4140 vs. Stainless Steel


PDA






GConn
February 2, 2011, 03:33 PM
Is this (found on the web) True, please?

"Firearms
This steel is used by some firearm manufacturers for revolver frames, barrels, actions and pistol frames. Gun barrels made of 4140 steel wear longer than those made of stainless steel. When oil quenched and tempered, 4140 steel becomes even stronger, about 180,000 psi."

http://www.ehow.com/list_7242476_4140-steel-uses.html

PS ~ Hoping (believing) that I have followed proper conduct/protocol for posting www info -> in other words: NOT "infringed" on a copyright...?

If you enjoyed reading about "4140 vs. Stainless Steel" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!
dfariswheel
February 2, 2011, 07:29 PM
Nope.

Stainless will last longer because it resists the erosion of the throat caused by the super hot burning powder.

Notice that virtually all Match rifle barrels you see on the line are stainless.
This isn't because stainless is more accurate, it's that the barrel retains it accuracy longer than a 4140 steel barrel.

SlamFire1
February 2, 2011, 07:47 PM
This can cause lots of discussion.

The problem is, barrel life is extremely varible.

I remember being squadded with Lee Land, a President 100 winner, and he had a barrel whose throat eroded one gage number per match. That's awful.

I have shot out stainless and chrome moly barrels, and I cannot prove that that one barrel type provides better barrel life or performance than the other. I am of the opinion that chrome moly barrels will last longer than stainless, but I will never be able to prove it in my lifetime.

The heat treated numbers for 4140 are correct, but barrels have to be pretty soft to gun drill them and rifle. Maybe if they were heat treated afterwards we would see something. But then the barrels would probably warp.

You can check out material properties on MatWeb. Metals really improve with heat treatment. But only actions are heat treated.

While you pay a bit more for a stainless blank, you don't have to pay to have the thing blued. That is about $75-$100. Bluing pretty much removes whatever cost advantage chrome moly has. That is why I am buying stainless blanks and the last rifle I had rebarreled with a stainless Krieger. I suppose you could spray paint the barrel. Stainless seems to clean up quicker, but I don't know if it is real.

http://img.photobucket.com/albums/v479/SlamFire/M70%20pics/DSCN0958.jpg

I had lug galling problems with a stainless Winchester M70 Classic action. Because of that, I am not ever buying an all stainless rifle action again. I will stick to chrome moly.

Jesse Heywood
February 3, 2011, 04:24 AM
I just love ambiguous statements. He calls for a known steel alloy heat-treated to spec. And compares it to stainless steel that is of unknown alloy and heat-treatment.

I designed a lot of aircraft parts using stainless steel, and with the proper alloy and heat-treatment it will outlast the 4140 HT 180 KSI due to its fracture toughness ability. The SS will be softer and far more forgiving to damage from the burning powder, heat from the friction of the bullet and abuse in general.

One project I was on involved replacing bolts made from 4140 heat treated to 180+ KSI. The bolts were cracking. My replacements were made from 15-5PH Cres or an Inconel alloy.

SlamFire1
February 3, 2011, 07:22 AM
I designed a lot of aircraft parts using stainless steel, and with the proper alloy and heat-treatment it will outlast the 4140 HT 180 KSI due to its fracture toughness ability. The SS will be softer and far more forgiving to damage from the burning powder, heat from the friction of the bullet and abuse in general.

One project I was on involved replacing bolts made from 4140 heat treated to 180+ KSI. The bolts were cracking. My replacements were made from 15-5PH Cres or an Inconel alloy
Maybe you could tell me why I had galling on my M70? The lugs and receiver seats were “trued”, so if there were any surface treatments they were removed. However, I don’t know if stainless has any equivalent surface treatments like carburizing.

brickeyee
February 3, 2011, 12:47 PM
I had lug galling problems with a stainless Winchester M70 Classic action. Because of that, I am not ever buying an all stainless rifle action again.

Bad choice of metal for the parts.

If they had used different types of stainless for the two parts they likely could have eliminated the problem.

This showed up in early stainless pistols.
When the frame and slide are the exact same metal galling showed up.
A change to slightly different types eliminated the problem.

bobalou
February 3, 2011, 09:40 PM
I would like to know what is the "alloy" used in a Bersa uc 9mm frame and slide and is it "ordnance grade" and is there a specific process to meet the quality/ wear factor that is a "standard" for "ordnance grade", such as "drop forged". I assume most gun barrels are at least hardened steel of high grade. I find a lot of these descriptions of quality to be ambiguous to say the least.:confused: Taurus pt99 claims they have drop forged frames of ordnance grade alloy. WOW. What kind of alloy? Is there drop forged, ordnance grade pot metal? What are the requirements of "ordnance grade"?

dfariswheel
February 3, 2011, 09:53 PM
"Ordnance Grade" simply means it's some kind of steel that can be successfully used to build guns, or part of.
In truth, it's an advertising ploy to make you think it's some kind of super metal. It's just a steel.

