Mil specs for metal and what they really mean??

grinch · Apr 6, 2007

I got some drawings that specify material with a bunch of mil spec crap and I cant find what it translates into in the real world.

QQ-S-763:class 420

I mean what the hell does this really mean??

Thanks
DA Grinch

superalloy · Apr 6, 2007

Try a google search. It yielded an answer in about 2 nanoseconds.

Maybe you are not qualified to do the work, if you don't know the spec and can't figure out how to find it???

grinch · Apr 6, 2007

oh oh oh please say it aint so oh great one

Yes if you found the right one smart ass them post it. Funny several engineers didnt come up with it today.

nanosecounds LOL ass clown

acutron · Apr 6, 2007

http://en.wikipedia.org/wiki/Defense_Standard

Jared M · Apr 6, 2007

QQ-S-763 is stainless steel bar, in this case 420 stainless. Wasn't difficult to find.

Slipup · Apr 6, 2007

QQ-S-763 deals with corrision resistant steel bars, wire, shapes and forgings. Class 420 is the hardness required, and is the class needed for use in ball and roller bearings, cutlery and other parts requiring high hardness.
Like Jared said. 420 Stainless.

grinch · Apr 6, 2007

Cool thanks guys.

I'm not an engineer or a machinist as you can tell I just do design concept work and have some engineers I consult with to get stuff done. I come here on a regular basis for the helpful folks so thank you guys again. This I'm sure is easy to you cuz you work with it as I'm sure I can goto my day job and find alot of things others wont understand with out it being explained.

Neil · Apr 6, 2007

I have a hard copy of this document-its about as big as 4 or 5 large sized Machinery's handbook. It is a really neat book, check it out. It's commonly called Military Handbook 5.

Mil Hndbk 5

acutron · Apr 6, 2007

This should help also

AISI Type 420

Category Steel
Class Stainless steel
Type Martensitic standard
Common Names Chromium steel
Designations France: AFNOR Z 20 C 13
Germany: DIN 1.4021
Italy: UNI X 2O Cr13
Japan: JIS SUS 420 J1
Sweden: SS 2303
United Kingdom: B.S. 420 S 37 , B.S. CDS-18
United States: AMS 5506 , AMS 5621 , ASTM A276 , ASTM A314 , ASTM A473 , ASTM A580 , FED QQ-S-763 , FED QQ-S-766 , FED QQ-W-423 , MIL SPEC MIL-S-862 , SAE 51420 , SAE J405 (51420) , UNS S42000

Composition

Element Weight %
C 0.15 (min)
Mn 1.00
Si 1.00
Cr 12.0-14.0
P 0.04
S 0.03

Mechanical Properties

Properties Conditions
T (°C) Treatment
Density (×1000 kg/m3) 7.8 25
Poisson's Ratio 0.27-0.30 25
Elastic Modulus (GPa) 200 25
Tensile Strength (Mpa) 860 25 annealed, cold finished (wire) more
Yield Strength (Mpa)
Elongation (%)
Reduction in Area (%)
Hardness (HRC) 52 25 tempered at 205°C (bar)

Thermal Properties

Properties Conditions
T (°C) Treatment
Thermal Expansion (10-6/ºC) 10.3 0-100 more
Thermal Conductivity (W/m-K) 24.9 100
Specific Heat (J/kg-K) 460 0-100

Electric Properties

Properties Conditions
T (°C) Treatment
Electric Resistivity (10-9W-m) 550 25

superalloy · Apr 6, 2007

The several engineers are idiots too, if they couldn't find it. Why should others do your work for you. Lazy!

kochevnik · Apr 6, 2007

These guys sell it. I'm sure lots of others do too.

http://www.primemetals.co.uk/pmstainlesssteel.htm

grinch · Apr 6, 2007

superalloy,

LOL well very very sucessful idiots then

I find it comical you feel the need to post in this thread just to act like a jackass.

bet you got picked on as a kid and over the internet is the only way you can act like a hard guy where you know you are safe from getting your teath knocked out.

thank you to the others now I see what your talking about.

LOL

RAS · Apr 6, 2007

Superalloy,

As a wise man once said:
"It is better to be silent and thought a fool than to open one's mouth and remove all doubt."

