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Arc welding v groove help!!!



ChInO4o9
08-09-2008, 03:44 PM
Hey guys!! I need help on a 5/8 double bevel plates with 3/8 backstrap plate horizontal. I wanna know what the proper weave pattern and how to stack them in there properly before capping!!! Im using 7018 3/32 low high rod.... Thanks posting.php?mode=post&f=14# (http://www.longevity-inc.com/forum/posting.php?mode=post&f=14#)
:mrgreen:

bhardy501
08-10-2008, 09:23 PM
Is this according to school guide lines or something you are doing for practice? I would use 1/8 7018 and lay in stringer or straight passes. If you need to use a weave I would try to keep my weave tight with a very slight pause on each side to penetrate into the corners. A little more info might be helpful.

ChInO4o9
08-11-2008, 09:01 PM
Im in welding school. The only problem I have is stacking my stringers in the horizontal groove before capping. Its like it wouldn't be flush before my cap. Its like my bottom be higher than the top cuz of gravity. When I cap its good except the top stringer. I get a lot under cut cuz its not flush. What weave pattern you recommend or what? Thanks

Gaustin
08-12-2008, 12:51 PM
If you have the basics of getting each bead shpe correct, pay attention to the placement.

See this animation I made. http://weldingdata.com/horizjoint/horizjoint.html

Don't lock yourself into a 3 bead, 4 bead cap etc. Leaving the top edge too underfilled will cause undercut. Also, pracctice tying together stringer beads on a plate with no groove in the horiz position. Pay attentione to where the toes of eacj new bead fall on the previous bead.

May be helpful http://weldingdata.com/beadSequence.htm

Here is a 6G tube test I took for the boilermakers a few years ago. The picture is upside down. This was done with 1/8" 7018.

Again, once y ou have the skill to run a bead consistently, the good looking welds are often result of bead placement. When running a multipass weld in a groove, that very last bead represents the weld the most. The one below is not a "shining" example but is only a typical cap on a 2" XXH pipe coupon. I use 1/8" whenever possible. Less starts and stops, more head etc. 3/32" have their place but not on material that can take the heat.

I have taken quite a few plate tests. NEVER with a 3/32". It is OK. I just haven't done it . 3/16" or 1/4" material is more for 3/32"s.

http://weldingdata.com/pictures/weldcap.JPG

ChInO4o9
08-12-2008, 07:34 PM
Thanks you!!!!!!!!!

bhardy501
08-12-2008, 08:27 PM
One of the problems of undercutting could be you are moving to fast or you have an incorrect rod angle. If you are going straight in with your rod at a 90 degree angle to the work peice you arc could be forcing the weld pool to build on the down side. Try dropping the back end of the rod a few degrees. That would force the arc up a little and fill in the undercut. Try slowing down a little if you are moving to fast it will under cut. Its hard to say exactly what is causing the problem with out watching you weld. Are you using a leading angle on your rod or a trailing angle, or are you going straight in. To much leading angle can push your weld pool ahead to quick not letting it back fill. I like a little trailing angle, I can control my weld pool better that way. I like Gaustins video and advice on leaving the down side a little deeper than the top side.