What grades of stainless are used in handguns?


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Tropical Z
December 23, 2003, 10:01 AM
Numbers wise?
Are the same grades used for the slide as well as the frame?

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PCRCCW
December 23, 2003, 10:22 AM
Typically you'll see alot of various 400 Series used. Anything from 400 - 499 fits this Series.

The hardness will vary from company to company. Its common to have frames hardened less than the slides. 30 Rockwell is an example for frame hardness while a slide can have 40+ for its Rockwell rating.

They do this as the frame takes more "recoil" than the slide and they want more flex in the frame. If it gets hardened to much...it will stress fracture.

Im sure gun companies have tried and use others..but this is "common" practice for most that I know of.

Shoot well.

mete
December 23, 2003, 02:48 PM
416 stainless is common for barrels and other parts .Ruger uses it in their investment cast parts . It's the free machining grade of 410 which is heat treatable.

Tropical Z
December 23, 2003, 10:40 PM
Is there a 4040 stainless?

DBR
December 23, 2003, 11:07 PM
One of the best '"common" grades of cast stainless for strength and corrosion resistance is 17-4. Seecamp used it. I am not sure who else may use it. Maybe NAA.

mete
December 23, 2003, 11:25 PM
There is a 440 stainless steel , comes in three grades depending on carbon content 440 A, B and C. They are commonly used as knife steels.

wintermute76
December 24, 2003, 06:20 AM
typacally steels with a 4 digit number are non stainless, the first 2 digits are the major alloy designation, and the second pair is the carbon 1/10 percentage. e.g. 4140 is a chromium/ molybdenum alloy with .40% carbon content.

stainless are a little different. 400 series are heat treatable for the most part and magnetic. Don't get full corrosion resistance until they are hardened, the harder, the more resistance.

300 series are non magnetic, and generally not heat treatable.

there are other grades, 17-4 was mentioned, 18-8 sounds familiar. not sure how these fit in offhand, would need my machinery's handbook, but then we get into austentic and martensitic, and it's probably a bit overboard ;)

PCRCCW
December 24, 2003, 09:30 AM
Actually 300 series is quite heat treatable..but doesnt have the range of finished hardness's as 400 series does.

400 is softer in its annealed form or unhardened state than 300 series is and has a better machinability factor before hardening.

Shoot well.

Jeff OTMG
December 25, 2003, 01:04 PM
There was something like 14 different stainless steels used in the Detonics Pocket Nine. Back then galling of like stainless steels was a problem so Sirkis used different types to prevent it. AMT used the same steel in the slide and frame, but heat treated them differently to make the steels look different to each other.

mete
December 25, 2003, 02:00 PM
PCRCCW, As a metallurgist I'd like to know how the 300 series can be heat treated other than annealing after work hardening. You must have discovered something that has eluded metallurgists for many decades.

c_yeager
December 26, 2003, 03:38 AM
What i find odd is that Knife people can sit for hours on end debating the various qualities of a half dozen different types of steel. While gun people pretty much arent concerned with it so long as it works. I wonder which group is right.

scalinghammer
December 26, 2003, 08:42 AM
Most of the large volume firearms manufacturers use mostly 410 and 416 for hardened parts. There is very little of the 17-4 and 15-5 being used and very little of the 440.
Ed

zpo
December 26, 2003, 09:08 AM
The performance of knives can be traced directly to the composition of the steel,(or titanium for dive and EOD, liquidmetal for the Iwannahaveacoolknife [thats not a diss] and I'm sure other metals for their unique properties). Other factors are blade angle, choils, tang length, and finish. Firearm performance tend to be more of a quality of manufacturing issue. Fit and finish of moving parts. Metal is more important in the overall equation to knives, and other than stainless or blued, is only a problem in the firearm world when its not strong enough. Of course it could be alot more important and we just don't know it yet.

PCRCCW
December 26, 2003, 09:32 AM
Im no metallurgist and wont claim to be the know all and end all, either.

