Failure Analysis

[Shashank Vagal]

Dear all,

Please suggest what could have caused this pipe failure after Hydrotesting..... Consider all general conditions as all details are not known yet

 

BR,

Shashank C Vagal 

[Alan Denney]

I guess it has failed during hydrotest. Really it needs more detailed pictures of the fracture and the pipe local to the fracture to give sensible opinions. The failure appears to have initiated in the parent material, which is most unusual. That central bit of the failure looks very straight, was there any type of weld there? What is the type of pipe, seamless, resistance or induction welded, submerged arc welded? It will have failed from some type of stress raiser or metallurgical discontinuity; a weld, a score in the pipe, a repair of some sort. You need to get some sections into a metallurgical laboratory for examination.

 

Alan Denney

AKD Materials Consulting Ltd

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[KRISHNASAMY MASANAM]

May be the hydro test pressure exceeding the 90% of SMYS... 

Krishnasamy Masanam

QA/QC Mechanical/Welding Inspector (GIS-TUV)

Saudi Aramco Project Inspection Division,

Saudi Aramco Pipeline Inspection Unit,

TUV-NORD KSA

krishnasa...@aramco.com

+966 564 74 3358

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[Shashank Vagal]

Thanks, Alan. I have asked for more details as it is of a great general interest to all students of failure analysis. I shall make them available on this forum when received.

 

BR,

Shashank C Vagal 

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From: Alan Denney <al...@denney1.freeserve.co.uk>
To: material...@googlegroups.com
Sent: Monday, 22 February 2016 3:08 AM
Subject: [MW:24341] RE: 24334] Failure Analysis

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[c sridhar]

If possible, you can also take a radiography in the same line of failure (seam or seamless) 

to check for any defects in that pipe material. 

 

C Sridhar.
Technical Adviser - Welding,
for Alsta Pristine Engineering Private Limited,. Bangalore
( SS, AL fabricators & A venture of Advance Eng. Training & Inspection Services). Chennai,

Mobile nos: 0 94449 71097, 0 7406 326326, .

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From: 'Shashank Vagal' via Materials & Welding <material...@googlegroups.com>
To: "material...@googlegroups.com" <material...@googlegroups.com>; Nachiket Vagal <nachi...@gmail.com>
Sent: Monday, 22 February 2016 10:10 AM
Subject: Re: [MW:24345] RE: 24334] Failure Analysis

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[Pieper QSI]

Seems to me that it was tested above the minimum specified yield strength of the base material (over pressured) because there is a lot of deformation visible on the picture, if material/weld failures were present in general you will get a brittle fracture. Radiographic examination makes only sense if the present fracture surface shows any indication which may relate to an improper longitudinal weld.

I would suggest checking base material certificate (also check wall thickness with requirements) and execute some tests on the uninfluenced base material in order to check if values comply with the certificate.

Also check calibration of equipment used during testing, was it giving the correct information?

 

Also important to know is the procedure followed during testing. For example in which steps was the test pressure applied, and was the temperature of the water / material during testing.

 

Met vriendelijke groeten / Best Regards,

 

Herman Pieper

QA-QC Inspector / CSWIP + IWI-C Welding Inspector / IWT / Materials Expert

 

Job van der Havestraat 6

8384 DB, Wilhelminaoord

Cell: +31 6 51691215

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