24hourcampfire.com
24hourcampfire.com
Previous Thread
Next Thread
Print Thread
Hop To
#52168 02/15/02
Joined: Feb 2001
Posts: 8,515
Campfire Outfitter
OP Offline
Campfire Outfitter
Joined: Feb 2001
Posts: 8,515
Ken, What is your opinion on cyro (sp?) treatment (or deep freezing in layman terms) I've read a lot of pros with few cons. Wondering what your thoughts are. Thanks in advance vbshootinrange.

BP-B2

Joined: Jan 2002
Posts: 64
Campfire Greenhorn
Offline
Campfire Greenhorn
Joined: Jan 2002
Posts: 64
Obviously I am not Ken, however, I have used the process several times and I have researched the science behind the treatment. Cryogenic treatment has been around for several decades. It was developed specifically for industrial cutting and grinding tools. It was discovered that cryoed metals possessed greater wear resistence and it also increased the life of the tool (considerable operational savings were the result). In short order, the process was adapted to all types of metal objects from musical instruments, softball (metal) bats, racing engines, gun barrels, and anything else you can think of.
<br>
<br>Here is the science behind the process - Cryogenic treatment is designed to take ferrous and non-ferrous metals down - 300 degrees F at a controlled and incremental rate. Once the temperature is reached it is maintained for 18 to 36 hours and then the part being treated is slowly returned to room temperature. The process is designed to complete the austenite to martensite transformation that occurs during heat treatment in steel alloys. Austenite is the soft carbon within metal and the martensite is the smaller and stronger carbon molecule which comprises steel. The concept is, if you can covert most or all of the carbon atoms from austenite to martensite, then the metal becomes more dimensionally stable, stronger, and more wear resistant.
<br>
<br>That is the science. Now, as with all basic scientific principles, they sometimes do not guarantee results in complicated models like gun barrels. There is no question that converting austenite to martensite is a good thing but it does not necessarily translate to a more accurate wonder gun. I have had four barrels treated and here are my observations about the process:
<br>
<br>1. The time to cryo a barrel is before it is rifled and contoured. The barrel should then be retreated before the chamber is cut.
<br>
<br>2. The end result is a more heat tolerant (stable) barrel. For varmint, bench rest, and high volume shooters, heat stability is a big deal. Cryoed barrels �seem� to hold zero better over a wider range of operating temperatures.
<br>
<br>3. Many report that cryoed barrels are more ware resistant and seem to accurately shoot 30% to 50% more total rounds before the barrel is shot out. Throat erosion is a measurable benchmark for determining wear resistence.
<br>
<br>4. Machinists who cut chambers report that a cryoed barrel cuts substantially better than non-cryoed barrels. Many state that they can feel the difference while cutting.
<br>
<br>5. My cryoed barrels clean noticeable easier than my non-treated barrels from the same manufacturer.
<br>
<br>6. It would be difficult to prove that cryoed barrels are more accurate than non-treated barrels.
<br>
<br>7. Way down on the list of possibilities is the very remote chance that by relieving inherent stress within the barrel, you can cause some very minor warping. If a stressed barrel was cut straight to begin with (95% of barrels are not straight), by relieving the stress you can alter the bore. This has never been proven, however, the possibility exists in principle.
<br>
<br>My opinion is that the process may refine some accuracy traits within your gun, however, it is not a magic treatment and will not turn a crappy barrel into a bench rest gun. If you start with a premium barrel, there are some desirable benefits. Considering the low cost of treatment today, it is worth giving it a try.
<br>
<br>For factory barrels you may well be wasting your money. This is because you are treating the barrel after the fact (cutting & chambering). You may see some improvements in a factory barrel, however, the greatest gains are to be made are before cutting begins. At the end of the day, I have never heard any report about damaging your gun by treating the barrel. There doesn't seem to be any real downside.

Joined: Dec 2000
Posts: 29,348
Campfire Ranger
Offline
Campfire Ranger
Joined: Dec 2000
Posts: 29,348
ZD answered your query better than I could've.


"Good enough" isn't.