I do know we HT'd 316 Shafting for certain Chemical Applications. It is done on a regular basis in certain Industrial applications. The same methods are NOT used in some of the required applications as typical Heat Treating though.

Wet Hydrogen Firing is a Heat Treatment that will harden certain grades of 300 SS. Im aware of the Austenitic to Martenestic Resistance" typically found in the 300 series of SS. So other methods are utilized.

Shoot well.................

JiminCA
December 29, 2003, 02:01 AM
Well I'm not a metallurgist but I am a Mechanical Engineer and I still remember a bit about this stuff. Also worked with these steels a bit.

Any steel with 11% or more Chromium is considered a stainlesss steel. The Cr allows the material to form a passive Chromium Oxide barrier CrO2 that protects the surface of the metal

Wet H2 firing is not a process that I'm familiar with - but I'd imagine it involves coating the 300 series stainless with a surface "paint" of some sort and then heat treating it in a Hydrogen atmosphere (no smoking, please! :what: ). This is either done in a Hydrogen retort furnace (an upside down bell that holds H2) or a "humpback" furnace (one designed to hold the hydrogen, which wants to rise).

The H2 is a 'reducing' atmosphere, which strips chromium oxides off of the surface of the stainless (the CrO2 is what keeps it from rusting). I'd imagine that your process results in a surface hardening (similar to case hardening or carburizing or nitriding on regular carbon steels). Whatever is placed on the surface diffuses into the top .005-.030 or so of the material, resulting in surface hardening. This is a good process for a shaft as the ductility is maintained internally so that the material is quite fatigue resistant while creating a surface hardness for the bearing running surfaces, etc.

AFAIK 300 series stainless is strictly a strain hardening material. You can buy it in differing tempers - annealed (soft), 1/4 hard, 1/2 hard, full hard, etc. The hardness is established by cold working the material. You can restore it to full softness by annealing it (heating it up to a temperature that allows all of the structure to stress relieve itself). 300 series SS is austenitic, non-magnetic, and offers superior corrosion resistance in non-acid non chloride environments, but can't be hardened all the way through by heat treating it.

To get back to the original question, 400 series SS is typically used for guns. It is a ferritic stainless (magnetic, and less rust resistant as noted above). Different alloys are chosen depending on what use it has (barrel or slide, for instance), and the method of manufacture (forging, machining, casting, cold forming, etc). Some versions are more machinable, or more forgeable, for instance. Typical alloys such as 410 and 416/416S are used. These can form martensite when heat treated and cooled (quenched) properly. This makes for a part that can be hardened after machining, although there is some risk of deformation from the heat treat process.

Some early slides were made with 17-4PH IIRC. The PH stands for precipitation hardening. It involves a supersaturated alloy solution that is cooled rapidly from annealing temperature. If kept cold the alloy stays mixed and it looks like normal alloyed metal. But heat it up a bit for the right amount of time and little crystals of "precipitant" form (typically a carbide) that induce strain in the grain structure and resultant hardness. 17-4 can get really, really hard and I'm not sure but i don't think anyone uses it anymore. Maybe for a slide but certainly not for a frame. (Now that I'm thinking about it - it seems that Caspian may have offered slides made up of the stuff). The great thing about PH material is that you can machine them soft, and then do the relatively low temp precipitation process to bring the hardness up. As the precipitation is at a pretty low temp, the risk of the part distorting is pretty much eliminated.

Hope this helps. It is pretty much about all I recall.

JiminCA
December 29, 2003, 02:13 AM
Well just went and looked at Caspian www.caspianarms.com

They use 416 for slides and barstock frames, 410 for cast frames. There's one data point. Also, if you look at the ed brown, barsto, and schuemann sites you'll probably be able to see what alloy they use on their barrels.

harrydog
December 29, 2003, 09:26 AM
There are several high end custom rifle makers who use 17-4 stainless for their bolts and actions. Rohrbaugh uses 17-4 for their pistol slides and will begin using it for frames next year.
From everything I've read, 17-4 is a stronger steel than 400 series stainless. The tensile and yield strengths can be at least equal to the best 4140 carbon steel, while 416 and 410 stainless can't match the best 4140 steel in terms of strength.
17-4 is also quite rust resistant, so it's an ideal material for use in guns. The reason it isn't used more often is because it is quite difficult to machine and therefore much more costly.

