Looking to purchase ....curious if anyone has any experience/owns such
equipment...aka name brand recommendations?
Got about a thousand-some-odd joints of 304 SS Sch 10 piping butt joints to
do!
respectfully,
Harp..AWS CWI, CWE
Hello,
I used a brand "Dimetrics", and was QC (CWI also) on a similar job
approximately ten years ago with the same material specs that you
quote, although I don't know what diameter/wall thickness you are
using. We ran into problems in that we did our weld procedure quals
during warm weather and then with schedule and city official delays we
ended up fabrication during the cold of winter. Most of the spools
were welded indoors and then moved to a trench for field welding. We
did anticipate pre-heat and interpass so the base material was not a
problem. I had worked 13 years or so as a engineering technician
(welding) at a US Navy Shipyard that was closed down, so I had
background on procedures and orbital and mechanized as well as manual
welding. What was a problem was apparently the Dimetrics machine had
an inherent problem in that the electronics apparently did not perform
well in field conditions (cold). It seems that it was more set for
"shop" fabrication applications. We ended up building a moveable
"shelter" and we had flexible electrical heating pads for pre-heating
pipe to remove the chill and to also keep the weld area dry. We ended
up using the heating pads to keep the machine warm and the weld
defects went away. What was criminal was that others knew about the
problems with the machine and neglected to tell us, they wanted to
make money off of the rental of the machine. Long story short, we
ended up hand welding many of the joints because of the city official
problems.
However, I would recommend "Arc Machines" or AMI equipment as
relatively robust equipment, as since I have been QC on many jobs
since then and we have had quite good sucess with that brand.
If you need any other information my email is:
snipped-for-privacy@yahoo.com
One thing to remember, different pieces of stainless steel often have
dissimilar electron emissivity even from the same heat. This can cause the
welding arc to stray from the centerline if you're thinking of doing an
autogenous circumferential seam weld on these pipes. You're probably in the
thickness range where it looks attractive. There are a couple of
manufacturers that make fittings that have mini sockets to avoid that
difficulty. Similarly, if you're looking at 304 stainless, watch out,
because autogenous welds aren't particularly strong. There's a reason why
one uses 308 stainless to weld 304 to 304. It's too long to go into in this
forum, but it ain't as easy as it looks to make good, safe, reliable,
autogenous stainless to stainless weld joints. I'd recommend going to
Parker Hannafin and seeing if they've got any of those fittings in 308 or
maybe 316.
I like the AMI stuff too. I don't think there's a comparison between
Dimetrics and AMI. I think you'll get better service from AMI too.
J
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