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Up Topic Welding Industry / General Welding Discussion / Maintaining preheat temps
- - By MStevens (*) Date 10-30-2014 15:07
We are trying to maintain a preheat temperature thought a completed weld on 42" X70 pipe. Our requirement is 175 F, we heat the pipe to 220, but lose 80 degrees in under 10 minutes. Does anyone have a trick to maintain the temperature throughout the weld? We have insulated pads wrapped around the pipe 10" from the weld on each side.
Parent - - By SCOTTN (***) Date 10-30-2014 15:23
Matthew,

A couple questions immediately come to mind....

What code are you working with?

What is the material grade?

What is the material thickness?

What is the welding process?
Parent - - By MStevens (*) Date 10-30-2014 15:35
X70 Schedule 80 42" we are using tig to weld the root and hot pass, then fill and cap with 7018. We are following code B31.8
Parent - By jarsanb (***) Date 10-30-2014 17:01
Now that is a pretty conservative welding procedure. PHMSA would be smiling for sure. Without getting into personal opinions on how this could be welded differently to help with this issue, you could look into induction heating - by far your most effective option. The cost of such, however, may prove to be an unattractive alternative. Multiple welders on opposite sides of the joint may help, having someone run torches on the I.D. while measuring temps would work if you have access internally.
Parent - - By S J (**) Date 10-30-2014 19:38 Edited 10-30-2014 19:44
What do the verbatim words in the ASME B31 code say regarding inter-pass temperature control?

Is 220F really necessary between weld passes, or is 220F only used to drive off moisture before the initial welding proceeds?

A clue might be found by using one of the carbon equivalent (CE) formulas which provide a rough estimate of the hardenability of common carbon steels.

Also, 220F is unlikely to provide anything more than a moisture chasing function from a metallurgical standpoint.

Typically inter pass temperature control is not employed until higher strength materials are utilized - say 500F for a 100,000 tensile range material.

But, I will not question your desire for proper code conformance if the temperature requirement is clearly stated, and approved deviations are unavailable.

How is the pipe being welded?  Is the one welder responsible for all tasks, or is a helper available?  Some projects employ two man teams - which might allow for a helper.

Sorry, but I have no practical experience based advice to offer relative to "induction heating" of pipe - it might pose a real challenge in the field.  I have witnessed induction heating methods used in manufacturing for braze joints on small components - with thinner cross sections.
Parent - - By jarsanb (***) Date 10-30-2014 20:16
From the B31.8 reference I'll have to assume some type of transmission application, maybe not. But if it is here are a couple references. His concerns about preheat are fair. I've also included a link for induction equipment used for this purpose.

http://www.millerwelds.com/products/induction_heating/index.php
http://primis.phmsa.dot.gov/construction/docs/ConstructionIssues.pdf
Parent - - By Superflux (****) Date 10-30-2014 21:37
I have to ask:
Are you dealing with coated pipe and and the resultant gooeyness of the adhesive when heat is applied? Welders whining because their new Duck Dynasty camo shirt is getting all tarred up?
1) What is the Maximum interpass temp allowed, and if above the 220°F stated I would suggest bringing the welding zone up to it within reason.
2) How far back are you able to carry the preheat? How big an area are your craftsmen able to cover with the blankets? Area and total mass are going to be your friend.
3) Can you or have you been able to cut off all drafts through the pipe.
4) What configuration of assembly are we dealing with here?
If you were say just double jointing 20' pieces, and double dam could made that was approximately 2 or 3 feet between them, placed on the end of a 20' long rod or heavy wire and shoved into the pipe. A dead air space is one of the best insulators.

That's about all I can think of at the moment that has worked for me in the past.
Parent - - By Cumminsguy71 (*****) Date 10-31-2014 09:22
Could use the hair dryer from the movie SpaceBalls.

Sounds like a tough one here. Can't use a weed burner, guy standing there welding.

Torpedo heater in the end of the pipe? If short enough but that's just a crazy idea, not even sure if it would work with any sort of length.

Heating blankets? Industrial size? Depending on size of pipe couldn't a guy be opposite the welder keeping the heat on but off of the welder? Not sure what size pipe you're working with though.
Parent - By Tyrone (***) Date 11-03-2014 11:49
Hahaha, I just watched Spaceballs with my little guy (9 yr old son - haha), thinking he would love it because he's a Star Wars fan.
Arrrghhh!  I can't believe I thought this movie funny.  I need to stop watching old movies and just keep the fond memories.  At least we both enjoyed Raiders of the Lost Ark.
Tyrone
Parent - - By MStevens (*) Date 10-31-2014 17:57
Every welder has a helper. There are 2 welders and 2 helpers on each joint. The customer is requiring the preheat according to their procedures and will not allow deviation.. Safety will not allow us to heat with a torch while welders are welding.
Parent - By jarsanb (***) Date 10-31-2014 18:12
Here is an example of preheating on the I.D. You can preheat, have welder weld, monitor temps, if temps fall near low range stop welding and reheat. The internal heating is shown around 3:13 of video time. This is not the company I work for though they do get some projects from us. Actually the one in the video is one of our projects. With the processes used, loss of temp was not an issue though max interpass temp was on the 36" 1.000 wall.

http://www.youtube.com/watch?v=mYzLFPg83ds
Parent - By welderbrent (*****) Date 10-31-2014 02:28
Matthew,

Is this a pipeline, that can't be rolled?  Or, are you able to use rollers and rotate as you go? 

