Copper Contents in ASTM A 213 TP 304L

Your supplier may not be fully informed. How acceptable it may be is up to you and your customer, not your supplier.

Anhydrous ammonia corrodes alloys which contain copper or zinc.

Redox property of liquid ammonia: Cu²⁺ + 2e⁻ ↔ Cu

Stainless steel grade TP304L does NOT contain ANY copper if made to ASTM A213 standards. I would suggest finding a more reputable manufacturer or sales rep. Rather than trying to prove that copper content is OK even though the engineer has specified that the material shall not have any trace, I would suggest spending the money to buy the specified material.

The easiest way to think about this is... what is the pipe company's concern? $$$

The engineer's concern? SAFETY

As per ASTM and ASME SA 213 TP304L, and from Table 2 "Chemical Requirements of Austenitic Steel", there must be no traces of copper in that material as seen from the attached table. So, if there is any traces of copper in the procured material, it shall be rejected as per both codes ASTM and ASME.

.....................

Abdel, are there no notes/footnotes to that table? My ASTM specs are at work...and due to some work being done I canot get in over the weekend...

I believe that 0.78 is high for a residual element, but lack a mental footnote for stainless and no ASTM stainless books here at home...

Milo

Dear Milo

Find the footnotes to Table-2 of SA 213 here Material_SA 213-2007.

Dear Mr Abdel Halim Galala.

Will you please give your expert opinion in the matte.

Regards

ASTM 304L is silent about copper and thus legally the copper content is acceptable. When the copper is limited (as per standard) the comment should be xxxx(max) or traces

But here since your designer has specified the value hence that will over ride the relaxations provided by the standard.

The exact definition of how much is trace as percentage is a bit ambiguous. It obviously does not have a minimum limit. The trace is taken at which one knows that it is present but is so small that it is not measurable. Usually it is in fractions of ppm level or at the maximum in the first digit of ppm.

The listed specification does not say anything about copper content. If you need zero or very low copper content you used the wrong specification.

Dear guest,

Did you get any solution for your problem? We had also experienced such problems of Cu contents and its adverse effects as come forward after installation of tubes. I would like to hear from your side to share the views regarding it.

Regards

Hello zagham. Welcome to CR4.

The outcome is pretty much that Cu is not a listed content metal by ASTM A 213 TP304L (the specification of the OP order). The issue of ASTM A 213 TP304L not noting allowable trace amount is sort of unresolved. The original poster (OP) has ammomia service, which reacts with copper. The vendor providing the tube was trying to sell OP the incorrect material, I believe (incomplete specification notwithstanding).

What is your material inside pipe? Pressure, temperature... anything else you can add may be helpful.

As Abdel Ahlim Galela has pointed out, and as was mentioned by another, the ASTM spec A 213 is silent about copper. Table two last row "others" shows no callout for copper for TP 304 L; The footnotes say nothing about copper. I found no specification basis for rejection based on copper in A213.

The strictest reading possible, would have us examine ASTM A450, (General requirements) since A 213 also cites A 450 as authority.

Here is what ASTM 450 has to say about "unspecified elements:"

4.2.1 For stainless steels ordered to under product specifications referencing this specification of general requirements, the steel shall not contain an unspecified element, other than Nitrogen, for the ordered grade to the extent that the steel conforms to another grade for which that element is a specified element having a rquired minimum content. For this requirement, a grade is is defined as an alloy described individually and identified by its own UNS designation in a table of chemical requirements within any specification listed with in the scope as being covered by this specification.

Milo comments: my take on the above is that the copper is acceptable per ASTM 's lack of mention, unless you find an UNS designation for a 304 with Copper for austenitic steel tubes somewhere. I do not know of such a 304LCU in tubing, nor do I know of a UNS number for this grade.

I do know that Ugne Stainless produces a bar steel grade 304Cu, but it does not have a UNS number, and it is not tubing.

In the absence of any word from the spec's I have mentioned above, and in the light of my experience shared immediately above, "the copper would be acceptable per the ordered specification" would be my testimony.

The ASTM Specifications cited provide no criteria for rejection based on Copper nor 'ammonia as an intended use.'

It is unrealistic to except "no copper" in any steel grade, where no copper means 0.0000% Cu. There are always residuals, traces, and 'tramp' elements found in our materials of construction, and with today's technology we can analyze to parts per billion we are literally counting atoms. I sympathize with the original poster, as I too find the copper levels much higher than I would expect. But they are not forbidden by ATSM specs cited.