RAS

acutron · Apr 6, 2007

Grinch,

I used to qc for a company that made nuclear sub components. Make sure when you get the mil-spec certs from your supplier that every single number & letter is clearly legible, especially from a fax. If any characters in the document are not clear & could be mis-interpreted, major headaches could come with the job. I had to go through an unpleasant internal audit because of this. A 5 on a fax looked like a 6 & the 6 fell outside a specific range & caused holy hell. I did not catch this & sent the certs to the U.S. Dept. of Nuclear Fuels & quickly found out that they really do pay people to sit & read these documents.

FranH · Apr 6, 2007

Every place has their idiots.

I knew of a machinist with over 30 years experience who never met a 1-2-3 block. (He worked in a turning dept.) An areospace job shop nearby hired a moldmaker with 20 years experience as toolmakers are in short supply. He didn't know what a counterbore is. The owner of that same company reamed out a foreman that requested some India stones. He thought the request was for jewelry. He also doesn't know what a die shoe is. (This within the past 2 months.)
Doing defense work requires exotic and sometimes obsolete material. To find suppliers and specs for substitute material can take DAYS. Some place sell the info....but is it complete and correct and do you know this before hand?

Mil Hndbk 5 is going to be printed........ALL 1,000,000,000,000,000,000 pages. NEVER knew it existed.

Just because we may be an expert in our little niche does not require everyone else to be the same.

While discussing RFID (Radio frequency identification tags), our QAR (Quality Assurance representative) from DOD stated.... "The government is using this program to verify the information....but it is not a gov't approved program...so you need to find a way around it with a gov't approved program before it can be accepted.".....Does this define oxymoron?

We deal with 'challanged people' daily in life....I guess it's just part of life. I try not to flame unless someone wishes to harm themselves or someone else thru ignorance or stupidity.

So thanks Neil a thousand times over for the handbook info......now to print it.

Dimitri · Apr 6, 2007

Neil,

Thanks for the link to the handbook.

Dimitri

superalloy · Apr 6, 2007

grinch:

You start your post with a dismissive tone:

mil spec crap

I mean what the hell does this really mean??

You want to do defense work (MY tax money, MY countrymen, soldiers) at risk, you damn well better take it seriously.

Milspecs exist for a reason: there's a long history of defense contractors cheating the government and getting people killed, either through dishonesty or incompetence. This goes all the way back to the Civil War, and beyond.

Working to the proper specs isn't just some additional bureacratic hoop to jump through: It assures that our soldiers, sailors, marines and airmen get the proper equipment to defend themselves and our nation.

So yeah, I think it might be worthwhile for you to fully understand what you're getting into and fully understand the expectations before you sally forth into the (to you) unknown.

And as far as the personal insults: right back at ya!

grinch · Apr 6, 2007

See once again you chim in with knowing nothing of what I'm doing just assumptions of what I'm doing.

I'm not doing defense work I'm making something for the civilian market and am only getting the info since what I'm working on will have a similar use.

Since I actually work with military procurment it would be not be a good thing for me to try to sell stuff to the military until I get out.

Oh and as far as "your soldiers" unless you've been there putting your life on the line with substandard gear do not run your suck. I HAVE BEEN and I've had team mate die from it so you have no room to lecture me.

http://www.youtube.com/watch?v=kNHLKFsda-w

All the men in the video link but one are dead and not completely but in part from cheaply made weapons systems.

I KNOW the cost

Yea I dont have an engineering back ground and I dont have the freedom to goto school but I get alot of good help and info from places like this forum.

So once again if you have nothing constructive to add to my thread just past it by then

Grinch

superalloy · Apr 6, 2007

Since I actually work with military procurment

Which makes your tirade all the more laughable.

If you're such an expert in military "procurment" as you put it, why are you coming here for help?

Gary E · Apr 6, 2007

Maybe clerks need help once in a while...
or gofers get lost sometimes and need directions ..

Even the lowliest of buyers of material would recognize the QQ-S-763:class 420 as first a Stainless and even if they didnt, the QQ-S should of jumped out as a steel of some sort and then pointing them to the book to look it up.

Mil specs for metal and what they really mean??

Cast Iron

Cast Iron

Cast Iron

Aluminum

Plastic

Plastic

Cast Iron

Hot Rolled

Aluminum

Cast Iron

Aluminum

Cast Iron

Stainless

Aluminum

Hot Rolled

Titanium

Cast Iron

Cast Iron

Cast Iron

Diamond

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