Reason, I'm wondering about a "bertha" propane heater on a stand that would bring your temp up just before the welding was done.

Barring the rotation, a helper running the heat over the area prior to welding to keep it up at the joint.

S J, notice the comment was that 175°F was their requirement.  Either by way of code or WPS it doesn't matter, they are bound to that as their approved process.  They are apparently going higher trying to keep the heat above 175°F until they get back around but it isn't working. 

So, having minimized heat loss as much as possible following suggestions of capping the end or plugging in some way (the smaller the area and distance from the joint the better) then there may need to be additional heat applied prior to the welding of that pass.  The main question: HOW?  Without more specifics on your set up that is entirely up to you.

Oh, wish I could remember company names, at Fab Tech a couple of years ago there was an outfit that had a great product for the plugging of pipe for purging and other applications.  Would probably work great...just can't remember who they were.

He Is In Control, Have a Great Day,  Brent
Parent - By blawless Date 11-11-2014 18:44
If nobody advised, try Arcon Welding. 300SH. This is a welder and heater. These are the new Powcon guys. I have several powcons and they are awesome welders. I have a new Arcon Workhorse and it is also awesome. These are tuff well built machines. Used in mining, ship yards/Navy, pipe welding and more. If not built completely mil-spec it's as close as you can get. The arc produced is very similar to the SA200, et.al SA's. IMHO.
- - By 803056 (*****) Date 10-30-2014 23:07
Dive off moisture? Really?

You may be observing the chimney effect if the ends of the pipe are open to the air. If possible, block off the ends of the pipe to prevent a natural draft through the pipe.

Best regards - Al
Parent - - By S J (**) Date 10-30-2014 23:54
Sorry, my bad.

The moisture thought came to mind because of his reference to 220F.

Actually, the "driving moisture" out with preheat questions have been previously discussed at length at this forum.  And, moisture IN the metal is likely fable - with the one possibility being that the moisture observed when preheating with oxy-fuel is related to the products of combustion.  But, moisture might exist in oxide - which should not be present on proper weld preps.

But, what about welding in the morning dew?

Some specs for X70 pipe report 80ksi strength - so temperature controls might be a best practice to optimize results.  And, preheat and temperature controls will reduce the critical cooling rate..so use caution when considering my prior comment. 

Without access to the current version of the proper code, it is best if I bow out from further discussion regarding this concern.
Parent - - By 803056 (*****) Date 10-31-2014 01:50
Great recovery. Nicely done.

Al
Parent - By yojimbo (***) Date 10-31-2014 13:56
Welding 42" .995 wall X 50 pipe in 25 degree weather we would use a propane "spider" weed burner set-up.  Essentially a propane manifold built like the spokes of a wheel, I believe there were 6 weed burners attached at the hub.  The manifold could rotate. 
We'd hook it up to a bottle of propane and light it off wide open, the entire inside wall of the pipe at the root was engulfed.  Two helpers running weed burners on the outside to get it up to 250 degrees and we shut off all the propane and get welding. In those temperatures without blocking off the ends of the pipe [good idea we never thought of] it usually took 20 minutes to get that wall thickness up to temp.
On that size pipe I'm surprised the contractor would elect to use the WPS with a tig root and hot pass.  That's going to make for a long day.
Parent - By 46.00 (****) Date 11-03-2014 22:53
Like!
Parent - - By MStevens (*) Date 10-31-2014 17:58
The ends have been blocked due to high winds in the area.
Parent - - By S J (**) Date 10-31-2014 18:15
Here are some more data points that might be wise to consider:

1.)  B31. What???  Ref. ASME website re. this code - or was their an error in typing?
2.)  Is the process compliance requirement customer or code driven, or both?  Are the technical requirements negotiable?
3.)  What weld shielding technical requirements are imposed by field vs. shop conditions?
4.)  What process limitations are imposed by TIG vs. SMAW?
5.)  What is the weld joint configuration relative to fit-up, and is it an open root or is there a backup ring or bar?

None of these details were included in the original question.

Some older references on the web point to the use of cellular SMAW electrodes to run the root pass for X70, while others suggest the need to restrict hydrogen.  Cellulose electrodes contained hydrogen the last time I checked.

For further inquiry for those who might have an interest:
Regarding B31.whatever:
https://www.asme.org/gsearch.aspx?searchText=b31.*&#page=1,category=

Regarding hydrogen in X70 pipe:
https://www.asme.org/gsearch.aspx?searchText=X70&#page=1,category=

@Whoever…
Points well taken; however, I am not sure they have resolved the debate relative to the need to properly shield (or not) open root pipe joint welds.  Without access to the full details, some of us are just shooting in the dark.

Sorry if I have further confused the issue.

Have a nice weekend.
Parent - - By ssbn727 (*****) Date 10-31-2014 21:20
Hi S J, MStevens,

1.) This is addressed to S J and are suggestions... You need to re-read the OP's (Original Poster's) 2nd post in this thread because MStevens clearly states the pipe construction code they're using: ASME B31.8 - which is the most widely used Code for the design, operation, maintenance, and repair of natural gas distribution and transmission pipelines...

