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August 18, 2013, 12:02 PM | #26 | |
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Quote:
I do heat to a glow then tip over into the water pan. I don't believe I have ever annealed a batch of brass twice. And, I get dozens of reloads from my brass. Mostly .44 mag. and 30-06. |
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August 18, 2013, 04:02 PM | #27 |
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Yes. I should have said heating it to red hot may weaken your brass, but you can actually do it if you don't expose the brass to that temperature for too long.
Fred Barker's article was where I saw the comment on weakening. Subsequently, I've encountered a number of folks who report annealing every three or four load cycles and who all heat to red heat. I assume they feel the need to repeat annealing so frequently because of failures at just beyond that interval. In your case I am guessing since I haven't seen you anneal, but if the necks hit the water still red, the water may in fact be helping you stay inside a necessary time window. The process is actually both time and temperature dependent. The higher the temperature, the faster things happen and the sooner you can exceed an acceptable heat exposure. If you look at the chart below, which is for 1 hour exposure, you see that 700°F is high enough to weaken brass and grow its grain size unnecessarily over that one hour time period, yet one of Barker's described methods relies on a number of seconds exposure in molten lead alloy at 700°-750°F. Why isn't that too hot, as it is in the chart? The brass just isn't exposed to it long enough for that to be too hot. So, the best answer really isn't to say 'never let your brass get to a red glow or to this or that temperature', but rather would be to provide some kind of chart of exposure time minimum and maximum vs temperature. I have not been able to find such information published. It would take a lot of work to verify the possible combinations. All that's known for sure is that avoiding overheating always works, and that's why Barker published the candle and lead methods as he did.
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August 19, 2013, 07:40 AM | #28 |
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One hour?
Mine glows for seconds before hitting the water. Whatever. It works for me. |
August 19, 2013, 09:19 AM | #29 |
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Try knocking them in with a stick as soon as you can detect a glow (normal light). See if your bullet pull improves. If so, it should be reflected by slightly higher and more uniform velocity over the chronograph. If you don't see an improvement or, worse, if case life seems less extended, then in your lighting conditions you need longer exposure at that glow level.
If you work in total dark, you may have noticed you can then detect glow even in your lead melt, and at that glow level it can take several seconds of exposure to finish stress relief of the case, depending on the exact numbers and heat transfer rate (varies with fuel for flame). This is one of the big problems with glow as a temperature indicator. Like optical illusions where changing the background around a color patch changes the apparent color of the patch, differences in lighting conditions can cause you to think you see the same color of glow as under other lighting conditions when there is actually up to several hundred degrees difference in pyrometer temperature. Going from bright light to low daylight caused the pre-pyrometer tempering of early Springfield receivers to be irregular. I think Hatcher said over 300°F actual temperature difference at quench occurred.
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