×
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

Full-Pen or multi-pass weld

Full-Pen or multi-pass weld

Full-Pen or multi-pass weld

(OP)
Hi All,

I have a simple question that I'd like to get some opinions on. My firm is designing some heavy moment connections for industrial pipe racks that use end plates bolted to column flanges. The connection from the end plate to beam is typically a 5/16" max fillet weld. We have some locations where larger than 5/16" welds are required and start getting into multi-pass sizes. My supervisor is of the opinion that full-pen welds are more cost effective than a multi-pass (say 3/8" max 3-pass) welds. I just wanted to get some general opinions on this matter because to me that does not seem like a cost effective solution. Full-pen requires grinding and special inspection, a multi-pass welds required more weld metal but no inspection or grinding. Intuitively I would think a multi-pass filet would be the way to go but I could be wrong. Opinions?

Thanks,
Brad

RE: Full-Pen or multi-pass weld

Complete joint penetration groove welds only require volumetric examination when specified by the Engineer if AWS D1.1 is the welding code imposed. The only welded connections that have mandatory volumetric examination requirements are connections subject to fatigue and are loaded in tension. You can read the particulars if you check clause 2.19 in D1.1:2010.

Best regards - Al

RE: Full-Pen or multi-pass weld

I suspect that there is confusion on terminology, and that when your supervisor says "Full-pen" weld what he really has in mind is a bevel weld, or bevel-T weld.

Step 1, make sure you are speaking the same language.

Yes, there may be grinding involved. But grinding is generally done by a helper, at helper rates, while welding is done by welders, at welder rates.

RE: Full-Pen or multi-pass weld

Worse case condition - and a 3/8 fillet weld is very difficult to get 100% good welds in 1 pass ...

If you have a root pass and 2 cover passes for a large weld, the chances of screwing up all three welds at the same point is just about 0.

If you have one very difficult weld made with just one pass to fill that much weld metal correctly, the chances of a complete weld with no failures at all is about 0. What is your penalty for failure?

RE: Full-Pen or multi-pass weld

Depending on your design criteria, the allowable unit stress for a complete joint penetration groove weld is the same as the allowable for the base metal. The allowable stress for a fillet weld is .3 times the tensile strength of the filler metal, but it can't exceed some value specified by the design standard for the base metal. In the case of structural steel per AWS D1.1, the limits are 0.4 times the allowable shear and 0.6 times the allowable tensile strength. That keeps the designer from using a high strength filler metal on a lower strength base metal and forcing the failure in the base metal. Ideally, the strengths should match.

In some cases it is simply easier to make the fillet weld bigger than it is to prepare the base metal for a CJP and either use a backing or double sided groove with a back gouge operation to ensure the weld is sound.

Best regards - Al

RE: Full-Pen or multi-pass weld

(OP)
Thanks for all the responses. By full-pen I do in fact mean full-penetration or CJP, I thought those terms were interchangeable. The articles had good info in them too, and I do believe in this particular case the multi-pass fillet is the best option. Thanks again!

Brad

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