2.) You do have a reason to question the use of a GTAW root pass but, the butt groove joints are normally open root with no backing at all... Good question and yet if it's already been decided by the EOR and no deviation is allowed then that's the way it's gotta be welded...

3.) Carbon steel can be open root GTAW without the need to purge the root of the weld yet with the high wind conditions it would be practical to block any internal uncontrolled air movement with the use of dams or even cardboard cut to size and loosely taped to the inner wall with a wire attached for easy removal...

4.) The root pass is going to take a little bit longer to complete but, if you got the right equipment and a really rugged heavy duty GTAW torch with a large enough W and a power source that can push out the required current to really slap in some steady heat input into the joint without burning the torch out along with a large enough diameter filler rod or if possible a spool of  oh 3/32" diameter wire mounted on a wire feeder system like what Ed Craig is pushing; the Tip TIG welding system, then one can almost keep up with the SMAW downhill speed freaks... Can Tip TIG GTAW run as fast as the Stick downhill process? I couldn't tell you because I haven't heard of it being used on B31.8 projects as of yet, but it would make sense to run a comparison between the two processes with the tip TIG system used with GTAW...

5.) Normally the butt groove joints are open root since it's carbon steel as opposed to a 300 series stainless steel to use as an example mainly because of the chromium content which would result in "sugaring" of the root surface as well as possibly contaminating deeper from the root surface... Therefore requiring a purge with stainless steel GTAW...

All of the other points have certainly been already taken into consideration... And those links you posted do not show anything but the fact that you searched for  both without giving any meaning to each search... So as a suggestion, in the future you may want to check the link to make sure they go to where you want them to go and that the link is still working...

May I also suggest that you read as opposed to just skim through the entire thread each time before posting so that you can give yourself enough time to absorb all of the content within any of the threads posted in this forum, and also understand that the posts in the threads are not always chronologically succeeding each other which at times can also lead to some confusion for some of the newer participants... However, there's no need to apologize because you are going through the learning process of getting to know how this particular forum works and besides, nobody's perfect besides our Lord and Savior...

The OP's original question was: "We are trying to maintain a preheat temperature thought a completed weld on 42" X70 pipe. Our requirement is 175 F, we heat the pipe to 220, but lose 80 degrees in under 10 minutes. Does anyone have a trick to maintain the temperature throughout the weld? We have insulated pads wrapped around the pipe 10" from the weld on each side."

All of the suggestions are helpful, and I think if you already have access to enough propane to use that ingenious spider contraption you should be able to maintain the required pre-heat temp that's required for the job... So I hope I didn't insult you S J because my intent was to get you to refocus more on focusing more on the contents of every post in any given thread in order to better understand what the OP is asking for, and I know if can be confusing with all of the off topic responses one can find in some of the threads for which sometimes I'm guilty of starting... So please don't take what I'm suggesting as anything else other than to help guide you to better understand how to navigate a thread in this forum which at times can be very confusing to anyone who is used to a structured order of posts in a thread... My intent is only to be helpful...:grin:

This is addressed to MStevens... I'm wondering if one of those Miller induction heater systems that SCOTT already mentioned could be available for rental by any one of those equipment suppliers such as Air Gas, and then find out what is the rental fee & what is required to run it in the field, and then compare that to what it would cost to use the spider, and then also consider the amount of time it would take to set up each pre-heat system from joint to joint in order to get a better idea of which of the 2 would be a more efficient and cost effective system to use in the field... Whichever choice you decide, I wish you the best of luck.:grin:

Respectfully,
Henry
Parent - - By Superflux (****) Date 10-31-2014 21:33
Since it is a GTAW root and this grade of pipe, my guess is that it is some nasty gas with hydrogen sulfide or other impure/raw product.
Parent - By ssbn727 (*****) Date 11-01-2014 01:06
I agree... But then again we are only guessing even if it's a good guess with a high probability of being the actual reason for the GTAW root, it's still only a guess and I'm not always comfortable in guessing - then again that's just me.:grin::lol:

Respectfully,
Henry
Parent - By 46.00 (****) Date 11-03-2014 22:55
We call this 'sour service' in the UK!
Parent - - By S J (**) Date 11-03-2014 13:44
Regarding winds, some pipeline contractors use lightweight canvas panels to block the wind.  There are even reports on the web regarding some radical approaches that ostensibly employ enclosed automated welding systems that are moved from joint to joint using a crane on the side road.  I will leave it up to your own judgement whether these reports are a "ruse" or not.

But, the portable canvas panels sound like a practical solution - if in fact the winds are an issue relative to the documented welding reject history.

I'm done for now - my bad if I have taken the discussion further off track.
Parent - - By ssbn727 (*****) Date 11-04-2014 04:08 Edited 11-04-2014 04:12
Hello S J,

Those portable "huts" have been in use for many years now so they are for real and are extremely helpful in cold weather extreme where high winds are prevalent...

http://www.lonestarwelds.com.au/weldinghabitats.htm

In fact, CRC-Evans employs heavy weight external & internal portable orbital welding systems with line-up clamping to weld pipe with the GMAW process... I don't know if these folks tried using the Lincoln "STT" GMAW short circuiting transfer method, Fronius "CMT" or Miller Electric's "RMD" modified short circuit metal arc transfer methods to weld the root pass... And then without switching anything but the method of metal transfer in order to deposit the hot, fill, and cap/cover passes with the same power source that's able to store a variety of separate weld parameters and to instantly switch from one to another in order to completely weld the tie-in joint...

