The same information is in the "Lincoln Procedure Handbook of Arc Welding",
if you happen to have it. That book contains a huge amount of informatuion
and is only around $30. The "Welding Pressure Pipelines & Piping Systems" is
free from Lincoln.
But like I said, anyone that works in the pipeline field will be aware of
It's odd that you told us that "cellulosics don't match the strength of
modern pipeline steels", then you told us you were speaking from "knowledge
and experience", and then you told us you've never worked in commercial
welding conditions. I do feed the kids and pay the bills as a pipe welder, I
have for over 20 years and I have a pretty large amount of pipeline
experience, I know what consumables are in use, today, on "modern pipeline
steels" and at what polarity. This is basic info that anyone with a year or
two in the business knows. I've tried to point out some real world facts as
they are in the field, thinking that might be a bit helpfull.
Maybe you're better off if you continue to discuss the topic with people
who've never set foot on a right of way in their life, and have never burned
a can of 6010/7010/8010 in anger, much less pallet loads per job. And
certainly have never set the procedures on a job, or laid eyes on a line
pipe Mill Test Report.
100ksi as-welded deposit is obtainable using 9010, a downhill pipeline rod
for X-80 line pipe. Mid 90's ksi deposit is what you normally end up with
using the most common downhill pipe rod in use today (70+).
There are grades of line pipe that aren't suited to the normal consumables,
but to take that still fairly uncommon example and then say that "celulosics
don't match the strength of modern pipeline steels" is picking an unusual
example from one extreem, and trying to make it apply across the board.
Thousands of miles of pipeline (X-80 and below) are welded with these
consumables (6010, 7010, 8010, 9010) in the U.S. every year.
I apologise for going beyond my experience here. I've read all you
have written with interest.
What I will do is to work hard with the xx10 series of rods. I've had
a lot of discouragement here. Your information from "where it all
happens" makes it clear that I should be a lot more robust about
building these skills.
It is a realistic appraisal that I have recycled hearsay too much. I
have though worked handling 690MPa / 100Ksi structural / pipeline
steels from Dillinger Huette and Japanese steelmakers and studied
weldability issues in a small project where I was sole researcher.
I am able to comment that Lincoln Electric are very helpful and
forthcoming, including directly from their UK base as well.
I have the book "Welding Pressure Pipelines & Piping Systems" as a PDF
and will read and practice its recommendations very carefully.
Here is what it says in the booklet you mentioned - Lincoln's document
"c2420.pdf", "Welding Pressure Pipelines & Piping Systems" (full
credit for this direct quote given)
"Root Pass Welding
In each case listed above, with the proper fit-up, the current with a
5/32'' (4mm) diameter electrode will be in the neighborhood of 130
amps. From this point, the current should be changed according to the
individual welder's skill and needs. In the United States, root pass
welding is usually done with reverse (DC+) polarity. In International
locations straight polarity (DC-) is often used. Negative melts
electrode faster then positive therefore travel speed should be faster
and internal undercut and hollow bead defects are less likely. DC-
(straight) polarity is also advisable for thin wall pipe to prevent
"- Since reverse polarity (DC+) is commonly used by U.S. pipeline
operators for root pass welding, switch to straight polarity (DC-)
when burn through, internal undercut and hollow bead defects
persist. Polarity change is an essential variable in API 1104 code -
requiring a procedure qualification."
Continuing thanks and regards
I'm glad you found that, you'd of never believed me otherwise ; )
I only comment on those parts of the wide and broad welding world that I
have personal experience in, and there is a ton of missinformation out
there. On the internet in general, and usenet in particular, there are
people who hold forth as experts in areas they know nothing of, usually
quoting straight out of the book and that's soooo easy to spot, especially
in my main field as there is a small amount of information in print, so it's
easy to recognize. Also the terminology is very distinct and unusual, making
it even easier to spot people with no real world experience.
So keep in mind that on usenet and the interweb there is no shortage of
people spewing incorrect and just flat out wrong info. It really has to be
seriously filtered to get down to the actual facts.
Hi again JTMcC
You've got me wrong at least a little bit here.
Do put yourself in my position.
I turn my welding machine to DCEP and people come up to me and say "so
you don't want weld penetration then?". Then someone buys a Dynasty
200DX and rings me on his cellphone, highly distressed, at the
equivalent of 50c a minute trying to work out why Miller "make the
machine cheaper by letting it switch the DCEP for stick" from DCEN for
DC TIG when "with the right circuits it would stay on DCEN". Aaaggghhh.
It's dealing with these people - "third parties" to this conversation
between us in the group - that I ask about evidence to show them -
something incontrovertible. Now you point out about the Lincoln book,
I must print it out.
As a scientist, of course I ask - is there data about burn rates,
penetration depth, etc, where someone has set out and done a set of
tests in controlled conditions. It's not that I disbelieve you - it's
in my nature to look for a body of evidence.
I don't want to get onto a slippery slope or thin ice again, but was
talking with some of the Welding and Joining Society folk today,
meeting at the UK branch of Halliburton. They concur with what you
were telling me, saying there is a resurgence of interest in using
cellulosics, of the type you described - higher strength such as 8010
or 9010 - because the controllability of xx10 stick can dominate over
the apparent productivity advantages of wire-feed processes. Now, I'm
going to back away and go practice my welding, because I can't comment
on this area myself...
As a pipeline welder, I have an additional question to ask you:
After the root pass, is it common to grind the weld top bead, before
the hot pass?
I get a very humped top bead, as I understand you expect if you drag
Further question leading from this:
"Feathering" the end of the previous weld run before striking an new
rod - in reality is this frequently done?
I know of using a slitting blade spinning partly through the root gap
to leave a "chisel edge profile" "feathered" edge which the next run
can proceed from with an invisible progression.
Time is money. And so far I would have two angle grinders to hand,
one with a normal grinding disc and one with a slitting disc...
The tack welds are feathered, after that it's pretty uncommon.
I've known new guys that had just broken out that did that type of thing on
tests. A full blown welder won't. When you start at a tack, or restart for a
new rod, you start welding at least 1/2" before the end of the previous run,
then by the time you get to the end of it and start putting in new bead it
will tie in nicely without visible evedence that you started/stopped there.
More commonly you would have a grinder with a wire wheel, and one with a
grinding disc. I keep a few thin wheels in my truck, but they only come out
in unusual circumstances.
Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here.
All logos and trade names are the property of their respective owners.