A little fun with heat treat.

[MBTcustom]

a couple days ago, I heat treated some boolits and they came out so hard that I bent the handle on my Star sizer trying to ram them through.
I posted about this over in the Star section, and honestly I was dumbfounded that this alloy could produce such amazing hardness.
The alloy is just 50/50 COWW/SOWW and there should be no tin in it (or very little) as I have checked all my COWW alloy and verified that it has almost nothing in the way of tin, and it is rare for SOWW to contain that element.
Based on my estimates, and having used this alloy before to blow up the deer in the link in my signature line, and having tested that alloy to exactly determine the content.(See post #215)
This alloy has 1.5% antimony and no tin.

I decided to replicate this scenario to see of I can duplicate the results that I got the other day that bent up my Star. The goal was 27BHN, just half a day after heat treating.
So I took 15 boolits out of the oven and quenched them at 11:15 AM and started checking them 15 minutes later:
11:30 Impression was .074 dia. = 9.2 BHN
11:50 impression was .064 dia. = 12.5 BHN
12:05 impression was .060 dia. = 14.3 BHN
12:35 impression was .058 dia. = 15.4 BHN
1:20 impression was .054 dia. = 17.9 BHN
2:20 impression was .048 dia. = 22.7 BHN
5:20 impression was .046 dia. = 24.8 BHN
7:20 impression was .044 dia. = 27.2 BHN

There it is fellers. Cool huh?

[Yodogsandman]

Thanks for putting some numbers up, goodsteel, good to know. That's why I broke my table today! I HT'd and PC'd last Friday! I was getting boolits stuck in the sizer and needed a big pipe to move the handle to remove the boolit! My sizer was c-clamped to the table but, it broke before the c-clamps gave up. My alloy was 9 1/2 lbs of COWW and a half pound of 50/50 bar solder. Heated to 450 degrees for 45 minutes, PC sprayed and returned to the oven for 25 minutes at 400 degrees. Then quenched in cool water. The boolit started at .362", with PC it was about .368" and I was sizing down to .360"! Kind O' worth it to size first, then heat treat. No sizer (RCBS LAM II) was injured during this exercise!

[RickinTN]

Tim,
What was the heat treat temperature and for how long? Curious minds need to know.
Rick

[35 shooter]

I don't have a bhn tester, but have had someone else test them after only a couple of days and they were at 27 bhn. This was with straight ww ht @ 465* for 1 hour and water dropped.
What temp. did you heat yours at? I've shot mine within 48 hrs. of ht, and get the same groups as if i waited a week or two as far as i can tell. LOL, i knew they were getting hard quick.

[MBTcustom]

I heat treated at 350 degrees first which exhibited no change even after several hours.
The second batch (and the ones I am writing about) were soaked for 1.5 hours at a temperature of 450 degrees F.

I would like to add at this point that the hardness seems to have leveled off here about 7 hours after the quench and is not rising anymore.

Also, I have taken one of the boolits and sectioned it about 1/8" at a time and taken a measurment right in the center of the boolit (all the previous measurments were taken from the meplat).
There is no change through the middle of the boolit, and it is exactly the same as the surface measurment.

[35 shooter]

I have noticed over time that if i size and lube within 24 hrs., they go through the sizer easier. Even after 12 hrs. i can hardly make a mark on mine with a fingernail. After 48 hrs. forget the fingernail and there is more resistance to sizing. I guess the main molecular stabilizing is about done at that point.
It's very interesting that the hardness is so uniform all the way through the boolit so quickly. Guess i can quit worrying about whether or not i was sizing too quickly. In my limited experience it hasn't made a difference in accuracy and now i think i see why.

Thanks for posting this...very interesting!

[RickinTN]

I've always sized first then heat treated. My reasoning was that I didn't "break the skin" on a treated bullet. I think your test results will tell me there is no need in this worry. I think I will continue to size then treat as it will be easier on the equipment. Your results beg the question in my mind....Do you have any idea as to possible As content? Are you getting these results because of the presence of arsenic? or are you getting them in spite of having low or no Arsenic? Curious.
Rick

[MBTcustom]

There is no arsenic in this alloy. I have seen it in extremely small amounts in some COWW samples, but it is very rare.
That said, I do intend to have this alloy analized yet again just to remove every shadow of doubt. After all, this is COWW alloy. It could have almost anything in it.
I find it funny that people worry about arsenic and bring it up all the time, but make no mention of the other elements that I have seen in COWW occasionally in equal or greater ammounts/regularity.
FOr instance:
What about Gold? Found that once. Or rather the machine thought there was .02%?
Nickle?
Copper?
Tungsten?
Sulfur?
Gallium?