If one desires the use of multiple welding gun/torches deployed with separate power sources, a system can be created to deposit all of the above (Root, hot, fill, and cap/cover passes) almost simultaneously... There are quite a few mechanized systems that can be mated with these types of power sources, and one of the most experienced manufacturers that comes to mind are the Stanley CRC-Evans mechanized pipe welding systems for both onshore and offshore lines... Here's an interesting link:   

http://www.crc-evans.com/our-process

The bottom line is that there are many alternatives available that will increase productivity...  I believe Stanley CRC-Evans offers this equipment to enable the customer to use both modified short circuiting transfer methods as well as spray transfer and can be used with any process such as GMAW, FCAW and probably can even be rigged to automatically GTAW those root passes by adapting the Tip TIG GTAW process variant Ed Craig likes to push:lol:which would substantially increase production compared to manual GTAW and probably with less defective welds if any at all if properly optimized and monitored in real time and practically any of the major welding power sources and welding gun/torches to be mated with their mechanized pipe welding systems... Here is an article published in World Pipelines describing the mechanized welding of tie-ins using the Stanley CRC-Evans Automatic Welding Systems:     http://www.crc-evans.com/sites/www.crc-evans.com/files/documents/WP_W%26F2013_CRC.pdf

Here's an example of how the CRC-Evans system works in general and illustrating the use of the portable welding "huts" as part of the overall onshore line pipe installation system (They also offer an offshore spool type system for use in pipe laying barges and ships):    http://www.crc-evans.com/onshore-process

Here's another article in Pipelines International where Stanley CRC-Evans is mentioned regarding the use of their equipment used in the completion of a 48 inch straight pipeline running through the Corn belt of France... Here's the link below:

http://www.crc-evans.com/sites/www.crc-evans.com/files/documents/PIN_DEC13_Haute_de_France.pdf

http://www.crc-evans.com/onshore-construction

Here's a virtual video depicting how the CRC-Evans internal/external onshore double jointing pipe welding system works:

http://www.crc-evans.com/equipment/land-based-double-jointing

Here's a video of the P-625 external welding machine from CRC Evans:    http://vimeo.com/100120415

Their M-300C:    http://www.crc-evans.com/equipment/welding-equipment/m300

Their M-400:    http://www.crc-evans.com/equipment/welding-machines/m-400

Their Internal Welding Machine:    http://www.crc-evans.com/equipment/welding-equipment/manual-internal-welding

Their V Root is an intelligent internal inspection system:    http://www.crc-evans.com/equipment/welding-support/v-root

Here's a video of offshore pipeline fabrication:    http://vimeo.com/86045182

There other players but Stanley CRC-Evans seems to have the most experience, is the fastest of methods production wise and in pipeline construction Speed is King! And this system is more widely used world wide... In this news release, Stanley CRC-Evans Offers Offshore Apprenticeship Programme (<--Note the spelling:grin:) to Prepare Apprentices with Skillset for a Successful Welding Career... Here's the link below:

http://www.crc-evans.com/crc-evans-offers-offshore-apprenticeship-programme-prepare-apprentices-skillset-successful-welding

This last video sums it up quite nicely... CRC-Evans partnered with Australia's three largest diameter CSG to LNG pipelines... Here's the link below:

http://www.crc-evans.com/crc-evans-partnered-australias-three-largest-diameter-csg-lng-pipelines

From the Pipeline & Gas Journal... "CRC-Evans Automatic Welding Introduces Laser Vision Welding System" Here's the link to the article below:

http://www.pipelineandgasjournal.com/crc-evans-automatic-welding-introduces-laser-vision-welding-system  

Their only real competition with respect to applying advanced technologies is from McDermott Automatic Welding Systems and their capabilities... They use Lincoln Electric welding equipment exclusively with their own "JBBS - AUTOMATIC BUG AND BAND WELDING SYSTEM': "Our state-of-the-art system is a modified version of the Vermaat Technics
Veraweld system. It incorporates the latest developments in pipeline welding technology including Lincoln Electric PowerWave power supplies..." And then there's the "JAWS - AUTOMATIC WELDING SYSTEM" - Our JAWS Automatic Welding System combines state-of-the-art technologies in welding, servo systems and computerized controls, and is typically used on larger diameter and longer pipelines... Here's the link to both:    http://www.mcdermott.com/News/Publications/McDermott_Welding.pdf

Here's another article:    http://www.berkeleyprocess.com/documents/white_papers/jaws_automated_pipe_welding.pdf
 
To be fair Magnatech recently started to offer orbital pipe welding equipment that can be mated to many of the major welding power source manufacturers for GTAW... Here's the link to their main home page:    http://www.magnatechllc.com/     Here's a link to their Mechanized Welding Systems for Gas and Water Pipelines:

http://www.magnatechllc.com/markets-pipeline.php    Here's just one of the application stories describing a gas project in Saudi Arabia and showing how their equipment can be mated with one of the most popular welding power sources in Germany IMHO (Looks like a Fronius to me!:grin:) also:     http://www.magnatechllc.com/applications-pipeline-cross-country-gas-pipeline.php    I don't know but, I could swear that it's a Fronius power source for sure built for Magnatech and I think if one goes to the Fronius site, they would certainly find the matching system of probably one of the "Trans Synergic GMAW systems they manufacture... Here's their Pipeliner Welding Head below:

http://www.magnatechllc.com/Brochures/Pipeliner%20II%20609.pdf    And here's their EZ Orbital System Model 517 Controller with 1000 series weld heads... This controller was first introduced as a controller that could be universally mated with many of the most popular power sources to weld either GMAW/FCAW, or GTAW for a variety of applications and hailed initially as a revolutionary advance in orbital welding technology... However since it's initial introduction, the company has scaled and limited back it's capabilties to work with only one type of weld head and limited to fusion welding with no filler metal in GTAW only...

