Wheelweights and water quenching

[Possum]

When I drop my bullets into a bucket of water, how long do they have to stay in there? I was reading the post about oven treating the bullets and leaving them in room temperature water for 48-72 hours to achieve full hardness. Is that necessary for bullets straight out of the mold if I am trying to achieve maximum hardness from wheelweights?

[Edward429451]

I would think not. When I quenched some boolits, they were only in the water for a few hours until I was done casting. I sent some of the same batch of boolits to a board member for hardness testing and some air cooled also. It turned out that the air cooled WW's were 12.7 BHN, and the water quenched WW's were 27.4 BHN. They were retested two weeks later and the BHN had dropped to 22.

He's got some other theories and tests underway and said he'll start a thread about it soon. Look for it.

I can't glean any advantage to letting them sit in the water for an extended length of time. But let the light be shined by others possibly more in the know!

I'm gonna start quenching most of my cast now though.

[charger 1]

I've gotten a false high reading with a tester,but never a true 27 on quenched ww's. They usually have to get into the oven for that # to be real

[NuJudge]

The following is an oversimplification, and made without a Lead-Tin phase diagram in front of me.

Most Lead alloys at temperatures near the melting point should be an even mixture. The crystals are small, and in the context of this small size, relative to room temperature the atoms are highly mobile. Alloying element atoms do their work in one of several ways, including just displacing or getting between atoms of Lead from the crystal lattice(Solid Solution), or forming a compound with either Lead or some other alloying element atom.

When one water quenches Lead alloy bullets, one is trying to fix the alloying element atoms in the middle of Lead crystals, instead of letting them migrate to islands or the crystal boundaries. The Solid Solution alloying atom diameters are different from the Lead atom diameters. The Solid Solution alloying element atoms thereby distort the crystal atomic lattice, restraining it from bending, stretching, twisting or shearing (this is a good definition of hardening). Some alloying elements form compounds, and have the most impact on hardness if the compound formed is in evenly distributed really small islands, instead of big islands or on the crystal boundaries. If one allows it to cool slowly, the atoms will migrate. Once the bullets get down to room temperature, the speed of atom migration gets very slow, so the rate of hardness change should be really slow.

Lead is strange in that when you cold work it, it will loose much of this resistance to deformation in something between seconds to days.

The difference in atom migration rate between room temperature in air and room temperature in water is zero.

Christopher Dingell

[BOOM BOOM]

HI,
When H2O quenching the colder the H2O the better, I think.
That is why I slush quench.
I alsoput the bullets in the freezer after my casting session, untill I am ready to size & lube.

[robertbank]

I water quench my .45acp and 9MM boolits. I drop them in cold water - usually covered in ice cubes. When I am done casting I towel dry them and store them until I am ready to use them. Works for me.

Take Care

Bob

[felix]

Don't waste your time, folks. The steam generated when a boolit drops into the water protects the boolit from further "rapid" cooling. What we need is a liquid that does not evaporate at 650 degrees, the drop temp. Help is there using methyl-ethyl glycol, a new antifreeze type. It is also called poly-glycol on some jugs. Add that to raise the boiling point to something better than 220F. Higher the better, naturally. ... felix

[StarMetal]

Felix,

Pressure, the higher the pressure the higher the boiling point of water. No practical way though.

Joe

[grumpy one]

Don't waste your time, folks. The steam generated when a boolit drops into the water protects the boolit from further "rapid" cooling. What we need is a liquid that does not evaporate at 650 degrees, the drop temp. Help is there using methyl-ethyl glycol, a new antifreeze type. It is also called poly-glycol on some jugs. Add that to raise the boiling point to something better than 220F. Higher the better, naturally. ... felix

I seem to recall that glycol is quite toxic. Are you going to produce a toxic gas bubble each time you drop a bullet into the liquid?

[robertbank]

Sometimes ignorance is bliss. If I think my bullets are harder by water quenching then they are! Loved chemistry but hated physics and your post is just another reason why I disliked it so much. :mrgreen:

Besides steam at 100C is cooler than 650F so bankers logic says it must cool the bullet once the bullet temp drops to one degree below 100C. No steam then. Probably no effect either but see my first sentence.

Take Care

Bob

[Possum]

Hmmmm....good discussion. Might just go with the air-cooled since they are giving me good groups and no leading.:-D

Seriously, I appreciate the discussion. Couldn't have got my mould/bullets this far without this forum.

