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12L14 steel strength
- Thread starter Col. Batguano
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Elongation is the percentage of its length that something will stretch before it breaks.
During tensile testing to see how much stress (force) it takes to break a material, the material rarely stays the same length. As the load increases, the material stretches, like a rubber band would.
Sooner or later, the material breaks. The amount of stress needed to break it gives us the tensile strength value. The percentage of length it grew gives us the elongation percentage value.
A material that is ductile will stretch or change shape because its elongation value is high.
A material that is brittle will stretch or change shape very little because its elongation value is low.
The other material property that is important is the Yield strength.
When a material is subjected to stress (force) it will usually stretch or deform to some degree.
As the stress is increased the material will stretch or deform more.
There is a limit to how much force it can take though before it becomes permanently stretched or deformed.
For instance you can bend a piece of wire by applying a force (stress) to the side of it.
Up to a point, the wire will "spring back" to its original shape and size. If too much pressure is applied the greater stress (force) will bend the sire and it will only partially spring back.
The amount of stress (force) needed to reach this point of no return is the Yield strength value and in the case of the permanently bent wire, that yield strength has been exceeded.
Usually, materials with good elongation properties yield long before they break (reach their tensile strength limit).
Materials with poor elongation properties often show little sign of yielding before they break.
An odd thing about most materials.
Repeated applications of stress (force) tends to make them more brittle. Their elongation value is reduced slightly with each application.
If their elongation value is high it takes a long time for this to cause a problem.
If the elongation value is low it can cause problems fairly rapidly.
The closer the stress value is to the yield strength and tensile strength of the material, the more rapidly this embrittlement occurs.
This is one of the reasons a "safety factor" is always used in designing a gun barrels wall thickness.
Fortunately for us, the actual stresses in our barrels when firing a muzzleloader are far below the yield and tensile strength of the weaker carbon steels and their elongation is high enough that shooting them doesn't create a problem by changing the barrels elongation value.
There is no doubt about it though, if a materials elongation value is higher, there is less likelihood of the barrel failing.
During tensile testing to see how much stress (force) it takes to break a material, the material rarely stays the same length. As the load increases, the material stretches, like a rubber band would.
Sooner or later, the material breaks. The amount of stress needed to break it gives us the tensile strength value. The percentage of length it grew gives us the elongation percentage value.
A material that is ductile will stretch or change shape because its elongation value is high.
A material that is brittle will stretch or change shape very little because its elongation value is low.
The other material property that is important is the Yield strength.
When a material is subjected to stress (force) it will usually stretch or deform to some degree.
As the stress is increased the material will stretch or deform more.
There is a limit to how much force it can take though before it becomes permanently stretched or deformed.
For instance you can bend a piece of wire by applying a force (stress) to the side of it.
Up to a point, the wire will "spring back" to its original shape and size. If too much pressure is applied the greater stress (force) will bend the sire and it will only partially spring back.
The amount of stress (force) needed to reach this point of no return is the Yield strength value and in the case of the permanently bent wire, that yield strength has been exceeded.
Usually, materials with good elongation properties yield long before they break (reach their tensile strength limit).
Materials with poor elongation properties often show little sign of yielding before they break.
An odd thing about most materials.
Repeated applications of stress (force) tends to make them more brittle. Their elongation value is reduced slightly with each application.
If their elongation value is high it takes a long time for this to cause a problem.
If the elongation value is low it can cause problems fairly rapidly.
The closer the stress value is to the yield strength and tensile strength of the material, the more rapidly this embrittlement occurs.
This is one of the reasons a "safety factor" is always used in designing a gun barrels wall thickness.
Fortunately for us, the actual stresses in our barrels when firing a muzzleloader are far below the yield and tensile strength of the weaker carbon steels and their elongation is high enough that shooting them doesn't create a problem by changing the barrels elongation value.
There is no doubt about it though, if a materials elongation value is higher, there is less likelihood of the barrel failing.
galamb
58 Cal.
Even I "kinda sorta" understood that.
At the end of the day, all the science/engineering aside, for many "decades" 12L14, when not mis-treated or mis-used has proven to be more than adequate and safe for all levels of black powder use.
It is currently used by Rice, Getz, FCI (Charlie Burton), Oregon, Colerain, Long Hammock and a few others that escape my mind at the moment (although the Cuban Rum I'm drinking may have something to do with that as well) :hmm:
If you are "averse" to 12L14 then you do have a couple of options.
As noted, Green Mountain uses 1134 in their (now) somewhat limited offerings.
Jason at Rice will build with 4140 if you have a fatter wallet (starts at $300 for his only "production barrel built with 4140" everything else is "custom").
I'm sure just about any of the barrel makers would source another type of steel if you really wanted it and were willing to pay (and wait).
At the end of the day, all the science/engineering aside, for many "decades" 12L14, when not mis-treated or mis-used has proven to be more than adequate and safe for all levels of black powder use.
It is currently used by Rice, Getz, FCI (Charlie Burton), Oregon, Colerain, Long Hammock and a few others that escape my mind at the moment (although the Cuban Rum I'm drinking may have something to do with that as well) :hmm:
If you are "averse" to 12L14 then you do have a couple of options.
As noted, Green Mountain uses 1134 in their (now) somewhat limited offerings.
Jason at Rice will build with 4140 if you have a fatter wallet (starts at $300 for his only "production barrel built with 4140" everything else is "custom").
I'm sure just about any of the barrel makers would source another type of steel if you really wanted it and were willing to pay (and wait).
Doug Lykins
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Wow! A very detailed and thorough answer and I thank you. I'm missing something here though. 4140 chrome moly barrel blanks built for high pressure centerfire rifles aren't all that much more expensive than ML barrel blanks, considering the overall cost & effort to build a good ML rifle. If I honestly thought I were getting a better barrel/rifle, paying $300 instead of $160 for a blank is no big deal.
On the other hand, perhaps there is no advantage to the higher quality steel, a case of overkill?
On the other hand, perhaps there is no advantage to the higher quality steel, a case of overkill?
A) Overkill. B) much more difficult to machine. Slower, harder on every tool from drills to reamers to lathe tools or mill bits. Tools won't last as long with 4140.
IMO, if you were going to shoot the metal jacketed bullets we can't talk about here all the time, the 4130 4140 or a 4340 material might be worth while just because it will wear longer.
Shooting lead bullets or patched balls or even paper patched bullets protects the barrel from the wear that those things will cause. This makes the 4130, 4140 or other chrome moly materials a waste of money for our type of shooting.
Shooting lead bullets or patched balls or even paper patched bullets protects the barrel from the wear that those things will cause. This makes the 4130, 4140 or other chrome moly materials a waste of money for our type of shooting.
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Well, I partially agree with what you have said about barrel steel Zonie.
Not being a metallurgist I have to rely on the information gotten from those who are.
I totally agree that how a metal is formed( cold drawn or hot rolled) is more important than the make up of any reasonably tough and ductile machine application steel alloy.
However I feel that ductility and tensile testing is not a very good measure of an alloys ability to withstand shock loads especially radially or across the grain as happens in gun barrel application.
The problem with tensile testing is that it does not measure this stress accurately. Tensile test loading is done slowly with bars that can exhibit brittleness under shock load and ductility under tensile testing.
Many of the earlier barrels were of 12L14 that were cold rolled because it machines so beautifully but this steel is brittle under radial shock load at 70 degree F. This is known as the ductile to brittle impact transition temperature.
The proper test for barrel steel toughness that takes into account shock loading, temperature and barrel cut outs (dovetail slots) is the notched bar impact test. In these tests results are given in foot pounds of energy absorbed in breaking the bar through the notch quickly.
There are two, Charpy and Izod. The two methods are different only in the shape of the test notch.
Anything below 15ft lbs is considered not tough enough for structural application.Cold rolled 12L14 shows a result of about 5 ft lbs. on the shock test.
As was pointed out 12L14 hot rolled is much better but still not as good as 1137 hot rolled ( I mistakenly called it 1134) has an Izod rating of 47. A rating of 40 is considered good.
It seems unfair to compare cold rolled 12L14 with hot rolled 1137 except that this was what the early barrels were made of.
I need to verify what is going on in the industry currently but I suspect many barrel makers are still using cold rolled 12L14 and I believe GM is using hot rolled 1137.
