Critical Steam pipe job.

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Good morning all! well another huge scale job was just given to us today, just going over the prints. We are to replace our steam loop pipe system on our turbine. Its 8" (1-3/8" wall) P91. Its all pre forged particular bends which match our turbines configuration, 10 weld joints, tig root and stick fill/cap. However! i must say in all my welding years this is the first time i have encountered this particular joint prep, i have dealt with mostly j-bevels which come to a feather edge. I am having a hard time understanding how we are going to put in a successful tig root on a joint prep that has a 1/4" land essentially. Again were just in the infant stages of preperation but i thought i would inquire as to weather anyone has encountered this particlar joint prep on heavy wall. I know everyone seems to be going to narrow v-groove welds on heavy wall these days, but definatly the first time ive dealt with this joint prep. Attached Images
Reply:Will the codes let you thin out the land a little? I would guess that to do a root pass with full penetration on 1/4 would take a large amount of amps and a fairly nice nice gap. I also have never encountered this i'm just guessing.Lincoln pro core 125 14''chop saw7 inch grinder,2-4.5 inch grinders,electric die grinder.Half inch drillAnd alot of hand tools
Reply:Pressure_welder,That looks like a joint prep for a mechanized welding process, not a manual TIG and stick welding procedure.  That said, I've yet to see a process outside of subarc welding perhaps, that could guarantee CJP with a 1/4" land and zero root opening.Something doesn't add up here...Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:hey guys,The picture simply shows the type of joint on the piping, however it will absolutely have a gap for the root, that would definatly be a huge job to touch up all the faces! would almost need to be re-machined.
Reply:That looks more like a joint configuration for an orbital welding set up.Edit: oops - I see it is GTAW. Qualify your procedure for a smaller landing. Communicate with the vendor that supplies the fabrication to see if you can get the joint configuration to match whatever your procedure parameters are.Welding P-91 is quite technical. Good luck. Tip: bake out your base material very well.Last edited by weldertom; 01-15-2014 at 03:56 PM.
Reply:we have been switching some of our older parts that have reached their max heat cycles from 2.25 chrome to P91, definatly a new monster but like anything else its just metal that needs to be welded properly. This piping that arrived came from Alstoms "grocery store" as it were of parts they have for turbines they've made, so MAYBE it is an orbital situation, however when it was constructed in the 1950s orbital was not around! If shes an orbital job were out of our league just not setup to do that. Were manual guys! But yes i just cant make sense of a 1/4" land for a tig root
Reply:I've seen that style of compound bevel for mechanized welding with a bug and FCAW or solid wire GMAW; in the cross-country pipeline industry.   That land is not typical, but the bevel angles are something I've seen before.  You'll not weld those joints by hand with any process, except maybe stick.  And that narrow groove just screams lack of sidewall fusion with stick...Is that 1/4" land paired with some kind of consumable insert?  I don't know much about orbital TIG, but maybe that's the missing piece of the puzzle?Any way you slice it, you have my condolences for welding those joints.  The pre-heat and interpass will be murder; and the PWHT won't be much fun either.  Are you using induction heating in your operations?  If not, I strongly encourage you to check it out for this job.  You'll probably need something else for the PWHT, but for pre-heat and interpass temp maintenance, induction heating will make your life easier.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Originally Posted by Pressure_Welderwe have been switching some of our older parts that have reached their max heat cycles from 2.25 chrome to P91, definatly a new monster but like anything else its just metal that needs to be welded properly. This piping that arrived came from Alstoms "grocery store" as it were of parts they have for turbines they've made, so MAYBE it is an orbital situation, however when it was constructed in the 1950s orbital was not around! If shes an orbital job were out of our league just not setup to do that. Were manual guys! But yes i just cant make sense of a 1/4" land for a tig root
Reply:yea we have an in house p91 with a j-bevel and straight v groove. Our engineers will have to get their ***'s on the phone!
Reply:I orbital weld, I've welded my share of 9 chrome but never seen such a land. We typically tig about three passes in our heavy stuff then sub arc out but no way is a 1/4" land conducive to any tig hand or orbital I've encountered. Something isn't jiving here.
Reply:No offensive to you or your guys but are you qualified to weld this ?  Is this all x ray work too ?
