"T" joint weld bead size reccomendation

The throats of the two fillet welds should equal the thickness of the material. For half inch plate two fillets each with a throat of 1/4 should be sufficient. General rule of thumb is 2/3 leg length of each fillet. 3/4 is plenty. This is assuming that there is no penetration into the corner of the joint so generally there is lots of margin here.. Randy

Is the assumption of no pnetration into the corner of the joint on a fillet weld standard? I have noticed a similar thing in a lot of my welds and thought that I must be doing something wrong.

Thanks, Bob

Generaly when you are welding to a code there is no asssumption that you are penetrating deeper than your bevel preparation. If the designer wants deeper penetration he calls for deeper PREPARATION. The alternaive is to "prove" the depth of fusion into the plate by running a qualification test where samples are welded using specific settings that will be repeated on the work piece. If they do this for fancy code work then it tells you that just cranking up the heat and guessing how deep you sank into the parent metal is a gamble. Randy

Randy, when you say "no penetration into the corner," does that imply that there may be a bit of a triangular gap between the bead metal and the corner? Or does that mean that the bead is fully welded up to the corner, but not any further?

I don't know if I'm explaining my question very well -- my question may be as muddled as some of my welding is!

Andy

Okay, thanks. I *thought* surely it was supposed to go right up to the corner, but got a little confused with the language. I know we've discussed this on this newsgroup before, but I think the concept of penetration is one that confuses us newbies more than just about any other!

Andy