As I said I need to verify this with GM but that has been my understanding and the reason I feel 1137 is a much better way to go. One mans opinion. Mike D.
Not being a metallurgist I have to rely on the information gotten from those who are.
I totally agree that how a metal is formed( cold drawn or hot rolled) is more important than the make up of any reasonably tough and ductile machine application steel alloy.
However I feel that ductility and tensile testing is not a very good measure of an alloys ability to withstand shock loads especially radially or across the grain as happens in gun barrel application.
The problem with tensile testing is that it does not measure this stress accurately. Tensile test loading is done slowly with bars that can exhibit brittleness under shock load and ductility under tensile testing.
Many of the earlier barrels were of 12L14 that were cold rolled because it machines so beautifully but this steel is brittle under radial shock load at 70 degree F. This is known as the ductile to brittle impact transition temperature.
The proper test for barrel steel toughness that takes into account shock loading, temperature and barrel cut outs (dovetail slots) is the notched bar impact test. In these tests results are given in foot pounds of energy absorbed in breaking the bar through the notch quickly.
There are two, Charpy and Izod. The two methods are different only in the shape of the test notch.
Anything below 15ft lbs is considered not tough enough for structural application.Cold rolled 12L14 shows a result of about 5 ft lbs. on the shock test.
As was pointed out 12L14 hot rolled is much better but still not as good as 1137 hot rolled ( I mistakenly called it 1134) has an Izod rating of 47. A rating of 40 is considered good.
It seems unfair to compare cold rolled 12L14 with hot rolled 1137 except that this was what the early barrels were made of.
I need to verify what is going on in the industry currently but I suspect many barrel makers are still using cold rolled 12L14 and I believe GM is using hot rolled 1137.
As I said I need to verify this with GM but that has been my understanding and the reason I feel 1137 is a much better way to go. One mans opinion. Mike D.
jamesthomas
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Paying $300.00 vs. 160.00 I'll pay the $160.00 every time, that extra $140.00 will pay for buttplates, triggers, trigger guards, and ramrod pipes. It will also pay for good lock, or a nice upgrade on your wood. 12L14 is a very good steel for a muzzleloader shooting patched roundballs. BUT and it can be a an important "BUT" is that I would not use it using a conical with a heavy charge behind it in a straight barrel. I called TVM about using the 200grn. R.E.A.L. conical that member Roundball uses in his .40 cal. and they told me no uncertain terms to NEVER SHOOT that round in my barrel which is a 36 inch 13/16 .40 caliber Mark DeHass barrel. I'm guessing that they consider the breech thickness not up to the pressure a conical will produce.
Doug Lykins
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So, the modern MLs, in-lines etc. logically do not use the same steel,(12L14), in that conical or even jacketed bullets are normally used.
galamb
58 Cal.
Knight barrels are made by GM, so 1137 is "probable".
In a 2010 article I have, at the point after Knight stopped making their own barrels, it notes that T/C and Savage were using 1137 in their "non-sidelock" rifles that shoot plastic wrapped bullets that offered "standard" barrels.
The stainless barrels, fluted, by Bergara (found on CVA offerings - and probably Traditions) are made with 416 stainless.
I have no idea what they are making the moly lined (chrome) barrels from, but 4140 would be my guess.
All of which is immaterial to us roundball shooters whose 12L14's will outlive all but the most prolific shooters - and then they will simply be "shot out" and not "dangerous/damaged".
Ok, I get the argument, and yes, I could pull my boat with a 1 ton dually that has a diesel engine, but my 2WD 1/2 ton small 8 gas wagon does it "safely and economically" in comparison.
In a 2010 article I have, at the point after Knight stopped making their own barrels, it notes that T/C and Savage were using 1137 in their "non-sidelock" rifles that shoot plastic wrapped bullets that offered "standard" barrels.
The stainless barrels, fluted, by Bergara (found on CVA offerings - and probably Traditions) are made with 416 stainless.
I have no idea what they are making the moly lined (chrome) barrels from, but 4140 would be my guess.
All of which is immaterial to us roundball shooters whose 12L14's will outlive all but the most prolific shooters - and then they will simply be "shot out" and not "dangerous/damaged".
