SA194 Gr 7L

[roca]

Our supplier is trying to use SA194 Gr 7L nuts - we have specified SA194 Gr 2H.

Has anyone any experience with Gr.7L...?

How does it compare to Gr.2H?

 

[unclesyd]

Grade L7, ASTM A194, Latest Revision New stamping as per ASTM is 7L. Heat-treated chrome-molybdenum steel nuts suitable for extreme temperature and pressure conditions. Suitable for sub-zero service conditions and have minimum Charpy impact values of ASTM spec. A320 Grade 7 down to -150°F.

Grade L7, ASTM A320 Intended for low temperature service down to minus 150° and has a minimum Charpy impact value of 20 ft lb at this temperature (-150° to 1100°F).

Strength wise they are equivalent as to the torque values and clamp load.

In my discussions with a fastener supplier he stated that he was supplying a lot of L7 nuts to people that used to specify SA194 Grade 4 nuts. He also stated that he is supply the L7's and L7M's to people that normally bought 2H and 2HM nuts.

One question is why can't your supplier supply the 2H nuts? There is no shortage of 2H nuts, even the domestic variety.

 

[vesselfab]

domestic 2h nuts? please furnish mill name and possibly a MTR. We have had no luck finding domestic nuts.

 

[roca]

Not sure why.
The change was picked up by our eagle eyed inspector on the stamping on the nuts themselves.
We are asking the supplier to advise why the change and no notification of the change to us his client.

 

[unclesyd]

vesselfab,

Just talked to Mike at Ameribolt and he stated that he has in stock domestic 5/8" and above and only 1/2" is in short supply at present.

They have a google banner add, Cut Studs, that shows up on ET from time to time.

You can Fax Mike Jones at the following.

http://www.ameribolt.com/page5.html

 

[Bonswa]

What's the service? HF by any chance?

 

[roca]

nothing too spectacular - just sea water on one side and tempered water on the other

 

[nickelkid]

Sea water has its' fair share of challenges.