Always take your responsibilities seriously but never yourself.



















Joined: Oct 2000
Posts: 2
New Member
Offline
New Member
Joined: Oct 2000
Posts: 2
My two cents worth .
<br>I am not a metallurgist but I find that Krieger Barrels Inc. is very high on "cryo " treating their products. If you buy one of their fine barrels you will buy a cryo'd barrel . They treat them once for themselves , before they do any machining . I am sure that they would not have setup an inhouse cryo treatment facility if their metallurgists weren't positive about the benifits of this process .
<br>They also offer to treat the barrel again at finish for an extra charge of $40.00 . the first treatment is included in the barrel price .
<br>I think this says alot in favor of "cryo" treatment .
<br>
<br>Below is Krieger's url
<br>
<br>http://www.kriegerbarrels.com

Joined: Jan 2001
Posts: 2,181
Campfire Regular
Offline
Campfire Regular
Joined: Jan 2001
Posts: 2,181
Guess who is using Krieger barrels in their rifles now...Weatherby!


You learn something new everyday whether you want to or not.
IC B2

Joined: Jan 2001
Posts: 2,181
Campfire Regular
Offline
Campfire Regular
Joined: Jan 2001
Posts: 2,181
Sorry, those barrels on the Weatherby's are the Krieger after-market Criterion button-rifled barrels, not their excellent single-point cut barrels.


You learn something new everyday whether you want to or not.
Joined: Feb 2001
Posts: 24,239
Campfire Ranger
Offline
Campfire Ranger
Joined: Feb 2001
Posts: 24,239
Here is a cheap way to deep freeze your barrel:
<br>
<br>Make friends with someone in Borger TX.This is not difficult since anyone stuck in Borger needs all the friends he can get.
<br>
<br>Ask him to find a morning tour derrickman for you.This wont be difficult since the only reason to be in Borger is to be working in the oil patch.
<br>
<br>Ask the derrickman to take the barrel up to the board with him next time they have a trip in Jan.That 's easy since the majority of trips in Jan. in Borger will be on morning tour.
<br>
<br>Make sure he brings it down after a couple hours.You dont want it to get too cold.


Never holler whoa or look back in a tight place
Joined: Mar 2002
Posts: 38
Campfire Greenhorn
Offline
Campfire Greenhorn
Joined: Mar 2002
Posts: 38
FWIW I do have a degree in metallurgy, as well as experience in firearms manufacture. You might have to bear with me a bit here, but here's my view:
<br>
<br>Quenching and tempering of Steels
<br>
<br>By way of background, in the typical medium-carbon steel after annealing the structure is made up of ferrite (essentially pure iron) and cementite (iron carbide). If you heat that structure enough, the structure transforms to austenite. Now, if you cool very slowly you're back where you started as the austenite transforms back again to ferrite and cementite (though you may have relieved any internal stresses - this is annealing).
<br>
<br>If, however, you cool very quickly (quench), the ferrite and cementite don't have time to form, so what you get is a structure called martensite, in which very fine needles of carbide are finely dispersed through a ferritic matrix.
<br>
<br>This structure is glass-hard and very brittle, and not much use unless you carry out controlled heating to a temperature below the austenite transformation to temper the structure.
<br>
<br>The role of cryogenic quenching
<br>
<br>In some alloy steels the transformation from austenite to martensite is not complete at room temperature. The result is that grains of austenite are retained in the martensite. This can be a problem in that grains of austenite are softer than the martensite around them, leading to "soft spots" and difficulties with machining, as well as the fact that austenite has a different volume leading to distortion and retained stresses. It is a particular problem with certain die steels, and that is where cryogenic quenching was developed: to ensure that the transformation is complete. Note however that this is the mode of operation of cryo quenching: to solve problems with retained austenite in quenched and tempered steels.
<br>
<br>Cryo and rifle barrels
<br>
<br>It is unlikely that cryogenic quenching has any real effect on rifle barrels. Generally speaking these are not used in the quenched and tempered condition, but instead are typically subject to varying degrees of cold forming (hammer forging, and to a lesser extent button rifling) or else drilled and broached from bar stock, and then normalised.
<br>
<br>Ironically, if cryogenic quenching did have an effect on a finished barrel, it would probaly show up as distortion, due to the volume change as any retained austenite transformed to martensite.
<br>
<br>
<br>
<br>
<br>

