UT test for inspecting a vessel with plates in SS clad +CS

[lganga]

We have to inspect a vessel fabricated with integral clad plates of 3 mm SS 316 + 30 mm CS thickness. As it is a jacketed vessel, we have only access from the cladded side.(internal side)
We have to do Thickness measures and flaws detection on the longitufinal and circunferential welds.
According to drawings the 316 clad has 3 mm thickness
The CS side, is the strength resistant side and the one we need to be thoroughly inspected.
Do you know some practical technique or UT equipment able to detect it?.
Note : this is a complement of the thead in Boiler and PV forum Nº794 29368.
Regards

 

[rustbuster]

Consider Phased Array UT. You will need a mock up to develop a procedure and qualify the technique and technicians.

 

[lganga]

rustbuster
I am reading about Phased Array UT, about how it could help us to find flaws on the clad plate welds.
We want to check longitudinal and circunferential integral clad welds (T intersections included)
If we consider that the welds has to have low ferrite, almost austenitic, to avoid any corrosion and we have, along the wall welds thickness joints,different dilution that goes from ferritic to austenitic over the clad SS plate (due to the dissimilar welds).
Do you think that Phased Array UT, will give us valuable information?.

 

[Duwe6]

lganga,
Phased Array will find amost all weld flaws using the transducer at an angle of 45-70°, and will find the remaining using the transducer 'straight' sweeping from +15° to -15°. The straight sweep will also locate any lack-of-fusion in the cladding-to-basemetal weld.

 

[ndeguy]

lganga

What is your acceptance criteria?

If your deposited weld metal is ferritic and 30mm thick then perhaps you should investigate TOFD. The 3mm 316 cladding should not interfere significantly. If you apply ToFD ensure your techncian makes full allowance for the cap width (his examination will be from root side) plus HAZ when setting up his probe separation.

Either PA or ToFD, I agree with rustbuster that you will need welded mock-ups containing known flaws, ideally representing the type of flaw you are seeking, at suitable locations.