×
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

Effect of heat from weld on fatigue in steel - after the weld has gone

Effect of heat from weld on fatigue in steel - after the weld has gone

Effect of heat from weld on fatigue in steel - after the weld has gone

(OP)
I am looking at fatigue in a UB member that had a plate welded across the flange, but was subsequently taken away.  In accordance with EN 1993-1-9 this would be treated as Detail Category 50 for calculating the fatigue damage with the plate in place.  

However, as the plate has been removed and the welds grinded off there will not be a stress concentration due to the plate (Detail Cat. 50). I assume there would be some reduction in allowable stress in the member due to residual stresses from the localised heat from the welding process.  My questions are:

1. Is this assumption correct?
2. How can any reduction be quantified?

Many thanks,

Chris

RE: Effect of heat from weld on fatigue in steel - after the weld has gone

Depend on what type residual stress you have. If you have more compress stress, it will reduce the stress applied. But if you have high tensile stress on residual stress, it will break even on small stress you applied

RE: Effect of heat from weld on fatigue in steel - after the weld has gone

(OP)
Do you mean it's dependant on the stress in the member when the weld was applied?  Or the type of stress that will be applied in service?

The member is subject to a fully reversible load so each flange will see both compression and tension.  The weld was applied when the frame was unloaded (except for dead weight).

RE: Effect of heat from weld on fatigue in steel - after the weld has gone

What you can do, if not performed previously,  is have a surface NDT (PT or MT) of the previous weld region to ensure you have no surface cracks. Once this is completed, portable hardness testing can be performed to evaluate the tensile strength of the remnant heat affected zone in the flange base material and decide on an appropriate knock down factor, if any.

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