This is how Magnatech describes the system currently: "Magnatech introduces an innovative solution to orbital tube welding with it's modular EZ Orbital Welding Systems. The Model 517 is a tube welding controller that integrates the operation of a standard, commercial GTAW power source with the weld head. The new line of weld heads, the 1000 Series, with digital control of rotation speed regulation, ensuring perfect repeatability..." The problem with this system is that only GTAW autogenous welding  can be performed with this controller so it really doesn't fit an application to use in order to deposit a root pass for a pipeline tie-in joint if there's no filler metal...  And the weld head is limited to it's maximum diameter which is nowhere near the sizes required... There are more shown also in the Mechanized Welding Systems for Gas and water Pipelines link above...

Here's a relative newcomer from the UK that looks like a fine system to use but, not enough information is easily accessible... Automated Welding Systems Ltd... This system doesn't require you to use a proprietary welding power source... Any type of 350 Amp, 100% duty cycle CV power source or any similar trans-synergic power sources with at least the same output & duty cycle also... Here's the links:    http://www.weldingbug.com/images/logo.jpg     http://www.weldingbug.com/Product-Information/Specifications

Here are some other automatic pipe welding systems that are mainly using proprietary power sources and control modules... This one is from Tri-Tool:

http://www.tritool.com/adaptarc_pipewelding.asp

Automatic welding pipeline with the Lonestar system:

http://dyna-torque.com/

http://dyna-torque.com/automated-welding-system-single-head/

http://dyna-torque.com/lincoln-welders-vs-automated-welding-system-dual-head/

http://dyna-torque.com/miller-welders-vs-automated-welding-system-single-head-wf/

https://www.youtube.com/watch?v=7bmCJBc-0ic

https://www.youtube.com/watch?v=M1Pjrmv7qx0&list=UUfmMHRGAGM-W4_LZIBA-vlA&index=2

https://www.youtube.com/watch?v=uAPsGeA35dU&list=UUfmMHRGAGM-W4_LZIBA-vlA

https://www.youtube.com/watch?v=ZoL7z7KY1Wc&list=UUfmMHRGAGM-W4_LZIBA-vlA&index=4

Stainless stl. FCAW for a project in Russia:    https://www.youtube.com/watch?v=DSnh7tf8RnQ&list=UUfmMHRGAGM-W4_LZIBA-vlA&index=9

This movie shows a Split tee connection to a gas transportation pipeline:

https://www.youtube.com/watch?v=XYz2GktSMeA&list=UUfmMHRGAGM-W4_LZIBA-vlA&index=12

Here's Lonestar's Australian website:    http://www.lonestarwelds.com.au/    More vidoes:    http://www.lonestarwelds.com.au/video.htm And some of their projects below:

http://www.lonestarwelds.com.au/projects.htm   

Here's a brochure showing the Lonestar pipe welding equipment set up mated with a Miller power sources and wire feeding equipment:

http://www.lonestarwelds.com.au/Lonestar%20Brochure.pdf

And the this list would not be complete without including Bugo Systems originally from Pittsburgh, PA...  Many industries have used Bugo equipment for a variety of applications... However, We're going to focus on their pipe welding equipment starting with the Piper-Plus Pipe Welding System... here's the link to the main page with video's and product information:    http://www.bugo.com/component/products/?view=product&id=14    And the Piper Bug Pipe Welding System below:

http://www.bugo.com/component/products/?view=product&id=13    Here's their main home page:    http://www.bugo.com/

Welding Automation, Welding Automation Systems, Automatic Carriages Featuring Gullco Pipe KAT Rigid Track Systems:

http://catalog.gullco.com/Asset/Pipe%20KAT%20-%20Rigid%20Track.pdf

http://catalog.gullco.com/product/orbital-welding/pipe-weldig-carriage-pipe-kat-rigid-track

http://lib.store.yahoo.net/lib/yhst-128216191812058/gu-pipe-kat-orbital.pdf

From ORNL = Oak Ridge National Laboratories originating way back in 1973 their development of the ORNL Automated Orbital Pipe Welding Systems...
Abstract: The Oak Ridge National Laboratory has developed and successfully tested an improved automated welding system that has demonstrated reliable performance in making nuclear quality welds on pipes from 3 to 16 " outside diameter. This equipment also shows promise for remote control of reactor maintenance operations of pipe cutting, beveling, and welding in high-radiation zones where personnel cannot enter.The equipment was adapted from an orbiting automated pipe welding system originally designed
for the Air Force by the North America Rockwell Corporation. Automation of the equipment permits complete welds to be made from preset programs fed into an electronic programmer-controller. ORNL developed improved controls that can sense changes from feed back signals and automatically adjust for pipe ovality and for irregularities in the geometry and wall thickness at the prepared edges of the pipe joint.The automated controls also compensate for the difference between welding upward or downward in the SG(pipe horizontal) position, as the carriage moves a gas tungsten-arc torch continuously around the pipe... Here's the rest of the paper:

http://moltensalt.org/references/static/downloads/pdf/ORNL-4830.pdf

And here's an article covering the history of: "Automated pipeline welding systems: past, present and into the future" in The Australian Pipeliner, July 2011:

http://pipeliner.com.au/news/automated_pipeline_welding_systems_past_present_and_into_the_future/061418/   