Ok, I get the argument, and yes, I could pull my boat with a 1 ton dually that has a diesel engine, but my 2WD 1/2 ton small 8 gas wagon does it "safely and economically" in comparison.
Is this thread still going on? 
Fuggitit...the reason 12L14 barrels aren't around anymore is because they all blew up. :shocked2: :wink: :blah:
Fuggitit...the reason 12L14 barrels aren't around anymore is because they all blew up. :shocked2: :wink: :blah:
Reply to Topic--
I remember some years ago, someone was doing tests on
12L14 steel. I think he was from Montana/Orion bbls.
The only way he could get a bbl to fail, as I remember,
was to ram the ball close to but slightly away from the powder charge.
Doesn't a ball in this position increase the pressure a lot more than a ball short started near the muzzle?
I remember some years ago, someone was doing tests on
12L14 steel. I think he was from Montana/Orion bbls.
The only way he could get a bbl to fail, as I remember,
was to ram the ball close to but slightly away from the powder charge.
Doesn't a ball in this position increase the pressure a lot more than a ball short started near the muzzle?
galamb
58 Cal.
I don't get the point - won't any barrel fail if there is an "obstruction" in the barrel - be it dirt, a mis-loaded projectile etc.
While modern cartridge rifles are a little more "idiot proof" and can withstand a lot more careless handling - in that, they kinda load themselves as long as you get the cartridge in the magazine correctly, the barrel will still split open like a banana if it's obstructed.
In our sport where we are accomplishing the "loading" with a number of "mechanical steps" that must be done properly is a specific order and "reasonable care" must be taken AND attention to detail is important, there is a number of instances in that procedure that make it inherently dangerous - much more so than the cartridge rifle that is producing maybe 4 or 6 times as much pressure in the barrel.
If you do your part, that 12L14 barrel will do it's part and give you more than "safe" service.
If you figure you can do 40 over the speed limit because you have air bags, then maybe you shouldn't own a muzzle loader with 12L14 steel for the barrel....
While modern cartridge rifles are a little more "idiot proof" and can withstand a lot more careless handling - in that, they kinda load themselves as long as you get the cartridge in the magazine correctly, the barrel will still split open like a banana if it's obstructed.
In our sport where we are accomplishing the "loading" with a number of "mechanical steps" that must be done properly is a specific order and "reasonable care" must be taken AND attention to detail is important, there is a number of instances in that procedure that make it inherently dangerous - much more so than the cartridge rifle that is producing maybe 4 or 6 times as much pressure in the barrel.
If you do your part, that 12L14 barrel will do it's part and give you more than "safe" service.
If you figure you can do 40 over the speed limit because you have air bags, then maybe you shouldn't own a muzzle loader with 12L14 steel for the barrel....
"On the other hand, perhaps there is no advantage to the higher quality steel, a case of overkill?"
I saw this analogy regently.....You can make a toothbrush handle out of stainless steel. It will be stronger and more durable. It will have no advantage over the regular nylon handle in practical use. It will also cost much more.
There is no valid reason to make a toothbrush handle out of stainless, as there is no valid reason to use 4140 for a ML barrel. One could however, find somebody to make such a barrel if it would make them happy to address some imagined need.
It could be that leaded steel is being phased out by some barrel makers due to lead hysteria regulations.
I saw this analogy regently.....You can make a toothbrush handle out of stainless steel. It will be stronger and more durable. It will have no advantage over the regular nylon handle in practical use. It will also cost much more.
There is no valid reason to make a toothbrush handle out of stainless, as there is no valid reason to use 4140 for a ML barrel. One could however, find somebody to make such a barrel if it would make them happy to address some imagined need.
It could be that leaded steel is being phased out by some barrel makers due to lead hysteria regulations.
razorbritches
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That Sir is a pretty good analogy.
galamb
58 Cal.
I get that some guys/gals just sleep better at night if they are "over protected, over built" (pick your wording).
There will always be some that just feel uneasy with a 12L14 barrel.
That's probably why there are a couple of other options.
Ed Rayl builds with 8620. Green Mountain (as noted) uses 1137. Rice will build with 4140 (normally 12L14). Longhammock will build with 1137 (if you ask, normally uses 12L14). Jim McLemore uses/used 4150 (not sure if he is still building) and Sleepy Hills barrels (not taking orders/building at the moment) also used 4150.
