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August 20, 2019, 11:44 AM | #51 |
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The Kline study has a plot for time required to initiate recrystallization vs. temperature for both 50% and 75% CW brass. The time threshold varies exponentially, roughly halving every 33K for the 75% CW, for which the function made a nice straight line when the time axis is on a logarithmic scale, but not being such a simple function for the 50% CW brass. It gives about 6 seconds (0.1 minutes on the graph) for about 833K, or about 535°C, which is 995°F.
However, other charts he has show hardness starting to change before recrystallization actually commences. Even 100°C cause some change in the yield point over a period of a week. And, get this, the hardness and yield bottom in some plots at about 30 minutes exposure, and goes up again when it is drawn out to 60 minutes. This is explained by an accumulation along the enlarged grain boundaries of, IIRC, nucleation points. I'll have to reread that. In any event, this is not nice neat all-else-being-equal parallel predictable behavior.
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August 20, 2019, 12:36 PM | #52 | |
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Nick the 550C number for 8 seconds is what I was referring to
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Do you still think that at 750F for a second or two will do anything at all in regard to case life or accuracy? That of course is the elephant in the room, it appears that unless you are willing to drop $1500 or whatever to get the AMP that anyone using a Annie/torch and 750 Templaq on the neck area is just wasting their time. I would suggest instead that people still wanting to use a torch or Annie use 450F Templaq 1/4 inch below the shoulder on the case body for safety reasons and not worry if they get above 750 or even 1000 F in the neck/shoulder area. Indeed it looks like the old plumbers torch till the necks glow dull red might just give the most cost effective anneal of all
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August 20, 2019, 04:21 PM | #53 |
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METLAB's claim that 120 HV is way too high tells me they just aren't used to the cartridge case field. About this time two years ago I sent samples of 10 different headstamps of new bulk cases to board member Bobcat45 who worked professionally in making hardness measurements and metallographs for a major mining company, including having access to a micro Vickers hardness tester. The results for sectioned necks ranged from HV 96 (RP) to HV 124 (Hornady) with the average at VH 107 with an SD of HV 7.7. So the AMP result is just under 1.7 standard deviations above the mean and is not at all outside the normal range for new commercial brass at all.
Even if we think the commercial brass makers have got it all wrong for most of the last century, from the ASTM we have that HV 120 is about equal to Rockwell B scale 67. From Klein's paper, at 425°C, page 14, Table 4.11, we can see that a 50% CW sample drops from RB87 to RB67 in about 4 minutes. From Page 11, Figure 4.2, we see the elongation before break of a 50% CW sample in 425°C grows to about 30% in that same time. Therefore, it is easy to see it provides 10 times the elongation necessary to someone reloading .308 Win in conventional steps to prevent neck splitting. Tested virgin brass Federal Hornady IMI Lapua LC Norma RP SIG Starline Winchester From Bobcat45's images, the top is Hornady and the bottom is RP. RP is close to being 80:20 brass, which accounts for some of the appearance difference. From Bobcat45: "Note that the Vickers hardness is denoted HV500 for a 500 gram load, and cand also be called DPH for Diamond Penetrator Hardness.For a time, aerodynamics were famously able to prove bumblebees couldn't fly. I don't think we stopped believing they could fly because of that. We accepted that they could fly and that we just weren't understanding something and finally some graduate students solved it, IIRC. We also know lower temperature stress relief works by observation (Herrett and Milek again and this board's members stopping splits, even with the candle method) so the question is why, and not if. What are we missing? One of Klein's tables shows elongation at break increasing occurring at just 100°C over a period of a week. There is no recrystallization happening at that low temperature so there is some other mechanism for releasing some of the stress before recrystallization is clearly established. I don't see an explanation or discussion of that anywhere. It would be an interesting thing for a grad student to undertake and quantify.
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August 20, 2019, 04:48 PM | #54 | |
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It gets pretty deep into safe and a variables (ask Boeing what a bad sensor can do) Agreed its the best, disagree its the only one that works per inductive.
