×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Differencies between ASTM A320 L7M and ASTM A320 L7

Differencies between ASTM A320 L7M and ASTM A320 L7

Differencies between ASTM A320 L7M and ASTM A320 L7

(OP)
hi, to all.

I'm interested to know if there are differencies between ASTM A320-L7M and L7.I'm selecting bolts and nuts for Low Temp Valves. About their differencies i have found that L7 are mechanically better than L7M and also that L7M are in accordance to NACE requiremnts. Tis means that L7M can be considered NACE?

I have also noted, for example that comapny as Shell uses indistinctly for sour and not sour always ASTM A 320 L7M.

Thanks for all.

Best Regards Vincenzo

 

RE: Differencies between ASTM A320 L7M and ASTM A320 L7

Both classes use the same chemical composition (C 0.4 - Cr 1.0 - Mo 0.25).  The difference is that L7M is required to be tempered at 620 [°]C minimum, which reduces the mechanical properties, but improves toughness and resistance to embrittlement.  L7M can meet NACE requirements for use in sour service.

RE: Differencies between ASTM A320 L7M and ASTM A320 L7

(OP)
Hi Cory,

Thanks for your help/explanation i want to attach a good document that i have found on web about Nace Stud Bolts Classes and API requirements in wich it is clear when the L7M or 7M is necessary instead L7 or 7 grades.

Nace after 1997 had eliminated the classes and now speaks only about h2s presence or not.
For these reasons the stud and bolt Classes 1 and 2 means the use of L7M and 7M grades while for the Classes 3 and 4 it is not necessary the use of a NACE material (h2s not present)so are suitables 7M and 7 grades rispectively for ASTM A320 and ASTM A194.

Thaks for all i hope that the attached document is usefull not only for me but to the other peopole.

With my best regards Vincenzo Saviello.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources