downhand vs uphill 2

[sftyvlv]

I have asked the question "downhand vs uphill" progression on root,fill and cap passes,when welding pipe. Why do "pipeliners" run down and process and power piping welders progress uphill, what is the difference? No one seems to be able to help.
Can you please give me an explanation?
Sftyvlv

 

[GregLamberson]

unclesyd

I'll have to beg to differ again. Pipeline work is all I do and I have never been on a project in the US where 80% of the welders bust out. In fact it is uncommon to have a pipeline welder come in for a test and break out, seldom happens.

I've been closer to that percentage in W. Africa when we had to use a certain % of natioanl welders, but these guys had no training.

I'll grant you pipeline welders for the most part are not B31.3 or .1 welders, nor can they really weld much of anything else (broad brush, don't want 798 to take offense) they have a very narrow skill set, but I have to say, in their field, they are good. And in my experience, in the States, I can recall a few projects only where a welder or 2 has busted out, for the most part it just doesn't happen.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[JTMcC]

Cross country pipelines will typically run around 1200+psi.

I've never worked on power piping in the upper range you quote, how common is that? I haven't set foot in a powerhouse for a few years tho.

The new designation for 5P+ in the "pipeliner" line of consumable is 6P+. I have some samples but haven't seen it on the shelf yet. 5P doesn't see as much use these days as it used to but it's still the most user friendly consumable out there on the lower grades of pipe, in my opinion. 5P+/6P+ will be with us well after my grandchildren (yet to be born) are long gone ; )

Anyone interested in "as welded" mechanicals on downhill (or uphill) consumables can order, free, from Lincoln the information. Their "Stick Electrode Product Catalog", C2.10 and their "Pipeliner premium pipe welding consumables" C1.100 give quite a bit of information including charpies. The same is available on their various wires and cut consumables as well.

JTMcC.

http://www.firstratefabricators.com

 

[JTMcC]

798 has taken offense. When pipeline work is slow where do you think all those UA hands go?? To refineries, powerhouses, chemical plants, ect.
798 runs the best welding school in the U.S. (my opinion of course, but right nevertheless) inclucing tig on exotics, uphill stick, flux core/dual shield, the bug, ect.
Pipeline work is the most cyclical of all construction and thousands of 798 hands work turnarounds and new construction several months each year. I don't think I've ever met a pipeliner that hasn't worked powerhouses/refineries. They would have years where the family would starve if they didn't.
Look at a few thousand pipeline films (or talk to those that have)and you'll see that they will typically make B31.3/1 requirements. B31.3/1 are many times used as the RT requirement on cross country line pipe and station work.

JTMcC.

http://www.firstratefabricators.com

 

[JTMcC]

798 has taken offense, I should of put a little smiley face after that ; )

But if you travel to cities with a large amount of refinery work, such as the east bay area, or during the days of nuke construction, or large scale steamer outages you'll find the rv parks and motel parking lots plumb full of 798 rigs.


JTMcC.

http://www.firstratefabricators.com

 

[GregLamberson]

sftyvlv

You have sparked a lively debate, my hats off to you. That's what the forum is about, exchanging ideas and experiences.

JTMcC

My apologies to the 798 gods (I live in Tulsa by the way), but you have to admit, these guys rarely bust out and for production welding you can't beat them.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

http://www.oil-gas-consulting.com

 

[unclesyd]

For the uninitiated 798 is a pipeliners union out of Tulsa Ok.

 

[JTMcC]

GregLamberson says of pipeline welders, "You can't beat them".

I say, "but you really, really want to sometimes ; )"

unclesid, 798 is THE pipeliners union. There isn't another one.


Happy Memorial Day, fly that flag!


JTMcC.

http://www.firstratefabricators.com

 

[deanc]

JTMcC

Nothing I like better then stirring up some welders,its at least twice as fun as poking Engs.

You must be fairly young, cuz if ya was old and crusty you would know to what I refered.

No problem,you are indeed correct in your posts. P5 is just a old phrase for 5P,slang if you like. Kinda like that 1109 rod.

So relax and reread your posts. The crews,for the most part do a great job these days and you are lucky you have the consumables you do.

So next time you test,I will watch for you. Maybe hover over your shoulder and ask you questions. thumbsup2

 

[deanc]

http://www.old-picture.com/united-states-1930s-1940s/Welder-Gas.htm

Just so you don't think I've no experience. Things have changed just a little since I got my withdrawal card.