Joined: Jun 2001
Posts: 3,306
Campfire Tracker
Offline
Campfire Tracker
Joined: Jun 2001
Posts: 3,306
Holy Cow Zerodrift,
<br>I thought it was at least illegal to austenite in order to martensite transformation in public. Wasn't that something that your mother told you never to do or else hair would grow on the palms of your hands?


Rolly
Joined: Jan 2002
Posts: 64
Campfire Greenhorn
Offline
Campfire Greenhorn
Joined: Jan 2002
Posts: 64
Rolly - Your gonna hafta speak up, I'm blind. [Linked Image]

IC B3

Joined: Mar 2002
Posts: 38
Campfire Greenhorn
Offline
Campfire Greenhorn
Joined: Mar 2002
Posts: 38
Just a couple more points
<br>
<br>Austenite isn't always a bad thing:
<br>
<br>Some alloys are selected because they are austentic at room temperature. A very common example is the range of stainless steels of about 18/8 Ni/Cr, such as 304. These austenitic steels typically have high formability as well as being nonmagnetic, and are very common in such things as kitchen sinks.
<br>
<br>Cryo quenching does have some uses:
<br>
<br>It is a valuable adjunct to manufacture of dies and tools in certain alloys, particularly where hardenability is questionable and/or the austenite-martensite temperature is low. Just because it has application here though, it doesn't necessarily follow that it is a panacea. It is a bit like saying to yourself: hmm, jet aircraft have afterburners to go faster- I should get one for the car!
<br>
<br>All this stuff is relevant only to steels - and not even all steels:
<br>
<br>The use of cryo quenching is for driving to completion a phase transformation seen in steels, over a particular range of compositon. This is irrelevant in non-ferrous metals, where changes in propoerties are made by other means such as work-hardening or precipitation hardening.
<br>
<br>Ii still seems to me that cryo quenching of barrel steels is a triumph of marketing, but that gene's idea of talking someone into putting your barrel in the snow has about as much to recommend it.

Joined: Jun 2001
Posts: 3,306
Campfire Tracker
Offline
Campfire Tracker
Joined: Jun 2001
Posts: 3,306
Whew, are we done with this technical metalurgical stuff now? Plllllleeeeaaaassseeee !


Rolly
Joined: Mar 2002
Posts: 38
Campfire Greenhorn
Offline
Campfire Greenhorn
Joined: Mar 2002
Posts: 38
Shooting's about details, and forums like this are about sharing knowledge.
<br>
<br>But hey, no one's forcing anyone to learn anything.

Joined: Jan 2001
Posts: 2,181
Campfire Regular
Offline
Campfire Regular
Joined: Jan 2001
Posts: 2,181
Hey, when someone asks a question why wouldn't you expect an answer? Thanks Daniel!


You learn something new everyday whether you want to or not.
Joined: Apr 2002
Posts: 22
SCW Offline
New Member
Offline
New Member
Joined: Apr 2002
Posts: 22
Daniel,
<br>What do you think accounts for the improvements noted by users or cryo'ed berrels? It seems that possibly the effect on these other applications is greater than the effect on gun barrels, but it still may have a positive effect. This is a totally uneducated conjecture, just curious.
<br>Shane

Joined: Apr 2002
Posts: 670
Campfire Regular
Offline
Campfire Regular
Joined: Apr 2002
Posts: 670
Daniel:
<br>
<br>I particularly appreciated your metallurgical explanations. And I also appreciated Zero Drifts input and opinions.
<br>
<br>Over time I have heard from many who have sent their rifles out for cryo-treatment and I have observed that not all companies do it the same way. Some are cheap "quickie" treatments. The shooters have reported a spectrum of results from one end to the other.
<br>
<br>So far as your explanations went, they dealt with the internal metallurgical transformation. However, there seems to be more to the story. Have a look at the explanation at this site then click on "customer comments" and view the targets and groups.
<br>
<br>This can't all be "sales hype". The references can be checked. Considering the source, I seriously doubt that he would deliberately perpetrate a fraudulent misrepresentation and put it on the internet.
<br>
<br>There has to be something to the story. The question is: Just exactly what is it?
<br>
<br>http://www.z-hat.com/Cryo.htm
<br>
<br>
<br>

