Low Temperature Bolting Specs

[NewfieNomad]

Our client spec calls for ASTM A320 Grade L7 Bolts for Low temperature service. We can readily purchase BS3692 Grade 8.8 Bolts.
Information on UTS, and YS is readily available but the temperature ratings are not.
Anyone out there have the temp ratings or any other significant differences between these two bolt grades? Thanks

 

[gr2vessels]

Newfie,
The best answer you can get is coming from your supplier, who would sell you the BS3692 bolts;- he is suppose the send you the material certificate and you are not suppose to accept the bolts without certification. On the certificate should be stated the impact properties of those bolts, including the test temperature and the impact values. If there is no certificate or no impact test on the certificate, the BS bolts are not equivalent to the L7 bolts. Give a ring to your supplier.
cheers,
gr2vessels

 

[SJones]

What does the client think of your intended substitution?

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04

 

[NewfieNomad]

Hi there.
I haven't proposed it to the client yet as I cannot find the temperature rating for the Gr 8.8 Bolts.
The A320 L7's are Charpy tested to -195*F... I'd be happy with a -50*F rating , but still no luck on the temperature range for the 8.8's...

 

[leftyeng]

I have a similar question regarding ASTM A320M L7 low-temp structural bolts vs. ASTM A325M Type 3 weathering bolts. Curently our spec lists the A320s, but they are more expensive, harder to get and have longer lead times than the A325 Type 3s. Both types have similar material properties and the substitution was vendor suggested. The client would like to have more information on this substitution. Does anyone have any experience substituting weathering bolts for low-temp bolts? (Application is structural with ambient temperatures down to -45C) Are there any papers comparing the performance of the two?

Thanks in advance,
leftyeng

 

[SJones]

BS 3692 does not require impact testing and is intended for the temperature range 50 (sic) to 300 deg C. Perhaps the 50 is a typo and they meant -50.

Steve Jones
Materials & Corrosion Engineer

http://www.linkedin.com/pub/8/83b/b04