[grumpy one]

Sometimes ignorance is bliss. If I think my bullets are harder by water quenching then they are! Loved chemistry but hated physics and your post is just another reason why I disliked it so much. :mrgreen:

Besides steam at 100C is cooler than 650F so bankers logic says it must cool the bullet once the bullet temp drops to one degree below 100C. No steam then. Probably no effect either but see my first sentence.

Take Care

Bob

I'm sure Felix is more than up to making his own points, but the issue with steam is that it has very poor heat transfer characteristics compared with water, and once it is steam it is not limited to 100C. The gas bubble that forms results in the temperature of the lead dropping considerably more slowly thereafter. Hence the higher boiling point of glycol improves the heat transfer rate.

Industrial quenching is usually done in oil rather than water, which gives a much higher boiling temperature but is more difficult to remove afterwards, and also doesn't transfer heat as well as water does.

Geoff

[StarMetal]

yup, steam isn't limited to 100 C. Example on the old Babcock Wilcox 600 lb M type boilers, such as used on alot of naval ships during WWII, steamed at 600 lb steam pressure and the steam temperature run about 490 F something, but if the superheated steam side of the boiler was run, then the saturated steam was heated to 850 deg F. Some really nasty dangerous steam I might add, also invisible to the naked eye and it didn't even give off the condensation vapour that most folks mistaken as "steam".

Joe

[Duff L Bagg]

At 14.7 PSIA (atmospheric Pressure) steam will not get any hotter than 100C. In order to raise the temp of steam you must raise the boiling point of the water. That is why a car radiator runs a 14 psi radiator cap raising the boiling point to near 260F. Get a hole in the radiator and the boiling point is lowered.
That being said the steam around the bullet can be no more than 100C.

[robertbank]

Well if that is true then a bullet hitting the water at say 200C would be cooled by steam at 100C. n'est ce pas! My French isn't very good but that I think that means "right'. Water quenched bullets do get harder. There is a good essay contained in Lyman's Cast Boolit Handbook on the subject.

Take Care

[fatnhappy]

OK. Toss this into the mix, mostly because I consider the steam issue inconsequential.

To create "steam" you first have to change phase, which as I recall (been 20 years) runs around 540 calories/gram. What's the specific heat for lead? Anyone know offhand? Then consider you're throwing lead bullets into water. What does steam do in a water column? It gravity segregates, just like the lead. Steam goes up and lead goes down in the water column. Consider this, if steam is being generated at a microscpic level as the boolit traverses the water column, doesn't it stand to reason that such steam is a result of the desired energy change? Kinetic energy as expressed by temperature is being transferred from lead to water. Further, steam, which is water vapor, still has an enormous heat reserve and cools at the same rate as liquid water by mass. The only negative from our viewpoint is its relative transfer rate is slower. Does that matter since the bullet does not retain contact with vaporous water, since each gravity segregates in opposite directions within the water column?


First, I'd like to see the delta H change of a 300 grain bullet from 800' to 70'F. Then I'd like to compare that quantum against a phase change, just to see how many grams of steam are generated. Most likely, none, especially since it's part of a greater system (bucket).


I remain incredulous. Especially since my bucket dropped WW boolits run around 26 BHN, and I've had them tested at the material science lab at RIT. Oven hardend WW boolits run about 30 with my technique and alloy.

[grumpy one]

A technical point in case anyone cares: while saturated steam at atmospheric pressure is at 100 C, superheated steam at atmospheric pressure can be at much higher temperatures. That is the nasty invisible stuff that Joe mentioned. The limiting temperature for superheated steam at atmospheric pressure is the point where the water begins to "dissociate" into hydrogen and oxygen, at 1700 C.