I believe this is the original article below and Bob Teal is a legend in pipeline welding:     http://teale-pipeweld.com/papers.html     http://teale-pipeweld.com/index.html

http://www.teale-pipeweld.com/PDF/papers/Automated_pipeline_welding_systems-2.pdf

http://teale-pipeweld.com/PDF/papers/QUALITY_UT_ECA-Guide_3-9-2012_Rev1.pdf

Here's an interesting article from Lincoln Electric that's an application story: "Pipeline Equipment Manufacturer Finds 87 Percent Time Savings In Automated Welding":

http://www.lincolnelectric.com/en-us/support/application-stories/Pages/pipeline_manufacturer_automated_welding.aspx

Here's Lincoln Electric's own line of Orbital pipe welding equipment... This system includes a PowerWave S500 power source:    

http://www.lincolnelectric.com/en-us/Equipment/Pages/product.aspx?product=K52082-1

Here's some more of the same type of orbital pipe welding equipment from Lincoln:   

http://www.lincolnelectric.com/en-us/equipment/orbital-systems/Pages/orbital-systems.aspx   

This is from Fronius International titled: "How to melt a welder’s heart when the mercury plummets way below zero" “Cranfield Automated Pipe welding System” – is a special GMA welding process based on tandem technology and developed specifically for pipeline construction by Cranfield University. CAPS makes pipeline welding faster and more economical, while coping with harsh environmental conditions such as bitter cold... Stephen Blackman, Director of Welding Engineering at Cranfield University’s Welding Engineering Research Centre in England, has been using Fronius tandem GMAW systems since 1997. In 2001, BP were looking for a welding process that could significantly reduce the cost of pipeline construction. Laser welding and one-shot welding had failed to deliver, and BP consulted a group of industry experts for guidance.

As an acknowledged expert in the field, Stephen Blackman, had the answer in tandem GMAW. BP liked his ideas and set Cranfield a challenging target – to develop and field-test a mechanised tandem GMAW pipeline welding system within 18 months. BP had one other requirement: the field trials had to be performed in winter under Arctic conditions.
This latter requirement was based upon the target pipeline project. The new process had to be suitable for use on the proposed long-distance gas pipeline known as the Alaskan Gas Pipeline. This is a 5700 km long pipeline between Alaska and Chicago, and at a predicted cost of USD 16 bn it will be the largest privately financed project in North America." Here's the link below:    

http://www.fronius.com/cps/rde/xchg/SID-76598F01-8CCB3962/fronius_international/hs.xsl/79_11684_ENG_HTML.htm

Mechanization and Inverter Welding Technology Lend Speed to the Laying of a Major Gas Pipeline

Spread four has bugs in the cornfield - but not to worry. The "bug" referred to here is a mechanized welding bug (Fig. 1), specifically a single welding head, computer-aided gas metal arc (GMAW) system from CRC-Evans Automatic Welding powered by a Miller Electric XMT® 304 inverter-based welding machine. The bug operator and owner of 32 inverters is Welded Construction, L. P., of Perrysburgh, Ohio. Spread four is a 147-mile stretch of the Alliance Pipeline system (Alliance) cutting through the cornfields of northeast Iowa...

http://www.millerwelds.com/resources/articles/Pipeline-Construction-Utilizes-Mechanized-Welding

VERAWELD® "Welding System" The 'Veraweld' automatic welding system was developed in 1991 for automatic welding of pipelines with the aim to provide assured quality of each and every pipeline weld...n 1991, Vermaat Technics was approached by various pipeline construction contractors, to develop an automatic welding system that ultimately could support the companies goal to build world’s fastest and most reliable automatic welding system.
To ensure the welding system would indeed provide the essential backbone in supporting the considerable production rates such a massive capital investment requires, the system had to be developed well in advance to ensure a track record that confirmed quality, flexibility, productivity and above all, reliability.

Key requirements were: Pre-programmed parameters for each pass and every location with adjustable tolerance; Able to use multiple welding processes and all welding directions; All passes applied externally to allow use on all pipeline diameters; All systems identical and able to weld all passes; Optimum maneuverability for the welders by using remote control and light weight bugs; Use of standard market components where feasible... Here's the link below:

http://vermaat-technics.nl/wpage/43/veraweld-history.html

http://vermaat-technics.nl/product/146/welding-bug-dual-torch.html

RMS Welding Systems currently employ two external welding systems, depending on the desired production and project budget. The first being MOWI, which is a single torch, spool on board system, the second being the MOWII, which can be used in many configurations and is completely digitally controlled. The two systems are versatile and can be used in many varying applications...