Thanks to Doorman for assisting zagham with a private message to get us back onto this problem. And also to our dear colleague Abdul Halim Galela who originally provided the appropriate tables to this request.

Milo

Hello, Milo. Thank you for a very complete answer, worthy of another GA vote.

I have a question: If the .78% Cu proposed to be supplied is not outside of ASTM A213 TP304L, but it is an unacceptably high amount of copper for the intended purpose, how should the purchaser/specifier amend the spec to truly get tubing that fits the design parameter? Is this simply the incorrect spec?

The purchaser needs to quantify the maximum allowable wt% of Cu.

"Tubing, Wall, Length etc etc, ASTM A 213, grade TP304L, Maximum 0.30 wt % copper"

would get reviewed and probably accepted in my experience. If the PO said "0 wt % Cu" I'd no quote and let somebody else teach the customer the realities of their particular scrap fed economy.

In a real world where 0.15% is best available and HIGHEST COST from existing scrap using maximum amount of "virgin metal diluent."

In a prior life at a carbon and alloy meltshop I held copper to 0.40wt% max for merchant quality products; 0.35% max on plain carbon Special Bar quality/ and regular quality alloy steels, and 0.20% max on cold heading qualities.

I cannot ever remember seeing or signing a certificate of analysis where copper was only at the second or third decimal place in a scrap fed electric furnace process.

I am sure the scrap going into a stainless shop will have plenty of chances to have copper contained within. My review of ASTM A 276 (Stainless bars and shapes shows a number of grades with copper maxima or ranges.)

The Carpenter book is also silent on ammonia vs 304.

If the Purchase order came into my shop and we did contract review and i had cpK data or history, I could say Yay or nay; I would not be accepting orders for 0 copper. and wouldn't expect to say yes to any below 0.20 wt % without a fight. If they cant have "any copper" I would suggest they look at Glass.

This kind of engineering, in my opinion, is supposed to be done before the purchasing agents start placing orders, by the way. Not after the fact. I think that we are all overlooking the fact that the bid went for lowest cost to meet spec, rather than more expensive products where they might have better residual control... Had someone actually thought about residuals in the first place. After orders are placed is wrong time to look at supply chain capabilities.

Ultimately, these arguments are always about "money" and someone not realizing what "value" is. Like low residuals in the scrap to make the material.

Milo

Thankyou Doorman and Milo for your effective and prompt reply.

Problem is

We had used brand new ASTM A-213 TP-304 material U-tubes for re-tubing our Gas Water heat exchanger in October 2009. Shell side fluid of exchanger is cooling water (Pressure = 3.5 kg/cm2) and tube side fluid is ammonia vapors + synthesis gas (Pressure = 250 kg/cm2). Presently the heat exchanger is leaking.

We have carried out a detailed material analysis of the 22 spare U-bends available with us from the same lot of tubes. The test indicated the presence of copper up to 1.45%. The analysis was done at three different labs using different methods. We believe that the problem occurred because of the higher copper content in the material.

Now the query is that

1. What is the effect of liquid Ammonia/Ammonia vapors on TP-304 if it contains copper content as high as 1.45%?

2. On workout, i found that none of the manufacturer in europe agreed to provide 100% Cu free material. Those claiming 100% free copper material, their material test certificates show Cu content from 0.2 ~ 0.4 %. Now the question is that how much maximum copper content is acceptable for ammonia service for reliable operation i.e., avoiding ammonia attack.

3. Anyone who could tell about a vendor across europe, usa or japan who could provide material 100% free of copper?

Regards

Zagham

"Knowledge is not simply knowing its how to know and from where to know"

1.45% is Huge.

Are you certain the balance of the elements were in spec?

What is the moly content?

The 0.2-0.4% copper that you are being offerred is congruent with my experience.

As I said earlier, there is no such thing as 100% free of copper when you are counting atoms.

OK, given the data of 1.45% Copper, I think that I might have a rejection criteria. I need the chem cert for all elements on the lot that is leaking, I believe that there is a named grade which would meet the rejection criteria of astm a 450 (the general spec that A 213 cited) I gave yesterday, but you need to give me full chemistry from cert.

You really need to get me the chemical composition.

Milo