strange indications on radiograph...help

Date 01-16-2006 11:46

We are getting some strange indications on the radiographs of some welded joints . the joints are between two 8mm plates and a backstrip plate. The indications are discontinuous dark lines at the joint edges (1,1). The indications are similar to high-low type defects seen in butt joints. The plates will form the annular ring of a MS tank. The plates were painted with High Build Coal Tar Epoxy paints ( 3 coats @ 125 micron/coat ) prior to welding. Do anyone had similar experiences ??

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By jfwi

Date 01-16-2006 20:41

I do not has a similar experience by my RT interpretation training says what you describe could be considered a lack of fusion indication. You said the metal was painted prior to welding. If the paint melted into the weld zone this could cause lack of fusion. Other than high/low and lack of fusion I am at a lose. Sorry I could not help more.

By vonash

Date 01-16-2006 21:21

I agree clean your weld areas.

By Shane Feder (****)

Date 01-16-2006 23:49

Asarkar_ kolkata,
The 8 mm plate is reasonably thin and will bend/warp quite easily. If you do not have enough tacks between the 8mm plate and the backing strip keeping it in close contact you will get slag filling the void and this may show as discontinuous indications,
Regards,
Shane Feder

By khodabandeh (**)

Date 01-17-2006 09:47

Dear Sir,
I think the painting prior welding caused linear slag if at start and end of the indication spacifed tail, otherwise it maybe LOF.
Best Regards
O.Khodabandeh

By cryogenicshaun (**)

Date 01-26-2006 11:05

does it run along the weldement or transverse?