Both systems clamp onto a specially designed band and have adjustable carriages that can be used on 12’’ to 56” diameter pipe. With some slight modifications they also have the capability of welding inside larger diameter pipes with the welding band... Here's the link:

http://www.rmsweldingsystems.com/Equipment/ExternalWelding/tabid/64/Default.aspx

Internal Welding Machine link:

http://www.rmsweldingsystems.com/Equipment/InternalWelding/tabid/63/Default.aspx    

You know how folks say: "Save the best for last?" This equipment I must say if it is as good as advertised, then I'll have to retract my original best choice being the Stanley CRC-Evans systems and replace it with the observation that these Vallourec Serimax pipe welding and clamping systems sure look superior in design at the very least and yet the proof is going to always be in the pudding as far as how they can handle the daily wear & tear these heavy duty systems are exposed to, so may the best system win!:grin::lol::cool: Here are the links:     http://www.serimax.com/en/technology/welding/      These links below also:   

http://www.serimax.com/assets/Uploads/Equipment/SATURNAX09-Datasheet-BD.pdf     

http://www.serimax.com/assets/Uploads/Equipment/EXTERNAX-Datasheet-BD.pdf

Oh, and I almost forgot this paper from Finland on advanced orbital pipe welding systems:

https://www.doria.fi/bitstream/handle/10024/90160/Adaptive%20Orbital%20Pipe%20Welding%20-%20Hamidreza%20Latifi.pdf?sequence=1

Well, that's it for now... Enjoy the reading and movies!:lol::yell::twisted::yell::lol::grin::smile::wink::cool:

Respectfully,
Henry
Parent - - By S J (**) Date 11-04-2014 14:21 Edited 11-04-2014 19:23
???

And, what did we (in the US) learn from the childhood book "Mike Mulligan vs. The Steam Shovel"???

Will the debates never end?

Sorry, I don't recall the wall thickness for X70 offhand, so Magnetech's GTAW/(TIG) orbitals might be N/A - but thank you for posting all the interesting information.

As for short arc welding of (high pressure or low pressure?) pipe, again, the questions related to fusion and impact test results might be wise to address - and, at the end of the day, the most practical answer might depend on the in service conditions and how many contingencies or worst case scenarios the contracting authorities need to plan for. But, he did say that x-Ray inspection is used, so LOF would likely be captured by a qualified radiographer.

The whole issue of ambient temperature conditions throws a new curve-ball though - maybe some folks that have actually been on site can chime in and guide us.

I am aware of one person who ostensibly worked on the Alaska pipeline project - in the summer time.

Oh, I just remembered - some automated GTAW welding controls offer the capability of running a low power warm up pass - AKA preheat???  And, let's not forget about the recent advances in digital temperature measurement, yada, yada, yada,

So, is X-70 even the optimum material?

But, this mostly about money (or health and food), and practical solutions are wise to consider.

Edited spelling error - there might be more, sorry.
Parent - By jwright650 (*****) Date 11-04-2014 14:35
I remember AWS had an article in the Journal about welding and inspection on the North Slope (it mentioned the associated problems of maintaining preheat and material specs...etc) awhile back.

Click the link to read it:
http://www.nxtbook.com/nxtbooks/aws/wj_201206/index.php?startid=62
Parent - - By 46.00 (****) Date 11-04-2014 15:00
I'm guessing a wall of text here?
Parent - - By S J (**) Date 11-04-2014 19:21
Indeed, a wall of text!

I suppose the bottom line is that most material things decay over time - according to the law of entropy; and, there is also sometimes the option to repair and/or restore.

I did visit Magnetech's orbital welding website, and I did review some of the information posted there about their orbital GMAW and FCAW systems - one key consideration might be related to how easy the gas nozzle clogs are to clean - vs. for a manual FCAW welding torch.

I am not sure what to make about some of their "pre-heat" advice, and I was unable to locate that pitch on my second visit (to the website).  And, GTAW preheat might not even be worth the experiment - except maybe for a thin wall tube.  ;)

This one is not for me to call - the powers that be are perhaps better informed and better able to make the right decision(s).
Parent - - By ssbn727 (*****) Date 11-04-2014 20:38 Edited 11-04-2014 20:49
S J,

When did it become your call in the first place? MStevens is the person to make that call... I think you're getting ahead of yourself son.:lol::yell::twisted::yell::lol::yell::twisted::yell::lol::roll:

Yes indeed it is a knowledgeable wall of text... If it bothers you then I have a simple suggestion for you... Don't read it all if you wish but remember this, you may miss out on something very relevant to the knowledge you seek if you ignore it all together!:eek::eek::eek::roll::roll::roll::lol::yell::twisted::yell::lol::yell::twisted::yell::lol::yell::lol::grin::smile::wink::cool:

Magnatech isn't a major player in the automated pipeline welding systems market... In a lot of other industries they surely are but not in transmission pipelines... CRC-EVANS is the leader of the pack INHO!

Respectfully,
Henry
Parent - - By S J (**) Date 11-04-2014 22:26
Sorry, my bad - perhaps I should have said "we" and let the chips fall wherever they may relative to who feels included or not in the term "we".

A large part of my frustration stems from the proper definition of the weld joint configuration:

You wrote in your earlier post:

"5.) Normally the butt groove joints are open root since it's carbon steel as opposed to a 300 series stainless steel to use as an example mainly because of the chromium content which would result in "sugaring" of the root surface as well as possibly contaminating deeper from the root surface... Therefore requiring a purge with stainless steel GTAW..."

