Contact US

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!

*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

Chemistry change to unassigned metal

Chemistry change to unassigned metal

Chemistry change to unassigned metal

I already know the answer to this but I have to ask anyways.

I have a procedure for an unassigned metal (4130) with Mn .40 to .60 & Mo .15 to .25. If my supplier provides material with Mn .60 to .80 and Mo .22 to .35 do I have to requalify the procedure?

RE: Chemistry change to unassigned metal

This is an issue of debate in some welding circles.  The applicable section of the code is QW-424.1, which states that the unassigned base metal shall be identified "by specification type and grade, or by chemical analysis and mechanical properties."  If an  base metal is defined by chemical analysis and mechanical properties, the code does not say who is defining these.  Some people will not recognize definitions that are not an industry standard, while others say it is up to the writer of the PQR/WPS, (and acceptance of the customer if required).  I have thought about sending an inquiry in on this subject, but haven't yet.  I am also interested to know what others think on this subject.

RE: Chemistry change to unassigned metal

Okay, I guess I didn't know the answer, maybe there is a possible out.

But, if there are no limits defined for the chemical analysis, one could conceivably design the weld procedure with chemical limits so broad as to encompass every known material. Or, is the intent to be able to define an unknown material by analysis and therefore be able to generate a WPS and PQR good for only that specific heat lot.

RE: Chemistry change to unassigned metal

As heard from a ASME Section IX committe member, Section IX is intended to be used with sound engineering judgment.  Obviously, as you know the incoperation of every known metal would be irresponsible and dangerous.  On the other hand, a PQR/WPS that would only be good for one heat of material would be rather restrictive.  What I try to do is find relavent industry standards and see how a material not listed in Section IX is handled by other codes, such as D1.1, ASTM A488, MIL-STD-248, or other ones relavent to your industry.  Just remember that Section IX is based on leak before break train of mind, so many materials that could be grouped together for qualification are not included because they aren't suitable for pressure vessels, (or piping for S No.s)

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! Already a Member? Login


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