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Copper alloy - Brass Specs

  • 1.  Copper alloy - Brass Specs

    Posted 07-31-2024 06:31

    A customer has specified two copper alloys on a part drawing sent to us. The first one is 'PC-12 SB Brass' It has a tensile strength of 63 - 70 Ksi and elongation of 30-34 % in a 50 mm specimen. The electrical conductivity is 35 - 38% IACS. The second one is CDA 815 with tensile strength of 54-59 Ksi, elongation of 20-25 % on a 50 mm specimen and IACS - 70%. The only additional information I have is PILAD. I guess, this is the name of the original manufacturer which does not exist anymore.  

    I am unable to find a UNS number or any other standard equivalent. I will greatly appreciate if anyone can help me with finding the UNS equivalent grade or tell me that this is a variant of a std grade. 



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    Lalit Kumar Pahwa
    Managing Director
    Pahwa MetalTech Pvt Ltd
    Pune
    +91 98500 20000
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  • 2.  RE: Copper alloy - Brass Specs

    Posted 07-31-2024 10:31

    Hello

    A good resource to use is the Copper Developement assocaition (CDA).

    Official Site of Copper Development Association, Inc. (USA)

    Craig



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    Craig Leabch
    Principal Tooling Engineer
    Cretex Medical
    Brooklyn Park MN
    763-703-5000
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  • 3.  RE: Copper alloy - Brass Specs

    Posted 08-01-2024 07:34

    Thanks Craig. I searched the CDA website and their data sets. Couldn't find what I was looking for. Anyway thanks for your reply. 



    ------------------------------
    Lalit Kumar Pahwa
    Managing Director
    Pahwa MetalTech Pvt Ltd
    Pune
    +91 98500 20000
    ------------------------------

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  • 4.  RE: Copper alloy - Brass Specs

    Posted 07-31-2024 12:26

    In some cases, CDA alloy names have been used as the basis for UNS designations. So, CDA 815 may correspond to UNS C81500. 

    Information about UNS C81500 is provided in various online sources and in the ASM Digital Library



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    Scott Henry
    Director of Content and Publishing
    ASM International
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  • 5.  RE: Copper alloy - Brass Specs

    Posted 08-01-2024 07:35

    Thanks Scott. Will search the ASM Digital Library.



    ------------------------------
    Lalit Kumar Pahwa
    Managing Director
    Pahwa MetalTech Pvt Ltd
    Pune
    +91 98500 20000
    ------------------------------

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  • 6.  RE: Copper alloy - Brass Specs

    Posted 08-01-2024 07:36

    Copper.org can be a good source. C815 is a chrome copper and the values match close to those you mentioned. in case of PC-12, It looks like a private specification but equivalent could be available. 



    ------------------------------
    Muthukumarasamy Sadayappan
    Research Scientist
    Canmet MATERIALS, Natural Resources Canada
    Hamilton ON
    (905) 645-0782
    ------------------------------

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  • 7.  RE: Copper alloy - Brass Specs

    Posted 08-01-2024 08:23

    Thank you Mr Sadayappan. Will search Copper.org once more.



    ------------------------------
    Lalit Kumar Pahwa
    Managing Director
    Pahwa MetalTech Pvt Ltd
    Pune
    +91 98500 20000
    ------------------------------

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  • 8.  RE: Copper alloy - Brass Specs

    Posted 08-05-2024 15:09

    Yes, CDA 815 in modern times refers to UNS C81500 which is a high copper alloy with  Cr (0.40% - 1.5%). You can look in the UNS book that defines alloy compositions (Metals & Alloys in the Unified Numbering System, 14th Edition HS-1086/2023) for a cross-reference for this alloy to determine what spec to use that meets the specs you received. As for PC-12, I have not found anything about this alloy but you may have good luck looking in the ASM reference book "Worldwide Guide to Nonferrous Alloys".  Could SB be referring to satin brass?



    ------------------------------
    Aaron Tanzer
    Principal Research Engineer
    University of Dayton Research Institute
    Beavercreek OH
    (407) 247-9557
    ------------------------------

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  • 9.  RE: Copper alloy - Brass Specs

    Posted 08-07-2024 08:08



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  • 10.  RE: Copper alloy - Brass Specs

    Posted 08-07-2024 08:49

    If the table attached by David is correct the alloy PC-12 could be UNS C86100; but the strength will be higher and conductivity will be lower for C86100 than prescribed above. If you need 30-35% IACS then the Zn and Al content need to be lower.