Joined: Feb 2002
Posts: 4,302
Campfire Tracker
Online Content
Campfire Tracker
Joined: Feb 2002
Posts: 4,302
VB
<br> I have built several rifles using cryo treated barrels. The engineers here know a lot more about the structure of steel than I do. I cant tell any defference in how the steel machines. I do use only carbide reamers so that may make some difference. I looked over some of my notes and I cant see any difference in fouling or group size. I think if you start with a match grade barrel cryo may not be necessary.
<br>Charlie Sisk


The data and opinions contained in these posts are the results of experiences with my equipment. NO CONCLUSIONS SHOULD BE DRAWN FROM ANY DATA PRESENTED, DO NOT, UNDER ANY CIRCUMSTANCES, ATTEMPT TO REPLICATE THESE RESULTSj
Joined: Feb 2001
Posts: 8,515
Campfire Outfitter
OP Offline
Campfire Outfitter
Joined: Feb 2001
Posts: 8,515
Charlie; Thanks for the reply. Most of the tech. stuff is over my head. You put it in layman terms I can understand.
<br> I'm having a 600 action barreled by Pac-Nor and couldn't decide on freezing or not.
<br> I'm thinking my super match will be just fine without freezing.
<br> Got till about mid June 'till I get my 25-284 together. will post results when finished.
<br> Thanks for the replys! vbshootinrange.

Joined: Mar 2002
Posts: 38
Campfire Greenhorn
Offline
Campfire Greenhorn
Joined: Mar 2002
Posts: 38
G'day SCW
<br>
<br>The thing about the cryo treatment of rifle barrels is that it is never performed in isolation, and is rarely tested in any sort of scientific manner.
<br>
<br>Taking the first point for example, at minimum cryo treatment will involve stripping and thoroughly cleaning the barreled action, and more or less careful reassembly, checking screw tensions etc. That alone will usually make a positive difference.
<br>
<br>It doesn't always stop there either: how many times, in a report on cryo treatment, was there also a bedding job, action truing, trigger adjustment etc as part of the package?
<br>
<br>You then have the before and after testing, which typically doesn't compare apples with apples nor involve any statistically significant number of tests. A couple of groups doesn't really prove much after all, particularly if other aspects of the test aren't replicated.
<br>
<br>I s'pose the final one is human nature: people will convince themselves that something works and if you really believe in it you'll probably shoot better. People will even reject or discount results which don't accord with their expectations, perhaps ignoring a few poor groups or "fliers" for example.
<br>
<br>
<br>
<br>


Moderated by  RickBin 

Link Copied to Clipboard
YB23

Who's Online Now
680 members (1Akshooter, 1beaver_shooter, 10gaugemag, 17CalFan, 12344mag, 74 invisible), 2,984 guests, and 1,429 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums81
Topics1,187,672
Posts18,399,514
Members73,817
Most Online11,491
Jul 7th, 2023


 







Fish & Game Departments | Solunar Tables | Mission Statement | Privacy Policy | Contact Us | DMCA
Hunting | Fishing | Camping | Backpacking | Reloading | Campfire Forums | Gear Shop
Copyright © 2000-2024 24hourcampfire.com, Inc. All Rights Reserved.
Powered by UBB.threads™ PHP Forum Software 7.7.5
(Release build 20201027)
Responsive Width:

PHP: 7.3.33 Page Time: 0.093s Queries: 13 (0.003s) Memory: 0.8849 MB (Peak: 1.0208 MB) Data Comp: Zlib Server Time: 2024-03-28 20:51:33 UTC
Valid HTML 5 and Valid CSS