Owen
December 29, 2003, 10:03 AM
400 hundred series mostly, and some PH SS.

Ive used 410, 420 and 416, 17-4, and an 18-CRS (CRS = Can't Remember Stuff)

416 is falling out of favor for barrel manufacture. I know of at least 3 major companies that will NOT use it. The issue with 416 in a barrel is that it can have thingees called stringers. Stringers are defects in the microstructure of the steel that cause weak spots. A barrel with stringers can cause a barrel to blow up, just like Bugs Bunny stuck his finger in the muzzle. Some foundries guarantee they can make 416 with no stringers, but for a large company, the risk isn't worth it. 416 is fine for slides, frames, and a whole mess of other parts that are not pressure vessels.

When you are looking at steels it is important that you don't get caught up in the ultimate tensile strength of hardness of a steel. Steel Frames and slides are generally radically overbuilt. Truly tough, durable parts are not generally very hard. Hard steels crack, and cracks lead to instantaneous failure.

owen

John Forsyth
December 29, 2003, 01:08 PM
While I am not a metalurgist, I am a professional structural engineer. JiminCA is right on the money.

There are four main groups of stainless steels. Austinetic, 300 series, Martensitic & Ferritic, 400 series, and Precipitation hardened. In a nut shell, 300 series, non-magnetic, most corrosion resistant. 400 series, magnetic, heat treatable. Precipitation hardened, magnetic, heat treatable, very high strength, and expensive.

harrydog
December 29, 2003, 06:11 PM
Quote:
"When you are looking at steels it is important that you don't get caught up in the ultimate tensile strength of hardness of a steel. Steel Frames and slides are generally radically overbuilt. Truly tough, durable parts are not generally very hard. Hard steels crack, and cracks lead to instantaneous failure."


I agree that one should not get caught up in the ultimate tensile strength of the steels used, since most are more than adequate for the intended use. But higher hardness and higher tensile strength are not necessarily linked. They are two different things. Knife blades are a good example. It's usually a trade off between softer, which gives a strong, tough blade and harder which gives great edge holding ability but more brittle. So harder is not necessarily better, as you said. But I'm an advocate of using the best material available for the job. I like things overbuilt.

Archer
December 30, 2003, 05:11 PM
Owen said:

416 is falling out of favor for barrel manufacture. I know of at least 3 major companies that will NOT use it. The issue with 416 in a barrel is that it can have thingees called stringers. Stringers are defects in the microstructure of the steel that cause weak spots. A barrel with stringers can cause a barrel to blow up, just like Bugs Bunny stuck his finger in the muzzle. Some foundries guarantee they can make 416 with no stringers, but for a large company, the risk isn't worth it. 416 is fine for slides, frames, and a whole mess of other parts that are not pressure vessels.

Interesting but puzzling comment. The only place I have ever seen this sort of comment elsewhere was on the Schuemann website...where they indicated the presence of the stringers was actually a blessing in disguise as it promotes overpressure-induced barrel failure while still in lockup.

As for large companies using 416...

Nowlin uses 416 in its barrels, which are acknowledged as being among the finest. Nowlin barrels are used in the FBI CIRG specified Springfield Professional Model, which is one of the better full house combat 1911s available.

Bar-Sto barrels are also 416 stainless. Again, Bar-Sto is acknowledged as one of the finer barrel makers.

Ed Brown says he uses 416 stainless in his barrels. I think most people would acknowledge Brown as a high quality maker.

Wilson stainless barrels are reportedly produced by Storm Lake Machine out of 416 stainless. Same barrel vendor makes the Springfield TRP and Trophy match model barrels.

