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

Weld Cracks on SS to CS Wels

Weld Cracks on SS to CS Wels

Weld Cracks on SS to CS Wels

Dear All,

I am facing an issue on the propagation of cracks on a dissimilar metal weld. The cracks happened in three different scenarios
There is element holder bearing MOC as SS304 which was welded to SA516Gr70N shell. Due to code requirements the vessel was subjected to PWHT.
There was a crack propagation in the weld and the crack was noticed in the following conditions
1) Crack in element holder to shell weld after PWHT.
2) Crack in element holder to shell weld after Hydrotest

I would like to know the reason of this crack development and how to arrest the same.

Kunal Duggal

RE: Weld Cracks on SS to CS Wels

More than likely it was the difference in the coefficient of thermal expansion between the two materials that caused the weld cracking.

The devil is in the details; she also wears prada.

RE: Weld Cracks on SS to CS Wels

Call in an expert to perform a root cause failure analysis. These questions are not answered by crowdsourcing.

"Everyone is entitled to their own opinions, but they are not entitled to their own facts."

RE: Weld Cracks on SS to CS Wels

^ I agree.

You have too many variables that might cause this, that are very relevant:
Joint type, thickness, filler metal, process, interpass, preheat, PWHT (1650 for 2 hrs?)

Did you UT/RT/LPI prior to any treatments or confirm the weld was good prior? The suggestion of differential thermal expansion is a good one, what do the calcs say? Is it restraining? Maybe you are better off to butter, then attach.

RE: Weld Cracks on SS to CS Wels

Your reason for crack development was the MBA who allowed the welding of 304SS valves onto the Carbon steel shell ....

You would have no problems with this type of joint if it were a flanged joint between the Carbon steel and SS...

Sr. Process Engineer

RE: Weld Cracks on SS to CS Wels

Whereas Code (ASME VIII?) required PWHT (1100F min) of the shell due to SA-516-70 thickness, the dissimilar attachment weld may not be subject to Code PWWHT requirements. Regardless the filler parameters discussed by meltedEng have not been identified so how do you expect an answer to your question?

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


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

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