What specs govern "gun quality steel"?
What specs govern "gun quality steel"?
(OP)
Today I had a customer contact me asking if "regular" 8620 steel would respond to heat treat any differently than "gun quality" 8620 steel. I speculated that "gun quality" steel might have tighter alloy and cleanliness tolerances but for their application (a small part with a shallow case depth) I didn't expect any significant difference.
I would like to follow up after having reviewed the actual (not my speculation) requirements for "gun quality" but wasn't able to find anything from my friend Google - maybe I'm searching for the wrong term?
Any tips on what criteria or specifications mills use when certifying a lot of steel as "gun quality" would be much appreciated. (I'm in the U.S. if that affects the answer.)
I would like to follow up after having reviewed the actual (not my speculation) requirements for "gun quality" but wasn't able to find anything from my friend Google - maybe I'm searching for the wrong term?
Any tips on what criteria or specifications mills use when certifying a lot of steel as "gun quality" would be much appreciated. (I'm in the U.S. if that affects the answer.)





RE: What specs govern "gun quality steel"?
However I know of a number of gun applications that use free machining steels that have very dirty microstructures, and they do this on purpose to design in a failure mechanism.
I means whatever the buyer wants it to mean.
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P.E. Metallurgy, Plymouth Tube
RE: What specs govern "gun quality steel"?
If you want a spec for vacuum melt 8620 bar try AMS 6277. It's "premium aircraft quality" as opposed to "gun quality".
RE: What specs govern "gun quality steel"?
RE: What specs govern "gun quality steel"?
RE: What specs govern "gun quality steel"?
I took a look at the material note on an old (1977) US Army M16 bolt carrier print. The note reads, "STEEL, AISI 8620, BASIC OPEN HEARTH, GUN QUALITY, COLD DRAWN, STRAIN RELIEVED BAR, MAX BRINELL HARDNESS 241, AIM FOR 217/229."
Here is a link to a public source US Army drawing for the M16 gas key. The material called out is, "STEEL, AISI 4130, GUN QUALITY, MAX BHN 229".
Apparently the description "gun quality" steel meant something to the US Army ordnance folks back in the 70's. But the specific definition of "gun quality" steel is probably part of some DoD procurement spec that was cancelled long ago.
RE: What specs govern "gun quality steel"?
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RE: What specs govern "gun quality steel"?
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P.E. Metallurgy, Plymouth Tube
RE: What specs govern "gun quality steel"?
RE: What specs govern "gun quality steel"?
And if my customer doesn't care why should I?
I do try to deliver products that meet customers unstated needs, but at the same time there are people that I don't supply any longer because they were never satisfied and they couldn't explain why.
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P.E. Metallurgy, Plymouth Tube
RE: What specs govern "gun quality steel"?
I passed on to our customer that there is no current industry standard for "gun quality" and that any certifications to that effect are referencing a specific agreement between that mill and that purchaser. It sounds like, as a few of you suggested, their company had some verbal agreement with their usual material supplier but all the people who knew what the agreement was have moved on.
They seemed happy with the information I gave them. Thank you to everyone for helping us both learn something :)
RE: What specs govern "gun quality steel"?
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P.E. Metallurgy, Plymouth Tube
RE: What specs govern "gun quality steel"?
RE: What specs govern "gun quality steel"?
Words to live by! Consulting engineering would be a great gig if it wasn't for the dang clients
RE: What specs govern "gun quality steel"?
RE: What specs govern "gun quality steel"?
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P.E. Metallurgy, Plymouth Tube
RE: What specs govern "gun quality steel"?
As you note, the title of a particular material spec may not mean much on its own. But the detail information within the spec can be very important when it comes to establishing reliability, fatigue life or fracture properties of a critical component made from the material.
RE: What specs govern "gun quality steel"?
RE: What specs govern "gun quality steel"?
http://quicksearch.dla.mil/Transient/1A0B24BDA1304... MIL-S-21156 STEEL BARS, HEAT TREATED (FOR 20MM AND 30MM AIRCRAFT GUN BARRELS (NO S/S DOCUMENT)
It's no longer in force, and there is no superseding document, so it must not be that important now.
TTFN
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RE: What specs govern "gun quality steel"?
RE: What specs govern "gun quality steel"?
We actually supply 416 (free machining) for a gun barrel application. The want material with stringers in it so that they can control the failure mode (barrel before breach).
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P.E. Metallurgy, Plymouth Tube