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searching for specs on an obsolete material reference

  • 1.  searching for specs on an obsolete material reference

    Posted 07-26-2021 09:22
    I'm searching for material specifications from a legacy component part to help establish a baseline on original design intent of the part. The original material specification from the late 1960's and early 1970's was simply stated on the part drawing as "silicon brass alloy #30". I have discovered that this was intended to reference an alloy product from Arwood Precision Casting Corporation (or perhaps variations on that name as the company evolved over time), and that it was most likely intended to be used with an investment casting process for this particular part. To date I have been unable to locate a material specification with mechanical properties within our company's archives (though still digging). Any help in finding a historical brochure or spec sheet from Arwood (or APC) would be much appreciated.

    I have reviewed ASTM B30-2020 (current edition) which lists several alloys for silicon brass (e.g. UNS C87400, C87500, C87800, C87845, C87850). But at this point in time I am not certain which specific alloy and which thermal profile (casting process) would correspond to the material used for this particular part, and then most importantly what were the expected mechanical properties (minimum and/or typical values for tensile yield and tensile ultimate strength, and if available fatigue life properties).​

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    Phillip Johnson
    Daikin Applied
    Staunton VA
    (540) 245-0000
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  • 2.  RE: searching for specs on an obsolete material reference

    Posted 07-27-2021 08:48
    Dear Phillip,

    What type of component do you have? any photo do you have ?

    Hope we could help you!, I was working with brass and bronzes but mor antique..., but if I can or some of the colleagues of the group will be pleasure!

    Do you make a chemical analysis to the component, like a XRF? Just to have a complete data of the alloy, also XRF analysis are not invasive to the surely we are speaking of a historical piece.

    Thanks for your sharing,


    ------------------------------
    [Patricia Silvana] [Carrizo]
    [Ms.]
    [Chemical Engineer]
    [Archaeometallurgy Area - UTN FRM]
    [Mendoza] [Argentina]
    [+542615577229]
    ------------------------------



  • 3.  RE: searching for specs on an obsolete material reference

    Posted 07-27-2021 16:09
    Patricia - 
    My inquiry is not about a single historical piece, the component continues to be used for current production but due to changing suppliers to source the part several times over the decades I have concern that the current material in use may not be the same as the original choice, due to the vague description of the material allowing several substitutions to be made. I do know the location of a few samples that would be of a known age or vintage (contained within an assembly of parts used for training purposes). So if all else fails in my specification search then perhaps I borrow one of those old samples and conduct some testing (non-destructive and/or destructive) to better determine the original mechanical properties and chemical composition of the alloy.

    Best regards,

    ------------------------------
    Phillip Johnson
    Daikin Applied
    Staunton VA
    (540) 245-0000
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  • 4.  RE: searching for specs on an obsolete material reference

    Posted 07-27-2021 19:30
    Phillip,

    Yes, exactly! If you dont find any link to this piece, yes you will have to do some reverse engineering.

    I suggest to do a chemical analysis like with a portable XRF also its quite nice because you can measure on the piece without stop the process, and also do the analysis on these pieces that belong to the box of samples.

    With this you could compare with standarized alloys, mabe the piece was did without a standard norm, really rare case, because we are speaking of a piece from 50 years ago only, but could be a case. And then try with a hardness test and with this I think you will have so much info.

    Hope I am helpful.

    ------------------------------
    [Patricia Silvana] [Carrizo]
    [Ms.]
    [Chemical Engineer]
    [Archaeometallurgy Area - UTN FRM]
    [Mendoza] [Argentina]
    [+542615577229]
    ------------------------------



  • 5.  RE: searching for specs on an obsolete material reference

    Staff Liaison
    Posted 07-27-2021 08:52
    Phillip,

    I searched the ASM Alloy Digest repository. I found several data sheets for silicon brass alloys from that general era (such as these), but none from Arwood or that specifically mention an alloy #30.

    Scott


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    Scott Henry
    Senior Content Engineer
    ASM International
    Materials Park OH
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  • 6.  RE: searching for specs on an obsolete material reference

    Posted 07-27-2021 16:09
    Thanks for taking the time to search!

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    Phillip Johnson
    Daikin Applied
    Staunton VA
    (540) 245-0000
    ------------------------------



  • 7.  RE: searching for specs on an obsolete material reference

    Metro NY/NJ Chptr Admin
    Posted 07-27-2021 16:10
    Have you tried contacting the Copper Development Association?

    https://www.copper.org/

    They may have some old information. 

    Do you have an original part? Would you be able to analyze it? 

    As I understand it, at that time many foundries working in these types of alloys still had their own proprietary alloys - the "silicon brass alloy #30" in your case sounds like it could well be an example of this. Unless you either find original data or an original part that you can examine, you are not likely going to find the answers to your questions. You may have to reverse engineer the product through knowing what it's application is. 