Correct me if I am wrong, and let me demonstrate my ignorance then.  If my memory serves me correctly, the AWS standard for welding joint terminology once defined butt and groove joints differently - but, perhaps not.  The terms square butt vs. groove weld would enable us to more clearly debate the available process option advantages and disadvantages.

But, he did say, he was using 7018 and the SMAW process for the fill passes, so maybe we need to consider whether this debate is useful to website visitors who might wish to learn more about pipe welding, or whether we are wasting time.  And the thickness would certainly be a heavy hitter relative to the power requirements (and metallurgical restrictions) necessary to properly qualify a one-pass orbital GTAW square butt weld.

Also, the ASME spec is only available to those folks willing to ante up $225. It might be available through IHS with an AWS discount - but, I have not checked.
Parent - By 46.00 (****) Date 11-04-2014 22:35
Hey! Please stop saying Sorry! Thats all I see on this site now a days!:lol: He dont own this site!
Parent - By ssbn727 (*****) Date 11-05-2014 08:53
I can see why you might be confused but remember this... The OP mentioned that they were using 48" diameter, schedule 80 pipe which has a nominal wall thickness of .500" to .668"...

"Square butt groove joint" is not AWS standard terminology and, it isn't required to use with M Stevens's job because the work is to the API pseudo-standards instead of any AWS D1. welding standards. so the use of those terms is appropriate.:eek::lol::grin:

Respectfully,
Henry
Parent - By ssbn727 (*****) Date 11-04-2014 19:57 Edited 11-04-2014 19:59
Your "weldcome" as I post it yp for anyone reference to use at a later time... For your information , Magnatech is not exclusively GTAW S J... They are pretty much heavily involved with GMAW/FCAW systems for secondary lines where X70 is probably used more often... The mainlines are all X80 and above for some time already especially in Europe, and is the current preference for mainline work these days... There are a few manufacturers of automated pipeline welding equipment that are using exclusively GTAW all the way out...And for an example Ed Craig's  new hot wire TIP TIG system welds @ some impressive deposition rates for hot wire TIG...

However, the overwhelming majority of the main lines and large diameter secondary lines starting form 20" and up to 56" diameter pipe main lines are welde with a form of modified short circuit such as CMT, RMD, STT and other brand name modified shot circuit methods of metal arc transfer for the root pass and then either synergic pulse GMAW all the way out or, hot & fill with GMAW-P and, with another tractor that snaps right on to the carriage in a few seconds or less, deposits the cap passes with FCAW hooked up to a separate lead that's connected to either one of their proprietary power sources or any of the major power source players multiple process AI & fuzzy logic synergic huckleberries that will even pour you a cold one after your done if you program it correctly!!! Seriously, the equipment being used in the current state of the art automated pipeline welding systems along with the choices of power sources along with the multiple microprocessor controls throughout the main components is truly impressive compared to only a few decades ago...

The equipment I used to go around setting up , troubleshooting, and repairing back them were nowhere near as sophisticated as some of the major players in this racket and Mr. Teal does a good job of categorizing all of the manufacturers of automated pipe welding equipment and systems at various levels starting from the top with CRC-Evans and all the way down to a level that is  marked: "Not Recommended'" for onshore oil & gas transmission pipelines and Magnatech unfortunately was one of the manufacturers on that level...

However not all pipe joints are exclusively for for that type of construction and players like Liburdi, Magnatech,  AMI, Orbimatic, and some relatively new player like  Lincoln, and ESAB as well as a few others manufacture some really really intricate and sophisticated orbital pipe welding systems for both Autogenous as well as consumable filler metal welding from very thin walled and tiny diameter tubing all the way up to 2" thick seamless pipe found inside nuclear power plants and are able to weld any ferrous or non-ferrous metal  that's required to weld...

the cool factor ofal this is that the amount of transmission pipelines that are to be constructed are at the very least twice as much as what has already been constructed and it sure does mean that there will be a high demand ofr skilled automated pipeline welding technicians capable of operating this type of equipment which is also one of the reasons that some of the manufacturers are designing the new crop of systems with very user friendly programming set ups and one company has even eliminated the need for the operator to be proficient in what the current systems as well as some of the older equipment requires from them...

This enable. the owner of the equipment to rapidly train the operator t be proficient in operating these newer self-programming automated pipe welding systems... Another improvement is the adaptability of these systems with any of the major welding power source manufacturers which does make it more user friendly and the capability to design your own wave forms according to each specific application or even a specific type of joint whereby multiple waveforms are used in sequences throughout the various parts of the joints...  To ramp up or down current, voltage,  travel speed, wire feed rate, CTWD's at various rates to compensate... And the capabilities to change those inputs so that there's more overall as well as detailed control of the heat input and cooling rates especially for certain metals... And for specific service conditions where detailed,specific along with flexibility on the fly with control is of the up most importance! That level of specificity and customization wasn't available back in my day when I was out there pounding the docks, and power plants and pretending I was a contortionist... :eek::grin::lol::yell::twisted::yell::twisted::yell::lol::yell::smile::wink::grin::cool:

Besides, I do enjoy it when a thread continues to grow and grow!:eek::eek::eek::grin::cool: EDIT: Wow! look! No links posted in the entire post! Now that's a rarity indeed!:eek::roll::grin:

Respectfully,
Henry
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