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


Accounting for HAZ in 6061-T6 Pipe

Accounting for HAZ in 6061-T6 Pipe

Accounting for HAZ in 6061-T6 Pipe

In CAESAR II, how do you account for the heat affected zones (HAZ) when welding 6061-T6 aluminum pipe together?

RE: Accounting for HAZ in 6061-T6 Pipe

Im not a CII user (we use AUtoPIPE), but Im pretty sure such effects are not accounted for in pipe stress analysis but rather in your WPS/PQR, and welding inspection plan (ITP).
Can you elaborate on the background of your question? Why did you think it would have influence in pipe stress analysis?

RE: Accounting for HAZ in 6061-T6 Pipe

The 6000 series aluminum alloys are heat-treatable to increase their strength. 6061-T6 is one such alloy that has had it's strength increased by heat treating. When it is welded it looses strength in the HAZ. The Aluminum Association specifies this to be 1" either side of the centerline of the weld. According to Aluminum Association Design Manual, the minimum ultimate strength for 6061-T6 is 38 ksi. When welded it is 24 ksi. The minimum yield strength is 35 ksi, and 15 ksi when welded. B31.3 has similar numbers.

I suppose this could be a code question because I couldn't find anything specific about this in B31.3 other than Table A-1 (Basic Allowable Stresses) does acknowledge this difference in properties. You could take the conservative route and use the welded properties for the entire length of pipe. I just assumed (there I go again), that there would be some way to differentiate between stresses in welded and unwelded portions of pipe.

Just to be clear, I'm talking about circumferential welds where pipes are joined together (or pipe to elbow or whatever). Aluminum pipe is extruded so it doesn't have a longitudinal weld.

RE: Accounting for HAZ in 6061-T6 Pipe

dozer, never thought of it that way, though we normally dont use aluminum piping. However, Im pretty sure 'strength losses' are accounted for in the applicable ASTM A or B specification, and as such, are accounted for in the vlaues of B31.3. To be honest, Im just guessing based on my experience with the B31.3 code; aluminum isnt the only material in B31.3 for which material properties are affected by heat treatment, so Im pretty sure the Coide has some way to deal with this. Hopefully others can help you better.

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!


Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close