    ------------------------------
    Muthukumarasamy Sadayappan
    Research Scientist
    Canmet MATERIALS, Natural Resources Canada
    Hamilton ON
    (289) 922-8567
    ------------------------------

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  • 11.  RE: Copper alloy - Brass Specs

    Posted 08-13-2024 07:08

    The table sent by David is correct. That is the table we found. I will look up C86100, but feel CDA 864 which is a Cu-Zn-Al alloy is closer in specs to PC-12. If the Zn -Al content is lowered experimentally, the conductivity will probably increase due to higher copper % and the right heat treatment. Thanks for your help Mr Sadayappan



    ------------------------------
    Lalit Kumar Pahwa
    Managing Director
    Pahwa MetalTech Pvt Ltd
    Pune
    +91 98500 20000
    ------------------------------

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  • 12.  RE: Copper alloy - Brass Specs

    Posted 08-13-2024 07:01

    David,

    Yes thats the one. We have this table - probably from the non-existent manufacturer's website. You will notice that PC#12-SB does not have an equivalent grade mentioned against it, nor do we have the composition. This is the data we are trying to find out.



    ------------------------------
    Lalit Kumar Pahwa
    Managing Director
    Pahwa MetalTech Pvt Ltd
    Pune
    +91 98500 20000
    ------------------------------

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  • 13.  RE: Copper alloy - Brass Specs

    Posted 08-13-2024 06:54

    Thanks Aaron. PC-12 is a manufacturer spec. Unfortunately, the manufacturer doesn't exist anymore and hence the search for an equivalent.



    ------------------------------
    Lalit Kumar Pahwa
    Managing Director
    Pahwa MetalTech Pvt Ltd
    Pune
    +91 98500 20000
    ------------------------------

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  • 14.  RE: Copper alloy - Brass Specs

    Posted 08-14-2024 12:15

    Are you sure about that? PC-12 looks like a proprietary alloy that is produced by Perma-Cast but they still seem to be in business and their catalog that includes available product forms is online. They are located in Pueblo Colorado.



    ------------------------------
    Aaron Tanzer
    Principal Research Engineer
    University of Dayton Research Institute
    Beavercreek OH
    (407) 247-9557
    ------------------------------

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  • 15.  RE: Copper alloy - Brass Specs

    Posted 08-14-2024 19:46
    Lalit,
    This is an interesting situation.  I've have had to search up old alloys on occasion so will offer comments.

    Others pointed out that the old CDA numbers are directly translated to UNS numbers.  Chromium coppers were used when electrical conductivity needed to be maintained on the high side while strength was also a premium, an uncommon combination of properties in the copper field.  These and beryllium coppers are among the few choices in such situations.

    The other grade called out in that table is likely to be a private or at least non-industrial-standard grade, or possibly obsolete.  Other comments below.

    If a customer is asking you to make something, they are responsible for telling you what to use!  If the customer no longer knows what the original spec means they, and you, are working to what I call "dead guy's rules".  It's not uncommon for this to happen but it means that you must take steps to not be to blame for any problems.  This may involve additional contractual language for the purchase.  If they are asking you to assume design responsibility by choosing a grade, you should know what the working conditions are, and have someone responsible for evaluating the alloy selection, and you should be paid for these design decisions!  To do such a selection, you should know why it is that they are asking for a new part - is this reverse engineering of an obsolete part?  Did something recently fail and they just want "another one like that last one"?  If there is a recent failure, you could ask to see and analyze the old part for chemistry and hardness to determine whether a like-for-like is the right choice.  Was the service life satisfactory?  And so on.  Protect your own interest from unwanted liability.