Usually these metals are so minute that the feller running the machine says it could be a glitch in the readers, and cannot be trusted. Just because it says there is .02% gold, doesn't mean it's in there. It just means that the frequency was kinda lookin that way for a nanosecond.
Really, it makes sense too. I mean, would you notice if I dropped one grain of salt in your sweet tea? You'd really need at least 1/2% to even notice, and that's the same thing that the people in the know have told me.

Anyway, that's why I test all my alloys. There really isn't anybody that can stand there and say with any degree of confidence that they know what is in their alloy or what it does unless they have access to a machine like this and have done a lot of experiments with it
As it is, what I have here I consider as accurate as if I had bought 98.5/1.5 alloy from the foundry. It may not be exact, but it's going to be really darn close. I'm going to re-verify just to be on the safe side though.

[btroj]

I find it funny that people worry about arsenic and bring it up all the time, but make no mention of the other elements that I have seen in COWW occasionally in equal or greater ammounts/regularity.
Worry? I don't see any worrying.

Why does arsenic matter? Because it is a great grain refiner and greatly enhances heat treating of antimony bearing lead alloys. It also does so at extremely low concentrations. Most other elements have no bearing on heat treating so they can be ignored.

No worrying going on here, just paying attention to trace elements that matter.

[MBTcustom]

I find it funny that people worry about arsenic and bring it up all the time, but make no mention of the other elements that I have seen in COWW occasionally in equal or greater ammounts/regularity.
Worry? I don't see any worrying.

Why does arsenic matter? Because it is a great grain refiner and greatly enhances heat treating of antimony bearing lead alloys. It also does so at extremely low concentrations. Most other elements have no bearing on heat treating so they can be ignored.

No worrying going on here, just paying attention to trace elements that matter.

Based on what Brad? I mean if you are sure that your alloy has Arsenic in it, then I understand, but often it does not have any such thing. I think a lot of the talk about As is there, not because COWW have it in there, but because the alloy calculators claim it does. Big difference.
Now I'm not arguing that COWW have no As ever, I'm just saying that I have measured enough samples that had none whatsoever that it should never be a forgone conclusion, and it's presence in COWW alloy is certainly not dependable by any stretch of the imagination. That's all I was saying.
You say it's a great grain refiner? Awesome! I'll take your word for it and try to find a way to dope my alloy with it. But it's got to have it in there in the first place in order to have that effect, and this alloy has none in there, so it's a moot point in this test.
BTW, Brad, it was your testing that inspired me to do this in the first place. Feel free to kick in here if anything you have seen is different than what I am posting and we'll hammer it out OK?

OK, moving on. Today, I will HT boolits cast from Lyman #2 alloy that I built here based on analyzed alloys precisely weighed and mixed. Again, I have not measured this alloy to be certain it is what it is supposed to be, but I am reasonably certain that it is very close to 90/5/5 alloy. I am not a metallurgist nor a chemist. I just have measurement tools, I use them and report what they said with no bias. That's what I do. Does it matter? I don't know. The information is pretty solid though. I'll leave what it means and how it's applied to the folks who are smarter than me with that sort of thing.

What I want to determine is if the tin hinders the rapid heat treating or the hardness attained, or if it has no effect. We shall see.

[btroj]

Don't take my word for it. These are a few good resources where people did the work.

http://www.castpics.net/subsite2/Gen...%20Arsenic.pdf

http://www.lasc.us/heattreat.htm

What I was commenting on is your use of the word "worry". We aren't worrying over anything, we just know that arsenic plays a vital role in heat treating of antimony hearing lead alloys.

Want a good source of arsenic for alloy? Use some magnum shot.

[RickinTN]

"What I want to determine is if the tin hinders the rapid heat treating or the hardness attained, or if it has no effect. We shall see."

It's my understanding that tin will hinder the effectiveness of heat treating both in time and amount. I'm looking forward to your results to see if they bear this out.

"Want a good source of arsenic for alloy? Use some magnum shot."

I usually do add some magnum shot into the alloys which I know I will heat treat specifically for the As content. Does it help? I understand it does, but I don't have a hardness tester....yet. Guess I need to put that on the list soon.
Looking forward to your results.
Rick