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rickbreezy
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    Sat Oct 03, 2009 10:08 pm
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When I learned how to weld pipe I was an apprentice in the pipe and steamfitters local 540(Newport news Va). I couldnt get much info out of the old heads there, they had all the knowledge on lockdown like it was guild secrecy or something. Later I went to community college school on my own, but the instructor was sortof a dumbass.

So my question is, what exactley is a hot pass? When I welded(or mostley grinded) pipe, we used ( assuming the pipe preperation allowed for it) 1/8 6010 for a root, 3/32 6010 to clean out the root, and then 3/32 7018 to fill/cap. The whole time the machine were set on 90 to 110 amps. Was the 3/32 6010 pass the "hot pass"? after that job I switched over to structural welding and havent heard of a hot pass since. So I have always wondered. Anybody got the goods on this method?

-Rick
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Yes, the hot pass is the pass after the root to clean out any slag that may be left in the root pass.
Jim
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the hot pass got the name from 6010 pipe joints where the second pass had to be "hot" enough to burn out any leftover slag from the root.

its kind of a misnomer....for example on tig pipe joints, people still call the second pass the hot pass even though its sometimes run colder than the root.

the one thing you can probably count on is that the therm "hot pass" is always referring to the pass after the root pass...usually on pipe welds

jody
wstt
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    Mon Nov 04, 2013 4:38 pm

jpence38 and admin,
I agree that hot pass is used to clean out any slag that may be left in the root pass but also it is used to perform heat treatment to the root pass especially when the root pass has been performed with E6010 electrode that is a non-low hydrogen welding consumable. Please have a look at this link:
http://www.weldinguide.com/gdanastasiad ... ?f=2&t=434
regards
wstt
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