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Difference between MIL-C-5541E, AMSC5541, and MIL-DTL-541F?

Q. What is the difference between MIL spec MIL-C-5541 and MIL-C-5541E?

Ken Daly
- Greenville, South Carolina

A. Just the revision level, Ken. Rev. D was released in 1989. Rev. E came sometime after that, probably the mid 1990's. These days people should specify MIL-DTL-5541 [on DLA]

There have been long debates here regarding whether you should process parts on old non-revised drawings per the original spec or the latest revision but I'm not aware of any guidance on this from the spec-writing bodies.

Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

Q. Our company was currently audited by NADCAP Auditors. One of their write-ups was that we were using the MIL-C-5541 E where it was superceded by AMSC5541. I find no reference that this has actually happened. Could you please give your advice?

Janiece DeLaGarza
- Wichita, Kansas, USA

simultaneous replies

A. There are two sides to the story as I read it. First, the Department of Defense still considers the Mil-C-5541E an active document for aluminum chromating. The way you stated your write-up, the auditor questioned your using the Mil spec and qualifying to AMS, or where the process specified the AMS spec. The AMS spec is currently used by several aerospace manufacturers, and as such, you would be required to conform to the requirements of that spec.

Best of Luck,

Ira Donovan, M.S.F.
Kansas City, Missouri

A. Janiece, if the NADCAP folks insist on playing specsmanship games, they should know that Mil-C-5541E is a correct, current, and active document for chemical conversion coating on aluminum and aluminum alloys. The SAE jumped the gun and published AMSC5541 before the DoD (specifically, the Naval Air Systems Command) cancelled the Mil-C-5541 document, and the AS group has shown no intention of canceling Mil-C-5541. Someday, Committee B of the Aerospace Metals Division of the Society of Automotive Engineers will get around to canceling AMSC5541, but that hasn't been brought up in any agendas I can recall. The ASSIST website at should get you to the latest revision.

What's odd is that NADCAP knows about this, but such knowledge probably conflicts with Rule 1: NADCAP checklists are always right. (Hope you don't mind my doing a bit of grousing about NADCAP!)

If you can get past NADCAP egos, you might be able to point out that AMSC5541 is a word-for-word conversion, with only editorial formatting, of Mil-C-5541: and the Notice in the front of AMSC5541 clearly states this. So if you're working to Mil-C-5541, all the requirements are there.

Good luck!

lee gearhart
Lee Gearhart
metallurgist - E. Aurora, New York

What AMS spec is equivalent to MIL-C-5541 Type 1 Grade C, Class 3

Q. I have an old print calling out this chemical film - which AMSC5541 spec would be the equivalent 1A or 3?

Billie Buchanan
buyer - Wichita, Kansas

A. It's been a confusing few years as it seems that the feds were trying to move specs from the Mil system to AMS standards, Billie. So new standards were written but old ones are not cancelled, etc.

Because of that, I think you are not asking quite the right question. I think the right "update" for MIL-C-5541 would actually be MIL-DTL-5541 [on DLA] F. In that case, Class 3, is for "protection against corrosion where low electrical resistance is required" and you would spec Type I for "Compositions containing hexavalent chromium" or Type 2 for "Compositions containing no hexavalent chromium" (which would be the new TCP formulations). I don't know what "Grade C" means -- sorry. Good luck and get back to us if I have misunderstood the situation.

Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey

Q. I need to determine the difference between a reference to MIL-C-5541 E and MIL-DTL-5541 [on DLA]F as the certification that I receive with material contains a reference to MIL-C-5541 E. That certification recently changed to MIL-DTL-5541 F. Can anyone shed light on this?

Debbie Kidder
regulatory affairs - Minnetonka, Minnesota, USA
March 18, 2008

A. The actual change, I believe, is that TCP (trivalent chromate product) is now permitted under MIL-DTL-5541 [on DLA]F.

Why the "style" of the spec went from "C" to "DTL", I don't know and I'm not in the loop. I hope that someone can help us out. But my interim understanding is that DTL is an abbreviation for 'detail' and it is used when a spec requires that certain "process details" be adhered to, as opposed to just being a "performance" spec.

Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
March 28, 2008

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A. Hey, at least they upped the revision letter!

I agree, Ted -- the biggest difference between MIL-C-5541E and MIL-DTL-5541F is that the buyer can ask for a "Type II" coating which will contain no hexavalent chromium. Currently, only the trivalent chromate formulation developed by NAVAIR is listed in the MIL-DTL-81706 [on DLA] spec, which governs the materials one can use for a proper MIL-DTL-5541 coating.

We consider a cert with "MIL-DTL-5541F" to be acceptable for parts requiring chemical conversion coating per MIL-C-5541.

The "DTL" is indeed short for "detail", and was done to reflect the move away from 'how-to' type specifications, to one that merely lists the important details of the requirements. I have to say I'm not certain of the difference between a 'detail' specification and a 'performance' specification such as MIL-PRF-46010 [from DLA] , which lists the performance criteria the coating is supposed to withstand.

By the way, the letter in the Mil and Fed specs is merely the first letter in the title of the specification. So here "C" is for "Chemical", and in QQ-P-35C (canceled) [link is to free spec at Defense Logistics Agency,], the "P" was for "Passivation".

