CTOD test

[Ali Asghari]

Dear All.

How CTOD result is used to establish acceptance criteria for

pipeline girth welds?

Regards.

[Alan Denney]

In a nutshell and very simplified: The CTOD test is a test of the fracture toughness of the material – effectively the ability of the material tested to tolerate a planar flaw. You get a measurement out of the test in mm. You then have to perform fracture mechanics calculations, normally to the requirements of DNV-OS-F101 and BS7910 or using the TWI Crackwise program which is based on the BS. From this you get a tolerable defect size. This tolerable defect size is then used to derive welding defect acceptance criteria for planar flaws. These defect acceptance criteria are then suitable for use but, in my view, only where you are using automatic welding systems and automatic ultrasonic testing systems. A warning: it takes many months of specialist work by welding engineers, fracture mechanics specialists and NDT specialists to get this all done and acceptable.

 

Alan Denney

AKD Materials Consulting Ltd

8 Furber Street

London W6 0HE

Tel: +44 (0)20 8748 0636

Mobile: +44 (0)7786 077125

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[pgoswami]

Hi Ali Asghari,

 

Please see the attached article on incorporating the CTOD test requirements for pipeline welds, with the relevant portions as highlighted. CTOD is  very good concept, but would require significant engineering assessments to be put put in practice as compared to conventional approaches involving Charpy Impact Test.

 

Best regards

 

 

Pradip Goswami, P.Eng,IWE

Welding & Metallurgical Engineer/Specialist

Ontario, Canada

pgos...@quickclic.net

pradip....@gmail.com

 

 

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From: material...@googlegroups.com [mailto:material...@googlegroups.com] On Behalf Of Ali Asghari

Sent: Sunday, August 02, 2015 4:54 AM

To: material...@googlegroups.com
Subject: [MW:23247] CTOD test

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