Re: TIG welding of Large dia SS Pipe

What makes the areas hard to purge?
Have you tried the hypodermic needle trick? On Sunday, July 1, 2001, at 03:44 AM, Tin Soe Thein wrote:

> We are using KOBELCO TGX-308L or TGX-316L filler rod for large diameter
> SS
> pipe where difficult to purge. This fillers are flux cored filler rod
> which
> produce slag to protect reverse side bead from oxidation by the
> atmosphere.
>
> Don't forget, slags will be inside the pipe.
>
> Tin Soe Thein
>
>
> ----- Original Message -----
> From: "Paul Bowers" <pbowers@pipingdesign.com>
> To: <PipingDesign@yahoogroups.com>
> Sent: Thursday, June 28, 2001 7:19 PM
> Subject: Re: [PipingDesign] TIG welding of Large dia SS Pipe
>
>
> > For thin-wall (Sch. 10 and under) cryogenic service, we used to
> > reinforce the piping at intervals inside the cold boxes to help
> > correct out-of-roundness.
> >
> > Slip-ons were always used, since greater mass during cooldown was
> > a startup heat-retaining problem.
> >
> > This probably doesn't help for the specific problem and it's a bit
> > more complicated than that, but at least it's a reference point.
> >
> > Paul
> >
> >
> >
> > > this is fine Geoff. But please note the the lenght of those
> > bladder are
> > > quite long for large bore piping (SOCAP from Italy). Beside u
> > stiil have to
> > > find a way to insert the hose near the weld area pass the
> > ballon.
> > >
> > > We've acutally tried quite a number of technique. We built a
> > cage, inserted
> > > the welder to perfrom back weld , then from the outside we
> > ground/clean the
> > > root then do the hot pass. If we're really in hurry, we put two
> > welders -
> > > one inside and one from the outside. Weld are perform almost
> > simultaneouely
> > > with the welders from the inside slightly ahead.
> > > The 3rd method is to install the hat or dam fabricated out of
> > carboard and
> > > fitted from the inside around te weld joint. we then tape a
> > masking on the
> > > outside and perform the weld. The last is the use of dissolving
> > paper to
> > > create a dam around the pipe.
> > > The first 2 tecnique actually eliminated the need for backing
> > gas.- its the
> > > oxiadation that you worry about with this type of welding.
> >
> >
> >
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[Non-text portions of this message have been removed] Received on Fri Jul 06 01:34:00 2001