when putting cap on 3" or 6" pipe in the 2G position, can you start the stringers from the top of the pipe? Is that considered correct? I could have sworn i was taught to weld a stringer bead cap from the bottom up. One of the welders at my job told me to start at the top. I wasn't sure if he was right, but I tried it anyway, and it did look a good bit better. What about the 6G? Thank you for your help!
Most Welding Procedure Specifications (WPS) require vertical welding to be placed while traveling up-hill. This is due to the fact that an up-hill weld is stronger than down-hill and is less likely to trap slag beneath. The only down-hill welded pipe joints that I am familiar with is when using all 6010 stick (SMAW) electrodes and that is only in special cases. You need to find out from your Foreman or QC Inspector what the requirements are in the WPS that governs the welds you are making. Get them to explain all of the WPS requirements to see if you are doing the job like it is supposed to be done.
Tim
You can weld downhill on certain projects using 6010, 7010, 8010's or other rods that fall in that field. This used mainly on pipeline & compressor stations, there may be a few plants still using a downhill procedure, but it sounds like someone might be testing your lack of experience. Talk with the foreman or better yet talk to the QC on site if you have one.
my understanding of down hill would be welding a pipe in the 5G position, starting the arc at the top and traveling towards the bottom. What I meant in my original post is welding on a 2G position ( the pipe running from the floor to the ceiling "verticle") I believe I was taught to apply root pass, then a stringer bead on the bottom half of the joint, then a stringer bead on the top half of the joint filling the joint. Then put the first cap stringer half on the bottom pipe, half on the 1st filler bead. then work my way up. Is that the correct way of doing it, or can that first cap stringer bead be half on the top pipe and half on the 2nd fill stringer bead? Perhaps you knew exactly what I was talking about, and already answered my question... is my understanding of down hill out of wack? Am I making any sence here? :)
Pardon me...
For some reason I was thinking of the pipe itself in the 2G (horizontal) position.
I doubt the WPS states which cap bead, top or bottom, should be placed first.
Tim
I have almost always placed the beads from the bottom up however if your machine is set properly, there is no need to stack beads from bottom to top. In my opinion, you can run more heat and carry a bigger puddle with that extra "shelf" to build from.
Hava a good day
G Austin
To me it is easier to stack em' up, like Gerald said, "on a shelf". I think you will fill the joint faster, as a bonus.
JOhn Wright
I have done this on small pipe. The reason is heat input. You can put the top pass in no matter what position the pipe is in (2,5,6), and the heat will not affect the bottom pass as much as the bottom pass would affect the top passs. I admit in the 2G position it is not necessary very often, but in the 5 or 6G, it helps to put the top half in first.
Mike Sherman
Forum