I have not seen too many cases where any of these items spontaneously blow up...

Owen
December 30, 2003, 09:05 PM
harrydog...I had a typo...that what the point I was trying to make. A lot of people think a harder steel is better, or a higher tensile strength steel is better.

Tensile strength and hardness are not the same, but they go in the same direction. In general, the higher the hardness of a given steel alloy, the higher the yield stress. But that same hardness can cause other problems. A medium hardness part will be relatively forgiving of a stress riser. A high tensile strength/high hardness part may fail where a lower hardness part of the same alloy will do just fine, because the softer part (with a lower yield strength) deformed just enough to alleviate the problem.

Also, hard parts have poorer (more poor?) fatigue life. (At least on one of the SS MIM alloys I use at work)

As far as a knife goes the equation is a bit simpler because the blade is thick in the direction of the cutting force, and there are few stress risers in the thin direction. The primary objective is having a steel that is fairly flexible, but will hold an edge. AFAIK, nobody expects a knife to get hammered 10,000 times and survive.

Archer, AFAIK none of those barrel companies are very large. They make maybe 100 barrels a day. The company I work for makes at least 500 barrels a day. The corporation as a whole probably makes 5000 (Five Thousand) Barrels a day. We are not allowed to use 416, because we have been sued numerous times over the 416 issue. I have been told that on some of those guns the barrel looked like a bananna peel, with one of the petals nearly touching the receiver. I know people at other large companies, and they have similar things to say.

The number one reason to use 416 is because it is easy to machine, and easy to cut broach. We don't cut broach (at least at FNMI) so the machinability isn't as big a factor.

As far as Schuemann goes, they can get away with it in a pistol, because the barrel is shrouded by the slide. Those barrel chunks flying about are contained. What if it is the cylinder of your revolver that lets go, or the barrel on your .300 Win Mag?

I'm curious to hear from RemingtonEmployee if BigGreen uses 416.

owen

harrydog
December 30, 2003, 09:29 PM
Archer, you're right. I was thinking about this and was going to make an almost identical post as yours but you beat me to it.
I too remember reading those comments on the Schuemann website, but I've seen no indication anywhere that 416 is falling out of favor for barrel manufacture. It's still used in many high powered rifle barrels as well, and they see pressures much, much higher than any pistol barrel.

This is from the Remington website:



Resistance to the elements is built into this all-weather package of a 416 stainless-steel barreled action set in a strong, stable synthetic stock. Our Model 700™ BDL™ SS is a world traveler, ready for any conditions in any climate. It also brings you the sleek silhouette of a classic stock profile, with hinged magazine floorplate and sling swivel studs.

MODEL 700™ BDL™ SS
Caliber
Barrel Length Rate of Twist Overall Length Avg. Wt. (lbs.) Order No. MSRP*
270 Win. 24" 10" 44 1/2" 7 3/8 29709 $735
7mm Rem Mag. 24" 9 1/4" 44 1/2" 7 1/2 29692 $761
7mm Rem SA Ultra Mag 24" 9 1/4" 43 5/8" 7 1/4 26434 $775
7mm Rem Ultra Mag 26" 9 1/4" 46 1/2" 7 1/2 26275 $775
30-06 Sprg 24" 10" 44 1/2" 7 3/8 29717 $735
300 Win Mag 24" 10" 44 1/2" 7 1/2 29694 $761
300 Rem SA Ultra Mag 24" 10" 43 5/8" 7 1/4 26436 $775
300 Rem Ultra Mag 26" 10" 46 1/2" 7 1/2 26099 $775
338 Rem Ultra Mag 26" 10" 46 1/2" 7 1/2 26101 $775

Owen
December 30, 2003, 10:13 PM
I didn't say no one used it. I said it was falling out of favor.

There is a grade, 416R, that the foundries claim is free from stringers. Maybe it is. Maybe it isn't. Why risk it when there are other alloys that do the job?

