A325 bolt grade for outdoor 450 degree ductwork? 1

[StructureMan44]

Which is a better choice for structural connections for outdoor ductwork that can reach 450 degrees?

1. A325 Type 1 bolt (galvanized finish), F436 washer (galvanized finish), and DH A563 nut

2. A325 Type 3 bolt (plain finish), F436 washer (plain finish), and DH3 A563 nut

 

[CoryPad]

Take a look here:

http://www.galvanizeit.org/hot-dip-galvanizing/how-long-does-hdg-last/in-extreme-temperatures

 

[XL83NL]

degrees of what? C or F?

 

[StructureMan44]

It's degrees F

 

[boo1]

see

http://www.eng-tips.com/viewthread.cfm?qid=279402