i want to learn to weld...

[Coalsmoke]

Hey Greg, you bet I'm still around, I haven't been needing to do much wrenching lately on the '01. 5 so have been doing lots of reading and not so much posting. I may have to take a little hiatus here for a bit as there's not much work these days with the economy the way it is and luxuries have been trimmed out of our budget, but I'll be back. So far though the TDR staff seem to be lenient and seem to be letting me stay even though my subscription was up a couple weeks ago. There must be a grace period.



Speaking of grace, despite these times, by the grace of the great provider we somehow manage to pay our bills and have just enough to buy food each month. I figure this must be a lesson in humility, because it has definitely changed my mindset on some materialistic things. The things you never count on when you hang the welding hood up and go get one of them fancy crackerjack university parchments. One of my good rig-welding friends says I should start a rig again and this time advertise that instead of simply being a "professional welder" that instead I am a "Degreed Welder" I have the '01. 5 CTD up for sale. If I can sell it I'll be able to completely pay off one of my student loans that has been taking $800 a month out of our pockets (about 70% of our total income). I think I'll probably end up with a 1st gen, for economies sake and since I've tried all the other generations, may as well try one of them too. Change can be good



There are some pretty sketchy exhaust shops out there, somehow your story of the er70s wire on the SS tubing doesn't surprise me too much. Sort of like putting a 50 year roof on a house without a proper foundation. A lot of shops don't even know about the 98/2 gas for SS and wonder why 75/25 leaves ugly beads. I've never heard of a FC Stainless wire, but, it wouldn't surprise me if they could make one, probably just need a market demand for it. Those welding engineers can come up with some pretty impressive metallurgical concoctions these days. The days of using only 2 types of welding rod are gone.

 

[GiesJ]

I enjoy lurking on this thread. I've never see FC stainless but found this online:
http://www.kobelcowelding.com/New data/Pamphlet2/pamphlet2DW-Hseries.pdf

jason

 

[GHarman]

GiesJ, A geat place to lurk:-laf. I dont do any big jobs these days. Been doing a little metal artwork to keep myself in the shop. Glad to see you are still around. GregH

 

[Coalsmoke]

Hey Jason, thanks for posting that PDF. I bet the price tag on that stuff is a bit scary.

 

[rbattelle]

While we're on the subject of welding stainless, what do you guys think about stick welding stainless? Seems I've heard people suggest it doesn't work well, others say it's fine. I've never tried it, but can see myself wanting to try it in the future.

-Ryan

 

[GHarman]

On pipe, you have to do a purge or purge dam at the joint. Generally the root is put in with tig. Heavy wall section pipe can be readily stick welded using the proper filler metals such as 308L-15/16 for 304L stainless steel, for example. A weld procedure specification will call out the requirements. If you are doing this on your own, you will need to experiment. A wirefeed weld will give you less distortion. Again, this is the process I am familiar with. There may be new and better ways of making this type of weld. GregH



ARCALOY 308L-16



ARCALOY 308L-15

 

[Coalsmoke]

I second what Greg said.

 

[GiesJ]

For some of the thick walled stainless vessels I built for a Nuke plant we would tig the root inside and out and then crank with heavy SMAW. This was especially vital around several nozzles with repads. Worked great. For the main seams we would SAW the cover passes (semi-automatic).
jg

 

[GHarman]

Really big weldments and preheating/ S.S. Metallurgy

GiesJ, Did you have to preheat those sections before welding to control shrink stresses? At what temperature? Did you control the interpass temperature?

I know you have considerable experience in this area. I have not worked on large section weldments.



For those who dont have any experience welding stainless steel, be aware of sensitization. It is a temperature range that is time dependent (to hot, to long), Stainless steel becomes depleted of chrome in the HAZ. This allows chrome carbides to form in the grain boundaries and allows for intergranular corrosion. Here are a few links for you to browse. Hope this is helpful. GregH



http://files.aws.org/wj/2007/11/wj200711/wj1107-18.pdf



Austenitic Stainless Steel



MIG Welding Stainless Steel



Sigma Phase/embrittlement

http://www.cap-eng.com/files/87_06578_from_CD.pdf



Embrittlement

 

[GiesJ]

Pre-heat and interpass temps were both part of the WPS. The temps escape me right now but I was always having to make sure welders had temp sticks in their pockets.
On sort of a related note, has anyone welded with 'jet rod' I believe it is called. It is SMAW rod that is 1/2" and bigger, I think. A guy did a welding demo from Miller where he started this big-honkin rod and while everyone was watching under the shield he balanced the rod/stinger and walked behind the group while the weight of the stinger/leads ran the rod down...

 

[DValentine]

Jet rod is er7024. It is a flat position rod.

Good discussions going on here.