Also, reading the copy you posted, is it the action or the barrel that is 416?

owen

zpo
December 31, 2003, 04:57 AM
owen-
nobody expects a knife to get hammered 10,000 times and survive

You don't spend any time on knife boards frequented by Busse and Strider lovers, do you?:D

harrydog
December 31, 2003, 09:00 AM
Quote:
"Also, reading the copy you posted, is it the action or the barrel that is 416?"


Both! And I'll venture a guess that most of the other major rifle manufacturers are using 416 for their stainless barrels as well. Who are the 3 major companies that refuse to use it?

Archer
December 31, 2003, 02:07 PM
As far as Schuemann goes, they can get away with it in a pistol, because the barrel is shrouded by the slide. Those barrel chunks flying about are contained. What if it is the cylinder of your revolver that lets go, or the barrel on your .300 Win Mag?

Well, since last time I checked, this was the HANDGUN discussion forum, so the .300 Winmag was not a subject of discussion.

I agree that the makers I cited are not making 5000 barrels/day, but I suspect a lot more rounds come out of Nowlin, Bar-Sto, and Wilson tubes on an annual, per-unit basis than something from Ruger or other mass makers, because gun gamers tend to use those tubes pretty hard.

Owen
January 1, 2004, 12:57 PM
The companies I know of are Winchester, Browning, FNMI, and Smith & Wesson.

owen

FireInTheHole
January 1, 2004, 01:46 PM
*cough*
Does anybody know what grade of stainless Beretta uses for the 92FS INOX barrels?

I've run some pretty hot stuff through that gun.... failure of an exposed barrel might just ruin my day...

labgrade
January 3, 2004, 01:09 AM
DBR,

"One of the best '"common" grades of cast stainless for strength and corrosion resistance is 17-4. Seecamp used it."

We used this same alloy (w/slight blend) in a MIM-shot for PC drive VCM (head motor) for its high strength & magnetic properties.

Essentially a wax-based/stainless powder-filled, injection molded slurry.

MIM-stuff can be shot at a very high tolerance with zip for machining - unless a lapped surface is desired & that can be had a a pretty goodly rate with decent fixturing EDM.

Too & BTW, many of the "stainless steels" will rust like a bandit.

"stainless" is as much a lie as is "conservative." ;)

harrydog
January 5, 2004, 11:06 AM
Quote:
"The companies I know of are Winchester, Browning, FNMI, and Smith & Wesson."


Any idea what stainless they're using in place of 416?

Owen
January 5, 2004, 09:32 PM
410

harrydog
January 6, 2004, 08:33 AM
I wouldn't have thought 410 was a great choice for barrels, especially high powered rifle barrels. Ruger switched from 410 when they came out with the Super RedHawk.
_______________________________________________________________________________________________________________________



Gunmaker zeroes in on aerospace alloys to toughen its latest product

By Joseph Ogando, Materials and Fastening Editor
Design News
October 16, 2000


Newport, NH —Anyone who decides to shoot a bear with a handgun has two overwhelming concerns. Not missing is really, really important. And so is having a gun with some stopping power since angry bears are unlikely to be gracious about a flesh wound.

The Super Redhawk .454 from Sturm Ruger has nothing if not stopping power. One of the most powerful six-shooters in the world, this revolver shoots a .454 Casull cartridge that packs about 50% more power than a 44 magnum. It's a cartridge that straddles a fine line between bullet and bomb. For the shooter, all this extra muscle translates to a gun that, in the right hands, can drop a bear, elk or other large animal at a distance up to 200 yards. For the engineers who worked on the Super Redhawk, the added power forced them to expand their arsenal of gun steels.

Ruger Chief Engineer Steven Perniciaro points out that the .454 Casull goes off with the highest chamber pressures (62,000 psi) of any handgun on the market. Those pressures—and the resulting stresses—triggered a tightening of strength and fracture-toughness requirements that ruled out the 410 stainless that Ruger successfully uses for smaller guns. "Type 410 stainless just wasn't as strong as we would have liked," Perniciaro says.

