Aluminium alloy assembly with carbon steel fasteners

Question

Aluminium alloy assembly with carbon steel fasteners

PrintScaffold (Mechanical)

(OP)

11 Sep 21 08:54

Hello everyone!
If aluminium alloy assembly is held together with carbon steel fasteners (screws, washers, sometimes nuts as well) in the industrial environment, will there be an issue with contact corrosion? Shall we galvanize steel fasteners? If so, what is the recommended coating? Will zync work? Thanks!

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TugboatEng (Marine/Ocean) · Answer 1 · 2021-09-11 15:17:08

Pop open the hood of your car and have a look at the fasteners that hold your engine together.

There are many inorganic zinc coatings today that prevent galling with aluminum and have reasonable corrosion resistance.

EdStainless (Materials) · Answer 2 · 2021-09-11 16:42:25

Assuming that this isn't in a wet environment you should have no issues using coated steel fasteners.
Glav, Zn+Al, IOZ will all work fine.
Preventing galling and sticking is the first order.
And remember to use nice thick strong washers so that you don't crush into the Al.

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P.E. Metallurgy, consulting work welcomed

blacksmith37 (Materials) · Answer 3 · 2021-09-11 20:00:14

Steel screws have a fair chance of galling when self tapping into aluminum.

IDreamChaserI (Materials) · Answer 4 · 2021-09-13 00:51:44

RE: Aluminium alloy assembly with carbon steel fasteners

IDreamChaserI (Materials) 13 Sep 21 00:51

May be could consider machinable glass ceramic?

PrintScaffold (Mechanical) · Answer 5 · 2021-09-13 18:05:47

RE: Aluminium alloy assembly with carbon steel fasteners

PrintScaffold (Mechanical)

(OP)

13 Sep 21 18:05

Thanks everyone for their input!

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**guest0821** (visitor) · Answer 6 · 2021-09-14 19:25:03

I've experienced totally seized steel bolts in aluminum engines. If space permits I pound it on the head with the biggest hammer available; this has given some success.

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Aluminium alloy assembly with carbon steel fasteners