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316L SS - Materials science: Pickle and Passivated versus bright annealing

316L SS - Materials science: Pickle and Passivated versus bright annealing

I am a PE working on a construction project that involves the transmission of waste glycerol (from biodiesel production) through a variety of pressurized force mains (24-hours per day, 7-days per week). Our specifications call for all 316L stainless steel piping to be pickled and passivated. Our contractor has proposed one manufacturer that can furnish all the piping for the project, however the manufacturer uses both the pickle and passivation process as well as the bright annealing process to prepare the piping. The manufacturer claims that they cannot furnish all of the piping with only the pickled and passivated treatment. I am trying to make a fact based determination of whether or nor the bright annealing process is technically equivalent to the pickle and passivation process. The purpose of this thread is to request information/insights/feedback on the subject of these two treatments.

I am specifically thinking that a technical substantiation would include the following:
1. What is the intent of the pickle and passivation process? Is the intent of the bright annealing process the same or somewhat different?
2. How is the pickle and passivation process’s effectiveness is measured? What test is available? What data can prove it?
3. How the bright annealing process’s effectiveness is measured. What test is available? What data can prove it?
4. Relative qualitative cost difference (if any)

Thank you in advance for any feedback that you may be able to provide!

RE: 316L SS - Materials science: Pickle and Passivated versus bright annealing

I'd be interested in a response to this.

I'm a MechE. From what I've heard/seen of pressure vessels, the welds are coated in a citric acid paste for the pickling. Not sure if that is done on the seamed pipe, or if ALL of the pipe surface gets hit with that.

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