×
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

How does heating a weld joint for bending purposes affect the steel quality?

How does heating a weld joint for bending purposes affect the steel quality?

How does heating a weld joint for bending purposes affect the steel quality?

(OP)
The design code is B 31.3. Production uses heat extensively to align the joints and we are talking about 304H steel small size piping (pig tails). It's GTAW welding, so they simply use the rod tip to heat the existing weld and sometimes the joint comes into position without additional force applied, just due to thermal shrinkage but sometimes they also apply some force. Is this a point of concern?

RE: How does heating a weld joint for bending purposes affect the steel quality?

What is the limitation on heat applied? Do you have a procedure, if not, you should develop one.

RE: How does heating a weld joint for bending purposes affect the steel quality?

(OP)
Metengr, it's simply not measured. I guess it would be the same as that of the interpass (177-200 Deg.C) but it's only a guess. Why do you think this might be a concern if there isn't a documented procedure? What are the advisable limitations on this kind of procedure? Below transformation limits?
Thanks for the input

RE: How does heating a weld joint for bending purposes affect the steel quality?

Because having a procedure demonstrates control of the process. In your situation, you mention no temperature limits. Improper application of heat or re-welding to induce local residual stresses can be harmful to the weld joint. Do you perform any NDT after using heat to enhance alignment?

RE: How does heating a weld joint for bending purposes affect the steel quality?

(OP)
I absolutely agree on the point of having more control of the process but it is hard to convince the production guys on this issue unless you present them with real dangers of this activity, because these guys have been doing it all the time and they haven't had any problem (until now). In most cases there is no NDT after heat application... what kind of potential defect might occur?

RE: How does heating a weld joint for bending purposes affect the steel quality?

You may have had product performance problems in the past because they did not show up until after the part was placed into service. I can't tell you how many times I heard the phrase “we have never seen this before". Either way, your organization needs to have some established practice to avoid this type of repeat performance. If a subsurface weld defect were to propagate to the surface after the application of heat or during the application of heat in an uncontrolled manner, wouldn't you want to know this, this is why surface NDT after heat alignment is cheap insurance.

RE: How does heating a weld joint for bending purposes affect the steel quality?

(OP)
Metengr, thanks a lot. I will take your advise

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