Looking for a material that could stand up to the .454, Ruger's engineers decided to give specialty alloys a shot. They constructed the Super Redhawk's cylinder and barrel from alloys that Carpenter Technology Corp. (Reading, PA) first developed for aerospace applications.

Six-shot cylinder. The Super Redhawk's pressure-driven strength requirements are most apparent in its cylinder, which is based on a Ruger 44 magnum. "We decided to scale up and 'ruggedize' our 44 platform rather than reinvent the wheel," Perniciaro says. The scale-up lets shooters move up to a larger caliber with only minimal gain in gun size and weight, and it sets the six-shot Super Red Hawk apart from every other gun in its class. "All the other .454's on the market only have five shots," Perniciaro says. But expanding an existing 44 magnum cylinder also presented a design challenge that intensified the strength requirements for the gun steel. Because the new cylinder has the same OD and bolt center of its 44 magnum forerunner, the wall sections between chambers thinned in proportion to the increase in caliber—or about 25%. As Perniciaro sums up, "The cylinder material had to withstand higher pressures with thinner walls."

Making matters worse, industry practice requires that new gun designs be tested with "proof loads" that generate more than 140% of the chamber pressure experienced in real-world firing conditions. According to Perniciaro, this safety factor means that the Super Redhawk's cylinder actually needed to withstand pressures up to 93,500 psi—greater than the 65,000 psi the gun will see in service and dramatically higher than the 36,000 psi typical with a 44 magnum.

Proof-load tests on a prototype Super Redhawk made from 410 stainless revealed that its first choice would get the cylinder into the safety zone. "410 was strong enough for actual firing conditions but not for the tests," Perniciaro reports. So Ruger produced a cylinder from Carpenter's Custom 465, a martensitic alloy with an ultimate tensile strength of 260 ksi at peak aging. "It passed the tests with no problems," he says, adding that the gun has been out in the field for about a year with no problems.

Looking down the barrel. The 454's extra power also translated to new requirements not just for added strength in the barrel but also for wear and corrosion resistance. Perniciaro explains that impact force and high-velocity gases tend to erode the barrel at the bullet's entry point. This "throat slamming effect" intensifies with cartridge size and velocity.

Doubly concerned about strength and throat slamming, Ruger engineers quickly ruled out 410 stainless steel despite its strong track record on Ruger's smaller revolvers. "After thousands of rounds, we thought we'd see some throat erosion with the 410," Perniciaro notes. The designers next considered conventional 15Cr-5Ni stainless steel (15-5), which met all the design requirements but one. "It was a bear to machine," says Perniciaro. Gun drilling a 0.480 in. diam. hole in a 1.25 inch OD, 19-in.-long bar took 28 minutes in 15-5—a huge productivity tradeoff compared to the 17.27 minutes it takes to machine a comparable barrel from 410. Ruger ultimately met its design and productivity goals with Project 7000, a 15Cr-5N stainless designed specifically for machinability. "Project 7000 let us match the cycle time of 410," Perniciaro says.

Based on this first use of aerospace alloys, Perniciaro predicts a growing role for a host of non-traditional metals whose strength-to-weight ratios will let Ruger's engineers do an even better job at balancing the power, size, and heft of smaller firearms. "New materials will help us to push the limits of handgun design," he says.



Dueling guns

Super Redhawk 454
44 Magnum

Muzzle energy
1,431 ft-lb
933 ft-lb

Muzzle velocity
1,448 ft/sec
1,175 ft/sec

Chamber pressure (proof load)
93,500 psi
57,500 psi

Chamber wall thickness
0.065 inches
0.087 inches

Weight
53 oz
58 oz

Material
Custom 465
410 Stainless

Tensile strength
260 ksi
193 ksi

Yield strength
238 ksi
158 ksi

Density
0.283 lbs/in³
0.280 lbs/in³

wintermute76
January 7, 2004, 03:40 AM
"stainless" is as much a lie as is "conservative."

not really a lie, just what it says "stains less"

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