Reply:@ Pressurewelder - are you aware of the article http://www.fabricatingandmetalworkin...t-preparation/ ?  Check out Figure 6.  The article's authored by a PE at Lincoln Electric.  Give 'em a shout.Curious why no root opening on the joint?  The article suggests the compound angle is to mitigate crack propagation.  The joint's narrow included angle does, however, suggest non-human welding process as mentioned above by others.  Scanned the 2000 ed. of the Procedure Handbook and didn't see any similar joints in the submerged arc section.  Curious....Last edited by ManoKai; 01-15-2014 at 08:01 PM."Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi
Reply:I'm assuming you have a pressure pipe ticket in Tig and stick?Clan you feather edge the land with a die grinder?JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:Originally Posted by snoeproeI'm assuming you have a pressure pipe ticket in Tig and stick?Clan you feather edge the land with a die grinder?
Reply:As to the people asking if Pressure Welder is qualified, look into his older posts. Try not to insult him so readily. I was trying not to laugh. Yes he is very capable of welding on high pressure pipeing systems. Just "taking a grinder and feathering out the edges?"   Critical pipe joints in coal fire and atomic plants are usually machined. Not slap dash cut with a torch and fixed with a hammer.  The coal fire plant in my home state, the joints were machined J-bevel. Keep us updated. This is interesting.Local 83
Reply:Hey fellas, the picture I posted was actually just off the internet to explain the general concept of what I am reading on my prints (not actual measurements), and of what I can see from the actual piping we have siting on the turbine floor, certainly looks like a PITA to weld out. The pipe is actually from Europe. Agreed all of our heavy wall items are machine j-bevels, generally "almost" feathered. we tend to like working with a 1/16" land. I will totally agree it would be impossible to throw in a successful root sitting at a 1/4" land, definatly confused but we will converse with our engineers tomorrow. Also just for peoples general information when something is spec'd a machined bevel, almost 100% of the time your not allowed to doctor that bevel up at all with a grinder. When its an exposed super critical line like this the rules and regulations become 10x more strict as compared to say a repair in the boiler, The print does call for a tig root/ stick fill, fusion on the bevels will be a monster! and no worries fellas! we maintain 6 different pressure tickets annually. however! their will likely be a procedural test, then a qualification test for this particular job. I must admit ive worked on some critical lines in my time, and even thicker material. But nothing this crazy. According to the engineers in our thermal sector, if this loops fails the force of the super heated steam at 4000PSI will completely demolish the turbine house, dissipate all the oxygen in the plant, and boil anyone within 300' from the inside out. call me crazy but that's why I love my job!!
Reply:^ second to last sentence ^  = brutal facts and motivation for welding perfection to prevent seeing the grim reaper.  Zero room for error.  Humbled."Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi
Reply:Originally Posted by Pressure_WelderHey fellas, the picture I posted was actually just off the internet to explain the general concept of what I am reading on my prints (not actual measurements), and of what I can see from the actual piping we have siting on the turbine floor, certainly looks like a PITA to weld out. The pipe is actually from Europe. Agreed all of our heavy wall items are machine j-bevels, generally "almost" feathered. we tend to like working with a 1/16" land. I will totally agree it would be impossible to throw in a successful root sitting at a 1/4" land, definatly confused but we will converse with our engineers tomorrow. Also just for peoples general information when something is spec'd a machined bevel, almost 100% of the time your not allowed to doctor that bevel up at all with a grinder. When its an exposed super critical line like this the rules and regulations become 10x more strict as compared to say a repair in the boiler, The print does call for a tig root/ stick fill, fusion on the bevels will be a monster! and no worries fellas! we maintain 6 different pressure tickets annually. however! their will likely be a procedural test, then a qualification test for this particular job. I must admit ive worked on some critical lines in my time, and even thicker material. But nothing this crazy. According to the engineers in our thermal sector, if this loops fails the force of the super heated steam at 4000PSI will completely demolish the turbine house, dissipate all the oxygen in the plant, and boil anyone within 300' from the inside out. call me crazy but that's why I love my job!!
Reply:Do they make the welders stand in front of the weld joints when it gets pressurized?
