[img]file:///C:/Documents%20and%20Settings/npandya/Desktop/P111211_09.20.jpg[/img]

We have fabricated 4m dia 10mtr lg Column All shop test were succeeded and found leak at Site during commissioning from HAZ parent metal.

MOC is SA240 Uns41003 for sugar refinery.

Wht could be reason ?

Hardness found at that area Ranging between - 210 to 240 HB.

Definitely we will have interesting failure analysis ahead.

_________________
Niraj

Dear Niraj:

I would dare assuming that the failure you describe is a brittle weld fracture.

Ferritic class of stainless steels is known to be sensitive to high weld heat input or to occasionally warming the part before forming, resulting in low impact toughness.

I agree with you shmulik, but......
Is UNS41003 an alloy of SA 240?
I find it in Sect. IX as SA-1010 alloy S41003 (12Cr-1Ni). is it not a martensitic alloy? In this case crack should not be a surprise.
Mauro

See code case 2696 .
There could be several reasons why the crack happend. Till an analysis is carried out ,we can not rule out any cause .
Was LPT carried out on all Weld Seams ?

Dear Mr. Mauro:
Thank you for enlighten this point (and for forcing me to reread the code regarding to this subject).

Alloy S41003 appears as SA-1010 at ASME II Part D and so at VIII-1 Table UHA-23, all as a plate product form (as far as I recall, this material, 3CR12® was formerly certified to ASTM A-240, UNS S41003 - but wasn't certified for pressure purposes).

S41003 belongs to P-No. 7 (which contain the Ferritic alloys).

ASME VIII-1 Table UHA-32 P-No. 7 Note (1) address PWHT and very slow cooling rate of max. 56 ºC/Hr when carbon content exceeds 0.08%.
Thickness over 10 mm requires preheat of 230 ºC maintained during welding, and joints are to be completely radiographed.

Author of this question hasn't mentioned his material's thickness or carbon content. In what regard to carbon content - I would not be satisfied with materials mill test cert, but check it positively.

My initial response is that the main reason of leakage is high hardness, upto 240HB.

Would request you to describe the WPS/NDTs adopted.

Thanks to all for valuable reply.

Thickness is 16mm and lab test carbon Content is 0.06% ( surprisingly low).

Our initial outcome is due to martensite formation delayed crack observed .

All weld joint 100% Radiographed during fabrication.

We will have test sample in next week for testing.

_________________
Niraj