?? oil impregnated steel - welding ??

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Anyone ever welded steel or stainless that's been saturated in oil?   What steps in prep do you take before welding?   I got a job offered to me that I'm skeptical to take.   It entails cutting stainless pipe/tubing that approx 2" or a lil less and weld a couple new elbows on, then weld elbows to other existing stainless pipe.   Basically rerouting some stainless pipe.  The previous welds and repairs are TIG welds.  Looking at the outside of the pipe, I'm guessing it's sched 40 pipe.   My concern is, it's been under pressure for years w/ typical  hydraulic oil.  Is oil impregnated into the walls of the stainless?   What type of cleaning or prep is needed?   It's in a cannery that is in production.  If or when they shut the system down for me to work on, I need to look like I know what I'm doing and have very limited time to make the modifications.   Anyone ever TIG'd stuff like this before? I'd like some advice.    My experience on welding on shafts and parts that have been submerged in gear boxes is that the steel absorbs the gear oil.   I'd take a splined shaft that say spun a bearing.  Well, I'd build up the shaft on the worn area and then turn it down in a lathe.  Problem is, when you strike an arc on the shaft, oil would bubble out of the steel.   Totally contaminating the weld.  So what I'd do is hold a torch on it for several minutes, and watch the oil bubble out and burn off before I welded it.  It's always amazed me the amount of oil that will soak in steel.  I won't even go into the story of the time I tig welded an aluminum oil primary cover on a harley davidson.   So hear I'm faced w/ a similar situation.   It's not steel thats been sitting in 80 90 sae oil, its stainless that's in 10 sae and been under a couple thousand psi for years.  Anyone have any thoughts on this?
Reply:If you can wipe it down with acetone, make sure its dry then and you should be fine.  I've also used denatured alcohol to remove oils.  As far as "impregnated" with oil, your torch solution is also a sound way to do it, provided you consider warpage and tempering issues.   I'd have to say, for a piece of steel to have an abundant amount of oil within it, it must have microscopic fissures possibly due to hydrogen embrittlement introduction.     That alone would be a horrible piece of steel to hold any type of weld in the first place, if the piece was used for a critical "structural" load. Again acetone, steam cleaning, hot soap and water, denatured alcohol, blow torch...... All viable options that you'll have to weigh  the pros & cons of each yourself.Lincoln Power Mig 216Lincoln AC/DC-225/125Miller  625 X-Treme PlasmaMiller 211 Forney 95FI-A 301HF 91110Victor Journeyman O/PMilwaukee DaytonMakita  Baileigh NRA Life Member
Reply:Like said above. Degrease and get to work. Unless it is a casting it welds the same as new.Weld 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:Been on refinery jobs where the weld procedure called for a 'burn out' period.....area was preheated with electric coil system and held at (guessing) 600 degrees for around 6 hours.  Worked a few times, remember once though, we couldn't tig and had to revise and stick weld.  Can't remember if projects were mild or stainless.
Reply:hmm, thank you for the rude news.    I'll have to think about this one.  I always hate to turn down a challenge, but this could really turn into a nightmare, given the time and conditions allowed to do it.
Reply:while some castings are porous enough to absorb a little oil,steel and stainless are not. think about it.if it were that porous,then liquids (especially under pressure)would leak thru to the outside.miller thunderbolt 250vlincoln square wave tig 175 prolincoln idealarc mig sp250everlast tig 210EXTeverlast power plasma 50chicago electric (hf) 130 tig/90 arcchicago electric 90 amp flux wire3 sets oxy/acet
Reply:Originally Posted by boatbuoywhile some castings are porous enough to absorb a little oil,steel and stainless are not. think about it.if it were that porous,then liquids (especially under pressure)would leak thru to the outside.
Reply:123weld.....as to my comment about a weld procedure requiring a burn out period....It's possible we were repairing a known corrosion problem.  Grind out the visible pitting, MPI for cracks, and reweld.  Corrosion is probably not a concern in your case. Any chance you could have a backup plan using socket welds if necessary?
Reply:I don't think it has anything to do with corrosion.   But neither did the spline solid steel shafts out of Ditch Witches I talked about being in gear oil have anything to do with corrosion.        I have avid welders here telling me something I've done and seen with my own two eyes doesn't happen.   So I doubt, I could convince 12 jurors and a judge it wasn't my fault the cannery had to shut down production.  I think I'll be passing on the job.   thanks though.
Reply:Not corrosion but maybe invisible stress fractures?  Would be interesting to do a dye pen test on the shafts.
Reply:actually,according to wikipedia--the typical 59-gallon (225-liter) barrel can lose anywhere from 5½ to 6½ gallons (21 to 25 liters) of wine through the course of evaporation. This evaporation (of mostly alcohol and water) allows the wine to concentrate its flavormiller thunderbolt 250vlincoln square wave tig 175 prolincoln idealarc mig sp250everlast tig 210EXTeverlast power plasma 50chicago electric (hf) 130 tig/90 arcchicago electric 90 amp flux wire3 sets oxy/acet