When the bullet gets dropped in the water, the water in contact with it boils. From then on the bullet is dropping out of the steam bubble toward the bottom of the bucket, new steam is forming around the bullet, and the steam bubble is rising due to being lighter than water, so as the bullet sinks part of it is encountering water and the rest of it is surrounded by a steam bubble. If you could raise the percentage of the bullet's surface that is surrounded by liquid, and decrease the percentage surrounded by a bubble, it would cool faster because heat transfer to the liquid happens much faster per square centimeter of bullet surface than heat transfer to the gas, so you will usually cool the bullet faster if you use a liquid with a higher boiling temperature, or if the liquid is at a lower temperature before it gets heated by the bullet. There are some other issues that affect this slightly; different liquids have different heat transfer coefficients, and they also have different viscosities which affects the speed at which the bullet sinks through the liquid (Stokes' Law). However using ice water will slightly increase the cooling rate of the bullet, and using glycol instead of water will also increase the cooling rate. Now if you really want to chill those bullets, drop them into a bucket of liquid hydrogen, if you happen to have one handy. Personally I'd rather use liquid nitrogen, even though it isn't as cold - it isn't as dangerous, either.

Now I've gotten suckered into posting a whole lot of boring technical stuff, but at least it was fun.

Geoff

[Bass Ackward]

Or .... control what you can control. Lead transfers heat slowly. Drop smaller diameter bullets. They will cool faster. :grin:

[charger 1]

As I was told by one wise lad on here."Cool em quick then leave em in a warm place" After a rapid quench(iced water) they finish their hardness better in the stove with the gas pilot light on

[NuJudge]

Add lots of salt to the water. It causes the steam bubbles to collapse more quickly. The only problem is that you will have to wash your bullets.

There may be other such agents.

Christopher Dingell

[robertbank]

Kind of reminds me of the phrase " He couldn't see the forest for the trees". Dropping bullets from the mold into water increases the bullets hardness. If that is the objective then objective achieved.

I would be interested to know how long the bullets retain that increased hardness. Not why, (cuzz I hate Physics) but how long. Anyone do tests? I ask because I do a lot of my casting well ahead of time and it maybe months before the bullets are shot. All my bullets are stored at room temperature.

Take Care

Bob

[Rooster]

Yes, I would like to know the answer to this also as I too cast well in advance of shooting, I don't lube until I reload if this makes any difference. I would also like any input on the oven annealing aspect and its shelf stability. I have not done this yet but would be interested.

[Larry Gibson]

Kind of reminds me of the phrase " He couldn't see the forest for the trees". Dropping bullets from the mold into water increases the bullets hardness. If that is the objective then objective achieved.

I would be interested to know how long the bullets retain that increased hardness. Not why, (cuzz I hate Physics) but how long. Anyone do tests? I ask because I do a lot of my casting well ahead of time and it maybe months before the bullets are shot. All my bullets are stored at room temperature.

Take Care

Bob

I recently re-read an article (may have been out of the Cast Bullet booklet or supplement from the NRA) where bullets cast of WWs had an air cooled BHN of 12 were tested after water quenching from the mould. If I recall correctly the initial BHN was in the high 20s, maybe 28, then after a couple weeks went down and stabilized at 22 BHN. Don't quote me on those #s and I will check tonight or if someone else has the books handy could check? I think the article also pointed out and proved that you must be casting "hot" for the quenching to be truely benificial.

I have found this to be the case when water quenching WWs, reclaimed 22LR and magnum shot alloy. While I don't have the tools to test BHN on smaller bullets I do on larger ones of .378+ as I use the ball bearing between the bullet and pure lead method. I have found bullets to be consistantly harder if cast "hot" and then dropped imediately into water from the mould. "Hot" being that the bullets are either close to frosting or completely frosting.

Larry Gibson

[robertbank]

Thanks Larry will look forward to your conformation.

Regards

Bob

[454PB]

I'm still continuing an experiment on this very subject. Since it will require hardness testing on a long term basis, I can't say yet what the final results will be. What the preliminary results show is that QFM boolits (quenched from mould) harden in about 4 days to BHN 26 to 30 when cast from WW. If they are sized a week later, they maintain their hardness for several weeks, then begin to resoften. When they are sized immediately (within hours of casting), they gradually harden and continue to harden, no resoftening has been obseved yet. I too have done extensive reading by Dennis Marshal and find it all mind numbing and boring. I'm not a metalurgist and don't even really care how all this works, just that the effects are consistently reproducable.

My experiments are not all encompassing, and are only to prove to myself that heat treating is NOT the only way to harden boolits long term. Up until I started this, I was convinced that that was the case. I also falsely assumed that the hardening was only on the surface, which is not the case. I've tested to 1/3 diameter depth and found the hardness the same that deep as on the surface.

