Water quenching hardens surface only?

[DanM]

I have been told that water quenching makes boolits that are surface hardened only, and the hard layer is wiped away during sizing. Any truth to this?

[felix]

Not so; the whole boolit is hardened on a sliding scale towards the center where the hardening effect is the smallest. ... felix

[dubber123]

It is my understanding that sizing as soon as posible after quenching will maintain the highest level of surface hardness, as they tend to age harden over the course of a few weeks.

[3sixbits]

I agree totally with what has been posted so far in the replies. No old wives tales in any of it. Every bit can be sourced from the lead chemistry industry. You might want to keep in mind that quenching and heat treating and quenching is not the same thing. Give them three weeks and you'll have the best bullets, if hard is what you need.

[GLynn41]

Lyman calls it precipatation hardness -- you are changing how the lead dendrites harden--and they recomend as has been rightly stated to size quickly - even air cooled will age harden at least some -- so saith Lyman

[Ricochet]

Even better to size them first, heat treat and quench as a batch for uniform hardness, then lube.

[MtJerry]

How long after casting and sizing can you heat quench?

I have some boolits that I poured earlier this winter (ACWW) and then sized immediately fter casting.

Would heat quenching in the oven still be effective this late?

[Ricochet]

Heat treatment resets the clock. Puts all the crystallized alloy elements back into a homogeneous "solid solution," which you freeze in the quenching. Then it slowly recrystallizes into a finer crystal structure at ambient temperature. Doesn't matter how long they've been cast before you heat 'em.

[dubber123]

As the base metal composition of the metal hasn't changed, I don't see why not. The same percentage of antimony and (I guess?) arsenic should be present as the day you cast them, and those are the elements necessay to harden a lead alloy.

[dubber123]

Ricochet, you beat me to the punch on that one! Knew I shouldn't have proof read it!

[MtJerry]

Heat treatment resets the clock. Puts all the crystallized alloy elements back into a homogeneous "solid solution," which you freeze in the quenching. Then it slowly recrystallizes into a finer crystal structure at ambient temperature. Doesn't matter how long they've been cast before you heat 'em.

Thanks!

[Sundogg1911]

but how long do they stay their hardest? It's my understanding that water quenching or heat treating only lasts so long before they return to the original hardness. I stopped water dropping them for this reason. I found a box of water quenched .45's that had gone bak to about the hardness of non water quenched bullets of the same alloy. They were cast about 3 years prior (that's a guess....may have be 2 and may have been as many as 5 years) So I guess Heat treating or water quenching is good as long as you don't sit on them too long before shooting.

[Maven]

DanM,dubber, et al, Lead alloys, unlike brass, become softer after they are worked or sized. Sizing after water-quenching markedly reduces the BHN of the bullet's driving bands. Don't believe it? then have a look at Dennis Marshall's article, "Stronger Bullets With Less Alloying" in the NRA/E.H. Harrison book, "Cast Bullets" (1982). Marshall is a metallurgist who did extensive testing of both water quenching and oven heat-treatment as a simple way of increasing the hardness of wheelweights. You'll find his work is based on the scientific method rather than personal experience.

[Ricochet]

I guess Heat treating or water quenching is good as long as you don't sit on them too long before shooting.
Yeah, and if you don't lube them, you can oven treat and quench boolits a couple of weeks before your intended use of them. That's a piece of cake to do. But three years is a long time.

[oso]

Don't forget that if you lube with a large enough die so you don't resize the driving bands and don't "bump" the boolit you won't loose the hardness gained by quenching.

[twotoescharlie]

what happened to casting 'em,sizin' and lubein', loadin' and shootin' em? I ain't got no degree in metal urgy but I seem to do purty good with my blu whistlers.


TTC

[Marlin Junky]

I have checked hardness near the center of oven heat treat boolits (with an as-cast hardness of BHN 15) one week after quenching in ice water and they measured BHN 20.

MJ