It doesn't have to make sense.

lee gearhart
Lee Gearhart
metallurgist - E. Aurora, New York
April 8, 2008

Q. We use AL 6061-T6 parts finished with Chromate Conversion Coating per MIL-C-5441 Class 3.
Is this coating RoHS compliant? I was not able to find MIL-C-5441 spec on the net, is it still active?

Alex Sidorovsky
Component Engineer - San Jose, California
April 28, 2011

A. Mr. Sidorovsky, I hope you've got the answer to your question by now but my two cents after poring over the specs for a couple hours:

If the drawing doesn't specify Type II (non-hexavalent chromium), then it shouldn't be RoHS compliant. 5541 says to default to hex chrome material (Type I) if a material type isn't specified in the contract. For a copy of 5541 (it's now MIL-DTL-5541) and other mil specs, go to  or

Jason Mansfield
- Milwaukee, Wisconsin, USA
January 10, 2012

Ed. note, April 2014: the URL for the 'assist' site is presently

Q. This looks like a good place to post the related question:

What are the differences between MIL-DTL-5541 and '81706?

The only thing I can discern is the performance of the coating; 5541 test samples are allowed corrosion after testing and 81706 samples aren't? All the chemicals used are identical.

Thanks for your comments!

Jason Mansfield [returning]
- Milwaukee, Wisconsin, USA
January 10, 2012

A. Through conversations with others, I was able to grasp the difference between MIL-DTL-81706 and MIL-DTL-5541 and wanted to post for anyone else who may have questions about it:

81706 is the spec to which the conversion coatings themselves are qualified. Suppliers develop materials and processes that are approved for use after much testing. This is the "theoretical standard" to be met under ideal conditions.

5541 is the spec against which the manufacturer measures their coating _process_ to ensure that the process is being performed properly. Allowance is made for manufacturing tolerances and consumption of the chemical after processing several lots, hence an allowance for slight corrosion. This is the "practical standard" to be met under real life conditions of manufacturing.

Jason Mansfield [returning]
- Milwaukee, Wisconsin, USA
January 12, 2012

Chromating Specifications

Q. What is the difference between MIL-C-5541F and MIL-DTL-81706B. My customer is asking for parts to certified to both specifications, I have never run into MIL-C-81706B.

R Webb
Quality Assurance - Bloomingdale, Illinois USA
April 30, 2014

A. Hi R. We appended your question to a thread which hopefully answers it for you. Supplier companies like Henkel, Macdermid, Chemetall, etc., get their products qualified to be listed in MIL-DTL-81706 (used to be QPL-81706 for 'Qualified Products List'), then you as the applicator follow the instructions in MIL-DTL-5541, but you must use one of the products listed in MIL-DTL-81706 when doing so.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
April 2014

thumbs up sign Thanks for your help and linking my question to a previous thread. Nothing like a conversation that spans a few years!

R. Webb [returning]
- Bloomingdale, Illinois USA
May 1, 2014

Q. Hi, I found that, in some drawing, the finish for aluminum plate is MIL-C-5541, and some is MIL-DTL-5541, So what is the difference between MIL-C-5541 and MIL-DTL-5541?


Liu Guoxia
- Beijing,Beijing,China
December 2, 2015

A. Hi Lydia. As you can now see from the earlier postings on this thread, MIL-DTL-5541 is the current standard, and Mil-C-5541 is the older standard. You should probably ask your Mil-C-5541 customer to update their requirements to the current specification. Good luck.


Ted Mooney,
Ted Mooney, P.E.
Striving to live Aloha - Pine Beach, New Jersey
December 2015

A. On the DLA Assist Quicksearch page, MIL-C-5541 revision E is found on the same page as MIL-DTL-5541 revision F. At some point a great many standards got changed over to the DTL designation (according to Wikipedia it means "Detail Specification", no idea what the "C" used to refer to*) but it seems to be a distinction without a difference.

Though obviously everybody should be looking at revision F rather than the older copies.

ray kremer
Ray Kremer
Stellar Solutions, Inc.
supporting advertiser
McHenry, Illinois
stellar solutions banner
December 4, 2015

Ed. note: * Lee Gearhart advised an earlier writer that "C" stood for "Chemical".

Q. I need help concerning AMSC5541 and MIL-DTL-5541. The AMS Standard on the SAE website states 'cancelled' with no direct note of MIL-DTL-5541 superseding. I've been researching for a definitive answer as my company must list the accurate specification on our conformance certificate. Should we be listing MIL-DTL-5541 since AMSC5541 has been canceled?

Joseph Sanchez
Conductive Gaskets - San Fernando, California, USA
April 20, 2017

Probably the answer you are looking for is from Lee Gearhart up near the top of the page from 2002.

ray kremer
Ray Kremer
Stellar Solutions, Inc.
supporting advertiser
McHenry, Illinois
stellar solutions banner
April 28, 2017

Q. Is there a technical concern if my part were to have been initially chemical conversion coated with type 1 material and then touched-up in small areas with type II material where there was mechanical damage to the part that required metal to be removed to flatten out a dent and remove a burr?

B Brimhall
- Salt Lake City, Utah, USA
May 14, 2018

A. Hi B. Although it might be unlikely that there would be any reaction between the two materials, who would want to be on the hook to have to prove it if anywhere down the line the component had trouble of any sort, related or unrelated? I wouldn't do it; I'd get some material made for touching up Type II.


pic of Ted Mooney
Ted Mooney, P.E. RET
Striving to live Aloha - Pine Beach, New Jersey
May 2018

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