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August 20, 2019, 05:47 PM | #55 |
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RC my only question about the Annie is how do you know what the hardness of the necks are after your operation. From every thing I am reading and there are pages of links now supporting this but heating your case neck to 750 for a couple of seconds accomplishes nothing except a color change
For that matter according to METLAB heating to 1050F for 8 seconds accomplishes nothing except a color change @Nick As far as what is acceptable hardness I could care less. It's a simple question - does keeping a case at 750F for 7 seconds accomplish anything as far as reducing brass hardness? No sources that I can find says it does so if the report you keep referencing does I would like to read it. So if you can provide a link to the Kline report I would appreciate it. I tried googling it with no results and if I have ever looked at it the name does not jump out at me. edit nevermind Nick found it behind a paywall but if it does say that appreciable change can occur that soon is everyone else wrong ? many reputable sources now state that 750 - 1000 degrees takes minutes to make any significant changes
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August 20, 2019, 09:36 PM | #56 |
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Doesn't much matter what the sources say if they aren't checking what we are, which is do neck splits stop? They do. It's the explanation we are seeking and not the authoritative data that fails to explain it.
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August 21, 2019, 07:18 AM | #57 |
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well Nick you may want to consider a new career as politician, lol
BTW for years now I have been lobbying for some real tests conducted under a controlled scientific study on case life and velocity for annealed vs non annealed brass. No annealing machine manufacturer has taken me up on this yet or if they did conduct a real study were too embarrassed to publish it. Most likely the latter since no one would want to say here buy our $300/$500/$1000 machine it will make a pretty blue ring on the necks of your cases I have linked several studies that show that at the temperatures and times that have we have been using no grain structure changes occur. Without the grain structure changes stress fracture will continue to occur. I have no idea why you will not give a direct answer on this since it is the only logical conclusion If I were really concerned with case life I would go to the 450 templaq on the case body 1/4 or 3/8 inch below the shoulder method. Heating the case neck to dull red is not going to harm that brass in the least and might even get it to the temps where some changes might actually occur. Or I would drop 1500 on a AMP that does get the brass hot enough and does it in a very controlled way and actually does anneal the brass. Expensive option but it seems to do what it claims which is get the grain structure back to the annealed state. That is more than I can say for the other options
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August 21, 2019, 02:07 PM | #58 | |
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I have repeatedly laid out my methodology - I think anyone would agree is comprehensive as can be done by an individual without the unlimited resources. It does not depend on a single source and it has rubber meets the road real world cross check. 1. No split necks or shoulders 2. Bullets seat with minimal force when they got harder and harder before (duh, its work hardened brass!!!!) If it Quacks like a Duck, has Duck DNA, has Duck Feet, Swims like a Duck, flies like a Duck and produces Duck offspring we can conclude its a Duck. Clearly you want to deny that ducks exist. In one last effort I will present the following. A number of times in my career, I came across a circuit that quit working and had worked fine before. When I looked at the logic, I could not determine why it worked in the first place. I do know how those circuits are SUPPOSED to be wired and they were not. That standard wiring had a logic that worked every time. So I re-wired it to a standard logic circuit and never had another problem. I don't have to understand why it used to work, I just need to wire it to where 1. It worked 2. Anyone who followed me could find a failure in that circuit because it worked the way it should. There are a bazillion things in the world none of us understands. They are still arguing about electron flow. Does it matter? No, all you need to know is IT WORKS and how to make it work consistently. People have done so with various methods for a long time. Hell I can heat the damned case to dull red (I have done so) what I have is a messed up piece of brass as it nor longer is smooth its mucked up skin mottled that will not work in a die right. I DO NOT CARE IF IT MAKES BETTER ACCURACY!!!!~ Cases cost 20 cents each and if I quadruple the life of the case the Anneal will pay for itself and I don't have to keep buying cases all the time. When the Sun rises in the East and not the West and your facts say it rises in the West then you need to check your facts or accept you don't understand it.
