Currently work on a bio-fuel facility doing stainless we have some really out of wack pipe which is of course not uncommon but these are all x-ray joints wondering which would be the best way to deal with the hi/low issues. We are considering consumable inserts, how beneficial would this be and I assume argon backing would still be required, any thoughts on this would be greatly appreciated. Have had some fair to good results with the open root but because of the hi/low have back welded alot of joints where ever possible. Which has been acceptable for now, but will be moving on to alot of joints where this will not be possible. the hi/low in some cases is quit extreme. To top it off the pipe is extremely contaminated and on other sites I have worked on it would have been rejected, so we battle on.
Consumable inserts are NOT a cure for hi/low. Quite the opposite. And yes you would need a purge. You have essentially two choices, dogs or clamps.
What size and schedule pipe are you working with?
You mention contamination but are not having issues with porosity or such?
js55 is correct that inserts will not solve your hi-lo issues.
Be sure to soft tape the ODs of the mating pipes. Assuming the ODs of each pipe is the same, use a Dearman type push dog clamp or simple "hickey" bars to bring the joint into allignment.
QCRobert
exactly what Robert said i did a ton of sch 5 /10 stainless at anheisheur busch the fittings
are usually pretty good the pipe is egg shaped . you need to work the clamp around the pipe
skin tack as necessary it takes alot of time and patientce. makesure you geta stainless dearman or you'll contaminate
the stainless joe
Get a SS Dearman clamp and some extra feet, or get good @ working the fit out with dogs. As for the contamination, take your time w/ the end preps, wipe with isopropyl alcohol and run purge dams.
Don't forget spacing wedges and s.s "push-pull" dogs. Some type of diffuser on the end of the purge hose will help, I like to use an old large gas lens.
Id be real careful using pulldogs on sch 10 pipe you might end up tearing the pipe. Invest in the dearman.
Is your contamination on the inside inside of the root. Use an oxygen sensor to
make sure you have adequate backing gas inside the pipe. be sure that there
is no moisture from humidity or rain inside pipe. make sure your wire wheels and brushes
have only been used on stainless. i've seen alot of people try and use the same brush omn a cs
weld than a day later use the same brush on ss it doesn't talke much to contaminate
I only allow rain inside the pipe when I want to control ferrite content through a quench.
If you cap the ends off after rain gets in and weld it out 1G that works best
we are dealing with the contamination our pipe is SCH10 with a water jacket welded on the outside inner pipe sticks out 10 inchs from each end and is deformed from welding. I am looking to rent or purchase the dearman clamps. all wheels and brushes are dedicated to stainless. Thanks all for your thoughts and advice.
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