Hi,
Response to Que 1 & 2:-
For determining thickness of Line/Pipe, 2 factors are added to calculated minimum Thickness i.e
Corrosion Allowance and Mill Tolerance (12.5%), now you can play with Mill tolerance but not
with Corrosion Allowance (CA) as it's a predicted corrosion rate for certain design life.
CA does not account for any of the localized corrosion processes identified, applicable for CUI
as well.
Check affected thickness using NDT, see it is below min. calculated thickness + CA, if yes,
then you have got no option other than scrapping that Piece of Line.
If no then excavate that little portion of corroded line, NDT the excavated area and perform a
weld repair with qualified welding procedure, I don't see any issue related to Brittle fracture
Regards
Manpreet Singh
On Feb 14, 10:34 am, ags 36681 wrote:
> Dear friends,
> In our plant especially in refrigeration unit, so many lines (CS) or
> valves have failed insulation, say maintenance did some work on it and
> then not reinsulated, because of this, ice has formed on all over
> these uninsulated location.
>
> Some of the lines are in intermittent service (means alternate
> equipments are being used based on operation requirements, hence CUI
> is also expected),
>
> below doubts need your support to resolve.
> •How these locations will prone to premature failure. (Other than
> external corrosion).
> •Is there any brittle effect on material?
> •Kindly provide some good references to convince the management
> regarding the impact of this on equipments integrity.
>
> Regards,
--
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For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
Response to Que 1 & 2:-
For determining thickness of Line/Pipe, 2 factors are added to calculated minimum Thickness i.e
Corrosion Allowance and Mill Tolerance (12.5%), now you can play with Mill tolerance but not
with Corrosion Allowance (CA) as it's a predicted corrosion rate for certain design life.
CA does not account for any of the localized corrosion processes identified, applicable for CUI
as well.
Check affected thickness using NDT, see it is below min. calculated thickness + CA, if yes,
then you have got no option other than scrapping that Piece of Line.
If no then excavate that little portion of corroded line, NDT the excavated area and perform a
weld repair with qualified welding procedure, I don't see any issue related to Brittle fracture
Regards
Manpreet Singh
On Feb 14, 10:34 am, ags 36681
> Dear friends,
> In our plant especially in refrigeration unit, so many lines (CS) or
> valves have failed insulation, say maintenance did some work on it and
> then not reinsulated, because of this, ice has formed on all over
> these uninsulated location.
>
> Some of the lines are in intermittent service (means alternate
> equipments are being used based on operation requirements, hence CUI
> is also expected),
>
> below doubts need your support to resolve.
> •How these locations will prone to premature failure. (Other than
> external corrosion).
> •Is there any brittle effect on material?
> •Kindly provide some good references to convince the management
> regarding the impact of this on equipments integrity.
>
> Regards,
--
To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for
educational purposes only, Users must take their own decisions w.r.t. applicable
code/standard/contract documents.
 |
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To post to this group, send email to materials-welding@googlegroups.com
To unsubscribe from this group, send email to materials-welding+unsubscribe@googlegroups.com
For more options, visit this group's bolg at http://materials-welding.blogspot.com/
The views expressed/exchnaged in this group are members personel views and meant for educational purposes only, Users must take their own decisions w.r.t. applicable code/standard/contract documents.
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