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August 21, 2019, 03:25 PM | #59 | ||
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Your proof seems to be that you don't split case necks..ok I have never split a case neck either does that prove anything? I don't think so. As far as my bias I am going to do one last experiment. I have just sized and trimmed 50 Lapua .260 rem cases on their 5th reload. I am going to "old school" anneal 15 of them ie the drill and torch routine, the Annealeze needs new wheels. Then I will take those 15 and 15 which have never been annealed and load them exactly the same. I will seat the bullets on the arbor press using a bit of graphite lube and shoot 3 each groups at 600 yards across a chrono with the annealed and non annealed and see if there is any difference in SD which is my main concern. Like I have said thousands of cases and no neck splits. If I do see a difference however I will get some new wheels for the Anealeeze, or just keep using the drill and socket method. I don't expect much difference though the attachment are is the same cases I am cleaning now and this was the last time they were shot. Most of the reason for the test test is just a 600 yard sight in and seeing if I need to back off a grain due to higher temps. It will be 90 - 100 on the range and the attachment was shot when it was in the 40's Another interesting test would be if a annealing manufacturer or someone with the resources would take 100 or so .308's and divide them into three groups. Shoot 1/3 through a military rifle, 1/3rd through a off the shelf hunting rifle, and 1/3 through a match barrel. I shoot match barrels and like I said, I have never had a neck split and it could be like Nick said, that is due to the tighter tolerances of my chambers or the fact I use premium brass. Military rifles and Walmart rifles might see more neck splitting than I get. Winchester or LC cases may be more prone to neck splitting, I have no clue but annealing for case life is not a concern for me On a different note I know why the salt bath annealing did little or nothing. Quote:
A induction unit operates entirely differently since the heat is generated by the metal itself which is the most efficient of the three methods and would be the least prone to heat migration assuming the magnetic field is "tight" enough to generate sufficient heat in the neck shoulder area without overheating the case body.
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August 21, 2019, 03:48 PM | #60 |
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First the obvious...
The "simple" methods of annealing yield an increase in ductility. And a few things are fairly clear from the studies... Increases in ductility begin at lower temperatures than recrystallization, and recrystallization begins at lower temperatures than grain growth. To reduce case cracks an increase in ductility is needed and recrystallization is desired, but grain growth is undesirable since the brass is more likely to develop cracks when grain size increases. The temperature versus ductility curves are relatively steep and getting a specific ductility is challenging and probably requires testing the results and knowing the history (%CW) of the brass. Excessive annealing (too hot for too long) will produce brass that's very ductile but grain size will be excessive. What's not clear is how (without expensive equipment or testing) to apply minutes/hours long anneal study results to a process that lasts only seconds (to allow annealing the neck and retaining body strength). It obviously is being done successfully by the case manufacturers. As one who only anneals to reduce neck splits, I'll continue with the drill/socket/torch method since it works for that purpose. I'll probably consider reducing the flame and time somewhat so as to avoid grain growth. At the other end, I can sorta tell if the ductility is not sufficiently high when the neck expander is drawn through the neck during sizing. |
August 21, 2019, 04:24 PM | #61 | |
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Ok, no more arguing, enjoy your alternative facts.
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August 21, 2019, 05:45 PM | #62 | ||
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So far the only expert you have quoted is some guy who used to post here that bought and sold military surplus brass out of his barn shed. I remember when he then bought a $50 electronic microscope that plugged into his cellphone from Amazon and declared himself a expert on annealing. now who is using alternative facts? By the way I agree with BBarn, that old drill and socket seems to be the best and cheapest way to soften the neck and shoulder a bit
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August 21, 2019, 10:30 PM | #63 |
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I bought the torch
Sorry if I am breaking up whatever you guys are still arguing about. Big thanks to Unclenick for his informed and detailed input.
I bought the torch today. Brought it home, found a bottle (of propane), read the instructions, assembled for my desired set-up and lit it up. So far, so good. Then I put a "test" case in pliers, and applied heat. #1 - The flame from that wrap-around burner is floppy and not well directed. I found myself holding it in a fireball. #2 - Heat adjustment goes from almost-out to roaring-inferno in less than 1/4 turn of the small knob. #3 - I gave it a few seconds of good flame, applied to the shoulder area, watched for any sign, and pulled it out when I saw any change. That was at 2 seconds. I pulled the brass out of the flame and it had a medium glow visible for a few seconds in average home lighting, evenly distributed over neck, shoulder, and a bit down the side 1/6". Right on target! This was without any templaq. I have not put this brass in any die post heating, but will later. That particular case will never be loaded. It was the first one I tried to convert to 7mm-08 (and only got 1/8" down the neck). I will do more tests, on different lots of brass, over the next few days, and post a detailed report at that time. My primary purpose here is to make my brass more malleable for working in dies. My only conclusion thus far is that the temperature/heat output will not be easy to adjust, and visual indicators or Templaq will be needed.
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August 22, 2019, 07:22 AM | #64 |
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Marco I tried a "turbo" propane once, for one case and yeah too much flame. The best tip I have found is the basic pencil tip. Templaq is a the best bet for temp control but the problem is you have to put it in a area not in direct flame, ie the inside of the neck. Can be a pain.
