ASM Online Member Community

  • 1.  Effects of delta ferrite on 17-4PH stainless properties

    Posted 09-01-2021 10:22
    Hi everyone,

    Does anyone have any resources they can share about the effects of delta ferrite on 17-4 PH mechanical properties?  In particular, looking for the effect in MIM-produced 17-4 PH, but I'm interested in anything.

    Thanks!

    Dustin Lobner

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    Dustin Lobner
    Lead Materials Engineer
    American Orthodonitcs
    Port Washington WI
    (262) 737-5082
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  • 2.  RE: Effects of delta ferrite on 17-4PH stainless properties

    Posted 09-02-2021 10:09
    Hi, Dustin,

    I passed your request to Dr. Damian Kotecki, coauthor of "Welding Metallurgy and Weldability of Stainless Steel"  who provided the following:

    Ferrite in 17-4PH weld metal reduces tensile ductility because it is much weaker than martensite.  So strain concentrates in the ferrite, causing low ductility.  Most producers of 17-4PH (ER630) filler metal are aware of this and push composition to low chromium and high nickel to limit delta ferrite.  Then the composition comes close to overlapping with that of 15-5PH filler metal which is not classified by AWS but is classified by AMS 5826.  15-5PH is a better filler metal for 17-4PH.

    See his website: www.damiankotecki.com.  I expect that he would be happy to speak with you directly.

    Hope that helps.  



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    Walter Sperko
    President
    Sperko Engineering Services Incorporated
    Greensboro NC
    (336) 674-0600
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  • 3.  RE: Effects of delta ferrite on 17-4PH stainless properties

    Posted 09-02-2021 14:30
    Hi Walter,

    That is exactly the type of info I was looking for.  Also had someone direct message me and recommend some articles, so I think I should be good.

    Getting set up to etch with 20% NaOH and 20VDC to look at the ferrite amounts in particular.

    Thanks!

    Dustin

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    Dustin Lobner
    Lead Materials Engineer
    American Orthodonitcs
    Port Washington WI
    (262) 737-5082
    ------------------------------