Bolt Grade confusion 1

[mechmos]

Hi,

We regularly use A320 L7 Bolts in our work for load bearing connections, but am I right in saying that standard 8.8 bolts aren't actually that far off L7 bolts in terms of strength and 10.9 or 12.9 are actually stronger?

Thanks.

 

[desertfox]

Hi mechmos

Look at these sites and you can compare the grades:-

http://www.roymech.co.uk/Useful_Tables/Screws/Screw_loads.htm

http://www.americanfastener.com/technical/grade_markings_steel.asp

Regards

desertfox

 

[TVP]

As the links from desertfox show, the mechanical property requirements for 10.9 and 12.9 fasteners are higher than those for L7. A higher tempering temperature is used during the manufacture of L7 fasteners as compared to 10.9 or 12.9 fasteners.