Dave

 

[GHarman]

7024 Lincoln Jet rod

Yep, ran 5/16" and 3/8" 7024 rod on plate-lap seams and horizontal fillets with A-36 base metal, API-650 code work. The power supplies used for that job were diesel powered Lincoln Commanders and an older Miller "Big 40" diesel unit for a backup. (It was amazing how often those Lincolns{rental units}would quit on us. Guess who had to give up their Lincoln and use the Miller:-laf? I think I could run that rod with any power supply that was presented to me). Wow, that stuff runs so smmmooooottttthhhhhhhhh:-laf. Lots of heavy slag. Very smoky! It is designated as an "Iron Powder rod". A horizontal fillet and flat lap is a piece of cake with this stuff. I know there are larger sizes of this rod available, but according to our WPS, the size listed was according to spec. .

As far as doing the balancing act for a "bead on plate", thats a sales gimmic , or a statistical anomoly, that only requires the heat set properly. You cannot preprogram gravity feed into a manual electrode holder to properly follow a weld joint. If I have to follow a joint and make a code weld, I am going to have my micrometer eye on every swirl and bubble in the toe and root of that weld as I follow the proper joint geometry with that correct heat setting. I dont like redo's or rework! If I fail to do that, I have failed as a welder. They will get my money, straight away! GregH

 

[brods]

While we're on the subject of welding stainless, what do you guys think about stick welding stainless? Seems I've heard people suggest it doesn't work well, others say it's fine. I've never tried it, but can see myself wanting to try it in the future.



-Ryan

Yes you can stick weld stainless and have it come out fine. Like most things it depends on what you want to accomplish. For general fabrication where corrosion resistance is not super critical just have at it. Remember to only use stainless wire brushes that have never been used on mild steel otherwise you’ll transfer mild steel material to the stainless (which will then rust). Also be aware when using some stainless rod that slag pieces like to randomly pop off while the weld cools. They have the annoying tendency for finding and sticking to any bare flesh, like the neck.

 

[DJW]

The first time I saw Jet rod was in 1955 it was also told it was new in the plant, they were general steel fabricators, high pressure vessels, structural steel, pipe etc. The Jet was used to cover multiple stringer passes and was called a cover pass, seemed used for appearance only as was never used to weld fillets or for any other use. About 20 years later was working at a shop mostly miscellaneous structural steel and Jet rod was used to weld Re-Bar, reinforcing steel bar to angles and plate for concrete work, I questioned the use of Jet but I was told they always done it that way and it was approved by welding inspectors. Later at another similar shop I was assigned to weld Re-Bar to foundation plates, the inspector was there to witness the welding as it was a Code job, and when I selected the Jet rod he questioned it, I related my experience at another plant so he said I'll let you weld one and we'll test it. I welded the rod then he slipped a piece of pipe over the standing rod and bent it at 90* until touching the plate, he said OK use it. I found it so much convenient to 7018 as the welds were short so it was a pecking job, a good job for a chicken.

 

[GiesJ]

Keep in mind that Jet Rod still has an AWS class (E7024 if I recall) and that the weld procedure will have specific call outs for the filler metal F number, spec, AWS class, size of filler, etc. The Welder Qual will limit the particular welder to various other parameters, most notable is position.

For True ASME Code work, at least the Code work I am familiar with, and with ASME Authorized Inspectors, you would either need to follow the WPS with supporting WPQ and PQR or qualify via ASME Code a new procedure.

 

[DJW]

Its strange, but sometimes say for instance a 5/32 LH rod can be used where the next size up of the same manufacturer is prohibited, I've asked at times but never had a satisfactory answer, could be the thickness of the job metal, say too much heat or deposit for thickness, but this was where multiple passes were required on fairly thick steel. Another, I was sent to weld hinges on a warehouse doors and the engineer's instructions were to use 1/8 7018 LH and to run 3 passes down-hand and one pass down-hand for other vertical welding. I questioned my employer as I never heard of 7018 LH to be run down-hand on a code job. Anyway I run the beads vertical as could finish the weld in one pass. Later I spoke to the welder who worked at the start of the building and he said the engineer's instructions were to use 1/8 7018 LH and to run all vertical beads down-hand, then he went on to say there was about one inch of water on the concrete floor, and with the welding inspector standing watching when inserting a rod in the stinger he dropped it, he then bent down and picked it up and reinserted it in the stinger and started welding, the welding inspector never said a thing, the building was a concrete tilt-up. Welding and Motorcycling, some strange tales seems common to both endeavors.

 

[Coalsmoke]

DJW, In my opinion, l/h downhill is simply a case of an engineer who didn't know one end of his pencil from the other.

 

[rbattelle]

DJW, In my opinion, l/h downhill is simply a case of an engineer who didn't know one end of his pencil from the other.

Impossible. Engineers don't use pencils anymore, they use a keyboard and faithfully reproduce what the screen tells them.



-Ryan

 

[Coalsmoke]

Of course! What was I thinking



See, I can poke fun of engineers in good faith because I started in engineering school before switching to law. If you ever want to feel like an inconsequential speck of dust, sit in a physics lecture with another 150 engineering students all who think they are the countries God given gift. There was enough hot air in their to float a blimp

 

[rbattelle]

before switching to law.

You're a lawyer!? I thought you were a welder!?



-Ryan