Everyone else that I am aware of, even going back to old Douglas barrels etc have used or are using 12L14.
That is one mega-number of barrels out there made of 12L14.
Just about every one knows either first or second hand of a "smokeless" barrel that has "blown up".
Even though this forum is made up of "front stuffers", there is a very select few that have seen a "blowed up" 12L14 barrel that can be attributed to anything other than "an idiot with his/her finger on the trigger".
Shooting is potentially a dangerous sport. If you shoot within the limits of your equipment, then it's pretty much as safe as it needs to be (with lot's of extra "safety" built in).
There will always be some that just feel uneasy with a 12L14 barrel.
That's probably why there are a couple of other options.
Ed Rayl builds with 8620. Green Mountain (as noted) uses 1137. Rice will build with 4140 (normally 12L14). Longhammock will build with 1137 (if you ask, normally uses 12L14). Jim McLemore uses/used 4150 (not sure if he is still building) and Sleepy Hills barrels (not taking orders/building at the moment) also used 4150.
Everyone else that I am aware of, even going back to old Douglas barrels etc have used or are using 12L14.
That is one mega-number of barrels out there made of 12L14.
Just about every one knows either first or second hand of a "smokeless" barrel that has "blown up".
Even though this forum is made up of "front stuffers", there is a very select few that have seen a "blowed up" 12L14 barrel that can be attributed to anything other than "an idiot with his/her finger on the trigger".
Shooting is potentially a dangerous sport. If you shoot within the limits of your equipment, then it's pretty much as safe as it needs to be (with lot's of extra "safety" built in).
Col. Batguano
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Remember the premise for the OP. It wasn't "is 12L14 any good". That's largely accepted as ok., or else people wouldn't use it. The premise was; when using 12L14 within the confines of a normal pressure curve for normal BP loads, with normal powders, how thin can you go with the remaining steel under your dovetails before a catastrophic event occurs, using the 4x safety margin, and including the reinforcement of the dovetailed in and substituted metal adding at least SOME strength to the filed away area. Because that's how things work, I understand you don't need as much steel under your front sight as you do your rear one.
assumptions are being made that 12L14 can handle the shock and fatigue loads for a X defined period of time and X number of cycles.
While taking a barrel and trying to blow it up does show some strengths, it does not indicate what it is capable of doing after it has been subjected to shock and fatigue loads after a period of time.
We are introducing stress into the steel each time we fire it.
I deal a lot with cargo tanks in hazardous materials service, we see tanks failing due to the stresses put on those tanks. Most of these tanks are 25 years plus old, and they were just fine when they were first made, but years of stress is catching up to them.
I don't know if 12L14 steel in ML barrels will start to fail as they get older, time will tell us that.
I do know that there are better options and stronger steel than 12L14 for ML barrels, that is not disputed.
You have to balance the point of diminishing returns of safety. We can make a barrel that will never blow no matter what you do to it, but what does it weight, what is it made of and how much does it cost?
If like barrels are offered for a similar dollar amount and one is clearly stronger than the other why would you choose the weaker strength barrel?
I don't pull my boat with my ford ranger, but use my F-150 4 door 4x4. My Ranger will do it, but not the safest option I have.
Fleener
While taking a barrel and trying to blow it up does show some strengths, it does not indicate what it is capable of doing after it has been subjected to shock and fatigue loads after a period of time.
We are introducing stress into the steel each time we fire it.
I deal a lot with cargo tanks in hazardous materials service, we see tanks failing due to the stresses put on those tanks. Most of these tanks are 25 years plus old, and they were just fine when they were first made, but years of stress is catching up to them.
I don't know if 12L14 steel in ML barrels will start to fail as they get older, time will tell us that.
I do know that there are better options and stronger steel than 12L14 for ML barrels, that is not disputed.
You have to balance the point of diminishing returns of safety. We can make a barrel that will never blow no matter what you do to it, but what does it weight, what is it made of and how much does it cost?
If like barrels are offered for a similar dollar amount and one is clearly stronger than the other why would you choose the weaker strength barrel?
I don't pull my boat with my ford ranger, but use my F-150 4 door 4x4. My Ranger will do it, but not the safest option I have.
Fleener
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