Were it not for the rapidly escalating cost of gas checks, I wouldn't even be screwing with this, I'd rather apply the GC than all the added steps involved with quenching or heat treating.

[robertbank]

Thank you for your enlightening post. Now I will have to change the way I go about casting, resizing and lubing. Ah my hobby and knowledge grows.

Take Care

Bob

[hunter64]

I have a book of publications that the NRA did in the 50-60's and early 70's and they tested hardness after water quenching and heat treating. For heat treating to be the most beneficial that mix has to have antimony in it of over 3% so Lyman #2 or higher. The bullets have to be sized within one hour of being quenched in the water, if they are left even for a day the hardness drastically falls off after 3 months. If you size them within the hour then the hardness stays for and extra 2 years or so from there experiments. They tried bullets cast from 1 month up to 13 years and they start to loose there strength after about 6 weeks and decline to a standard hardness after 6 months and basically stay there. You gain about 5 bhn with a properly heat treated bullet over water quenching depending on the mix of course.

[charger 1]

I have a book of publications that the NRA did in the 50-60's and early 70's and they tested hardness after water quenching and heat treating. For heat treating to be the most beneficial that mix has to have antimony in it of over 3% so Lyman #2 or higher. The bullets have to be sized within one hour of being quenched in the water, if they are left even for a day the hardness drastically falls off after 3 months. If you size them within the hour then the hardness stays for and extra 2 years or so from there experiments. They tried bullets cast from 1 month up to 13 years and they start to loose there strength after about 6 weeks and decline to a standard hardness after 6 months and basically stay there. You gain about 5 bhn with a properly heat treated bullet over water quenching depending on the mix of course.

So are we basically saying that heat treating works for high pressure loads if you can calculate how many you'll need load and use in one hunt then through em out???

[Bass Ackward]

The problem with this is vast because there are so many different levels of WW and so much disinformation. WW from the 60s were 9% antimony. Today, 2%-4%. And the problem persists because of disinformation that is passed on and on.

I have straight WW material bullets that were made in 1991. BHN one day later ran from 24-28 BHN. 1 month later, most were 27- 28. One year later stored out in a garage from 20 - 135 degrees, BHN was 20. Just measured one again 15 years later, 20 BHN. I have seen 18 as the softest with WW.

Linotype and Lyman #2 will not heat treat unless you add arsenic. But the harder a mix air cools, the harder it will heat treat up to about 40 BHN and the harder it will stabilize one year later. Meaning that if HTWW comes back to 18-20, then HT lino will stay above 22BHN which is the hardness air cooled or derived from it's chemical composition. Consequently, the softer a mix air cools the softer it will be one year later. Bottom line is that you have to measure it to know for sure.

Regardless of how it is HT'ed, if it is sized, it softens where .... it .... was .... sized back to air cooled hardness of the parent metal. HTing WORKS because it causes a cristaline pattern to form. Not from any chemical change of the lead mix. Disturb the formation of that pattern and the sized part never hardens. Did you catch the key word NEVER. The rest of the bullet will harden, but the process stops hardening the moment it is sized whether that is right after quench or 6 months later.

This is another key reason for misinformation. If pressure is causing you problems with leading or inaccuracy, then a bullet that is hard through and through and soft on the surface is stronger to resist deforming pressure than one that is not regardless of how soft the skin is. If you are leading from a rough bore or poor lube, then you will probably find more success from an oven HT bullet that was sized before and is hard both ways. The highest percentage of problems comes from PRESSURE so most guys think WDWW is great stuff. If this is you, fine! Other guys will tell you that they hate water dropping and only changing the mix chemically produces better accuracy.

You have to understand the process and your particular problem that you are trying to solve to know where to go with it.

[Larry Gibson]

Thanks Larry will look forward to your conformation.

Regards

Bob

On page 124 of the NRA Cast Bullets is a chart That shows the aging of a hardened alloy. The article it is in is Stronger Bullets With Less Alloying by Dennis Marshall. It is a fairly comprehensive article that also explains the whys of hardness changing during storage and why antimony is the principal hardening agent. Also in the RCBS Cast Bullet Manual on page 33 is a small dissertation on Hardness and Aging Effects. I still haven't found the exact article with the test I was refering to but will continue to look. However, the two mentioned references will give you a good idea.

Larry Gibson