Reply:Weldertom-Yes the pipe still has a 1/4" land at the bottom of the bevel, i just added that picture to describe the joint i am dealing with. (PITA = pain in the ***) We are still suspiscious! hahaha its a erie feeling walking by any of these lines when were running! I have a severe respect for steam pressure.
Reply:Originally Posted by Pressure_Welder We are still suspiscious! hahaha its a erie feeling walking by any of these lines when were running! I have a severe respect for steam pressure.
Reply:I hate welding chrome. Too damn hot, you got all that snow from the Kaowool flying around in the air, plus it has a weird smell to it that makes me nervous.Do you guys have to use respirators while welding? Last chrome job I was on had to be TIGGED all the way out because of all the hex chrome hysteria.
Reply:WELL! i apologize in advance fellas, we were forwarded the wrong blue print obviously, all of our pipe showed up today on the truck, and evidentaly has the correct preperation for a successful tig weld. However still a tricky fill with such steep walls. Timmy-DEFINATLY will be wearing our speedglas fresh air welding helmets where ever we can, the top loop will be fairly accessible, but the bottom section is going to be a monster, inter-twined in all sorts of pipes/up against concrete walls, seperate the men from the boys that section! Were recruiting 4 other welders in our system to come aid in this, roughly 24hrs to finish a joint and cant stop once we start. HHere are some pictures for those who are interested Attached Images
Reply:few more, shows the piping on the turbine govenors, all the wrapped stuff is being replaced. Attached Images
Reply:Had a gut full of  p91 and 347 heavy wall.  Hex chrome socks,  I get plugged sinuses. Sent from my DROID RAZR using TapatalkLong after the price is forgotten, the quality will remain.Both of my Poppy's 1954 Short Hoods -Third generation to weld with it and teaching a fourthSA 2## - Bought and sold more than I can remember or care to list, 8 in the shop right nowGood on you guys. I googled up a writeup on welding P91 and is quite a process. http://www.thefabricator.com/article...r-power-plantsWeld like a "WELDOR", not a wel-"DERR" MillerDynasty700DX,Dynasty350DX4ea,Dynasty200DX,Li  ncolnSW200-2ea.,MillerMatic350P,MillerMatic200w/spoolgun,MKCobraMig260,Lincoln SP-170T,PlasmaCam/Hypertherm1250,HFProTig2ea,MigMax1ea.
Reply:definatly quite the process indeed, going to be a very labour intensive job for us. But fun nonetheless! And we dont even touch this stuff without wearing a respirator, no sense in losing years off  your life for no reason.
Reply:That's a true J-Bevel, you don't see those too often. I've only seen them once in my 30 years of pipe welding, it wasn't fun. The pipe had sat in a laydown yard for several years and got all corroded, by the time you cleaned all the rust off the nub it was like trying to weld a razor blade. What a mess.I'm glad I don't have to weld that. I'm getting ill just looking at where that's going, those tie ins are gonna be a hot bitch.Last edited by TimmyTIG; 01-16-2014 at 07:48 PM.
Reply:I'll say one thing to keep in mind, when tig welding p91 it has a very runny puddle and it helps tremendously to set your downslope for a longer time than normal. 10 second downslope isn't uncommon to have good control.
Reply:Back feed like a mother,  hate those tight ones where the tiles are right on the bevel. Sent from my DROID RAZR using TapatalkLong after the price is forgotten, the quality will remain.Both of my Poppy's 1954 Short Hoods -Third generation to weld with it and teaching a fourthSA 2## - Bought and sold more than I can remember or care to list, 8 in the shop right now
Reply:I still want to be your apprentice, the things you do are are amazing.
Reply:haha yea its one thing if you can pre-fab some of the parts and only have a couple in-situ welds, unfortunately everything will have to be welded in place, or iam afraid shell never fit again! the one pipe you see below the governor, that particular joint has a flange, which sits about 12" away from a concerete wall. NOT to sure how were going to fill that with stick. may have to root it and pull it away.
Reply:Pressure Welder,On pipe that thick, have you all given any thought to using solid wire or flux cored wire where you have access?  I know wire feeders bring their own set of hassles in those kinds of cramped quarters.  But with pipe that thick I wonder if running wire wherever it was practical would be worth it?  Yes, it means qualifying another procedure and the welders; maybe there's not enough time to get this done?Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Originally Posted by Pressure_WelderAccording to the engineers in our thermal sector, if this loops fails the force of the super heated steam at 4000PSI will completely demolish the turbine house, dissipate all the oxygen in the plant, and boil anyone within 300' from the inside out. call me crazy but that's why I love my job!!
