There are so many external conditions that can and will effect it.

Thanks for any time and work you have done.

[mehavey]

Binary Lead/Tin alloys aren't affected by either quenching or aging.
They are effectively what they are, near immediately, and stay that way.

Ditto actual Lyman#2 at 90/5/5 Lead/Tin/Antimony.
I've tested 30 minutes after -- and three years after -- still BHN 15.
(I'll have to go re-heat/fast-quench a couple of bullets again and re-check there)

Add any arsenic... divert from equal parts tin/antimony... and you're in another ball game.

[mehavey]

See above belief that (true 90/5/5) Lyman #2 is not affected by quenching.
...and that I would re-check.

I recast both air cooled and fast-quench (direct from hot mold into ice water) RotoMetals actual Lyman#2 last night.

Air-cooled was BHN 14.9 from 30 minutes on to current 24 hours later -- no change
Fast quench went from BHN16.6 one hour after; 18.6 four hours later; and now 21.2 twenty-four hours later.

I stand self-corrected.

[Chill Wills]

Binary Lead/Tin alloys aren't affected by either quenching or aging.
They are effectively what they are, near immediately, and stay that way.

This is been in interest of mine for decades. This is what I think I know about Pb - Sn alloys and time.
Look to the bottom sited quote below.

I have other data including samples I have tested on my own. This isn't a hill to die on for me. Just interesting.
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Totalmateria

Materials science database

Heat Treating of Lead and Lead Alloys

Abstract:
Lead is normally considered to be unresponsive to heat treatment. Yet, some means of strengthening lead and lead alloys may be required for certain applications. Lead alloys for battery components, for example, can benefit from improved creep resistance in order to retain dimensional tolerances for the full service life. Battery grids also require improved hardness to withstand industrial handling.
Solution Treating and Aging

Adding sufficient quantities of antimony to produce hypoeutectic lead-antimony alloys can attain useful strengthening of lead. Small amounts of arsenic have particularly strong effects on the age-hardening response of such alloys, and solution treating and rapid quenching prior to aging enhance these effects.

Hardness Stability. For most of the two-year period, the solution-treated specimens were harder than the quench-east specimens. Other investigations have also shown that alloys cooled slowly after casting are always softer than quenched alloys. The alloys with 2 and 4% Sb harden comparatively slowly, and the alloy containing 6% Sb appears to undergo optimum hardening.
A useful level of strengthening normally requires solute additions in excess of the room-temperature solubility limit. In most lead alloys, homogenization and rapid cooling result in a breakdown of the supersaturated solution during storage. Although this breakdown produces coarse structures in certain alloys (lead-tin alloys, for example), it produces fine structures in others (such as lead-antimony alloys).

In alloys of the lead-tin system, the initial hardening produced by alloying is quickly followed by softening as the coarse structure is formed.