 

[JTMcC]

deanc I'm happy to be able to provide a bit of entertainment for you.

But P5 is not a slang term for 5P among old timers because old timers remember and used the real P5. As I already mentioned, P5 was the predessor to 5P, a completely different rod, with a white coating.
It was replaced by 5P in the 1960's and was a nice improvement.

JTMcC.

http://www.firstratefabricators.com

 

[JTMcC]

Most people already will know, but traditional uphill with LoHi consumables has been used inside the fence (ie in-plant), and downhill with cellulosic consumables has been used outside the fence (ie cross country,distribution and gathering)
This has evolved over the last few years to where more inside type work is being done downhill/cellulosic. Pumping station construction has for the most part switched over to DH. Ton's of Intel Fab piping is welded DH, to the point that some UA locals have had to run ads reqruiting DH welders.
Like has been said the necessary use of LoHi consumables pretty much means power piping will be UH progression. Tho Lincoln does make a downhill low hydrogen rod.
More inside applications are going to DH bead and hot pass with LoHi fill and cap because the joint requires less filler. Pipe spacing is tighter when runnin the bead DH, leaving less to fill and cap. That, plus the bead/hot pass go in quicker DH.
So the lines today aren't drawn as sharply as in years past.

JTMcC.

http://www.firstratefabricators.com

 

[stanweld]

sftyvlv,
There is no real metallurgical difference in welds made uphill or downhill using the same EXX10 classification electrodes. The only metallurgical reason to weld uphill with EXX10 is somehat superior resistnce to hydrogen cracking in the root and this can be readily compensated for when welding typical pipeline wall thicknesses.

There are a number of reasons to use uphill low hydrogen electrodes and other low hydrogen welding processes. Superior impact toughness is but one. High energy pipe in the process and power industry is often quite thick compared to pipe used for pipelines. The joint restraint and three dimensional cooling of the thicker wall pipe, not to mention hardenable low alloy steel pipe also welded, produce metallurgical structures highly susceptible to hydrogen cracking and hydrogen cracking was not uncommon in thicker welds when made with non-low hydrogen processes. Properly made welds with low hydrogen electrodes also provide superior radiographic quality. Note that slow speed fine grain films (more sensitive) are most often used in the process and power industries while high speed films were predominantly used in pipelining (again productivity being paramount).

 

[JTMcC]

Just as an example, using Lincoln Pipeliner 6P+ (a new designation for 5P+)You will typically see mechanical properties like this: yield strenght in the mid 70,000 range, tensile strength in the mid 80,000's, elongation in the mid 30's, and charpies in the mid 60's @ -20F

Using 8P+ (the new and improved 70+) you'll see these numbers: Yield strength in the low 80,000's, tensile in the high 90,000's, elongation in the upper 20's, and charpies in the upper 70's @ -20F and lower 60's @ -50F.

Diffusable hydrogen in multi pass downhill with these rods will be about what you'd see in a single pass LoHi weld, certainly not the levels achievable with LoHi of course but better than most people expect.

I'd just love to see some info to back the claim made that the rule of thumb is that DH progression is 7 times weaker than UH.

JTMcC.

http://www.firstratefabricators.com

 

[rmw]

JTMcC,

Where did you get your engineering degree?

rmw

 

[JTMcC]

rmw I own a pipe welding outfit and have no engineering degree as I'm sure you are aware.
We work with engineering on a regular basis and employ engineers from time to time. I have of course an abiding interest in that engineering which affects our work.

JTMcC.

http://www.firstratefabricators.com

 

[sbush]

To: JTMcC

Please don't answer rmw. This forum could go on indefinitely, when the "football wars" get started.

And, thanks for sharing your wealth of experience. Sometimes when I'm outside of my field, I can't tell when I'm reading BS or not. Your posts are refreshing and, for me, what this forum should be about: Engineering Tips ("Tips" meaning "from firsthand experience").

S. Bush

http://www.water-eg.com

 

[JTMcC]

sbush,

Got it. I saw it coming, I'm done.

JTMcC.

http://www.firstratefabricators.com

 

[EmilGies]

Not to take this on a different course but I was told that Uphill welding requires more heat input. Any truth to this statement?
Some of the new hybrid short arc methods (STT and RMD) use a vert down root progression. I expect this is for speed but wonder if distortion is something important, perhaps this aids in getting a quick and perhaps cooler pass in there?
Thanks for any input.

 

[stanweld]

Because of the slower travel speeds used in uphill welding, greater heat inputs are normally generated versus downhill.