Hornady used to make a kit that included 450 Templaq and the recommended putting it just below the shoulder on the case body itself and not to get the flame directly on it https://www.midwayusa.com/product/1012738899?pid=360902 Not really a argument, just a discussion on whether the the brass changes as soon as it hits 750 in your garage or behaves like it does in laboratory conditions and requires minutes at that temperature to soften. In other words trying to answer the question you asked about the proper temperature. Back of the gunshop wisdom says as soon as it hits 750. Me I tend to believe the metallurgy lab numbers. Let us know how the wildcatting of the case works out. I am thinking of rebarreling one of my rifle to 6 Dasher later this year or early next which means making your own cases from 6BR brass
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August 22, 2019, 11:55 AM | #65 |
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Actually, I am not wildcatting (not yet anyway). 7mm-08 was a wildcat at one time, but I bought a Savage Axis II chambered in 7mm-08. That cartridge is simply a 308 case necked down in a 7mm-08 die.
I am a big believer in using military cartridges (7.62, 5.56, 9mm, 45 ACP). Speaking of cartridge conversions, you "CAN" make 45 ACP brass from 7.62 brass. The head is the same, and uses the same shellholder. That 7.62 to 45 conversion would require reaming the former body to accept 45 bullets (brass is thicker). I have no plans to do so, because handgun brass is cheap. While at HFT, I also bought a propane adapter, which you can use to refill propane bottles from your BBQ or RV tank. I had to ask because it was not with the torches. They led me to a different aisle (household/RV stuff). It was $18 roughly. What I would rather have is a direct connect to the bigger tank.
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............ Last edited by Marco Califo; August 22, 2019 at 10:47 PM. Reason: Propane adapter added |
August 22, 2019, 01:48 PM | #66 |
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Maco: A big difference make is to get roatary motion.
When I tried the torch method I chucked up a deep well socket that held the case right (forget what size) Worked ok. The Up Scale torch setups have rotary plates that turned the case while in the flame (and the rest of the time) Your biggest issue is to get the heat down to the base and soften that up - you can paint the templiaq below the shoulder to confirm its not doing that. I felt the socket also acted as a heat sink on the head to help avoid that.
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August 22, 2019, 02:35 PM | #67 |
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Rc20, the point of this thread has been the wrap around burner. There is no need to rotate, and when I tried it last night the glow was perfectly even. No, I do not believe rotation with this burner will have any effect and is not needed.
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August 22, 2019, 03:03 PM | #68 | |
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or similar
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August 22, 2019, 03:25 PM | #69 |
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Hey, good recommendation. Mine is on the way, and I can return the bottle filler thing. And I net $10 back. That one is less expensive than a USB cable.
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............ Last edited by Marco Califo; August 22, 2019 at 09:29 PM. Reason: not my typo |
August 23, 2019, 09:12 AM | #70 | |
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That had to be 24 + years ago, nothing has changed, there is nothing I can do to improve on my cheap design and nothing has changed about the way these threads end after 4 pages. F. Guffey |
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August 23, 2019, 12:38 PM | #71 | |
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August 23, 2019, 01:27 PM | #72 |
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if I had access to a machine shop again I would play with something that used 2 or 3 pinpoint jet burners and a copper heatsink that held the case just below the shoulder. I am fairly sure that I could make a ring burner that would be "delicate" enough using a regulator and very small jets. The heat sink would capture any heat traveling past the shoulder and help protect the case body from being softened too far down. Heatsinks could be spring loaded to accommodate various size cases and come in various sizes. If I decide to go to 6 Dasher next year I might rig something up before case reforming.
With that in mind last night I experimented with what happens when you heat the neck to cherry red. Ruins the case of course so if you try it yourself destroy the case afterward because the body will be too soft. In regard to the neck though I heated the neck to bright red, FL resized it with a which compressed the neck .003 smaller than the fired neck size, measured the OD of the sized neck and repeatedly seated a bullet using a arbor press and a Wilson inline seating die then pulled it using a collet style neck puller and remeasured the neck. Five repetitions and the neck was still the same OD. Before pulling it with the collet puller for the last time I grabbed the bullet with a pair of needle nose in one hand and the case in the other and could not get it to budge. Just one case but anyone with a collet puller and a sacrificial case can take a old case and try it themselves, but do not reload the case with a over softened body. The metallurgy labs seem to be right on this one. The elasticity of annealed brass is the same as the elasticity of work hardened brass
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