Welding Chromo in a power plant

[fillncap]

the guy seems to be welding food hygine/dairy pipe 1.5mm wall ,closed square butt no filler.the finished result looks like orbital work

fnc

[Pressure_Welder]

lol i could teach my dog to walk the cup with no filler on thin wall pipe. Must be a preheat with that thinwall stuff with no filler? I work with heavy wall pipe almost 100% of the time, almost garunteed to get cold cracking if you dont use filler on that stuff. Ohya just some other chrom-moly info if it will help you at all? On all our P11 material their is a 400* minimum preheat that must be maintained throughout the welding process root/fill/cap. On some of our major steam lines running to the turbines and other auxillery lines their is also post heat treatment required, we use a cooper heater with ceramic blankets, ramp up to 400* and go 200* every hour till 1350 is reached, then a 1hr soak peroid at 1350, then 200* an hr back down to 400*. Nice to get on that gravey train haha, i believe i started the job at 7:00am finished my 3 joints by 3:00pm. xray's completed by 4:00. Then a 14 hr heat treatment process all triple time! haha was a little tired at the end but was worth it!

[fillncap]

Originally Posted by Pressure_Welder

What pressure were the lines under? I work with super heated steam lines in excess of 1500psi, if its the tubes in the boiler they dont get too excited just a mag-partical test because its in an enclosed structure. But all the exposed major steam lines that people walk by every day they go insane as far as quality control. If somthing ruptures and anyone is even remotely near by, may as well nail the coffin shut! Super heated steam depleats any sort of oxygen around, not to mention will burn your skin right off. Scary stuff in my opinion.

hi pw
a few years ago i used to work for dresser ,fabing maxiflow type valves and pipework for the power station turbines.
there was an accident with a line bursting,one of the guys was 60ft above the line when it went. it nearly killed him,90% burns,f**ked his lungs ,now he is in a wheel chair.parts of the line were never found!!!
im not sure what the pressure of the line was.the stuff we was working on tested to 3500psi prob giving a swp 1500psi ,if im right i think the working temp was 600+ deg c ,like you say pw chromo needs to be spot on even so with the electrode identification, ie E9018 just tells you 90,000tpsi 18-ironpowder low hydrogen.it is important to get the material analysis part right.

ie E8018-B2 1 1/4 cr

E8018-B8 MOD 9cr

if i remember these pics ws 1 1/4 cr tig root,fill,cap.

[grumpy]

You know what would be nice? To have someone do a short or long for that matter video of how to walk the cup for those of us who don't know how. It really doesn't have to be done with power to the torch maybe one in broad daylight and a close up. Heck, I don't even have a tig. But, I'm not really thinking about me so much as those of you who do have tig machines and would like to know.

Anyone up to the task? I would but like I said I don't have tig, never welded with tig, and to tell the truth I have put electrode to metal only once in the last 12 months.

[Pressure_Welder]

Those look like excellent caps.

[Dman033189]

Originally Posted by Pressure_Welder

What pressure were the lines under? I work with super heated steam lines in excess of 1500psi, if its the tubes in the boiler they dont get too excited just a mag-partical test because its in an enclosed structure. But all the exposed major steam lines that people walk by every day they go insane as far as quality control. If somthing ruptures and anyone is even remotely near by, may as well nail the coffin shut! Super heated steam depleats any sort of oxygen around, not to mention will burn your skin right off. Scary stuff in my opinion.

Well I was never really told what pressure they were running, I thought I heard the boss say something about 1,300 psi and he might have also said it was a blowdown? but Im not sure he just pointed at it and said he wanted it replaced....

[Dman033189]

Originally Posted by flange jockey

tom, jay would yourself, dman or pw consider explaining how you personally walk the cup, i have tried numerous times in the past and know ill never get it, it would be the better technique for walker to practice.f/j

I have done very little walking the cup so far, I just took the first welding cert ( 6g 2" double extra heavy 6010/7018) I am waiting to hear on the xray results for that. Then in Januraury I will be working like crazy on walking the cup in class, so maybe I will be of more help after that!

[flange jockey]

no prob lads, as grumps suggests perhaps someone else.d man, all the best on the test, and your future. f/j

[fillncap]

Originally Posted by flange jockey

no prob lads, as grumps suggests perhaps someone else.d man, all the best on the test, and your future. f/j

hi flange
i will do video for you in the next couple of days mate,iv moved house and not been working.hence no machine to use.lol

fnc

[wayne64]

Walker, from what I've done years ago. New construction was usually the the toughest weld standards on main steam 1-1/4 % chrome. Tig root, X-Ray, first up hill pass with 8018 or 9018, X-Ray, then depending on the schedule X-rays every few passes. Also understand these were all hot joints, meaning the joint was brought up to temp and the cooper coils kept it hot till the joint was done then slowly brought down to stress relieve. The heaviest wall I welded was 4" on 14" pipe and that weld took almost a week with shifts. Now repairs and upgrades the standard could be anywhere on the chart from slash and burn to full X-ray with hot joints.