MPI on galvanized pipes 1

[Hansac]

Dear all

Is it possible to do MPI on weldment on a pipe that has already been galvanized? The galvanizing took place _after_ the welding. The galvanizing thickness is about 85 microns to 150 microns.

What is the maximum coating thickness (both galvanize and regular painting) that allows for MPI?

Thank you very much in advance.

 

[Hansac]

I've checked around and this question was posted in another group. Apologies for that!

 

[metengr]

No, MPI is not permitted on material that has a barrier coating. The coating must be removed for proper interpretation.

 

[mfgenggear]

is welding on galvanized coating very hazardous? I would be reluctant to weld on galvanize.

I would think the the welded area would be ok to MPI since the coating has to be removed & prepped for weldment.
I not a expert on these matters so it is subject to the experts.
I have had customers request MPI over other types of plating such as chrome, but here lays the question. is
it doable.

HTH
Mfgenggear

 

[cloa]

The OP didn't say he was welding on galvanised rather he had galvanised a weld.

 

[mfgenggear]

cloa

My mistake thanks for the correction.

Mfgenggear

 

[phighfill]

I agree with metengr on this. MPI will not sufficiently detect anything below the galvanizing.

 

[Hansac]

I read somewhere else in eng-tips as well as googling up, there is a case for doing MPI on galvanized steel. It seems that if you have enough magnetizing force, you could get some reading, albeit perhaps weak.