×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• 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.

# Yielding of welds

## Yielding of welds

(OP)
I completed a calculation package a few weeks ago regarding the modification of some lifting lugs welded to a rigid frame. The weld strength calculated from the ultimate strength of the weld metal (70 ksi min.) is adequate for the load with a >5 FOS, but one of the comments I got back was "what is the weld's FOS on yielding?" The yielding of the joined materials has already been addressed elsewhere in the calcs, so my question is: do welds even yield? and if they do, how do I calculate that condition? I have yet to see it addressed in AISC or ASME BTH. Thanks in advance for your help.

### RE: Yielding of welds

Welds certainly can yield. If you're specifying an E70 filler (70ksi min. tensile) that weld will have a yield strength around 58ksi.

To me this question would only become a problem if you're welding material with a higher yield strength than the filler- but you (should) never be doing that. If the weld itself is stressed beyond yield but below UTS, the base material adjacent to the weld is stressed to the same level, and will already be in the yield zone.

### RE: Yielding of welds

(OP)
If I'm understanding correctly, the stresses in the base metal and weld would only be similar at their interface (leg), but for the fillet weld (which is what I have), the weld stress is calculated across the 45-deg. effective throat. So if I were to try and check against the weld's yield strength, shouldn't I be doing this along that throat and not the leg? I also am not quite clear on why AISC does not require checking the base metal at the leg, but rather across the thickness of the part. I would think that if the leg is less than the part thickness (as usual), this would be the controlling mode.

### RE: Yielding of welds

I'm not used to ASCI but in Europe the beam section is checked against the yield strength and the weldments are checked against the weld throat with the ultimate strength of the base material. You do not consider the properties of the filler metal (they must be better than the base)

### RE: Yielding of welds

With a fillet weld, the leg length is not what's important. The throat depth is the effective part thickness through which any stress is distributed.

The throat thickness can also be deeper than the simple geometric throat of the weld, and possibly thicker than the leg length, parts being joined, or both, if deep penetration fillets are used. See attached image for clarity.

If the thicknesses of the parts being joined and the weld are imagined as tubes, and stress flowing through them is imagined as water, the diameter of the weld 'tube' is the throat depth- NOT the leg length.

Another way to picture this is that if you were to slice the weld through its neutral axis, and then measure the cross section, you would be measuring weld length and throat depth.

Ultimately, it sounds like you already have a weld stress level from previous calculation. If you have this number, compare it to the weld metal yield stress at the specified weld size, and you have a safety factor for weld yielding.

### RE: Yielding of welds

BMart006:

#### 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.

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:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!