    I've faced this same situation working in these older copper based alloy systems. Good luck and please let us know how you make out.

    dj




    ------------------------------
    David Jones
    Senior Principal Materials Engineer
    Stryker Orthopeadics
    Mahwah NJ
    (914) 469-2958
    ------------------------------



  • 8.  RE: searching for specs on an obsolete material reference

    Posted 07-27-2021 17:29
    Yes, a colleague of mine contacted the vice president of the CDA. He searched their database of registered copper containing alloys, both active and inactive, and came to the conclusion that it was likely a proprietary alloy unique to Arwood Precision Casting Corporation. We also sent chemical composition test results from a current production sample and it did not match any of the active alloys in the CDA database. Per another reply in this discussion thread, I had expressed concern that the actual production material might have changed over the decades as the part supplier and foundry changed, but the unique composition of the alloy currently in use may in fact mean that the recipe was passed along in the process of supplier changes. So we will be investigating further with the current supplier to better understand the history and how they interpret our drawing requirement of "silicon brass alloy #30".

    I do know the location of a few sample parts that would be of a known age or vintage (contained within an assembly of parts used for training purposes). So if all else fails in my specification search then perhaps I borrow one of those old samples and conduct some testing (non-destructive and/or destructive) to better determine the original mechanical properties and chemical composition of the alloy.

    ------------------------------
    Phillip Johnson
    Daikin Applied
    Staunton VA
    (540) 245-0000
    ------------------------------



  • 9.  RE: searching for specs on an obsolete material reference

    Posted 07-27-2021 17:47

    Dear Phillip,

     

    I do like questions like this – they remind me of why I became a metallurgist. Normally I am looking at nineteenth century and earlier but I do occasionally have requests like this.

     

    The key question is, do you have one or more examples of the original components or are you just dealing with documents? If the former, then a sample, SEM or microprobe analysis, optical metallography and a hardness test will answer your questions for a much smaller outlay than the staff time spent in searching archives. It will also enable you to estimate whether it matches any current spec. Of course, it may not match any spec. of the period either; the guy on the foundry floor might have had his own ideas, whatever management said.

     

    Regards,

    Peter Northover



    ------------------------------
    Peter Northover
    Retired
    University of Oxford
    +44 1865 820543
    peter.northover@retired.ox.ac.uk
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  • 10.  RE: searching for specs on an obsolete material reference

    Posted 08-05-2021 10:30
    I do know the location of a few sample parts that are likely of a known age or vintage (contained within an assembly of parts used for training purposes). So if all else fails in my specification search then perhaps I borrow (or sacrifice permanently) one of those old samples and conduct some testing (non-destructive and/or destructive) to better determine the original mechanical properties and chemical composition of the alloy.

    ------------------------------
    Phillip Johnson
    Daikin Applied
    Staunton VA
    (540) 245-0000
    ------------------------------



  • 11.  RE: searching for specs on an obsolete material reference

    Metro NY/NJ Chptr Admin
    Posted 07-28-2021 08:30
    I am not at all surprised the CDA told you it was likely a proprietary alloy. From your original description it certainly sounded that way. I would not count on the formula having been passed along. But in the transfer between one supplier to another enough information may have been given that the second supplier used an alloy that would give equivalent performance results. 

    So is this alloy roughly a 81 Cu-4 Si- 15Zn? What is the component used for, a pump? 

    I think you need to look carefully at the component design to understand your potential performance requirements and then look to see where you might be making mold adjustments to accommodate either part performance requirements or casting integrity requirements. Then with a good handle on those constraints, I'd then develop a plan for the metallurgical examination. They may have had lots of tricks used in the casting process depending upon the part geometry and end use.

    dj

    ------------------------------
    David Jones
    Senior Principal Materials Engineer
    Stryker Orthopeadics
    Mahwah NJ
    (914) 469-2958
    ------------------------------



  • 12.  RE: searching for specs on an obsolete material reference

    Posted 08-05-2021 10:45
    We are closely evaluating current and newer designs of this component type but the applied loads and duty cycles are not well defined nor easily measured with reasonable measurement uncertainty. Fatigue is the failure of concern and some prototype testing has revealed a lack of robust design. Gross over-design with a high safety factor to failure has significant penalties for performance of the product, so it is a balancing act.

    As a parallel path of investigation we are reviewing an older design that had a successful field history to use as a case study or baseline point of reference to better understand the safety factor of the older design and what made it work. The older component design continues to be used for current production on a limited basis, but due to changing suppliers to source the part several times over the decades I have concern that the current material in use may not be the same as the original choice, hence digging into and searching for old specifications. A challenge with this case study is that our end-use application operating range has increased over the decades, so the load profiles experienced by the older design may not be the same as current products in use.

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    Phillip Johnson
    Daikin Applied
    Staunton VA
    (540) 245-0000
    ------------------------------



  • 13.  RE: searching for specs on an obsolete material reference

    Metro NY/NJ Chptr Admin
    Posted 08-06-2021 08:35
    Working with legacy products is always an interesting challenge.

    dj

    ------------------------------
    David Jones
    Senior Principal Materials Engineer
    Stryker Orthopeadics
    Mahwah NJ
    (914) 469-2958
    ------------------------------