Reply:That prep is what we call a "f*ck up".  Narrow groove joints are common with heavy walled P91, but typically have a J prep with an extended land that's typically 1/16" or so for machine welds.  Someone who did the standard weld joint detail in the engineering department made a very expensive mistake.
Reply:supe-yes I can honestly say this will be the narrowest bevel I have dealt with on heavy wall, had some coupons made up by our machinist to the exact specs of the loop lines see how that roots on Monday. These are sent from Germany so god only knows what Alstom's technique is for this crap. We have a small variance of rod diameter/root opening. so ill be trying out a 5/32nd gap w/ 1/8 rod. From my experiences on pipe I am thinking were going to have to feed like a bugger or that thing will keyhole and fight us the whole way. all joints are 5g and 2g. Be interesting to see how the old pipe was welded, tough to say if they had this type of joint prep in the 1950's? But we can definatly garuntee that it was done manually. Iam definatly not as concerned about the root as I am acquiring proper fusion on the bevel once we switch over to stick. Just definatly not a manually friendly joint at all. Any examples of the p91 you've welded with a similar joint prep supe?- DAB,unfortunately were under alstoms welding procedure, so it will be the tig/stick procedure. Call me old school but I just don't trust mig when it comes to pipe out of position! I know it happens regularily on heavy wall just something about it that bugs me!haha and I don't know about chernyobl but people could be hurt/killed if things aren't done properly. But like I always say you could bring in a donkey to do the welding..... he still has to pass the xray! however just because someone pass's xray dosent mean the joint wont fail for some unforeseen reason, god knows I don't want to be anywhere near it, I personally find steam horrifying! I get to see its power inside the boiler after a blowout.Last edited by Pressure_Welder; 01-23-2014 at 08:36 PM.
Reply:I figured you might be bound by existing welding procedure, but I thought mentioning it might be worth it for some time in the future.  For sure, you need to go with a proven welding procedure and making a sound weld(whatever process used) is by far the most important thing.For the record, you can get all-position FCAW wires for P91 material.  They run on 75/25 and, performance-wise, are not so different from typical FCAW for mild steel.I hope you get the chance to post some pictures of the original welds and the installation of the new piping also. Originally Posted by Pressure_Weldersupe-yes I can honestly say this will be the narrowest bevel I have dealt with on heavy wall, had some coupons made up by our machinist to the exact specs of the loop lines see how that roots on Monday. These are sent from Germany so god only knows what Alstom's technique is for this crap. We have a small variance of rod diameter/root opening. so ill be trying out a 5/32nd gap w/ 1/8 rod. From my experiences on pipe I am thinking were going to have to feed like a bugger or that thing will keyhole and fight us the whole way. all joints are 5g and 2g. Be interesting to see how the old pipe was welded, tough to say if they had this type of joint prep in the 1950's? But we can definatly garuntee that it was done manually. Iam definatly not as concerned about the root as I am acquiring proper fusion on the bevel once we switch over to stick. Just definatly not a manually friendly joint at all. Any examples of the p91 you've welded with a similar joint prep supe?- DAB,unfortunately were under alstoms welding procedure, so it will be the tig/stick procedure. Call me old school but I just don't trust mig when it comes to pipe out of position! I know it happens regularily on heavy wall just something about it that bugs me!haha and I don't know about chernyobl but people could be hurt/killed if things aren't done properly. But like I always say you could bring in a donkey to do the welding..... he still has to pass the xray! however just because someone pass's xray dosent mean the joint wont fail for some unforeseen reason, god knows I don't want to be anywhere near it, I personally find steam horrifying! I get to see its power inside the boiler after a blowout.
Reply:dab- ill definatly be documenting the process, always like taking pictures and looking back on jobs ive done! so do the other fellas I work with. Still have a ways to go, likely be happening in the fall id imagine, LOTS of stuff to do before the actual job starts.
Reply:We weld p91 with that type prep and we never gap it. Turn up the heat and push the filler in there. You'll get a more consistent root than by opening it up. 175+ amps isn't uncommon.