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Up Topic Welding Industry / General Welding Discussion / Squaring flanges?
- - By Metarinka (****) Date 09-05-2008 19:27
Hello
I've got 3" 310 stainless pipe to a flange about 1" thick the problem being the ID of the flange leaves a noticable gap, not enough to effect weldability but enoguh to cuase issues with fit up.
We're having a hassle keeping these square and concentric, I'm not much of a pipe welder so my knowledge of squaring pipe is limited.
Any tips or techniques on how the big boys do it?

we're thinking of machining up spacers (time and money) or building a fixture (more time and more money, but I'm sure there's other ways or simple solutions
Parent - - By Shane Feder (****) Date 09-05-2008 20:19
Metarinka,
Set your pipe up on adjustable pipe stands.
Take 4 s/s electrodes and hammer them on the ends slightly till the ends resemble small wedges.
Push them into the gap at your 4 compass points (2 from one side , 2 from the other)
Have the flange overhanging the end of the pipe by approx 1/4"
Place a small tack at 12 o'clock (on the outside)
Put the level on your pipe and raise/lower to level
Put the level on the flange face and level
Once level place a small tack at 6 o'clock (again on the outside)
Rotate pipe 90 degrees so tacks are at 3 o'clock and 9 o'clock
Reconfirm pipe is level
Place level on flange face and tap with rubber or wood mallet to get level
Small tacks at 12 o'clock and 6 o'clock (again on the outside)
Weld the inside of the flange (peferably in the flat position if the spool is short enough)
Grind off the 4 tacks on the outside
Weld the outside of the flange (again in the flat position if possible)
Hope that helps,
Regards,
Shane
Parent - - By TRC (***) Date 09-06-2008 13:56
And in addition to the excellent job Shane discribed, when welding the back side and your at the last 1/8" of weld you may want to stop welding for 10 or 20 seconds to allow things to cool just a bit. SOMETIMES the gas in the annular space between the pipe and the flange is expanding and may cause a blow out during tie-in. 
Parent - - By scrappywelds (***) Date 09-06-2008 15:49
they call it squareing for a reason use a framing square and a tape measuer LEVELS CAN LIE if you dont read the bubble the same way.not to mention it doesn't matter if the pipe not level. Don't forget to quarter out the fisrt inside and outside weld pass atleast.
Parent - By Johnyutah (**) Date 09-06-2008 16:38
I agree with scrappy a framing square works every time tack top and bottom move the square 90 degrees and do it again quatering out will save a lot of greif as well. I have had fitters use the little levels on the two hole pins before talk about a mess.
Parent - By dasimonds (**) Date 09-21-2008 21:58
Hey Metarinka,
  Seems to me if you know the difference between the ID of the flange and the OD of the pipe, it should be easy to figure out what you should have for a gap all the way around. By cocking the flange(letting the flange hang on the pipe, then pushing the bottom of the flange towards the pipe), your ready for your first tack.
You'll probably need both a level and squares. A square off the side of the pipe and a straight edge across the face of the flange works well for me. You may need to two-hole the flanges. Depends.
Are you working with a fitter?
Whats the application?
I don't think I'd worry too much about a concentric fit-up. If it were really all that critical, they'd probably be using weldneck flanges. If it were less critical, they'd be using rolled angle rings and backing flanges.
Hole this helps,
Dale Simonds
Parent - By 522029 (***) Date 09-22-2008 00:34
A "flange square tool" from Curvo-Mark (along with the square) makes this a very simple job.

Griff

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Up Topic Welding Industry / General Welding Discussion / Squaring flanges?

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