Fire Retardant Fluid (REOLUBE TURBOFLUID 46XC) and Old Stainless Steel Pipe

[Bambie]

Welders in my plant contend that 40 year old sections of austenitic grade 316 stainless pipe that have carried FRF at 1350 psig and 140 degF cannot be cut out and re-welded because residual FRF cannot be completely driven from the microstructure and contaminates the weld.
I can't find any evidence of this in literature - is there any truth to this?

 

[EdStainless]

Is this a silicone based fluid? If so then they are sort of right, there is no solvent for it to assure that it is clean.
The surfaces will need to be scrubbed with acetone and/or MEK, heated to pyrolyze any remaining chemicals, blasted, and re-cleaned with fresh solvents.
I have had to weld on vacuum equipment that has Si grease on it, it is a bear.

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P.E. Metallurgy, Plymouth Tube

 

[btrueblood]

From a quick google search, it's 100% trixylenyl phosphate, aka a phosphate ester hydraulic fluid, aka brake fluid. I've never heard of brake fluid contaminating steel microstructures, but have never welded a brake line either.

 

[EdStainless]

If it as you say btb (and I would never doubt you) then there are solvents for this, so it can be cleaned.
My guess is that in the past they have tried to use naptha or methanol. Pick the correct solvent and you will be good.

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P.E. Metallurgy, Plymouth Tube

 

[Bambie]

Okay thanks, I'll see what Chemtura recommends for solvents on stainless.