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What grades of stainless are used in handguns?

Discussion in 'Handguns: General Discussion' started by Tropical Z, Dec 23, 2003.

  1. Tropical Z

    Tropical Z Well-Known Member

    Numbers wise?
    Are the same grades used for the slide as well as the frame?

    PCRCCW Well-Known Member

    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.
  3. mete

    mete Well-Known Member

    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.
  4. Tropical Z

    Tropical Z Well-Known Member

    Is there a 4040 stainless?
  5. DBR

    DBR Well-Known Member

    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.
  6. mete

    mete Well-Known Member

    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.
  7. wintermute76

    wintermute76 Well-Known Member

    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 Well-Known Member

    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.
  9. Jeff OTMG

    Jeff OTMG Well-Known Member

    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.
  10. mete

    mete Well-Known Member

    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.
  11. c_yeager

    c_yeager Well-Known Member

    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.
  12. scalinghammer

    scalinghammer Member

    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.
  13. zpo

    zpo Well-Known Member

    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.
  14. PCRCCW

    PCRCCW Well-Known Member

    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.................
    Last edited: Dec 26, 2003
  15. JiminCA

    JiminCA Well-Known Member

    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.
  16. JiminCA

    JiminCA Well-Known Member

    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.
  17. harrydog

    harrydog Well-Known Member

    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.
  18. Owen

    Owen Moderator Emeritus

    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.

  19. John Forsyth

    John Forsyth Well-Known Member

    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.
  20. harrydog

    harrydog Well-Known Member

    "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.

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