Presence of Cu in SS 316L
Presence of Cu in SS 316L
(OP)
We have procured SS 316L pipe (4" Sch. 160)for our Urea plant. We have now tested some random lengths of the pipe and the result of one of them is as follows:
Cr = 16.78 %
Mn =1.39 %
Mo = 2.19 %
Ni = 10.59 %
Cu = 0.8 %
Fe = 68.25 %
The above composition seems perfect except the presence of Copper. Can anyone advise if the presence of Cu is acceptable?
Please note that the alloy analyzer cannot detect Carbon therefore the reading of Carbon is not given.
Regards
Cr = 16.78 %
Mn =1.39 %
Mo = 2.19 %
Ni = 10.59 %
Cu = 0.8 %
Fe = 68.25 %
The above composition seems perfect except the presence of Copper. Can anyone advise if the presence of Cu is acceptable?
Please note that the alloy analyzer cannot detect Carbon therefore the reading of Carbon is not given.
Regards





RE: Presence of Cu in SS 316L
I am not sure of this, but the copper presence could be an issue for corrosion resistance, as copper is more active, from a galvanic point of view, than SS 316L .
RE: Presence of Cu in SS 316L
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Presence of Cu in SS 316L
Copper shouldn't be there as already written by others. The manganese content seems to be rather low, too. Where did you buy it, in the US or abroad? Keep in mind that the AISI code fits to various DIN or ISO material codes and some may allow some copper content. But at the end of the day it depends upon what code your supplier had confirmed.
RE: Presence of Cu in SS 316L
The composition listed did not look like anything that I saw in A 182 when searching for copper.
RE: Presence of Cu in SS 316L
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Steel is considered to be carbon steel when no minimum content is specified or required for chromium, cobalt, columbium [niobium], molybdenum, nickel, titanium, tungsten, vanadium or zirconium, or any other element to be added to obtain a desired alloying effect; when the specified minimum for copper does not exceed 0.40 per cent; or when the maximum content specified for any of the following elements does not exceed the percentages noted: manganese 1.65, silicon 0.60, copper 0.60. Carbon steels are normally classified as shown below.
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High-strength low-alloy (HSLA) steels, or microalloyed steels, are designed to provide better mechanical properties than conventional carbon steels. They are designed to meet specific mechanical properties rather than a chemical composition. The chemical composition of a specific HSLA steel may vary for different product thickness to meet mechanical property requirements. The HSLA steels have low carbon contents (0.50 to ~0.25 weight percent C) in order to produce adequate formability and weldability, and they have manganese contents up to 2.0 weight percent. Small quantities of chromium, nickel, molybdenum, copper, nitrogen, vanadium, niobium, titanium, and zirconium are used in various combinations.
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Some uses are given here,
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Is the pipe certified as ASTM A316 or not? If so, then I would worry about if it is suitable to your process or not.
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Presence of Cu in SS 316L
RE: Presence of Cu in SS 316L
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Presence of Cu in SS 316L
RE: Presence of Cu in SS 316L
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Presence of Cu in SS 316L
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Presence of Cu in SS 316L
RE: Presence of Cu in SS 316L
Since we are talking about 316L pipe, I'm assuming that the applicable specification is ASTM A312 "Standard Specification for Seamless and Welded Austenitic Stainless Steel Pipes".
According to ASTM A312, for Grade 316L, Manganese is listed as 2% and Copper is shown as "...". Consequently, any value for Manganese not greater than 2% if permissible and there is no specified minimum or maximum for Copper.
As a result (as already indicated by SJones), the material you were supplied would be in accordance with ASTM A313 Grade 316L and could not rightfully be rejected on the basis of the chemistry unless you had provided supplemental requirements with the purchase order.
As to the question of whether the Cu is a good thing or a bad thing, I'll leave that to the qualified metallurgists.
RE: Presence of Cu in SS 316L
For me I can't agree this thinking, accepting 0.8% Cu means you are prepared to accept any other contaminant that has been introduced during manufacture. I believe that if it is not listed it is excluded.
RE: Presence of Cu in SS 316L
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Presence of Cu in SS 316L
Checking ASTM A 312, Table 1 Chemical Requirements includes a column for copper. The composition percentage includes a note B that reflects the value is the maximum unless otherwise indicated. Type 316L is blank under copper. This would suggest that any copper is out of specification for ASTM A 312 type 316L. See comments in this and another post about ASTM A 941, Steel Alloy Terminology.
This may be my first look at ASTM A 941 in a while. The definition for stainless steel only addresses the mass percent with a minimum chromium content and a maximum carbon content. With a column for copper it would not be an unspecified element.
I don't have ASTM A 313.
RE: Presence of Cu in SS 316L
RE: Presence of Cu in SS 316L
I don't think you'd want to spec 304 in projects carrying or storing jet fuel and the likes, so what Artisi says makes sense too.
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Presence of Cu in SS 316L
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Presence of Cu in SS 316L
htt
Is it possible your test was done near a weld?
RE: Presence of Cu in SS 316L
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Presence of Cu in SS 316L
Which edition of A312 have you got? In my 2002 copy, Note B just says "Maximum, unless otherwise noted" but it doesn't say anything about what the ellipses per se actually mean (either none at all, or no restriction).
This is kind of bugging me so I tried calling ASTM this afternoon and got passed around a couple of people, none of whom knew what I was asking about nor had an answer.
I consulted with a couple of materials engineers I know and received the response that unless a numeric value is listed, there is no minimum or maximum to the element. The element is shown because a single table is being used for a number of different grades and some of the grades have that element controlled so there has to be a column for it. For other grades, where the element is "unspecified" no numeric value is listed.
I'd be as keen as everyone else to find a proper definition of the ellipses somewhere in one of the ASTM standards ...
RE: Presence of Cu in SS 316L
Steve Jones
Materials & Corrosion Engineer
http://www.linkedin.com/pub/8/83b/b04
RE: Presence of Cu in SS 316L
RE: Presence of Cu in SS 316L
RE: Presence of Cu in SS 316L
RE: Presence of Cu in SS 316L
**********************
"The problem isn't working out the equation,
its finding the answer to the real question." BigInch
http://virtualpipeline.spaces.live.com/
RE: Presence of Cu in SS 316L
RE: Presence of Cu in SS 316L
My guess is that this is from poor scrap segregation.
I am not so worried about the Cu as I am the possibility of Zn, Sn and other metals.
The ellipses technically means: this is from A941:
ellipsis, n—in a tabular entry, three periods (...) that indicate that there is no requirement.
Cu does help corrosion resistance is some cases (H2SO4), and it hurts in others.
This level of Cu can make welding more difficult, more prone to discoloration and porosity.
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