    As far as the alloy choice, from the table supplied the notable numbers to me are that the yield strength is low, while the conductivity is middling, and the modulus of elasticity is notably low.  Copper alloys are usually around 15 to 16 x10^6 psi modulus, so the value shown of 11 means that there is a lot of alloying, and mostly likely the listed zinc is a large fraction.  From a graph in my 1961 Metals Handbook, copper-zinc alloys have dropped about 1/3 of their modulus when alloyed with 15% or more Zn.  However the conductivity also drops such that you cannot expect 35% IACS with greater than about 16% Zn.   So you're in the yellow brasses still, with maybe a small add of aluminum for increased atmospheric corrosion resistance.

    I found no grades in a quick search with Cu-Zn-Al other than arsenical aluminum brass C68700, but its %IACS value is only 23 in the Copper.org reference I used.  C67800 does also show Cu-Zn-Al but is obsolete apparently with almost no other data.  So for your alloy substitution search, if the application calls for conductivity as a crucial property (per the customer's requirements!) then sort the table of coppers by IACS and following that try to find adequate strength.

    Finally, though it probably doesn't apply here, sometimes a leading "SB" designation means an ASTM copper alloy (begins with "Bnnnn") that is adopted for ASME Code requirements, which has a prefix S added.  ASTM B12 was Copper Rods for Locomotive Staybolts. 

    Paul Tibbals, P.E. (retired)



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  • 16.  RE: Copper alloy - Brass Specs

    Posted 08-15-2024 07:55
    SB is the designation for nonferrous alloys in the ASME Boiler and Pressure Vessel Code (BPVC). For Example, SB-61 is a Specification for Steam or Valve Bronze Castings. These are adopted from ASTM B specifications and are similar to them.

    The problem of shorthand material designations on old drawings is a recurring problem. You can't fix the past, but going forward, attempts should be made to provide complete, non-proprietary designations on part drawings. Since even society specifications, preserving the specification itself in the design file is a prudent precaution. 

    --
    John Grubb



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  • 17.  RE: Copper alloy - Brass Specs

    Posted 08-16-2024 04:37

    Thank you Paul for a detailed reply to my query. 

    You are absolutely right on several counts. The customer used this part, which was designed by someone who retired decades ago; there is no organizational memory of where this spec came from. The problem was compounded by the fact that the user has been buying this component from China for two decades and the engineers/managers managing the show have no clue what they are buying. They have been buying from the supplier for a long time and there was no problem with the part and hence never had to ask questions. Now the customer wants to source from India, and we are asking all the questions and trying to find answers. The engineers in the customer organization have no answers and probably do not want to make an effort to find them. 

    Your advice about adding 'protectionist' clauses in the purchase agreement is the right way forward. We will do our research and add another layer of safety with this clause, just-in-case. 



    ------------------------------
    Lalit Kumar Pahwa
    Managing Director
    Pahwa MetalTech Pvt Ltd
    Pune
    +91 98500 20000
    ------------------------------

    IMAT Conference & Expo


  • 18.  RE: Copper alloy - Brass Specs

    Posted 08-19-2024 12:48

    The properties you provided really indicate the specified material is proprietary Perma-Cast PC-12. I wonder if your supplier was really supplying this alloy, or whether they just were supplying some imitation. I again suggest you contacting Perma-Cast directly regarding getting the specified material. Your alternative is to perform an engineering review to find an acceptable material meeting the operating and structural needs of your actual application.



    ------------------------------
    Aaron Tanzer
    Principal Research Engineer
    University of Dayton Research Institute
    Beavercreek OH
    (407) 247-9557
    ------------------------------

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  • 19.  RE: Copper alloy - Brass Specs

    Posted 08-22-2024 08:27
    Aaron,

    The alloy specs I am looking for is not made by PermaCast. Permacast is a part manufacturer and uses PC as a suffix for some of their catalogue items. It has no connection to any alloy spec.

    Thanks for your comments, though.

    Sincerely

    Lalit Kumarr Pahwa

    Managing Director & CEO

    Pahwa MetalTech Pvt Ltd

    CIN: U28113PN2014PTC158369

    Chakan, Pune 410501 India

    Mo: +91 98500 20000




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  • 20.  RE: Copper alloy - Brass Specs

    Posted 08-20-2024 15:57

    Sorry to sound somewhat sarcastic, but there have been many well thought out responses; however, the important fact that has been clearly established is that PC-12 SB is a proprietary alloy of Perma-Cast.  You will not find the composition published in the open literature and it is unlikely that an honorable professional would give it to if they were to know it. You have only three choice,1. direct your customer to Perma-Cast for them to make the part, 2. seek a license from Perma-cat to produce their alloy or 3. do the Materials Engineering to find a suitable substitute commercially available alloy that meets the customer's physical and mechanical requirements.