As I recall, rifle and revolver barrels are not heat treated. Once the blank is manufactured and rough drilled no other hardening is needed or done. Rifle and revolver barrels are not especially hard and don't need to be.
Automatic barrels that have locking lugs and operating surfaces must be hardened to prevent wear.

Currently a popular advertising gimmick is listing AR-15 barrels as "Chrome Moly steel".
The barrel is made of a type of steel known as a chrome moly, but the intent is to make the unwary buyer think he's getting a chrome LINED barrel when all he's really getting is the same 4140 chrome moly steel that's been used by gun makers since at least the 1930's.

The truth about "Ordnance Grade Steel" is that gun makers use the softest, cheapest steel they can THAT WILL DO THE JOB.
Harder steel and higher grade steels just eat up milling and lathe bits, drills, and broaches, so gun makers use as little of that as they can to save the tooling.
There's the story that when S&W made the first stainless steel Model 60 revolvers they weren't sure what exactly was needed, so they used a higher grade tool quality stainless steel. It just devoured their tooling so they changed to a lower grade, softer steel.

blackguns
February 4, 2011, 12:07 PM
Most stainless really isn't all that hard in the grand scheme of hard metals. But many alloys are very tough and create a lot of heat when cutting, drilling etc. Even premium carbide tooling coated in the latest and greatest "unobtanium" coatings can only work so long and so fast in stainless.

A slightly alloyed carbon steel like a 4140 even pre-hard stuff to 34Rc cuts like butter compared to a good stainless.

There are a million alloys out there and I'm sure if you started with plain carbon steel (1018)and began adding alloying elements to improve things like wear and notch resistance, strength, corrosion resistance, etc, you would end up with something both impractical to machine and too expensive to justify.

Everything is a compromise. A Chrome lined, Cro-moly barrel is probably the best balance of all things but as someone said you probably won't notice a drastic difference in a lifetime.

brickeyee
February 5, 2011, 09:53 AM
But many alloys are very tough and create a lot of heat when cutting, drilling etc

Stainless tends to be 'gummy' and not make nice chips (and chips play a big part in removing heat from cutting).

The addition of sulfur forms small inclusions to promote chip breakage while not reducing strength excessively if the metal is heat treated and rolled correctly.

The goal is small but uniform sulfur inclusion, not large inclusions that would create weak spots and promote fracturing in use..

blackguns
February 5, 2011, 12:18 PM
Yeah that is the major difference between 304 which is a non chip forming PITA to machine and 303 which has inclusions that allow short chipping.

Most critical applications will avoid the use of 303 because the quality control and consistency of the process can allow for unpredictable fracture properties.

brickeyee
February 5, 2011, 12:37 PM
Didn't TYIKA has a bad batch of barrels a while ago from incorrect heat treat to diffuse the sulfur?

Not all heat treat is for hardness.

Big Az Al
February 10, 2011, 09:36 AM
My Favorite gun guru, who made and built barrels and rifles, tested, tested to destruction and then sliced diced and analyzed the results.

Made the claim "that Stainless barrel's are over rated because to use a grade that would do what was being claimed could only be done with a grade that would result in ten times or more the cost of tooling used in barrel making or then any carbon steel did or does."

I am sure there are grades of steel and stainless steel that would be very good barrels, maybe even better then carbon steel alloy's if the cost of machining the barrel is not cost prohibitive.

But I have not seen any several thousend dollar wonder SS barrels being touted! That have proved out to be any better then a standard carbon moly alloy steel!

So IS there is a chance he is still right, 50 years later?

Me? I do believe he is and has been right all along!

dfariswheel
February 10, 2011, 07:20 PM
There's a huge difference between the stainless alloys that were available 50 years ago, and even more difference in the knowledge of how to build a stainless barrel.
50 years ago stainless barrels were almost unheard of, and were hard to come by. Quality was suspect.

All we can do is go by the real experts, the bench rest and Match shooters who buy the best custom barrels money can buy, then shoot them until the accuracy starts to degrade.

On the bench rest and match ranges you see just about nothing but stainless barrels.
If carbon steel were as good as, and lasted as long as stainless, these people would have figured that out and you'd be seeing carbon steel barrels on the line.
You don't.

Shooters at this level don't buy into stories or interesting theories. They go by actual results proven over years and thousands of shots.
A good carbon steel barrel will shoot as good as a stainless, but it won't maintain that accuracy as long as stainless.

If you enjoyed reading about "4140 vs. Stainless Steel" here in TheHighRoad.org archive, you'll LOVE our community. Come join TheHighRoad.org today for the full version!