ASM Online Member Community

  • 1.  Cold-working aluminum holes

    Posted 04-07-2022 05:49
    One of our product lines - which operates the C-144 fixed wing - is installing Ti-6-4 hi-locks into 2024-T3 wing skin. This is an interference fit with an additional clamping force. What is the stress limit in the aluminum at the interface with the Ti fastener? In order to avoid cracking? Do you have any resources to refer me to in order to illuminate the situation?

    William Weimer
    Senior Metallurgist and Materials Engineer
    United States Coast Guard
    Virginia Beach VA
    ASM Handbook 23A

  • 2.  RE: Cold-working aluminum holes

    Posted 04-08-2022 10:05
    Edited by Edward White 04-08-2022 10:05

    There is a lot more information needed to answer your question. Are you concerned about cracking during installation or during its useful lifetime? Those are two different answers.

    Edward White, P.E.

    ASM Handbook 23A

  • 3.  RE: Cold-working aluminum holes

    Posted 04-11-2022 10:42
    Hi William,
    I spotted the title of your post "Cold-working aluminum holes".
    Are you referring to the cold expansion technique for hole processing in Aluminum alloys? In that case you are creating compressive residual stresses around the hole and thus providing additional resistance in the Al structure to withstand the stress produced by the Ti-alloy fastener assembling.
    Here a link to a open-source paper that explains the intent of the process.
    Residual Stress from Cold Expansion of Fastener Holes: Measurement, Eigenstrain, and Process Finite Element Modeling

    Hope this helps if this is what your question is about. 


    Nihad Ben Salah
    NBS- M&P Consulting

    ASM Handbook 23A