    Ken    



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    Kenneth Kubarych
    Solar Turbines Inc.
    Del Mar CA
    (858) 204-2121
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  • 21.  RE: Copper alloy - Brass Specs

    Posted 08-20-2024 19:21

    It seems like the OP's info request has been satisfied.

    Maybe someone did mention in the thread that the original alloy was from Perma-Cast, I missed that.  Makes sense in the designation. The current company that comes up with that name makes swimming pool hardware, so maybe the company is defunct, or the name was bought or the company changed hands or commercial focus, or the trademark was lost due to the company not defending it.

    An alloy's composition can be patented, and the name can be trademarked.  Patents have a finite lifetime, and the comments made suggest that it's been a long time since the alloy was called out.  But the composition is much more often held as a trade secret. Though I have handbooks full of industrial but non-standardized alloys that have generic compositions listed - see Woldman's Engineering Alloys, on offer here at ASMI, for example.

    One cannot use the originator's trademarked name for the alloy.  But anyone competent with a metallograph and an analyzer can probably get well along to duplicating it if part of the original is at hand, and it isn't unlawful if not violating a patent.  Does that give someone the expertise in the development and production equivalent to the originator?  Of course not. The OP was asking for a source of the material to supply it to his customer.  As I suggested the OP, and his customer, need to evaluate whether mere duplication to a "dead guy's rules" is good enough.



    ------------------------------
    Paul Tibbals
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  • 22.  RE: Copper alloy - Brass Specs

    Posted 08-22-2024 08:21
    Thanks Paul,

    The alloy we are looking for is NOT from PERMACAST. It is just a coincident that the alloy spec has a PC in its name. The Permacast Website that colleagues on the group have visited, gives no indication that they ever manufactured any alloy. Some of the parts they make are numbered/identified with a suffix PC.

    The Company that did make this alloy was known as PIAD, which does not exist anymore. The alloy is not patented, if it was, we would have found a patent. Assuming it did exist, I am sure it expired many years ago. So we are now re-inventing the wheel. Thank you for mentioning Woldman's Engineering Alloys. I will try to find and see if this helps. 

    Anyway, thank you for your comments and support.

    Sincerely

    Lalit Kumarr Pahwa

    Managing Director & CEO

    Pahwa MetalTech Pvt Ltd

    CIN: U28113PN2014PTC158369

    Chakan, Pune 410501 India

    Mo: +91 98500 20000




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  • 23.  RE: Copper alloy - Brass Specs

    Posted 08-22-2024 15:58
      |   view attached

    FYI, I found the attached on-line. I believe it qualifies as a published document. Perma-Cast location and phone included



    ------------------------------
    Gerson Ecker
    ECKER-ERHARDT CO INC
    Chicago IL
    (312) 848 2347
    ------------------------------

    Attachment(s)

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  • 24.  RE: Copper alloy - Brass Specs

    Posted 08-23-2024 06:40

    Thanks Gerson,

    As I mentioned in an earlier post, we found this table and cannot find PermaCast - the alloy manufacturer. I will try once again with the phone number you have provided. Thank you for your effort and help.



    ------------------------------
    Lalit Kumar Pahwa
    Managing Director
    Pahwa MetalTech Pvt Ltd
    Pune
    +91 98500 20000
    ------------------------------

    IMAT Conference & Expo


  • 25.  RE: Copper alloy - Brass Specs

    Posted 08-23-2024 16:10

    Here is a link to the Perma-Cast Non-Ferrous Permanent Mold Castings website

    https://www.perma-cast.com/

    Here are a couple of links to where you can access the Perma-Cast table that lists PC #12-SB Brass

    Perma-Cast Selection Guide I Export, PA

    Alloy Selection Guide.xlsx (hibu.com)



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    Barry Dietz
    Principal Engineer
    Komatsu
    Peoria IL
    (309) 672-7131
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