Plating Steel

Discussion in 'Finishing Techniques' started by Johnny luvs Biplanes, May 17, 2004.

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  1. May 17, 2004 #1

    Johnny luvs Biplanes

    Johnny luvs Biplanes

    Johnny luvs Biplanes

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    Hi all, this is sort of a finishing technique so here goes:
    What plating proccesses can be used on engine studs (into alluminium) for protection/beautifying?
    Also what plating can be done to 4130 steel for the above reasons?
    Can you paint over plated parts safely and successfully?
    I am worried about embrittlement of the parts and also of electrolysis on the studs.
    Any help would be useful, thanks.
    John :)
     
  2. May 17, 2004 #2

    wally

    wally

    wally

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    For what it is worth,

    What I have seen in the airplane industry is usually a cadmium plating on 4130 followed with an epoxy primer and then paint. For repairs and small parts a procedure called brush cad plating is used.

    The embrittlement issue is a concern mainly with the higher heat treated steels such as Landing gear parts made of 4340 or 300M steels. 220ksi to 300ksi. They have to be baked at a certain time and temp after heat treat and plating to prevent the hydrogen embrittlement.

    4130 can be modestly heat treated too but is usually used in the condition "N"- normalized - about 90ksi. Chrome plate shouldn't be a problem. Your plating shop could tell you more.

    When threading parts into aluminum, it is customary to lighty coat the threads with an anti-seze compound. Corrosion is not usually an issue.
     
  3. May 17, 2004 #3

    Midniteoyl

    Midniteoyl

    Midniteoyl

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    I dont know if I would plate the threads of any stud/bolt used in a structual application. You could just chrome, powder coat, or polish the bolt heads.

    For 4130, you could use chrome, cadium, powder coat, or a ceramic coating like Jet Hot.

    This site has a wide selection of 'diy' plating supplies: http://www.caswellplating.com/kits/index.html. Easy to setup and do - And easy on the wallet.

    Jim
     
  4. May 19, 2004 #4

    Johnny luvs Biplanes

    Johnny luvs Biplanes

    Johnny luvs Biplanes

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    Why not plate threads? Bolts and nuts are plated on the threads, surely it's no different?
    The plating kit link is a good one, thanks (they have a UK distributor too).
    Cheers
    John :)
     
  5. May 20, 2004 #5

    StRaNgEdAyS

    StRaNgEdAyS

    StRaNgEdAyS

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    I once had some bolts plated for a car engine I was building. The plating on the threads was not an issue, as the thickness is marginal at best. However, I would advise against plating anything that goes into the oil galleries or crankcase area, as however unlikely in the short term, flaking may occur and little pieces of chrome and/or the base plate it sticks to could get amonst the moving parts and really spoil your day.:whistle:
     
  6. Jan 19, 2006 #6

    wsimpso1

    wsimpso1

    wsimpso1

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    Plating threads with cad is a no brainer, AN hardware is cad plated.

    Likewise hard chrome or electroless neckle is no big deal either.

    The big problem is with traditional bright chrome, which is actually copper, then nickle, then chrome. It requires polishing, sometimes at each step, builds significantly and spends quite a bit of time in the bath. This can allow corrosive attack in the roots of the threads, diffuse copper into the steel threads, and in general compromise the fastener. The smaller the thread cross section, the more this can happen. This is not to say that it will, but the exposure can produce that nasty byproduct. Mask the threaded portion and just plate the machine screw head and the outside of the nut, and you will be ok.

    Mentioned in one of the responses was baking after plating to prevent hydrogen embrittlement. This is very real and must be done when electroplating. There is no penalty to baking too long, because you are just trying to drive off the atomic hydrogen that is trying to diffuse to the grain boundaries and facilitate brittle failure.

    The biggest question is why bother. I know that AN hardware seems expensive, but it is already cad plated, and quite corrosion resistant, and compared to going out and masking and plating other fasteners, it begins to look cheap...

    Billski
     

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