Hardness of a bolt

Date 04-15-2004 10:15

Good morning,
Here is a chart with 8.8 bolts listed.
Try this...
http://www.rigging.net/Bolts.html
It doesn't give a rockwell hardness for the 8.8, but it says it is quenched and tempered.

Hope this helps,
John Wright

By kam

Date 04-15-2004 12:54

I know everything is listed in SAE specifications. Dont remember which volume....I used to do metallurgical testing on them yrs ago. I would try to find someone with copies of these specs.

kam

By BillC

Date 04-15-2004 14:55

An 8.8 head marking means the minimum tensile strength is 800 MPa and the yield strength is 80 percent of the ultimate.

10.9 means 1000 MPa and yield strength is 90% of ultimate.

Do you see the pattern?

I leave it to you to do a google search for a conversion table to convert the tensile strength to Rockwell C.

Regards,
Bill

By jwright650 (*****)

Date 04-15-2004 18:03

I'm sorry, I didn't look towards the bottom of the chart, it says that 8.8's have a min Rockwell C of 18 and a max Rockwell C of 31. It gives Brinell figures along with others. So, I think it's about the same class of hardness as a US Grade 5 bolt.
John Wright