Hi guys, great forum! I've been a lurker for awhile and this has been a great resource! Now I've got a couple of questions...
I'm trying to develop skill welding pipe and I have a question concerning the tack welds. Should the tack welds penetrate fully to the inside of the pipe or are they just supposed to go far enough in the groove to hold the work together and get burned through with the root pass?
I have been trying to make my tack welds penetrate fully. Then I grind them down even with the bottom of the groove with an 1/8" wheel. The reason I ask, is sometimes when I run the root pass over the tack weld it seems to cool the arc enough that sometimes it leaves a little void right after the end of the tack. Then it heats up and starts penetrating again. If the tack weld didn't penetrate and I don't burn through it, I still end up with a void.
Also when it all comes together and I hear that nice sizzle inside the pipe, I don't always seem to be getting the *keyhole*. Except if I slow down too much or get the rod at too much of an angle. Then it opens up and usually turns into a gopher hole! I'm using light pressure on the electrode inside the groove. Too much and I get stuck.
Do I need more heat, or is it something in my technique or the way I've prepaired the materials?
Here's some data:
4" sched. 40 pipe
30* bevel with 1/16" face and root
1/8" 5P electrode
90 amps, DC reverse
direction of weld: down
position: 5G, 6G
Scott