Galvanizing A490 bolts

[mhcampbell]

Can A490 bolts be galvanized without causing hydrogen embrittlement?

 

[CoryPad]

It is possible to galvanize ASTM A 490 bolts without causing delayed fracture due to Hydrogen Embrittlement. However, the risk of Hydrogen Embrittlement is large, especially considering the large quantities of fasteners used and their critical nature. You can learn more on this subject from the Research Council on Structural Connections:

http://www.boltcouncil.org/download/RCSC Specification 6-23-2000.pdf

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.

 

[IFRs]

Your nuts won't work if you galvanize the bolts.

 

[unclesyd]

As stated by CoryPad above A490 Fasteners are not supposed to be HDG but are quite often. I have seen a BOM calling out HDG A490's and the purchase order would be signed by the EOR. The orders are in the neighborhood of 25% for HDG of the A490.
In this part of the country (US Gulf Coast) the call out for A325 HDG is about 60% of the time.

IFRs
There is no problems with the nut fitting and tightening as the all galvanized structural fasteners are supplied supposed to be supplied as a unit, Bolt and Nut. The rub comes when you mix and match. If you do mix and match you are supposed to verify the installation of the fastener again though in reality this is seldom done.