In reviewing usage statistics for ASM Handbooks in the ASM Digital Library, I noticed that Corrosion Characteristics of Copper and Copper Alloys was the article in the Metals Handbook Desk Edition, 2nd ed., that received that most usage in 2019 and also so far in 2020. It has about five times the usage of an average article in that volume. Any ideas what might be driving the interest in that particular topic?
The article reviews the forms of corrosion and the general performance of copper in each. It discusses the effects of alloy compositions and alloy selection for specific environments. Table 4 is a very large chart that gives corrosion ratings for nine classes of copper alloys in more than 120 different media. The ratings are excellent or good in most media, but there are a few harsh environments (such as nitric acid) where it performs poorly.
It would be interesting to know the various reasons ASM Desk Editions users turn to this article. Is it to diagnose a corrosion issue or failure, to develop a corrosion protection strategy, or to select an appropriate alloy for a given application?
As a reminder, access to the full text of the ASM Desk Editions is provided as an ASM membership benefit. ASM members just need to log in using their ASM site credentials.
June, That's interesting. Is the relative failure rate of yellow brass due to its higher alloy (and lower copper) content? Would the SCC failures be fewer in number if a higher copper brass was selected?
Scott,I also deal with this daily and agree that this is a big and fascinating issue. From a metallurgical standpoint the solution (as you suggested) is simple - use brass with a lower zinc/higher copper content and both SCC and dezincification go away. Unfortunately, it seems like some major plumbing code and spec decisions have already been made without serious regard for metallurgical implications and they are pretty set-in-stone, so yellow brasses are often explicitly allowed and are easier for manufacturers to work with. All this makes it a really challenging to rebut an argument of "the code says this is OK, so how can there be an issue?" Anyway, I'm not sure if this is related to the increase in traffic (I hope so though!), but I think it is an interesting issue to keep track of.
NSF 14/ANSI 61 does not address torque requirements for fittings; it is a standard which provides guidance on compatibility of chemicals used in water treatment and disposal. With respect to residual stresses, there are stress relieving temperatures associated with brass alloys. The purchaser, in most cases a large distributor, would have to specify stress relief or verify if the product manufacturer performs this process after manufacture. I have found that many cast products, such as valves, coming in from China have no stress relief treatments, and they often split apart after sustaining pressure.
Mail for Windows 10
Please see attached. The material is C260 annealed temper.
Was sent to us by our customer with following message;
"…We bought the material in question from you in June 2017. We sold it to a customer in May 2019. Customer notified us of this concern in April 2020.
Customer's quality department is claiming that both parts in attached pic came from the same shipment. Parts were laser cut and the end use is a Fey Shield they believe."
We asked about protective atmosphere during laser cutting. The answer is:
" Our laser operation is not in a non-oxidizing atmosphere but we do use nitrogen as a shielding gas."
Please advise how to design an investigation.
Thank you in advance.
Larry, Perhaps because Copper is in the noble metals column, but maybe as a knight or bishop, rather than as a king or queen. The gap in perception versus reality may be driving the high usage of the article.Agree: Copper and nitric acid can produce various nitrogen oxides, only one of which is laughing gas, the others are nothing to laugh at, at all.You have stirred some interesting discussions.
It also mentions later that Muntz later developed fasteners of his composition that did not dissolve (as would happen from a corrosion couple with iron) further enhancing his commercial gains.