Re- passivation 316L ss demi water loop
Re- passivation 316L ss demi water loop
(OP)
Hello,
I have a question about passive layer in the pipeline of 316L ss ? I have a demi water loop (water velocity is over 1.1 m/s, conductivity is about 0.5 uS, temp. about 20 deg C). As I know the thickness of passive layer is about couple particles. Is that possible the water after some time breaks off (wash up) the layer ?
Is that recommended to make a repassivation the ss surface after some time ? If so, do you know some standard (i.e. ISO, ASTM etc.) that treats of ?
Thanks for your help.
Regards
I have a question about passive layer in the pipeline of 316L ss ? I have a demi water loop (water velocity is over 1.1 m/s, conductivity is about 0.5 uS, temp. about 20 deg C). As I know the thickness of passive layer is about couple particles. Is that possible the water after some time breaks off (wash up) the layer ?
Is that recommended to make a repassivation the ss surface after some time ? If so, do you know some standard (i.e. ISO, ASTM etc.) that treats of ?
Thanks for your help.
Regards





RE: Re- passivation 316L ss demi water loop
Flow velocities of 20m/s have been shown to have no impact on the corrosion potentials of SS.
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Plymouth Tube
RE: Re- passivation 316L ss demi water loop
You said "chemically depassivated (acid)", as I know, the demi water is in acid pH area (in my loop about 6.5)Anyway isn't an acid a passivated medium ?
One more thing: Have you got some paper about this flow velocities of 20 m/s not breaking of the passive layer ?
Kind Regards
RE: Re- passivation 316L ss demi water loop
You passivate in an oxidizing acid, There are low pH environments that will break down the passive layer either because they are reducing of very low pH (<3).
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Plymouth Tube
RE: Re- passivation 316L ss demi water loop
Additionally I would like to know the system volume and the amount of chloride.
Regards,
M. Arguelles
RE: Re- passivation 316L ss demi water loop
I can not add any filter in PW loop, after EDI there sould not be any additional filters.
Anyway, I will check the concentrations of chloride. The main problem in PW is not the erosion. I was just courious if there should be made re-passivation after some time.
RE: Re- passivation 316L ss demi water loop
RE: Re- passivation 316L ss demi water loop
Demi water means purified water without any additives. So I can not add any substance to purified water after EDI, inhibitors neighter.
Anyway, what influence do amines film have on bacterial growth ?
Regards.
RE: Re- passivation 316L ss demi water loop
RE: Re- passivation 316L ss demi water loop
No big deal.
Yes you can get biological growth is a system like this. Unless your initial sterilization was very aggressive and you have some ongoing biological control. (UV or H2O2)
No, passivation never wears out. Unless you work on the system (new parts), contaminate the system, or have a significant erosion issue there is no reason to ever re-passivate.
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Plymouth Tube
RE: Re- passivation 316L ss demi water loop
There would be little value in repassivation.
RE: Re- passivation 316L ss demi water loop